[PATCH] sem2mutex: drivers: raw, connector, dcdbas, ppp_generic
[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                 err = devfs_mk_cdev(MKDEV(PPP_MAJOR, 0),
867                                 S_IFCHR|S_IRUSR|S_IWUSR, "ppp");
868                 if (err)
869                         goto out_class;
870         }
871
872 out:
873         if (err)
874                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
875         return err;
876
877 out_class:
878         class_device_destroy(ppp_class, MKDEV(PPP_MAJOR,0));
879         class_destroy(ppp_class);
880 out_chrdev:
881         unregister_chrdev(PPP_MAJOR, "ppp");
882         goto out;
883 }
884
885 /*
886  * Network interface unit routines.
887  */
888 static int
889 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
890 {
891         struct ppp *ppp = (struct ppp *) dev->priv;
892         int npi, proto;
893         unsigned char *pp;
894
895         npi = ethertype_to_npindex(ntohs(skb->protocol));
896         if (npi < 0)
897                 goto outf;
898
899         /* Drop, accept or reject the packet */
900         switch (ppp->npmode[npi]) {
901         case NPMODE_PASS:
902                 break;
903         case NPMODE_QUEUE:
904                 /* it would be nice to have a way to tell the network
905                    system to queue this one up for later. */
906                 goto outf;
907         case NPMODE_DROP:
908         case NPMODE_ERROR:
909                 goto outf;
910         }
911
912         /* Put the 2-byte PPP protocol number on the front,
913            making sure there is room for the address and control fields. */
914         if (skb_headroom(skb) < PPP_HDRLEN) {
915                 struct sk_buff *ns;
916
917                 ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);
918                 if (ns == 0)
919                         goto outf;
920                 skb_reserve(ns, dev->hard_header_len);
921                 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
922                 kfree_skb(skb);
923                 skb = ns;
924         }
925         pp = skb_push(skb, 2);
926         proto = npindex_to_proto[npi];
927         pp[0] = proto >> 8;
928         pp[1] = proto;
929
930         netif_stop_queue(dev);
931         skb_queue_tail(&ppp->file.xq, skb);
932         ppp_xmit_process(ppp);
933         return 0;
934
935  outf:
936         kfree_skb(skb);
937         ++ppp->stats.tx_dropped;
938         return 0;
939 }
940
941 static struct net_device_stats *
942 ppp_net_stats(struct net_device *dev)
943 {
944         struct ppp *ppp = (struct ppp *) dev->priv;
945
946         return &ppp->stats;
947 }
948
949 static int
950 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
951 {
952         struct ppp *ppp = dev->priv;
953         int err = -EFAULT;
954         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
955         struct ppp_stats stats;
956         struct ppp_comp_stats cstats;
957         char *vers;
958
959         switch (cmd) {
960         case SIOCGPPPSTATS:
961                 ppp_get_stats(ppp, &stats);
962                 if (copy_to_user(addr, &stats, sizeof(stats)))
963                         break;
964                 err = 0;
965                 break;
966
967         case SIOCGPPPCSTATS:
968                 memset(&cstats, 0, sizeof(cstats));
969                 if (ppp->xc_state != 0)
970                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
971                 if (ppp->rc_state != 0)
972                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
973                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
974                         break;
975                 err = 0;
976                 break;
977
978         case SIOCGPPPVER:
979                 vers = PPP_VERSION;
980                 if (copy_to_user(addr, vers, strlen(vers) + 1))
981                         break;
982                 err = 0;
983                 break;
984
985         default:
986                 err = -EINVAL;
987         }
988
989         return err;
990 }
991
992 static void ppp_setup(struct net_device *dev)
993 {
994         dev->hard_header_len = PPP_HDRLEN;
995         dev->mtu = PPP_MTU;
996         dev->addr_len = 0;
997         dev->tx_queue_len = 3;
998         dev->type = ARPHRD_PPP;
999         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1000 }
1001
1002 /*
1003  * Transmit-side routines.
1004  */
1005
1006 /*
1007  * Called to do any work queued up on the transmit side
1008  * that can now be done.
1009  */
1010 static void
1011 ppp_xmit_process(struct ppp *ppp)
1012 {
1013         struct sk_buff *skb;
1014
1015         ppp_xmit_lock(ppp);
1016         if (ppp->dev != 0) {
1017                 ppp_push(ppp);
1018                 while (ppp->xmit_pending == 0
1019                        && (skb = skb_dequeue(&ppp->file.xq)) != 0)
1020                         ppp_send_frame(ppp, skb);
1021                 /* If there's no work left to do, tell the core net
1022                    code that we can accept some more. */
1023                 if (ppp->xmit_pending == 0 && skb_peek(&ppp->file.xq) == 0)
1024                         netif_wake_queue(ppp->dev);
1025         }
1026         ppp_xmit_unlock(ppp);
1027 }
1028
1029 static inline struct sk_buff *
1030 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1031 {
1032         struct sk_buff *new_skb;
1033         int len;
1034         int new_skb_size = ppp->dev->mtu +
1035                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1036         int compressor_skb_size = ppp->dev->mtu +
1037                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1038         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1039         if (!new_skb) {
1040                 if (net_ratelimit())
1041                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1042                 return NULL;
1043         }
1044         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1045                 skb_reserve(new_skb,
1046                             ppp->dev->hard_header_len - PPP_HDRLEN);
1047
1048         /* compressor still expects A/C bytes in hdr */
1049         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1050                                    new_skb->data, skb->len + 2,
1051                                    compressor_skb_size);
1052         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1053                 kfree_skb(skb);
1054                 skb = new_skb;
1055                 skb_put(skb, len);
1056                 skb_pull(skb, 2);       /* pull off A/C bytes */
1057         } else if (len == 0) {
1058                 /* didn't compress, or CCP not up yet */
1059                 kfree_skb(new_skb);
1060                 new_skb = skb;
1061         } else {
1062                 /*
1063                  * (len < 0)
1064                  * MPPE requires that we do not send unencrypted
1065                  * frames.  The compressor will return -1 if we
1066                  * should drop the frame.  We cannot simply test
1067                  * the compress_proto because MPPE and MPPC share
1068                  * the same number.
1069                  */
1070                 if (net_ratelimit())
1071                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1072                 kfree_skb(skb);
1073                 kfree_skb(new_skb);
1074                 new_skb = NULL;
1075         }
1076         return new_skb;
1077 }
1078
1079 /*
1080  * Compress and send a frame.
1081  * The caller should have locked the xmit path,
1082  * and xmit_pending should be 0.
