8ee91421db12133634a922d2d8d70c933e22c248
[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;
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;
868         int err;
869
870         pn = kzalloc(sizeof(*pn), GFP_KERNEL);
871         if (!pn)
872                 return -ENOMEM;
873
874         idr_init(&pn->units_idr);
875         mutex_init(&pn->all_ppp_mutex);
876
877         INIT_LIST_HEAD(&pn->all_channels);
878         INIT_LIST_HEAD(&pn->new_channels);
879
880         spin_lock_init(&pn->all_channels_lock);
881
882         err = net_assign_generic(net, ppp_net_id, pn);
883         if (err) {
884                 kfree(pn);
885                 return err;
886         }
887
888         return 0;
889 }
890
891 static __net_exit void ppp_exit_net(struct net *net)
892 {
893         struct ppp_net *pn;
894
895         pn = net_generic(net, ppp_net_id);
896         idr_destroy(&pn->units_idr);
897         /*
898          * if someone has cached our net then
899          * further net_generic call will return NULL
900          */
901         net_assign_generic(net, ppp_net_id, NULL);
902         kfree(pn);
903 }
904
905 static struct pernet_operations ppp_net_ops = {
906         .init = ppp_init_net,
907         .exit = ppp_exit_net,
908 };
909
910 #define PPP_MAJOR       108
911
912 /* Called at boot time if ppp is compiled into the kernel,
913    or at module load time (from init_module) if compiled as a module. */
914 static int __init ppp_init(void)
915 {
916         int err;
917
918         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
919
920         err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
921         if (err) {
922                 printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
923                 goto out;
924         }
925
926         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
927         if (err) {
928                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
929                 goto out_net;
930         }
931
932         ppp_class = class_create(THIS_MODULE, "ppp");
933         if (IS_ERR(ppp_class)) {
934                 err = PTR_ERR(ppp_class);
935                 goto out_chrdev;
936         }
937
938         /* not a big deal if we fail here :-) */
939         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
940
941         return 0;
942
943 out_chrdev:
944         unregister_chrdev(PPP_MAJOR, "ppp");
945 out_net:
946         unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
947 out:
948         return err;
949 }
950
951 /*
952  * Network interface unit routines.
953  */
954 static int
955 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
956 {
957         struct ppp *ppp = netdev_priv(dev);
958         int npi, proto;
959         unsigned char *pp;
960
961         npi = ethertype_to_npindex(ntohs(skb->protocol));
962         if (npi < 0)
963                 goto outf;
964
965         /* Drop, accept or reject the packet */
966         switch (ppp->npmode[npi]) {
967         case NPMODE_PASS:
968                 break;
969         case NPMODE_QUEUE:
970                 /* it would be nice to have a way to tell the network
971                    system to queue this one up for later. */
972                 goto outf;
973         case NPMODE_DROP:
974         case NPMODE_ERROR:
975                 goto outf;
976         }
977
978         /* Put the 2-byte PPP protocol number on the front,
979            making sure there is room for the address and control fields. */
980         if (skb_cow_head(skb, PPP_HDRLEN))
981                 goto outf;
982
983         pp = skb_push(skb, 2);
984         proto = npindex_to_proto[npi];
985         pp[0] = proto >> 8;
986         pp[1] = proto;
987
988         netif_stop_queue(dev);
989         skb_queue_tail(&ppp->file.xq, skb);
990         ppp_xmit_process(ppp);
991         return 0;
992
993  outf:
994         kfree_skb(skb);
995         ++dev->stats.tx_dropped;
996         return 0;
997 }
998
999 static int
1000 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1001 {
1002         struct ppp *ppp = netdev_priv(dev);
1003         int err = -EFAULT;
1004         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1005         struct ppp_stats stats;
1006         struct ppp_comp_stats cstats;
1007         char *vers;
1008
1009         switch (cmd) {
1010         case SIOCGPPPSTATS:
1011                 ppp_get_stats(ppp, &stats);
1012                 if (copy_to_user(addr, &stats, sizeof(stats)))
1013                         break;
1014                 err = 0;
1015                 break;
1016
1017         case SIOCGPPPCSTATS:
1018                 memset(&cstats, 0, sizeof(cstats));
1019                 if (ppp->xc_state)
1020                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1021                 if (ppp->rc_state)
1022                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1023                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1024                         break;
1025                 err = 0;
1026                 break;
1027
1028         case SIOCGPPPVER:
1029                 vers = PPP_VERSION;
1030                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1031                         break;
1032                 err = 0;
1033                 break;
1034
1035         default:
1036                 err = -EINVAL;
1037         }
1038
1039         return err;
1040 }
1041
1042 static const struct net_device_ops ppp_netdev_ops = {
1043         .ndo_start_xmit = ppp_start_xmit,
1044         .ndo_do_ioctl   = ppp_net_ioctl,
1045 };
1046
1047 static void ppp_setup(struct net_device *dev)
1048 {
1049         dev->netdev_ops = &ppp_netdev_ops;
1050         dev->hard_header_len = PPP_HDRLEN;
1051         dev->mtu = PPP_MTU;
1052         dev->addr_len = 0;
1053         dev->tx_queue_len = 3;
1054         dev->type = ARPHRD_PPP;
1055         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1056         dev->features |= NETIF_F_NETNS_LOCAL;
1057 }
1058
1059 /*
1060  * Transmit-side routines.
1061  */
1062
1063 /*
1064  * Called to do any work queued up on the transmit side
1065  * that can now be done.
1066  */
1067 static void
1068 ppp_xmit_process(struct ppp *ppp)
1069 {
1070         struct sk_buff *skb;
1071
1072         ppp_xmit_lock(ppp);
1073         if (!ppp->closing) {
1074                 ppp_push(ppp);
1075                 while (!ppp->xmit_pending
1076                        && (skb = skb_dequeue(&ppp->file.xq)))
1077                         ppp_send_frame(ppp, skb);
1078                 /* If there's no work left to do, tell the core net
1079                    code that we can accept some more. */
1080                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1081                         netif_wake_queue(ppp->dev);
1082         }
1083         ppp_xmit_unlock(ppp);
1084 }
1085
1086 static inline struct sk_buff *
1087 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1088 {
1089         struct sk_buff *new_skb;
1090         int len;
1091         int new_skb_size = ppp->dev->mtu +
1092                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1093         int compressor_skb_size = ppp->dev->mtu +
1094                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1095         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1096         if (!new_skb) {
1097                 if (net_ratelimit())
1098                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1099                 return NULL;
1100         }
1101         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1102                 skb_reserve(new_skb,
1103                             ppp->dev->hard_header_len - PPP_HDRLEN);
1104
1105         /* compressor still expects A/C bytes in hdr */
1106         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1107                                    new_skb->data, skb->len + 2,
1108                                    compressor_skb_size);
1109         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1110                 kfree_skb(skb);
1111                 skb = new_skb;
1112                 skb_put(skb, len);
1113                 skb_pull(skb, 2);       /* pull off A/C bytes */
1114         } else if (len == 0) {
1115                 /* didn't compress, or CCP not up yet */
1116                 kfree_skb(new_skb);
1117                 new_skb = skb;
1118         } else {
1119                 /*
1120                  * (len < 0)
1121                  * MPPE requires that we do not send unencrypted
1122                  * frames.  The compressor will return -1 if we
1123                  * should drop the frame.  We cannot simply test
1124                  * the compress_proto because MPPE and MPPC share
1125                  * the same number.
1126                  */
1127                 if (net_ratelimit())
1128                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1129                 kfree_skb(skb);
1130                 kfree_skb(new_skb);
1131                 new_skb = NULL;
1132         }
1133         return new_skb;
1134 }
1135
1136 /*
1137  * Compress and send a frame.
1138  * The caller should have locked the xmit path,
1139  * and xmit_pending should be 0.
