Version:  2.0.40 2.2.26 2.4.37 3.8 3.9 3.10 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

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 <asm/unaligned.h>
 50 #include <net/slhc_vj.h>
 51 #include <linux/atomic.h>
 52 
 53 #include <linux/nsproxy.h>
 54 #include <net/net_namespace.h>
 55 #include <net/netns/generic.h>
 56 
 57 #define PPP_VERSION     "2.4.2"
 58 
 59 /*
 60  * Network protocols we support.
 61  */
 62 #define NP_IP   0               /* Internet Protocol V4 */
 63 #define NP_IPV6 1               /* Internet Protocol V6 */
 64 #define NP_IPX  2               /* IPX protocol */
 65 #define NP_AT   3               /* Appletalk protocol */
 66 #define NP_MPLS_UC 4            /* MPLS unicast */
 67 #define NP_MPLS_MC 5            /* MPLS multicast */
 68 #define NUM_NP  6               /* Number of NPs. */
 69 
 70 #define MPHDRLEN        6       /* multilink protocol header length */
 71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
 72 
 73 /*
 74  * An instance of /dev/ppp can be associated with either a ppp
 75  * interface unit or a ppp channel.  In both cases, file->private_data
 76  * points to one of these.
 77  */
 78 struct ppp_file {
 79         enum {
 80                 INTERFACE=1, CHANNEL
 81         }               kind;
 82         struct sk_buff_head xq;         /* pppd transmit queue */
 83         struct sk_buff_head rq;         /* receive queue for pppd */
 84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
 85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
 86         int             hdrlen;         /* space to leave for headers */
 87         int             index;          /* interface unit / channel number */
 88         int             dead;           /* unit/channel has been shut down */
 89 };
 90 
 91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
 92 
 93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
 94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
 95 
 96 /*
 97  * Data structure to hold primary network stats for which
 98  * we want to use 64 bit storage.  Other network stats
 99  * are stored in dev->stats of the ppp strucute.
100  */
101 struct ppp_link_stats {
102         u64 rx_packets;
103         u64 tx_packets;
104         u64 rx_bytes;
105         u64 tx_bytes;
106 };
107 
108 /*
109  * Data structure describing one ppp unit.
110  * A ppp unit corresponds to a ppp network interface device
111  * and represents a multilink bundle.
112  * It can have 0 or more ppp channels connected to it.
113  */
114 struct ppp {
115         struct ppp_file file;           /* stuff for read/write/poll 0 */
116         struct file     *owner;         /* file that owns this unit 48 */
117         struct list_head channels;      /* list of attached channels 4c */
118         int             n_channels;     /* how many channels are attached 54 */
119         spinlock_t      rlock;          /* lock for receive side 58 */
120         spinlock_t      wlock;          /* lock for transmit side 5c */
121         int             mru;            /* max receive unit 60 */
122         unsigned int    flags;          /* control bits 64 */
123         unsigned int    xstate;         /* transmit state bits 68 */
124         unsigned int    rstate;         /* receive state bits 6c */
125         int             debug;          /* debug flags 70 */
126         struct slcompress *vj;          /* state for VJ header compression */
127         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
128         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
129         struct compressor *xcomp;       /* transmit packet compressor 8c */
130         void            *xc_state;      /* its internal state 90 */
131         struct compressor *rcomp;       /* receive decompressor 94 */
132         void            *rc_state;      /* its internal state 98 */
133         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
134         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
135         struct net_device *dev;         /* network interface device a4 */
136         int             closing;        /* is device closing down? a8 */
137 #ifdef CONFIG_PPP_MULTILINK
138         int             nxchan;         /* next channel to send something on */
139         u32             nxseq;          /* next sequence number to send */
140         int             mrru;           /* MP: max reconst. receive unit */
141         u32             nextseq;        /* MP: seq no of next packet */
142         u32             minseq;         /* MP: min of most recent seqnos */
143         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
144 #endif /* CONFIG_PPP_MULTILINK */
145 #ifdef CONFIG_PPP_FILTER
146         struct bpf_prog *pass_filter;   /* filter for packets to pass */
147         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
148 #endif /* CONFIG_PPP_FILTER */
149         struct net      *ppp_net;       /* the net we belong to */
150         struct ppp_link_stats stats64;  /* 64 bit network stats */
151 };
152 
153 /*
154  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
155  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
156  * SC_MUST_COMP
157  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
158  * Bits in xstate: SC_COMP_RUN
159  */
160 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
161                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
162                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
163 
164 /*
165  * Private data structure for each channel.
166  * This includes the data structure used for multilink.
167  */
168 struct channel {
169         struct ppp_file file;           /* stuff for read/write/poll */
170         struct list_head list;          /* link in all/new_channels list */
171         struct ppp_channel *chan;       /* public channel data structure */
172         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
173         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
174         struct ppp      *ppp;           /* ppp unit we're connected to */
175         struct net      *chan_net;      /* the net channel belongs to */
176         struct list_head clist;         /* link in list of channels per unit */
177         rwlock_t        upl;            /* protects `ppp' */
178 #ifdef CONFIG_PPP_MULTILINK
179         u8              avail;          /* flag used in multilink stuff */
180         u8              had_frag;       /* >= 1 fragments have been sent */
181         u32             lastseq;        /* MP: last sequence # received */
182         int             speed;          /* speed of the corresponding ppp channel*/
183 #endif /* CONFIG_PPP_MULTILINK */
184 };
185 
186 /*
187  * SMP locking issues:
188  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
189  * list and the ppp.n_channels field, you need to take both locks
190  * before you modify them.
191  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
192  * channel.downl.
193  */
194 
195 static DEFINE_MUTEX(ppp_mutex);
196 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
197 static atomic_t channel_count = ATOMIC_INIT(0);
198 
199 /* per-net private data for this module */
200 static int ppp_net_id __read_mostly;
201 struct ppp_net {
202         /* units to ppp mapping */
203         struct idr units_idr;
204 
205         /*
206          * all_ppp_mutex protects the units_idr mapping.
207          * It also ensures that finding a ppp unit in the units_idr
208          * map and updating its file.refcnt field is atomic.
209          */
210         struct mutex all_ppp_mutex;
211 
212         /* channels */
213         struct list_head all_channels;
214         struct list_head new_channels;
215         int last_channel_index;
216 
217         /*
218          * all_channels_lock protects all_channels and
219          * last_channel_index, and the atomicity of find
220          * a channel and updating its file.refcnt field.
221          */
222         spinlock_t all_channels_lock;
223 };
224 
225 /* Get the PPP protocol number from a skb */
226 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
227 
228 /* We limit the length of ppp->file.rq to this (arbitrary) value */
229 #define PPP_MAX_RQLEN   32
230 
231 /*
232  * Maximum number of multilink fragments queued up.
233  * This has to be large enough to cope with the maximum latency of
234  * the slowest channel relative to the others.  Strictly it should
235  * depend on the number of channels and their characteristics.
236  */
237 #define PPP_MP_MAX_QLEN 128
238 
239 /* Multilink header bits. */
240 #define B       0x80            /* this fragment begins a packet */
241 #define E       0x40            /* this fragment ends a packet */
242 
243 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
244 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
245 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
246 
247 /* Prototypes. */
248 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
249                         struct file *file, unsigned int cmd, unsigned long arg);
250 static void ppp_xmit_process(struct ppp *ppp);
251 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
252 static void ppp_push(struct ppp *ppp);
253 static void ppp_channel_push(struct channel *pch);
254 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
255                               struct channel *pch);
256 static void ppp_receive_error(struct ppp *ppp);
257 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
258 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
259                                             struct sk_buff *skb);
260 #ifdef CONFIG_PPP_MULTILINK
261 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
262                                 struct channel *pch);
263 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
264 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
265 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
266 #endif /* CONFIG_PPP_MULTILINK */
267 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
268 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
269 static void ppp_ccp_closed(struct ppp *ppp);
270 static struct compressor *find_compressor(int type);
271 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
272 static struct ppp *ppp_create_interface(struct net *net, int unit,
273                                         struct file *file, int *retp);
274 static void init_ppp_file(struct ppp_file *pf, int kind);
275 static void ppp_destroy_interface(struct ppp *ppp);
276 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
277 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
278 static int ppp_connect_channel(struct channel *pch, int unit);
279 static int ppp_disconnect_channel(struct channel *pch);
280 static void ppp_destroy_channel(struct channel *pch);
281 static int unit_get(struct idr *p, void *ptr);
282 static int unit_set(struct idr *p, void *ptr, int n);
283 static void unit_put(struct idr *p, int n);
284 static void *unit_find(struct idr *p, int n);
285 
286 static const struct net_device_ops ppp_netdev_ops;
287 
288 static struct class *ppp_class;
289 
290 /* per net-namespace data */
291 static inline struct ppp_net *ppp_pernet(struct net *net)
292 {
293         BUG_ON(!net);
294 
295         return net_generic(net, ppp_net_id);
296 }
297 
298 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
299 static inline int proto_to_npindex(int proto)
300 {
301         switch (proto) {
302         case PPP_IP:
303                 return NP_IP;
304         case PPP_IPV6:
305                 return NP_IPV6;
306         case PPP_IPX:
307                 return NP_IPX;
308         case PPP_AT:
309                 return NP_AT;
310         case PPP_MPLS_UC:
311                 return NP_MPLS_UC;
312         case PPP_MPLS_MC:
313                 return NP_MPLS_MC;
314         }
315         return -EINVAL;
316 }
317 
318 /* Translates an NP index into a PPP protocol number */
319 static const int npindex_to_proto[NUM_NP] = {
320         PPP_IP,
321         PPP_IPV6,
322         PPP_IPX,
323         PPP_AT,
324         PPP_MPLS_UC,
325         PPP_MPLS_MC,
326 };
327 
328 /* Translates an ethertype into an NP index */
329 static inline int ethertype_to_npindex(int ethertype)
330 {
331         switch (ethertype) {
332         case ETH_P_IP:
333                 return NP_IP;
334         case ETH_P_IPV6:
335                 return NP_IPV6;
336         case ETH_P_IPX:
337                 return NP_IPX;
338         case ETH_P_PPPTALK:
339         case ETH_P_ATALK:
340                 return NP_AT;
341         case ETH_P_MPLS_UC:
342                 return NP_MPLS_UC;
343         case ETH_P_MPLS_MC:
344                 return NP_MPLS_MC;
345         }
346         return -1;
347 }
348 
349 /* Translates an NP index into an ethertype */
350 static const int npindex_to_ethertype[NUM_NP] = {
351         ETH_P_IP,
352         ETH_P_IPV6,
353         ETH_P_IPX,
354         ETH_P_PPPTALK,
355         ETH_P_MPLS_UC,
356         ETH_P_MPLS_MC,
357 };
358 
359 /*
360  * Locking shorthand.
361  */
362 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
363 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
364 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
365 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
366 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
367                                      ppp_recv_lock(ppp); } while (0)
368 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
369                                      ppp_xmit_unlock(ppp); } while (0)
370 
371 /*
372  * /dev/ppp device routines.
373  * The /dev/ppp device is used by pppd to control the ppp unit.
374  * It supports the read, write, ioctl and poll functions.
375  * Open instances of /dev/ppp can be in one of three states:
376  * unattached, attached to a ppp unit, or attached to a ppp channel.
377  */
378 static int ppp_open(struct inode *inode, struct file *file)
379 {
380         /*
381          * This could (should?) be enforced by the permissions on /dev/ppp.
