Merge branch 'core/rcu' into core/rcu-for-linus
[pandora-kernel.git] / drivers / net / ppp_generic.c
1 /*
2  * Generic PPP layer for Linux.
3  *
4  * Copyright 1999-2002 Paul Mackerras.
5  *
6  *  This program is free software; you can redistribute it and/or
7  *  modify it under the terms of the GNU General Public License
8  *  as published by the Free Software Foundation; either version
9  *  2 of the License, or (at your option) any later version.
10  *
11  * The generic PPP layer handles the PPP network interfaces, the
12  * /dev/ppp device, packet and VJ compression, and multilink.
13  * It talks to PPP `channels' via the interface defined in
14  * include/linux/ppp_channel.h.  Channels provide the basic means for
15  * sending and receiving PPP frames on some kind of communications
16  * channel.
17  *
18  * Part of the code in this driver was inspired by the old async-only
19  * PPP driver, written by Michael Callahan and Al Longyear, and
20  * subsequently hacked by Paul Mackerras.
21  *
22  * ==FILEVERSION 20041108==
23  */
24
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/kmod.h>
28 #include <linux/init.h>
29 #include <linux/list.h>
30 #include <linux/netdevice.h>
31 #include <linux/poll.h>
32 #include <linux/ppp_defs.h>
33 #include <linux/filter.h>
34 #include <linux/if_ppp.h>
35 #include <linux/ppp_channel.h>
36 #include <linux/ppp-comp.h>
37 #include <linux/skbuff.h>
38 #include <linux/rtnetlink.h>
39 #include <linux/if_arp.h>
40 #include <linux/ip.h>
41 #include <linux/tcp.h>
42 #include <linux/smp_lock.h>
43 #include <linux/spinlock.h>
44 #include <linux/rwsem.h>
45 #include <linux/stddef.h>
46 #include <linux/device.h>
47 #include <linux/mutex.h>
48 #include <net/slhc_vj.h>
49 #include <asm/atomic.h>
50
51 #define PPP_VERSION     "2.4.2"
52
53 /*
54  * Network protocols we support.
55  */
56 #define NP_IP   0               /* Internet Protocol V4 */
57 #define NP_IPV6 1               /* Internet Protocol V6 */
58 #define NP_IPX  2               /* IPX protocol */
59 #define NP_AT   3               /* Appletalk protocol */
60 #define NP_MPLS_UC 4            /* MPLS unicast */
61 #define NP_MPLS_MC 5            /* MPLS multicast */
62 #define NUM_NP  6               /* Number of NPs. */
63
64 #define MPHDRLEN        6       /* multilink protocol header length */
65 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
66 #define MIN_FRAG_SIZE   64
67
68 /*
69  * An instance of /dev/ppp can be associated with either a ppp
70  * interface unit or a ppp channel.  In both cases, file->private_data
71  * points to one of these.
72  */
73 struct ppp_file {
74         enum {
75                 INTERFACE=1, CHANNEL
76         }               kind;
77         struct sk_buff_head xq;         /* pppd transmit queue */
78         struct sk_buff_head rq;         /* receive queue for pppd */
79         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
80         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
81         int             hdrlen;         /* space to leave for headers */
82         int             index;          /* interface unit / channel number */
83         int             dead;           /* unit/channel has been shut down */
84 };
85
86 #define PF_TO_X(pf, X)          container_of(pf, X, file)
87
88 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
89 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
90
91 /*
92  * Data structure describing one ppp unit.
93  * A ppp unit corresponds to a ppp network interface device
94  * and represents a multilink bundle.
95  * It can have 0 or more ppp channels connected to it.
96  */
97 struct ppp {
98         struct ppp_file file;           /* stuff for read/write/poll 0 */
99         struct file     *owner;         /* file that owns this unit 48 */
100         struct list_head channels;      /* list of attached channels 4c */
101         int             n_channels;     /* how many channels are attached 54 */
102         spinlock_t      rlock;          /* lock for receive side 58 */
103         spinlock_t      wlock;          /* lock for transmit side 5c */
104         int             mru;            /* max receive unit 60 */
105         unsigned int    flags;          /* control bits 64 */
106         unsigned int    xstate;         /* transmit state bits 68 */
107         unsigned int    rstate;         /* receive state bits 6c */
108         int             debug;          /* debug flags 70 */
109         struct slcompress *vj;          /* state for VJ header compression */
110         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
111         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
112         struct compressor *xcomp;       /* transmit packet compressor 8c */
113         void            *xc_state;      /* its internal state 90 */
114         struct compressor *rcomp;       /* receive decompressor 94 */
115         void            *rc_state;      /* its internal state 98 */
116         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
117         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
118         struct net_device *dev;         /* network interface device a4 */
119 #ifdef CONFIG_PPP_MULTILINK
120         int             nxchan;         /* next channel to send something on */
121         u32             nxseq;          /* next sequence number to send */
122         int             mrru;           /* MP: max reconst. receive unit */
123         u32             nextseq;        /* MP: seq no of next packet */
124         u32             minseq;         /* MP: min of most recent seqnos */
125         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
126 #endif /* CONFIG_PPP_MULTILINK */
127 #ifdef CONFIG_PPP_FILTER
128         struct sock_filter *pass_filter;        /* filter for packets to pass */
129         struct sock_filter *active_filter;/* filter for pkts to reset idle */
130         unsigned pass_len, active_len;
131 #endif /* CONFIG_PPP_FILTER */
132 };
133
134 /*
135  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
136  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
137  * SC_MUST_COMP
138  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
139  * Bits in xstate: SC_COMP_RUN
140  */
141 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
142                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
143                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
144
145 /*
146  * Private data structure for each channel.