1140  */
1141 static void
1142 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1143 {
1144         int proto = PPP_PROTO(skb);
1145         struct sk_buff *new_skb;
1146         int len;
1147         unsigned char *cp;
1148
1149         if (proto < 0x8000) {
1150 #ifdef CONFIG_PPP_FILTER
1151                 /* check if we should pass this packet */
1152                 /* the filter instructions are constructed assuming
1153                    a four-byte PPP header on each packet */
1154                 *skb_push(skb, 2) = 1;
1155                 if (ppp->pass_filter
1156                     && sk_run_filter(skb, ppp->pass_filter,
1157                                      ppp->pass_len) == 0) {
1158                         if (ppp->debug & 1)
1159                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1160                         kfree_skb(skb);
1161                         return;
1162                 }
1163                 /* if this packet passes the active filter, record the time */
1164                 if (!(ppp->active_filter
1165                       && sk_run_filter(skb, ppp->active_filter,
1166                                        ppp->active_len) == 0))
1167                         ppp->last_xmit = jiffies;
1168                 skb_pull(skb, 2);
1169 #else
1170                 /* for data packets, record the time */
1171                 ppp->last_xmit = jiffies;
1172 #endif /* CONFIG_PPP_FILTER */
1173         }
1174
1175         ++ppp->dev->stats.tx_packets;
1176         ppp->dev->stats.tx_bytes += skb->len - 2;
1177
1178         switch (proto) {
1179         case PPP_IP:
1180                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1181                         break;
1182                 /* try to do VJ TCP header compression */
1183                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1184                                     GFP_ATOMIC);
1185                 if (!new_skb) {
1186                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1187                         goto drop;
1188                 }
1189                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1190                 cp = skb->data + 2;
1191                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1192                                     new_skb->data + 2, &cp,
1193                                     !(ppp->flags & SC_NO_TCP_CCID));
1194                 if (cp == skb->data + 2) {
1195                         /* didn't compress */
1196                         kfree_skb(new_skb);
1197                 } else {
1198                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1199                                 proto = PPP_VJC_COMP;
1200                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1201                         } else {
1202                                 proto = PPP_VJC_UNCOMP;
1203                                 cp[0] = skb->data[2];
1204                         }
1205                         kfree_skb(skb);
1206                         skb = new_skb;
1207                         cp = skb_put(skb, len + 2);
1208                         cp[0] = 0;
1209                         cp[1] = proto;
1210                 }
1211                 break;
1212
1213         case PPP_CCP:
1214                 /* peek at outbound CCP frames */
1215                 ppp_ccp_peek(ppp, skb, 0);
1216                 break;
1217         }
1218
1219         /* try to do packet compression */
1220         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
1221             && proto != PPP_LCP && proto != PPP_CCP) {
1222                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1223                         if (net_ratelimit())
1224                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1225                         goto drop;
1226                 }
1227                 skb = pad_compress_skb(ppp, skb);
1228                 if (!skb)
1229                         goto drop;
1230         }
1231
1232         /*
1233          * If we are waiting for traffic (demand dialling),
1234          * queue it up for pppd to receive.
1235          */
1236         if (ppp->flags & SC_LOOP_TRAFFIC) {
1237                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1238                         goto drop;
1239                 skb_queue_tail(&ppp->file.rq, skb);
1240                 wake_up_interruptible(&ppp->file.rwait);
1241                 return;
1242         }
1243
1244         ppp->xmit_pending = skb;
1245         ppp_push(ppp);
1246         return;
1247
1248  drop:
1249         kfree_skb(skb);
1250         ++ppp->dev->stats.tx_errors;
1251 }
1252
1253 /*
1254  * Try to send the frame in xmit_pending.
1255  * The caller should have the xmit path locked.
1256  */
1257 static void
1258 ppp_push(struct ppp *ppp)
1259 {
1260         struct list_head *list;
1261         struct channel *pch;
1262         struct sk_buff *skb = ppp->xmit_pending;
1263
1264         if (!skb)
1265                 return;
1266
1267         list = &ppp->channels;
1268         if (list_empty(list)) {
1269                 /* nowhere to send the packet, just drop it */
1270                 ppp->xmit_pending = NULL;
1271                 kfree_skb(skb);
1272                 return;
1273         }
1274
1275         if ((ppp->flags & SC_MULTILINK) == 0) {
1276                 /* not doing multilink: send it down the first channel */
1277                 list = list->next;
1278                 pch = list_entry(list, struct channel, clist);
1279
1280                 spin_lock_bh(&pch->downl);
1281                 if (pch->chan) {
1282                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1283                                 ppp->xmit_pending = NULL;
1284                 } else {
1285                         /* channel got unregistered */
1286                         kfree_skb(skb);
1287                         ppp->xmit_pending = NULL;
1288                 }
1289                 spin_unlock_bh(&pch->downl);
1290                 return;
1291         }
1292
1293 #ifdef CONFIG_PPP_MULTILINK
1294         /* Multilink: fragment the packet over as many links
1295            as can take the packet at the moment. */
1296         if (!ppp_mp_explode(ppp, skb))
1297                 return;
1298 #endif /* CONFIG_PPP_MULTILINK */
1299
1300         ppp->xmit_pending = NULL;
1301         kfree_skb(skb);
1302 }
1303
1304 #ifdef CONFIG_PPP_MULTILINK
1305 /*
1306  * Divide a packet to be transmitted into fragments and
1307  * send them out the individual links.
1308  */
1309 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1310 {
1311         int     len, totlen;
1312         int     i, bits, hdrlen, mtu;
1313         int     flen;
1314         int     navail, nfree, nzero;
1315         int     nbigger;
1316         int     totspeed;
1317         int     totfree;
1318         unsigned char *p, *q;
1319         struct list_head *list;
1320         struct channel *pch;
1321         struct sk_buff *frag;
1322         struct ppp_channel *chan;
1323
1324         totspeed = 0; /*total bitrate of the bundle*/
1325         nfree = 0;      /* # channels which     have no packet already queued */
1326         navail = 0;     /* total # of usable channels (not deregistered) */
1327         nzero = 0; /* number of channels with zero speed associated*/
1328         totfree = 0; /*total # of channels available and
1329                                   *having no queued packets before
1330                                   *starting the fragmentation*/
1331
1332         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1333         i =     0;
1334         list_for_each_entry(pch, &ppp->channels, clist) {
1335                 navail += pch->avail = (pch->chan != NULL);
1336                 pch->speed = pch->chan->speed;
1337                 if (pch->avail) {
1338                         if (skb_queue_empty(&pch->file.xq) ||
1339                                 !pch->had_frag) {
1340                                         if (pch->speed == 0)
1341                                                 nzero++;
1342                                         else
1343                                                 totspeed += pch->speed;
1344
1345                                         pch->avail = 2;
1346                                         ++nfree;
1347                                         ++totfree;
1348                                 }
1349                         if (!pch->had_frag && i < ppp->nxchan)
1350                                 ppp->nxchan     = i;
1351                 }
1352                 ++i;
1353         }
1354         /*
1355          * Don't start sending this     packet unless at least half     of
1356          * the channels are     free.  This     gives much better TCP
1357          * performance if we have a     lot     of channels.
1358          */
1359         if (nfree == 0 || nfree < navail / 2)
1360                 return 0; /* can't take now, leave it in xmit_pending   */
1361
1362         /* Do protocol field compression (XXX this should be optional) */
1363         p =     skb->data;
1364         len     = skb->len;
1365         if (*p == 0) {
1366                 ++p;
1367                 --len;
1368         }
1369
1370         totlen = len;
1371         nbigger = len % nfree;
1372
1373         /* skip to the channel after the one we last used
1374            and start at that one */
1375         list = &ppp->channels;
1376         for     (i = 0; i <     ppp->nxchan; ++i) {
1377                 list = list->next;
1378                 if (list ==     &ppp->channels) {
1379                         i =     0;
1380                         break;
1381                 }
1382         }
1383
1384         /* create a     fragment for each channel */
1385         bits = B;
1386         while (nfree > 0 &&     len     > 0) {
1387                 list = list->next;
1388                 if (list ==     &ppp->channels) {
1389                         i =     0;
1390                         continue;
1391                 }
1392                 pch     = list_entry(list, struct channel, clist);
1393                 ++i;
1394                 if (!pch->avail)
1395                         continue;
1396
1397                 /*
1398                  * Skip this channel if it has a fragment pending already and
1399                  * we haven't given     a fragment to all of the free channels.
