Linux/include/net/sock.h

  1 /*
  2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  3  *              operating system.  INET is implemented using the  BSD Socket
  4  *              interface as the means of communication with the user level.
  5  *
  6  *              Definitions for the AF_INET socket handler.
  7  *
  8  * Version:     @(#)sock.h      1.0.4   05/13/93
  9  *
 10  * Authors:     Ross Biro
 11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 12  *              Corey Minyard <wf-rch!minyard@relay.EU.net>
 13  *              Florian La Roche <flla@stud.uni-sb.de>
 14  *
 15  * Fixes:
 16  *              Alan Cox        :       Volatiles in skbuff pointers. See
 17  *                                      skbuff comments. May be overdone,
 18  *                                      better to prove they can be removed
 19  *                                      than the reverse.
 20  *              Alan Cox        :       Added a zapped field for tcp to note
 21  *                                      a socket is reset and must stay shut up
 22  *              Alan Cox        :       New fields for options
 23  *      Pauline Middelink       :       identd support
 24  *              Alan Cox        :       Eliminate low level recv/recvfrom
 25  *              David S. Miller :       New socket lookup architecture.
 26  *              Steve Whitehouse:       Default routines for sock_ops
 27  *              Arnaldo C. Melo :       removed net_pinfo, tp_pinfo and made
 28  *                                      protinfo be just a void pointer, as the
 29  *                                      protocol specific parts were moved to
 30  *                                      respective headers and ipv4/v6, etc now
 31  *                                      use private slabcaches for its socks
 32  *              Pedro Hortas    :       New flags field for socket options
 33  *
 34  *
 35  *              This program is free software; you can redistribute it and/or
 36  *              modify it under the terms of the GNU General Public License
 37  *              as published by the Free Software Foundation; either version
 38  *              2 of the License, or (at your option) any later version.
 39  */
 40 #ifndef _SOCK_H
 41 #define _SOCK_H
 42 
 43 #include <linux/hardirq.h>
 44 #include <linux/kernel.h>
 45 #include <linux/list.h>
 46 #include <linux/list_nulls.h>
 47 #include <linux/timer.h>
 48 #include <linux/cache.h>
 49 #include <linux/bitops.h>
 50 #include <linux/lockdep.h>
 51 #include <linux/netdevice.h>
 52 #include <linux/skbuff.h>       /* struct sk_buff */
 53 #include <linux/mm.h>
 54 #include <linux/security.h>
 55 #include <linux/slab.h>
 56 #include <linux/uaccess.h>
 57 #include <linux/memcontrol.h>
 58 #include <linux/res_counter.h>
 59 #include <linux/static_key.h>
 60 #include <linux/aio.h>
 61 #include <linux/sched.h>
 62 
 63 #include <linux/filter.h>
 64 #include <linux/rculist_nulls.h>
 65 #include <linux/poll.h>
 66 
 67 #include <linux/atomic.h>
 68 #include <net/dst.h>
 69 #include <net/checksum.h>
 70 
 71 struct cgroup;
 72 struct cgroup_subsys;
 73 #ifdef CONFIG_NET
 74 int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss);
 75 void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg);
 76 #else
 77 static inline
 78 int mem_cgroup_sockets_init(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
 79 {
 80         return 0;
 81 }
 82 static inline
 83 void mem_cgroup_sockets_destroy(struct mem_cgroup *memcg)
 84 {
 85 }
 86 #endif
 87 /*
 88  * This structure really needs to be cleaned up.
 89  * Most of it is for TCP, and not used by any of
 90  * the other protocols.
 91  */
 92 
 93 /* Define this to get the SOCK_DBG debugging facility. */
 94 #define SOCK_DEBUGGING
 95 #ifdef SOCK_DEBUGGING
 96 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
 97                                         printk(KERN_DEBUG msg); } while (0)
 98 #else
 99 /* Validate arguments and do nothing */
100 static inline __printf(2, 3)
101 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
102 {
103 }
104 #endif
105 
106 /* This is the per-socket lock.  The spinlock provides a synchronization
107  * between user contexts and software interrupt processing, whereas the
108  * mini-semaphore synchronizes multiple users amongst themselves.
109  */
110 typedef struct {
111         spinlock_t              slock;
112         int                     owned;
113         wait_queue_head_t       wq;
114         /*
115          * We express the mutex-alike socket_lock semantics
116          * to the lock validator by explicitly managing
117          * the slock as a lock variant (in addition to
118          * the slock itself):
119          */
120 #ifdef CONFIG_DEBUG_LOCK_ALLOC
121         struct lockdep_map dep_map;
122 #endif
123 } socket_lock_t;
124 
125 struct sock;
126 struct proto;
127 struct net;
128 
129 typedef __u32 __bitwise __portpair;
130 typedef __u64 __bitwise __addrpair;
131 
132 /**
133  *      struct sock_common - minimal network layer representation of sockets
134  *      @skc_daddr: Foreign IPv4 addr
135  *      @skc_rcv_saddr: Bound local IPv4 addr
136  *      @skc_hash: hash value used with various protocol lookup tables
137  *      @skc_u16hashes: two u16 hash values used by UDP lookup tables
138  *      @skc_dport: placeholder for inet_dport/tw_dport
139  *      @skc_num: placeholder for inet_num/tw_num
140  *      @skc_family: network address family
141  *      @skc_state: Connection state
142  *      @skc_reuse: %SO_REUSEADDR setting
143  *      @skc_reuseport: %SO_REUSEPORT setting
144  *      @skc_bound_dev_if: bound device index if != 0
145  *      @skc_bind_node: bind hash linkage for various protocol lookup tables
146  *      @skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
147  *      @skc_prot: protocol handlers inside a network family
148  *      @skc_net: reference to the network namespace of this socket
149  *      @skc_node: main hash linkage for various protocol lookup tables
150  *      @skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
151  *      @skc_tx_queue_mapping: tx queue number for this connection
152  *      @skc_refcnt: reference count
153  *
154  *      This is the minimal network layer representation of sockets, the header
155  *      for struct sock and struct inet_timewait_sock.
156  */
157 struct sock_common {
158         /* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
159          * address on 64bit arches : cf INET_MATCH() and INET_TW_MATCH()
160          */
161         union {
162                 __addrpair      skc_addrpair;
163                 struct {
164                         __be32  skc_daddr;
165                         __be32  skc_rcv_saddr;
166                 };
167         };
168         union  {
169                 unsigned int    skc_hash;
170                 __u16           skc_u16hashes[2];
171         };
172         /* skc_dport && skc_num must be grouped as well */
173         union {
174                 __portpair      skc_portpair;
175                 struct {
176                         __be16  skc_dport;
177                         __u16   skc_num;
178                 };
179         };
180 
181         unsigned short          skc_family;
182         volatile unsigned char  skc_state;
183         unsigned char           skc_reuse:4;
184         unsigned char           skc_reuseport:4;
185         int                     skc_bound_dev_if;
186         union {
187                 struct hlist_node       skc_bind_node;
188                 struct hlist_nulls_node skc_portaddr_node;
189         };
190         struct proto            *skc_prot;
191 #ifdef CONFIG_NET_NS
192         struct net              *skc_net;
193 #endif
194         /*
195          * fields between dontcopy_begin/dontcopy_end
196          * are not copied in sock_copy()
197          */
198         /* private: */
199         int                     skc_dontcopy_begin[0];
200         /* public: */
201         union {
202                 struct hlist_node       skc_node;
203                 struct hlist_nulls_node skc_nulls_node;
204         };
205         int                     skc_tx_queue_mapping;
206         atomic_t                skc_refcnt;
207         /* private: */
208         int                     skc_dontcopy_end[0];
209         /* public: */
210 };
211 
212 struct cg_proto;
213 /**
214   *     struct sock - network layer representation of sockets
215   *     @__sk_common: shared layout with inet_timewait_sock
216   *     @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
217   *     @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
218   *     @sk_lock:       synchronizer
219   *     @sk_rcvbuf: size of receive buffer in bytes
220   *     @sk_wq: sock wait queue and async head
221   *     @sk_rx_dst: receive input route used by early tcp demux
222   *     @sk_dst_cache: destination cache
223   *     @sk_dst_lock: destination cache lock
224   *     @sk_policy: flow policy
225   *     @sk_receive_queue: incoming packets
226   *     @sk_wmem_alloc: transmit queue bytes committed
227   *     @sk_write_queue: Packet sending queue
228   *     @sk_async_wait_queue: DMA copied packets
229   *     @sk_omem_alloc: "o" is "option" or "other"
230   *     @sk_wmem_queued: persistent queue size
231   *     @sk_forward_alloc: space allocated forward
232   *     @sk_allocation: allocation mode
233   *     @sk_sndbuf: size of send buffer in bytes
234   *     @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
235   *                %SO_OOBINLINE settings, %SO_TIMESTAMPING settings
236   *     @sk_no_check: %SO_NO_CHECK setting, whether or not checkup packets
237   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
238   *     @sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
239   *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
240   *     @sk_gso_max_size: Maximum GSO segment size to build
241   *     @sk_gso_max_segs: Maximum number of GSO segments
242   *     @sk_lingertime: %SO_LINGER l_linger setting
243   *     @sk_backlog: always used with the per-socket spinlock held
244   *     @sk_callback_lock: used with the callbacks in the end of this struct
245   *     @sk_error_queue: rarely used
246   *     @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
247   *                       IPV6_ADDRFORM for instance)
248   *     @sk_err: last error
249   *     @sk_err_soft: errors that don't cause failure but are the cause of a
250   *                   persistent failure not just 'timed out'
251   *     @sk_drops: raw/udp drops counter
252   *     @sk_ack_backlog: current listen backlog
253   *     @sk_max_ack_backlog: listen backlog set in listen()
