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Linux/net/core/dev.c

  1 /*
  2  *      NET3    Protocol independent device support routines.
  3  *
  4  *              This program is free software; you can redistribute it and/or
  5  *              modify it under the terms of the GNU General Public License
  6  *              as published by the Free Software Foundation; either version
  7  *              2 of the License, or (at your option) any later version.
  8  *
  9  *      Derived from the non IP parts of dev.c 1.0.19
 10  *              Authors:        Ross Biro
 11  *                              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 12  *                              Mark Evans, <evansmp@uhura.aston.ac.uk>
 13  *
 14  *      Additional Authors:
 15  *              Florian la Roche <rzsfl@rz.uni-sb.de>
 16  *              Alan Cox <gw4pts@gw4pts.ampr.org>
 17  *              David Hinds <dahinds@users.sourceforge.net>
 18  *              Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
 19  *              Adam Sulmicki <adam@cfar.umd.edu>
 20  *              Pekka Riikonen <priikone@poesidon.pspt.fi>
 21  *
 22  *      Changes:
 23  *              D.J. Barrow     :       Fixed bug where dev->refcnt gets set
 24  *                                      to 2 if register_netdev gets called
 25  *                                      before net_dev_init & also removed a
 26  *                                      few lines of code in the process.
 27  *              Alan Cox        :       device private ioctl copies fields back.
 28  *              Alan Cox        :       Transmit queue code does relevant
 29  *                                      stunts to keep the queue safe.
 30  *              Alan Cox        :       Fixed double lock.
 31  *              Alan Cox        :       Fixed promisc NULL pointer trap
 32  *              ????????        :       Support the full private ioctl range
 33  *              Alan Cox        :       Moved ioctl permission check into
 34  *                                      drivers
 35  *              Tim Kordas      :       SIOCADDMULTI/SIOCDELMULTI
 36  *              Alan Cox        :       100 backlog just doesn't cut it when
 37  *                                      you start doing multicast video 8)
 38  *              Alan Cox        :       Rewrote net_bh and list manager.
 39  *              Alan Cox        :       Fix ETH_P_ALL echoback lengths.
 40  *              Alan Cox        :       Took out transmit every packet pass
 41  *                                      Saved a few bytes in the ioctl handler
 42  *              Alan Cox        :       Network driver sets packet type before
 43  *                                      calling netif_rx. Saves a function
 44  *                                      call a packet.
 45  *              Alan Cox        :       Hashed net_bh()
 46  *              Richard Kooijman:       Timestamp fixes.
 47  *              Alan Cox        :       Wrong field in SIOCGIFDSTADDR
 48  *              Alan Cox        :       Device lock protection.
 49  *              Alan Cox        :       Fixed nasty side effect of device close
 50  *                                      changes.
 51  *              Rudi Cilibrasi  :       Pass the right thing to
 52  *                                      set_mac_address()
 53  *              Dave Miller     :       32bit quantity for the device lock to
 54  *                                      make it work out on a Sparc.
 55  *              Bjorn Ekwall    :       Added KERNELD hack.
 56  *              Alan Cox        :       Cleaned up the backlog initialise.
 57  *              Craig Metz      :       SIOCGIFCONF fix if space for under
 58  *                                      1 device.
 59  *          Thomas Bogendoerfer :       Return ENODEV for dev_open, if there
 60  *                                      is no device open function.
 61  *              Andi Kleen      :       Fix error reporting for SIOCGIFCONF
 62  *          Michael Chastain    :       Fix signed/unsigned for SIOCGIFCONF
 63  *              Cyrus Durgin    :       Cleaned for KMOD
 64  *              Adam Sulmicki   :       Bug Fix : Network Device Unload
 65  *                                      A network device unload needs to purge
 66  *                                      the backlog queue.
 67  *      Paul Rusty Russell      :       SIOCSIFNAME
 68  *              Pekka Riikonen  :       Netdev boot-time settings code
 69  *              Andrew Morton   :       Make unregister_netdevice wait
 70  *                                      indefinitely on dev->refcnt
 71  *              J Hadi Salim    :       - Backlog queue sampling
 72  *                                      - netif_rx() feedback
 73  */
 74 
 75 #include <asm/uaccess.h>
 76 #include <linux/bitops.h>
 77 #include <linux/capability.h>
 78 #include <linux/cpu.h>
 79 #include <linux/types.h>
 80 #include <linux/kernel.h>
 81 #include <linux/hash.h>
 82 #include <linux/slab.h>
 83 #include <linux/sched.h>
 84 #include <linux/mutex.h>
 85 #include <linux/string.h>
 86 #include <linux/mm.h>
 87 #include <linux/socket.h>
 88 #include <linux/sockios.h>
 89 #include <linux/errno.h>
 90 #include <linux/interrupt.h>
 91 #include <linux/if_ether.h>
 92 #include <linux/netdevice.h>
 93 #include <linux/etherdevice.h>
 94 #include <linux/ethtool.h>
 95 #include <linux/notifier.h>
 96 #include <linux/skbuff.h>
 97 #include <net/net_namespace.h>
 98 #include <net/sock.h>
 99 #include <linux/rtnetlink.h>
100 #include <linux/stat.h>
101 #include <net/dst.h>
102 #include <net/pkt_sched.h>
103 #include <net/checksum.h>
104 #include <net/xfrm.h>
105 #include <linux/highmem.h>
106 #include <linux/init.h>
107 #include <linux/module.h>
108 #include <linux/netpoll.h>
109 #include <linux/rcupdate.h>
110 #include <linux/delay.h>
111 #include <net/iw_handler.h>
112 #include <asm/current.h>
113 #include <linux/audit.h>
114 #include <linux/dmaengine.h>
115 #include <linux/err.h>
116 #include <linux/ctype.h>
117 #include <linux/if_arp.h>
118 #include <linux/if_vlan.h>
119 #include <linux/ip.h>
120 #include <net/ip.h>
121 #include <linux/ipv6.h>
122 #include <linux/in.h>
123 #include <linux/jhash.h>
124 #include <linux/random.h>
125 #include <trace/events/napi.h>
126 #include <trace/events/net.h>
127 #include <trace/events/skb.h>
128 #include <linux/pci.h>
129 #include <linux/inetdevice.h>
130 #include <linux/cpu_rmap.h>
131 #include <linux/static_key.h>
132 #include <linux/hashtable.h>
133 #include <linux/vmalloc.h>
134 #include <linux/if_macvlan.h>
135 
136 #include "net-sysfs.h"
137 
138 /* Instead of increasing this, you should create a hash table. */
139 #define MAX_GRO_SKBS 8
140 
141 /* This should be increased if a protocol with a bigger head is added. */
142 #define GRO_MAX_HEAD (MAX_HEADER + 128)
143 
144 static DEFINE_SPINLOCK(ptype_lock);
145 static DEFINE_SPINLOCK(offload_lock);
146 struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
147 struct list_head ptype_all __read_mostly;       /* Taps */
148 static struct list_head offload_base __read_mostly;
149 
150 static int netif_rx_internal(struct sk_buff *skb);
151 
152 /*
153  * The @dev_base_head list is protected by @dev_base_lock and the rtnl
154  * semaphore.
155  *
156  * Pure readers hold dev_base_lock for reading, or rcu_read_lock()
157  *
158  * Writers must hold the rtnl semaphore while they loop through the
159  * dev_base_head list, and hold dev_base_lock for writing when they do the
160  * actual updates.  This allows pure readers to access the list even
161  * while a writer is preparing to update it.
162  *
163  * To put it another way, dev_base_lock is held for writing only to
164  * protect against pure readers; the rtnl semaphore provides the
165  * protection against other writers.
166  *
167  * See, for example usages, register_netdevice() and
168  * unregister_netdevice(), which must be called with the rtnl
169  * semaphore held.
170  */
171 DEFINE_RWLOCK(dev_base_lock);
172 EXPORT_SYMBOL(dev_base_lock);
173 
174 /* protects napi_hash addition/deletion and napi_gen_id */
175 static DEFINE_SPINLOCK(napi_hash_lock);
176 
177 static unsigned int napi_gen_id;
178 static DEFINE_HASHTABLE(napi_hash, 8);
179 
180 static seqcount_t devnet_rename_seq;
181 
182 static inline void dev_base_seq_inc(struct net *net)
183 {
184         while (++net->dev_base_seq == 0);
185 }
186 
187 static inline struct hlist_head *dev_name_hash(struct net *net, const char *name)
188 {
189         unsigned int hash = full_name_hash(name, strnlen(name, IFNAMSIZ));
190 
191         return &net->dev_name_head[hash_32(hash, NETDEV_HASHBITS)];
192 }
193 
194 static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
195 {
196         return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 1)];
197 }
198 
199 static inline void rps_lock(struct softnet_data *sd)
200 {
201 #ifdef CONFIG_RPS
202         spin_lock(&sd->input_pkt_queue.lock);
203 #endif
204 }
205 
206 static inline void rps_unlock(struct softnet_data *sd)
207 {
208 #ifdef CONFIG_RPS
209         spin_unlock(&sd->input_pkt_queue.lock);
210 #endif
211 }
212 
213 /* Device list insertion */
214 static void list_netdevice(struct net_device *dev)
215 {
216         struct net *net = dev_net(dev);
217 
218         ASSERT_RTNL();
219 
220         write_lock_bh(&dev_base_lock);
221         list_add_tail_rcu(&dev->dev_list, &net->dev_base_head);
222         hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
223         hlist_add_head_rcu(&dev->index_hlist,
224                            dev_index_hash(net, dev->ifindex));
225         write_unlock_bh(&dev_base_lock);
226 
227         dev_base_seq_inc(net);
228 }
229 
230 /* Device list removal
231  * caller must respect a RCU grace period before freeing/reusing dev
232  */
233 static void unlist_netdevice(struct net_device *dev)
234 {
235         ASSERT_RTNL();
236 
237         /* Unlink dev from the device chain */
238         write_lock_bh(&dev_base_lock);
239         list_del_rcu(&dev->dev_list);
240         hlist_del_rcu(&dev->name_hlist);
241         hlist_del_rcu(&dev->index_hlist);
242         write_unlock_bh(&dev_base_lock);
243 
244         dev_base_seq_inc(dev_net(dev));
245 }
246 
247 /*
248  *      Our notifier list
249  */
250 
251 static RAW_NOTIFIER_HEAD(netdev_chain);
252 
253 /*
254  *      Device drivers call our routines to queue packets here. We empty the
255  *      queue in the local softnet handler.
256  */
257 
258 DEFINE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
259 EXPORT_PER_CPU_SYMBOL(softnet_data);
260 
261 #ifdef CONFIG_LOCKDEP
262 /*
263  * register_netdevice() inits txq->_xmit_lock and sets lockdep class
264  * according to dev->type
265  */
266 static const unsigned short netdev_lock_type[] =
267         {ARPHRD_NETROM, ARPHRD_ETHER, ARPHRD_EETHER, ARPHRD_AX25,
268          ARPHRD_PRONET, ARPHRD_CHAOS, ARPHRD_IEEE802, ARPHRD_ARCNET,
269          ARPHRD_APPLETLK, ARPHRD_DLCI, ARPHRD_ATM, ARPHRD_METRICOM,
270          ARPHRD_IEEE1394, ARPHRD_EUI64, ARPHRD_INFINIBAND, ARPHRD_SLIP,
271          ARPHRD_CSLIP, ARPHRD_SLIP6, ARPHRD_CSLIP6, ARPHRD_RSRVD,
272          ARPHRD_ADAPT, ARPHRD_ROSE, ARPHRD_X25, ARPHRD_HWX25,
273          ARPHRD_PPP, ARPHRD_CISCO, ARPHRD_LAPB, ARPHRD_DDCMP,
274          ARPHRD_RAWHDLC, ARPHRD_TUNNEL, ARPHRD_TUNNEL6, ARPHRD_FRAD,
275          ARPHRD_SKIP, ARPHRD_LOOPBACK, ARPHRD_LOCALTLK, ARPHRD_FDDI,
276          ARPHRD_BIF, ARPHRD_SIT, ARPHRD_IPDDP, ARPHRD_IPGRE,
277          ARPHRD_PIMREG, ARPHRD_HIPPI, ARPHRD_ASH, ARPHRD_ECONET,
278          ARPHRD_IRDA, ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL,
279          ARPHRD_FCFABRIC, ARPHRD_IEEE80211, ARPHRD_IEEE80211_PRISM,
280          ARPHRD_IEEE80211_RADIOTAP, ARPHRD_PHONET, ARPHRD_PHONET_PIPE,
281          ARPHRD_IEEE802154, ARPHRD_VOID, ARPHRD_NONE};
282 
283 static const char *const netdev_lock_name[] =
284         {"_xmit_NETROM", "_xmit_ETHER", "_xmit_EETHER", "_xmit_AX25",
285          "_xmit_PRONET", "_xmit_CHAOS", "_xmit_IEEE802", "_xmit_ARCNET",
286          "_xmit_APPLETLK", "_xmit_DLCI", "_xmit_ATM", "_xmit_METRICOM",
287          "_xmit_IEEE1394", "_xmit_EUI64", "_xmit_INFINIBAND", "_xmit_SLIP",
288          "_xmit_CSLIP", "_xmit_SLIP6", "_xmit_CSLIP6", "_xmit_RSRVD",
289          "_xmit_ADAPT", "_xmit_ROSE", "_xmit_X25", "_xmit_HWX25",
290          "_xmit_PPP", "_xmit_CISCO", "_xmit_LAPB", "_xmit_DDCMP",
291          "_xmit_RAWHDLC", "_xmit_TUNNEL", "_xmit_TUNNEL6", "_xmit_FRAD",
292          "_xmit_SKIP", "_xmit_LOOPBACK", "_xmit_LOCALTLK", "_xmit_FDDI",
293          "_xmit_BIF", "_xmit_SIT", "_xmit_IPDDP", "_xmit_IPGRE",
294          "_xmit_PIMREG", "_xmit_HIPPI", "_xmit_ASH", "_xmit_ECONET",
295          "_xmit_IRDA", "_xmit_FCPP", "_xmit_FCAL", "_xmit_FCPL",
296          "_xmit_FCFABRIC", "_xmit_IEEE80211", "_xmit_IEEE80211_PRISM",
297          "_xmit_IEEE80211_RADIOTAP", "_xmit_PHONET", "_xmit_PHONET_PIPE",
298          "_xmit_IEEE802154", "_xmit_VOID", "_xmit_NONE"};
299 
300 static struct lock_class_key netdev_xmit_lock_key[ARRAY_SIZE(netdev_lock_type)];
301 static struct lock_class_key netdev_addr_lock_key[ARRAY_SIZE(netdev_lock_type)];
302 
303 static inline unsigned short netdev_lock_pos(unsigned short dev_type)
304 {
305         int i;
306 
307         for (i = 0; i < ARRAY_SIZE(netdev_lock_type); i++)
308                 if (netdev_lock_type[i] == dev_type)
309                         return i;
310         /* the last key is used by default */
311         return ARRAY_SIZE(netdev_lock_type) - 1;
312 }
313 
314 static inline void netdev_set_xmit_lockdep_class(spinlock_t *lock,
315                                                  unsigned short dev_type)
316 {
317         int i;
318 
319         i = netdev_lock_pos(dev_type);
320         lockdep_set_class_and_name(lock, &netdev_xmit_lock_key[i],
321                                    netdev_lock_name[i]);
322 }
323 
324 static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
325 {
326         int i;
327 
328         i = netdev_lock_pos(dev->type);
329         lockdep_set_class_and_name(&dev->addr_list_lock,
330                                    &netdev_addr_lock_key[i],
331                                    netdev_lock_name[i]);
332 }
333 #else
334 static inline void netdev_set_xmit_lockdep_class(spinlock_t *lock,
335                                                  unsigned short dev_type)
336 {
337 }
338 static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
339 {
340 }
341 #endif
342 
343 /*******************************************************************************
344 
345                 Protocol management and registration routines
346 
347 *******************************************************************************/
348 
349 /*
350  *      Add a protocol ID to the list. Now that the input handler is
351  *      smarter we can dispense with all the messy stuff that used to be
352  *      here.
353  *
354  *      BEWARE!!! Protocol handlers, mangling input packets,
355  *      MUST BE last in hash buckets and checking protocol handlers
356  *      MUST start from promiscuous ptype_all chain in net_bh.
357  *      It is true now, do not change it.
358  *      Explanation follows: if protocol handler, mangling packet, will
359  *      be the first on list, it is not able to sense, that packet
360  *      is cloned and should be copied-on-write, so that it will
361  *      change it and subsequent readers will get broken packet.
362  *                                                      --ANK (980803)
363  */
364 
365 static inline struct list_head *ptype_head(const struct packet_type *pt)
366 {
367         if (pt->type == htons(ETH_P_ALL))
368                 return &ptype_all;
369         else
370                 return &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK];
371 }
372 
373 /**
374  *      dev_add_pack - add packet handler
375  *      @pt: packet type declaration
376  *
377  *      Add a protocol handler to the networking stack. The passed &packet_type
378  *      is linked into kernel lists and may not be freed until it has been
379  *      removed from the kernel lists.
380  *
381  *      This call does not sleep therefore it can not
382  *      guarantee all CPU's that are in middle of receiving packets
383  *      will see the new packet type (until the next received packet).
384  */
385 
386 void dev_add_pack(struct packet_type *pt)
387 {
388         struct list_head *head = ptype_head(pt);
389 
390         spin_lock(&ptype_lock);
391         list_add_rcu(&pt->list, head);
392         spin_unlock(&ptype_lock);
393 }
394 EXPORT_SYMBOL(dev_add_pack);
395 
396 /**
397  *      __dev_remove_pack        - remove packet handler
398  *      @pt: packet type declaration
399  *
400  *      Remove a protocol handler that was previously added to the kernel
401  *      protocol handlers by dev_add_pack(). The passed &packet_type is removed
402  *      from the kernel lists and can be freed or reused once this function
403  *      returns.
404  *
405  *      The packet type might still be in use by receivers
406  *      and must not be freed until after all the CPU's have gone
407  *      through a quiescent state.
408  */
409 void __dev_remove_pack(struct packet_type *pt)
410 {
411         struct list_head *head = ptype_head(pt);
412         struct packet_type *pt1;
413 
414         spin_lock(&ptype_lock);
415 
416         list_for_each_entry(pt1, head, list) {
417                 if (pt == pt1) {
418                         list_del_rcu(&pt->list);
419                         goto out;
420                 }
421         }
422 
423         pr_warn("dev_remove_pack: %p not found\n", pt);
424 out:
425         spin_unlock(&ptype_lock);
426 }
427 EXPORT_SYMBOL(__dev_remove_pack);
428 
429 /**
430  *      dev_remove_pack  - remove packet handler
431  *      @pt: packet type declaration
432  *
433  *      Remove a protocol handler that was previously added to the kernel
434  *      protocol handlers by dev_add_pack(). The passed &packet_type is removed
435  *      from the kernel lists and can be freed or reused once this function
436  *      returns.
437  *
438  *      This call sleeps to guarantee that no CPU is looking at the packet
439  *      type after return.
440  */
441 void dev_remove_pack(struct packet_type *pt)
442 {
443         __dev_remove_pack(pt);
444 
445         synchronize_net();
446 }
447 EXPORT_SYMBOL(dev_remove_pack);
448 
449 
450 /**
451  *      dev_add_offload - register offload handlers
452  *      @po: protocol offload declaration
453  *
454  *      Add protocol offload handlers to the networking stack. The passed
455  *      &proto_offload is linked into kernel lists and may not be freed until
456  *      it has been removed from the kernel lists.
457  *
458  *      This call does not sleep therefore it can not
459  *      guarantee all CPU's that are in middle of receiving packets
460  *      will see the new offload handlers (until the next received packet).
461  */
462 void dev_add_offload(struct packet_offload *po)
463 {
464         struct list_head *head = &offload_base;
465 
466         spin_lock(&offload_lock);
467         list_add_rcu(&po->list, head);
468         spin_unlock(&offload_lock);
469 }
470 EXPORT_SYMBOL(dev_add_offload);
471 
472 /**
473  *      __dev_remove_offload     - remove offload handler
474  *      @po: packet offload declaration
475  *
476  *      Remove a protocol offload handler that was previously added to the
477  *      kernel offload handlers by dev_add_offload(). The passed &offload_type
478  *      is removed from the kernel lists and can be freed or reused once this
479  *      function returns.
480  *
481  *      The packet type might still be in use by receivers
482  *      and must not be freed until after all the CPU's have gone
483  *      through a quiescent state.
484  */
485 static void __dev_remove_offload(struct packet_offload *po)
486 {
487         struct list_head *head = &offload_base;
488         struct packet_offload *po1;
489 
490         spin_lock(&offload_lock);
491 
492         list_for_each_entry(po1, head, list) {
493                 if (po == po1) {
494                         list_del_rcu(&po->list);
495                         goto out;
496                 }
497         }
498 
499         pr_warn("dev_remove_offload: %p not found\n", po);
500 out:
501         spin_unlock(&offload_lock);
502 }
503 
504 /**
505  *      dev_remove_offload       - remove packet offload handler
506  *      @po: packet offload declaration
507  *
508  *      Remove a packet offload handler that was previously added to the kernel
509  *      offload handlers by dev_add_offload(). The passed &offload_type is
510  *      removed from the kernel lists and can be freed or reused once this
511  *      function returns.
512  *
513  *      This call sleeps to guarantee that no CPU is looking at the packet
514  *      type after return.
515  */
516 void dev_remove_offload(struct packet_offload *po)
517 {
518         __dev_remove_offload(po);
519 
520         synchronize_net();
521 }
522 EXPORT_SYMBOL(dev_remove_offload);
523 
524 /******************************************************************************
525 
526                       Device Boot-time Settings Routines
527 
528 *******************************************************************************/
529 
530 /* Boot time configuration table */
531 static struct netdev_boot_setup dev_boot_setup[NETDEV_BOOT_SETUP_MAX];
532 
533 /**
534  *      netdev_boot_setup_add   - add new setup entry
535  *      @name: name of the device
536  *      @map: configured settings for the device
537  *
538  *      Adds new setup entry to the dev_boot_setup list.  The function
539  *      returns 0 on error and 1 on success.  This is a generic routine to
540  *      all netdevices.
541  */
542 static int netdev_boot_setup_add(char *name, struct ifmap *map)
543 {
544         struct netdev_boot_setup *s;
545         int i;
546 
547         s = dev_boot_setup;
548         for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
549                 if (s[i].name[0] == '\0' || s[i].name[0] == ' ') {
550                         memset(s[i].name, 0, sizeof(s[i].name));
551                         strlcpy(s[i].name, name, IFNAMSIZ);
552                         memcpy(&s[i].map, map, sizeof(s[i].map));
553                         break;
554                 }
555         }
556 
557         return i >= NETDEV_BOOT_SETUP_MAX ? 0 : 1;
558 }
559 
560 /**
561  *      netdev_boot_setup_check - check boot time settings
562  *      @dev: the netdevice
563  *
564  *      Check boot time settings for the device.
565  *      The found settings are set for the device to be used
566  *      later in the device probing.
567  *      Returns 0 if no settings found, 1 if they are.
568  */
569 int netdev_boot_setup_check(struct net_device *dev)
570 {
571         struct netdev_boot_setup *s = dev_boot_setup;
572         int i;
573 
574         for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++) {
575                 if (s[i].name[0] != '\0' && s[i].name[0] != ' ' &&
576                     !strcmp(dev->name, s[i].name)) {
577                         dev->irq        = s[i].map.irq;
578                         dev->base_addr  = s[i].map.base_addr;
579                         dev->mem_start  = s[i].map.mem_start;
580                         dev->mem_end    = s[i].map.mem_end;
581                         return 1;
582                 }
583         }
584         return 0;
585 }
586 EXPORT_SYMBOL(netdev_boot_setup_check);
587 
588 
589 /**
590  *      netdev_boot_base        - get address from boot time settings
591  *      @prefix: prefix for network device
592  *      @unit: id for network device
593  *
594  *      Check boot time settings for the base address of device.
595  *      The found settings are set for the device to be used
596  *      later in the device probing.
597  *      Returns 0 if no settings found.
598  */
599 unsigned long netdev_boot_base(const char *prefix, int unit)
600 {
601         const struct netdev_boot_setup *s = dev_boot_setup;
602         char name[IFNAMSIZ];
603         int i;
604 
605         sprintf(name, "%s%d", prefix, unit);
606 
607         /*
608          * If device already registered then return base of 1
609          * to indicate not to probe for this interface
610          */
611         if (__dev_get_by_name(&init_net, name))
612                 return 1;
613 
614         for (i = 0; i < NETDEV_BOOT_SETUP_MAX; i++)
615                 if (!strcmp(name, s[i].name))
616                         return s[i].map.base_addr;
617         return 0;
618 }
619 
620 /*
621  * Saves at boot time configured settings for any netdevice.
622  */
623 int __init netdev_boot_setup(char *str)
624 {
625         int ints[5];
626         struct ifmap map;
627 
628         str = get_options(str, ARRAY_SIZE(ints), ints);
629         if (!str || !*str)
630                 return 0;
631 
632         /* Save settings */
633         memset(&map, 0, sizeof(map));
634         if (ints[0] > 0)
635                 map.irq = ints[1];
636         if (ints[0] > 1)
637                 map.base_addr = ints[2];
638         if (ints[0] > 2)
639                 map.mem_start = ints[3];
640         if (ints[0] > 3)
641                 map.mem_end = ints[4];
642 
643         /* Add new entry to the list */
644         return netdev_boot_setup_add(str, &map);
645 }
646 
647 __setup("netdev=", netdev_boot_setup);
648 
649 /*******************************************************************************
650 
651                             Device Interface Subroutines
652 
653 *******************************************************************************/
654 
655 /**
656  *      __dev_get_by_name       - find a device by its name
657  *      @net: the applicable net namespace
658  *      @name: name to find
659  *
660  *      Find an interface by name. Must be called under RTNL semaphore
661  *      or @dev_base_lock. If the name is found a pointer to the device
662  *      is returned. If the name is not found then %NULL is returned. The
663  *      reference counters are not incremented so the caller must be
664  *      careful with locks.
665  */
666 
667 struct net_device *__dev_get_by_name(struct net *net, const char *name)
668 {
669         struct net_device *dev;
670         struct hlist_head *head = dev_name_hash(net, name);
671 
672         hlist_for_each_entry(dev, head, name_hlist)
673                 if (!strncmp(dev->name, name, IFNAMSIZ))
674                         return dev;
675 
676         return NULL;
677 }
678 EXPORT_SYMBOL(__dev_get_by_name);
679 
680 /**
681  *      dev_get_by_name_rcu     - find a device by its name
682  *      @net: the applicable net namespace
683  *      @name: name to find
684  *
685  *      Find an interface by name.
686  *      If the name is found a pointer to the device is returned.
687  *      If the name is not found then %NULL is returned.
688  *      The reference counters are not incremented so the caller must be
689  *      careful with locks. The caller must hold RCU lock.
690  */
691 
692 struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
693 {
694         struct net_device *dev;
695         struct hlist_head *head = dev_name_hash(net, name);
696 
697         hlist_for_each_entry_rcu(dev, head, name_hlist)
698                 if (!strncmp(dev->name, name, IFNAMSIZ))
699                         return dev;
700 
701         return NULL;
702 }
703 EXPORT_SYMBOL(dev_get_by_name_rcu);
704 
705 /**
706  *      dev_get_by_name         - find a device by its name
707  *      @net: the applicable net namespace
708  *      @name: name to find
709  *
710  *      Find an interface by name. This can be called from any
711  *      context and does its own locking. The returned handle has
712  *      the usage count incremented and the caller must use dev_put() to
713  *      release it when it is no longer needed. %NULL is returned if no
714  *      matching device is found.
715  */
716 
717 struct net_device *dev_get_by_name(struct net *net, const char *name)
718 {
719         struct net_device *dev;
720 
721         rcu_read_lock();
722         dev = dev_get_by_name_rcu(net, name);
723         if (dev)
724                 dev_hold(dev);
725         rcu_read_unlock();
726         return dev;
727 }
728 EXPORT_SYMBOL(dev_get_by_name);
729 
730 /**
731  *      __dev_get_by_index - find a device by its ifindex
732  *      @net: the applicable net namespace
733  *      @ifindex: index of device
734  *
735  *      Search for an interface by index. Returns %NULL if the device
736  *      is not found or a pointer to the device. The device has not
737  *      had its reference counter increased so the caller must be careful
738  *      about locking. The caller must hold either the RTNL semaphore
739  *      or @dev_base_lock.
740  */
741 
742 struct net_device *__dev_get_by_index(struct net *net, int ifindex)
743 {
744         struct net_device *dev;
745         struct hlist_head *head = dev_index_hash(net, ifindex);
746 
747         hlist_for_each_entry(dev, head, index_hlist)
748                 if (dev->ifindex == ifindex)
749                         return dev;
750 
751         return NULL;
752 }
753 EXPORT_SYMBOL(__dev_get_by_index);
754 
755 /**
756  *      dev_get_by_index_rcu - find a device by its ifindex
757  *      @net: the applicable net namespace
758  *      @ifindex: index of device
759  *
760  *      Search for an interface by index. Returns %NULL if the device
761  *      is not found or a pointer to the device. The device has not
762  *      had its reference counter increased so the caller must be careful
763  *      about locking. The caller must hold RCU lock.
764  */
765 
766 struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex)
767 {
768         struct net_device *dev;
769         struct hlist_head *head = dev_index_hash(net, ifindex);
770 
771         hlist_for_each_entry_rcu(dev, head, index_hlist)
772                 if (dev->ifindex == ifindex)
773                         return dev;
774 
775         return NULL;
776 }
777 EXPORT_SYMBOL(dev_get_by_index_rcu);
778 
779 
780 /**
781  *      dev_get_by_index - find a device by its ifindex
782  *      @net: the applicable net namespace
783  *      @ifindex: index of device
784  *
785  *      Search for an interface by index. Returns NULL if the device
786  *      is not found or a pointer to the device. The device returned has
787  *      had a reference added and the pointer is safe until the user calls
788  *      dev_put to indicate they have finished with it.
789  */
790 
791 struct net_device *dev_get_by_index(struct net *net, int ifindex)
792 {
793         struct net_device *dev;
794 
795         rcu_read_lock();
796         dev = dev_get_by_index_rcu(net, ifindex);
797         if (dev)
798                 dev_hold(dev);
799         rcu_read_unlock();
800         return dev;
801 }
802 EXPORT_SYMBOL(dev_get_by_index);
803 
804 /**
805  *      netdev_get_name - get a netdevice name, knowing its ifindex.
806  *      @net: network namespace
807  *      @name: a pointer to the buffer where the name will be stored.
808  *      @ifindex: the ifindex of the interface to get the name from.
809  *
810  *      The use of raw_seqcount_begin() and cond_resched() before
811  *      retrying is required as we want to give the writers a chance
812  *      to complete when CONFIG_PREEMPT is not set.
813  */
814 int netdev_get_name(struct net *net, char *name, int ifindex)
815 {
816         struct net_device *dev;
817         unsigned int seq;
818 
819 retry:
820         seq = raw_seqcount_begin(&devnet_rename_seq);
821         rcu_read_lock();
822         dev = dev_get_by_index_rcu(net, ifindex);
823         if (!dev) {
824                 rcu_read_unlock();
825                 return -ENODEV;
826         }
827 
828         strcpy(name, dev->name);
829         rcu_read_unlock();
830         if (read_seqcount_retry(&devnet_rename_seq, seq)) {
831                 cond_resched();
832                 goto retry;
833         }
834 
835         return 0;
836 }
837 
838 /**
839  *      dev_getbyhwaddr_rcu - find a device by its hardware address
840  *      @net: the applicable net namespace
841  *      @type: media type of device
842  *      @ha: hardware address
843  *
844  *      Search for an interface by MAC address. Returns NULL if the device
845  *      is not found or a pointer to the device.