382          */
383         if (!capable(CAP_NET_ADMIN))
384                 return -EPERM;
385         return 0;
386 }
387 
388 static int ppp_release(struct inode *unused, struct file *file)
389 {
390         struct ppp_file *pf = file->private_data;
391         struct ppp *ppp;
392 
393         if (pf) {
394                 file->private_data = NULL;
395                 if (pf->kind == INTERFACE) {
396                         ppp = PF_TO_PPP(pf);
397                         rtnl_lock();
398                         if (file == ppp->owner)
399                                 unregister_netdevice(ppp->dev);
400                         rtnl_unlock();
401                 }
402                 if (atomic_dec_and_test(&pf->refcnt)) {
403                         switch (pf->kind) {
404                         case INTERFACE:
405                                 ppp_destroy_interface(PF_TO_PPP(pf));
406                                 break;
407                         case CHANNEL:
408                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
409                                 break;
410                         }
411                 }
412         }
413         return 0;
414 }
415 
416 static ssize_t ppp_read(struct file *file, char __user *buf,
417                         size_t count, loff_t *ppos)
418 {
419         struct ppp_file *pf = file->private_data;
420         DECLARE_WAITQUEUE(wait, current);
421         ssize_t ret;
422         struct sk_buff *skb = NULL;
423         struct iovec iov;
424         struct iov_iter to;
425 
426         ret = count;
427 
428         if (!pf)
429                 return -ENXIO;
430         add_wait_queue(&pf->rwait, &wait);
431         for (;;) {
432                 set_current_state(TASK_INTERRUPTIBLE);
433                 skb = skb_dequeue(&pf->rq);
434                 if (skb)
435                         break;
436                 ret = 0;
437                 if (pf->dead)
438                         break;
439                 if (pf->kind == INTERFACE) {
440                         /*
441                          * Return 0 (EOF) on an interface that has no
442                          * channels connected, unless it is looping
443                          * network traffic (demand mode).
444                          */
445                         struct ppp *ppp = PF_TO_PPP(pf);
446                         if (ppp->n_channels == 0 &&
447                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
448                                 break;
449                 }
450                 ret = -EAGAIN;
451                 if (file->f_flags & O_NONBLOCK)
452                         break;
453                 ret = -ERESTARTSYS;
454                 if (signal_pending(current))
455                         break;
456                 schedule();
457         }
458         set_current_state(TASK_RUNNING);
459         remove_wait_queue(&pf->rwait, &wait);
460 
461         if (!skb)
462                 goto out;
463 
464         ret = -EOVERFLOW;
465         if (skb->len > count)
466                 goto outf;
467         ret = -EFAULT;
468         iov.iov_base = buf;
469         iov.iov_len = count;
470         iov_iter_init(&to, READ, &iov, 1, count);
471         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
472                 goto outf;
473         ret = skb->len;
474 
475  outf:
476         kfree_skb(skb);
477  out:
478         return ret;
479 }
480 
481 static ssize_t ppp_write(struct file *file, const char __user *buf,
482                          size_t count, loff_t *ppos)
483 {
484         struct ppp_file *pf = file->private_data;
485         struct sk_buff *skb;
486         ssize_t ret;
487 
488         if (!pf)
489                 return -ENXIO;
490         ret = -ENOMEM;
491         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
492         if (!skb)
493                 goto out;
494         skb_reserve(skb, pf->hdrlen);
495         ret = -EFAULT;
496         if (copy_from_user(skb_put(skb, count), buf, count)) {
497                 kfree_skb(skb);
498                 goto out;
499         }
500 
501         skb_queue_tail(&pf->xq, skb);
502 
503         switch (pf->kind) {
504         case INTERFACE:
505                 ppp_xmit_process(PF_TO_PPP(pf));
506                 break;
507         case CHANNEL:
508                 ppp_channel_push(PF_TO_CHANNEL(pf));
509                 break;
510         }
511 
512         ret = count;
513 
514  out:
515         return ret;
516 }
517 
518 /* No kernel lock - fine */
519 static unsigned int ppp_poll(struct file *file, poll_table *wait)
520 {
521         struct ppp_file *pf = file->private_data;
522         unsigned int mask;
523 
524         if (!pf)
525                 return 0;
526         poll_wait(file, &pf->rwait, wait);
527         mask = POLLOUT | POLLWRNORM;
528         if (skb_peek(&pf->rq))
529                 mask |= POLLIN | POLLRDNORM;
530         if (pf->dead)
531                 mask |= POLLHUP;
532         else if (pf->kind == INTERFACE) {
533                 /* see comment in ppp_read */
534                 struct ppp *ppp = PF_TO_PPP(pf);
535                 if (ppp->n_channels == 0 &&
536                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
537                         mask |= POLLIN | POLLRDNORM;
538         }
539 
540         return mask;
541 }
542 
543 #ifdef CONFIG_PPP_FILTER
544 static int get_filter(void __user *arg, struct sock_filter **p)
545 {
546         struct sock_fprog uprog;
547         struct sock_filter *code = NULL;
548         int len;
549 
550         if (copy_from_user(&uprog, arg, sizeof(uprog)))
551                 return -EFAULT;
552 
553         if (!uprog.len) {
554                 *p = NULL;
555                 return 0;
556         }
557 
558         len = uprog.len * sizeof(struct sock_filter);
559         code = memdup_user(uprog.filter, len);
560         if (IS_ERR(code))
561                 return PTR_ERR(code);
562 
563         *p = code;
564         return uprog.len;
565 }
566 #endif /* CONFIG_PPP_FILTER */
567 
568 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
569 {
570         struct ppp_file *pf = file->private_data;
571         struct ppp *ppp;
572         int err = -EFAULT, val, val2, i;
573         struct ppp_idle idle;
574         struct npioctl npi;
575         int unit, cflags;
576         struct slcompress *vj;
577         void __user *argp = (void __user *)arg;
578         int __user *p = argp;
579 
580         if (!pf)
581                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
582                                         pf, file, cmd, arg);
583 
584         if (cmd == PPPIOCDETACH) {
585                 /*
586                  * We have to be careful here... if the file descriptor
587                  * has been dup'd, we could have another process in the
588                  * middle of a poll using the same file *, so we had
589                  * better not free the interface data structures -
590                  * instead we fail the ioctl.  Even in this case, we
591                  * shut down the interface if we are the owner of it.
592                  * Actually, we should get rid of PPPIOCDETACH, userland
593                  * (i.e. pppd) could achieve the same effect by closing
594                  * this fd and reopening /dev/ppp.
595                  */
596                 err = -EINVAL;
597                 mutex_lock(&ppp_mutex);
598                 if (pf->kind == INTERFACE) {
599                         ppp = PF_TO_PPP(pf);
600                         rtnl_lock();
601                         if (file == ppp->owner)
602                                 unregister_netdevice(ppp->dev);
603                         rtnl_unlock();
604                 }
605                 if (atomic_long_read(&file->f_count) < 2) {
606                         ppp_release(NULL, file);
607                         err = 0;
608                 } else
609                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
610                                 atomic_long_read(&file->f_count));
611                 mutex_unlock(&ppp_mutex);
612                 return err;
613         }
614 
615         if (pf->kind == CHANNEL) {
616                 struct channel *pch;
617                 struct ppp_channel *chan;
618 
619                 mutex_lock(&ppp_mutex);
620                 pch = PF_TO_CHANNEL(pf);
621 
622                 switch (cmd) {
623                 case PPPIOCCONNECT:
624                         if (get_user(unit, p))
625                                 break;
626                         err = ppp_connect_channel(pch, unit);
627                         break;
628 
629                 case PPPIOCDISCONN:
630                         err = ppp_disconnect_channel(pch);
631                         break;
632 
633                 default:
634                         down_read(&pch->chan_sem);
635                         chan = pch->chan;
636                         err = -ENOTTY;
637                         if (chan && chan->ops->ioctl)
638                                 err = chan->ops->ioctl(chan, cmd, arg);
639                         up_read(&pch->chan_sem);
640                 }
641                 mutex_unlock(&ppp_mutex);
642                 return err;
643         }
644 
645         if (pf->kind != INTERFACE) {
646                 /* can't happen */
647                 pr_err("PPP: not interface or channel??\n");
648                 return -EINVAL;
649         }
650 
651         mutex_lock(&ppp_mutex);
652         ppp = PF_TO_PPP(pf);
653         switch (cmd) {
654         case PPPIOCSMRU:
655                 if (get_user(val, p))
656                         break;
657                 ppp->mru = val;
658                 err = 0;
659                 break;
660 
661         case PPPIOCSFLAGS:
662                 if (get_user(val, p))
663                         break;
664                 ppp_lock(ppp);
665                 cflags = ppp->flags & ~val;
666 #ifdef CONFIG_PPP_MULTILINK
667                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
668                         ppp->nextseq = 0;
669 #endif
670                 ppp->flags = val & SC_FLAG_BITS;
671                 ppp_unlock(ppp);
672                 if (cflags & SC_CCP_OPEN)
673                         ppp_ccp_closed(ppp);
674                 err = 0;
675                 break;
676 
677         case PPPIOCGFLAGS:
678                 val = ppp->flags | ppp->xstate | ppp->rstate;
679                 if (put_user(val, p))
680                         break;
681                 err = 0;
682                 break;
683 
684         case PPPIOCSCOMPRESS:
685                 err = ppp_set_compress(ppp, arg);
686                 break;
687 
688         case PPPIOCGUNIT:
689                 if (put_user(ppp->file.index, p))
690                         break;
691                 err = 0;
692                 break;
693 
694         case PPPIOCSDEBUG:
695                 if (get_user(val, p))
696                         break;
697                 ppp->debug = val;
698                 err = 0;
699                 break;
700 
701         case PPPIOCGDEBUG:
702                 if (put_user(ppp->debug, p))
703                         break;
704                 err = 0;
705                 break;
706 
707         case PPPIOCGIDLE:
708                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
709                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
710                 if (copy_to_user(argp, &idle, sizeof(idle)))
711                         break;
712                 err = 0;
713                 break;
714 
715         case PPPIOCSMAXCID:
716                 if (get_user(val, p))
717                         break;
718                 val2 = 15;
719                 if ((val >> 16) != 0) {
720                         val2 = val >> 16;
721                         val &= 0xffff;
722                 }
723                 vj = slhc_init(val2+1, val+1);
724                 if (IS_ERR(vj)) {
725                         err = PTR_ERR(vj);
726                         break;
727                 }
728                 ppp_lock(ppp);
729                 if (ppp->vj)
730                         slhc_free(ppp->vj);
731                 ppp->vj = vj;
732                 ppp_unlock(ppp);
733                 err = 0;
734                 break;
735 
736         case PPPIOCGNPMODE:
737         case PPPIOCSNPMODE:
738                 if (copy_from_user(&npi, argp, sizeof(npi)))
739                         break;
740                 err = proto_to_npindex(npi.protocol);
741                 if (err < 0)
742                         break;
743                 i = err;
744                 if (cmd == PPPIOCGNPMODE) {
745                         err = -EFAULT;
746                         npi.mode = ppp->npmode[i];
747                         if (copy_to_user(argp, &npi, sizeof(npi)))
748                                 break;
749                 } else {
750                         ppp->npmode[i] = npi.mode;
751                         /* we may be able to transmit more packets now (??) */
752                         netif_wake_queue(ppp->dev);
753                 }
754                 err = 0;
755                 break;
756 
757 #ifdef CONFIG_PPP_FILTER
758         case PPPIOCSPASS:
759         {
760                 struct sock_filter *code;
761 
762                 err = get_filter(argp, &code);
763                 if (err >= 0) {
764                         struct bpf_prog *pass_filter = NULL;