1400                  */
1401                 if (pch->avail == 1) {
1402                         if (nfree >     0)
1403                                 continue;
1404                 } else {
1405                         pch->avail = 1;
1406                 }
1407
1408                 /* check the channel's mtu and whether it is still attached. */
1409                 spin_lock_bh(&pch->downl);
1410                 if (pch->chan == NULL) {
1411                         /* can't use this channel, it's being deregistered */
1412                         if (pch->speed == 0)
1413                                 nzero--;
1414                         else
1415                                 totspeed -=     pch->speed;
1416
1417                         spin_unlock_bh(&pch->downl);
1418                         pch->avail = 0;
1419                         totlen = len;
1420                         totfree--;
1421                         nfree--;
1422                         if (--navail == 0)
1423                                 break;
1424                         continue;
1425                 }
1426
1427                 /*
1428                 *if the channel speed is not set divide
1429                 *the packet     evenly among the free channels;
1430                 *otherwise divide it according to the speed
1431                 *of the channel we are going to transmit on
1432                 */
1433                 if (pch->speed == 0) {
1434                         flen = totlen/nfree     ;
1435                         if (nbigger > 0) {
1436                                 flen++;
1437                                 nbigger--;
1438                         }
1439                 } else {
1440                         flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1441                                 ((totspeed*totfree)/pch->speed)) - hdrlen;
1442                         if (nbigger > 0) {
1443                                 flen += ((totfree - nzero)*pch->speed)/totspeed;
1444                                 nbigger -= ((totfree - nzero)*pch->speed)/
1445                                                         totspeed;
1446                         }
1447                 }
1448                 nfree--;
1449
1450                 /*
1451                  *check if we are on the last channel or
1452                  *we exceded the lenght of the data     to
1453                  *fragment
1454                  */
1455                 if ((nfree == 0) || (flen > len))
1456                         flen = len;
1457                 /*
1458                  *it is not worth to tx on slow channels:
1459                  *in that case from the resulting flen according to the
1460                  *above formula will be equal or less than zero.
1461                  *Skip the channel in this case
1462                  */
1463                 if (flen <=     0) {
1464                         pch->avail = 2;
1465                         spin_unlock_bh(&pch->downl);
1466                         continue;
1467                 }
1468
1469                 mtu     = pch->chan->mtu + 2 - hdrlen;
1470                 if (mtu < 4)
1471                         mtu     = 4;
1472                 if (flen > mtu)
1473                         flen = mtu;
1474                 if (flen ==     len)
1475                         bits |= E;
1476                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1477                 if (!frag)
1478                         goto noskb;
1479                 q =     skb_put(frag, flen + hdrlen);
1480
1481                 /* make the     MP header */
1482                 q[0] = PPP_MP >> 8;
1483                 q[1] = PPP_MP;
1484                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1485                         q[2] = bits     + ((ppp->nxseq >> 8) & 0xf);
1486                         q[3] = ppp->nxseq;
1487                 } else {
1488                         q[2] = bits;
1489                         q[3] = ppp->nxseq >> 16;
1490                         q[4] = ppp->nxseq >> 8;
1491                         q[5] = ppp->nxseq;
1492                 }
1493
1494                 memcpy(q + hdrlen, p, flen);
1495
1496                 /* try to send it down the channel */
1497                 chan = pch->chan;
1498                 if (!skb_queue_empty(&pch->file.xq)     ||
1499                         !chan->ops->start_xmit(chan, frag))
1500                         skb_queue_tail(&pch->file.xq, frag);
1501                 pch->had_frag = 1;
1502                 p += flen;
1503                 len     -= flen;
1504                 ++ppp->nxseq;
1505                 bits = 0;
1506                 spin_unlock_bh(&pch->downl);
1507         }
1508         ppp->nxchan     = i;
1509
1510         return 1;
1511
1512  noskb:
1513         spin_unlock_bh(&pch->downl);
1514         if (ppp->debug & 1)
1515                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1516         ++ppp->dev->stats.tx_errors;
1517         ++ppp->nxseq;
1518         return 1;       /* abandon the frame */
1519 }
1520 #endif /* CONFIG_PPP_MULTILINK */
1521
1522 /*
1523  * Try to send data out on a channel.
1524  */
1525 static void
1526 ppp_channel_push(struct channel *pch)
1527 {
1528         struct sk_buff *skb;
1529         struct ppp *ppp;
1530
1531         spin_lock_bh(&pch->downl);
1532         if (pch->chan) {
1533                 while (!skb_queue_empty(&pch->file.xq)) {
1534                         skb = skb_dequeue(&pch->file.xq);
1535                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1536                                 /* put the packet back and try again later */
1537                                 skb_queue_head(&pch->file.xq, skb);
1538                                 break;
1539                         }
1540                 }
1541         } else {
1542                 /* channel got deregistered */
1543                 skb_queue_purge(&pch->file.xq);
1544         }
1545         spin_unlock_bh(&pch->downl);
1546         /* see if there is anything from the attached unit to be sent */
1547         if (skb_queue_empty(&pch->file.xq)) {
1548                 read_lock_bh(&pch->upl);
1549                 ppp = pch->ppp;
1550                 if (ppp)
1551                         ppp_xmit_process(ppp);
1552                 read_unlock_bh(&pch->upl);
1553         }
1554 }
1555
1556 /*
1557  * Receive-side routines.
1558  */
1559
1560 /* misuse a few fields of the skb for MP reconstruction */
1561 #define sequence        priority
1562 #define BEbits          cb[0]
1563
1564 static inline void
1565 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1566 {
1567         ppp_recv_lock(ppp);
1568         if (!ppp->closing)
1569                 ppp_receive_frame(ppp, skb, pch);
1570         else
1571                 kfree_skb(skb);
1572         ppp_recv_unlock(ppp);
1573 }
1574
1575 void
1576 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1577 {
1578         struct channel *pch = chan->ppp;
1579         int proto;
1580
1581         if (!pch || skb->len == 0) {
1582                 kfree_skb(skb);
1583                 return;
1584         }
1585
1586         proto = PPP_PROTO(skb);
1587         read_lock_bh(&pch->upl);
1588         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1589                 /* put it on the channel queue */
1590                 skb_queue_tail(&pch->file.rq, skb);
1591                 /* drop old frames if queue too long */
1592                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1593                        && (skb = skb_dequeue(&pch->file.rq)))
1594                         kfree_skb(skb);
1595                 wake_up_interruptible(&pch->file.rwait);
1596         } else {
1597                 ppp_do_recv(pch->ppp, skb, pch);
1598         }
1599         read_unlock_bh(&pch->upl);
1600 }
1601
1602 /* Put a 0-length skb in the receive queue as an error indication */
1603 void
1604 ppp_input_error(struct ppp_channel *chan, int code)
1605 {
1606         struct channel *pch = chan->ppp;
1607         struct sk_buff *skb;
1608
1609         if (!pch)
1610                 return;
1611
1612         read_lock_bh(&pch->upl);
1613         if (pch->ppp) {
1614                 skb = alloc_skb(0, GFP_ATOMIC);
1615                 if (skb) {
1616                         skb->len = 0;           /* probably unnecessary */
1617                         skb->cb[0] = code;
1618                         ppp_do_recv(pch->ppp, skb, pch);
1619                 }
1620         }
1621         read_unlock_bh(&pch->upl);
1622 }
1623
1624 /*
1625  * We come in here to process a received frame.
1626  * The receive side of the ppp unit is locked.
1627  */
1628 static void
1629 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1630 {
1631         if (pskb_may_pull(skb, 2)) {
1632 #ifdef CONFIG_PPP_MULTILINK
1633                 /* XXX do channel-level decompression here */
1634                 if (PPP_PROTO(skb) == PPP_MP)
1635                         ppp_receive_mp_frame(ppp, skb, pch);
1636                 else
1637 #endif /* CONFIG_PPP_MULTILINK */
1638                         ppp_receive_nonmp_frame(ppp, skb);
1639                 return;
1640         }
1641
1642         if (skb->len > 0)
1643                 /* note: a 0-length skb is used as an error indication */
1644                 ++ppp->dev->stats.rx_length_errors;
1645
1646         kfree_skb(skb);
1647         ppp_receive_error(ppp);
1648 }
1649
1650 static void
1651 ppp_receive_error(struct ppp *ppp)
1652 {
1653         ++ppp->dev->stats.rx_errors;
1654         if (ppp->vj)
1655                 slhc_toss(ppp->vj);
1656 }
1657
1658 static void
1659 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1660 {
1661         struct sk_buff *ns;
1662         int proto, len, npi;
1663
1664         /*
1665          * Decompress the frame, if compressed.
