Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6.git] / drivers / net / 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 <net/slhc_vj.h>
50 #include <asm/atomic.h>
51
52 #include <linux/nsproxy.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55
56 #define PPP_VERSION     "2.4.2"
57
58 /*
59  * Network protocols we support.
60  */
61 #define NP_IP   0               /* Internet Protocol V4 */
62 #define NP_IPV6 1               /* Internet Protocol V6 */
63 #define NP_IPX  2               /* IPX protocol */
64 #define NP_AT   3               /* Appletalk protocol */
65 #define NP_MPLS_UC 4            /* MPLS unicast */
66 #define NP_MPLS_MC 5            /* MPLS multicast */
67 #define NUM_NP  6               /* Number of NPs. */
68
69 #define MPHDRLEN        6       /* multilink protocol header length */
70 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
71
72 /*
73  * An instance of /dev/ppp can be associated with either a ppp
74  * interface unit or a ppp channel.  In both cases, file->private_data
75  * points to one of these.
76  */
77 struct ppp_file {
78         enum {
79                 INTERFACE=1, CHANNEL
80         }               kind;
81         struct sk_buff_head xq;         /* pppd transmit queue */
82         struct sk_buff_head rq;         /* receive queue for pppd */
83         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
84         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
85         int             hdrlen;         /* space to leave for headers */
86         int             index;          /* interface unit / channel number */
87         int             dead;           /* unit/channel has been shut down */
88 };
89
90 #define PF_TO_X(pf, X)          container_of(pf, X, file)
91
92 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
93 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
94
95 /*
96  * Data structure describing one ppp unit.
97  * A ppp unit corresponds to a ppp network interface device
98  * and represents a multilink bundle.
99  * It can have 0 or more ppp channels connected to it.
100  */
101 struct ppp {
102         struct ppp_file file;           /* stuff for read/write/poll 0 */
103         struct file     *owner;         /* file that owns this unit 48 */
104         struct list_head channels;      /* list of attached channels 4c */
105         int             n_channels;     /* how many channels are attached 54 */
106         spinlock_t      rlock;          /* lock for receive side 58 */
107         spinlock_t      wlock;          /* lock for transmit side 5c */
108         int             mru;            /* max receive unit 60 */
109         unsigned int    flags;          /* control bits 64 */
110         unsigned int    xstate;         /* transmit state bits 68 */
111         unsigned int    rstate;         /* receive state bits 6c */
112         int             debug;          /* debug flags 70 */
113         struct slcompress *vj;          /* state for VJ header compression */
114         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
115         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
116         struct compressor *xcomp;       /* transmit packet compressor 8c */
117         void            *xc_state;      /* its internal state 90 */
118         struct compressor *rcomp;       /* receive decompressor 94 */
119         void            *rc_state;      /* its internal state 98 */
120         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
121         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
122         struct net_device *dev;         /* network interface device a4 */
123         int             closing;        /* is device closing down? a8 */
124 #ifdef CONFIG_PPP_MULTILINK
125         int             nxchan;         /* next channel to send something on */
126         u32             nxseq;          /* next sequence number to send */
127         int             mrru;           /* MP: max reconst. receive unit */
128         u32             nextseq;        /* MP: seq no of next packet */
129         u32             minseq;         /* MP: min of most recent seqnos */
130         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
131 #endif /* CONFIG_PPP_MULTILINK */
132 #ifdef CONFIG_PPP_FILTER
133         struct sock_filter *pass_filter;        /* filter for packets to pass */
134         struct sock_filter *active_filter;/* filter for pkts to reset idle */
135         unsigned pass_len, active_len;
136 #endif /* CONFIG_PPP_FILTER */
137         struct net      *ppp_net;       /* the net we belong to */
138 };
139
140 /*
141  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
142  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
143  * SC_MUST_COMP
144  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
145  * Bits in xstate: SC_COMP_RUN
146  */
147 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
148                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
149                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
150
151 /*
152  * Private data structure for each channel.
153  * This includes the data structure used for multilink.
154  */
155 struct channel {
156         struct ppp_file file;           /* stuff for read/write/poll */
157         struct list_head list;          /* link in all/new_channels list */
158         struct ppp_channel *chan;       /* public channel data structure */
159         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
160         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
161         struct ppp      *ppp;           /* ppp unit we're connected to */
162         struct net      *chan_net;      /* the net channel belongs to */
163         struct list_head clist;         /* link in list of channels per unit */
164         rwlock_t        upl;            /* protects `ppp' */
165 #ifdef CONFIG_PPP_MULTILINK
166         u8              avail;          /* flag used in multilink stuff */
167         u8              had_frag;       /* >= 1 fragments have been sent */
168         u32             lastseq;        /* MP: last sequence # received */
169         int             speed;          /* speed of the corresponding ppp channel*/
170 #endif /* CONFIG_PPP_MULTILINK */
171 };
172
173 /*
174  * SMP locking issues:
175  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
176  * list and the ppp.n_channels field, you need to take both locks
177  * before you modify them.
178  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
179  * channel.downl.
180  */
181
182 static DEFINE_MUTEX(ppp_mutex);
183 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
184 static atomic_t channel_count = ATOMIC_INIT(0);
185
186 /* per-net private data for this module */
187 static int ppp_net_id __read_mostly;
188 struct ppp_net {
189         /* units to ppp mapping */
190         struct idr units_idr;
191
192         /*
193          * all_ppp_mutex protects the units_idr mapping.
194          * It also ensures that finding a ppp unit in the units_idr
195          * map and updating its file.refcnt field is atomic.
196          */
197         struct mutex all_ppp_mutex;
198
199         /* channels */
200         struct list_head all_channels;
201         struct list_head new_channels;
202         int last_channel_index;
203
204         /*
205          * all_channels_lock protects all_channels and
206          * last_channel_index, and the atomicity of find
207          * a channel and updating its file.refcnt field.
208          */
209         spinlock_t all_channels_lock;
210 };
211
212 /* Get the PPP protocol number from a skb */
213 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
214
215 /* We limit the length of ppp->file.rq to this (arbitrary) value */
216 #define PPP_MAX_RQLEN   32
217
218 /*
219  * Maximum number of multilink fragments queued up.
220  * This has to be large enough to cope with the maximum latency of
221  * the slowest channel relative to the others.  Strictly it should
222  * depend on the number of channels and their characteristics.
223  */
224 #define PPP_MP_MAX_QLEN 128
225
226 /* Multilink header bits. */
227 #define B       0x80            /* this fragment begins a packet */
228 #define E       0x40            /* this fragment ends a packet */
229
230 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
231 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
232 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
233
234 /* Prototypes. */
235 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
236                         struct file *file, unsigned int cmd, unsigned long arg);
237 static void ppp_xmit_process(struct ppp *ppp);
238 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
239 static void ppp_push(struct ppp *ppp);
240 static void ppp_channel_push(struct channel *pch);
241 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
242                               struct channel *pch);
243 static void ppp_receive_error(struct ppp *ppp);
244 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
245 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
246                                             struct sk_buff *skb);
247 #ifdef CONFIG_PPP_MULTILINK
248 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
249                                 struct channel *pch);
250 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
251 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
252 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
253 #endif /* CONFIG_PPP_MULTILINK */
254 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
255 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
256 static void ppp_ccp_closed(struct ppp *ppp);
257 static struct compressor *find_compressor(int type);
258 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
259 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
260 static void init_ppp_file(struct ppp_file *pf, int kind);
261 static void ppp_shutdown_interface(struct ppp *ppp);
262 static void ppp_destroy_interface(struct ppp *ppp);
263 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
264 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
265 static int ppp_connect_channel(struct channel *pch, int unit);
266 static int ppp_disconnect_channel(struct channel *pch);
267 static void ppp_destroy_channel(struct channel *pch);
268 static int unit_get(struct idr *p, void *ptr);
269 static int unit_set(struct idr *p, void *ptr, int n);
270 static void unit_put(struct idr *p, int n);
271 static void *unit_find(struct idr *p, int n);
272
273 static struct class *ppp_class;
274
275 /* per net-namespace data */
276 static inline struct ppp_net *ppp_pernet(struct net *net)
277 {
278         BUG_ON(!net);
279
280         return net_generic(net, ppp_net_id);
281 }
282
283 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
284 static inline int proto_to_npindex(int proto)
285 {
286         switch (proto) {
287         case PPP_IP:
288                 return NP_IP;
289         case PPP_IPV6:
290                 return NP_IPV6;
291         case PPP_IPX:
292                 return NP_IPX;
293         case PPP_AT:
294                 return NP_AT;
295         case PPP_MPLS_UC:
296                 return NP_MPLS_UC;
297         case PPP_MPLS_MC:
298                 return NP_MPLS_MC;
299         }
300         return -EINVAL;
301 }
302
303 /* Translates an NP index into a PPP protocol number */
304 static const int npindex_to_proto[NUM_NP] = {
305         PPP_IP,
306         PPP_IPV6,
307         PPP_IPX,
308         PPP_AT,
309         PPP_MPLS_UC,
310         PPP_MPLS_MC,
311 };
312
313 /* Translates an ethertype into an NP index */
314 static inline int ethertype_to_npindex(int ethertype)
315 {
316         switch (ethertype) {
317         case ETH_P_IP:
318                 return NP_IP;
319         case ETH_P_IPV6:
320                 return NP_IPV6;
321         case ETH_P_IPX:
322                 return NP_IPX;
323         case ETH_P_PPPTALK:
324         case ETH_P_ATALK:
325                 return NP_AT;
326         case ETH_P_MPLS_UC:
327                 return NP_MPLS_UC;
328         case ETH_P_MPLS_MC:
329                 return NP_MPLS_MC;
330         }
331         return -1;
332 }
333
334 /* Translates an NP index into an ethertype */
335 static const int npindex_to_ethertype[NUM_NP] = {
336         ETH_P_IP,
337         ETH_P_IPV6,
338         ETH_P_IPX,
339         ETH_P_PPPTALK,
340         ETH_P_MPLS_UC,
341         ETH_P_MPLS_MC,
342 };
343
344 /*
345  * Locking shorthand.
346  */
347 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
348 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
349 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
350 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
351 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
352                                      ppp_recv_lock(ppp); } while (0)
353 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
354                                      ppp_xmit_unlock(ppp); } while (0)
355
356 /*
357  * /dev/ppp device routines.
358  * The /dev/ppp device is used by pppd to control the ppp unit.
359  * It supports the read, write, ioctl and poll functions.
360  * Open instances of /dev/ppp can be in one of three states:
361  * unattached, attached to a ppp unit, or attached to a ppp channel.
362  */
363 static int ppp_open(struct inode *inode, struct file *file)
364 {
365         /*
366          * This could (should?) be enforced by the permissions on /dev/ppp.