846  *      The caller must hold RCU or RTNL.
847  *      The returned device has not had its ref count increased
848  *      and the caller must therefore be careful about locking
849  *
850  */
851 
852 struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type,
853                                        const char *ha)
854 {
855         struct net_device *dev;
856 
857         for_each_netdev_rcu(net, dev)
858                 if (dev->type == type &&
859                     !memcmp(dev->dev_addr, ha, dev->addr_len))
860                         return dev;
861 
862         return NULL;
863 }
864 EXPORT_SYMBOL(dev_getbyhwaddr_rcu);
865 
866 struct net_device *__dev_getfirstbyhwtype(struct net *net, unsigned short type)
867 {
868         struct net_device *dev;
869 
870         ASSERT_RTNL();
871         for_each_netdev(net, dev)
872                 if (dev->type == type)
873                         return dev;
874 
875         return NULL;
876 }
877 EXPORT_SYMBOL(__dev_getfirstbyhwtype);
878 
879 struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type)
880 {
881         struct net_device *dev, *ret = NULL;
882 
883         rcu_read_lock();
884         for_each_netdev_rcu(net, dev)
885                 if (dev->type == type) {
886                         dev_hold(dev);
887                         ret = dev;
888                         break;
889                 }
890         rcu_read_unlock();
891         return ret;
892 }
893 EXPORT_SYMBOL(dev_getfirstbyhwtype);
894 
895 /**
896  *      dev_get_by_flags_rcu - find any device with given flags
897  *      @net: the applicable net namespace
898  *      @if_flags: IFF_* values
899  *      @mask: bitmask of bits in if_flags to check
900  *
901  *      Search for any interface with the given flags. Returns NULL if a device
902  *      is not found or a pointer to the device. Must be called inside
903  *      rcu_read_lock(), and result refcount is unchanged.
904  */
905 
906 struct net_device *dev_get_by_flags_rcu(struct net *net, unsigned short if_flags,
907                                     unsigned short mask)
908 {
909         struct net_device *dev, *ret;
910 
911         ret = NULL;
912         for_each_netdev_rcu(net, dev) {
913                 if (((dev->flags ^ if_flags) & mask) == 0) {
914                         ret = dev;
915                         break;
916                 }
917         }
918         return ret;
919 }
920 EXPORT_SYMBOL(dev_get_by_flags_rcu);
921 
922 /**
923  *      dev_valid_name - check if name is okay for network device
924  *      @name: name string
925  *
926  *      Network device names need to be valid file names to
927  *      to allow sysfs to work.  We also disallow any kind of
928  *      whitespace.
929  */
930 bool dev_valid_name(const char *name)
931 {
932         if (*name == '\0')
933                 return false;
934         if (strlen(name) >= IFNAMSIZ)
935                 return false;
936         if (!strcmp(name, ".") || !strcmp(name, ".."))
937                 return false;
938 
939         while (*name) {
940                 if (*name == '/' || isspace(*name))
941                         return false;
942                 name++;
943         }
944         return true;
945 }
946 EXPORT_SYMBOL(dev_valid_name);
947 
948 /**
949  *      __dev_alloc_name - allocate a name for a device
950  *      @net: network namespace to allocate the device name in
951  *      @name: name format string
952  *      @buf:  scratch buffer and result name string
953  *
954  *      Passed a format string - eg "lt%d" it will try and find a suitable
955  *      id. It scans list of devices to build up a free map, then chooses
956  *      the first empty slot. The caller must hold the dev_base or rtnl lock
957  *      while allocating the name and adding the device in order to avoid
958  *      duplicates.
959  *      Limited to bits_per_byte * page size devices (ie 32K on most platforms).
960  *      Returns the number of the unit assigned or a negative errno code.
961  */
962 
963 static int __dev_alloc_name(struct net *net, const char *name, char *buf)
964 {
965         int i = 0;
966         const char *p;
967         const int max_netdevices = 8*PAGE_SIZE;
968         unsigned long *inuse;
969         struct net_device *d;
970 
971         p = strnchr(name, IFNAMSIZ-1, '%');
972         if (p) {
973                 /*
974                  * Verify the string as this thing may have come from
975                  * the user.  There must be either one "%d" and no other "%"
976                  * characters.
977                  */
978                 if (p[1] != 'd' || strchr(p + 2, '%'))
979                         return -EINVAL;
980 
981                 /* Use one page as a bit array of possible slots */
982                 inuse = (unsigned long *) get_zeroed_page(GFP_ATOMIC);
983                 if (!inuse)
984                         return -ENOMEM;
985 
986                 for_each_netdev(net, d) {
987                         if (!sscanf(d->name, name, &i))
988                                 continue;
989                         if (i < 0 || i >= max_netdevices)
990                                 continue;
991 
992                         /*  avoid cases where sscanf is not exact inverse of printf */
993                         snprintf(buf, IFNAMSIZ, name, i);
994                         if (!strncmp(buf, d->name, IFNAMSIZ))
995                                 set_bit(i, inuse);
996                 }
997 
998                 i = find_first_zero_bit(inuse, max_netdevices);
999                 free_page((unsigned long) inuse);
1000         }
1001 
1002         if (buf != name)
1003                 snprintf(buf, IFNAMSIZ, name, i);
1004         if (!__dev_get_by_name(net, buf))
1005                 return i;
1006 
1007         /* It is possible to run out of possible slots
1008          * when the name is long and there isn't enough space left
1009          * for the digits, or if all bits are used.
1010          */
1011         return -ENFILE;
1012 }
1013 
1014 /**
1015  *      dev_alloc_name - allocate a name for a device
1016  *      @dev: device
1017  *      @name: name format string
1018  *
1019  *      Passed a format string - eg "lt%d" it will try and find a suitable
1020  *      id. It scans list of devices to build up a free map, then chooses
1021  *      the first empty slot. The caller must hold the dev_base or rtnl lock
1022  *      while allocating the name and adding the device in order to avoid
1023  *      duplicates.
1024  *      Limited to bits_per_byte * page size devices (ie 32K on most platforms).
1025  *      Returns the number of the unit assigned or a negative errno code.
1026  */
1027 
1028 int dev_alloc_name(struct net_device *dev, const char *name)
1029 {
1030         char buf[IFNAMSIZ];
1031         struct net *net;
1032         int ret;
1033 
1034         BUG_ON(!dev_net(dev));
1035         net = dev_net(dev);
1036         ret = __dev_alloc_name(net, name, buf);
1037         if (ret >= 0)
1038                 strlcpy(dev->name, buf, IFNAMSIZ);
1039         return ret;
1040 }
1041 EXPORT_SYMBOL(dev_alloc_name);
1042 
1043 static int dev_alloc_name_ns(struct net *net,
1044                              struct net_device *dev,
1045                              const char *name)
1046 {
1047         char buf[IFNAMSIZ];
1048         int ret;
1049 
1050         ret = __dev_alloc_name(net, name, buf);
1051         if (ret >= 0)
1052                 strlcpy(dev->name, buf, IFNAMSIZ);
1053         return ret;
1054 }
1055 
1056 static int dev_get_valid_name(struct net *net,
1057                               struct net_device *dev,
1058                               const char *name)
1059 {
1060         BUG_ON(!net);
1061 
1062         if (!dev_valid_name(name))
1063                 return -EINVAL;
1064 
1065         if (strchr(name, '%'))
1066                 return dev_alloc_name_ns(net, dev, name);
1067         else if (__dev_get_by_name(net, name))
1068                 return -EEXIST;
1069         else if (dev->name != name)
1070                 strlcpy(dev->name, name, IFNAMSIZ);
1071 
1072         return 0;
1073 }
1074 
1075 /**
1076  *      dev_change_name - change name of a device
1077  *      @dev: device
1078  *      @newname: name (or format string) must be at least IFNAMSIZ
1079  *
1080  *      Change name of a device, can pass format strings "eth%d".
1081  *      for wildcarding.
1082  */
1083 int dev_change_name(struct net_device *dev, const char *newname)
1084 {
1085         char oldname[IFNAMSIZ];
1086         int err = 0;
1087         int ret;
1088         struct net *net;
1089 
1090         ASSERT_RTNL();
1091         BUG_ON(!dev_net(dev));
1092 
1093         net = dev_net(dev);
1094         if (dev->flags & IFF_UP)
1095                 return -EBUSY;
1096 
1097         write_seqcount_begin(&devnet_rename_seq);
1098 
1099         if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
1100                 write_seqcount_end(&devnet_rename_seq);
1101                 return 0;
1102         }
1103 
1104         memcpy(oldname, dev->name, IFNAMSIZ);
1105 
1106         err = dev_get_valid_name(net, dev, newname);
1107         if (err < 0) {
1108                 write_seqcount_end(&devnet_rename_seq);
1109                 return err;
1110         }
1111 
1112 rollback:
1113         ret = device_rename(&dev->dev, dev->name);
1114         if (ret) {
1115                 memcpy(dev->name, oldname, IFNAMSIZ);
1116                 write_seqcount_end(&devnet_rename_seq);
1117                 return ret;
1118         }
1119 
1120         write_seqcount_end(&devnet_rename_seq);
1121 
1122         netdev_adjacent_rename_links(dev, oldname);
1123 
1124         write_lock_bh(&dev_base_lock);
1125         hlist_del_rcu(&dev->name_hlist);
1126         write_unlock_bh(&dev_base_lock);
1127 
1128         synchronize_rcu();
1129 
1130         write_lock_bh(&dev_base_lock);
1131         hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
1132         write_unlock_bh(&dev_base_lock);
1133 
1134         ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);
1135         ret = notifier_to_errno(ret);
1136 
1137         if (ret) {
1138                 /* err >= 0 after dev_alloc_name() or stores the first errno */
1139                 if (err >= 0) {
1140                         err = ret;
1141                         write_seqcount_begin(&devnet_rename_seq);
1142                         memcpy(dev->name, oldname, IFNAMSIZ);
1143                         memcpy(oldname, newname, IFNAMSIZ);
1144                         goto rollback;
1145                 } else {
1146                         pr_err("%s: name change rollback failed: %d\n",
1147                                dev->name, ret);
1148                 }
1149         }
1150 
1151         return err;
1152 }
1153 
1154 /**
1155  *      dev_set_alias - change ifalias of a device
1156  *      @dev: device
1157  *      @alias: name up to IFALIASZ
1158  *      @len: limit of bytes to copy from info
1159  *
1160  *      Set ifalias for a device,
1161  */
1162 int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
1163 {
1164         char *new_ifalias;
1165 
1166         ASSERT_RTNL();
1167 
1168         if (len >= IFALIASZ)
1169                 return -EINVAL;
1170 
1171         if (!len) {
1172                 kfree(dev->ifalias);
1173                 dev->ifalias = NULL;
1174                 return 0;
1175         }
1176 
1177         new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
1178         if (!new_ifalias)
1179                 return -ENOMEM;
1180         dev->ifalias = new_ifalias;
1181 
1182         strlcpy(dev->ifalias, alias, len+1);
1183         return len;
1184 }
1185 
1186 
1187 /**
1188  *      netdev_features_change - device changes features
1189  *      @dev: device to cause notification
1190  *
1191  *      Called to indicate a device has changed features.
1192  */
1193 void netdev_features_change(struct net_device *dev)
1194 {
1195         call_netdevice_notifiers(NETDEV_FEAT_CHANGE, dev);
1196 }
1197 EXPORT_SYMBOL(netdev_features_change);
1198 
1199 /**
1200  *      netdev_state_change - device changes state
1201  *      @dev: device to cause notification
1202  *
1203  *      Called to indicate a device has changed state. This function calls
1204  *      the notifier chains for netdev_chain and sends a NEWLINK message
1205  *      to the routing socket.
1206  */
1207 void netdev_state_change(struct net_device *dev)
1208 {
1209         if (dev->flags & IFF_UP) {
1210                 call_netdevice_notifiers(NETDEV_CHANGE, dev);
1211                 rtmsg_ifinfo(RTM_NEWLINK, dev, 0, GFP_KERNEL);
1212         }
1213 }
1214 EXPORT_SYMBOL(netdev_state_change);
1215 
1216 /**
1217  *      netdev_notify_peers - notify network peers about existence of @dev
1218  *      @dev: network device
1219  *
1220  * Generate traffic such that interested network peers are aware of
1221  * @dev, such as by generating a gratuitous ARP. This may be used when
1222  * a device wants to inform the rest of the network about some sort of
1223  * reconfiguration such as a failover event or virtual machine
1224  * migration.
1225  */
1226 void netdev_notify_peers(struct net_device *dev)
1227 {
1228         rtnl_lock();
1229         call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
1230         rtnl_unlock();
1231 }
1232 EXPORT_SYMBOL(netdev_notify_peers);
1233 
1234 static int __dev_open(struct net_device *dev)
1235 {
1236         const struct net_device_ops *ops = dev->netdev_ops;
1237         int ret;
1238 
1239         ASSERT_RTNL();
1240 
1241         if (!netif_device_present(dev))
1242                 return -ENODEV;
1243 
1244         /* Block netpoll from trying to do any rx path servicing.
1245          * If we don't do this there is a chance ndo_poll_controller
1246          * or ndo_poll may be running while we open the device
1247          */
1248         netpoll_rx_disable(dev);
1249 
1250         ret = call_netdevice_notifiers(NETDEV_PRE_UP, dev);
1251         ret = notifier_to_errno(ret);
1252         if (ret)
1253                 return ret;
1254 
1255         set_bit(__LINK_STATE_START, &dev->state);
1256 
1257         if (ops->ndo_validate_addr)
1258                 ret = ops->ndo_validate_addr(dev);
1259 
1260         if (!ret && ops->ndo_open)
1261                 ret = ops->ndo_open(dev);
1262 
1263         netpoll_rx_enable(dev);
1264 
1265         if (ret)
1266                 clear_bit(__LINK_STATE_START, &dev->state);
1267         else {
1268                 dev->flags |= IFF_UP;
1269                 net_dmaengine_get();
1270                 dev_set_rx_mode(dev);
1271                 dev_activate(dev);
1272                 add_device_randomness(dev->dev_addr, dev->addr_len);
1273         }
1274 
1275         return ret;
1276 }
1277 
1278 /**
1279  *      dev_open        - prepare an interface for use.
1280  *      @dev:   device to open
1281  *
1282  *      Takes a device from down to up state. The device's private open
1283  *      function is invoked and then the multicast lists are loaded. Finally
1284  *      the device is moved into the up state and a %NETDEV_UP message is
1285  *      sent to the netdev notifier chain.
1286  *
1287  *      Calling this function on an active interface is a nop. On a failure
1288  *      a negative errno code is returned.
1289  */
1290 int dev_open(struct net_device *dev)
1291 {
1292         int ret;
1293 
1294         if (dev->flags & IFF_UP)
1295                 return 0;
1296 
1297         ret = __dev_open(dev);
1298         if (ret < 0)
1299                 return ret;
1300 
1301         rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING, GFP_KERNEL);
1302         call_netdevice_notifiers(NETDEV_UP, dev);
1303 
1304         return ret;
1305 }
1306 EXPORT_SYMBOL(dev_open);
1307 
1308 static int __dev_close_many(struct list_head *head)
1309 {
1310         struct net_device *dev;
1311 
1312         ASSERT_RTNL();
1313         might_sleep();
1314 
1315         list_for_each_entry(dev, head, close_list) {
1316                 call_netdevice_notifiers(NETDEV_GOING_DOWN, dev);
1317 
1318                 clear_bit(__LINK_STATE_START, &dev->state);
1319 
1320                 /* Synchronize to scheduled poll. We cannot touch poll list, it
1321                  * can be even on different cpu. So just clear netif_running().
1322                  *
1323                  * dev->stop() will invoke napi_disable() on all of it's
1324                  * napi_struct instances on this device.
1325                  */
1326                 smp_mb__after_clear_bit(); /* Commit netif_running(). */
1327         }
1328 
1329         dev_deactivate_many(head);
1330 
1331         list_for_each_entry(dev, head, close_list) {
1332                 const struct net_device_ops *ops = dev->netdev_ops;
1333 
1334                 /*
1335                  *      Call the device specific close. This cannot fail.
1336                  *      Only if device is UP
1337                  *
1338                  *      We allow it to be called even after a DETACH hot-plug
1339                  *      event.
1340                  */
1341                 if (ops->ndo_stop)
1342                         ops->ndo_stop(dev);
1343 
1344                 dev->flags &= ~IFF_UP;
1345                 net_dmaengine_put();
1346         }
1347 
1348         return 0;
1349 }
1350 
1351 static int __dev_close(struct net_device *dev)
1352 {
1353         int retval;
1354         LIST_HEAD(single);
1355 
1356         /* Temporarily disable netpoll until the interface is down */
1357         netpoll_rx_disable(dev);
1358 
1359         list_add(&dev->close_list, &single);
1360         retval = __dev_close_many(&single);
1361         list_del(&single);
1362 
1363         netpoll_rx_enable(dev);
1364         return retval;
1365 }
1366 
1367 static int dev_close_many(struct list_head *head)
1368 {
1369         struct net_device *dev, *tmp;
1370 
1371         /* Remove the devices that don't need to be closed */
1372         list_for_each_entry_safe(dev, tmp, head, close_list)
1373                 if (!(dev->flags & IFF_UP))
1374                         list_del_init(&dev->close_list);
1375 
1376         __dev_close_many(head);
1377 
1378         list_for_each_entry_safe(dev, tmp, head, close_list) {
1379                 rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING, GFP_KERNEL);
1380                 call_netdevice_notifiers(NETDEV_DOWN, dev);
1381                 list_del_init(&dev->close_list);
1382         }
1383 
1384         return 0;
1385 }
1386 
1387 /**
1388  *      dev_close - shutdown an interface.
1389  *      @dev: device to shutdown
1390  *
1391  *      This function moves an active device into down state. A
1392  *      %NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device
1393  *      is then deactivated and finally a %NETDEV_DOWN is sent to the notifier
1394  *      chain.
1395  */
1396 int dev_close(struct net_device *dev)
1397 {
1398         if (dev->flags & IFF_UP) {
1399                 LIST_HEAD(single);
1400 
1401                 /* Block netpoll rx while the interface is going down */
1402                 netpoll_rx_disable(dev);
1403 
1404                 list_add(&dev->close_list, &single);
1405                 dev_close_many(&single);
1406                 list_del(&single);
1407 
1408                 netpoll_rx_enable(dev);
1409         }
1410         return 0;
1411 }
1412 EXPORT_SYMBOL(dev_close);
1413 
1414 
1415 /**
1416  *      dev_disable_lro - disable Large Receive Offload on a device
1417  *      @dev: device
1418  *
1419  *      Disable Large Receive Offload (LRO) on a net device.  Must be
1420  *      called under RTNL.  This is needed if received packets may be
1421  *      forwarded to another interface.
1422  */
1423 void dev_disable_lro(struct net_device *dev)
1424 {
1425         /*
1426          * If we're trying to disable lro on a vlan device
1427          * use the underlying physical device instead
1428          */
1429         if (is_vlan_dev(dev))
1430                 dev = vlan_dev_real_dev(dev);
1431 
1432         /* the same for macvlan devices */
1433         if (netif_is_macvlan(dev))
1434                 dev = macvlan_dev_real_dev(dev);
1435 
1436         dev->wanted_features &= ~NETIF_F_LRO;
1437         netdev_update_features(dev);
1438 
1439         if (unlikely(dev->features & NETIF_F_LRO))
1440                 netdev_WARN(dev, "failed to disable LRO!\n");
1441 }
1442 EXPORT_SYMBOL(dev_disable_lro);
1443 
1444 static int call_netdevice_notifier(struct notifier_block *nb, unsigned long val,
1445                                    struct net_device *dev)
1446 {
1447         struct netdev_notifier_info info;
1448 
1449         netdev_notifier_info_init(&info, dev);
1450         return nb->notifier_call(nb, val, &info);
1451 }
1452 
1453 static int dev_boot_phase = 1;
1454 
1455 /**
1456  *      register_netdevice_notifier - register a network notifier block
1457  *      @nb: notifier
1458  *
1459  *      Register a notifier to be called when network device events occur.
1460  *      The notifier passed is linked into the kernel structures and must
1461  *      not be reused until it has been unregistered. A negative errno code
1462  *      is returned on a failure.
1463  *
1464  *      When registered all registration and up events are replayed
1465  *      to the new notifier to allow device to have a race free
1466  *      view of the network device list.
1467  */
1468 
1469 int register_netdevice_notifier(struct notifier_block *nb)
1470 {
1471         struct net_device *dev;
1472         struct net_device *last;
1473         struct net *net;
1474         int err;
1475 
1476         rtnl_lock();
1477         err = raw_notifier_chain_register(&netdev_chain, nb);
1478         if (err)
1479                 goto unlock;
1480         if (dev_boot_phase)
1481                 goto unlock;
1482         for_each_net(net) {
1483                 for_each_netdev(net, dev) {
1484                         err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
1485                         err = notifier_to_errno(err);
1486                         if (err)
1487                                 goto rollback;
1488 
1489                         if (!(dev->flags & IFF_UP))
1490                                 continue;
1491 
1492                         call_netdevice_notifier(nb, NETDEV_UP, dev);
1493                 }
1494         }
1495 
1496 unlock:
1497         rtnl_unlock();
1498         return err;
1499 
1500 rollback:
1501         last = dev;
1502         for_each_net(net) {
1503                 for_each_netdev(net, dev) {
1504                         if (dev == last)
1505                                 goto outroll;
1506 
1507                         if (dev->flags & IFF_UP) {
1508                                 call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
1509                                                         dev);
1510                                 call_netdevice_notifier(nb, NETDEV_DOWN, dev);
1511                         }
1512                         call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
1513                 }
1514         }
1515 
1516 outroll:
1517         raw_notifier_chain_unregister(&netdev_chain, nb);
1518         goto unlock;
1519 }
1520 EXPORT_SYMBOL(register_netdevice_notifier);
1521 
1522 /**
1523  *      unregister_netdevice_notifier - unregister a network notifier block
1524  *      @nb: notifier
1525  *
1526  *      Unregister a notifier previously registered by
1527  *      register_netdevice_notifier(). The notifier is unlinked into the
1528  *      kernel structures and may then be reused. A negative errno code
1529  *      is returned on a failure.
1530  *
1531  *      After unregistering unregister and down device events are synthesized
1532  *      for all devices on the device list to the removed notifier to remove
1533  *      the need for special case cleanup code.
1534  */
1535 
1536 int unregister_netdevice_notifier(struct notifier_block *nb)
1537 {
1538         struct net_device *dev;
1539         struct net *net;
1540         int err;
1541 
1542         rtnl_lock();
1543         err = raw_notifier_chain_unregister(&netdev_chain, nb);
1544         if (err)
1545                 goto unlock;
1546 
1547         for_each_net(net) {
1548                 for_each_netdev(net, dev) {
1549                         if (dev->flags & IFF_UP) {
1550                                 call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
1551                                                         dev);
1552                                 call_netdevice_notifier(nb, NETDEV_DOWN, dev);
1553                         }
1554                         call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
1555                 }
1556         }
1557 unlock:
1558         rtnl_unlock();
1559         return err;
1560 }
1561 EXPORT_SYMBOL(unregister_netdevice_notifier);
1562 
1563 /**
1564  *      call_netdevice_notifiers_info - call all network notifier blocks
1565  *      @val: value passed unmodified to notifier function
1566  *      @dev: net_device pointer passed unmodified to notifier function
1567  *      @info: notifier information data
1568  *
1569  *      Call all network notifier blocks.  Parameters and return value
1570  *      are as for raw_notifier_call_chain().
1571  */
1572 
1573 static int call_netdevice_notifiers_info(unsigned long val,
1574                                          struct net_device *dev,
1575                                          struct netdev_notifier_info *info)
1576 {
1577         ASSERT_RTNL();
1578         netdev_notifier_info_init(info, dev);
1579         return raw_notifier_call_chain(&netdev_chain, val, info);
1580 }
1581 
1582 /**
1583  *      call_netdevice_notifiers - call all network notifier blocks
1584  *      @val: value passed unmodified to notifier function
1585  *      @dev: net_device pointer passed unmodified to notifier function
1586  *
1587  *      Call all network notifier blocks.  Parameters and return value
1588  *      are as for raw_notifier_call_chain().
1589  */
1590 
1591 int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
1592 {
1593         struct netdev_notifier_info info;
1594 
1595         return call_netdevice_notifiers_info(val, dev, &info);
1596 }
1597 EXPORT_SYMBOL(call_netdevice_notifiers);
1598 
1599 static struct static_key netstamp_needed __read_mostly;
1600 #ifdef HAVE_JUMP_LABEL
1601 /* We are not allowed to call static_key_slow_dec() from irq context
1602  * If net_disable_timestamp() is called from irq context, defer the
1603  * static_key_slow_dec() calls.
1604  */
1605 static atomic_t netstamp_needed_deferred;
1606 #endif
1607 
1608 void net_enable_timestamp(void)
1609 {
1610 #ifdef HAVE_JUMP_LABEL
1611         int deferred = atomic_xchg(&netstamp_needed_deferred, 0);
1612 
1613         if (deferred) {
1614                 while (--deferred)
1615                         static_key_slow_dec(&netstamp_needed);
1616                 return;
1617         }
1618 #endif
1619         static_key_slow_inc(&netstamp_needed);
1620 }
1621 EXPORT_SYMBOL(net_enable_timestamp);
1622 
1623 void net_disable_timestamp(void)
1624 {
1625 #ifdef HAVE_JUMP_LABEL
1626         if (in_interrupt()) {
1627                 atomic_inc(&netstamp_needed_deferred);
1628                 return;
1629         }
1630 #endif
1631         static_key_slow_dec(&netstamp_needed);
1632 }
1633 EXPORT_SYMBOL(net_disable_timestamp);
1634 
1635 static inline void net_timestamp_set(struct sk_buff *skb)
1636 {
1637         skb->tstamp.tv64 = 0;
1638         if (static_key_false(&netstamp_needed))
1639                 __net_timestamp(skb);
1640 }
1641 
1642 #define net_timestamp_check(COND, SKB)                  \
1643         if (static_key_false(&netstamp_needed)) {               \
1644                 if ((COND) && !(SKB)->tstamp.tv64)      \
1645                         __net_timestamp(SKB);           \
1646         }                                               \
1647 
1648 static inline bool is_skb_forwardable(struct net_device *dev,
1649                                       struct sk_buff *skb)
1650 {
1651         unsigned int len;
1652 
1653         if (!(dev->flags & IFF_UP))
1654                 return false;
1655 
1656         len = dev->mtu + dev->hard_header_len + VLAN_HLEN;
1657         if (skb->len <= len)
1658                 return true;
1659 
1660         /* if TSO is enabled, we don't care about the length as the packet
1661          * could be forwarded without being segmented before
1662          */
1663         if (skb_is_gso(skb))
1664                 return true;
1665 
1666         return false;
1667 }
1668 
1669 /**
1670  * dev_forward_skb - loopback an skb to another netif
1671  *
1672  * @dev: destination network device
1673  * @skb: buffer to forward
1674  *
1675  * return values:
1676  *      NET_RX_SUCCESS  (no congestion)
1677  *      NET_RX_DROP     (packet was dropped, but freed)
1678  *
1679  * dev_forward_skb can be used for injecting an skb from the
1680  * start_xmit function of one device into the receive queue
1681  * of another device.
1682  *
1683  * The receiving device may be in another namespace, so
1684  * we have to clear all information in the skb that could
1685  * impact namespace isolation.
1686  */
1687 int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
1688 {
1689         if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
1690                 if (skb_copy_ubufs(skb, GFP_ATOMIC)) {
1691                         atomic_long_inc(&dev->rx_dropped);
1692                         kfree_skb(skb);
1693                         return NET_RX_DROP;
1694                 }
1695         }
1696 
1697         if (unlikely(!is_skb_forwardable(dev, skb))) {
1698                 atomic_long_inc(&dev->rx_dropped);
1699                 kfree_skb(skb);
1700                 return NET_RX_DROP;
1701         }
1702 
1703         skb_scrub_packet(skb, true);
1704         skb->protocol = eth_type_trans(skb, dev);
1705 
1706         return netif_rx_internal(skb);
1707 }
1708 EXPORT_SYMBOL_GPL(dev_forward_skb);
1709 
1710 static inline int deliver_skb(struct sk_buff *skb,
1711                               struct packet_type *pt_prev,
1712                               struct net_device *orig_dev)
1713 {
1714         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
1715                 return -ENOMEM;
1716         atomic_inc(&skb->users);
1717         return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
1718 }
1719 
1720 static inline bool skb_loop_sk(struct packet_type *ptype, struct sk_buff *skb)
1721 {
1722         if (!ptype->af_packet_priv || !skb->sk)
1723                 return false;
1724 
1725         if (ptype->id_match)
1726                 return ptype->id_match(ptype, skb->sk);
1727         else if ((struct sock *)ptype->af_packet_priv == skb->sk)
1728                 return true;
1729 
1730         return false;
1731 }
1732 
1733 /*
1734  *      Support routine. Sends outgoing frames to any network
1735  *      taps currently in use.
1736  */
1737 
1738 static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
1739 {
1740         struct packet_type *ptype;
1741         struct sk_buff *skb2 = NULL;
1742         struct packet_type *pt_prev = NULL;
1743 
1744         rcu_read_lock();
1745         list_for_each_entry_rcu(ptype, &ptype_all, list) {
1746                 /* Never send packets back to the socket
1747                  * they originated from - MvS (miquels@drinkel.ow.org)
1748                  */
1749                 if ((ptype->dev == dev || !ptype->dev) &&
1750                     (!skb_loop_sk(ptype, skb))) {
1751                         if (pt_prev) {
1752                                 deliver_skb(skb2, pt_prev, skb->dev);
1753                                 pt_prev = ptype;
1754                                 continue;
1755                         }
1756 
1757                         skb2 = skb_clone(skb, GFP_ATOMIC);
1758                         if (!skb2)
1759                                 break;
1760 
1761                         net_timestamp_set(skb2);
1762 
1763                         /* skb->nh should be correctly
1764                            set by sender, so that the second statement is
1765                            just protection against buggy protocols.
1766                          */
1767                         skb_reset_mac_header(skb2);
1768 
1769                         if (skb_network_header(skb2) < skb2->data ||
1770                             skb_network_header(skb2) > skb_tail_pointer(skb2)) {
1771                                 net_crit_ratelimited("protocol %04x is buggy, dev %s\n",
1772                                                      ntohs(skb2->protocol),
1773                                                      dev->name);
1774                                 skb_reset_network_header(skb2);
1775                         }
1776 
1777                         skb2->transport_header = skb2->network_header;
1778                         skb2->pkt_type = PACKET_OUTGOING;
1779                         pt_prev = ptype;
1780                 }
1781         }
1782         if (pt_prev)
1783                 pt_prev->func(skb2, skb->dev, pt_prev, skb->dev);
1784         rcu_read_unlock();
1785 }
1786 
1787 /**
1788  * netif_setup_tc - Handle tc mappings on real_num_tx_queues change
1789  * @dev: Network device
1790  * @txq: number of queues available
1791  *
1792  * If real_num_tx_queues is changed the tc mappings may no longer be
1793  * valid. To resolve this verify the tc mapping remains valid and if
1794  * not NULL the mapping. With no priorities mapping to this
1795  * offset/count pair it will no longer be used. In the worst case TC0
1796  * is invalid nothing can be done so disable priority mappings. If is
1797  * expected that drivers will fix this mapping if they can before
1798  * calling netif_set_real_num_tx_queues.