1666          * Note that some decompressors need to see uncompressed frames
1667          * that come in as well as compressed frames.
1668          */
1669         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
1670             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1671                 skb = ppp_decompress_frame(ppp, skb);
1672
1673         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1674                 goto err;
1675
1676         proto = PPP_PROTO(skb);
1677         switch (proto) {
1678         case PPP_VJC_COMP:
1679                 /* decompress VJ compressed packets */
1680                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1681                         goto err;
1682
1683                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1684                         /* copy to a new sk_buff with more tailroom */
1685                         ns = dev_alloc_skb(skb->len + 128);
1686                         if (!ns) {
1687                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1688                                 goto err;
1689                         }
1690                         skb_reserve(ns, 2);
1691                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1692                         kfree_skb(skb);
1693                         skb = ns;
1694                 }
1695                 else
1696                         skb->ip_summed = CHECKSUM_NONE;
1697
1698                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1699                 if (len <= 0) {
1700                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1701                         goto err;
1702                 }
1703                 len += 2;
1704                 if (len > skb->len)
1705                         skb_put(skb, len - skb->len);
1706                 else if (len < skb->len)
1707                         skb_trim(skb, len);
1708                 proto = PPP_IP;
1709                 break;
1710
1711         case PPP_VJC_UNCOMP:
1712                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1713                         goto err;
1714
1715                 /* Until we fix the decompressor need to make sure
1716                  * data portion is linear.
1717                  */
1718                 if (!pskb_may_pull(skb, skb->len))
1719                         goto err;
1720
1721                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1722                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1723                         goto err;
1724                 }
1725                 proto = PPP_IP;
1726                 break;
1727
1728         case PPP_CCP:
1729                 ppp_ccp_peek(ppp, skb, 1);
1730                 break;
1731         }
1732
1733         ++ppp->dev->stats.rx_packets;
1734         ppp->dev->stats.rx_bytes += skb->len - 2;
1735
1736         npi = proto_to_npindex(proto);
1737         if (npi < 0) {
1738                 /* control or unknown frame - pass it to pppd */
1739                 skb_queue_tail(&ppp->file.rq, skb);
1740                 /* limit queue length by dropping old frames */
1741                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1742                        && (skb = skb_dequeue(&ppp->file.rq)))
1743                         kfree_skb(skb);
1744                 /* wake up any process polling or blocking on read */
1745                 wake_up_interruptible(&ppp->file.rwait);
1746
1747         } else {
1748                 /* network protocol frame - give it to the kernel */
1749
1750 #ifdef CONFIG_PPP_FILTER
1751                 /* check if the packet passes the pass and active filters */
1752                 /* the filter instructions are constructed assuming
1753                    a four-byte PPP header on each packet */
1754                 if (ppp->pass_filter || ppp->active_filter) {
1755                         if (skb_cloned(skb) &&
1756                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1757                                 goto err;
1758
1759                         *skb_push(skb, 2) = 0;
1760                         if (ppp->pass_filter
1761                             && sk_run_filter(skb, ppp->pass_filter,
1762                                              ppp->pass_len) == 0) {
1763                                 if (ppp->debug & 1)
1764                                         printk(KERN_DEBUG "PPP: inbound frame "
1765                                                "not passed\n");
1766                                 kfree_skb(skb);
1767                                 return;
1768                         }
1769                         if (!(ppp->active_filter
1770                               && sk_run_filter(skb, ppp->active_filter,
1771                                                ppp->active_len) == 0))
1772                                 ppp->last_recv = jiffies;
1773                         __skb_pull(skb, 2);
1774                 } else
1775 #endif /* CONFIG_PPP_FILTER */
1776                         ppp->last_recv = jiffies;
1777
1778                 if ((ppp->dev->flags & IFF_UP) == 0
1779                     || ppp->npmode[npi] != NPMODE_PASS) {
1780                         kfree_skb(skb);
1781                 } else {
1782                         /* chop off protocol */
1783                         skb_pull_rcsum(skb, 2);
1784                         skb->dev = ppp->dev;
1785                         skb->protocol = htons(npindex_to_ethertype[npi]);
1786                         skb_reset_mac_header(skb);
1787                         netif_rx(skb);
1788                 }
1789         }
1790         return;
1791
1792  err:
1793         kfree_skb(skb);
1794         ppp_receive_error(ppp);
1795 }
1796
1797 static struct sk_buff *
1798 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1799 {
1800         int proto = PPP_PROTO(skb);
1801         struct sk_buff *ns;
1802         int len;
1803
1804         /* Until we fix all the decompressor's need to make sure
1805          * data portion is linear.
1806          */
1807         if (!pskb_may_pull(skb, skb->len))
1808                 goto err;
1809
1810         if (proto == PPP_COMP) {
1811                 int obuff_size;
1812
1813                 switch(ppp->rcomp->compress_proto) {
1814                 case CI_MPPE:
1815                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1816                         break;
1817                 default:
1818                         obuff_size = ppp->mru + PPP_HDRLEN;
1819                         break;
1820                 }
1821
1822                 ns = dev_alloc_skb(obuff_size);
1823                 if (!ns) {
1824                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1825                         goto err;
1826                 }
1827                 /* the decompressor still expects the A/C bytes in the hdr */
1828                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1829                                 skb->len + 2, ns->data, obuff_size);
1830                 if (len < 0) {
1831                         /* Pass the compressed frame to pppd as an
1832                            error indication. */
1833                         if (len == DECOMP_FATALERROR)
1834                                 ppp->rstate |= SC_DC_FERROR;
1835                         kfree_skb(ns);
1836                         goto err;
1837                 }
1838
1839                 kfree_skb(skb);
1840                 skb = ns;
1841                 skb_put(skb, len);
1842                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1843
1844         } else {
1845                 /* Uncompressed frame - pass to decompressor so it
1846                    can update its dictionary if necessary. */
1847                 if (ppp->rcomp->incomp)
1848                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1849                                            skb->len + 2);
1850         }
1851
1852         return skb;
1853
1854  err:
1855         ppp->rstate |= SC_DC_ERROR;
1856         ppp_receive_error(ppp);
1857         return skb;
1858 }
1859
1860 #ifdef CONFIG_PPP_MULTILINK
1861 /*
1862  * Receive a multilink frame.
1863  * We put it on the reconstruction queue and then pull off
1864  * as many completed frames as we can.
1865  */
1866 static void
1867 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1868 {
1869         u32 mask, seq;
1870         struct channel *ch;
1871         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1872
1873         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1874                 goto err;               /* no good, throw it away */
1875
1876         /* Decode sequence number and begin/end bits */
1877         if (ppp->flags & SC_MP_SHORTSEQ) {
1878                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1879                 mask = 0xfff;
1880         } else {
1881                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1882                 mask = 0xffffff;
1883         }
1884         skb->BEbits = skb->data[2];
1885         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1886
1887         /*
1888          * Do protocol ID decompression on the first fragment of each packet.
1889          */
1890         if ((skb->BEbits & B) && (skb->data[0] & 1))
1891                 *skb_push(skb, 1) = 0;
1892
1893         /*
1894          * Expand sequence number to 32 bits, making it as close
1895          * as possible to ppp->minseq.
1896          */
1897         seq |= ppp->minseq & ~mask;
1898         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1899                 seq += mask + 1;
1900         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1901                 seq -= mask + 1;        /* should never happen */
1902         skb->sequence = seq;
1903         pch->lastseq = seq;
1904
1905         /*
1906          * If this packet comes before the next one we were expecting,
1907          * drop it.
