425ff5b117f1c3e2da4338ee44e9dbce25f318fe
[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/config.h>
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/kmod.h>
29 #include <linux/init.h>
30 #include <linux/list.h>
31 #include <linux/netdevice.h>
32 #include <linux/poll.h>
33 #include <linux/ppp_defs.h>
34 #include <linux/filter.h>
35 #include <linux/if_ppp.h>
36 #include <linux/ppp_channel.h>
37 #include <linux/ppp-comp.h>
38 #include <linux/skbuff.h>
39 #include <linux/rtnetlink.h>
40 #include <linux/if_arp.h>
41 #include <linux/ip.h>
42 #include <linux/tcp.h>
43 #include <linux/spinlock.h>
44 #include <linux/smp_lock.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 #define PPP_VERSION     "2.4.2"
53
54 /*
55  * Network protocols we support.
56  */
57 #define NP_IP   0               /* Internet Protocol V4 */
58 #define NP_IPV6 1               /* Internet Protocol V6 */
59 #define NP_IPX  2               /* IPX protocol */
60 #define NP_AT   3               /* Appletalk protocol */
61 #define NP_MPLS_UC 4            /* MPLS unicast */
62 #define NP_MPLS_MC 5            /* MPLS multicast */
63 #define NUM_NP  6               /* Number of NPs. */
64
65 #define MPHDRLEN        6       /* multilink protocol header length */
66 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
67 #define MIN_FRAG_SIZE   64
68
69 /*
70  * An instance of /dev/ppp can be associated with either a ppp
71  * interface unit or a ppp channel.  In both cases, file->private_data
72  * points to one of these.
73  */
74 struct ppp_file {
75         enum {
76                 INTERFACE=1, CHANNEL
77         }               kind;
78         struct sk_buff_head xq;         /* pppd transmit queue */
79         struct sk_buff_head rq;         /* receive queue for pppd */
80         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
81         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
82         int             hdrlen;         /* space to leave for headers */
83         int             index;          /* interface unit / channel number */
84         int             dead;           /* unit/channel has been shut down */
85 };
86
87 #define PF_TO_X(pf, X)          ((X *)((char *)(pf) - offsetof(X, file)))
88
89 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
90 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
91
92 #define ROUNDUP(n, x)           (((n) + (x) - 1) / (x))
93
94 /*
95  * Data structure describing one ppp unit.
96  * A ppp unit corresponds to a ppp network interface device
97  * and represents a multilink bundle.
98  * It can have 0 or more ppp channels connected to it.
99  */
100 struct ppp {
101         struct ppp_file file;           /* stuff for read/write/poll 0 */
102         struct file     *owner;         /* file that owns this unit 48 */
103         struct list_head channels;      /* list of attached channels 4c */
104         int             n_channels;     /* how many channels are attached 54 */
105         spinlock_t      rlock;          /* lock for receive side 58 */
106         spinlock_t      wlock;          /* lock for transmit side 5c */
107         int             mru;            /* max receive unit 60 */
108         unsigned int    flags;          /* control bits 64 */
109         unsigned int    xstate;         /* transmit state bits 68 */
110         unsigned int    rstate;         /* receive state bits 6c */
111         int             debug;          /* debug flags 70 */
112         struct slcompress *vj;          /* state for VJ header compression */
113         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
114         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
115         struct compressor *xcomp;       /* transmit packet compressor 8c */
116         void            *xc_state;      /* its internal state 90 */
117         struct compressor *rcomp;       /* receive decompressor 94 */
118         void            *rc_state;      /* its internal state 98 */
119         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
120         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
121         struct net_device *dev;         /* network interface device a4 */
122 #ifdef CONFIG_PPP_MULTILINK
123         int             nxchan;         /* next channel to send something on */
124         u32             nxseq;          /* next sequence number to send */
125         int             mrru;           /* MP: max reconst. receive unit */
126         u32             nextseq;        /* MP: seq no of next packet */
127         u32             minseq;         /* MP: min of most recent seqnos */
128         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
129 #endif /* CONFIG_PPP_MULTILINK */
130         struct net_device_stats stats;  /* statistics */
131 #ifdef CONFIG_PPP_FILTER
132         struct sock_filter *pass_filter;        /* filter for packets to pass */
133         struct sock_filter *active_filter;/* filter for pkts to reset idle */
134         unsigned pass_len, active_len;
135 #endif /* CONFIG_PPP_FILTER */
136 };
137
138 /*
139  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
140  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
141  * SC_MUST_COMP
142  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
143  * Bits in xstate: SC_COMP_RUN
144  */
145 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
146                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
147                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
148
149 /*
150  * Private data structure for each channel.
151  * This includes the data structure used for multilink.
152  */
153 struct channel {
154         struct ppp_file file;           /* stuff for read/write/poll */
155         struct list_head list;          /* link in all/new_channels list */
156         struct ppp_channel *chan;       /* public channel data structure */
157         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
158         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
159         struct ppp      *ppp;           /* ppp unit we're connected to */
160         struct list_head clist;         /* link in list of channels per unit */
161         rwlock_t        upl;            /* protects `ppp' */
162 #ifdef CONFIG_PPP_MULTILINK
163         u8              avail;          /* flag used in multilink stuff */
164         u8              had_frag;       /* >= 1 fragments have been sent */
165         u32             lastseq;        /* MP: last sequence # received */
166 #endif /* CONFIG_PPP_MULTILINK */
167 };
168
169 /*
170  * SMP locking issues:
171  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
172  * list and the ppp.n_channels field, you need to take both locks
173  * before you modify them.
174  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
175  * channel.downl.
176  */
177
178 /*
179  * A cardmap represents a mapping from unsigned integers to pointers,
180  * and provides a fast "find lowest unused number" operation.
181  * It uses a broad (32-way) tree with a bitmap at each level.
182  * It is designed to be space-efficient for small numbers of entries
183  * and time-efficient for large numbers of entries.
184  */
185 #define CARDMAP_ORDER   5
186 #define CARDMAP_WIDTH   (1U << CARDMAP_ORDER)
187 #define CARDMAP_MASK    (CARDMAP_WIDTH - 1)
188
189 struct cardmap {
190         int shift;
191         unsigned long inuse;
192         struct cardmap *parent;
193         void *ptr[CARDMAP_WIDTH];
194 };
195 static void *cardmap_get(struct cardmap *map, unsigned int nr);
196 static void cardmap_set(struct cardmap **map, unsigned int nr, void *ptr);
197 static unsigned int cardmap_find_first_free(struct cardmap *map);
198 static void cardmap_destroy(struct cardmap **map);
199
200 /*
201  * all_ppp_mutex protects the all_ppp_units mapping.
202  * It also ensures that finding a ppp unit in the all_ppp_units map
203  * and updating its file.refcnt field is atomic.
204  */
205 static DEFINE_MUTEX(all_ppp_mutex);
206 static struct cardmap *all_ppp_units;
207 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
208
209 /*
210  * all_channels_lock protects all_channels and last_channel_index,
211  * and the atomicity of find a channel and updating its file.refcnt
212  * field.
213  */
214 static DEFINE_SPINLOCK(all_channels_lock);
215 static LIST_HEAD(all_channels);
216 static LIST_HEAD(new_channels);
217 static int last_channel_index;
218 static atomic_t channel_count = ATOMIC_INIT(0);
219
220 /* Get the PPP protocol number from a skb */
221 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
222
223 /* We limit the length of ppp->file.rq to this (arbitrary) value */
224 #define PPP_MAX_RQLEN   32
225
226 /*
227  * Maximum number of multilink fragments queued up.
228  * This has to be large enough to cope with the maximum latency of
229  * the slowest channel relative to the others.  Strictly it should
230  * depend on the number of channels and their characteristics.
231  */
232 #define PPP_MP_MAX_QLEN 128
233
234 /* Multilink header bits. */
235 #define B       0x80            /* this fragment begins a packet */
236 #define E       0x40            /* this fragment ends a packet */
237
238 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
239 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
240 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
241
242 /* Prototypes. */
243 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
244                                 unsigned int cmd, unsigned long arg);
245 static void ppp_xmit_process(struct ppp *ppp);
246 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
247 static void ppp_push(struct ppp *ppp);
248 static void ppp_channel_push(struct channel *pch);
249 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
250                               struct channel *pch);
251 static void ppp_receive_error(struct ppp *ppp);
252 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
253 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
254                                             struct sk_buff *skb);
255 #ifdef CONFIG_PPP_MULTILINK
256 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
257                                 struct channel *pch);
258 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
259 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
260 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
261 #endif /* CONFIG_PPP_MULTILINK */
262 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
263 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
264 static void ppp_ccp_closed(struct ppp *ppp);
265 static struct compressor *find_compressor(int type);
266 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
267 static struct ppp *ppp_create_interface(int unit, int *retp);
268 static void init_ppp_file(struct ppp_file *pf, int kind);
269 static void ppp_shutdown_interface(struct ppp *ppp);
270 static void ppp_destroy_interface(struct ppp *ppp);
271 static struct ppp *ppp_find_unit(int unit);
272 static struct channel *ppp_find_channel(int unit);
273 static int ppp_connect_channel(struct channel *pch, int unit);
274 static int ppp_disconnect_channel(struct channel *pch);
275 static void ppp_destroy_channel(struct channel *pch);
276
277 static struct class *ppp_class;
278
279 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
280 static inline int proto_to_npindex(int proto)
281 {
282         switch (proto) {
283         case PPP_IP:
284                 return NP_IP;
285         case PPP_IPV6:
286                 return NP_IPV6;
287         case PPP_IPX:
288                 return NP_IPX;
289         case PPP_AT:
290                 return NP_AT;
291         case PPP_MPLS_UC:
292                 return NP_MPLS_UC;
293         case PPP_MPLS_MC:
294                 return NP_MPLS_MC;
295         }
296         return -EINVAL;
297 }
298
299 /* Translates an NP index into a PPP protocol number */
300 static const int npindex_to_proto[NUM_NP] = {
301         PPP_IP,
302         PPP_IPV6,
303         PPP_IPX,
304         PPP_AT,
305         PPP_MPLS_UC,
306         PPP_MPLS_MC,
307 };
308         
309 /* Translates an ethertype into an NP index */
310 static inline int ethertype_to_npindex(int ethertype)
311 {
312         switch (ethertype) {
313         case ETH_P_IP:
314                 return NP_IP;
315         case ETH_P_IPV6:
316                 return NP_IPV6;
317         case ETH_P_IPX:
318                 return NP_IPX;
319         case ETH_P_PPPTALK:
320         case ETH_P_ATALK:
321                 return NP_AT;
322         case ETH_P_MPLS_UC:
323                 return NP_MPLS_UC;
324         case ETH_P_MPLS_MC:
325                 return NP_MPLS_MC;
326         }
327         return -1;
328 }
329
330 /* Translates an NP index into an ethertype */
331 static const int npindex_to_ethertype[NUM_NP] = {
332         ETH_P_IP,
333         ETH_P_IPV6,
334         ETH_P_IPX,
335         ETH_P_PPPTALK,
336         ETH_P_MPLS_UC,
337         ETH_P_MPLS_MC,
338 };
339
340 /*
341  * Locking shorthand.