254   *     @sk_priority: %SO_PRIORITY setting
255   *     @sk_cgrp_prioidx: socket group's priority map index
256   *     @sk_type: socket type (%SOCK_STREAM, etc)
257   *     @sk_protocol: which protocol this socket belongs in this network family
258   *     @sk_peer_pid: &struct pid for this socket's peer
259   *     @sk_peer_cred: %SO_PEERCRED setting
260   *     @sk_rcvlowat: %SO_RCVLOWAT setting
261   *     @sk_rcvtimeo: %SO_RCVTIMEO setting
262   *     @sk_sndtimeo: %SO_SNDTIMEO setting
263   *     @sk_rxhash: flow hash received from netif layer
264   *     @sk_filter: socket filtering instructions
265   *     @sk_protinfo: private area, net family specific, when not using slab
266   *     @sk_timer: sock cleanup timer
267   *     @sk_stamp: time stamp of last packet received
268   *     @sk_socket: Identd and reporting IO signals
269   *     @sk_user_data: RPC layer private data
270   *     @sk_frag: cached page frag
271   *     @sk_peek_off: current peek_offset value
272   *     @sk_send_head: front of stuff to transmit
273   *     @sk_security: used by security modules
274   *     @sk_mark: generic packet mark
275   *     @sk_classid: this socket's cgroup classid
276   *     @sk_cgrp: this socket's cgroup-specific proto data
277   *     @sk_write_pending: a write to stream socket waits to start
278   *     @sk_state_change: callback to indicate change in the state of the sock
279   *     @sk_data_ready: callback to indicate there is data to be processed
280   *     @sk_write_space: callback to indicate there is bf sending space available
281   *     @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
282   *     @sk_backlog_rcv: callback to process the backlog
283   *     @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
284  */
285 struct sock {
286         /*
287          * Now struct inet_timewait_sock also uses sock_common, so please just
288          * don't add nothing before this first member (__sk_common) --acme
289          */
290         struct sock_common      __sk_common;
291 #define sk_node                 __sk_common.skc_node
292 #define sk_nulls_node           __sk_common.skc_nulls_node
293 #define sk_refcnt               __sk_common.skc_refcnt
294 #define sk_tx_queue_mapping     __sk_common.skc_tx_queue_mapping
295 
296 #define sk_dontcopy_begin       __sk_common.skc_dontcopy_begin
297 #define sk_dontcopy_end         __sk_common.skc_dontcopy_end
298 #define sk_hash                 __sk_common.skc_hash
299 #define sk_family               __sk_common.skc_family
300 #define sk_state                __sk_common.skc_state
301 #define sk_reuse                __sk_common.skc_reuse
302 #define sk_reuseport            __sk_common.skc_reuseport
303 #define sk_bound_dev_if         __sk_common.skc_bound_dev_if
304 #define sk_bind_node            __sk_common.skc_bind_node
305 #define sk_prot                 __sk_common.skc_prot
306 #define sk_net                  __sk_common.skc_net
307         socket_lock_t           sk_lock;
308         struct sk_buff_head     sk_receive_queue;
309         /*
310          * The backlog queue is special, it is always used with
311          * the per-socket spinlock held and requires low latency
312          * access. Therefore we special case it's implementation.
313          * Note : rmem_alloc is in this structure to fill a hole
314          * on 64bit arches, not because its logically part of
315          * backlog.
316          */
317         struct {
318                 atomic_t        rmem_alloc;
319                 int             len;
320                 struct sk_buff  *head;
321                 struct sk_buff  *tail;
322         } sk_backlog;
323 #define sk_rmem_alloc sk_backlog.rmem_alloc
324         int                     sk_forward_alloc;
325 #ifdef CONFIG_RPS
326         __u32                   sk_rxhash;
327 #endif
328         atomic_t                sk_drops;
329         int                     sk_rcvbuf;
330 
331         struct sk_filter __rcu  *sk_filter;
332         struct socket_wq __rcu  *sk_wq;
333 
334 #ifdef CONFIG_NET_DMA
335         struct sk_buff_head     sk_async_wait_queue;
336 #endif
337 
338 #ifdef CONFIG_XFRM
339         struct xfrm_policy      *sk_policy[2];
340 #endif
341         unsigned long           sk_flags;
342         struct dst_entry        *sk_rx_dst;
343         struct dst_entry __rcu  *sk_dst_cache;
344         spinlock_t              sk_dst_lock;
345         atomic_t                sk_wmem_alloc;
346         atomic_t                sk_omem_alloc;
347         int                     sk_sndbuf;
348         struct sk_buff_head     sk_write_queue;
349         kmemcheck_bitfield_begin(flags);
350         unsigned int            sk_shutdown  : 2,
351                                 sk_no_check  : 2,
352                                 sk_userlocks : 4,
353                                 sk_protocol  : 8,
354                                 sk_type      : 16;
355         kmemcheck_bitfield_end(flags);
356         int                     sk_wmem_queued;
357         gfp_t                   sk_allocation;
358         netdev_features_t       sk_route_caps;
359         netdev_features_t       sk_route_nocaps;
360         int                     sk_gso_type;
361         unsigned int            sk_gso_max_size;
362         u16                     sk_gso_max_segs;
363         int                     sk_rcvlowat;
364         unsigned long           sk_lingertime;
365         struct sk_buff_head     sk_error_queue;
366         struct proto            *sk_prot_creator;
367         rwlock_t                sk_callback_lock;
368         int                     sk_err,
369                                 sk_err_soft;
370         unsigned short          sk_ack_backlog;
371         unsigned short          sk_max_ack_backlog;
372         __u32                   sk_priority;
373 #if IS_ENABLED(CONFIG_NETPRIO_CGROUP)
374         __u32                   sk_cgrp_prioidx;
375 #endif
376         struct pid              *sk_peer_pid;
377         const struct cred       *sk_peer_cred;
378         long                    sk_rcvtimeo;
379         long                    sk_sndtimeo;
380         void                    *sk_protinfo;
381         struct timer_list       sk_timer;
382         ktime_t                 sk_stamp;
383         struct socket           *sk_socket;
384         void                    *sk_user_data;
385         struct page_frag        sk_frag;
386         struct sk_buff          *sk_send_head;
387         __s32                   sk_peek_off;
388         int                     sk_write_pending;
389 #ifdef CONFIG_SECURITY
390         void                    *sk_security;
391 #endif
392         __u32                   sk_mark;
393         u32                     sk_classid;
394         struct cg_proto         *sk_cgrp;
395         void                    (*sk_state_change)(struct sock *sk);
396         void                    (*sk_data_ready)(struct sock *sk, int bytes);
397         void                    (*sk_write_space)(struct sock *sk);
398         void                    (*sk_error_report)(struct sock *sk);
399         int                     (*sk_backlog_rcv)(struct sock *sk,
400                                                   struct sk_buff *skb);
401         void                    (*sk_destruct)(struct sock *sk);
402 };
403 
404 /*
405  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
406  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
407  * on a socket means that the socket will reuse everybody else's port
408  * without looking at the other's sk_reuse value.
409  */
410 
411 #define SK_NO_REUSE     0
412 #define SK_CAN_REUSE    1
413 #define SK_FORCE_REUSE  2
414 
415 static inline int sk_peek_offset(struct sock *sk, int flags)
416 {
417         if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))
418                 return sk->sk_peek_off;
419         else
420                 return 0;
421 }
422 
423 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
424 {
425         if (sk->sk_peek_off >= 0) {
426                 if (sk->sk_peek_off >= val)
427                         sk->sk_peek_off -= val;
428                 else
429                         sk->sk_peek_off = 0;
430         }
431 }
432 
433 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
434 {
435         if (sk->sk_peek_off >= 0)
436                 sk->sk_peek_off += val;
437 }
438 
439 /*
440  * Hashed lists helper routines
441  */
442 static inline struct sock *sk_entry(const struct hlist_node *node)
443 {
444         return hlist_entry(node, struct sock, sk_node);
445 }
446 
447 static inline struct sock *__sk_head(const struct hlist_head *head)
448 {
449         return hlist_entry(head->first, struct sock, sk_node);
450 }
451 
452 static inline struct sock *sk_head(const struct hlist_head *head)
453 {
454         return hlist_empty(head) ? NULL : __sk_head(head);
455 }
456 
457 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
458 {
459         return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
460 }
461 
462 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
463 {
464         return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
465 }
466 
467 static inline struct sock *sk_next(const struct sock *sk)
468 {
469         return sk->sk_node.next ?
470                 hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
471 }
472 
473 static inline struct sock *sk_nulls_next(const struct sock *sk)
474 {
475         return (!is_a_nulls(sk->sk_nulls_node.next)) ?
476                 hlist_nulls_entry(sk->sk_nulls_node.next,
477                                   struct sock, sk_nulls_node) :
478                 NULL;
479 }
480 
481 static inline bool sk_unhashed(const struct sock *sk)
482 {
483         return hlist_unhashed(&sk->sk_node);
484 }
485 
486 static inline bool sk_hashed(const struct sock *sk)
487 {
488         return !sk_unhashed(sk);
489 }
490 
491 static inline void sk_node_init(struct hlist_node *node)
492 {
493         node->pprev = NULL;
494 }
495 
496 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
497 {
498         node->pprev = NULL;
499 }
500 
501 static inline void __sk_del_node(struct sock *sk)
502 {
503         __hlist_del(&sk->sk_node);
504 }
505 
506 /* NB: equivalent to hlist_del_init_rcu */
507 static inline bool __sk_del_node_init(struct sock *sk)
508 {
509         if (sk_hashed(sk)) {
510                 __sk_del_node(sk);
511                 sk_node_init(&sk->sk_node);
512                 return true;
513         }
514         return false;
515 }
516 
517 /* Grab socket reference count. This operation is valid only
518    when sk is ALREADY grabbed f.e. it is found in hash table
519    or a list and the lookup is made under lock preventing hash table
520    modifications.