1083  */
1084 static void
1085 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1086 {
1087         int proto = PPP_PROTO(skb);
1088         struct sk_buff *new_skb;
1089         int len;
1090         unsigned char *cp;
1091
1092         if (proto < 0x8000) {
1093 #ifdef CONFIG_PPP_FILTER
1094                 /* check if we should pass this packet */
1095                 /* the filter instructions are constructed assuming
1096                    a four-byte PPP header on each packet */
1097                 *skb_push(skb, 2) = 1;
1098                 if (ppp->pass_filter
1099                     && sk_run_filter(skb, ppp->pass_filter,
1100                                      ppp->pass_len) == 0) {
1101                         if (ppp->debug & 1)
1102                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1103                         kfree_skb(skb);
1104                         return;
1105                 }
1106                 /* if this packet passes the active filter, record the time */
1107                 if (!(ppp->active_filter
1108                       && sk_run_filter(skb, ppp->active_filter,
1109                                        ppp->active_len) == 0))
1110                         ppp->last_xmit = jiffies;
1111                 skb_pull(skb, 2);
1112 #else
1113                 /* for data packets, record the time */
1114                 ppp->last_xmit = jiffies;
1115 #endif /* CONFIG_PPP_FILTER */
1116         }
1117
1118         ++ppp->stats.tx_packets;
1119         ppp->stats.tx_bytes += skb->len - 2;
1120
1121         switch (proto) {
1122         case PPP_IP:
1123                 if (ppp->vj == 0 || (ppp->flags & SC_COMP_TCP) == 0)
1124                         break;
1125                 /* try to do VJ TCP header compression */
1126                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1127                                     GFP_ATOMIC);
1128                 if (new_skb == 0) {
1129                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1130                         goto drop;
1131                 }
1132                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1133                 cp = skb->data + 2;
1134                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1135                                     new_skb->data + 2, &cp,
1136                                     !(ppp->flags & SC_NO_TCP_CCID));
1137                 if (cp == skb->data + 2) {
1138                         /* didn't compress */
1139                         kfree_skb(new_skb);
1140                 } else {
1141                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1142                                 proto = PPP_VJC_COMP;
1143                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1144                         } else {
1145                                 proto = PPP_VJC_UNCOMP;
1146                                 cp[0] = skb->data[2];
1147                         }
1148                         kfree_skb(skb);
1149                         skb = new_skb;
1150                         cp = skb_put(skb, len + 2);
1151                         cp[0] = 0;
1152                         cp[1] = proto;
1153                 }
1154                 break;
1155
1156         case PPP_CCP:
1157                 /* peek at outbound CCP frames */
1158                 ppp_ccp_peek(ppp, skb, 0);
1159                 break;
1160         }
1161
1162         /* try to do packet compression */
1163         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
1164             && proto != PPP_LCP && proto != PPP_CCP) {
1165                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1166                         if (net_ratelimit())
1167                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1168                         goto drop;
1169                 }
1170                 skb = pad_compress_skb(ppp, skb);
1171                 if (!skb)
1172                         goto drop;
1173         }
1174
1175         /*
1176          * If we are waiting for traffic (demand dialling),
1177          * queue it up for pppd to receive.
1178          */
1179         if (ppp->flags & SC_LOOP_TRAFFIC) {
1180                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1181                         goto drop;
1182                 skb_queue_tail(&ppp->file.rq, skb);
1183                 wake_up_interruptible(&ppp->file.rwait);
1184                 return;
1185         }
1186
1187         ppp->xmit_pending = skb;
1188         ppp_push(ppp);
1189         return;
1190
1191  drop:
1192         if (skb)
1193                 kfree_skb(skb);
1194         ++ppp->stats.tx_errors;
1195 }
1196
1197 /*
1198  * Try to send the frame in xmit_pending.
1199  * The caller should have the xmit path locked.
1200  */
1201 static void
1202 ppp_push(struct ppp *ppp)
1203 {
1204         struct list_head *list;
1205         struct channel *pch;
1206         struct sk_buff *skb = ppp->xmit_pending;
1207
1208         if (skb == 0)
1209                 return;
1210
1211         list = &ppp->channels;
1212         if (list_empty(list)) {
1213                 /* nowhere to send the packet, just drop it */
1214                 ppp->xmit_pending = NULL;
1215                 kfree_skb(skb);
1216                 return;
1217         }
1218
1219         if ((ppp->flags & SC_MULTILINK) == 0) {
1220                 /* not doing multilink: send it down the first channel */
1221                 list = list->next;
1222                 pch = list_entry(list, struct channel, clist);
1223
1224                 spin_lock_bh(&pch->downl);
1225                 if (pch->chan) {
1226                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1227                                 ppp->xmit_pending = NULL;
1228                 } else {
1229                         /* channel got unregistered */
1230                         kfree_skb(skb);
1231                         ppp->xmit_pending = NULL;
1232                 }
1233                 spin_unlock_bh(&pch->downl);
1234                 return;
1235         }
1236
1237 #ifdef CONFIG_PPP_MULTILINK
1238         /* Multilink: fragment the packet over as many links
1239            as can take the packet at the moment. */
1240         if (!ppp_mp_explode(ppp, skb))
1241                 return;
1242 #endif /* CONFIG_PPP_MULTILINK */
1243
1244         ppp->xmit_pending = NULL;
1245         kfree_skb(skb);
1246 }
1247
1248 #ifdef CONFIG_PPP_MULTILINK
1249 /*
1250  * Divide a packet to be transmitted into fragments and
1251  * send them out the individual links.
1252  */
1253 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1254 {
1255         int len, fragsize;
1256         int i, bits, hdrlen, mtu;
1257         int flen;
1258         int navail, nfree;
1259         int nbigger;
1260         unsigned char *p, *q;
1261         struct list_head *list;
1262         struct channel *pch;
1263         struct sk_buff *frag;
1264         struct ppp_channel *chan;
1265
1266         nfree = 0;      /* # channels which have no packet already queued */
1267         navail = 0;     /* total # of usable channels (not deregistered) */
1268         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1269         i = 0;
1270         list_for_each_entry(pch, &ppp->channels, clist) {
1271                 navail += pch->avail = (pch->chan != NULL);
1272                 if (pch->avail) {
1273                         if (skb_queue_empty(&pch->file.xq) ||
1274                             !pch->had_frag) {
1275                                 pch->avail = 2;
1276                                 ++nfree;
1277                         }
1278                         if (!pch->had_frag && i < ppp->nxchan)
1279                                 ppp->nxchan = i;
1280                 }
1281                 ++i;
1282         }
1283
1284         /*
1285          * Don't start sending this packet unless at least half of
1286          * the channels are free.  This gives much better TCP
1287          * performance if we have a lot of channels.
1288          */
1289         if (nfree == 0 || nfree < navail / 2)
1290                 return 0;       /* can't take now, leave it in xmit_pending */
1291
1292         /* Do protocol field compression (XXX this should be optional) */
1293         p = skb->data;
1294         len = skb->len;
1295         if (*p == 0) {
1296                 ++p;
1297                 --len;
1298         }
1299
1300         /*
1301          * Decide on fragment size.
1302          * We create a fragment for each free channel regardless of
1303          * how small they are (i.e. even 0 length) in order to minimize
1304          * the time that it will take to detect when a channel drops
1305          * a fragment.
1306          */
1307         fragsize = len;
1308         if (nfree > 1)
1309                 fragsize = ROUNDUP(fragsize, nfree);
1310         /* nbigger channels get fragsize bytes, the rest get fragsize-1,
1311            except if nbigger==0, then they all get fragsize. */
1312         nbigger = len % nfree;
1313
1314         /* skip to the channel after the one we last used
1315            and start at that one */
1316         list = &ppp->channels;
1317         for (i = 0; i < ppp->nxchan; ++i) {
1318                 list = list->next;
1319                 if (list == &ppp->channels) {
1320                         i = 0;
1321                         break;
1322                 }
1323         }
1324
1325         /* create a fragment for each channel */
1326         bits = B;
1327         while (nfree > 0 || len > 0) {
1328                 list = list->next;
1329                 if (list == &ppp->channels) {
1330                         i = 0;
1331                         continue;
1332                 }
1333                 pch = list_entry(list, struct channel, clist);
1334                 ++i;
1335                 if (!pch->avail)
1336                         continue;
1337
1338                 /*
1339                  * Skip this channel if it has a fragment pending already and
1340                  * we haven't given a fragment to all of the free channels.
1341                  */
1342                 if (pch->avail == 1) {
1343                         if (nfree > 0)
1344                                 continue;
1345                 } else {
1346                         --nfree;
1347                         pch->avail = 1;
1348                 }
1349
1350                 /* check the channel's mtu and whether it is still attached. */
1351                 spin_lock_bh(&pch->downl);
1352                 if (pch->chan == NULL) {
1353                         /* can't use this channel, it's being deregistered */
1354                         spin_unlock_bh(&pch->downl);
1355                         pch->avail = 0;
1356                         if (--navail == 0)
1357                                 break;
1358                         continue;
1359                 }
1360
1361                 /*
1362                  * Create a fragment for this channel of
1363                  * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
1364                  * If mtu+2-hdrlen < 4, that is a ridiculously small
1365                  * MTU, so we use mtu = 2 + hdrlen.