342  */
343 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
344 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
345 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
346 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
347 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
348                                      ppp_recv_lock(ppp); } while (0)
349 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
350                                      ppp_xmit_unlock(ppp); } while (0)
351
352 /*
353  * /dev/ppp device routines.
354  * The /dev/ppp device is used by pppd to control the ppp unit.
355  * It supports the read, write, ioctl and poll functions.
356  * Open instances of /dev/ppp can be in one of three states:
357  * unattached, attached to a ppp unit, or attached to a ppp channel.
358  */
359 static int ppp_open(struct inode *inode, struct file *file)
360 {
361         /*
362          * This could (should?) be enforced by the permissions on /dev/ppp.
363          */
364         if (!capable(CAP_NET_ADMIN))
365                 return -EPERM;
366         return 0;
367 }
368
369 static int ppp_release(struct inode *inode, struct file *file)
370 {
371         struct ppp_file *pf = file->private_data;
372         struct ppp *ppp;
373
374         if (pf != 0) {
375                 file->private_data = NULL;
376                 if (pf->kind == INTERFACE) {
377                         ppp = PF_TO_PPP(pf);
378                         if (file == ppp->owner)
379                                 ppp_shutdown_interface(ppp);
380                 }
381                 if (atomic_dec_and_test(&pf->refcnt)) {
382                         switch (pf->kind) {
383                         case INTERFACE:
384                                 ppp_destroy_interface(PF_TO_PPP(pf));
385                                 break;
386                         case CHANNEL:
387                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
388                                 break;
389                         }
390                 }
391         }
392         return 0;
393 }
394
395 static ssize_t ppp_read(struct file *file, char __user *buf,
396                         size_t count, loff_t *ppos)
397 {
398         struct ppp_file *pf = file->private_data;
399         DECLARE_WAITQUEUE(wait, current);
400         ssize_t ret;
401         struct sk_buff *skb = NULL;
402
403         ret = count;
404
405         if (pf == 0)
406                 return -ENXIO;
407         add_wait_queue(&pf->rwait, &wait);
408         for (;;) {
409                 set_current_state(TASK_INTERRUPTIBLE);
410                 skb = skb_dequeue(&pf->rq);
411                 if (skb)
412                         break;
413                 ret = 0;
414                 if (pf->dead)
415                         break;
416                 if (pf->kind == INTERFACE) {
417                         /*
418                          * Return 0 (EOF) on an interface that has no
419                          * channels connected, unless it is looping
420                          * network traffic (demand mode).
421                          */
422                         struct ppp *ppp = PF_TO_PPP(pf);
423                         if (ppp->n_channels == 0
424                             && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
425                                 break;
426                 }
427                 ret = -EAGAIN;
428                 if (file->f_flags & O_NONBLOCK)
429                         break;
430                 ret = -ERESTARTSYS;
431                 if (signal_pending(current))
432                         break;
433                 schedule();
434         }
435         set_current_state(TASK_RUNNING);
436         remove_wait_queue(&pf->rwait, &wait);
437
438         if (skb == 0)
439                 goto out;
440
441         ret = -EOVERFLOW;
442         if (skb->len > count)
443                 goto outf;
444         ret = -EFAULT;
445         if (copy_to_user(buf, skb->data, skb->len))
446                 goto outf;
447         ret = skb->len;
448
449  outf:
450         kfree_skb(skb);
451  out:
452         return ret;
453 }
454
455 static ssize_t ppp_write(struct file *file, const char __user *buf,
456                          size_t count, loff_t *ppos)
457 {
458         struct ppp_file *pf = file->private_data;
459         struct sk_buff *skb;
460         ssize_t ret;
461
462         if (pf == 0)
463                 return -ENXIO;
464         ret = -ENOMEM;
465         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
466         if (skb == 0)
467                 goto out;
468         skb_reserve(skb, pf->hdrlen);
469         ret = -EFAULT;
470         if (copy_from_user(skb_put(skb, count), buf, count)) {
471                 kfree_skb(skb);
472                 goto out;
473         }
474
475         skb_queue_tail(&pf->xq, skb);
476
477         switch (pf->kind) {
478         case INTERFACE:
479                 ppp_xmit_process(PF_TO_PPP(pf));
480                 break;
481         case CHANNEL:
482                 ppp_channel_push(PF_TO_CHANNEL(pf));
483                 break;
484         }
485
486         ret = count;
487
488  out:
489         return ret;
490 }
491
492 /* No kernel lock - fine */
493 static unsigned int ppp_poll(struct file *file, poll_table *wait)
494 {
495         struct ppp_file *pf = file->private_data;
496         unsigned int mask;
497
498         if (pf == 0)
499                 return 0;
500         poll_wait(file, &pf->rwait, wait);
501         mask = POLLOUT | POLLWRNORM;
502         if (skb_peek(&pf->rq) != 0)
503                 mask |= POLLIN | POLLRDNORM;
504         if (pf->dead)
505                 mask |= POLLHUP;
506         else if (pf->kind == INTERFACE) {
507                 /* see comment in ppp_read */
508                 struct ppp *ppp = PF_TO_PPP(pf);
509                 if (ppp->n_channels == 0
510                     && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
511                         mask |= POLLIN | POLLRDNORM;
512         }
513
514         return mask;
515 }
516
517 #ifdef CONFIG_PPP_FILTER
518 static int get_filter(void __user *arg, struct sock_filter **p)
519 {
520         struct sock_fprog uprog;
521         struct sock_filter *code = NULL;
522         int len, err;
523
524         if (copy_from_user(&uprog, arg, sizeof(uprog)))
525                 return -EFAULT;
526
527         if (!uprog.len) {
528                 *p = NULL;
529                 return 0;
530         }
531
532         len = uprog.len * sizeof(struct sock_filter);
533         code = kmalloc(len, GFP_KERNEL);
534         if (code == NULL)
535                 return -ENOMEM;
536
537         if (copy_from_user(code, uprog.filter, len)) {
538                 kfree(code);
539                 return -EFAULT;
540         }
541
542         err = sk_chk_filter(code, uprog.len);
543         if (err) {
544                 kfree(code);
545                 return err;
546         }
547
548         *p = code;
549         return uprog.len;
550 }
551 #endif /* CONFIG_PPP_FILTER */
552
553 static int ppp_ioctl(struct inode *inode, struct file *file,
554                      unsigned int cmd, unsigned long arg)
555 {
556         struct ppp_file *pf = file->private_data;
557         struct ppp *ppp;
558         int err = -EFAULT, val, val2, i;
559         struct ppp_idle idle;
560         struct npioctl npi;
561         int unit, cflags;
562         struct slcompress *vj;
563         void __user *argp = (void __user *)arg;
564         int __user *p = argp;
565
566         if (pf == 0)
567                 return ppp_unattached_ioctl(pf, file, cmd, arg);
568
569         if (cmd == PPPIOCDETACH) {
570                 /*
571                  * We have to be careful here... if the file descriptor
572                  * has been dup'd, we could have another process in the
573                  * middle of a poll using the same file *, so we had
574                  * better not free the interface data structures -
575                  * instead we fail the ioctl.  Even in this case, we
576                  * shut down the interface if we are the owner of it.
577                  * Actually, we should get rid of PPPIOCDETACH, userland
578                  * (i.e. pppd) could achieve the same effect by closing
579                  * this fd and reopening /dev/ppp.
580                  */
581                 err = -EINVAL;
582                 if (pf->kind == INTERFACE) {
583                         ppp = PF_TO_PPP(pf);
584                         if (file == ppp->owner)
585                                 ppp_shutdown_interface(ppp);
586                 }
587                 if (atomic_read(&file->f_count) <= 2) {
588                         ppp_release(inode, file);
589                         err = 0;
590                 } else
591                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%d\n",
592                                atomic_read(&file->f_count));
593                 return err;
594         }
595
596         if (pf->kind == CHANNEL) {
597                 struct channel *pch = PF_TO_CHANNEL(pf);
598                 struct ppp_channel *chan;
599
600                 switch (cmd) {
601                 case PPPIOCCONNECT:
602                         if (get_user(unit, p))
603                                 break;
604                         err = ppp_connect_channel(pch, unit);
605                         break;
606
607                 case PPPIOCDISCONN:
608                         err = ppp_disconnect_channel(pch);
609                         break;
610
611                 default:
612                         down_read(&pch->chan_sem);
613                         chan = pch->chan;
614                         err = -ENOTTY;
615                         if (chan && chan->ops->ioctl)
616                                 err = chan->ops->ioctl(chan, cmd, arg);
617                         up_read(&pch->chan_sem);
618                 }
619                 return err;
620         }
621
622         if (pf->kind != INTERFACE) {
623                 /* can't happen */
624                 printk(KERN_ERR "PPP: not interface or channel??\n");
625                 return -EINVAL;
626         }
627
628         ppp = PF_TO_PPP(pf);
629         switch (cmd) {
630         case PPPIOCSMRU:
631                 if (get_user(val, p))
632                         break;
633                 ppp->mru = val;
634                 err = 0;
635                 break;
636
637         case PPPIOCSFLAGS:
638                 if (get_user(val, p))
639                         break;
640                 ppp_lock(ppp);
641                 cflags = ppp->flags & ~val;
642                 ppp->flags = val & SC_FLAG_BITS;
643                 ppp_unlock(ppp);
644                 if (cflags & SC_CCP_OPEN)
645                         ppp_ccp_closed(ppp);
646                 err = 0;
647                 break;
648
649         case PPPIOCGFLAGS:
650                 val = ppp->flags | ppp->xstate | ppp->rstate;
651                 if (put_user(val, p))
652                         break;
653                 err = 0;
654                 break;
655
656         case PPPIOCSCOMPRESS:
657                 err = ppp_set_compress(ppp, arg);
658                 break;
659
660         case PPPIOCGUNIT:
661                 if (put_user(ppp->file.index, p))
662                         break;
663                 err = 0;
664                 break;
665
666         case PPPIOCSDEBUG:
667                 if (get_user(val, p))
668                         break;
669                 ppp->debug = val;
670                 err = 0;
671                 break;
672
673         case PPPIOCGDEBUG:
674                 if (put_user(ppp->debug, p))
675                         break;
676                 err = 0;
677                 break;
678
679         case PPPIOCGIDLE:
680                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
681                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
682                 if (copy_to_user(argp, &idle, sizeof(idle)))
683                         break;
684                 err = 0;
685                 break;
686
687         case PPPIOCSMAXCID:
688                 if (get_user(val, p))
689                         break;
690                 val2 = 15;
691                 if ((val >> 16) != 0) {
692                         val2 = val >> 16;
693                         val &= 0xffff;
694                 }
695                 vj = slhc_init(val2+1, val+1);
696                 if (vj == 0) {
697                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
698                         err = -ENOMEM;
699                         break;
700                 }
701                 ppp_lock(ppp);
702                 if (ppp->vj != 0)
703                         slhc_free(ppp->vj);
704                 ppp->vj = vj;
705                 ppp_unlock(ppp);
