Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/drivers/net/ppp/ppp_generic.c

  1 /*
  2  * Generic PPP layer for Linux.
  3  *
  4  * Copyright 1999-2002 Paul Mackerras.
  5  *
  6  *  This program is free software; you can redistribute it and/or
  7  *  modify it under the terms of the GNU General Public License
  8  *  as published by the Free Software Foundation; either version
  9  *  2 of the License, or (at your option) any later version.
 10  *
 11  * The generic PPP layer handles the PPP network interfaces, the
 12  * /dev/ppp device, packet and VJ compression, and multilink.
 13  * It talks to PPP `channels' via the interface defined in
 14  * include/linux/ppp_channel.h.  Channels provide the basic means for
 15  * sending and receiving PPP frames on some kind of communications
 16  * channel.
 17  *
 18  * Part of the code in this driver was inspired by the old async-only
 19  * PPP driver, written by Michael Callahan and Al Longyear, and
 20  * subsequently hacked by Paul Mackerras.
 21  *
 22  * ==FILEVERSION 20041108==
 23  */
 24 
 25 #include <linux/module.h>
 26 #include <linux/kernel.h>
 27 #include <linux/kmod.h>
 28 #include <linux/init.h>
 29 #include <linux/list.h>
 30 #include <linux/idr.h>
 31 #include <linux/netdevice.h>
 32 #include <linux/poll.h>
 33 #include <linux/ppp_defs.h>
 34 #include <linux/filter.h>
 35 #include <linux/ppp-ioctl.h>
 36 #include <linux/ppp_channel.h>
 37 #include <linux/ppp-comp.h>
 38 #include <linux/skbuff.h>
 39 #include <linux/rtnetlink.h>
 40 #include <linux/if_arp.h>
 41 #include <linux/ip.h>
 42 #include <linux/tcp.h>
 43 #include <linux/spinlock.h>
 44 #include <linux/rwsem.h>
 45 #include <linux/stddef.h>
 46 #include <linux/device.h>
 47 #include <linux/mutex.h>
 48 #include <linux/slab.h>
 49 #include <linux/file.h>
 50 #include <asm/unaligned.h>
 51 #include <net/slhc_vj.h>
 52 #include <linux/atomic.h>
 53 
 54 #include <linux/nsproxy.h>
 55 #include <net/net_namespace.h>
 56 #include <net/netns/generic.h>
 57 
 58 #define PPP_VERSION     "2.4.2"
 59 
 60 /*
 61  * Network protocols we support.
 62  */
 63 #define NP_IP   0               /* Internet Protocol V4 */
 64 #define NP_IPV6 1               /* Internet Protocol V6 */
 65 #define NP_IPX  2               /* IPX protocol */
 66 #define NP_AT   3               /* Appletalk protocol */
 67 #define NP_MPLS_UC 4            /* MPLS unicast */
 68 #define NP_MPLS_MC 5            /* MPLS multicast */
 69 #define NUM_NP  6               /* Number of NPs. */
 70 
 71 #define MPHDRLEN        6       /* multilink protocol header length */
 72 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
 73 
 74 /*
 75  * An instance of /dev/ppp can be associated with either a ppp
 76  * interface unit or a ppp channel.  In both cases, file->private_data
 77  * points to one of these.
 78  */
 79 struct ppp_file {
 80         enum {
 81                 INTERFACE=1, CHANNEL
 82         }               kind;
 83         struct sk_buff_head xq;         /* pppd transmit queue */
 84         struct sk_buff_head rq;         /* receive queue for pppd */
 85         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
 86         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
 87         int             hdrlen;         /* space to leave for headers */
 88         int             index;          /* interface unit / channel number */
 89         int             dead;           /* unit/channel has been shut down */
 90 };
 91 
 92 #define PF_TO_X(pf, X)          container_of(pf, X, file)
 93 
 94 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
 95 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
 96 
 97 /*
 98  * Data structure to hold primary network stats for which
 99  * we want to use 64 bit storage.  Other network stats
100  * are stored in dev->stats of the ppp strucute.
101  */
102 struct ppp_link_stats {
103         u64 rx_packets;
104         u64 tx_packets;
105         u64 rx_bytes;
106         u64 tx_bytes;
107 };
108 
109 /*
110  * Data structure describing one ppp unit.
111  * A ppp unit corresponds to a ppp network interface device
112  * and represents a multilink bundle.
113  * It can have 0 or more ppp channels connected to it.
114  */
115 struct ppp {
116         struct ppp_file file;           /* stuff for read/write/poll 0 */
117         struct file     *owner;         /* file that owns this unit 48 */
118         struct list_head channels;      /* list of attached channels 4c */
119         int             n_channels;     /* how many channels are attached 54 */
120         spinlock_t      rlock;          /* lock for receive side 58 */
121         spinlock_t      wlock;          /* lock for transmit side 5c */
122         int             mru;            /* max receive unit 60 */
123         unsigned int    flags;          /* control bits 64 */
124         unsigned int    xstate;         /* transmit state bits 68 */
125         unsigned int    rstate;         /* receive state bits 6c */
126         int             debug;          /* debug flags 70 */
127         struct slcompress *vj;          /* state for VJ header compression */
128         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
129         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
130         struct compressor *xcomp;       /* transmit packet compressor 8c */
131         void            *xc_state;      /* its internal state 90 */
132         struct compressor *rcomp;       /* receive decompressor 94 */
133         void            *rc_state;      /* its internal state 98 */
134         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
135         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
136         struct net_device *dev;         /* network interface device a4 */
137         int             closing;        /* is device closing down? a8 */
138 #ifdef CONFIG_PPP_MULTILINK
139         int             nxchan;         /* next channel to send something on */
140         u32             nxseq;          /* next sequence number to send */
141         int             mrru;           /* MP: max reconst. receive unit */
142         u32             nextseq;        /* MP: seq no of next packet */
143         u32             minseq;         /* MP: min of most recent seqnos */
144         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
145 #endif /* CONFIG_PPP_MULTILINK */
146 #ifdef CONFIG_PPP_FILTER
147         struct bpf_prog *pass_filter;   /* filter for packets to pass */
148         struct bpf_prog *active_filter; /* filter for pkts to reset idle */
149 #endif /* CONFIG_PPP_FILTER */
150         struct net      *ppp_net;       /* the net we belong to */
151         struct ppp_link_stats stats64;  /* 64 bit network stats */
152 };
153 
154 /*
155  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
156  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
157  * SC_MUST_COMP
158  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
159  * Bits in xstate: SC_COMP_RUN
160  */
161 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
162                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
163                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
164 
165 /*
166  * Private data structure for each channel.
167  * This includes the data structure used for multilink.
168  */
169 struct channel {
170         struct ppp_file file;           /* stuff for read/write/poll */
171         struct list_head list;          /* link in all/new_channels list */
172         struct ppp_channel *chan;       /* public channel data structure */
173         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
174         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
175         struct ppp      *ppp;           /* ppp unit we're connected to */
176         struct net      *chan_net;      /* the net channel belongs to */
177         struct list_head clist;         /* link in list of channels per unit */
178         rwlock_t        upl;            /* protects `ppp' */
179 #ifdef CONFIG_PPP_MULTILINK
180         u8              avail;          /* flag used in multilink stuff */
181         u8              had_frag;       /* >= 1 fragments have been sent */
182         u32             lastseq;        /* MP: last sequence # received */
183         int             speed;          /* speed of the corresponding ppp channel*/
184 #endif /* CONFIG_PPP_MULTILINK */
185 };
186 
187 struct ppp_config {
188         struct file *file;
189         s32 unit;
190         bool ifname_is_set;
191 };
192 
193 /*
194  * SMP locking issues:
195  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
196  * list and the ppp.n_channels field, you need to take both locks
197  * before you modify them.
198  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
199  * channel.downl.
200  */
201 
202 static DEFINE_MUTEX(ppp_mutex);
203 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
204 static atomic_t channel_count = ATOMIC_INIT(0);
205 
206 /* per-net private data for this module */
207 static unsigned int ppp_net_id __read_mostly;
208 struct ppp_net {
209         /* units to ppp mapping */
210         struct idr units_idr;
211 
212         /*
213          * all_ppp_mutex protects the units_idr mapping.
214          * It also ensures that finding a ppp unit in the units_idr
215          * map and updating its file.refcnt field is atomic.
216          */
217         struct mutex all_ppp_mutex;
218 
219         /* channels */
220         struct list_head all_channels;
221         struct list_head new_channels;
222         int last_channel_index;
223 
224         /*
225          * all_channels_lock protects all_channels and
226          * last_channel_index, and the atomicity of find
227          * a channel and updating its file.refcnt field.
228          */
229         spinlock_t all_channels_lock;
230 };
231 
232 /* Get the PPP protocol number from a skb */
233 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
234 
235 /* We limit the length of ppp->file.rq to this (arbitrary) value */
236 #define PPP_MAX_RQLEN   32
237 
238 /*
239  * Maximum number of multilink fragments queued up.
240  * This has to be large enough to cope with the maximum latency of
241  * the slowest channel relative to the others.  Strictly it should
242  * depend on the number of channels and their characteristics.
243  */
244 #define PPP_MP_MAX_QLEN 128
245 
246 /* Multilink header bits. */
247 #define B       0x80            /* this fragment begins a packet */
248 #define E       0x40            /* this fragment ends a packet */
249 
250 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
251 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
252 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
253 
254 /* Prototypes. */
255 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
256                         struct file *file, unsigned int cmd, unsigned long arg);
257 static void ppp_xmit_process(struct ppp *ppp);
258 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
259 static void ppp_push(struct ppp *ppp);
260 static void ppp_channel_push(struct channel *pch);
261 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
262                               struct channel *pch);
263 static void ppp_receive_error(struct ppp *ppp);
264 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
265 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
266                                             struct sk_buff *skb);
267 #ifdef CONFIG_PPP_MULTILINK
268 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
269                                 struct channel *pch);
270 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
271 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
272 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
273 #endif /* CONFIG_PPP_MULTILINK */
274 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
275 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
276 static void ppp_ccp_closed(struct ppp *ppp);
277 static struct compressor *find_compressor(int type);
278 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
279 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
280 static void init_ppp_file(struct ppp_file *pf, int kind);
281 static void ppp_destroy_interface(struct ppp *ppp);
282 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
283 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
284 static int ppp_connect_channel(struct channel *pch, int unit);
285 static int ppp_disconnect_channel(struct channel *pch);
286 static void ppp_destroy_channel(struct channel *pch);
287 static int unit_get(struct idr *p, void *ptr);
288 static int unit_set(struct idr *p, void *ptr, int n);
289 static void unit_put(struct idr *p, int n);
290 static void *unit_find(struct idr *p, int n);
291 static void ppp_setup(struct net_device *dev);
292 
293 static const struct net_device_ops ppp_netdev_ops;
294 
295 static struct class *ppp_class;
296 
297 /* per net-namespace data */
298 static inline struct ppp_net *ppp_pernet(struct net *net)
299 {
300         BUG_ON(!net);
301 
302         return net_generic(net, ppp_net_id);
303 }
304 
305 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
306 static inline int proto_to_npindex(int proto)
307 {
308         switch (proto) {
309         case PPP_IP:
310                 return NP_IP;
311         case PPP_IPV6:
312                 return NP_IPV6;
313         case PPP_IPX:
314                 return NP_IPX;
315         case PPP_AT:
316                 return NP_AT;
317         case PPP_MPLS_UC:
318                 return NP_MPLS_UC;
319         case PPP_MPLS_MC:
320                 return NP_MPLS_MC;
321         }
322         return -EINVAL;
323 }
324 
325 /* Translates an NP index into a PPP protocol number */
326 static const int npindex_to_proto[NUM_NP] = {
327         PPP_IP,
328         PPP_IPV6,
329         PPP_IPX,
330         PPP_AT,
331         PPP_MPLS_UC,
332         PPP_MPLS_MC,
333 };
334 
335 /* Translates an ethertype into an NP index */
336 static inline int ethertype_to_npindex(int ethertype)
337 {
338         switch (ethertype) {
339         case ETH_P_IP:
340                 return NP_IP;
341         case ETH_P_IPV6:
342                 return NP_IPV6;
343         case ETH_P_IPX:
344                 return NP_IPX;
345         case ETH_P_PPPTALK:
346         case ETH_P_ATALK:
347                 return NP_AT;
348         case ETH_P_MPLS_UC:
349                 return NP_MPLS_UC;
350         case ETH_P_MPLS_MC:
351                 return NP_MPLS_MC;
352         }
353         return -1;
354 }
355 
356 /* Translates an NP index into an ethertype */
357 static const int npindex_to_ethertype[NUM_NP] = {
358         ETH_P_IP,
359         ETH_P_IPV6,
360         ETH_P_IPX,
361         ETH_P_PPPTALK,
362         ETH_P_MPLS_UC,
363         ETH_P_MPLS_MC,
364 };
365 
366 /*
367  * Locking shorthand.
