Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/net/ppp/ppp_generic.c

  1 /*
  2  * Generic PPP layer for Linux.
  3  *
  4  * Copyright 1999-2002 Paul Mackerras.
  5  *
  6  *  This program is free software; you can redistribute it and/or
  7  *  modify it under the terms of the GNU General Public License
  8  *  as published by the Free Software Foundation; either version
  9  *  2 of the License, or (at your option) any later version.
 10  *
 11  * The generic PPP layer handles the PPP network interfaces, the
 12  * /dev/ppp device, packet and VJ compression, and multilink.
 13  * It talks to PPP `channels' via the interface defined in
 14  * include/linux/ppp_channel.h.  Channels provide the basic means for
 15  * sending and receiving PPP frames on some kind of communications
 16  * channel.
 17  *
 18  * Part of the code in this driver was inspired by the old async-only
 19  * PPP driver, written by Michael Callahan and Al Longyear, and
 20  * subsequently hacked by Paul Mackerras.
 21  *
 22  * ==FILEVERSION 20041108==
 23  */
 24 
 25 #include <linux/module.h>
 26 #include <linux/kernel.h>
 27 #include <linux/kmod.h>
 28 #include <linux/init.h>
 29 #include <linux/list.h>
 30 #include <linux/idr.h>
 31 #include <linux/netdevice.h>
 32 #include <linux/poll.h>
 33 #include <linux/ppp_defs.h>
 34 #include <linux/filter.h>
 35 #include <linux/ppp-ioctl.h>
 36 #include <linux/ppp_channel.h>
 37 #include <linux/ppp-comp.h>
 38 #include <linux/skbuff.h>
 39 #include <linux/rtnetlink.h>
 40 #include <linux/if_arp.h>
 41 #include <linux/ip.h>
 42 #include <linux/tcp.h>
 43 #include <linux/spinlock.h>
 44 #include <linux/rwsem.h>
 45 #include <linux/stddef.h>
 46 #include <linux/device.h>
 47 #include <linux/mutex.h>
 48 #include <linux/slab.h>
 49 #include <linux/file.h>
 50 #include <asm/unaligned.h>
 51 #include <net/slhc_vj.h>
 52 #include <linux/atomic.h>
 53 
 54 #include <linux/nsproxy.h>
 55 #include <net/net_namespace.h>
 56 #include <net/netns/generic.h>
 57 
 58 #define PPP_VERSION     "2.4.2"
 59 
 60 /*
 61  * Network protocols we support.
 62  */
 63 #define NP_IP   0               /* Internet Protocol V4 */
 64 #define NP_IPV6 1               /* Internet Protocol V6 */
 65 #define NP_IPX  2               /* IPX protocol */
 66 #define NP_AT   3               /* Appletalk protocol */
 67 #define NP_MPLS_UC 4            /* MPLS unicast */
 68 #define NP_MPLS_MC 5            /* MPLS multicast */
 69 #define NUM_NP  6               /* Number of NPs. */
 70 
 71 #define MPHDRLEN        6       /* multilink protocol header length */
 72 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
 73 
 74 /*
 75  * An instance of /dev/ppp can be associated with either a ppp
 76  * interface unit or a ppp channel.  In both cases, file->private_data
 77  * points to one of these.
 78  */
 79 struct ppp_file {
 80         enum {
 81                 INTERFACE=1, CHANNEL
 82         }               kind;
 83         struct sk_buff_head xq;         /* pppd transmit queue */
 84         struct sk_buff_head rq;         /* receive queue for pppd */
 85         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
 86         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
 87         int             hdrlen;         /* space to leave for headers */
 88         int             index;          /* interface unit / channel number */
 89         int             dead;           /* unit/channel has been shut down */
 90 };
 91 
 92 #define PF_TO_X(pf, X)          container_of(pf, X, file)
 93 
 94 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
 95 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
 96 
 97 /*
 98  * Data structure to hold primary network stats for which
 99  * we want to use 64 bit storage.  Other network stats
100  * are stored in dev->stats of the ppp strucute.
101  */
102 struct ppp_link_stats {
103         u64 rx_packets;
104         u64 tx_packets;
105         u64 rx_bytes;
106         u64 tx_bytes;
107 };
108 
109 /*
110  * Data structure describing one ppp unit.
111  * A ppp unit corresponds to a ppp network interface device
112  * and represents a multilink bundle.
113  * It can have 0 or more ppp channels connected to it.
114  */
115 struct ppp {
116         struct ppp_file file;           /* stuff for read/write/poll 0 */
117         struct file     *owner;         /* file that owns this unit 48 */
118         struct list_head channels;      /* list of attached channels 4c */
119         int             n_channels;     /* how many channels are attached 54 */
120         spinlock_t      rlock;          /* lock for receive side 58 */
121         spinlock_t      wlock;          /* lock for transmit side 5c */
122         int             mru;            /* max receive unit 60 */
123         unsigned int    flags;          /* control bits 64 */
124         unsigned int    xstate;         /* transmit state bits 68 */
125         unsigned int    rstate;         /* receive state bits 6c */
126         int             debug;          /* debug flags 70 */
127         struct slcompress *vj;          /* state for VJ header compression */
128         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
129         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
130         struct compressor *xcomp;       /* transmit packet compressor 8c */
131         void            *xc_state;      /* its internal state 90 */
132         struct compressor *rcomp;       /* receive decompressor 94 */
133         void            *rc_state;      /* its internal state 98 */
134         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
135         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
136         struct net_device *dev;         /* network interface device a4 */
137         int             closing;        /* is device closing down? a8 */
138 #ifdef CONFIG_PPP_MULTILINK
139         int             nxchan;         /* next channel to send something on */
140         u32             nxseq;          /* next sequence number to send */
141         int             mrru;           /* MP: max reconst. receive unit */
142         u32             nextseq;        /* MP: seq no of next packet */
143         u32             minseq;         /* MP: min of most recent seqnos */
144         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
145 #endif /* CONFIG_PPP_MULTILINK */
146 #ifdef CONFIG_PPP_FILTER
147         struct bpf_prog *pass_filter;   /* filter for packets to pass */
148         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
149 #endif /* CONFIG_PPP_FILTER */
150         struct net      *ppp_net;       /* the net we belong to */
151         struct ppp_link_stats stats64;  /* 64 bit network stats */
152 };
153 
154 /*
155  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
156  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
157  * SC_MUST_COMP
158  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
159  * Bits in xstate: SC_COMP_RUN
160  */
161 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
162                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
163                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
164 
165 /*
166  * Private data structure for each channel.
167  * This includes the data structure used for multilink.
168  */
169 struct channel {
170         struct ppp_file file;           /* stuff for read/write/poll */
171         struct list_head list;          /* link in all/new_channels list */
172         struct ppp_channel *chan;       /* public channel data structure */
173         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
174         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
175         struct ppp      *ppp;           /* ppp unit we're connected to */
176         struct net      *chan_net;      /* the net channel belongs to */
177         struct list_head clist;         /* link in list of channels per unit */
178         rwlock_t        upl;            /* protects `ppp' */
179 #ifdef CONFIG_PPP_MULTILINK
180         u8              avail;          /* flag used in multilink stuff */
181         u8              had_frag;       /* >= 1 fragments have been sent */
182         u32             lastseq;        /* MP: last sequence # received */
183         int             speed;          /* speed of the corresponding ppp channel*/
184 #endif /* CONFIG_PPP_MULTILINK */
185 };
186 
187 struct ppp_config {
188         struct file *file;
189         s32 unit;
190         bool ifname_is_set;
191 };
192 
193 /*
194  * SMP locking issues:
195  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
196  * list and the ppp.n_channels field, you need to take both locks
197  * before you modify them.
198  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
199  * channel.downl.
200  */
201 
202 static DEFINE_MUTEX(ppp_mutex);
203 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
204 static atomic_t channel_count = ATOMIC_INIT(0);
205 
206 /* per-net private data for this module */
207 static int ppp_net_id __read_mostly;
208 struct ppp_net {
209         /* units to ppp mapping */
210         struct idr units_idr;
211 
212         /*
213          * all_ppp_mutex protects the units_idr mapping.
214          * It also ensures that finding a ppp unit in the units_idr
215          * map and updating its file.refcnt field is atomic.
216          */
217         struct mutex all_ppp_mutex;
218 
219         /* channels */
220         struct list_head all_channels;
221         struct list_head new_channels;
222         int last_channel_index;
223 
224         /*
225          * all_channels_lock protects all_channels and
226          * last_channel_index, and the atomicity of find
227          * a channel and updating its file.refcnt field.
228          */
229         spinlock_t all_channels_lock;
230 };
231 
232 /* Get the PPP protocol number from a skb */
233 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
234 
235 /* We limit the length of ppp->file.rq to this (arbitrary) value */
236 #define PPP_MAX_RQLEN   32
237 
238 /*
239  * Maximum number of multilink fragments queued up.
240  * This has to be large enough to cope with the maximum latency of
241  * the slowest channel relative to the others.  Strictly it should
242  * depend on the number of channels and their characteristics.
243  */
244 #define PPP_MP_MAX_QLEN 128
245 
246 /* Multilink header bits. */
247 #define B       0x80            /* this fragment begins a packet */
248 #define E       0x40            /* this fragment ends a packet */
249 
250 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
251 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
252 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
253 
254 /* Prototypes. */
255 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
256                         struct file *file, unsigned int cmd, unsigned long arg);
257 static void ppp_xmit_process(struct ppp *ppp);
258 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
259 static void ppp_push(struct ppp *ppp);
260 static void ppp_channel_push(struct channel *pch);
261 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
262                               struct channel *pch);
263 static void ppp_receive_error(struct ppp *ppp);
264 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
265 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
266                                             struct sk_buff *skb);
267 #ifdef CONFIG_PPP_MULTILINK
268 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
269                                 struct channel *pch);
270 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
271 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
272 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
273 #endif /* CONFIG_PPP_MULTILINK */
274 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
275 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
276 static void ppp_ccp_closed(struct ppp *ppp);
277 static struct compressor *find_compressor(int type);
278 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
279 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
280 static void init_ppp_file(struct ppp_file *pf, int kind);
281 static void ppp_destroy_interface(struct ppp *ppp);
282 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
283 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
284 static int ppp_connect_channel(struct channel *pch, int unit);
285 static int ppp_disconnect_channel(struct channel *pch);
286 static void ppp_destroy_channel(struct channel *pch);
287 static int unit_get(struct idr *p, void *ptr);
288 static int unit_set(struct idr *p, void *ptr, int n);
289 static void unit_put(struct idr *p, int n);
290 static void *unit_find(struct idr *p, int n);
291 static void ppp_setup(struct net_device *dev);
292 
293 static const struct net_device_ops ppp_netdev_ops;
294 
295 static struct class *ppp_class;
296 
297 /* per net-namespace data */
298 static inline struct ppp_net *ppp_pernet(struct net *net)
299 {
300         BUG_ON(!net);
301 
302         return net_generic(net, ppp_net_id);
303 }
304 
305 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
306 static inline int proto_to_npindex(int proto)
307 {
308         switch (proto) {
309         case PPP_IP:
310                 return NP_IP;
311         case PPP_IPV6:
312                 return NP_IPV6;
313         case PPP_IPX:
314                 return NP_IPX;
315         case PPP_AT:
316                 return NP_AT;
317         case PPP_MPLS_UC:
318                 return NP_MPLS_UC;
319         case PPP_MPLS_MC:
320                 return NP_MPLS_MC;
321         }
322         return -EINVAL;
323 }
324 
325 /* Translates an NP index into a PPP protocol number */
326 static const int npindex_to_proto[NUM_NP] = {
327         PPP_IP,
328         PPP_IPV6,
329         PPP_IPX,
330         PPP_AT,
331         PPP_MPLS_UC,
332         PPP_MPLS_MC,
333 };
334 
335 /* Translates an ethertype into an NP index */
336 static inline int ethertype_to_npindex(int ethertype)
337 {
338         switch (ethertype) {
339         case ETH_P_IP:
340                 return NP_IP;
341         case ETH_P_IPV6:
342                 return NP_IPV6;
343         case ETH_P_IPX:
344                 return NP_IPX;
345         case ETH_P_PPPTALK:
346         case ETH_P_ATALK:
347                 return NP_AT;
348         case ETH_P_MPLS_UC:
349                 return NP_MPLS_UC;
350         case ETH_P_MPLS_MC:
351                 return NP_MPLS_MC;
352         }
353         return -1;
354 }
355 
356 /* Translates an NP index into an ethertype */
357 static const int npindex_to_ethertype[NUM_NP] = {
358         ETH_P_IP,
359         ETH_P_IPV6,
360         ETH_P_IPX,
361         ETH_P_PPPTALK,
362         ETH_P_MPLS_UC,
363         ETH_P_MPLS_MC,
364 };
365 
366 /*
367  * Locking shorthand.