706                 err = 0;
707                 break;
708
709         case PPPIOCGNPMODE:
710         case PPPIOCSNPMODE:
711                 if (copy_from_user(&npi, argp, sizeof(npi)))
712                         break;
713                 err = proto_to_npindex(npi.protocol);
714                 if (err < 0)
715                         break;
716                 i = err;
717                 if (cmd == PPPIOCGNPMODE) {
718                         err = -EFAULT;
719                         npi.mode = ppp->npmode[i];
720                         if (copy_to_user(argp, &npi, sizeof(npi)))
721                                 break;
722                 } else {
723                         ppp->npmode[i] = npi.mode;
724                         /* we may be able to transmit more packets now (??) */
725                         netif_wake_queue(ppp->dev);
726                 }
727                 err = 0;
728                 break;
729
730 #ifdef CONFIG_PPP_FILTER
731         case PPPIOCSPASS:
732         {
733                 struct sock_filter *code;
734                 err = get_filter(argp, &code);
735                 if (err >= 0) {
736                         ppp_lock(ppp);
737                         kfree(ppp->pass_filter);
738                         ppp->pass_filter = code;
739                         ppp->pass_len = err;
740                         ppp_unlock(ppp);
741                         err = 0;
742                 }
743                 break;
744         }
745         case PPPIOCSACTIVE:
746         {
747                 struct sock_filter *code;
748                 err = get_filter(argp, &code);
749                 if (err >= 0) {
750                         ppp_lock(ppp);
751                         kfree(ppp->active_filter);
752                         ppp->active_filter = code;
753                         ppp->active_len = err;
754                         ppp_unlock(ppp);
755                         err = 0;
756                 }
757                 break;
758         }
759 #endif /* CONFIG_PPP_FILTER */
760
761 #ifdef CONFIG_PPP_MULTILINK
762         case PPPIOCSMRRU:
763                 if (get_user(val, p))
764                         break;
765                 ppp_recv_lock(ppp);
766                 ppp->mrru = val;
767                 ppp_recv_unlock(ppp);
768                 err = 0;
769                 break;
770 #endif /* CONFIG_PPP_MULTILINK */
771
772         default:
773                 err = -ENOTTY;
774         }
775
776         return err;
777 }
778
779 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
780                                 unsigned int cmd, unsigned long arg)
781 {
782         int unit, err = -EFAULT;
783         struct ppp *ppp;
784         struct channel *chan;
785         int __user *p = (int __user *)arg;
786
787         switch (cmd) {
788         case PPPIOCNEWUNIT:
789                 /* Create a new ppp unit */
790                 if (get_user(unit, p))
791                         break;
792                 ppp = ppp_create_interface(unit, &err);
793                 if (ppp == 0)
794                         break;
795                 file->private_data = &ppp->file;
796                 ppp->owner = file;
797                 err = -EFAULT;
798                 if (put_user(ppp->file.index, p))
799                         break;
800                 err = 0;
801                 break;
802
803         case PPPIOCATTACH:
804                 /* Attach to an existing ppp unit */
805                 if (get_user(unit, p))
806                         break;
807                 mutex_lock(&all_ppp_mutex);
808                 err = -ENXIO;
809                 ppp = ppp_find_unit(unit);
810                 if (ppp != 0) {
811                         atomic_inc(&ppp->file.refcnt);
812                         file->private_data = &ppp->file;
813                         err = 0;
814                 }
815                 mutex_unlock(&all_ppp_mutex);
816                 break;
817
818         case PPPIOCATTCHAN:
819                 if (get_user(unit, p))
820                         break;
821                 spin_lock_bh(&all_channels_lock);
822                 err = -ENXIO;
823                 chan = ppp_find_channel(unit);
824                 if (chan != 0) {
825                         atomic_inc(&chan->file.refcnt);
826                         file->private_data = &chan->file;
827                         err = 0;
828                 }
829                 spin_unlock_bh(&all_channels_lock);
830                 break;
831
832         default:
833                 err = -ENOTTY;
834         }
835         return err;
836 }
837
838 static struct file_operations ppp_device_fops = {
839         .owner          = THIS_MODULE,
840         .read           = ppp_read,
841         .write          = ppp_write,
842         .poll           = ppp_poll,
843         .ioctl          = ppp_ioctl,
844         .open           = ppp_open,
845         .release        = ppp_release
846 };
847
848 #define PPP_MAJOR       108
849
850 /* Called at boot time if ppp is compiled into the kernel,
851    or at module load time (from init_module) if compiled as a module. */
852 static int __init ppp_init(void)
853 {
854         int err;
855
856         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
857         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
858         if (!err) {
859                 ppp_class = class_create(THIS_MODULE, "ppp");
860                 if (IS_ERR(ppp_class)) {
861                         err = PTR_ERR(ppp_class);
862                         goto out_chrdev;
863                 }
864                 class_device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
865         }
866
867 out:
868         if (err)
869                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
870         return err;
871
872 out_chrdev:
873         unregister_chrdev(PPP_MAJOR, "ppp");
874         goto out;
875 }
876
877 /*
878  * Network interface unit routines.
879  */
880 static int
881 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
882 {
883         struct ppp *ppp = (struct ppp *) dev->priv;
884         int npi, proto;
885         unsigned char *pp;
886
887         npi = ethertype_to_npindex(ntohs(skb->protocol));
888         if (npi < 0)
889                 goto outf;
890
891         /* Drop, accept or reject the packet */
892         switch (ppp->npmode[npi]) {
893         case NPMODE_PASS:
894                 break;
895         case NPMODE_QUEUE:
896                 /* it would be nice to have a way to tell the network
897                    system to queue this one up for later. */
898                 goto outf;
899         case NPMODE_DROP:
900         case NPMODE_ERROR:
901                 goto outf;
902         }
903
904         /* Put the 2-byte PPP protocol number on the front,
905            making sure there is room for the address and control fields. */
906         if (skb_headroom(skb) < PPP_HDRLEN) {
907                 struct sk_buff *ns;
908
909                 ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);
910                 if (ns == 0)
911                         goto outf;
912                 skb_reserve(ns, dev->hard_header_len);
913                 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
914                 kfree_skb(skb);
915                 skb = ns;
916         }
917         pp = skb_push(skb, 2);
918         proto = npindex_to_proto[npi];
919         pp[0] = proto >> 8;
920         pp[1] = proto;
921
922         netif_stop_queue(dev);
923         skb_queue_tail(&ppp->file.xq, skb);
924         ppp_xmit_process(ppp);
925         return 0;
926
927  outf:
928         kfree_skb(skb);
929         ++ppp->stats.tx_dropped;
930         return 0;
931 }
932
933 static struct net_device_stats *
934 ppp_net_stats(struct net_device *dev)
935 {
936         struct ppp *ppp = (struct ppp *) dev->priv;
937
938         return &ppp->stats;
939 }
940
941 static int
942 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
943 {
944         struct ppp *ppp = dev->priv;
945         int err = -EFAULT;
946         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
947         struct ppp_stats stats;
948         struct ppp_comp_stats cstats;
949         char *vers;
950
951         switch (cmd) {
952         case SIOCGPPPSTATS:
953                 ppp_get_stats(ppp, &stats);
954                 if (copy_to_user(addr, &stats, sizeof(stats)))
955                         break;
956                 err = 0;
957                 break;
958
959         case SIOCGPPPCSTATS:
960                 memset(&cstats, 0, sizeof(cstats));
961                 if (ppp->xc_state != 0)
962                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
963                 if (ppp->rc_state != 0)
964                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
965                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
966                         break;
967                 err = 0;
968                 break;
969
970         case SIOCGPPPVER:
971                 vers = PPP_VERSION;
972                 if (copy_to_user(addr, vers, strlen(vers) + 1))
973                         break;
974                 err = 0;
975                 break;
976
977         default:
978                 err = -EINVAL;
979         }
980
981         return err;
982 }
983
984 static void ppp_setup(struct net_device *dev)
985 {
986         dev->hard_header_len = PPP_HDRLEN;
987         dev->mtu = PPP_MTU;
988         dev->addr_len = 0;
989         dev->tx_queue_len = 3;
990         dev->type = ARPHRD_PPP;
991         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
992 }
993
994 /*
995  * Transmit-side routines.
996  */
997
998 /*
999  * Called to do any work queued up on the transmit side
1000  * that can now be done.
1001  */
1002 static void
1003 ppp_xmit_process(struct ppp *ppp)
1004 {
1005         struct sk_buff *skb;
1006
1007         ppp_xmit_lock(ppp);
1008         if (ppp->dev != 0) {
1009                 ppp_push(ppp);
1010                 while (ppp->xmit_pending == 0
1011                        && (skb = skb_dequeue(&ppp->file.xq)) != 0)
1012                         ppp_send_frame(ppp, skb);
1013                 /* If there's no work left to do, tell the core net
1014                    code that we can accept some more. */
1015                 if (ppp->xmit_pending == 0 && skb_peek(&ppp->file.xq) == 0)
1016                         netif_wake_queue(ppp->dev);
1017         }
1018         ppp_xmit_unlock(ppp);
1019 }
1020
1021 static inline struct sk_buff *
1022 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1023 {
1024         struct sk_buff *new_skb;
1025         int len;
1026         int new_skb_size = ppp->dev->mtu +
1027                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1028         int compressor_skb_size = ppp->dev->mtu +
1029                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1030         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1031         if (!new_skb) {
1032                 if (net_ratelimit())
1033                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1034                 return NULL;
1035         }
1036         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1037                 skb_reserve(new_skb,
1038                             ppp->dev->hard_header_len - PPP_HDRLEN);
1039
1040         /* compressor still expects A/C bytes in hdr */
1041         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1042                                    new_skb->data, skb->len + 2,
1043                                    compressor_skb_size);
1044         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1045                 kfree_skb(skb);
1046                 skb = new_skb;
1047                 skb_put(skb, len);
1048                 skb_pull(skb, 2);       /* pull off A/C bytes */
1049         } else if (len == 0) {
1050                 /* didn't compress, or CCP not up yet */
1051                 kfree_skb(new_skb);
1052                 new_skb = skb;
1053         } else {
1054                 /*
1055                  * (len < 0)
1056                  * MPPE requires that we do not send unencrypted
1057                  * frames.  The compressor will return -1 if we
1058                  * should drop the frame.  We cannot simply test
1059                  * the compress_proto because MPPE and MPPC share
1060                  * the same number.
1061                  */
1062                 if (net_ratelimit())
1063                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1064                 kfree_skb(skb);
1065                 kfree_skb(new_skb);
1066                 new_skb = NULL;
1067         }
1068         return new_skb;
1069 }
1070
1071 /*
1072  * Compress and send a frame.
1073  * The caller should have locked the xmit path,
1074  * and xmit_pending should be 0.