1908          */
1909         if (seq_before(seq, ppp->nextseq)) {
1910                 kfree_skb(skb);
1911                 ++ppp->dev->stats.rx_dropped;
1912                 ppp_receive_error(ppp);
1913                 return;
1914         }
1915
1916         /*
1917          * Reevaluate minseq, the minimum over all channels of the
1918          * last sequence number received on each channel.  Because of
1919          * the increasing sequence number rule, we know that any fragment
1920          * before `minseq' which hasn't arrived is never going to arrive.
1921          * The list of channels can't change because we have the receive
1922          * side of the ppp unit locked.
1923          */
1924         list_for_each_entry(ch, &ppp->channels, clist) {
1925                 if (seq_before(ch->lastseq, seq))
1926                         seq = ch->lastseq;
1927         }
1928         if (seq_before(ppp->minseq, seq))
1929                 ppp->minseq = seq;
1930
1931         /* Put the fragment on the reconstruction queue */
1932         ppp_mp_insert(ppp, skb);
1933
1934         /* If the queue is getting long, don't wait any longer for packets
1935            before the start of the queue. */
1936         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1937                 struct sk_buff *skb = skb_peek(&ppp->mrq);
1938                 if (seq_before(ppp->minseq, skb->sequence))
1939                         ppp->minseq = skb->sequence;
1940         }
1941
1942         /* Pull completed packets off the queue and receive them. */
1943         while ((skb = ppp_mp_reconstruct(ppp)))
1944                 ppp_receive_nonmp_frame(ppp, skb);
1945
1946         return;
1947
1948  err:
1949         kfree_skb(skb);
1950         ppp_receive_error(ppp);
1951 }
1952
1953 /*
1954  * Insert a fragment on the MP reconstruction queue.
1955  * The queue is ordered by increasing sequence number.
1956  */
1957 static void
1958 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1959 {
1960         struct sk_buff *p;
1961         struct sk_buff_head *list = &ppp->mrq;
1962         u32 seq = skb->sequence;
1963
1964         /* N.B. we don't need to lock the list lock because we have the
1965            ppp unit receive-side lock. */
1966         skb_queue_walk(list, p) {
1967                 if (seq_before(seq, p->sequence))
1968                         break;
1969         }
1970         __skb_queue_before(list, p, skb);
1971 }
1972
1973 /*
1974  * Reconstruct a packet from the MP fragment queue.
1975  * We go through increasing sequence numbers until we find a
1976  * complete packet, or we get to the sequence number for a fragment
1977  * which hasn't arrived but might still do so.
1978  */
1979 static struct sk_buff *
1980 ppp_mp_reconstruct(struct ppp *ppp)
1981 {
1982         u32 seq = ppp->nextseq;
1983         u32 minseq = ppp->minseq;
1984         struct sk_buff_head *list = &ppp->mrq;
1985         struct sk_buff *p, *next;
1986         struct sk_buff *head, *tail;
1987         struct sk_buff *skb = NULL;
1988         int lost = 0, len = 0;
1989
1990         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1991                 return NULL;
1992         head = list->next;
1993         tail = NULL;
1994         for (p = head; p != (struct sk_buff *) list; p = next) {
1995                 next = p->next;
1996                 if (seq_before(p->sequence, seq)) {
1997                         /* this can't happen, anyway ignore the skb */
1998                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1999                                p->sequence, seq);
2000                         head = next;
2001                         continue;
2002                 }
2003                 if (p->sequence != seq) {
2004                         /* Fragment `seq' is missing.  If it is after
2005                            minseq, it might arrive later, so stop here. */
2006                         if (seq_after(seq, minseq))
2007                                 break;
2008                         /* Fragment `seq' is lost, keep going. */
2009                         lost = 1;
2010                         seq = seq_before(minseq, p->sequence)?
2011                                 minseq + 1: p->sequence;
2012                         next = p;
2013                         continue;
2014                 }
2015
2016                 /*
2017                  * At this point we know that all the fragments from
2018                  * ppp->nextseq to seq are either present or lost.
2019                  * Also, there are no complete packets in the queue
2020                  * that have no missing fragments and end before this
2021                  * fragment.
2022                  */
2023
2024                 /* B bit set indicates this fragment starts a packet */
2025                 if (p->BEbits & B) {
2026                         head = p;
2027                         lost = 0;
2028                         len = 0;
2029                 }
2030
2031                 len += p->len;
2032
2033                 /* Got a complete packet yet? */
2034                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
2035                         if (len > ppp->mrru + 2) {
2036                                 ++ppp->dev->stats.rx_length_errors;
2037                                 printk(KERN_DEBUG "PPP: reconstructed packet"
2038                                        " is too long (%d)\n", len);
2039                         } else if (p == head) {
2040                                 /* fragment is complete packet - reuse skb */
2041                                 tail = p;
2042                                 skb = skb_get(p);
2043                                 break;
2044                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
2045                                 ++ppp->dev->stats.rx_missed_errors;
2046                                 printk(KERN_DEBUG "PPP: no memory for "
2047                                        "reconstructed packet");
2048                         } else {
2049                                 tail = p;
2050                                 break;
2051                         }
2052                         ppp->nextseq = seq + 1;
2053                 }
2054
2055                 /*
2056                  * If this is the ending fragment of a packet,
2057                  * and we haven't found a complete valid packet yet,
2058                  * we can discard up to and including this fragment.
2059                  */
2060                 if (p->BEbits & E)
2061                         head = next;
2062
2063                 ++seq;
2064         }
2065
2066         /* If we have a complete packet, copy it all into one skb. */
2067         if (tail != NULL) {
2068                 /* If we have discarded any fragments,
2069                    signal a receive error. */
2070                 if (head->sequence != ppp->nextseq) {
2071                         if (ppp->debug & 1)
2072                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
2073                                        ppp->nextseq, head->sequence-1);
2074                         ++ppp->dev->stats.rx_dropped;
2075                         ppp_receive_error(ppp);
2076                 }
2077
2078                 if (head != tail)
2079                         /* copy to a single skb */
2080                         for (p = head; p != tail->next; p = p->next)
2081                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
2082                 ppp->nextseq = tail->sequence + 1;
2083                 head = tail->next;
2084         }
2085
2086         /* Discard all the skbuffs that we have copied the data out of
2087            or that we can't use. */
2088         while ((p = list->next) != head) {
2089                 __skb_unlink(p, list);
2090                 kfree_skb(p);
2091         }
2092
2093         return skb;
2094 }
2095 #endif /* CONFIG_PPP_MULTILINK */
2096
2097 /*
2098  * Channel interface.
2099  */
2100
2101 /* Create a new, unattached ppp channel. */
2102 int ppp_register_channel(struct ppp_channel *chan)
2103 {
2104         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2105 }
2106
2107 /* Create a new, unattached ppp channel for specified net. */
2108 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2109 {
2110         struct channel *pch;
2111         struct ppp_net *pn;
2112
2113         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2114         if (!pch)
2115                 return -ENOMEM;
2116
2117         pn = ppp_pernet(net);
2118
2119         pch->ppp = NULL;
2120         pch->chan = chan;
2121         pch->chan_net = net;
2122         chan->ppp = pch;
2123         init_ppp_file(&pch->file, CHANNEL);
2124         pch->file.hdrlen = chan->hdrlen;
2125 #ifdef CONFIG_PPP_MULTILINK
2126         pch->lastseq = -1;
2127 #endif /* CONFIG_PPP_MULTILINK */
2128         init_rwsem(&pch->chan_sem);
2129         spin_lock_init(&pch->downl);
2130         rwlock_init(&pch->upl);
2131
2132         spin_lock_bh(&pn->all_channels_lock);
2133         pch->file.index = ++pn->last_channel_index;
2134         list_add(&pch->list, &pn->new_channels);
2135         atomic_inc(&channel_count);
2136         spin_unlock_bh(&pn->all_channels_lock);
2137
2138         return 0;
2139 }
2140
2141 /*
2142  * Return the index of a channel.