1366                  */
1367                 if (fragsize > len)
1368                         fragsize = len;
1369                 flen = fragsize;
1370                 mtu = pch->chan->mtu + 2 - hdrlen;
1371                 if (mtu < 4)
1372                         mtu = 4;
1373                 if (flen > mtu)
1374                         flen = mtu;
1375                 if (flen == len && nfree == 0)
1376                         bits |= E;
1377                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1378                 if (frag == 0)
1379                         goto noskb;
1380                 q = skb_put(frag, flen + hdrlen);
1381
1382                 /* make the MP header */
1383                 q[0] = PPP_MP >> 8;
1384                 q[1] = PPP_MP;
1385                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1386                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1387                         q[3] = ppp->nxseq;
1388                 } else {
1389                         q[2] = bits;
1390                         q[3] = ppp->nxseq >> 16;
1391                         q[4] = ppp->nxseq >> 8;
1392                         q[5] = ppp->nxseq;
1393                 }
1394
1395                 /*
1396                  * Copy the data in.
1397                  * Unfortunately there is a bug in older versions of
1398                  * the Linux PPP multilink reconstruction code where it
1399                  * drops 0-length fragments.  Therefore we make sure the
1400                  * fragment has at least one byte of data.  Any bytes
1401                  * we add in this situation will end up as padding on the
1402                  * end of the reconstructed packet.
1403                  */
1404                 if (flen == 0)
1405                         *skb_put(frag, 1) = 0;
1406                 else
1407                         memcpy(q + hdrlen, p, flen);
1408
1409                 /* try to send it down the channel */
1410                 chan = pch->chan;
1411                 if (!skb_queue_empty(&pch->file.xq) ||
1412                     !chan->ops->start_xmit(chan, frag))
1413                         skb_queue_tail(&pch->file.xq, frag);
1414                 pch->had_frag = 1;
1415                 p += flen;
1416                 len -= flen;
1417                 ++ppp->nxseq;
1418                 bits = 0;
1419                 spin_unlock_bh(&pch->downl);
1420
1421                 if (--nbigger == 0 && fragsize > 0)
1422                         --fragsize;
1423         }
1424         ppp->nxchan = i;
1425
1426         return 1;
1427
1428  noskb:
1429         spin_unlock_bh(&pch->downl);
1430         if (ppp->debug & 1)
1431                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1432         ++ppp->stats.tx_errors;
1433         ++ppp->nxseq;
1434         return 1;       /* abandon the frame */
1435 }
1436 #endif /* CONFIG_PPP_MULTILINK */
1437
1438 /*
1439  * Try to send data out on a channel.
1440  */
1441 static void
1442 ppp_channel_push(struct channel *pch)
1443 {
1444         struct sk_buff *skb;
1445         struct ppp *ppp;
1446
1447         spin_lock_bh(&pch->downl);
1448         if (pch->chan != 0) {
1449                 while (!skb_queue_empty(&pch->file.xq)) {
1450                         skb = skb_dequeue(&pch->file.xq);
1451                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1452                                 /* put the packet back and try again later */
1453                                 skb_queue_head(&pch->file.xq, skb);
1454                                 break;
1455                         }
1456                 }
1457         } else {
1458                 /* channel got deregistered */
1459                 skb_queue_purge(&pch->file.xq);
1460         }
1461         spin_unlock_bh(&pch->downl);
1462         /* see if there is anything from the attached unit to be sent */
1463         if (skb_queue_empty(&pch->file.xq)) {
1464                 read_lock_bh(&pch->upl);
1465                 ppp = pch->ppp;
1466                 if (ppp != 0)
1467                         ppp_xmit_process(ppp);
1468                 read_unlock_bh(&pch->upl);
1469         }
1470 }
1471
1472 /*
1473  * Receive-side routines.
1474  */
1475
1476 /* misuse a few fields of the skb for MP reconstruction */
1477 #define sequence        priority
1478 #define BEbits          cb[0]
1479
1480 static inline void
1481 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1482 {
1483         ppp_recv_lock(ppp);
1484         /* ppp->dev == 0 means interface is closing down */
1485         if (ppp->dev != 0)
1486                 ppp_receive_frame(ppp, skb, pch);
1487         else
1488                 kfree_skb(skb);
1489         ppp_recv_unlock(ppp);
1490 }
1491
1492 void
1493 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1494 {
1495         struct channel *pch = chan->ppp;
1496         int proto;
1497
1498         if (pch == 0 || skb->len == 0) {
1499                 kfree_skb(skb);
1500                 return;
1501         }
1502
1503         proto = PPP_PROTO(skb);
1504         read_lock_bh(&pch->upl);
1505         if (pch->ppp == 0 || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1506                 /* put it on the channel queue */
1507                 skb_queue_tail(&pch->file.rq, skb);
1508                 /* drop old frames if queue too long */
1509                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1510                        && (skb = skb_dequeue(&pch->file.rq)) != 0)
1511                         kfree_skb(skb);
1512                 wake_up_interruptible(&pch->file.rwait);
1513         } else {
1514                 ppp_do_recv(pch->ppp, skb, pch);
1515         }
1516         read_unlock_bh(&pch->upl);
1517 }
1518
1519 /* Put a 0-length skb in the receive queue as an error indication */
1520 void
1521 ppp_input_error(struct ppp_channel *chan, int code)
1522 {
1523         struct channel *pch = chan->ppp;
1524         struct sk_buff *skb;
1525
1526         if (pch == 0)
1527                 return;
1528
1529         read_lock_bh(&pch->upl);
1530         if (pch->ppp != 0) {
1531                 skb = alloc_skb(0, GFP_ATOMIC);
1532                 if (skb != 0) {
1533                         skb->len = 0;           /* probably unnecessary */
1534                         skb->cb[0] = code;
1535                         ppp_do_recv(pch->ppp, skb, pch);
1536                 }
1537         }
1538         read_unlock_bh(&pch->upl);
1539 }
1540
1541 /*
1542  * We come in here to process a received frame.
1543  * The receive side of the ppp unit is locked.
1544  */
1545 static void
1546 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1547 {
1548         if (skb->len >= 2) {
1549 #ifdef CONFIG_PPP_MULTILINK
1550                 /* XXX do channel-level decompression here */
1551                 if (PPP_PROTO(skb) == PPP_MP)
1552                         ppp_receive_mp_frame(ppp, skb, pch);
1553                 else
1554 #endif /* CONFIG_PPP_MULTILINK */
1555                         ppp_receive_nonmp_frame(ppp, skb);
1556                 return;
1557         }
1558
1559         if (skb->len > 0)
1560                 /* note: a 0-length skb is used as an error indication */
1561                 ++ppp->stats.rx_length_errors;
1562
1563         kfree_skb(skb);
1564         ppp_receive_error(ppp);
1565 }
1566
1567 static void
1568 ppp_receive_error(struct ppp *ppp)
1569 {
1570         ++ppp->stats.rx_errors;
1571         if (ppp->vj != 0)
1572                 slhc_toss(ppp->vj);
1573 }
1574
1575 static void
1576 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1577 {
1578         struct sk_buff *ns;
1579         int proto, len, npi;
1580
1581         /*
1582          * Decompress the frame, if compressed.
1583          * Note that some decompressors need to see uncompressed frames
1584          * that come in as well as compressed frames.
1585          */
1586         if (ppp->rc_state != 0 && (ppp->rstate & SC_DECOMP_RUN)
1587             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1588                 skb = ppp_decompress_frame(ppp, skb);
1589
1590         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1591                 goto err;
1592
1593         proto = PPP_PROTO(skb);
1594         switch (proto) {
1595         case PPP_VJC_COMP:
1596                 /* decompress VJ compressed packets */
1597                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1598                         goto err;
1599
1600                 if (skb_tailroom(skb) < 124) {
1601                         /* copy to a new sk_buff with more tailroom */
1602                         ns = dev_alloc_skb(skb->len + 128);
1603                         if (ns == 0) {
1604                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1605                                 goto err;
1606                         }
1607                         skb_reserve(ns, 2);
1608                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1609                         kfree_skb(skb);
1610                         skb = ns;
1611                 }
1612                 else if (!pskb_may_pull(skb, skb->len))
1613                         goto err;
1614                 else
1615                         skb->ip_summed = CHECKSUM_NONE;
1616
1617                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1618                 if (len <= 0) {
1619                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1620                         goto err;
1621                 }
1622                 len += 2;
1623                 if (len > skb->len)
1624                         skb_put(skb, len - skb->len);
1625                 else if (len < skb->len)
1626                         skb_trim(skb, len);
1627                 proto = PPP_IP;
1628                 break;
1629
1630         case PPP_VJC_UNCOMP:
1631                 if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
1632                         goto err;
1633                 
1634                 /* Until we fix the decompressor need to make sure
1635                  * data portion is linear.