1799  */
1800 static void netif_setup_tc(struct net_device *dev, unsigned int txq)
1801 {
1802         int i;
1803         struct netdev_tc_txq *tc = &dev->tc_to_txq[0];
1804 
1805         /* If TC0 is invalidated disable TC mapping */
1806         if (tc->offset + tc->count > txq) {
1807                 pr_warn("Number of in use tx queues changed invalidating tc mappings. Priority traffic classification disabled!\n");
1808                 dev->num_tc = 0;
1809                 return;
1810         }
1811 
1812         /* Invalidated prio to tc mappings set to TC0 */
1813         for (i = 1; i < TC_BITMASK + 1; i++) {
1814                 int q = netdev_get_prio_tc_map(dev, i);
1815 
1816                 tc = &dev->tc_to_txq[q];
1817                 if (tc->offset + tc->count > txq) {
1818                         pr_warn("Number of in use tx queues changed. Priority %i to tc mapping %i is no longer valid. Setting map to 0\n",
1819                                 i, q);
1820                         netdev_set_prio_tc_map(dev, i, 0);
1821                 }
1822         }
1823 }
1824 
1825 #ifdef CONFIG_XPS
1826 static DEFINE_MUTEX(xps_map_mutex);
1827 #define xmap_dereference(P)             \
1828         rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex))
1829 
1830 static struct xps_map *remove_xps_queue(struct xps_dev_maps *dev_maps,
1831                                         int cpu, u16 index)
1832 {
1833         struct xps_map *map = NULL;
1834         int pos;
1835 
1836         if (dev_maps)
1837                 map = xmap_dereference(dev_maps->cpu_map[cpu]);
1838 
1839         for (pos = 0; map && pos < map->len; pos++) {
1840                 if (map->queues[pos] == index) {
1841                         if (map->len > 1) {
1842                                 map->queues[pos] = map->queues[--map->len];
1843                         } else {
1844                                 RCU_INIT_POINTER(dev_maps->cpu_map[cpu], NULL);
1845                                 kfree_rcu(map, rcu);
1846                                 map = NULL;
1847                         }
1848                         break;
1849                 }
1850         }
1851 
1852         return map;
1853 }
1854 
1855 static void netif_reset_xps_queues_gt(struct net_device *dev, u16 index)
1856 {
1857         struct xps_dev_maps *dev_maps;
1858         int cpu, i;
1859         bool active = false;
1860 
1861         mutex_lock(&xps_map_mutex);
1862         dev_maps = xmap_dereference(dev->xps_maps);
1863 
1864         if (!dev_maps)
1865                 goto out_no_maps;
1866 
1867         for_each_possible_cpu(cpu) {
1868                 for (i = index; i < dev->num_tx_queues; i++) {
1869                         if (!remove_xps_queue(dev_maps, cpu, i))
1870                                 break;
1871                 }
1872                 if (i == dev->num_tx_queues)
1873                         active = true;
1874         }
1875 
1876         if (!active) {
1877                 RCU_INIT_POINTER(dev->xps_maps, NULL);
1878                 kfree_rcu(dev_maps, rcu);
1879         }
1880 
1881         for (i = index; i < dev->num_tx_queues; i++)
1882                 netdev_queue_numa_node_write(netdev_get_tx_queue(dev, i),
1883                                              NUMA_NO_NODE);
1884 
1885 out_no_maps:
1886         mutex_unlock(&xps_map_mutex);
1887 }
1888 
1889 static struct xps_map *expand_xps_map(struct xps_map *map,
1890                                       int cpu, u16 index)
1891 {
1892         struct xps_map *new_map;
1893         int alloc_len = XPS_MIN_MAP_ALLOC;
1894         int i, pos;
1895 
1896         for (pos = 0; map && pos < map->len; pos++) {
1897                 if (map->queues[pos] != index)
1898                         continue;
1899                 return map;
1900         }
1901 
1902         /* Need to add queue to this CPU's existing map */
1903         if (map) {
1904                 if (pos < map->alloc_len)
1905                         return map;
1906 
1907                 alloc_len = map->alloc_len * 2;
1908         }
1909 
1910         /* Need to allocate new map to store queue on this CPU's map */
1911         new_map = kzalloc_node(XPS_MAP_SIZE(alloc_len), GFP_KERNEL,
1912                                cpu_to_node(cpu));
1913         if (!new_map)
1914                 return NULL;
1915 
1916         for (i = 0; i < pos; i++)
1917                 new_map->queues[i] = map->queues[i];
1918         new_map->alloc_len = alloc_len;
1919         new_map->len = pos;
1920 
1921         return new_map;
1922 }
1923 
1924 int netif_set_xps_queue(struct net_device *dev, const struct cpumask *mask,
1925                         u16 index)
1926 {
1927         struct xps_dev_maps *dev_maps, *new_dev_maps = NULL;
1928         struct xps_map *map, *new_map;
1929         int maps_sz = max_t(unsigned int, XPS_DEV_MAPS_SIZE, L1_CACHE_BYTES);
1930         int cpu, numa_node_id = -2;
1931         bool active = false;
1932 
1933         mutex_lock(&xps_map_mutex);
1934 
1935         dev_maps = xmap_dereference(dev->xps_maps);
1936 
1937         /* allocate memory for queue storage */
1938         for_each_online_cpu(cpu) {
1939                 if (!cpumask_test_cpu(cpu, mask))
1940                         continue;
1941 
1942                 if (!new_dev_maps)
1943                         new_dev_maps = kzalloc(maps_sz, GFP_KERNEL);
1944                 if (!new_dev_maps) {
1945                         mutex_unlock(&xps_map_mutex);
1946                         return -ENOMEM;
1947                 }
1948 
1949                 map = dev_maps ? xmap_dereference(dev_maps->cpu_map[cpu]) :
1950                                  NULL;
1951 
1952                 map = expand_xps_map(map, cpu, index);
1953                 if (!map)
1954                         goto error;
1955 
1956                 RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], map);
1957         }
1958 
1959         if (!new_dev_maps)
1960                 goto out_no_new_maps;
1961 
1962         for_each_possible_cpu(cpu) {
1963                 if (cpumask_test_cpu(cpu, mask) && cpu_online(cpu)) {
1964                         /* add queue to CPU maps */
1965                         int pos = 0;
1966 
1967                         map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
1968                         while ((pos < map->len) && (map->queues[pos] != index))
1969                                 pos++;
1970 
1971                         if (pos == map->len)
1972                                 map->queues[map->len++] = index;
1973 #ifdef CONFIG_NUMA
1974                         if (numa_node_id == -2)
1975                                 numa_node_id = cpu_to_node(cpu);
1976                         else if (numa_node_id != cpu_to_node(cpu))
1977                                 numa_node_id = -1;
1978 #endif
1979                 } else if (dev_maps) {
1980                         /* fill in the new device map from the old device map */
1981                         map = xmap_dereference(dev_maps->cpu_map[cpu]);
1982                         RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], map);
1983                 }
1984 
1985         }
1986 
1987         rcu_assign_pointer(dev->xps_maps, new_dev_maps);
1988 
1989         /* Cleanup old maps */
1990         if (dev_maps) {
1991                 for_each_possible_cpu(cpu) {
1992                         new_map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
1993                         map = xmap_dereference(dev_maps->cpu_map[cpu]);
1994                         if (map && map != new_map)
1995                                 kfree_rcu(map, rcu);
1996                 }
1997 
1998                 kfree_rcu(dev_maps, rcu);
1999         }
2000 
2001         dev_maps = new_dev_maps;
2002         active = true;
2003 
2004 out_no_new_maps:
2005         /* update Tx queue numa node */
2006         netdev_queue_numa_node_write(netdev_get_tx_queue(dev, index),
2007                                      (numa_node_id >= 0) ? numa_node_id :
2008                                      NUMA_NO_NODE);
2009 
2010         if (!dev_maps)
2011                 goto out_no_maps;
2012 
2013         /* removes queue from unused CPUs */
2014         for_each_possible_cpu(cpu) {
2015                 if (cpumask_test_cpu(cpu, mask) && cpu_online(cpu))
2016                         continue;
2017 
2018                 if (remove_xps_queue(dev_maps, cpu, index))
2019                         active = true;
2020         }
2021 
2022         /* free map if not active */
2023         if (!active) {
2024                 RCU_INIT_POINTER(dev->xps_maps, NULL);
2025                 kfree_rcu(dev_maps, rcu);
2026         }
2027 
2028 out_no_maps:
2029         mutex_unlock(&xps_map_mutex);
2030 
2031         return 0;
2032 error:
2033         /* remove any maps that we added */
2034         for_each_possible_cpu(cpu) {
2035                 new_map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
2036                 map = dev_maps ? xmap_dereference(dev_maps->cpu_map[cpu]) :
2037                                  NULL;
2038                 if (new_map && new_map != map)
2039                         kfree(new_map);
2040         }
2041 
2042         mutex_unlock(&xps_map_mutex);
2043 
2044         kfree(new_dev_maps);
2045         return -ENOMEM;
2046 }
2047 EXPORT_SYMBOL(netif_set_xps_queue);
2048 
2049 #endif
2050 /*
2051  * Routine to help set real_num_tx_queues. To avoid skbs mapped to queues
2052  * greater then real_num_tx_queues stale skbs on the qdisc must be flushed.
2053  */
2054 int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
2055 {
2056         int rc;
2057 
2058         if (txq < 1 || txq > dev->num_tx_queues)
2059                 return -EINVAL;
2060 
2061         if (dev->reg_state == NETREG_REGISTERED ||
2062             dev->reg_state == NETREG_UNREGISTERING) {
2063                 ASSERT_RTNL();
2064 
2065                 rc = netdev_queue_update_kobjects(dev, dev->real_num_tx_queues,
2066                                                   txq);
2067                 if (rc)
2068                         return rc;
2069 
2070                 if (dev->num_tc)
2071                         netif_setup_tc(dev, txq);
2072 
2073                 if (txq < dev->real_num_tx_queues) {
2074                         qdisc_reset_all_tx_gt(dev, txq);
2075 #ifdef CONFIG_XPS
2076                         netif_reset_xps_queues_gt(dev, txq);
2077 #endif
2078                 }
2079         }
2080 
2081         dev->real_num_tx_queues = txq;
2082         return 0;
2083 }
2084 EXPORT_SYMBOL(netif_set_real_num_tx_queues);
2085 
2086 #ifdef CONFIG_SYSFS
2087 /**
2088  *      netif_set_real_num_rx_queues - set actual number of RX queues used
2089  *      @dev: Network device
2090  *      @rxq: Actual number of RX queues
2091  *
2092  *      This must be called either with the rtnl_lock held or before
2093  *      registration of the net device.  Returns 0 on success, or a
2094  *      negative error code.  If called before registration, it always
2095  *      succeeds.
2096  */
2097 int netif_set_real_num_rx_queues(struct net_device *dev, unsigned int rxq)
2098 {
2099         int rc;
2100 
2101         if (rxq < 1 || rxq > dev->num_rx_queues)
2102                 return -EINVAL;
2103 
2104         if (dev->reg_state == NETREG_REGISTERED) {
2105                 ASSERT_RTNL();
2106 
2107                 rc = net_rx_queue_update_kobjects(dev, dev->real_num_rx_queues,
2108                                                   rxq);
2109                 if (rc)
2110                         return rc;
2111         }
2112 
2113         dev->real_num_rx_queues = rxq;
2114         return 0;
2115 }
2116 EXPORT_SYMBOL(netif_set_real_num_rx_queues);
2117 #endif
2118 
2119 /**
2120  * netif_get_num_default_rss_queues - default number of RSS queues
2121  *
2122  * This routine should set an upper limit on the number of RSS queues
2123  * used by default by multiqueue devices.
2124  */
2125 int netif_get_num_default_rss_queues(void)
2126 {
2127         return min_t(int, DEFAULT_MAX_NUM_RSS_QUEUES, num_online_cpus());
2128 }
2129 EXPORT_SYMBOL(netif_get_num_default_rss_queues);
2130 
2131 static inline void __netif_reschedule(struct Qdisc *q)
2132 {
2133         struct softnet_data *sd;
2134         unsigned long flags;
2135 
2136         local_irq_save(flags);
2137         sd = &__get_cpu_var(softnet_data);
2138         q->next_sched = NULL;
2139         *sd->output_queue_tailp = q;
2140         sd->output_queue_tailp = &q->next_sched;
2141         raise_softirq_irqoff(NET_TX_SOFTIRQ);
2142         local_irq_restore(flags);
2143 }
2144 
2145 void __netif_schedule(struct Qdisc *q)
2146 {
2147         if (!test_and_set_bit(__QDISC_STATE_SCHED, &q->state))
2148                 __netif_reschedule(q);
2149 }
2150 EXPORT_SYMBOL(__netif_schedule);
2151 
2152 struct dev_kfree_skb_cb {
2153         enum skb_free_reason reason;
2154 };
2155 
2156 static struct dev_kfree_skb_cb *get_kfree_skb_cb(const struct sk_buff *skb)
2157 {
2158         return (struct dev_kfree_skb_cb *)skb->cb;
2159 }
2160 
2161 void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
2162 {
2163         unsigned long flags;
2164 
2165         if (likely(atomic_read(&skb->users) == 1)) {
2166                 smp_rmb();
2167                 atomic_set(&skb->users, 0);
2168         } else if (likely(!atomic_dec_and_test(&skb->users))) {
2169                 return;
2170         }
2171         get_kfree_skb_cb(skb)->reason = reason;
2172         local_irq_save(flags);
2173         skb->next = __this_cpu_read(softnet_data.completion_queue);
2174         __this_cpu_write(softnet_data.completion_queue, skb);
2175         raise_softirq_irqoff(NET_TX_SOFTIRQ);
2176         local_irq_restore(flags);
2177 }
2178 EXPORT_SYMBOL(__dev_kfree_skb_irq);
2179 
2180 void __dev_kfree_skb_any(struct sk_buff *skb, enum skb_free_reason reason)
2181 {
2182         if (in_irq() || irqs_disabled())
2183                 __dev_kfree_skb_irq(skb, reason);
2184         else
2185                 dev_kfree_skb(skb);
2186 }
2187 EXPORT_SYMBOL(__dev_kfree_skb_any);
2188 
2189 
2190 /**
2191  * netif_device_detach - mark device as removed
2192  * @dev: network device
2193  *
2194  * Mark device as removed from system and therefore no longer available.
2195  */
2196 void netif_device_detach(struct net_device *dev)
2197 {
2198         if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
2199             netif_running(dev)) {
2200                 netif_tx_stop_all_queues(dev);
2201         }
2202 }
2203 EXPORT_SYMBOL(netif_device_detach);
2204 
2205 /**
2206  * netif_device_attach - mark device as attached
2207  * @dev: network device
2208  *
2209  * Mark device as attached from system and restart if needed.
2210  */
2211 void netif_device_attach(struct net_device *dev)
2212 {
2213         if (!test_and_set_bit(__LINK_STATE_PRESENT, &dev->state) &&
2214             netif_running(dev)) {
2215                 netif_tx_wake_all_queues(dev);
2216                 __netdev_watchdog_up(dev);
2217         }
2218 }
2219 EXPORT_SYMBOL(netif_device_attach);
2220 
2221 static void skb_warn_bad_offload(const struct sk_buff *skb)
2222 {
2223         static const netdev_features_t null_features = 0;
2224         struct net_device *dev = skb->dev;
2225         const char *driver = "";
2226 
2227         if (!net_ratelimit())
2228                 return;
2229 
2230         if (dev && dev->dev.parent)
2231                 driver = dev_driver_string(dev->dev.parent);
2232 
2233         WARN(1, "%s: caps=(%pNF, %pNF) len=%d data_len=%d gso_size=%d "
2234              "gso_type=%d ip_summed=%d\n",
2235              driver, dev ? &dev->features : &null_features,
2236              skb->sk ? &skb->sk->sk_route_caps : &null_features,
2237              skb->len, skb->data_len, skb_shinfo(skb)->gso_size,
2238              skb_shinfo(skb)->gso_type, skb->ip_summed);
2239 }
2240 
2241 /*
2242  * Invalidate hardware checksum when packet is to be mangled, and
2243  * complete checksum manually on outgoing path.
2244  */
2245 int skb_checksum_help(struct sk_buff *skb)
2246 {
2247         __wsum csum;
2248         int ret = 0, offset;
2249 
2250         if (skb->ip_summed == CHECKSUM_COMPLETE)
2251                 goto out_set_summed;
2252 
2253         if (unlikely(skb_shinfo(skb)->gso_size)) {
2254                 skb_warn_bad_offload(skb);
2255                 return -EINVAL;
2256         }
2257 
2258         /* Before computing a checksum, we should make sure no frag could
2259          * be modified by an external entity : checksum could be wrong.
2260          */
2261         if (skb_has_shared_frag(skb)) {
2262                 ret = __skb_linearize(skb);
2263                 if (ret)
2264                         goto out;
2265         }
2266 
2267         offset = skb_checksum_start_offset(skb);
2268         BUG_ON(offset >= skb_headlen(skb));
2269         csum = skb_checksum(skb, offset, skb->len - offset, 0);
2270 
2271         offset += skb->csum_offset;
2272         BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb));
2273 
2274         if (skb_cloned(skb) &&
2275             !skb_clone_writable(skb, offset + sizeof(__sum16))) {
2276                 ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2277                 if (ret)
2278                         goto out;
2279         }
2280 
2281         *(__sum16 *)(skb->data + offset) = csum_fold(csum);
2282 out_set_summed:
2283         skb->ip_summed = CHECKSUM_NONE;
2284 out:
2285         return ret;
2286 }
2287 EXPORT_SYMBOL(skb_checksum_help);
2288 
2289 __be16 skb_network_protocol(struct sk_buff *skb, int *depth)
2290 {
2291         __be16 type = skb->protocol;
2292         int vlan_depth = ETH_HLEN;
2293 
2294         /* Tunnel gso handlers can set protocol to ethernet. */
2295         if (type == htons(ETH_P_TEB)) {
2296                 struct ethhdr *eth;
2297 
2298                 if (unlikely(!pskb_may_pull(skb, sizeof(struct ethhdr))))
2299                         return 0;
2300 
2301                 eth = (struct ethhdr *)skb_mac_header(skb);
2302                 type = eth->h_proto;
2303         }
2304 
2305         while (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {
2306                 struct vlan_hdr *vh;
2307 
2308                 if (unlikely(!pskb_may_pull(skb, vlan_depth + VLAN_HLEN)))
2309                         return 0;
2310 
2311                 vh = (struct vlan_hdr *)(skb->data + vlan_depth);
2312                 type = vh->h_vlan_encapsulated_proto;
2313                 vlan_depth += VLAN_HLEN;
2314         }
2315 
2316         *depth = vlan_depth;
2317 
2318         return type;
2319 }
2320 
2321 /**
2322  *      skb_mac_gso_segment - mac layer segmentation handler.
2323  *      @skb: buffer to segment
2324  *      @features: features for the output path (see dev->features)
2325  */
2326 struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,
2327                                     netdev_features_t features)
2328 {
2329         struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
2330         struct packet_offload *ptype;
2331         int vlan_depth = skb->mac_len;
2332         __be16 type = skb_network_protocol(skb, &vlan_depth);
2333 
2334         if (unlikely(!type))
2335                 return ERR_PTR(-EINVAL);
2336 
2337         __skb_pull(skb, vlan_depth);
2338 
2339         rcu_read_lock();
2340         list_for_each_entry_rcu(ptype, &offload_base, list) {
2341                 if (ptype->type == type && ptype->callbacks.gso_segment) {
2342                         if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
2343                                 int err;
2344 
2345                                 err = ptype->callbacks.gso_send_check(skb);
2346                                 segs = ERR_PTR(err);
2347                                 if (err || skb_gso_ok(skb, features))
2348                                         break;
2349                                 __skb_push(skb, (skb->data -
2350                                                  skb_network_header(skb)));
2351                         }
2352                         segs = ptype->callbacks.gso_segment(skb, features);
2353                         break;
2354                 }
2355         }
2356         rcu_read_unlock();
2357 
2358         __skb_push(skb, skb->data - skb_mac_header(skb));
2359 
2360         return segs;
2361 }
2362 EXPORT_SYMBOL(skb_mac_gso_segment);
2363 
2364 
2365 /* openvswitch calls this on rx path, so we need a different check.
2366  */
2367 static inline bool skb_needs_check(struct sk_buff *skb, bool tx_path)
2368 {
2369         if (tx_path)
2370                 return skb->ip_summed != CHECKSUM_PARTIAL;
2371         else
2372                 return skb->ip_summed == CHECKSUM_NONE;
2373 }
2374 
2375 /**
2376  *      __skb_gso_segment - Perform segmentation on skb.
2377  *      @skb: buffer to segment
2378  *      @features: features for the output path (see dev->features)
2379  *      @tx_path: whether it is called in TX path
2380  *
2381  *      This function segments the given skb and returns a list of segments.
2382  *
2383  *      It may return NULL if the skb requires no segmentation.  This is
2384  *      only possible when GSO is used for verifying header integrity.
2385  */
2386 struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
2387                                   netdev_features_t features, bool tx_path)
2388 {
2389         if (unlikely(skb_needs_check(skb, tx_path))) {
2390                 int err;
2391 
2392                 skb_warn_bad_offload(skb);
2393 
2394                 if (skb_header_cloned(skb) &&
2395                     (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
2396                         return ERR_PTR(err);
2397         }
2398 
2399         SKB_GSO_CB(skb)->mac_offset = skb_headroom(skb);
2400         SKB_GSO_CB(skb)->encap_level = 0;
2401 
2402         skb_reset_mac_header(skb);
2403         skb_reset_mac_len(skb);
2404 
2405         return skb_mac_gso_segment(skb, features);
2406 }
2407 EXPORT_SYMBOL(__skb_gso_segment);
2408 
2409 /* Take action when hardware reception checksum errors are detected. */
2410 #ifdef CONFIG_BUG
2411 void netdev_rx_csum_fault(struct net_device *dev)
2412 {
2413         if (net_ratelimit()) {
2414                 pr_err("%s: hw csum failure\n", dev ? dev->name : "<unknown>");
2415                 dump_stack();
2416         }
2417 }
2418 EXPORT_SYMBOL(netdev_rx_csum_fault);
2419 #endif
2420 
2421 /* Actually, we should eliminate this check as soon as we know, that:
2422  * 1. IOMMU is present and allows to map all the memory.
2423  * 2. No high memory really exists on this machine.
2424  */
2425 
2426 static int illegal_highdma(const struct net_device *dev, struct sk_buff *skb)
2427 {
2428 #ifdef CONFIG_HIGHMEM
2429         int i;
2430         if (!(dev->features & NETIF_F_HIGHDMA)) {
2431                 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2432                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2433                         if (PageHighMem(skb_frag_page(frag)))
2434                                 return 1;
2435                 }
2436         }
2437 
2438         if (PCI_DMA_BUS_IS_PHYS) {
2439                 struct device *pdev = dev->dev.parent;
2440 
2441                 if (!pdev)
2442                         return 0;
2443                 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2444                         skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2445                         dma_addr_t addr = page_to_phys(skb_frag_page(frag));
2446                         if (!pdev->dma_mask || addr + PAGE_SIZE - 1 > *pdev->dma_mask)
2447                                 return 1;
2448                 }
2449         }
2450 #endif
2451         return 0;
2452 }
2453 
2454 struct dev_gso_cb {
2455         void (*destructor)(struct sk_buff *skb);
2456 };
2457 
2458 #define DEV_GSO_CB(skb) ((struct dev_gso_cb *)(skb)->cb)
2459 
2460 static void dev_gso_skb_destructor(struct sk_buff *skb)
2461 {
2462         struct dev_gso_cb *cb;
2463 
2464         kfree_skb_list(skb->next);
2465         skb->next = NULL;
2466 
2467         cb = DEV_GSO_CB(skb);
2468         if (cb->destructor)
2469                 cb->destructor(skb);
2470 }
2471 
2472 /**
2473  *      dev_gso_segment - Perform emulated hardware segmentation on skb.
2474  *      @skb: buffer to segment
2475  *      @features: device features as applicable to this skb
2476  *
2477  *      This function segments the given skb and stores the list of segments
2478  *      in skb->next.
2479  */
2480 static int dev_gso_segment(struct sk_buff *skb, netdev_features_t features)
2481 {
2482         struct sk_buff *segs;
2483 
2484         segs = skb_gso_segment(skb, features);
2485 
2486         /* Verifying header integrity only. */
2487         if (!segs)
2488                 return 0;
2489 
2490         if (IS_ERR(segs))
2491                 return PTR_ERR(segs);
2492 
2493         skb->next = segs;
2494         DEV_GSO_CB(skb)->destructor = skb->destructor;
2495         skb->destructor = dev_gso_skb_destructor;
2496 
2497         return 0;
2498 }
2499 
2500 static netdev_features_t harmonize_features(struct sk_buff *skb,
2501                                             const struct net_device *dev,
2502                                             netdev_features_t features)
2503 {
2504         int tmp;
2505 
2506         if (skb->ip_summed != CHECKSUM_NONE &&
2507             !can_checksum_protocol(features, skb_network_protocol(skb, &tmp))) {
2508                 features &= ~NETIF_F_ALL_CSUM;
2509         } else if (illegal_highdma(dev, skb)) {
2510                 features &= ~NETIF_F_SG;
2511         }
2512 
2513         return features;
2514 }
2515 
2516 netdev_features_t netif_skb_dev_features(struct sk_buff *skb,
2517                                          const struct net_device *dev)
2518 {
2519         __be16 protocol = skb->protocol;
2520         netdev_features_t features = dev->features;
2521 
2522         if (skb_shinfo(skb)->gso_segs > dev->gso_max_segs)
2523                 features &= ~NETIF_F_GSO_MASK;
2524 
2525         if (protocol == htons(ETH_P_8021Q) || protocol == htons(ETH_P_8021AD)) {
2526                 struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
2527                 protocol = veh->h_vlan_encapsulated_proto;
2528         } else if (!vlan_tx_tag_present(skb)) {
2529                 return harmonize_features(skb, dev, features);
2530         }
2531 
2532         features &= (dev->vlan_features | NETIF_F_HW_VLAN_CTAG_TX |
2533                                                NETIF_F_HW_VLAN_STAG_TX);
2534 
2535         if (protocol == htons(ETH_P_8021Q) || protocol == htons(ETH_P_8021AD))
2536                 features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST |
2537                                 NETIF_F_GEN_CSUM | NETIF_F_HW_VLAN_CTAG_TX |
2538                                 NETIF_F_HW_VLAN_STAG_TX;
2539 
2540         return harmonize_features(skb, dev, features);
2541 }
2542 EXPORT_SYMBOL(netif_skb_dev_features);
2543 
2544 int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
2545                         struct netdev_queue *txq)
2546 {
2547         const struct net_device_ops *ops = dev->netdev_ops;
2548         int rc = NETDEV_TX_OK;
2549         unsigned int skb_len;
2550 
2551         if (likely(!skb->next)) {
2552                 netdev_features_t features;
2553 
2554                 /*
2555                  * If device doesn't need skb->dst, release it right now while
2556                  * its hot in this cpu cache
2557                  */
2558                 if (dev->priv_flags & IFF_XMIT_DST_RELEASE)
2559                         skb_dst_drop(skb);
2560 
2561                 features = netif_skb_features(skb);
2562 
2563                 if (vlan_tx_tag_present(skb) &&
2564                     !vlan_hw_offload_capable(features, skb->vlan_proto)) {
2565                         skb = __vlan_put_tag(skb, skb->vlan_proto,
2566                                              vlan_tx_tag_get(skb));
2567                         if (unlikely(!skb))
2568                                 goto out;
2569 
2570                         skb->vlan_tci = 0;
2571                 }
2572 
2573                 /* If encapsulation offload request, verify we are testing
2574                  * hardware encapsulation features instead of standard
2575                  * features for the netdev
2576                  */
2577                 if (skb->encapsulation)
2578                         features &= dev->hw_enc_features;
2579 
2580                 if (netif_needs_gso(skb, features)) {
2581                         if (unlikely(dev_gso_segment(skb, features)))
2582                                 goto out_kfree_skb;
2583                         if (skb->next)
2584                                 goto gso;
2585                 } else {
2586                         if (skb_needs_linearize(skb, features) &&
2587                             __skb_linearize(skb))
2588                                 goto out_kfree_skb;
2589 
2590                         /* If packet is not checksummed and device does not
2591                          * support checksumming for this protocol, complete
2592                          * checksumming here.
2593                          */
2594                         if (skb->ip_summed == CHECKSUM_PARTIAL) {
2595                                 if (skb->encapsulation)
2596                                         skb_set_inner_transport_header(skb,
2597                                                 skb_checksum_start_offset(skb));
2598                                 else
2599                                         skb_set_transport_header(skb,
2600                                                 skb_checksum_start_offset(skb));
2601                                 if (!(features & NETIF_F_ALL_CSUM) &&
2602                                      skb_checksum_help(skb))
2603                                         goto out_kfree_skb;
2604                         }
2605                 }
2606 
2607                 if (!list_empty(&ptype_all))
2608                         dev_queue_xmit_nit(skb, dev);
2609 
2610                 skb_len = skb->len;
2611                 trace_net_dev_start_xmit(skb, dev);
2612                 rc = ops->ndo_start_xmit(skb, dev);
2613                 trace_net_dev_xmit(skb, rc, dev, skb_len);
2614                 if (rc == NETDEV_TX_OK)
2615                         txq_trans_update(txq);
2616                 return rc;
2617         }
2618 
2619 gso:
2620         do {
2621                 struct sk_buff *nskb = skb->next;
2622 
2623                 skb->next = nskb->next;
2624                 nskb->next = NULL;
2625 
2626                 if (!list_empty(&ptype_all))
2627                         dev_queue_xmit_nit(nskb, dev);
2628 
2629                 skb_len = nskb->len;
2630                 trace_net_dev_start_xmit(nskb, dev);
2631                 rc = ops->ndo_start_xmit(nskb, dev);
2632                 trace_net_dev_xmit(nskb, rc, dev, skb_len);
2633                 if (unlikely(rc != NETDEV_TX_OK)) {
2634                         if (rc & ~NETDEV_TX_MASK)
2635                                 goto out_kfree_gso_skb;
2636                         nskb->next = skb->next;
2637                         skb->next = nskb;
2638                         return rc;
2639                 }
2640                 txq_trans_update(txq);
2641                 if (unlikely(netif_xmit_stopped(txq) && skb->next))
2642                         return NETDEV_TX_BUSY;
2643         } while (skb->next);
2644 
2645 out_kfree_gso_skb:
2646         if (likely(skb->next == NULL)) {
2647                 skb->destructor = DEV_GSO_CB(skb)->destructor;
2648                 consume_skb(skb);
2649                 return rc;
2650         }
2651 out_kfree_skb:
2652         kfree_skb(skb);
2653 out:
2654         return rc;
2655 }
2656 EXPORT_SYMBOL_GPL(dev_hard_start_xmit);
2657 
2658 static void qdisc_pkt_len_init(struct sk_buff *skb)
2659 {
2660         const struct skb_shared_info *shinfo = skb_shinfo(skb);
2661 
2662         qdisc_skb_cb(skb)->pkt_len = skb->len;
2663 
2664         /* To get more precise estimation of bytes sent on wire,
2665          * we add to pkt_len the headers size of all segments
2666          */
2667         if (shinfo->gso_size)  {
2668                 unsigned int hdr_len;
2669                 u16 gso_segs = shinfo->gso_segs;
2670 
2671                 /* mac layer + network layer */
2672                 hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
2673 
2674                 /* + transport layer */
2675                 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
2676                         hdr_len += tcp_hdrlen(skb);
2677                 else
2678                         hdr_len += sizeof(struct udphdr);
2679 
2680                 if (shinfo->gso_type & SKB_GSO_DODGY)
2681                         gso_segs = DIV_ROUND_UP(skb->len - hdr_len,
2682                                                 shinfo->gso_size);
2683 
2684                 qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;
2685         }
2686 }
2687 
2688 static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
2689                                  struct net_device *dev,
2690                                  struct netdev_queue *txq)
2691 {
2692         spinlock_t *root_lock = qdisc_lock(q);
2693         bool contended;
2694         int rc;
2695 
2696         qdisc_pkt_len_init(skb);
2697         qdisc_calculate_pkt_len(skb, q);
2698         /*
2699          * Heuristic to force contended enqueues to serialize on a
2700          * separate lock before trying to get qdisc main lock.