765                         struct sock_fprog_kern fprog = {
766                                 .len = err,
767                                 .filter = code,
768                         };
769 
770                         err = 0;
771                         if (fprog.filter)
772                                 err = bpf_prog_create(&pass_filter, &fprog);
773                         if (!err) {
774                                 ppp_lock(ppp);
775                                 if (ppp->pass_filter)
776                                         bpf_prog_destroy(ppp->pass_filter);
777                                 ppp->pass_filter = pass_filter;
778                                 ppp_unlock(ppp);
779                         }
780                         kfree(code);
781                 }
782                 break;
783         }
784         case PPPIOCSACTIVE:
785         {
786                 struct sock_filter *code;
787 
788                 err = get_filter(argp, &code);
789                 if (err >= 0) {
790                         struct bpf_prog *active_filter = NULL;
791                         struct sock_fprog_kern fprog = {
792                                 .len = err,
793                                 .filter = code,
794                         };
795 
796                         err = 0;
797                         if (fprog.filter)
798                                 err = bpf_prog_create(&active_filter, &fprog);
799                         if (!err) {
800                                 ppp_lock(ppp);
801                                 if (ppp->active_filter)
802                                         bpf_prog_destroy(ppp->active_filter);
803                                 ppp->active_filter = active_filter;
804                                 ppp_unlock(ppp);
805                         }
806                         kfree(code);
807                 }
808                 break;
809         }
810 #endif /* CONFIG_PPP_FILTER */
811 
812 #ifdef CONFIG_PPP_MULTILINK
813         case PPPIOCSMRRU:
814                 if (get_user(val, p))
815                         break;
816                 ppp_recv_lock(ppp);
817                 ppp->mrru = val;
818                 ppp_recv_unlock(ppp);
819                 err = 0;
820                 break;
821 #endif /* CONFIG_PPP_MULTILINK */
822 
823         default:
824                 err = -ENOTTY;
825         }
826         mutex_unlock(&ppp_mutex);
827         return err;
828 }
829 
830 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
831                         struct file *file, unsigned int cmd, unsigned long arg)
832 {
833         int unit, err = -EFAULT;
834         struct ppp *ppp;
835         struct channel *chan;
836         struct ppp_net *pn;
837         int __user *p = (int __user *)arg;
838 
839         mutex_lock(&ppp_mutex);
840         switch (cmd) {
841         case PPPIOCNEWUNIT:
842                 /* Create a new ppp unit */
843                 if (get_user(unit, p))
844                         break;
845                 ppp = ppp_create_interface(net, unit, file, &err);
846                 if (!ppp)
847                         break;
848                 file->private_data = &ppp->file;
849                 err = -EFAULT;
850                 if (put_user(ppp->file.index, p))
851                         break;
852                 err = 0;
853                 break;
854 
855         case PPPIOCATTACH:
856                 /* Attach to an existing ppp unit */
857                 if (get_user(unit, p))
858                         break;
859                 err = -ENXIO;
860                 pn = ppp_pernet(net);
861                 mutex_lock(&pn->all_ppp_mutex);
862                 ppp = ppp_find_unit(pn, unit);
863                 if (ppp) {
864                         atomic_inc(&ppp->file.refcnt);
865                         file->private_data = &ppp->file;
866                         err = 0;
867                 }
868                 mutex_unlock(&pn->all_ppp_mutex);
869                 break;
870 
871         case PPPIOCATTCHAN:
872                 if (get_user(unit, p))
873                         break;
874                 err = -ENXIO;
875                 pn = ppp_pernet(net);
876                 spin_lock_bh(&pn->all_channels_lock);
877                 chan = ppp_find_channel(pn, unit);
878                 if (chan) {
879                         atomic_inc(&chan->file.refcnt);
880                         file->private_data = &chan->file;
881                         err = 0;
882                 }
883                 spin_unlock_bh(&pn->all_channels_lock);
884                 break;
885 
886         default:
887                 err = -ENOTTY;
888         }
889         mutex_unlock(&ppp_mutex);
890         return err;
891 }
892 
893 static const struct file_operations ppp_device_fops = {
894         .owner          = THIS_MODULE,
895         .read           = ppp_read,
896         .write          = ppp_write,
897         .poll           = ppp_poll,
898         .unlocked_ioctl = ppp_ioctl,
899         .open           = ppp_open,
900         .release        = ppp_release,
901         .llseek         = noop_llseek,
902 };
903 
904 static __net_init int ppp_init_net(struct net *net)
905 {
906         struct ppp_net *pn = net_generic(net, ppp_net_id);
907 
908         idr_init(&pn->units_idr);
909         mutex_init(&pn->all_ppp_mutex);
910 
911         INIT_LIST_HEAD(&pn->all_channels);
912         INIT_LIST_HEAD(&pn->new_channels);
913 
914         spin_lock_init(&pn->all_channels_lock);
915 
916         return 0;
917 }
918 
919 static __net_exit void ppp_exit_net(struct net *net)
920 {
921         struct ppp_net *pn = net_generic(net, ppp_net_id);
922         struct net_device *dev;
923         struct net_device *aux;
924         struct ppp *ppp;
925         LIST_HEAD(list);
926         int id;
927 
928         rtnl_lock();
929         for_each_netdev_safe(net, dev, aux) {
930                 if (dev->netdev_ops == &ppp_netdev_ops)
931                         unregister_netdevice_queue(dev, &list);
932         }
933 
934         idr_for_each_entry(&pn->units_idr, ppp, id)
935                 /* Skip devices already unregistered by previous loop */
936                 if (!net_eq(dev_net(ppp->dev), net))
937                         unregister_netdevice_queue(ppp->dev, &list);
938 
939         unregister_netdevice_many(&list);
940         rtnl_unlock();
941 
942         idr_destroy(&pn->units_idr);
943 }
944 
945 static struct pernet_operations ppp_net_ops = {
946         .init = ppp_init_net,
947         .exit = ppp_exit_net,
948         .id   = &ppp_net_id,
949         .size = sizeof(struct ppp_net),
950 };
951 
952 #define PPP_MAJOR       108
953 
954 /* Called at boot time if ppp is compiled into the kernel,
955    or at module load time (from init_module) if compiled as a module. */
956 static int __init ppp_init(void)
957 {
958         int err;
959 
960         pr_info("PPP generic driver version " PPP_VERSION "\n");
961 
962         err = register_pernet_device(&ppp_net_ops);
963         if (err) {
964                 pr_err("failed to register PPP pernet device (%d)\n", err);
965                 goto out;
966         }
967 
968         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
969         if (err) {
970                 pr_err("failed to register PPP device (%d)\n", err);
971                 goto out_net;
972         }
973 
974         ppp_class = class_create(THIS_MODULE, "ppp");
975         if (IS_ERR(ppp_class)) {
976                 err = PTR_ERR(ppp_class);
977                 goto out_chrdev;
978         }
979 
980         /* not a big deal if we fail here :-) */
981         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
982 
983         return 0;
984 
985 out_chrdev:
986         unregister_chrdev(PPP_MAJOR, "ppp");
987 out_net:
988         unregister_pernet_device(&ppp_net_ops);
989 out:
990         return err;
991 }
992 
993 /*
994  * Network interface unit routines.
995  */
996 static netdev_tx_t
997 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
998 {
999         struct ppp *ppp = netdev_priv(dev);
1000         int npi, proto;
1001         unsigned char *pp;
1002 
1003         npi = ethertype_to_npindex(ntohs(skb->protocol));
1004         if (npi < 0)
1005                 goto outf;
1006 
1007         /* Drop, accept or reject the packet */
1008         switch (ppp->npmode[npi]) {
1009         case NPMODE_PASS:
1010                 break;
1011         case NPMODE_QUEUE:
1012                 /* it would be nice to have a way to tell the network
1013                    system to queue this one up for later. */
1014                 goto outf;
1015         case NPMODE_DROP:
1016         case NPMODE_ERROR:
1017                 goto outf;
1018         }
1019 
1020         /* Put the 2-byte PPP protocol number on the front,
1021            making sure there is room for the address and control fields. */
1022         if (skb_cow_head(skb, PPP_HDRLEN))
1023                 goto outf;
1024 
1025         pp = skb_push(skb, 2);
1026         proto = npindex_to_proto[npi];
1027         put_unaligned_be16(proto, pp);
1028 
1029         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1030         skb_queue_tail(&ppp->file.xq, skb);
1031         ppp_xmit_process(ppp);
1032         return NETDEV_TX_OK;
1033 
1034  outf:
1035         kfree_skb(skb);
1036         ++dev->stats.tx_dropped;
1037         return NETDEV_TX_OK;
1038 }
1039 
1040 static int
1041 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1042 {
1043         struct ppp *ppp = netdev_priv(dev);
1044         int err = -EFAULT;
1045         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1046         struct ppp_stats stats;
1047         struct ppp_comp_stats cstats;
1048         char *vers;
1049 
1050         switch (cmd) {
1051         case SIOCGPPPSTATS:
1052                 ppp_get_stats(ppp, &stats);
1053                 if (copy_to_user(addr, &stats, sizeof(stats)))
1054                         break;
1055                 err = 0;
1056                 break;
1057 
1058         case SIOCGPPPCSTATS:
1059                 memset(&cstats, 0, sizeof(cstats));
1060                 if (ppp->xc_state)
1061                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1062                 if (ppp->rc_state)
1063                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1064                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1065                         break;
1066                 err = 0;
1067                 break;
1068 
1069         case SIOCGPPPVER:
1070                 vers = PPP_VERSION;
1071                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1072                         break;
1073                 err = 0;
1074                 break;
1075 
1076         default:
1077                 err = -EINVAL;
1078         }
1079 
1080         return err;
1081 }
1082 
1083 static struct rtnl_link_stats64*
1084 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1085 {
1086         struct ppp *ppp = netdev_priv(dev);
1087 
1088         ppp_recv_lock(ppp);
1089         stats64->rx_packets = ppp->stats64.rx_packets;
1090         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1091         ppp_recv_unlock(ppp);
1092 
1093         ppp_xmit_lock(ppp);
1094         stats64->tx_packets = ppp->stats64.tx_packets;
1095         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1096         ppp_xmit_unlock(ppp);
1097 
1098         stats64->rx_errors        = dev->stats.rx_errors;
1099         stats64->tx_errors        = dev->stats.tx_errors;
1100         stats64->rx_dropped       = dev->stats.rx_dropped;
1101         stats64->tx_dropped       = dev->stats.tx_dropped;
1102         stats64->rx_length_errors = dev->stats.rx_length_errors;
1103 
1104         return stats64;
1105 }
1106 
1107 static struct lock_class_key ppp_tx_busylock;
1108 static int ppp_dev_init(struct net_device *dev)
1109 {
1110         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1111         return 0;
1112 }
1113 
1114 static void ppp_dev_uninit(struct net_device *dev)
1115 {
1116         struct ppp *ppp = netdev_priv(dev);
1117         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1118 
1119         ppp_lock(ppp);
1120         ppp->closing = 1;
1121         ppp_unlock(ppp);
1122 
1123         mutex_lock(&pn->all_ppp_mutex);
1124         unit_put(&pn->units_idr, ppp->file.index);
1125         mutex_unlock(&pn->all_ppp_mutex);
1126 
1127         ppp->owner = NULL;
1128 
1129         ppp->file.dead = 1;
1130         wake_up_interruptible(&ppp->file.rwait);
1131 }
1132 
1133 static const struct net_device_ops ppp_netdev_ops = {
1134         .ndo_init        = ppp_dev_init,
1135         .ndo_uninit      = ppp_dev_uninit,
1136         .ndo_start_xmit  = ppp_start_xmit,
1137         .ndo_do_ioctl    = ppp_net_ioctl,
1138         .ndo_get_stats64 = ppp_get_stats64,
1139 };
1140 
1141 static void ppp_setup(struct net_device *dev)
1142 {
1143         dev->netdev_ops = &ppp_netdev_ops;
1144         dev->hard_header_len = PPP_HDRLEN;
1145         dev->mtu = PPP_MRU;
1146         dev->addr_len = 0;
1147         dev->tx_queue_len = 3;
1148         dev->type = ARPHRD_PPP;
1149         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1150         netif_keep_dst(dev);
1151 }
1152 
1153 /*
1154  * Transmit-side routines.
1155  */
1156 
1157 /*
1158  * Called to do any work queued up on the transmit side
1159  * that can now be done.