367          */
368         if (!capable(CAP_NET_ADMIN))
369                 return -EPERM;
370         return 0;
371 }
372
373 static int ppp_release(struct inode *unused, struct file *file)
374 {
375         struct ppp_file *pf = file->private_data;
376         struct ppp *ppp;
377
378         if (pf) {
379                 file->private_data = NULL;
380                 if (pf->kind == INTERFACE) {
381                         ppp = PF_TO_PPP(pf);
382                         if (file == ppp->owner)
383                                 ppp_shutdown_interface(ppp);
384                 }
385                 if (atomic_dec_and_test(&pf->refcnt)) {
386                         switch (pf->kind) {
387                         case INTERFACE:
388                                 ppp_destroy_interface(PF_TO_PPP(pf));
389                                 break;
390                         case CHANNEL:
391                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
392                                 break;
393                         }
394                 }
395         }
396         return 0;
397 }
398
399 static ssize_t ppp_read(struct file *file, char __user *buf,
400                         size_t count, loff_t *ppos)
401 {
402         struct ppp_file *pf = file->private_data;
403         DECLARE_WAITQUEUE(wait, current);
404         ssize_t ret;
405         struct sk_buff *skb = NULL;
406         struct iovec iov;
407
408         ret = count;
409
410         if (!pf)
411                 return -ENXIO;
412         add_wait_queue(&pf->rwait, &wait);
413         for (;;) {
414                 set_current_state(TASK_INTERRUPTIBLE);
415                 skb = skb_dequeue(&pf->rq);
416                 if (skb)
417                         break;
418                 ret = 0;
419                 if (pf->dead)
420                         break;
421                 if (pf->kind == INTERFACE) {
422                         /*
423                          * Return 0 (EOF) on an interface that has no
424                          * channels connected, unless it is looping
425                          * network traffic (demand mode).
426                          */
427                         struct ppp *ppp = PF_TO_PPP(pf);
428                         if (ppp->n_channels == 0 &&
429                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
430                                 break;
431                 }
432                 ret = -EAGAIN;
433                 if (file->f_flags & O_NONBLOCK)
434                         break;
435                 ret = -ERESTARTSYS;
436                 if (signal_pending(current))
437                         break;
438                 schedule();
439         }
440         set_current_state(TASK_RUNNING);
441         remove_wait_queue(&pf->rwait, &wait);
442
443         if (!skb)
444                 goto out;
445
446         ret = -EOVERFLOW;
447         if (skb->len > count)
448                 goto outf;
449         ret = -EFAULT;
450         iov.iov_base = buf;
451         iov.iov_len = count;
452         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
453                 goto outf;
454         ret = skb->len;
455
456  outf:
457         kfree_skb(skb);
458  out:
459         return ret;
460 }
461
462 static ssize_t ppp_write(struct file *file, const char __user *buf,
463                          size_t count, loff_t *ppos)
464 {
465         struct ppp_file *pf = file->private_data;
466         struct sk_buff *skb;
467         ssize_t ret;
468
469         if (!pf)
470                 return -ENXIO;
471         ret = -ENOMEM;
472         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
473         if (!skb)
474                 goto out;
475         skb_reserve(skb, pf->hdrlen);
476         ret = -EFAULT;
477         if (copy_from_user(skb_put(skb, count), buf, count)) {
478                 kfree_skb(skb);
479                 goto out;
480         }
481
482         skb_queue_tail(&pf->xq, skb);
483
484         switch (pf->kind) {
485         case INTERFACE:
486                 ppp_xmit_process(PF_TO_PPP(pf));
487                 break;
488         case CHANNEL:
489                 ppp_channel_push(PF_TO_CHANNEL(pf));
490                 break;
491         }
492
493         ret = count;
494
495  out:
496         return ret;
497 }
498
499 /* No kernel lock - fine */
500 static unsigned int ppp_poll(struct file *file, poll_table *wait)
501 {
502         struct ppp_file *pf = file->private_data;
503         unsigned int mask;
504
505         if (!pf)
506                 return 0;
507         poll_wait(file, &pf->rwait, wait);
508         mask = POLLOUT | POLLWRNORM;
509         if (skb_peek(&pf->rq))
510                 mask |= POLLIN | POLLRDNORM;
511         if (pf->dead)
512                 mask |= POLLHUP;
513         else if (pf->kind == INTERFACE) {
514                 /* see comment in ppp_read */
515                 struct ppp *ppp = PF_TO_PPP(pf);
516                 if (ppp->n_channels == 0 &&
517                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
518                         mask |= POLLIN | POLLRDNORM;
519         }
520
521         return mask;
522 }
523
524 #ifdef CONFIG_PPP_FILTER
525 static int get_filter(void __user *arg, struct sock_filter **p)
526 {
527         struct sock_fprog uprog;
528         struct sock_filter *code = NULL;
529         int len, err;
530
531         if (copy_from_user(&uprog, arg, sizeof(uprog)))
532                 return -EFAULT;
533
534         if (!uprog.len) {
535                 *p = NULL;
536                 return 0;
537         }
538
539         len = uprog.len * sizeof(struct sock_filter);
540         code = memdup_user(uprog.filter, len);
541         if (IS_ERR(code))
542                 return PTR_ERR(code);
543
544         err = sk_chk_filter(code, uprog.len);
545         if (err) {
546                 kfree(code);
547                 return err;
548         }
549
550         *p = code;
551         return uprog.len;
552 }
553 #endif /* CONFIG_PPP_FILTER */
554
555 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
556 {
557         struct ppp_file *pf = file->private_data;
558         struct ppp *ppp;
559         int err = -EFAULT, val, val2, i;
560         struct ppp_idle idle;
561         struct npioctl npi;
562         int unit, cflags;
563         struct slcompress *vj;
564         void __user *argp = (void __user *)arg;
565         int __user *p = argp;
566
567         if (!pf)
568                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
569                                         pf, file, cmd, arg);
570
571         if (cmd == PPPIOCDETACH) {
572                 /*
573                  * We have to be careful here... if the file descriptor
574                  * has been dup'd, we could have another process in the
575                  * middle of a poll using the same file *, so we had
576                  * better not free the interface data structures -
577                  * instead we fail the ioctl.  Even in this case, we
578                  * shut down the interface if we are the owner of it.
579                  * Actually, we should get rid of PPPIOCDETACH, userland
580                  * (i.e. pppd) could achieve the same effect by closing
581                  * this fd and reopening /dev/ppp.
582                  */
583                 err = -EINVAL;
584                 mutex_lock(&ppp_mutex);
585                 if (pf->kind == INTERFACE) {
586                         ppp = PF_TO_PPP(pf);
587                         if (file == ppp->owner)
588                                 ppp_shutdown_interface(ppp);
589                 }
590                 if (atomic_long_read(&file->f_count) <= 2) {
591                         ppp_release(NULL, file);
592                         err = 0;
593                 } else
594                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
595                                atomic_long_read(&file->f_count));
596                 mutex_unlock(&ppp_mutex);
597                 return err;
598         }
599
600         if (pf->kind == CHANNEL) {
601                 struct channel *pch;
602                 struct ppp_channel *chan;
603
604                 mutex_lock(&ppp_mutex);
605                 pch = PF_TO_CHANNEL(pf);
606
607                 switch (cmd) {
608                 case PPPIOCCONNECT:
609                         if (get_user(unit, p))
610                                 break;
611                         err = ppp_connect_channel(pch, unit);
612                         break;
613
614                 case PPPIOCDISCONN:
615                         err = ppp_disconnect_channel(pch);
616                         break;
617
618                 default:
619                         down_read(&pch->chan_sem);
620                         chan = pch->chan;
621                         err = -ENOTTY;
622                         if (chan && chan->ops->ioctl)
623                                 err = chan->ops->ioctl(chan, cmd, arg);
624                         up_read(&pch->chan_sem);
625                 }
626                 mutex_unlock(&ppp_mutex);
627                 return err;
628         }
629
630         if (pf->kind != INTERFACE) {
631                 /* can't happen */
632                 printk(KERN_ERR "PPP: not interface or channel??\n");
633                 return -EINVAL;
634         }
635
636         mutex_lock(&ppp_mutex);
637         ppp = PF_TO_PPP(pf);
638         switch (cmd) {
639         case PPPIOCSMRU:
640                 if (get_user(val, p))
641                         break;
642                 ppp->mru = val;
643                 err = 0;
644                 break;
645
646         case PPPIOCSFLAGS:
647                 if (get_user(val, p))
648                         break;
649                 ppp_lock(ppp);
650                 cflags = ppp->flags & ~val;
651                 ppp->flags = val & SC_FLAG_BITS;
652                 ppp_unlock(ppp);
653                 if (cflags & SC_CCP_OPEN)
654                         ppp_ccp_closed(ppp);
655                 err = 0;
656                 break;
657
658         case PPPIOCGFLAGS:
659                 val = ppp->flags | ppp->xstate | ppp->rstate;
660                 if (put_user(val, p))
661                         break;
662                 err = 0;
663                 break;
664
665         case PPPIOCSCOMPRESS:
666                 err = ppp_set_compress(ppp, arg);
667                 break;
668
669         case PPPIOCGUNIT:
670                 if (put_user(ppp->file.index, p))
671                         break;
672                 err = 0;
673                 break;
674
675         case PPPIOCSDEBUG:
676                 if (get_user(val, p))
677                         break;
678                 ppp->debug = val;
679                 err = 0;
680                 break;
681
682         case PPPIOCGDEBUG:
683                 if (put_user(ppp->debug, p))
684                         break;
685                 err = 0;
686                 break;
687
688         case PPPIOCGIDLE:
689                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
690                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
691                 if (copy_to_user(argp, &idle, sizeof(idle)))
692                         break;
693                 err = 0;
694                 break;
695
696         case PPPIOCSMAXCID:
697                 if (get_user(val, p))
698                         break;
699                 val2 = 15;
700                 if ((val >> 16) != 0) {
701                         val2 = val >> 16;
702                         val &= 0xffff;
703                 }
704                 vj = slhc_init(val2+1, val+1);
705                 if (!vj) {
706                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
707                         err = -ENOMEM;
708                         break;
709                 }
710                 ppp_lock(ppp);
711                 if (ppp->vj)
712                         slhc_free(ppp->vj);
713                 ppp->vj = vj;
714                 ppp_unlock(ppp);
715                 err = 0;
716                 break;
717
718         case PPPIOCGNPMODE:
719         case PPPIOCSNPMODE:
720                 if (copy_from_user(&npi, argp, sizeof(npi)))
721                         break;
722                 err = proto_to_npindex(npi.protocol);
723                 if (err < 0)
724                         break;
725                 i = err;
726                 if (cmd == PPPIOCGNPMODE) {
727                         err = -EFAULT;
728                         npi.mode = ppp->npmode[i];
729                         if (copy_to_user(argp, &npi, sizeof(npi)))
730                                 break;
731                 } else {
732                         ppp->npmode[i] = npi.mode;
733                         /* we may be able to transmit more packets now (??) */
734                         netif_wake_queue(ppp->dev);
735                 }
736                 err = 0;
737                 break;
738
739 #ifdef CONFIG_PPP_FILTER
740         case PPPIOCSPASS:
741         {
742                 struct sock_filter *code;
743                 err = get_filter(argp, &code);
744                 if (err >= 0) {
745                         ppp_lock(ppp);
746                         kfree(ppp->pass_filter);
747                         ppp->pass_filter = code;
748                         ppp->pass_len = err;
749                         ppp_unlock(ppp);
750                         err = 0;
751                 }
752                 break;
753         }
754         case PPPIOCSACTIVE:
755         {
756                 struct sock_filter *code;
757                 err = get_filter(argp, &code);
758                 if (err >= 0) {
759                         ppp_lock(ppp);
760                         kfree(ppp->active_filter);
761                         ppp->active_filter = code;
762                         ppp->active_len = err;
763                         ppp_unlock(ppp);
764                         err = 0;
765                 }
766                 break;
767         }
768 #endif /* CONFIG_PPP_FILTER */
769
770 #ifdef CONFIG_PPP_MULTILINK
771         case PPPIOCSMRRU:
772                 if (get_user(val, p))
773                         break;
774                 ppp_recv_lock(ppp);
775                 ppp->mrru = val;
776                 ppp_recv_unlock(ppp);
777                 err = 0;
778                 break;
779 #endif /* CONFIG_PPP_MULTILINK */
780
781         default:
782                 err = -ENOTTY;
783         }
784         mutex_unlock(&ppp_mutex);
785         return err;
786 }
787
788 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
789                         struct file *file, unsigned int cmd, unsigned long arg)
790 {
791         int unit, err = -EFAULT;
792         struct ppp *ppp;
793         struct channel *chan;
794         struct ppp_net *pn;
795         int __user *p = (int __user *)arg;
796
797         mutex_lock(&ppp_mutex);
798         switch (cmd) {
799         case PPPIOCNEWUNIT:
800                 /* Create a new ppp unit */
801                 if (get_user(unit, p))
802                         break;
803                 ppp = ppp_create_interface(net, unit, &err);
804                 if (!ppp)
805                         break;
806                 file->private_data = &ppp->file;
807                 ppp->owner = file;
808                 err = -EFAULT;
809                 if (put_user(ppp->file.index, p))
810                         break;
811                 err = 0;
812                 break;
813
814         case PPPIOCATTACH:
815                 /* Attach to an existing ppp unit */
816                 if (get_user(unit, p))
817                         break;
818                 err = -ENXIO;
819                 pn = ppp_pernet(net);
820                 mutex_lock(&pn->all_ppp_mutex);
821                 ppp = ppp_find_unit(pn, unit);
822                 if (ppp) {
823                         atomic_inc(&ppp->file.refcnt);
824                         file->private_data = &ppp->file;
825                         err = 0;
826                 }
827                 mutex_unlock(&pn->all_ppp_mutex);
828                 break;
829
830         case PPPIOCATTCHAN:
831                 if (get_user(unit, p))
832                         break;
833                 err = -ENXIO;
834                 pn = ppp_pernet(net);
835                 spin_lock_bh(&pn->all_channels_lock);
836                 chan = ppp_find_channel(pn, unit);
837                 if (chan) {
838                         atomic_inc(&chan->file.refcnt);
839                         file->private_data = &chan->file;
840                         err = 0;
841                 }
842                 spin_unlock_bh(&pn->all_channels_lock);
843                 break;
844
845         default:
846                 err = -ENOTTY;
847         }
848         mutex_unlock(&ppp_mutex);
849         return err;
850 }
851
852 static const struct file_operations ppp_device_fops = {
853         .owner          = THIS_MODULE,
854         .read           = ppp_read,
855         .write          = ppp_write,
856         .poll           = ppp_poll,
857         .unlocked_ioctl = ppp_ioctl,
858         .open           = ppp_open,
859         .release        = ppp_release,
860         .llseek         = noop_llseek,
861 };
862
863 static __net_init int ppp_init_net(struct net *net)
864 {
865         struct ppp_net *pn = net_generic(net, ppp_net_id);
866
867         idr_init(&pn->units_idr);
868         mutex_init(&pn->all_ppp_mutex);
869
870         INIT_LIST_HEAD(&pn->all_channels);
871         INIT_LIST_HEAD(&pn->new_channels);
872
873         spin_lock_init(&pn->all_channels_lock);
874
875         return 0;
876 }
877
878 static __net_exit void ppp_exit_net(struct net *net)
879 {
880         struct ppp_net *pn = net_generic(net, ppp_net_id);
881
882         idr_destroy(&pn->units_idr);
883 }
884
885 static struct pernet_operations ppp_net_ops = {
886         .init = ppp_init_net,
887         .exit = ppp_exit_net,
888         .id   = &ppp_net_id,
889         .size = sizeof(struct ppp_net),
890 };
891
892 #define PPP_MAJOR       108
893
894 /* Called at boot time if ppp is compiled into the kernel,
895    or at module load time (from init_module) if compiled as a module. */
896 static int __init ppp_init(void)
897 {
898         int err;
899
900         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
901
902         err = register_pernet_device(&ppp_net_ops);
903         if (err) {
904                 printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
905                 goto out;
906         }
907
908         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
909         if (err) {
910                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
911                 goto out_net;
912         }
913
914         ppp_class = class_create(THIS_MODULE, "ppp");
915         if (IS_ERR(ppp_class)) {
916                 err = PTR_ERR(ppp_class);
917                 goto out_chrdev;
918         }
919
920         /* not a big deal if we fail here :-) */
921         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
922
923         return 0;
924
925 out_chrdev:
926         unregister_chrdev(PPP_MAJOR, "ppp");
927 out_net:
928         unregister_pernet_device(&ppp_net_ops);
929 out:
930         return err;
931 }
932
933 /*
934  * Network interface unit routines.
935  */
936 static netdev_tx_t
937 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
938 {
939         struct ppp *ppp = netdev_priv(dev);
940         int npi, proto;
941         unsigned char *pp;
942
943         npi = ethertype_to_npindex(ntohs(skb->protocol));
944         if (npi < 0)
945                 goto outf;
946
947         /* Drop, accept or reject the packet */
948         switch (ppp->npmode[npi]) {
949         case NPMODE_PASS:
950                 break;
951         case NPMODE_QUEUE:
952                 /* it would be nice to have a way to tell the network
953                    system to queue this one up for later. */
954                 goto outf;
955         case NPMODE_DROP:
956         case NPMODE_ERROR:
957                 goto outf;
958         }
959
960         /* Put the 2-byte PPP protocol number on the front,
961            making sure there is room for the address and control fields. */
962         if (skb_cow_head(skb, PPP_HDRLEN))
963                 goto outf;
964
965         pp = skb_push(skb, 2);
966         proto = npindex_to_proto[npi];
967         pp[0] = proto >> 8;
968         pp[1] = proto;
969
970         netif_stop_queue(dev);
971         skb_queue_tail(&ppp->file.xq, skb);
972         ppp_xmit_process(ppp);
973         return NETDEV_TX_OK;
974
975  outf:
976         kfree_skb(skb);
977         ++dev->stats.tx_dropped;
978         return NETDEV_TX_OK;
979 }
980
981 static int
982 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
983 {
984         struct ppp *ppp = netdev_priv(dev);
985         int err = -EFAULT;
986         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
987         struct ppp_stats stats;
988         struct ppp_comp_stats cstats;
989         char *vers;
990
991         switch (cmd) {
992         case SIOCGPPPSTATS:
993                 ppp_get_stats(ppp, &stats);
994                 if (copy_to_user(addr, &stats, sizeof(stats)))
995                         break;
996                 err = 0;
997                 break;
998
999         case SIOCGPPPCSTATS:
1000                 memset(&cstats, 0, sizeof(cstats));
1001                 if (ppp->xc_state)
1002                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1003                 if (ppp->rc_state)
1004                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1005                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1006                         break;
1007                 err = 0;
1008                 break;
1009
1010         case SIOCGPPPVER:
1011                 vers = PPP_VERSION;
1012                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1013                         break;
1014                 err = 0;
1015                 break;
1016
1017         default:
1018                 err = -EINVAL;
1019         }
1020
1021         return err;
1022 }
1023
1024 static const struct net_device_ops ppp_netdev_ops = {
1025         .ndo_start_xmit = ppp_start_xmit,
1026         .ndo_do_ioctl   = ppp_net_ioctl,
1027 };
1028
1029 static void ppp_setup(struct net_device *dev)
1030 {
1031         dev->netdev_ops = &ppp_netdev_ops;
1032         dev->hard_header_len = PPP_HDRLEN;
1033         dev->mtu = PPP_MTU;
1034         dev->addr_len = 0;
1035         dev->tx_queue_len = 3;
1036         dev->type = ARPHRD_PPP;
1037         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1038         dev->features |= NETIF_F_NETNS_LOCAL;
1039         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1040 }
1041
1042 /*
1043  * Transmit-side routines.
1044  */
1045
1046 /*
1047  * Called to do any work queued up on the transmit side
1048  * that can now be done.
1049  */
1050 static void
1051 ppp_xmit_process(struct ppp *ppp)
1052 {
1053         struct sk_buff *skb;
1054
1055         ppp_xmit_lock(ppp);
1056         if (!ppp->closing) {
1057                 ppp_push(ppp);
1058                 while (!ppp->xmit_pending &&
1059                        (skb = skb_dequeue(&ppp->file.xq)))
1060                         ppp_send_frame(ppp, skb);
1061                 /* If there's no work left to do, tell the core net
1062                    code that we can accept some more. */
1063                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1064                         netif_wake_queue(ppp->dev);
1065         }
1066         ppp_xmit_unlock(ppp);
1067 }
1068
1069 static inline struct sk_buff *
1070 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1071 {
1072         struct sk_buff *new_skb;
1073         int len;
1074         int new_skb_size = ppp->dev->mtu +
1075                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1076         int compressor_skb_size = ppp->dev->mtu +
1077                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1078         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1079         if (!new_skb) {
1080                 if (net_ratelimit())
1081                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1082                 return NULL;
1083         }
1084         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1085                 skb_reserve(new_skb,
1086                             ppp->dev->hard_header_len - PPP_HDRLEN);
1087
1088         /* compressor still expects A/C bytes in hdr */
1089         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1090                                    new_skb->data, skb->len + 2,
1091                                    compressor_skb_size);
1092         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1093                 kfree_skb(skb);
1094                 skb = new_skb;
1095                 skb_put(skb, len);
1096                 skb_pull(skb, 2);       /* pull off A/C bytes */
1097         } else if (len == 0) {
1098                 /* didn't compress, or CCP not up yet */
1099                 kfree_skb(new_skb);
1100                 new_skb = skb;
1101         } else {
1102                 /*
1103                  * (len < 0)
1104                  * MPPE requires that we do not send unencrypted
1105                  * frames.  The compressor will return -1 if we
1106                  * should drop the frame.  We cannot simply test
1107                  * the compress_proto because MPPE and MPPC share
1108                  * the same number.
1109                  */
1110                 if (net_ratelimit())
1111                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1112                 kfree_skb(skb);
1113                 kfree_skb(new_skb);
1114                 new_skb = NULL;
1115         }
1116         return new_skb;
1117 }
1118
1119 /*
1120  * Compress and send a frame.
1121  * The caller should have locked the xmit path,
1122  * and xmit_pending should be 0.