368  */
369 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
370 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
371 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
372 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
373 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
374                                      ppp_recv_lock(ppp); } while (0)
375 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
376                                      ppp_xmit_unlock(ppp); } while (0)
377 
378 /*
379  * /dev/ppp device routines.
380  * The /dev/ppp device is used by pppd to control the ppp unit.
381  * It supports the read, write, ioctl and poll functions.
382  * Open instances of /dev/ppp can be in one of three states:
383  * unattached, attached to a ppp unit, or attached to a ppp channel.
384  */
385 static int ppp_open(struct inode *inode, struct file *file)
386 {
387         /*
388          * This could (should?) be enforced by the permissions on /dev/ppp.
389          */
390         if (!capable(CAP_NET_ADMIN))
391                 return -EPERM;
392         return 0;
393 }
394 
395 static int ppp_release(struct inode *unused, struct file *file)
396 {
397         struct ppp_file *pf = file->private_data;
398         struct ppp *ppp;
399 
400         if (pf) {
401                 file->private_data = NULL;
402                 if (pf->kind == INTERFACE) {
403                         ppp = PF_TO_PPP(pf);
404                         rtnl_lock();
405                         if (file == ppp->owner)
406                                 unregister_netdevice(ppp->dev);
407                         rtnl_unlock();
408                 }
409                 if (atomic_dec_and_test(&pf->refcnt)) {
410                         switch (pf->kind) {
411                         case INTERFACE:
412                                 ppp_destroy_interface(PF_TO_PPP(pf));
413                                 break;
414                         case CHANNEL:
415                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
416                                 break;
417                         }
418                 }
419         }
420         return 0;
421 }
422 
423 static ssize_t ppp_read(struct file *file, char __user *buf,
424                         size_t count, loff_t *ppos)
425 {
426         struct ppp_file *pf = file->private_data;
427         DECLARE_WAITQUEUE(wait, current);
428         ssize_t ret;
429         struct sk_buff *skb = NULL;
430         struct iovec iov;
431         struct iov_iter to;
432 
433         ret = count;
434 
435         if (!pf)
436                 return -ENXIO;
437         add_wait_queue(&pf->rwait, &wait);
438         for (;;) {
439                 set_current_state(TASK_INTERRUPTIBLE);
440                 skb = skb_dequeue(&pf->rq);
441                 if (skb)
442                         break;
443                 ret = 0;
444                 if (pf->dead)
445                         break;
446                 if (pf->kind == INTERFACE) {
447                         /*
448                          * Return 0 (EOF) on an interface that has no
449                          * channels connected, unless it is looping
450                          * network traffic (demand mode).
451                          */
452                         struct ppp *ppp = PF_TO_PPP(pf);
453 
454                         ppp_recv_lock(ppp);
455                         if (ppp->n_channels == 0 &&
456                             (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
457                                 ppp_recv_unlock(ppp);
458                                 break;
459                         }
460                         ppp_recv_unlock(ppp);
461                 }
462                 ret = -EAGAIN;
463                 if (file->f_flags & O_NONBLOCK)
464                         break;
465                 ret = -ERESTARTSYS;
466                 if (signal_pending(current))
467                         break;
468                 schedule();
469         }
470         set_current_state(TASK_RUNNING);
471         remove_wait_queue(&pf->rwait, &wait);
472 
473         if (!skb)
474                 goto out;
475 
476         ret = -EOVERFLOW;
477         if (skb->len > count)
478                 goto outf;
479         ret = -EFAULT;
480         iov.iov_base = buf;
481         iov.iov_len = count;
482         iov_iter_init(&to, READ, &iov, 1, count);
483         if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
484                 goto outf;
485         ret = skb->len;
486 
487  outf:
488         kfree_skb(skb);
489  out:
490         return ret;
491 }
492 
493 static ssize_t ppp_write(struct file *file, const char __user *buf,
494                          size_t count, loff_t *ppos)
495 {
496         struct ppp_file *pf = file->private_data;
497         struct sk_buff *skb;
498         ssize_t ret;
499 
500         if (!pf)
501                 return -ENXIO;
502         ret = -ENOMEM;
503         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
504         if (!skb)
505                 goto out;
506         skb_reserve(skb, pf->hdrlen);
507         ret = -EFAULT;
508         if (copy_from_user(skb_put(skb, count), buf, count)) {
509                 kfree_skb(skb);
510                 goto out;
511         }
512 
513         skb_queue_tail(&pf->xq, skb);
514 
515         switch (pf->kind) {
516         case INTERFACE:
517                 ppp_xmit_process(PF_TO_PPP(pf));
518                 break;
519         case CHANNEL:
520                 ppp_channel_push(PF_TO_CHANNEL(pf));
521                 break;
522         }
523 
524         ret = count;
525 
526  out:
527         return ret;
528 }
529 
530 /* No kernel lock - fine */
531 static unsigned int ppp_poll(struct file *file, poll_table *wait)
532 {
533         struct ppp_file *pf = file->private_data;
534         unsigned int mask;
535 
536         if (!pf)
537                 return 0;
538         poll_wait(file, &pf->rwait, wait);
539         mask = POLLOUT | POLLWRNORM;
540         if (skb_peek(&pf->rq))
541                 mask |= POLLIN | POLLRDNORM;
542         if (pf->dead)
543                 mask |= POLLHUP;
544         else if (pf->kind == INTERFACE) {
545                 /* see comment in ppp_read */
546                 struct ppp *ppp = PF_TO_PPP(pf);
547 
548                 ppp_recv_lock(ppp);
549                 if (ppp->n_channels == 0 &&
550                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
551                         mask |= POLLIN | POLLRDNORM;
552                 ppp_recv_unlock(ppp);
553         }
554 
555         return mask;
556 }
557 
558 #ifdef CONFIG_PPP_FILTER
559 static int get_filter(void __user *arg, struct sock_filter **p)
560 {
561         struct sock_fprog uprog;
562         struct sock_filter *code = NULL;
563         int len;
564 
565         if (copy_from_user(&uprog, arg, sizeof(uprog)))
566                 return -EFAULT;
567 
568         if (!uprog.len) {
569                 *p = NULL;
570                 return 0;
571         }
572 
573         len = uprog.len * sizeof(struct sock_filter);
574         code = memdup_user(uprog.filter, len);
575         if (IS_ERR(code))
576                 return PTR_ERR(code);
577 
578         *p = code;
579         return uprog.len;
580 }
581 #endif /* CONFIG_PPP_FILTER */
582 
583 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
584 {
585         struct ppp_file *pf;
586         struct ppp *ppp;
587         int err = -EFAULT, val, val2, i;
588         struct ppp_idle idle;
589         struct npioctl npi;
590         int unit, cflags;
591         struct slcompress *vj;
592         void __user *argp = (void __user *)arg;
593         int __user *p = argp;
594 
595         mutex_lock(&ppp_mutex);
596 
597         pf = file->private_data;
598         if (!pf) {
599                 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
600                                            pf, file, cmd, arg);
601                 goto out;
602         }
603 
604         if (cmd == PPPIOCDETACH) {
605                 /*
606                  * We have to be careful here... if the file descriptor
607                  * has been dup'd, we could have another process in the
608                  * middle of a poll using the same file *, so we had
609                  * better not free the interface data structures -
610                  * instead we fail the ioctl.  Even in this case, we
611                  * shut down the interface if we are the owner of it.
612                  * Actually, we should get rid of PPPIOCDETACH, userland
613                  * (i.e. pppd) could achieve the same effect by closing
614                  * this fd and reopening /dev/ppp.
615                  */
616                 err = -EINVAL;
617                 if (pf->kind == INTERFACE) {
618                         ppp = PF_TO_PPP(pf);
619                         rtnl_lock();
620                         if (file == ppp->owner)
621                                 unregister_netdevice(ppp->dev);
622                         rtnl_unlock();
623                 }
624                 if (atomic_long_read(&file->f_count) < 2) {
625                         ppp_release(NULL, file);
626                         err = 0;
627                 } else
628                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
629                                 atomic_long_read(&file->f_count));
630                 goto out;
631         }
632 
633         if (pf->kind == CHANNEL) {
634                 struct channel *pch;
635                 struct ppp_channel *chan;
636 
637                 pch = PF_TO_CHANNEL(pf);
638 
639                 switch (cmd) {
640                 case PPPIOCCONNECT:
641                         if (get_user(unit, p))
642                                 break;
643                         err = ppp_connect_channel(pch, unit);
644                         break;
645 
646                 case PPPIOCDISCONN:
647                         err = ppp_disconnect_channel(pch);
648                         break;
649 
650                 default:
651                         down_read(&pch->chan_sem);
652                         chan = pch->chan;
653                         err = -ENOTTY;
654                         if (chan && chan->ops->ioctl)
655                                 err = chan->ops->ioctl(chan, cmd, arg);
656                         up_read(&pch->chan_sem);
657                 }
658                 goto out;
659         }
660 
661         if (pf->kind != INTERFACE) {
662                 /* can't happen */
663                 pr_err("PPP: not interface or channel??\n");
664                 err = -EINVAL;
665                 goto out;
666         }
667 
668         ppp = PF_TO_PPP(pf);
669         switch (cmd) {
670         case PPPIOCSMRU:
671                 if (get_user(val, p))
672                         break;
673                 ppp->mru = val;
674                 err = 0;
675                 break;
676 
677         case PPPIOCSFLAGS:
678                 if (get_user(val, p))
679                         break;
680                 ppp_lock(ppp);
681                 cflags = ppp->flags & ~val;
682 #ifdef CONFIG_PPP_MULTILINK
683                 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
684                         ppp->nextseq = 0;
685 #endif
686                 ppp->flags = val & SC_FLAG_BITS;
687                 ppp_unlock(ppp);
688                 if (cflags & SC_CCP_OPEN)
689                         ppp_ccp_closed(ppp);
690                 err = 0;
691                 break;
692 
693         case PPPIOCGFLAGS:
694                 val = ppp->flags | ppp->xstate | ppp->rstate;
695                 if (put_user(val, p))
696                         break;
697                 err = 0;
698                 break;
699 
700         case PPPIOCSCOMPRESS:
701                 err = ppp_set_compress(ppp, arg);
702                 break;
703 
704         case PPPIOCGUNIT:
705                 if (put_user(ppp->file.index, p))
706                         break;
707                 err = 0;
708                 break;
709 
710         case PPPIOCSDEBUG:
711                 if (get_user(val, p))
712                         break;
713                 ppp->debug = val;
714                 err = 0;
715                 break;
716 
717         case PPPIOCGDEBUG:
718                 if (put_user(ppp->debug, p))
719                         break;
720                 err = 0;
721                 break;
722 
723         case PPPIOCGIDLE:
724                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
725                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
726                 if (copy_to_user(argp, &idle, sizeof(idle)))
727                         break;
728                 err = 0;
729                 break;
730 
731         case PPPIOCSMAXCID:
732                 if (get_user(val, p))
733                         break;
734                 val2 = 15;
735                 if ((val >> 16) != 0) {
736                         val2 = val >> 16;
737                         val &= 0xffff;
738                 }
739                 vj = slhc_init(val2+1, val+1);
740                 if (IS_ERR(vj)) {
741                         err = PTR_ERR(vj);
742                         break;
743                 }
744                 ppp_lock(ppp);
745                 if (ppp->vj)
746                         slhc_free(ppp->vj);
747                 ppp->vj = vj;
748                 ppp_unlock(ppp);
749                 err = 0;
750                 break;
751 
752         case PPPIOCGNPMODE:
753         case PPPIOCSNPMODE:
754                 if (copy_from_user(&npi, argp, sizeof(npi)))
755                         break;
756                 err = proto_to_npindex(npi.protocol);
757                 if (err < 0)
758                         break;
759                 i = err;
760                 if (cmd == PPPIOCGNPMODE) {
761                         err = -EFAULT;
762                         npi.mode = ppp->npmode[i];
763                         if (copy_to_user(argp, &npi, sizeof(npi)))
764                                 break;
765                 } else {
766                         ppp->npmode[i] = npi.mode;
767                         /* we may be able to transmit more packets now (??) */
768                         netif_wake_queue(ppp->dev);
769                 }
770                 err = 0;
771                 break;
772 
773 #ifdef CONFIG_PPP_FILTER
774         case PPPIOCSPASS:
775         {
776                 struct sock_filter *code;
777 