1160  */
1161 static void
1162 ppp_xmit_process(struct ppp *ppp)
1163 {
1164         struct sk_buff *skb;
1165 
1166         ppp_xmit_lock(ppp);
1167         if (!ppp->closing) {
1168                 ppp_push(ppp);
1169                 while (!ppp->xmit_pending &&
1170                        (skb = skb_dequeue(&ppp->file.xq)))
1171                         ppp_send_frame(ppp, skb);
1172                 /* If there's no work left to do, tell the core net
1173                    code that we can accept some more. */
1174                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1175                         netif_wake_queue(ppp->dev);
1176                 else
1177                         netif_stop_queue(ppp->dev);
1178         }
1179         ppp_xmit_unlock(ppp);
1180 }
1181 
1182 static inline struct sk_buff *
1183 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1184 {
1185         struct sk_buff *new_skb;
1186         int len;
1187         int new_skb_size = ppp->dev->mtu +
1188                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1189         int compressor_skb_size = ppp->dev->mtu +
1190                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1191         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1192         if (!new_skb) {
1193                 if (net_ratelimit())
1194                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1195                 return NULL;
1196         }
1197         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1198                 skb_reserve(new_skb,
1199                             ppp->dev->hard_header_len - PPP_HDRLEN);
1200 
1201         /* compressor still expects A/C bytes in hdr */
1202         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1203                                    new_skb->data, skb->len + 2,
1204                                    compressor_skb_size);
1205         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1206                 consume_skb(skb);
1207                 skb = new_skb;
1208                 skb_put(skb, len);
1209                 skb_pull(skb, 2);       /* pull off A/C bytes */
1210         } else if (len == 0) {
1211                 /* didn't compress, or CCP not up yet */
1212                 consume_skb(new_skb);
1213                 new_skb = skb;
1214         } else {
1215                 /*
1216                  * (len < 0)
1217                  * MPPE requires that we do not send unencrypted
1218                  * frames.  The compressor will return -1 if we
1219                  * should drop the frame.  We cannot simply test
1220                  * the compress_proto because MPPE and MPPC share
1221                  * the same number.
1222                  */
1223                 if (net_ratelimit())
1224                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1225                 kfree_skb(skb);
1226                 consume_skb(new_skb);
1227                 new_skb = NULL;
1228         }
1229         return new_skb;
1230 }
1231 
1232 /*
1233  * Compress and send a frame.
1234  * The caller should have locked the xmit path,
1235  * and xmit_pending should be 0.
1236  */
1237 static void
1238 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1239 {
1240         int proto = PPP_PROTO(skb);
1241         struct sk_buff *new_skb;
1242         int len;
1243         unsigned char *cp;
1244 
1245         if (proto < 0x8000) {
1246 #ifdef CONFIG_PPP_FILTER
1247                 /* check if we should pass this packet */
1248                 /* the filter instructions are constructed assuming
1249                    a four-byte PPP header on each packet */
1250                 *skb_push(skb, 2) = 1;
1251                 if (ppp->pass_filter &&
1252                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1253                         if (ppp->debug & 1)
1254                                 netdev_printk(KERN_DEBUG, ppp->dev,
1255                                               "PPP: outbound frame "
1256                                               "not passed\n");
1257                         kfree_skb(skb);
1258                         return;
1259                 }
1260                 /* if this packet passes the active filter, record the time */
1261                 if (!(ppp->active_filter &&
1262                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1263                         ppp->last_xmit = jiffies;
1264                 skb_pull(skb, 2);
1265 #else
1266                 /* for data packets, record the time */
1267                 ppp->last_xmit = jiffies;
1268 #endif /* CONFIG_PPP_FILTER */
1269         }
1270 
1271         ++ppp->stats64.tx_packets;
1272         ppp->stats64.tx_bytes += skb->len - 2;
1273 
1274         switch (proto) {
1275         case PPP_IP:
1276                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1277                         break;
1278                 /* try to do VJ TCP header compression */
1279                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1280                                     GFP_ATOMIC);
1281                 if (!new_skb) {
1282                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1283                         goto drop;
1284                 }
1285                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1286                 cp = skb->data + 2;
1287                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1288                                     new_skb->data + 2, &cp,
1289                                     !(ppp->flags & SC_NO_TCP_CCID));
1290                 if (cp == skb->data + 2) {
1291                         /* didn't compress */
1292                         consume_skb(new_skb);
1293                 } else {
1294                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1295                                 proto = PPP_VJC_COMP;
1296                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1297                         } else {
1298                                 proto = PPP_VJC_UNCOMP;
1299                                 cp[0] = skb->data[2];
1300                         }
1301                         consume_skb(skb);
1302                         skb = new_skb;
1303                         cp = skb_put(skb, len + 2);
1304                         cp[0] = 0;
1305                         cp[1] = proto;
1306                 }
1307                 break;
1308 
1309         case PPP_CCP:
1310                 /* peek at outbound CCP frames */
1311                 ppp_ccp_peek(ppp, skb, 0);
1312                 break;
1313         }
1314 
1315         /* try to do packet compression */
1316         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1317             proto != PPP_LCP && proto != PPP_CCP) {
1318                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1319                         if (net_ratelimit())
1320                                 netdev_err(ppp->dev,
1321                                            "ppp: compression required but "
1322                                            "down - pkt dropped.\n");
1323                         goto drop;
1324                 }
1325                 skb = pad_compress_skb(ppp, skb);
1326                 if (!skb)
1327                         goto drop;
1328         }
1329 
1330         /*
1331          * If we are waiting for traffic (demand dialling),
1332          * queue it up for pppd to receive.
1333          */
1334         if (ppp->flags & SC_LOOP_TRAFFIC) {
1335                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1336                         goto drop;
1337                 skb_queue_tail(&ppp->file.rq, skb);
1338                 wake_up_interruptible(&ppp->file.rwait);
1339                 return;
1340         }
1341 
1342         ppp->xmit_pending = skb;
1343         ppp_push(ppp);
1344         return;
1345 
1346  drop:
1347         kfree_skb(skb);
1348         ++ppp->dev->stats.tx_errors;
1349 }
1350 
1351 /*
1352  * Try to send the frame in xmit_pending.
1353  * The caller should have the xmit path locked.
1354  */
1355 static void
1356 ppp_push(struct ppp *ppp)
1357 {
1358         struct list_head *list;
1359         struct channel *pch;
1360         struct sk_buff *skb = ppp->xmit_pending;
1361 
1362         if (!skb)
1363                 return;
1364 
1365         list = &ppp->channels;
1366         if (list_empty(list)) {
1367                 /* nowhere to send the packet, just drop it */
1368                 ppp->xmit_pending = NULL;
1369                 kfree_skb(skb);
1370                 return;
1371         }
1372 
1373         if ((ppp->flags & SC_MULTILINK) == 0) {
1374                 /* not doing multilink: send it down the first channel */
1375                 list = list->next;
1376                 pch = list_entry(list, struct channel, clist);
1377 
1378                 spin_lock_bh(&pch->downl);
1379                 if (pch->chan) {
1380                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1381                                 ppp->xmit_pending = NULL;
1382                 } else {
1383                         /* channel got unregistered */
1384                         kfree_skb(skb);
1385                         ppp->xmit_pending = NULL;
1386                 }
1387                 spin_unlock_bh(&pch->downl);
1388                 return;
1389         }
1390 
1391 #ifdef CONFIG_PPP_MULTILINK
1392         /* Multilink: fragment the packet over as many links
1393            as can take the packet at the moment. */
1394         if (!ppp_mp_explode(ppp, skb))
1395                 return;
1396 #endif /* CONFIG_PPP_MULTILINK */
1397 
1398         ppp->xmit_pending = NULL;
1399         kfree_skb(skb);
1400 }
1401 
1402 #ifdef CONFIG_PPP_MULTILINK
1403 static bool mp_protocol_compress __read_mostly = true;
1404 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1405 MODULE_PARM_DESC(mp_protocol_compress,
1406                  "compress protocol id in multilink fragments");
1407 
1408 /*
1409  * Divide a packet to be transmitted into fragments and
1410  * send them out the individual links.
1411  */
1412 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1413 {
1414         int len, totlen;
1415         int i, bits, hdrlen, mtu;
1416         int flen;
1417         int navail, nfree, nzero;
1418         int nbigger;
1419         int totspeed;
1420         int totfree;
1421         unsigned char *p, *q;
1422         struct list_head *list;
1423         struct channel *pch;
1424         struct sk_buff *frag;
1425         struct ppp_channel *chan;
1426 
1427         totspeed = 0; /*total bitrate of the bundle*/
1428         nfree = 0; /* # channels which have no packet already queued */
1429         navail = 0; /* total # of usable channels (not deregistered) */
1430         nzero = 0; /* number of channels with zero speed associated*/
1431         totfree = 0; /*total # of channels available and
1432                                   *having no queued packets before
1433                                   *starting the fragmentation*/
1434 
1435         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1436         i = 0;
1437         list_for_each_entry(pch, &ppp->channels, clist) {
1438                 if (pch->chan) {
1439                         pch->avail = 1;
1440                         navail++;
1441                         pch->speed = pch->chan->speed;
1442                 } else {
1443                         pch->avail = 0;
1444                 }
1445                 if (pch->avail) {
1446                         if (skb_queue_empty(&pch->file.xq) ||
1447                                 !pch->had_frag) {
1448                                         if (pch->speed == 0)
1449                                                 nzero++;
1450                                         else
1451                                                 totspeed += pch->speed;
1452 
1453                                         pch->avail = 2;
1454                                         ++nfree;
1455                                         ++totfree;
1456                                 }
1457                         if (!pch->had_frag && i < ppp->nxchan)
1458                                 ppp->nxchan = i;
1459                 }
1460                 ++i;
1461         }
1462         /*
1463          * Don't start sending this packet unless at least half of
1464          * the channels are free.  This gives much better TCP
1465          * performance if we have a lot of channels.
1466          */
1467         if (nfree == 0 || nfree < navail / 2)
1468                 return 0; /* can't take now, leave it in xmit_pending */
1469 
1470         /* Do protocol field compression */
1471         p = skb->data;
1472         len = skb->len;
1473         if (*p == 0 && mp_protocol_compress) {
1474                 ++p;
1475                 --len;
1476         }
1477 
1478         totlen = len;
1479         nbigger = len % nfree;
1480 
1481         /* skip to the channel after the one we last used
1482            and start at that one */
1483         list = &ppp->channels;
1484         for (i = 0; i < ppp->nxchan; ++i) {
1485                 list = list->next;
1486                 if (list == &ppp->channels) {
1487                         i = 0;
1488                         break;
1489                 }
1490         }
1491 
1492         /* create a fragment for each channel */
1493         bits = B;
1494         while (len > 0) {
1495                 list = list->next;
1496                 if (list == &ppp->channels) {
1497                         i = 0;
1498                         continue;
1499                 }
1500                 pch = list_entry(list, struct channel, clist);
1501                 ++i;
1502                 if (!pch->avail)
1503                         continue;
1504 
1505                 /*
1506                  * Skip this channel if it has a fragment pending already and
1507                  * we haven't given a fragment to all of the free channels.
1508                  */
1509                 if (pch->avail == 1) {
1510                         if (nfree > 0)
1511                                 continue;
1512                 } else {
1513                         pch->avail = 1;
1514                 }
1515 
1516                 /* check the channel's mtu and whether it is still attached. */
1517                 spin_lock_bh(&pch->downl);
1518                 if (pch->chan == NULL) {
1519                         /* can't use this channel, it's being deregistered */
1520                         if (pch->speed == 0)
1521                                 nzero--;
1522                         else
1523                                 totspeed -= pch->speed;
1524 
1525                         spin_unlock_bh(&pch->downl);
1526                         pch->avail = 0;
1527                         totlen = len;
1528                         totfree--;
1529                         nfree--;
1530                         if (--navail == 0)
1531                                 break;
1532                         continue;
1533                 }
1534 
1535                 /*
1536                 *if the channel speed is not set divide
1537                 *the packet evenly among the free channels;
1538                 *otherwise divide it according to the speed
1539                 *of the channel we are going to transmit on
1540                 */
1541                 flen = len;
1542                 if (nfree > 0) {
1543                         if (pch->speed == 0) {
1544                                 flen = len/nfree;
1545                                 if (nbigger > 0) {
1546                                         flen++;
1547                                         nbigger--;
1548                                 }
1549                         } else {
1550                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1551                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1552                                 if (nbigger > 0) {
1553                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1554                                         nbigger -= ((totfree - nzero)*pch->speed)/
1555                                                         totspeed;
1556                                 }
1557                         }
1558                         nfree--;
1559                 }
1560 
1561                 /*
1562                  *check if we are on the last channel or
1563                  *we exceded the length of the data to
1564                  *fragment
1565                  */
1566                 if ((nfree <= 0) || (flen > len))
1567                         flen = len;
1568                 /*
1569                  *it is not worth to tx on slow channels:
1570                  *in that case from the resulting flen according to the
1571                  *above formula will be equal or less than zero.