1636                  */
1637                 if (!pskb_may_pull(skb, skb->len)) 
1638                         goto err;
1639
1640                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1641                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1642                         goto err;
1643                 }
1644                 proto = PPP_IP;
1645                 break;
1646
1647         case PPP_CCP:
1648                 ppp_ccp_peek(ppp, skb, 1);
1649                 break;
1650         }
1651
1652         ++ppp->stats.rx_packets;
1653         ppp->stats.rx_bytes += skb->len - 2;
1654
1655         npi = proto_to_npindex(proto);
1656         if (npi < 0) {
1657                 /* control or unknown frame - pass it to pppd */
1658                 skb_queue_tail(&ppp->file.rq, skb);
1659                 /* limit queue length by dropping old frames */
1660                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1661                        && (skb = skb_dequeue(&ppp->file.rq)) != 0)
1662                         kfree_skb(skb);
1663                 /* wake up any process polling or blocking on read */
1664                 wake_up_interruptible(&ppp->file.rwait);
1665
1666         } else {
1667                 /* network protocol frame - give it to the kernel */
1668
1669 #ifdef CONFIG_PPP_FILTER
1670                 /* check if the packet passes the pass and active filters */
1671                 /* the filter instructions are constructed assuming
1672                    a four-byte PPP header on each packet */
1673                 *skb_push(skb, 2) = 0;
1674                 if (ppp->pass_filter
1675                     && sk_run_filter(skb, ppp->pass_filter,
1676                                      ppp->pass_len) == 0) {
1677                         if (ppp->debug & 1)
1678                                 printk(KERN_DEBUG "PPP: inbound frame not passed\n");
1679                         kfree_skb(skb);
1680                         return;
1681                 }
1682                 if (!(ppp->active_filter
1683                       && sk_run_filter(skb, ppp->active_filter,
1684                                        ppp->active_len) == 0))
1685                         ppp->last_recv = jiffies;
1686                 skb_pull(skb, 2);
1687 #else
1688                 ppp->last_recv = jiffies;
1689 #endif /* CONFIG_PPP_FILTER */
1690
1691                 if ((ppp->dev->flags & IFF_UP) == 0
1692                     || ppp->npmode[npi] != NPMODE_PASS) {
1693                         kfree_skb(skb);
1694                 } else {
1695                         /* chop off protocol */
1696                         skb_pull_rcsum(skb, 2);
1697                         skb->dev = ppp->dev;
1698                         skb->protocol = htons(npindex_to_ethertype[npi]);
1699                         skb->mac.raw = skb->data;
1700                         netif_rx(skb);
1701                         ppp->dev->last_rx = jiffies;
1702                 }
1703         }
1704         return;
1705
1706  err:
1707         kfree_skb(skb);
1708         ppp_receive_error(ppp);
1709 }
1710
1711 static struct sk_buff *
1712 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1713 {
1714         int proto = PPP_PROTO(skb);
1715         struct sk_buff *ns;
1716         int len;
1717
1718         /* Until we fix all the decompressor's need to make sure
1719          * data portion is linear.
1720          */
1721         if (!pskb_may_pull(skb, skb->len))
1722                 goto err;
1723
1724         if (proto == PPP_COMP) {
1725                 ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
1726                 if (ns == 0) {
1727                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1728                         goto err;
1729                 }
1730                 /* the decompressor still expects the A/C bytes in the hdr */
1731                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1732                                 skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
1733                 if (len < 0) {
1734                         /* Pass the compressed frame to pppd as an
1735                            error indication. */
1736                         if (len == DECOMP_FATALERROR)
1737                                 ppp->rstate |= SC_DC_FERROR;
1738                         kfree_skb(ns);
1739                         goto err;
1740                 }
1741
1742                 kfree_skb(skb);
1743                 skb = ns;
1744                 skb_put(skb, len);
1745                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1746
1747         } else {
1748                 /* Uncompressed frame - pass to decompressor so it
1749                    can update its dictionary if necessary. */
1750                 if (ppp->rcomp->incomp)
1751                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1752                                            skb->len + 2);
1753         }
1754
1755         return skb;
1756
1757  err:
1758         ppp->rstate |= SC_DC_ERROR;
1759         ppp_receive_error(ppp);
1760         return skb;
1761 }
1762
1763 #ifdef CONFIG_PPP_MULTILINK
1764 /*
1765  * Receive a multilink frame.
1766  * We put it on the reconstruction queue and then pull off
1767  * as many completed frames as we can.
1768  */
1769 static void
1770 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1771 {
1772         u32 mask, seq;
1773         struct channel *ch;
1774         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1775
1776         if (!pskb_may_pull(skb, mphdrlen) || ppp->mrru == 0)
1777                 goto err;               /* no good, throw it away */
1778
1779         /* Decode sequence number and begin/end bits */
1780         if (ppp->flags & SC_MP_SHORTSEQ) {
1781                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1782                 mask = 0xfff;
1783         } else {
1784                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1785                 mask = 0xffffff;
1786         }
1787         skb->BEbits = skb->data[2];
1788         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1789
1790         /*
1791          * Do protocol ID decompression on the first fragment of each packet.
1792          */
1793         if ((skb->BEbits & B) && (skb->data[0] & 1))
1794                 *skb_push(skb, 1) = 0;
1795
1796         /*
1797          * Expand sequence number to 32 bits, making it as close
1798          * as possible to ppp->minseq.
1799          */
1800         seq |= ppp->minseq & ~mask;
1801         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1802                 seq += mask + 1;
1803         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1804                 seq -= mask + 1;        /* should never happen */
1805         skb->sequence = seq;
1806         pch->lastseq = seq;
1807
1808         /*
1809          * If this packet comes before the next one we were expecting,
1810          * drop it.
1811          */
1812         if (seq_before(seq, ppp->nextseq)) {
1813                 kfree_skb(skb);
1814                 ++ppp->stats.rx_dropped;
1815                 ppp_receive_error(ppp);
1816                 return;
1817         }
1818
1819         /*
1820          * Reevaluate minseq, the minimum over all channels of the
1821          * last sequence number received on each channel.  Because of
1822          * the increasing sequence number rule, we know that any fragment
1823          * before `minseq' which hasn't arrived is never going to arrive.
1824          * The list of channels can't change because we have the receive
1825          * side of the ppp unit locked.
1826          */
1827         list_for_each_entry(ch, &ppp->channels, clist) {
1828                 if (seq_before(ch->lastseq, seq))
1829                         seq = ch->lastseq;
1830         }
1831         if (seq_before(ppp->minseq, seq))
1832                 ppp->minseq = seq;
1833
1834         /* Put the fragment on the reconstruction queue */
1835         ppp_mp_insert(ppp, skb);
1836
1837         /* If the queue is getting long, don't wait any longer for packets
1838            before the start of the queue. */
1839         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN
1840             && seq_before(ppp->minseq, ppp->mrq.next->sequence))
1841                 ppp->minseq = ppp->mrq.next->sequence;
1842
1843         /* Pull completed packets off the queue and receive them. */
1844         while ((skb = ppp_mp_reconstruct(ppp)) != 0)
1845                 ppp_receive_nonmp_frame(ppp, skb);
1846
1847         return;
1848
1849  err:
1850         kfree_skb(skb);
1851         ppp_receive_error(ppp);
1852 }
1853
1854 /*
1855  * Insert a fragment on the MP reconstruction queue.