2143  */
2144 int ppp_channel_index(struct ppp_channel *chan)
2145 {
2146         struct channel *pch = chan->ppp;
2147
2148         if (pch)
2149                 return pch->file.index;
2150         return -1;
2151 }
2152
2153 /*
2154  * Return the PPP unit number to which a channel is connected.
2155  */
2156 int ppp_unit_number(struct ppp_channel *chan)
2157 {
2158         struct channel *pch = chan->ppp;
2159         int unit = -1;
2160
2161         if (pch) {
2162                 read_lock_bh(&pch->upl);
2163                 if (pch->ppp)
2164                         unit = pch->ppp->file.index;
2165                 read_unlock_bh(&pch->upl);
2166         }
2167         return unit;
2168 }
2169
2170 /*
2171  * Disconnect a channel from the generic layer.
2172  * This must be called in process context.
2173  */
2174 void
2175 ppp_unregister_channel(struct ppp_channel *chan)
2176 {
2177         struct channel *pch = chan->ppp;
2178         struct ppp_net *pn;
2179
2180         if (!pch)
2181                 return;         /* should never happen */
2182
2183         chan->ppp = NULL;
2184
2185         /*
2186          * This ensures that we have returned from any calls into the
2187          * the channel's start_xmit or ioctl routine before we proceed.
2188          */
2189         down_write(&pch->chan_sem);
2190         spin_lock_bh(&pch->downl);
2191         pch->chan = NULL;
2192         spin_unlock_bh(&pch->downl);
2193         up_write(&pch->chan_sem);
2194         ppp_disconnect_channel(pch);
2195
2196         pn = ppp_pernet(pch->chan_net);
2197         spin_lock_bh(&pn->all_channels_lock);
2198         list_del(&pch->list);
2199         spin_unlock_bh(&pn->all_channels_lock);
2200
2201         pch->file.dead = 1;
2202         wake_up_interruptible(&pch->file.rwait);
2203         if (atomic_dec_and_test(&pch->file.refcnt))
2204                 ppp_destroy_channel(pch);
2205 }
2206
2207 /*
2208  * Callback from a channel when it can accept more to transmit.
2209  * This should be called at BH/softirq level, not interrupt level.
2210  */
2211 void
2212 ppp_output_wakeup(struct ppp_channel *chan)
2213 {
2214         struct channel *pch = chan->ppp;
2215
2216         if (!pch)
2217                 return;
2218         ppp_channel_push(pch);
2219 }
2220
2221 /*
2222  * Compression control.
2223  */
2224
2225 /* Process the PPPIOCSCOMPRESS ioctl. */
2226 static int
2227 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2228 {
2229         int err;
2230         struct compressor *cp, *ocomp;
2231         struct ppp_option_data data;
2232         void *state, *ostate;
2233         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2234
2235         err = -EFAULT;
2236         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2237             || (data.length <= CCP_MAX_OPTION_LENGTH
2238                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2239                 goto out;
2240         err = -EINVAL;
2241         if (data.length > CCP_MAX_OPTION_LENGTH
2242             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2243                 goto out;
2244
2245         cp = try_then_request_module(
2246                 find_compressor(ccp_option[0]),
2247                 "ppp-compress-%d", ccp_option[0]);
2248         if (!cp)
2249                 goto out;
2250
2251         err = -ENOBUFS;
2252         if (data.transmit) {
2253                 state = cp->comp_alloc(ccp_option, data.length);
2254                 if (state) {
2255                         ppp_xmit_lock(ppp);
2256                         ppp->xstate &= ~SC_COMP_RUN;
2257                         ocomp = ppp->xcomp;
2258                         ostate = ppp->xc_state;
2259                         ppp->xcomp = cp;
2260                         ppp->xc_state = state;
2261                         ppp_xmit_unlock(ppp);
2262                         if (ostate) {
2263                                 ocomp->comp_free(ostate);
2264                                 module_put(ocomp->owner);
2265                         }
2266                         err = 0;
2267                 } else
2268                         module_put(cp->owner);
2269
2270         } else {
2271                 state = cp->decomp_alloc(ccp_option, data.length);
2272                 if (state) {
2273                         ppp_recv_lock(ppp);
2274                         ppp->rstate &= ~SC_DECOMP_RUN;
2275                         ocomp = ppp->rcomp;
2276                         ostate = ppp->rc_state;
2277                         ppp->rcomp = cp;
2278                         ppp->rc_state = state;
2279                         ppp_recv_unlock(ppp);
2280                         if (ostate) {
2281                                 ocomp->decomp_free(ostate);
2282                                 module_put(ocomp->owner);
2283                         }
2284                         err = 0;
2285                 } else
2286                         module_put(cp->owner);
2287         }
2288
2289  out:
2290         return err;
2291 }
2292
2293 /*
2294  * Look at a CCP packet and update our state accordingly.
2295  * We assume the caller has the xmit or recv path locked.
2296  */
2297 static void
2298 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2299 {
2300         unsigned char *dp;
2301         int len;
2302
2303         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2304                 return; /* no header */
2305         dp = skb->data + 2;
2306
2307         switch (CCP_CODE(dp)) {
2308         case CCP_CONFREQ:
2309
2310                 /* A ConfReq starts negotiation of compression
2311                  * in one direction of transmission,
2312                  * and hence brings it down...but which way?
2313                  *
2314                  * Remember:
2315                  * A ConfReq indicates what the sender would like to receive
2316                  */
2317                 if(inbound)
2318                         /* He is proposing what I should send */
2319                         ppp->xstate &= ~SC_COMP_RUN;
2320                 else
2321                         /* I am proposing to what he should send */
2322                         ppp->rstate &= ~SC_DECOMP_RUN;
2323
2324                 break;
2325
2326         case CCP_TERMREQ:
2327         case CCP_TERMACK:
2328                 /*
2329                  * CCP is going down, both directions of transmission
2330                  */
2331                 ppp->rstate &= ~SC_DECOMP_RUN;
2332                 ppp->xstate &= ~SC_COMP_RUN;
2333                 break;
2334
2335         case CCP_CONFACK:
2336                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2337                         break;
2338                 len = CCP_LENGTH(dp);
2339                 if (!pskb_may_pull(skb, len + 2))
2340                         return;         /* too short */
2341                 dp += CCP_HDRLEN;
2342                 len -= CCP_HDRLEN;
2343                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2344                         break;
2345                 if (inbound) {
2346                         /* we will start receiving compressed packets */
2347                         if (!ppp->rc_state)
2348                                 break;
2349                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2350                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2351                                 ppp->rstate |= SC_DECOMP_RUN;
2352                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2353                         }
2354                 } else {
2355                         /* we will soon start sending compressed packets */
2356                         if (!ppp->xc_state)
2357                                 break;
2358                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2359                                         ppp->file.index, 0, ppp->debug))
2360                                 ppp->xstate |= SC_COMP_RUN;
2361                 }
2362                 break;
2363
2364         case CCP_RESETACK:
2365                 /* reset the [de]compressor */
2366                 if ((ppp->flags & SC_CCP_UP) == 0)
2367                         break;
2368                 if (inbound) {
2369                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2370                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2371                                 ppp->rstate &= ~SC_DC_ERROR;
2372                         }
2373                 } else {
2374                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2375                                 ppp->xcomp->comp_reset(ppp->xc_state);
2376                 }
2377                 break;
2378         }
2379 }
2380
2381 /* Free up compression resources. */
2382 static void
2383 ppp_ccp_closed(struct ppp *ppp)
2384 {
2385         void *xstate, *rstate;
2386         struct compressor *xcomp, *rcomp;
2387
2388         ppp_lock(ppp);
2389         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2390         ppp->xstate = 0;
2391         xcomp = ppp->xcomp;
2392         xstate = ppp->xc_state;
2393         ppp->xc_state = NULL;
2394         ppp->rstate = 0;
2395         rcomp = ppp->rcomp;
2396         rstate = ppp->rc_state;
2397         ppp->rc_state = NULL;
2398         ppp_unlock(ppp);
2399
2400         if (xstate) {
2401                 xcomp->comp_free(xstate);
2402                 module_put(xcomp->owner);
2403         }
2404         if (rstate) {
2405                 rcomp->decomp_free(rstate);
2406                 module_put(rcomp->owner);
2407         }
2408 }
2409
2410 /* List of compressors. */
2411 static LIST_HEAD(compressor_list);
2412 static DEFINE_SPINLOCK(compressor_list_lock);
2413
2414 struct compressor_entry {
2415         struct list_head list;
2416         struct compressor *comp;
2417 };
2418
2419 static struct compressor_entry *
2420 find_comp_entry(int proto)
2421 {
2422         struct compressor_entry *ce;
2423
2424         list_for_each_entry(ce, &compressor_list, list) {
2425                 if (ce->comp->compress_proto == proto)
2426                         return ce;
2427         }
2428         return NULL;
2429 }
2430
2431 /* Register a compressor */
2432 int
2433 ppp_register_compressor(struct compressor *cp)
2434 {
2435         struct compressor_entry *ce;
2436         int ret;
2437         spin_lock(&compressor_list_lock);
2438         ret = -EEXIST;
2439         if (find_comp_entry(cp->compress_proto))
2440                 goto out;
2441         ret = -ENOMEM;
2442         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2443         if (!ce)
2444                 goto out;
2445         ret = 0;
2446         ce->comp = cp;
2447         list_add(&ce->list, &compressor_list);
2448  out:
2449         spin_unlock(&compressor_list_lock);
2450         return ret;
2451 }
2452
2453 /* Unregister a compressor */
2454 void
2455 ppp_unregister_compressor(struct compressor *cp)
2456 {
2457         struct compressor_entry *ce;
2458
2459         spin_lock(&compressor_list_lock);
2460         ce = find_comp_entry(cp->compress_proto);
2461         if (ce && ce->comp == cp) {
2462                 list_del(&ce->list);
2463                 kfree(ce);
2464         }
2465         spin_unlock(&compressor_list_lock);
2466 }
2467
2468 /* Find a compressor. */
2469 static struct compressor *
2470 find_compressor(int type)
2471 {
2472         struct compressor_entry *ce;
2473         struct compressor *cp = NULL;
2474
2475         spin_lock(&compressor_list_lock);
2476         ce = find_comp_entry(type);
2477         if (ce) {
2478                 cp = ce->comp;
2479                 if (!try_module_get(cp->owner))
2480                         cp = NULL;
2481         }
2482         spin_unlock(&compressor_list_lock);
2483         return cp;
2484 }
2485
2486 /*
2487  * Miscelleneous stuff.