1123  */
1124 static void
1125 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1126 {
1127         int proto = PPP_PROTO(skb);
1128         struct sk_buff *new_skb;
1129         int len;
1130         unsigned char *cp;
1131
1132         if (proto < 0x8000) {
1133 #ifdef CONFIG_PPP_FILTER
1134                 /* check if we should pass this packet */
1135                 /* the filter instructions are constructed assuming
1136                    a four-byte PPP header on each packet */
1137                 *skb_push(skb, 2) = 1;
1138                 if (ppp->pass_filter &&
1139                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1140                         if (ppp->debug & 1)
1141                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1142                         kfree_skb(skb);
1143                         return;
1144                 }
1145                 /* if this packet passes the active filter, record the time */
1146                 if (!(ppp->active_filter &&
1147                       sk_run_filter(skb, ppp->active_filter) == 0))
1148                         ppp->last_xmit = jiffies;
1149                 skb_pull(skb, 2);
1150 #else
1151                 /* for data packets, record the time */
1152                 ppp->last_xmit = jiffies;
1153 #endif /* CONFIG_PPP_FILTER */
1154         }
1155
1156         ++ppp->dev->stats.tx_packets;
1157         ppp->dev->stats.tx_bytes += skb->len - 2;
1158
1159         switch (proto) {
1160         case PPP_IP:
1161                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1162                         break;
1163                 /* try to do VJ TCP header compression */
1164                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1165                                     GFP_ATOMIC);
1166                 if (!new_skb) {
1167                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1168                         goto drop;
1169                 }
1170                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1171                 cp = skb->data + 2;
1172                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1173                                     new_skb->data + 2, &cp,
1174                                     !(ppp->flags & SC_NO_TCP_CCID));
1175                 if (cp == skb->data + 2) {
1176                         /* didn't compress */
1177                         kfree_skb(new_skb);
1178                 } else {
1179                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1180                                 proto = PPP_VJC_COMP;
1181                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1182                         } else {
1183                                 proto = PPP_VJC_UNCOMP;
1184                                 cp[0] = skb->data[2];
1185                         }
1186                         kfree_skb(skb);
1187                         skb = new_skb;
1188                         cp = skb_put(skb, len + 2);
1189                         cp[0] = 0;
1190                         cp[1] = proto;
1191                 }
1192                 break;
1193
1194         case PPP_CCP:
1195                 /* peek at outbound CCP frames */
1196                 ppp_ccp_peek(ppp, skb, 0);
1197                 break;
1198         }
1199
1200         /* try to do packet compression */
1201         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1202             proto != PPP_LCP && proto != PPP_CCP) {
1203                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1204                         if (net_ratelimit())
1205                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1206                         goto drop;
1207                 }
1208                 skb = pad_compress_skb(ppp, skb);
1209                 if (!skb)
1210                         goto drop;
1211         }
1212
1213         /*
1214          * If we are waiting for traffic (demand dialling),
1215          * queue it up for pppd to receive.
1216          */
1217         if (ppp->flags & SC_LOOP_TRAFFIC) {
1218                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1219                         goto drop;
1220                 skb_queue_tail(&ppp->file.rq, skb);
1221                 wake_up_interruptible(&ppp->file.rwait);
1222                 return;
1223         }
1224
1225         ppp->xmit_pending = skb;
1226         ppp_push(ppp);
1227         return;
1228
1229  drop:
1230         kfree_skb(skb);
1231         ++ppp->dev->stats.tx_errors;
1232 }
1233
1234 /*
1235  * Try to send the frame in xmit_pending.
1236  * The caller should have the xmit path locked.
1237  */
1238 static void
1239 ppp_push(struct ppp *ppp)
1240 {
1241         struct list_head *list;
1242         struct channel *pch;
1243         struct sk_buff *skb = ppp->xmit_pending;
1244
1245         if (!skb)
1246                 return;
1247
1248         list = &ppp->channels;
1249         if (list_empty(list)) {
1250                 /* nowhere to send the packet, just drop it */
1251                 ppp->xmit_pending = NULL;
1252                 kfree_skb(skb);
1253                 return;
1254         }
1255
1256         if ((ppp->flags & SC_MULTILINK) == 0) {
1257                 /* not doing multilink: send it down the first channel */
1258                 list = list->next;
1259                 pch = list_entry(list, struct channel, clist);
1260
1261                 spin_lock_bh(&pch->downl);
1262                 if (pch->chan) {
1263                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1264                                 ppp->xmit_pending = NULL;
1265                 } else {
1266                         /* channel got unregistered */
1267                         kfree_skb(skb);
1268                         ppp->xmit_pending = NULL;
1269                 }
1270                 spin_unlock_bh(&pch->downl);
1271                 return;
1272         }
1273
1274 #ifdef CONFIG_PPP_MULTILINK
1275         /* Multilink: fragment the packet over as many links
1276            as can take the packet at the moment. */
1277         if (!ppp_mp_explode(ppp, skb))
1278                 return;
1279 #endif /* CONFIG_PPP_MULTILINK */
1280
1281         ppp->xmit_pending = NULL;
1282         kfree_skb(skb);
1283 }
1284
1285 #ifdef CONFIG_PPP_MULTILINK
1286 static bool mp_protocol_compress __read_mostly = true;
1287 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1288 MODULE_PARM_DESC(mp_protocol_compress,
1289                  "compress protocol id in multilink fragments");
1290
1291 /*
1292  * Divide a packet to be transmitted into fragments and
1293  * send them out the individual links.
1294  */
1295 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1296 {
1297         int len, totlen;
1298         int i, bits, hdrlen, mtu;
1299         int flen;
1300         int navail, nfree, nzero;
1301         int nbigger;
1302         int totspeed;
1303         int totfree;
1304         unsigned char *p, *q;
1305         struct list_head *list;
1306         struct channel *pch;
1307         struct sk_buff *frag;
1308         struct ppp_channel *chan;
1309
1310         totspeed = 0; /*total bitrate of the bundle*/
1311         nfree = 0; /* # channels which have no packet already queued */
1312         navail = 0; /* total # of usable channels (not deregistered) */
1313         nzero = 0; /* number of channels with zero speed associated*/
1314         totfree = 0; /*total # of channels available and
1315                                   *having no queued packets before
1316                                   *starting the fragmentation*/
1317
1318         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1319         i = 0;
1320         list_for_each_entry(pch, &ppp->channels, clist) {
1321                 if (pch->chan) {
1322                         pch->avail = 1;
1323                         navail++;
1324                         pch->speed = pch->chan->speed;
1325                 } else {
1326                         pch->avail = 0;
1327                 }
1328                 if (pch->avail) {
1329                         if (skb_queue_empty(&pch->file.xq) ||
1330                                 !pch->had_frag) {
1331                                         if (pch->speed == 0)
1332                                                 nzero++;
1333                                         else
1334                                                 totspeed += pch->speed;
1335
1336                                         pch->avail = 2;
1337                                         ++nfree;
1338                                         ++totfree;
1339                                 }
1340                         if (!pch->had_frag && i < ppp->nxchan)
1341                                 ppp->nxchan = i;
1342                 }
1343                 ++i;
1344         }
1345         /*
1346          * Don't start sending this packet unless at least half of
1347          * the channels are free.  This gives much better TCP
1348          * performance if we have a lot of channels.
1349          */
1350         if (nfree == 0 || nfree < navail / 2)
1351                 return 0; /* can't take now, leave it in xmit_pending */
1352
1353         /* Do protocol field compression */
1354         p = skb->data;
1355         len = skb->len;
1356         if (*p == 0 && mp_protocol_compress) {
1357                 ++p;
1358                 --len;
1359         }
1360
1361         totlen = len;
1362         nbigger = len % nfree;
1363
1364         /* skip to the channel after the one we last used
1365            and start at that one */
1366         list = &ppp->channels;
1367         for (i = 0; i < ppp->nxchan; ++i) {
1368                 list = list->next;
1369                 if (list == &ppp->channels) {
1370                         i = 0;
1371                         break;
1372                 }
1373         }
1374
1375         /* create a fragment for each channel */
1376         bits = B;
1377         while (len > 0) {
1378                 list = list->next;
1379                 if (list == &ppp->channels) {
1380                         i = 0;
1381                         continue;
1382                 }
1383                 pch = list_entry(list, struct channel, clist);
1384                 ++i;
1385                 if (!pch->avail)
1386                         continue;
1387
1388                 /*
1389                  * Skip this channel if it has a fragment pending already and
1390                  * we haven't given a fragment to all of the free channels.
1391                  */
1392                 if (pch->avail == 1) {
1393                         if (nfree > 0)
1394                                 continue;
1395                 } else {
1396                         pch->avail = 1;
1397                 }
1398
1399                 /* check the channel's mtu and whether it is still attached. */
1400                 spin_lock_bh(&pch->downl);
1401                 if (pch->chan == NULL) {
1402                         /* can't use this channel, it's being deregistered */
1403                         if (pch->speed == 0)
1404                                 nzero--;
1405                         else
1406                                 totspeed -= pch->speed;
1407
1408                         spin_unlock_bh(&pch->downl);
1409                         pch->avail = 0;
1410                         totlen = len;
1411                         totfree--;
1412                         nfree--;
1413                         if (--navail == 0)
1414                                 break;
1415                         continue;
1416                 }
1417
1418                 /*
1419                 *if the channel speed is not set divide
1420                 *the packet evenly among the free channels;
1421                 *otherwise divide it according to the speed
1422                 *of the channel we are going to transmit on
1423                 */
1424                 flen = len;
1425                 if (nfree > 0) {
1426                         if (pch->speed == 0) {
1427                                 flen = len/nfree;
1428                                 if (nbigger > 0) {
1429                                         flen++;
1430                                         nbigger--;
1431                                 }
1432                         } else {
1433                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1434                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1435                                 if (nbigger > 0) {
1436                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1437                                         nbigger -= ((totfree - nzero)*pch->speed)/
1438                                                         totspeed;
1439                                 }
1440                         }
1441                         nfree--;
1442                 }
1443
1444                 /*
1445                  *check if we are on the last channel or
1446                  *we exceded the lenght of the data to
1447                  *fragment
1448                  */
1449                 if ((nfree <= 0) || (flen > len))
1450                         flen = len;
1451                 /*
1452                  *it is not worth to tx on slow channels:
1453                  *in that case from the resulting flen according to the
1454                  *above formula will be equal or less than zero.
1455                  *Skip the channel in this case
1456                  */
1457                 if (flen <= 0) {
1458                         pch->avail = 2;
1459                         spin_unlock_bh(&pch->downl);
1460                         continue;
1461                 }
1462
1463                 mtu = pch->chan->mtu - hdrlen;
1464                 if (mtu < 4)
1465                         mtu = 4;
1466                 if (flen > mtu)
1467                         flen = mtu;
1468                 if (flen == len)
1469                         bits |= E;
1470                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1471                 if (!frag)
1472                         goto noskb;
1473                 q = skb_put(frag, flen + hdrlen);
1474
1475                 /* make the MP header */
1476                 q[0] = PPP_MP >> 8;
1477                 q[1] = PPP_MP;
1478                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1479                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1480                         q[3] = ppp->nxseq;
1481                 } else {
1482                         q[2] = bits;
1483                         q[3] = ppp->nxseq >> 16;
1484                         q[4] = ppp->nxseq >> 8;
1485                         q[5] = ppp->nxseq;
1486                 }
1487
1488                 memcpy(q + hdrlen, p, flen);
1489
1490                 /* try to send it down the channel */
1491                 chan = pch->chan;
1492                 if (!skb_queue_empty(&pch->file.xq) ||
1493                         !chan->ops->start_xmit(chan, frag))
1494                         skb_queue_tail(&pch->file.xq, frag);
1495                 pch->had_frag = 1;
1496                 p += flen;
1497                 len -= flen;
1498                 ++ppp->nxseq;
1499                 bits = 0;
1500                 spin_unlock_bh(&pch->downl);
1501         }
1502         ppp->nxchan = i;
1503
1504         return 1;
1505
1506  noskb:
1507         spin_unlock_bh(&pch->downl);
1508         if (ppp->debug & 1)
1509                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1510         ++ppp->dev->stats.tx_errors;
1511         ++ppp->nxseq;
1512         return 1;       /* abandon the frame */
1513 }
1514 #endif /* CONFIG_PPP_MULTILINK */
1515
1516 /*
1517  * Try to send data out on a channel.