1856  * The queue is ordered by increasing sequence number.
1857  */
1858 static void
1859 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1860 {
1861         struct sk_buff *p;
1862         struct sk_buff_head *list = &ppp->mrq;
1863         u32 seq = skb->sequence;
1864
1865         /* N.B. we don't need to lock the list lock because we have the
1866            ppp unit receive-side lock. */
1867         for (p = list->next; p != (struct sk_buff *)list; p = p->next)
1868                 if (seq_before(seq, p->sequence))
1869                         break;
1870         __skb_insert(skb, p->prev, p, list);
1871 }
1872
1873 /*
1874  * Reconstruct a packet from the MP fragment queue.
1875  * We go through increasing sequence numbers until we find a
1876  * complete packet, or we get to the sequence number for a fragment
1877  * which hasn't arrived but might still do so.
1878  */
1879 struct sk_buff *
1880 ppp_mp_reconstruct(struct ppp *ppp)
1881 {
1882         u32 seq = ppp->nextseq;
1883         u32 minseq = ppp->minseq;
1884         struct sk_buff_head *list = &ppp->mrq;
1885         struct sk_buff *p, *next;
1886         struct sk_buff *head, *tail;
1887         struct sk_buff *skb = NULL;
1888         int lost = 0, len = 0;
1889
1890         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1891                 return NULL;
1892         head = list->next;
1893         tail = NULL;
1894         for (p = head; p != (struct sk_buff *) list; p = next) {
1895                 next = p->next;
1896                 if (seq_before(p->sequence, seq)) {
1897                         /* this can't happen, anyway ignore the skb */
1898                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1899                                p->sequence, seq);
1900                         head = next;
1901                         continue;
1902                 }
1903                 if (p->sequence != seq) {
1904                         /* Fragment `seq' is missing.  If it is after
1905                            minseq, it might arrive later, so stop here. */
1906                         if (seq_after(seq, minseq))
1907                                 break;
1908                         /* Fragment `seq' is lost, keep going. */
1909                         lost = 1;
1910                         seq = seq_before(minseq, p->sequence)?
1911                                 minseq + 1: p->sequence;
1912                         next = p;
1913                         continue;
1914                 }
1915
1916                 /*
1917                  * At this point we know that all the fragments from
1918                  * ppp->nextseq to seq are either present or lost.
1919                  * Also, there are no complete packets in the queue
1920                  * that have no missing fragments and end before this
1921                  * fragment.
1922                  */
1923
1924                 /* B bit set indicates this fragment starts a packet */
1925                 if (p->BEbits & B) {
1926                         head = p;
1927                         lost = 0;
1928                         len = 0;
1929                 }
1930
1931                 len += p->len;
1932
1933                 /* Got a complete packet yet? */
1934                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1935                         if (len > ppp->mrru + 2) {
1936                                 ++ppp->stats.rx_length_errors;
1937                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1938                                        " is too long (%d)\n", len);
1939                         } else if (p == head) {
1940                                 /* fragment is complete packet - reuse skb */
1941                                 tail = p;
1942                                 skb = skb_get(p);
1943                                 break;
1944                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1945                                 ++ppp->stats.rx_missed_errors;
1946                                 printk(KERN_DEBUG "PPP: no memory for "
1947                                        "reconstructed packet");
1948                         } else {
1949                                 tail = p;
1950                                 break;
1951                         }
1952                         ppp->nextseq = seq + 1;
1953                 }
1954
1955                 /*
1956                  * If this is the ending fragment of a packet,
1957                  * and we haven't found a complete valid packet yet,
1958                  * we can discard up to and including this fragment.
1959                  */
1960                 if (p->BEbits & E)
1961                         head = next;
1962
1963                 ++seq;
1964         }
1965
1966         /* If we have a complete packet, copy it all into one skb. */
1967         if (tail != NULL) {
1968                 /* If we have discarded any fragments,
1969                    signal a receive error. */
1970                 if (head->sequence != ppp->nextseq) {
1971                         if (ppp->debug & 1)
1972                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1973                                        ppp->nextseq, head->sequence-1);
1974                         ++ppp->stats.rx_dropped;
1975                         ppp_receive_error(ppp);
1976                 }
1977
1978                 if (head != tail)
1979                         /* copy to a single skb */
1980                         for (p = head; p != tail->next; p = p->next)
1981                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1982                 ppp->nextseq = tail->sequence + 1;
1983                 head = tail->next;
1984         }
1985
1986         /* Discard all the skbuffs that we have copied the data out of
1987            or that we can't use. */
1988         while ((p = list->next) != head) {
1989                 __skb_unlink(p, list);
1990                 kfree_skb(p);
1991         }
1992
1993         return skb;
1994 }
1995 #endif /* CONFIG_PPP_MULTILINK */
1996
1997 /*
1998  * Channel interface.
1999  */
2000
2001 /*
2002  * Create a new, unattached ppp channel.
2003  */
2004 int
2005 ppp_register_channel(struct ppp_channel *chan)
2006 {
2007         struct channel *pch;
2008
2009         pch = kmalloc(sizeof(struct channel), GFP_KERNEL);
2010         if (pch == 0)
2011                 return -ENOMEM;
2012         memset(pch, 0, sizeof(struct channel));
2013         pch->ppp = NULL;
2014         pch->chan = chan;
2015         chan->ppp = pch;
2016         init_ppp_file(&pch->file, CHANNEL);
2017         pch->file.hdrlen = chan->hdrlen;
2018 #ifdef CONFIG_PPP_MULTILINK
2019         pch->lastseq = -1;
2020 #endif /* CONFIG_PPP_MULTILINK */
2021         init_rwsem(&pch->chan_sem);
2022         spin_lock_init(&pch->downl);
2023         rwlock_init(&pch->upl);
2024         spin_lock_bh(&all_channels_lock);
2025         pch->file.index = ++last_channel_index;
2026         list_add(&pch->list, &new_channels);
2027         atomic_inc(&channel_count);
2028         spin_unlock_bh(&all_channels_lock);
2029         return 0;
2030 }
2031
2032 /*
2033  * Return the index of a channel.
2034  */
2035 int ppp_channel_index(struct ppp_channel *chan)
2036 {
2037         struct channel *pch = chan->ppp;
2038
2039         if (pch != 0)
2040                 return pch->file.index;
2041         return -1;
2042 }
2043
2044 /*
2045  * Return the PPP unit number to which a channel is connected.
2046  */
2047 int ppp_unit_number(struct ppp_channel *chan)
2048 {
2049         struct channel *pch = chan->ppp;
2050         int unit = -1;
2051
2052         if (pch != 0) {
2053                 read_lock_bh(&pch->upl);
2054                 if (pch->ppp != 0)
2055                         unit = pch->ppp->file.index;
2056                 read_unlock_bh(&pch->upl);
2057         }
2058         return unit;
2059 }
2060
2061 /*
2062  * Disconnect a channel from the generic layer.
2063  * This must be called in process context.
2064  */
2065 void
2066 ppp_unregister_channel(struct ppp_channel *chan)
2067 {
2068         struct channel *pch = chan->ppp;
2069
2070         if (pch == 0)
2071                 return;         /* should never happen */
2072         chan->ppp = NULL;
2073
2074         /*
2075          * This ensures that we have returned from any calls into the
2076          * the channel's start_xmit or ioctl routine before we proceed.
2077          */
2078         down_write(&pch->chan_sem);
2079         spin_lock_bh(&pch->downl);
2080         pch->chan = NULL;
2081         spin_unlock_bh(&pch->downl);
2082         up_write(&pch->chan_sem);
2083         ppp_disconnect_channel(pch);
2084         spin_lock_bh(&all_channels_lock);
2085         list_del(&pch->list);
2086         spin_unlock_bh(&all_channels_lock);
2087         pch->file.dead = 1;
2088         wake_up_interruptible(&pch->file.rwait);
2089         if (atomic_dec_and_test(&pch->file.refcnt))
2090                 ppp_destroy_channel(pch);
2091 }
2092
2093 /*
2094  * Callback from a channel when it can accept more to transmit.