2488  */
2489
2490 static void
2491 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2492 {
2493         struct slcompress *vj = ppp->vj;
2494
2495         memset(st, 0, sizeof(*st));
2496         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2497         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2498         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2499         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2500         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2501         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2502         if (!vj)
2503                 return;
2504         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2505         st->vj.vjs_compressed = vj->sls_o_compressed;
2506         st->vj.vjs_searches = vj->sls_o_searches;
2507         st->vj.vjs_misses = vj->sls_o_misses;
2508         st->vj.vjs_errorin = vj->sls_i_error;
2509         st->vj.vjs_tossed = vj->sls_i_tossed;
2510         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2511         st->vj.vjs_compressedin = vj->sls_i_compressed;
2512 }
2513
2514 /*
2515  * Stuff for handling the lists of ppp units and channels
2516  * and for initialization.
2517  */
2518
2519 /*
2520  * Create a new ppp interface unit.  Fails if it can't allocate memory
2521  * or if there is already a unit with the requested number.
2522  * unit == -1 means allocate a new number.
2523  */
2524 static struct ppp *
2525 ppp_create_interface(struct net *net, int unit, int *retp)
2526 {
2527         struct ppp *ppp;
2528         struct ppp_net *pn;
2529         struct net_device *dev = NULL;
2530         int ret = -ENOMEM;
2531         int i;
2532
2533         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2534         if (!dev)
2535                 goto out1;
2536
2537         pn = ppp_pernet(net);
2538
2539         ppp = netdev_priv(dev);
2540         ppp->dev = dev;
2541         ppp->mru = PPP_MRU;
2542         init_ppp_file(&ppp->file, INTERFACE);
2543         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2544         for (i = 0; i < NUM_NP; ++i)
2545                 ppp->npmode[i] = NPMODE_PASS;
2546         INIT_LIST_HEAD(&ppp->channels);
2547         spin_lock_init(&ppp->rlock);
2548         spin_lock_init(&ppp->wlock);
2549 #ifdef CONFIG_PPP_MULTILINK
2550         ppp->minseq = -1;
2551         skb_queue_head_init(&ppp->mrq);
2552 #endif /* CONFIG_PPP_MULTILINK */
2553
2554         /*
2555          * drum roll: don't forget to set
2556          * the net device is belong to
2557          */
2558         dev_net_set(dev, net);
2559
2560         ret = -EEXIST;
2561         mutex_lock(&pn->all_ppp_mutex);
2562
2563         if (unit < 0) {
2564                 unit = unit_get(&pn->units_idr, ppp);
2565                 if (unit < 0) {
2566                         *retp = unit;
2567                         goto out2;
2568                 }
2569         } else {
2570                 if (unit_find(&pn->units_idr, unit))
2571                         goto out2; /* unit already exists */
2572                 /*
2573                  * if caller need a specified unit number
2574                  * lets try to satisfy him, otherwise --
2575                  * he should better ask us for new unit number
2576                  *
2577                  * NOTE: yes I know that returning EEXIST it's not
2578                  * fair but at least pppd will ask us to allocate
2579                  * new unit in this case so user is happy :)
2580                  */
2581                 unit = unit_set(&pn->units_idr, ppp, unit);
2582                 if (unit < 0)
2583                         goto out2;
2584         }
2585
2586         /* Initialize the new ppp unit */
2587         ppp->file.index = unit;
2588         sprintf(dev->name, "ppp%d", unit);
2589
2590         ret = register_netdev(dev);
2591         if (ret != 0) {
2592                 unit_put(&pn->units_idr, unit);
2593                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2594                        dev->name, ret);
2595                 goto out2;
2596         }
2597
2598         ppp->ppp_net = net;
2599
2600         atomic_inc(&ppp_unit_count);
2601         mutex_unlock(&pn->all_ppp_mutex);
2602
2603         *retp = 0;
2604         return ppp;
2605
2606 out2:
2607         mutex_unlock(&pn->all_ppp_mutex);
2608         free_netdev(dev);
2609 out1:
2610         *retp = ret;
2611         return NULL;
2612 }
2613
2614 /*
2615  * Initialize a ppp_file structure.
2616  */
2617 static void
2618 init_ppp_file(struct ppp_file *pf, int kind)
2619 {
2620         pf->kind = kind;
2621         skb_queue_head_init(&pf->xq);
2622         skb_queue_head_init(&pf->rq);
2623         atomic_set(&pf->refcnt, 1);
2624         init_waitqueue_head(&pf->rwait);
2625 }
2626
2627 /*
2628  * Take down a ppp interface unit - called when the owning file
2629  * (the one that created the unit) is closed or detached.
2630  */
2631 static void ppp_shutdown_interface(struct ppp *ppp)
2632 {
2633         struct ppp_net *pn;
2634
2635         pn = ppp_pernet(ppp->ppp_net);
2636         mutex_lock(&pn->all_ppp_mutex);
2637
2638         /* This will call dev_close() for us. */
2639         ppp_lock(ppp);
2640         if (!ppp->closing) {
2641                 ppp->closing = 1;
2642                 ppp_unlock(ppp);
2643                 unregister_netdev(ppp->dev);
2644         } else
2645                 ppp_unlock(ppp);
2646
2647         unit_put(&pn->units_idr, ppp->file.index);
2648         ppp->file.dead = 1;
2649         ppp->owner = NULL;
2650         wake_up_interruptible(&ppp->file.rwait);
2651
2652         mutex_unlock(&pn->all_ppp_mutex);
2653 }
2654
2655 /*
2656  * Free the memory used by a ppp unit.  This is only called once
2657  * there are no channels connected to the unit and no file structs
2658  * that reference the unit.