778                 err = get_filter(argp, &code);
779                 if (err >= 0) {
780                         struct bpf_prog *pass_filter = NULL;
781                         struct sock_fprog_kern fprog = {
782                                 .len = err,
783                                 .filter = code,
784                         };
785 
786                         err = 0;
787                         if (fprog.filter)
788                                 err = bpf_prog_create(&pass_filter, &fprog);
789                         if (!err) {
790                                 ppp_lock(ppp);
791                                 if (ppp->pass_filter)
792                                         bpf_prog_destroy(ppp->pass_filter);
793                                 ppp->pass_filter = pass_filter;
794                                 ppp_unlock(ppp);
795                         }
796                         kfree(code);
797                 }
798                 break;
799         }
800         case PPPIOCSACTIVE:
801         {
802                 struct sock_filter *code;
803 
804                 err = get_filter(argp, &code);
805                 if (err >= 0) {
806                         struct bpf_prog *active_filter = NULL;
807                         struct sock_fprog_kern fprog = {
808                                 .len = err,
809                                 .filter = code,
810                         };
811 
812                         err = 0;
813                         if (fprog.filter)
814                                 err = bpf_prog_create(&active_filter, &fprog);
815                         if (!err) {
816                                 ppp_lock(ppp);
817                                 if (ppp->active_filter)
818                                         bpf_prog_destroy(ppp->active_filter);
819                                 ppp->active_filter = active_filter;
820                                 ppp_unlock(ppp);
821                         }
822                         kfree(code);
823                 }
824                 break;
825         }
826 #endif /* CONFIG_PPP_FILTER */
827 
828 #ifdef CONFIG_PPP_MULTILINK
829         case PPPIOCSMRRU:
830                 if (get_user(val, p))
831                         break;
832                 ppp_recv_lock(ppp);
833                 ppp->mrru = val;
834                 ppp_recv_unlock(ppp);
835                 err = 0;
836                 break;
837 #endif /* CONFIG_PPP_MULTILINK */
838 
839         default:
840                 err = -ENOTTY;
841         }
842 
843 out:
844         mutex_unlock(&ppp_mutex);
845 
846         return err;
847 }
848 
849 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
850                         struct file *file, unsigned int cmd, unsigned long arg)
851 {
852         int unit, err = -EFAULT;
853         struct ppp *ppp;
854         struct channel *chan;
855         struct ppp_net *pn;
856         int __user *p = (int __user *)arg;
857 
858         switch (cmd) {
859         case PPPIOCNEWUNIT:
860                 /* Create a new ppp unit */
861                 if (get_user(unit, p))
862                         break;
863                 err = ppp_create_interface(net, file, &unit);
864                 if (err < 0)
865                         break;
866 
867                 err = -EFAULT;
868                 if (put_user(unit, p))
869                         break;
870                 err = 0;
871                 break;
872 
873         case PPPIOCATTACH:
874                 /* Attach to an existing ppp unit */
875                 if (get_user(unit, p))
876                         break;
877                 err = -ENXIO;
878                 pn = ppp_pernet(net);
879                 mutex_lock(&pn->all_ppp_mutex);
880                 ppp = ppp_find_unit(pn, unit);
881                 if (ppp) {
882                         atomic_inc(&ppp->file.refcnt);
883                         file->private_data = &ppp->file;
884                         err = 0;
885                 }
886                 mutex_unlock(&pn->all_ppp_mutex);
887                 break;
888 
889         case PPPIOCATTCHAN:
890                 if (get_user(unit, p))
891                         break;
892                 err = -ENXIO;
893                 pn = ppp_pernet(net);
894                 spin_lock_bh(&pn->all_channels_lock);
895                 chan = ppp_find_channel(pn, unit);
896                 if (chan) {
897                         atomic_inc(&chan->file.refcnt);
898                         file->private_data = &chan->file;
899                         err = 0;
900                 }
901                 spin_unlock_bh(&pn->all_channels_lock);
902                 break;
903 
904         default:
905                 err = -ENOTTY;
906         }
907 
908         return err;
909 }
910 
911 static const struct file_operations ppp_device_fops = {
912         .owner          = THIS_MODULE,
913         .read           = ppp_read,
914         .write          = ppp_write,
915         .poll           = ppp_poll,
916         .unlocked_ioctl = ppp_ioctl,
917         .open           = ppp_open,
918         .release        = ppp_release,
919         .llseek         = noop_llseek,
920 };
921 
922 static __net_init int ppp_init_net(struct net *net)
923 {
924         struct ppp_net *pn = net_generic(net, ppp_net_id);
925 
926         idr_init(&pn->units_idr);
927         mutex_init(&pn->all_ppp_mutex);
928 
929         INIT_LIST_HEAD(&pn->all_channels);
930         INIT_LIST_HEAD(&pn->new_channels);
931 
932         spin_lock_init(&pn->all_channels_lock);
933 
934         return 0;
935 }
936 
937 static __net_exit void ppp_exit_net(struct net *net)
938 {
939         struct ppp_net *pn = net_generic(net, ppp_net_id);
940         struct net_device *dev;
941         struct net_device *aux;
942         struct ppp *ppp;
943         LIST_HEAD(list);
944         int id;
945 
946         rtnl_lock();
947         for_each_netdev_safe(net, dev, aux) {
948                 if (dev->netdev_ops == &ppp_netdev_ops)
949                         unregister_netdevice_queue(dev, &list);
950         }
951 
952         idr_for_each_entry(&pn->units_idr, ppp, id)
953                 /* Skip devices already unregistered by previous loop */
954                 if (!net_eq(dev_net(ppp->dev), net))
955                         unregister_netdevice_queue(ppp->dev, &list);
956 
957         unregister_netdevice_many(&list);
958         rtnl_unlock();
959 
960         idr_destroy(&pn->units_idr);
961 }
962 
963 static struct pernet_operations ppp_net_ops = {
964         .init = ppp_init_net,
965         .exit = ppp_exit_net,
966         .id   = &ppp_net_id,
967         .size = sizeof(struct ppp_net),
968 };
969 
970 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
971 {
972         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
973         int ret;
974 
975         mutex_lock(&pn->all_ppp_mutex);
976 
977         if (unit < 0) {
978                 ret = unit_get(&pn->units_idr, ppp);
979                 if (ret < 0)
980                         goto err;
981         } else {
982                 /* Caller asked for a specific unit number. Fail with -EEXIST
983                  * if unavailable. For backward compatibility, return -EEXIST
984                  * too if idr allocation fails; this makes pppd retry without
985                  * requesting a specific unit number.
986                  */
987                 if (unit_find(&pn->units_idr, unit)) {
988                         ret = -EEXIST;
989                         goto err;
990                 }
991                 ret = unit_set(&pn->units_idr, ppp, unit);
992                 if (ret < 0) {
993                         /* Rewrite error for backward compatibility */
994                         ret = -EEXIST;
995                         goto err;
996                 }
997         }
998         ppp->file.index = ret;
999 
1000         if (!ifname_is_set)
1001                 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1002 
1003         ret = register_netdevice(ppp->dev);
1004         if (ret < 0)
1005                 goto err_unit;
1006 
1007         atomic_inc(&ppp_unit_count);
1008 
1009         mutex_unlock(&pn->all_ppp_mutex);
1010 
1011         return 0;
1012 
1013 err_unit:
1014         unit_put(&pn->units_idr, ppp->file.index);
1015 err:
1016         mutex_unlock(&pn->all_ppp_mutex);
1017 
1018         return ret;
1019 }
1020 
1021 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1022                              const struct ppp_config *conf)
1023 {
1024         struct ppp *ppp = netdev_priv(dev);
1025         int indx;
1026         int err;
1027 
1028         ppp->dev = dev;
1029         ppp->ppp_net = src_net;
1030         ppp->mru = PPP_MRU;
1031         ppp->owner = conf->file;
1032 
1033         init_ppp_file(&ppp->file, INTERFACE);
1034         ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1035 
1036         for (indx = 0; indx < NUM_NP; ++indx)
1037                 ppp->npmode[indx] = NPMODE_PASS;
1038         INIT_LIST_HEAD(&ppp->channels);
1039         spin_lock_init(&ppp->rlock);
1040         spin_lock_init(&ppp->wlock);
1041 #ifdef CONFIG_PPP_MULTILINK
1042         ppp->minseq = -1;
1043         skb_queue_head_init(&ppp->mrq);
1044 #endif /* CONFIG_PPP_MULTILINK */
1045 #ifdef CONFIG_PPP_FILTER
1046         ppp->pass_filter = NULL;
1047         ppp->active_filter = NULL;
1048 #endif /* CONFIG_PPP_FILTER */
1049 
1050         err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1051         if (err < 0)
1052                 return err;
1053 
1054         conf->file->private_data = &ppp->file;
1055 
1056         return 0;
1057 }
1058 
1059 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1060         [IFLA_PPP_DEV_FD]       = { .type = NLA_S32 },
1061 };
1062 
1063 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[])
1064 {
1065         if (!data)
1066                 return -EINVAL;
1067 
1068         if (!data[IFLA_PPP_DEV_FD])
1069                 return -EINVAL;
1070         if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1071                 return -EBADF;
1072 
1073         return 0;
1074 }
1075 
1076 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1077                           struct nlattr *tb[], struct nlattr *data[])
1078 {
1079         struct ppp_config conf = {
1080                 .unit = -1,
1081                 .ifname_is_set = true,
1082         };
1083         struct file *file;
1084         int err;
1085 
1086         file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1087         if (!file)
1088                 return -EBADF;
1089 
1090         /* rtnl_lock is already held here, but ppp_create_interface() locks
1091          * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1092          * possible deadlock due to lock order inversion, at the cost of
1093          * pushing the problem back to userspace.
1094          */
1095         if (!mutex_trylock(&ppp_mutex)) {
1096                 err = -EBUSY;
1097                 goto out;
1098         }
1099 
1100         if (file->f_op != &ppp_device_fops || file->private_data) {
1101                 err = -EBADF;
1102                 goto out_unlock;
1103         }
1104 
1105         conf.file = file;
1106 
1107         /* Don't use device name generated by the rtnetlink layer when ifname
1108          * isn't specified. Let ppp_dev_configure() set the device name using
1109          * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1110          * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1111          */
1112         if (!tb[IFLA_IFNAME])
1113                 conf.ifname_is_set = false;
1114 
1115         err = ppp_dev_configure(src_net, dev, &conf);
1116 
1117 out_unlock:
1118         mutex_unlock(&ppp_mutex);
1119 out:
1120         fput(file);
1121 
1122         return err;
1123 }
1124 
1125 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1126 {
1127         unregister_netdevice_queue(dev, head);
1128 }
1129 
1130 static size_t ppp_nl_get_size(const struct net_device *dev)
1131 {
1132         return 0;
1133 }
1134 
1135 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1136 {
1137         return 0;
1138 }
1139 
1140 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1141 {
1142         struct ppp *ppp = netdev_priv(dev);
1143 
1144         return ppp->ppp_net;
1145 }
1146 
1147 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1148         .kind           = "ppp",
1149         .maxtype        = IFLA_PPP_MAX,
1150         .policy         = ppp_nl_policy,
1151         .priv_size      = sizeof(struct ppp),
1152         .setup          = ppp_setup,
1153         .validate       = ppp_nl_validate,
1154         .newlink        = ppp_nl_newlink,
1155         .dellink        = ppp_nl_dellink,
1156         .get_size       = ppp_nl_get_size,
1157         .fill_info      = ppp_nl_fill_info,
1158         .get_link_net   = ppp_nl_get_link_net,
1159 };
1160 
1161 #define PPP_MAJOR       108
1162 
1163 /* Called at boot time if ppp is compiled into the kernel,
1164    or at module load time (from init_module) if compiled as a module. */
1165 static int __init ppp_init(void)
1166 {
1167         int err;
1168 
1169         pr_info("PPP generic driver version " PPP_VERSION "\n");
1170 
1171         err = register_pernet_device(&ppp_net_ops);
1172         if (err) {
1173                 pr_err("failed to register PPP pernet device (%d)\n", err);
1174                 goto out;
1175         }
1176 
1177         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1178         if (err) {
1179                 pr_err("failed to register PPP device (%d)\n", err);
1180                 goto out_net;
1181         }
1182 
1183         ppp_class = class_create(THIS_MODULE, "ppp");
1184         if (IS_ERR(ppp_class)) {
1185                 err = PTR_ERR(ppp_class);
1186                 goto out_chrdev;
1187         }
1188 
1189         err = rtnl_link_register(&ppp_link_ops);
1190         if (err) {
1191                 pr_err("failed to register rtnetlink PPP handler\n");
1192                 goto out_class;
1193         }
1194 
1195         /* not a big deal if we fail here :-) */
1196         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1197 
1198         return 0;
1199 
1200 out_class:
1201         class_destroy(ppp_class);
1202 out_chrdev:
1203         unregister_chrdev(PPP_MAJOR, "ppp");
1204 out_net:
1205         unregister_pernet_device(&ppp_net_ops);
1206 out:
1207         return err;
1208 }
1209 
1210 /*
1211  * Network interface unit routines.
