Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

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

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