1075  */
1076 static void
1077 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1078 {
1079         int proto = PPP_PROTO(skb);
1080         struct sk_buff *new_skb;
1081         int len;
1082         unsigned char *cp;
1083
1084         if (proto < 0x8000) {
1085 #ifdef CONFIG_PPP_FILTER
1086                 /* check if we should pass this packet */
1087                 /* the filter instructions are constructed assuming
1088                    a four-byte PPP header on each packet */
1089                 *skb_push(skb, 2) = 1;
1090                 if (ppp->pass_filter
1091                     && sk_run_filter(skb, ppp->pass_filter,
1092                                      ppp->pass_len) == 0) {
1093                         if (ppp->debug & 1)
1094                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1095                         kfree_skb(skb);
1096                         return;
1097                 }
1098                 /* if this packet passes the active filter, record the time */
1099                 if (!(ppp->active_filter
1100                       && sk_run_filter(skb, ppp->active_filter,
1101                                        ppp->active_len) == 0))
1102                         ppp->last_xmit = jiffies;
1103                 skb_pull(skb, 2);
1104 #else
1105                 /* for data packets, record the time */
1106                 ppp->last_xmit = jiffies;
1107 #endif /* CONFIG_PPP_FILTER */
1108         }
1109
1110         ++ppp->stats.tx_packets;
1111         ppp->stats.tx_bytes += skb->len - 2;
1112
1113         switch (proto) {
1114         case PPP_IP:
1115                 if (ppp->vj == 0 || (ppp->flags & SC_COMP_TCP) == 0)
1116                         break;
1117                 /* try to do VJ TCP header compression */
1118                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1119                                     GFP_ATOMIC);
1120                 if (new_skb == 0) {
1121                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1122                         goto drop;
1123                 }
1124                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1125                 cp = skb->data + 2;
1126                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1127                                     new_skb->data + 2, &cp,
1128                                     !(ppp->flags & SC_NO_TCP_CCID));
1129                 if (cp == skb->data + 2) {
1130                         /* didn't compress */
1131                         kfree_skb(new_skb);
1132                 } else {
1133                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1134                                 proto = PPP_VJC_COMP;
1135                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1136                         } else {
1137                                 proto = PPP_VJC_UNCOMP;
1138                                 cp[0] = skb->data[2];
1139                         }
1140                         kfree_skb(skb);
1141                         skb = new_skb;
1142                         cp = skb_put(skb, len + 2);
1143                         cp[0] = 0;
1144                         cp[1] = proto;
1145                 }
1146                 break;
1147
1148         case PPP_CCP:
1149                 /* peek at outbound CCP frames */
1150                 ppp_ccp_peek(ppp, skb, 0);
1151                 break;
1152         }
1153
1154         /* try to do packet compression */
1155         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
1156             && proto != PPP_LCP && proto != PPP_CCP) {
1157                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1158                         if (net_ratelimit())
1159                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1160                         goto drop;
1161                 }
1162                 skb = pad_compress_skb(ppp, skb);
1163                 if (!skb)
1164                         goto drop;
1165         }
1166
1167         /*
1168          * If we are waiting for traffic (demand dialling),
1169          * queue it up for pppd to receive.
1170          */
1171         if (ppp->flags & SC_LOOP_TRAFFIC) {
1172                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1173                         goto drop;
1174                 skb_queue_tail(&ppp->file.rq, skb);
1175                 wake_up_interruptible(&ppp->file.rwait);
1176                 return;
1177         }
1178
1179         ppp->xmit_pending = skb;
1180         ppp_push(ppp);
1181         return;
1182
1183  drop:
1184         if (skb)
1185                 kfree_skb(skb);
1186         ++ppp->stats.tx_errors;
1187 }
1188
1189 /*
1190  * Try to send the frame in xmit_pending.
1191  * The caller should have the xmit path locked.
1192  */
1193 static void
1194 ppp_push(struct ppp *ppp)
1195 {
1196         struct list_head *list;
1197         struct channel *pch;
1198         struct sk_buff *skb = ppp->xmit_pending;
1199
1200         if (skb == 0)
1201                 return;
1202
1203         list = &ppp->channels;
1204         if (list_empty(list)) {
1205                 /* nowhere to send the packet, just drop it */
1206                 ppp->xmit_pending = NULL;
1207                 kfree_skb(skb);
1208                 return;
1209         }
1210
1211         if ((ppp->flags & SC_MULTILINK) == 0) {
1212                 /* not doing multilink: send it down the first channel */
1213                 list = list->next;
1214                 pch = list_entry(list, struct channel, clist);
1215
1216                 spin_lock_bh(&pch->downl);
1217                 if (pch->chan) {
1218                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1219                                 ppp->xmit_pending = NULL;
1220                 } else {
1221                         /* channel got unregistered */
1222                         kfree_skb(skb);
1223                         ppp->xmit_pending = NULL;
1224                 }
1225                 spin_unlock_bh(&pch->downl);
1226                 return;
1227         }
1228
1229 #ifdef CONFIG_PPP_MULTILINK
1230         /* Multilink: fragment the packet over as many links
1231            as can take the packet at the moment. */
1232         if (!ppp_mp_explode(ppp, skb))
1233                 return;
1234 #endif /* CONFIG_PPP_MULTILINK */
1235
1236         ppp->xmit_pending = NULL;
1237         kfree_skb(skb);
1238 }
1239
1240 #ifdef CONFIG_PPP_MULTILINK
1241 /*
1242  * Divide a packet to be transmitted into fragments and
1243  * send them out the individual links.
1244  */
1245 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1246 {
1247         int len, fragsize;
1248         int i, bits, hdrlen, mtu;
1249         int flen;
1250         int navail, nfree;
1251         int nbigger;
1252         unsigned char *p, *q;
1253         struct list_head *list;
1254         struct channel *pch;
1255         struct sk_buff *frag;
1256         struct ppp_channel *chan;
1257
1258         nfree = 0;      /* # channels which have no packet already queued */
1259         navail = 0;     /* total # of usable channels (not deregistered) */
1260         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1261         i = 0;
1262         list_for_each_entry(pch, &ppp->channels, clist) {
1263                 navail += pch->avail = (pch->chan != NULL);
1264                 if (pch->avail) {
1265                         if (skb_queue_empty(&pch->file.xq) ||
1266                             !pch->had_frag) {
1267                                 pch->avail = 2;
1268                                 ++nfree;
1269                         }
1270                         if (!pch->had_frag && i < ppp->nxchan)
1271                                 ppp->nxchan = i;
1272                 }
1273                 ++i;
1274         }
1275
1276         /*
1277          * Don't start sending this packet unless at least half of
1278          * the channels are free.  This gives much better TCP
1279          * performance if we have a lot of channels.
1280          */
1281         if (nfree == 0 || nfree < navail / 2)
1282                 return 0;       /* can't take now, leave it in xmit_pending */
1283
1284         /* Do protocol field compression (XXX this should be optional) */
1285         p = skb->data;
1286         len = skb->len;
1287         if (*p == 0) {
1288                 ++p;
1289                 --len;
1290         }
1291
1292         /*
1293          * Decide on fragment size.
1294          * We create a fragment for each free channel regardless of
1295          * how small they are (i.e. even 0 length) in order to minimize
1296          * the time that it will take to detect when a channel drops
1297          * a fragment.
1298          */
1299         fragsize = len;
1300         if (nfree > 1)
1301                 fragsize = ROUNDUP(fragsize, nfree);
1302         /* nbigger channels get fragsize bytes, the rest get fragsize-1,
1303            except if nbigger==0, then they all get fragsize. */
1304         nbigger = len % nfree;
1305
1306         /* skip to the channel after the one we last used
1307            and start at that one */
1308         list = &ppp->channels;
1309         for (i = 0; i < ppp->nxchan; ++i) {
1310                 list = list->next;
1311                 if (list == &ppp->channels) {
1312                         i = 0;
1313                         break;
1314                 }
1315         }
1316
1317         /* create a fragment for each channel */
1318         bits = B;
1319         while (nfree > 0 || len > 0) {
1320                 list = list->next;
1321                 if (list == &ppp->channels) {
1322                         i = 0;
1323                         continue;
1324                 }
1325                 pch = list_entry(list, struct channel, clist);
1326                 ++i;
1327                 if (!pch->avail)
1328                         continue;
1329
1330                 /*
1331                  * Skip this channel if it has a fragment pending already and
1332                  * we haven't given a fragment to all of the free channels.
1333                  */
1334                 if (pch->avail == 1) {
1335                         if (nfree > 0)
1336                                 continue;
1337                 } else {
1338                         --nfree;
1339                         pch->avail = 1;
1340                 }
1341
1342                 /* check the channel's mtu and whether it is still attached. */
1343                 spin_lock_bh(&pch->downl);
1344                 if (pch->chan == NULL) {
1345                         /* can't use this channel, it's being deregistered */
1346                         spin_unlock_bh(&pch->downl);
1347                         pch->avail = 0;
1348                         if (--navail == 0)
1349                                 break;
1350                         continue;
1351                 }
1352
1353                 /*
1354                  * Create a fragment for this channel of
1355                  * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
1356                  * If mtu+2-hdrlen < 4, that is a ridiculously small
1357                  * MTU, so we use mtu = 2 + hdrlen.
1358                  */
1359                 if (fragsize > len)
1360                         fragsize = len;
1361                 flen = fragsize;
1362                 mtu = pch->chan->mtu + 2 - hdrlen;
1363                 if (mtu < 4)
1364                         mtu = 4;
1365                 if (flen > mtu)
1366                         flen = mtu;
1367                 if (flen == len && nfree == 0)
1368                         bits |= E;
1369                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1370                 if (frag == 0)
1371                         goto noskb;
1372                 q = skb_put(frag, flen + hdrlen);
1373
1374                 /* make the MP header */
1375                 q[0] = PPP_MP >> 8;
1376                 q[1] = PPP_MP;
1377                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1378                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1379                         q[3] = ppp->nxseq;
1380                 } else {
1381                         q[2] = bits;
1382                         q[3] = ppp->nxseq >> 16;
1383                         q[4] = ppp->nxseq >> 8;
1384                         q[5] = ppp->nxseq;
1385                 }
1386
1387                 /*
1388                  * Copy the data in.
1389                  * Unfortunately there is a bug in older versions of
1390                  * the Linux PPP multilink reconstruction code where it
1391                  * drops 0-length fragments.  Therefore we make sure the
1392                  * fragment has at least one byte of data.  Any bytes
1393                  * we add in this situation will end up as padding on the
1394                  * end of the reconstructed packet.
1395                  */
1396                 if (flen == 0)
1397                         *skb_put(frag, 1) = 0;
1398                 else
1399                         memcpy(q + hdrlen, p, flen);
1400
1401                 /* try to send it down the channel */
1402                 chan = pch->chan;
1403                 if (!skb_queue_empty(&pch->file.xq) ||
1404                     !chan->ops->start_xmit(chan, frag))
1405                         skb_queue_tail(&pch->file.xq, frag);
1406                 pch->had_frag = 1;
1407                 p += flen;
1408                 len -= flen;
1409                 ++ppp->nxseq;
1410                 bits = 0;
1411                 spin_unlock_bh(&pch->downl);
1412
1413                 if (--nbigger == 0 && fragsize > 0)
1414                         --fragsize;
1415         }
1416         ppp->nxchan = i;
1417
1418         return 1;
1419
1420  noskb:
1421         spin_unlock_bh(&pch->downl);
1422         if (ppp->debug & 1)
1423                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1424         ++ppp->stats.tx_errors;
1425         ++ppp->nxseq;
1426         return 1;       /* abandon the frame */
1427 }
1428 #endif /* CONFIG_PPP_MULTILINK */
1429
1430 /*
1431  * Try to send data out on a channel.