2659  */
2660 static void ppp_destroy_interface(struct ppp *ppp)
2661 {
2662         atomic_dec(&ppp_unit_count);
2663
2664         if (!ppp->file.dead || ppp->n_channels) {
2665                 /* "can't happen" */
2666                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2667                        "n_channels=%d !\n", ppp, ppp->file.dead,
2668                        ppp->n_channels);
2669                 return;
2670         }
2671
2672         ppp_ccp_closed(ppp);
2673         if (ppp->vj) {
2674                 slhc_free(ppp->vj);
2675                 ppp->vj = NULL;
2676         }
2677         skb_queue_purge(&ppp->file.xq);
2678         skb_queue_purge(&ppp->file.rq);
2679 #ifdef CONFIG_PPP_MULTILINK
2680         skb_queue_purge(&ppp->mrq);
2681 #endif /* CONFIG_PPP_MULTILINK */
2682 #ifdef CONFIG_PPP_FILTER
2683         kfree(ppp->pass_filter);
2684         ppp->pass_filter = NULL;
2685         kfree(ppp->active_filter);
2686         ppp->active_filter = NULL;
2687 #endif /* CONFIG_PPP_FILTER */
2688
2689         kfree_skb(ppp->xmit_pending);
2690
2691         free_netdev(ppp->dev);
2692 }
2693
2694 /*
2695  * Locate an existing ppp unit.
2696  * The caller should have locked the all_ppp_mutex.
2697  */
2698 static struct ppp *
2699 ppp_find_unit(struct ppp_net *pn, int unit)
2700 {
2701         return unit_find(&pn->units_idr, unit);
2702 }
2703
2704 /*
2705  * Locate an existing ppp channel.
2706  * The caller should have locked the all_channels_lock.
2707  * First we look in the new_channels list, then in the
2708  * all_channels list.  If found in the new_channels list,
2709  * we move it to the all_channels list.  This is for speed
2710  * when we have a lot of channels in use.
2711  */
2712 static struct channel *
2713 ppp_find_channel(struct ppp_net *pn, int unit)
2714 {
2715         struct channel *pch;
2716
2717         list_for_each_entry(pch, &pn->new_channels, list) {
2718                 if (pch->file.index == unit) {
2719                         list_move(&pch->list, &pn->all_channels);
2720                         return pch;
2721                 }
2722         }
2723
2724         list_for_each_entry(pch, &pn->all_channels, list) {
2725                 if (pch->file.index == unit)
2726                         return pch;
2727         }
2728
2729         return NULL;
2730 }
2731
2732 /*
2733  * Connect a PPP channel to a PPP interface unit.
2734  */
2735 static int
2736 ppp_connect_channel(struct channel *pch, int unit)
2737 {
2738         struct ppp *ppp;
2739         struct ppp_net *pn;
2740         int ret = -ENXIO;
2741         int hdrlen;
2742
2743         pn = ppp_pernet(pch->chan_net);
2744
2745         mutex_lock(&pn->all_ppp_mutex);
2746         ppp = ppp_find_unit(pn, unit);
2747         if (!ppp)
2748                 goto out;
2749         write_lock_bh(&pch->upl);
2750         ret = -EINVAL;
2751         if (pch->ppp)
2752                 goto outl;
2753
2754         ppp_lock(ppp);
2755         if (pch->file.hdrlen > ppp->file.hdrlen)
2756                 ppp->file.hdrlen = pch->file.hdrlen;
2757         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2758         if (hdrlen > ppp->dev->hard_header_len)
2759                 ppp->dev->hard_header_len = hdrlen;
2760         list_add_tail(&pch->clist, &ppp->channels);
2761         ++ppp->n_channels;
2762         pch->ppp = ppp;
2763         atomic_inc(&ppp->file.refcnt);
2764         ppp_unlock(ppp);
2765         ret = 0;
2766
2767  outl:
2768         write_unlock_bh(&pch->upl);
2769  out:
2770         mutex_unlock(&pn->all_ppp_mutex);
2771         return ret;
2772 }
2773
2774 /*
2775  * Disconnect a channel from its ppp unit.
2776  */
2777 static int
2778 ppp_disconnect_channel(struct channel *pch)
2779 {
2780         struct ppp *ppp;
2781         int err = -EINVAL;
2782
2783         write_lock_bh(&pch->upl);
2784         ppp = pch->ppp;
2785         pch->ppp = NULL;
2786         write_unlock_bh(&pch->upl);
2787         if (ppp) {
2788                 /* remove it from the ppp unit's list */
2789                 ppp_lock(ppp);
2790                 list_del(&pch->clist);
2791                 if (--ppp->n_channels == 0)
2792                         wake_up_interruptible(&ppp->file.rwait);
2793                 ppp_unlock(ppp);
2794                 if (atomic_dec_and_test(&ppp->file.refcnt))
2795                         ppp_destroy_interface(ppp);
2796                 err = 0;
2797         }
2798         return err;
2799 }
2800
2801 /*
2802  * Free up the resources used by a ppp channel.
2803  */
2804 static void ppp_destroy_channel(struct channel *pch)
2805 {
2806         atomic_dec(&channel_count);
2807
2808         if (!pch->file.dead) {
2809                 /* "can't happen" */
2810                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2811                        pch);
2812                 return;
2813         }
2814         skb_queue_purge(&pch->file.xq);
2815         skb_queue_purge(&pch->file.rq);
2816         kfree(pch);
2817 }
2818
2819 static void __exit ppp_cleanup(void)
2820 {
2821         /* should never happen */
2822         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2823                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2824         unregister_chrdev(PPP_MAJOR, "ppp");
2825         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2826         class_destroy(ppp_class);
2827         unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
2828 }
2829
2830 /*
2831  * Units handling. Caller must protect concurrent access
2832  * by holding all_ppp_mutex
2833  */
2834
2835 /* associate pointer with specified number */
2836 static int unit_set(struct idr *p, void *ptr, int n)
2837 {
2838         int unit, err;
2839
2840 again:
2841         if (!idr_pre_get(p, GFP_KERNEL)) {
2842                 printk(KERN_ERR "PPP: No free memory for idr\n");
2843                 return -ENOMEM;
2844         }
2845
2846         err = idr_get_new_above(p, ptr, n, &unit);
2847         if (err == -EAGAIN)
2848                 goto again;
2849
2850         if (unit != n) {
2851                 idr_remove(p, unit);
2852                 return -EINVAL;
2853         }
2854
2855         return unit;
2856 }
2857
2858 /* get new free unit number and associate pointer with it */
2859 static int unit_get(struct idr *p, void *ptr)
2860 {
2861         int unit, err;
2862
2863 again:
2864         if (!idr_pre_get(p, GFP_KERNEL)) {
2865                 printk(KERN_ERR "PPP: No free memory for idr\n");
2866                 return -ENOMEM;
2867         }
2868
2869         err = idr_get_new_above(p, ptr, 0, &unit);
2870         if (err == -EAGAIN)
2871                 goto again;
2872
2873         return unit;
2874 }
2875
2876 /* put unit number back to a pool */
2877 static void unit_put(struct idr *p, int n)
2878 {
2879         idr_remove(p, n);
2880 }
2881
2882 /* get pointer associated with the number */
2883 static void *unit_find(struct idr *p, int n)
2884 {
2885         return idr_find(p, n);
2886 }
2887
2888 /* Module/initialization stuff */
2889
2890 module_init(ppp_init);
2891 module_exit(ppp_cleanup);
2892
2893 EXPORT_SYMBOL(ppp_register_net_channel);
2894 EXPORT_SYMBOL(ppp_register_channel);
2895 EXPORT_SYMBOL(ppp_unregister_channel);
2896 EXPORT_SYMBOL(ppp_channel_index);
2897 EXPORT_SYMBOL(ppp_unit_number);
2898 EXPORT_SYMBOL(ppp_input);
2899 EXPORT_SYMBOL(ppp_input_error);
2900 EXPORT_SYMBOL(ppp_output_wakeup);
2901 EXPORT_SYMBOL(ppp_register_compressor);
2902 EXPORT_SYMBOL(ppp_unregister_compressor);
2903 MODULE_LICENSE("GPL");
2904 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2905 MODULE_ALIAS("/dev/ppp");