Version:  2.0.40 2.2.26 2.4.37 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 4.5 4.6

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 
447                         ppp_recv_lock(ppp);
448                         if (ppp->n_channels == 0 &&
449                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
450                                 ppp_recv_unlock(ppp);
451                                 break;
452                         }
453                         ppp_recv_unlock(ppp);
454                 }
455                 ret = -EAGAIN;
456                 if (file->f_flags & O_NONBLOCK)
457                         break;
458                 ret = -ERESTARTSYS;
459                 if (signal_pending(current))
460                         break;
461                 schedule();
462         }
463         set_current_state(TASK_RUNNING);
464         remove_wait_queue(&pf->rwait, &wait);
465 
466         if (!skb)
467                 goto out;
468 
469         ret = -EOVERFLOW;
470         if (skb->len > count)
471                 goto outf;
472         ret = -EFAULT;
473         iov.iov_base = buf;
474         iov.iov_len = count;
475         iov_iter_init(&to, READ, &iov, 1, count);
476         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
477                 goto outf;
478         ret = skb->len;
479 
480  outf:
481         kfree_skb(skb);
482  out:
483         return ret;
484 }
485 
486 static ssize_t ppp_write(struct file *file, const char __user *buf,
487                          size_t count, loff_t *ppos)
488 {
489         struct ppp_file *pf = file->private_data;
490         struct sk_buff *skb;
491         ssize_t ret;
492 
493         if (!pf)
494                 return -ENXIO;
495         ret = -ENOMEM;
496         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
497         if (!skb)
498                 goto out;
499         skb_reserve(skb, pf->hdrlen);
500         ret = -EFAULT;
501         if (copy_from_user(skb_put(skb, count), buf, count)) {
502                 kfree_skb(skb);
503                 goto out;
504         }
505 
506         skb_queue_tail(&pf->xq, skb);
507 
508         switch (pf->kind) {
509         case INTERFACE:
510                 ppp_xmit_process(PF_TO_PPP(pf));
511                 break;
512         case CHANNEL:
513                 ppp_channel_push(PF_TO_CHANNEL(pf));
514                 break;
515         }
516 
517         ret = count;
518 
519  out:
520         return ret;
521 }
522 
523 /* No kernel lock - fine */
524 static unsigned int ppp_poll(struct file *file, poll_table *wait)
525 {
526         struct ppp_file *pf = file->private_data;
527         unsigned int mask;
528 
529         if (!pf)
530                 return 0;
531         poll_wait(file, &pf->rwait, wait);
532         mask = POLLOUT | POLLWRNORM;
533         if (skb_peek(&pf->rq))
534                 mask |= POLLIN | POLLRDNORM;
535         if (pf->dead)
536                 mask |= POLLHUP;
537         else if (pf->kind == INTERFACE) {
538                 /* see comment in ppp_read */
539                 struct ppp *ppp = PF_TO_PPP(pf);
540 
541                 ppp_recv_lock(ppp);
542                 if (ppp->n_channels == 0 &&
543                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
544                         mask |= POLLIN | POLLRDNORM;
545                 ppp_recv_unlock(ppp);
546         }
547 
548         return mask;
549 }
550 
551 #ifdef CONFIG_PPP_FILTER
552 static int get_filter(void __user *arg, struct sock_filter **p)
553 {
554         struct sock_fprog uprog;
555         struct sock_filter *code = NULL;
556         int len;
557 
558         if (copy_from_user(&uprog, arg, sizeof(uprog)))
559                 return -EFAULT;
560 
561         if (!uprog.len) {
562                 *p = NULL;
563                 return 0;
564         }
565 
566         len = uprog.len * sizeof(struct sock_filter);
567         code = memdup_user(uprog.filter, len);
568         if (IS_ERR(code))
569                 return PTR_ERR(code);
570 
571         *p = code;
572         return uprog.len;
573 }
574 #endif /* CONFIG_PPP_FILTER */
575 
576 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
577 {
578         struct ppp_file *pf;
579         struct ppp *ppp;
580         int err = -EFAULT, val, val2, i;
581         struct ppp_idle idle;
582         struct npioctl npi;
583         int unit, cflags;
584         struct slcompress *vj;
585         void __user *argp = (void __user *)arg;
586         int __user *p = argp;
587 
588         mutex_lock(&ppp_mutex);
589 
590         pf = file->private_data;
591         if (!pf) {
592                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
593                                            pf, file, cmd, arg);
594                 goto out;
595         }
596 
597         if (cmd == PPPIOCDETACH) {
598                 /*
599                  * We have to be careful here... if the file descriptor
600                  * has been dup'd, we could have another process in the
601                  * middle of a poll using the same file *, so we had
602                  * better not free the interface data structures -
603                  * instead we fail the ioctl.  Even in this case, we
604                  * shut down the interface if we are the owner of it.
605                  * Actually, we should get rid of PPPIOCDETACH, userland
606                  * (i.e. pppd) could achieve the same effect by closing
607                  * this fd and reopening /dev/ppp.
608                  */
609                 err = -EINVAL;
610                 if (pf->kind == INTERFACE) {
611                         ppp = PF_TO_PPP(pf);
612                         rtnl_lock();
613                         if (file == ppp->owner)
614                                 unregister_netdevice(ppp->dev);
615                         rtnl_unlock();
616                 }
617                 if (atomic_long_read(&file->f_count) < 2) {
618                         ppp_release(NULL, file);
619                         err = 0;
620                 } else
621                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
622                                 atomic_long_read(&file->f_count));
623                 goto out;
624         }
625 
626         if (pf->kind == CHANNEL) {
627                 struct channel *pch;
628                 struct ppp_channel *chan;
629 
630                 pch = PF_TO_CHANNEL(pf);
631 
632                 switch (cmd) {
633                 case PPPIOCCONNECT:
634                         if (get_user(unit, p))
635                                 break;
636                         err = ppp_connect_channel(pch, unit);
637                         break;
638 
639                 case PPPIOCDISCONN:
640                         err = ppp_disconnect_channel(pch);
641                         break;
642 
643                 default:
644                         down_read(&pch->chan_sem);
645                         chan = pch->chan;
646                         err = -ENOTTY;
647                         if (chan && chan->ops->ioctl)
648                                 err = chan->ops->ioctl(chan, cmd, arg);
649                         up_read(&pch->chan_sem);
650                 }
651                 goto out;
652         }
653 
654         if (pf->kind != INTERFACE) {
655                 /* can't happen */
656                 pr_err("PPP: not interface or channel??\n");
657                 err = -EINVAL;
658                 goto out;
659         }
660 
661         ppp = PF_TO_PPP(pf);
662         switch (cmd) {
663         case PPPIOCSMRU:
664                 if (get_user(val, p))
665                         break;
666                 ppp->mru = val;
667                 err = 0;
668                 break;
669 
670         case PPPIOCSFLAGS:
671                 if (get_user(val, p))
672                         break;
673                 ppp_lock(ppp);
674                 cflags = ppp->flags & ~val;
675 #ifdef CONFIG_PPP_MULTILINK
676                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
677                         ppp->nextseq = 0;
678 #endif
679                 ppp->flags = val & SC_FLAG_BITS;
680                 ppp_unlock(ppp);
681                 if (cflags & SC_CCP_OPEN)
682                         ppp_ccp_closed(ppp);
683                 err = 0;
684                 break;
685 
686         case PPPIOCGFLAGS:
687                 val = ppp->flags | ppp->xstate | ppp->rstate;
688                 if (put_user(val, p))
689                         break;
690                 err = 0;
691                 break;
692 
693         case PPPIOCSCOMPRESS:
694                 err = ppp_set_compress(ppp, arg);
695                 break;
696 
697         case PPPIOCGUNIT:
698                 if (put_user(ppp->file.index, p))
699                         break;
700                 err = 0;
701                 break;
702 
703         case PPPIOCSDEBUG:
704                 if (get_user(val, p))
705                         break;
706                 ppp->debug = val;
707                 err = 0;
708                 break;
709 
710         case PPPIOCGDEBUG:
711                 if (put_user(ppp->debug, p))
712                         break;
713                 err = 0;
714                 break;
715 
716         case PPPIOCGIDLE:
717                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
718                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
719                 if (copy_to_user(argp, &idle, sizeof(idle)))
720                         break;
721                 err = 0;
722                 break;
723 
724         case PPPIOCSMAXCID:
725                 if (get_user(val, p))
726                         break;
727                 val2 = 15;
728                 if ((val >> 16) != 0) {
729                         val2 = val >> 16;
730                         val &= 0xffff;
731                 }
732                 vj = slhc_init(val2+1, val+1);
733                 if (IS_ERR(vj)) {
734                         err = PTR_ERR(vj);
735                         break;
736                 }
737                 ppp_lock(ppp);
738                 if (ppp->vj)
739                         slhc_free(ppp->vj);
740                 ppp->vj = vj;
741                 ppp_unlock(ppp);
742                 err = 0;
743                 break;
744 
745         case PPPIOCGNPMODE:
746         case PPPIOCSNPMODE:
747                 if (copy_from_user(&npi, argp, sizeof(npi)))
748                         break;
749                 err = proto_to_npindex(npi.protocol);
750                 if (err < 0)
751                         break;
752                 i = err;
753                 if (cmd == PPPIOCGNPMODE) {
754                         err = -EFAULT;
755                         npi.mode = ppp->npmode[i];
756                         if (copy_to_user(argp, &npi, sizeof(npi)))
757                                 break;
758                 } else {
759                         ppp->npmode[i] = npi.mode;
760                         /* we may be able to transmit more packets now (??) */
761                         netif_wake_queue(ppp->dev);
762                 }
763                 err = 0;
764                 break;
765 
766 #ifdef CONFIG_PPP_FILTER
767         case PPPIOCSPASS:
768         {
769                 struct sock_filter *code;
770 
771                 err = get_filter(argp, &code);
772                 if (err >= 0) {
773                         struct bpf_prog *pass_filter = NULL;
774                         struct sock_fprog_kern fprog = {
775                                 .len = err,
776                                 .filter = code,
777                         };
778 
779                         err = 0;
780                         if (fprog.filter)
781                                 err = bpf_prog_create(&pass_filter, &fprog);
782                         if (!err) {
783                                 ppp_lock(ppp);
784                                 if (ppp->pass_filter)
785                                         bpf_prog_destroy(ppp->pass_filter);
786                                 ppp->pass_filter = pass_filter;
787                                 ppp_unlock(ppp);
788                         }
789                         kfree(code);
790                 }
791                 break;
792         }
793         case PPPIOCSACTIVE:
794         {
795                 struct sock_filter *code;
796 
797                 err = get_filter(argp, &code);