1572                  *Skip the channel in this case
1573                  */
1574                 if (flen <= 0) {
1575                         pch->avail = 2;
1576                         spin_unlock_bh(&pch->downl);
1577                         continue;
1578                 }
1579 
1580                 /*
1581                  * hdrlen includes the 2-byte PPP protocol field, but the
1582                  * MTU counts only the payload excluding the protocol field.
1583                  * (RFC1661 Section 2)
1584                  */
1585                 mtu = pch->chan->mtu - (hdrlen - 2);
1586                 if (mtu < 4)
1587                         mtu = 4;
1588                 if (flen > mtu)
1589                         flen = mtu;
1590                 if (flen == len)
1591                         bits |= E;
1592                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1593                 if (!frag)
1594                         goto noskb;
1595                 q = skb_put(frag, flen + hdrlen);
1596 
1597                 /* make the MP header */
1598                 put_unaligned_be16(PPP_MP, q);
1599                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1600                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1601                         q[3] = ppp->nxseq;
1602                 } else {
1603                         q[2] = bits;
1604                         q[3] = ppp->nxseq >> 16;
1605                         q[4] = ppp->nxseq >> 8;
1606                         q[5] = ppp->nxseq;
1607                 }
1608 
1609                 memcpy(q + hdrlen, p, flen);
1610 
1611                 /* try to send it down the channel */
1612                 chan = pch->chan;
1613                 if (!skb_queue_empty(&pch->file.xq) ||
1614                         !chan->ops->start_xmit(chan, frag))
1615                         skb_queue_tail(&pch->file.xq, frag);
1616                 pch->had_frag = 1;
1617                 p += flen;
1618                 len -= flen;
1619                 ++ppp->nxseq;
1620                 bits = 0;
1621                 spin_unlock_bh(&pch->downl);
1622         }
1623         ppp->nxchan = i;
1624 
1625         return 1;
1626 
1627  noskb:
1628         spin_unlock_bh(&pch->downl);
1629         if (ppp->debug & 1)
1630                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1631         ++ppp->dev->stats.tx_errors;
1632         ++ppp->nxseq;
1633         return 1;       /* abandon the frame */
1634 }
1635 #endif /* CONFIG_PPP_MULTILINK */
1636 
1637 /*
1638  * Try to send data out on a channel.
1639  */
1640 static void
1641 ppp_channel_push(struct channel *pch)
1642 {
1643         struct sk_buff *skb;
1644         struct ppp *ppp;
1645 
1646         spin_lock_bh(&pch->downl);
1647         if (pch->chan) {
1648                 while (!skb_queue_empty(&pch->file.xq)) {
1649                         skb = skb_dequeue(&pch->file.xq);
1650                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1651                                 /* put the packet back and try again later */
1652                                 skb_queue_head(&pch->file.xq, skb);
1653                                 break;
1654                         }
1655                 }
1656         } else {
1657                 /* channel got deregistered */
1658                 skb_queue_purge(&pch->file.xq);
1659         }
1660         spin_unlock_bh(&pch->downl);
1661         /* see if there is anything from the attached unit to be sent */
1662         if (skb_queue_empty(&pch->file.xq)) {
1663                 read_lock_bh(&pch->upl);
1664                 ppp = pch->ppp;
1665                 if (ppp)
1666                         ppp_xmit_process(ppp);
1667                 read_unlock_bh(&pch->upl);
1668         }
1669 }
1670 
1671 /*
1672  * Receive-side routines.
1673  */
1674 
1675 struct ppp_mp_skb_parm {
1676         u32             sequence;
1677         u8              BEbits;
1678 };
1679 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1680 
1681 static inline void
1682 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1683 {
1684         ppp_recv_lock(ppp);
1685         if (!ppp->closing)
1686                 ppp_receive_frame(ppp, skb, pch);
1687         else
1688                 kfree_skb(skb);
1689         ppp_recv_unlock(ppp);
1690 }
1691 
1692 void
1693 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1694 {
1695         struct channel *pch = chan->ppp;
1696         int proto;
1697 
1698         if (!pch) {
1699                 kfree_skb(skb);
1700                 return;
1701         }
1702 
1703         read_lock_bh(&pch->upl);
1704         if (!pskb_may_pull(skb, 2)) {
1705                 kfree_skb(skb);
1706                 if (pch->ppp) {
1707                         ++pch->ppp->dev->stats.rx_length_errors;
1708                         ppp_receive_error(pch->ppp);
1709                 }
1710                 goto done;
1711         }
1712 
1713         proto = PPP_PROTO(skb);
1714         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1715                 /* put it on the channel queue */
1716                 skb_queue_tail(&pch->file.rq, skb);
1717                 /* drop old frames if queue too long */
1718                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1719                        (skb = skb_dequeue(&pch->file.rq)))
1720                         kfree_skb(skb);
1721                 wake_up_interruptible(&pch->file.rwait);
1722         } else {
1723                 ppp_do_recv(pch->ppp, skb, pch);
1724         }
1725 
1726 done:
1727         read_unlock_bh(&pch->upl);
1728 }
1729 
1730 /* Put a 0-length skb in the receive queue as an error indication */
1731 void
1732 ppp_input_error(struct ppp_channel *chan, int code)
1733 {
1734         struct channel *pch = chan->ppp;
1735         struct sk_buff *skb;
1736 
1737         if (!pch)
1738                 return;
1739 
1740         read_lock_bh(&pch->upl);
1741         if (pch->ppp) {
1742                 skb = alloc_skb(0, GFP_ATOMIC);
1743                 if (skb) {
1744                         skb->len = 0;           /* probably unnecessary */
1745                         skb->cb[0] = code;
1746                         ppp_do_recv(pch->ppp, skb, pch);
1747                 }
1748         }
1749         read_unlock_bh(&pch->upl);
1750 }
1751 
1752 /*
1753  * We come in here to process a received frame.
1754  * The receive side of the ppp unit is locked.
1755  */
1756 static void
1757 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1758 {
1759         /* note: a 0-length skb is used as an error indication */
1760         if (skb->len > 0) {
1761                 skb_checksum_complete_unset(skb);
1762 #ifdef CONFIG_PPP_MULTILINK
1763                 /* XXX do channel-level decompression here */
1764                 if (PPP_PROTO(skb) == PPP_MP)
1765                         ppp_receive_mp_frame(ppp, skb, pch);
1766                 else
1767 #endif /* CONFIG_PPP_MULTILINK */
1768                         ppp_receive_nonmp_frame(ppp, skb);
1769         } else {
1770                 kfree_skb(skb);
1771                 ppp_receive_error(ppp);
1772         }
1773 }
1774 
1775 static void
1776 ppp_receive_error(struct ppp *ppp)
1777 {
1778         ++ppp->dev->stats.rx_errors;
1779         if (ppp->vj)
1780                 slhc_toss(ppp->vj);
1781 }
1782 
1783 static void
1784 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1785 {
1786         struct sk_buff *ns;
1787         int proto, len, npi;
1788 
1789         /*
1790          * Decompress the frame, if compressed.
1791          * Note that some decompressors need to see uncompressed frames
1792          * that come in as well as compressed frames.
1793          */
1794         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1795             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1796                 skb = ppp_decompress_frame(ppp, skb);
1797 
1798         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1799                 goto err;
1800 
1801         proto = PPP_PROTO(skb);
1802         switch (proto) {
1803         case PPP_VJC_COMP:
1804                 /* decompress VJ compressed packets */
1805                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1806                         goto err;
1807 
1808                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1809                         /* copy to a new sk_buff with more tailroom */
1810                         ns = dev_alloc_skb(skb->len + 128);
1811                         if (!ns) {
1812                                 netdev_err(ppp->dev, "PPP: no memory "
1813                                            "(VJ decomp)\n");
1814                                 goto err;
1815                         }
1816                         skb_reserve(ns, 2);
1817                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1818                         consume_skb(skb);
1819                         skb = ns;
1820                 }
1821                 else
1822                         skb->ip_summed = CHECKSUM_NONE;
1823 
1824                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1825                 if (len <= 0) {
1826                         netdev_printk(KERN_DEBUG, ppp->dev,
1827                                       "PPP: VJ decompression error\n");
1828                         goto err;
1829                 }
1830                 len += 2;
1831                 if (len > skb->len)
1832                         skb_put(skb, len - skb->len);
1833                 else if (len < skb->len)
1834                         skb_trim(skb, len);
1835                 proto = PPP_IP;
1836                 break;
1837 
1838         case PPP_VJC_UNCOMP:
1839                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1840                         goto err;
1841 
1842                 /* Until we fix the decompressor need to make sure
1843                  * data portion is linear.
1844                  */
1845                 if (!pskb_may_pull(skb, skb->len))
1846                         goto err;
1847 
1848                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1849                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1850                         goto err;
1851                 }
1852                 proto = PPP_IP;
1853                 break;
1854 
1855         case PPP_CCP:
1856                 ppp_ccp_peek(ppp, skb, 1);
1857                 break;
1858         }
1859 
1860         ++ppp->stats64.rx_packets;
1861         ppp->stats64.rx_bytes += skb->len - 2;
1862 
1863         npi = proto_to_npindex(proto);
1864         if (npi < 0) {
1865                 /* control or unknown frame - pass it to pppd */
1866                 skb_queue_tail(&ppp->file.rq, skb);
1867                 /* limit queue length by dropping old frames */
1868                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1869                        (skb = skb_dequeue(&ppp->file.rq)))
1870                         kfree_skb(skb);
1871                 /* wake up any process polling or blocking on read */
1872                 wake_up_interruptible(&ppp->file.rwait);
1873 
1874         } else {
1875                 /* network protocol frame - give it to the kernel */
1876 
1877 #ifdef CONFIG_PPP_FILTER
1878                 /* check if the packet passes the pass and active filters */
1879                 /* the filter instructions are constructed assuming
1880                    a four-byte PPP header on each packet */
1881                 if (ppp->pass_filter || ppp->active_filter) {
1882                         if (skb_unclone(skb, GFP_ATOMIC))
1883                                 goto err;
1884 
1885                         *skb_push(skb, 2) = 0;
1886                         if (ppp->pass_filter &&
1887                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1888                                 if (ppp->debug & 1)
1889                                         netdev_printk(KERN_DEBUG, ppp->dev,
1890                                                       "PPP: inbound frame "
1891                                                       "not passed\n");
1892                                 kfree_skb(skb);
1893                                 return;
1894                         }
1895                         if (!(ppp->active_filter &&
1896                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1897                                 ppp->last_recv = jiffies;
1898                         __skb_pull(skb, 2);
1899                 } else
1900 #endif /* CONFIG_PPP_FILTER */
1901                         ppp->last_recv = jiffies;
1902 
1903                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1904                     ppp->npmode[npi] != NPMODE_PASS) {
1905                         kfree_skb(skb);
1906                 } else {
1907                         /* chop off protocol */
1908                         skb_pull_rcsum(skb, 2);
1909                         skb->dev = ppp->dev;
1910                         skb->protocol = htons(npindex_to_ethertype[npi]);
1911                         skb_reset_mac_header(skb);
1912                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1913                                                       dev_net(ppp->dev)));
1914                         netif_rx(skb);
1915                 }
1916         }
1917         return;
1918 
1919  err:
1920         kfree_skb(skb);
1921         ppp_receive_error(ppp);
1922 }
1923 
1924 static struct sk_buff *
1925 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1926 {
1927         int proto = PPP_PROTO(skb);
1928         struct sk_buff *ns;
1929         int len;
1930 
1931         /* Until we fix all the decompressor's need to make sure
1932          * data portion is linear.