1518  */
1519 static void
1520 ppp_channel_push(struct channel *pch)
1521 {
1522         struct sk_buff *skb;
1523         struct ppp *ppp;
1524
1525         spin_lock_bh(&pch->downl);
1526         if (pch->chan) {
1527                 while (!skb_queue_empty(&pch->file.xq)) {
1528                         skb = skb_dequeue(&pch->file.xq);
1529                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1530                                 /* put the packet back and try again later */
1531                                 skb_queue_head(&pch->file.xq, skb);
1532                                 break;
1533                         }
1534                 }
1535         } else {
1536                 /* channel got deregistered */
1537                 skb_queue_purge(&pch->file.xq);
1538         }
1539         spin_unlock_bh(&pch->downl);
1540         /* see if there is anything from the attached unit to be sent */
1541         if (skb_queue_empty(&pch->file.xq)) {
1542                 read_lock_bh(&pch->upl);
1543                 ppp = pch->ppp;
1544                 if (ppp)
1545                         ppp_xmit_process(ppp);
1546                 read_unlock_bh(&pch->upl);
1547         }
1548 }
1549
1550 /*
1551  * Receive-side routines.
1552  */
1553
1554 struct ppp_mp_skb_parm {
1555         u32             sequence;
1556         u8              BEbits;
1557 };
1558 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1559
1560 static inline void
1561 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1562 {
1563         ppp_recv_lock(ppp);
1564         if (!ppp->closing)
1565                 ppp_receive_frame(ppp, skb, pch);
1566         else
1567                 kfree_skb(skb);
1568         ppp_recv_unlock(ppp);
1569 }
1570
1571 void
1572 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1573 {
1574         struct channel *pch = chan->ppp;
1575         int proto;
1576
1577         if (!pch) {
1578                 kfree_skb(skb);
1579                 return;
1580         }
1581
1582         read_lock_bh(&pch->upl);
1583         if (!pskb_may_pull(skb, 2)) {
1584                 kfree_skb(skb);
1585                 if (pch->ppp) {
1586                         ++pch->ppp->dev->stats.rx_length_errors;
1587                         ppp_receive_error(pch->ppp);
1588                 }
1589                 goto done;
1590         }
1591
1592         proto = PPP_PROTO(skb);
1593         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1594                 /* put it on the channel queue */
1595                 skb_queue_tail(&pch->file.rq, skb);
1596                 /* drop old frames if queue too long */
1597                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1598                        (skb = skb_dequeue(&pch->file.rq)))
1599                         kfree_skb(skb);
1600                 wake_up_interruptible(&pch->file.rwait);
1601         } else {
1602                 ppp_do_recv(pch->ppp, skb, pch);
1603         }
1604
1605 done:
1606         read_unlock_bh(&pch->upl);
1607 }
1608
1609 /* Put a 0-length skb in the receive queue as an error indication */
1610 void
1611 ppp_input_error(struct ppp_channel *chan, int code)
1612 {
1613         struct channel *pch = chan->ppp;
1614         struct sk_buff *skb;
1615
1616         if (!pch)
1617                 return;
1618
1619         read_lock_bh(&pch->upl);
1620         if (pch->ppp) {
1621                 skb = alloc_skb(0, GFP_ATOMIC);
1622                 if (skb) {
1623                         skb->len = 0;           /* probably unnecessary */
1624                         skb->cb[0] = code;
1625                         ppp_do_recv(pch->ppp, skb, pch);
1626                 }
1627         }
1628         read_unlock_bh(&pch->upl);
1629 }
1630
1631 /*
1632  * We come in here to process a received frame.
1633  * The receive side of the ppp unit is locked.
1634  */
1635 static void
1636 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1637 {
1638         /* note: a 0-length skb is used as an error indication */
1639         if (skb->len > 0) {
1640 #ifdef CONFIG_PPP_MULTILINK
1641                 /* XXX do channel-level decompression here */
1642                 if (PPP_PROTO(skb) == PPP_MP)
1643                         ppp_receive_mp_frame(ppp, skb, pch);
1644                 else
1645 #endif /* CONFIG_PPP_MULTILINK */
1646                         ppp_receive_nonmp_frame(ppp, skb);
1647         } else {
1648                 kfree_skb(skb);
1649                 ppp_receive_error(ppp);
1650         }
1651 }
1652
1653 static void
1654 ppp_receive_error(struct ppp *ppp)
1655 {
1656         ++ppp->dev->stats.rx_errors;
1657         if (ppp->vj)
1658                 slhc_toss(ppp->vj);
1659 }
1660
1661 static void
1662 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1663 {
1664         struct sk_buff *ns;
1665         int proto, len, npi;
1666
1667         /*
1668          * Decompress the frame, if compressed.
1669          * Note that some decompressors need to see uncompressed frames
1670          * that come in as well as compressed frames.
1671          */
1672         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1673             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1674                 skb = ppp_decompress_frame(ppp, skb);
1675
1676         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1677                 goto err;
1678
1679         proto = PPP_PROTO(skb);
1680         switch (proto) {
1681         case PPP_VJC_COMP:
1682                 /* decompress VJ compressed packets */
1683                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1684                         goto err;
1685
1686                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1687                         /* copy to a new sk_buff with more tailroom */
1688                         ns = dev_alloc_skb(skb->len + 128);
1689                         if (!ns) {
1690                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1691                                 goto err;
1692                         }
1693                         skb_reserve(ns, 2);
1694                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1695                         kfree_skb(skb);
1696                         skb = ns;
1697                 }
1698                 else
1699                         skb->ip_summed = CHECKSUM_NONE;
1700
1701                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1702                 if (len <= 0) {
1703                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1704                         goto err;
1705                 }
1706                 len += 2;
1707                 if (len > skb->len)
1708                         skb_put(skb, len - skb->len);
1709                 else if (len < skb->len)
1710                         skb_trim(skb, len);
1711                 proto = PPP_IP;
1712                 break;
1713
1714         case PPP_VJC_UNCOMP:
1715                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1716                         goto err;
1717
1718                 /* Until we fix the decompressor need to make sure
1719                  * data portion is linear.
1720                  */
1721                 if (!pskb_may_pull(skb, skb->len))
1722                         goto err;
1723
1724                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1725                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1726                         goto err;
1727                 }
1728                 proto = PPP_IP;
1729                 break;
1730
1731         case PPP_CCP:
1732                 ppp_ccp_peek(ppp, skb, 1);
1733                 break;
1734         }
1735
1736         ++ppp->dev->stats.rx_packets;
1737         ppp->dev->stats.rx_bytes += skb->len - 2;
1738
1739         npi = proto_to_npindex(proto);
1740         if (npi < 0) {
1741                 /* control or unknown frame - pass it to pppd */
1742                 skb_queue_tail(&ppp->file.rq, skb);
1743                 /* limit queue length by dropping old frames */
1744                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1745                        (skb = skb_dequeue(&ppp->file.rq)))
1746                         kfree_skb(skb);
1747                 /* wake up any process polling or blocking on read */
1748                 wake_up_interruptible(&ppp->file.rwait);
1749
1750         } else {
1751                 /* network protocol frame - give it to the kernel */
1752
1753 #ifdef CONFIG_PPP_FILTER
1754                 /* check if the packet passes the pass and active filters */
1755                 /* the filter instructions are constructed assuming
1756                    a four-byte PPP header on each packet */
1757                 if (ppp->pass_filter || ppp->active_filter) {
1758                         if (skb_cloned(skb) &&
1759                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1760                                 goto err;
1761
1762                         *skb_push(skb, 2) = 0;
1763                         if (ppp->pass_filter &&
1764                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1765                                 if (ppp->debug & 1)
1766                                         printk(KERN_DEBUG "PPP: inbound frame "
1767                                                "not passed\n");
1768                                 kfree_skb(skb);
1769                                 return;
1770                         }
1771                         if (!(ppp->active_filter &&
1772                               sk_run_filter(skb, ppp->active_filter) == 0))
1773                                 ppp->last_recv = jiffies;
1774                         __skb_pull(skb, 2);
1775                 } else
1776 #endif /* CONFIG_PPP_FILTER */
1777                         ppp->last_recv = jiffies;
1778
1779                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1780                     ppp->npmode[npi] != NPMODE_PASS) {
1781                         kfree_skb(skb);
1782                 } else {
1783                         /* chop off protocol */
1784                         skb_pull_rcsum(skb, 2);
1785                         skb->dev = ppp->dev;
1786                         skb->protocol = htons(npindex_to_ethertype[npi]);
1787                         skb_reset_mac_header(skb);
1788                         netif_rx(skb);
1789                 }
1790         }
1791         return;
1792
1793  err:
1794         kfree_skb(skb);
1795         ppp_receive_error(ppp);
1796 }
1797
1798 static struct sk_buff *
1799 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1800 {
1801         int proto = PPP_PROTO(skb);
1802         struct sk_buff *ns;
1803         int len;
1804
1805         /* Until we fix all the decompressor's need to make sure
1806          * data portion is linear.
1807          */
1808         if (!pskb_may_pull(skb, skb->len))
1809                 goto err;
1810
1811         if (proto == PPP_COMP) {
1812                 int obuff_size;
1813
1814                 switch(ppp->rcomp->compress_proto) {
1815                 case CI_MPPE:
1816                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1817                         break;
1818                 default:
1819                         obuff_size = ppp->mru + PPP_HDRLEN;
1820                         break;
1821                 }
1822
1823                 ns = dev_alloc_skb(obuff_size);
1824                 if (!ns) {
1825                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1826                         goto err;
1827                 }
1828                 /* the decompressor still expects the A/C bytes in the hdr */
1829                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1830                                 skb->len + 2, ns->data, obuff_size);
1831                 if (len < 0) {
1832                         /* Pass the compressed frame to pppd as an
1833                            error indication. */
1834                         if (len == DECOMP_FATALERROR)
1835                                 ppp->rstate |= SC_DC_FERROR;
1836                         kfree_skb(ns);
1837                         goto err;
1838                 }
1839
1840                 kfree_skb(skb);
1841                 skb = ns;
1842                 skb_put(skb, len);
1843                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1844
1845         } else {
1846                 /* Uncompressed frame - pass to decompressor so it
1847                    can update its dictionary if necessary. */
1848                 if (ppp->rcomp->incomp)
1849                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1850                                            skb->len + 2);
1851         }
1852
1853         return skb;
1854
1855  err:
1856         ppp->rstate |= SC_DC_ERROR;
1857         ppp_receive_error(ppp);
1858         return skb;
1859 }
1860
1861 #ifdef CONFIG_PPP_MULTILINK
1862 /*
1863  * Receive a multilink frame.
1864  * We put it on the reconstruction queue and then pull off
1865  * as many completed frames as we can.