798                 if (err >= 0) {
799                         struct bpf_prog *active_filter = NULL;
800                         struct sock_fprog_kern fprog = {
801                                 .len = err,
802                                 .filter = code,
803                         };
804 
805                         err = 0;
806                         if (fprog.filter)
807                                 err = bpf_prog_create(&active_filter, &fprog);
808                         if (!err) {
809                                 ppp_lock(ppp);
810                                 if (ppp->active_filter)
811                                         bpf_prog_destroy(ppp->active_filter);
812                                 ppp->active_filter = active_filter;
813                                 ppp_unlock(ppp);
814                         }
815                         kfree(code);
816                 }
817                 break;
818         }
819 #endif /* CONFIG_PPP_FILTER */
820 
821 #ifdef CONFIG_PPP_MULTILINK
822         case PPPIOCSMRRU:
823                 if (get_user(val, p))
824                         break;
825                 ppp_recv_lock(ppp);
826                 ppp->mrru = val;
827                 ppp_recv_unlock(ppp);
828                 err = 0;
829                 break;
830 #endif /* CONFIG_PPP_MULTILINK */
831 
832         default:
833                 err = -ENOTTY;
834         }
835 
836 out:
837         mutex_unlock(&ppp_mutex);
838 
839         return err;
840 }
841 
842 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
843                         struct file *file, unsigned int cmd, unsigned long arg)
844 {
845         int unit, err = -EFAULT;
846         struct ppp *ppp;
847         struct channel *chan;
848         struct ppp_net *pn;
849         int __user *p = (int __user *)arg;
850 
851         switch (cmd) {
852         case PPPIOCNEWUNIT:
853                 /* Create a new ppp unit */
854                 if (get_user(unit, p))
855                         break;
856                 ppp = ppp_create_interface(net, unit, file, &err);
857                 if (!ppp)
858                         break;
859                 file->private_data = &ppp->file;
860                 err = -EFAULT;
861                 if (put_user(ppp->file.index, p))
862                         break;
863                 err = 0;
864                 break;
865 
866         case PPPIOCATTACH:
867                 /* Attach to an existing ppp unit */
868                 if (get_user(unit, p))
869                         break;
870                 err = -ENXIO;
871                 pn = ppp_pernet(net);
872                 mutex_lock(&pn->all_ppp_mutex);
873                 ppp = ppp_find_unit(pn, unit);
874                 if (ppp) {
875                         atomic_inc(&ppp->file.refcnt);
876                         file->private_data = &ppp->file;
877                         err = 0;
878                 }
879                 mutex_unlock(&pn->all_ppp_mutex);
880                 break;
881 
882         case PPPIOCATTCHAN:
883                 if (get_user(unit, p))
884                         break;
885                 err = -ENXIO;
886                 pn = ppp_pernet(net);
887                 spin_lock_bh(&pn->all_channels_lock);
888                 chan = ppp_find_channel(pn, unit);
889                 if (chan) {
890                         atomic_inc(&chan->file.refcnt);
891                         file->private_data = &chan->file;
892                         err = 0;
893                 }
894                 spin_unlock_bh(&pn->all_channels_lock);
895                 break;
896 
897         default:
898                 err = -ENOTTY;
899         }
900 
901         return err;
902 }
903 
904 static const struct file_operations ppp_device_fops = {
905         .owner          = THIS_MODULE,
906         .read           = ppp_read,
907         .write          = ppp_write,
908         .poll           = ppp_poll,
909         .unlocked_ioctl = ppp_ioctl,
910         .open           = ppp_open,
911         .release        = ppp_release,
912         .llseek         = noop_llseek,
913 };
914 
915 static __net_init int ppp_init_net(struct net *net)
916 {
917         struct ppp_net *pn = net_generic(net, ppp_net_id);
918 
919         idr_init(&pn->units_idr);
920         mutex_init(&pn->all_ppp_mutex);
921 
922         INIT_LIST_HEAD(&pn->all_channels);
923         INIT_LIST_HEAD(&pn->new_channels);
924 
925         spin_lock_init(&pn->all_channels_lock);
926 
927         return 0;
928 }
929 
930 static __net_exit void ppp_exit_net(struct net *net)
931 {
932         struct ppp_net *pn = net_generic(net, ppp_net_id);
933         struct net_device *dev;
934         struct net_device *aux;
935         struct ppp *ppp;
936         LIST_HEAD(list);
937         int id;
938 
939         rtnl_lock();
940         for_each_netdev_safe(net, dev, aux) {
941                 if (dev->netdev_ops == &ppp_netdev_ops)
942                         unregister_netdevice_queue(dev, &list);
943         }
944 
945         idr_for_each_entry(&pn->units_idr, ppp, id)
946                 /* Skip devices already unregistered by previous loop */
947                 if (!net_eq(dev_net(ppp->dev), net))
948                         unregister_netdevice_queue(ppp->dev, &list);
949 
950         unregister_netdevice_many(&list);
951         rtnl_unlock();
952 
953         idr_destroy(&pn->units_idr);
954 }
955 
956 static struct pernet_operations ppp_net_ops = {
957         .init = ppp_init_net,
958         .exit = ppp_exit_net,
959         .id   = &ppp_net_id,
960         .size = sizeof(struct ppp_net),
961 };
962 
963 #define PPP_MAJOR       108
964 
965 /* Called at boot time if ppp is compiled into the kernel,
966    or at module load time (from init_module) if compiled as a module. */
967 static int __init ppp_init(void)
968 {
969         int err;
970 
971         pr_info("PPP generic driver version " PPP_VERSION "\n");
972 
973         err = register_pernet_device(&ppp_net_ops);
974         if (err) {
975                 pr_err("failed to register PPP pernet device (%d)\n", err);
976                 goto out;
977         }
978 
979         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
980         if (err) {
981                 pr_err("failed to register PPP device (%d)\n", err);
982                 goto out_net;
983         }
984 
985         ppp_class = class_create(THIS_MODULE, "ppp");
986         if (IS_ERR(ppp_class)) {
987                 err = PTR_ERR(ppp_class);
988                 goto out_chrdev;
989         }
990 
991         /* not a big deal if we fail here :-) */
992         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
993 
994         return 0;
995 
996 out_chrdev:
997         unregister_chrdev(PPP_MAJOR, "ppp");
998 out_net:
999         unregister_pernet_device(&ppp_net_ops);
1000 out:
1001         return err;
1002 }
1003 
1004 /*
1005  * Network interface unit routines.
1006  */
1007 static netdev_tx_t
1008 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1009 {
1010         struct ppp *ppp = netdev_priv(dev);
1011         int npi, proto;
1012         unsigned char *pp;
1013 
1014         npi = ethertype_to_npindex(ntohs(skb->protocol));
1015         if (npi < 0)
1016                 goto outf;
1017 
1018         /* Drop, accept or reject the packet */
1019         switch (ppp->npmode[npi]) {
1020         case NPMODE_PASS:
1021                 break;
1022         case NPMODE_QUEUE:
1023                 /* it would be nice to have a way to tell the network
1024                    system to queue this one up for later. */
1025                 goto outf;
1026         case NPMODE_DROP:
1027         case NPMODE_ERROR:
1028                 goto outf;
1029         }
1030 
1031         /* Put the 2-byte PPP protocol number on the front,
1032            making sure there is room for the address and control fields. */
1033         if (skb_cow_head(skb, PPP_HDRLEN))
1034                 goto outf;
1035 
1036         pp = skb_push(skb, 2);
1037         proto = npindex_to_proto[npi];
1038         put_unaligned_be16(proto, pp);
1039 
1040         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1041         skb_queue_tail(&ppp->file.xq, skb);
1042         ppp_xmit_process(ppp);
1043         return NETDEV_TX_OK;
1044 
1045  outf:
1046         kfree_skb(skb);
1047         ++dev->stats.tx_dropped;
1048         return NETDEV_TX_OK;
1049 }
1050 
1051 static int
1052 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1053 {
1054         struct ppp *ppp = netdev_priv(dev);
1055         int err = -EFAULT;
1056         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1057         struct ppp_stats stats;
1058         struct ppp_comp_stats cstats;
1059         char *vers;
1060 
1061         switch (cmd) {
1062         case SIOCGPPPSTATS:
1063                 ppp_get_stats(ppp, &stats);
1064                 if (copy_to_user(addr, &stats, sizeof(stats)))
1065                         break;
1066                 err = 0;
1067                 break;
1068 
1069         case SIOCGPPPCSTATS:
1070                 memset(&cstats, 0, sizeof(cstats));
1071                 if (ppp->xc_state)
1072                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1073                 if (ppp->rc_state)
1074                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1075                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1076                         break;
1077                 err = 0;
1078                 break;
1079 
1080         case SIOCGPPPVER:
1081                 vers = PPP_VERSION;
1082                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1083                         break;
1084                 err = 0;
1085                 break;
1086 
1087         default:
1088                 err = -EINVAL;
1089         }
1090 
1091         return err;
1092 }
1093 
1094 static struct rtnl_link_stats64*
1095 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1096 {
1097         struct ppp *ppp = netdev_priv(dev);
1098 
1099         ppp_recv_lock(ppp);
1100         stats64->rx_packets = ppp->stats64.rx_packets;
1101         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1102         ppp_recv_unlock(ppp);
1103 
1104         ppp_xmit_lock(ppp);
1105         stats64->tx_packets = ppp->stats64.tx_packets;
1106         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1107         ppp_xmit_unlock(ppp);
1108 
1109         stats64->rx_errors        = dev->stats.rx_errors;
1110         stats64->tx_errors        = dev->stats.tx_errors;
1111         stats64->rx_dropped       = dev->stats.rx_dropped;
1112         stats64->tx_dropped       = dev->stats.tx_dropped;
1113         stats64->rx_length_errors = dev->stats.rx_length_errors;
1114 
1115         return stats64;
1116 }
1117 
1118 static struct lock_class_key ppp_tx_busylock;
1119 static int ppp_dev_init(struct net_device *dev)
1120 {
1121         dev->qdisc_tx_busylock = &ppp_tx_busylock;
1122         return 0;
1123 }
1124 
1125 static void ppp_dev_uninit(struct net_device *dev)
1126 {
1127         struct ppp *ppp = netdev_priv(dev);
1128         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1129 
1130         ppp_lock(ppp);
1131         ppp->closing = 1;
1132         ppp_unlock(ppp);
1133 
1134         mutex_lock(&pn->all_ppp_mutex);
1135         unit_put(&pn->units_idr, ppp->file.index);
1136         mutex_unlock(&pn->all_ppp_mutex);
1137 
1138         ppp->owner = NULL;
1139 
1140         ppp->file.dead = 1;
1141         wake_up_interruptible(&ppp->file.rwait);
1142 }
1143 
1144 static const struct net_device_ops ppp_netdev_ops = {
1145         .ndo_init        = ppp_dev_init,
1146         .ndo_uninit      = ppp_dev_uninit,
1147         .ndo_start_xmit  = ppp_start_xmit,
1148         .ndo_do_ioctl    = ppp_net_ioctl,
1149         .ndo_get_stats64 = ppp_get_stats64,
1150 };
1151 
1152 static struct device_type ppp_type = {
1153         .name = "ppp",
1154 };
1155 
1156 static void ppp_setup(struct net_device *dev)
1157 {
1158         dev->netdev_ops = &ppp_netdev_ops;
1159         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1160 
1161         dev->hard_header_len = PPP_HDRLEN;
1162         dev->mtu = PPP_MRU;
1163         dev->addr_len = 0;
1164         dev->tx_queue_len = 3;
1165         dev->type = ARPHRD_PPP;
1166         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1167         netif_keep_dst(dev);
1168 }
1169 
1170 /*
1171  * Transmit-side routines.