2095  * This should be called at BH/softirq level, not interrupt level.
2096  */
2097 void
2098 ppp_output_wakeup(struct ppp_channel *chan)
2099 {
2100         struct channel *pch = chan->ppp;
2101
2102         if (pch == 0)
2103                 return;
2104         ppp_channel_push(pch);
2105 }
2106
2107 /*
2108  * Compression control.
2109  */
2110
2111 /* Process the PPPIOCSCOMPRESS ioctl. */
2112 static int
2113 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2114 {
2115         int err;
2116         struct compressor *cp, *ocomp;
2117         struct ppp_option_data data;
2118         void *state, *ostate;
2119         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2120
2121         err = -EFAULT;
2122         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2123             || (data.length <= CCP_MAX_OPTION_LENGTH
2124                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2125                 goto out;
2126         err = -EINVAL;
2127         if (data.length > CCP_MAX_OPTION_LENGTH
2128             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2129                 goto out;
2130
2131         cp = find_compressor(ccp_option[0]);
2132 #ifdef CONFIG_KMOD
2133         if (cp == 0) {
2134                 request_module("ppp-compress-%d", ccp_option[0]);
2135                 cp = find_compressor(ccp_option[0]);
2136         }
2137 #endif /* CONFIG_KMOD */
2138         if (cp == 0)
2139                 goto out;
2140
2141         err = -ENOBUFS;
2142         if (data.transmit) {
2143                 state = cp->comp_alloc(ccp_option, data.length);
2144                 if (state != 0) {
2145                         ppp_xmit_lock(ppp);
2146                         ppp->xstate &= ~SC_COMP_RUN;
2147                         ocomp = ppp->xcomp;
2148                         ostate = ppp->xc_state;
2149                         ppp->xcomp = cp;
2150                         ppp->xc_state = state;
2151                         ppp_xmit_unlock(ppp);
2152                         if (ostate != 0) {
2153                                 ocomp->comp_free(ostate);
2154                                 module_put(ocomp->owner);
2155                         }
2156                         err = 0;
2157                 } else
2158                         module_put(cp->owner);
2159
2160         } else {
2161                 state = cp->decomp_alloc(ccp_option, data.length);
2162                 if (state != 0) {
2163                         ppp_recv_lock(ppp);
2164                         ppp->rstate &= ~SC_DECOMP_RUN;
2165                         ocomp = ppp->rcomp;
2166                         ostate = ppp->rc_state;
2167                         ppp->rcomp = cp;
2168                         ppp->rc_state = state;
2169                         ppp_recv_unlock(ppp);
2170                         if (ostate != 0) {
2171                                 ocomp->decomp_free(ostate);
2172                                 module_put(ocomp->owner);
2173                         }
2174                         err = 0;
2175                 } else
2176                         module_put(cp->owner);
2177         }
2178
2179  out:
2180         return err;
2181 }
2182
2183 /*
2184  * Look at a CCP packet and update our state accordingly.
2185  * We assume the caller has the xmit or recv path locked.
2186  */
2187 static void
2188 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2189 {
2190         unsigned char *dp;
2191         int len;
2192
2193         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2194                 return; /* no header */
2195         dp = skb->data + 2;
2196
2197         switch (CCP_CODE(dp)) {
2198         case CCP_CONFREQ:
2199
2200                 /* A ConfReq starts negotiation of compression 
2201                  * in one direction of transmission,
2202                  * and hence brings it down...but which way?
2203                  *
2204                  * Remember:
2205                  * A ConfReq indicates what the sender would like to receive
2206                  */
2207                 if(inbound)
2208                         /* He is proposing what I should send */
2209                         ppp->xstate &= ~SC_COMP_RUN;
2210                 else    
2211                         /* I am proposing to what he should send */
2212                         ppp->rstate &= ~SC_DECOMP_RUN;
2213                 
2214                 break;
2215                 
2216         case CCP_TERMREQ:
2217         case CCP_TERMACK:
2218                 /*
2219                  * CCP is going down, both directions of transmission 
2220                  */
2221                 ppp->rstate &= ~SC_DECOMP_RUN;
2222                 ppp->xstate &= ~SC_COMP_RUN;
2223                 break;
2224
2225         case CCP_CONFACK:
2226                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2227                         break;
2228                 len = CCP_LENGTH(dp);
2229                 if (!pskb_may_pull(skb, len + 2))
2230                         return;         /* too short */
2231                 dp += CCP_HDRLEN;
2232                 len -= CCP_HDRLEN;
2233                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2234                         break;
2235                 if (inbound) {
2236                         /* we will start receiving compressed packets */
2237                         if (ppp->rc_state == 0)
2238                                 break;
2239                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2240                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2241                                 ppp->rstate |= SC_DECOMP_RUN;
2242                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2243                         }
2244                 } else {
2245                         /* we will soon start sending compressed packets */
2246                         if (ppp->xc_state == 0)
2247                                 break;
2248                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2249                                         ppp->file.index, 0, ppp->debug))
2250                                 ppp->xstate |= SC_COMP_RUN;
2251                 }
2252                 break;
2253
2254         case CCP_RESETACK:
2255                 /* reset the [de]compressor */
2256                 if ((ppp->flags & SC_CCP_UP) == 0)
2257                         break;
2258                 if (inbound) {
2259                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2260                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2261                                 ppp->rstate &= ~SC_DC_ERROR;
2262                         }
2263                 } else {
2264                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2265                                 ppp->xcomp->comp_reset(ppp->xc_state);
2266                 }
2267                 break;
2268         }
2269 }
2270
2271 /* Free up compression resources. */
2272 static void
2273 ppp_ccp_closed(struct ppp *ppp)
2274 {
2275         void *xstate, *rstate;
2276         struct compressor *xcomp, *rcomp;
2277
2278         ppp_lock(ppp);
2279         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2280         ppp->xstate = 0;
2281         xcomp = ppp->xcomp;
2282         xstate = ppp->xc_state;
2283         ppp->xc_state = NULL;
2284         ppp->rstate = 0;
2285         rcomp = ppp->rcomp;
2286         rstate = ppp->rc_state;
2287         ppp->rc_state = NULL;
2288         ppp_unlock(ppp);
2289
2290         if (xstate) {
2291                 xcomp->comp_free(xstate);
2292                 module_put(xcomp->owner);
2293         }
2294         if (rstate) {
2295                 rcomp->decomp_free(rstate);
2296                 module_put(rcomp->owner);
2297         }
2298 }
2299
2300 /* List of compressors. */
2301 static LIST_HEAD(compressor_list);
2302 static DEFINE_SPINLOCK(compressor_list_lock);
2303
2304 struct compressor_entry {
2305         struct list_head list;
2306         struct compressor *comp;
2307 };
2308
2309 static struct compressor_entry *
2310 find_comp_entry(int proto)
2311 {
2312         struct compressor_entry *ce;
2313
2314         list_for_each_entry(ce, &compressor_list, list) {
2315                 if (ce->comp->compress_proto == proto)
2316                         return ce;
2317         }
2318         return NULL;
2319 }
2320
2321 /* Register a compressor */
2322 int
2323 ppp_register_compressor(struct compressor *cp)
2324 {
2325         struct compressor_entry *ce;
2326         int ret;
2327         spin_lock(&compressor_list_lock);
2328         ret = -EEXIST;
2329         if (find_comp_entry(cp->compress_proto) != 0)
2330                 goto out;
2331         ret = -ENOMEM;
2332         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2333         if (ce == 0)
2334                 goto out;
2335         ret = 0;
2336         ce->comp = cp;
2337         list_add(&ce->list, &compressor_list);
2338  out:
2339         spin_unlock(&compressor_list_lock);
2340         return ret;
2341 }
2342
2343 /* Unregister a compressor */
2344 void
2345 ppp_unregister_compressor(struct compressor *cp)
2346 {
2347         struct compressor_entry *ce;
2348
2349         spin_lock(&compressor_list_lock);
2350         ce = find_comp_entry(cp->compress_proto);
2351         if (ce != 0 && ce->comp == cp) {
2352                 list_del(&ce->list);
2353                 kfree(ce);
2354         }
2355         spin_unlock(&compressor_list_lock);
2356 }
2357
2358 /* Find a compressor. */
2359 static struct compressor *
2360 find_compressor(int type)
2361 {
2362         struct compressor_entry *ce;
2363         struct compressor *cp = NULL;
2364
2365         spin_lock(&compressor_list_lock);
2366         ce = find_comp_entry(type);
2367         if (ce != 0) {
2368                 cp = ce->comp;
2369                 if (!try_module_get(cp->owner))
2370                         cp = NULL;
2371         }
2372         spin_unlock(&compressor_list_lock);
2373         return cp;
2374 }
2375
2376 /*
2377  * Miscelleneous stuff.