1866  */
1867 static void
1868 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1869 {
1870         u32 mask, seq;
1871         struct channel *ch;
1872         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1873
1874         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1875                 goto err;               /* no good, throw it away */
1876
1877         /* Decode sequence number and begin/end bits */
1878         if (ppp->flags & SC_MP_SHORTSEQ) {
1879                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1880                 mask = 0xfff;
1881         } else {
1882                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1883                 mask = 0xffffff;
1884         }
1885         PPP_MP_CB(skb)->BEbits = skb->data[2];
1886         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1887
1888         /*
1889          * Do protocol ID decompression on the first fragment of each packet.
1890          */
1891         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1892                 *skb_push(skb, 1) = 0;
1893
1894         /*
1895          * Expand sequence number to 32 bits, making it as close
1896          * as possible to ppp->minseq.
1897          */
1898         seq |= ppp->minseq & ~mask;
1899         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1900                 seq += mask + 1;
1901         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1902                 seq -= mask + 1;        /* should never happen */
1903         PPP_MP_CB(skb)->sequence = seq;
1904         pch->lastseq = seq;
1905
1906         /*
1907          * If this packet comes before the next one we were expecting,
1908          * drop it.
1909          */
1910         if (seq_before(seq, ppp->nextseq)) {
1911                 kfree_skb(skb);
1912                 ++ppp->dev->stats.rx_dropped;
1913                 ppp_receive_error(ppp);
1914                 return;
1915         }
1916
1917         /*
1918          * Reevaluate minseq, the minimum over all channels of the
1919          * last sequence number received on each channel.  Because of
1920          * the increasing sequence number rule, we know that any fragment
1921          * before `minseq' which hasn't arrived is never going to arrive.
1922          * The list of channels can't change because we have the receive
1923          * side of the ppp unit locked.
1924          */
1925         list_for_each_entry(ch, &ppp->channels, clist) {
1926                 if (seq_before(ch->lastseq, seq))
1927                         seq = ch->lastseq;
1928         }
1929         if (seq_before(ppp->minseq, seq))
1930                 ppp->minseq = seq;
1931
1932         /* Put the fragment on the reconstruction queue */
1933         ppp_mp_insert(ppp, skb);
1934
1935         /* If the queue is getting long, don't wait any longer for packets
1936            before the start of the queue. */
1937         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1938                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1939                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1940                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
1941         }
1942
1943         /* Pull completed packets off the queue and receive them. */
1944         while ((skb = ppp_mp_reconstruct(ppp))) {
1945                 if (pskb_may_pull(skb, 2))
1946                         ppp_receive_nonmp_frame(ppp, skb);
1947                 else {
1948                         ++ppp->dev->stats.rx_length_errors;
1949                         kfree_skb(skb);
1950                         ppp_receive_error(ppp);
1951                 }
1952         }
1953
1954         return;
1955
1956  err:
1957         kfree_skb(skb);
1958         ppp_receive_error(ppp);
1959 }
1960
1961 /*
1962  * Insert a fragment on the MP reconstruction queue.
1963  * The queue is ordered by increasing sequence number.
1964  */
1965 static void
1966 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1967 {
1968         struct sk_buff *p;
1969         struct sk_buff_head *list = &ppp->mrq;
1970         u32 seq = PPP_MP_CB(skb)->sequence;
1971
1972         /* N.B. we don't need to lock the list lock because we have the
1973            ppp unit receive-side lock. */
1974         skb_queue_walk(list, p) {
1975                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
1976                         break;
1977         }
1978         __skb_queue_before(list, p, skb);
1979 }
1980
1981 /*
1982  * Reconstruct a packet from the MP fragment queue.
1983  * We go through increasing sequence numbers until we find a
1984  * complete packet, or we get to the sequence number for a fragment
1985  * which hasn't arrived but might still do so.
1986  */
1987 static struct sk_buff *
1988 ppp_mp_reconstruct(struct ppp *ppp)
1989 {
1990         u32 seq = ppp->nextseq;
1991         u32 minseq = ppp->minseq;
1992         struct sk_buff_head *list = &ppp->mrq;
1993         struct sk_buff *p, *next;
1994         struct sk_buff *head, *tail;
1995         struct sk_buff *skb = NULL;
1996         int lost = 0, len = 0;
1997
1998         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1999                 return NULL;
2000         head = list->next;
2001         tail = NULL;
2002         for (p = head; p != (struct sk_buff *) list; p = next) {
2003                 next = p->next;
2004                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2005                         /* this can't happen, anyway ignore the skb */
2006                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
2007                                PPP_MP_CB(p)->sequence, seq);
2008                         head = next;
2009                         continue;
2010                 }
2011                 if (PPP_MP_CB(p)->sequence != seq) {
2012                         /* Fragment `seq' is missing.  If it is after
2013                            minseq, it might arrive later, so stop here. */
2014                         if (seq_after(seq, minseq))
2015                                 break;
2016                         /* Fragment `seq' is lost, keep going. */
2017                         lost = 1;
2018                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2019                                 minseq + 1: PPP_MP_CB(p)->sequence;
2020                         next = p;
2021                         continue;
2022                 }
2023
2024                 /*
2025                  * At this point we know that all the fragments from
2026                  * ppp->nextseq to seq are either present or lost.
2027                  * Also, there are no complete packets in the queue
2028                  * that have no missing fragments and end before this
2029                  * fragment.
2030                  */
2031
2032                 /* B bit set indicates this fragment starts a packet */
2033                 if (PPP_MP_CB(p)->BEbits & B) {
2034                         head = p;
2035                         lost = 0;
2036                         len = 0;
2037                 }
2038
2039                 len += p->len;
2040
2041                 /* Got a complete packet yet? */
2042                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2043                     (PPP_MP_CB(head)->BEbits & B)) {
2044                         if (len > ppp->mrru + 2) {
2045                                 ++ppp->dev->stats.rx_length_errors;
2046                                 printk(KERN_DEBUG "PPP: reconstructed packet"
2047                                        " is too long (%d)\n", len);
2048                         } else if (p == head) {
2049                                 /* fragment is complete packet - reuse skb */
2050                                 tail = p;
2051                                 skb = skb_get(p);
2052                                 break;
2053                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
2054                                 ++ppp->dev->stats.rx_missed_errors;
2055                                 printk(KERN_DEBUG "PPP: no memory for "
2056                                        "reconstructed packet");
2057                         } else {
2058                                 tail = p;
2059                                 break;
2060                         }
2061                         ppp->nextseq = seq + 1;
2062                 }
2063
2064                 /*
2065                  * If this is the ending fragment of a packet,
2066                  * and we haven't found a complete valid packet yet,
2067                  * we can discard up to and including this fragment.
2068                  */
2069                 if (PPP_MP_CB(p)->BEbits & E)
2070                         head = next;
2071
2072                 ++seq;
2073         }
2074
2075         /* If we have a complete packet, copy it all into one skb. */
2076         if (tail != NULL) {
2077                 /* If we have discarded any fragments,
2078                    signal a receive error. */
2079                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2080                         if (ppp->debug & 1)
2081                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
2082                                        ppp->nextseq,
2083                                        PPP_MP_CB(head)->sequence-1);
2084                         ++ppp->dev->stats.rx_dropped;
2085                         ppp_receive_error(ppp);
2086                 }
2087
2088                 if (head != tail)
2089                         /* copy to a single skb */
2090                         for (p = head; p != tail->next; p = p->next)
2091                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
2092                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2093                 head = tail->next;
2094         }
2095
2096         /* Discard all the skbuffs that we have copied the data out of
2097            or that we can't use. */
2098         while ((p = list->next) != head) {
2099                 __skb_unlink(p, list);
2100                 kfree_skb(p);
2101         }
2102
2103         return skb;
2104 }
2105 #endif /* CONFIG_PPP_MULTILINK */
2106
2107 /*
2108  * Channel interface.
2109  */
2110
2111 /* Create a new, unattached ppp channel. */
2112 int ppp_register_channel(struct ppp_channel *chan)
2113 {
2114         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2115 }
2116
2117 /* Create a new, unattached ppp channel for specified net. */
2118 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2119 {
2120         struct channel *pch;
2121         struct ppp_net *pn;
2122
2123         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2124         if (!pch)
2125                 return -ENOMEM;
2126
2127         pn = ppp_pernet(net);
2128
2129         pch->ppp = NULL;
2130         pch->chan = chan;
2131         pch->chan_net = net;
2132         chan->ppp = pch;
2133         init_ppp_file(&pch->file, CHANNEL);
2134         pch->file.hdrlen = chan->hdrlen;
2135 #ifdef CONFIG_PPP_MULTILINK
2136         pch->lastseq = -1;
2137 #endif /* CONFIG_PPP_MULTILINK */
2138         init_rwsem(&pch->chan_sem);
2139         spin_lock_init(&pch->downl);
2140         rwlock_init(&pch->upl);
2141
2142         spin_lock_bh(&pn->all_channels_lock);
2143         pch->file.index = ++pn->last_channel_index;
2144         list_add(&pch->list, &pn->new_channels);
2145         atomic_inc(&channel_count);
2146         spin_unlock_bh(&pn->all_channels_lock);
2147
2148         return 0;
2149 }
2150
2151 /*
2152  * Return the index of a channel.
2153  */
2154 int ppp_channel_index(struct ppp_channel *chan)
2155 {
2156         struct channel *pch = chan->ppp;
2157
2158         if (pch)
2159                 return pch->file.index;
2160         return -1;
2161 }
2162
2163 /*
2164  * Return the PPP unit number to which a channel is connected.
2165  */
2166 int ppp_unit_number(struct ppp_channel *chan)
2167 {
2168         struct channel *pch = chan->ppp;
2169         int unit = -1;
2170
2171         if (pch) {
2172                 read_lock_bh(&pch->upl);
2173                 if (pch->ppp)
2174                         unit = pch->ppp->file.index;
2175                 read_unlock_bh(&pch->upl);
2176         }
2177         return unit;
2178 }
2179
2180 /*
2181  * Return the PPP device interface name of a channel.
2182  */
2183 char *ppp_dev_name(struct ppp_channel *chan)
2184 {
2185         struct channel *pch = chan->ppp;
2186         char *name = NULL;
2187
2188         if (pch) {
2189                 read_lock_bh(&pch->upl);
2190                 if (pch->ppp && pch->ppp->dev)
2191                         name = pch->ppp->dev->name;
2192                 read_unlock_bh(&pch->upl);
2193         }
2194         return name;
2195 }
2196
2197
2198 /*
2199  * Disconnect a channel from the generic layer.
2200  * This must be called in process context.
2201  */
2202 void
2203 ppp_unregister_channel(struct ppp_channel *chan)
2204 {
2205         struct channel *pch = chan->ppp;
2206         struct ppp_net *pn;
2207
2208         if (!pch)
2209                 return;         /* should never happen */
2210
2211         chan->ppp = NULL;
2212
2213         /*
2214          * This ensures that we have returned from any calls into the
2215          * the channel's start_xmit or ioctl routine before we proceed.
2216          */
2217         down_write(&pch->chan_sem);
2218         spin_lock_bh(&pch->downl);
2219         pch->chan = NULL;
2220         spin_unlock_bh(&pch->downl);
2221         up_write(&pch->chan_sem);
2222         ppp_disconnect_channel(pch);
2223
2224         pn = ppp_pernet(pch->chan_net);
2225         spin_lock_bh(&pn->all_channels_lock);
2226         list_del(&pch->list);
2227         spin_unlock_bh(&pn->all_channels_lock);
2228
2229         pch->file.dead = 1;
2230         wake_up_interruptible(&pch->file.rwait);
2231         if (atomic_dec_and_test(&pch->file.refcnt))
2232                 ppp_destroy_channel(pch);
2233 }
2234
2235 /*
2236  * Callback from a channel when it can accept more to transmit.