1172  */
1173 
1174 /*
1175  * Called to do any work queued up on the transmit side
1176  * that can now be done.
1177  */
1178 static void
1179 ppp_xmit_process(struct ppp *ppp)
1180 {
1181         struct sk_buff *skb;
1182 
1183         ppp_xmit_lock(ppp);
1184         if (!ppp->closing) {
1185                 ppp_push(ppp);
1186                 while (!ppp->xmit_pending &&
1187                        (skb = skb_dequeue(&ppp->file.xq)))
1188                         ppp_send_frame(ppp, skb);
1189                 /* If there's no work left to do, tell the core net
1190                    code that we can accept some more. */
1191                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1192                         netif_wake_queue(ppp->dev);
1193                 else
1194                         netif_stop_queue(ppp->dev);
1195         }
1196         ppp_xmit_unlock(ppp);
1197 }
1198 
1199 static inline struct sk_buff *
1200 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1201 {
1202         struct sk_buff *new_skb;
1203         int len;
1204         int new_skb_size = ppp->dev->mtu +
1205                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1206         int compressor_skb_size = ppp->dev->mtu +
1207                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1208         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1209         if (!new_skb) {
1210                 if (net_ratelimit())
1211                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1212                 return NULL;
1213         }
1214         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1215                 skb_reserve(new_skb,
1216                             ppp->dev->hard_header_len - PPP_HDRLEN);
1217 
1218         /* compressor still expects A/C bytes in hdr */
1219         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1220                                    new_skb->data, skb->len + 2,
1221                                    compressor_skb_size);
1222         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1223                 consume_skb(skb);
1224                 skb = new_skb;
1225                 skb_put(skb, len);
1226                 skb_pull(skb, 2);       /* pull off A/C bytes */
1227         } else if (len == 0) {
1228                 /* didn't compress, or CCP not up yet */
1229                 consume_skb(new_skb);
1230                 new_skb = skb;
1231         } else {
1232                 /*
1233                  * (len < 0)
1234                  * MPPE requires that we do not send unencrypted
1235                  * frames.  The compressor will return -1 if we
1236                  * should drop the frame.  We cannot simply test
1237                  * the compress_proto because MPPE and MPPC share
1238                  * the same number.
1239                  */
1240                 if (net_ratelimit())
1241                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1242                 kfree_skb(skb);
1243                 consume_skb(new_skb);
1244                 new_skb = NULL;
1245         }
1246         return new_skb;
1247 }
1248 
1249 /*
1250  * Compress and send a frame.
1251  * The caller should have locked the xmit path,
1252  * and xmit_pending should be 0.
1253  */
1254 static void
1255 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1256 {
1257         int proto = PPP_PROTO(skb);
1258         struct sk_buff *new_skb;
1259         int len;
1260         unsigned char *cp;
1261 
1262         if (proto < 0x8000) {
1263 #ifdef CONFIG_PPP_FILTER
1264                 /* check if we should pass this packet */
1265                 /* the filter instructions are constructed assuming
1266                    a four-byte PPP header on each packet */
1267                 *skb_push(skb, 2) = 1;
1268                 if (ppp->pass_filter &&
1269                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1270                         if (ppp->debug & 1)
1271                                 netdev_printk(KERN_DEBUG, ppp->dev,
1272                                               "PPP: outbound frame "
1273                                               "not passed\n");
1274                         kfree_skb(skb);
1275                         return;
1276                 }
1277                 /* if this packet passes the active filter, record the time */
1278                 if (!(ppp->active_filter &&
1279                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1280                         ppp->last_xmit = jiffies;
1281                 skb_pull(skb, 2);
1282 #else
1283                 /* for data packets, record the time */
1284                 ppp->last_xmit = jiffies;
1285 #endif /* CONFIG_PPP_FILTER */
1286         }
1287 
1288         ++ppp->stats64.tx_packets;
1289         ppp->stats64.tx_bytes += skb->len - 2;
1290 
1291         switch (proto) {
1292         case PPP_IP:
1293                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1294                         break;
1295                 /* try to do VJ TCP header compression */
1296                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1297                                     GFP_ATOMIC);
1298                 if (!new_skb) {
1299                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1300                         goto drop;
1301                 }
1302                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1303                 cp = skb->data + 2;
1304                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1305                                     new_skb->data + 2, &cp,
1306                                     !(ppp->flags & SC_NO_TCP_CCID));
1307                 if (cp == skb->data + 2) {
1308                         /* didn't compress */
1309                         consume_skb(new_skb);
1310                 } else {
1311                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1312                                 proto = PPP_VJC_COMP;
1313                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1314                         } else {
1315                                 proto = PPP_VJC_UNCOMP;
1316                                 cp[0] = skb->data[2];
1317                         }
1318                         consume_skb(skb);
1319                         skb = new_skb;
1320                         cp = skb_put(skb, len + 2);
1321                         cp[0] = 0;
1322                         cp[1] = proto;
1323                 }
1324                 break;
1325 
1326         case PPP_CCP:
1327                 /* peek at outbound CCP frames */
1328                 ppp_ccp_peek(ppp, skb, 0);
1329                 break;
1330         }
1331 
1332         /* try to do packet compression */
1333         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1334             proto != PPP_LCP && proto != PPP_CCP) {
1335                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1336                         if (net_ratelimit())
1337                                 netdev_err(ppp->dev,
1338                                            "ppp: compression required but "
1339                                            "down - pkt dropped.\n");
1340                         goto drop;
1341                 }
1342                 skb = pad_compress_skb(ppp, skb);
1343                 if (!skb)
1344                         goto drop;
1345         }
1346 
1347         /*
1348          * If we are waiting for traffic (demand dialling),
1349          * queue it up for pppd to receive.
1350          */
1351         if (ppp->flags & SC_LOOP_TRAFFIC) {
1352                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1353                         goto drop;
1354                 skb_queue_tail(&ppp->file.rq, skb);
1355                 wake_up_interruptible(&ppp->file.rwait);
1356                 return;
1357         }
1358 
1359         ppp->xmit_pending = skb;
1360         ppp_push(ppp);
1361         return;
1362 
1363  drop:
1364         kfree_skb(skb);
1365         ++ppp->dev->stats.tx_errors;
1366 }
1367 
1368 /*
1369  * Try to send the frame in xmit_pending.
1370  * The caller should have the xmit path locked.
1371  */
1372 static void
1373 ppp_push(struct ppp *ppp)
1374 {
1375         struct list_head *list;
1376         struct channel *pch;
1377         struct sk_buff *skb = ppp->xmit_pending;
1378 
1379         if (!skb)
1380                 return;
1381 
1382         list = &ppp->channels;
1383         if (list_empty(list)) {
1384                 /* nowhere to send the packet, just drop it */
1385                 ppp->xmit_pending = NULL;
1386                 kfree_skb(skb);
1387                 return;
1388         }
1389 
1390         if ((ppp->flags & SC_MULTILINK) == 0) {
1391                 /* not doing multilink: send it down the first channel */
1392                 list = list->next;
1393                 pch = list_entry(list, struct channel, clist);
1394 
1395                 spin_lock_bh(&pch->downl);
1396                 if (pch->chan) {
1397                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1398                                 ppp->xmit_pending = NULL;
1399                 } else {
1400                         /* channel got unregistered */
1401                         kfree_skb(skb);
1402                         ppp->xmit_pending = NULL;
1403                 }
1404                 spin_unlock_bh(&pch->downl);
1405                 return;
1406         }
1407 
1408 #ifdef CONFIG_PPP_MULTILINK
1409         /* Multilink: fragment the packet over as many links
1410            as can take the packet at the moment. */
1411         if (!ppp_mp_explode(ppp, skb))
1412                 return;
1413 #endif /* CONFIG_PPP_MULTILINK */
1414 
1415         ppp->xmit_pending = NULL;
1416         kfree_skb(skb);
1417 }
1418 
1419 #ifdef CONFIG_PPP_MULTILINK
1420 static bool mp_protocol_compress __read_mostly = true;
1421 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1422 MODULE_PARM_DESC(mp_protocol_compress,
1423                  "compress protocol id in multilink fragments");
1424 
1425 /*
1426  * Divide a packet to be transmitted into fragments and
1427  * send them out the individual links.