368  */
369 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
370 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
371 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
372 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
373 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
374                                      ppp_recv_lock(ppp); } while (0)
375 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
376                                      ppp_xmit_unlock(ppp); } while (0)
377 
378 /*
379  * /dev/ppp device routines.
380  * The /dev/ppp device is used by pppd to control the ppp unit.
381  * It supports the read, write, ioctl and poll functions.
382  * Open instances of /dev/ppp can be in one of three states:
383  * unattached, attached to a ppp unit, or attached to a ppp channel.
384  */
385 static int ppp_open(struct inode *inode, struct file *file)
386 {
387         /*
388          * This could (should?) be enforced by the permissions on /dev/ppp.
389          */
390         if (!capable(CAP_NET_ADMIN))
391                 return -EPERM;
392         return 0;
393 }
394 
395 static int ppp_release(struct inode *unused, struct file *file)
396 {
397         struct ppp_file *pf = file->private_data;
398         struct ppp *ppp;
399 
400         if (pf) {
401                 file->private_data = NULL;
402                 if (pf->kind == INTERFACE) {
403                         ppp = PF_TO_PPP(pf);
404                         rtnl_lock();
405                         if (file == ppp->owner)
406                                 unregister_netdevice(ppp->dev);
407                         rtnl_unlock();
408                 }
409                 if (atomic_dec_and_test(&pf->refcnt)) {
410                         switch (pf->kind) {
411                         case INTERFACE:
412                                 ppp_destroy_interface(PF_TO_PPP(pf));
413                                 break;
414                         case CHANNEL:
415                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
416                                 break;
417                         }
418                 }
419         }
420         return 0;
421 }
422 
423 static ssize_t ppp_read(struct file *file, char __user *buf,
424                         size_t count, loff_t *ppos)
425 {
426         struct ppp_file *pf = file->private_data;
427         DECLARE_WAITQUEUE(wait, current);
428         ssize_t ret;
429         struct sk_buff *skb = NULL;
430         struct iovec iov;
431         struct iov_iter to;
432 
433         ret = count;
434 
435         if (!pf)
436                 return -ENXIO;
437         add_wait_queue(&pf->rwait, &wait);
438         for (;;) {
439                 set_current_state(TASK_INTERRUPTIBLE);
440                 skb = skb_dequeue(&pf->rq);
441                 if (skb)
442                         break;
443                 ret = 0;
444                 if (pf->dead)
445                         break;
446                 if (pf->kind == INTERFACE) {
447                         /*
448                          * Return 0 (EOF) on an interface that has no
449                          * channels connected, unless it is looping
450                          * network traffic (demand mode).
451                          */
452                         struct ppp *ppp = PF_TO_PPP(pf);
453 
454                         ppp_recv_lock(ppp);
455                         if (ppp->n_channels == 0 &&
456                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
457                                 ppp_recv_unlock(ppp);
458                                 break;
459                         }
460                         ppp_recv_unlock(ppp);
461                 }
462                 ret = -EAGAIN;
463                 if (file->f_flags & O_NONBLOCK)
464                         break;
465                 ret = -ERESTARTSYS;
466                 if (signal_pending(current))
467                         break;
468                 schedule();
469         }
470         set_current_state(TASK_RUNNING);
471         remove_wait_queue(&pf->rwait, &wait);
472 
473         if (!skb)
474                 goto out;
475 
476         ret = -EOVERFLOW;
477         if (skb->len > count)
478                 goto outf;
479         ret = -EFAULT;
480         iov.iov_base = buf;
481         iov.iov_len = count;
482         iov_iter_init(&to, READ, &iov, 1, count);
483         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
484                 goto outf;
485         ret = skb->len;
486 
487  outf:
488         kfree_skb(skb);
489  out:
490         return ret;
491 }
492 
493 static ssize_t ppp_write(struct file *file, const char __user *buf,
494                          size_t count, loff_t *ppos)
495 {
496         struct ppp_file *pf = file->private_data;
497         struct sk_buff *skb;
498         ssize_t ret;
499 
500         if (!pf)
501                 return -ENXIO;
502         ret = -ENOMEM;
503         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
504         if (!skb)
505                 goto out;
506         skb_reserve(skb, pf->hdrlen);
507         ret = -EFAULT;
508         if (copy_from_user(skb_put(skb, count), buf, count)) {
509                 kfree_skb(skb);
510                 goto out;
511         }
512 
513         skb_queue_tail(&pf->xq, skb);
514 
515         switch (pf->kind) {
516         case INTERFACE:
517                 ppp_xmit_process(PF_TO_PPP(pf));
518                 break;
519         case CHANNEL:
520                 ppp_channel_push(PF_TO_CHANNEL(pf));
521                 break;
522         }
523 
524         ret = count;
525 
526  out:
527         return ret;
528 }
529 
530 /* No kernel lock - fine */
531 static unsigned int ppp_poll(struct file *file, poll_table *wait)
532 {
533         struct ppp_file *pf = file->private_data;
534         unsigned int mask;
535 
536         if (!pf)
537                 return 0;
538         poll_wait(file, &pf->rwait, wait);
539         mask = POLLOUT | POLLWRNORM;
540         if (skb_peek(&pf->rq))
541                 mask |= POLLIN | POLLRDNORM;
542         if (pf->dead)
543                 mask |= POLLHUP;
544         else if (pf->kind == INTERFACE) {
545                 /* see comment in ppp_read */
546                 struct ppp *ppp = PF_TO_PPP(pf);
547 
548                 ppp_recv_lock(ppp);
549                 if (ppp->n_channels == 0 &&
550                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
551                         mask |= POLLIN | POLLRDNORM;
552                 ppp_recv_unlock(ppp);
553         }
554 
555         return mask;
556 }
557 
558 #ifdef CONFIG_PPP_FILTER
559 static int get_filter(void __user *arg, struct sock_filter **p)
560 {
561         struct sock_fprog uprog;
562         struct sock_filter *code = NULL;
563         int len;
564 
565         if (copy_from_user(&uprog, arg, sizeof(uprog)))
566                 return -EFAULT;
567 
568         if (!uprog.len) {
569                 *p = NULL;
570                 return 0;
571         }
572 
573         len = uprog.len * sizeof(struct sock_filter);
574         code = memdup_user(uprog.filter, len);
575         if (IS_ERR(code))
576                 return PTR_ERR(code);
577 
578         *p = code;
579         return uprog.len;
580 }
581 #endif /* CONFIG_PPP_FILTER */
582 
583 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
584 {
585         struct ppp_file *pf;
586         struct ppp *ppp;
587         int err = -EFAULT, val, val2, i;
588         struct ppp_idle idle;
589         struct npioctl npi;
590         int unit, cflags;
591         struct slcompress *vj;
592         void __user *argp = (void __user *)arg;
593         int __user *p = argp;
594 
595         mutex_lock(&ppp_mutex);
596 
597         pf = file->private_data;
598         if (!pf) {
599                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
600                                            pf, file, cmd, arg);
601                 goto out;
602         }
603 
604         if (cmd == PPPIOCDETACH) {
605                 /*
606                  * We have to be careful here... if the file descriptor
607                  * has been dup'd, we could have another process in the
608                  * middle of a poll using the same file *, so we had
609                  * better not free the interface data structures -
610                  * instead we fail the ioctl.  Even in this case, we
611                  * shut down the interface if we are the owner of it.
612                  * Actually, we should get rid of PPPIOCDETACH, userland
613                  * (i.e. pppd) could achieve the same effect by closing
614                  * this fd and reopening /dev/ppp.
615                  */
616                 err = -EINVAL;
617                 if (pf->kind == INTERFACE) {
618                         ppp = PF_TO_PPP(pf);
619                         rtnl_lock();
620                         if (file == ppp->owner)
621                                 unregister_netdevice(ppp->dev);
622                         rtnl_unlock();
623                 }
624                 if (atomic_long_read(&file->f_count) < 2) {
625                         ppp_release(NULL, file);
626                         err = 0;
627                 } else
628                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
629                                 atomic_long_read(&file->f_count));
630                 goto out;
631         }
632 
633         if (pf->kind == CHANNEL) {
634                 struct channel *pch;
635                 struct ppp_channel *chan;
636 
637                 pch = PF_TO_CHANNEL(pf);
638 
639                 switch (cmd) {
640                 case PPPIOCCONNECT:
641                         if (get_user(unit, p))
642                                 break;
643                         err = ppp_connect_channel(pch, unit);
644                         break;
645 
646                 case PPPIOCDISCONN:
647                         err = ppp_disconnect_channel(pch);
648                         break;
649 
650                 default:
651                         down_read(&pch->chan_sem);
652                         chan = pch->chan;
653                         err = -ENOTTY;
654                         if (chan && chan->ops->ioctl)
655                                 err = chan->ops->ioctl(chan, cmd, arg);
656                         up_read(&pch->chan_sem);
657                 }
658                 goto out;
659         }
660 
661         if (pf->kind != INTERFACE) {
662                 /* can't happen */
663                 pr_err("PPP: not interface or channel??\n");
664                 err = -EINVAL;
665                 goto out;
666         }
667 
668         ppp = PF_TO_PPP(pf);
669         switch (cmd) {
670         case PPPIOCSMRU:
671                 if (get_user(val, p))
672                         break;
673                 ppp->mru = val;
674                 err = 0;
675                 break;
676 
677         case PPPIOCSFLAGS:
678                 if (get_user(val, p))
679                         break;
680                 ppp_lock(ppp);
681                 cflags = ppp->flags & ~val;
682 #ifdef CONFIG_PPP_MULTILINK
683                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
684                         ppp->nextseq = 0;
685 #endif
686                 ppp->flags = val & SC_FLAG_BITS;
687                 ppp_unlock(ppp);
688                 if (cflags & SC_CCP_OPEN)
689                         ppp_ccp_closed(ppp);
690                 err = 0;
691                 break;
692 
693         case PPPIOCGFLAGS:
694                 val = ppp->flags | ppp->xstate | ppp->rstate;
695                 if (put_user(val, p))
696                         break;
697                 err = 0;
698                 break;
699 
700         case PPPIOCSCOMPRESS:
701                 err = ppp_set_compress(ppp, arg);
702                 break;
703 
704         case PPPIOCGUNIT:
705                 if (put_user(ppp->file.index, p))
706                         break;
707                 err = 0;
708                 break;
709 
710         case PPPIOCSDEBUG:
711                 if (get_user(val, p))
712                         break;
713                 ppp->debug = val;
714                 err = 0;
715                 break;
716 
717         case PPPIOCGDEBUG:
718                 if (put_user(ppp->debug, p))
719                         break;
720                 err = 0;
721                 break;
722 
723         case PPPIOCGIDLE:
724                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
725                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
726                 if (copy_to_user(argp, &idle, sizeof(idle)))
727                         break;
728                 err = 0;
729                 break;
730 
731         case PPPIOCSMAXCID:
732                 if (get_user(val, p))
733                         break;
734                 val2 = 15;
735                 if ((val >> 16) != 0) {
736                         val2 = val >> 16;
737                         val &= 0xffff;
738                 }
739                 vj = slhc_init(val2+1, val+1);
740                 if (IS_ERR(vj)) {
741                         err = PTR_ERR(vj);
742                         break;
743                 }
744                 ppp_lock(ppp);
745                 if (ppp->vj)
746                         slhc_free(ppp->vj);
747                 ppp->vj = vj;
748                 ppp_unlock(ppp);
749                 err = 0;
750                 break;
751 
752         case PPPIOCGNPMODE:
753         case PPPIOCSNPMODE:
754                 if (copy_from_user(&npi, argp, sizeof(npi)))
755                         break;
756                 err = proto_to_npindex(npi.protocol);
757                 if (err < 0)
758                         break;
759                 i = err;
760                 if (cmd == PPPIOCGNPMODE) {
761                         err = -EFAULT;
762                         npi.mode = ppp->npmode[i];
763                         if (copy_to_user(argp, &npi, sizeof(npi)))
764                                 break;
765                 } else {
766                         ppp->npmode[i] = npi.mode;
767                         /* we may be able to transmit more packets now (??) */
768                         netif_wake_queue(ppp->dev);