1432  */
1433 static void
1434 ppp_channel_push(struct channel *pch)
1435 {
1436         struct sk_buff *skb;
1437         struct ppp *ppp;
1438
1439         spin_lock_bh(&pch->downl);
1440         if (pch->chan != 0) {
1441                 while (!skb_queue_empty(&pch->file.xq)) {
1442                         skb = skb_dequeue(&pch->file.xq);
1443                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1444                                 /* put the packet back and try again later */
1445                                 skb_queue_head(&pch->file.xq, skb);
1446                                 break;
1447                         }
1448                 }
1449         } else {
1450                 /* channel got deregistered */
1451                 skb_queue_purge(&pch->file.xq);
1452         }
1453         spin_unlock_bh(&pch->downl);
1454         /* see if there is anything from the attached unit to be sent */
1455         if (skb_queue_empty(&pch->file.xq)) {
1456                 read_lock_bh(&pch->upl);
1457                 ppp = pch->ppp;
1458                 if (ppp != 0)
1459                         ppp_xmit_process(ppp);
1460                 read_unlock_bh(&pch->upl);
1461         }
1462 }
1463
1464 /*
1465  * Receive-side routines.
1466  */
1467
1468 /* misuse a few fields of the skb for MP reconstruction */
1469 #define sequence        priority
1470 #define BEbits          cb[0]
1471
1472 static inline void
1473 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1474 {
1475         ppp_recv_lock(ppp);
1476         /* ppp->dev == 0 means interface is closing down */
1477         if (ppp->dev != 0)
1478                 ppp_receive_frame(ppp, skb, pch);
1479         else
1480                 kfree_skb(skb);
1481         ppp_recv_unlock(ppp);
1482 }
1483
1484 void
1485 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1486 {
1487         struct channel *pch = chan->ppp;
1488         int proto;
1489
1490         if (pch == 0 || skb->len == 0) {
1491                 kfree_skb(skb);
1492                 return;
1493         }
1494
1495         proto = PPP_PROTO(skb);
1496         read_lock_bh(&pch->upl);
1497         if (pch->ppp == 0 || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1498                 /* put it on the channel queue */
1499                 skb_queue_tail(&pch->file.rq, skb);
1500                 /* drop old frames if queue too long */
1501                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1502                        && (skb = skb_dequeue(&pch->file.rq)) != 0)
1503                         kfree_skb(skb);
1504                 wake_up_interruptible(&pch->file.rwait);
1505         } else {
1506                 ppp_do_recv(pch->ppp, skb, pch);
1507         }
1508         read_unlock_bh(&pch->upl);
1509 }
1510
1511 /* Put a 0-length skb in the receive queue as an error indication */
1512 void
1513 ppp_input_error(struct ppp_channel *chan, int code)
1514 {
1515         struct channel *pch = chan->ppp;
1516         struct sk_buff *skb;
1517
1518         if (pch == 0)
1519                 return;
1520
1521         read_lock_bh(&pch->upl);
1522         if (pch->ppp != 0) {
1523                 skb = alloc_skb(0, GFP_ATOMIC);
1524                 if (skb != 0) {
1525                         skb->len = 0;           /* probably unnecessary */
1526                         skb->cb[0] = code;
1527                         ppp_do_recv(pch->ppp, skb, pch);
1528                 }
1529         }
1530         read_unlock_bh(&pch->upl);
1531 }
1532
1533 /*
1534  * We come in here to process a received frame.
1535  * The receive side of the ppp unit is locked.
1536  */
1537 static void
1538 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1539 {
1540         if (skb->len >= 2) {
1541 #ifdef CONFIG_PPP_MULTILINK
1542                 /* XXX do channel-level decompression here */
1543                 if (PPP_PROTO(skb) == PPP_MP)
1544                         ppp_receive_mp_frame(ppp, skb, pch);
1545                 else
1546 #endif /* CONFIG_PPP_MULTILINK */
1547                         ppp_receive_nonmp_frame(ppp, skb);
1548                 return;
1549         }
1550
1551         if (skb->len > 0)
1552                 /* note: a 0-length skb is used as an error indication */
1553                 ++ppp->stats.rx_length_errors;
1554
1555         kfree_skb(skb);
1556         ppp_receive_error(ppp);
1557 }
1558
1559 static void
1560 ppp_receive_error(struct ppp *ppp)
1561 {
1562         ++ppp->stats.rx_errors;
1563         if (ppp->vj != 0)
1564                 slhc_toss(ppp->vj);
1565 }
1566
1567 static void
1568 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1569 {
1570         struct sk_buff *ns;
1571         int proto, len, npi;
1572
1573         /*
1574          * Decompress the frame, if compressed.
1575          * Note that some decompressors need to see uncompressed frames
1576          * that come in as well as compressed frames.
1577          */
1578         if (ppp->rc_state != 0 && (ppp->rstate & SC_DECOMP_RUN)
1579             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1580                 skb = ppp_decompress_frame(ppp, skb);
1581
1582         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1583                 goto err;
1584
1585         proto = PPP_PROTO(skb);
1586         switch (proto) {
1587         case PPP_VJC_COMP:
1588                 /* decompress VJ compressed packets */
1589                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1590                         goto err;
1591
1592                 if (skb_tailroom(skb) < 124) {
1593                         /* copy to a new sk_buff with more tailroom */
1594                         ns = dev_alloc_skb(skb->len + 128);
1595                         if (ns == 0) {
1596                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1597                                 goto err;
1598                         }
1599                         skb_reserve(ns, 2);
1600                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1601                         kfree_skb(skb);
1602                         skb = ns;
1603                 }
1604                 else
1605                         skb->ip_summed = CHECKSUM_NONE;
1606
1607                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1608                 if (len <= 0) {
1609                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1610                         goto err;
1611                 }
1612                 len += 2;
1613                 if (len > skb->len)
1614                         skb_put(skb, len - skb->len);
1615                 else if (len < skb->len)
1616                         skb_trim(skb, len);
1617                 proto = PPP_IP;
1618                 break;
1619
1620         case PPP_VJC_UNCOMP:
1621                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1622                         goto err;
1623                 
1624                 /* Until we fix the decompressor need to make sure
1625                  * data portion is linear.
1626                  */
1627                 if (!pskb_may_pull(skb, skb->len)) 
1628                         goto err;
1629
1630                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1631                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1632                         goto err;
1633                 }
1634                 proto = PPP_IP;
1635                 break;
1636
1637         case PPP_CCP:
1638                 ppp_ccp_peek(ppp, skb, 1);
1639                 break;
1640         }
1641
1642         ++ppp->stats.rx_packets;
1643         ppp->stats.rx_bytes += skb->len - 2;
1644
1645         npi = proto_to_npindex(proto);
1646         if (npi < 0) {
1647                 /* control or unknown frame - pass it to pppd */
1648                 skb_queue_tail(&ppp->file.rq, skb);
1649                 /* limit queue length by dropping old frames */
1650                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1651                        && (skb = skb_dequeue(&ppp->file.rq)) != 0)
1652                         kfree_skb(skb);
1653                 /* wake up any process polling or blocking on read */
1654                 wake_up_interruptible(&ppp->file.rwait);
1655
1656         } else {
1657                 /* network protocol frame - give it to the kernel */
1658
1659 #ifdef CONFIG_PPP_FILTER
1660                 /* check if the packet passes the pass and active filters */
1661                 /* the filter instructions are constructed assuming
1662                    a four-byte PPP header on each packet */
1663                 *skb_push(skb, 2) = 0;
1664                 if (ppp->pass_filter
1665                     && sk_run_filter(skb, ppp->pass_filter,
1666                                      ppp->pass_len) == 0) {
1667                         if (ppp->debug & 1)
1668                                 printk(KERN_DEBUG "PPP: inbound frame not passed\n");
1669                         kfree_skb(skb);
1670                         return;
1671                 }
1672                 if (!(ppp->active_filter
1673                       && sk_run_filter(skb, ppp->active_filter,
1674                                        ppp->active_len) == 0))
1675                         ppp->last_recv = jiffies;
1676                 skb_pull(skb, 2);
1677 #else
1678                 ppp->last_recv = jiffies;
1679 #endif /* CONFIG_PPP_FILTER */
1680
1681                 if ((ppp->dev->flags & IFF_UP) == 0
1682                     || ppp->npmode[npi] != NPMODE_PASS) {
1683                         kfree_skb(skb);
1684                 } else {
1685                         /* chop off protocol */
1686                         skb_pull_rcsum(skb, 2);
1687                         skb->dev = ppp->dev;
1688                         skb->protocol = htons(npindex_to_ethertype[npi]);
1689                         skb->mac.raw = skb->data;
1690                         netif_rx(skb);
1691                         ppp->dev->last_rx = jiffies;
1692                 }
1693         }
1694         return;
1695
1696  err:
1697         kfree_skb(skb);
1698         ppp_receive_error(ppp);
1699 }
1700
1701 static struct sk_buff *
1702 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1703 {
1704         int proto = PPP_PROTO(skb);
1705         struct sk_buff *ns;
1706         int len;
1707
1708         /* Until we fix all the decompressor's need to make sure
1709          * data portion is linear.
1710          */
1711         if (!pskb_may_pull(skb, skb->len))
1712                 goto err;
1713
1714         if (proto == PPP_COMP) {
1715                 ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
1716                 if (ns == 0) {
1717                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1718                         goto err;
1719                 }
1720                 /* the decompressor still expects the A/C bytes in the hdr */
1721                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1722                                 skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
1723                 if (len < 0) {
1724                         /* Pass the compressed frame to pppd as an
1725                            error indication. */
1726                         if (len == DECOMP_FATALERROR)
1727                                 ppp->rstate |= SC_DC_FERROR;
1728                         kfree_skb(ns);
1729                         goto err;
1730                 }
1731
1732                 kfree_skb(skb);
1733                 skb = ns;
1734                 skb_put(skb, len);
1735                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1736
1737         } else {
1738                 /* Uncompressed frame - pass to decompressor so it
1739                    can update its dictionary if necessary. */
1740                 if (ppp->rcomp->incomp)
1741                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1742                                            skb->len + 2);
1743         }
1744
1745         return skb;
1746
1747  err:
1748         ppp->rstate |= SC_DC_ERROR;
1749         ppp_receive_error(ppp);
1750         return skb;
1751 }
1752
1753 #ifdef CONFIG_PPP_MULTILINK
1754 /*
1755  * Receive a multilink frame.
1756  * We put it on the reconstruction queue and then pull off
1757  * as many completed frames as we can.
1758  */
1759 static void
1760 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1761 {
1762         u32 mask, seq;
1763         struct channel *ch;
1764         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1765
1766         if (!pskb_may_pull(skb, mphdrlen) || ppp->mrru == 0)
1767                 goto err;               /* no good, throw it away */
1768
1769         /* Decode sequence number and begin/end bits */
1770         if (ppp->flags & SC_MP_SHORTSEQ) {
1771                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1772                 mask = 0xfff;
1773         } else {
1774                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1775                 mask = 0xffffff;
1776         }
1777         skb->BEbits = skb->data[2];
1778         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1779
1780         /*
1781          * Do protocol ID decompression on the first fragment of each packet.
1782          */
1783         if ((skb->BEbits & B) && (skb->data[0] & 1))
1784                 *skb_push(skb, 1) = 0;
1785
1786         /*
1787          * Expand sequence number to 32 bits, making it as close
1788          * as possible to ppp->minseq.