2701          * This permits __QDISC_STATE_RUNNING owner to get the lock more often
2702          * and dequeue packets faster.
2703          */
2704         contended = qdisc_is_running(q);
2705         if (unlikely(contended))
2706                 spin_lock(&q->busylock);
2707 
2708         spin_lock(root_lock);
2709         if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
2710                 kfree_skb(skb);
2711                 rc = NET_XMIT_DROP;
2712         } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q) &&
2713                    qdisc_run_begin(q)) {
2714                 /*
2715                  * This is a work-conserving queue; there are no old skbs
2716                  * waiting to be sent out; and the qdisc is not running -
2717                  * xmit the skb directly.
2718                  */
2719                 if (!(dev->priv_flags & IFF_XMIT_DST_RELEASE))
2720                         skb_dst_force(skb);
2721 
2722                 qdisc_bstats_update(q, skb);
2723 
2724                 if (sch_direct_xmit(skb, q, dev, txq, root_lock)) {
2725                         if (unlikely(contended)) {
2726                                 spin_unlock(&q->busylock);
2727                                 contended = false;
2728                         }
2729                         __qdisc_run(q);
2730                 } else
2731                         qdisc_run_end(q);
2732 
2733                 rc = NET_XMIT_SUCCESS;
2734         } else {
2735                 skb_dst_force(skb);
2736                 rc = q->enqueue(skb, q) & NET_XMIT_MASK;
2737                 if (qdisc_run_begin(q)) {
2738                         if (unlikely(contended)) {
2739                                 spin_unlock(&q->busylock);
2740                                 contended = false;
2741                         }
2742                         __qdisc_run(q);
2743                 }
2744         }
2745         spin_unlock(root_lock);
2746         if (unlikely(contended))
2747                 spin_unlock(&q->busylock);
2748         return rc;
2749 }
2750 
2751 #if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
2752 static void skb_update_prio(struct sk_buff *skb)
2753 {
2754         struct netprio_map *map = rcu_dereference_bh(skb->dev->priomap);
2755 
2756         if (!skb->priority && skb->sk && map) {
2757                 unsigned int prioidx = skb->sk->sk_cgrp_prioidx;
2758 
2759                 if (prioidx < map->priomap_len)
2760                         skb->priority = map->priomap[prioidx];
2761         }
2762 }
2763 #else
2764 #define skb_update_prio(skb)
2765 #endif
2766 
2767 static DEFINE_PER_CPU(int, xmit_recursion);
2768 #define RECURSION_LIMIT 10
2769 
2770 /**
2771  *      dev_loopback_xmit - loop back @skb
2772  *      @skb: buffer to transmit
2773  */
2774 int dev_loopback_xmit(struct sk_buff *skb)
2775 {
2776         skb_reset_mac_header(skb);
2777         __skb_pull(skb, skb_network_offset(skb));
2778         skb->pkt_type = PACKET_LOOPBACK;
2779         skb->ip_summed = CHECKSUM_UNNECESSARY;
2780         WARN_ON(!skb_dst(skb));
2781         skb_dst_force(skb);
2782         netif_rx_ni(skb);
2783         return 0;
2784 }
2785 EXPORT_SYMBOL(dev_loopback_xmit);
2786 
2787 /**
2788  *      __dev_queue_xmit - transmit a buffer
2789  *      @skb: buffer to transmit
2790  *      @accel_priv: private data used for L2 forwarding offload
2791  *
2792  *      Queue a buffer for transmission to a network device. The caller must
2793  *      have set the device and priority and built the buffer before calling
2794  *      this function. The function can be called from an interrupt.
2795  *
2796  *      A negative errno code is returned on a failure. A success does not
2797  *      guarantee the frame will be transmitted as it may be dropped due
2798  *      to congestion or traffic shaping.
2799  *
2800  * -----------------------------------------------------------------------------------
2801  *      I notice this method can also return errors from the queue disciplines,
2802  *      including NET_XMIT_DROP, which is a positive value.  So, errors can also
2803  *      be positive.
2804  *
2805  *      Regardless of the return value, the skb is consumed, so it is currently
2806  *      difficult to retry a send to this method.  (You can bump the ref count
2807  *      before sending to hold a reference for retry if you are careful.)
2808  *
2809  *      When calling this method, interrupts MUST be enabled.  This is because
2810  *      the BH enable code must have IRQs enabled so that it will not deadlock.
2811  *          --BLG
2812  */
2813 static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
2814 {
2815         struct net_device *dev = skb->dev;
2816         struct netdev_queue *txq;
2817         struct Qdisc *q;
2818         int rc = -ENOMEM;
2819 
2820         skb_reset_mac_header(skb);
2821 
2822         /* Disable soft irqs for various locks below. Also
2823          * stops preemption for RCU.
2824          */
2825         rcu_read_lock_bh();
2826 
2827         skb_update_prio(skb);
2828 
2829         txq = netdev_pick_tx(dev, skb, accel_priv);
2830         q = rcu_dereference_bh(txq->qdisc);
2831 
2832 #ifdef CONFIG_NET_CLS_ACT
2833         skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_EGRESS);
2834 #endif
2835         trace_net_dev_queue(skb);
2836         if (q->enqueue) {
2837                 rc = __dev_xmit_skb(skb, q, dev, txq);
2838                 goto out;
2839         }
2840 
2841         /* The device has no queue. Common case for software devices:
2842            loopback, all the sorts of tunnels...
2843 
2844            Really, it is unlikely that netif_tx_lock protection is necessary
2845            here.  (f.e. loopback and IP tunnels are clean ignoring statistics
2846            counters.)
2847            However, it is possible, that they rely on protection
2848            made by us here.
2849 
2850            Check this and shot the lock. It is not prone from deadlocks.
2851            Either shot noqueue qdisc, it is even simpler 8)
2852          */
2853         if (dev->flags & IFF_UP) {
2854                 int cpu = smp_processor_id(); /* ok because BHs are off */
2855 
2856                 if (txq->xmit_lock_owner != cpu) {
2857 
2858                         if (__this_cpu_read(xmit_recursion) > RECURSION_LIMIT)
2859                                 goto recursion_alert;
2860 
2861                         HARD_TX_LOCK(dev, txq, cpu);
2862 
2863                         if (!netif_xmit_stopped(txq)) {
2864                                 __this_cpu_inc(xmit_recursion);
2865                                 rc = dev_hard_start_xmit(skb, dev, txq);
2866                                 __this_cpu_dec(xmit_recursion);
2867                                 if (dev_xmit_complete(rc)) {
2868                                         HARD_TX_UNLOCK(dev, txq);
2869                                         goto out;
2870                                 }
2871                         }
2872                         HARD_TX_UNLOCK(dev, txq);
2873                         net_crit_ratelimited("Virtual device %s asks to queue packet!\n",
2874                                              dev->name);
2875                 } else {
2876                         /* Recursion is detected! It is possible,
2877                          * unfortunately
2878                          */
2879 recursion_alert:
2880                         net_crit_ratelimited("Dead loop on virtual device %s, fix it urgently!\n",
2881                                              dev->name);
2882                 }
2883         }
2884 
2885         rc = -ENETDOWN;
2886         rcu_read_unlock_bh();
2887 
2888         kfree_skb(skb);
2889         return rc;
2890 out:
2891         rcu_read_unlock_bh();
2892         return rc;
2893 }
2894 
2895 int dev_queue_xmit(struct sk_buff *skb)
2896 {
2897         return __dev_queue_xmit(skb, NULL);
2898 }
2899 EXPORT_SYMBOL(dev_queue_xmit);
2900 
2901 int dev_queue_xmit_accel(struct sk_buff *skb, void *accel_priv)
2902 {
2903         return __dev_queue_xmit(skb, accel_priv);
2904 }
2905 EXPORT_SYMBOL(dev_queue_xmit_accel);
2906 
2907 
2908 /*=======================================================================
2909                         Receiver routines
2910   =======================================================================*/
2911 
2912 int netdev_max_backlog __read_mostly = 1000;
2913 EXPORT_SYMBOL(netdev_max_backlog);
2914 
2915 int netdev_tstamp_prequeue __read_mostly = 1;
2916 int netdev_budget __read_mostly = 300;
2917 int weight_p __read_mostly = 64;            /* old backlog weight */
2918 
2919 /* Called with irq disabled */
2920 static inline void ____napi_schedule(struct softnet_data *sd,
2921                                      struct napi_struct *napi)
2922 {
2923         list_add_tail(&napi->poll_list, &sd->poll_list);
2924         __raise_softirq_irqoff(NET_RX_SOFTIRQ);
2925 }
2926 
2927 #ifdef CONFIG_RPS
2928 
2929 /* One global table that all flow-based protocols share. */
2930 struct rps_sock_flow_table __rcu *rps_sock_flow_table __read_mostly;
2931 EXPORT_SYMBOL(rps_sock_flow_table);
2932 
2933 struct static_key rps_needed __read_mostly;
2934 
2935 static struct rps_dev_flow *
2936 set_rps_cpu(struct net_device *dev, struct sk_buff *skb,
2937             struct rps_dev_flow *rflow, u16 next_cpu)
2938 {
2939         if (next_cpu != RPS_NO_CPU) {
2940 #ifdef CONFIG_RFS_ACCEL
2941                 struct netdev_rx_queue *rxqueue;
2942                 struct rps_dev_flow_table *flow_table;
2943                 struct rps_dev_flow *old_rflow;
2944                 u32 flow_id;
2945                 u16 rxq_index;
2946                 int rc;
2947 
2948                 /* Should we steer this flow to a different hardware queue? */
2949                 if (!skb_rx_queue_recorded(skb) || !dev->rx_cpu_rmap ||
2950                     !(dev->features & NETIF_F_NTUPLE))
2951                         goto out;
2952                 rxq_index = cpu_rmap_lookup_index(dev->rx_cpu_rmap, next_cpu);
2953                 if (rxq_index == skb_get_rx_queue(skb))
2954                         goto out;
2955 
2956                 rxqueue = dev->_rx + rxq_index;
2957                 flow_table = rcu_dereference(rxqueue->rps_flow_table);
2958                 if (!flow_table)
2959                         goto out;
2960                 flow_id = skb->rxhash & flow_table->mask;
2961                 rc = dev->netdev_ops->ndo_rx_flow_steer(dev, skb,
2962                                                         rxq_index, flow_id);
2963                 if (rc < 0)
2964                         goto out;
2965                 old_rflow = rflow;
2966                 rflow = &flow_table->flows[flow_id];
2967                 rflow->filter = rc;
2968                 if (old_rflow->filter == rflow->filter)
2969                         old_rflow->filter = RPS_NO_FILTER;
2970         out:
2971 #endif
2972                 rflow->last_qtail =
2973                         per_cpu(softnet_data, next_cpu).input_queue_head;
2974         }
2975 
2976         rflow->cpu = next_cpu;
2977         return rflow;
2978 }
2979 
2980 /*
2981  * get_rps_cpu is called from netif_receive_skb and returns the target
2982  * CPU from the RPS map of the receiving queue for a given skb.
2983  * rcu_read_lock must be held on entry.
2984  */
2985 static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
2986                        struct rps_dev_flow **rflowp)
2987 {
2988         struct netdev_rx_queue *rxqueue;
2989         struct rps_map *map;
2990         struct rps_dev_flow_table *flow_table;
2991         struct rps_sock_flow_table *sock_flow_table;
2992         int cpu = -1;
2993         u16 tcpu;
2994 
2995         if (skb_rx_queue_recorded(skb)) {
2996                 u16 index = skb_get_rx_queue(skb);
2997                 if (unlikely(index >= dev->real_num_rx_queues)) {
2998                         WARN_ONCE(dev->real_num_rx_queues > 1,
2999                                   "%s received packet on queue %u, but number "
3000                                   "of RX queues is %u\n",
3001                                   dev->name, index, dev->real_num_rx_queues);
3002                         goto done;
3003                 }
3004                 rxqueue = dev->_rx + index;
3005         } else
3006                 rxqueue = dev->_rx;
3007 
3008         map = rcu_dereference(rxqueue->rps_map);
3009         if (map) {
3010                 if (map->len == 1 &&
3011                     !rcu_access_pointer(rxqueue->rps_flow_table)) {
3012                         tcpu = map->cpus[0];
3013                         if (cpu_online(tcpu))
3014                                 cpu = tcpu;
3015                         goto done;
3016                 }
3017         } else if (!rcu_access_pointer(rxqueue->rps_flow_table)) {
3018                 goto done;
3019         }
3020 
3021         skb_reset_network_header(skb);
3022         if (!skb_get_hash(skb))
3023                 goto done;
3024 
3025         flow_table = rcu_dereference(rxqueue->rps_flow_table);
3026         sock_flow_table = rcu_dereference(rps_sock_flow_table);
3027         if (flow_table && sock_flow_table) {
3028                 u16 next_cpu;
3029                 struct rps_dev_flow *rflow;
3030 
3031                 rflow = &flow_table->flows[skb->rxhash & flow_table->mask];
3032                 tcpu = rflow->cpu;
3033 
3034                 next_cpu = sock_flow_table->ents[skb->rxhash &
3035                     sock_flow_table->mask];
3036 
3037                 /*
3038                  * If the desired CPU (where last recvmsg was done) is
3039                  * different from current CPU (one in the rx-queue flow
3040                  * table entry), switch if one of the following holds:
3041                  *   - Current CPU is unset (equal to RPS_NO_CPU).
3042                  *   - Current CPU is offline.
3043                  *   - The current CPU's queue tail has advanced beyond the
3044                  *     last packet that was enqueued using this table entry.
3045                  *     This guarantees that all previous packets for the flow
3046                  *     have been dequeued, thus preserving in order delivery.
3047                  */
3048                 if (unlikely(tcpu != next_cpu) &&
3049                     (tcpu == RPS_NO_CPU || !cpu_online(tcpu) ||
3050                      ((int)(per_cpu(softnet_data, tcpu).input_queue_head -
3051                       rflow->last_qtail)) >= 0)) {
3052                         tcpu = next_cpu;
3053                         rflow = set_rps_cpu(dev, skb, rflow, next_cpu);
3054                 }
3055 
3056                 if (tcpu != RPS_NO_CPU && cpu_online(tcpu)) {
3057                         *rflowp = rflow;
3058                         cpu = tcpu;
3059                         goto done;
3060                 }
3061         }
3062 
3063         if (map) {
3064                 tcpu = map->cpus[((u64) skb->rxhash * map->len) >> 32];
3065 
3066                 if (cpu_online(tcpu)) {
3067                         cpu = tcpu;
3068                         goto done;
3069                 }
3070         }
3071 
3072 done:
3073         return cpu;
3074 }
3075 
3076 #ifdef CONFIG_RFS_ACCEL
3077 
3078 /**
3079  * rps_may_expire_flow - check whether an RFS hardware filter may be removed
3080  * @dev: Device on which the filter was set
3081  * @rxq_index: RX queue index
3082  * @flow_id: Flow ID passed to ndo_rx_flow_steer()
3083  * @filter_id: Filter ID returned by ndo_rx_flow_steer()
3084  *
3085  * Drivers that implement ndo_rx_flow_steer() should periodically call
3086  * this function for each installed filter and remove the filters for
3087  * which it returns %true.
3088  */
3089 bool rps_may_expire_flow(struct net_device *dev, u16 rxq_index,
3090                          u32 flow_id, u16 filter_id)
3091 {
3092         struct netdev_rx_queue *rxqueue = dev->_rx + rxq_index;
3093         struct rps_dev_flow_table *flow_table;
3094         struct rps_dev_flow *rflow;
3095         bool expire = true;
3096         int cpu;
3097 
3098         rcu_read_lock();
3099         flow_table = rcu_dereference(rxqueue->rps_flow_table);
3100         if (flow_table && flow_id <= flow_table->mask) {
3101                 rflow = &flow_table->flows[flow_id];
3102                 cpu = ACCESS_ONCE(rflow->cpu);
3103                 if (rflow->filter == filter_id && cpu != RPS_NO_CPU &&
3104                     ((int)(per_cpu(softnet_data, cpu).input_queue_head -
3105                            rflow->last_qtail) <
3106                      (int)(10 * flow_table->mask)))
3107                         expire = false;
3108         }
3109         rcu_read_unlock();
3110         return expire;
3111 }
3112 EXPORT_SYMBOL(rps_may_expire_flow);
3113 
3114 #endif /* CONFIG_RFS_ACCEL */
3115 
3116 /* Called from hardirq (IPI) context */
3117 static void rps_trigger_softirq(void *data)
3118 {
3119         struct softnet_data *sd = data;
3120 
3121         ____napi_schedule(sd, &sd->backlog);
3122         sd->received_rps++;
3123 }
3124 
3125 #endif /* CONFIG_RPS */
3126 
3127 /*
3128  * Check if this softnet_data structure is another cpu one
3129  * If yes, queue it to our IPI list and return 1
3130  * If no, return 0
3131  */
3132 static int rps_ipi_queued(struct softnet_data *sd)
3133 {
3134 #ifdef CONFIG_RPS
3135         struct softnet_data *mysd = &__get_cpu_var(softnet_data);
3136 
3137         if (sd != mysd) {
3138                 sd->rps_ipi_next = mysd->rps_ipi_list;
3139                 mysd->rps_ipi_list = sd;
3140 
3141                 __raise_softirq_irqoff(NET_RX_SOFTIRQ);
3142                 return 1;
3143         }
3144 #endif /* CONFIG_RPS */
3145         return 0;
3146 }
3147 
3148 #ifdef CONFIG_NET_FLOW_LIMIT
3149 int netdev_flow_limit_table_len __read_mostly = (1 << 12);
3150 #endif
3151 
3152 static bool skb_flow_limit(struct sk_buff *skb, unsigned int qlen)
3153 {
3154 #ifdef CONFIG_NET_FLOW_LIMIT
3155         struct sd_flow_limit *fl;
3156         struct softnet_data *sd;
3157         unsigned int old_flow, new_flow;
3158 
3159         if (qlen < (netdev_max_backlog >> 1))
3160                 return false;
3161 
3162         sd = &__get_cpu_var(softnet_data);
3163 
3164         rcu_read_lock();
3165         fl = rcu_dereference(sd->flow_limit);
3166         if (fl) {
3167                 new_flow = skb_get_hash(skb) & (fl->num_buckets - 1);
3168                 old_flow = fl->history[fl->history_head];
3169                 fl->history[fl->history_head] = new_flow;
3170 
3171                 fl->history_head++;
3172                 fl->history_head &= FLOW_LIMIT_HISTORY - 1;
3173 
3174                 if (likely(fl->buckets[old_flow]))
3175                         fl->buckets[old_flow]--;
3176 
3177                 if (++fl->buckets[new_flow] > (FLOW_LIMIT_HISTORY >> 1)) {
3178                         fl->count++;
3179                         rcu_read_unlock();
3180                         return true;
3181                 }
3182         }
3183         rcu_read_unlock();
3184 #endif
3185         return false;
3186 }
3187 
3188 /*
3189  * enqueue_to_backlog is called to queue an skb to a per CPU backlog
3190  * queue (may be a remote CPU queue).
3191  */
3192 static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
3193                               unsigned int *qtail)
3194 {
3195         struct softnet_data *sd;
3196         unsigned long flags;
3197         unsigned int qlen;
3198 
3199         sd = &per_cpu(softnet_data, cpu);
3200 
3201         local_irq_save(flags);
3202 
3203         rps_lock(sd);
3204         qlen = skb_queue_len(&sd->input_pkt_queue);
3205         if (qlen <= netdev_max_backlog && !skb_flow_limit(skb, qlen)) {
3206                 if (skb_queue_len(&sd->input_pkt_queue)) {
3207 enqueue:
3208                         __skb_queue_tail(&sd->input_pkt_queue, skb);
3209                         input_queue_tail_incr_save(sd, qtail);
3210                         rps_unlock(sd);
3211                         local_irq_restore(flags);
3212                         return NET_RX_SUCCESS;
3213                 }
3214 
3215                 /* Schedule NAPI for backlog device
3216                  * We can use non atomic operation since we own the queue lock
3217                  */
3218                 if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) {
3219                         if (!rps_ipi_queued(sd))
3220                                 ____napi_schedule(sd, &sd->backlog);
3221                 }
3222                 goto enqueue;
3223         }
3224 
3225         sd->dropped++;
3226         rps_unlock(sd);
3227 
3228         local_irq_restore(flags);
3229 
3230         atomic_long_inc(&skb->dev->rx_dropped);
3231         kfree_skb(skb);
3232         return NET_RX_DROP;
3233 }
3234 
3235 static int netif_rx_internal(struct sk_buff *skb)
3236 {
3237         int ret;
3238 
3239         /* if netpoll wants it, pretend we never saw it */
3240         if (netpoll_rx(skb))
3241                 return NET_RX_DROP;
3242 
3243         net_timestamp_check(netdev_tstamp_prequeue, skb);
3244 
3245         trace_netif_rx(skb);
3246 #ifdef CONFIG_RPS
3247         if (static_key_false(&rps_needed)) {
3248                 struct rps_dev_flow voidflow, *rflow = &voidflow;
3249                 int cpu;
3250 
3251                 preempt_disable();
3252                 rcu_read_lock();
3253 
3254                 cpu = get_rps_cpu(skb->dev, skb, &rflow);
3255                 if (cpu < 0)
3256                         cpu = smp_processor_id();
3257 
3258                 ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
3259 
3260                 rcu_read_unlock();
3261                 preempt_enable();
3262         } else
3263 #endif
3264         {
3265                 unsigned int qtail;
3266                 ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
3267                 put_cpu();
3268         }
3269         return ret;
3270 }
3271 
3272 /**
3273  *      netif_rx        -       post buffer to the network code
3274  *      @skb: buffer to post
3275  *
3276  *      This function receives a packet from a device driver and queues it for
3277  *      the upper (protocol) levels to process.  It always succeeds. The buffer
3278  *      may be dropped during processing for congestion control or by the
3279  *      protocol layers.
3280  *
3281  *      return values:
3282  *      NET_RX_SUCCESS  (no congestion)
3283  *      NET_RX_DROP     (packet was dropped)
3284  *
3285  */
3286 
3287 int netif_rx(struct sk_buff *skb)
3288 {
3289         trace_netif_rx_entry(skb);
3290 
3291         return netif_rx_internal(skb);
3292 }
3293 EXPORT_SYMBOL(netif_rx);
3294 
3295 int netif_rx_ni(struct sk_buff *skb)
3296 {
3297         int err;
3298 
3299         trace_netif_rx_ni_entry(skb);
3300 
3301         preempt_disable();
3302         err = netif_rx_internal(skb);
3303         if (local_softirq_pending())
3304                 do_softirq();
3305         preempt_enable();
3306 
3307         return err;
3308 }
3309 EXPORT_SYMBOL(netif_rx_ni);
3310 
3311 static void net_tx_action(struct softirq_action *h)
3312 {
3313         struct softnet_data *sd = &__get_cpu_var(softnet_data);
3314 
3315         if (sd->completion_queue) {
3316                 struct sk_buff *clist;
3317 
3318                 local_irq_disable();
3319                 clist = sd->completion_queue;
3320                 sd->completion_queue = NULL;
3321                 local_irq_enable();
3322 
3323                 while (clist) {
3324                         struct sk_buff *skb = clist;
3325                         clist = clist->next;
3326 
3327                         WARN_ON(atomic_read(&skb->users));
3328                         if (likely(get_kfree_skb_cb(skb)->reason == SKB_REASON_CONSUMED))
3329                                 trace_consume_skb(skb);
3330                         else
3331                                 trace_kfree_skb(skb, net_tx_action);
3332                         __kfree_skb(skb);
3333                 }
3334         }
3335 
3336         if (sd->output_queue) {
3337                 struct Qdisc *head;
3338 
3339                 local_irq_disable();
3340                 head = sd->output_queue;
3341                 sd->output_queue = NULL;
3342                 sd->output_queue_tailp = &sd->output_queue;
3343                 local_irq_enable();
3344 
3345                 while (head) {
3346                         struct Qdisc *q = head;
3347                         spinlock_t *root_lock;
3348 
3349                         head = head->next_sched;
3350 
3351                         root_lock = qdisc_lock(q);
3352                         if (spin_trylock(root_lock)) {
3353                                 smp_mb__before_clear_bit();
3354                                 clear_bit(__QDISC_STATE_SCHED,
3355                                           &q->state);
3356                                 qdisc_run(q);
3357                                 spin_unlock(root_lock);
3358                         } else {
3359                                 if (!test_bit(__QDISC_STATE_DEACTIVATED,
3360                                               &q->state)) {
3361                                         __netif_reschedule(q);
3362                                 } else {
3363                                         smp_mb__before_clear_bit();
3364                                         clear_bit(__QDISC_STATE_SCHED,
3365                                                   &q->state);
3366                                 }
3367                         }
3368                 }
3369         }
3370 }
3371 
3372 #if (defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)) && \
3373     (defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE))
3374 /* This hook is defined here for ATM LANE */
3375 int (*br_fdb_test_addr_hook)(struct net_device *dev,
3376                              unsigned char *addr) __read_mostly;
3377 EXPORT_SYMBOL_GPL(br_fdb_test_addr_hook);
3378 #endif
3379 
3380 #ifdef CONFIG_NET_CLS_ACT
3381 /* TODO: Maybe we should just force sch_ingress to be compiled in
3382  * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
3383  * a compare and 2 stores extra right now if we dont have it on
3384  * but have CONFIG_NET_CLS_ACT
3385  * NOTE: This doesn't stop any functionality; if you dont have
3386  * the ingress scheduler, you just can't add policies on ingress.
3387  *
3388  */
3389 static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq)
3390 {
3391         struct net_device *dev = skb->dev;
3392         u32 ttl = G_TC_RTTL(skb->tc_verd);
3393         int result = TC_ACT_OK;
3394         struct Qdisc *q;
3395 
3396         if (unlikely(MAX_RED_LOOP < ttl++)) {
3397                 net_warn_ratelimited("Redir loop detected Dropping packet (%d->%d)\n",
3398                                      skb->skb_iif, dev->ifindex);
3399                 return TC_ACT_SHOT;
3400         }
3401 
3402         skb->tc_verd = SET_TC_RTTL(skb->tc_verd, ttl);
3403         skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);
3404 
3405         q = rxq->qdisc;
3406         if (q != &noop_qdisc) {
3407                 spin_lock(qdisc_lock(q));
3408                 if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
3409                         result = qdisc_enqueue_root(skb, q);
3410                 spin_unlock(qdisc_lock(q));
3411         }
3412 
3413         return result;
3414 }
3415 
3416 static inline struct sk_buff *handle_ing(struct sk_buff *skb,
3417                                          struct packet_type **pt_prev,
3418                                          int *ret, struct net_device *orig_dev)
3419 {
3420         struct netdev_queue *rxq = rcu_dereference(skb->dev->ingress_queue);
3421 
3422         if (!rxq || rxq->qdisc == &noop_qdisc)
3423                 goto out;
3424 
3425         if (*pt_prev) {
3426                 *ret = deliver_skb(skb, *pt_prev, orig_dev);
3427                 *pt_prev = NULL;
3428         }
3429 
3430         switch (ing_filter(skb, rxq)) {
3431         case TC_ACT_SHOT:
3432         case TC_ACT_STOLEN:
3433                 kfree_skb(skb);
3434                 return NULL;
3435         }
3436 
3437 out:
3438         skb->tc_verd = 0;
3439         return skb;
3440 }
3441 #endif
3442 
3443 /**
3444  *      netdev_rx_handler_register - register receive handler
3445  *      @dev: device to register a handler for
3446  *      @rx_handler: receive handler to register
3447  *      @rx_handler_data: data pointer that is used by rx handler
3448  *
3449  *      Register a receive hander for a device. This handler will then be
3450  *      called from __netif_receive_skb. A negative errno code is returned
3451  *      on a failure.
3452  *
3453  *      The caller must hold the rtnl_mutex.
3454  *
3455  *      For a general description of rx_handler, see enum rx_handler_result.
3456  */
3457 int netdev_rx_handler_register(struct net_device *dev,
3458                                rx_handler_func_t *rx_handler,
3459                                void *rx_handler_data)
3460 {
3461         ASSERT_RTNL();
3462 
3463         if (dev->rx_handler)
3464                 return -EBUSY;
3465 
3466         /* Note: rx_handler_data must be set before rx_handler */
3467         rcu_assign_pointer(dev->rx_handler_data, rx_handler_data);
3468         rcu_assign_pointer(dev->rx_handler, rx_handler);
3469 
3470         return 0;
3471 }
3472 EXPORT_SYMBOL_GPL(netdev_rx_handler_register);
3473 
3474 /**
3475  *      netdev_rx_handler_unregister - unregister receive handler
3476  *      @dev: device to unregister a handler from
3477  *
3478  *      Unregister a receive handler from a device.
3479  *
3480  *      The caller must hold the rtnl_mutex.
3481  */
3482 void netdev_rx_handler_unregister(struct net_device *dev)
3483 {
3484 
3485         ASSERT_RTNL();
3486         RCU_INIT_POINTER(dev->rx_handler, NULL);
3487         /* a reader seeing a non NULL rx_handler in a rcu_read_lock()
3488          * section has a guarantee to see a non NULL rx_handler_data
3489          * as well.
3490          */
3491         synchronize_net();
3492         RCU_INIT_POINTER(dev->rx_handler_data, NULL);
3493 }
3494 EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister);
3495 
3496 /*
3497  * Limit the use of PFMEMALLOC reserves to those protocols that implement
3498  * the special handling of PFMEMALLOC skbs.
