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