1428  */
1429 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1430 {
1431         int len, totlen;
1432         int i, bits, hdrlen, mtu;
1433         int flen;
1434         int navail, nfree, nzero;
1435         int nbigger;
1436         int totspeed;
1437         int totfree;
1438         unsigned char *p, *q;
1439         struct list_head *list;
1440         struct channel *pch;
1441         struct sk_buff *frag;
1442         struct ppp_channel *chan;
1443 
1444         totspeed = 0; /*total bitrate of the bundle*/
1445         nfree = 0; /* # channels which have no packet already queued */
1446         navail = 0; /* total # of usable channels (not deregistered) */
1447         nzero = 0; /* number of channels with zero speed associated*/
1448         totfree = 0; /*total # of channels available and
1449                                   *having no queued packets before
1450                                   *starting the fragmentation*/
1451 
1452         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1453         i = 0;
1454         list_for_each_entry(pch, &ppp->channels, clist) {
1455                 if (pch->chan) {
1456                         pch->avail = 1;
1457                         navail++;
1458                         pch->speed = pch->chan->speed;
1459                 } else {
1460                         pch->avail = 0;
1461                 }
1462                 if (pch->avail) {
1463                         if (skb_queue_empty(&pch->file.xq) ||
1464                                 !pch->had_frag) {
1465                                         if (pch->speed == 0)
1466                                                 nzero++;
1467                                         else
1468                                                 totspeed += pch->speed;
1469 
1470                                         pch->avail = 2;
1471                                         ++nfree;
1472                                         ++totfree;
1473                                 }
1474                         if (!pch->had_frag && i < ppp->nxchan)
1475                                 ppp->nxchan = i;
1476                 }
1477                 ++i;
1478         }
1479         /*
1480          * Don't start sending this packet unless at least half of
1481          * the channels are free.  This gives much better TCP
1482          * performance if we have a lot of channels.
1483          */
1484         if (nfree == 0 || nfree < navail / 2)
1485                 return 0; /* can't take now, leave it in xmit_pending */
1486 
1487         /* Do protocol field compression */
1488         p = skb->data;
1489         len = skb->len;
1490         if (*p == 0 && mp_protocol_compress) {
1491                 ++p;
1492                 --len;
1493         }
1494 
1495         totlen = len;
1496         nbigger = len % nfree;
1497 
1498         /* skip to the channel after the one we last used
1499            and start at that one */
1500         list = &ppp->channels;
1501         for (i = 0; i < ppp->nxchan; ++i) {
1502                 list = list->next;
1503                 if (list == &ppp->channels) {
1504                         i = 0;
1505                         break;
1506                 }
1507         }
1508 
1509         /* create a fragment for each channel */
1510         bits = B;
1511         while (len > 0) {
1512                 list = list->next;
1513                 if (list == &ppp->channels) {
1514                         i = 0;
1515                         continue;
1516                 }
1517                 pch = list_entry(list, struct channel, clist);
1518                 ++i;
1519                 if (!pch->avail)
1520                         continue;
1521 
1522                 /*
1523                  * Skip this channel if it has a fragment pending already and
1524                  * we haven't given a fragment to all of the free channels.
1525                  */
1526                 if (pch->avail == 1) {
1527                         if (nfree > 0)
1528                                 continue;
1529                 } else {
1530                         pch->avail = 1;
1531                 }
1532 
1533                 /* check the channel's mtu and whether it is still attached. */
1534                 spin_lock_bh(&pch->downl);
1535                 if (pch->chan == NULL) {
1536                         /* can't use this channel, it's being deregistered */
1537                         if (pch->speed == 0)
1538                                 nzero--;
1539                         else
1540                                 totspeed -= pch->speed;
1541 
1542                         spin_unlock_bh(&pch->downl);
1543                         pch->avail = 0;
1544                         totlen = len;
1545                         totfree--;
1546                         nfree--;
1547                         if (--navail == 0)
1548                                 break;
1549                         continue;
1550                 }
1551 
1552                 /*
1553                 *if the channel speed is not set divide
1554                 *the packet evenly among the free channels;
1555                 *otherwise divide it according to the speed
1556                 *of the channel we are going to transmit on
1557                 */
1558                 flen = len;
1559                 if (nfree > 0) {
1560                         if (pch->speed == 0) {
1561                                 flen = len/nfree;
1562                                 if (nbigger > 0) {
1563                                         flen++;
1564                                         nbigger--;
1565                                 }
1566                         } else {
1567                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1568                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1569                                 if (nbigger > 0) {
1570                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1571                                         nbigger -= ((totfree - nzero)*pch->speed)/
1572                                                         totspeed;
1573                                 }
1574                         }
1575                         nfree--;
1576                 }
1577 
1578                 /*
1579                  *check if we are on the last channel or
1580                  *we exceded the length of the data to
1581                  *fragment
1582                  */
1583                 if ((nfree <= 0) || (flen > len))
1584                         flen = len;
1585                 /*
1586                  *it is not worth to tx on slow channels:
1587                  *in that case from the resulting flen according to the
1588                  *above formula will be equal or less than zero.
1589                  *Skip the channel in this case
1590                  */
1591                 if (flen <= 0) {
1592                         pch->avail = 2;
1593                         spin_unlock_bh(&pch->downl);
1594                         continue;
1595                 }
1596 
1597                 /*
1598                  * hdrlen includes the 2-byte PPP protocol field, but the
1599                  * MTU counts only the payload excluding the protocol field.
1600                  * (RFC1661 Section 2)
1601                  */
1602                 mtu = pch->chan->mtu - (hdrlen - 2);
1603                 if (mtu < 4)
1604                         mtu = 4;
1605                 if (flen > mtu)
1606                         flen = mtu;
1607                 if (flen == len)
1608                         bits |= E;
1609                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1610                 if (!frag)
1611                         goto noskb;
1612                 q = skb_put(frag, flen + hdrlen);
1613 
1614                 /* make the MP header */
1615                 put_unaligned_be16(PPP_MP, q);
1616                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1617                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1618                         q[3] = ppp->nxseq;
1619                 } else {
1620                         q[2] = bits;
1621                         q[3] = ppp->nxseq >> 16;
1622                         q[4] = ppp->nxseq >> 8;
1623                         q[5] = ppp->nxseq;
1624                 }
1625 
1626                 memcpy(q + hdrlen, p, flen);
1627 
1628                 /* try to send it down the channel */
1629                 chan = pch->chan;
1630                 if (!skb_queue_empty(&pch->file.xq) ||
1631                         !chan->ops->start_xmit(chan, frag))
1632                         skb_queue_tail(&pch->file.xq, frag);
1633                 pch->had_frag = 1;
1634                 p += flen;
1635                 len -= flen;
1636                 ++ppp->nxseq;
1637                 bits = 0;
1638                 spin_unlock_bh(&pch->downl);
1639         }
1640         ppp->nxchan = i;
1641 
1642         return 1;
1643 
1644  noskb:
1645         spin_unlock_bh(&pch->downl);
1646         if (ppp->debug & 1)
1647                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1648         ++ppp->dev->stats.tx_errors;
1649         ++ppp->nxseq;
1650         return 1;       /* abandon the frame */
1651 }
1652 #endif /* CONFIG_PPP_MULTILINK */
1653 
1654 /*
1655  * Try to send data out on a channel.
1656  */
1657 static void
1658 ppp_channel_push(struct channel *pch)
1659 {
1660         struct sk_buff *skb;
1661         struct ppp *ppp;
1662 
1663         spin_lock_bh(&pch->downl);
1664         if (pch->chan) {
1665                 while (!skb_queue_empty(&pch->file.xq)) {
1666                         skb = skb_dequeue(&pch->file.xq);
1667                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1668                                 /* put the packet back and try again later */
1669                                 skb_queue_head(&pch->file.xq, skb);
1670                                 break;
1671                         }
1672                 }
1673         } else {
1674                 /* channel got deregistered */
1675                 skb_queue_purge(&pch->file.xq);
1676         }
1677         spin_unlock_bh(&pch->downl);
1678         /* see if there is anything from the attached unit to be sent */
1679         if (skb_queue_empty(&pch->file.xq)) {
1680                 read_lock_bh(&pch->upl);
1681                 ppp = pch->ppp;
1682                 if (ppp)
1683                         ppp_xmit_process(ppp);
1684                 read_unlock_bh(&pch->upl);
1685         }
1686 }
1687 
1688 /*
1689  * Receive-side routines.
1690  */
1691 
1692 struct ppp_mp_skb_parm {
1693         u32             sequence;
1694         u8              BEbits;
1695 };
1696 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1697 
1698 static inline void
1699 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1700 {
1701         ppp_recv_lock(ppp);
1702         if (!ppp->closing)
1703                 ppp_receive_frame(ppp, skb, pch);
1704         else
1705                 kfree_skb(skb);
1706         ppp_recv_unlock(ppp);
1707 }
1708 
1709 void
1710 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1711 {
1712         struct channel *pch = chan->ppp;
1713         int proto;
1714 
1715         if (!pch) {
1716                 kfree_skb(skb);
1717                 return;
1718         }
1719 
1720         read_lock_bh(&pch->upl);
1721         if (!pskb_may_pull(skb, 2)) {
1722                 kfree_skb(skb);
1723                 if (pch->ppp) {
1724                         ++pch->ppp->dev->stats.rx_length_errors;
1725                         ppp_receive_error(pch->ppp);
1726                 }
1727                 goto done;
1728         }
1729 
1730         proto = PPP_PROTO(skb);
1731         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1732                 /* put it on the channel queue */
1733                 skb_queue_tail(&pch->file.rq, skb);
1734                 /* drop old frames if queue too long */
1735                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1736                        (skb = skb_dequeue(&pch->file.rq)))
1737                         kfree_skb(skb);
1738                 wake_up_interruptible(&pch->file.rwait);
1739         } else {
1740                 ppp_do_recv(pch->ppp, skb, pch);
1741         }
1742 
1743 done:
1744         read_unlock_bh(&pch->upl);
1745 }
1746 
1747 /* Put a 0-length skb in the receive queue as an error indication */
1748 void
1749 ppp_input_error(struct ppp_channel *chan, int code)
1750 {
1751         struct channel *pch = chan->ppp;
1752         struct sk_buff *skb;
1753 
1754         if (!pch)
1755                 return;
1756 
1757         read_lock_bh(&pch->upl);
1758         if (pch->ppp) {
1759                 skb = alloc_skb(0, GFP_ATOMIC);
1760                 if (skb) {
1761                         skb->len = 0;           /* probably unnecessary */
1762                         skb->cb[0] = code;
1763                         ppp_do_recv(pch->ppp, skb, pch);
1764                 }
1765         }
1766         read_unlock_bh(&pch->upl);
1767 }
1768 
1769 /*
1770  * We come in here to process a received frame.
1771  * The receive side of the ppp unit is locked.