769                 }
770                 err = 0;
771                 break;
772 
773 #ifdef CONFIG_PPP_FILTER
774         case PPPIOCSPASS:
775         {
776                 struct sock_filter *code;
777 
778                 err = get_filter(argp, &code);
779                 if (err >= 0) {
780                         struct bpf_prog *pass_filter = NULL;
781                         struct sock_fprog_kern fprog = {
782                                 .len = err,
783                                 .filter = code,
784                         };
785 
786                         err = 0;
787                         if (fprog.filter)
788                                 err = bpf_prog_create(&pass_filter, &fprog);
789                         if (!err) {
790                                 ppp_lock(ppp);
791                                 if (ppp->pass_filter)
792                                         bpf_prog_destroy(ppp->pass_filter);
793                                 ppp->pass_filter = pass_filter;
794                                 ppp_unlock(ppp);
795                         }
796                         kfree(code);
797                 }
798                 break;
799         }
800         case PPPIOCSACTIVE:
801         {
802                 struct sock_filter *code;
803 
804                 err = get_filter(argp, &code);
805                 if (err >= 0) {
806                         struct bpf_prog *active_filter = NULL;
807                         struct sock_fprog_kern fprog = {
808                                 .len = err,
809                                 .filter = code,
810                         };
811 
812                         err = 0;
813                         if (fprog.filter)
814                                 err = bpf_prog_create(&active_filter, &fprog);
815                         if (!err) {
816                                 ppp_lock(ppp);
817                                 if (ppp->active_filter)
818                                         bpf_prog_destroy(ppp->active_filter);
819                                 ppp->active_filter = active_filter;
820                                 ppp_unlock(ppp);
821                         }
822                         kfree(code);
823                 }
824                 break;
825         }
826 #endif /* CONFIG_PPP_FILTER */
827 
828 #ifdef CONFIG_PPP_MULTILINK
829         case PPPIOCSMRRU:
830                 if (get_user(val, p))
831                         break;
832                 ppp_recv_lock(ppp);
833                 ppp->mrru = val;
834                 ppp_recv_unlock(ppp);
835                 err = 0;
836                 break;
837 #endif /* CONFIG_PPP_MULTILINK */
838 
839         default:
840                 err = -ENOTTY;
841         }
842 
843 out:
844         mutex_unlock(&ppp_mutex);
845 
846         return err;
847 }
848 
849 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
850                         struct file *file, unsigned int cmd, unsigned long arg)
851 {
852         int unit, err = -EFAULT;
853         struct ppp *ppp;
854         struct channel *chan;
855         struct ppp_net *pn;
856         int __user *p = (int __user *)arg;
857 
858         switch (cmd) {
859         case PPPIOCNEWUNIT:
860                 /* Create a new ppp unit */
861                 if (get_user(unit, p))
862                         break;
863                 err = ppp_create_interface(net, file, &unit);
864                 if (err < 0)
865                         break;
866 
867                 err = -EFAULT;
868                 if (put_user(unit, p))
869                         break;
870                 err = 0;
871                 break;
872 
873         case PPPIOCATTACH:
874                 /* Attach to an existing ppp unit */
875                 if (get_user(unit, p))
876                         break;
877                 err = -ENXIO;
878                 pn = ppp_pernet(net);
879                 mutex_lock(&pn->all_ppp_mutex);
880                 ppp = ppp_find_unit(pn, unit);
881                 if (ppp) {
882                         atomic_inc(&ppp->file.refcnt);
883                         file->private_data = &ppp->file;
884                         err = 0;
885                 }
886                 mutex_unlock(&pn->all_ppp_mutex);
887                 break;
888 
889         case PPPIOCATTCHAN:
890                 if (get_user(unit, p))
891                         break;
892                 err = -ENXIO;
893                 pn = ppp_pernet(net);
894                 spin_lock_bh(&pn->all_channels_lock);
895                 chan = ppp_find_channel(pn, unit);
896                 if (chan) {
897                         atomic_inc(&chan->file.refcnt);
898                         file->private_data = &chan->file;
899                         err = 0;
900                 }
901                 spin_unlock_bh(&pn->all_channels_lock);
902                 break;
903 
904         default:
905                 err = -ENOTTY;
906         }
907 
908         return err;
909 }
910 
911 static const struct file_operations ppp_device_fops = {
912         .owner          = THIS_MODULE,
913         .read           = ppp_read,
914         .write          = ppp_write,
915         .poll           = ppp_poll,
916         .unlocked_ioctl = ppp_ioctl,
917         .open           = ppp_open,
918         .release        = ppp_release,
919         .llseek         = noop_llseek,
920 };
921 
922 static __net_init int ppp_init_net(struct net *net)
923 {
924         struct ppp_net *pn = net_generic(net, ppp_net_id);
925 
926         idr_init(&pn->units_idr);
927         mutex_init(&pn->all_ppp_mutex);
928 
929         INIT_LIST_HEAD(&pn->all_channels);
930         INIT_LIST_HEAD(&pn->new_channels);
931 
932         spin_lock_init(&pn->all_channels_lock);
933 
934         return 0;
935 }
936 
937 static __net_exit void ppp_exit_net(struct net *net)
938 {
939         struct ppp_net *pn = net_generic(net, ppp_net_id);
940         struct net_device *dev;
941         struct net_device *aux;
942         struct ppp *ppp;
943         LIST_HEAD(list);
944         int id;
945 
946         rtnl_lock();
947         for_each_netdev_safe(net, dev, aux) {
948                 if (dev->netdev_ops == &ppp_netdev_ops)
949                         unregister_netdevice_queue(dev, &list);
950         }
951 
952         idr_for_each_entry(&pn->units_idr, ppp, id)
953                 /* Skip devices already unregistered by previous loop */
954                 if (!net_eq(dev_net(ppp->dev), net))
955                         unregister_netdevice_queue(ppp->dev, &list);
956 
957         unregister_netdevice_many(&list);
958         rtnl_unlock();
959 
960         idr_destroy(&pn->units_idr);
961 }
962 
963 static struct pernet_operations ppp_net_ops = {
964         .init = ppp_init_net,
965         .exit = ppp_exit_net,
966         .id   = &ppp_net_id,
967         .size = sizeof(struct ppp_net),
968 };
969 
970 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
971 {
972         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
973         int ret;
974 
975         mutex_lock(&pn->all_ppp_mutex);
976 
977         if (unit < 0) {
978                 ret = unit_get(&pn->units_idr, ppp);
979                 if (ret < 0)
980                         goto err;
981         } else {
982                 /* Caller asked for a specific unit number. Fail with -EEXIST
983                  * if unavailable. For backward compatibility, return -EEXIST
984                  * too if idr allocation fails; this makes pppd retry without
985                  * requesting a specific unit number.
986                  */
987                 if (unit_find(&pn->units_idr, unit)) {
988                         ret = -EEXIST;
989                         goto err;
990                 }
991                 ret = unit_set(&pn->units_idr, ppp, unit);
992                 if (ret < 0) {
993                         /* Rewrite error for backward compatibility */
994                         ret = -EEXIST;
995                         goto err;
996                 }
997         }
998         ppp->file.index = ret;
999 
1000         if (!ifname_is_set)
1001                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1002 
1003         ret = register_netdevice(ppp->dev);
1004         if (ret < 0)
1005                 goto err_unit;
1006 
1007         atomic_inc(&ppp_unit_count);
1008 
1009         mutex_unlock(&pn->all_ppp_mutex);
1010 
1011         return 0;
1012 
1013 err_unit:
1014         unit_put(&pn->units_idr, ppp->file.index);
1015 err:
1016         mutex_unlock(&pn->all_ppp_mutex);
1017 
1018         return ret;
1019 }
1020 
1021 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1022                              const struct ppp_config *conf)
1023 {
1024         struct ppp *ppp = netdev_priv(dev);
1025         int indx;
1026         int err;
1027 
1028         ppp->dev = dev;
1029         ppp->ppp_net = src_net;
1030         ppp->mru = PPP_MRU;
1031         ppp->owner = conf->file;
1032 
1033         init_ppp_file(&ppp->file, INTERFACE);
1034         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1035 
1036         for (indx = 0; indx < NUM_NP; ++indx)
1037                 ppp->npmode[indx] = NPMODE_PASS;
1038         INIT_LIST_HEAD(&ppp->channels);
1039         spin_lock_init(&ppp->rlock);
1040         spin_lock_init(&ppp->wlock);
1041 #ifdef CONFIG_PPP_MULTILINK
1042         ppp->minseq = -1;
1043         skb_queue_head_init(&ppp->mrq);
1044 #endif /* CONFIG_PPP_MULTILINK */
1045 #ifdef CONFIG_PPP_FILTER
1046         ppp->pass_filter = NULL;
1047         ppp->active_filter = NULL;
1048 #endif /* CONFIG_PPP_FILTER */
1049 
1050         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1051         if (err < 0)
1052                 return err;
1053 
1054         conf->file->private_data = &ppp->file;
1055 
1056         return 0;
1057 }
1058 
1059 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1060         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1061 };
1062 
1063 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[])
1064 {
1065         if (!data)
1066                 return -EINVAL;
1067 
1068         if (!data[IFLA_PPP_DEV_FD])
1069                 return -EINVAL;
1070         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1071                 return -EBADF;
1072 
1073         return 0;
1074 }
1075 
1076 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1077                           struct nlattr *tb[], struct nlattr *data[])
1078 {
1079         struct ppp_config conf = {
1080                 .unit = -1,
1081                 .ifname_is_set = true,
1082         };
1083         struct file *file;
1084         int err;
1085 
1086         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1087         if (!file)
1088                 return -EBADF;
1089 
1090         /* rtnl_lock is already held here, but ppp_create_interface() locks
1091          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1092          * possible deadlock due to lock order inversion, at the cost of
1093          * pushing the problem back to userspace.
1094          */
1095         if (!mutex_trylock(&ppp_mutex)) {
1096                 err = -EBUSY;
1097                 goto out;
1098         }
1099 
1100         if (file->f_op != &ppp_device_fops || file->private_data) {
1101                 err = -EBADF;
1102                 goto out_unlock;
1103         }
1104 
1105         conf.file = file;
1106         err = ppp_dev_configure(src_net, dev, &conf);
1107 
1108 out_unlock:
1109         mutex_unlock(&ppp_mutex);
1110 out:
1111         fput(file);
1112 
1113         return err;
1114 }
1115 
1116 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1117 {
1118         unregister_netdevice_queue(dev, head);
1119 }
1120 
1121 static size_t ppp_nl_get_size(const struct net_device *dev)
1122 {
1123         return 0;
1124 }
1125 
1126 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1127 {
1128         return 0;
1129 }
1130 
1131 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1132 {
1133         struct ppp *ppp = netdev_priv(dev);
1134 
1135         return ppp->ppp_net;
1136 }
1137 
1138 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1139         .kind           = "ppp",
1140         .maxtype        = IFLA_PPP_MAX,
1141         .policy         = ppp_nl_policy,
1142         .priv_size      = sizeof(struct ppp),
1143         .setup          = ppp_setup,
1144         .validate       = ppp_nl_validate,
1145         .newlink        = ppp_nl_newlink,
1146         .dellink        = ppp_nl_dellink,
1147         .get_size       = ppp_nl_get_size,
1148         .fill_info      = ppp_nl_fill_info,
1149         .get_link_net   = ppp_nl_get_link_net,
1150 };
1151 
1152 #define PPP_MAJOR       108
1153 
1154 /* Called at boot time if ppp is compiled into the kernel,
1155    or at module load time (from init_module) if compiled as a module. */
1156 static int __init ppp_init(void)
1157 {
1158         int err;
1159 
1160         pr_info("PPP generic driver version " PPP_VERSION "\n");
1161 
1162         err = register_pernet_device(&ppp_net_ops);
1163         if (err) {
1164                 pr_err("failed to register PPP pernet device (%d)\n", err);
1165                 goto out;
1166         }
1167 
1168         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1169         if (err) {
1170                 pr_err("failed to register PPP device (%d)\n", err);
1171                 goto out_net;
1172         }
1173 
1174         ppp_class = class_create(THIS_MODULE, "ppp");
1175         if (IS_ERR(ppp_class)) {
1176                 err = PTR_ERR(ppp_class);
1177                 goto out_chrdev;
1178         }
1179 
1180         err = rtnl_link_register(&ppp_link_ops);
1181         if (err) {
1182                 pr_err("failed to register rtnetlink PPP handler\n");
1183                 goto out_class;
1184         }
1185 
1186         /* not a big deal if we fail here :-) */
1187         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1188 
1189         return 0;
1190 
1191 out_class:
1192         class_destroy(ppp_class);
1193 out_chrdev:
1194         unregister_chrdev(PPP_MAJOR, "ppp");
1195 out_net:
1196         unregister_pernet_device(&ppp_net_ops);
1197 out:
1198         return err;
1199 }
1200 
1201 /*
1202  * Network interface unit routines.