1933          */
1934         if (!pskb_may_pull(skb, skb->len))
1935                 goto err;
1936 
1937         if (proto == PPP_COMP) {
1938                 int obuff_size;
1939 
1940                 switch(ppp->rcomp->compress_proto) {
1941                 case CI_MPPE:
1942                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1943                         break;
1944                 default:
1945                         obuff_size = ppp->mru + PPP_HDRLEN;
1946                         break;
1947                 }
1948 
1949                 ns = dev_alloc_skb(obuff_size);
1950                 if (!ns) {
1951                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1952                                    "no memory\n");
1953                         goto err;
1954                 }
1955                 /* the decompressor still expects the A/C bytes in the hdr */
1956                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1957                                 skb->len + 2, ns->data, obuff_size);
1958                 if (len < 0) {
1959                         /* Pass the compressed frame to pppd as an
1960                            error indication. */
1961                         if (len == DECOMP_FATALERROR)
1962                                 ppp->rstate |= SC_DC_FERROR;
1963                         kfree_skb(ns);
1964                         goto err;
1965                 }
1966 
1967                 consume_skb(skb);
1968                 skb = ns;
1969                 skb_put(skb, len);
1970                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1971 
1972         } else {
1973                 /* Uncompressed frame - pass to decompressor so it
1974                    can update its dictionary if necessary. */
1975                 if (ppp->rcomp->incomp)
1976                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1977                                            skb->len + 2);
1978         }
1979 
1980         return skb;
1981 
1982  err:
1983         ppp->rstate |= SC_DC_ERROR;
1984         ppp_receive_error(ppp);
1985         return skb;
1986 }
1987 
1988 #ifdef CONFIG_PPP_MULTILINK
1989 /*
1990  * Receive a multilink frame.
1991  * We put it on the reconstruction queue and then pull off
1992  * as many completed frames as we can.
1993  */
1994 static void
1995 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1996 {
1997         u32 mask, seq;
1998         struct channel *ch;
1999         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2000 
2001         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2002                 goto err;               /* no good, throw it away */
2003 
2004         /* Decode sequence number and begin/end bits */
2005         if (ppp->flags & SC_MP_SHORTSEQ) {
2006                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2007                 mask = 0xfff;
2008         } else {
2009                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2010                 mask = 0xffffff;
2011         }
2012         PPP_MP_CB(skb)->BEbits = skb->data[2];
2013         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2014 
2015         /*
2016          * Do protocol ID decompression on the first fragment of each packet.
2017          */
2018         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2019                 *skb_push(skb, 1) = 0;
2020 
2021         /*
2022          * Expand sequence number to 32 bits, making it as close
2023          * as possible to ppp->minseq.
2024          */
2025         seq |= ppp->minseq & ~mask;
2026         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2027                 seq += mask + 1;
2028         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2029                 seq -= mask + 1;        /* should never happen */
2030         PPP_MP_CB(skb)->sequence = seq;
2031         pch->lastseq = seq;
2032 
2033         /*
2034          * If this packet comes before the next one we were expecting,
2035          * drop it.
2036          */
2037         if (seq_before(seq, ppp->nextseq)) {
2038                 kfree_skb(skb);
2039                 ++ppp->dev->stats.rx_dropped;
2040                 ppp_receive_error(ppp);
2041                 return;
2042         }
2043 
2044         /*
2045          * Reevaluate minseq, the minimum over all channels of the
2046          * last sequence number received on each channel.  Because of
2047          * the increasing sequence number rule, we know that any fragment
2048          * before `minseq' which hasn't arrived is never going to arrive.
2049          * The list of channels can't change because we have the receive
2050          * side of the ppp unit locked.
2051          */
2052         list_for_each_entry(ch, &ppp->channels, clist) {
2053                 if (seq_before(ch->lastseq, seq))
2054                         seq = ch->lastseq;
2055         }
2056         if (seq_before(ppp->minseq, seq))
2057                 ppp->minseq = seq;
2058 
2059         /* Put the fragment on the reconstruction queue */
2060         ppp_mp_insert(ppp, skb);
2061 
2062         /* If the queue is getting long, don't wait any longer for packets
2063            before the start of the queue. */
2064         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2065                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2066                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2067                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2068         }
2069 
2070         /* Pull completed packets off the queue and receive them. */
2071         while ((skb = ppp_mp_reconstruct(ppp))) {
2072                 if (pskb_may_pull(skb, 2))
2073                         ppp_receive_nonmp_frame(ppp, skb);
2074                 else {
2075                         ++ppp->dev->stats.rx_length_errors;
2076                         kfree_skb(skb);
2077                         ppp_receive_error(ppp);
2078                 }
2079         }
2080 
2081         return;
2082 
2083  err:
2084         kfree_skb(skb);
2085         ppp_receive_error(ppp);
2086 }
2087 
2088 /*
2089  * Insert a fragment on the MP reconstruction queue.
2090  * The queue is ordered by increasing sequence number.
2091  */
2092 static void
2093 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2094 {
2095         struct sk_buff *p;
2096         struct sk_buff_head *list = &ppp->mrq;
2097         u32 seq = PPP_MP_CB(skb)->sequence;
2098 
2099         /* N.B. we don't need to lock the list lock because we have the
2100            ppp unit receive-side lock. */
2101         skb_queue_walk(list, p) {
2102                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2103                         break;
2104         }
2105         __skb_queue_before(list, p, skb);
2106 }
2107 
2108 /*
2109  * Reconstruct a packet from the MP fragment queue.
2110  * We go through increasing sequence numbers until we find a
2111  * complete packet, or we get to the sequence number for a fragment
2112  * which hasn't arrived but might still do so.
2113  */
2114 static struct sk_buff *
2115 ppp_mp_reconstruct(struct ppp *ppp)
2116 {
2117         u32 seq = ppp->nextseq;
2118         u32 minseq = ppp->minseq;
2119         struct sk_buff_head *list = &ppp->mrq;
2120         struct sk_buff *p, *tmp;
2121         struct sk_buff *head, *tail;
2122         struct sk_buff *skb = NULL;
2123         int lost = 0, len = 0;
2124 
2125         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2126                 return NULL;
2127         head = list->next;
2128         tail = NULL;
2129         skb_queue_walk_safe(list, p, tmp) {
2130         again:
2131                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2132                         /* this can't happen, anyway ignore the skb */
2133                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2134                                    "seq %u < %u\n",
2135                                    PPP_MP_CB(p)->sequence, seq);
2136                         __skb_unlink(p, list);
2137                         kfree_skb(p);
2138                         continue;
2139                 }
2140                 if (PPP_MP_CB(p)->sequence != seq) {
2141                         u32 oldseq;
2142                         /* Fragment `seq' is missing.  If it is after
2143                            minseq, it might arrive later, so stop here. */
2144                         if (seq_after(seq, minseq))
2145                                 break;
2146                         /* Fragment `seq' is lost, keep going. */
2147                         lost = 1;
2148                         oldseq = seq;
2149                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2150                                 minseq + 1: PPP_MP_CB(p)->sequence;
2151 
2152                         if (ppp->debug & 1)
2153                                 netdev_printk(KERN_DEBUG, ppp->dev,
2154                                               "lost frag %u..%u\n",
2155                                               oldseq, seq-1);
2156 
2157                         goto again;
2158                 }
2159 
2160                 /*
2161                  * At this point we know that all the fragments from
2162                  * ppp->nextseq to seq are either present or lost.
2163                  * Also, there are no complete packets in the queue
2164                  * that have no missing fragments and end before this
2165                  * fragment.
2166                  */
2167 
2168                 /* B bit set indicates this fragment starts a packet */
2169                 if (PPP_MP_CB(p)->BEbits & B) {
2170                         head = p;
2171                         lost = 0;
2172                         len = 0;
2173                 }
2174 
2175                 len += p->len;
2176 
2177                 /* Got a complete packet yet? */
2178                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2179                     (PPP_MP_CB(head)->BEbits & B)) {
2180                         if (len > ppp->mrru + 2) {
2181                                 ++ppp->dev->stats.rx_length_errors;
2182                                 netdev_printk(KERN_DEBUG, ppp->dev,
2183                                               "PPP: reconstructed packet"
2184                                               " is too long (%d)\n", len);
2185                         } else {
2186                                 tail = p;
2187                                 break;
2188                         }
2189                         ppp->nextseq = seq + 1;
2190                 }
2191 
2192                 /*
2193                  * If this is the ending fragment of a packet,
2194                  * and we haven't found a complete valid packet yet,
2195                  * we can discard up to and including this fragment.
2196                  */
2197                 if (PPP_MP_CB(p)->BEbits & E) {
2198                         struct sk_buff *tmp2;
2199 
2200                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2201                                 if (ppp->debug & 1)
2202                                         netdev_printk(KERN_DEBUG, ppp->dev,
2203                                                       "discarding frag %u\n",
2204                                                       PPP_MP_CB(p)->sequence);
2205                                 __skb_unlink(p, list);
2206                                 kfree_skb(p);
2207                         }
2208                         head = skb_peek(list);
2209                         if (!head)
2210                                 break;
2211                 }
2212                 ++seq;
2213         }
2214 
2215         /* If we have a complete packet, copy it all into one skb. */
2216         if (tail != NULL) {
2217                 /* If we have discarded any fragments,
2218                    signal a receive error. */
2219                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2220                         skb_queue_walk_safe(list, p, tmp) {
2221                                 if (p == head)
2222                                         break;
2223                                 if (ppp->debug & 1)
2224                                         netdev_printk(KERN_DEBUG, ppp->dev,
2225                                                       "discarding frag %u\n",
2226                                                       PPP_MP_CB(p)->sequence);
2227                                 __skb_unlink(p, list);
2228                                 kfree_skb(p);
2229                         }
2230 
2231                         if (ppp->debug & 1)
2232                                 netdev_printk(KERN_DEBUG, ppp->dev,
2233                                               "  missed pkts %u..%u\n",
2234                                               ppp->nextseq,
2235                                               PPP_MP_CB(head)->sequence-1);
2236                         ++ppp->dev->stats.rx_dropped;
2237                         ppp_receive_error(ppp);
2238                 }
2239 
2240                 skb = head;
2241                 if (head != tail) {
2242                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2243                         p = skb_queue_next(list, head);
2244                         __skb_unlink(skb, list);
2245                         skb_queue_walk_from_safe(list, p, tmp) {
2246                                 __skb_unlink(p, list);
2247                                 *fragpp = p;
2248                                 p->next = NULL;
2249                                 fragpp = &p->next;
2250 
2251                                 skb->len += p->len;
2252                                 skb->data_len += p->len;
2253                                 skb->truesize += p->truesize;
2254 
2255                                 if (p == tail)
2256                                         break;
2257                         }
2258                 } else {
2259                         __skb_unlink(skb, list);
2260                 }
2261 
2262                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2263         }
2264 
2265         return skb;
2266 }
2267 #endif /* CONFIG_PPP_MULTILINK */
2268 
2269 /*
2270  * Channel interface.
2271  */
2272 
2273 /* Create a new, unattached ppp channel. */
2274 int ppp_register_channel(struct ppp_channel *chan)
2275 {
2276         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2277 }
2278 
2279 /* Create a new, unattached ppp channel for specified net. */
2280 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2281 {
2282         struct channel *pch;
2283         struct ppp_net *pn;
2284 
2285         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2286         if (!pch)
2287                 return -ENOMEM;
2288 
2289         pn = ppp_pernet(net);
2290 
2291         pch->ppp = NULL;
2292         pch->chan = chan;
2293         pch->chan_net = net;
2294         chan->ppp = pch;
2295         init_ppp_file(&pch->file, CHANNEL);
2296         pch->file.hdrlen = chan->hdrlen;
2297 #ifdef CONFIG_PPP_MULTILINK
2298         pch->lastseq = -1;
2299 #endif /* CONFIG_PPP_MULTILINK */
2300         init_rwsem(&pch->chan_sem);
2301         spin_lock_init(&pch->downl);
2302         rwlock_init(&pch->upl);
2303 
2304         spin_lock_bh(&pn->all_channels_lock);
2305         pch->file.index = ++pn->last_channel_index;
2306         list_add(&pch->list, &pn->new_channels);
2307         atomic_inc(&channel_count);
2308         spin_unlock_bh(&pn->all_channels_lock);
2309 
2310         return 0;
2311 }
2312 
2313 /*
2314  * Return the index of a channel.