1772  */
1773 static void
1774 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1775 {
1776         /* note: a 0-length skb is used as an error indication */
1777         if (skb->len > 0) {
1778                 skb_checksum_complete_unset(skb);
1779 #ifdef CONFIG_PPP_MULTILINK
1780                 /* XXX do channel-level decompression here */
1781                 if (PPP_PROTO(skb) == PPP_MP)
1782                         ppp_receive_mp_frame(ppp, skb, pch);
1783                 else
1784 #endif /* CONFIG_PPP_MULTILINK */
1785                         ppp_receive_nonmp_frame(ppp, skb);
1786         } else {
1787                 kfree_skb(skb);
1788                 ppp_receive_error(ppp);
1789         }
1790 }
1791 
1792 static void
1793 ppp_receive_error(struct ppp *ppp)
1794 {
1795         ++ppp->dev->stats.rx_errors;
1796         if (ppp->vj)
1797                 slhc_toss(ppp->vj);
1798 }
1799 
1800 static void
1801 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1802 {
1803         struct sk_buff *ns;
1804         int proto, len, npi;
1805 
1806         /*
1807          * Decompress the frame, if compressed.
1808          * Note that some decompressors need to see uncompressed frames
1809          * that come in as well as compressed frames.
1810          */
1811         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1812             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1813                 skb = ppp_decompress_frame(ppp, skb);
1814 
1815         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1816                 goto err;
1817 
1818         proto = PPP_PROTO(skb);
1819         switch (proto) {
1820         case PPP_VJC_COMP:
1821                 /* decompress VJ compressed packets */
1822                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1823                         goto err;
1824 
1825                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1826                         /* copy to a new sk_buff with more tailroom */
1827                         ns = dev_alloc_skb(skb->len + 128);
1828                         if (!ns) {
1829                                 netdev_err(ppp->dev, "PPP: no memory "
1830                                            "(VJ decomp)\n");
1831                                 goto err;
1832                         }
1833                         skb_reserve(ns, 2);
1834                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1835                         consume_skb(skb);
1836                         skb = ns;
1837                 }
1838                 else
1839                         skb->ip_summed = CHECKSUM_NONE;
1840 
1841                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1842                 if (len <= 0) {
1843                         netdev_printk(KERN_DEBUG, ppp->dev,
1844                                       "PPP: VJ decompression error\n");
1845                         goto err;
1846                 }
1847                 len += 2;
1848                 if (len > skb->len)
1849                         skb_put(skb, len - skb->len);
1850                 else if (len < skb->len)
1851                         skb_trim(skb, len);
1852                 proto = PPP_IP;
1853                 break;
1854 
1855         case PPP_VJC_UNCOMP:
1856                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1857                         goto err;
1858 
1859                 /* Until we fix the decompressor need to make sure
1860                  * data portion is linear.
1861                  */
1862                 if (!pskb_may_pull(skb, skb->len))
1863                         goto err;
1864 
1865                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1866                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1867                         goto err;
1868                 }
1869                 proto = PPP_IP;
1870                 break;
1871 
1872         case PPP_CCP:
1873                 ppp_ccp_peek(ppp, skb, 1);
1874                 break;
1875         }
1876 
1877         ++ppp->stats64.rx_packets;
1878         ppp->stats64.rx_bytes += skb->len - 2;
1879 
1880         npi = proto_to_npindex(proto);
1881         if (npi < 0) {
1882                 /* control or unknown frame - pass it to pppd */
1883                 skb_queue_tail(&ppp->file.rq, skb);
1884                 /* limit queue length by dropping old frames */
1885                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1886                        (skb = skb_dequeue(&ppp->file.rq)))
1887                         kfree_skb(skb);
1888                 /* wake up any process polling or blocking on read */
1889                 wake_up_interruptible(&ppp->file.rwait);
1890 
1891         } else {
1892                 /* network protocol frame - give it to the kernel */
1893 
1894 #ifdef CONFIG_PPP_FILTER
1895                 /* check if the packet passes the pass and active filters */
1896                 /* the filter instructions are constructed assuming
1897                    a four-byte PPP header on each packet */
1898                 if (ppp->pass_filter || ppp->active_filter) {
1899                         if (skb_unclone(skb, GFP_ATOMIC))
1900                                 goto err;
1901 
1902                         *skb_push(skb, 2) = 0;
1903                         if (ppp->pass_filter &&
1904                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1905                                 if (ppp->debug & 1)
1906                                         netdev_printk(KERN_DEBUG, ppp->dev,
1907                                                       "PPP: inbound frame "
1908                                                       "not passed\n");
1909                                 kfree_skb(skb);
1910                                 return;
1911                         }
1912                         if (!(ppp->active_filter &&
1913                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1914                                 ppp->last_recv = jiffies;
1915                         __skb_pull(skb, 2);
1916                 } else
1917 #endif /* CONFIG_PPP_FILTER */
1918                         ppp->last_recv = jiffies;
1919 
1920                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1921                     ppp->npmode[npi] != NPMODE_PASS) {
1922                         kfree_skb(skb);
1923                 } else {
1924                         /* chop off protocol */
1925                         skb_pull_rcsum(skb, 2);
1926                         skb->dev = ppp->dev;
1927                         skb->protocol = htons(npindex_to_ethertype[npi]);
1928                         skb_reset_mac_header(skb);
1929                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
1930                                                       dev_net(ppp->dev)));
1931                         netif_rx(skb);
1932                 }
1933         }
1934         return;
1935 
1936  err:
1937         kfree_skb(skb);
1938         ppp_receive_error(ppp);
1939 }
1940 
1941 static struct sk_buff *
1942 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1943 {
1944         int proto = PPP_PROTO(skb);
1945         struct sk_buff *ns;
1946         int len;
1947 
1948         /* Until we fix all the decompressor's need to make sure
1949          * data portion is linear.
1950          */
1951         if (!pskb_may_pull(skb, skb->len))
1952                 goto err;
1953 
1954         if (proto == PPP_COMP) {
1955                 int obuff_size;
1956 
1957                 switch(ppp->rcomp->compress_proto) {
1958                 case CI_MPPE:
1959                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1960                         break;
1961                 default:
1962                         obuff_size = ppp->mru + PPP_HDRLEN;
1963                         break;
1964                 }
1965 
1966                 ns = dev_alloc_skb(obuff_size);
1967                 if (!ns) {
1968                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1969                                    "no memory\n");
1970                         goto err;
1971                 }
1972                 /* the decompressor still expects the A/C bytes in the hdr */
1973                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1974                                 skb->len + 2, ns->data, obuff_size);
1975                 if (len < 0) {
1976                         /* Pass the compressed frame to pppd as an
1977                            error indication. */
1978                         if (len == DECOMP_FATALERROR)
1979                                 ppp->rstate |= SC_DC_FERROR;
1980                         kfree_skb(ns);
1981                         goto err;
1982                 }
1983 
1984                 consume_skb(skb);
1985                 skb = ns;
1986                 skb_put(skb, len);
1987                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1988 
1989         } else {
1990                 /* Uncompressed frame - pass to decompressor so it
1991                    can update its dictionary if necessary. */
1992                 if (ppp->rcomp->incomp)
1993                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1994                                            skb->len + 2);
1995         }
1996 
1997         return skb;
1998 
1999  err:
2000         ppp->rstate |= SC_DC_ERROR;
2001         ppp_receive_error(ppp);
2002         return skb;
2003 }
2004 
2005 #ifdef CONFIG_PPP_MULTILINK
2006 /*
2007  * Receive a multilink frame.
2008  * We put it on the reconstruction queue and then pull off
2009  * as many completed frames as we can.
2010  */
2011 static void
2012 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2013 {
2014         u32 mask, seq;
2015         struct channel *ch;
2016         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2017 
2018         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2019                 goto err;               /* no good, throw it away */
2020 
2021         /* Decode sequence number and begin/end bits */
2022         if (ppp->flags & SC_MP_SHORTSEQ) {
2023                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2024                 mask = 0xfff;
2025         } else {
2026                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2027                 mask = 0xffffff;
2028         }
2029         PPP_MP_CB(skb)->BEbits = skb->data[2];
2030         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2031 
2032         /*
2033          * Do protocol ID decompression on the first fragment of each packet.
2034          */
2035         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2036                 *skb_push(skb, 1) = 0;
2037 
2038         /*
2039          * Expand sequence number to 32 bits, making it as close
2040          * as possible to ppp->minseq.
2041          */
2042         seq |= ppp->minseq & ~mask;
2043         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2044                 seq += mask + 1;
2045         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2046                 seq -= mask + 1;        /* should never happen */
2047         PPP_MP_CB(skb)->sequence = seq;
2048         pch->lastseq = seq;
2049 
2050         /*
2051          * If this packet comes before the next one we were expecting,
2052          * drop it.
2053          */
2054         if (seq_before(seq, ppp->nextseq)) {
2055                 kfree_skb(skb);
2056                 ++ppp->dev->stats.rx_dropped;
2057                 ppp_receive_error(ppp);
2058                 return;
2059         }
2060 
2061         /*
2062          * Reevaluate minseq, the minimum over all channels of the
2063          * last sequence number received on each channel.  Because of
2064          * the increasing sequence number rule, we know that any fragment
2065          * before `minseq' which hasn't arrived is never going to arrive.
2066          * The list of channels can't change because we have the receive
2067          * side of the ppp unit locked.
2068          */
2069         list_for_each_entry(ch, &ppp->channels, clist) {
2070                 if (seq_before(ch->lastseq, seq))
2071                         seq = ch->lastseq;
2072         }
2073         if (seq_before(ppp->minseq, seq))
2074                 ppp->minseq = seq;
2075 
2076         /* Put the fragment on the reconstruction queue */
2077         ppp_mp_insert(ppp, skb);
2078 
2079         /* If the queue is getting long, don't wait any longer for packets
2080            before the start of the queue. */
2081         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2082                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2083                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2084                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2085         }
2086 
2087         /* Pull completed packets off the queue and receive them. */
2088         while ((skb = ppp_mp_reconstruct(ppp))) {
2089                 if (pskb_may_pull(skb, 2))
2090                         ppp_receive_nonmp_frame(ppp, skb);
2091                 else {
2092                         ++ppp->dev->stats.rx_length_errors;
2093                         kfree_skb(skb);
2094                         ppp_receive_error(ppp);
2095                 }
2096         }
2097 
2098         return;
2099 
2100  err:
2101         kfree_skb(skb);
2102         ppp_receive_error(ppp);
2103 }
2104 
2105 /*
2106  * Insert a fragment on the MP reconstruction queue.
2107  * The queue is ordered by increasing sequence number.
2108  */
2109 static void
2110 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2111 {
2112         struct sk_buff *p;
2113         struct sk_buff_head *list = &ppp->mrq;
2114         u32 seq = PPP_MP_CB(skb)->sequence;
2115 
2116         /* N.B. we don't need to lock the list lock because we have the
2117            ppp unit receive-side lock. */
2118         skb_queue_walk(list, p) {
2119                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2120                         break;
2121         }
2122         __skb_queue_before(list, p, skb);
2123 }
2124 
2125 /*
2126  * Reconstruct a packet from the MP fragment queue.