3499  */
3500 static bool skb_pfmemalloc_protocol(struct sk_buff *skb)
3501 {
3502         switch (skb->protocol) {
3503         case __constant_htons(ETH_P_ARP):
3504         case __constant_htons(ETH_P_IP):
3505         case __constant_htons(ETH_P_IPV6):
3506         case __constant_htons(ETH_P_8021Q):
3507         case __constant_htons(ETH_P_8021AD):
3508                 return true;
3509         default:
3510                 return false;
3511         }
3512 }
3513 
3514 static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
3515 {
3516         struct packet_type *ptype, *pt_prev;
3517         rx_handler_func_t *rx_handler;
3518         struct net_device *orig_dev;
3519         struct net_device *null_or_dev;
3520         bool deliver_exact = false;
3521         int ret = NET_RX_DROP;
3522         __be16 type;
3523 
3524         net_timestamp_check(!netdev_tstamp_prequeue, skb);
3525 
3526         trace_netif_receive_skb(skb);
3527 
3528         /* if we've gotten here through NAPI, check netpoll */
3529         if (netpoll_receive_skb(skb))
3530                 goto out;
3531 
3532         orig_dev = skb->dev;
3533 
3534         skb_reset_network_header(skb);
3535         if (!skb_transport_header_was_set(skb))
3536                 skb_reset_transport_header(skb);
3537         skb_reset_mac_len(skb);
3538 
3539         pt_prev = NULL;
3540 
3541         rcu_read_lock();
3542 
3543 another_round:
3544         skb->skb_iif = skb->dev->ifindex;
3545 
3546         __this_cpu_inc(softnet_data.processed);
3547 
3548         if (skb->protocol == cpu_to_be16(ETH_P_8021Q) ||
3549             skb->protocol == cpu_to_be16(ETH_P_8021AD)) {
3550                 skb = vlan_untag(skb);
3551                 if (unlikely(!skb))
3552                         goto unlock;
3553         }
3554 
3555 #ifdef CONFIG_NET_CLS_ACT
3556         if (skb->tc_verd & TC_NCLS) {
3557                 skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
3558                 goto ncls;
3559         }
3560 #endif
3561 
3562         if (pfmemalloc)
3563                 goto skip_taps;
3564 
3565         list_for_each_entry_rcu(ptype, &ptype_all, list) {
3566                 if (!ptype->dev || ptype->dev == skb->dev) {
3567                         if (pt_prev)
3568                                 ret = deliver_skb(skb, pt_prev, orig_dev);
3569                         pt_prev = ptype;
3570                 }
3571         }
3572 
3573 skip_taps:
3574 #ifdef CONFIG_NET_CLS_ACT
3575         skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
3576         if (!skb)
3577                 goto unlock;
3578 ncls:
3579 #endif
3580 
3581         if (pfmemalloc && !skb_pfmemalloc_protocol(skb))
3582                 goto drop;
3583 
3584         if (vlan_tx_tag_present(skb)) {
3585                 if (pt_prev) {
3586                         ret = deliver_skb(skb, pt_prev, orig_dev);
3587                         pt_prev = NULL;
3588                 }
3589                 if (vlan_do_receive(&skb))
3590                         goto another_round;
3591                 else if (unlikely(!skb))
3592                         goto unlock;
3593         }
3594 
3595         rx_handler = rcu_dereference(skb->dev->rx_handler);
3596         if (rx_handler) {
3597                 if (pt_prev) {
3598                         ret = deliver_skb(skb, pt_prev, orig_dev);
3599                         pt_prev = NULL;
3600                 }
3601                 switch (rx_handler(&skb)) {
3602                 case RX_HANDLER_CONSUMED:
3603                         ret = NET_RX_SUCCESS;
3604                         goto unlock;
3605                 case RX_HANDLER_ANOTHER:
3606                         goto another_round;
3607                 case RX_HANDLER_EXACT:
3608                         deliver_exact = true;
3609                 case RX_HANDLER_PASS:
3610                         break;
3611                 default:
3612                         BUG();
3613                 }
3614         }
3615 
3616         if (unlikely(vlan_tx_tag_present(skb))) {
3617                 if (vlan_tx_tag_get_id(skb))
3618                         skb->pkt_type = PACKET_OTHERHOST;
3619                 /* Note: we might in the future use prio bits
3620                  * and set skb->priority like in vlan_do_receive()
3621                  * For the time being, just ignore Priority Code Point
3622                  */
3623                 skb->vlan_tci = 0;
3624         }
3625 
3626         /* deliver only exact match when indicated */
3627         null_or_dev = deliver_exact ? skb->dev : NULL;
3628 
3629         type = skb->protocol;
3630         list_for_each_entry_rcu(ptype,
3631                         &ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
3632                 if (ptype->type == type &&
3633                     (ptype->dev == null_or_dev || ptype->dev == skb->dev ||
3634                      ptype->dev == orig_dev)) {
3635                         if (pt_prev)
3636                                 ret = deliver_skb(skb, pt_prev, orig_dev);
3637                         pt_prev = ptype;
3638                 }
3639         }
3640 
3641         if (pt_prev) {
3642                 if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
3643                         goto drop;
3644                 else
3645                         ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
3646         } else {
3647 drop:
3648                 atomic_long_inc(&skb->dev->rx_dropped);
3649                 kfree_skb(skb);
3650                 /* Jamal, now you will not able to escape explaining
3651                  * me how you were going to use this. :-)
3652                  */
3653                 ret = NET_RX_DROP;
3654         }
3655 
3656 unlock:
3657         rcu_read_unlock();
3658 out:
3659         return ret;
3660 }
3661 
3662 static int __netif_receive_skb(struct sk_buff *skb)
3663 {
3664         int ret;
3665 
3666         if (sk_memalloc_socks() && skb_pfmemalloc(skb)) {
3667                 unsigned long pflags = current->flags;
3668 
3669                 /*
3670                  * PFMEMALLOC skbs are special, they should
3671                  * - be delivered to SOCK_MEMALLOC sockets only
3672                  * - stay away from userspace
3673                  * - have bounded memory usage
3674                  *
3675                  * Use PF_MEMALLOC as this saves us from propagating the allocation
3676                  * context down to all allocation sites.
3677                  */
3678                 current->flags |= PF_MEMALLOC;
3679                 ret = __netif_receive_skb_core(skb, true);
3680                 tsk_restore_flags(current, pflags, PF_MEMALLOC);
3681         } else
3682                 ret = __netif_receive_skb_core(skb, false);
3683 
3684         return ret;
3685 }
3686 
3687 static int netif_receive_skb_internal(struct sk_buff *skb)
3688 {
3689         net_timestamp_check(netdev_tstamp_prequeue, skb);
3690 
3691         if (skb_defer_rx_timestamp(skb))
3692                 return NET_RX_SUCCESS;
3693 
3694 #ifdef CONFIG_RPS
3695         if (static_key_false(&rps_needed)) {
3696                 struct rps_dev_flow voidflow, *rflow = &voidflow;
3697                 int cpu, ret;
3698 
3699                 rcu_read_lock();
3700 
3701                 cpu = get_rps_cpu(skb->dev, skb, &rflow);
3702 
3703                 if (cpu >= 0) {
3704                         ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
3705                         rcu_read_unlock();
3706                         return ret;
3707                 }
3708                 rcu_read_unlock();
3709         }
3710 #endif
3711         return __netif_receive_skb(skb);
3712 }
3713 
3714 /**
3715  *      netif_receive_skb - process receive buffer from network
3716  *      @skb: buffer to process
3717  *
3718  *      netif_receive_skb() is the main receive data processing function.
3719  *      It always succeeds. The buffer may be dropped during processing
3720  *      for congestion control or by the protocol layers.
3721  *
3722  *      This function may only be called from softirq context and interrupts
3723  *      should be enabled.
3724  *
3725  *      Return values (usually ignored):
3726  *      NET_RX_SUCCESS: no congestion
3727  *      NET_RX_DROP: packet was dropped
3728  */
3729 int netif_receive_skb(struct sk_buff *skb)
3730 {
3731         trace_netif_receive_skb_entry(skb);
3732 
3733         return netif_receive_skb_internal(skb);
3734 }
3735 EXPORT_SYMBOL(netif_receive_skb);
3736 
3737 /* Network device is going away, flush any packets still pending
3738  * Called with irqs disabled.
3739  */
3740 static void flush_backlog(void *arg)
3741 {
3742         struct net_device *dev = arg;
3743         struct softnet_data *sd = &__get_cpu_var(softnet_data);
3744         struct sk_buff *skb, *tmp;
3745 
3746         rps_lock(sd);
3747         skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
3748                 if (skb->dev == dev) {
3749                         __skb_unlink(skb, &sd->input_pkt_queue);
3750                         kfree_skb(skb);
3751                         input_queue_head_incr(sd);
3752                 }
3753         }
3754         rps_unlock(sd);
3755 
3756         skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
3757                 if (skb->dev == dev) {
3758                         __skb_unlink(skb, &sd->process_queue);
3759                         kfree_skb(skb);
3760                         input_queue_head_incr(sd);
3761                 }
3762         }
3763 }
3764 
3765 static int napi_gro_complete(struct sk_buff *skb)
3766 {
3767         struct packet_offload *ptype;
3768         __be16 type = skb->protocol;
3769         struct list_head *head = &offload_base;
3770         int err = -ENOENT;
3771 
3772         BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
3773 
3774         if (NAPI_GRO_CB(skb)->count == 1) {
3775                 skb_shinfo(skb)->gso_size = 0;
3776                 goto out;
3777         }
3778 
3779         rcu_read_lock();
3780         list_for_each_entry_rcu(ptype, head, list) {
3781                 if (ptype->type != type || !ptype->callbacks.gro_complete)
3782                         continue;
3783 
3784                 err = ptype->callbacks.gro_complete(skb, 0);
3785                 break;
3786         }
3787         rcu_read_unlock();
3788 
3789         if (err) {
3790                 WARN_ON(&ptype->list == head);
3791                 kfree_skb(skb);
3792                 return NET_RX_SUCCESS;
3793         }
3794 
3795 out:
3796         return netif_receive_skb_internal(skb);
3797 }
3798 
3799 /* napi->gro_list contains packets ordered by age.
3800  * youngest packets at the head of it.
3801  * Complete skbs in reverse order to reduce latencies.
3802  */
3803 void napi_gro_flush(struct napi_struct *napi, bool flush_old)
3804 {
3805         struct sk_buff *skb, *prev = NULL;
3806 
3807         /* scan list and build reverse chain */
3808         for (skb = napi->gro_list; skb != NULL; skb = skb->next) {
3809                 skb->prev = prev;
3810                 prev = skb;
3811         }
3812 
3813         for (skb = prev; skb; skb = prev) {
3814                 skb->next = NULL;
3815 
3816                 if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
3817                         return;
3818 
3819                 prev = skb->prev;
3820                 napi_gro_complete(skb);
3821                 napi->gro_count--;
3822         }
3823 
3824         napi->gro_list = NULL;
3825 }
3826 EXPORT_SYMBOL(napi_gro_flush);
3827 
3828 static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb)
3829 {
3830         struct sk_buff *p;
3831         unsigned int maclen = skb->dev->hard_header_len;
3832         u32 hash = skb_get_hash_raw(skb);
3833 
3834         for (p = napi->gro_list; p; p = p->next) {
3835                 unsigned long diffs;
3836 
3837                 NAPI_GRO_CB(p)->flush = 0;
3838 
3839                 if (hash != skb_get_hash_raw(p)) {
3840                         NAPI_GRO_CB(p)->same_flow = 0;
3841                         continue;
3842                 }
3843 
3844                 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
3845                 diffs |= p->vlan_tci ^ skb->vlan_tci;
3846                 if (maclen == ETH_HLEN)
3847                         diffs |= compare_ether_header(skb_mac_header(p),
3848                                                       skb_gro_mac_header(skb));
3849                 else if (!diffs)
3850                         diffs = memcmp(skb_mac_header(p),
3851                                        skb_gro_mac_header(skb),
3852                                        maclen);
3853                 NAPI_GRO_CB(p)->same_flow = !diffs;
3854         }
3855 }
3856 
3857 static void skb_gro_reset_offset(struct sk_buff *skb)
3858 {
3859         const struct skb_shared_info *pinfo = skb_shinfo(skb);
3860         const skb_frag_t *frag0 = &pinfo->frags[0];
3861 
3862         NAPI_GRO_CB(skb)->data_offset = 0;
3863         NAPI_GRO_CB(skb)->frag0 = NULL;
3864         NAPI_GRO_CB(skb)->frag0_len = 0;
3865 
3866         if (skb_mac_header(skb) == skb_tail_pointer(skb) &&
3867             pinfo->nr_frags &&
3868             !PageHighMem(skb_frag_page(frag0))) {
3869                 NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0);
3870                 NAPI_GRO_CB(skb)->frag0_len = skb_frag_size(frag0);
3871         }
3872 }
3873 
3874 static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
3875 {
3876         struct sk_buff **pp = NULL;
3877         struct packet_offload *ptype;
3878         __be16 type = skb->protocol;
3879         struct list_head *head = &offload_base;
3880         int same_flow;
3881         enum gro_result ret;
3882 
3883         if (!(skb->dev->features & NETIF_F_GRO) || netpoll_rx_on(skb))
3884                 goto normal;
3885 
3886         if (skb_is_gso(skb) || skb_has_frag_list(skb))
3887                 goto normal;
3888 
3889         skb_gro_reset_offset(skb);
3890         gro_list_prepare(napi, skb);
3891         NAPI_GRO_CB(skb)->csum = skb->csum; /* Needed for CHECKSUM_COMPLETE */
3892 
3893         rcu_read_lock();
3894         list_for_each_entry_rcu(ptype, head, list) {
3895                 if (ptype->type != type || !ptype->callbacks.gro_receive)
3896                         continue;
3897 
3898                 skb_set_network_header(skb, skb_gro_offset(skb));
3899                 skb_reset_mac_len(skb);
3900                 NAPI_GRO_CB(skb)->same_flow = 0;
3901                 NAPI_GRO_CB(skb)->flush = 0;
3902                 NAPI_GRO_CB(skb)->free = 0;
3903                 NAPI_GRO_CB(skb)->udp_mark = 0;
3904 
3905                 pp = ptype->callbacks.gro_receive(&napi->gro_list, skb);
3906                 break;
3907         }
3908         rcu_read_unlock();
3909 
3910         if (&ptype->list == head)
3911                 goto normal;
3912 
3913         same_flow = NAPI_GRO_CB(skb)->same_flow;
3914         ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;
3915 
3916         if (pp) {
3917                 struct sk_buff *nskb = *pp;
3918 
3919                 *pp = nskb->next;
3920                 nskb->next = NULL;
3921                 napi_gro_complete(nskb);
3922                 napi->gro_count--;
3923         }
3924 
3925         if (same_flow)
3926                 goto ok;
3927 
3928         if (NAPI_GRO_CB(skb)->flush)
3929                 goto normal;
3930 
3931         if (unlikely(napi->gro_count >= MAX_GRO_SKBS)) {
3932                 struct sk_buff *nskb = napi->gro_list;
3933 
3934                 /* locate the end of the list to select the 'oldest' flow */
3935                 while (nskb->next) {
3936                         pp = &nskb->next;
3937                         nskb = *pp;
3938                 }
3939                 *pp = NULL;
3940                 nskb->next = NULL;
3941                 napi_gro_complete(nskb);
3942         } else {
3943                 napi->gro_count++;
3944         }
3945         NAPI_GRO_CB(skb)->count = 1;
3946         NAPI_GRO_CB(skb)->age = jiffies;
3947         skb_shinfo(skb)->gso_size = skb_gro_len(skb);
3948         skb->next = napi->gro_list;
3949         napi->gro_list = skb;
3950         ret = GRO_HELD;
3951 
3952 pull:
3953         if (skb_headlen(skb) < skb_gro_offset(skb)) {
3954                 int grow = skb_gro_offset(skb) - skb_headlen(skb);
3955 
3956                 BUG_ON(skb->end - skb->tail < grow);
3957 
3958                 memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow);
3959 
3960                 skb->tail += grow;
3961                 skb->data_len -= grow;
3962 
3963                 skb_shinfo(skb)->frags[0].page_offset += grow;
3964                 skb_frag_size_sub(&skb_shinfo(skb)->frags[0], grow);
3965 
3966                 if (unlikely(!skb_frag_size(&skb_shinfo(skb)->frags[0]))) {
3967                         skb_frag_unref(skb, 0);
3968                         memmove(skb_shinfo(skb)->frags,
3969                                 skb_shinfo(skb)->frags + 1,
3970                                 --skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
3971                 }
3972         }
3973 
3974 ok:
3975         return ret;
3976 
3977 normal:
3978         ret = GRO_NORMAL;
3979         goto pull;
3980 }
3981 
3982 struct packet_offload *gro_find_receive_by_type(__be16 type)
3983 {
3984         struct list_head *offload_head = &offload_base;
3985         struct packet_offload *ptype;
3986 
3987         list_for_each_entry_rcu(ptype, offload_head, list) {
3988                 if (ptype->type != type || !ptype->callbacks.gro_receive)
3989                         continue;
3990                 return ptype;
3991         }
3992         return NULL;
3993 }
3994 EXPORT_SYMBOL(gro_find_receive_by_type);
3995 
3996 struct packet_offload *gro_find_complete_by_type(__be16 type)
3997 {
3998         struct list_head *offload_head = &offload_base;
3999         struct packet_offload *ptype;
4000 
4001         list_for_each_entry_rcu(ptype, offload_head, list) {
4002                 if (ptype->type != type || !ptype->callbacks.gro_complete)
4003                         continue;
4004                 return ptype;
4005         }
4006         return NULL;
4007 }
4008 EXPORT_SYMBOL(gro_find_complete_by_type);
4009 
4010 static gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
4011 {
4012         switch (ret) {
4013         case GRO_NORMAL:
4014                 if (netif_receive_skb_internal(skb))
4015                         ret = GRO_DROP;
4016                 break;
4017 
4018         case GRO_DROP:
4019                 kfree_skb(skb);
4020                 break;
4021 
4022         case GRO_MERGED_FREE:
4023                 if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
4024                         kmem_cache_free(skbuff_head_cache, skb);
4025                 else
4026                         __kfree_skb(skb);
4027                 break;
4028 
4029         case GRO_HELD:
4030         case GRO_MERGED:
4031                 break;
4032         }
4033 
4034         return ret;
4035 }
4036 
4037 gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
4038 {
4039         trace_napi_gro_receive_entry(skb);
4040 
4041         return napi_skb_finish(dev_gro_receive(napi, skb), skb);
4042 }
4043 EXPORT_SYMBOL(napi_gro_receive);
4044 
4045 static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
4046 {
4047         __skb_pull(skb, skb_headlen(skb));
4048         /* restore the reserve we had after netdev_alloc_skb_ip_align() */
4049         skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb));
4050         skb->vlan_tci = 0;
4051         skb->dev = napi->dev;
4052         skb->skb_iif = 0;
4053 
4054         napi->skb = skb;
4055 }
4056 
4057 struct sk_buff *napi_get_frags(struct napi_struct *napi)
4058 {
4059         struct sk_buff *skb = napi->skb;
4060 
4061         if (!skb) {
4062                 skb = netdev_alloc_skb_ip_align(napi->dev, GRO_MAX_HEAD);
4063                 napi->skb = skb;
4064         }
4065         return skb;
4066 }
4067 EXPORT_SYMBOL(napi_get_frags);
4068 
4069 static gro_result_t napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb,
4070                                gro_result_t ret)
4071 {
4072         switch (ret) {
4073         case GRO_NORMAL:
4074                 if (netif_receive_skb_internal(skb))
4075                         ret = GRO_DROP;
4076                 break;
4077 
4078         case GRO_DROP:
4079         case GRO_MERGED_FREE:
4080                 napi_reuse_skb(napi, skb);
4081                 break;
4082 
4083         case GRO_HELD:
4084         case GRO_MERGED:
4085                 break;
4086         }
4087 
4088         return ret;
4089 }
4090 
4091 static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
4092 {
4093         struct sk_buff *skb = napi->skb;
4094 
4095         napi->skb = NULL;
4096 
4097         if (unlikely(!pskb_may_pull(skb, sizeof(struct ethhdr)))) {
4098                 napi_reuse_skb(napi, skb);
4099                 return NULL;
4100         }
4101         skb->protocol = eth_type_trans(skb, skb->dev);
4102 
4103         return skb;
4104 }
4105 
4106 gro_result_t napi_gro_frags(struct napi_struct *napi)
4107 {
4108         struct sk_buff *skb = napi_frags_skb(napi);
4109 
4110         if (!skb)
4111                 return GRO_DROP;
4112 
4113         trace_napi_gro_frags_entry(skb);
4114 
4115         return napi_frags_finish(napi, skb, dev_gro_receive(napi, skb));
4116 }
4117 EXPORT_SYMBOL(napi_gro_frags);
4118 
4119 /*
4120  * net_rps_action_and_irq_enable sends any pending IPI's for rps.
4121  * Note: called with local irq disabled, but exits with local irq enabled.
4122  */
4123 static void net_rps_action_and_irq_enable(struct softnet_data *sd)
4124 {
4125 #ifdef CONFIG_RPS
4126         struct softnet_data *remsd = sd->rps_ipi_list;
4127 
4128         if (remsd) {
4129                 sd->rps_ipi_list = NULL;
4130 
4131                 local_irq_enable();
4132 
4133                 /* Send pending IPI's to kick RPS processing on remote cpus. */
4134                 while (remsd) {
4135                         struct softnet_data *next = remsd->rps_ipi_next;
4136 
4137                         if (cpu_online(remsd->cpu))
4138                                 __smp_call_function_single(remsd->cpu,
4139                                                            &remsd->csd, 0);
4140                         remsd = next;
4141                 }
4142         } else
4143 #endif
4144                 local_irq_enable();
4145 }
4146 
4147 static int process_backlog(struct napi_struct *napi, int quota)
4148 {
4149         int work = 0;
4150         struct softnet_data *sd = container_of(napi, struct softnet_data, backlog);
4151 
4152 #ifdef CONFIG_RPS
4153         /* Check if we have pending ipi, its better to send them now,
4154          * not waiting net_rx_action() end.
4155          */
4156         if (sd->rps_ipi_list) {
4157                 local_irq_disable();
4158                 net_rps_action_and_irq_enable(sd);
4159         }
4160 #endif
4161         napi->weight = weight_p;
4162         local_irq_disable();
4163         while (work < quota) {
4164                 struct sk_buff *skb;
4165                 unsigned int qlen;
4166 
4167                 while ((skb = __skb_dequeue(&sd->process_queue))) {
4168                         local_irq_enable();
4169                         __netif_receive_skb(skb);
4170                         local_irq_disable();
4171                         input_queue_head_incr(sd);
4172                         if (++work >= quota) {
4173                                 local_irq_enable();
4174                                 return work;
4175                         }
4176                 }
4177 
4178                 rps_lock(sd);
4179                 qlen = skb_queue_len(&sd->input_pkt_queue);
4180                 if (qlen)
4181                         skb_queue_splice_tail_init(&sd->input_pkt_queue,
4182                                                    &sd->process_queue);
4183 
4184                 if (qlen < quota - work) {
4185                         /*
4186                          * Inline a custom version of __napi_complete().
4187                          * only current cpu owns and manipulates this napi,
4188                          * and NAPI_STATE_SCHED is the only possible flag set on backlog.
4189                          * we can use a plain write instead of clear_bit(),
4190                          * and we dont need an smp_mb() memory barrier.
4191                          */
4192                         list_del(&napi->poll_list);
4193                         napi->state = 0;
4194 
4195                         quota = work + qlen;
4196                 }
4197                 rps_unlock(sd);
4198         }
4199         local_irq_enable();
4200 
4201         return work;
4202 }
4203 
4204 /**
4205  * __napi_schedule - schedule for receive
4206  * @n: entry to schedule
4207  *
4208  * The entry's receive function will be scheduled to run
4209  */
4210 void __napi_schedule(struct napi_struct *n)
4211 {
4212         unsigned long flags;
4213 
4214         local_irq_save(flags);
4215         ____napi_schedule(&__get_cpu_var(softnet_data), n);
4216         local_irq_restore(flags);
4217 }
4218 EXPORT_SYMBOL(__napi_schedule);
4219 
4220 void __napi_complete(struct napi_struct *n)
4221 {
4222         BUG_ON(!test_bit(NAPI_STATE_SCHED, &n->state));
4223         BUG_ON(n->gro_list);
4224 
4225         list_del(&n->poll_list);
4226         smp_mb__before_clear_bit();
4227         clear_bit(NAPI_STATE_SCHED, &n->state);
4228 }
4229 EXPORT_SYMBOL(__napi_complete);
4230 
4231 void napi_complete(struct napi_struct *n)
4232 {
4233         unsigned long flags;
4234 
4235         /*
4236          * don't let napi dequeue from the cpu poll list
4237          * just in case its running on a different cpu
4238          */
4239         if (unlikely(test_bit(NAPI_STATE_NPSVC, &n->state)))
4240                 return;
4241 
4242         napi_gro_flush(n, false);
4243         local_irq_save(flags);
4244         __napi_complete(n);
4245         local_irq_restore(flags);
4246 }
4247 EXPORT_SYMBOL(napi_complete);
4248 
4249 /* must be called under rcu_read_lock(), as we dont take a reference */
4250 struct napi_struct *napi_by_id(unsigned int napi_id)
4251 {
4252         unsigned int hash = napi_id % HASH_SIZE(napi_hash);
4253         struct napi_struct *napi;
4254 
4255         hlist_for_each_entry_rcu(napi, &napi_hash[hash], napi_hash_node)
4256                 if (napi->napi_id == napi_id)
4257                         return napi;
4258 
4259         return NULL;
4260 }
4261 EXPORT_SYMBOL_GPL(napi_by_id);
4262 
4263 void napi_hash_add(struct napi_struct *napi)
4264 {
4265         if (!test_and_set_bit(NAPI_STATE_HASHED, &napi->state)) {
4266 
4267                 spin_lock(&napi_hash_lock);
4268 
4269                 /* 0 is not a valid id, we also skip an id that is taken
4270                  * we expect both events to be extremely rare
4271                  */
4272                 napi->napi_id = 0;
4273                 while (!napi->napi_id) {
4274                         napi->napi_id = ++napi_gen_id;
4275                         if (napi_by_id(napi->napi_id))
4276                                 napi->napi_id = 0;
4277                 }
4278 
4279                 hlist_add_head_rcu(&napi->napi_hash_node,
4280                         &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]);
4281 
4282                 spin_unlock(&napi_hash_lock);
4283         }
4284 }
4285 EXPORT_SYMBOL_GPL(napi_hash_add);
4286 
4287 /* Warning : caller is responsible to make sure rcu grace period
4288  * is respected before freeing memory containing @napi
4289  */
4290 void napi_hash_del(struct napi_struct *napi)
4291 {
4292         spin_lock(&napi_hash_lock);
4293 
4294         if (test_and_clear_bit(NAPI_STATE_HASHED, &napi->state))
4295                 hlist_del_rcu(&napi->napi_hash_node);
4296 
4297         spin_unlock(&napi_hash_lock);
4298 }
4299 EXPORT_SYMBOL_GPL(napi_hash_del);
4300 
4301 void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
4302                     int (*poll)(struct napi_struct *, int), int weight)
4303 {
4304         INIT_LIST_HEAD(&napi->poll_list);
4305         napi->gro_count = 0;
4306         napi->gro_list = NULL;
4307         napi->skb = NULL;
4308         napi->poll = poll;
4309         if (weight > NAPI_POLL_WEIGHT)
4310                 pr_err_once("netif_napi_add() called with weight %d on device %s\n",
4311                             weight, dev->name);
4312         napi->weight = weight;
4313         list_add(&napi->dev_list, &dev->napi_list);
4314         napi->dev = dev;
4315 #ifdef CONFIG_NETPOLL
4316         spin_lock_init(&napi->poll_lock);
4317         napi->poll_owner = -1;
4318 #endif
4319         set_bit(NAPI_STATE_SCHED, &napi->state);
4320 }
4321 EXPORT_SYMBOL(netif_napi_add);
4322 
4323 void netif_napi_del(struct napi_struct *napi)
4324 {
4325         list_del_init(&napi->dev_list);
4326         napi_free_frags(napi);
4327 
4328         kfree_skb_list(napi->gro_list);
4329         napi->gro_list = NULL;
4330         napi->gro_count = 0;
4331 }
4332 EXPORT_SYMBOL(netif_napi_del);
4333 
4334 static void net_rx_action(struct softirq_action *h)
4335 {
4336         struct softnet_data *sd = &__get_cpu_var(softnet_data);
4337         unsigned long time_limit = jiffies + 2;
4338         int budget = netdev_budget;
4339         void *have;
4340 
4341         local_irq_disable();
4342 
4343         while (!list_empty(&sd->poll_list)) {
4344                 struct napi_struct *n;
4345                 int work, weight;
4346 
4347                 /* If softirq window is exhuasted then punt.
4348                  * Allow this to run for 2 jiffies since which will allow
4349                  * an average latency of 1.5/HZ.
4350                  */
4351                 if (unlikely(budget <= 0 || time_after_eq(jiffies, time_limit)))
4352                         goto softnet_break;
4353 
4354                 local_irq_enable();
4355 
4356                 /* Even though interrupts have been re-enabled, this
4357                  * access is safe because interrupts can only add new
4358                  * entries to the tail of this list, and only ->poll()
4359                  * calls can remove this head entry from the list.
4360                  */
4361                 n = list_first_entry(&sd->poll_list, struct napi_struct, poll_list);
4362 
4363                 have = netpoll_poll_lock(n);
4364 
4365                 weight = n->weight;
4366 
4367                 /* This NAPI_STATE_SCHED test is for avoiding a race
4368                  * with netpoll's poll_napi().  Only the entity which
4369                  * obtains the lock and sees NAPI_STATE_SCHED set will
4370                  * actually make the ->poll() call.  Therefore we avoid
4371                  * accidentally calling ->poll() when NAPI is not scheduled.
4372                  */
4373                 work = 0;
4374                 if (test_bit(NAPI_STATE_SCHED, &n->state)) {
4375                         work = n->poll(n, weight);
4376                         trace_napi_poll(n);
4377                 }
4378 
4379                 WARN_ON_ONCE(work > weight);
4380 
4381                 budget -= work;
4382 
4383                 local_irq_disable();
4384 
4385                 /* Drivers must not modify the NAPI state if they
4386                  * consume the entire weight.  In such cases this code
4387                  * still "owns" the NAPI instance and therefore can
4388                  * move the instance around on the list at-will.
4389                  */
4390                 if (unlikely(work == weight)) {
4391                         if (unlikely(napi_disable_pending(n))) {
4392                                 local_irq_enable();
4393                                 napi_complete(n);
4394                                 local_irq_disable();
4395                         } else {
4396                                 if (n->gro_list) {
4397                                         /* flush too old packets
4398                                          * If HZ < 1000, flush all packets.
4399                                          */
4400                                         local_irq_enable();
4401                                         napi_gro_flush(n, HZ >= 1000);
4402                                         local_irq_disable();
4403                                 }
4404                                 list_move_tail(&n->poll_list, &sd->poll_list);
4405                         }
4406                 }
4407 
4408                 netpoll_poll_unlock(have);
4409         }
4410 out:
4411         net_rps_action_and_irq_enable(sd);
4412 
4413 #ifdef CONFIG_NET_DMA
4414         /*
4415          * There may not be any more sk_buffs coming right now, so push
4416          * any pending DMA copies to hardware
4417          */
4418         dma_issue_pending_all();
4419 #endif
4420 
4421         return;
4422 
4423 softnet_break:
4424         sd->time_squeeze++;
4425         __raise_softirq_irqoff(NET_RX_SOFTIRQ);
4426         goto out;
4427 }
4428 
4429 struct netdev_adjacent {
4430         struct net_device *dev;
4431 
4432         /* upper master flag, there can only be one master device per list */
4433         bool master;
4434 
4435         /* counter for the number of times this device was added to us */
4436         u16 ref_nr;
4437 
4438         /* private field for the users */
4439         void *private;
4440 
4441         struct list_head list;
4442         struct rcu_head rcu;
4443 };
4444 
4445 static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
4446                                                  struct net_device *adj_dev,
4447                                                  struct list_head *adj_list)
4448 {
4449         struct netdev_adjacent *adj;
4450 
4451         list_for_each_entry(adj, adj_list, list) {
4452                 if (adj->dev == adj_dev)
4453                         return adj;
4454         }
4455         return NULL;
4456 }
4457 
4458 /**
4459  * netdev_has_upper_dev - Check if device is linked to an upper device
4460  * @dev: device
4461  * @upper_dev: upper device to check
4462  *
4463  * Find out if a device is linked to specified upper device and return true
4464  * in case it is. Note that this checks only immediate upper device,
4465  * not through a complete stack of devices. The caller must hold the RTNL lock.