2315  */
2316 int ppp_channel_index(struct ppp_channel *chan)
2317 {
2318         struct channel *pch = chan->ppp;
2319 
2320         if (pch)
2321                 return pch->file.index;
2322         return -1;
2323 }
2324 
2325 /*
2326  * Return the PPP unit number to which a channel is connected.
2327  */
2328 int ppp_unit_number(struct ppp_channel *chan)
2329 {
2330         struct channel *pch = chan->ppp;
2331         int unit = -1;
2332 
2333         if (pch) {
2334                 read_lock_bh(&pch->upl);
2335                 if (pch->ppp)
2336                         unit = pch->ppp->file.index;
2337                 read_unlock_bh(&pch->upl);
2338         }
2339         return unit;
2340 }
2341 
2342 /*
2343  * Return the PPP device interface name of a channel.
2344  */
2345 char *ppp_dev_name(struct ppp_channel *chan)
2346 {
2347         struct channel *pch = chan->ppp;
2348         char *name = NULL;
2349 
2350         if (pch) {
2351                 read_lock_bh(&pch->upl);
2352                 if (pch->ppp && pch->ppp->dev)
2353                         name = pch->ppp->dev->name;
2354                 read_unlock_bh(&pch->upl);
2355         }
2356         return name;
2357 }
2358 
2359 
2360 /*
2361  * Disconnect a channel from the generic layer.
2362  * This must be called in process context.
2363  */
2364 void
2365 ppp_unregister_channel(struct ppp_channel *chan)
2366 {
2367         struct channel *pch = chan->ppp;
2368         struct ppp_net *pn;
2369 
2370         if (!pch)
2371                 return;         /* should never happen */
2372 
2373         chan->ppp = NULL;
2374 
2375         /*
2376          * This ensures that we have returned from any calls into the
2377          * the channel's start_xmit or ioctl routine before we proceed.
2378          */
2379         down_write(&pch->chan_sem);
2380         spin_lock_bh(&pch->downl);
2381         pch->chan = NULL;
2382         spin_unlock_bh(&pch->downl);
2383         up_write(&pch->chan_sem);
2384         ppp_disconnect_channel(pch);
2385 
2386         pn = ppp_pernet(pch->chan_net);
2387         spin_lock_bh(&pn->all_channels_lock);
2388         list_del(&pch->list);
2389         spin_unlock_bh(&pn->all_channels_lock);
2390 
2391         pch->file.dead = 1;
2392         wake_up_interruptible(&pch->file.rwait);
2393         if (atomic_dec_and_test(&pch->file.refcnt))
2394                 ppp_destroy_channel(pch);
2395 }
2396 
2397 /*
2398  * Callback from a channel when it can accept more to transmit.
2399  * This should be called at BH/softirq level, not interrupt level.
2400  */
2401 void
2402 ppp_output_wakeup(struct ppp_channel *chan)
2403 {
2404         struct channel *pch = chan->ppp;
2405 
2406         if (!pch)
2407                 return;
2408         ppp_channel_push(pch);
2409 }
2410 
2411 /*
2412  * Compression control.
2413  */
2414 
2415 /* Process the PPPIOCSCOMPRESS ioctl. */
2416 static int
2417 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2418 {
2419         int err;
2420         struct compressor *cp, *ocomp;
2421         struct ppp_option_data data;
2422         void *state, *ostate;
2423         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2424 
2425         err = -EFAULT;
2426         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2427             (data.length <= CCP_MAX_OPTION_LENGTH &&
2428              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2429                 goto out;
2430         err = -EINVAL;
2431         if (data.length > CCP_MAX_OPTION_LENGTH ||
2432             ccp_option[1] < 2 || ccp_option[1] > data.length)
2433                 goto out;
2434 
2435         cp = try_then_request_module(
2436                 find_compressor(ccp_option[0]),
2437                 "ppp-compress-%d", ccp_option[0]);
2438         if (!cp)
2439                 goto out;
2440 
2441         err = -ENOBUFS;
2442         if (data.transmit) {
2443                 state = cp->comp_alloc(ccp_option, data.length);
2444                 if (state) {
2445                         ppp_xmit_lock(ppp);
2446                         ppp->xstate &= ~SC_COMP_RUN;
2447                         ocomp = ppp->xcomp;
2448                         ostate = ppp->xc_state;
2449                         ppp->xcomp = cp;
2450                         ppp->xc_state = state;
2451                         ppp_xmit_unlock(ppp);
2452                         if (ostate) {
2453                                 ocomp->comp_free(ostate);
2454                                 module_put(ocomp->owner);
2455                         }
2456                         err = 0;
2457                 } else
2458                         module_put(cp->owner);
2459 
2460         } else {
2461                 state = cp->decomp_alloc(ccp_option, data.length);
2462                 if (state) {
2463                         ppp_recv_lock(ppp);
2464                         ppp->rstate &= ~SC_DECOMP_RUN;
2465                         ocomp = ppp->rcomp;
2466                         ostate = ppp->rc_state;
2467                         ppp->rcomp = cp;
2468                         ppp->rc_state = state;
2469                         ppp_recv_unlock(ppp);
2470                         if (ostate) {
2471                                 ocomp->decomp_free(ostate);
2472                                 module_put(ocomp->owner);
2473                         }
2474                         err = 0;
2475                 } else
2476                         module_put(cp->owner);
2477         }
2478 
2479  out:
2480         return err;
2481 }
2482 
2483 /*
2484  * Look at a CCP packet and update our state accordingly.
2485  * We assume the caller has the xmit or recv path locked.
2486  */
2487 static void
2488 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2489 {
2490         unsigned char *dp;
2491         int len;
2492 
2493         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2494                 return; /* no header */
2495         dp = skb->data + 2;
2496 
2497         switch (CCP_CODE(dp)) {
2498         case CCP_CONFREQ:
2499 
2500                 /* A ConfReq starts negotiation of compression
2501                  * in one direction of transmission,
2502                  * and hence brings it down...but which way?
2503                  *
2504                  * Remember:
2505                  * A ConfReq indicates what the sender would like to receive
2506                  */
2507                 if(inbound)
2508                         /* He is proposing what I should send */
2509                         ppp->xstate &= ~SC_COMP_RUN;
2510                 else
2511                         /* I am proposing to what he should send */
2512                         ppp->rstate &= ~SC_DECOMP_RUN;
2513 
2514                 break;
2515 
2516         case CCP_TERMREQ:
2517         case CCP_TERMACK:
2518                 /*
2519                  * CCP is going down, both directions of transmission
2520                  */
2521                 ppp->rstate &= ~SC_DECOMP_RUN;
2522                 ppp->xstate &= ~SC_COMP_RUN;
2523                 break;
2524 
2525         case CCP_CONFACK:
2526                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2527                         break;
2528                 len = CCP_LENGTH(dp);
2529                 if (!pskb_may_pull(skb, len + 2))
2530                         return;         /* too short */
2531                 dp += CCP_HDRLEN;
2532                 len -= CCP_HDRLEN;
2533                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2534                         break;
2535                 if (inbound) {
2536                         /* we will start receiving compressed packets */
2537                         if (!ppp->rc_state)
2538                                 break;
2539                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2540                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2541                                 ppp->rstate |= SC_DECOMP_RUN;
2542                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2543                         }
2544                 } else {
2545                         /* we will soon start sending compressed packets */
2546                         if (!ppp->xc_state)
2547                                 break;
2548                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2549                                         ppp->file.index, 0, ppp->debug))
2550                                 ppp->xstate |= SC_COMP_RUN;
2551                 }
2552                 break;
2553 
2554         case CCP_RESETACK:
2555                 /* reset the [de]compressor */
2556                 if ((ppp->flags & SC_CCP_UP) == 0)
2557                         break;
2558                 if (inbound) {
2559                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2560                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2561                                 ppp->rstate &= ~SC_DC_ERROR;
2562                         }
2563                 } else {
2564                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2565                                 ppp->xcomp->comp_reset(ppp->xc_state);
2566                 }
2567                 break;
2568         }
2569 }
2570 
2571 /* Free up compression resources. */
2572 static void
2573 ppp_ccp_closed(struct ppp *ppp)
2574 {
2575         void *xstate, *rstate;
2576         struct compressor *xcomp, *rcomp;
2577 
2578         ppp_lock(ppp);
2579         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2580         ppp->xstate = 0;
2581         xcomp = ppp->xcomp;
2582         xstate = ppp->xc_state;
2583         ppp->xc_state = NULL;
2584         ppp->rstate = 0;
2585         rcomp = ppp->rcomp;
2586         rstate = ppp->rc_state;
2587         ppp->rc_state = NULL;
2588         ppp_unlock(ppp);
2589 
2590         if (xstate) {
2591                 xcomp->comp_free(xstate);
2592                 module_put(xcomp->owner);
2593         }
2594         if (rstate) {
2595                 rcomp->decomp_free(rstate);
2596                 module_put(rcomp->owner);
2597         }
2598 }
2599 
2600 /* List of compressors. */
2601 static LIST_HEAD(compressor_list);
2602 static DEFINE_SPINLOCK(compressor_list_lock);
2603 
2604 struct compressor_entry {
2605         struct list_head list;
2606         struct compressor *comp;
2607 };
2608 
2609 static struct compressor_entry *
2610 find_comp_entry(int proto)
2611 {
2612         struct compressor_entry *ce;
2613 
2614         list_for_each_entry(ce, &compressor_list, list) {
2615                 if (ce->comp->compress_proto == proto)
2616                         return ce;
2617         }
2618         return NULL;
2619 }
2620 
2621 /* Register a compressor */
2622 int
2623 ppp_register_compressor(struct compressor *cp)
2624 {
2625         struct compressor_entry *ce;
2626         int ret;
2627         spin_lock(&compressor_list_lock);
2628         ret = -EEXIST;
2629         if (find_comp_entry(cp->compress_proto))
2630                 goto out;
2631         ret = -ENOMEM;
2632         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2633         if (!ce)
2634                 goto out;
2635         ret = 0;
2636         ce->comp = cp;
2637         list_add(&ce->list, &compressor_list);
2638  out:
2639         spin_unlock(&compressor_list_lock);
2640         return ret;
2641 }
2642 
2643 /* Unregister a compressor */
2644 void
2645 ppp_unregister_compressor(struct compressor *cp)
2646 {
2647         struct compressor_entry *ce;
2648 
2649         spin_lock(&compressor_list_lock);
2650         ce = find_comp_entry(cp->compress_proto);
2651         if (ce && ce->comp == cp) {
2652                 list_del(&ce->list);
2653                 kfree(ce);
2654         }
2655         spin_unlock(&compressor_list_lock);
2656 }
2657 
2658 /* Find a compressor. */
2659 static struct compressor *
2660 find_compressor(int type)
2661 {
2662         struct compressor_entry *ce;
2663         struct compressor *cp = NULL;
2664 
2665         spin_lock(&compressor_list_lock);
2666         ce = find_comp_entry(type);
2667         if (ce) {
2668                 cp = ce->comp;
2669                 if (!try_module_get(cp->owner))
2670                         cp = NULL;
2671         }
2672         spin_unlock(&compressor_list_lock);
2673         return cp;
2674 }
2675 
2676 /*
2677  * Miscelleneous stuff.
2678  */
2679 
2680 static void
2681 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2682 {
2683         struct slcompress *vj = ppp->vj;
2684 
2685         memset(st, 0, sizeof(*st));
2686         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2687         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2688         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2689         st->p.ppp_opackets = ppp->stats64.tx_packets;
2690         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2691         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2692         if (!vj)
2693                 return;
2694         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2695         st->vj.vjs_compressed = vj->sls_o_compressed;
2696         st->vj.vjs_searches = vj->sls_o_searches;
2697         st->vj.vjs_misses = vj->sls_o_misses;
2698         st->vj.vjs_errorin = vj->sls_i_error;
2699         st->vj.vjs_tossed = vj->sls_i_tossed;
2700         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2701         st->vj.vjs_compressedin = vj->sls_i_compressed;
2702 }
2703 
2704 /*
2705  * Stuff for handling the lists of ppp units and channels
2706  * and for initialization.