1203  */
1204 static netdev_tx_t
1205 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1206 {
1207         struct ppp *ppp = netdev_priv(dev);
1208         int npi, proto;
1209         unsigned char *pp;
1210 
1211         npi = ethertype_to_npindex(ntohs(skb->protocol));
1212         if (npi < 0)
1213                 goto outf;
1214 
1215         /* Drop, accept or reject the packet */
1216         switch (ppp->npmode[npi]) {
1217         case NPMODE_PASS:
1218                 break;
1219         case NPMODE_QUEUE:
1220                 /* it would be nice to have a way to tell the network
1221                    system to queue this one up for later. */
1222                 goto outf;
1223         case NPMODE_DROP:
1224         case NPMODE_ERROR:
1225                 goto outf;
1226         }
1227 
1228         /* Put the 2-byte PPP protocol number on the front,
1229            making sure there is room for the address and control fields. */
1230         if (skb_cow_head(skb, PPP_HDRLEN))
1231                 goto outf;
1232 
1233         pp = skb_push(skb, 2);
1234         proto = npindex_to_proto[npi];
1235         put_unaligned_be16(proto, pp);
1236 
1237         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1238         skb_queue_tail(&ppp->file.xq, skb);
1239         ppp_xmit_process(ppp);
1240         return NETDEV_TX_OK;
1241 
1242  outf:
1243         kfree_skb(skb);
1244         ++dev->stats.tx_dropped;
1245         return NETDEV_TX_OK;
1246 }
1247 
1248 static int
1249 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1250 {
1251         struct ppp *ppp = netdev_priv(dev);
1252         int err = -EFAULT;
1253         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1254         struct ppp_stats stats;
1255         struct ppp_comp_stats cstats;
1256         char *vers;
1257 
1258         switch (cmd) {
1259         case SIOCGPPPSTATS:
1260                 ppp_get_stats(ppp, &stats);
1261                 if (copy_to_user(addr, &stats, sizeof(stats)))
1262                         break;
1263                 err = 0;
1264                 break;
1265 
1266         case SIOCGPPPCSTATS:
1267                 memset(&cstats, 0, sizeof(cstats));
1268                 if (ppp->xc_state)
1269                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1270                 if (ppp->rc_state)
1271                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1272                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1273                         break;
1274                 err = 0;
1275                 break;
1276 
1277         case SIOCGPPPVER:
1278                 vers = PPP_VERSION;
1279                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1280                         break;
1281                 err = 0;
1282                 break;
1283 
1284         default:
1285                 err = -EINVAL;
1286         }
1287 
1288         return err;
1289 }
1290 
1291 static struct rtnl_link_stats64*
1292 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1293 {
1294         struct ppp *ppp = netdev_priv(dev);
1295 
1296         ppp_recv_lock(ppp);
1297         stats64->rx_packets = ppp->stats64.rx_packets;
1298         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1299         ppp_recv_unlock(ppp);
1300 
1301         ppp_xmit_lock(ppp);
1302         stats64->tx_packets = ppp->stats64.tx_packets;
1303         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1304         ppp_xmit_unlock(ppp);
1305 
1306         stats64->rx_errors        = dev->stats.rx_errors;
1307         stats64->tx_errors        = dev->stats.tx_errors;
1308         stats64->rx_dropped       = dev->stats.rx_dropped;
1309         stats64->tx_dropped       = dev->stats.tx_dropped;
1310         stats64->rx_length_errors = dev->stats.rx_length_errors;
1311 
1312         return stats64;
1313 }
1314 
1315 static int ppp_dev_init(struct net_device *dev)
1316 {
1317         netdev_lockdep_set_classes(dev);
1318         return 0;
1319 }
1320 
1321 static void ppp_dev_uninit(struct net_device *dev)
1322 {
1323         struct ppp *ppp = netdev_priv(dev);
1324         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1325 
1326         ppp_lock(ppp);
1327         ppp->closing = 1;
1328         ppp_unlock(ppp);
1329 
1330         mutex_lock(&pn->all_ppp_mutex);
1331         unit_put(&pn->units_idr, ppp->file.index);
1332         mutex_unlock(&pn->all_ppp_mutex);
1333 
1334         ppp->owner = NULL;
1335 
1336         ppp->file.dead = 1;
1337         wake_up_interruptible(&ppp->file.rwait);
1338 }
1339 
1340 static const struct net_device_ops ppp_netdev_ops = {
1341         .ndo_init        = ppp_dev_init,
1342         .ndo_uninit      = ppp_dev_uninit,
1343         .ndo_start_xmit  = ppp_start_xmit,
1344         .ndo_do_ioctl    = ppp_net_ioctl,
1345         .ndo_get_stats64 = ppp_get_stats64,
1346 };
1347 
1348 static struct device_type ppp_type = {
1349         .name = "ppp",
1350 };
1351 
1352 static void ppp_setup(struct net_device *dev)
1353 {
1354         dev->netdev_ops = &ppp_netdev_ops;
1355         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1356 
1357         dev->hard_header_len = PPP_HDRLEN;
1358         dev->mtu = PPP_MRU;
1359         dev->addr_len = 0;
1360         dev->tx_queue_len = 3;
1361         dev->type = ARPHRD_PPP;
1362         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1363         netif_keep_dst(dev);
1364 }
1365 
1366 /*
1367  * Transmit-side routines.
1368  */
1369 
1370 /*
1371  * Called to do any work queued up on the transmit side
1372  * that can now be done.
1373  */
1374 static void
1375 ppp_xmit_process(struct ppp *ppp)
1376 {
1377         struct sk_buff *skb;
1378 
1379         ppp_xmit_lock(ppp);
1380         if (!ppp->closing) {
1381                 ppp_push(ppp);
1382                 while (!ppp->xmit_pending &&
1383                        (skb = skb_dequeue(&ppp->file.xq)))
1384                         ppp_send_frame(ppp, skb);
1385                 /* If there's no work left to do, tell the core net
1386                    code that we can accept some more. */
1387                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1388                         netif_wake_queue(ppp->dev);
1389                 else
1390                         netif_stop_queue(ppp->dev);
1391         }
1392         ppp_xmit_unlock(ppp);
1393 }
1394 
1395 static inline struct sk_buff *
1396 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1397 {
1398         struct sk_buff *new_skb;
1399         int len;
1400         int new_skb_size = ppp->dev->mtu +
1401                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1402         int compressor_skb_size = ppp->dev->mtu +
1403                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1404         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1405         if (!new_skb) {
1406                 if (net_ratelimit())
1407                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1408                 return NULL;
1409         }
1410         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1411                 skb_reserve(new_skb,
1412                             ppp->dev->hard_header_len - PPP_HDRLEN);
1413 
1414         /* compressor still expects A/C bytes in hdr */
1415         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1416                                    new_skb->data, skb->len + 2,
1417                                    compressor_skb_size);
1418         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1419                 consume_skb(skb);
1420                 skb = new_skb;
1421                 skb_put(skb, len);
1422                 skb_pull(skb, 2);       /* pull off A/C bytes */
1423         } else if (len == 0) {
1424                 /* didn't compress, or CCP not up yet */
1425                 consume_skb(new_skb);
1426                 new_skb = skb;
1427         } else {
1428                 /*
1429                  * (len < 0)
1430                  * MPPE requires that we do not send unencrypted
1431                  * frames.  The compressor will return -1 if we
1432                  * should drop the frame.  We cannot simply test
1433                  * the compress_proto because MPPE and MPPC share
1434                  * the same number.
1435                  */
1436                 if (net_ratelimit())
1437                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1438                 kfree_skb(skb);
1439                 consume_skb(new_skb);
1440                 new_skb = NULL;
1441         }
1442         return new_skb;
1443 }
1444 
1445 /*
1446  * Compress and send a frame.
1447  * The caller should have locked the xmit path,
1448  * and xmit_pending should be 0.
1449  */
1450 static void
1451 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1452 {
1453         int proto = PPP_PROTO(skb);
1454         struct sk_buff *new_skb;
1455         int len;
1456         unsigned char *cp;
1457 
1458         if (proto < 0x8000) {
1459 #ifdef CONFIG_PPP_FILTER
1460                 /* check if we should pass this packet */
1461                 /* the filter instructions are constructed assuming
1462                    a four-byte PPP header on each packet */
1463                 *skb_push(skb, 2) = 1;
1464                 if (ppp->pass_filter &&
1465                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1466                         if (ppp->debug & 1)
1467                                 netdev_printk(KERN_DEBUG, ppp->dev,
1468                                               "PPP: outbound frame "
1469                                               "not passed\n");
1470                         kfree_skb(skb);
1471                         return;
1472                 }
1473                 /* if this packet passes the active filter, record the time */
1474                 if (!(ppp->active_filter &&
1475                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1476                         ppp->last_xmit = jiffies;
1477                 skb_pull(skb, 2);
1478 #else
1479                 /* for data packets, record the time */
1480                 ppp->last_xmit = jiffies;
1481 #endif /* CONFIG_PPP_FILTER */
1482         }
1483 
1484         ++ppp->stats64.tx_packets;
1485         ppp->stats64.tx_bytes += skb->len - 2;
1486 
1487         switch (proto) {
1488         case PPP_IP:
1489                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1490                         break;
1491                 /* try to do VJ TCP header compression */
1492                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1493                                     GFP_ATOMIC);
1494                 if (!new_skb) {
1495                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1496                         goto drop;
1497                 }
1498                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1499                 cp = skb->data + 2;
1500                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1501                                     new_skb->data + 2, &cp,
1502                                     !(ppp->flags & SC_NO_TCP_CCID));
1503                 if (cp == skb->data + 2) {
1504                         /* didn't compress */
1505                         consume_skb(new_skb);
1506                 } else {
1507                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1508                                 proto = PPP_VJC_COMP;
1509                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1510                         } else {
1511                                 proto = PPP_VJC_UNCOMP;
1512                                 cp[0] = skb->data[2];
1513                         }
1514                         consume_skb(skb);
1515                         skb = new_skb;
1516                         cp = skb_put(skb, len + 2);
1517                         cp[0] = 0;
1518                         cp[1] = proto;
1519                 }
1520                 break;
1521 
1522         case PPP_CCP:
1523                 /* peek at outbound CCP frames */
1524                 ppp_ccp_peek(ppp, skb, 0);
1525                 break;
1526         }
1527 
1528         /* try to do packet compression */
1529         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1530             proto != PPP_LCP && proto != PPP_CCP) {
1531                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1532                         if (net_ratelimit())
1533                                 netdev_err(ppp->dev,
1534                                            "ppp: compression required but "
1535                                            "down - pkt dropped.\n");
1536                         goto drop;
1537                 }
1538                 skb = pad_compress_skb(ppp, skb);
1539                 if (!skb)
1540                         goto drop;
1541         }
1542 
1543         /*
1544          * If we are waiting for traffic (demand dialling),
1545          * queue it up for pppd to receive.
1546          */
1547         if (ppp->flags & SC_LOOP_TRAFFIC) {
1548                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1549                         goto drop;
1550                 skb_queue_tail(&ppp->file.rq, skb);
1551                 wake_up_interruptible(&ppp->file.rwait);
1552                 return;
1553         }
1554 
1555         ppp->xmit_pending = skb;
1556         ppp_push(ppp);
1557         return;
1558 
1559  drop:
1560         kfree_skb(skb);
1561         ++ppp->dev->stats.tx_errors;
1562 }
1563 
1564 /*
1565  * Try to send the frame in xmit_pending.
1566  * The caller should have the xmit path locked.
1567  */
1568 static void
1569 ppp_push(struct ppp *ppp)
1570 {
1571         struct list_head *list;
1572         struct channel *pch;
1573         struct sk_buff *skb = ppp->xmit_pending;
1574 
1575         if (!skb)
1576                 return;
1577 
1578         list = &ppp->channels;
1579         if (list_empty(list)) {
1580                 /* nowhere to send the packet, just drop it */
1581                 ppp->xmit_pending = NULL;
1582                 kfree_skb(skb);
1583                 return;
1584         }
1585 
1586         if ((ppp->flags & SC_MULTILINK) == 0) {
1587                 /* not doing multilink: send it down the first channel */
1588                 list = list->next;
1589                 pch = list_entry(list, struct channel, clist);
1590 
1591                 spin_lock_bh(&pch->downl);
1592                 if (pch->chan) {
1593                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1594                                 ppp->xmit_pending = NULL;
1595                 } else {
1596                         /* channel got unregistered */
1597                         kfree_skb(skb);
1598                         ppp->xmit_pending = NULL;
1599                 }
1600                 spin_unlock_bh(&pch->downl);
1601                 return;
1602         }
1603 
1604 #ifdef CONFIG_PPP_MULTILINK
1605         /* Multilink: fragment the packet over as many links
1606            as can take the packet at the moment. */
1607         if (!ppp_mp_explode(ppp, skb))
1608                 return;
1609 #endif /* CONFIG_PPP_MULTILINK */
1610 
1611         ppp->xmit_pending = NULL;
1612         kfree_skb(skb);
1613 }
1614 
1615 #ifdef CONFIG_PPP_MULTILINK
1616 static bool mp_protocol_compress __read_mostly = true;
1617 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1618 MODULE_PARM_DESC(mp_protocol_compress,
1619                  "compress protocol id in multilink fragments");
1620 
1621 /*
1622  * Divide a packet to be transmitted into fragments and
1623  * send them out the individual links.