147  * This includes the data structure used for multilink.
148  */
149 struct channel {
150         struct ppp_file file;           /* stuff for read/write/poll */
151         struct list_head list;          /* link in all/new_channels list */
152         struct ppp_channel *chan;       /* public channel data structure */
153         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
154         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
155         struct ppp      *ppp;           /* ppp unit we're connected to */
156         struct list_head clist;         /* link in list of channels per unit */
157         rwlock_t        upl;            /* protects `ppp' */
158 #ifdef CONFIG_PPP_MULTILINK
159         u8              avail;          /* flag used in multilink stuff */
160         u8              had_frag;       /* >= 1 fragments have been sent */
161         u32             lastseq;        /* MP: last sequence # received */
162 #endif /* CONFIG_PPP_MULTILINK */
163 };
164
165 /*
166  * SMP locking issues:
167  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
168  * list and the ppp.n_channels field, you need to take both locks
169  * before you modify them.
170  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
171  * channel.downl.
172  */
173
174 /*
175  * A cardmap represents a mapping from unsigned integers to pointers,
176  * and provides a fast "find lowest unused number" operation.
177  * It uses a broad (32-way) tree with a bitmap at each level.
178  * It is designed to be space-efficient for small numbers of entries
179  * and time-efficient for large numbers of entries.
180  */
181 #define CARDMAP_ORDER   5
182 #define CARDMAP_WIDTH   (1U << CARDMAP_ORDER)
183 #define CARDMAP_MASK    (CARDMAP_WIDTH - 1)
184
185 struct cardmap {
186         int shift;
187         unsigned long inuse;
188         struct cardmap *parent;
189         void *ptr[CARDMAP_WIDTH];
190 };
191 static void *cardmap_get(struct cardmap *map, unsigned int nr);
192 static int cardmap_set(struct cardmap **map, unsigned int nr, void *ptr);
193 static unsigned int cardmap_find_first_free(struct cardmap *map);
194 static void cardmap_destroy(struct cardmap **map);
195
196 /*
197  * all_ppp_mutex protects the all_ppp_units mapping.
198  * It also ensures that finding a ppp unit in the all_ppp_units map
199  * and updating its file.refcnt field is atomic.
200  */
201 static DEFINE_MUTEX(all_ppp_mutex);
202 static struct cardmap *all_ppp_units;
203 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
204
205 /*
206  * all_channels_lock protects all_channels and last_channel_index,
207  * and the atomicity of find a channel and updating its file.refcnt
208  * field.
209  */
210 static DEFINE_SPINLOCK(all_channels_lock);
211 static LIST_HEAD(all_channels);
212 static LIST_HEAD(new_channels);
213 static int last_channel_index;
214 static atomic_t channel_count = ATOMIC_INIT(0);
215
216 /* Get the PPP protocol number from a skb */
217 #define PPP_PROTO(skb)  (((skb)->data[0] << 8) + (skb)->data[1])
218
219 /* We limit the length of ppp->file.rq to this (arbitrary) value */
220 #define PPP_MAX_RQLEN   32
221
222 /*
223  * Maximum number of multilink fragments queued up.
224  * This has to be large enough to cope with the maximum latency of
225  * the slowest channel relative to the others.  Strictly it should
226  * depend on the number of channels and their characteristics.
227  */
228 #define PPP_MP_MAX_QLEN 128
229
230 /* Multilink header bits. */
231 #define B       0x80            /* this fragment begins a packet */
232 #define E       0x40            /* this fragment ends a packet */
233
234 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
235 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
236 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
237
238 /* Prototypes. */
239 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
240                                 unsigned int cmd, unsigned long arg);
241 static void ppp_xmit_process(struct ppp *ppp);
242 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
243 static void ppp_push(struct ppp *ppp);
244 static void ppp_channel_push(struct channel *pch);
245 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
246                               struct channel *pch);
247 static void ppp_receive_error(struct ppp *ppp);
248 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
249 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
250                                             struct sk_buff *skb);
251 #ifdef CONFIG_PPP_MULTILINK
252 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
253                                 struct channel *pch);
254 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
255 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
256 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
257 #endif /* CONFIG_PPP_MULTILINK */
258 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
259 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
260 static void ppp_ccp_closed(struct ppp *ppp);
261 static struct compressor *find_compressor(int type);
262 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
263 static struct ppp *ppp_create_interface(int unit, int *retp);
264 static void init_ppp_file(struct ppp_file *pf, int kind);
265 static void ppp_shutdown_interface(struct ppp *ppp);
266 static void ppp_destroy_interface(struct ppp *ppp);
267 static struct ppp *ppp_find_unit(int unit);
268 static struct channel *ppp_find_channel(int unit);
269 static int ppp_connect_channel(struct channel *pch, int unit);
270 static int ppp_disconnect_channel(struct channel *pch);
271 static void ppp_destroy_channel(struct channel *pch);
272
273 static struct class *ppp_class;
274
275 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
276 static inline int proto_to_npindex(int proto)
277 {
278         switch (proto) {
279         case PPP_IP:
280                 return NP_IP;
281         case PPP_IPV6:
282                 return NP_IPV6;
283         case PPP_IPX:
284                 return NP_IPX;
285         case PPP_AT:
286                 return NP_AT;
287         case PPP_MPLS_UC:
288                 return NP_MPLS_UC;
289         case PPP_MPLS_MC:
290                 return NP_MPLS_MC;
291         }
292         return -EINVAL;
293 }
294
295 /* Translates an NP index into a PPP protocol number */
296 static const int npindex_to_proto[NUM_NP] = {
297         PPP_IP,
298         PPP_IPV6,
299         PPP_IPX,
300         PPP_AT,
301         PPP_MPLS_UC,
302         PPP_MPLS_MC,
303 };
304
305 /* Translates an ethertype into an NP index */
306 static inline int ethertype_to_npindex(int ethertype)
307 {
308         switch (ethertype) {
309         case ETH_P_IP:
310                 return NP_IP;
311         case ETH_P_IPV6:
312                 return NP_IPV6;
313         case ETH_P_IPX:
314                 return NP_IPX;
315         case ETH_P_PPPTALK:
316         case ETH_P_ATALK:
317                 return NP_AT;
318         case ETH_P_MPLS_UC:
319                 return NP_MPLS_UC;
320         case ETH_P_MPLS_MC:
321                 return NP_MPLS_MC;
322         }
323         return -1;
324 }
325
326 /* Translates an NP index into an ethertype */
327 static const int npindex_to_ethertype[NUM_NP] = {
328         ETH_P_IP,
329         ETH_P_IPV6,
330         ETH_P_IPX,
331         ETH_P_PPPTALK,
332         ETH_P_MPLS_UC,
333         ETH_P_MPLS_MC,
334 };
335
336 /*
337  * Locking shorthand.