2707  */
2708 
2709 /*
2710  * Create a new ppp interface unit.  Fails if it can't allocate memory
2711  * or if there is already a unit with the requested number.
2712  * unit == -1 means allocate a new number.
2713  */
2714 static struct ppp *ppp_create_interface(struct net *net, int unit,
2715                                         struct file *file, int *retp)
2716 {
2717         struct ppp *ppp;
2718         struct ppp_net *pn;
2719         struct net_device *dev = NULL;
2720         int ret = -ENOMEM;
2721         int i;
2722 
2723         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_UNKNOWN,
2724                            ppp_setup);
2725         if (!dev)
2726                 goto out1;
2727 
2728         pn = ppp_pernet(net);
2729 
2730         ppp = netdev_priv(dev);
2731         ppp->dev = dev;
2732         ppp->mru = PPP_MRU;
2733         init_ppp_file(&ppp->file, INTERFACE);
2734         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2735         ppp->owner = file;
2736         for (i = 0; i < NUM_NP; ++i)
2737                 ppp->npmode[i] = NPMODE_PASS;
2738         INIT_LIST_HEAD(&ppp->channels);
2739         spin_lock_init(&ppp->rlock);
2740         spin_lock_init(&ppp->wlock);
2741 #ifdef CONFIG_PPP_MULTILINK
2742         ppp->minseq = -1;
2743         skb_queue_head_init(&ppp->mrq);
2744 #endif /* CONFIG_PPP_MULTILINK */
2745 #ifdef CONFIG_PPP_FILTER
2746         ppp->pass_filter = NULL;
2747         ppp->active_filter = NULL;
2748 #endif /* CONFIG_PPP_FILTER */
2749 
2750         /*
2751          * drum roll: don't forget to set
2752          * the net device is belong to
2753          */
2754         dev_net_set(dev, net);
2755 
2756         rtnl_lock();
2757         mutex_lock(&pn->all_ppp_mutex);
2758 
2759         if (unit < 0) {
2760                 unit = unit_get(&pn->units_idr, ppp);
2761                 if (unit < 0) {
2762                         ret = unit;
2763                         goto out2;
2764                 }
2765         } else {
2766                 ret = -EEXIST;
2767                 if (unit_find(&pn->units_idr, unit))
2768                         goto out2; /* unit already exists */
2769                 /*
2770                  * if caller need a specified unit number
2771                  * lets try to satisfy him, otherwise --
2772                  * he should better ask us for new unit number
2773                  *
2774                  * NOTE: yes I know that returning EEXIST it's not
2775                  * fair but at least pppd will ask us to allocate
2776                  * new unit in this case so user is happy :)
2777                  */
2778                 unit = unit_set(&pn->units_idr, ppp, unit);
2779                 if (unit < 0)
2780                         goto out2;
2781         }
2782 
2783         /* Initialize the new ppp unit */
2784         ppp->file.index = unit;
2785         sprintf(dev->name, "ppp%d", unit);
2786 
2787         ret = register_netdevice(dev);
2788         if (ret != 0) {
2789                 unit_put(&pn->units_idr, unit);
2790                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2791                            dev->name, ret);
2792                 goto out2;
2793         }
2794 
2795         ppp->ppp_net = net;
2796 
2797         atomic_inc(&ppp_unit_count);
2798         mutex_unlock(&pn->all_ppp_mutex);
2799         rtnl_unlock();
2800 
2801         *retp = 0;
2802         return ppp;
2803 
2804 out2:
2805         mutex_unlock(&pn->all_ppp_mutex);
2806         free_netdev(dev);
2807 out1:
2808         *retp = ret;
2809         return NULL;
2810 }
2811 
2812 /*
2813  * Initialize a ppp_file structure.
2814  */
2815 static void
2816 init_ppp_file(struct ppp_file *pf, int kind)
2817 {
2818         pf->kind = kind;
2819         skb_queue_head_init(&pf->xq);
2820         skb_queue_head_init(&pf->rq);
2821         atomic_set(&pf->refcnt, 1);
2822         init_waitqueue_head(&pf->rwait);
2823 }
2824 
2825 /*
2826  * Free the memory used by a ppp unit.  This is only called once
2827  * there are no channels connected to the unit and no file structs
2828  * that reference the unit.
2829  */
2830 static void ppp_destroy_interface(struct ppp *ppp)
2831 {
2832         atomic_dec(&ppp_unit_count);
2833 
2834         if (!ppp->file.dead || ppp->n_channels) {
2835                 /* "can't happen" */
2836                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2837                            "but dead=%d n_channels=%d !\n",
2838                            ppp, ppp->file.dead, ppp->n_channels);
2839                 return;
2840         }
2841 
2842         ppp_ccp_closed(ppp);
2843         if (ppp->vj) {
2844                 slhc_free(ppp->vj);
2845                 ppp->vj = NULL;
2846         }
2847         skb_queue_purge(&ppp->file.xq);
2848         skb_queue_purge(&ppp->file.rq);
2849 #ifdef CONFIG_PPP_MULTILINK
2850         skb_queue_purge(&ppp->mrq);
2851 #endif /* CONFIG_PPP_MULTILINK */
2852 #ifdef CONFIG_PPP_FILTER
2853         if (ppp->pass_filter) {
2854                 bpf_prog_destroy(ppp->pass_filter);
2855                 ppp->pass_filter = NULL;
2856         }
2857 
2858         if (ppp->active_filter) {
2859                 bpf_prog_destroy(ppp->active_filter);
2860                 ppp->active_filter = NULL;
2861         }
2862 #endif /* CONFIG_PPP_FILTER */
2863 
2864         kfree_skb(ppp->xmit_pending);
2865 
2866         free_netdev(ppp->dev);
2867 }
2868 
2869 /*
2870  * Locate an existing ppp unit.
2871  * The caller should have locked the all_ppp_mutex.
2872  */
2873 static struct ppp *
2874 ppp_find_unit(struct ppp_net *pn, int unit)
2875 {
2876         return unit_find(&pn->units_idr, unit);
2877 }
2878 
2879 /*
2880  * Locate an existing ppp channel.
2881  * The caller should have locked the all_channels_lock.
2882  * First we look in the new_channels list, then in the
2883  * all_channels list.  If found in the new_channels list,
2884  * we move it to the all_channels list.  This is for speed
2885  * when we have a lot of channels in use.
2886  */
2887 static struct channel *
2888 ppp_find_channel(struct ppp_net *pn, int unit)
2889 {
2890         struct channel *pch;
2891 
2892         list_for_each_entry(pch, &pn->new_channels, list) {
2893                 if (pch->file.index == unit) {
2894                         list_move(&pch->list, &pn->all_channels);
2895                         return pch;
2896                 }
2897         }
2898 
2899         list_for_each_entry(pch, &pn->all_channels, list) {
2900                 if (pch->file.index == unit)
2901                         return pch;
2902         }
2903 
2904         return NULL;
2905 }
2906 
2907 /*
2908  * Connect a PPP channel to a PPP interface unit.
2909  */
2910 static int
2911 ppp_connect_channel(struct channel *pch, int unit)
2912 {
2913         struct ppp *ppp;
2914         struct ppp_net *pn;
2915         int ret = -ENXIO;
2916         int hdrlen;
2917 
2918         pn = ppp_pernet(pch->chan_net);
2919 
2920         mutex_lock(&pn->all_ppp_mutex);
2921         ppp = ppp_find_unit(pn, unit);
2922         if (!ppp)
2923                 goto out;
2924         write_lock_bh(&pch->upl);
2925         ret = -EINVAL;
2926         if (pch->ppp)
2927                 goto outl;
2928 
2929         ppp_lock(ppp);
2930         if (pch->file.hdrlen > ppp->file.hdrlen)
2931                 ppp->file.hdrlen = pch->file.hdrlen;
2932         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2933         if (hdrlen > ppp->dev->hard_header_len)
2934                 ppp->dev->hard_header_len = hdrlen;
2935         list_add_tail(&pch->clist, &ppp->channels);
2936         ++ppp->n_channels;
2937         pch->ppp = ppp;
2938         atomic_inc(&ppp->file.refcnt);
2939         ppp_unlock(ppp);
2940         ret = 0;
2941 
2942  outl:
2943         write_unlock_bh(&pch->upl);
2944  out:
2945         mutex_unlock(&pn->all_ppp_mutex);
2946         return ret;
2947 }
2948 
2949 /*
2950  * Disconnect a channel from its ppp unit.
2951  */
2952 static int
2953 ppp_disconnect_channel(struct channel *pch)
2954 {
2955         struct ppp *ppp;
2956         int err = -EINVAL;
2957 
2958         write_lock_bh(&pch->upl);
2959         ppp = pch->ppp;
2960         pch->ppp = NULL;
2961         write_unlock_bh(&pch->upl);
2962         if (ppp) {
2963                 /* remove it from the ppp unit's list */
2964                 ppp_lock(ppp);
2965                 list_del(&pch->clist);
2966                 if (--ppp->n_channels == 0)
2967                         wake_up_interruptible(&ppp->file.rwait);
2968                 ppp_unlock(ppp);
2969                 if (atomic_dec_and_test(&ppp->file.refcnt))
2970                         ppp_destroy_interface(ppp);
2971                 err = 0;
2972         }
2973         return err;
2974 }
2975 
2976 /*
2977  * Free up the resources used by a ppp channel.
2978  */
2979 static void ppp_destroy_channel(struct channel *pch)
2980 {
2981         atomic_dec(&channel_count);
2982 
2983         if (!pch->file.dead) {
2984                 /* "can't happen" */
2985                 pr_err("ppp: destroying undead channel %p !\n", pch);
2986                 return;
2987         }
2988         skb_queue_purge(&pch->file.xq);
2989         skb_queue_purge(&pch->file.rq);
2990         kfree(pch);
2991 }
2992 
2993 static void __exit ppp_cleanup(void)
2994 {
2995         /* should never happen */
2996         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2997                 pr_err("PPP: removing module but units remain!\n");
2998         unregister_chrdev(PPP_MAJOR, "ppp");
2999         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3000         class_destroy(ppp_class);
3001         unregister_pernet_device(&ppp_net_ops);
3002 }
3003 
3004 /*
3005  * Units handling. Caller must protect concurrent access
3006  * by holding all_ppp_mutex
3007  */
3008 
3009 /* associate pointer with specified number */
3010 static int unit_set(struct idr *p, void *ptr, int n)
3011 {
3012         int unit;
3013 
3014         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3015         if (unit == -ENOSPC)
3016                 unit = -EINVAL;
3017         return unit;
3018 }
3019 
3020 /* get new free unit number and associate pointer with it */
3021 static int unit_get(struct idr *p, void *ptr)
3022 {
3023         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3024 }
3025 
3026 /* put unit number back to a pool */
3027 static void unit_put(struct idr *p, int n)
3028 {
3029         idr_remove(p, n);
3030 }
3031 
3032 /* get pointer associated with the number */
3033 static void *unit_find(struct idr *p, int n)
3034 {
3035         return idr_find(p, n);
3036 }
3037 
3038 /* Module/initialization stuff */
3039 
3040 module_init(ppp_init);
3041 module_exit(ppp_cleanup);
3042 
3043 EXPORT_SYMBOL(ppp_register_net_channel);
3044 EXPORT_SYMBOL(ppp_register_channel);
3045 EXPORT_SYMBOL(ppp_unregister_channel);
3046 EXPORT_SYMBOL(ppp_channel_index);
3047 EXPORT_SYMBOL(ppp_unit_number);
3048 EXPORT_SYMBOL(ppp_dev_name);
3049 EXPORT_SYMBOL(ppp_input);
3050 EXPORT_SYMBOL(ppp_input_error);
3051 EXPORT_SYMBOL(ppp_output_wakeup);
3052 EXPORT_SYMBOL(ppp_register_compressor);
3053 EXPORT_SYMBOL(ppp_unregister_compressor);
3054 MODULE_LICENSE("GPL");
3055 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3056 MODULE_ALIAS("devname:ppp");
3057 

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