521  */
522 
523 static inline void sock_hold(struct sock *sk)
524 {
525         atomic_inc(&sk->sk_refcnt);
526 }
527 
528 /* Ungrab socket in the context, which assumes that socket refcnt
529    cannot hit zero, f.e. it is true in context of any socketcall.
530  */
531 static inline void __sock_put(struct sock *sk)
532 {
533         atomic_dec(&sk->sk_refcnt);
534 }
535 
536 static inline bool sk_del_node_init(struct sock *sk)
537 {
538         bool rc = __sk_del_node_init(sk);
539 
540         if (rc) {
541                 /* paranoid for a while -acme */
542                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
543                 __sock_put(sk);
544         }
545         return rc;
546 }
547 #define sk_del_node_init_rcu(sk)        sk_del_node_init(sk)
548 
549 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
550 {
551         if (sk_hashed(sk)) {
552                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
553                 return true;
554         }
555         return false;
556 }
557 
558 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
559 {
560         bool rc = __sk_nulls_del_node_init_rcu(sk);
561 
562         if (rc) {
563                 /* paranoid for a while -acme */
564                 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
565                 __sock_put(sk);
566         }
567         return rc;
568 }
569 
570 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
571 {
572         hlist_add_head(&sk->sk_node, list);
573 }
574 
575 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
576 {
577         sock_hold(sk);
578         __sk_add_node(sk, list);
579 }
580 
581 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
582 {
583         sock_hold(sk);
584         hlist_add_head_rcu(&sk->sk_node, list);
585 }
586 
587 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
588 {
589         hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
590 }
591 
592 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
593 {
594         sock_hold(sk);
595         __sk_nulls_add_node_rcu(sk, list);
596 }
597 
598 static inline void __sk_del_bind_node(struct sock *sk)
599 {
600         __hlist_del(&sk->sk_bind_node);
601 }
602 
603 static inline void sk_add_bind_node(struct sock *sk,
604                                         struct hlist_head *list)
605 {
606         hlist_add_head(&sk->sk_bind_node, list);
607 }
608 
609 #define sk_for_each(__sk, list) \
610         hlist_for_each_entry(__sk, list, sk_node)
611 #define sk_for_each_rcu(__sk, list) \
612         hlist_for_each_entry_rcu(__sk, list, sk_node)
613 #define sk_nulls_for_each(__sk, node, list) \
614         hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
615 #define sk_nulls_for_each_rcu(__sk, node, list) \
616         hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
617 #define sk_for_each_from(__sk) \
618         hlist_for_each_entry_from(__sk, sk_node)
619 #define sk_nulls_for_each_from(__sk, node) \
620         if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
621                 hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
622 #define sk_for_each_safe(__sk, tmp, list) \
623         hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
624 #define sk_for_each_bound(__sk, list) \
625         hlist_for_each_entry(__sk, list, sk_bind_node)
626 
627 static inline struct user_namespace *sk_user_ns(struct sock *sk)
628 {
629         /* Careful only use this in a context where these parameters
630          * can not change and must all be valid, such as recvmsg from
631          * userspace.
632          */
633         return sk->sk_socket->file->f_cred->user_ns;
634 }
635 
636 /* Sock flags */
637 enum sock_flags {
638         SOCK_DEAD,
639         SOCK_DONE,
640         SOCK_URGINLINE,
641         SOCK_KEEPOPEN,
642         SOCK_LINGER,
643         SOCK_DESTROY,
644         SOCK_BROADCAST,
645         SOCK_TIMESTAMP,
646         SOCK_ZAPPED,
647         SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
648         SOCK_DBG, /* %SO_DEBUG setting */
649         SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
650         SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
651         SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
652         SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
653         SOCK_MEMALLOC, /* VM depends on this socket for swapping */
654         SOCK_TIMESTAMPING_TX_HARDWARE,  /* %SOF_TIMESTAMPING_TX_HARDWARE */
655         SOCK_TIMESTAMPING_TX_SOFTWARE,  /* %SOF_TIMESTAMPING_TX_SOFTWARE */
656         SOCK_TIMESTAMPING_RX_HARDWARE,  /* %SOF_TIMESTAMPING_RX_HARDWARE */
657         SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
658         SOCK_TIMESTAMPING_SOFTWARE,     /* %SOF_TIMESTAMPING_SOFTWARE */
659         SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */
660         SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
661         SOCK_FASYNC, /* fasync() active */
662         SOCK_RXQ_OVFL,
663         SOCK_ZEROCOPY, /* buffers from userspace */
664         SOCK_WIFI_STATUS, /* push wifi status to userspace */
665         SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
666                      * Will use last 4 bytes of packet sent from
667                      * user-space instead.
668                      */
669         SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
670         SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
671 };
672 
673 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
674 {
675         nsk->sk_flags = osk->sk_flags;
676 }
677 
678 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
679 {
680         __set_bit(flag, &sk->sk_flags);
681 }
682 
683 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
684 {
685         __clear_bit(flag, &sk->sk_flags);
686 }
687 
688 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
689 {
690         return test_bit(flag, &sk->sk_flags);
691 }
692 
693 #ifdef CONFIG_NET
694 extern struct static_key memalloc_socks;
695 static inline int sk_memalloc_socks(void)
696 {
697         return static_key_false(&memalloc_socks);
698 }
699 #else
700 
701 static inline int sk_memalloc_socks(void)
702 {
703         return 0;
704 }
705 
706 #endif
707 
708 static inline gfp_t sk_gfp_atomic(struct sock *sk, gfp_t gfp_mask)
709 {
710         return GFP_ATOMIC | (sk->sk_allocation & __GFP_MEMALLOC);
711 }
712 
713 static inline void sk_acceptq_removed(struct sock *sk)
714 {
715         sk->sk_ack_backlog--;
716 }
717 
718 static inline void sk_acceptq_added(struct sock *sk)
719 {
720         sk->sk_ack_backlog++;
721 }
722 
723 static inline bool sk_acceptq_is_full(const struct sock *sk)
724 {
725         return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
726 }
727 
728 /*
729  * Compute minimal free write space needed to queue new packets.
730  */
731 static inline int sk_stream_min_wspace(const struct sock *sk)
732 {
733         return sk->sk_wmem_queued >> 1;
734 }
735 
736 static inline int sk_stream_wspace(const struct sock *sk)
737 {
738         return sk->sk_sndbuf - sk->sk_wmem_queued;
739 }
740 
741 extern void sk_stream_write_space(struct sock *sk);
742 
743 static inline bool sk_stream_memory_free(const struct sock *sk)
744 {
745         return sk->sk_wmem_queued < sk->sk_sndbuf;
746 }
747 
748 /* OOB backlog add */
749 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
750 {
751         /* dont let skb dst not refcounted, we are going to leave rcu lock */
752         skb_dst_force(skb);
753 
754         if (!sk->sk_backlog.tail)
755                 sk->sk_backlog.head = skb;
756         else
757                 sk->sk_backlog.tail->next = skb;
758 
759         sk->sk_backlog.tail = skb;
760         skb->next = NULL;
761 }
762 
763 /*
764  * Take into account size of receive queue and backlog queue
765  * Do not take into account this skb truesize,
766  * to allow even a single big packet to come.
767  */
768 static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb,
769                                      unsigned int limit)
770 {
771         unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
772 
773         return qsize > limit;
774 }
775 
776 /* The per-socket spinlock must be held here. */
777 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
778                                               unsigned int limit)
779 {
780         if (sk_rcvqueues_full(sk, skb, limit))
781                 return -ENOBUFS;
782 
783         __sk_add_backlog(sk, skb);
784         sk->sk_backlog.len += skb->truesize;
785         return 0;
786 }
787 
788 extern int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
789 
790 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
791 {
792         if (sk_memalloc_socks() && skb_pfmemalloc(skb))
793                 return __sk_backlog_rcv(sk, skb);
794 
795         return sk->sk_backlog_rcv(sk, skb);
796 }
797 
798 static inline void sock_rps_record_flow(const struct sock *sk)
799 {
800 #ifdef CONFIG_RPS
801         struct rps_sock_flow_table *sock_flow_table;
802 
803         rcu_read_lock();
804         sock_flow_table = rcu_dereference(rps_sock_flow_table);
805         rps_record_sock_flow(sock_flow_table, sk->sk_rxhash);
806         rcu_read_unlock();
807 #endif
808 }
809 
810 static inline void sock_rps_reset_flow(const struct sock *sk)
811 {
812 #ifdef CONFIG_RPS
813         struct rps_sock_flow_table *sock_flow_table;
814 
815         rcu_read_lock();
816         sock_flow_table = rcu_dereference(rps_sock_flow_table);
817         rps_reset_sock_flow(sock_flow_table, sk->sk_rxhash);
818         rcu_read_unlock();
819 #endif
820 }
821 
822 static inline void sock_rps_save_rxhash(struct sock *sk,
823                                         const struct sk_buff *skb)
824 {
825 #ifdef CONFIG_RPS
826         if (unlikely(sk->sk_rxhash != skb->rxhash)) {
827                 sock_rps_reset_flow(sk);
828                 sk->sk_rxhash = skb->rxhash;
829         }
830 #endif
831 }
832 
833 static inline void sock_rps_reset_rxhash(struct sock *sk)
834 {
835 #ifdef CONFIG_RPS
836         sock_rps_reset_flow(sk);
837         sk->sk_rxhash = 0;
838 #endif
839 }
840 
841 #define sk_wait_event(__sk, __timeo, __condition)                       \
842         ({      int __rc;                                               \
843                 release_sock(__sk);                                     \
844                 __rc = __condition;                                     \
845                 if (!__rc) {                                            \
846                         *(__timeo) = schedule_timeout(*(__timeo));      \
847                 }                                                       \
848                 lock_sock(__sk);                                        \
849                 __rc = __condition;                                     \
850                 __rc;                                                   \
851         })
852 
853 extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
854 extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
855 extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
856 extern int sk_stream_error(struct sock *sk, int flags, int err);
857 extern void sk_stream_kill_queues(struct sock *sk);
858 extern void sk_set_memalloc(struct sock *sk);
859 extern void sk_clear_memalloc(struct sock *sk);
860 
861 extern int sk_wait_data(struct sock *sk, long *timeo);
862 
863 struct request_sock_ops;
864 struct timewait_sock_ops;
865 struct inet_hashinfo;
866 struct raw_hashinfo;
867 struct module;
868 
869 /*
870  * caches using SLAB_DESTROY_BY_RCU should let .next pointer from nulls nodes
871  * un-modified. Special care is taken when initializing object to zero.