338  */
339 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
340 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
341 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
342 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
343 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
344                                      ppp_recv_lock(ppp); } while (0)
345 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
346                                      ppp_xmit_unlock(ppp); } while (0)
347
348 /*
349  * /dev/ppp device routines.
350  * The /dev/ppp device is used by pppd to control the ppp unit.
351  * It supports the read, write, ioctl and poll functions.
352  * Open instances of /dev/ppp can be in one of three states:
353  * unattached, attached to a ppp unit, or attached to a ppp channel.
354  */
355 static int ppp_open(struct inode *inode, struct file *file)
356 {
357         cycle_kernel_lock();
358         /*
359          * This could (should?) be enforced by the permissions on /dev/ppp.
360          */
361         if (!capable(CAP_NET_ADMIN))
362                 return -EPERM;
363         return 0;
364 }
365
366 static int ppp_release(struct inode *inode, struct file *file)
367 {
368         struct ppp_file *pf = file->private_data;
369         struct ppp *ppp;
370
371         if (pf) {
372                 file->private_data = NULL;
373                 if (pf->kind == INTERFACE) {
374                         ppp = PF_TO_PPP(pf);
375                         if (file == ppp->owner)
376                                 ppp_shutdown_interface(ppp);
377                 }
378                 if (atomic_dec_and_test(&pf->refcnt)) {
379                         switch (pf->kind) {
380                         case INTERFACE:
381                                 ppp_destroy_interface(PF_TO_PPP(pf));
382                                 break;
383                         case CHANNEL:
384                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
385                                 break;
386                         }
387                 }
388         }
389         return 0;
390 }
391
392 static ssize_t ppp_read(struct file *file, char __user *buf,
393                         size_t count, loff_t *ppos)
394 {
395         struct ppp_file *pf = file->private_data;
396         DECLARE_WAITQUEUE(wait, current);
397         ssize_t ret;
398         struct sk_buff *skb = NULL;
399
400         ret = count;
401
402         if (!pf)
403                 return -ENXIO;
404         add_wait_queue(&pf->rwait, &wait);
405         for (;;) {
406                 set_current_state(TASK_INTERRUPTIBLE);
407                 skb = skb_dequeue(&pf->rq);
408                 if (skb)
409                         break;
410                 ret = 0;
411                 if (pf->dead)
412                         break;
413                 if (pf->kind == INTERFACE) {
414                         /*
415                          * Return 0 (EOF) on an interface that has no
416                          * channels connected, unless it is looping
417                          * network traffic (demand mode).
418                          */
419                         struct ppp *ppp = PF_TO_PPP(pf);
420                         if (ppp->n_channels == 0
421                             && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
422                                 break;
423                 }
424                 ret = -EAGAIN;
425                 if (file->f_flags & O_NONBLOCK)
426                         break;
427                 ret = -ERESTARTSYS;
428                 if (signal_pending(current))
429                         break;
430                 schedule();
431         }
432         set_current_state(TASK_RUNNING);
433         remove_wait_queue(&pf->rwait, &wait);
434
435         if (!skb)
436                 goto out;
437
438         ret = -EOVERFLOW;
439         if (skb->len > count)
440                 goto outf;
441         ret = -EFAULT;
442         if (copy_to_user(buf, skb->data, skb->len))
443                 goto outf;
444         ret = skb->len;
445
446  outf:
447         kfree_skb(skb);
448  out:
449         return ret;
450 }
451
452 static ssize_t ppp_write(struct file *file, const char __user *buf,
453                          size_t count, loff_t *ppos)
454 {
455         struct ppp_file *pf = file->private_data;
456         struct sk_buff *skb;
457         ssize_t ret;
458
459         if (!pf)
460                 return -ENXIO;
461         ret = -ENOMEM;
462         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
463         if (!skb)
464                 goto out;
465         skb_reserve(skb, pf->hdrlen);
466         ret = -EFAULT;
467         if (copy_from_user(skb_put(skb, count), buf, count)) {
468                 kfree_skb(skb);
469                 goto out;
470         }
471
472         skb_queue_tail(&pf->xq, skb);
473
474         switch (pf->kind) {
475         case INTERFACE:
476                 ppp_xmit_process(PF_TO_PPP(pf));
477                 break;
478         case CHANNEL:
479                 ppp_channel_push(PF_TO_CHANNEL(pf));
480                 break;
481         }
482
483         ret = count;
484
485  out:
486         return ret;
487 }
488
489 /* No kernel lock - fine */
490 static unsigned int ppp_poll(struct file *file, poll_table *wait)
491 {
492         struct ppp_file *pf = file->private_data;
493         unsigned int mask;
494
495         if (!pf)
496                 return 0;
497         poll_wait(file, &pf->rwait, wait);
498         mask = POLLOUT | POLLWRNORM;
499         if (skb_peek(&pf->rq))
500                 mask |= POLLIN | POLLRDNORM;
501         if (pf->dead)
502                 mask |= POLLHUP;
503         else if (pf->kind == INTERFACE) {
504                 /* see comment in ppp_read */
505                 struct ppp *ppp = PF_TO_PPP(pf);
506                 if (ppp->n_channels == 0
507                     && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
508                         mask |= POLLIN | POLLRDNORM;
509         }
510
511         return mask;
512 }
513
514 #ifdef CONFIG_PPP_FILTER
515 static int get_filter(void __user *arg, struct sock_filter **p)
516 {
517         struct sock_fprog uprog;
518         struct sock_filter *code = NULL;