2127  * We go through increasing sequence numbers until we find a
2128  * complete packet, or we get to the sequence number for a fragment
2129  * which hasn't arrived but might still do so.
2130  */
2131 static struct sk_buff *
2132 ppp_mp_reconstruct(struct ppp *ppp)
2133 {
2134         u32 seq = ppp->nextseq;
2135         u32 minseq = ppp->minseq;
2136         struct sk_buff_head *list = &ppp->mrq;
2137         struct sk_buff *p, *tmp;
2138         struct sk_buff *head, *tail;
2139         struct sk_buff *skb = NULL;
2140         int lost = 0, len = 0;
2141 
2142         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2143                 return NULL;
2144         head = list->next;
2145         tail = NULL;
2146         skb_queue_walk_safe(list, p, tmp) {
2147         again:
2148                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2149                         /* this can't happen, anyway ignore the skb */
2150                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2151                                    "seq %u < %u\n",
2152                                    PPP_MP_CB(p)->sequence, seq);
2153                         __skb_unlink(p, list);
2154                         kfree_skb(p);
2155                         continue;
2156                 }
2157                 if (PPP_MP_CB(p)->sequence != seq) {
2158                         u32 oldseq;
2159                         /* Fragment `seq' is missing.  If it is after
2160                            minseq, it might arrive later, so stop here. */
2161                         if (seq_after(seq, minseq))
2162                                 break;
2163                         /* Fragment `seq' is lost, keep going. */
2164                         lost = 1;
2165                         oldseq = seq;
2166                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2167                                 minseq + 1: PPP_MP_CB(p)->sequence;
2168 
2169                         if (ppp->debug & 1)
2170                                 netdev_printk(KERN_DEBUG, ppp->dev,
2171                                               "lost frag %u..%u\n",
2172                                               oldseq, seq-1);
2173 
2174                         goto again;
2175                 }
2176 
2177                 /*
2178                  * At this point we know that all the fragments from
2179                  * ppp->nextseq to seq are either present or lost.
2180                  * Also, there are no complete packets in the queue
2181                  * that have no missing fragments and end before this
2182                  * fragment.
2183                  */
2184 
2185                 /* B bit set indicates this fragment starts a packet */
2186                 if (PPP_MP_CB(p)->BEbits & B) {
2187                         head = p;
2188                         lost = 0;
2189                         len = 0;
2190                 }
2191 
2192                 len += p->len;
2193 
2194                 /* Got a complete packet yet? */
2195                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2196                     (PPP_MP_CB(head)->BEbits & B)) {
2197                         if (len > ppp->mrru + 2) {
2198                                 ++ppp->dev->stats.rx_length_errors;
2199                                 netdev_printk(KERN_DEBUG, ppp->dev,
2200                                               "PPP: reconstructed packet"
2201                                               " is too long (%d)\n", len);
2202                         } else {
2203                                 tail = p;
2204                                 break;
2205                         }
2206                         ppp->nextseq = seq + 1;
2207                 }
2208 
2209                 /*
2210                  * If this is the ending fragment of a packet,
2211                  * and we haven't found a complete valid packet yet,
2212                  * we can discard up to and including this fragment.
2213                  */
2214                 if (PPP_MP_CB(p)->BEbits & E) {
2215                         struct sk_buff *tmp2;
2216 
2217                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2218                                 if (ppp->debug & 1)
2219                                         netdev_printk(KERN_DEBUG, ppp->dev,
2220                                                       "discarding frag %u\n",
2221                                                       PPP_MP_CB(p)->sequence);
2222                                 __skb_unlink(p, list);
2223                                 kfree_skb(p);
2224                         }
2225                         head = skb_peek(list);
2226                         if (!head)
2227                                 break;
2228                 }
2229                 ++seq;
2230         }
2231 
2232         /* If we have a complete packet, copy it all into one skb. */
2233         if (tail != NULL) {
2234                 /* If we have discarded any fragments,
2235                    signal a receive error. */
2236                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2237                         skb_queue_walk_safe(list, p, tmp) {
2238                                 if (p == head)
2239                                         break;
2240                                 if (ppp->debug & 1)
2241                                         netdev_printk(KERN_DEBUG, ppp->dev,
2242                                                       "discarding frag %u\n",
2243                                                       PPP_MP_CB(p)->sequence);
2244                                 __skb_unlink(p, list);
2245                                 kfree_skb(p);
2246                         }
2247 
2248                         if (ppp->debug & 1)
2249                                 netdev_printk(KERN_DEBUG, ppp->dev,
2250                                               "  missed pkts %u..%u\n",
2251                                               ppp->nextseq,
2252                                               PPP_MP_CB(head)->sequence-1);
2253                         ++ppp->dev->stats.rx_dropped;
2254                         ppp_receive_error(ppp);
2255                 }
2256 
2257                 skb = head;
2258                 if (head != tail) {
2259                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2260                         p = skb_queue_next(list, head);
2261                         __skb_unlink(skb, list);
2262                         skb_queue_walk_from_safe(list, p, tmp) {
2263                                 __skb_unlink(p, list);
2264                                 *fragpp = p;
2265                                 p->next = NULL;
2266                                 fragpp = &p->next;
2267 
2268                                 skb->len += p->len;
2269                                 skb->data_len += p->len;
2270                                 skb->truesize += p->truesize;
2271 
2272                                 if (p == tail)
2273                                         break;
2274                         }
2275                 } else {
2276                         __skb_unlink(skb, list);
2277                 }
2278 
2279                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2280         }
2281 
2282         return skb;
2283 }
2284 #endif /* CONFIG_PPP_MULTILINK */
2285 
2286 /*
2287  * Channel interface.
2288  */
2289 
2290 /* Create a new, unattached ppp channel. */
2291 int ppp_register_channel(struct ppp_channel *chan)
2292 {
2293         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2294 }
2295 
2296 /* Create a new, unattached ppp channel for specified net. */
2297 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2298 {
2299         struct channel *pch;
2300         struct ppp_net *pn;
2301 
2302         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2303         if (!pch)
2304                 return -ENOMEM;
2305 
2306         pn = ppp_pernet(net);
2307 
2308         pch->ppp = NULL;
2309         pch->chan = chan;
2310         pch->chan_net = get_net(net);
2311         chan->ppp = pch;
2312         init_ppp_file(&pch->file, CHANNEL);
2313         pch->file.hdrlen = chan->hdrlen;
2314 #ifdef CONFIG_PPP_MULTILINK
2315         pch->lastseq = -1;
2316 #endif /* CONFIG_PPP_MULTILINK */
2317         init_rwsem(&pch->chan_sem);
2318         spin_lock_init(&pch->downl);
2319         rwlock_init(&pch->upl);
2320 
2321         spin_lock_bh(&pn->all_channels_lock);
2322         pch->file.index = ++pn->last_channel_index;
2323         list_add(&pch->list, &pn->new_channels);
2324         atomic_inc(&channel_count);
2325         spin_unlock_bh(&pn->all_channels_lock);
2326 
2327         return 0;
2328 }
2329 
2330 /*
2331  * Return the index of a channel.
2332  */
2333 int ppp_channel_index(struct ppp_channel *chan)
2334 {
2335         struct channel *pch = chan->ppp;
2336 
2337         if (pch)
2338                 return pch->file.index;
2339         return -1;
2340 }
2341 
2342 /*
2343  * Return the PPP unit number to which a channel is connected.
2344  */
2345 int ppp_unit_number(struct ppp_channel *chan)
2346 {
2347         struct channel *pch = chan->ppp;
2348         int unit = -1;
2349 
2350         if (pch) {
2351                 read_lock_bh(&pch->upl);
2352                 if (pch->ppp)
2353                         unit = pch->ppp->file.index;
2354                 read_unlock_bh(&pch->upl);
2355         }
2356         return unit;
2357 }
2358 
2359 /*
2360  * Return the PPP device interface name of a channel.
2361  */
2362 char *ppp_dev_name(struct ppp_channel *chan)
2363 {
2364         struct channel *pch = chan->ppp;
2365         char *name = NULL;
2366 
2367         if (pch) {
2368                 read_lock_bh(&pch->upl);
2369                 if (pch->ppp && pch->ppp->dev)
2370                         name = pch->ppp->dev->name;
2371                 read_unlock_bh(&pch->upl);
2372         }
2373         return name;
2374 }
2375 
2376 
2377 /*
2378  * Disconnect a channel from the generic layer.
2379  * This must be called in process context.
2380  */
2381 void
2382 ppp_unregister_channel(struct ppp_channel *chan)
2383 {
2384         struct channel *pch = chan->ppp;
2385         struct ppp_net *pn;
2386 
2387         if (!pch)
2388                 return;         /* should never happen */
2389 
2390         chan->ppp = NULL;
2391 
2392         /*
2393          * This ensures that we have returned from any calls into the
2394          * the channel's start_xmit or ioctl routine before we proceed.
2395          */
2396         down_write(&pch->chan_sem);
2397         spin_lock_bh(&pch->downl);
2398         pch->chan = NULL;
2399         spin_unlock_bh(&pch->downl);
2400         up_write(&pch->chan_sem);
2401         ppp_disconnect_channel(pch);
2402 
2403         pn = ppp_pernet(pch->chan_net);
2404         spin_lock_bh(&pn->all_channels_lock);
2405         list_del(&pch->list);
2406         spin_unlock_bh(&pn->all_channels_lock);
2407         put_net(pch->chan_net);
2408         pch->chan_net = NULL;
2409 
2410         pch->file.dead = 1;
2411         wake_up_interruptible(&pch->file.rwait);
2412         if (atomic_dec_and_test(&pch->file.refcnt))
2413                 ppp_destroy_channel(pch);
2414 }
2415 
2416 /*
2417  * Callback from a channel when it can accept more to transmit.
2418  * This should be called at BH/softirq level, not interrupt level.
2419  */
2420 void
2421 ppp_output_wakeup(struct ppp_channel *chan)
2422 {
2423         struct channel *pch = chan->ppp;
2424 
2425         if (!pch)
2426                 return;
2427         ppp_channel_push(pch);
2428 }
2429 
2430 /*
2431  * Compression control.