1212  */
1213 static netdev_tx_t
1214 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1215 {
1216         struct ppp *ppp = netdev_priv(dev);
1217         int npi, proto;
1218         unsigned char *pp;
1219 
1220         npi = ethertype_to_npindex(ntohs(skb->protocol));
1221         if (npi < 0)
1222                 goto outf;
1223 
1224         /* Drop, accept or reject the packet */
1225         switch (ppp->npmode[npi]) {
1226         case NPMODE_PASS:
1227                 break;
1228         case NPMODE_QUEUE:
1229                 /* it would be nice to have a way to tell the network
1230                    system to queue this one up for later. */
1231                 goto outf;
1232         case NPMODE_DROP:
1233         case NPMODE_ERROR:
1234                 goto outf;
1235         }
1236 
1237         /* Put the 2-byte PPP protocol number on the front,
1238            making sure there is room for the address and control fields. */
1239         if (skb_cow_head(skb, PPP_HDRLEN))
1240                 goto outf;
1241 
1242         pp = skb_push(skb, 2);
1243         proto = npindex_to_proto[npi];
1244         put_unaligned_be16(proto, pp);
1245 
1246         skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1247         skb_queue_tail(&ppp->file.xq, skb);
1248         ppp_xmit_process(ppp);
1249         return NETDEV_TX_OK;
1250 
1251  outf:
1252         kfree_skb(skb);
1253         ++dev->stats.tx_dropped;
1254         return NETDEV_TX_OK;
1255 }
1256 
1257 static int
1258 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1259 {
1260         struct ppp *ppp = netdev_priv(dev);
1261         int err = -EFAULT;
1262         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1263         struct ppp_stats stats;
1264         struct ppp_comp_stats cstats;
1265         char *vers;
1266 
1267         switch (cmd) {
1268         case SIOCGPPPSTATS:
1269                 ppp_get_stats(ppp, &stats);
1270                 if (copy_to_user(addr, &stats, sizeof(stats)))
1271                         break;
1272                 err = 0;
1273                 break;
1274 
1275         case SIOCGPPPCSTATS:
1276                 memset(&cstats, 0, sizeof(cstats));
1277                 if (ppp->xc_state)
1278                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1279                 if (ppp->rc_state)
1280                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1281                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1282                         break;
1283                 err = 0;
1284                 break;
1285 
1286         case SIOCGPPPVER:
1287                 vers = PPP_VERSION;
1288                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1289                         break;
1290                 err = 0;
1291                 break;
1292 
1293         default:
1294                 err = -EINVAL;
1295         }
1296 
1297         return err;
1298 }
1299 
1300 static struct rtnl_link_stats64*
1301 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1302 {
1303         struct ppp *ppp = netdev_priv(dev);
1304 
1305         ppp_recv_lock(ppp);
1306         stats64->rx_packets = ppp->stats64.rx_packets;
1307         stats64->rx_bytes   = ppp->stats64.rx_bytes;
1308         ppp_recv_unlock(ppp);
1309 
1310         ppp_xmit_lock(ppp);
1311         stats64->tx_packets = ppp->stats64.tx_packets;
1312         stats64->tx_bytes   = ppp->stats64.tx_bytes;
1313         ppp_xmit_unlock(ppp);
1314 
1315         stats64->rx_errors        = dev->stats.rx_errors;
1316         stats64->tx_errors        = dev->stats.tx_errors;
1317         stats64->rx_dropped       = dev->stats.rx_dropped;
1318         stats64->tx_dropped       = dev->stats.tx_dropped;
1319         stats64->rx_length_errors = dev->stats.rx_length_errors;
1320 
1321         return stats64;
1322 }
1323 
1324 static int ppp_dev_init(struct net_device *dev)
1325 {
1326         netdev_lockdep_set_classes(dev);
1327         return 0;
1328 }
1329 
1330 static void ppp_dev_uninit(struct net_device *dev)
1331 {
1332         struct ppp *ppp = netdev_priv(dev);
1333         struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1334 
1335         ppp_lock(ppp);
1336         ppp->closing = 1;
1337         ppp_unlock(ppp);
1338 
1339         mutex_lock(&pn->all_ppp_mutex);
1340         unit_put(&pn->units_idr, ppp->file.index);
1341         mutex_unlock(&pn->all_ppp_mutex);
1342 
1343         ppp->owner = NULL;
1344 
1345         ppp->file.dead = 1;
1346         wake_up_interruptible(&ppp->file.rwait);
1347 }
1348 
1349 static const struct net_device_ops ppp_netdev_ops = {
1350         .ndo_init        = ppp_dev_init,
1351         .ndo_uninit      = ppp_dev_uninit,
1352         .ndo_start_xmit  = ppp_start_xmit,
1353         .ndo_do_ioctl    = ppp_net_ioctl,
1354         .ndo_get_stats64 = ppp_get_stats64,
1355 };
1356 
1357 static struct device_type ppp_type = {
1358         .name = "ppp",
1359 };
1360 
1361 static void ppp_setup(struct net_device *dev)
1362 {
1363         dev->netdev_ops = &ppp_netdev_ops;
1364         SET_NETDEV_DEVTYPE(dev, &ppp_type);
1365 
1366         dev->features |= NETIF_F_LLTX;
1367 
1368         dev->hard_header_len = PPP_HDRLEN;
1369         dev->mtu = PPP_MRU;
1370         dev->addr_len = 0;
1371         dev->tx_queue_len = 3;
1372         dev->type = ARPHRD_PPP;
1373         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1374         netif_keep_dst(dev);
1375 }
1376 
1377 /*
1378  * Transmit-side routines.
1379  */
1380 
1381 /* Called to do any work queued up on the transmit side that can now be done */
1382 static void __ppp_xmit_process(struct ppp *ppp)
1383 {
1384         struct sk_buff *skb;
1385 
1386         ppp_xmit_lock(ppp);
1387         if (!ppp->closing) {
1388                 ppp_push(ppp);
1389                 while (!ppp->xmit_pending &&
1390                        (skb = skb_dequeue(&ppp->file.xq)))
1391                         ppp_send_frame(ppp, skb);
1392                 /* If there's no work left to do, tell the core net
1393                    code that we can accept some more. */
1394                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1395                         netif_wake_queue(ppp->dev);
1396                 else
1397                         netif_stop_queue(ppp->dev);
1398         }
1399         ppp_xmit_unlock(ppp);
1400 }
1401 
1402 static DEFINE_PER_CPU(int, ppp_xmit_recursion);
1403 
1404 static void ppp_xmit_process(struct ppp *ppp)
1405 {
1406         local_bh_disable();
1407 
1408         if (unlikely(__this_cpu_read(ppp_xmit_recursion)))
1409                 goto err;
1410 
1411         __this_cpu_inc(ppp_xmit_recursion);
1412         __ppp_xmit_process(ppp);
1413         __this_cpu_dec(ppp_xmit_recursion);
1414 
1415         local_bh_enable();
1416 
1417         return;
1418 
1419 err:
1420         local_bh_enable();
1421 
1422         if (net_ratelimit())
1423                 netdev_err(ppp->dev, "recursion detected\n");
1424 }
1425 
1426 static inline struct sk_buff *
1427 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1428 {
1429         struct sk_buff *new_skb;
1430         int len;
1431         int new_skb_size = ppp->dev->mtu +
1432                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1433         int compressor_skb_size = ppp->dev->mtu +
1434                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1435         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1436         if (!new_skb) {
1437                 if (net_ratelimit())
1438                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1439                 return NULL;
1440         }
1441         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1442                 skb_reserve(new_skb,
1443                             ppp->dev->hard_header_len - PPP_HDRLEN);
1444 
1445         /* compressor still expects A/C bytes in hdr */
1446         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1447                                    new_skb->data, skb->len + 2,
1448                                    compressor_skb_size);
1449         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1450                 consume_skb(skb);
1451                 skb = new_skb;
1452                 skb_put(skb, len);
1453                 skb_pull(skb, 2);       /* pull off A/C bytes */
1454         } else if (len == 0) {
1455                 /* didn't compress, or CCP not up yet */
1456                 consume_skb(new_skb);
1457                 new_skb = skb;
1458         } else {
1459                 /*
1460                  * (len < 0)
1461                  * MPPE requires that we do not send unencrypted
1462                  * frames.  The compressor will return -1 if we
1463                  * should drop the frame.  We cannot simply test
1464                  * the compress_proto because MPPE and MPPC share
1465                  * the same number.
1466                  */
1467                 if (net_ratelimit())
1468                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1469                 kfree_skb(skb);
1470                 consume_skb(new_skb);
1471                 new_skb = NULL;
1472         }
1473         return new_skb;
1474 }
1475 
1476 /*
1477  * Compress and send a frame.
1478  * The caller should have locked the xmit path,
1479  * and xmit_pending should be 0.
1480  */
1481 static void
1482 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1483 {
1484         int proto = PPP_PROTO(skb);
1485         struct sk_buff *new_skb;
1486         int len;
1487         unsigned char *cp;
1488 
1489         if (proto < 0x8000) {
1490 #ifdef CONFIG_PPP_FILTER
1491                 /* check if we should pass this packet */
1492                 /* the filter instructions are constructed assuming
1493                    a four-byte PPP header on each packet */
1494                 *skb_push(skb, 2) = 1;
1495                 if (ppp->pass_filter &&
1496                     BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1497                         if (ppp->debug & 1)
1498                                 netdev_printk(KERN_DEBUG, ppp->dev,
1499                                               "PPP: outbound frame "
1500                                               "not passed\n");
1501                         kfree_skb(skb);
1502                         return;
1503                 }
1504                 /* if this packet passes the active filter, record the time */
1505                 if (!(ppp->active_filter &&
1506                       BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1507                         ppp->last_xmit = jiffies;
1508                 skb_pull(skb, 2);
1509 #else
1510                 /* for data packets, record the time */
1511                 ppp->last_xmit = jiffies;
1512 #endif /* CONFIG_PPP_FILTER */
1513         }
1514 
1515         ++ppp->stats64.tx_packets;
1516         ppp->stats64.tx_bytes += skb->len - 2;
1517 
1518         switch (proto) {
1519         case PPP_IP:
1520                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1521                         break;
1522                 /* try to do VJ TCP header compression */
1523                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1524                                     GFP_ATOMIC);
1525                 if (!new_skb) {
1526                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1527                         goto drop;
1528                 }
1529                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1530                 cp = skb->data + 2;
1531                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1532                                     new_skb->data + 2, &cp,
1533                                     !(ppp->flags & SC_NO_TCP_CCID));
1534                 if (cp == skb->data + 2) {
1535                         /* didn't compress */
1536                         consume_skb(new_skb);
1537                 } else {
1538                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1539                                 proto = PPP_VJC_COMP;
1540                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1541                         } else {
1542                                 proto = PPP_VJC_UNCOMP;
1543                                 cp[0] = skb->data[2];
1544                         }
1545                         consume_skb(skb);
1546                         skb = new_skb;
1547                         cp = skb_put(skb, len + 2);
1548                         cp[0] = 0;
1549                         cp[1] = proto;
1550                 }
1551                 break;
1552 
1553         case PPP_CCP:
1554                 /* peek at outbound CCP frames */
1555                 ppp_ccp_peek(ppp, skb, 0);
1556                 break;
1557         }
1558 
1559         /* try to do packet compression */
1560         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1561             proto != PPP_LCP && proto != PPP_CCP) {
1562                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1563                         if (net_ratelimit())
1564                                 netdev_err(ppp->dev,
1565                                            "ppp: compression required but "
1566                                            "down - pkt dropped.\n");
1567                         goto drop;
1568                 }
1569                 skb = pad_compress_skb(ppp, skb);
1570                 if (!skb)
1571                         goto drop;
1572         }
1573 
1574         /*
1575          * If we are waiting for traffic (demand dialling),
1576          * queue it up for pppd to receive.
1577          */
1578         if (ppp->flags & SC_LOOP_TRAFFIC) {
1579                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1580                         goto drop;
1581                 skb_queue_tail(&ppp->file.rq, skb);
1582                 wake_up_interruptible(&ppp->file.rwait);
1583                 return;
1584         }
1585 
1586         ppp->xmit_pending = skb;
1587         ppp_push(ppp);
1588         return;
1589 
1590  drop:
1591         kfree_skb(skb);
1592         ++ppp->dev->stats.tx_errors;
1593 }
1594 
1595 /*
1596  * Try to send the frame in xmit_pending.
1597  * The caller should have the xmit path locked.
1598  */
1599 static void
1600 ppp_push(struct ppp *ppp)
1601 {
1602         struct list_head *list;
1603         struct channel *pch;
1604         struct sk_buff *skb = ppp->xmit_pending;
1605 
1606         if (!skb)
1607                 return;
1608 
1609         list = &ppp->channels;
1610         if (list_empty(list)) {
1611                 /* nowhere to send the packet, just drop it */
1612                 ppp->xmit_pending = NULL;
1613                 kfree_skb(skb);
1614                 return;
1615         }
1616 
1617         if ((ppp->flags & SC_MULTILINK) == 0) {
1618                 /* not doing multilink: send it down the first channel */
1619                 list = list->next;
1620                 pch = list_entry(list, struct channel, clist);
1621 
1622                 spin_lock_bh(&pch->downl);
1623                 if (pch->chan) {
1624                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1625                                 ppp->xmit_pending = NULL;
1626                 } else {
1627                         /* channel got unregistered */
1628                         kfree_skb(skb);
1629                         ppp->xmit_pending = NULL;
1630                 }
1631                 spin_unlock_bh(&pch->downl);
1632                 return;
1633         }
1634 
1635 #ifdef CONFIG_PPP_MULTILINK
1636         /* Multilink: fragment the packet over as many links
1637            as can take the packet at the moment. */
1638         if (!ppp_mp_explode(ppp, skb))
1639                 return;
1640 #endif /* CONFIG_PPP_MULTILINK */
1641 
1642         ppp->xmit_pending = NULL;
1643         kfree_skb(skb);
1644 }
1645 
1646 #ifdef CONFIG_PPP_MULTILINK
1647 static bool mp_protocol_compress __read_mostly = true;
1648 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1649 MODULE_PARM_DESC(mp_protocol_compress,
1650                  "compress protocol id in multilink fragments");
1651 
1652 /*
1653  * Divide a packet to be transmitted into fragments and
1654  * send them out the individual links.