1624  */
1625 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1626 {
1627         int len, totlen;
1628         int i, bits, hdrlen, mtu;
1629         int flen;
1630         int navail, nfree, nzero;
1631         int nbigger;
1632         int totspeed;
1633         int totfree;
1634         unsigned char *p, *q;
1635         struct list_head *list;
1636         struct channel *pch;
1637         struct sk_buff *frag;
1638         struct ppp_channel *chan;
1639 
1640         totspeed = 0; /*total bitrate of the bundle*/
1641         nfree = 0; /* # channels which have no packet already queued */
1642         navail = 0; /* total # of usable channels (not deregistered) */
1643         nzero = 0; /* number of channels with zero speed associated*/
1644         totfree = 0; /*total # of channels available and
1645                                   *having no queued packets before
1646                                   *starting the fragmentation*/
1647 
1648         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1649         i = 0;
1650         list_for_each_entry(pch, &ppp->channels, clist) {
1651                 if (pch->chan) {
1652                         pch->avail = 1;
1653                         navail++;
1654                         pch->speed = pch->chan->speed;
1655                 } else {
1656                         pch->avail = 0;
1657                 }
1658                 if (pch->avail) {
1659                         if (skb_queue_empty(&pch->file.xq) ||
1660                                 !pch->had_frag) {
1661                                         if (pch->speed == 0)
1662                                                 nzero++;
1663                                         else
1664                                                 totspeed += pch->speed;
1665 
1666                                         pch->avail = 2;
1667                                         ++nfree;
1668                                         ++totfree;
1669                                 }
1670                         if (!pch->had_frag && i < ppp->nxchan)
1671                                 ppp->nxchan = i;
1672                 }
1673                 ++i;
1674         }
1675         /*
1676          * Don't start sending this packet unless at least half of
1677          * the channels are free.  This gives much better TCP
1678          * performance if we have a lot of channels.
1679          */
1680         if (nfree == 0 || nfree < navail / 2)
1681                 return 0; /* can't take now, leave it in xmit_pending */
1682 
1683         /* Do protocol field compression */
1684         p = skb->data;
1685         len = skb->len;
1686         if (*p == 0 && mp_protocol_compress) {
1687                 ++p;
1688                 --len;
1689         }
1690 
1691         totlen = len;
1692         nbigger = len % nfree;
1693 
1694         /* skip to the channel after the one we last used
1695            and start at that one */
1696         list = &ppp->channels;
1697         for (i = 0; i < ppp->nxchan; ++i) {
1698                 list = list->next;
1699                 if (list == &ppp->channels) {
1700                         i = 0;
1701                         break;
1702                 }
1703         }
1704 
1705         /* create a fragment for each channel */
1706         bits = B;
1707         while (len > 0) {
1708                 list = list->next;
1709                 if (list == &ppp->channels) {
1710                         i = 0;
1711                         continue;
1712                 }
1713                 pch = list_entry(list, struct channel, clist);
1714                 ++i;
1715                 if (!pch->avail)
1716                         continue;
1717 
1718                 /*
1719                  * Skip this channel if it has a fragment pending already and
1720                  * we haven't given a fragment to all of the free channels.
1721                  */
1722                 if (pch->avail == 1) {
1723                         if (nfree > 0)
1724                                 continue;
1725                 } else {
1726                         pch->avail = 1;
1727                 }
1728 
1729                 /* check the channel's mtu and whether it is still attached. */
1730                 spin_lock_bh(&pch->downl);
1731                 if (pch->chan == NULL) {
1732                         /* can't use this channel, it's being deregistered */
1733                         if (pch->speed == 0)
1734                                 nzero--;
1735                         else
1736                                 totspeed -= pch->speed;
1737 
1738                         spin_unlock_bh(&pch->downl);
1739                         pch->avail = 0;
1740                         totlen = len;
1741                         totfree--;
1742                         nfree--;
1743                         if (--navail == 0)
1744                                 break;
1745                         continue;
1746                 }
1747 
1748                 /*
1749                 *if the channel speed is not set divide
1750                 *the packet evenly among the free channels;
1751                 *otherwise divide it according to the speed
1752                 *of the channel we are going to transmit on
1753                 */
1754                 flen = len;
1755                 if (nfree > 0) {
1756                         if (pch->speed == 0) {
1757                                 flen = len/nfree;
1758                                 if (nbigger > 0) {
1759                                         flen++;
1760                                         nbigger--;
1761                                 }
1762                         } else {
1763                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1764                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1765                                 if (nbigger > 0) {
1766                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1767                                         nbigger -= ((totfree - nzero)*pch->speed)/
1768                                                         totspeed;
1769                                 }
1770                         }
1771                         nfree--;
1772                 }
1773 
1774                 /*
1775                  *check if we are on the last channel or
1776                  *we exceded the length of the data to
1777                  *fragment
1778                  */
1779                 if ((nfree <= 0) || (flen > len))
1780                         flen = len;
1781                 /*
1782                  *it is not worth to tx on slow channels:
1783                  *in that case from the resulting flen according to the
1784                  *above formula will be equal or less than zero.
1785                  *Skip the channel in this case
1786                  */
1787                 if (flen <= 0) {
1788                         pch->avail = 2;
1789                         spin_unlock_bh(&pch->downl);
1790                         continue;
1791                 }
1792 
1793                 /*
1794                  * hdrlen includes the 2-byte PPP protocol field, but the
1795                  * MTU counts only the payload excluding the protocol field.
1796                  * (RFC1661 Section 2)
1797                  */
1798                 mtu = pch->chan->mtu - (hdrlen - 2);
1799                 if (mtu < 4)
1800                         mtu = 4;
1801                 if (flen > mtu)
1802                         flen = mtu;
1803                 if (flen == len)
1804                         bits |= E;
1805                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1806                 if (!frag)
1807                         goto noskb;
1808                 q = skb_put(frag, flen + hdrlen);
1809 
1810                 /* make the MP header */
1811                 put_unaligned_be16(PPP_MP, q);
1812                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1813                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1814                         q[3] = ppp->nxseq;
1815                 } else {
1816                         q[2] = bits;
1817                         q[3] = ppp->nxseq >> 16;
1818                         q[4] = ppp->nxseq >> 8;
1819                         q[5] = ppp->nxseq;
1820                 }
1821 
1822                 memcpy(q + hdrlen, p, flen);
1823 
1824                 /* try to send it down the channel */
1825                 chan = pch->chan;
1826                 if (!skb_queue_empty(&pch->file.xq) ||
1827                         !chan->ops->start_xmit(chan, frag))
1828                         skb_queue_tail(&pch->file.xq, frag);
1829                 pch->had_frag = 1;
1830                 p += flen;
1831                 len -= flen;
1832                 ++ppp->nxseq;
1833                 bits = 0;
1834                 spin_unlock_bh(&pch->downl);
1835         }
1836         ppp->nxchan = i;
1837 
1838         return 1;
1839 
1840  noskb:
1841         spin_unlock_bh(&pch->downl);
1842         if (ppp->debug & 1)
1843                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1844         ++ppp->dev->stats.tx_errors;
1845         ++ppp->nxseq;
1846         return 1;       /* abandon the frame */
1847 }
1848 #endif /* CONFIG_PPP_MULTILINK */
1849 
1850 /*
1851  * Try to send data out on a channel.
1852  */
1853 static void
1854 ppp_channel_push(struct channel *pch)
1855 {
1856         struct sk_buff *skb;
1857         struct ppp *ppp;
1858 
1859         spin_lock_bh(&pch->downl);
1860         if (pch->chan) {
1861                 while (!skb_queue_empty(&pch->file.xq)) {
1862                         skb = skb_dequeue(&pch->file.xq);
1863                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1864                                 /* put the packet back and try again later */
1865                                 skb_queue_head(&pch->file.xq, skb);
1866                                 break;
1867                         }
1868                 }
1869         } else {
1870                 /* channel got deregistered */
1871                 skb_queue_purge(&pch->file.xq);
1872         }
1873         spin_unlock_bh(&pch->downl);
1874         /* see if there is anything from the attached unit to be sent */
1875         if (skb_queue_empty(&pch->file.xq)) {
1876                 read_lock_bh(&pch->upl);
1877                 ppp = pch->ppp;
1878                 if (ppp)
1879                         ppp_xmit_process(ppp);
1880                 read_unlock_bh(&pch->upl);
1881         }
1882 }
1883 
1884 /*
1885  * Receive-side routines.
1886  */
1887 
1888 struct ppp_mp_skb_parm {
1889         u32             sequence;
1890         u8              BEbits;
1891 };
1892 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1893 
1894 static inline void
1895 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1896 {
1897         ppp_recv_lock(ppp);
1898         if (!ppp->closing)
1899                 ppp_receive_frame(ppp, skb, pch);
1900         else
1901                 kfree_skb(skb);
1902         ppp_recv_unlock(ppp);
1903 }
1904 
1905 void
1906 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1907 {
1908         struct channel *pch = chan->ppp;
1909         int proto;
1910 
1911         if (!pch) {
1912                 kfree_skb(skb);
1913                 return;
1914         }
1915 
1916         read_lock_bh(&pch->upl);
1917         if (!pskb_may_pull(skb, 2)) {
1918                 kfree_skb(skb);
1919                 if (pch->ppp) {
1920                         ++pch->ppp->dev->stats.rx_length_errors;
1921                         ppp_receive_error(pch->ppp);
1922                 }
1923                 goto done;
1924         }
1925 
1926         proto = PPP_PROTO(skb);
1927         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1928                 /* put it on the channel queue */
1929                 skb_queue_tail(&pch->file.rq, skb);
1930                 /* drop old frames if queue too long */
1931                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1932                        (skb = skb_dequeue(&pch->file.rq)))
1933                         kfree_skb(skb);
1934                 wake_up_interruptible(&pch->file.rwait);
1935         } else {
1936                 ppp_do_recv(pch->ppp, skb, pch);
1937         }
1938 
1939 done:
1940         read_unlock_bh(&pch->upl);
1941 }
1942 
1943 /* Put a 0-length skb in the receive queue as an error indication */
1944 void
1945 ppp_input_error(struct ppp_channel *chan, int code)
1946 {
1947         struct channel *pch = chan->ppp;
1948         struct sk_buff *skb;
1949 
1950         if (!pch)
1951                 return;
1952 
1953         read_lock_bh(&pch->upl);
1954         if (pch->ppp) {
1955                 skb = alloc_skb(0, GFP_ATOMIC);
1956                 if (skb) {
1957                         skb->len = 0;           /* probably unnecessary */
1958                         skb->cb[0] = code;
1959                         ppp_do_recv(pch->ppp, skb, pch);
1960                 }
1961         }
1962         read_unlock_bh(&pch->upl);
1963 }
1964 
1965 /*
1966  * We come in here to process a received frame.
1967  * The receive side of the ppp unit is locked.
1968  */
1969 static void
1970 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1971 {
1972         /* note: a 0-length skb is used as an error indication */
1973         if (skb->len > 0) {
1974                 skb_checksum_complete_unset(skb);
1975 #ifdef CONFIG_PPP_MULTILINK
1976                 /* XXX do channel-level decompression here */
1977                 if (PPP_PROTO(skb) == PPP_MP)
1978                         ppp_receive_mp_frame(ppp, skb, pch);
1979                 else
1980 #endif /* CONFIG_PPP_MULTILINK */
1981                         ppp_receive_nonmp_frame(ppp, skb);
1982         } else {
1983                 kfree_skb(skb);
1984                 ppp_receive_error(ppp);
1985         }
1986 }
1987 
1988 static void
1989 ppp_receive_error(struct ppp *ppp)
1990 {
1991         ++ppp->dev->stats.rx_errors;
1992         if (ppp->vj)
1993                 slhc_toss(ppp->vj);
1994 }
1995 
1996 static void
1997 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1998 {
1999         struct sk_buff *ns;
2000         int proto, len, npi;
2001 
2002         /*
2003          * Decompress the frame, if compressed.
2004          * Note that some decompressors need to see uncompressed frames
2005          * that come in as well as compressed frames.