872  */
873 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
874 {
875         if (offsetof(struct sock, sk_node.next) != 0)
876                 memset(sk, 0, offsetof(struct sock, sk_node.next));
877         memset(&sk->sk_node.pprev, 0,
878                size - offsetof(struct sock, sk_node.pprev));
879 }
880 
881 /* Networking protocol blocks we attach to sockets.
882  * socket layer -> transport layer interface
883  * transport -> network interface is defined by struct inet_proto
884  */
885 struct proto {
886         void                    (*close)(struct sock *sk,
887                                         long timeout);
888         int                     (*connect)(struct sock *sk,
889                                         struct sockaddr *uaddr,
890                                         int addr_len);
891         int                     (*disconnect)(struct sock *sk, int flags);
892 
893         struct sock *           (*accept)(struct sock *sk, int flags, int *err);
894 
895         int                     (*ioctl)(struct sock *sk, int cmd,
896                                          unsigned long arg);
897         int                     (*init)(struct sock *sk);
898         void                    (*destroy)(struct sock *sk);
899         void                    (*shutdown)(struct sock *sk, int how);
900         int                     (*setsockopt)(struct sock *sk, int level,
901                                         int optname, char __user *optval,
902                                         unsigned int optlen);
903         int                     (*getsockopt)(struct sock *sk, int level,
904                                         int optname, char __user *optval,
905                                         int __user *option);
906 #ifdef CONFIG_COMPAT
907         int                     (*compat_setsockopt)(struct sock *sk,
908                                         int level,
909                                         int optname, char __user *optval,
910                                         unsigned int optlen);
911         int                     (*compat_getsockopt)(struct sock *sk,
912                                         int level,
913                                         int optname, char __user *optval,
914                                         int __user *option);
915         int                     (*compat_ioctl)(struct sock *sk,
916                                         unsigned int cmd, unsigned long arg);
917 #endif
918         int                     (*sendmsg)(struct kiocb *iocb, struct sock *sk,
919                                            struct msghdr *msg, size_t len);
920         int                     (*recvmsg)(struct kiocb *iocb, struct sock *sk,
921                                            struct msghdr *msg,
922                                            size_t len, int noblock, int flags,
923                                            int *addr_len);
924         int                     (*sendpage)(struct sock *sk, struct page *page,
925                                         int offset, size_t size, int flags);
926         int                     (*bind)(struct sock *sk,
927                                         struct sockaddr *uaddr, int addr_len);
928 
929         int                     (*backlog_rcv) (struct sock *sk,
930                                                 struct sk_buff *skb);
931 
932         void            (*release_cb)(struct sock *sk);
933         void            (*mtu_reduced)(struct sock *sk);
934 
935         /* Keeping track of sk's, looking them up, and port selection methods. */
936         void                    (*hash)(struct sock *sk);
937         void                    (*unhash)(struct sock *sk);
938         void                    (*rehash)(struct sock *sk);
939         int                     (*get_port)(struct sock *sk, unsigned short snum);
940         void                    (*clear_sk)(struct sock *sk, int size);
941 
942         /* Keeping track of sockets in use */
943 #ifdef CONFIG_PROC_FS
944         unsigned int            inuse_idx;
945 #endif
946 
947         /* Memory pressure */
948         void                    (*enter_memory_pressure)(struct sock *sk);
949         atomic_long_t           *memory_allocated;      /* Current allocated memory. */
950         struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
951         /*
952          * Pressure flag: try to collapse.
953          * Technical note: it is used by multiple contexts non atomically.
954          * All the __sk_mem_schedule() is of this nature: accounting
955          * is strict, actions are advisory and have some latency.
956          */
957         int                     *memory_pressure;
958         long                    *sysctl_mem;
959         int                     *sysctl_wmem;
960         int                     *sysctl_rmem;
961         int                     max_header;
962         bool                    no_autobind;
963 
964         struct kmem_cache       *slab;
965         unsigned int            obj_size;
966         int                     slab_flags;
967 
968         struct percpu_counter   *orphan_count;
969 
970         struct request_sock_ops *rsk_prot;
971         struct timewait_sock_ops *twsk_prot;
972 
973         union {
974                 struct inet_hashinfo    *hashinfo;
975                 struct udp_table        *udp_table;
976                 struct raw_hashinfo     *raw_hash;
977         } h;
978 
979         struct module           *owner;
980 
981         char                    name[32];
982 
983         struct list_head        node;
984 #ifdef SOCK_REFCNT_DEBUG
985         atomic_t                socks;
986 #endif
987 #ifdef CONFIG_MEMCG_KMEM
988         /*
989          * cgroup specific init/deinit functions. Called once for all
990          * protocols that implement it, from cgroups populate function.
991          * This function has to setup any files the protocol want to
992          * appear in the kmem cgroup filesystem.
993          */
994         int                     (*init_cgroup)(struct mem_cgroup *memcg,
995                                                struct cgroup_subsys *ss);
996         void                    (*destroy_cgroup)(struct mem_cgroup *memcg);
997         struct cg_proto         *(*proto_cgroup)(struct mem_cgroup *memcg);
998 #endif
999 };
1000 
1001 /*
1002  * Bits in struct cg_proto.flags
1003  */
1004 enum cg_proto_flags {
1005         /* Currently active and new sockets should be assigned to cgroups */
1006         MEMCG_SOCK_ACTIVE,
1007         /* It was ever activated; we must disarm static keys on destruction */
1008         MEMCG_SOCK_ACTIVATED,
1009 };
1010 
1011 struct cg_proto {
1012         void                    (*enter_memory_pressure)(struct sock *sk);
1013         struct res_counter      *memory_allocated;      /* Current allocated memory. */
1014         struct percpu_counter   *sockets_allocated;     /* Current number of sockets. */
1015         int                     *memory_pressure;
1016         long                    *sysctl_mem;
1017         unsigned long           flags;
1018         /*
1019          * memcg field is used to find which memcg we belong directly
1020          * Each memcg struct can hold more than one cg_proto, so container_of
1021          * won't really cut.
1022          *
1023          * The elegant solution would be having an inverse function to
1024          * proto_cgroup in struct proto, but that means polluting the structure
1025          * for everybody, instead of just for memcg users.