1789          */
1790         seq |= ppp->minseq & ~mask;
1791         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1792                 seq += mask + 1;
1793         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1794                 seq -= mask + 1;        /* should never happen */
1795         skb->sequence = seq;
1796         pch->lastseq = seq;
1797
1798         /*
1799          * If this packet comes before the next one we were expecting,
1800          * drop it.
1801          */
1802         if (seq_before(seq, ppp->nextseq)) {
1803                 kfree_skb(skb);
1804                 ++ppp->stats.rx_dropped;
1805                 ppp_receive_error(ppp);
1806                 return;
1807         }
1808
1809         /*
1810          * Reevaluate minseq, the minimum over all channels of the
1811          * last sequence number received on each channel.  Because of
1812          * the increasing sequence number rule, we know that any fragment
1813          * before `minseq' which hasn't arrived is never going to arrive.
1814          * The list of channels can't change because we have the receive
1815          * side of the ppp unit locked.
1816          */
1817         list_for_each_entry(ch, &ppp->channels, clist) {
1818                 if (seq_before(ch->lastseq, seq))
1819                         seq = ch->lastseq;
1820         }
1821         if (seq_before(ppp->minseq, seq))
1822                 ppp->minseq = seq;
1823
1824         /* Put the fragment on the reconstruction queue */
1825         ppp_mp_insert(ppp, skb);
1826
1827         /* If the queue is getting long, don't wait any longer for packets
1828            before the start of the queue. */
1829         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN
1830             && seq_before(ppp->minseq, ppp->mrq.next->sequence))
1831                 ppp->minseq = ppp->mrq.next->sequence;
1832
1833         /* Pull completed packets off the queue and receive them. */
1834         while ((skb = ppp_mp_reconstruct(ppp)) != 0)
1835                 ppp_receive_nonmp_frame(ppp, skb);
1836
1837         return;
1838
1839  err:
1840         kfree_skb(skb);
1841         ppp_receive_error(ppp);
1842 }
1843
1844 /*
1845  * Insert a fragment on the MP reconstruction queue.
1846  * The queue is ordered by increasing sequence number.
1847  */
1848 static void
1849 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1850 {
1851         struct sk_buff *p;
1852         struct sk_buff_head *list = &ppp->mrq;
1853         u32 seq = skb->sequence;
1854
1855         /* N.B. we don't need to lock the list lock because we have the
1856            ppp unit receive-side lock. */
1857         for (p = list->next; p != (struct sk_buff *)list; p = p->next)
1858                 if (seq_before(seq, p->sequence))
1859                         break;
1860         __skb_insert(skb, p->prev, p, list);
1861 }
1862
1863 /*
1864  * Reconstruct a packet from the MP fragment queue.
1865  * We go through increasing sequence numbers until we find a
1866  * complete packet, or we get to the sequence number for a fragment
1867  * which hasn't arrived but might still do so.
1868  */
1869 struct sk_buff *
1870 ppp_mp_reconstruct(struct ppp *ppp)
1871 {
1872         u32 seq = ppp->nextseq;
1873         u32 minseq = ppp->minseq;
1874         struct sk_buff_head *list = &ppp->mrq;
1875         struct sk_buff *p, *next;
1876         struct sk_buff *head, *tail;
1877         struct sk_buff *skb = NULL;
1878         int lost = 0, len = 0;
1879
1880         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1881                 return NULL;
1882         head = list->next;
1883         tail = NULL;
1884         for (p = head; p != (struct sk_buff *) list; p = next) {
1885                 next = p->next;
1886                 if (seq_before(p->sequence, seq)) {
1887                         /* this can't happen, anyway ignore the skb */
1888                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1889                                p->sequence, seq);
1890                         head = next;
1891                         continue;
1892                 }
1893                 if (p->sequence != seq) {
1894                         /* Fragment `seq' is missing.  If it is after
1895                            minseq, it might arrive later, so stop here. */
1896                         if (seq_after(seq, minseq))
1897                                 break;
1898                         /* Fragment `seq' is lost, keep going. */
1899                         lost = 1;
1900                         seq = seq_before(minseq, p->sequence)?
1901                                 minseq + 1: p->sequence;
1902                         next = p;
1903                         continue;
1904                 }
1905
1906                 /*
1907                  * At this point we know that all the fragments from
1908                  * ppp->nextseq to seq are either present or lost.
1909                  * Also, there are no complete packets in the queue
1910                  * that have no missing fragments and end before this
1911                  * fragment.
1912                  */
1913
1914                 /* B bit set indicates this fragment starts a packet */
1915                 if (p->BEbits & B) {
1916                         head = p;
1917                         lost = 0;
1918                         len = 0;
1919                 }
1920
1921                 len += p->len;
1922
1923                 /* Got a complete packet yet? */
1924                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1925                         if (len > ppp->mrru + 2) {
1926                                 ++ppp->stats.rx_length_errors;
1927                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1928                                        " is too long (%d)\n", len);
1929                         } else if (p == head) {
1930                                 /* fragment is complete packet - reuse skb */
1931                                 tail = p;
1932                                 skb = skb_get(p);
1933                                 break;
1934                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1935                                 ++ppp->stats.rx_missed_errors;
1936                                 printk(KERN_DEBUG "PPP: no memory for "
1937                                        "reconstructed packet");
1938                         } else {
1939                                 tail = p;
1940                                 break;
1941                         }
1942                         ppp->nextseq = seq + 1;
1943                 }
1944
1945                 /*
1946                  * If this is the ending fragment of a packet,
1947                  * and we haven't found a complete valid packet yet,
1948                  * we can discard up to and including this fragment.
1949                  */
1950                 if (p->BEbits & E)
1951                         head = next;
1952
1953                 ++seq;
1954         }
1955
1956         /* If we have a complete packet, copy it all into one skb. */
1957         if (tail != NULL) {
1958                 /* If we have discarded any fragments,
1959                    signal a receive error. */
1960                 if (head->sequence != ppp->nextseq) {
1961                         if (ppp->debug & 1)
1962                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1963                                        ppp->nextseq, head->sequence-1);
1964                         ++ppp->stats.rx_dropped;
1965                         ppp_receive_error(ppp);
1966                 }
1967
1968                 if (head != tail)
1969                         /* copy to a single skb */
1970                         for (p = head; p != tail->next; p = p->next)
1971                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1972                 ppp->nextseq = tail->sequence + 1;
1973                 head = tail->next;
1974         }
1975
1976         /* Discard all the skbuffs that we have copied the data out of
1977            or that we can't use. */
1978         while ((p = list->next) != head) {
1979                 __skb_unlink(p, list);
1980                 kfree_skb(p);
1981         }
1982
1983         return skb;
1984 }
1985 #endif /* CONFIG_PPP_MULTILINK */
1986
1987 /*
1988  * Channel interface.
1989  */
1990
1991 /*
1992  * Create a new, unattached ppp channel.
1993  */
1994 int
1995 ppp_register_channel(struct ppp_channel *chan)
1996 {
1997         struct channel *pch;
1998
1999         pch = kmalloc(sizeof(struct channel), GFP_KERNEL);
2000         if (pch == 0)
2001                 return -ENOMEM;
2002         memset(pch, 0, sizeof(struct channel));
2003         pch->ppp = NULL;
2004         pch->chan = chan;
2005         chan->ppp = pch;
2006         init_ppp_file(&pch->file, CHANNEL);
2007         pch->file.hdrlen = chan->hdrlen;
2008 #ifdef CONFIG_PPP_MULTILINK
2009         pch->lastseq = -1;
2010 #endif /* CONFIG_PPP_MULTILINK */
2011         init_rwsem(&pch->chan_sem);
2012         spin_lock_init(&pch->downl);
2013         rwlock_init(&pch->upl);
2014         spin_lock_bh(&all_channels_lock);
2015         pch->file.index = ++last_channel_index;
2016         list_add(&pch->list, &new_channels);
2017         atomic_inc(&channel_count);
2018         spin_unlock_bh(&all_channels_lock);
2019         return 0;
2020 }
2021
2022 /*
2023  * Return the index of a channel.
2024  */
2025 int ppp_channel_index(struct ppp_channel *chan)
2026 {
2027         struct channel *pch = chan->ppp;
2028
2029         if (pch != 0)
2030                 return pch->file.index;
2031         return -1;
2032 }
2033
2034 /*
2035  * Return the PPP unit number to which a channel is connected.
2036  */
2037 int ppp_unit_number(struct ppp_channel *chan)
2038 {
2039         struct channel *pch = chan->ppp;
2040         int unit = -1;
2041
2042         if (pch != 0) {
2043                 read_lock_bh(&pch->upl);
2044                 if (pch->ppp != 0)
2045                         unit = pch->ppp->file.index;
2046                 read_unlock_bh(&pch->upl);
2047         }
2048         return unit;
2049 }
2050
2051 /*
2052  * Disconnect a channel from the generic layer.
2053  * This must be called in process context.
2054  */
2055 void
2056 ppp_unregister_channel(struct ppp_channel *chan)
2057 {
2058         struct channel *pch = chan->ppp;
2059
2060         if (pch == 0)
2061                 return;         /* should never happen */
2062         chan->ppp = NULL;
2063
2064         /*
2065          * This ensures that we have returned from any calls into the
2066          * the channel's start_xmit or ioctl routine before we proceed.
2067          */
2068         down_write(&pch->chan_sem);
2069         spin_lock_bh(&pch->downl);
2070         pch->chan = NULL;
2071         spin_unlock_bh(&pch->downl);
2072         up_write(&pch->chan_sem);
2073         ppp_disconnect_channel(pch);
2074         spin_lock_bh(&all_channels_lock);
2075         list_del(&pch->list);
2076         spin_unlock_bh(&all_channels_lock);
2077         pch->file.dead = 1;
2078         wake_up_interruptible(&pch->file.rwait);
2079         if (atomic_dec_and_test(&pch->file.refcnt))
2080                 ppp_destroy_channel(pch);
2081 }
2082
2083 /*
2084  * Callback from a channel when it can accept more to transmit.
2085  * This should be called at BH/softirq level, not interrupt level.
2086  */
2087 void
2088 ppp_output_wakeup(struct ppp_channel *chan)
2089 {
2090         struct channel *pch = chan->ppp;
2091
2092         if (pch == 0)
2093                 return;
2094         ppp_channel_push(pch);
2095 }
2096
2097 /*
2098  * Compression control.