2006          */
2007         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2008             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2009                 skb = ppp_decompress_frame(ppp, skb);
2010 
2011         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2012                 goto err;
2013 
2014         proto = PPP_PROTO(skb);
2015         switch (proto) {
2016         case PPP_VJC_COMP:
2017                 /* decompress VJ compressed packets */
2018                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2019                         goto err;
2020 
2021                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2022                         /* copy to a new sk_buff with more tailroom */
2023                         ns = dev_alloc_skb(skb->len + 128);
2024                         if (!ns) {
2025                                 netdev_err(ppp->dev, "PPP: no memory "
2026                                            "(VJ decomp)\n");
2027                                 goto err;
2028                         }
2029                         skb_reserve(ns, 2);
2030                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2031                         consume_skb(skb);
2032                         skb = ns;
2033                 }
2034                 else
2035                         skb->ip_summed = CHECKSUM_NONE;
2036 
2037                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2038                 if (len <= 0) {
2039                         netdev_printk(KERN_DEBUG, ppp->dev,
2040                                       "PPP: VJ decompression error\n");
2041                         goto err;
2042                 }
2043                 len += 2;
2044                 if (len > skb->len)
2045                         skb_put(skb, len - skb->len);
2046                 else if (len < skb->len)
2047                         skb_trim(skb, len);
2048                 proto = PPP_IP;
2049                 break;
2050 
2051         case PPP_VJC_UNCOMP:
2052                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2053                         goto err;
2054 
2055                 /* Until we fix the decompressor need to make sure
2056                  * data portion is linear.
2057                  */
2058                 if (!pskb_may_pull(skb, skb->len))
2059                         goto err;
2060 
2061                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2062                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2063                         goto err;
2064                 }
2065                 proto = PPP_IP;
2066                 break;
2067 
2068         case PPP_CCP:
2069                 ppp_ccp_peek(ppp, skb, 1);
2070                 break;
2071         }
2072 
2073         ++ppp->stats64.rx_packets;
2074         ppp->stats64.rx_bytes += skb->len - 2;
2075 
2076         npi = proto_to_npindex(proto);
2077         if (npi < 0) {
2078                 /* control or unknown frame - pass it to pppd */
2079                 skb_queue_tail(&ppp->file.rq, skb);
2080                 /* limit queue length by dropping old frames */
2081                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2082                        (skb = skb_dequeue(&ppp->file.rq)))
2083                         kfree_skb(skb);
2084                 /* wake up any process polling or blocking on read */
2085                 wake_up_interruptible(&ppp->file.rwait);
2086 
2087         } else {
2088                 /* network protocol frame - give it to the kernel */
2089 
2090 #ifdef CONFIG_PPP_FILTER
2091                 /* check if the packet passes the pass and active filters */
2092                 /* the filter instructions are constructed assuming
2093                    a four-byte PPP header on each packet */
2094                 if (ppp->pass_filter || ppp->active_filter) {
2095                         if (skb_unclone(skb, GFP_ATOMIC))
2096                                 goto err;
2097 
2098                         *skb_push(skb, 2) = 0;
2099                         if (ppp->pass_filter &&
2100                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2101                                 if (ppp->debug & 1)
2102                                         netdev_printk(KERN_DEBUG, ppp->dev,
2103                                                       "PPP: inbound frame "
2104                                                       "not passed\n");
2105                                 kfree_skb(skb);
2106                                 return;
2107                         }
2108                         if (!(ppp->active_filter &&
2109                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2110                                 ppp->last_recv = jiffies;
2111                         __skb_pull(skb, 2);
2112                 } else
2113 #endif /* CONFIG_PPP_FILTER */
2114                         ppp->last_recv = jiffies;
2115 
2116                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2117                     ppp->npmode[npi] != NPMODE_PASS) {
2118                         kfree_skb(skb);
2119                 } else {
2120                         /* chop off protocol */
2121                         skb_pull_rcsum(skb, 2);
2122                         skb->dev = ppp->dev;
2123                         skb->protocol = htons(npindex_to_ethertype[npi]);
2124                         skb_reset_mac_header(skb);
2125                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2126                                                       dev_net(ppp->dev)));
2127                         netif_rx(skb);
2128                 }
2129         }
2130         return;
2131 
2132  err:
2133         kfree_skb(skb);
2134         ppp_receive_error(ppp);
2135 }
2136 
2137 static struct sk_buff *
2138 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2139 {
2140         int proto = PPP_PROTO(skb);
2141         struct sk_buff *ns;
2142         int len;
2143 
2144         /* Until we fix all the decompressor's need to make sure
2145          * data portion is linear.
2146          */
2147         if (!pskb_may_pull(skb, skb->len))
2148                 goto err;
2149 
2150         if (proto == PPP_COMP) {
2151                 int obuff_size;
2152 
2153                 switch(ppp->rcomp->compress_proto) {
2154                 case CI_MPPE:
2155                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2156                         break;
2157                 default:
2158                         obuff_size = ppp->mru + PPP_HDRLEN;
2159                         break;
2160                 }
2161 
2162                 ns = dev_alloc_skb(obuff_size);
2163                 if (!ns) {
2164                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2165                                    "no memory\n");
2166                         goto err;
2167                 }
2168                 /* the decompressor still expects the A/C bytes in the hdr */
2169                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2170                                 skb->len + 2, ns->data, obuff_size);
2171                 if (len < 0) {
2172                         /* Pass the compressed frame to pppd as an
2173                            error indication. */
2174                         if (len == DECOMP_FATALERROR)
2175                                 ppp->rstate |= SC_DC_FERROR;
2176                         kfree_skb(ns);
2177                         goto err;
2178                 }
2179 
2180                 consume_skb(skb);
2181                 skb = ns;
2182                 skb_put(skb, len);
2183                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2184 
2185         } else {
2186                 /* Uncompressed frame - pass to decompressor so it
2187                    can update its dictionary if necessary. */
2188                 if (ppp->rcomp->incomp)
2189                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2190                                            skb->len + 2);
2191         }
2192 
2193         return skb;
2194 
2195  err:
2196         ppp->rstate |= SC_DC_ERROR;
2197         ppp_receive_error(ppp);
2198         return skb;
2199 }
2200 
2201 #ifdef CONFIG_PPP_MULTILINK
2202 /*
2203  * Receive a multilink frame.
2204  * We put it on the reconstruction queue and then pull off
2205  * as many completed frames as we can.
2206  */
2207 static void
2208 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2209 {
2210         u32 mask, seq;
2211         struct channel *ch;
2212         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2213 
2214         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2215                 goto err;               /* no good, throw it away */
2216 
2217         /* Decode sequence number and begin/end bits */
2218         if (ppp->flags & SC_MP_SHORTSEQ) {
2219                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2220                 mask = 0xfff;
2221         } else {
2222                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2223                 mask = 0xffffff;
2224         }
2225         PPP_MP_CB(skb)->BEbits = skb->data[2];
2226         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2227 
2228         /*
2229          * Do protocol ID decompression on the first fragment of each packet.
2230          */
2231         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2232                 *skb_push(skb, 1) = 0;
2233 
2234         /*
2235          * Expand sequence number to 32 bits, making it as close
2236          * as possible to ppp->minseq.
2237          */
2238         seq |= ppp->minseq & ~mask;
2239         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2240                 seq += mask + 1;
2241         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2242                 seq -= mask + 1;        /* should never happen */
2243         PPP_MP_CB(skb)->sequence = seq;
2244         pch->lastseq = seq;
2245 
2246         /*
2247          * If this packet comes before the next one we were expecting,
2248          * drop it.
2249          */
2250         if (seq_before(seq, ppp->nextseq)) {
2251                 kfree_skb(skb);
2252                 ++ppp->dev->stats.rx_dropped;
2253                 ppp_receive_error(ppp);
2254                 return;
2255         }
2256 
2257         /*
2258          * Reevaluate minseq, the minimum over all channels of the
2259          * last sequence number received on each channel.  Because of
2260          * the increasing sequence number rule, we know that any fragment
2261          * before `minseq' which hasn't arrived is never going to arrive.
2262          * The list of channels can't change because we have the receive
2263          * side of the ppp unit locked.
2264          */
2265         list_for_each_entry(ch, &ppp->channels, clist) {
2266                 if (seq_before(ch->lastseq, seq))
2267                         seq = ch->lastseq;
2268         }
2269         if (seq_before(ppp->minseq, seq))
2270                 ppp->minseq = seq;
2271 
2272         /* Put the fragment on the reconstruction queue */
2273         ppp_mp_insert(ppp, skb);
2274 
2275         /* If the queue is getting long, don't wait any longer for packets
2276            before the start of the queue. */
2277         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2278                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2279                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2280                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2281         }
2282 
2283         /* Pull completed packets off the queue and receive them. */
2284         while ((skb = ppp_mp_reconstruct(ppp))) {
2285                 if (pskb_may_pull(skb, 2))
2286                         ppp_receive_nonmp_frame(ppp, skb);
2287                 else {
2288                         ++ppp->dev->stats.rx_length_errors;
2289                         kfree_skb(skb);
2290                         ppp_receive_error(ppp);
2291                 }
2292         }
2293 
2294         return;
2295 
2296  err:
2297         kfree_skb(skb);
2298         ppp_receive_error(ppp);
2299 }
2300 
2301 /*
2302  * Insert a fragment on the MP reconstruction queue.
2303  * The queue is ordered by increasing sequence number.
2304  */
2305 static void
2306 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2307 {
2308         struct sk_buff *p;
2309         struct sk_buff_head *list = &ppp->mrq;
2310         u32 seq = PPP_MP_CB(skb)->sequence;
2311 
2312         /* N.B. we don't need to lock the list lock because we have the
2313            ppp unit receive-side lock. */
2314         skb_queue_walk(list, p) {
2315                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2316                         break;
2317         }
2318         __skb_queue_before(list, p, skb);
2319 }
2320 
2321 /*
2322  * Reconstruct a packet from the MP fragment queue.
2323  * We go through increasing sequence numbers until we find a
2324  * complete packet, or we get to the sequence number for a fragment
2325  * which hasn't arrived but might still do so.
2326  */
2327 static struct sk_buff *
2328 ppp_mp_reconstruct(struct ppp *ppp)
2329 {
2330         u32 seq = ppp->nextseq;
2331         u32 minseq = ppp->minseq;
2332         struct sk_buff_head *list = &ppp->mrq;
2333         struct sk_buff *p, *tmp;
2334         struct sk_buff *head, *tail;
2335         struct sk_buff *skb = NULL;
2336         int lost = 0, len = 0;
2337 
2338         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2339                 return NULL;
2340         head = list->next;
2341         tail = NULL;
2342         skb_queue_walk_safe(list, p, tmp) {
2343         again:
2344                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2345                         /* this can't happen, anyway ignore the skb */
2346                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2347                                    "seq %u < %u\n",
2348                                    PPP_MP_CB(p)->sequence, seq);
2349                         __skb_unlink(p, list);
2350                         kfree_skb(p);
2351                         continue;
2352                 }
2353                 if (PPP_MP_CB(p)->sequence != seq) {
2354                         u32 oldseq;
2355                         /* Fragment `seq' is missing.  If it is after
2356                            minseq, it might arrive later, so stop here. */
2357                         if (seq_after(seq, minseq))
2358                                 break;
2359                         /* Fragment `seq' is lost, keep going. */
2360                         lost = 1;
2361                         oldseq = seq;
2362                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2363                                 minseq + 1: PPP_MP_CB(p)->sequence;
2364 
2365                         if (ppp->debug & 1)
2366                                 netdev_printk(KERN_DEBUG, ppp->dev,
2367                                               "lost frag %u..%u\n",
2368                                               oldseq, seq-1);
2369 
2370                         goto again;
2371                 }
2372 
2373                 /*
2374                  * At this point we know that all the fragments from
2375                  * ppp->nextseq to seq are either present or lost.
2376                  * Also, there are no complete packets in the queue
2377                  * that have no missing fragments and end before this
2378                  * fragment.
2379                  */
2380 
2381                 /* B bit set indicates this fragment starts a packet */
2382                 if (PPP_MP_CB(p)->BEbits & B) {
2383                         head = p;
2384                         lost = 0;
2385                         len = 0;
2386                 }
2387 
2388                 len += p->len;
2389 
2390                 /* Got a complete packet yet? */
2391                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2392                     (PPP_MP_CB(head)->BEbits & B)) {
2393                         if (len > ppp->mrru + 2) {
2394                                 ++ppp->dev->stats.rx_length_errors;
2395                                 netdev_printk(KERN_DEBUG, ppp->dev,
2396                                               "PPP: reconstructed packet"
2397                                               " is too long (%d)\n", len);
2398                         } else {
2399                                 tail = p;
2400                                 break;
2401                         }
2402                         ppp->nextseq = seq + 1;
2403                 }
2404 
2405                 /*
2406                  * If this is the ending fragment of a packet,
2407                  * and we haven't found a complete valid packet yet,
2408                  * we can discard up to and including this fragment.