2378  */
2379
2380 static void
2381 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2382 {
2383         struct slcompress *vj = ppp->vj;
2384
2385         memset(st, 0, sizeof(*st));
2386         st->p.ppp_ipackets = ppp->stats.rx_packets;
2387         st->p.ppp_ierrors = ppp->stats.rx_errors;
2388         st->p.ppp_ibytes = ppp->stats.rx_bytes;
2389         st->p.ppp_opackets = ppp->stats.tx_packets;
2390         st->p.ppp_oerrors = ppp->stats.tx_errors;
2391         st->p.ppp_obytes = ppp->stats.tx_bytes;
2392         if (vj == 0)
2393                 return;
2394         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2395         st->vj.vjs_compressed = vj->sls_o_compressed;
2396         st->vj.vjs_searches = vj->sls_o_searches;
2397         st->vj.vjs_misses = vj->sls_o_misses;
2398         st->vj.vjs_errorin = vj->sls_i_error;
2399         st->vj.vjs_tossed = vj->sls_i_tossed;
2400         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2401         st->vj.vjs_compressedin = vj->sls_i_compressed;
2402 }
2403
2404 /*
2405  * Stuff for handling the lists of ppp units and channels
2406  * and for initialization.
2407  */
2408
2409 /*
2410  * Create a new ppp interface unit.  Fails if it can't allocate memory
2411  * or if there is already a unit with the requested number.
2412  * unit == -1 means allocate a new number.
2413  */
2414 static struct ppp *
2415 ppp_create_interface(int unit, int *retp)
2416 {
2417         struct ppp *ppp;
2418         struct net_device *dev = NULL;
2419         int ret = -ENOMEM;
2420         int i;
2421
2422         ppp = kmalloc(sizeof(struct ppp), GFP_KERNEL);
2423         if (!ppp)
2424                 goto out;
2425         dev = alloc_netdev(0, "", ppp_setup);
2426         if (!dev)
2427                 goto out1;
2428         memset(ppp, 0, sizeof(struct ppp));
2429
2430         ppp->mru = PPP_MRU;
2431         init_ppp_file(&ppp->file, INTERFACE);
2432         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2433         for (i = 0; i < NUM_NP; ++i)
2434                 ppp->npmode[i] = NPMODE_PASS;
2435         INIT_LIST_HEAD(&ppp->channels);
2436         spin_lock_init(&ppp->rlock);
2437         spin_lock_init(&ppp->wlock);
2438 #ifdef CONFIG_PPP_MULTILINK
2439         ppp->minseq = -1;
2440         skb_queue_head_init(&ppp->mrq);
2441 #endif /* CONFIG_PPP_MULTILINK */
2442         ppp->dev = dev;
2443         dev->priv = ppp;
2444
2445         dev->hard_start_xmit = ppp_start_xmit;
2446         dev->get_stats = ppp_net_stats;
2447         dev->do_ioctl = ppp_net_ioctl;
2448
2449         ret = -EEXIST;
2450         mutex_lock(&all_ppp_mutex);
2451         if (unit < 0)
2452                 unit = cardmap_find_first_free(all_ppp_units);
2453         else if (cardmap_get(all_ppp_units, unit) != NULL)
2454                 goto out2;      /* unit already exists */
2455
2456         /* Initialize the new ppp unit */
2457         ppp->file.index = unit;
2458         sprintf(dev->name, "ppp%d", unit);
2459
2460         ret = register_netdev(dev);
2461         if (ret != 0) {
2462                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2463                        dev->name, ret);
2464                 goto out2;
2465         }
2466
2467         atomic_inc(&ppp_unit_count);
2468         cardmap_set(&all_ppp_units, unit, ppp);
2469         mutex_unlock(&all_ppp_mutex);
2470         *retp = 0;
2471         return ppp;
2472
2473 out2:
2474         mutex_unlock(&all_ppp_mutex);
2475         free_netdev(dev);
2476 out1:
2477         kfree(ppp);
2478 out:
2479         *retp = ret;
2480         return NULL;
2481 }
2482
2483 /*
2484  * Initialize a ppp_file structure.
2485  */
2486 static void
2487 init_ppp_file(struct ppp_file *pf, int kind)
2488 {
2489         pf->kind = kind;
2490         skb_queue_head_init(&pf->xq);
2491         skb_queue_head_init(&pf->rq);
2492         atomic_set(&pf->refcnt, 1);
2493         init_waitqueue_head(&pf->rwait);
2494 }
2495
2496 /*
2497  * Take down a ppp interface unit - called when the owning file
2498  * (the one that created the unit) is closed or detached.
2499  */
2500 static void ppp_shutdown_interface(struct ppp *ppp)
2501 {
2502         struct net_device *dev;
2503
2504         mutex_lock(&all_ppp_mutex);
2505         ppp_lock(ppp);
2506         dev = ppp->dev;
2507         ppp->dev = NULL;
2508         ppp_unlock(ppp);
2509         /* This will call dev_close() for us. */
2510         if (dev) {
2511                 unregister_netdev(dev);
2512                 free_netdev(dev);
2513         }
2514         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2515         ppp->file.dead = 1;
2516         ppp->owner = NULL;
2517         wake_up_interruptible(&ppp->file.rwait);
2518         mutex_unlock(&all_ppp_mutex);
2519 }
2520
2521 /*
2522  * Free the memory used by a ppp unit.  This is only called once
2523  * there are no channels connected to the unit and no file structs
2524  * that reference the unit.
2525  */
2526 static void ppp_destroy_interface(struct ppp *ppp)
2527 {
2528         atomic_dec(&ppp_unit_count);
2529
2530         if (!ppp->file.dead || ppp->n_channels) {
2531                 /* "can't happen" */
2532                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2533                        "n_channels=%d !\n", ppp, ppp->file.dead,
2534                        ppp->n_channels);
2535                 return;
2536         }
2537
2538         ppp_ccp_closed(ppp);
2539         if (ppp->vj) {
2540                 slhc_free(ppp->vj);
2541                 ppp->vj = NULL;
2542         }
2543         skb_queue_purge(&ppp->file.xq);
2544         skb_queue_purge(&ppp->file.rq);
2545 #ifdef CONFIG_PPP_MULTILINK
2546         skb_queue_purge(&ppp->mrq);
2547 #endif /* CONFIG_PPP_MULTILINK */
2548 #ifdef CONFIG_PPP_FILTER
2549         kfree(ppp->pass_filter);
2550         ppp->pass_filter = NULL;
2551         kfree(ppp->active_filter);
2552         ppp->active_filter = NULL;
2553 #endif /* CONFIG_PPP_FILTER */
2554
2555         kfree(ppp);
2556 }
2557
2558 /*
2559  * Locate an existing ppp unit.
2560  * The caller should have locked the all_ppp_mutex.
2561  */
2562 static struct ppp *
2563 ppp_find_unit(int unit)
2564 {
2565         return cardmap_get(all_ppp_units, unit);
2566 }
2567
2568 /*
2569  * Locate an existing ppp channel.
2570  * The caller should have locked the all_channels_lock.
