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