2409                  */
2410                 if (PPP_MP_CB(p)->BEbits & E) {
2411                         struct sk_buff *tmp2;
2412 
2413                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2414                                 if (ppp->debug & 1)
2415                                         netdev_printk(KERN_DEBUG, ppp->dev,
2416                                                       "discarding frag %u\n",
2417                                                       PPP_MP_CB(p)->sequence);
2418                                 __skb_unlink(p, list);
2419                                 kfree_skb(p);
2420                         }
2421                         head = skb_peek(list);
2422                         if (!head)
2423                                 break;
2424                 }
2425                 ++seq;
2426         }
2427 
2428         /* If we have a complete packet, copy it all into one skb. */
2429         if (tail != NULL) {
2430                 /* If we have discarded any fragments,
2431                    signal a receive error. */
2432                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2433                         skb_queue_walk_safe(list, p, tmp) {
2434                                 if (p == head)
2435                                         break;
2436                                 if (ppp->debug & 1)
2437                                         netdev_printk(KERN_DEBUG, ppp->dev,
2438                                                       "discarding frag %u\n",
2439                                                       PPP_MP_CB(p)->sequence);
2440                                 __skb_unlink(p, list);
2441                                 kfree_skb(p);
2442                         }
2443 
2444                         if (ppp->debug & 1)
2445                                 netdev_printk(KERN_DEBUG, ppp->dev,
2446                                               "  missed pkts %u..%u\n",
2447                                               ppp->nextseq,
2448                                               PPP_MP_CB(head)->sequence-1);
2449                         ++ppp->dev->stats.rx_dropped;
2450                         ppp_receive_error(ppp);
2451                 }
2452 
2453                 skb = head;
2454                 if (head != tail) {
2455                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2456                         p = skb_queue_next(list, head);
2457                         __skb_unlink(skb, list);
2458                         skb_queue_walk_from_safe(list, p, tmp) {
2459                                 __skb_unlink(p, list);
2460                                 *fragpp = p;
2461                                 p->next = NULL;
2462                                 fragpp = &p->next;
2463 
2464                                 skb->len += p->len;
2465                                 skb->data_len += p->len;
2466                                 skb->truesize += p->truesize;
2467 
2468                                 if (p == tail)
2469                                         break;
2470                         }
2471                 } else {
2472                         __skb_unlink(skb, list);
2473                 }
2474 
2475                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2476         }
2477 
2478         return skb;
2479 }
2480 #endif /* CONFIG_PPP_MULTILINK */
2481 
2482 /*
2483  * Channel interface.
2484  */
2485 
2486 /* Create a new, unattached ppp channel. */
2487 int ppp_register_channel(struct ppp_channel *chan)
2488 {
2489         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2490 }
2491 
2492 /* Create a new, unattached ppp channel for specified net. */
2493 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2494 {
2495         struct channel *pch;
2496         struct ppp_net *pn;
2497 
2498         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2499         if (!pch)
2500                 return -ENOMEM;
2501 
2502         pn = ppp_pernet(net);
2503 
2504         pch->ppp = NULL;
2505         pch->chan = chan;
2506         pch->chan_net = get_net(net);
2507         chan->ppp = pch;
2508         init_ppp_file(&pch->file, CHANNEL);
2509         pch->file.hdrlen = chan->hdrlen;
2510 #ifdef CONFIG_PPP_MULTILINK
2511         pch->lastseq = -1;
2512 #endif /* CONFIG_PPP_MULTILINK */
2513         init_rwsem(&pch->chan_sem);
2514         spin_lock_init(&pch->downl);
2515         rwlock_init(&pch->upl);
2516 
2517         spin_lock_bh(&pn->all_channels_lock);
2518         pch->file.index = ++pn->last_channel_index;
2519         list_add(&pch->list, &pn->new_channels);
2520         atomic_inc(&channel_count);
2521         spin_unlock_bh(&pn->all_channels_lock);
2522 
2523         return 0;
2524 }
2525 
2526 /*
2527  * Return the index of a channel.
2528  */
2529 int ppp_channel_index(struct ppp_channel *chan)
2530 {
2531         struct channel *pch = chan->ppp;
2532 
2533         if (pch)
2534                 return pch->file.index;
2535         return -1;
2536 }
2537 
2538 /*
2539  * Return the PPP unit number to which a channel is connected.
2540  */
2541 int ppp_unit_number(struct ppp_channel *chan)
2542 {
2543         struct channel *pch = chan->ppp;
2544         int unit = -1;
2545 
2546         if (pch) {
2547                 read_lock_bh(&pch->upl);
2548                 if (pch->ppp)
2549                         unit = pch->ppp->file.index;
2550                 read_unlock_bh(&pch->upl);
2551         }
2552         return unit;
2553 }
2554 
2555 /*
2556  * Return the PPP device interface name of a channel.
2557  */
2558 char *ppp_dev_name(struct ppp_channel *chan)
2559 {
2560         struct channel *pch = chan->ppp;
2561         char *name = NULL;
2562 
2563         if (pch) {
2564                 read_lock_bh(&pch->upl);
2565                 if (pch->ppp && pch->ppp->dev)
2566                         name = pch->ppp->dev->name;
2567                 read_unlock_bh(&pch->upl);
2568         }
2569         return name;
2570 }
2571 
2572 
2573 /*
2574  * Disconnect a channel from the generic layer.
2575  * This must be called in process context.
2576  */
2577 void
2578 ppp_unregister_channel(struct ppp_channel *chan)
2579 {
2580         struct channel *pch = chan->ppp;
2581         struct ppp_net *pn;
2582 
2583         if (!pch)
2584                 return;         /* should never happen */
2585 
2586         chan->ppp = NULL;
2587 
2588         /*
2589          * This ensures that we have returned from any calls into the
2590          * the channel's start_xmit or ioctl routine before we proceed.
2591          */
2592         down_write(&pch->chan_sem);
2593         spin_lock_bh(&pch->downl);
2594         pch->chan = NULL;
2595         spin_unlock_bh(&pch->downl);
2596         up_write(&pch->chan_sem);
2597         ppp_disconnect_channel(pch);
2598 
2599         pn = ppp_pernet(pch->chan_net);
2600         spin_lock_bh(&pn->all_channels_lock);
2601         list_del(&pch->list);
2602         spin_unlock_bh(&pn->all_channels_lock);
2603 
2604         pch->file.dead = 1;
2605         wake_up_interruptible(&pch->file.rwait);
2606         if (atomic_dec_and_test(&pch->file.refcnt))
2607                 ppp_destroy_channel(pch);
2608 }
2609 
2610 /*
2611  * Callback from a channel when it can accept more to transmit.
2612  * This should be called at BH/softirq level, not interrupt level.
2613  */
2614 void
2615 ppp_output_wakeup(struct ppp_channel *chan)
2616 {
2617         struct channel *pch = chan->ppp;
2618 
2619         if (!pch)
2620                 return;
2621         ppp_channel_push(pch);
2622 }
2623 
2624 /*
2625  * Compression control.
2626  */
2627 
2628 /* Process the PPPIOCSCOMPRESS ioctl. */
2629 static int
2630 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2631 {
2632         int err;
2633         struct compressor *cp, *ocomp;
2634         struct ppp_option_data data;
2635         void *state, *ostate;
2636         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2637 
2638         err = -EFAULT;
2639         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2640                 goto out;
2641         if (data.length > CCP_MAX_OPTION_LENGTH)
2642                 goto out;
2643         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2644                 goto out;
2645 
2646         err = -EINVAL;
2647         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2648                 goto out;
2649 
2650         cp = try_then_request_module(
2651                 find_compressor(ccp_option[0]),
2652                 "ppp-compress-%d", ccp_option[0]);
2653         if (!cp)
2654                 goto out;
2655 
2656         err = -ENOBUFS;
2657         if (data.transmit) {
2658                 state = cp->comp_alloc(ccp_option, data.length);
2659                 if (state) {
2660                         ppp_xmit_lock(ppp);
2661                         ppp->xstate &= ~SC_COMP_RUN;
2662                         ocomp = ppp->xcomp;
2663                         ostate = ppp->xc_state;
2664                         ppp->xcomp = cp;
2665                         ppp->xc_state = state;
2666                         ppp_xmit_unlock(ppp);
2667                         if (ostate) {
2668                                 ocomp->comp_free(ostate);
2669                                 module_put(ocomp->owner);
2670                         }
2671                         err = 0;
2672                 } else
2673                         module_put(cp->owner);
2674 
2675         } else {
2676                 state = cp->decomp_alloc(ccp_option, data.length);
2677                 if (state) {
2678                         ppp_recv_lock(ppp);
2679                         ppp->rstate &= ~SC_DECOMP_RUN;
2680                         ocomp = ppp->rcomp;
2681                         ostate = ppp->rc_state;
2682                         ppp->rcomp = cp;
2683                         ppp->rc_state = state;
2684                         ppp_recv_unlock(ppp);
2685                         if (ostate) {
2686                                 ocomp->decomp_free(ostate);
2687                                 module_put(ocomp->owner);
2688                         }
2689                         err = 0;
2690                 } else
2691                         module_put(cp->owner);
2692         }
2693 
2694  out:
2695         return err;
2696 }
2697 
2698 /*
2699  * Look at a CCP packet and update our state accordingly.
2700  * We assume the caller has the xmit or recv path locked.
2701  */
2702 static void
2703 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2704 {
2705         unsigned char *dp;
2706         int len;
2707 
2708         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2709                 return; /* no header */
2710         dp = skb->data + 2;
2711 
2712         switch (CCP_CODE(dp)) {
2713         case CCP_CONFREQ:
2714 
2715                 /* A ConfReq starts negotiation of compression
2716                  * in one direction of transmission,
2717                  * and hence brings it down...but which way?
2718                  *
2719                  * Remember:
2720                  * A ConfReq indicates what the sender would like to receive
2721                  */
2722                 if(inbound)
2723                         /* He is proposing what I should send */
2724                         ppp->xstate &= ~SC_COMP_RUN;
2725                 else
2726                         /* I am proposing to what he should send */
2727                         ppp->rstate &= ~SC_DECOMP_RUN;
2728 
2729                 break;
2730 
2731         case CCP_TERMREQ:
2732         case CCP_TERMACK:
2733                 /*
2734                  * CCP is going down, both directions of transmission
2735                  */
2736                 ppp->rstate &= ~SC_DECOMP_RUN;
2737                 ppp->xstate &= ~SC_COMP_RUN;
2738                 break;
2739 
2740         case CCP_CONFACK:
2741                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2742                         break;
2743                 len = CCP_LENGTH(dp);
2744                 if (!pskb_may_pull(skb, len + 2))
2745                         return;         /* too short */
2746                 dp += CCP_HDRLEN;
2747                 len -= CCP_HDRLEN;
2748                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2749                         break;
2750                 if (inbound) {
2751                         /* we will start receiving compressed packets */
2752                         if (!ppp->rc_state)
2753                                 break;
2754                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2755                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2756                                 ppp->rstate |= SC_DECOMP_RUN;
2757                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2758                         }
2759                 } else {
2760                         /* we will soon start sending compressed packets */
2761                         if (!ppp->xc_state)
2762                                 break;
2763                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2764                                         ppp->file.index, 0, ppp->debug))
2765                                 ppp->xstate |= SC_COMP_RUN;
2766                 }
2767                 break;
2768 
2769         case CCP_RESETACK:
2770                 /* reset the [de]compressor */
2771                 if ((ppp->flags & SC_CCP_UP) == 0)
2772                         break;
2773                 if (inbound) {
2774                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2775                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2776                                 ppp->rstate &= ~SC_DC_ERROR;
2777                         }
2778                 } else {
2779                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2780                                 ppp->xcomp->comp_reset(ppp->xc_state);
2781                 }
2782                 break;
2783         }
2784 }
2785 
2786 /* Free up compression resources. */
2787 static void
2788 ppp_ccp_closed(struct ppp *ppp)
2789 {
2790         void *xstate, *rstate;
2791         struct compressor *xcomp, *rcomp;
2792 
2793         ppp_lock(ppp);
2794         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2795         ppp->xstate = 0;
2796         xcomp = ppp->xcomp;
2797         xstate = ppp->xc_state;
2798         ppp->xc_state = NULL;
2799         ppp->rstate = 0;
2800         rcomp = ppp->rcomp;
2801         rstate = ppp->rc_state;
2802         ppp->rc_state = NULL;
2803         ppp_unlock(ppp);
2804 
2805         if (xstate) {
2806                 xcomp->comp_free(xstate);
2807                 module_put(xcomp->owner);
2808         }
2809         if (rstate) {
2810                 rcomp->decomp_free(rstate);
2811                 module_put(rcomp->owner);
2812         }
2813 }
2814 
2815 /* List of compressors. */
2816 static LIST_HEAD(compressor_list);
2817 static DEFINE_SPINLOCK(compressor_list_lock);
2818 
2819 struct compressor_entry {
2820         struct list_head list;
2821         struct compressor *comp;
2822 };
2823 
2824 static struct compressor_entry *
2825 find_comp_entry(int proto)
2826 {
2827         struct compressor_entry *ce;
2828 
2829         list_for_each_entry(ce, &compressor_list, list) {
2830                 if (ce->comp->compress_proto == proto)
2831                         return ce;
2832         }
2833         return NULL;
2834 }
2835 
2836 /* Register a compressor */
2837 int
2838 ppp_register_compressor(struct compressor *cp)
2839 {
2840         struct compressor_entry *ce;
2841         int ret;
2842         spin_lock(&compressor_list_lock);
2843         ret = -EEXIST;
2844         if (find_comp_entry(cp->compress_proto))
2845                 goto out;
2846         ret = -ENOMEM;
2847         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2848         if (!ce)
2849                 goto out;
2850         ret = 0;
2851         ce->comp = cp;
2852         list_add(&ce->list, &compressor_list);
2853  out:
2854         spin_unlock(&compressor_list_lock);
2855         return ret;
2856 }
2857 
2858 /* Unregister a compressor */
2859 void
2860 ppp_unregister_compressor(struct compressor *cp)
2861 {
2862         struct compressor_entry *ce;
2863 
2864         spin_lock(&compressor_list_lock);
2865         ce = find_comp_entry(cp->compress_proto);
2866         if (ce && ce->comp == cp) {
2867                 list_del(&ce->list);
2868                 kfree(ce);
2869         }
2870         spin_unlock(&compressor_list_lock);
2871 }
2872 
2873 /* Find a compressor. */
2874 static struct compressor *
2875 find_compressor(int type)
2876 {
2877         struct compressor_entry *ce;
2878         struct compressor *cp = NULL;
2879 
2880         spin_lock(&compressor_list_lock);
2881         ce = find_comp_entry(type);
2882         if (ce) {
2883                 cp = ce->comp;
2884                 if (!try_module_get(cp->owner))
2885                         cp = NULL;
2886         }
2887         spin_unlock(&compressor_list_lock);
2888         return cp;
2889 }
2890 
2891 /*
2892  * Miscelleneous stuff.