2571  * First we look in the new_channels list, then in the
2572  * all_channels list.  If found in the new_channels list,
2573  * we move it to the all_channels list.  This is for speed
2574  * when we have a lot of channels in use.
2575  */
2576 static struct channel *
2577 ppp_find_channel(int unit)
2578 {
2579         struct channel *pch;
2580
2581         list_for_each_entry(pch, &new_channels, list) {
2582                 if (pch->file.index == unit) {
2583                         list_del(&pch->list);
2584                         list_add(&pch->list, &all_channels);
2585                         return pch;
2586                 }
2587         }
2588         list_for_each_entry(pch, &all_channels, list) {
2589                 if (pch->file.index == unit)
2590                         return pch;
2591         }
2592         return NULL;
2593 }
2594
2595 /*
2596  * Connect a PPP channel to a PPP interface unit.
2597  */
2598 static int
2599 ppp_connect_channel(struct channel *pch, int unit)
2600 {
2601         struct ppp *ppp;
2602         int ret = -ENXIO;
2603         int hdrlen;
2604
2605         mutex_lock(&all_ppp_mutex);
2606         ppp = ppp_find_unit(unit);
2607         if (ppp == 0)
2608                 goto out;
2609         write_lock_bh(&pch->upl);
2610         ret = -EINVAL;
2611         if (pch->ppp != 0)
2612                 goto outl;
2613
2614         ppp_lock(ppp);
2615         if (pch->file.hdrlen > ppp->file.hdrlen)
2616                 ppp->file.hdrlen = pch->file.hdrlen;
2617         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2618         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2619                 ppp->dev->hard_header_len = hdrlen;
2620         list_add_tail(&pch->clist, &ppp->channels);
2621         ++ppp->n_channels;
2622         pch->ppp = ppp;
2623         atomic_inc(&ppp->file.refcnt);
2624         ppp_unlock(ppp);
2625         ret = 0;
2626
2627  outl:
2628         write_unlock_bh(&pch->upl);
2629  out:
2630         mutex_unlock(&all_ppp_mutex);
2631         return ret;
2632 }
2633
2634 /*
2635  * Disconnect a channel from its ppp unit.
2636  */
2637 static int
2638 ppp_disconnect_channel(struct channel *pch)
2639 {
2640         struct ppp *ppp;
2641         int err = -EINVAL;
2642
2643         write_lock_bh(&pch->upl);
2644         ppp = pch->ppp;
2645         pch->ppp = NULL;
2646         write_unlock_bh(&pch->upl);
2647         if (ppp != 0) {
2648                 /* remove it from the ppp unit's list */
2649                 ppp_lock(ppp);
2650                 list_del(&pch->clist);
2651                 if (--ppp->n_channels == 0)
2652                         wake_up_interruptible(&ppp->file.rwait);
2653                 ppp_unlock(ppp);
2654                 if (atomic_dec_and_test(&ppp->file.refcnt))
2655                         ppp_destroy_interface(ppp);
2656                 err = 0;
2657         }
2658         return err;
2659 }
2660
2661 /*
2662  * Free up the resources used by a ppp channel.
2663  */
2664 static void ppp_destroy_channel(struct channel *pch)
2665 {
2666         atomic_dec(&channel_count);
2667
2668         if (!pch->file.dead) {
2669                 /* "can't happen" */
2670                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2671                        pch);
2672                 return;
2673         }
2674         skb_queue_purge(&pch->file.xq);
2675         skb_queue_purge(&pch->file.rq);
2676         kfree(pch);
2677 }
2678
2679 static void __exit ppp_cleanup(void)
2680 {
2681         /* should never happen */
2682         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2683                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2684         cardmap_destroy(&all_ppp_units);
2685         if (unregister_chrdev(PPP_MAJOR, "ppp") != 0)
2686                 printk(KERN_ERR "PPP: failed to unregister PPP device\n");
2687         devfs_remove("ppp");
2688         class_device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2689         class_destroy(ppp_class);
2690 }
2691
2692 /*
2693  * Cardmap implementation.
2694  */
2695 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2696 {
2697         struct cardmap *p;
2698         int i;
2699
2700         for (p = map; p != NULL; ) {
2701                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2702                         return NULL;
2703                 if (p->shift == 0)
2704                         return p->ptr[i];
2705                 nr &= ~(CARDMAP_MASK << p->shift);
2706                 p = p->ptr[i];
2707         }
2708         return NULL;
2709 }
2710
2711 static void cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2712 {
2713         struct cardmap *p;
2714         int i;
2715
2716         p = *pmap;
2717         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2718                 do {
2719                         /* need a new top level */
2720                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2721                         memset(np, 0, sizeof(*np));
2722                         np->ptr[0] = p;
2723                         if (p != NULL) {
2724                                 np->shift = p->shift + CARDMAP_ORDER;
2725                                 p->parent = np;
2726                         } else
2727                                 np->shift = 0;
2728                         p = np;
2729                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2730                 *pmap = p;
2731         }
2732         while (p->shift > 0) {
2733                 i = (nr >> p->shift) & CARDMAP_MASK;
2734                 if (p->ptr[i] == NULL) {
2735                         struct cardmap *np = kmalloc(sizeof(*np), GFP_KERNEL);
2736                         memset(np, 0, sizeof(*np));
2737                         np->shift = p->shift - CARDMAP_ORDER;
2738                         np->parent = p;
2739                         p->ptr[i] = np;
2740                 }
2741                 if (ptr == NULL)
2742                         clear_bit(i, &p->inuse);
2743                 p = p->ptr[i];
2744         }
2745         i = nr & CARDMAP_MASK;
2746         p->ptr[i] = ptr;
2747         if (ptr != NULL)
2748                 set_bit(i, &p->inuse);
2749         else
2750                 clear_bit(i, &p->inuse);
2751 }
2752
2753 static unsigned int cardmap_find_first_free(struct cardmap *map)
2754 {
2755         struct cardmap *p;
2756         unsigned int nr = 0;
2757         int i;
2758
2759         if ((p = map) == NULL)
2760                 return 0;
2761         for (;;) {
2762                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2763                 if (i >= CARDMAP_WIDTH) {
2764                         if (p->parent == NULL)
2765                                 return CARDMAP_WIDTH << p->shift;
2766                         p = p->parent;
2767                         i = (nr >> p->shift) & CARDMAP_MASK;
2768                         set_bit(i, &p->inuse);
2769                         continue;
2770                 }
2771                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2772                 if (p->shift == 0 || p->ptr[i] == NULL)
2773                         return nr;
2774                 p = p->ptr[i];
2775         }
2776 }
2777
2778 static void cardmap_destroy(struct cardmap **pmap)
2779 {
2780         struct cardmap *p, *np;
2781         int i;
2782
2783         for (p = *pmap; p != NULL; p = np) {
2784                 if (p->shift != 0) {
2785                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2786                                 if (p->ptr[i] != NULL)
2787                                         break;
2788                         if (i < CARDMAP_WIDTH) {
2789                                 np = p->ptr[i];
2790                                 p->ptr[i] = NULL;
2791                                 continue;
2792                         }
2793                 }
2794                 np = p->parent;
2795                 kfree(p);
2796         }
2797         *pmap = NULL;
2798 }
2799
2800 /* Module/initialization stuff */
2801
2802 module_init(ppp_init);
2803 module_exit(ppp_cleanup);
2804
2805 EXPORT_SYMBOL(ppp_register_channel);
2806 EXPORT_SYMBOL(ppp_unregister_channel);
2807 EXPORT_SYMBOL(ppp_channel_index);
2808 EXPORT_SYMBOL(ppp_unit_number);
2809 EXPORT_SYMBOL(ppp_input);
2810 EXPORT_SYMBOL(ppp_input_error);
2811 EXPORT_SYMBOL(ppp_output_wakeup);
2812 EXPORT_SYMBOL(ppp_register_compressor);
2813 EXPORT_SYMBOL(ppp_unregister_compressor);
2814 MODULE_LICENSE("GPL");
2815 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2816 MODULE_ALIAS("/dev/ppp");