2237  * This should be called at BH/softirq level, not interrupt level.
2238  */
2239 void
2240 ppp_output_wakeup(struct ppp_channel *chan)
2241 {
2242         struct channel *pch = chan->ppp;
2243
2244         if (!pch)
2245                 return;
2246         ppp_channel_push(pch);
2247 }
2248
2249 /*
2250  * Compression control.
2251  */
2252
2253 /* Process the PPPIOCSCOMPRESS ioctl. */
2254 static int
2255 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2256 {
2257         int err;
2258         struct compressor *cp, *ocomp;
2259         struct ppp_option_data data;
2260         void *state, *ostate;
2261         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2262
2263         err = -EFAULT;
2264         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2265             (data.length <= CCP_MAX_OPTION_LENGTH &&
2266              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2267                 goto out;
2268         err = -EINVAL;
2269         if (data.length > CCP_MAX_OPTION_LENGTH ||
2270             ccp_option[1] < 2 || ccp_option[1] > data.length)
2271                 goto out;
2272
2273         cp = try_then_request_module(
2274                 find_compressor(ccp_option[0]),
2275                 "ppp-compress-%d", ccp_option[0]);
2276         if (!cp)
2277                 goto out;
2278
2279         err = -ENOBUFS;
2280         if (data.transmit) {
2281                 state = cp->comp_alloc(ccp_option, data.length);
2282                 if (state) {
2283                         ppp_xmit_lock(ppp);
2284                         ppp->xstate &= ~SC_COMP_RUN;
2285                         ocomp = ppp->xcomp;
2286                         ostate = ppp->xc_state;
2287                         ppp->xcomp = cp;
2288                         ppp->xc_state = state;
2289                         ppp_xmit_unlock(ppp);
2290                         if (ostate) {
2291                                 ocomp->comp_free(ostate);
2292                                 module_put(ocomp->owner);
2293                         }
2294                         err = 0;
2295                 } else
2296                         module_put(cp->owner);
2297
2298         } else {
2299                 state = cp->decomp_alloc(ccp_option, data.length);
2300                 if (state) {
2301                         ppp_recv_lock(ppp);
2302                         ppp->rstate &= ~SC_DECOMP_RUN;
2303                         ocomp = ppp->rcomp;
2304                         ostate = ppp->rc_state;
2305                         ppp->rcomp = cp;
2306                         ppp->rc_state = state;
2307                         ppp_recv_unlock(ppp);
2308                         if (ostate) {
2309                                 ocomp->decomp_free(ostate);
2310                                 module_put(ocomp->owner);
2311                         }
2312                         err = 0;
2313                 } else
2314                         module_put(cp->owner);
2315         }
2316
2317  out:
2318         return err;
2319 }
2320
2321 /*
2322  * Look at a CCP packet and update our state accordingly.
2323  * We assume the caller has the xmit or recv path locked.
2324  */
2325 static void
2326 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2327 {
2328         unsigned char *dp;
2329         int len;
2330
2331         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2332                 return; /* no header */
2333         dp = skb->data + 2;
2334
2335         switch (CCP_CODE(dp)) {
2336         case CCP_CONFREQ:
2337
2338                 /* A ConfReq starts negotiation of compression
2339                  * in one direction of transmission,
2340                  * and hence brings it down...but which way?
2341                  *
2342                  * Remember:
2343                  * A ConfReq indicates what the sender would like to receive
2344                  */
2345                 if(inbound)
2346                         /* He is proposing what I should send */
2347                         ppp->xstate &= ~SC_COMP_RUN;
2348                 else
2349                         /* I am proposing to what he should send */
2350                         ppp->rstate &= ~SC_DECOMP_RUN;
2351
2352                 break;
2353
2354         case CCP_TERMREQ:
2355         case CCP_TERMACK:
2356                 /*
2357                  * CCP is going down, both directions of transmission
2358                  */
2359                 ppp->rstate &= ~SC_DECOMP_RUN;
2360                 ppp->xstate &= ~SC_COMP_RUN;
2361                 break;
2362
2363         case CCP_CONFACK:
2364                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2365                         break;
2366                 len = CCP_LENGTH(dp);
2367                 if (!pskb_may_pull(skb, len + 2))
2368                         return;         /* too short */
2369                 dp += CCP_HDRLEN;
2370                 len -= CCP_HDRLEN;
2371                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2372                         break;
2373                 if (inbound) {
2374                         /* we will start receiving compressed packets */
2375                         if (!ppp->rc_state)
2376                                 break;
2377                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2378                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2379                                 ppp->rstate |= SC_DECOMP_RUN;
2380                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2381                         }
2382                 } else {
2383                         /* we will soon start sending compressed packets */
2384                         if (!ppp->xc_state)
2385                                 break;
2386                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2387                                         ppp->file.index, 0, ppp->debug))
2388                                 ppp->xstate |= SC_COMP_RUN;
2389                 }
2390                 break;
2391
2392         case CCP_RESETACK:
2393                 /* reset the [de]compressor */
2394                 if ((ppp->flags & SC_CCP_UP) == 0)
2395                         break;
2396                 if (inbound) {
2397                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2398                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2399                                 ppp->rstate &= ~SC_DC_ERROR;
2400                         }
2401                 } else {
2402                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2403                                 ppp->xcomp->comp_reset(ppp->xc_state);
2404                 }
2405                 break;
2406         }
2407 }
2408
2409 /* Free up compression resources. */
2410 static void
2411 ppp_ccp_closed(struct ppp *ppp)
2412 {
2413         void *xstate, *rstate;
2414         struct compressor *xcomp, *rcomp;
2415
2416         ppp_lock(ppp);
2417         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2418         ppp->xstate = 0;
2419         xcomp = ppp->xcomp;
2420         xstate = ppp->xc_state;
2421         ppp->xc_state = NULL;
2422         ppp->rstate = 0;
2423         rcomp = ppp->rcomp;
2424         rstate = ppp->rc_state;
2425         ppp->rc_state = NULL;
2426         ppp_unlock(ppp);
2427
2428         if (xstate) {
2429                 xcomp->comp_free(xstate);
2430                 module_put(xcomp->owner);
2431         }
2432         if (rstate) {
2433                 rcomp->decomp_free(rstate);
2434                 module_put(rcomp->owner);
2435         }
2436 }
2437
2438 /* List of compressors. */
2439 static LIST_HEAD(compressor_list);
2440 static DEFINE_SPINLOCK(compressor_list_lock);
2441
2442 struct compressor_entry {
2443         struct list_head list;
2444         struct compressor *comp;
2445 };
2446
2447 static struct compressor_entry *
2448 find_comp_entry(int proto)
2449 {
2450         struct compressor_entry *ce;
2451
2452         list_for_each_entry(ce, &compressor_list, list) {
2453                 if (ce->comp->compress_proto == proto)
2454                         return ce;
2455         }
2456         return NULL;
2457 }
2458
2459 /* Register a compressor */
2460 int
2461 ppp_register_compressor(struct compressor *cp)
2462 {
2463         struct compressor_entry *ce;
2464         int ret;
2465         spin_lock(&compressor_list_lock);
2466         ret = -EEXIST;
2467         if (find_comp_entry(cp->compress_proto))
2468                 goto out;
2469         ret = -ENOMEM;
2470         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2471         if (!ce)
2472                 goto out;
2473         ret = 0;
2474         ce->comp = cp;
2475         list_add(&ce->list, &compressor_list);
2476  out:
2477         spin_unlock(&compressor_list_lock);
2478         return ret;
2479 }
2480
2481 /* Unregister a compressor */
2482 void
2483 ppp_unregister_compressor(struct compressor *cp)
2484 {
2485         struct compressor_entry *ce;
2486
2487         spin_lock(&compressor_list_lock);
2488         ce = find_comp_entry(cp->compress_proto);
2489         if (ce && ce->comp == cp) {
2490                 list_del(&ce->list);
2491                 kfree(ce);
2492         }
2493         spin_unlock(&compressor_list_lock);
2494 }
2495
2496 /* Find a compressor. */
2497 static struct compressor *
2498 find_compressor(int type)
2499 {
2500         struct compressor_entry *ce;
2501         struct compressor *cp = NULL;
2502
2503         spin_lock(&compressor_list_lock);
2504         ce = find_comp_entry(type);
2505         if (ce) {
2506                 cp = ce->comp;
2507                 if (!try_module_get(cp->owner))
2508                         cp = NULL;
2509         }
2510         spin_unlock(&compressor_list_lock);
2511         return cp;
2512 }
2513
2514 /*
2515  * Miscelleneous stuff.
2516  */
2517
2518 static void
2519 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2520 {
2521         struct slcompress *vj = ppp->vj;
2522
2523         memset(st, 0, sizeof(*st));
2524         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2525         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2526         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2527         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2528         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2529         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2530         if (!vj)
2531                 return;
2532         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2533         st->vj.vjs_compressed = vj->sls_o_compressed;
2534         st->vj.vjs_searches = vj->sls_o_searches;
2535         st->vj.vjs_misses = vj->sls_o_misses;
2536         st->vj.vjs_errorin = vj->sls_i_error;
2537         st->vj.vjs_tossed = vj->sls_i_tossed;
2538         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2539         st->vj.vjs_compressedin = vj->sls_i_compressed;
2540 }
2541
2542 /*
2543  * Stuff for handling the lists of ppp units and channels
2544  * and for initialization.
2545  */
2546
2547 /*
2548  * Create a new ppp interface unit.  Fails if it can't allocate memory
2549  * or if there is already a unit with the requested number.
2550  * unit == -1 means allocate a new number.