519         int len, err;
520
521         if (copy_from_user(&uprog, arg, sizeof(uprog)))
522                 return -EFAULT;
523
524         if (!uprog.len) {
525                 *p = NULL;
526                 return 0;
527         }
528
529         len = uprog.len * sizeof(struct sock_filter);
530         code = kmalloc(len, GFP_KERNEL);
531         if (code == NULL)
532                 return -ENOMEM;
533
534         if (copy_from_user(code, uprog.filter, len)) {
535                 kfree(code);
536                 return -EFAULT;
537         }
538
539         err = sk_chk_filter(code, uprog.len);
540         if (err) {
541                 kfree(code);
542                 return err;
543         }
544
545         *p = code;
546         return uprog.len;
547 }
548 #endif /* CONFIG_PPP_FILTER */
549
550 static int ppp_ioctl(struct inode *inode, struct file *file,
551                      unsigned int cmd, unsigned long arg)
552 {
553         struct ppp_file *pf = file->private_data;
554         struct ppp *ppp;
555         int err = -EFAULT, val, val2, i;
556         struct ppp_idle idle;
557         struct npioctl npi;
558         int unit, cflags;
559         struct slcompress *vj;
560         void __user *argp = (void __user *)arg;
561         int __user *p = argp;
562
563         if (!pf)
564                 return ppp_unattached_ioctl(pf, file, cmd, arg);
565
566         if (cmd == PPPIOCDETACH) {
567                 /*
568                  * We have to be careful here... if the file descriptor
569                  * has been dup'd, we could have another process in the
570                  * middle of a poll using the same file *, so we had
571                  * better not free the interface data structures -
572                  * instead we fail the ioctl.  Even in this case, we
573                  * shut down the interface if we are the owner of it.
574                  * Actually, we should get rid of PPPIOCDETACH, userland
575                  * (i.e. pppd) could achieve the same effect by closing
576                  * this fd and reopening /dev/ppp.
577                  */
578                 err = -EINVAL;
579                 if (pf->kind == INTERFACE) {
580                         ppp = PF_TO_PPP(pf);
581                         if (file == ppp->owner)
582                                 ppp_shutdown_interface(ppp);
583                 }
584                 if (atomic_read(&file->f_count) <= 2) {
585                         ppp_release(inode, file);
586                         err = 0;
587                 } else
588                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%d\n",
589                                atomic_read(&file->f_count));
590                 return err;
591         }
592
593         if (pf->kind == CHANNEL) {
594                 struct channel *pch = PF_TO_CHANNEL(pf);
595                 struct ppp_channel *chan;
596
597                 switch (cmd) {
598                 case PPPIOCCONNECT:
599                         if (get_user(unit, p))
600                                 break;
601                         err = ppp_connect_channel(pch, unit);
602                         break;
603
604                 case PPPIOCDISCONN:
605                         err = ppp_disconnect_channel(pch);
606                         break;
607
608                 default:
609                         down_read(&pch->chan_sem);
610                         chan = pch->chan;
611                         err = -ENOTTY;
612                         if (chan && chan->ops->ioctl)
613                                 err = chan->ops->ioctl(chan, cmd, arg);
614                         up_read(&pch->chan_sem);
615                 }
616                 return err;
617         }
618
619         if (pf->kind != INTERFACE) {
620                 /* can't happen */
621                 printk(KERN_ERR "PPP: not interface or channel??\n");
622                 return -EINVAL;
623         }
624
625         ppp = PF_TO_PPP(pf);
626         switch (cmd) {
627         case PPPIOCSMRU:
628                 if (get_user(val, p))
629                         break;
630                 ppp->mru = val;
631                 err = 0;
632                 break;
633
634         case PPPIOCSFLAGS:
635                 if (get_user(val, p))
636                         break;
637                 ppp_lock(ppp);
638                 cflags = ppp->flags & ~val;
639                 ppp->flags = val & SC_FLAG_BITS;
640                 ppp_unlock(ppp);
641                 if (cflags & SC_CCP_OPEN)
642                         ppp_ccp_closed(ppp);
643                 err = 0;
644                 break;
645
646         case PPPIOCGFLAGS:
647                 val = ppp->flags | ppp->xstate | ppp->rstate;
648                 if (put_user(val, p))
649                         break;
650                 err = 0;
651                 break;
652
653         case PPPIOCSCOMPRESS:
654                 err = ppp_set_compress(ppp, arg);
655                 break;
656
657         case PPPIOCGUNIT:
658                 if (put_user(ppp->file.index, p))
659                         break;
660                 err = 0;
661                 break;
662
663         case PPPIOCSDEBUG:
664                 if (get_user(val, p))
665                         break;
666                 ppp->debug = val;
667                 err = 0;
668                 break;
669
670         case PPPIOCGDEBUG:
671                 if (put_user(ppp->debug, p))
672                         break;
673                 err = 0;
674                 break;
675
676         case PPPIOCGIDLE:
677                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
678                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
679                 if (copy_to_user(argp, &idle, sizeof(idle)))
680                         break;
681                 err = 0;
682                 break;
683
684         case PPPIOCSMAXCID:
685                 if (get_user(val, p))
686                         break;
687                 val2 = 15;
688                 if ((val >> 16) != 0) {
689                         val2 = val >> 16;
690                         val &= 0xffff;
691                 }
692                 vj = slhc_init(val2+1, val+1);
693                 if (!vj) {
694                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