2893  */
2894 
2895 static void
2896 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2897 {
2898         struct slcompress *vj = ppp->vj;
2899 
2900         memset(st, 0, sizeof(*st));
2901         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2902         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2903         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2904         st->p.ppp_opackets = ppp->stats64.tx_packets;
2905         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2906         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2907         if (!vj)
2908                 return;
2909         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2910         st->vj.vjs_compressed = vj->sls_o_compressed;
2911         st->vj.vjs_searches = vj->sls_o_searches;
2912         st->vj.vjs_misses = vj->sls_o_misses;
2913         st->vj.vjs_errorin = vj->sls_i_error;
2914         st->vj.vjs_tossed = vj->sls_i_tossed;
2915         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2916         st->vj.vjs_compressedin = vj->sls_i_compressed;
2917 }
2918 
2919 /*
2920  * Stuff for handling the lists of ppp units and channels
2921  * and for initialization.
2922  */
2923 
2924 /*
2925  * Create a new ppp interface unit.  Fails if it can't allocate memory
2926  * or if there is already a unit with the requested number.
2927  * unit == -1 means allocate a new number.
2928  */
2929 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
2930 {
2931         struct ppp_config conf = {
2932                 .file = file,
2933                 .unit = *unit,
2934                 .ifname_is_set = false,
2935         };
2936         struct net_device *dev;
2937         struct ppp *ppp;
2938         int err;
2939 
2940         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
2941         if (!dev) {
2942                 err = -ENOMEM;
2943                 goto err;
2944         }
2945         dev_net_set(dev, net);
2946         dev->rtnl_link_ops = &ppp_link_ops;
2947 
2948         rtnl_lock();
2949 
2950         err = ppp_dev_configure(net, dev, &conf);
2951         if (err < 0)
2952                 goto err_dev;
2953         ppp = netdev_priv(dev);
2954         *unit = ppp->file.index;
2955 
2956         rtnl_unlock();
2957 
2958         return 0;
2959 
2960 err_dev:
2961         rtnl_unlock();
2962         free_netdev(dev);
2963 err:
2964         return err;
2965 }
2966 
2967 /*
2968  * Initialize a ppp_file structure.
2969  */
2970 static void
2971 init_ppp_file(struct ppp_file *pf, int kind)
2972 {
2973         pf->kind = kind;
2974         skb_queue_head_init(&pf->xq);
2975         skb_queue_head_init(&pf->rq);
2976         atomic_set(&pf->refcnt, 1);
2977         init_waitqueue_head(&pf->rwait);
2978 }
2979 
2980 /*
2981  * Free the memory used by a ppp unit.  This is only called once
2982  * there are no channels connected to the unit and no file structs
2983  * that reference the unit.
2984  */
2985 static void ppp_destroy_interface(struct ppp *ppp)
2986 {
2987         atomic_dec(&ppp_unit_count);
2988 
2989         if (!ppp->file.dead || ppp->n_channels) {
2990                 /* "can't happen" */
2991                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2992                            "but dead=%d n_channels=%d !\n",
2993                            ppp, ppp->file.dead, ppp->n_channels);
2994                 return;
2995         }
2996 
2997         ppp_ccp_closed(ppp);
2998         if (ppp->vj) {
2999                 slhc_free(ppp->vj);
3000                 ppp->vj = NULL;
3001         }
3002         skb_queue_purge(&ppp->file.xq);
3003         skb_queue_purge(&ppp->file.rq);
3004 #ifdef CONFIG_PPP_MULTILINK
3005         skb_queue_purge(&ppp->mrq);
3006 #endif /* CONFIG_PPP_MULTILINK */
3007 #ifdef CONFIG_PPP_FILTER
3008         if (ppp->pass_filter) {
3009                 bpf_prog_destroy(ppp->pass_filter);
3010                 ppp->pass_filter = NULL;
3011         }
3012 
3013         if (ppp->active_filter) {
3014                 bpf_prog_destroy(ppp->active_filter);
3015                 ppp->active_filter = NULL;
3016         }
3017 #endif /* CONFIG_PPP_FILTER */
3018 
3019         kfree_skb(ppp->xmit_pending);
3020 
3021         free_netdev(ppp->dev);
3022 }
3023 
3024 /*
3025  * Locate an existing ppp unit.
3026  * The caller should have locked the all_ppp_mutex.
3027  */
3028 static struct ppp *
3029 ppp_find_unit(struct ppp_net *pn, int unit)
3030 {
3031         return unit_find(&pn->units_idr, unit);
3032 }
3033 
3034 /*
3035  * Locate an existing ppp channel.
3036  * The caller should have locked the all_channels_lock.
3037  * First we look in the new_channels list, then in the
3038  * all_channels list.  If found in the new_channels list,
3039  * we move it to the all_channels list.  This is for speed
3040  * when we have a lot of channels in use.
3041  */
3042 static struct channel *
3043 ppp_find_channel(struct ppp_net *pn, int unit)
3044 {
3045         struct channel *pch;
3046 
3047         list_for_each_entry(pch, &pn->new_channels, list) {
3048                 if (pch->file.index == unit) {
3049                         list_move(&pch->list, &pn->all_channels);
3050                         return pch;
3051                 }
3052         }
3053 
3054         list_for_each_entry(pch, &pn->all_channels, list) {
3055                 if (pch->file.index == unit)
3056                         return pch;
3057         }
3058 
3059         return NULL;
3060 }
3061 
3062 /*
3063  * Connect a PPP channel to a PPP interface unit.
3064  */
3065 static int
3066 ppp_connect_channel(struct channel *pch, int unit)
3067 {
3068         struct ppp *ppp;
3069         struct ppp_net *pn;
3070         int ret = -ENXIO;
3071         int hdrlen;
3072 
3073         pn = ppp_pernet(pch->chan_net);
3074 
3075         mutex_lock(&pn->all_ppp_mutex);
3076         ppp = ppp_find_unit(pn, unit);
3077         if (!ppp)
3078                 goto out;
3079         write_lock_bh(&pch->upl);
3080         ret = -EINVAL;
3081         if (pch->ppp)
3082                 goto outl;
3083 
3084         ppp_lock(ppp);
3085         if (pch->file.hdrlen > ppp->file.hdrlen)
3086                 ppp->file.hdrlen = pch->file.hdrlen;
3087         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3088         if (hdrlen > ppp->dev->hard_header_len)
3089                 ppp->dev->hard_header_len = hdrlen;
3090         list_add_tail(&pch->clist, &ppp->channels);
3091         ++ppp->n_channels;
3092         pch->ppp = ppp;
3093         atomic_inc(&ppp->file.refcnt);
3094         ppp_unlock(ppp);
3095         ret = 0;
3096 
3097  outl:
3098         write_unlock_bh(&pch->upl);
3099  out:
3100         mutex_unlock(&pn->all_ppp_mutex);
3101         return ret;
3102 }
3103 
3104 /*
3105  * Disconnect a channel from its ppp unit.
3106  */
3107 static int
3108 ppp_disconnect_channel(struct channel *pch)
3109 {
3110         struct ppp *ppp;
3111         int err = -EINVAL;
3112 
3113         write_lock_bh(&pch->upl);
3114         ppp = pch->ppp;
3115         pch->ppp = NULL;
3116         write_unlock_bh(&pch->upl);
3117         if (ppp) {
3118                 /* remove it from the ppp unit's list */
3119                 ppp_lock(ppp);
3120                 list_del(&pch->clist);
3121                 if (--ppp->n_channels == 0)
3122                         wake_up_interruptible(&ppp->file.rwait);
3123                 ppp_unlock(ppp);
3124                 if (atomic_dec_and_test(&ppp->file.refcnt))
3125                         ppp_destroy_interface(ppp);
3126                 err = 0;
3127         }
3128         return err;
3129 }
3130 
3131 /*
3132  * Free up the resources used by a ppp channel.
3133  */
3134 static void ppp_destroy_channel(struct channel *pch)
3135 {
3136         put_net(pch->chan_net);
3137         pch->chan_net = NULL;
3138 
3139         atomic_dec(&channel_count);
3140 
3141         if (!pch->file.dead) {
3142                 /* "can't happen" */
3143                 pr_err("ppp: destroying undead channel %p !\n", pch);
3144                 return;
3145         }
3146         skb_queue_purge(&pch->file.xq);
3147         skb_queue_purge(&pch->file.rq);
3148         kfree(pch);
3149 }
3150 
3151 static void __exit ppp_cleanup(void)
3152 {
3153         /* should never happen */
3154         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3155                 pr_err("PPP: removing module but units remain!\n");
3156         rtnl_link_unregister(&ppp_link_ops);
3157         unregister_chrdev(PPP_MAJOR, "ppp");
3158         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3159         class_destroy(ppp_class);
3160         unregister_pernet_device(&ppp_net_ops);
3161 }
3162 
3163 /*
3164  * Units handling. Caller must protect concurrent access
3165  * by holding all_ppp_mutex
3166  */
3167 
3168 /* associate pointer with specified number */
3169 static int unit_set(struct idr *p, void *ptr, int n)
3170 {
3171         int unit;
3172 
3173         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3174         if (unit == -ENOSPC)
3175                 unit = -EINVAL;
3176         return unit;
3177 }
3178 
3179 /* get new free unit number and associate pointer with it */
3180 static int unit_get(struct idr *p, void *ptr)
3181 {
3182         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3183 }
3184 
3185 /* put unit number back to a pool */
3186 static void unit_put(struct idr *p, int n)
3187 {
3188         idr_remove(p, n);
3189 }
3190 
3191 /* get pointer associated with the number */
3192 static void *unit_find(struct idr *p, int n)
3193 {
3194         return idr_find(p, n);
3195 }
3196 
3197 /* Module/initialization stuff */
3198 
3199 module_init(ppp_init);
3200 module_exit(ppp_cleanup);
3201 
3202 EXPORT_SYMBOL(ppp_register_net_channel);
3203 EXPORT_SYMBOL(ppp_register_channel);
3204 EXPORT_SYMBOL(ppp_unregister_channel);
3205 EXPORT_SYMBOL(ppp_channel_index);
3206 EXPORT_SYMBOL(ppp_unit_number);
3207 EXPORT_SYMBOL(ppp_dev_name);
3208 EXPORT_SYMBOL(ppp_input);
3209 EXPORT_SYMBOL(ppp_input_error);
3210 EXPORT_SYMBOL(ppp_output_wakeup);
3211 EXPORT_SYMBOL(ppp_register_compressor);
3212 EXPORT_SYMBOL(ppp_unregister_compressor);
3213 MODULE_LICENSE("GPL");
3214 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3215 MODULE_ALIAS_RTNL_LINK("ppp");
3216 MODULE_ALIAS("devname:ppp");
3217 

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