2551  */
2552 static struct ppp *
2553 ppp_create_interface(struct net *net, int unit, int *retp)
2554 {
2555         struct ppp *ppp;
2556         struct ppp_net *pn;
2557         struct net_device *dev = NULL;
2558         int ret = -ENOMEM;
2559         int i;
2560
2561         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2562         if (!dev)
2563                 goto out1;
2564
2565         pn = ppp_pernet(net);
2566
2567         ppp = netdev_priv(dev);
2568         ppp->dev = dev;
2569         ppp->mru = PPP_MRU;
2570         init_ppp_file(&ppp->file, INTERFACE);
2571         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2572         for (i = 0; i < NUM_NP; ++i)
2573                 ppp->npmode[i] = NPMODE_PASS;
2574         INIT_LIST_HEAD(&ppp->channels);
2575         spin_lock_init(&ppp->rlock);
2576         spin_lock_init(&ppp->wlock);
2577 #ifdef CONFIG_PPP_MULTILINK
2578         ppp->minseq = -1;
2579         skb_queue_head_init(&ppp->mrq);
2580 #endif /* CONFIG_PPP_MULTILINK */
2581
2582         /*
2583          * drum roll: don't forget to set
2584          * the net device is belong to
2585          */
2586         dev_net_set(dev, net);
2587
2588         mutex_lock(&pn->all_ppp_mutex);
2589
2590         if (unit < 0) {
2591                 unit = unit_get(&pn->units_idr, ppp);
2592                 if (unit < 0) {
2593                         ret = unit;
2594                         goto out2;
2595                 }
2596         } else {
2597                 ret = -EEXIST;
2598                 if (unit_find(&pn->units_idr, unit))
2599                         goto out2; /* unit already exists */
2600                 /*
2601                  * if caller need a specified unit number
2602                  * lets try to satisfy him, otherwise --
2603                  * he should better ask us for new unit number
2604                  *
2605                  * NOTE: yes I know that returning EEXIST it's not
2606                  * fair but at least pppd will ask us to allocate
2607                  * new unit in this case so user is happy :)
2608                  */
2609                 unit = unit_set(&pn->units_idr, ppp, unit);
2610                 if (unit < 0)
2611                         goto out2;
2612         }
2613
2614         /* Initialize the new ppp unit */
2615         ppp->file.index = unit;
2616         sprintf(dev->name, "ppp%d", unit);
2617
2618         ret = register_netdev(dev);
2619         if (ret != 0) {
2620                 unit_put(&pn->units_idr, unit);
2621                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2622                        dev->name, ret);
2623                 goto out2;
2624         }
2625
2626         ppp->ppp_net = net;
2627
2628         atomic_inc(&ppp_unit_count);
2629         mutex_unlock(&pn->all_ppp_mutex);
2630
2631         *retp = 0;
2632         return ppp;
2633
2634 out2:
2635         mutex_unlock(&pn->all_ppp_mutex);
2636         free_netdev(dev);
2637 out1:
2638         *retp = ret;
2639         return NULL;
2640 }
2641
2642 /*
2643  * Initialize a ppp_file structure.
2644  */
2645 static void
2646 init_ppp_file(struct ppp_file *pf, int kind)
2647 {
2648         pf->kind = kind;
2649         skb_queue_head_init(&pf->xq);
2650         skb_queue_head_init(&pf->rq);
2651         atomic_set(&pf->refcnt, 1);
2652         init_waitqueue_head(&pf->rwait);
2653 }
2654
2655 /*
2656  * Take down a ppp interface unit - called when the owning file
2657  * (the one that created the unit) is closed or detached.
2658  */
2659 static void ppp_shutdown_interface(struct ppp *ppp)
2660 {
2661         struct ppp_net *pn;
2662
2663         pn = ppp_pernet(ppp->ppp_net);
2664         mutex_lock(&pn->all_ppp_mutex);
2665
2666         /* This will call dev_close() for us. */
2667         ppp_lock(ppp);
2668         if (!ppp->closing) {
2669                 ppp->closing = 1;
2670                 ppp_unlock(ppp);
2671                 unregister_netdev(ppp->dev);
2672                 unit_put(&pn->units_idr, ppp->file.index);
2673         } else
2674                 ppp_unlock(ppp);
2675
2676         ppp->file.dead = 1;
2677         ppp->owner = NULL;
2678         wake_up_interruptible(&ppp->file.rwait);
2679
2680         mutex_unlock(&pn->all_ppp_mutex);
2681 }
2682
2683 /*
2684  * Free the memory used by a ppp unit.  This is only called once
2685  * there are no channels connected to the unit and no file structs
2686  * that reference the unit.
2687  */
2688 static void ppp_destroy_interface(struct ppp *ppp)
2689 {
2690         atomic_dec(&ppp_unit_count);
2691
2692         if (!ppp->file.dead || ppp->n_channels) {
2693                 /* "can't happen" */
2694                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2695                        "n_channels=%d !\n", ppp, ppp->file.dead,
2696                        ppp->n_channels);
2697                 return;
2698         }
2699
2700         ppp_ccp_closed(ppp);
2701         if (ppp->vj) {
2702                 slhc_free(ppp->vj);
2703                 ppp->vj = NULL;
2704         }
2705         skb_queue_purge(&ppp->file.xq);
2706         skb_queue_purge(&ppp->file.rq);
2707 #ifdef CONFIG_PPP_MULTILINK
2708         skb_queue_purge(&ppp->mrq);
2709 #endif /* CONFIG_PPP_MULTILINK */
2710 #ifdef CONFIG_PPP_FILTER
2711         kfree(ppp->pass_filter);
2712         ppp->pass_filter = NULL;
2713         kfree(ppp->active_filter);
2714         ppp->active_filter = NULL;
2715 #endif /* CONFIG_PPP_FILTER */
2716
2717         kfree_skb(ppp->xmit_pending);
2718
2719         free_netdev(ppp->dev);
2720 }
2721
2722 /*
2723  * Locate an existing ppp unit.
2724  * The caller should have locked the all_ppp_mutex.
2725  */
2726 static struct ppp *
2727 ppp_find_unit(struct ppp_net *pn, int unit)
2728 {
2729         return unit_find(&pn->units_idr, unit);
2730 }
2731
2732 /*
2733  * Locate an existing ppp channel.
2734  * The caller should have locked the all_channels_lock.
2735  * First we look in the new_channels list, then in the
2736  * all_channels list.  If found in the new_channels list,
2737  * we move it to the all_channels list.  This is for speed
2738  * when we have a lot of channels in use.
2739  */
2740 static struct channel *
2741 ppp_find_channel(struct ppp_net *pn, int unit)
2742 {
2743         struct channel *pch;
2744
2745         list_for_each_entry(pch, &pn->new_channels, list) {
2746                 if (pch->file.index == unit) {
2747                         list_move(&pch->list, &pn->all_channels);
2748                         return pch;
2749                 }
2750         }
2751
2752         list_for_each_entry(pch, &pn->all_channels, list) {
2753                 if (pch->file.index == unit)
2754                         return pch;
2755         }
2756
2757         return NULL;
2758 }
2759
2760 /*
2761  * Connect a PPP channel to a PPP interface unit.
2762  */
2763 static int
2764 ppp_connect_channel(struct channel *pch, int unit)
2765 {
2766         struct ppp *ppp;
2767         struct ppp_net *pn;
2768         int ret = -ENXIO;
2769         int hdrlen;
2770
2771         pn = ppp_pernet(pch->chan_net);
2772
2773         mutex_lock(&pn->all_ppp_mutex);
2774         ppp = ppp_find_unit(pn, unit);
2775         if (!ppp)
2776                 goto out;
2777         write_lock_bh(&pch->upl);
2778         ret = -EINVAL;
2779         if (pch->ppp)
2780                 goto outl;
2781
2782         ppp_lock(ppp);
2783         if (pch->file.hdrlen > ppp->file.hdrlen)
2784                 ppp->file.hdrlen = pch->file.hdrlen;
2785         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2786         if (hdrlen > ppp->dev->hard_header_len)
2787                 ppp->dev->hard_header_len = hdrlen;
2788         list_add_tail(&pch->clist, &ppp->channels);
2789         ++ppp->n_channels;
2790         pch->ppp = ppp;
2791         atomic_inc(&ppp->file.refcnt);
2792         ppp_unlock(ppp);
2793         ret = 0;
2794
2795  outl:
2796         write_unlock_bh(&pch->upl);
2797  out:
2798         mutex_unlock(&pn->all_ppp_mutex);
2799         return ret;
2800 }
2801
2802 /*
2803  * Disconnect a channel from its ppp unit.
2804  */
2805 static int
2806 ppp_disconnect_channel(struct channel *pch)
2807 {
2808         struct ppp *ppp;
2809         int err = -EINVAL;
2810
2811         write_lock_bh(&pch->upl);
2812         ppp = pch->ppp;
2813         pch->ppp = NULL;
2814         write_unlock_bh(&pch->upl);
2815         if (ppp) {
2816                 /* remove it from the ppp unit's list */
2817                 ppp_lock(ppp);
2818                 list_del(&pch->clist);
2819                 if (--ppp->n_channels == 0)
2820                         wake_up_interruptible(&ppp->file.rwait);
2821                 ppp_unlock(ppp);
2822                 if (atomic_dec_and_test(&ppp->file.refcnt))
2823                         ppp_destroy_interface(ppp);
2824                 err = 0;
2825         }
2826         return err;
2827 }
2828
2829 /*
2830  * Free up the resources used by a ppp channel.
2831  */
2832 static void ppp_destroy_channel(struct channel *pch)
2833 {
2834         atomic_dec(&channel_count);
2835
2836         if (!pch->file.dead) {
2837                 /* "can't happen" */
2838                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2839                        pch);
2840                 return;
2841         }
2842         skb_queue_purge(&pch->file.xq);
2843         skb_queue_purge(&pch->file.rq);
2844         kfree(pch);
2845 }
2846
2847 static void __exit ppp_cleanup(void)
2848 {
2849         /* should never happen */
2850         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2851                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2852         unregister_chrdev(PPP_MAJOR, "ppp");
2853         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2854         class_destroy(ppp_class);
2855         unregister_pernet_device(&ppp_net_ops);
2856 }
2857
2858 /*
2859  * Units handling. Caller must protect concurrent access
2860  * by holding all_ppp_mutex
2861  */
2862
2863 static int __unit_alloc(struct idr *p, void *ptr, int n)
2864 {
2865         int unit, err;
2866
2867 again:
2868         if (!idr_pre_get(p, GFP_KERNEL)) {
2869                 printk(KERN_ERR "PPP: No free memory for idr\n");
2870                 return -ENOMEM;
2871         }
2872
2873         err = idr_get_new_above(p, ptr, n, &unit);
2874         if (err < 0) {
2875                 if (err == -EAGAIN)
2876                         goto again;
2877                 return err;
2878         }
2879
2880         return unit;
2881 }
2882
2883 /* associate pointer with specified number */
2884 static int unit_set(struct idr *p, void *ptr, int n)
2885 {
2886         int unit;
2887
2888         unit = __unit_alloc(p, ptr, n);
2889         if (unit < 0)
2890                 return unit;
2891         else if (unit != n) {
2892                 idr_remove(p, unit);
2893                 return -EINVAL;
2894         }
2895
2896         return unit;
2897 }
2898
2899 /* get new free unit number and associate pointer with it */
2900 static int unit_get(struct idr *p, void *ptr)
2901 {
2902         return __unit_alloc(p, ptr, 0);
2903 }
2904
2905 /* put unit number back to a pool */
2906 static void unit_put(struct idr *p, int n)
2907 {
2908         idr_remove(p, n);
2909 }
2910
2911 /* get pointer associated with the number */
2912 static void *unit_find(struct idr *p, int n)
2913 {
2914         return idr_find(p, n);
2915 }
2916
2917 /* Module/initialization stuff */
2918
2919 module_init(ppp_init);
2920 module_exit(ppp_cleanup);
2921
2922 EXPORT_SYMBOL(ppp_register_net_channel);
2923 EXPORT_SYMBOL(ppp_register_channel);
2924 EXPORT_SYMBOL(ppp_unregister_channel);
2925 EXPORT_SYMBOL(ppp_channel_index);
2926 EXPORT_SYMBOL(ppp_unit_number);
2927 EXPORT_SYMBOL(ppp_dev_name);
2928 EXPORT_SYMBOL(ppp_input);
2929 EXPORT_SYMBOL(ppp_input_error);
2930 EXPORT_SYMBOL(ppp_output_wakeup);
2931 EXPORT_SYMBOL(ppp_register_compressor);
2932 EXPORT_SYMBOL(ppp_unregister_compressor);
2933 MODULE_LICENSE("GPL");
2934 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
2935 MODULE_ALIAS("devname:ppp");