2432  */
2433 
2434 /* Process the PPPIOCSCOMPRESS ioctl. */
2435 static int
2436 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2437 {
2438         int err;
2439         struct compressor *cp, *ocomp;
2440         struct ppp_option_data data;
2441         void *state, *ostate;
2442         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2443 
2444         err = -EFAULT;
2445         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2446                 goto out;
2447         if (data.length > CCP_MAX_OPTION_LENGTH)
2448                 goto out;
2449         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2450                 goto out;
2451 
2452         err = -EINVAL;
2453         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2454                 goto out;
2455 
2456         cp = try_then_request_module(
2457                 find_compressor(ccp_option[0]),
2458                 "ppp-compress-%d", ccp_option[0]);
2459         if (!cp)
2460                 goto out;
2461 
2462         err = -ENOBUFS;
2463         if (data.transmit) {
2464                 state = cp->comp_alloc(ccp_option, data.length);
2465                 if (state) {
2466                         ppp_xmit_lock(ppp);
2467                         ppp->xstate &= ~SC_COMP_RUN;
2468                         ocomp = ppp->xcomp;
2469                         ostate = ppp->xc_state;
2470                         ppp->xcomp = cp;
2471                         ppp->xc_state = state;
2472                         ppp_xmit_unlock(ppp);
2473                         if (ostate) {
2474                                 ocomp->comp_free(ostate);
2475                                 module_put(ocomp->owner);
2476                         }
2477                         err = 0;
2478                 } else
2479                         module_put(cp->owner);
2480 
2481         } else {
2482                 state = cp->decomp_alloc(ccp_option, data.length);
2483                 if (state) {
2484                         ppp_recv_lock(ppp);
2485                         ppp->rstate &= ~SC_DECOMP_RUN;
2486                         ocomp = ppp->rcomp;
2487                         ostate = ppp->rc_state;
2488                         ppp->rcomp = cp;
2489                         ppp->rc_state = state;
2490                         ppp_recv_unlock(ppp);
2491                         if (ostate) {
2492                                 ocomp->decomp_free(ostate);
2493                                 module_put(ocomp->owner);
2494                         }
2495                         err = 0;
2496                 } else
2497                         module_put(cp->owner);
2498         }
2499 
2500  out:
2501         return err;
2502 }
2503 
2504 /*
2505  * Look at a CCP packet and update our state accordingly.
2506  * We assume the caller has the xmit or recv path locked.
2507  */
2508 static void
2509 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2510 {
2511         unsigned char *dp;
2512         int len;
2513 
2514         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2515                 return; /* no header */
2516         dp = skb->data + 2;
2517 
2518         switch (CCP_CODE(dp)) {
2519         case CCP_CONFREQ:
2520 
2521                 /* A ConfReq starts negotiation of compression
2522                  * in one direction of transmission,
2523                  * and hence brings it down...but which way?
2524                  *
2525                  * Remember:
2526                  * A ConfReq indicates what the sender would like to receive
2527                  */
2528                 if(inbound)
2529                         /* He is proposing what I should send */
2530                         ppp->xstate &= ~SC_COMP_RUN;
2531                 else
2532                         /* I am proposing to what he should send */
2533                         ppp->rstate &= ~SC_DECOMP_RUN;
2534 
2535                 break;
2536 
2537         case CCP_TERMREQ:
2538         case CCP_TERMACK:
2539                 /*
2540                  * CCP is going down, both directions of transmission
2541                  */
2542                 ppp->rstate &= ~SC_DECOMP_RUN;
2543                 ppp->xstate &= ~SC_COMP_RUN;
2544                 break;
2545 
2546         case CCP_CONFACK:
2547                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2548                         break;
2549                 len = CCP_LENGTH(dp);
2550                 if (!pskb_may_pull(skb, len + 2))
2551                         return;         /* too short */
2552                 dp += CCP_HDRLEN;
2553                 len -= CCP_HDRLEN;
2554                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2555                         break;
2556                 if (inbound) {
2557                         /* we will start receiving compressed packets */
2558                         if (!ppp->rc_state)
2559                                 break;
2560                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2561                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2562                                 ppp->rstate |= SC_DECOMP_RUN;
2563                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2564                         }
2565                 } else {
2566                         /* we will soon start sending compressed packets */
2567                         if (!ppp->xc_state)
2568                                 break;
2569                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2570                                         ppp->file.index, 0, ppp->debug))
2571                                 ppp->xstate |= SC_COMP_RUN;
2572                 }
2573                 break;
2574 
2575         case CCP_RESETACK:
2576                 /* reset the [de]compressor */
2577                 if ((ppp->flags & SC_CCP_UP) == 0)
2578                         break;
2579                 if (inbound) {
2580                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2581                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2582                                 ppp->rstate &= ~SC_DC_ERROR;
2583                         }
2584                 } else {
2585                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2586                                 ppp->xcomp->comp_reset(ppp->xc_state);
2587                 }
2588                 break;
2589         }
2590 }
2591 
2592 /* Free up compression resources. */
2593 static void
2594 ppp_ccp_closed(struct ppp *ppp)
2595 {
2596         void *xstate, *rstate;
2597         struct compressor *xcomp, *rcomp;
2598 
2599         ppp_lock(ppp);
2600         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2601         ppp->xstate = 0;
2602         xcomp = ppp->xcomp;
2603         xstate = ppp->xc_state;
2604         ppp->xc_state = NULL;
2605         ppp->rstate = 0;
2606         rcomp = ppp->rcomp;
2607         rstate = ppp->rc_state;
2608         ppp->rc_state = NULL;
2609         ppp_unlock(ppp);
2610 
2611         if (xstate) {
2612                 xcomp->comp_free(xstate);
2613                 module_put(xcomp->owner);
2614         }
2615         if (rstate) {
2616                 rcomp->decomp_free(rstate);
2617                 module_put(rcomp->owner);
2618         }
2619 }
2620 
2621 /* List of compressors. */
2622 static LIST_HEAD(compressor_list);
2623 static DEFINE_SPINLOCK(compressor_list_lock);
2624 
2625 struct compressor_entry {
2626         struct list_head list;
2627         struct compressor *comp;
2628 };
2629 
2630 static struct compressor_entry *
2631 find_comp_entry(int proto)
2632 {
2633         struct compressor_entry *ce;
2634 
2635         list_for_each_entry(ce, &compressor_list, list) {
2636                 if (ce->comp->compress_proto == proto)
2637                         return ce;
2638         }
2639         return NULL;
2640 }
2641 
2642 /* Register a compressor */
2643 int
2644 ppp_register_compressor(struct compressor *cp)
2645 {
2646         struct compressor_entry *ce;
2647         int ret;
2648         spin_lock(&compressor_list_lock);
2649         ret = -EEXIST;
2650         if (find_comp_entry(cp->compress_proto))
2651                 goto out;
2652         ret = -ENOMEM;
2653         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2654         if (!ce)
2655                 goto out;
2656         ret = 0;
2657         ce->comp = cp;
2658         list_add(&ce->list, &compressor_list);
2659  out:
2660         spin_unlock(&compressor_list_lock);
2661         return ret;
2662 }
2663 
2664 /* Unregister a compressor */
2665 void
2666 ppp_unregister_compressor(struct compressor *cp)
2667 {
2668         struct compressor_entry *ce;
2669 
2670         spin_lock(&compressor_list_lock);
2671         ce = find_comp_entry(cp->compress_proto);
2672         if (ce && ce->comp == cp) {
2673                 list_del(&ce->list);
2674                 kfree(ce);
2675         }
2676         spin_unlock(&compressor_list_lock);
2677 }
2678 
2679 /* Find a compressor. */
2680 static struct compressor *
2681 find_compressor(int type)
2682 {
2683         struct compressor_entry *ce;
2684         struct compressor *cp = NULL;
2685 
2686         spin_lock(&compressor_list_lock);
2687         ce = find_comp_entry(type);
2688         if (ce) {
2689                 cp = ce->comp;
2690                 if (!try_module_get(cp->owner))
2691                         cp = NULL;
2692         }
2693         spin_unlock(&compressor_list_lock);
2694         return cp;
2695 }
2696 
2697 /*
2698  * Miscelleneous stuff.
2699  */
2700 
2701 static void
2702 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2703 {
2704         struct slcompress *vj = ppp->vj;
2705 
2706         memset(st, 0, sizeof(*st));
2707         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2708         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2709         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2710         st->p.ppp_opackets = ppp->stats64.tx_packets;
2711         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2712         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2713         if (!vj)
2714                 return;
2715         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2716         st->vj.vjs_compressed = vj->sls_o_compressed;
2717         st->vj.vjs_searches = vj->sls_o_searches;
2718         st->vj.vjs_misses = vj->sls_o_misses;
2719         st->vj.vjs_errorin = vj->sls_i_error;
2720         st->vj.vjs_tossed = vj->sls_i_tossed;
2721         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2722         st->vj.vjs_compressedin = vj->sls_i_compressed;
2723 }
2724 
2725 /*
2726  * Stuff for handling the lists of ppp units and channels
2727  * and for initialization.
2728  */
2729 
2730 /*
2731  * Create a new ppp interface unit.  Fails if it can't allocate memory
2732  * or if there is already a unit with the requested number.
2733  * unit == -1 means allocate a new number.