1655  */
1656 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1657 {
1658         int len, totlen;
1659         int i, bits, hdrlen, mtu;
1660         int flen;
1661         int navail, nfree, nzero;
1662         int nbigger;
1663         int totspeed;
1664         int totfree;
1665         unsigned char *p, *q;
1666         struct list_head *list;
1667         struct channel *pch;
1668         struct sk_buff *frag;
1669         struct ppp_channel *chan;
1670 
1671         totspeed = 0; /*total bitrate of the bundle*/
1672         nfree = 0; /* # channels which have no packet already queued */
1673         navail = 0; /* total # of usable channels (not deregistered) */
1674         nzero = 0; /* number of channels with zero speed associated*/
1675         totfree = 0; /*total # of channels available and
1676                                   *having no queued packets before
1677                                   *starting the fragmentation*/
1678 
1679         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1680         i = 0;
1681         list_for_each_entry(pch, &ppp->channels, clist) {
1682                 if (pch->chan) {
1683                         pch->avail = 1;
1684                         navail++;
1685                         pch->speed = pch->chan->speed;
1686                 } else {
1687                         pch->avail = 0;
1688                 }
1689                 if (pch->avail) {
1690                         if (skb_queue_empty(&pch->file.xq) ||
1691                                 !pch->had_frag) {
1692                                         if (pch->speed == 0)
1693                                                 nzero++;
1694                                         else
1695                                                 totspeed += pch->speed;
1696 
1697                                         pch->avail = 2;
1698                                         ++nfree;
1699                                         ++totfree;
1700                                 }
1701                         if (!pch->had_frag && i < ppp->nxchan)
1702                                 ppp->nxchan = i;
1703                 }
1704                 ++i;
1705         }
1706         /*
1707          * Don't start sending this packet unless at least half of
1708          * the channels are free.  This gives much better TCP
1709          * performance if we have a lot of channels.
1710          */
1711         if (nfree == 0 || nfree < navail / 2)
1712                 return 0; /* can't take now, leave it in xmit_pending */
1713 
1714         /* Do protocol field compression */
1715         p = skb->data;
1716         len = skb->len;
1717         if (*p == 0 && mp_protocol_compress) {
1718                 ++p;
1719                 --len;
1720         }
1721 
1722         totlen = len;
1723         nbigger = len % nfree;
1724 
1725         /* skip to the channel after the one we last used
1726            and start at that one */
1727         list = &ppp->channels;
1728         for (i = 0; i < ppp->nxchan; ++i) {
1729                 list = list->next;
1730                 if (list == &ppp->channels) {
1731                         i = 0;
1732                         break;
1733                 }
1734         }
1735 
1736         /* create a fragment for each channel */
1737         bits = B;
1738         while (len > 0) {
1739                 list = list->next;
1740                 if (list == &ppp->channels) {
1741                         i = 0;
1742                         continue;
1743                 }
1744                 pch = list_entry(list, struct channel, clist);
1745                 ++i;
1746                 if (!pch->avail)
1747                         continue;
1748 
1749                 /*
1750                  * Skip this channel if it has a fragment pending already and
1751                  * we haven't given a fragment to all of the free channels.
1752                  */
1753                 if (pch->avail == 1) {
1754                         if (nfree > 0)
1755                                 continue;
1756                 } else {
1757                         pch->avail = 1;
1758                 }
1759 
1760                 /* check the channel's mtu and whether it is still attached. */
1761                 spin_lock_bh(&pch->downl);
1762                 if (pch->chan == NULL) {
1763                         /* can't use this channel, it's being deregistered */
1764                         if (pch->speed == 0)
1765                                 nzero--;
1766                         else
1767                                 totspeed -= pch->speed;
1768 
1769                         spin_unlock_bh(&pch->downl);
1770                         pch->avail = 0;
1771                         totlen = len;
1772                         totfree--;
1773                         nfree--;
1774                         if (--navail == 0)
1775                                 break;
1776                         continue;
1777                 }
1778 
1779                 /*
1780                 *if the channel speed is not set divide
1781                 *the packet evenly among the free channels;
1782                 *otherwise divide it according to the speed
1783                 *of the channel we are going to transmit on
1784                 */
1785                 flen = len;
1786                 if (nfree > 0) {
1787                         if (pch->speed == 0) {
1788                                 flen = len/nfree;
1789                                 if (nbigger > 0) {
1790                                         flen++;
1791                                         nbigger--;
1792                                 }
1793                         } else {
1794                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1795                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1796                                 if (nbigger > 0) {
1797                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1798                                         nbigger -= ((totfree - nzero)*pch->speed)/
1799                                                         totspeed;
1800                                 }
1801                         }
1802                         nfree--;
1803                 }
1804 
1805                 /*
1806                  *check if we are on the last channel or
1807                  *we exceded the length of the data to
1808                  *fragment
1809                  */
1810                 if ((nfree <= 0) || (flen > len))
1811                         flen = len;
1812                 /*
1813                  *it is not worth to tx on slow channels:
1814                  *in that case from the resulting flen according to the
1815                  *above formula will be equal or less than zero.
1816                  *Skip the channel in this case
1817                  */
1818                 if (flen <= 0) {
1819                         pch->avail = 2;
1820                         spin_unlock_bh(&pch->downl);
1821                         continue;
1822                 }
1823 
1824                 /*
1825                  * hdrlen includes the 2-byte PPP protocol field, but the
1826                  * MTU counts only the payload excluding the protocol field.
1827                  * (RFC1661 Section 2)
1828                  */
1829                 mtu = pch->chan->mtu - (hdrlen - 2);
1830                 if (mtu < 4)
1831                         mtu = 4;
1832                 if (flen > mtu)
1833                         flen = mtu;
1834                 if (flen == len)
1835                         bits |= E;
1836                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1837                 if (!frag)
1838                         goto noskb;
1839                 q = skb_put(frag, flen + hdrlen);
1840 
1841                 /* make the MP header */
1842                 put_unaligned_be16(PPP_MP, q);
1843                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1844                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1845                         q[3] = ppp->nxseq;
1846                 } else {
1847                         q[2] = bits;
1848                         q[3] = ppp->nxseq >> 16;
1849                         q[4] = ppp->nxseq >> 8;
1850                         q[5] = ppp->nxseq;
1851                 }
1852 
1853                 memcpy(q + hdrlen, p, flen);
1854 
1855                 /* try to send it down the channel */
1856                 chan = pch->chan;
1857                 if (!skb_queue_empty(&pch->file.xq) ||
1858                         !chan->ops->start_xmit(chan, frag))
1859                         skb_queue_tail(&pch->file.xq, frag);
1860                 pch->had_frag = 1;
1861                 p += flen;
1862                 len -= flen;
1863                 ++ppp->nxseq;
1864                 bits = 0;
1865                 spin_unlock_bh(&pch->downl);
1866         }
1867         ppp->nxchan = i;
1868 
1869         return 1;
1870 
1871  noskb:
1872         spin_unlock_bh(&pch->downl);
1873         if (ppp->debug & 1)
1874                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1875         ++ppp->dev->stats.tx_errors;
1876         ++ppp->nxseq;
1877         return 1;       /* abandon the frame */
1878 }
1879 #endif /* CONFIG_PPP_MULTILINK */
1880 
1881 /* Try to send data out on a channel */
1882 static void __ppp_channel_push(struct channel *pch)
1883 {
1884         struct sk_buff *skb;
1885         struct ppp *ppp;
1886 
1887         spin_lock_bh(&pch->downl);
1888         if (pch->chan) {
1889                 while (!skb_queue_empty(&pch->file.xq)) {
1890                         skb = skb_dequeue(&pch->file.xq);
1891                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1892                                 /* put the packet back and try again later */
1893                                 skb_queue_head(&pch->file.xq, skb);
1894                                 break;
1895                         }
1896                 }
1897         } else {
1898                 /* channel got deregistered */
1899                 skb_queue_purge(&pch->file.xq);
1900         }
1901         spin_unlock_bh(&pch->downl);
1902         /* see if there is anything from the attached unit to be sent */
1903         if (skb_queue_empty(&pch->file.xq)) {
1904                 read_lock_bh(&pch->upl);
1905                 ppp = pch->ppp;
1906                 if (ppp)
1907                         __ppp_xmit_process(ppp);
1908                 read_unlock_bh(&pch->upl);
1909         }
1910 }
1911 
1912 static void ppp_channel_push(struct channel *pch)
1913 {
1914         local_bh_disable();
1915 
1916         __this_cpu_inc(ppp_xmit_recursion);
1917         __ppp_channel_push(pch);
1918         __this_cpu_dec(ppp_xmit_recursion);
1919 
1920         local_bh_enable();
1921 }
1922 
1923 /*
1924  * Receive-side routines.
1925  */
1926 
1927 struct ppp_mp_skb_parm {
1928         u32             sequence;
1929         u8              BEbits;
1930 };
1931 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1932 
1933 static inline void
1934 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1935 {
1936         ppp_recv_lock(ppp);
1937         if (!ppp->closing)
1938                 ppp_receive_frame(ppp, skb, pch);
1939         else
1940                 kfree_skb(skb);
1941         ppp_recv_unlock(ppp);
1942 }
1943 
1944 void
1945 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1946 {
1947         struct channel *pch = chan->ppp;
1948         int proto;
1949 
1950         if (!pch) {
1951                 kfree_skb(skb);
1952                 return;
1953         }
1954 
1955         read_lock_bh(&pch->upl);
1956         if (!pskb_may_pull(skb, 2)) {
1957                 kfree_skb(skb);
1958                 if (pch->ppp) {
1959                         ++pch->ppp->dev->stats.rx_length_errors;
1960                         ppp_receive_error(pch->ppp);
1961                 }
1962                 goto done;
1963         }
1964 
1965         proto = PPP_PROTO(skb);
1966         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1967                 /* put it on the channel queue */
1968                 skb_queue_tail(&pch->file.rq, skb);
1969                 /* drop old frames if queue too long */
1970                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1971                        (skb = skb_dequeue(&pch->file.rq)))
1972                         kfree_skb(skb);
1973                 wake_up_interruptible(&pch->file.rwait);
1974         } else {
1975                 ppp_do_recv(pch->ppp, skb, pch);
1976         }
1977 
1978 done:
1979         read_unlock_bh(&pch->upl);
1980 }
1981 
1982 /* Put a 0-length skb in the receive queue as an error indication */
1983 void
1984 ppp_input_error(struct ppp_channel *chan, int code)
1985 {
1986         struct channel *pch = chan->ppp;
1987         struct sk_buff *skb;
1988 
1989         if (!pch)
1990                 return;
1991 
1992         read_lock_bh(&pch->upl);
1993         if (pch->ppp) {
1994                 skb = alloc_skb(0, GFP_ATOMIC);
1995                 if (skb) {
1996                         skb->len = 0;           /* probably unnecessary */
1997                         skb->cb[0] = code;
1998                         ppp_do_recv(pch->ppp, skb, pch);
1999                 }
2000         }
2001         read_unlock_bh(&pch->upl);
2002 }
2003 
2004 /*
2005  * We come in here to process a received frame.
2006  * The receive side of the ppp unit is locked.
2007  */
2008 static void
2009 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2010 {
2011         /* note: a 0-length skb is used as an error indication */
2012         if (skb->len > 0) {
2013                 skb_checksum_complete_unset(skb);
2014 #ifdef CONFIG_PPP_MULTILINK
2015                 /* XXX do channel-level decompression here */
2016                 if (PPP_PROTO(skb) == PPP_MP)
2017                         ppp_receive_mp_frame(ppp, skb, pch);
2018                 else
2019 #endif /* CONFIG_PPP_MULTILINK */
2020                         ppp_receive_nonmp_frame(ppp, skb);
2021         } else {
2022                 kfree_skb(skb);
2023                 ppp_receive_error(ppp);
2024         }
2025 }
2026 
2027 static void
2028 ppp_receive_error(struct ppp *ppp)
2029 {
2030         ++ppp->dev->stats.rx_errors;
2031         if (ppp->vj)
2032                 slhc_toss(ppp->vj);
2033 }
2034 
2035 static void
2036 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2037 {
2038         struct sk_buff *ns;
2039         int proto, len, npi;
2040 
2041         /*
2042          * Decompress the frame, if compressed.
2043          * Note that some decompressors need to see uncompressed frames
2044          * that come in as well as compressed frames.