2099  */
2100
2101 /* Process the PPPIOCSCOMPRESS ioctl. */
2102 static int
2103 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2104 {
2105         int err;
2106         struct compressor *cp, *ocomp;
2107         struct ppp_option_data data;
2108         void *state, *ostate;
2109         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2110
2111         err = -EFAULT;
2112         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2113             || (data.length <= CCP_MAX_OPTION_LENGTH
2114                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2115                 goto out;
2116         err = -EINVAL;
2117         if (data.length > CCP_MAX_OPTION_LENGTH
2118             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2119                 goto out;
2120
2121         cp = find_compressor(ccp_option[0]);
2122 #ifdef CONFIG_KMOD
2123         if (cp == 0) {
2124                 request_module("ppp-compress-%d", ccp_option[0]);
2125                 cp = find_compressor(ccp_option[0]);
2126         }
2127 #endif /* CONFIG_KMOD */
2128         if (cp == 0)
2129                 goto out;
2130
2131         err = -ENOBUFS;
2132         if (data.transmit) {
2133                 state = cp->comp_alloc(ccp_option, data.length);
2134                 if (state != 0) {
2135                         ppp_xmit_lock(ppp);
2136                         ppp->xstate &= ~SC_COMP_RUN;
2137                         ocomp = ppp->xcomp;
2138                         ostate = ppp->xc_state;
2139                         ppp->xcomp = cp;
2140                         ppp->xc_state = state;
2141                         ppp_xmit_unlock(ppp);
2142                         if (ostate != 0) {
2143                                 ocomp->comp_free(ostate);
2144                                 module_put(ocomp->owner);
2145                         }
2146                         err = 0;
2147                 } else
2148                         module_put(cp->owner);
2149
2150         } else {
2151                 state = cp->decomp_alloc(ccp_option, data.length);
2152                 if (state != 0) {
2153                         ppp_recv_lock(ppp);
2154                         ppp->rstate &= ~SC_DECOMP_RUN;
2155                         ocomp = ppp->rcomp;
2156                         ostate = ppp->rc_state;
2157                         ppp->rcomp = cp;
2158                         ppp->rc_state = state;
2159                         ppp_recv_unlock(ppp);
2160                         if (ostate != 0) {
2161                                 ocomp->decomp_free(ostate);
2162                                 module_put(ocomp->owner);
2163                         }
2164                         err = 0;
2165                 } else
2166                         module_put(cp->owner);
2167         }
2168
2169  out:
2170         return err;
2171 }
2172
2173 /*
2174  * Look at a CCP packet and update our state accordingly.
2175  * We assume the caller has the xmit or recv path locked.
2176  */
2177 static void
2178 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2179 {
2180         unsigned char *dp;
2181         int len;
2182
2183         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2184                 return; /* no header */
2185         dp = skb->data + 2;
2186
2187         switch (CCP_CODE(dp)) {
2188         case CCP_CONFREQ:
2189
2190                 /* A ConfReq starts negotiation of compression 
2191                  * in one direction of transmission,
2192                  * and hence brings it down...but which way?
2193                  *
2194                  * Remember:
2195                  * A ConfReq indicates what the sender would like to receive
2196                  */
2197                 if(inbound)
2198                         /* He is proposing what I should send */
2199                         ppp->xstate &= ~SC_COMP_RUN;
2200                 else    
2201                         /* I am proposing to what he should send */
2202                         ppp->rstate &= ~SC_DECOMP_RUN;
2203                 
2204                 break;
2205                 
2206         case CCP_TERMREQ:
2207         case CCP_TERMACK:
2208                 /*
2209                  * CCP is going down, both directions of transmission 
2210                  */
2211                 ppp->rstate &= ~SC_DECOMP_RUN;
2212                 ppp->xstate &= ~SC_COMP_RUN;
2213                 break;
2214
2215         case CCP_CONFACK:
2216                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2217                         break;
2218                 len = CCP_LENGTH(dp);
2219                 if (!pskb_may_pull(skb, len + 2))
2220                         return;         /* too short */
2221                 dp += CCP_HDRLEN;
2222                 len -= CCP_HDRLEN;
2223                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2224                         break;
2225                 if (inbound) {
2226                         /* we will start receiving compressed packets */
2227                         if (ppp->rc_state == 0)
2228                                 break;
2229                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2230                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2231                                 ppp->rstate |= SC_DECOMP_RUN;
2232                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2233                         }
2234                 } else {
2235                         /* we will soon start sending compressed packets */
2236                         if (ppp->xc_state == 0)
2237                                 break;
2238                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2239                                         ppp->file.index, 0, ppp->debug))
2240                                 ppp->xstate |= SC_COMP_RUN;
2241                 }
2242                 break;
2243
2244         case CCP_RESETACK:
2245                 /* reset the [de]compressor */
2246                 if ((ppp->flags & SC_CCP_UP) == 0)
2247                         break;
2248                 if (inbound) {
2249                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2250                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2251                                 ppp->rstate &= ~SC_DC_ERROR;
2252                         }
2253                 } else {
2254                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2255                                 ppp->xcomp->comp_reset(ppp->xc_state);
2256                 }
2257                 break;
2258         }
2259 }
2260
2261 /* Free up compression resources. */
2262 static void
2263 ppp_ccp_closed(struct ppp *ppp)
2264 {
2265         void *xstate, *rstate;
2266         struct compressor *xcomp, *rcomp;
2267
2268         ppp_lock(ppp);
2269         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2270         ppp->xstate = 0;
2271         xcomp = ppp->xcomp;
2272         xstate = ppp->xc_state;
2273         ppp->xc_state = NULL;
2274         ppp->rstate = 0;
2275         rcomp = ppp->rcomp;
2276         rstate = ppp->rc_state;
2277         ppp->rc_state = NULL;
2278         ppp_unlock(ppp);
2279
2280         if (xstate) {
2281                 xcomp->comp_free(xstate);
2282                 module_put(xcomp->owner);
2283         }
2284         if (rstate) {
2285                 rcomp->decomp_free(rstate);
2286                 module_put(rcomp->owner);
2287         }
2288 }
2289
2290 /* List of compressors. */
2291 static LIST_HEAD(compressor_list);
2292 static DEFINE_SPINLOCK(compressor_list_lock);
2293
2294 struct compressor_entry {
2295         struct list_head list;
2296         struct compressor *comp;
2297 };
2298
2299 static struct compressor_entry *
2300 find_comp_entry(int proto)
2301 {
2302         struct compressor_entry *ce;
2303
2304         list_for_each_entry(ce, &compressor_list, list) {
2305                 if (ce->comp->compress_proto == proto)
2306                         return ce;
2307         }
2308         return NULL;
2309 }
2310
2311 /* Register a compressor */
2312 int
2313 ppp_register_compressor(struct compressor *cp)
2314 {
2315         struct compressor_entry *ce;
2316         int ret;
2317         spin_lock(&compressor_list_lock);
2318         ret = -EEXIST;
2319         if (find_comp_entry(cp->compress_proto) != 0)
2320                 goto out;
2321         ret = -ENOMEM;
2322         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2323         if (ce == 0)
2324                 goto out;
2325         ret = 0;
2326         ce->comp = cp;
2327         list_add(&ce->list, &compressor_list);
2328  out:
2329         spin_unlock(&compressor_list_lock);
2330         return ret;
2331 }
2332
2333 /* Unregister a compressor */
2334 void
2335 ppp_unregister_compressor(struct compressor *cp)
2336 {
2337         struct compressor_entry *ce;
2338
2339         spin_lock(&compressor_list_lock);
2340         ce = find_comp_entry(cp->compress_proto);
2341         if (ce != 0 && ce->comp == cp) {
2342                 list_del(&ce->list);
2343                 kfree(ce);
2344         }
2345         spin_unlock(&compressor_list_lock);
2346 }
2347
2348 /* Find a compressor. */
2349 static struct compressor *
2350 find_compressor(int type)
2351 {
2352         struct compressor_entry *ce;
2353         struct compressor *cp = NULL;
2354
2355         spin_lock(&compressor_list_lock);
2356         ce = find_comp_entry(type);
2357         if (ce != 0) {
2358                 cp = ce->comp;
2359                 if (!try_module_get(cp->owner))
2360                         cp = NULL;
2361         }
2362         spin_unlock(&compressor_list_lock);
2363         return cp;
2364 }
2365
2366 /*
2367  * Miscelleneous stuff.
2368  */
2369
2370 static void
2371 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2372 {
2373         struct slcompress *vj = ppp->vj;
2374
2375         memset(st, 0, sizeof(*st));
2376         st->p.ppp_ipackets = ppp->stats.rx_packets;
2377         st->p.ppp_ierrors = ppp->stats.rx_errors;
2378         st->p.ppp_ibytes = ppp->stats.rx_bytes;
2379         st->p.ppp_opackets = ppp->stats.tx_packets;
2380         st->p.ppp_oerrors = ppp->stats.tx_errors;
2381         st->p.ppp_obytes = ppp->stats.tx_bytes;
2382         if (vj == 0)
2383                 return;
2384         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2385         st->vj.vjs_compressed = vj->sls_o_compressed;
2386         st->vj.vjs_searches = vj->sls_o_searches;
2387         st->vj.vjs_misses = vj->sls_o_misses;
2388         st->vj.vjs_errorin = vj->sls_i_error;
2389         st->vj.vjs_tossed = vj->sls_i_tossed;
2390         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2391         st->vj.vjs_compressedin = vj->sls_i_compressed;
2392 }
2393
2394 /*
2395  * Stuff for handling the lists of ppp units and channels
2396  * and for initialization.
2397  */
2398
2399 /*
2400  * Create a new ppp interface unit.  Fails if it can't allocate memory
2401  * or if there is already a unit with the requested number.
2402  * unit == -1 means allocate a new number.
2403  */
2404 static struct ppp *
2405 ppp_create_interface(int unit, int *retp)
2406 {
2407         struct ppp *ppp;
2408         struct net_device *dev = NULL;
2409         int ret = -ENOMEM;
2410         int i;
2411
2412         ppp = kmalloc(sizeof(struct ppp), GFP_KERNEL);
2413         if (!ppp)
2414                 goto out;
2415         dev = alloc_netdev(0, "", ppp_setup);
2416         if (!dev)
2417                 goto out1;
2418         memset(ppp, 0, sizeof(struct ppp));
2419
2420         ppp->mru = PPP_MRU;
2421         init_ppp_file(&ppp->file, INTERFACE);
2422         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2423         for (i = 0; i < NUM_NP; ++i)
2424                 ppp->npmode[i] = NPMODE_PASS;
2425         INIT_LIST_HEAD(&ppp->channels);
2426         spin_lock_init(&ppp->rlock);
2427         spin_lock_init(&ppp->wlock);
2428 #ifdef CONFIG_PPP_MULTILINK
2429         ppp->minseq = -1;
2430         skb_queue_head_init(&ppp->mrq);
2431 #endif /* CONFIG_PPP_MULTILINK */
2432         ppp->dev = dev;
2433         dev->priv = ppp;
2434
2435         dev->hard_start_xmit = ppp_start_xmit;
2436         dev->get_stats = ppp_net_stats;
2437         dev->do_ioctl = ppp_net_ioctl;
2438
2439         ret = -EEXIST;
2440         mutex_lock(&all_ppp_mutex);
2441         if (unit < 0)
2442                 unit = cardmap_find_first_free(all_ppp_units);
2443         else if (cardmap_get(all_ppp_units, unit) != NULL)
2444                 goto out2;      /* unit already exists */
2445
2446         /* Initialize the new ppp unit */
2447         ppp->file.index = unit;
2448         sprintf(dev->name, "ppp%d", unit);
2449
2450         ret = register_netdev(dev);
2451         if (ret != 0) {
2452                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2453                        dev->name, ret);
2454                 goto out2;
2455         }
2456
2457         atomic_inc(&ppp_unit_count);
2458         cardmap_set(&all_ppp_units, unit, ppp);
2459         mutex_unlock(&all_ppp_mutex);
2460         *retp = 0;
2461         return ppp;
2462
2463 out2:
2464         mutex_unlock(&all_ppp_mutex);
2465         free_netdev(dev);
2466 out1:
2467         kfree(ppp);
2468 out:
2469         *retp = ret;
2470         return NULL;
2471 }
2472
2473 /*
2474  * Initialize a ppp_file structure.