4466  */
4467 bool netdev_has_upper_dev(struct net_device *dev,
4468                           struct net_device *upper_dev)
4469 {
4470         ASSERT_RTNL();
4471 
4472         return __netdev_find_adj(dev, upper_dev, &dev->all_adj_list.upper);
4473 }
4474 EXPORT_SYMBOL(netdev_has_upper_dev);
4475 
4476 /**
4477  * netdev_has_any_upper_dev - Check if device is linked to some device
4478  * @dev: device
4479  *
4480  * Find out if a device is linked to an upper device and return true in case
4481  * it is. The caller must hold the RTNL lock.
4482  */
4483 static bool netdev_has_any_upper_dev(struct net_device *dev)
4484 {
4485         ASSERT_RTNL();
4486 
4487         return !list_empty(&dev->all_adj_list.upper);
4488 }
4489 
4490 /**
4491  * netdev_master_upper_dev_get - Get master upper device
4492  * @dev: device
4493  *
4494  * Find a master upper device and return pointer to it or NULL in case
4495  * it's not there. The caller must hold the RTNL lock.
4496  */
4497 struct net_device *netdev_master_upper_dev_get(struct net_device *dev)
4498 {
4499         struct netdev_adjacent *upper;
4500 
4501         ASSERT_RTNL();
4502 
4503         if (list_empty(&dev->adj_list.upper))
4504                 return NULL;
4505 
4506         upper = list_first_entry(&dev->adj_list.upper,
4507                                  struct netdev_adjacent, list);
4508         if (likely(upper->master))
4509                 return upper->dev;
4510         return NULL;
4511 }
4512 EXPORT_SYMBOL(netdev_master_upper_dev_get);
4513 
4514 void *netdev_adjacent_get_private(struct list_head *adj_list)
4515 {
4516         struct netdev_adjacent *adj;
4517 
4518         adj = list_entry(adj_list, struct netdev_adjacent, list);
4519 
4520         return adj->private;
4521 }
4522 EXPORT_SYMBOL(netdev_adjacent_get_private);
4523 
4524 /**
4525  * netdev_all_upper_get_next_dev_rcu - Get the next dev from upper list
4526  * @dev: device
4527  * @iter: list_head ** of the current position
4528  *
4529  * Gets the next device from the dev's upper list, starting from iter
4530  * position. The caller must hold RCU read lock.
4531  */
4532 struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev,
4533                                                      struct list_head **iter)
4534 {
4535         struct netdev_adjacent *upper;
4536 
4537         WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());
4538 
4539         upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
4540 
4541         if (&upper->list == &dev->all_adj_list.upper)
4542                 return NULL;
4543 
4544         *iter = &upper->list;
4545 
4546         return upper->dev;
4547 }
4548 EXPORT_SYMBOL(netdev_all_upper_get_next_dev_rcu);
4549 
4550 /**
4551  * netdev_lower_get_next_private - Get the next ->private from the
4552  *                                 lower neighbour list
4553  * @dev: device
4554  * @iter: list_head ** of the current position
4555  *
4556  * Gets the next netdev_adjacent->private from the dev's lower neighbour
4557  * list, starting from iter position. The caller must hold either hold the
4558  * RTNL lock or its own locking that guarantees that the neighbour lower
4559  * list will remain unchainged.
4560  */
4561 void *netdev_lower_get_next_private(struct net_device *dev,
4562                                     struct list_head **iter)
4563 {
4564         struct netdev_adjacent *lower;
4565 
4566         lower = list_entry(*iter, struct netdev_adjacent, list);
4567 
4568         if (&lower->list == &dev->adj_list.lower)
4569                 return NULL;
4570 
4571         if (iter)
4572                 *iter = lower->list.next;
4573 
4574         return lower->private;
4575 }
4576 EXPORT_SYMBOL(netdev_lower_get_next_private);
4577 
4578 /**
4579  * netdev_lower_get_next_private_rcu - Get the next ->private from the
4580  *                                     lower neighbour list, RCU
4581  *                                     variant
4582  * @dev: device
4583  * @iter: list_head ** of the current position
4584  *
4585  * Gets the next netdev_adjacent->private from the dev's lower neighbour
4586  * list, starting from iter position. The caller must hold RCU read lock.
4587  */
4588 void *netdev_lower_get_next_private_rcu(struct net_device *dev,
4589                                         struct list_head **iter)
4590 {
4591         struct netdev_adjacent *lower;
4592 
4593         WARN_ON_ONCE(!rcu_read_lock_held());
4594 
4595         lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);
4596 
4597         if (&lower->list == &dev->adj_list.lower)
4598                 return NULL;
4599 
4600         if (iter)
4601                 *iter = &lower->list;
4602 
4603         return lower->private;
4604 }
4605 EXPORT_SYMBOL(netdev_lower_get_next_private_rcu);
4606 
4607 /**
4608  * netdev_lower_get_first_private_rcu - Get the first ->private from the
4609  *                                     lower neighbour list, RCU
4610  *                                     variant
4611  * @dev: device
4612  *
4613  * Gets the first netdev_adjacent->private from the dev's lower neighbour
4614  * list. The caller must hold RCU read lock.
4615  */
4616 void *netdev_lower_get_first_private_rcu(struct net_device *dev)
4617 {
4618         struct netdev_adjacent *lower;
4619 
4620         lower = list_first_or_null_rcu(&dev->adj_list.lower,
4621                         struct netdev_adjacent, list);
4622         if (lower)
4623                 return lower->private;
4624         return NULL;
4625 }
4626 EXPORT_SYMBOL(netdev_lower_get_first_private_rcu);
4627 
4628 /**
4629  * netdev_master_upper_dev_get_rcu - Get master upper device
4630  * @dev: device
4631  *
4632  * Find a master upper device and return pointer to it or NULL in case
4633  * it's not there. The caller must hold the RCU read lock.
4634  */
4635 struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev)
4636 {
4637         struct netdev_adjacent *upper;
4638 
4639         upper = list_first_or_null_rcu(&dev->adj_list.upper,
4640                                        struct netdev_adjacent, list);
4641         if (upper && likely(upper->master))
4642                 return upper->dev;
4643         return NULL;
4644 }
4645 EXPORT_SYMBOL(netdev_master_upper_dev_get_rcu);
4646 
4647 static int netdev_adjacent_sysfs_add(struct net_device *dev,
4648                               struct net_device *adj_dev,
4649                               struct list_head *dev_list)
4650 {
4651         char linkname[IFNAMSIZ+7];
4652         sprintf(linkname, dev_list == &dev->adj_list.upper ?
4653                 "upper_%s" : "lower_%s", adj_dev->name);
4654         return sysfs_create_link(&(dev->dev.kobj), &(adj_dev->dev.kobj),
4655                                  linkname);
4656 }
4657 static void netdev_adjacent_sysfs_del(struct net_device *dev,
4658                                char *name,
4659                                struct list_head *dev_list)
4660 {
4661         char linkname[IFNAMSIZ+7];
4662         sprintf(linkname, dev_list == &dev->adj_list.upper ?
4663                 "upper_%s" : "lower_%s", name);
4664         sysfs_remove_link(&(dev->dev.kobj), linkname);
4665 }
4666 
4667 #define netdev_adjacent_is_neigh_list(dev, dev_list) \
4668                 (dev_list == &dev->adj_list.upper || \
4669                  dev_list == &dev->adj_list.lower)
4670 
4671 static int __netdev_adjacent_dev_insert(struct net_device *dev,
4672                                         struct net_device *adj_dev,
4673                                         struct list_head *dev_list,
4674                                         void *private, bool master)
4675 {
4676         struct netdev_adjacent *adj;
4677         int ret;
4678 
4679         adj = __netdev_find_adj(dev, adj_dev, dev_list);
4680 
4681         if (adj) {
4682                 adj->ref_nr++;
4683                 return 0;
4684         }
4685 
4686         adj = kmalloc(sizeof(*adj), GFP_KERNEL);
4687         if (!adj)
4688                 return -ENOMEM;
4689 
4690         adj->dev = adj_dev;
4691         adj->master = master;
4692         adj->ref_nr = 1;
4693         adj->private = private;
4694         dev_hold(adj_dev);
4695 
4696         pr_debug("dev_hold for %s, because of link added from %s to %s\n",
4697                  adj_dev->name, dev->name, adj_dev->name);
4698 
4699         if (netdev_adjacent_is_neigh_list(dev, dev_list)) {
4700                 ret = netdev_adjacent_sysfs_add(dev, adj_dev, dev_list);
4701                 if (ret)
4702                         goto free_adj;
4703         }
4704 
4705         /* Ensure that master link is always the first item in list. */
4706         if (master) {
4707                 ret = sysfs_create_link(&(dev->dev.kobj),
4708                                         &(adj_dev->dev.kobj), "master");
4709                 if (ret)
4710                         goto remove_symlinks;
4711 
4712                 list_add_rcu(&adj->list, dev_list);
4713         } else {
4714                 list_add_tail_rcu(&adj->list, dev_list);
4715         }
4716 
4717         return 0;
4718 
4719 remove_symlinks:
4720         if (netdev_adjacent_is_neigh_list(dev, dev_list))
4721                 netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
4722 free_adj:
4723         kfree(adj);
4724         dev_put(adj_dev);
4725 
4726         return ret;
4727 }
4728 
4729 static void __netdev_adjacent_dev_remove(struct net_device *dev,
4730                                          struct net_device *adj_dev,
4731                                          struct list_head *dev_list)
4732 {
4733         struct netdev_adjacent *adj;
4734 
4735         adj = __netdev_find_adj(dev, adj_dev, dev_list);
4736 
4737         if (!adj) {
4738                 pr_err("tried to remove device %s from %s\n",
4739                        dev->name, adj_dev->name);
4740                 BUG();
4741         }
4742 
4743         if (adj->ref_nr > 1) {
4744                 pr_debug("%s to %s ref_nr-- = %d\n", dev->name, adj_dev->name,
4745                          adj->ref_nr-1);
4746                 adj->ref_nr--;
4747                 return;
4748         }
4749 
4750         if (adj->master)
4751                 sysfs_remove_link(&(dev->dev.kobj), "master");
4752 
4753         if (netdev_adjacent_is_neigh_list(dev, dev_list))
4754                 netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
4755 
4756         list_del_rcu(&adj->list);
4757         pr_debug("dev_put for %s, because link removed from %s to %s\n",
4758                  adj_dev->name, dev->name, adj_dev->name);
4759         dev_put(adj_dev);
4760         kfree_rcu(adj, rcu);
4761 }
4762 
4763 static int __netdev_adjacent_dev_link_lists(struct net_device *dev,
4764                                             struct net_device *upper_dev,
4765                                             struct list_head *up_list,
4766                                             struct list_head *down_list,
4767                                             void *private, bool master)
4768 {
4769         int ret;
4770 
4771         ret = __netdev_adjacent_dev_insert(dev, upper_dev, up_list, private,
4772                                            master);
4773         if (ret)
4774                 return ret;
4775 
4776         ret = __netdev_adjacent_dev_insert(upper_dev, dev, down_list, private,
4777                                            false);
4778         if (ret) {
4779                 __netdev_adjacent_dev_remove(dev, upper_dev, up_list);
4780                 return ret;
4781         }
4782 
4783         return 0;
4784 }
4785 
4786 static int __netdev_adjacent_dev_link(struct net_device *dev,
4787                                       struct net_device *upper_dev)
4788 {
4789         return __netdev_adjacent_dev_link_lists(dev, upper_dev,
4790                                                 &dev->all_adj_list.upper,
4791                                                 &upper_dev->all_adj_list.lower,
4792                                                 NULL, false);
4793 }
4794 
4795 static void __netdev_adjacent_dev_unlink_lists(struct net_device *dev,
4796                                                struct net_device *upper_dev,
4797                                                struct list_head *up_list,
4798                                                struct list_head *down_list)
4799 {
4800         __netdev_adjacent_dev_remove(dev, upper_dev, up_list);
4801         __netdev_adjacent_dev_remove(upper_dev, dev, down_list);
4802 }
4803 
4804 static void __netdev_adjacent_dev_unlink(struct net_device *dev,
4805                                          struct net_device *upper_dev)
4806 {
4807         __netdev_adjacent_dev_unlink_lists(dev, upper_dev,
4808                                            &dev->all_adj_list.upper,
4809                                            &upper_dev->all_adj_list.lower);
4810 }
4811 
4812 static int __netdev_adjacent_dev_link_neighbour(struct net_device *dev,
4813                                                 struct net_device *upper_dev,
4814                                                 void *private, bool master)
4815 {
4816         int ret = __netdev_adjacent_dev_link(dev, upper_dev);
4817 
4818         if (ret)
4819                 return ret;
4820 
4821         ret = __netdev_adjacent_dev_link_lists(dev, upper_dev,
4822                                                &dev->adj_list.upper,
4823                                                &upper_dev->adj_list.lower,
4824                                                private, master);
4825         if (ret) {
4826                 __netdev_adjacent_dev_unlink(dev, upper_dev);
4827                 return ret;
4828         }
4829 
4830         return 0;
4831 }
4832 
4833 static void __netdev_adjacent_dev_unlink_neighbour(struct net_device *dev,
4834                                                    struct net_device *upper_dev)
4835 {
4836         __netdev_adjacent_dev_unlink(dev, upper_dev);
4837         __netdev_adjacent_dev_unlink_lists(dev, upper_dev,
4838                                            &dev->adj_list.upper,
4839                                            &upper_dev->adj_list.lower);
4840 }
4841 
4842 static int __netdev_upper_dev_link(struct net_device *dev,
4843                                    struct net_device *upper_dev, bool master,
4844                                    void *private)
4845 {
4846         struct netdev_adjacent *i, *j, *to_i, *to_j;
4847         int ret = 0;
4848 
4849         ASSERT_RTNL();
4850 
4851         if (dev == upper_dev)
4852                 return -EBUSY;
4853 
4854         /* To prevent loops, check if dev is not upper device to upper_dev. */
4855         if (__netdev_find_adj(upper_dev, dev, &upper_dev->all_adj_list.upper))
4856                 return -EBUSY;
4857 
4858         if (__netdev_find_adj(dev, upper_dev, &dev->all_adj_list.upper))
4859                 return -EEXIST;
4860 
4861         if (master && netdev_master_upper_dev_get(dev))
4862                 return -EBUSY;
4863 
4864         ret = __netdev_adjacent_dev_link_neighbour(dev, upper_dev, private,
4865                                                    master);
4866         if (ret)
4867                 return ret;
4868 
4869         /* Now that we linked these devs, make all the upper_dev's
4870          * all_adj_list.upper visible to every dev's all_adj_list.lower an
4871          * versa, and don't forget the devices itself. All of these
4872          * links are non-neighbours.
4873          */
4874         list_for_each_entry(i, &dev->all_adj_list.lower, list) {
4875                 list_for_each_entry(j, &upper_dev->all_adj_list.upper, list) {
4876                         pr_debug("Interlinking %s with %s, non-neighbour\n",
4877                                  i->dev->name, j->dev->name);
4878                         ret = __netdev_adjacent_dev_link(i->dev, j->dev);
4879                         if (ret)
4880                                 goto rollback_mesh;
4881                 }
4882         }
4883 
4884         /* add dev to every upper_dev's upper device */
4885         list_for_each_entry(i, &upper_dev->all_adj_list.upper, list) {
4886                 pr_debug("linking %s's upper device %s with %s\n",
4887                          upper_dev->name, i->dev->name, dev->name);
4888                 ret = __netdev_adjacent_dev_link(dev, i->dev);
4889                 if (ret)
4890                         goto rollback_upper_mesh;
4891         }
4892 
4893         /* add upper_dev to every dev's lower device */
4894         list_for_each_entry(i, &dev->all_adj_list.lower, list) {
4895                 pr_debug("linking %s's lower device %s with %s\n", dev->name,
4896                          i->dev->name, upper_dev->name);
4897                 ret = __netdev_adjacent_dev_link(i->dev, upper_dev);
4898                 if (ret)
4899                         goto rollback_lower_mesh;
4900         }
4901 
4902         call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
4903         return 0;
4904 
4905 rollback_lower_mesh:
4906         to_i = i;
4907         list_for_each_entry(i, &dev->all_adj_list.lower, list) {
4908                 if (i == to_i)
4909                         break;
4910                 __netdev_adjacent_dev_unlink(i->dev, upper_dev);
4911         }
4912 
4913         i = NULL;
4914 
4915 rollback_upper_mesh:
4916         to_i = i;
4917         list_for_each_entry(i, &upper_dev->all_adj_list.upper, list) {
4918                 if (i == to_i)
4919                         break;
4920                 __netdev_adjacent_dev_unlink(dev, i->dev);
4921         }
4922 
4923         i = j = NULL;
4924 
4925 rollback_mesh:
4926         to_i = i;
4927         to_j = j;
4928         list_for_each_entry(i, &dev->all_adj_list.lower, list) {
4929                 list_for_each_entry(j, &upper_dev->all_adj_list.upper, list) {
4930                         if (i == to_i && j == to_j)
4931                                 break;
4932                         __netdev_adjacent_dev_unlink(i->dev, j->dev);
4933                 }
4934                 if (i == to_i)
4935                         break;
4936         }
4937 
4938         __netdev_adjacent_dev_unlink_neighbour(dev, upper_dev);
4939 
4940         return ret;
4941 }
4942 
4943 /**
4944  * netdev_upper_dev_link - Add a link to the upper device
4945  * @dev: device
4946  * @upper_dev: new upper device
4947  *
4948  * Adds a link to device which is upper to this one. The caller must hold
4949  * the RTNL lock. On a failure a negative errno code is returned.
4950  * On success the reference counts are adjusted and the function
4951  * returns zero.
4952  */
4953 int netdev_upper_dev_link(struct net_device *dev,
4954                           struct net_device *upper_dev)
4955 {
4956         return __netdev_upper_dev_link(dev, upper_dev, false, NULL);
4957 }
4958 EXPORT_SYMBOL(netdev_upper_dev_link);
4959 
4960 /**
4961  * netdev_master_upper_dev_link - Add a master link to the upper device
4962  * @dev: device
4963  * @upper_dev: new upper device
4964  *
4965  * Adds a link to device which is upper to this one. In this case, only
4966  * one master upper device can be linked, although other non-master devices
4967  * might be linked as well. The caller must hold the RTNL lock.
4968  * On a failure a negative errno code is returned. On success the reference
4969  * counts are adjusted and the function returns zero.
4970  */
4971 int netdev_master_upper_dev_link(struct net_device *dev,
4972                                  struct net_device *upper_dev)
4973 {
4974         return __netdev_upper_dev_link(dev, upper_dev, true, NULL);
4975 }
4976 EXPORT_SYMBOL(netdev_master_upper_dev_link);
4977 
4978 int netdev_master_upper_dev_link_private(struct net_device *dev,
4979                                          struct net_device *upper_dev,
4980                                          void *private)
4981 {
4982         return __netdev_upper_dev_link(dev, upper_dev, true, private);
4983 }
4984 EXPORT_SYMBOL(netdev_master_upper_dev_link_private);
4985 
4986 /**
4987  * netdev_upper_dev_unlink - Removes a link to upper device
4988  * @dev: device
4989  * @upper_dev: new upper device
4990  *
4991  * Removes a link to device which is upper to this one. The caller must hold
4992  * the RTNL lock.
4993  */
4994 void netdev_upper_dev_unlink(struct net_device *dev,
4995                              struct net_device *upper_dev)
4996 {
4997         struct netdev_adjacent *i, *j;
4998         ASSERT_RTNL();
4999 
5000         __netdev_adjacent_dev_unlink_neighbour(dev, upper_dev);
5001 
5002         /* Here is the tricky part. We must remove all dev's lower
5003          * devices from all upper_dev's upper devices and vice
5004          * versa, to maintain the graph relationship.
5005          */
5006         list_for_each_entry(i, &dev->all_adj_list.lower, list)
5007                 list_for_each_entry(j, &upper_dev->all_adj_list.upper, list)
5008                         __netdev_adjacent_dev_unlink(i->dev, j->dev);
5009 
5010         /* remove also the devices itself from lower/upper device
5011          * list
5012          */
5013         list_for_each_entry(i, &dev->all_adj_list.lower, list)
5014                 __netdev_adjacent_dev_unlink(i->dev, upper_dev);
5015 
5016         list_for_each_entry(i, &upper_dev->all_adj_list.upper, list)
5017                 __netdev_adjacent_dev_unlink(dev, i->dev);
5018 
5019         call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
5020 }
5021 EXPORT_SYMBOL(netdev_upper_dev_unlink);
5022 
5023 void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)
5024 {
5025         struct netdev_adjacent *iter;
5026 
5027         list_for_each_entry(iter, &dev->adj_list.upper, list) {
5028                 netdev_adjacent_sysfs_del(iter->dev, oldname,
5029                                           &iter->dev->adj_list.lower);
5030                 netdev_adjacent_sysfs_add(iter->dev, dev,
5031                                           &iter->dev->adj_list.lower);
5032         }
5033 
5034         list_for_each_entry(iter, &dev->adj_list.lower, list) {
5035                 netdev_adjacent_sysfs_del(iter->dev, oldname,
5036                                           &iter->dev->adj_list.upper);
5037                 netdev_adjacent_sysfs_add(iter->dev, dev,
5038                                           &iter->dev->adj_list.upper);
5039         }
5040 }
5041 
5042 void *netdev_lower_dev_get_private(struct net_device *dev,
5043                                    struct net_device *lower_dev)
5044 {
5045         struct netdev_adjacent *lower;
5046 
5047         if (!lower_dev)
5048                 return NULL;
5049         lower = __netdev_find_adj(dev, lower_dev, &dev->adj_list.lower);
5050         if (!lower)
5051                 return NULL;
5052 
5053         return lower->private;
5054 }
5055 EXPORT_SYMBOL(netdev_lower_dev_get_private);
5056 
5057 static void dev_change_rx_flags(struct net_device *dev, int flags)
5058 {
5059         const struct net_device_ops *ops = dev->netdev_ops;
5060 
5061         if (ops->ndo_change_rx_flags)
5062                 ops->ndo_change_rx_flags(dev, flags);
5063 }
5064 
5065 static int __dev_set_promiscuity(struct net_device *dev, int inc, bool notify)
5066 {
5067         unsigned int old_flags = dev->flags;
5068         kuid_t uid;
5069         kgid_t gid;
5070 
5071         ASSERT_RTNL();
5072 
5073         dev->flags |= IFF_PROMISC;
5074         dev->promiscuity += inc;
5075         if (dev->promiscuity == 0) {
5076                 /*
5077                  * Avoid overflow.
5078                  * If inc causes overflow, untouch promisc and return error.
5079                  */
5080                 if (inc < 0)
5081                         dev->flags &= ~IFF_PROMISC;
5082                 else {
5083                         dev->promiscuity -= inc;
5084                         pr_warn("%s: promiscuity touches roof, set promiscuity failed. promiscuity feature of device might be broken.\n",
5085                                 dev->name);
5086                         return -EOVERFLOW;
5087                 }
5088         }
5089         if (dev->flags != old_flags) {
5090                 pr_info("device %s %s promiscuous mode\n",
5091                         dev->name,
5092                         dev->flags & IFF_PROMISC ? "entered" : "left");
5093                 if (audit_enabled) {
5094                         current_uid_gid(&uid, &gid);
5095                         audit_log(current->audit_context, GFP_ATOMIC,
5096                                 AUDIT_ANOM_PROMISCUOUS,
5097                                 "dev=%s prom=%d old_prom=%d auid=%u uid=%u gid=%u ses=%u",
5098                                 dev->name, (dev->flags & IFF_PROMISC),
5099                                 (old_flags & IFF_PROMISC),
5100                                 from_kuid(&init_user_ns, audit_get_loginuid(current)),
5101                                 from_kuid(&init_user_ns, uid),
5102                                 from_kgid(&init_user_ns, gid),
5103                                 audit_get_sessionid(current));
5104                 }
5105 
5106                 dev_change_rx_flags(dev, IFF_PROMISC);
5107         }
5108         if (notify)
5109                 __dev_notify_flags(dev, old_flags, IFF_PROMISC);
5110         return 0;
5111 }
5112 
5113 /**
5114  *      dev_set_promiscuity     - update promiscuity count on a device
5115  *      @dev: device
5116  *      @inc: modifier
5117  *
5118  *      Add or remove promiscuity from a device. While the count in the device
5119  *      remains above zero the interface remains promiscuous. Once it hits zero
5120  *      the device reverts back to normal filtering operation. A negative inc
5121  *      value is used to drop promiscuity on the device.
5122  *      Return 0 if successful or a negative errno code on error.
5123  */
5124 int dev_set_promiscuity(struct net_device *dev, int inc)
5125 {
5126         unsigned int old_flags = dev->flags;
5127         int err;
5128 
5129         err = __dev_set_promiscuity(dev, inc, true);
5130         if (err < 0)
5131                 return err;
5132         if (dev->flags != old_flags)
5133                 dev_set_rx_mode(dev);
5134         return err;
5135 }
5136 EXPORT_SYMBOL(dev_set_promiscuity);
5137 
5138 static int __dev_set_allmulti(struct net_device *dev, int inc, bool notify)
5139 {
5140         unsigned int old_flags = dev->flags, old_gflags = dev->gflags;
5141 
5142         ASSERT_RTNL();
5143 
5144         dev->flags |= IFF_ALLMULTI;
5145         dev->allmulti += inc;
5146         if (dev->allmulti == 0) {
5147                 /*
5148                  * Avoid overflow.
5149                  * If inc causes overflow, untouch allmulti and return error.
5150                  */
5151                 if (inc < 0)
5152                         dev->flags &= ~IFF_ALLMULTI;
5153                 else {
5154                         dev->allmulti -= inc;
5155                         pr_warn("%s: allmulti touches roof, set allmulti failed. allmulti feature of device might be broken.\n",
5156                                 dev->name);
5157                         return -EOVERFLOW;
5158                 }
5159         }
5160         if (dev->flags ^ old_flags) {
5161                 dev_change_rx_flags(dev, IFF_ALLMULTI);
5162                 dev_set_rx_mode(dev);
5163                 if (notify)
5164                         __dev_notify_flags(dev, old_flags,
5165                                            dev->gflags ^ old_gflags);
5166         }
5167         return 0;
5168 }
5169 
5170 /**
5171  *      dev_set_allmulti        - update allmulti count on a device
5172  *      @dev: device
5173  *      @inc: modifier
5174  *
5175  *      Add or remove reception of all multicast frames to a device. While the
5176  *      count in the device remains above zero the interface remains listening
5177  *      to all interfaces. Once it hits zero the device reverts back to normal
5178  *      filtering operation. A negative @inc value is used to drop the counter
5179  *      when releasing a resource needing all multicasts.
5180  *      Return 0 if successful or a negative errno code on error.
5181  */
5182 
5183 int dev_set_allmulti(struct net_device *dev, int inc)
5184 {
5185         return __dev_set_allmulti(dev, inc, true);
5186 }
5187 EXPORT_SYMBOL(dev_set_allmulti);
5188 
5189 /*
5190  *      Upload unicast and multicast address lists to device and
5191  *      configure RX filtering. When the device doesn't support unicast
5192  *      filtering it is put in promiscuous mode while unicast addresses
5193  *      are present.
5194  */
5195 void __dev_set_rx_mode(struct net_device *dev)
5196 {
5197         const struct net_device_ops *ops = dev->netdev_ops;
5198 
5199         /* dev_open will call this function so the list will stay sane. */
5200         if (!(dev->flags&IFF_UP))
5201                 return;
5202 
5203         if (!netif_device_present(dev))
5204                 return;
5205 
5206         if (!(dev->priv_flags & IFF_UNICAST_FLT)) {
5207                 /* Unicast addresses changes may only happen under the rtnl,
5208                  * therefore calling __dev_set_promiscuity here is safe.
5209                  */
5210                 if (!netdev_uc_empty(dev) && !dev->uc_promisc) {
5211                         __dev_set_promiscuity(dev, 1, false);
5212                         dev->uc_promisc = true;
5213                 } else if (netdev_uc_empty(dev) && dev->uc_promisc) {
5214                         __dev_set_promiscuity(dev, -1, false);
5215                         dev->uc_promisc = false;
5216                 }
5217         }
5218 
5219         if (ops->ndo_set_rx_mode)
5220                 ops->ndo_set_rx_mode(dev);
5221 }
5222 
5223 void dev_set_rx_mode(struct net_device *dev)
5224 {
5225         netif_addr_lock_bh(dev);
5226         __dev_set_rx_mode(dev);
5227         netif_addr_unlock_bh(dev);
5228 }
5229 
5230 /**
5231  *      dev_get_flags - get flags reported to userspace
5232  *      @dev: device
5233  *
5234  *      Get the combination of flag bits exported through APIs to userspace.
5235  */
5236 unsigned int dev_get_flags(const struct net_device *dev)
5237 {
5238         unsigned int flags;
5239 
5240         flags = (dev->flags & ~(IFF_PROMISC |
5241                                 IFF_ALLMULTI |
5242                                 IFF_RUNNING |
5243                                 IFF_LOWER_UP |
5244                                 IFF_DORMANT)) |
5245                 (dev->gflags & (IFF_PROMISC |
5246                                 IFF_ALLMULTI));
5247 
5248         if (netif_running(dev)) {
5249                 if (netif_oper_up(dev))
5250                         flags |= IFF_RUNNING;
5251                 if (netif_carrier_ok(dev))
5252                         flags |= IFF_LOWER_UP;
5253                 if (netif_dormant(dev))
5254                         flags |= IFF_DORMANT;
5255         }
5256 
5257         return flags;
5258 }
5259 EXPORT_SYMBOL(dev_get_flags);
5260 
5261 int __dev_change_flags(struct net_device *dev, unsigned int flags)
5262 {
5263         unsigned int old_flags = dev->flags;
5264         int ret;
5265 
5266         ASSERT_RTNL();
5267 
5268         /*
5269          *      Set the flags on our device.
5270          */
5271 
5272         dev->flags = (flags & (IFF_DEBUG | IFF_NOTRAILERS | IFF_NOARP |
5273                                IFF_DYNAMIC | IFF_MULTICAST | IFF_PORTSEL |
5274                                IFF_AUTOMEDIA)) |
5275                      (dev->flags & (IFF_UP | IFF_VOLATILE | IFF_PROMISC |
5276                                     IFF_ALLMULTI));
5277 
5278         /*
5279          *      Load in the correct multicast list now the flags have changed.