2045          */
2046         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2047             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2048                 skb = ppp_decompress_frame(ppp, skb);
2049 
2050         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2051                 goto err;
2052 
2053         proto = PPP_PROTO(skb);
2054         switch (proto) {
2055         case PPP_VJC_COMP:
2056                 /* decompress VJ compressed packets */
2057                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2058                         goto err;
2059 
2060                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2061                         /* copy to a new sk_buff with more tailroom */
2062                         ns = dev_alloc_skb(skb->len + 128);
2063                         if (!ns) {
2064                                 netdev_err(ppp->dev, "PPP: no memory "
2065                                            "(VJ decomp)\n");
2066                                 goto err;
2067                         }
2068                         skb_reserve(ns, 2);
2069                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2070                         consume_skb(skb);
2071                         skb = ns;
2072                 }
2073                 else
2074                         skb->ip_summed = CHECKSUM_NONE;
2075 
2076                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2077                 if (len <= 0) {
2078                         netdev_printk(KERN_DEBUG, ppp->dev,
2079                                       "PPP: VJ decompression error\n");
2080                         goto err;
2081                 }
2082                 len += 2;
2083                 if (len > skb->len)
2084                         skb_put(skb, len - skb->len);
2085                 else if (len < skb->len)
2086                         skb_trim(skb, len);
2087                 proto = PPP_IP;
2088                 break;
2089 
2090         case PPP_VJC_UNCOMP:
2091                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2092                         goto err;
2093 
2094                 /* Until we fix the decompressor need to make sure
2095                  * data portion is linear.
2096                  */
2097                 if (!pskb_may_pull(skb, skb->len))
2098                         goto err;
2099 
2100                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2101                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2102                         goto err;
2103                 }
2104                 proto = PPP_IP;
2105                 break;
2106 
2107         case PPP_CCP:
2108                 ppp_ccp_peek(ppp, skb, 1);
2109                 break;
2110         }
2111 
2112         ++ppp->stats64.rx_packets;
2113         ppp->stats64.rx_bytes += skb->len - 2;
2114 
2115         npi = proto_to_npindex(proto);
2116         if (npi < 0) {
2117                 /* control or unknown frame - pass it to pppd */
2118                 skb_queue_tail(&ppp->file.rq, skb);
2119                 /* limit queue length by dropping old frames */
2120                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2121                        (skb = skb_dequeue(&ppp->file.rq)))
2122                         kfree_skb(skb);
2123                 /* wake up any process polling or blocking on read */
2124                 wake_up_interruptible(&ppp->file.rwait);
2125 
2126         } else {
2127                 /* network protocol frame - give it to the kernel */
2128 
2129 #ifdef CONFIG_PPP_FILTER
2130                 /* check if the packet passes the pass and active filters */
2131                 /* the filter instructions are constructed assuming
2132                    a four-byte PPP header on each packet */
2133                 if (ppp->pass_filter || ppp->active_filter) {
2134                         if (skb_unclone(skb, GFP_ATOMIC))
2135                                 goto err;
2136 
2137                         *skb_push(skb, 2) = 0;
2138                         if (ppp->pass_filter &&
2139                             BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2140                                 if (ppp->debug & 1)
2141                                         netdev_printk(KERN_DEBUG, ppp->dev,
2142                                                       "PPP: inbound frame "
2143                                                       "not passed\n");
2144                                 kfree_skb(skb);
2145                                 return;
2146                         }
2147                         if (!(ppp->active_filter &&
2148                               BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2149                                 ppp->last_recv = jiffies;
2150                         __skb_pull(skb, 2);
2151                 } else
2152 #endif /* CONFIG_PPP_FILTER */
2153                         ppp->last_recv = jiffies;
2154 
2155                 if ((ppp->dev->flags & IFF_UP) == 0 ||
2156                     ppp->npmode[npi] != NPMODE_PASS) {
2157                         kfree_skb(skb);
2158                 } else {
2159                         /* chop off protocol */
2160                         skb_pull_rcsum(skb, 2);
2161                         skb->dev = ppp->dev;
2162                         skb->protocol = htons(npindex_to_ethertype[npi]);
2163                         skb_reset_mac_header(skb);
2164                         skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2165                                                       dev_net(ppp->dev)));
2166                         netif_rx(skb);
2167                 }
2168         }
2169         return;
2170 
2171  err:
2172         kfree_skb(skb);
2173         ppp_receive_error(ppp);
2174 }
2175 
2176 static struct sk_buff *
2177 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2178 {
2179         int proto = PPP_PROTO(skb);
2180         struct sk_buff *ns;
2181         int len;
2182 
2183         /* Until we fix all the decompressor's need to make sure
2184          * data portion is linear.
2185          */
2186         if (!pskb_may_pull(skb, skb->len))
2187                 goto err;
2188 
2189         if (proto == PPP_COMP) {
2190                 int obuff_size;
2191 
2192                 switch(ppp->rcomp->compress_proto) {
2193                 case CI_MPPE:
2194                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
2195                         break;
2196                 default:
2197                         obuff_size = ppp->mru + PPP_HDRLEN;
2198                         break;
2199                 }
2200 
2201                 ns = dev_alloc_skb(obuff_size);
2202                 if (!ns) {
2203                         netdev_err(ppp->dev, "ppp_decompress_frame: "
2204                                    "no memory\n");
2205                         goto err;
2206                 }
2207                 /* the decompressor still expects the A/C bytes in the hdr */
2208                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2209                                 skb->len + 2, ns->data, obuff_size);
2210                 if (len < 0) {
2211                         /* Pass the compressed frame to pppd as an
2212                            error indication. */
2213                         if (len == DECOMP_FATALERROR)
2214                                 ppp->rstate |= SC_DC_FERROR;
2215                         kfree_skb(ns);
2216                         goto err;
2217                 }
2218 
2219                 consume_skb(skb);
2220                 skb = ns;
2221                 skb_put(skb, len);
2222                 skb_pull(skb, 2);       /* pull off the A/C bytes */
2223 
2224         } else {
2225                 /* Uncompressed frame - pass to decompressor so it
2226                    can update its dictionary if necessary. */
2227                 if (ppp->rcomp->incomp)
2228                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2229                                            skb->len + 2);
2230         }
2231 
2232         return skb;
2233 
2234  err:
2235         ppp->rstate |= SC_DC_ERROR;
2236         ppp_receive_error(ppp);
2237         return skb;
2238 }
2239 
2240 #ifdef CONFIG_PPP_MULTILINK
2241 /*
2242  * Receive a multilink frame.
2243  * We put it on the reconstruction queue and then pull off
2244  * as many completed frames as we can.
2245  */
2246 static void
2247 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2248 {
2249         u32 mask, seq;
2250         struct channel *ch;
2251         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2252 
2253         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2254                 goto err;               /* no good, throw it away */
2255 
2256         /* Decode sequence number and begin/end bits */
2257         if (ppp->flags & SC_MP_SHORTSEQ) {
2258                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2259                 mask = 0xfff;
2260         } else {
2261                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2262                 mask = 0xffffff;
2263         }
2264         PPP_MP_CB(skb)->BEbits = skb->data[2];
2265         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
2266 
2267         /*
2268          * Do protocol ID decompression on the first fragment of each packet.
2269          */
2270         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
2271                 *skb_push(skb, 1) = 0;
2272 
2273         /*
2274          * Expand sequence number to 32 bits, making it as close
2275          * as possible to ppp->minseq.
2276          */
2277         seq |= ppp->minseq & ~mask;
2278         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2279                 seq += mask + 1;
2280         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2281                 seq -= mask + 1;        /* should never happen */
2282         PPP_MP_CB(skb)->sequence = seq;
2283         pch->lastseq = seq;
2284 
2285         /*
2286          * If this packet comes before the next one we were expecting,
2287          * drop it.
2288          */
2289         if (seq_before(seq, ppp->nextseq)) {
2290                 kfree_skb(skb);
2291                 ++ppp->dev->stats.rx_dropped;
2292                 ppp_receive_error(ppp);
2293                 return;
2294         }
2295 
2296         /*
2297          * Reevaluate minseq, the minimum over all channels of the
2298          * last sequence number received on each channel.  Because of
2299          * the increasing sequence number rule, we know that any fragment
2300          * before `minseq' which hasn't arrived is never going to arrive.
2301          * The list of channels can't change because we have the receive
2302          * side of the ppp unit locked.
2303          */
2304         list_for_each_entry(ch, &ppp->channels, clist) {
2305                 if (seq_before(ch->lastseq, seq))
2306                         seq = ch->lastseq;
2307         }
2308         if (seq_before(ppp->minseq, seq))
2309                 ppp->minseq = seq;
2310 
2311         /* Put the fragment on the reconstruction queue */
2312         ppp_mp_insert(ppp, skb);
2313 
2314         /* If the queue is getting long, don't wait any longer for packets
2315            before the start of the queue. */
2316         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2317                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2318                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2319                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
2320         }
2321 
2322         /* Pull completed packets off the queue and receive them. */
2323         while ((skb = ppp_mp_reconstruct(ppp))) {
2324                 if (pskb_may_pull(skb, 2))
2325                         ppp_receive_nonmp_frame(ppp, skb);
2326                 else {
2327                         ++ppp->dev->stats.rx_length_errors;
2328                         kfree_skb(skb);
2329                         ppp_receive_error(ppp);
2330                 }
2331         }
2332 
2333         return;
2334 
2335  err:
2336         kfree_skb(skb);
2337         ppp_receive_error(ppp);
2338 }
2339 
2340 /*
2341  * Insert a fragment on the MP reconstruction queue.
2342  * The queue is ordered by increasing sequence number.
2343  */
2344 static void
2345 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2346 {
2347         struct sk_buff *p;
2348         struct sk_buff_head *list = &ppp->mrq;
2349         u32 seq = PPP_MP_CB(skb)->sequence;
2350 
2351         /* N.B. we don't need to lock the list lock because we have the
2352            ppp unit receive-side lock. */
2353         skb_queue_walk(list, p) {
2354                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2355                         break;
2356         }
2357         __skb_queue_before(list, p, skb);
2358 }
2359 
2360 /*
2361  * Reconstruct a packet from the MP fragment queue.
2362  * We go through increasing sequence numbers until we find a
2363  * complete packet, or we get to the sequence number for a fragment
2364  * which hasn't arrived but might still do so.
2365  */
2366 static struct sk_buff *
2367 ppp_mp_reconstruct(struct ppp *ppp)
2368 {
2369         u32 seq = ppp->nextseq;
2370         u32 minseq = ppp->minseq;
2371         struct sk_buff_head *list = &ppp->mrq;
2372         struct sk_buff *p, *tmp;
2373         struct sk_buff *head, *tail;
2374         struct sk_buff *skb = NULL;
2375         int lost = 0, len = 0;
2376 
2377         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2378                 return NULL;
2379         head = list->next;
2380         tail = NULL;
2381         skb_queue_walk_safe(list, p, tmp) {
2382         again:
2383                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2384                         /* this can't happen, anyway ignore the skb */
2385                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2386                                    "seq %u < %u\n",
2387                                    PPP_MP_CB(p)->sequence, seq);
2388                         __skb_unlink(p, list);
2389                         kfree_skb(p);
2390                         continue;
2391                 }
2392                 if (PPP_MP_CB(p)->sequence != seq) {
2393                         u32 oldseq;
2394                         /* Fragment `seq' is missing.  If it is after
2395                            minseq, it might arrive later, so stop here. */
2396                         if (seq_after(seq, minseq))
2397                                 break;
2398                         /* Fragment `seq' is lost, keep going. */
2399                         lost = 1;
2400                         oldseq = seq;
2401                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2402                                 minseq + 1: PPP_MP_CB(p)->sequence;
2403 
2404                         if (ppp->debug & 1)
2405                                 netdev_printk(KERN_DEBUG, ppp->dev,
2406                                               "lost frag %u..%u\n",
2407                                               oldseq, seq-1);
2408 
2409                         goto again;
2410                 }
2411 
2412                 /*
2413                  * At this point we know that all the fragments from
2414                  * ppp->nextseq to seq are either present or lost.
2415                  * Also, there are no complete packets in the queue
2416                  * that have no missing fragments and end before this
2417                  * fragment.
2418                  */
2419 
2420                 /* B bit set indicates this fragment starts a packet */
2421                 if (PPP_MP_CB(p)->BEbits & B) {
2422                         head = p;
2423                         lost = 0;
2424                         len = 0;
2425                 }
2426 
2427                 len += p->len;
2428 
2429                 /* Got a complete packet yet? */
2430                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2431                     (PPP_MP_CB(head)->BEbits & B)) {
2432                         if (len > ppp->mrru + 2) {
2433                                 ++ppp->dev->stats.rx_length_errors;
2434                                 netdev_printk(KERN_DEBUG, ppp->dev,
2435                                               "PPP: reconstructed packet"
2436                                               " is too long (%d)\n", len);
2437                         } else {
2438                                 tail = p;
2439                                 break;
2440                         }
2441                         ppp->nextseq = seq + 1;
2442                 }
2443 
2444                 /*
2445                  * If this is the ending fragment of a packet,
2446                  * and we haven't found a complete valid packet yet,
2447                  * we can discard up to and including this fragment.