1026          */
1027         struct mem_cgroup       *memcg;
1028 };
1029 
1030 extern int proto_register(struct proto *prot, int alloc_slab);
1031 extern void proto_unregister(struct proto *prot);
1032 
1033 static inline bool memcg_proto_active(struct cg_proto *cg_proto)
1034 {
1035         return test_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
1036 }
1037 
1038 static inline bool memcg_proto_activated(struct cg_proto *cg_proto)
1039 {
1040         return test_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags);
1041 }
1042 
1043 #ifdef SOCK_REFCNT_DEBUG
1044 static inline void sk_refcnt_debug_inc(struct sock *sk)
1045 {
1046         atomic_inc(&sk->sk_prot->socks);
1047 }
1048 
1049 static inline void sk_refcnt_debug_dec(struct sock *sk)
1050 {
1051         atomic_dec(&sk->sk_prot->socks);
1052         printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1053                sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1054 }
1055 
1056 static inline void sk_refcnt_debug_release(const struct sock *sk)
1057 {
1058         if (atomic_read(&sk->sk_refcnt) != 1)
1059                 printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1060                        sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
1061 }
1062 #else /* SOCK_REFCNT_DEBUG */
1063 #define sk_refcnt_debug_inc(sk) do { } while (0)
1064 #define sk_refcnt_debug_dec(sk) do { } while (0)
1065 #define sk_refcnt_debug_release(sk) do { } while (0)
1066 #endif /* SOCK_REFCNT_DEBUG */
1067 
1068 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_NET)
1069 extern struct static_key memcg_socket_limit_enabled;
1070 static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1071                                                struct cg_proto *cg_proto)
1072 {
1073         return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg));
1074 }
1075 #define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled)
1076 #else
1077 #define mem_cgroup_sockets_enabled 0
1078 static inline struct cg_proto *parent_cg_proto(struct proto *proto,
1079                                                struct cg_proto *cg_proto)
1080 {
1081         return NULL;
1082 }
1083 #endif
1084 
1085 
1086 static inline bool sk_has_memory_pressure(const struct sock *sk)
1087 {
1088         return sk->sk_prot->memory_pressure != NULL;
1089 }
1090 
1091 static inline bool sk_under_memory_pressure(const struct sock *sk)
1092 {
1093         if (!sk->sk_prot->memory_pressure)
1094                 return false;
1095 
1096         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1097                 return !!*sk->sk_cgrp->memory_pressure;
1098 
1099         return !!*sk->sk_prot->memory_pressure;
1100 }
1101 
1102 static inline void sk_leave_memory_pressure(struct sock *sk)
1103 {
1104         int *memory_pressure = sk->sk_prot->memory_pressure;
1105 
1106         if (!memory_pressure)
1107                 return;
1108 
1109         if (*memory_pressure)
1110                 *memory_pressure = 0;
1111 
1112         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1113                 struct cg_proto *cg_proto = sk->sk_cgrp;
1114                 struct proto *prot = sk->sk_prot;
1115 
1116                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1117                         if (*cg_proto->memory_pressure)
1118                                 *cg_proto->memory_pressure = 0;
1119         }
1120 
1121 }
1122 
1123 static inline void sk_enter_memory_pressure(struct sock *sk)
1124 {
1125         if (!sk->sk_prot->enter_memory_pressure)
1126                 return;
1127 
1128         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1129                 struct cg_proto *cg_proto = sk->sk_cgrp;
1130                 struct proto *prot = sk->sk_prot;
1131 
1132                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1133                         cg_proto->enter_memory_pressure(sk);
1134         }
1135 
1136         sk->sk_prot->enter_memory_pressure(sk);
1137 }
1138 
1139 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1140 {
1141         long *prot = sk->sk_prot->sysctl_mem;
1142         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1143                 prot = sk->sk_cgrp->sysctl_mem;
1144         return prot[index];
1145 }
1146 
1147 static inline void memcg_memory_allocated_add(struct cg_proto *prot,
1148                                               unsigned long amt,
1149                                               int *parent_status)
1150 {
1151         struct res_counter *fail;
1152         int ret;
1153 
1154         ret = res_counter_charge_nofail(prot->memory_allocated,
1155                                         amt << PAGE_SHIFT, &fail);
1156         if (ret < 0)
1157                 *parent_status = OVER_LIMIT;
1158 }
1159 
1160 static inline void memcg_memory_allocated_sub(struct cg_proto *prot,
1161                                               unsigned long amt)
1162 {
1163         res_counter_uncharge(prot->memory_allocated, amt << PAGE_SHIFT);
1164 }
1165 
1166 static inline u64 memcg_memory_allocated_read(struct cg_proto *prot)
1167 {
1168         u64 ret;
1169         ret = res_counter_read_u64(prot->memory_allocated, RES_USAGE);
1170         return ret >> PAGE_SHIFT;
1171 }
1172 
1173 static inline long
1174 sk_memory_allocated(const struct sock *sk)
1175 {
1176         struct proto *prot = sk->sk_prot;
1177         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1178                 return memcg_memory_allocated_read(sk->sk_cgrp);
1179 
1180         return atomic_long_read(prot->memory_allocated);
1181 }
1182 
1183 static inline long
1184 sk_memory_allocated_add(struct sock *sk, int amt, int *parent_status)
1185 {
1186         struct proto *prot = sk->sk_prot;
1187 
1188         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1189                 memcg_memory_allocated_add(sk->sk_cgrp, amt, parent_status);
1190                 /* update the root cgroup regardless */
1191                 atomic_long_add_return(amt, prot->memory_allocated);
1192                 return memcg_memory_allocated_read(sk->sk_cgrp);
1193         }
1194 
1195         return atomic_long_add_return(amt, prot->memory_allocated);
1196 }
1197 
1198 static inline void
1199 sk_memory_allocated_sub(struct sock *sk, int amt)
1200 {
1201         struct proto *prot = sk->sk_prot;
1202 
1203         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1204                 memcg_memory_allocated_sub(sk->sk_cgrp, amt);
1205 
1206         atomic_long_sub(amt, prot->memory_allocated);
1207 }
1208 
1209 static inline void sk_sockets_allocated_dec(struct sock *sk)
1210 {
1211         struct proto *prot = sk->sk_prot;
1212 
1213         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1214                 struct cg_proto *cg_proto = sk->sk_cgrp;
1215 
1216                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1217                         percpu_counter_dec(cg_proto->sockets_allocated);
1218         }
1219 
1220         percpu_counter_dec(prot->sockets_allocated);
1221 }
1222 
1223 static inline void sk_sockets_allocated_inc(struct sock *sk)
1224 {
1225         struct proto *prot = sk->sk_prot;
1226 
1227         if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
1228                 struct cg_proto *cg_proto = sk->sk_cgrp;
1229 
1230                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
1231                         percpu_counter_inc(cg_proto->sockets_allocated);
1232         }
1233 
1234         percpu_counter_inc(prot->sockets_allocated);
1235 }
1236 
1237 static inline int
1238 sk_sockets_allocated_read_positive(struct sock *sk)
1239 {
1240         struct proto *prot = sk->sk_prot;
1241 
1242         if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
1243                 return percpu_counter_read_positive(sk->sk_cgrp->sockets_allocated);
1244 
1245         return percpu_counter_read_positive(prot->sockets_allocated);
1246 }
1247 
1248 static inline int
1249 proto_sockets_allocated_sum_positive(struct proto *prot)
1250 {
1251         return percpu_counter_sum_positive(prot->sockets_allocated);
1252 }
1253 
1254 static inline long
1255 proto_memory_allocated(struct proto *prot)
1256 {
1257         return atomic_long_read(prot->memory_allocated);
1258 }
1259 
1260 static inline bool
1261 proto_memory_pressure(struct proto *prot)
1262 {
1263         if (!prot->memory_pressure)
1264                 return false;
1265         return !!*prot->memory_pressure;
1266 }
1267 
1268 
1269 #ifdef CONFIG_PROC_FS
1270 /* Called with local bh disabled */
1271 extern void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1272 extern int sock_prot_inuse_get(struct net *net, struct proto *proto);
1273 #else
1274 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1275                 int inc)
1276 {
1277 }
1278 #endif
1279 
1280 
1281 /* With per-bucket locks this operation is not-atomic, so that
1282  * this version is not worse.
1283  */
1284 static inline void __sk_prot_rehash(struct sock *sk)
1285 {
1286         sk->sk_prot->unhash(sk);
1287         sk->sk_prot->hash(sk);
1288 }
1289 
1290 void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
1291 
1292 /* About 10 seconds */
1293 #define SOCK_DESTROY_TIME (10*HZ)
1294 
1295 /* Sockets 0-1023 can't be bound to unless you are superuser */
1296 #define PROT_SOCK       1024
1297 
1298 #define SHUTDOWN_MASK   3
1299 #define RCV_SHUTDOWN    1
1300 #define SEND_SHUTDOWN   2
1301 
1302 #define SOCK_SNDBUF_LOCK        1
1303 #define SOCK_RCVBUF_LOCK        2
1304 #define SOCK_BINDADDR_LOCK      4
1305 #define SOCK_BINDPORT_LOCK      8
1306 
1307 /* sock_iocb: used to kick off async processing of socket ios */
1308 struct sock_iocb {
1309         struct list_head        list;
1310 
1311         int                     flags;
1312         int                     size;
1313         struct socket           *sock;
1314         struct sock             *sk;
1315         struct scm_cookie       *scm;
1316         struct msghdr           *msg, async_msg;
1317         struct kiocb            *kiocb;
1318 };
1319 
1320 static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
1321 {
1322         return (struct sock_iocb *)iocb->private;
1323 }
1324 
1325 static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
1326 {
1327         return si->kiocb;
1328 }
1329 
1330 struct socket_alloc {
1331         struct socket socket;
1332         struct inode vfs_inode;
1333 };
1334 
1335 static inline struct socket *SOCKET_I(struct inode *inode)
1336 {
1337         return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1338 }
1339 
1340 static inline struct inode *SOCK_INODE(struct socket *socket)
1341 {
1342         return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1343 }
1344 
1345 /*
1346  * Functions for memory accounting
1347  */
1348 extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
1349 extern void __sk_mem_reclaim(struct sock *sk);
1350 
1351 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
1352 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1353 #define SK_MEM_SEND     0
1354 #define SK_MEM_RECV     1
1355 
1356 static inline int sk_mem_pages(int amt)
1357 {
1358         return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1359 }
1360 
1361 static inline bool sk_has_account(struct sock *sk)
1362 {
1363         /* return true if protocol supports memory accounting */
1364         return !!sk->sk_prot->memory_allocated;
1365 }
1366 
1367 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1368 {
1369         if (!sk_has_account(sk))
1370                 return true;
1371         return size <= sk->sk_forward_alloc ||
1372                 __sk_mem_schedule(sk, size, SK_MEM_SEND);
1373 }
1374 
1375 static inline bool
1376 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1377 {
1378         if (!sk_has_account(sk))
1379                 return true;
1380         return size<= sk->sk_forward_alloc ||
1381                 __sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1382                 skb_pfmemalloc(skb);
1383 }
1384 
1385 static inline void sk_mem_reclaim(struct sock *sk)
1386 {
1387         if (!sk_has_account(sk))
1388                 return;
1389         if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1390                 __sk_mem_reclaim(sk);
1391 }
1392 
1393 static inline void sk_mem_reclaim_partial(struct sock *sk)
1394 {
1395         if (!sk_has_account(sk))
1396                 return;
1397         if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1398                 __sk_mem_reclaim(sk);
1399 }
1400 
1401 static inline void sk_mem_charge(struct sock *sk, int size)
1402 {
1403         if (!sk_has_account(sk))
1404                 return;
1405         sk->sk_forward_alloc -= size;
1406 }
1407 
1408 static inline void sk_mem_uncharge(struct sock *sk, int size)
1409 {
1410         if (!sk_has_account(sk))
1411                 return;
1412         sk->sk_forward_alloc += size;
1413 }
1414 
1415 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1416 {
1417         sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
1418         sk->sk_wmem_queued -= skb->truesize;
1419         sk_mem_uncharge(sk, skb->truesize);
1420         __kfree_skb(skb);
1421 }
1422 
1423 /* Used by processes to "lock" a socket state, so that
1424  * interrupts and bottom half handlers won't change it
1425  * from under us. It essentially blocks any incoming
1426  * packets, so that we won't get any new data or any
1427  * packets that change the state of the socket.