2734  */
2735 static struct ppp *ppp_create_interface(struct net *net, int unit,
2736                                         struct file *file, int *retp)
2737 {
2738         struct ppp *ppp;
2739         struct ppp_net *pn;
2740         struct net_device *dev = NULL;
2741         int ret = -ENOMEM;
2742         int i;
2743 
2744         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
2745         if (!dev)
2746                 goto out1;
2747 
2748         pn = ppp_pernet(net);
2749 
2750         ppp = netdev_priv(dev);
2751         ppp->dev = dev;
2752         ppp->mru = PPP_MRU;
2753         init_ppp_file(&ppp->file, INTERFACE);
2754         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2755         ppp->owner = file;
2756         for (i = 0; i < NUM_NP; ++i)
2757                 ppp->npmode[i] = NPMODE_PASS;
2758         INIT_LIST_HEAD(&ppp->channels);
2759         spin_lock_init(&ppp->rlock);
2760         spin_lock_init(&ppp->wlock);
2761 #ifdef CONFIG_PPP_MULTILINK
2762         ppp->minseq = -1;
2763         skb_queue_head_init(&ppp->mrq);
2764 #endif /* CONFIG_PPP_MULTILINK */
2765 #ifdef CONFIG_PPP_FILTER
2766         ppp->pass_filter = NULL;
2767         ppp->active_filter = NULL;
2768 #endif /* CONFIG_PPP_FILTER */
2769 
2770         /*
2771          * drum roll: don't forget to set
2772          * the net device is belong to
2773          */
2774         dev_net_set(dev, net);
2775 
2776         rtnl_lock();
2777         mutex_lock(&pn->all_ppp_mutex);
2778 
2779         if (unit < 0) {
2780                 unit = unit_get(&pn->units_idr, ppp);
2781                 if (unit < 0) {
2782                         ret = unit;
2783                         goto out2;
2784                 }
2785         } else {
2786                 ret = -EEXIST;
2787                 if (unit_find(&pn->units_idr, unit))
2788                         goto out2; /* unit already exists */
2789                 /*
2790                  * if caller need a specified unit number
2791                  * lets try to satisfy him, otherwise --
2792                  * he should better ask us for new unit number
2793                  *
2794                  * NOTE: yes I know that returning EEXIST it's not
2795                  * fair but at least pppd will ask us to allocate
2796                  * new unit in this case so user is happy :)
2797                  */
2798                 unit = unit_set(&pn->units_idr, ppp, unit);
2799                 if (unit < 0)
2800                         goto out2;
2801         }
2802 
2803         /* Initialize the new ppp unit */
2804         ppp->file.index = unit;
2805         sprintf(dev->name, "ppp%d", unit);
2806 
2807         ret = register_netdevice(dev);
2808         if (ret != 0) {
2809                 unit_put(&pn->units_idr, unit);
2810                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2811                            dev->name, ret);
2812                 goto out2;
2813         }
2814 
2815         ppp->ppp_net = net;
2816 
2817         atomic_inc(&ppp_unit_count);
2818         mutex_unlock(&pn->all_ppp_mutex);
2819         rtnl_unlock();
2820 
2821         *retp = 0;
2822         return ppp;
2823 
2824 out2:
2825         mutex_unlock(&pn->all_ppp_mutex);
2826         rtnl_unlock();
2827         free_netdev(dev);
2828 out1:
2829         *retp = ret;
2830         return NULL;
2831 }
2832 
2833 /*
2834  * Initialize a ppp_file structure.
2835  */
2836 static void
2837 init_ppp_file(struct ppp_file *pf, int kind)
2838 {
2839         pf->kind = kind;
2840         skb_queue_head_init(&pf->xq);
2841         skb_queue_head_init(&pf->rq);
2842         atomic_set(&pf->refcnt, 1);
2843         init_waitqueue_head(&pf->rwait);
2844 }
2845 
2846 /*
2847  * Free the memory used by a ppp unit.  This is only called once
2848  * there are no channels connected to the unit and no file structs
2849  * that reference the unit.
2850  */
2851 static void ppp_destroy_interface(struct ppp *ppp)
2852 {
2853         atomic_dec(&ppp_unit_count);
2854 
2855         if (!ppp->file.dead || ppp->n_channels) {
2856                 /* "can't happen" */
2857                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2858                            "but dead=%d n_channels=%d !\n",
2859                            ppp, ppp->file.dead, ppp->n_channels);
2860                 return;
2861         }
2862 
2863         ppp_ccp_closed(ppp);
2864         if (ppp->vj) {
2865                 slhc_free(ppp->vj);
2866                 ppp->vj = NULL;
2867         }
2868         skb_queue_purge(&ppp->file.xq);
2869         skb_queue_purge(&ppp->file.rq);
2870 #ifdef CONFIG_PPP_MULTILINK
2871         skb_queue_purge(&ppp->mrq);
2872 #endif /* CONFIG_PPP_MULTILINK */
2873 #ifdef CONFIG_PPP_FILTER
2874         if (ppp->pass_filter) {
2875                 bpf_prog_destroy(ppp->pass_filter);
2876                 ppp->pass_filter = NULL;
2877         }
2878 
2879         if (ppp->active_filter) {
2880                 bpf_prog_destroy(ppp->active_filter);
2881                 ppp->active_filter = NULL;
2882         }
2883 #endif /* CONFIG_PPP_FILTER */
2884 
2885         kfree_skb(ppp->xmit_pending);
2886 
2887         free_netdev(ppp->dev);
2888 }
2889 
2890 /*
2891  * Locate an existing ppp unit.
2892  * The caller should have locked the all_ppp_mutex.
2893  */
2894 static struct ppp *
2895 ppp_find_unit(struct ppp_net *pn, int unit)
2896 {
2897         return unit_find(&pn->units_idr, unit);
2898 }
2899 
2900 /*
2901  * Locate an existing ppp channel.
2902  * The caller should have locked the all_channels_lock.
2903  * First we look in the new_channels list, then in the
2904  * all_channels list.  If found in the new_channels list,
2905  * we move it to the all_channels list.  This is for speed
2906  * when we have a lot of channels in use.
2907  */
2908 static struct channel *
2909 ppp_find_channel(struct ppp_net *pn, int unit)
2910 {
2911         struct channel *pch;
2912 
2913         list_for_each_entry(pch, &pn->new_channels, list) {
2914                 if (pch->file.index == unit) {
2915                         list_move(&pch->list, &pn->all_channels);
2916                         return pch;
2917                 }
2918         }
2919 
2920         list_for_each_entry(pch, &pn->all_channels, list) {
2921                 if (pch->file.index == unit)
2922                         return pch;
2923         }
2924 
2925         return NULL;
2926 }
2927 
2928 /*
2929  * Connect a PPP channel to a PPP interface unit.
2930  */
2931 static int
2932 ppp_connect_channel(struct channel *pch, int unit)
2933 {
2934         struct ppp *ppp;
2935         struct ppp_net *pn;
2936         int ret = -ENXIO;
2937         int hdrlen;
2938 
2939         pn = ppp_pernet(pch->chan_net);
2940 
2941         mutex_lock(&pn->all_ppp_mutex);
2942         ppp = ppp_find_unit(pn, unit);
2943         if (!ppp)
2944                 goto out;
2945         write_lock_bh(&pch->upl);
2946         ret = -EINVAL;
2947         if (pch->ppp)
2948                 goto outl;
2949 
2950         ppp_lock(ppp);
2951         if (pch->file.hdrlen > ppp->file.hdrlen)
2952                 ppp->file.hdrlen = pch->file.hdrlen;
2953         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2954         if (hdrlen > ppp->dev->hard_header_len)
2955                 ppp->dev->hard_header_len = hdrlen;
2956         list_add_tail(&pch->clist, &ppp->channels);
2957         ++ppp->n_channels;
2958         pch->ppp = ppp;
2959         atomic_inc(&ppp->file.refcnt);
2960         ppp_unlock(ppp);
2961         ret = 0;
2962 
2963  outl:
2964         write_unlock_bh(&pch->upl);
2965  out:
2966         mutex_unlock(&pn->all_ppp_mutex);
2967         return ret;
2968 }
2969 
2970 /*
2971  * Disconnect a channel from its ppp unit.
2972  */
2973 static int
2974 ppp_disconnect_channel(struct channel *pch)
2975 {
2976         struct ppp *ppp;
2977         int err = -EINVAL;
2978 
2979         write_lock_bh(&pch->upl);
2980         ppp = pch->ppp;
2981         pch->ppp = NULL;
2982         write_unlock_bh(&pch->upl);
2983         if (ppp) {
2984                 /* remove it from the ppp unit's list */
2985                 ppp_lock(ppp);
2986                 list_del(&pch->clist);
2987                 if (--ppp->n_channels == 0)
2988                         wake_up_interruptible(&ppp->file.rwait);
2989                 ppp_unlock(ppp);
2990                 if (atomic_dec_and_test(&ppp->file.refcnt))
2991                         ppp_destroy_interface(ppp);
2992                 err = 0;
2993         }
2994         return err;
2995 }
2996 
2997 /*
2998  * Free up the resources used by a ppp channel.
2999  */
3000 static void ppp_destroy_channel(struct channel *pch)
3001 {
3002         atomic_dec(&channel_count);
3003 
3004         if (!pch->file.dead) {
3005                 /* "can't happen" */
3006                 pr_err("ppp: destroying undead channel %p !\n", pch);
3007                 return;
3008         }
3009         skb_queue_purge(&pch->file.xq);
3010         skb_queue_purge(&pch->file.rq);
3011         kfree(pch);
3012 }
3013 
3014 static void __exit ppp_cleanup(void)
3015 {
3016         /* should never happen */
3017         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3018                 pr_err("PPP: removing module but units remain!\n");
3019         unregister_chrdev(PPP_MAJOR, "ppp");
3020         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3021         class_destroy(ppp_class);
3022         unregister_pernet_device(&ppp_net_ops);
3023 }
3024 
3025 /*
3026  * Units handling. Caller must protect concurrent access
3027  * by holding all_ppp_mutex
3028  */
3029 
3030 /* associate pointer with specified number */
3031 static int unit_set(struct idr *p, void *ptr, int n)
3032 {
3033         int unit;
3034 
3035         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3036         if (unit == -ENOSPC)
3037                 unit = -EINVAL;
3038         return unit;
3039 }
3040 
3041 /* get new free unit number and associate pointer with it */
3042 static int unit_get(struct idr *p, void *ptr)
3043 {
3044         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3045 }
3046 
3047 /* put unit number back to a pool */
3048 static void unit_put(struct idr *p, int n)
3049 {
3050         idr_remove(p, n);
3051 }
3052 
3053 /* get pointer associated with the number */
3054 static void *unit_find(struct idr *p, int n)
3055 {
3056         return idr_find(p, n);
3057 }
3058 
3059 /* Module/initialization stuff */
3060 
3061 module_init(ppp_init);
3062 module_exit(ppp_cleanup);
3063 
3064 EXPORT_SYMBOL(ppp_register_net_channel);
3065 EXPORT_SYMBOL(ppp_register_channel);
3066 EXPORT_SYMBOL(ppp_unregister_channel);
3067 EXPORT_SYMBOL(ppp_channel_index);
3068 EXPORT_SYMBOL(ppp_unit_number);
3069 EXPORT_SYMBOL(ppp_dev_name);
3070 EXPORT_SYMBOL(ppp_input);
3071 EXPORT_SYMBOL(ppp_input_error);
3072 EXPORT_SYMBOL(ppp_output_wakeup);
3073 EXPORT_SYMBOL(ppp_register_compressor);
3074 EXPORT_SYMBOL(ppp_unregister_compressor);
3075 MODULE_LICENSE("GPL");
3076 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3077 MODULE_ALIAS("devname:ppp");
3078 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us