695                         err = -ENOMEM;
696                         break;
697                 }
698                 ppp_lock(ppp);
699                 if (ppp->vj)
700                         slhc_free(ppp->vj);
701                 ppp->vj = vj;
702                 ppp_unlock(ppp);
703                 err = 0;
704                 break;
705
706         case PPPIOCGNPMODE:
707         case PPPIOCSNPMODE:
708                 if (copy_from_user(&npi, argp, sizeof(npi)))
709                         break;
710                 err = proto_to_npindex(npi.protocol);
711                 if (err < 0)
712                         break;
713                 i = err;
714                 if (cmd == PPPIOCGNPMODE) {
715                         err = -EFAULT;
716                         npi.mode = ppp->npmode[i];
717                         if (copy_to_user(argp, &npi, sizeof(npi)))
718                                 break;
719                 } else {
720                         ppp->npmode[i] = npi.mode;
721                         /* we may be able to transmit more packets now (??) */
722                         netif_wake_queue(ppp->dev);
723                 }
724                 err = 0;
725                 break;
726
727 #ifdef CONFIG_PPP_FILTER
728         case PPPIOCSPASS:
729         {
730                 struct sock_filter *code;
731                 err = get_filter(argp, &code);
732                 if (err >= 0) {
733                         ppp_lock(ppp);
734                         kfree(ppp->pass_filter);
735                         ppp->pass_filter = code;
736                         ppp->pass_len = err;
737                         ppp_unlock(ppp);
738                         err = 0;
739                 }
740                 break;
741         }
742         case PPPIOCSACTIVE:
743         {
744                 struct sock_filter *code;
745                 err = get_filter(argp, &code);
746                 if (err >= 0) {
747                         ppp_lock(ppp);
748                         kfree(ppp->active_filter);
749                         ppp->active_filter = code;
750                         ppp->active_len = err;
751                         ppp_unlock(ppp);
752                         err = 0;
753                 }
754                 break;
755         }
756 #endif /* CONFIG_PPP_FILTER */
757
758 #ifdef CONFIG_PPP_MULTILINK
759         case PPPIOCSMRRU:
760                 if (get_user(val, p))
761                         break;
762                 ppp_recv_lock(ppp);
763                 ppp->mrru = val;
764                 ppp_recv_unlock(ppp);
765                 err = 0;
766                 break;
767 #endif /* CONFIG_PPP_MULTILINK */
768
769         default:
770                 err = -ENOTTY;
771         }
772
773         return err;
774 }
775
776 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
777                                 unsigned int cmd, unsigned long arg)
778 {
779         int unit, err = -EFAULT;
780         struct ppp *ppp;
781         struct channel *chan;
782         int __user *p = (int __user *)arg;
783
784         switch (cmd) {
785         case PPPIOCNEWUNIT:
786                 /* Create a new ppp unit */
787                 if (get_user(unit, p))
788                         break;
789                 ppp = ppp_create_interface(unit, &err);
790                 if (!ppp)
791                         break;
792                 file->private_data = &ppp->file;
793                 ppp->owner = file;
794                 err = -EFAULT;
795                 if (put_user(ppp->file.index, p))
796                         break;
797                 err = 0;
798                 break;
799
800         case PPPIOCATTACH:
801                 /* Attach to an existing ppp unit */
802                 if (get_user(unit, p))
803                         break;
804                 mutex_lock(&all_ppp_mutex);
805                 err = -ENXIO;
806                 ppp = ppp_find_unit(unit);
807                 if (ppp) {
808                         atomic_inc(&ppp->file.refcnt);
809                         file->private_data = &ppp->file;
810                         err = 0;
811                 }
812                 mutex_unlock(&all_ppp_mutex);
813                 break;
814
815         case PPPIOCATTCHAN:
816                 if (get_user(unit, p))
817                         break;
818                 spin_lock_bh(&all_channels_lock);
819                 err = -ENXIO;
820                 chan = ppp_find_channel(unit);
821                 if (chan) {
822                         atomic_inc(&chan->file.refcnt);
823                         file->private_data = &chan->file;
824                         err = 0;
825                 }
826                 spin_unlock_bh(&all_channels_lock);
827                 break;
828
829         default:
830                 err = -ENOTTY;
831         }
832         return err;
833 }
834
835 static const struct file_operations ppp_device_fops = {
836         .owner          = THIS_MODULE,
837         .read           = ppp_read,
838         .write          = ppp_write,
839         .poll           = ppp_poll,
840         .ioctl          = ppp_ioctl,
841         .open           = ppp_open,
842         .release        = ppp_release
843 };
844
845 #define PPP_MAJOR       108
846
847 /* Called at boot time if ppp is compiled into the kernel,
848    or at module load time (from init_module) if compiled as a module. */
849 static int __init ppp_init(void)
850 {
851         int err;
852
853         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
854         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
855         if (!err) {
856                 ppp_class = class_create(THIS_MODULE, "ppp");
857                 if (IS_ERR(ppp_class)) {
858                         err = PTR_ERR(ppp_class);
859                         goto out_chrdev;
860                 }
861                 device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), "ppp");
862         }
863
864 out:
865         if (err)
866                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
867         return err;
868
869 out_chrdev:
870         unregister_chrdev(PPP_MAJOR, "ppp");
871         goto out;
872 }
873
874 /*
875  * Network interface unit routines.