2448                  */
2449                 if (PPP_MP_CB(p)->BEbits & E) {
2450                         struct sk_buff *tmp2;
2451 
2452                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2453                                 if (ppp->debug & 1)
2454                                         netdev_printk(KERN_DEBUG, ppp->dev,
2455                                                       "discarding frag %u\n",
2456                                                       PPP_MP_CB(p)->sequence);
2457                                 __skb_unlink(p, list);
2458                                 kfree_skb(p);
2459                         }
2460                         head = skb_peek(list);
2461                         if (!head)
2462                                 break;
2463                 }
2464                 ++seq;
2465         }
2466 
2467         /* If we have a complete packet, copy it all into one skb. */
2468         if (tail != NULL) {
2469                 /* If we have discarded any fragments,
2470                    signal a receive error. */
2471                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2472                         skb_queue_walk_safe(list, p, tmp) {
2473                                 if (p == head)
2474                                         break;
2475                                 if (ppp->debug & 1)
2476                                         netdev_printk(KERN_DEBUG, ppp->dev,
2477                                                       "discarding frag %u\n",
2478                                                       PPP_MP_CB(p)->sequence);
2479                                 __skb_unlink(p, list);
2480                                 kfree_skb(p);
2481                         }
2482 
2483                         if (ppp->debug & 1)
2484                                 netdev_printk(KERN_DEBUG, ppp->dev,
2485                                               "  missed pkts %u..%u\n",
2486                                               ppp->nextseq,
2487                                               PPP_MP_CB(head)->sequence-1);
2488                         ++ppp->dev->stats.rx_dropped;
2489                         ppp_receive_error(ppp);
2490                 }
2491 
2492                 skb = head;
2493                 if (head != tail) {
2494                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2495                         p = skb_queue_next(list, head);
2496                         __skb_unlink(skb, list);
2497                         skb_queue_walk_from_safe(list, p, tmp) {
2498                                 __skb_unlink(p, list);
2499                                 *fragpp = p;
2500                                 p->next = NULL;
2501                                 fragpp = &p->next;
2502 
2503                                 skb->len += p->len;
2504                                 skb->data_len += p->len;
2505                                 skb->truesize += p->truesize;
2506 
2507                                 if (p == tail)
2508                                         break;
2509                         }
2510                 } else {
2511                         __skb_unlink(skb, list);
2512                 }
2513 
2514                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2515         }
2516 
2517         return skb;
2518 }
2519 #endif /* CONFIG_PPP_MULTILINK */
2520 
2521 /*
2522  * Channel interface.
2523  */
2524 
2525 /* Create a new, unattached ppp channel. */
2526 int ppp_register_channel(struct ppp_channel *chan)
2527 {
2528         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2529 }
2530 
2531 /* Create a new, unattached ppp channel for specified net. */
2532 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2533 {
2534         struct channel *pch;
2535         struct ppp_net *pn;
2536 
2537         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2538         if (!pch)
2539                 return -ENOMEM;
2540 
2541         pn = ppp_pernet(net);
2542 
2543         pch->ppp = NULL;
2544         pch->chan = chan;
2545         pch->chan_net = get_net(net);
2546         chan->ppp = pch;
2547         init_ppp_file(&pch->file, CHANNEL);
2548         pch->file.hdrlen = chan->hdrlen;
2549 #ifdef CONFIG_PPP_MULTILINK
2550         pch->lastseq = -1;
2551 #endif /* CONFIG_PPP_MULTILINK */
2552         init_rwsem(&pch->chan_sem);
2553         spin_lock_init(&pch->downl);
2554         rwlock_init(&pch->upl);
2555 
2556         spin_lock_bh(&pn->all_channels_lock);
2557         pch->file.index = ++pn->last_channel_index;
2558         list_add(&pch->list, &pn->new_channels);
2559         atomic_inc(&channel_count);
2560         spin_unlock_bh(&pn->all_channels_lock);
2561 
2562         return 0;
2563 }
2564 
2565 /*
2566  * Return the index of a channel.
2567  */
2568 int ppp_channel_index(struct ppp_channel *chan)
2569 {
2570         struct channel *pch = chan->ppp;
2571 
2572         if (pch)
2573                 return pch->file.index;
2574         return -1;
2575 }
2576 
2577 /*
2578  * Return the PPP unit number to which a channel is connected.
2579  */
2580 int ppp_unit_number(struct ppp_channel *chan)
2581 {
2582         struct channel *pch = chan->ppp;
2583         int unit = -1;
2584 
2585         if (pch) {
2586                 read_lock_bh(&pch->upl);
2587                 if (pch->ppp)
2588                         unit = pch->ppp->file.index;
2589                 read_unlock_bh(&pch->upl);
2590         }
2591         return unit;
2592 }
2593 
2594 /*
2595  * Return the PPP device interface name of a channel.
2596  */
2597 char *ppp_dev_name(struct ppp_channel *chan)
2598 {
2599         struct channel *pch = chan->ppp;
2600         char *name = NULL;
2601 
2602         if (pch) {
2603                 read_lock_bh(&pch->upl);
2604                 if (pch->ppp && pch->ppp->dev)
2605                         name = pch->ppp->dev->name;
2606                 read_unlock_bh(&pch->upl);
2607         }
2608         return name;
2609 }
2610 
2611 
2612 /*
2613  * Disconnect a channel from the generic layer.
2614  * This must be called in process context.
2615  */
2616 void
2617 ppp_unregister_channel(struct ppp_channel *chan)
2618 {
2619         struct channel *pch = chan->ppp;
2620         struct ppp_net *pn;
2621 
2622         if (!pch)
2623                 return;         /* should never happen */
2624 
2625         chan->ppp = NULL;
2626 
2627         /*
2628          * This ensures that we have returned from any calls into the
2629          * the channel's start_xmit or ioctl routine before we proceed.
2630          */
2631         down_write(&pch->chan_sem);
2632         spin_lock_bh(&pch->downl);
2633         pch->chan = NULL;
2634         spin_unlock_bh(&pch->downl);
2635         up_write(&pch->chan_sem);
2636         ppp_disconnect_channel(pch);
2637 
2638         pn = ppp_pernet(pch->chan_net);
2639         spin_lock_bh(&pn->all_channels_lock);
2640         list_del(&pch->list);
2641         spin_unlock_bh(&pn->all_channels_lock);
2642 
2643         pch->file.dead = 1;
2644         wake_up_interruptible(&pch->file.rwait);
2645         if (atomic_dec_and_test(&pch->file.refcnt))
2646                 ppp_destroy_channel(pch);
2647 }
2648 
2649 /*
2650  * Callback from a channel when it can accept more to transmit.
2651  * This should be called at BH/softirq level, not interrupt level.
2652  */
2653 void
2654 ppp_output_wakeup(struct ppp_channel *chan)
2655 {
2656         struct channel *pch = chan->ppp;
2657 
2658         if (!pch)
2659                 return;
2660         ppp_channel_push(pch);
2661 }
2662 
2663 /*
2664  * Compression control.
2665  */
2666 
2667 /* Process the PPPIOCSCOMPRESS ioctl. */
2668 static int
2669 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2670 {
2671         int err;
2672         struct compressor *cp, *ocomp;
2673         struct ppp_option_data data;
2674         void *state, *ostate;
2675         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2676 
2677         err = -EFAULT;
2678         if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
2679                 goto out;
2680         if (data.length > CCP_MAX_OPTION_LENGTH)
2681                 goto out;
2682         if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
2683                 goto out;
2684 
2685         err = -EINVAL;
2686         if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
2687                 goto out;
2688 
2689         cp = try_then_request_module(
2690                 find_compressor(ccp_option[0]),
2691                 "ppp-compress-%d", ccp_option[0]);
2692         if (!cp)
2693                 goto out;
2694 
2695         err = -ENOBUFS;
2696         if (data.transmit) {
2697                 state = cp->comp_alloc(ccp_option, data.length);
2698                 if (state) {
2699                         ppp_xmit_lock(ppp);
2700                         ppp->xstate &= ~SC_COMP_RUN;
2701                         ocomp = ppp->xcomp;
2702                         ostate = ppp->xc_state;
2703                         ppp->xcomp = cp;
2704                         ppp->xc_state = state;
2705                         ppp_xmit_unlock(ppp);
2706                         if (ostate) {
2707                                 ocomp->comp_free(ostate);
2708                                 module_put(ocomp->owner);
2709                         }
2710                         err = 0;
2711                 } else
2712                         module_put(cp->owner);
2713 
2714         } else {
2715                 state = cp->decomp_alloc(ccp_option, data.length);
2716                 if (state) {
2717                         ppp_recv_lock(ppp);
2718                         ppp->rstate &= ~SC_DECOMP_RUN;
2719                         ocomp = ppp->rcomp;
2720                         ostate = ppp->rc_state;
2721                         ppp->rcomp = cp;
2722                         ppp->rc_state = state;
2723                         ppp_recv_unlock(ppp);
2724                         if (ostate) {
2725                                 ocomp->decomp_free(ostate);
2726                                 module_put(ocomp->owner);
2727                         }
2728                         err = 0;
2729                 } else
2730                         module_put(cp->owner);
2731         }
2732 
2733  out:
2734         return err;
2735 }
2736 
2737 /*
2738  * Look at a CCP packet and update our state accordingly.
2739  * We assume the caller has the xmit or recv path locked.
2740  */
2741 static void
2742 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2743 {
2744         unsigned char *dp;
2745         int len;
2746 
2747         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2748                 return; /* no header */
2749         dp = skb->data + 2;
2750 
2751         switch (CCP_CODE(dp)) {
2752         case CCP_CONFREQ:
2753 
2754                 /* A ConfReq starts negotiation of compression
2755                  * in one direction of transmission,
2756                  * and hence brings it down...but which way?
2757                  *
2758                  * Remember:
2759                  * A ConfReq indicates what the sender would like to receive
2760                  */
2761                 if(inbound)
2762                         /* He is proposing what I should send */
2763                         ppp->xstate &= ~SC_COMP_RUN;
2764                 else
2765                         /* I am proposing to what he should send */
2766                         ppp->rstate &= ~SC_DECOMP_RUN;
2767 
2768                 break;
2769 
2770         case CCP_TERMREQ:
2771         case CCP_TERMACK:
2772                 /*
2773                  * CCP is going down, both directions of transmission
2774                  */
2775                 ppp->rstate &= ~SC_DECOMP_RUN;
2776                 ppp->xstate &= ~SC_COMP_RUN;
2777                 break;
2778 
2779         case CCP_CONFACK:
2780                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2781                         break;
2782                 len = CCP_LENGTH(dp);
2783                 if (!pskb_may_pull(skb, len + 2))
2784                         return;         /* too short */
2785                 dp += CCP_HDRLEN;
2786                 len -= CCP_HDRLEN;
2787                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2788                         break;
2789                 if (inbound) {
2790                         /* we will start receiving compressed packets */
2791                         if (!ppp->rc_state)
2792                                 break;
2793                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2794                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2795                                 ppp->rstate |= SC_DECOMP_RUN;
2796                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2797                         }
2798                 } else {
2799                         /* we will soon start sending compressed packets */
2800                         if (!ppp->xc_state)
2801                                 break;
2802                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2803                                         ppp->file.index, 0, ppp->debug))
2804                                 ppp->xstate |= SC_COMP_RUN;
2805                 }
2806                 break;
2807 
2808         case CCP_RESETACK:
2809                 /* reset the [de]compressor */
2810                 if ((ppp->flags & SC_CCP_UP) == 0)
2811                         break;
2812                 if (inbound) {
2813                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2814                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2815                                 ppp->rstate &= ~SC_DC_ERROR;
2816                         }
2817                 } else {
2818                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2819                                 ppp->xcomp->comp_reset(ppp->xc_state);
2820                 }
2821                 break;
2822         }
2823 }
2824 
2825 /* Free up compression resources. */
2826 static void
2827 ppp_ccp_closed(struct ppp *ppp)
2828 {
2829         void *xstate, *rstate;
2830         struct compressor *xcomp, *rcomp;
2831 
2832         ppp_lock(ppp);
2833         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2834         ppp->xstate = 0;
2835         xcomp = ppp->xcomp;
2836         xstate = ppp->xc_state;
2837         ppp->xc_state = NULL;
2838         ppp->rstate = 0;
2839         rcomp = ppp->rcomp;
2840         rstate = ppp->rc_state;
2841         ppp->rc_state = NULL;
2842         ppp_unlock(ppp);
2843 
2844         if (xstate) {
2845                 xcomp->comp_free(xstate);
2846                 module_put(xcomp->owner);
2847         }
2848         if (rstate) {
2849                 rcomp->decomp_free(rstate);
2850                 module_put(rcomp->owner);
2851         }
2852 }
2853 
2854 /* List of compressors. */
2855 static LIST_HEAD(compressor_list);
2856 static DEFINE_SPINLOCK(compressor_list_lock);
2857 
2858 struct compressor_entry {
2859         struct list_head list;
2860         struct compressor *comp;
2861 };
2862 
2863 static struct compressor_entry *
2864 find_comp_entry(int proto)
2865 {
2866         struct compressor_entry *ce;
2867 
2868         list_for_each_entry(ce, &compressor_list, list) {
2869                 if (ce->comp->compress_proto == proto)
2870                         return ce;
2871         }
2872         return NULL;
2873 }
2874 
2875 /* Register a compressor */
2876 int
2877 ppp_register_compressor(struct compressor *cp)
2878 {
2879         struct compressor_entry *ce;
2880         int ret;
2881         spin_lock(&compressor_list_lock);
2882         ret = -EEXIST;
2883         if (find_comp_entry(cp->compress_proto))
2884                 goto out;
2885         ret = -ENOMEM;
2886         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2887         if (!ce)
2888                 goto out;
2889         ret = 0;
2890         ce->comp = cp;
2891         list_add(&ce->list, &compressor_list);
2892  out:
2893         spin_unlock(&compressor_list_lock);
2894         return ret;
2895 }
2896 
2897 /* Unregister a compressor */
2898 void
2899 ppp_unregister_compressor(struct compressor *cp)
2900 {
2901         struct compressor_entry *ce;
2902 
2903         spin_lock(&compressor_list_lock);
2904         ce = find_comp_entry(cp->compress_proto);
2905         if (ce && ce->comp == cp) {
2906                 list_del(&ce->list);
2907                 kfree(ce);
2908         }
2909         spin_unlock(&compressor_list_lock);
2910 }
2911 
2912 /* Find a compressor. */
2913 static struct compressor *
2914 find_compressor(int type)
2915 {
2916         struct compressor_entry *ce;
2917         struct compressor *cp = NULL;
2918 
2919         spin_lock(&compressor_list_lock);
2920         ce = find_comp_entry(type);
2921         if (ce) {
2922                 cp = ce->comp;
2923                 if (!try_module_get(cp->owner))
2924                         cp = NULL;
2925         }
2926         spin_unlock(&compressor_list_lock);
2927         return cp;
2928 }
2929 
2930 /*
2931  * Miscelleneous stuff.