2475  */
2476 static void
2477 init_ppp_file(struct ppp_file *pf, int kind)
2478 {
2479         pf->kind = kind;
2480         skb_queue_head_init(&pf->xq);
2481         skb_queue_head_init(&pf->rq);
2482         atomic_set(&pf->refcnt, 1);
2483         init_waitqueue_head(&pf->rwait);
2484 }
2485
2486 /*
2487  * Take down a ppp interface unit - called when the owning file
2488  * (the one that created the unit) is closed or detached.
2489  */
2490 static void ppp_shutdown_interface(struct ppp *ppp)
2491 {
2492         struct net_device *dev;
2493
2494         mutex_lock(&all_ppp_mutex);
2495         ppp_lock(ppp);
2496         dev = ppp->dev;
2497         ppp->dev = NULL;
2498         ppp_unlock(ppp);
2499         /* This will call dev_close() for us. */
2500         if (dev) {
2501                 unregister_netdev(dev);
2502                 free_netdev(dev);
2503         }
2504         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2505         ppp->file.dead = 1;
2506         ppp->owner = NULL;
2507         wake_up_interruptible(&ppp->file.rwait);
2508         mutex_unlock(&all_ppp_mutex);
2509 }
2510
2511 /*
2512  * Free the memory used by a ppp unit.  This is only called once
2513  * there are no channels connected to the unit and no file structs
2514  * that reference the unit.
2515  */
2516 static void ppp_destroy_interface(struct ppp *ppp)
2517 {
2518         atomic_dec(&ppp_unit_count);
2519
2520         if (!ppp->file.dead || ppp->n_channels) {
2521                 /* "can't happen" */
2522                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2523                        "n_channels=%d !\n", ppp, ppp->file.dead,
2524                        ppp->n_channels);
2525                 return;
2526         }
2527
2528         ppp_ccp_closed(ppp);
2529         if (ppp->vj) {
2530                 slhc_free(ppp->vj);
2531                 ppp->vj = NULL;
2532         }
2533         skb_queue_purge(&ppp->file.xq);
2534         skb_queue_purge(&ppp->file.rq);
2535 #ifdef CONFIG_PPP_MULTILINK
2536         skb_queue_purge(&ppp->mrq);
2537 #endif /* CONFIG_PPP_MULTILINK */
2538 #ifdef CONFIG_PPP_FILTER
2539         kfree(ppp->pass_filter);
2540         ppp->pass_filter = NULL;
2541         kfree(ppp->active_filter);
2542         ppp->active_filter = NULL;
2543 #endif /* CONFIG_PPP_FILTER */
2544
2545         kfree(ppp);
2546 }
2547
2548 /*
2549  * Locate an existing ppp unit.
2550  * The caller should have locked the all_ppp_mutex.
2551  */
2552 static struct ppp *
2553 ppp_find_unit(int unit)
2554 {
2555         return cardmap_get(all_ppp_units, unit);
2556 }
2557
2558 /*
2559  * Locate an existing ppp channel.
2560  * The caller should have locked the all_channels_lock.
2561  * First we look in the new_channels list, then in the
2562  * all_channels list.  If found in the new_channels list,
2563  * we move it to the all_channels list.  This is for speed
2564  * when we have a lot of channels in use.
2565  */
2566 static struct channel *
2567 ppp_find_channel(int unit)
2568 {
2569         struct channel *pch;
2570
2571         list_for_each_entry(pch, &new_channels, list) {
2572                 if (pch->file.index == unit) {
2573                         list_move(&pch->list, &all_channels);
2574                         return pch;
2575                 }
2576         }
2577         list_for_each_entry(pch, &all_channels, list) {
2578                 if (pch->file.index == unit)
2579                         return pch;
2580         }
2581         return NULL;
2582 }
2583
2584 /*
2585  * Connect a PPP channel to a PPP interface unit.
2586  */
2587 static int
2588 ppp_connect_channel(struct channel *pch, int unit)
2589 {
2590         struct ppp *ppp;
2591         int ret = -ENXIO;
2592         int hdrlen;
2593
2594         mutex_lock(&all_ppp_mutex);
2595         ppp = ppp_find_unit(unit);
2596         if (ppp == 0)
2597                 goto out;
2598         write_lock_bh(&pch->upl);
2599         ret = -EINVAL;
2600         if (pch->ppp != 0)
2601                 goto outl;
2602
2603         ppp_lock(ppp);
2604         if (pch->file.hdrlen > ppp->file.hdrlen)
2605                 ppp->file.hdrlen = pch->file.hdrlen;
2606         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2607         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2608                 ppp->dev->hard_header_len = hdrlen;
2609         list_add_tail(&pch->clist, &ppp->channels);
2610         ++ppp->n_channels;
2611         pch->ppp = ppp;
2612         atomic_inc(&ppp->file.refcnt);
2613         ppp_unlock(ppp);
2614         ret = 0;
2615
2616  outl:
2617         write_unlock_bh(&pch->upl);
2618  out:
2619         mutex_unlock(&all_ppp_mutex);
2620         return ret;
2621 }
2622
2623 /*
2624  * Disconnect a channel from its ppp unit.
2625  */
2626 static int
2627 ppp_disconnect_channel(struct channel *pch)
2628 {
2629         struct ppp *ppp;
2630         int err = -EINVAL;
2631
2632         write_lock_bh(&pch->upl);
2633         ppp = pch->ppp;
2634         pch->ppp = NULL;
2635         write_unlock_bh(&pch->upl);
2636         if (ppp != 0) {
2637                 /* remove it from the ppp unit's list */
2638                 ppp_lock(ppp);
2639                 list_del(&pch->clist);
2640                 if (--ppp->n_channels == 0)
2641                         wake_up_interruptible(&ppp->file.rwait);
2642                 ppp_unlock(ppp);
2643                 if (atomic_dec_and_test(&ppp->file.refcnt))
2644                         ppp_destroy_interface(ppp);
2645                 err = 0;
2646         }
2647         return err;
2648 }
2649
2650 /*
2651  * Free up the resources used by a ppp channel.
2652  */
2653 static void ppp_destroy_channel(struct channel *pch)
2654 {
2655         atomic_dec(&channel_count);
2656
2657         if (!pch->file.dead) {
2658                 /* "can't happen" */
2659                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2660                        pch);
2661                 return;
2662         }
2663         skb_queue_purge(&pch->file.xq);
2664         skb_queue_purge(&pch->file.rq);
2665         kfree(pch);
2666 }
2667
2668 static void __exit ppp_cleanup(void)
2669 {
2670         /* should never happen */
2671         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2672                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2673         cardmap_destroy(&all_ppp_units);
2674         if (unregister_chrdev(PPP_MAJOR, "ppp") != 0)
2675                 printk(KERN_ERR "PPP: failed to unregister PPP device\n");
2676         class_device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2677         class_destroy(ppp_class);
2678 }
2679
2680 /*
2681  * Cardmap implementation.
2682  */
2683 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2684 {
2685         struct cardmap *p;
2686         int i;
2687
2688         for (p = map; p != NULL; ) {
2689                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2690                         return NULL;
2691                 if (p->shift == 0)
2692                         return p->ptr[i];
2693                 nr &= ~(CARDMAP_MASK << p->shift);
2694                 p = p->ptr[i];
2695         }
2696         return NULL;
2697 }
2698
2699 static void cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2700 {
2701         struct cardmap *p;
2702         int i;
2703
2704         p = *pmap;
2705         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2706                 do {
2707                         /* need a new top level */
2708                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2709                         memset(np, 0, sizeof(*np));
2710                         np->ptr[0] = p;
2711                         if (p != NULL) {
2712                                 np->shift = p->shift + CARDMAP_ORDER;
2713                                 p->parent = np;
2714                         } else
2715                                 np->shift = 0;
2716                         p = np;
2717                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2718                 *pmap = p;
2719         }
2720         while (p->shift > 0) {
2721                 i = (nr >> p->shift) & CARDMAP_MASK;
2722                 if (p->ptr[i] == NULL) {
2723                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2724                         memset(np, 0, sizeof(*np));
2725                         np->shift = p->shift - CARDMAP_ORDER;
2726                         np->parent = p;
2727                         p->ptr[i] = np;
2728                 }
2729                 if (ptr == NULL)
2730                         clear_bit(i, &p->inuse);
2731                 p = p->ptr[i];
2732         }
2733         i = nr & CARDMAP_MASK;
2734         p->ptr[i] = ptr;
2735         if (ptr != NULL)
2736                 set_bit(i, &p->inuse);
2737         else
2738                 clear_bit(i, &p->inuse);
2739 }
2740
2741 static unsigned int cardmap_find_first_free(struct cardmap *map)
2742 {
2743         struct cardmap *p;
2744         unsigned int nr = 0;
2745         int i;
2746
2747         if ((p = map) == NULL)
2748                 return 0;
2749         for (;;) {
2750                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2751                 if (i >= CARDMAP_WIDTH) {
2752                         if (p->parent == NULL)
2753                                 return CARDMAP_WIDTH << p->shift;
2754                         p = p->parent;
2755                         i = (nr >> p->shift) & CARDMAP_MASK;
2756                         set_bit(i, &p->inuse);
2757                         continue;
2758                 }
2759                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2760                 if (p->shift == 0 || p->ptr[i] == NULL)
2761                         return nr;
2762                 p = p->ptr[i];
2763         }
2764 }
2765
2766 static void cardmap_destroy(struct cardmap **pmap)
2767 {
2768         struct cardmap *p, *np;
2769         int i;
2770
2771         for (p = *pmap; p != NULL; p = np) {
2772                 if (p->shift != 0) {
2773                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2774                                 if (p->ptr[i] != NULL)
2775                                         break;
2776                         if (i < CARDMAP_WIDTH) {
2777                                 np = p->ptr[i];
2778                                 p->ptr[i] = NULL;
2779                                 continue;
2780                         }
2781                 }
2782                 np = p->parent;
2783                 kfree(p);
2784         }
2785         *pmap = NULL;
2786 }
2787
2788 /* Module/initialization stuff */
2789
2790 module_init(ppp_init);
2791 module_exit(ppp_cleanup);
2792
2793 EXPORT_SYMBOL(ppp_register_channel);
2794 EXPORT_SYMBOL(ppp_unregister_channel);
2795 EXPORT_SYMBOL(ppp_channel_index);
2796 EXPORT_SYMBOL(ppp_unit_number);
2797 EXPORT_SYMBOL(ppp_input);
2798 EXPORT_SYMBOL(ppp_input_error);
2799 EXPORT_SYMBOL(ppp_output_wakeup);
2800 EXPORT_SYMBOL(ppp_register_compressor);
2801 EXPORT_SYMBOL(ppp_unregister_compressor);
2802 MODULE_LICENSE("GPL");
2803 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2804 MODULE_ALIAS("/dev/ppp");