876  */
877 static int
878 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
879 {
880         struct ppp *ppp = (struct ppp *) dev->priv;
881         int npi, proto;
882         unsigned char *pp;
883
884         npi = ethertype_to_npindex(ntohs(skb->protocol));
885         if (npi < 0)
886                 goto outf;
887
888         /* Drop, accept or reject the packet */
889         switch (ppp->npmode[npi]) {
890         case NPMODE_PASS:
891                 break;
892         case NPMODE_QUEUE:
893                 /* it would be nice to have a way to tell the network
894                    system to queue this one up for later. */
895                 goto outf;
896         case NPMODE_DROP:
897         case NPMODE_ERROR:
898                 goto outf;
899         }
900
901         /* Put the 2-byte PPP protocol number on the front,
902            making sure there is room for the address and control fields. */
903         if (skb_cow_head(skb, PPP_HDRLEN))
904                 goto outf;
905
906         pp = skb_push(skb, 2);
907         proto = npindex_to_proto[npi];
908         pp[0] = proto >> 8;
909         pp[1] = proto;
910
911         netif_stop_queue(dev);
912         skb_queue_tail(&ppp->file.xq, skb);
913         ppp_xmit_process(ppp);
914         return 0;
915
916  outf:
917         kfree_skb(skb);
918         ++ppp->dev->stats.tx_dropped;
919         return 0;
920 }
921
922 static int
923 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
924 {
925         struct ppp *ppp = dev->priv;
926         int err = -EFAULT;
927         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
928         struct ppp_stats stats;
929         struct ppp_comp_stats cstats;
930         char *vers;
931
932         switch (cmd) {
933         case SIOCGPPPSTATS:
934                 ppp_get_stats(ppp, &stats);
935                 if (copy_to_user(addr, &stats, sizeof(stats)))
936                         break;
937                 err = 0;
938                 break;
939
940         case SIOCGPPPCSTATS:
941                 memset(&cstats, 0, sizeof(cstats));
942                 if (ppp->xc_state)
943                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
944                 if (ppp->rc_state)
945                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
946                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
947                         break;
948                 err = 0;
949                 break;
950
951         case SIOCGPPPVER:
952                 vers = PPP_VERSION;
953                 if (copy_to_user(addr, vers, strlen(vers) + 1))
954                         break;
955                 err = 0;
956                 break;
957
958         default:
959                 err = -EINVAL;
960         }
961
962         return err;
963 }
964
965 static void ppp_setup(struct net_device *dev)
966 {
967         dev->hard_header_len = PPP_HDRLEN;
968         dev->mtu = PPP_MTU;
969         dev->addr_len = 0;
970         dev->tx_queue_len = 3;
971         dev->type = ARPHRD_PPP;
972         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
973 }
974
975 /*
976  * Transmit-side routines.
977  */
978
979 /*
980  * Called to do any work queued up on the transmit side
981  * that can now be done.
982  */
983 static void
984 ppp_xmit_process(struct ppp *ppp)
985 {
986         struct sk_buff *skb;
987
988         ppp_xmit_lock(ppp);
989         if (ppp->dev) {
990                 ppp_push(ppp);
991                 while (!ppp->xmit_pending
992                        && (skb = skb_dequeue(&ppp->file.xq)))
993                         ppp_send_frame(ppp, skb);
994                 /* If there's no work left to do, tell the core net
995                    code that we can accept some more. */
996                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
997                         netif_wake_queue(ppp->dev);
998         }
999         ppp_xmit_unlock(ppp);
1000 }
1001
1002 static inline struct sk_buff *
1003 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1004 {
1005         struct sk_buff *new_skb;
1006         int len;
1007         int new_skb_size = ppp->dev->mtu +
1008                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1009         int compressor_skb_size = ppp->dev->mtu +
1010                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1011         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1012         if (!new_skb) {
1013                 if (net_ratelimit())
1014                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1015                 return NULL;
1016         }
1017         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1018                 skb_reserve(new_skb,
1019                             ppp->dev->hard_header_len - PPP_HDRLEN);
1020
1021         /* compressor still expects A/C bytes in hdr */
1022         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1023                                    new_skb->data, skb->len + 2,
1024                                    compressor_skb_size);
1025         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1026                 kfree_skb(skb);
1027                 skb = new_skb;
1028                 skb_put(skb, len);
1029                 skb_pull(skb, 2);       /* pull off A/C bytes */
1030         } else if (len == 0) {
1031                 /* didn't compress, or CCP not up yet */
1032                 kfree_skb(new_skb);
1033                 new_skb = skb;
1034         } else {
1035                 /*
1036                  * (len < 0)
1037                  * MPPE requires that we do not send unencrypted
1038                  * frames.  The compressor will return -1 if we
1039                  * should drop the frame.  We cannot simply test
1040                  * the compress_proto because MPPE and MPPC share
1041                  * the same number.
1042                  */
1043                 if (net_ratelimit())
1044                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1045                 kfree_skb(skb);
1046                 kfree_skb(new_skb);
1047                 new_skb = NULL;
1048         }
1049         return new_skb;
1050 }
1051
1052 /*
1053  * Compress and send a frame.