1428  *
1429  * While locked, BH processing will add new packets to
1430  * the backlog queue.  This queue is processed by the
1431  * owner of the socket lock right before it is released.
1432  *
1433  * Since ~2.3.5 it is also exclusive sleep lock serializing
1434  * accesses from user process context.
1435  */
1436 #define sock_owned_by_user(sk)  ((sk)->sk_lock.owned)
1437 
1438 /*
1439  * Macro so as to not evaluate some arguments when
1440  * lockdep is not enabled.
1441  *
1442  * Mark both the sk_lock and the sk_lock.slock as a
1443  * per-address-family lock class.
1444  */
1445 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)       \
1446 do {                                                                    \
1447         sk->sk_lock.owned = 0;                                          \
1448         init_waitqueue_head(&sk->sk_lock.wq);                           \
1449         spin_lock_init(&(sk)->sk_lock.slock);                           \
1450         debug_check_no_locks_freed((void *)&(sk)->sk_lock,              \
1451                         sizeof((sk)->sk_lock));                         \
1452         lockdep_set_class_and_name(&(sk)->sk_lock.slock,                \
1453                                 (skey), (sname));                               \
1454         lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);     \
1455 } while (0)
1456 
1457 extern void lock_sock_nested(struct sock *sk, int subclass);
1458 
1459 static inline void lock_sock(struct sock *sk)
1460 {
1461         lock_sock_nested(sk, 0);
1462 }
1463 
1464 extern void release_sock(struct sock *sk);
1465 
1466 /* BH context may only use the following locking interface. */
1467 #define bh_lock_sock(__sk)      spin_lock(&((__sk)->sk_lock.slock))
1468 #define bh_lock_sock_nested(__sk) \
1469                                 spin_lock_nested(&((__sk)->sk_lock.slock), \
1470                                 SINGLE_DEPTH_NESTING)
1471 #define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->sk_lock.slock))
1472 
1473 extern bool lock_sock_fast(struct sock *sk);
1474 /**
1475  * unlock_sock_fast - complement of lock_sock_fast
1476  * @sk: socket
1477  * @slow: slow mode
1478  *
1479  * fast unlock socket for user context.
1480  * If slow mode is on, we call regular release_sock()
1481  */
1482 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1483 {
1484         if (slow)
1485                 release_sock(sk);
1486         else
1487                 spin_unlock_bh(&sk->sk_lock.slock);
1488 }
1489 
1490 
1491 extern struct sock              *sk_alloc(struct net *net, int family,
1492                                           gfp_t priority,
1493                                           struct proto *prot);
1494 extern void                     sk_free(struct sock *sk);
1495 extern void                     sk_release_kernel(struct sock *sk);
1496 extern struct sock              *sk_clone_lock(const struct sock *sk,
1497                                                const gfp_t priority);
1498 
1499 extern struct sk_buff           *sock_wmalloc(struct sock *sk,
1500                                               unsigned long size, int force,
1501                                               gfp_t priority);
1502 extern struct sk_buff           *sock_rmalloc(struct sock *sk,
1503                                               unsigned long size, int force,
1504                                               gfp_t priority);
1505 extern void                     sock_wfree(struct sk_buff *skb);
1506 extern void                     sock_rfree(struct sk_buff *skb);
1507 extern void                     sock_edemux(struct sk_buff *skb);
1508 
1509 extern int                      sock_setsockopt(struct socket *sock, int level,
1510                                                 int op, char __user *optval,
1511                                                 unsigned int optlen);
1512 
1513 extern int                      sock_getsockopt(struct socket *sock, int level,
1514                                                 int op, char __user *optval,
1515                                                 int __user *optlen);
1516 extern struct sk_buff           *sock_alloc_send_skb(struct sock *sk,
1517                                                      unsigned long size,
1518                                                      int noblock,
1519                                                      int *errcode);
1520 extern struct sk_buff           *sock_alloc_send_pskb(struct sock *sk,
1521                                                       unsigned long header_len,
1522                                                       unsigned long data_len,
1523                                                       int noblock,
1524                                                       int *errcode);
1525 extern void *sock_kmalloc(struct sock *sk, int size,
1526                           gfp_t priority);
1527 extern void sock_kfree_s(struct sock *sk, void *mem, int size);
1528 extern void sk_send_sigurg(struct sock *sk);
1529 
1530 /*
1531  * Functions to fill in entries in struct proto_ops when a protocol
1532  * does not implement a particular function.
1533  */
1534 extern int                      sock_no_bind(struct socket *,
1535                                              struct sockaddr *, int);
1536 extern int                      sock_no_connect(struct socket *,
1537                                                 struct sockaddr *, int, int);
1538 extern int                      sock_no_socketpair(struct socket *,
1539                                                    struct socket *);
1540 extern int                      sock_no_accept(struct socket *,
1541                                                struct socket *, int);
1542 extern int                      sock_no_getname(struct socket *,
1543                                                 struct sockaddr *, int *, int);
1544 extern unsigned int             sock_no_poll(struct file *, struct socket *,
1545                                              struct poll_table_struct *);
1546 extern int                      sock_no_ioctl(struct socket *, unsigned int,
1547                                               unsigned long);
1548 extern int                      sock_no_listen(struct socket *, int);
1549 extern int                      sock_no_shutdown(struct socket *, int);
1550 extern int                      sock_no_getsockopt(struct socket *, int , int,
1551                                                    char __user *, int __user *);
1552 extern int                      sock_no_setsockopt(struct socket *, int, int,
1553                                                    char __user *, unsigned int);
1554 extern int                      sock_no_sendmsg(struct kiocb *, struct socket *,
1555                                                 struct msghdr *, size_t);
1556 extern int                      sock_no_recvmsg(struct kiocb *, struct socket *,
1557                                                 struct msghdr *, size_t, int);
1558 extern int                      sock_no_mmap(struct file *file,
1559                                              struct socket *sock,
1560                                              struct vm_area_struct *vma);
1561 extern ssize_t                  sock_no_sendpage(struct socket *sock,
1562                                                 struct page *page,
1563                                                 int offset, size_t size,
1564                                                 int flags);
1565 
1566 /*
1567  * Functions to fill in entries in struct proto_ops when a protocol
1568  * uses the inet style.
1569  */
1570 extern int sock_common_getsockopt(struct socket *sock, int level, int optname,
1571                                   char __user *optval, int __user *optlen);
1572 extern int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
1573                                struct msghdr *msg, size_t size, int flags);
1574 extern int sock_common_setsockopt(struct socket *sock, int level, int optname,
1575                                   char __user *optval, unsigned int optlen);
1576 extern int compat_sock_common_getsockopt(struct socket *sock, int level,
1577                 int optname, char __user *optval, int __user *optlen);
1578 extern int compat_sock_common_setsockopt(struct socket *sock, int level,
1579                 int optname, char __user *optval, unsigned int optlen);
1580 
1581 extern void sk_common_release(struct sock *sk);
1582 
1583 /*
1584  *      Default socket callbacks and setup code
1585  */
1586 
1587 /* Initialise core socket variables */
1588 extern void sock_init_data(struct socket *sock, struct sock *sk);
1589 
1590 extern void sk_filter_release_rcu(struct rcu_head *rcu);
1591 
1592 /**
1593  *      sk_filter_release - release a socket filter
1594  *      @fp: filter to remove
1595  *
1596  *      Remove a filter from a socket and release its resources.
1597  */
1598 
1599 static inline void sk_filter_release(struct sk_filter *fp)
1600 {
1601         if (atomic_dec_and_test(&fp->refcnt))
1602                 call_rcu(&fp->rcu, sk_filter_release_rcu);
1603 }
1604 
1605 static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
1606 {
1607         unsigned int size = sk_filter_len(fp);
1608 
1609         atomic_sub(size, &sk->sk_omem_alloc);
1610         sk_filter_release(fp);
1611 }
1612 
1613 static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
1614 {
1615         atomic_inc(&fp->refcnt);
1616         atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
1617 }
1618 
1619 /*
1620  * Socket reference counting postulates.
1621  *
1622  * * Each user of socket SHOULD hold a reference count.
1623  * * Each access point to socket (an hash table bucket, reference from a list,
1624  *   running timer, skb in flight MUST hold a reference count.
1625  * * When reference count hits 0, it means it will never increase back.
1626  * * When reference count hits 0, it means that no references from
1627  *   outside exist to this socket and current process on current CPU
1628  *   is last user and may/should destroy this socket.
1629  * * sk_free is called from any context: process, BH, IRQ. When
1630  *   it is called, socket has no references from outside -> sk_free
1631  *   may release descendant resources allocated by the socket, but
1632  *   to the time when it is called, socket is NOT referenced by any
1633  *   hash tables, lists etc.
1634  * * Packets, delivered from outside (from network or from another process)
1635  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1636  *   when they sit in queue. Otherwise, packets will leak to hole, when
1637  *   socket is looked up by one cpu and unhasing is made by another CPU.
1638  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1639  *   (leak to backlog). Packet socket does all the processing inside
1640  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1641  *   use separate SMP lock, so that they are prone too.
