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