1054  * The caller should have locked the xmit path,
1055  * and xmit_pending should be 0.
1056  */
1057 static void
1058 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1059 {
1060         int proto = PPP_PROTO(skb);
1061         struct sk_buff *new_skb;
1062         int len;
1063         unsigned char *cp;
1064
1065         if (proto < 0x8000) {
1066 #ifdef CONFIG_PPP_FILTER
1067                 /* check if we should pass this packet */
1068                 /* the filter instructions are constructed assuming
1069                    a four-byte PPP header on each packet */
1070                 *skb_push(skb, 2) = 1;
1071                 if (ppp->pass_filter
1072                     && sk_run_filter(skb, ppp->pass_filter,
1073                                      ppp->pass_len) == 0) {
1074                         if (ppp->debug & 1)
1075                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1076                         kfree_skb(skb);
1077                         return;
1078                 }
1079                 /* if this packet passes the active filter, record the time */
1080                 if (!(ppp->active_filter
1081                       && sk_run_filter(skb, ppp->active_filter,
1082                                        ppp->active_len) == 0))
1083                         ppp->last_xmit = jiffies;
1084                 skb_pull(skb, 2);
1085 #else
1086                 /* for data packets, record the time */
1087                 ppp->last_xmit = jiffies;
1088 #endif /* CONFIG_PPP_FILTER */
1089         }
1090
1091         ++ppp->dev->stats.tx_packets;
1092         ppp->dev->stats.tx_bytes += skb->len - 2;
1093
1094         switch (proto) {
1095         case PPP_IP:
1096                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1097                         break;
1098                 /* try to do VJ TCP header compression */
1099                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1100                                     GFP_ATOMIC);
1101                 if (!new_skb) {
1102                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1103                         goto drop;
1104                 }
1105                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1106                 cp = skb->data + 2;
1107                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1108                                     new_skb->data + 2, &cp,
1109                                     !(ppp->flags & SC_NO_TCP_CCID));
1110                 if (cp == skb->data + 2) {
1111                         /* didn't compress */
1112                         kfree_skb(new_skb);
1113                 } else {
1114                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1115                                 proto = PPP_VJC_COMP;
1116                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1117                         } else {
1118                                 proto = PPP_VJC_UNCOMP;
1119                                 cp[0] = skb->data[2];
1120                         }
1121                         kfree_skb(skb);
1122                         skb = new_skb;
1123                         cp = skb_put(skb, len + 2);
1124                         cp[0] = 0;
1125                         cp[1] = proto;
1126                 }
1127                 break;
1128
1129         case PPP_CCP:
1130                 /* peek at outbound CCP frames */
1131                 ppp_ccp_peek(ppp, skb, 0);
1132                 break;
1133         }
1134
1135         /* try to do packet compression */
1136         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
1137             && proto != PPP_LCP && proto != PPP_CCP) {
1138                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1139                         if (net_ratelimit())
1140                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1141                         goto drop;
1142                 }
1143                 skb = pad_compress_skb(ppp, skb);
1144                 if (!skb)
1145                         goto drop;
1146         }
1147
1148         /*
1149          * If we are waiting for traffic (demand dialling),
1150          * queue it up for pppd to receive.
1151          */
1152         if (ppp->flags & SC_LOOP_TRAFFIC) {
1153                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1154                         goto drop;
1155                 skb_queue_tail(&ppp->file.rq, skb);
1156                 wake_up_interruptible(&ppp->file.rwait);
1157                 return;
1158         }
1159
1160         ppp->xmit_pending = skb;
1161         ppp_push(ppp);
1162         return;
1163
1164  drop:
1165         if (skb)
1166                 kfree_skb(skb);
1167         ++ppp->dev->stats.tx_errors;
1168 }
1169
1170 /*
1171  * Try to send the frame in xmit_pending.
1172  * The caller should have the xmit path locked.
1173  */
1174 static void
1175 ppp_push(struct ppp *ppp)
1176 {
1177         struct list_head *list;
1178         struct channel *pch;
1179         struct sk_buff *skb = ppp->xmit_pending;
1180
1181         if (!skb)
1182                 return;
1183
1184         list = &ppp->channels;
1185         if (list_empty(list)) {
1186                 /* nowhere to send the packet, just drop it */
1187                 ppp->xmit_pending = NULL;
1188                 kfree_skb(skb);
1189                 return;
1190         }
1191
1192         if ((ppp->flags & SC_MULTILINK) == 0) {
1193                 /* not doing multilink: send it down the first channel */
1194                 list = list->next;
1195                 pch = list_entry(list, struct channel, clist);
1196
1197                 spin_lock_bh(&pch->downl);
1198                 if (pch->chan) {
1199                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1200                                 ppp->xmit_pending = NULL;
1201                 } else {
1202                         /* channel got unregistered */
1203                         kfree_skb(skb);
1204                         ppp->xmit_pending = NULL;
1205                 }
1206                 spin_unlock_bh(&pch->downl);
1207                 return;
1208         }
1209
1210 #ifdef CONFIG_PPP_MULTILINK
1211         /* Multilink: fragment the packet over as many links
1212            as can take the packet at the moment. */
1213         if (!ppp_mp_explode(ppp, skb))
1214                 return;
1215 #endif /* CONFIG_PPP_MULTILINK */
1216
1217         ppp->xmit_pending = NULL;
1218         kfree_skb(skb);
1219 }
1220
1221 #ifdef CONFIG_PPP_MULTILINK
1222 /*
1223  * Divide a packet to be transmitted into fragments and
1224  * send them out the individual links.