5280          */
5281 
5282         if ((old_flags ^ flags) & IFF_MULTICAST)
5283                 dev_change_rx_flags(dev, IFF_MULTICAST);
5284 
5285         dev_set_rx_mode(dev);
5286 
5287         /*
5288          *      Have we downed the interface. We handle IFF_UP ourselves
5289          *      according to user attempts to set it, rather than blindly
5290          *      setting it.
5291          */
5292 
5293         ret = 0;
5294         if ((old_flags ^ flags) & IFF_UP) {     /* Bit is different  ? */
5295                 ret = ((old_flags & IFF_UP) ? __dev_close : __dev_open)(dev);
5296 
5297                 if (!ret)
5298                         dev_set_rx_mode(dev);
5299         }
5300 
5301         if ((flags ^ dev->gflags) & IFF_PROMISC) {
5302                 int inc = (flags & IFF_PROMISC) ? 1 : -1;
5303                 unsigned int old_flags = dev->flags;
5304 
5305                 dev->gflags ^= IFF_PROMISC;
5306 
5307                 if (__dev_set_promiscuity(dev, inc, false) >= 0)
5308                         if (dev->flags != old_flags)
5309                                 dev_set_rx_mode(dev);
5310         }
5311 
5312         /* NOTE: order of synchronization of IFF_PROMISC and IFF_ALLMULTI
5313            is important. Some (broken) drivers set IFF_PROMISC, when
5314            IFF_ALLMULTI is requested not asking us and not reporting.
5315          */
5316         if ((flags ^ dev->gflags) & IFF_ALLMULTI) {
5317                 int inc = (flags & IFF_ALLMULTI) ? 1 : -1;
5318 
5319                 dev->gflags ^= IFF_ALLMULTI;
5320                 __dev_set_allmulti(dev, inc, false);
5321         }
5322 
5323         return ret;
5324 }
5325 
5326 void __dev_notify_flags(struct net_device *dev, unsigned int old_flags,
5327                         unsigned int gchanges)
5328 {
5329         unsigned int changes = dev->flags ^ old_flags;
5330 
5331         if (gchanges)
5332                 rtmsg_ifinfo(RTM_NEWLINK, dev, gchanges, GFP_ATOMIC);
5333 
5334         if (changes & IFF_UP) {
5335                 if (dev->flags & IFF_UP)
5336                         call_netdevice_notifiers(NETDEV_UP, dev);
5337                 else
5338                         call_netdevice_notifiers(NETDEV_DOWN, dev);
5339         }
5340 
5341         if (dev->flags & IFF_UP &&
5342             (changes & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI | IFF_VOLATILE))) {
5343                 struct netdev_notifier_change_info change_info;
5344 
5345                 change_info.flags_changed = changes;
5346                 call_netdevice_notifiers_info(NETDEV_CHANGE, dev,
5347                                               &change_info.info);
5348         }
5349 }
5350 
5351 /**
5352  *      dev_change_flags - change device settings
5353  *      @dev: device
5354  *      @flags: device state flags
5355  *
5356  *      Change settings on device based state flags. The flags are
5357  *      in the userspace exported format.
5358  */
5359 int dev_change_flags(struct net_device *dev, unsigned int flags)
5360 {
5361         int ret;
5362         unsigned int changes, old_flags = dev->flags, old_gflags = dev->gflags;
5363 
5364         ret = __dev_change_flags(dev, flags);
5365         if (ret < 0)
5366                 return ret;
5367 
5368         changes = (old_flags ^ dev->flags) | (old_gflags ^ dev->gflags);
5369         __dev_notify_flags(dev, old_flags, changes);
5370         return ret;
5371 }
5372 EXPORT_SYMBOL(dev_change_flags);
5373 
5374 static int __dev_set_mtu(struct net_device *dev, int new_mtu)
5375 {
5376         const struct net_device_ops *ops = dev->netdev_ops;
5377 
5378         if (ops->ndo_change_mtu)
5379                 return ops->ndo_change_mtu(dev, new_mtu);
5380 
5381         dev->mtu = new_mtu;
5382         return 0;
5383 }
5384 
5385 /**
5386  *      dev_set_mtu - Change maximum transfer unit
5387  *      @dev: device
5388  *      @new_mtu: new transfer unit
5389  *
5390  *      Change the maximum transfer size of the network device.
5391  */
5392 int dev_set_mtu(struct net_device *dev, int new_mtu)
5393 {
5394         int err, orig_mtu;
5395 
5396         if (new_mtu == dev->mtu)
5397                 return 0;
5398 
5399         /*      MTU must be positive.    */
5400         if (new_mtu < 0)
5401                 return -EINVAL;
5402 
5403         if (!netif_device_present(dev))
5404                 return -ENODEV;
5405 
5406         err = call_netdevice_notifiers(NETDEV_PRECHANGEMTU, dev);
5407         err = notifier_to_errno(err);
5408         if (err)
5409                 return err;
5410 
5411         orig_mtu = dev->mtu;
5412         err = __dev_set_mtu(dev, new_mtu);
5413 
5414         if (!err) {
5415                 err = call_netdevice_notifiers(NETDEV_CHANGEMTU, dev);
5416                 err = notifier_to_errno(err);
5417                 if (err) {
5418                         /* setting mtu back and notifying everyone again,
5419                          * so that they have a chance to revert changes.
5420                          */
5421                         __dev_set_mtu(dev, orig_mtu);
5422                         call_netdevice_notifiers(NETDEV_CHANGEMTU, dev);
5423                 }
5424         }
5425         return err;
5426 }
5427 EXPORT_SYMBOL(dev_set_mtu);
5428 
5429 /**
5430  *      dev_set_group - Change group this device belongs to
5431  *      @dev: device
5432  *      @new_group: group this device should belong to
5433  */
5434 void dev_set_group(struct net_device *dev, int new_group)
5435 {
5436         dev->group = new_group;
5437 }
5438 EXPORT_SYMBOL(dev_set_group);
5439 
5440 /**
5441  *      dev_set_mac_address - Change Media Access Control Address
5442  *      @dev: device
5443  *      @sa: new address
5444  *
5445  *      Change the hardware (MAC) address of the device
5446  */
5447 int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
5448 {
5449         const struct net_device_ops *ops = dev->netdev_ops;
5450         int err;
5451 
5452         if (!ops->ndo_set_mac_address)
5453                 return -EOPNOTSUPP;
5454         if (sa->sa_family != dev->type)
5455                 return -EINVAL;
5456         if (!netif_device_present(dev))
5457                 return -ENODEV;
5458         err = ops->ndo_set_mac_address(dev, sa);
5459         if (err)
5460                 return err;
5461         dev->addr_assign_type = NET_ADDR_SET;
5462         call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
5463         add_device_randomness(dev->dev_addr, dev->addr_len);
5464         return 0;
5465 }
5466 EXPORT_SYMBOL(dev_set_mac_address);
5467 
5468 /**
5469  *      dev_change_carrier - Change device carrier
5470  *      @dev: device
5471  *      @new_carrier: new value
5472  *
5473  *      Change device carrier
5474  */
5475 int dev_change_carrier(struct net_device *dev, bool new_carrier)
5476 {
5477         const struct net_device_ops *ops = dev->netdev_ops;
5478 
5479         if (!ops->ndo_change_carrier)
5480                 return -EOPNOTSUPP;
5481         if (!netif_device_present(dev))
5482                 return -ENODEV;
5483         return ops->ndo_change_carrier(dev, new_carrier);
5484 }
5485 EXPORT_SYMBOL(dev_change_carrier);
5486 
5487 /**
5488  *      dev_get_phys_port_id - Get device physical port ID
5489  *      @dev: device
5490  *      @ppid: port ID
5491  *
5492  *      Get device physical port ID
5493  */
5494 int dev_get_phys_port_id(struct net_device *dev,
5495                          struct netdev_phys_port_id *ppid)
5496 {
5497         const struct net_device_ops *ops = dev->netdev_ops;
5498 
5499         if (!ops->ndo_get_phys_port_id)
5500                 return -EOPNOTSUPP;
5501         return ops->ndo_get_phys_port_id(dev, ppid);
5502 }
5503 EXPORT_SYMBOL(dev_get_phys_port_id);
5504 
5505 /**
5506  *      dev_new_index   -       allocate an ifindex
5507  *      @net: the applicable net namespace
5508  *
5509  *      Returns a suitable unique value for a new device interface
5510  *      number.  The caller must hold the rtnl semaphore or the
5511  *      dev_base_lock to be sure it remains unique.
5512  */
5513 static int dev_new_index(struct net *net)
5514 {
5515         int ifindex = net->ifindex;
5516         for (;;) {
5517                 if (++ifindex <= 0)
5518                         ifindex = 1;
5519                 if (!__dev_get_by_index(net, ifindex))
5520                         return net->ifindex = ifindex;
5521         }
5522 }
5523 
5524 /* Delayed registration/unregisteration */
5525 static LIST_HEAD(net_todo_list);
5526 static DECLARE_WAIT_QUEUE_HEAD(netdev_unregistering_wq);
5527 
5528 static void net_set_todo(struct net_device *dev)
5529 {
5530         list_add_tail(&dev->todo_list, &net_todo_list);
5531         dev_net(dev)->dev_unreg_count++;
5532 }
5533 
5534 static void rollback_registered_many(struct list_head *head)
5535 {
5536         struct net_device *dev, *tmp;
5537         LIST_HEAD(close_head);
5538 
5539         BUG_ON(dev_boot_phase);
5540         ASSERT_RTNL();
5541 
5542         list_for_each_entry_safe(dev, tmp, head, unreg_list) {
5543                 /* Some devices call without registering
5544                  * for initialization unwind. Remove those
5545                  * devices and proceed with the remaining.
5546                  */
5547                 if (dev->reg_state == NETREG_UNINITIALIZED) {
5548                         pr_debug("unregister_netdevice: device %s/%p never was registered\n",
5549                                  dev->name, dev);
5550 
5551                         WARN_ON(1);
5552                         list_del(&dev->unreg_list);
5553                         continue;
5554                 }
5555                 dev->dismantle = true;
5556                 BUG_ON(dev->reg_state != NETREG_REGISTERED);
5557         }
5558 
5559         /* If device is running, close it first. */
5560         list_for_each_entry(dev, head, unreg_list)
5561                 list_add_tail(&dev->close_list, &close_head);
5562         dev_close_many(&close_head);
5563 
5564         list_for_each_entry(dev, head, unreg_list) {
5565                 /* And unlink it from device chain. */
5566                 unlist_netdevice(dev);
5567 
5568                 dev->reg_state = NETREG_UNREGISTERING;
5569         }
5570 
5571         synchronize_net();
5572 
5573         list_for_each_entry(dev, head, unreg_list) {
5574                 /* Shutdown queueing discipline. */
5575                 dev_shutdown(dev);
5576 
5577 
5578                 /* Notify protocols, that we are about to destroy
5579                    this device. They should clean all the things.
5580                 */
5581                 call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
5582 
5583                 if (!dev->rtnl_link_ops ||
5584                     dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
5585                         rtmsg_ifinfo(RTM_DELLINK, dev, ~0U, GFP_KERNEL);
5586 
5587                 /*
5588                  *      Flush the unicast and multicast chains
5589                  */
5590                 dev_uc_flush(dev);
5591                 dev_mc_flush(dev);
5592 
5593                 if (dev->netdev_ops->ndo_uninit)
5594                         dev->netdev_ops->ndo_uninit(dev);
5595 
5596                 /* Notifier chain MUST detach us all upper devices. */
5597                 WARN_ON(netdev_has_any_upper_dev(dev));
5598 
5599                 /* Remove entries from kobject tree */
5600                 netdev_unregister_kobject(dev);
5601 #ifdef CONFIG_XPS
5602                 /* Remove XPS queueing entries */
5603                 netif_reset_xps_queues_gt(dev, 0);
5604 #endif
5605         }
5606 
5607         synchronize_net();
5608 
5609         list_for_each_entry(dev, head, unreg_list)
5610                 dev_put(dev);
5611 }
5612 
5613 static void rollback_registered(struct net_device *dev)
5614 {
5615         LIST_HEAD(single);
5616 
5617         list_add(&dev->unreg_list, &single);
5618         rollback_registered_many(&single);
5619         list_del(&single);
5620 }
5621 
5622 static netdev_features_t netdev_fix_features(struct net_device *dev,
5623         netdev_features_t features)
5624 {
5625         /* Fix illegal checksum combinations */
5626         if ((features & NETIF_F_HW_CSUM) &&
5627             (features & (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
5628                 netdev_warn(dev, "mixed HW and IP checksum settings.\n");
5629                 features &= ~(NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM);
5630         }
5631 
5632         /* TSO requires that SG is present as well. */
5633         if ((features & NETIF_F_ALL_TSO) && !(features & NETIF_F_SG)) {
5634                 netdev_dbg(dev, "Dropping TSO features since no SG feature.\n");
5635                 features &= ~NETIF_F_ALL_TSO;
5636         }
5637 
5638         if ((features & NETIF_F_TSO) && !(features & NETIF_F_HW_CSUM) &&
5639                                         !(features & NETIF_F_IP_CSUM)) {
5640                 netdev_dbg(dev, "Dropping TSO features since no CSUM feature.\n");
5641                 features &= ~NETIF_F_TSO;
5642                 features &= ~NETIF_F_TSO_ECN;
5643         }
5644 
5645         if ((features & NETIF_F_TSO6) && !(features & NETIF_F_HW_CSUM) &&
5646                                          !(features & NETIF_F_IPV6_CSUM)) {
5647                 netdev_dbg(dev, "Dropping TSO6 features since no CSUM feature.\n");
5648                 features &= ~NETIF_F_TSO6;
5649         }
5650 
5651         /* TSO ECN requires that TSO is present as well. */
5652         if ((features & NETIF_F_ALL_TSO) == NETIF_F_TSO_ECN)
5653                 features &= ~NETIF_F_TSO_ECN;
5654 
5655         /* Software GSO depends on SG. */
5656         if ((features & NETIF_F_GSO) && !(features & NETIF_F_SG)) {
5657                 netdev_dbg(dev, "Dropping NETIF_F_GSO since no SG feature.\n");
5658                 features &= ~NETIF_F_GSO;
5659         }
5660 
5661         /* UFO needs SG and checksumming */
5662         if (features & NETIF_F_UFO) {
5663                 /* maybe split UFO into V4 and V6? */
5664                 if (!((features & NETIF_F_GEN_CSUM) ||
5665                     (features & (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))
5666                             == (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
5667                         netdev_dbg(dev,
5668                                 "Dropping NETIF_F_UFO since no checksum offload features.\n");
5669                         features &= ~NETIF_F_UFO;
5670                 }
5671 
5672                 if (!(features & NETIF_F_SG)) {
5673                         netdev_dbg(dev,
5674                                 "Dropping NETIF_F_UFO since no NETIF_F_SG feature.\n");
5675                         features &= ~NETIF_F_UFO;
5676                 }
5677         }
5678 
5679         return features;
5680 }
5681 
5682 int __netdev_update_features(struct net_device *dev)
5683 {
5684         netdev_features_t features;
5685         int err = 0;
5686 
5687         ASSERT_RTNL();
5688 
5689         features = netdev_get_wanted_features(dev);
5690 
5691         if (dev->netdev_ops->ndo_fix_features)
5692                 features = dev->netdev_ops->ndo_fix_features(dev, features);
5693 
5694         /* driver might be less strict about feature dependencies */
5695         features = netdev_fix_features(dev, features);
5696 
5697         if (dev->features == features)
5698                 return 0;
5699 
5700         netdev_dbg(dev, "Features changed: %pNF -> %pNF\n",
5701                 &dev->features, &features);
5702 
5703         if (dev->netdev_ops->ndo_set_features)
5704                 err = dev->netdev_ops->ndo_set_features(dev, features);
5705 
5706         if (unlikely(err < 0)) {
5707                 netdev_err(dev,
5708                         "set_features() failed (%d); wanted %pNF, left %pNF\n",
5709                         err, &features, &dev->features);
5710                 return -1;
5711         }
5712 
5713         if (!err)
5714                 dev->features = features;
5715 
5716         return 1;
5717 }
5718 
5719 /**
5720  *      netdev_update_features - recalculate device features
5721  *      @dev: the device to check
5722  *
5723  *      Recalculate dev->features set and send notifications if it
5724  *      has changed. Should be called after driver or hardware dependent
5725  *      conditions might have changed that influence the features.
5726  */
5727 void netdev_update_features(struct net_device *dev)
5728 {
5729         if (__netdev_update_features(dev))
5730                 netdev_features_change(dev);
5731 }
5732 EXPORT_SYMBOL(netdev_update_features);
5733 
5734 /**
5735  *      netdev_change_features - recalculate device features
5736  *      @dev: the device to check
5737  *
5738  *      Recalculate dev->features set and send notifications even
5739  *      if they have not changed. Should be called instead of
5740  *      netdev_update_features() if also dev->vlan_features might
5741  *      have changed to allow the changes to be propagated to stacked
5742  *      VLAN devices.
5743  */
5744 void netdev_change_features(struct net_device *dev)
5745 {
5746         __netdev_update_features(dev);
5747         netdev_features_change(dev);
5748 }
5749 EXPORT_SYMBOL(netdev_change_features);
5750 
5751 /**
5752  *      netif_stacked_transfer_operstate -      transfer operstate
5753  *      @rootdev: the root or lower level device to transfer state from
5754  *      @dev: the device to transfer operstate to
5755  *
5756  *      Transfer operational state from root to device. This is normally
5757  *      called when a stacking relationship exists between the root
5758  *      device and the device(a leaf device).
5759  */
5760 void netif_stacked_transfer_operstate(const struct net_device *rootdev,
5761                                         struct net_device *dev)
5762 {
5763         if (rootdev->operstate == IF_OPER_DORMANT)
5764                 netif_dormant_on(dev);
5765         else
5766                 netif_dormant_off(dev);
5767 
5768         if (netif_carrier_ok(rootdev)) {
5769                 if (!netif_carrier_ok(dev))
5770                         netif_carrier_on(dev);
5771         } else {
5772                 if (netif_carrier_ok(dev))
5773                         netif_carrier_off(dev);
5774         }
5775 }
5776 EXPORT_SYMBOL(netif_stacked_transfer_operstate);
5777 
5778 #ifdef CONFIG_SYSFS
5779 static int netif_alloc_rx_queues(struct net_device *dev)
5780 {
5781         unsigned int i, count = dev->num_rx_queues;
5782         struct netdev_rx_queue *rx;
5783 
5784         BUG_ON(count < 1);
5785 
5786         rx = kcalloc(count, sizeof(struct netdev_rx_queue), GFP_KERNEL);
5787         if (!rx)
5788                 return -ENOMEM;
5789 
5790         dev->_rx = rx;
5791 
5792         for (i = 0; i < count; i++)
5793                 rx[i].dev = dev;
5794         return 0;
5795 }
5796 #endif
5797 
5798 static void netdev_init_one_queue(struct net_device *dev,
5799                                   struct netdev_queue *queue, void *_unused)
5800 {
5801         /* Initialize queue lock */
5802         spin_lock_init(&queue->_xmit_lock);
5803         netdev_set_xmit_lockdep_class(&queue->_xmit_lock, dev->type);
5804         queue->xmit_lock_owner = -1;
5805         netdev_queue_numa_node_write(queue, NUMA_NO_NODE);
5806         queue->dev = dev;
5807 #ifdef CONFIG_BQL
5808         dql_init(&queue->dql, HZ);
5809 #endif
5810 }
5811 
5812 static void netif_free_tx_queues(struct net_device *dev)
5813 {
5814         if (is_vmalloc_addr(dev->_tx))
5815                 vfree(dev->_tx);
5816         else
5817                 kfree(dev->_tx);
5818 }
5819 
5820 static int netif_alloc_netdev_queues(struct net_device *dev)
5821 {
5822         unsigned int count = dev->num_tx_queues;
5823         struct netdev_queue *tx;
5824         size_t sz = count * sizeof(*tx);
5825 
5826         BUG_ON(count < 1 || count > 0xffff);
5827 
5828         tx = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
5829         if (!tx) {
5830                 tx = vzalloc(sz);
5831                 if (!tx)
5832                         return -ENOMEM;
5833         }
5834         dev->_tx = tx;
5835 
5836         netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
5837         spin_lock_init(&dev->tx_global_lock);
5838 
5839         return 0;
5840 }
5841 
5842 /**
5843  *      register_netdevice      - register a network device
5844  *      @dev: device to register
5845  *
5846  *      Take a completed network device structure and add it to the kernel
5847  *      interfaces. A %NETDEV_REGISTER message is sent to the netdev notifier
5848  *      chain. 0 is returned on success. A negative errno code is returned
5849  *      on a failure to set up the device, or if the name is a duplicate.
5850  *
5851  *      Callers must hold the rtnl semaphore. You may want
5852  *      register_netdev() instead of this.
5853  *
5854  *      BUGS:
5855  *      The locking appears insufficient to guarantee two parallel registers
5856  *      will not get the same name.
5857  */
5858 
5859 int register_netdevice(struct net_device *dev)
5860 {
5861         int ret;
5862         struct net *net = dev_net(dev);
5863 
5864         BUG_ON(dev_boot_phase);
5865         ASSERT_RTNL();
5866 
5867         might_sleep();
5868 
5869         /* When net_device's are persistent, this will be fatal. */
5870         BUG_ON(dev->reg_state != NETREG_UNINITIALIZED);
5871         BUG_ON(!net);
5872 
5873         spin_lock_init(&dev->addr_list_lock);
5874         netdev_set_addr_lockdep_class(dev);
5875 
5876         dev->iflink = -1;
5877 
5878         ret = dev_get_valid_name(net, dev, dev->name);
5879         if (ret < 0)
5880                 goto out;
5881 
5882         /* Init, if this function is available */
5883         if (dev->netdev_ops->ndo_init) {
5884                 ret = dev->netdev_ops->ndo_init(dev);
5885                 if (ret) {
5886                         if (ret > 0)
5887                                 ret = -EIO;
5888                         goto out;
5889                 }
5890         }
5891 
5892         if (((dev->hw_features | dev->features) &
5893              NETIF_F_HW_VLAN_CTAG_FILTER) &&
5894             (!dev->netdev_ops->ndo_vlan_rx_add_vid ||
5895              !dev->netdev_ops->ndo_vlan_rx_kill_vid)) {
5896                 netdev_WARN(dev, "Buggy VLAN acceleration in driver!\n");
5897                 ret = -EINVAL;
5898                 goto err_uninit;
5899         }
5900 
5901         ret = -EBUSY;
5902         if (!dev->ifindex)
5903                 dev->ifindex = dev_new_index(net);
5904         else if (__dev_get_by_index(net, dev->ifindex))
5905                 goto err_uninit;
5906 
5907         if (dev->iflink == -1)
5908                 dev->iflink = dev->ifindex;
5909 
5910         /* Transfer changeable features to wanted_features and enable
5911          * software offloads (GSO and GRO).
5912          */
5913         dev->hw_features |= NETIF_F_SOFT_FEATURES;
5914         dev->features |= NETIF_F_SOFT_FEATURES;
5915         dev->wanted_features = dev->features & dev->hw_features;
5916 
5917         if (!(dev->flags & IFF_LOOPBACK)) {
5918                 dev->hw_features |= NETIF_F_NOCACHE_COPY;
5919         }
5920 
5921         /* Make NETIF_F_HIGHDMA inheritable to VLAN devices.
5922          */
5923         dev->vlan_features |= NETIF_F_HIGHDMA;
5924 
5925         /* Make NETIF_F_SG inheritable to tunnel devices.
5926          */
5927         dev->hw_enc_features |= NETIF_F_SG;
5928 
5929         /* Make NETIF_F_SG inheritable to MPLS.
5930          */
5931         dev->mpls_features |= NETIF_F_SG;
5932 
5933         ret = call_netdevice_notifiers(NETDEV_POST_INIT, dev);
5934         ret = notifier_to_errno(ret);
5935         if (ret)
5936                 goto err_uninit;
5937 
5938         ret = netdev_register_kobject(dev);
5939         if (ret)
5940                 goto err_uninit;
5941         dev->reg_state = NETREG_REGISTERED;
5942 
5943         __netdev_update_features(dev);
5944 
5945         /*
5946          *      Default initial state at registry is that the
5947          *      device is present.
5948          */
5949 
5950         set_bit(__LINK_STATE_PRESENT, &dev->state);
5951 
5952         linkwatch_init_dev(dev);
5953 
5954         dev_init_scheduler(dev);
5955         dev_hold(dev);
5956         list_netdevice(dev);
5957         add_device_randomness(dev->dev_addr, dev->addr_len);
5958 
5959         /* If the device has permanent device address, driver should
5960          * set dev_addr and also addr_assign_type should be set to
5961          * NET_ADDR_PERM (default value).
5962          */
5963         if (dev->addr_assign_type == NET_ADDR_PERM)
5964                 memcpy(dev->perm_addr, dev->dev_addr, dev->addr_len);
5965 
5966         /* Notify protocols, that a new device appeared. */
5967         ret = call_netdevice_notifiers(NETDEV_REGISTER, dev);
5968         ret = notifier_to_errno(ret);
5969         if (ret) {
5970                 rollback_registered(dev);
5971                 dev->reg_state = NETREG_UNREGISTERED;
5972         }
5973         /*
5974          *      Prevent userspace races by waiting until the network
5975          *      device is fully setup before sending notifications.
5976          */
5977         if (!dev->rtnl_link_ops ||
5978             dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
5979                 rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U, GFP_KERNEL);
5980 
5981 out:
5982         return ret;
5983 
5984 err_uninit:
5985         if (dev->netdev_ops->ndo_uninit)
5986                 dev->netdev_ops->ndo_uninit(dev);
5987         goto out;
5988 }
5989 EXPORT_SYMBOL(register_netdevice);
5990 
5991 /**
5992  *      init_dummy_netdev       - init a dummy network device for NAPI
5993  *      @dev: device to init
5994  *
5995  *      This takes a network device structure and initialize the minimum
5996  *      amount of fields so it can be used to schedule NAPI polls without
5997  *      registering a full blown interface. This is to be used by drivers
5998  *      that need to tie several hardware interfaces to a single NAPI
5999  *      poll scheduler due to HW limitations.
6000  */
6001 int init_dummy_netdev(struct net_device *dev)
6002 {
6003         /* Clear everything. Note we don't initialize spinlocks
6004          * are they aren't supposed to be taken by any of the
6005          * NAPI code and this dummy netdev is supposed to be
6006          * only ever used for NAPI polls
6007          */
6008         memset(dev, 0, sizeof(struct net_device));
6009 
6010         /* make sure we BUG if trying to hit standard
6011          * register/unregister code path
6012          */
6013         dev->reg_state = NETREG_DUMMY;
6014 
6015         /* NAPI wants this */
6016         INIT_LIST_HEAD(&dev->napi_list);
6017 
6018         /* a dummy interface is started by default */
6019         set_bit(__LINK_STATE_PRESENT, &dev->state);
6020         set_bit(__LINK_STATE_START, &dev->state);
6021 
6022         /* Note : We dont allocate pcpu_refcnt for dummy devices,
6023          * because users of this 'device' dont need to change
6024          * its refcount.
6025          */
6026 
6027         return 0;
6028 }
6029 EXPORT_SYMBOL_GPL(init_dummy_netdev);
6030 
6031 
6032 /**
6033  *      register_netdev - register a network device
6034  *      @dev: device to register
6035  *
6036  *      Take a completed network device structure and add it to the kernel
6037  *      interfaces. A %NETDEV_REGISTER message is sent to the netdev notifier
6038  *      chain. 0 is returned on success. A negative errno code is returned
6039  *      on a failure to set up the device, or if the name is a duplicate.
6040  *
6041  *      This is a wrapper around register_netdevice that takes the rtnl semaphore
6042  *      and expands the device name if you passed a format string to
6043  *      alloc_netdev.
6044  */
6045 int register_netdev(struct net_device *dev)
6046 {
6047         int err;
6048 
6049         rtnl_lock();
6050         err = register_netdevice(dev);
6051         rtnl_unlock();
6052         return err;
6053 }
6054 EXPORT_SYMBOL(register_netdev);
6055 
6056 int netdev_refcnt_read(const struct net_device *dev)
6057 {
6058         int i, refcnt = 0;
6059 
6060         for_each_possible_cpu(i)
6061                 refcnt += *per_cpu_ptr(dev->pcpu_refcnt, i);
6062         return refcnt;
6063 }
6064 EXPORT_SYMBOL(netdev_refcnt_read);
6065 
6066 /**
6067  * netdev_wait_allrefs - wait until all references are gone.
6068  * @dev: target net_device
6069  *
6070  * This is called when unregistering network devices.
6071  *
6072  * Any protocol or device that holds a reference should register
6073  * for netdevice notification, and cleanup and put back the
6074  * reference if they receive an UNREGISTER event.
6075  * We can get stuck here if buggy protocols don't correctly
6076  * call dev_put.
6077  */
6078 static void netdev_wait_allrefs(struct net_device *dev)
6079 {
6080         unsigned long rebroadcast_time, warning_time;
6081         int refcnt;
6082 
6083         linkwatch_forget_dev(dev);
6084 
6085         rebroadcast_time = warning_time = jiffies;
6086         refcnt = netdev_refcnt_read(dev);
6087 
6088         while (refcnt != 0) {
6089                 if (time_after(jiffies, rebroadcast_time + 1 * HZ)) {
6090                         rtnl_lock();
6091 
6092                         /* Rebroadcast unregister notification */
6093                         call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
6094 
6095                         __rtnl_unlock();
6096                         rcu_barrier();
6097                         rtnl_lock();
6098 
6099                         call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev);
6100                         if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
6101                                      &dev->state)) {
6102                                 /* We must not have linkwatch events
6103                                  * pending on unregister. If this
6104                                  * happens, we simply run the queue
6105                                  * unscheduled, resulting in a noop
6106                                  * for this device.
6107                                  */
6108                                 linkwatch_run_queue();
6109                         }
6110 
6111                         __rtnl_unlock();
6112 
6113                         rebroadcast_time = jiffies;
6114                 }
6115 
6116                 msleep(250);
6117 
6118                 refcnt = netdev_refcnt_read(dev);
6119 
6120                 if (time_after(jiffies, warning_time + 10 * HZ)) {
6121                         pr_emerg("unregister_netdevice: waiting for %s to become free. Usage count = %d\n",
6122                                  dev->name, refcnt);
6123                         warning_time = jiffies;
6124                 }
6125         }
6126 }
6127 
6128 /* The sequence is:
6129  *
6130  *      rtnl_lock();
6131  *      ...
6132  *      register_netdevice(x1);
6133  *      register_netdevice(x2);
6134  *      ...
6135  *      unregister_netdevice(y1);
6136  *      unregister_netdevice(y2);
6137  *      ...
6138  *      rtnl_unlock();
6139  *      free_netdev(y1);
6140  *      free_netdev(y2);
6141  *
6142  * We are invoked by rtnl_unlock().
6143  * This allows us to deal with problems:
6144  * 1) We can delete sysfs objects which invoke hotplug
6145  *    without deadlocking with linkwatch via keventd.
6146  * 2) Since we run with the RTNL semaphore not held, we can sleep
6147  *    safely in order to wait for the netdev refcnt to drop to zero.
6148  *
6149  * We must not return until all unregister events added during
6150  * the interval the lock was held have been completed.