1642  */
1643 
1644 /* Ungrab socket and destroy it, if it was the last reference. */
1645 static inline void sock_put(struct sock *sk)
1646 {
1647         if (atomic_dec_and_test(&sk->sk_refcnt))
1648                 sk_free(sk);
1649 }
1650 
1651 extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1652                           const int nested);
1653 
1654 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1655 {
1656         sk->sk_tx_queue_mapping = tx_queue;
1657 }
1658 
1659 static inline void sk_tx_queue_clear(struct sock *sk)
1660 {
1661         sk->sk_tx_queue_mapping = -1;
1662 }
1663 
1664 static inline int sk_tx_queue_get(const struct sock *sk)
1665 {
1666         return sk ? sk->sk_tx_queue_mapping : -1;
1667 }
1668 
1669 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1670 {
1671         sk_tx_queue_clear(sk);
1672         sk->sk_socket = sock;
1673 }
1674 
1675 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1676 {
1677         BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1678         return &rcu_dereference_raw(sk->sk_wq)->wait;
1679 }
1680 /* Detach socket from process context.
1681  * Announce socket dead, detach it from wait queue and inode.
1682  * Note that parent inode held reference count on this struct sock,
1683  * we do not release it in this function, because protocol
1684  * probably wants some additional cleanups or even continuing
1685  * to work with this socket (TCP).
1686  */
1687 static inline void sock_orphan(struct sock *sk)
1688 {
1689         write_lock_bh(&sk->sk_callback_lock);
1690         sock_set_flag(sk, SOCK_DEAD);
1691         sk_set_socket(sk, NULL);
1692         sk->sk_wq  = NULL;
1693         write_unlock_bh(&sk->sk_callback_lock);
1694 }
1695 
1696 static inline void sock_graft(struct sock *sk, struct socket *parent)
1697 {
1698         write_lock_bh(&sk->sk_callback_lock);
1699         sk->sk_wq = parent->wq;
1700         parent->sk = sk;
1701         sk_set_socket(sk, parent);
1702         security_sock_graft(sk, parent);
1703         write_unlock_bh(&sk->sk_callback_lock);
1704 }
1705 
1706 extern kuid_t sock_i_uid(struct sock *sk);
1707 extern unsigned long sock_i_ino(struct sock *sk);
1708 
1709 static inline struct dst_entry *
1710 __sk_dst_get(struct sock *sk)
1711 {
1712         return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
1713                                                        lockdep_is_held(&sk->sk_lock.slock));
1714 }
1715 
1716 static inline struct dst_entry *
1717 sk_dst_get(struct sock *sk)
1718 {
1719         struct dst_entry *dst;
1720 
1721         rcu_read_lock();
1722         dst = rcu_dereference(sk->sk_dst_cache);
1723         if (dst)
1724                 dst_hold(dst);
1725         rcu_read_unlock();
1726         return dst;
1727 }
1728 
1729 extern void sk_reset_txq(struct sock *sk);
1730 
1731 static inline void dst_negative_advice(struct sock *sk)
1732 {
1733         struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1734 
1735         if (dst && dst->ops->negative_advice) {
1736                 ndst = dst->ops->negative_advice(dst);
1737 
1738                 if (ndst != dst) {
1739                         rcu_assign_pointer(sk->sk_dst_cache, ndst);
1740                         sk_reset_txq(sk);
1741                 }
1742         }
1743 }
1744 
1745 static inline void
1746 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1747 {
1748         struct dst_entry *old_dst;
1749 
1750         sk_tx_queue_clear(sk);
1751         /*
1752          * This can be called while sk is owned by the caller only,
1753          * with no state that can be checked in a rcu_dereference_check() cond
1754          */
1755         old_dst = rcu_dereference_raw(sk->sk_dst_cache);
1756         rcu_assign_pointer(sk->sk_dst_cache, dst);
1757         dst_release(old_dst);
1758 }
1759 
1760 static inline void
1761 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1762 {
1763         spin_lock(&sk->sk_dst_lock);
1764         __sk_dst_set(sk, dst);
1765         spin_unlock(&sk->sk_dst_lock);
1766 }
1767 
1768 static inline void
1769 __sk_dst_reset(struct sock *sk)
1770 {
1771         __sk_dst_set(sk, NULL);
1772 }
1773 
1774 static inline void
1775 sk_dst_reset(struct sock *sk)
1776 {
1777         spin_lock(&sk->sk_dst_lock);
1778         __sk_dst_reset(sk);
1779         spin_unlock(&sk->sk_dst_lock);
1780 }
1781 
1782 extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1783 
1784 extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1785 
1786 static inline bool sk_can_gso(const struct sock *sk)
1787 {
1788         return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1789 }
1790 
1791 extern void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1792 
1793 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
1794 {
1795         sk->sk_route_nocaps |= flags;
1796         sk->sk_route_caps &= ~flags;
1797 }
1798 
1799 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
1800                                            char __user *from, char *to,
1801                                            int copy, int offset)
1802 {
1803         if (skb->ip_summed == CHECKSUM_NONE) {
1804                 int err = 0;
1805                 __wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
1806                 if (err)
1807                         return err;
1808                 skb->csum = csum_block_add(skb->csum, csum, offset);
1809         } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1810                 if (!access_ok(VERIFY_READ, from, copy) ||
1811                     __copy_from_user_nocache(to, from, copy))
1812                         return -EFAULT;
1813         } else if (copy_from_user(to, from, copy))
1814                 return -EFAULT;
1815 
1816         return 0;
1817 }
1818 
1819 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
1820                                        char __user *from, int copy)
1821 {
1822         int err, offset = skb->len;
1823 
1824         err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
1825                                        copy, offset);
1826         if (err)
1827                 __skb_trim(skb, offset);
1828 
1829         return err;
1830 }
1831 
1832 static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
1833                                            struct sk_buff *skb,
1834                                            struct page *page,
1835                                            int off, int copy)
1836 {
1837         int err;
1838 
1839         err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
1840                                        copy, skb->len);
1841         if (err)
1842                 return err;
1843 
1844         skb->len             += copy;
1845         skb->data_len        += copy;
1846         skb->truesize        += copy;
1847         sk->sk_wmem_queued   += copy;
1848         sk_mem_charge(sk, copy);
1849         return 0;
1850 }
1851 
1852 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
1853                                    struct sk_buff *skb, struct page *page,
1854                                    int off, int copy)
1855 {
1856         if (skb->ip_summed == CHECKSUM_NONE) {
1857                 int err = 0;
1858                 __wsum csum = csum_and_copy_from_user(from,
1859                                                      page_address(page) + off,
1860                                                             copy, 0, &err);
1861                 if (err)
1862                         return err;
1863                 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1864         } else if (copy_from_user(page_address(page) + off, from, copy))
1865                 return -EFAULT;
1866 
1867         skb->len             += copy;
1868         skb->data_len        += copy;
1869         skb->truesize        += copy;
1870         sk->sk_wmem_queued   += copy;
1871         sk_mem_charge(sk, copy);
1872         return 0;
1873 }
1874 
1875 /**
1876  * sk_wmem_alloc_get - returns write allocations
1877  * @sk: socket
1878  *
1879  * Returns sk_wmem_alloc minus initial offset of one
1880  */
1881 static inline int sk_wmem_alloc_get(const struct sock *sk)
1882 {
1883         return atomic_read(&sk->sk_wmem_alloc) - 1;
1884 }
1885 
1886 /**
1887  * sk_rmem_alloc_get - returns read allocations
1888  * @sk: socket
1889  *
1890  * Returns sk_rmem_alloc
1891  */
1892 static inline int sk_rmem_alloc_get(const struct sock *sk)
1893 {
1894         return atomic_read(&sk->sk_rmem_alloc);
1895 }
1896 
1897 /**
1898  * sk_has_allocations - check if allocations are outstanding
1899  * @sk: socket
1900  *
1901  * Returns true if socket has write or read allocations
1902  */
1903 static inline bool sk_has_allocations(const struct sock *sk)
1904 {
1905         return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1906 }
1907 
1908 /**
1909  * wq_has_sleeper - check if there are any waiting processes
1910  * @wq: struct socket_wq
1911  *
1912  * Returns true if socket_wq has waiting processes
1913  *
1914  * The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
1915  * barrier call. They were added due to the race found within the tcp code.
1916  *
1917  * Consider following tcp code paths:
1918  *
1919  * CPU1                  CPU2
1920  *
1921  * sys_select            receive packet
1922  *   ...                 ...
1923  *   __add_wait_queue    update tp->rcv_nxt
1924  *   ...                 ...
1925  *   tp->rcv_nxt check   sock_def_readable
1926  *   ...                 {
1927  *   schedule               rcu_read_lock();
1928  *                          wq = rcu_dereference(sk->sk_wq);
1929  *                          if (wq && waitqueue_active(&wq->wait))
1930  *                              wake_up_interruptible(&wq->wait)
1931  *                          ...
1932  *                       }
1933  *
1934  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1935  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1936  * could then endup calling schedule and sleep forever if there are no more
1937  * data on the socket.
1938  *
1939  */
1940 static inline bool wq_has_sleeper(struct socket_wq *wq)
1941 {
1942         /* We need to be sure we are in sync with the
1943          * add_wait_queue modifications to the wait queue.
1944          *
1945          * This memory barrier is paired in the sock_poll_wait.
1946          */
1947         smp_mb();
1948         return wq && waitqueue_active(&wq->wait);
1949 }
1950 
1951 /**
1952  * sock_poll_wait - place memory barrier behind the poll_wait call.
1953  * @filp:           file
1954  * @wait_address:   socket wait queue
1955  * @p:              poll_table
1956  *
1957  * See the comments in the wq_has_sleeper function.