2932  */
2933 
2934 static void
2935 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2936 {
2937         struct slcompress *vj = ppp->vj;
2938 
2939         memset(st, 0, sizeof(*st));
2940         st->p.ppp_ipackets = ppp->stats64.rx_packets;
2941         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2942         st->p.ppp_ibytes = ppp->stats64.rx_bytes;
2943         st->p.ppp_opackets = ppp->stats64.tx_packets;
2944         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2945         st->p.ppp_obytes = ppp->stats64.tx_bytes;
2946         if (!vj)
2947                 return;
2948         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2949         st->vj.vjs_compressed = vj->sls_o_compressed;
2950         st->vj.vjs_searches = vj->sls_o_searches;
2951         st->vj.vjs_misses = vj->sls_o_misses;
2952         st->vj.vjs_errorin = vj->sls_i_error;
2953         st->vj.vjs_tossed = vj->sls_i_tossed;
2954         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2955         st->vj.vjs_compressedin = vj->sls_i_compressed;
2956 }
2957 
2958 /*
2959  * Stuff for handling the lists of ppp units and channels
2960  * and for initialization.
2961  */
2962 
2963 /*
2964  * Create a new ppp interface unit.  Fails if it can't allocate memory
2965  * or if there is already a unit with the requested number.
2966  * unit == -1 means allocate a new number.
2967  */
2968 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
2969 {
2970         struct ppp_config conf = {
2971                 .file = file,
2972                 .unit = *unit,
2973                 .ifname_is_set = false,
2974         };
2975         struct net_device *dev;
2976         struct ppp *ppp;
2977         int err;
2978 
2979         dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
2980         if (!dev) {
2981                 err = -ENOMEM;
2982                 goto err;
2983         }
2984         dev_net_set(dev, net);
2985         dev->rtnl_link_ops = &ppp_link_ops;
2986 
2987         rtnl_lock();
2988 
2989         err = ppp_dev_configure(net, dev, &conf);
2990         if (err < 0)
2991                 goto err_dev;
2992         ppp = netdev_priv(dev);
2993         *unit = ppp->file.index;
2994 
2995         rtnl_unlock();
2996 
2997         return 0;
2998 
2999 err_dev:
3000         rtnl_unlock();
3001         free_netdev(dev);
3002 err:
3003         return err;
3004 }
3005 
3006 /*
3007  * Initialize a ppp_file structure.
3008  */
3009 static void
3010 init_ppp_file(struct ppp_file *pf, int kind)
3011 {
3012         pf->kind = kind;
3013         skb_queue_head_init(&pf->xq);
3014         skb_queue_head_init(&pf->rq);
3015         atomic_set(&pf->refcnt, 1);
3016         init_waitqueue_head(&pf->rwait);
3017 }
3018 
3019 /*
3020  * Free the memory used by a ppp unit.  This is only called once
3021  * there are no channels connected to the unit and no file structs
3022  * that reference the unit.
3023  */
3024 static void ppp_destroy_interface(struct ppp *ppp)
3025 {
3026         atomic_dec(&ppp_unit_count);
3027 
3028         if (!ppp->file.dead || ppp->n_channels) {
3029                 /* "can't happen" */
3030                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3031                            "but dead=%d n_channels=%d !\n",
3032                            ppp, ppp->file.dead, ppp->n_channels);
3033                 return;
3034         }
3035 
3036         ppp_ccp_closed(ppp);
3037         if (ppp->vj) {
3038                 slhc_free(ppp->vj);
3039                 ppp->vj = NULL;
3040         }
3041         skb_queue_purge(&ppp->file.xq);
3042         skb_queue_purge(&ppp->file.rq);
3043 #ifdef CONFIG_PPP_MULTILINK
3044         skb_queue_purge(&ppp->mrq);
3045 #endif /* CONFIG_PPP_MULTILINK */
3046 #ifdef CONFIG_PPP_FILTER
3047         if (ppp->pass_filter) {
3048                 bpf_prog_destroy(ppp->pass_filter);
3049                 ppp->pass_filter = NULL;
3050         }
3051 
3052         if (ppp->active_filter) {
3053                 bpf_prog_destroy(ppp->active_filter);
3054                 ppp->active_filter = NULL;
3055         }
3056 #endif /* CONFIG_PPP_FILTER */
3057 
3058         kfree_skb(ppp->xmit_pending);
3059 
3060         free_netdev(ppp->dev);
3061 }
3062 
3063 /*
3064  * Locate an existing ppp unit.
3065  * The caller should have locked the all_ppp_mutex.
3066  */
3067 static struct ppp *
3068 ppp_find_unit(struct ppp_net *pn, int unit)
3069 {
3070         return unit_find(&pn->units_idr, unit);
3071 }
3072 
3073 /*
3074  * Locate an existing ppp channel.
3075  * The caller should have locked the all_channels_lock.
3076  * First we look in the new_channels list, then in the
3077  * all_channels list.  If found in the new_channels list,
3078  * we move it to the all_channels list.  This is for speed
3079  * when we have a lot of channels in use.
3080  */
3081 static struct channel *
3082 ppp_find_channel(struct ppp_net *pn, int unit)
3083 {
3084         struct channel *pch;
3085 
3086         list_for_each_entry(pch, &pn->new_channels, list) {
3087                 if (pch->file.index == unit) {
3088                         list_move(&pch->list, &pn->all_channels);
3089                         return pch;
3090                 }
3091         }
3092 
3093         list_for_each_entry(pch, &pn->all_channels, list) {
3094                 if (pch->file.index == unit)
3095                         return pch;
3096         }
3097 
3098         return NULL;
3099 }
3100 
3101 /*
3102  * Connect a PPP channel to a PPP interface unit.
3103  */
3104 static int
3105 ppp_connect_channel(struct channel *pch, int unit)
3106 {
3107         struct ppp *ppp;
3108         struct ppp_net *pn;
3109         int ret = -ENXIO;
3110         int hdrlen;
3111 
3112         pn = ppp_pernet(pch->chan_net);
3113 
3114         mutex_lock(&pn->all_ppp_mutex);
3115         ppp = ppp_find_unit(pn, unit);
3116         if (!ppp)
3117                 goto out;
3118         write_lock_bh(&pch->upl);
3119         ret = -EINVAL;
3120         if (pch->ppp)
3121                 goto outl;
3122 
3123         ppp_lock(ppp);
3124         if (pch->file.hdrlen > ppp->file.hdrlen)
3125                 ppp->file.hdrlen = pch->file.hdrlen;
3126         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
3127         if (hdrlen > ppp->dev->hard_header_len)
3128                 ppp->dev->hard_header_len = hdrlen;
3129         list_add_tail(&pch->clist, &ppp->channels);
3130         ++ppp->n_channels;
3131         pch->ppp = ppp;
3132         atomic_inc(&ppp->file.refcnt);
3133         ppp_unlock(ppp);
3134         ret = 0;
3135 
3136  outl:
3137         write_unlock_bh(&pch->upl);
3138  out:
3139         mutex_unlock(&pn->all_ppp_mutex);
3140         return ret;
3141 }
3142 
3143 /*
3144  * Disconnect a channel from its ppp unit.
3145  */
3146 static int
3147 ppp_disconnect_channel(struct channel *pch)
3148 {
3149         struct ppp *ppp;
3150         int err = -EINVAL;
3151 
3152         write_lock_bh(&pch->upl);
3153         ppp = pch->ppp;
3154         pch->ppp = NULL;
3155         write_unlock_bh(&pch->upl);
3156         if (ppp) {
3157                 /* remove it from the ppp unit's list */
3158                 ppp_lock(ppp);
3159                 list_del(&pch->clist);
3160                 if (--ppp->n_channels == 0)
3161                         wake_up_interruptible(&ppp->file.rwait);
3162                 ppp_unlock(ppp);
3163                 if (atomic_dec_and_test(&ppp->file.refcnt))
3164                         ppp_destroy_interface(ppp);
3165                 err = 0;
3166         }
3167         return err;
3168 }
3169 
3170 /*
3171  * Free up the resources used by a ppp channel.
3172  */
3173 static void ppp_destroy_channel(struct channel *pch)
3174 {
3175         put_net(pch->chan_net);
3176         pch->chan_net = NULL;
3177 
3178         atomic_dec(&channel_count);
3179 
3180         if (!pch->file.dead) {
3181                 /* "can't happen" */
3182                 pr_err("ppp: destroying undead channel %p !\n", pch);
3183                 return;
3184         }
3185         skb_queue_purge(&pch->file.xq);
3186         skb_queue_purge(&pch->file.rq);
3187         kfree(pch);
3188 }
3189 
3190 static void __exit ppp_cleanup(void)
3191 {
3192         /* should never happen */
3193         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3194                 pr_err("PPP: removing module but units remain!\n");
3195         rtnl_link_unregister(&ppp_link_ops);
3196         unregister_chrdev(PPP_MAJOR, "ppp");
3197         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3198         class_destroy(ppp_class);
3199         unregister_pernet_device(&ppp_net_ops);
3200 }
3201 
3202 /*
3203  * Units handling. Caller must protect concurrent access
3204  * by holding all_ppp_mutex
3205  */
3206 
3207 /* associate pointer with specified number */
3208 static int unit_set(struct idr *p, void *ptr, int n)
3209 {
3210         int unit;
3211 
3212         unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3213         if (unit == -ENOSPC)
3214                 unit = -EINVAL;
3215         return unit;
3216 }
3217 
3218 /* get new free unit number and associate pointer with it */
3219 static int unit_get(struct idr *p, void *ptr)
3220 {
3221         return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
3222 }
3223 
3224 /* put unit number back to a pool */
3225 static void unit_put(struct idr *p, int n)
3226 {
3227         idr_remove(p, n);
3228 }
3229 
3230 /* get pointer associated with the number */
3231 static void *unit_find(struct idr *p, int n)
3232 {
3233         return idr_find(p, n);
3234 }
3235 
3236 /* Module/initialization stuff */
3237 
3238 module_init(ppp_init);
3239 module_exit(ppp_cleanup);
3240 
3241 EXPORT_SYMBOL(ppp_register_net_channel);
3242 EXPORT_SYMBOL(ppp_register_channel);
3243 EXPORT_SYMBOL(ppp_unregister_channel);
3244 EXPORT_SYMBOL(ppp_channel_index);
3245 EXPORT_SYMBOL(ppp_unit_number);
3246 EXPORT_SYMBOL(ppp_dev_name);
3247 EXPORT_SYMBOL(ppp_input);
3248 EXPORT_SYMBOL(ppp_input_error);
3249 EXPORT_SYMBOL(ppp_output_wakeup);
3250 EXPORT_SYMBOL(ppp_register_compressor);
3251 EXPORT_SYMBOL(ppp_unregister_compressor);
3252 MODULE_LICENSE("GPL");
3253 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3254 MODULE_ALIAS_RTNL_LINK("ppp");
3255 MODULE_ALIAS("devname:ppp");
3256 

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