6151  */
6152 void netdev_run_todo(void)
6153 {
6154         struct list_head list;
6155 
6156         /* Snapshot list, allow later requests */
6157         list_replace_init(&net_todo_list, &list);
6158 
6159         __rtnl_unlock();
6160 
6161 
6162         /* Wait for rcu callbacks to finish before next phase */
6163         if (!list_empty(&list))
6164                 rcu_barrier();
6165 
6166         while (!list_empty(&list)) {
6167                 struct net_device *dev
6168                         = list_first_entry(&list, struct net_device, todo_list);
6169                 list_del(&dev->todo_list);
6170 
6171                 rtnl_lock();
6172                 call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev);
6173                 __rtnl_unlock();
6174 
6175                 if (unlikely(dev->reg_state != NETREG_UNREGISTERING)) {
6176                         pr_err("network todo '%s' but state %d\n",
6177                                dev->name, dev->reg_state);
6178                         dump_stack();
6179                         continue;
6180                 }
6181 
6182                 dev->reg_state = NETREG_UNREGISTERED;
6183 
6184                 on_each_cpu(flush_backlog, dev, 1);
6185 
6186                 netdev_wait_allrefs(dev);
6187 
6188                 /* paranoia */
6189                 BUG_ON(netdev_refcnt_read(dev));
6190                 WARN_ON(rcu_access_pointer(dev->ip_ptr));
6191                 WARN_ON(rcu_access_pointer(dev->ip6_ptr));
6192                 WARN_ON(dev->dn_ptr);
6193 
6194                 if (dev->destructor)
6195                         dev->destructor(dev);
6196 
6197                 /* Report a network device has been unregistered */
6198                 rtnl_lock();
6199                 dev_net(dev)->dev_unreg_count--;
6200                 __rtnl_unlock();
6201                 wake_up(&netdev_unregistering_wq);
6202 
6203                 /* Free network device */
6204                 kobject_put(&dev->dev.kobj);
6205         }
6206 }
6207 
6208 /* Convert net_device_stats to rtnl_link_stats64.  They have the same
6209  * fields in the same order, with only the type differing.
6210  */
6211 void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
6212                              const struct net_device_stats *netdev_stats)
6213 {
6214 #if BITS_PER_LONG == 64
6215         BUILD_BUG_ON(sizeof(*stats64) != sizeof(*netdev_stats));
6216         memcpy(stats64, netdev_stats, sizeof(*stats64));
6217 #else
6218         size_t i, n = sizeof(*stats64) / sizeof(u64);
6219         const unsigned long *src = (const unsigned long *)netdev_stats;
6220         u64 *dst = (u64 *)stats64;
6221 
6222         BUILD_BUG_ON(sizeof(*netdev_stats) / sizeof(unsigned long) !=
6223                      sizeof(*stats64) / sizeof(u64));
6224         for (i = 0; i < n; i++)
6225                 dst[i] = src[i];
6226 #endif
6227 }
6228 EXPORT_SYMBOL(netdev_stats_to_stats64);
6229 
6230 /**
6231  *      dev_get_stats   - get network device statistics
6232  *      @dev: device to get statistics from
6233  *      @storage: place to store stats
6234  *
6235  *      Get network statistics from device. Return @storage.
6236  *      The device driver may provide its own method by setting
6237  *      dev->netdev_ops->get_stats64 or dev->netdev_ops->get_stats;
6238  *      otherwise the internal statistics structure is used.
6239  */
6240 struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
6241                                         struct rtnl_link_stats64 *storage)
6242 {
6243         const struct net_device_ops *ops = dev->netdev_ops;
6244 
6245         if (ops->ndo_get_stats64) {
6246                 memset(storage, 0, sizeof(*storage));
6247                 ops->ndo_get_stats64(dev, storage);
6248         } else if (ops->ndo_get_stats) {
6249                 netdev_stats_to_stats64(storage, ops->ndo_get_stats(dev));
6250         } else {
6251                 netdev_stats_to_stats64(storage, &dev->stats);
6252         }
6253         storage->rx_dropped += atomic_long_read(&dev->rx_dropped);
6254         return storage;
6255 }
6256 EXPORT_SYMBOL(dev_get_stats);
6257 
6258 struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
6259 {
6260         struct netdev_queue *queue = dev_ingress_queue(dev);
6261 
6262 #ifdef CONFIG_NET_CLS_ACT
6263         if (queue)
6264                 return queue;
6265         queue = kzalloc(sizeof(*queue), GFP_KERNEL);
6266         if (!queue)
6267                 return NULL;
6268         netdev_init_one_queue(dev, queue, NULL);
6269         queue->qdisc = &noop_qdisc;
6270         queue->qdisc_sleeping = &noop_qdisc;
6271         rcu_assign_pointer(dev->ingress_queue, queue);
6272 #endif
6273         return queue;
6274 }
6275 
6276 static const struct ethtool_ops default_ethtool_ops;
6277 
6278 void netdev_set_default_ethtool_ops(struct net_device *dev,
6279                                     const struct ethtool_ops *ops)
6280 {
6281         if (dev->ethtool_ops == &default_ethtool_ops)
6282                 dev->ethtool_ops = ops;
6283 }
6284 EXPORT_SYMBOL_GPL(netdev_set_default_ethtool_ops);
6285 
6286 void netdev_freemem(struct net_device *dev)
6287 {
6288         char *addr = (char *)dev - dev->padded;
6289 
6290         if (is_vmalloc_addr(addr))
6291                 vfree(addr);
6292         else
6293                 kfree(addr);
6294 }
6295 
6296 /**
6297  *      alloc_netdev_mqs - allocate network device
6298  *      @sizeof_priv:   size of private data to allocate space for
6299  *      @name:          device name format string
6300  *      @setup:         callback to initialize device
6301  *      @txqs:          the number of TX subqueues to allocate
6302  *      @rxqs:          the number of RX subqueues to allocate
6303  *
6304  *      Allocates a struct net_device with private data area for driver use
6305  *      and performs basic initialization.  Also allocates subqueue structs
6306  *      for each queue on the device.
6307  */
6308 struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
6309                 void (*setup)(struct net_device *),
6310                 unsigned int txqs, unsigned int rxqs)
6311 {
6312         struct net_device *dev;
6313         size_t alloc_size;
6314         struct net_device *p;
6315 
6316         BUG_ON(strlen(name) >= sizeof(dev->name));
6317 
6318         if (txqs < 1) {
6319                 pr_err("alloc_netdev: Unable to allocate device with zero queues\n");
6320                 return NULL;
6321         }
6322 
6323 #ifdef CONFIG_SYSFS
6324         if (rxqs < 1) {
6325                 pr_err("alloc_netdev: Unable to allocate device with zero RX queues\n");
6326                 return NULL;
6327         }
6328 #endif
6329 
6330         alloc_size = sizeof(struct net_device);
6331         if (sizeof_priv) {
6332                 /* ensure 32-byte alignment of private area */
6333                 alloc_size = ALIGN(alloc_size, NETDEV_ALIGN);
6334                 alloc_size += sizeof_priv;
6335         }
6336         /* ensure 32-byte alignment of whole construct */
6337         alloc_size += NETDEV_ALIGN - 1;
6338 
6339         p = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
6340         if (!p)
6341                 p = vzalloc(alloc_size);
6342         if (!p)
6343                 return NULL;
6344 
6345         dev = PTR_ALIGN(p, NETDEV_ALIGN);
6346         dev->padded = (char *)dev - (char *)p;
6347 
6348         dev->pcpu_refcnt = alloc_percpu(int);
6349         if (!dev->pcpu_refcnt)
6350                 goto free_dev;
6351 
6352         if (dev_addr_init(dev))
6353                 goto free_pcpu;
6354 
6355         dev_mc_init(dev);
6356         dev_uc_init(dev);
6357 
6358         dev_net_set(dev, &init_net);
6359 
6360         dev->gso_max_size = GSO_MAX_SIZE;
6361         dev->gso_max_segs = GSO_MAX_SEGS;
6362 
6363         INIT_LIST_HEAD(&dev->napi_list);
6364         INIT_LIST_HEAD(&dev->unreg_list);
6365         INIT_LIST_HEAD(&dev->close_list);
6366         INIT_LIST_HEAD(&dev->link_watch_list);
6367         INIT_LIST_HEAD(&dev->adj_list.upper);
6368         INIT_LIST_HEAD(&dev->adj_list.lower);
6369         INIT_LIST_HEAD(&dev->all_adj_list.upper);
6370         INIT_LIST_HEAD(&dev->all_adj_list.lower);
6371         dev->priv_flags = IFF_XMIT_DST_RELEASE;
6372         setup(dev);
6373 
6374         dev->num_tx_queues = txqs;
6375         dev->real_num_tx_queues = txqs;
6376         if (netif_alloc_netdev_queues(dev))
6377                 goto free_all;
6378 
6379 #ifdef CONFIG_SYSFS
6380         dev->num_rx_queues = rxqs;
6381         dev->real_num_rx_queues = rxqs;
6382         if (netif_alloc_rx_queues(dev))
6383                 goto free_all;
6384 #endif
6385 
6386         strcpy(dev->name, name);
6387         dev->group = INIT_NETDEV_GROUP;
6388         if (!dev->ethtool_ops)
6389                 dev->ethtool_ops = &default_ethtool_ops;
6390         return dev;
6391 
6392 free_all:
6393         free_netdev(dev);
6394         return NULL;
6395 
6396 free_pcpu:
6397         free_percpu(dev->pcpu_refcnt);
6398         netif_free_tx_queues(dev);
6399 #ifdef CONFIG_SYSFS
6400         kfree(dev->_rx);
6401 #endif
6402 
6403 free_dev:
6404         netdev_freemem(dev);
6405         return NULL;
6406 }
6407 EXPORT_SYMBOL(alloc_netdev_mqs);
6408 
6409 /**
6410  *      free_netdev - free network device
6411  *      @dev: device
6412  *
6413  *      This function does the last stage of destroying an allocated device
6414  *      interface. The reference to the device object is released.
6415  *      If this is the last reference then it will be freed.
6416  */
6417 void free_netdev(struct net_device *dev)
6418 {
6419         struct napi_struct *p, *n;
6420 
6421         release_net(dev_net(dev));
6422 
6423         netif_free_tx_queues(dev);
6424 #ifdef CONFIG_SYSFS
6425         kfree(dev->_rx);
6426 #endif
6427 
6428         kfree(rcu_dereference_protected(dev->ingress_queue, 1));
6429 
6430         /* Flush device addresses */
6431         dev_addr_flush(dev);
6432 
6433         list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
6434                 netif_napi_del(p);
6435 
6436         free_percpu(dev->pcpu_refcnt);
6437         dev->pcpu_refcnt = NULL;
6438 
6439         /*  Compatibility with error handling in drivers */
6440         if (dev->reg_state == NETREG_UNINITIALIZED) {
6441                 netdev_freemem(dev);
6442                 return;
6443         }
6444 
6445         BUG_ON(dev->reg_state != NETREG_UNREGISTERED);
6446         dev->reg_state = NETREG_RELEASED;
6447 
6448         /* will free via device release */
6449         put_device(&dev->dev);
6450 }
6451 EXPORT_SYMBOL(free_netdev);
6452 
6453 /**
6454  *      synchronize_net -  Synchronize with packet receive processing
6455  *
6456  *      Wait for packets currently being received to be done.
6457  *      Does not block later packets from starting.
6458  */
6459 void synchronize_net(void)
6460 {
6461         might_sleep();
6462         if (rtnl_is_locked())
6463                 synchronize_rcu_expedited();
6464         else
6465                 synchronize_rcu();
6466 }
6467 EXPORT_SYMBOL(synchronize_net);
6468 
6469 /**
6470  *      unregister_netdevice_queue - remove device from the kernel
6471  *      @dev: device
6472  *      @head: list
6473  *
6474  *      This function shuts down a device interface and removes it
6475  *      from the kernel tables.
6476  *      If head not NULL, device is queued to be unregistered later.
6477  *
6478  *      Callers must hold the rtnl semaphore.  You may want
6479  *      unregister_netdev() instead of this.
6480  */
6481 
6482 void unregister_netdevice_queue(struct net_device *dev, struct list_head *head)
6483 {
6484         ASSERT_RTNL();
6485 
6486         if (head) {
6487                 list_move_tail(&dev->unreg_list, head);
6488         } else {
6489                 rollback_registered(dev);
6490                 /* Finish processing unregister after unlock */
6491                 net_set_todo(dev);
6492         }
6493 }
6494 EXPORT_SYMBOL(unregister_netdevice_queue);
6495 
6496 /**
6497  *      unregister_netdevice_many - unregister many devices
6498  *      @head: list of devices
6499  */
6500 void unregister_netdevice_many(struct list_head *head)
6501 {
6502         struct net_device *dev;
6503 
6504         if (!list_empty(head)) {
6505                 rollback_registered_many(head);
6506                 list_for_each_entry(dev, head, unreg_list)
6507                         net_set_todo(dev);
6508         }
6509 }
6510 EXPORT_SYMBOL(unregister_netdevice_many);
6511 
6512 /**
6513  *      unregister_netdev - remove device from the kernel
6514  *      @dev: device
6515  *
6516  *      This function shuts down a device interface and removes it
6517  *      from the kernel tables.
6518  *
6519  *      This is just a wrapper for unregister_netdevice that takes
6520  *      the rtnl semaphore.  In general you want to use this and not
6521  *      unregister_netdevice.
6522  */
6523 void unregister_netdev(struct net_device *dev)
6524 {
6525         rtnl_lock();
6526         unregister_netdevice(dev);
6527         rtnl_unlock();
6528 }
6529 EXPORT_SYMBOL(unregister_netdev);
6530 
6531 /**
6532  *      dev_change_net_namespace - move device to different nethost namespace
6533  *      @dev: device
6534  *      @net: network namespace
6535  *      @pat: If not NULL name pattern to try if the current device name
6536  *            is already taken in the destination network namespace.
6537  *
6538  *      This function shuts down a device interface and moves it
6539  *      to a new network namespace. On success 0 is returned, on
6540  *      a failure a netagive errno code is returned.
6541  *
6542  *      Callers must hold the rtnl semaphore.
6543  */
6544 
6545 int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat)
6546 {
6547         int err;
6548 
6549         ASSERT_RTNL();
6550 
6551         /* Don't allow namespace local devices to be moved. */
6552         err = -EINVAL;
6553         if (dev->features & NETIF_F_NETNS_LOCAL)
6554                 goto out;
6555 
6556         /* Ensure the device has been registrered */
6557         if (dev->reg_state != NETREG_REGISTERED)
6558                 goto out;
6559 
6560         /* Get out if there is nothing todo */
6561         err = 0;
6562         if (net_eq(dev_net(dev), net))
6563                 goto out;
6564 
6565         /* Pick the destination device name, and ensure
6566          * we can use it in the destination network namespace.
6567          */
6568         err = -EEXIST;
6569         if (__dev_get_by_name(net, dev->name)) {
6570                 /* We get here if we can't use the current device name */
6571                 if (!pat)
6572                         goto out;
6573                 if (dev_get_valid_name(net, dev, pat) < 0)
6574                         goto out;
6575         }
6576 
6577         /*
6578          * And now a mini version of register_netdevice unregister_netdevice.
6579          */
6580 
6581         /* If device is running close it first. */
6582         dev_close(dev);
6583 
6584         /* And unlink it from device chain */
6585         err = -ENODEV;
6586         unlist_netdevice(dev);
6587 
6588         synchronize_net();
6589 
6590         /* Shutdown queueing discipline. */
6591         dev_shutdown(dev);
6592 
6593         /* Notify protocols, that we are about to destroy
6594            this device. They should clean all the things.
6595 
6596            Note that dev->reg_state stays at NETREG_REGISTERED.
6597            This is wanted because this way 8021q and macvlan know
6598            the device is just moving and can keep their slaves up.
6599         */
6600         call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
6601         rcu_barrier();
6602         call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev);
6603         rtmsg_ifinfo(RTM_DELLINK, dev, ~0U, GFP_KERNEL);
6604 
6605         /*
6606          *      Flush the unicast and multicast chains
6607          */
6608         dev_uc_flush(dev);
6609         dev_mc_flush(dev);
6610 
6611         /* Send a netdev-removed uevent to the old namespace */
6612         kobject_uevent(&dev->dev.kobj, KOBJ_REMOVE);
6613 
6614         /* Actually switch the network namespace */
6615         dev_net_set(dev, net);
6616 
6617         /* If there is an ifindex conflict assign a new one */
6618         if (__dev_get_by_index(net, dev->ifindex)) {
6619                 int iflink = (dev->iflink == dev->ifindex);
6620                 dev->ifindex = dev_new_index(net);
6621                 if (iflink)
6622                         dev->iflink = dev->ifindex;
6623         }
6624 
6625         /* Send a netdev-add uevent to the new namespace */
6626         kobject_uevent(&dev->dev.kobj, KOBJ_ADD);
6627 
6628         /* Fixup kobjects */
6629         err = device_rename(&dev->dev, dev->name);
6630         WARN_ON(err);
6631 
6632         /* Add the device back in the hashes */
6633         list_netdevice(dev);
6634 
6635         /* Notify protocols, that a new device appeared. */
6636         call_netdevice_notifiers(NETDEV_REGISTER, dev);
6637 
6638         /*
6639          *      Prevent userspace races by waiting until the network
6640          *      device is fully setup before sending notifications.
6641          */
6642         rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U, GFP_KERNEL);
6643 
6644         synchronize_net();
6645         err = 0;
6646 out:
6647         return err;
6648 }
6649 EXPORT_SYMBOL_GPL(dev_change_net_namespace);
6650 
6651 static int dev_cpu_callback(struct notifier_block *nfb,
6652                             unsigned long action,
6653                             void *ocpu)
6654 {
6655         struct sk_buff **list_skb;
6656         struct sk_buff *skb;
6657         unsigned int cpu, oldcpu = (unsigned long)ocpu;
6658         struct softnet_data *sd, *oldsd;
6659 
6660         if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
6661                 return NOTIFY_OK;
6662 
6663         local_irq_disable();
6664         cpu = smp_processor_id();
6665         sd = &per_cpu(softnet_data, cpu);
6666         oldsd = &per_cpu(softnet_data, oldcpu);
6667 
6668         /* Find end of our completion_queue. */
6669         list_skb = &sd->completion_queue;
6670         while (*list_skb)
6671                 list_skb = &(*list_skb)->next;
6672         /* Append completion queue from offline CPU. */
6673         *list_skb = oldsd->completion_queue;
6674         oldsd->completion_queue = NULL;
6675 
6676         /* Append output queue from offline CPU. */
6677         if (oldsd->output_queue) {
6678                 *sd->output_queue_tailp = oldsd->output_queue;
6679                 sd->output_queue_tailp = oldsd->output_queue_tailp;
6680                 oldsd->output_queue = NULL;
6681                 oldsd->output_queue_tailp = &oldsd->output_queue;
6682         }
6683         /* Append NAPI poll list from offline CPU. */
6684         if (!list_empty(&oldsd->poll_list)) {
6685                 list_splice_init(&oldsd->poll_list, &sd->poll_list);
6686                 raise_softirq_irqoff(NET_RX_SOFTIRQ);
6687         }
6688 
6689         raise_softirq_irqoff(NET_TX_SOFTIRQ);
6690         local_irq_enable();
6691 
6692         /* Process offline CPU's input_pkt_queue */
6693         while ((skb = __skb_dequeue(&oldsd->process_queue))) {
6694                 netif_rx_internal(skb);
6695                 input_queue_head_incr(oldsd);
6696         }
6697         while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
6698                 netif_rx_internal(skb);
6699                 input_queue_head_incr(oldsd);
6700         }
6701 
6702         return NOTIFY_OK;
6703 }
6704 
6705 
6706 /**
6707  *      netdev_increment_features - increment feature set by one
6708  *      @all: current feature set
6709  *      @one: new feature set
6710  *      @mask: mask feature set
6711  *
6712  *      Computes a new feature set after adding a device with feature set
6713  *      @one to the master device with current feature set @all.  Will not
6714  *      enable anything that is off in @mask. Returns the new feature set.
6715  */
6716 netdev_features_t netdev_increment_features(netdev_features_t all,
6717         netdev_features_t one, netdev_features_t mask)
6718 {
6719         if (mask & NETIF_F_GEN_CSUM)
6720                 mask |= NETIF_F_ALL_CSUM;
6721         mask |= NETIF_F_VLAN_CHALLENGED;
6722 
6723         all |= one & (NETIF_F_ONE_FOR_ALL|NETIF_F_ALL_CSUM) & mask;
6724         all &= one | ~NETIF_F_ALL_FOR_ALL;
6725 
6726         /* If one device supports hw checksumming, set for all. */
6727         if (all & NETIF_F_GEN_CSUM)
6728                 all &= ~(NETIF_F_ALL_CSUM & ~NETIF_F_GEN_CSUM);
6729 
6730         return all;
6731 }
6732 EXPORT_SYMBOL(netdev_increment_features);
6733 
6734 static struct hlist_head * __net_init netdev_create_hash(void)
6735 {
6736         int i;
6737         struct hlist_head *hash;
6738 
6739         hash = kmalloc(sizeof(*hash) * NETDEV_HASHENTRIES, GFP_KERNEL);
6740         if (hash != NULL)
6741                 for (i = 0; i < NETDEV_HASHENTRIES; i++)
6742                         INIT_HLIST_HEAD(&hash[i]);
6743 
6744         return hash;
6745 }
6746 
6747 /* Initialize per network namespace state */
6748 static int __net_init netdev_init(struct net *net)
6749 {
6750         if (net != &init_net)
6751                 INIT_LIST_HEAD(&net->dev_base_head);
6752 
6753         net->dev_name_head = netdev_create_hash();
6754         if (net->dev_name_head == NULL)
6755                 goto err_name;
6756 
6757         net->dev_index_head = netdev_create_hash();
6758         if (net->dev_index_head == NULL)
6759                 goto err_idx;
6760 
6761         return 0;
6762 
6763 err_idx:
6764         kfree(net->dev_name_head);
6765 err_name:
6766         return -ENOMEM;
6767 }
6768 
6769 /**
6770  *      netdev_drivername - network driver for the device
6771  *      @dev: network device
6772  *
6773  *      Determine network driver for device.
6774  */
6775 const char *netdev_drivername(const struct net_device *dev)
6776 {
6777         const struct device_driver *driver;
6778         const struct device *parent;
6779         const char *empty = "";
6780 
6781         parent = dev->dev.parent;
6782         if (!parent)
6783                 return empty;
6784 
6785         driver = parent->driver;
6786         if (driver && driver->name)
6787                 return driver->name;
6788         return empty;
6789 }
6790 
6791 static int __netdev_printk(const char *level, const struct net_device *dev,
6792                            struct va_format *vaf)
6793 {
6794         int r;
6795 
6796         if (dev && dev->dev.parent) {
6797                 r = dev_printk_emit(level[1] - '',
6798                                     dev->dev.parent,
6799                                     "%s %s %s: %pV",
6800                                     dev_driver_string(dev->dev.parent),
6801                                     dev_name(dev->dev.parent),
6802                                     netdev_name(dev), vaf);
6803         } else if (dev) {
6804                 r = printk("%s%s: %pV", level, netdev_name(dev), vaf);
6805         } else {
6806                 r = printk("%s(NULL net_device): %pV", level, vaf);
6807         }
6808 
6809         return r;
6810 }
6811 
6812 int netdev_printk(const char *level, const struct net_device *dev,
6813                   const char *format, ...)
6814 {
6815         struct va_format vaf;
6816         va_list args;
6817         int r;
6818 
6819         va_start(args, format);
6820 
6821         vaf.fmt = format;
6822         vaf.va = &args;
6823 
6824         r = __netdev_printk(level, dev, &vaf);
6825 
6826         va_end(args);
6827 
6828         return r;
6829 }
6830 EXPORT_SYMBOL(netdev_printk);
6831 
6832 #define define_netdev_printk_level(func, level)                 \
6833 int func(const struct net_device *dev, const char *fmt, ...)    \
6834 {                                                               \
6835         int r;                                                  \
6836         struct va_format vaf;                                   \
6837         va_list args;                                           \
6838                                                                 \
6839         va_start(args, fmt);                                    \
6840                                                                 \
6841         vaf.fmt = fmt;                                          \
6842         vaf.va = &args;                                         \
6843                                                                 \
6844         r = __netdev_printk(level, dev, &vaf);                  \
6845                                                                 \
6846         va_end(args);                                           \
6847                                                                 \
6848         return r;                                               \
6849 }                                                               \
6850 EXPORT_SYMBOL(func);
6851 
6852 define_netdev_printk_level(netdev_emerg, KERN_EMERG);
6853 define_netdev_printk_level(netdev_alert, KERN_ALERT);
6854 define_netdev_printk_level(netdev_crit, KERN_CRIT);
6855 define_netdev_printk_level(netdev_err, KERN_ERR);
6856 define_netdev_printk_level(netdev_warn, KERN_WARNING);
6857 define_netdev_printk_level(netdev_notice, KERN_NOTICE);
6858 define_netdev_printk_level(netdev_info, KERN_INFO);
6859 
6860 static void __net_exit netdev_exit(struct net *net)
6861 {
6862         kfree(net->dev_name_head);
6863         kfree(net->dev_index_head);
6864 }
6865 
6866 static struct pernet_operations __net_initdata netdev_net_ops = {
6867         .init = netdev_init,
6868         .exit = netdev_exit,
6869 };
6870 
6871 static void __net_exit default_device_exit(struct net *net)
6872 {
6873         struct net_device *dev, *aux;
6874         /*
6875          * Push all migratable network devices back to the
6876          * initial network namespace
6877          */
6878         rtnl_lock();
6879         for_each_netdev_safe(net, dev, aux) {
6880                 int err;
6881                 char fb_name[IFNAMSIZ];
6882 
6883                 /* Ignore unmoveable devices (i.e. loopback) */
6884                 if (dev->features & NETIF_F_NETNS_LOCAL)
6885                         continue;
6886 
6887                 /* Leave virtual devices for the generic cleanup */
6888                 if (dev->rtnl_link_ops)
6889                         continue;
6890 
6891                 /* Push remaining network devices to init_net */
6892                 snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex);
6893                 err = dev_change_net_namespace(dev, &init_net, fb_name);
6894                 if (err) {
6895                         pr_emerg("%s: failed to move %s to init_net: %d\n",
6896                                  __func__, dev->name, err);
6897                         BUG();
6898                 }
6899         }
6900         rtnl_unlock();
6901 }
6902 
6903 static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
6904 {
6905         /* Return with the rtnl_lock held when there are no network
6906          * devices unregistering in any network namespace in net_list.
6907          */
6908         struct net *net;
6909         bool unregistering;
6910         DEFINE_WAIT(wait);
6911 
6912         for (;;) {
6913                 prepare_to_wait(&netdev_unregistering_wq, &wait,
6914                                 TASK_UNINTERRUPTIBLE);
6915                 unregistering = false;
6916                 rtnl_lock();
6917                 list_for_each_entry(net, net_list, exit_list) {
6918                         if (net->dev_unreg_count > 0) {
6919                                 unregistering = true;
6920                                 break;
6921                         }
6922                 }
6923                 if (!unregistering)
6924                         break;
6925                 __rtnl_unlock();
6926                 schedule();
6927         }
6928         finish_wait(&netdev_unregistering_wq, &wait);
6929 }
6930 
6931 static void __net_exit default_device_exit_batch(struct list_head *net_list)
6932 {
6933         /* At exit all network devices most be removed from a network
6934          * namespace.  Do this in the reverse order of registration.
6935          * Do this across as many network namespaces as possible to
6936          * improve batching efficiency.
6937          */
6938         struct net_device *dev;
6939         struct net *net;
6940         LIST_HEAD(dev_kill_list);
6941 
6942         /* To prevent network device cleanup code from dereferencing
6943          * loopback devices or network devices that have been freed
6944          * wait here for all pending unregistrations to complete,
6945          * before unregistring the loopback device and allowing the
6946          * network namespace be freed.
6947          *
6948          * The netdev todo list containing all network devices
6949          * unregistrations that happen in default_device_exit_batch
6950          * will run in the rtnl_unlock() at the end of
6951          * default_device_exit_batch.
6952          */
6953         rtnl_lock_unregistering(net_list);
6954         list_for_each_entry(net, net_list, exit_list) {
6955                 for_each_netdev_reverse(net, dev) {
6956                         if (dev->rtnl_link_ops)
6957                                 dev->rtnl_link_ops->dellink(dev, &dev_kill_list);
6958                         else
6959                                 unregister_netdevice_queue(dev, &dev_kill_list);
6960                 }
6961         }
6962         unregister_netdevice_many(&dev_kill_list);
6963         list_del(&dev_kill_list);
6964         rtnl_unlock();
6965 }
6966 
6967 static struct pernet_operations __net_initdata default_device_ops = {
6968         .exit = default_device_exit,
6969         .exit_batch = default_device_exit_batch,
6970 };
6971 
6972 /*
6973  *      Initialize the DEV module. At boot time this walks the device list and
6974  *      unhooks any devices that fail to initialise (normally hardware not
6975  *      present) and leaves us with a valid list of present and active devices.
6976  *
6977  */
6978 
6979 /*
6980  *       This is called single threaded during boot, so no need
6981  *       to take the rtnl semaphore.
6982  */
6983 static int __init net_dev_init(void)
6984 {
6985         int i, rc = -ENOMEM;
6986 
6987         BUG_ON(!dev_boot_phase);
6988 
6989         if (dev_proc_init())
6990                 goto out;
6991 
6992         if (netdev_kobject_init())
6993                 goto out;
6994 
6995         INIT_LIST_HEAD(&ptype_all);
6996         for (i = 0; i < PTYPE_HASH_SIZE; i++)
6997                 INIT_LIST_HEAD(&ptype_base[i]);
6998 
6999         INIT_LIST_HEAD(&offload_base);
7000 
7001         if (register_pernet_subsys(&netdev_net_ops))
7002                 goto out;
7003 
7004         /*
7005          *      Initialise the packet receive queues.
7006          */
7007 
7008         for_each_possible_cpu(i) {
7009                 struct softnet_data *sd = &per_cpu(softnet_data, i);
7010 
7011                 skb_queue_head_init(&sd->input_pkt_queue);
7012                 skb_queue_head_init(&sd->process_queue);
7013                 INIT_LIST_HEAD(&sd->poll_list);
7014                 sd->output_queue_tailp = &sd->output_queue;
7015 #ifdef CONFIG_RPS
7016                 sd->csd.func = rps_trigger_softirq;
7017                 sd->csd.info = sd;
7018                 sd->cpu = i;
7019 #endif
7020 
7021                 sd->backlog.poll = process_backlog;
7022                 sd->backlog.weight = weight_p;
7023         }
7024 
7025         dev_boot_phase = 0;
7026 
7027         /* The loopback device is special if any other network devices
7028          * is present in a network namespace the loopback device must
7029          * be present. Since we now dynamically allocate and free the
7030          * loopback device ensure this invariant is maintained by
7031          * keeping the loopback device as the first device on the
7032          * list of network devices.  Ensuring the loopback devices
7033          * is the first device that appears and the last network device
7034          * that disappears.
7035          */
7036         if (register_pernet_device(&loopback_net_ops))
7037                 goto out;
7038 
7039         if (register_pernet_device(&default_device_ops))
7040                 goto out;
7041 
7042         open_softirq(NET_TX_SOFTIRQ, net_tx_action);
7043         open_softirq(NET_RX_SOFTIRQ, net_rx_action);
7044 
7045         hotcpu_notifier(dev_cpu_callback, 0);
7046         dst_init();
7047         rc = 0;
7048 out:
7049         return rc;
7050 }
7051 
7052 subsys_initcall(net_dev_init);
7053 

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