1958  */
1959 static inline void sock_poll_wait(struct file *filp,
1960                 wait_queue_head_t *wait_address, poll_table *p)
1961 {
1962         if (!poll_does_not_wait(p) && wait_address) {
1963                 poll_wait(filp, wait_address, p);
1964                 /* We need to be sure we are in sync with the
1965                  * socket flags modification.
1966                  *
1967                  * This memory barrier is paired in the wq_has_sleeper.
1968                  */
1969                 smp_mb();
1970         }
1971 }
1972 
1973 /*
1974  *      Queue a received datagram if it will fit. Stream and sequenced
1975  *      protocols can't normally use this as they need to fit buffers in
1976  *      and play with them.
1977  *
1978  *      Inlined as it's very short and called for pretty much every
1979  *      packet ever received.
1980  */
1981 
1982 static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1983 {
1984         skb_orphan(skb);
1985         skb->sk = sk;
1986         skb->destructor = sock_wfree;
1987         /*
1988          * We used to take a refcount on sk, but following operation
1989          * is enough to guarantee sk_free() wont free this sock until
1990          * all in-flight packets are completed
1991          */
1992         atomic_add(skb->truesize, &sk->sk_wmem_alloc);
1993 }
1994 
1995 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
1996 {
1997         skb_orphan(skb);
1998         skb->sk = sk;
1999         skb->destructor = sock_rfree;
2000         atomic_add(skb->truesize, &sk->sk_rmem_alloc);
2001         sk_mem_charge(sk, skb->truesize);
2002 }
2003 
2004 extern void sk_reset_timer(struct sock *sk, struct timer_list *timer,
2005                            unsigned long expires);
2006 
2007 extern void sk_stop_timer(struct sock *sk, struct timer_list *timer);
2008 
2009 extern int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2010 
2011 extern int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
2012 
2013 /*
2014  *      Recover an error report and clear atomically
2015  */
2016 
2017 static inline int sock_error(struct sock *sk)
2018 {
2019         int err;
2020         if (likely(!sk->sk_err))
2021                 return 0;
2022         err = xchg(&sk->sk_err, 0);
2023         return -err;
2024 }
2025 
2026 static inline unsigned long sock_wspace(struct sock *sk)
2027 {
2028         int amt = 0;
2029 
2030         if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
2031                 amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
2032                 if (amt < 0)
2033                         amt = 0;
2034         }
2035         return amt;
2036 }
2037 
2038 static inline void sk_wake_async(struct sock *sk, int how, int band)
2039 {
2040         if (sock_flag(sk, SOCK_FASYNC))
2041                 sock_wake_async(sk->sk_socket, how, band);
2042 }
2043 
2044 #define SOCK_MIN_SNDBUF 2048
2045 /*
2046  * Since sk_rmem_alloc sums skb->truesize, even a small frame might need
2047  * sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak
2048  */
2049 #define SOCK_MIN_RCVBUF (2048 + sizeof(struct sk_buff))
2050 
2051 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2052 {
2053         if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
2054                 sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2055                 sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
2056         }
2057 }
2058 
2059 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp);
2060 
2061 /**
2062  * sk_page_frag - return an appropriate page_frag
2063  * @sk: socket
2064  *
2065  * If socket allocation mode allows current thread to sleep, it means its
2066  * safe to use the per task page_frag instead of the per socket one.
2067  */
2068 static inline struct page_frag *sk_page_frag(struct sock *sk)
2069 {
2070         if (sk->sk_allocation & __GFP_WAIT)
2071                 return &current->task_frag;
2072 
2073         return &sk->sk_frag;
2074 }
2075 
2076 extern bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2077 
2078 /*
2079  *      Default write policy as shown to user space via poll/select/SIGIO
2080  */
2081 static inline bool sock_writeable(const struct sock *sk)
2082 {
2083         return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
2084 }
2085 
2086 static inline gfp_t gfp_any(void)
2087 {
2088         return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2089 }
2090 
2091 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2092 {
2093         return noblock ? 0 : sk->sk_rcvtimeo;
2094 }
2095 
2096 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2097 {
2098         return noblock ? 0 : sk->sk_sndtimeo;
2099 }
2100 
2101 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2102 {
2103         return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
2104 }
2105 
2106 /* Alas, with timeout socket operations are not restartable.
2107  * Compare this to poll().
2108  */
2109 static inline int sock_intr_errno(long timeo)
2110 {
2111         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2112 }
2113 
2114 extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2115         struct sk_buff *skb);
2116 extern void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2117         struct sk_buff *skb);
2118 
2119 static inline void
2120 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2121 {
2122         ktime_t kt = skb->tstamp;
2123         struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2124 
2125         /*
2126          * generate control messages if
2127          * - receive time stamping in software requested (SOCK_RCVTSTAMP
2128          *   or SOCK_TIMESTAMPING_RX_SOFTWARE)
2129          * - software time stamp available and wanted
2130          *   (SOCK_TIMESTAMPING_SOFTWARE)
2131          * - hardware time stamps available and wanted
2132          *   (SOCK_TIMESTAMPING_SYS_HARDWARE or
2133          *   SOCK_TIMESTAMPING_RAW_HARDWARE)
2134          */
2135         if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2136             sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||
2137             (kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||
2138             (hwtstamps->hwtstamp.tv64 &&
2139              sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)) ||
2140             (hwtstamps->syststamp.tv64 &&
2141              sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE)))
2142                 __sock_recv_timestamp(msg, sk, skb);
2143         else
2144                 sk->sk_stamp = kt;
2145 
2146         if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2147                 __sock_recv_wifi_status(msg, sk, skb);
2148 }
2149 
2150 extern void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2151                                      struct sk_buff *skb);
2152 
2153 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2154                                           struct sk_buff *skb)
2155 {
2156 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)                       | \
2157                            (1UL << SOCK_RCVTSTAMP)                      | \
2158                            (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE)       | \
2159                            (1UL << SOCK_TIMESTAMPING_SOFTWARE)          | \
2160                            (1UL << SOCK_TIMESTAMPING_RAW_HARDWARE)      | \
2161                            (1UL << SOCK_TIMESTAMPING_SYS_HARDWARE))
2162 
2163         if (sk->sk_flags & FLAGS_TS_OR_DROPS)
2164                 __sock_recv_ts_and_drops(msg, sk, skb);
2165         else
2166                 sk->sk_stamp = skb->tstamp;
2167 }
2168 
2169 /**
2170  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2171  * @sk:         socket sending this packet
2172  * @tx_flags:   filled with instructions for time stamping
2173  *
2174  * Currently only depends on SOCK_TIMESTAMPING* flags.
2175  */
2176 extern void sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
2177 
2178 /**
2179  * sk_eat_skb - Release a skb if it is no longer needed
2180  * @sk: socket to eat this skb from
2181  * @skb: socket buffer to eat
2182  * @copied_early: flag indicating whether DMA operations copied this data early
2183  *
2184  * This routine must be called with interrupts disabled or with the socket
2185  * locked so that the sk_buff queue operation is ok.
2186 */
2187 #ifdef CONFIG_NET_DMA
2188 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, bool copied_early)
2189 {
2190         __skb_unlink(skb, &sk->sk_receive_queue);
2191         if (!copied_early)
2192                 __kfree_skb(skb);
2193         else
2194                 __skb_queue_tail(&sk->sk_async_wait_queue, skb);
2195 }
2196 #else
2197 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, bool copied_early)
2198 {
2199         __skb_unlink(skb, &sk->sk_receive_queue);
2200         __kfree_skb(skb);
2201 }
2202 #endif
2203 
2204 static inline
2205 struct net *sock_net(const struct sock *sk)
2206 {
2207         return read_pnet(&sk->sk_net);
2208 }
2209 
2210 static inline
2211 void sock_net_set(struct sock *sk, struct net *net)
2212 {
2213         write_pnet(&sk->sk_net, net);
2214 }
2215 
2216 /*
2217  * Kernel sockets, f.e. rtnl or icmp_socket, are a part of a namespace.
2218  * They should not hold a reference to a namespace in order to allow
2219  * to stop it.
2220  * Sockets after sk_change_net should be released using sk_release_kernel
2221  */
2222 static inline void sk_change_net(struct sock *sk, struct net *net)
2223 {
2224         put_net(sock_net(sk));
2225         sock_net_set(sk, hold_net(net));
2226 }
2227 
2228 static inline struct sock *skb_steal_sock(struct sk_buff *skb)
2229 {
2230         if (skb->sk) {
2231                 struct sock *sk = skb->sk;
2232 
2233                 skb->destructor = NULL;
2234                 skb->sk = NULL;
2235                 return sk;
2236         }
2237         return NULL;
2238 }
2239 
2240 extern void sock_enable_timestamp(struct sock *sk, int flag);
2241 extern int sock_get_timestamp(struct sock *, struct timeval __user *);
2242 extern int sock_get_timestampns(struct sock *, struct timespec __user *);
2243 
2244 /*
2245  *      Enable debug/info messages
2246  */
2247 extern int net_msg_warn;
2248 #define NETDEBUG(fmt, args...) \
2249         do { if (net_msg_warn) printk(fmt,##args); } while (0)
2250 
2251 #define LIMIT_NETDEBUG(fmt, args...) \
2252         do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
2253 
2254 extern __u32 sysctl_wmem_max;
2255 extern __u32 sysctl_rmem_max;
2256 
2257 extern int sysctl_optmem_max;
2258 
2259 extern __u32 sysctl_wmem_default;
2260 extern __u32 sysctl_rmem_default;
2261 
2262 #endif  /* _SOCK_H */
2263 

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