1225  */
1226 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1227 {
1228         int len, fragsize;
1229         int i, bits, hdrlen, mtu;
1230         int flen;
1231         int navail, nfree;
1232         int nbigger;
1233         unsigned char *p, *q;
1234         struct list_head *list;
1235         struct channel *pch;
1236         struct sk_buff *frag;
1237         struct ppp_channel *chan;
1238
1239         nfree = 0;      /* # channels which have no packet already queued */
1240         navail = 0;     /* total # of usable channels (not deregistered) */
1241         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1242         i = 0;
1243         list_for_each_entry(pch, &ppp->channels, clist) {
1244                 navail += pch->avail = (pch->chan != NULL);
1245                 if (pch->avail) {
1246                         if (skb_queue_empty(&pch->file.xq) ||
1247                             !pch->had_frag) {
1248                                 pch->avail = 2;
1249                                 ++nfree;
1250                         }
1251                         if (!pch->had_frag && i < ppp->nxchan)
1252                                 ppp->nxchan = i;
1253                 }
1254                 ++i;
1255         }
1256
1257         /*
1258          * Don't start sending this packet unless at least half of
1259          * the channels are free.  This gives much better TCP
1260          * performance if we have a lot of channels.
1261          */
1262         if (nfree == 0 || nfree < navail / 2)
1263                 return 0;       /* can't take now, leave it in xmit_pending */
1264
1265         /* Do protocol field compression (XXX this should be optional) */
1266         p = skb->data;
1267         len = skb->len;
1268         if (*p == 0) {
1269                 ++p;
1270                 --len;
1271         }
1272
1273         /*
1274          * Decide on fragment size.
1275          * We create a fragment for each free channel regardless of
1276          * how small they are (i.e. even 0 length) in order to minimize
1277          * the time that it will take to detect when a channel drops
1278          * a fragment.
1279          */
1280         fragsize = len;
1281         if (nfree > 1)
1282                 fragsize = DIV_ROUND_UP(fragsize, nfree);
1283         /* nbigger channels get fragsize bytes, the rest get fragsize-1,
1284            except if nbigger==0, then they all get fragsize. */
1285         nbigger = len % nfree;
1286
1287         /* skip to the channel after the one we last used
1288            and start at that one */
1289         list = &ppp->channels;
1290         for (i = 0; i < ppp->nxchan; ++i) {
1291                 list = list->next;
1292                 if (list == &ppp->channels) {
1293                         i = 0;
1294                         break;
1295                 }
1296         }
1297
1298         /* create a fragment for each channel */
1299         bits = B;
1300         while (nfree > 0 || len > 0) {
1301                 list = list->next;
1302                 if (list == &ppp->channels) {
1303                         i = 0;
1304                         continue;
1305                 }
1306                 pch = list_entry(list, struct channel, clist);
1307                 ++i;
1308                 if (!pch->avail)
1309                         continue;
1310
1311                 /*
1312                  * Skip this channel if it has a fragment pending already and
1313                  * we haven't given a fragment to all of the free channels.
1314                  */
1315                 if (pch->avail == 1) {
1316                         if (nfree > 0)
1317                                 continue;
1318                 } else {
1319                         --nfree;
1320                         pch->avail = 1;
1321                 }
1322
1323                 /* check the channel's mtu and whether it is still attached. */
1324                 spin_lock_bh(&pch->downl);
1325                 if (pch->chan == NULL) {
1326                         /* can't use this channel, it's being deregistered */
1327                         spin_unlock_bh(&pch->downl);
1328                         pch->avail = 0;
1329                         if (--navail == 0)
1330                                 break;
1331                         continue;
1332                 }
1333
1334                 /*
1335                  * Create a fragment for this channel of
1336                  * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
1337                  * If mtu+2-hdrlen < 4, that is a ridiculously small
1338                  * MTU, so we use mtu = 2 + hdrlen.
1339                  */
1340                 if (fragsize > len)
1341                         fragsize = len;
1342                 flen = fragsize;
1343                 mtu = pch->chan->mtu + 2 - hdrlen;
1344                 if (mtu < 4)
1345                         mtu = 4;
1346                 if (flen > mtu)
1347                         flen = mtu;
1348                 if (flen == len && nfree == 0)
1349                         bits |= E;
1350                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1351                 if (!frag)
1352                         goto noskb;
1353                 q = skb_put(frag, flen + hdrlen);
1354
1355                 /* make the MP header */
1356                 q[0] = PPP_MP >> 8;
1357                 q[1] = PPP_MP;
1358                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1359                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1360                         q[3] = ppp->nxseq;
1361                 } else {
1362                         q[2] = bits;
1363                         q[3] = ppp->nxseq >> 16;
1364                         q[4] = ppp->nxseq >> 8;
1365                         q[5] = ppp->nxseq;
1366                 }
1367
1368                 /*
1369                  * Copy the data in.
1370                  * Unfortunately there is a bug in older versions of
1371                  * the Linux PPP multilink reconstruction code where it
1372                  * drops 0-length fragments.  Therefore we make sure the
1373                  * fragment has at least one byte of data.  Any bytes
1374                  * we add in this situation will end up as padding on the
1375                  * end of the reconstructed packet.
1376                  */
1377                 if (flen == 0)
1378                         *skb_put(frag, 1) = 0;
1379                 else
1380                         memcpy(q + hdrlen, p, flen);
1381
1382                 /* try to send it down the channel */
1383                 chan = pch->chan;
1384                 if (!skb_queue_empty(&pch->file.xq) ||
1385                     !chan->ops->start_xmit(chan, frag))
1386                         skb_queue_tail(&pch->file.xq, frag);
1387                 pch->had_frag = 1;
1388                 p += flen;
1389                 len -= flen;
1390                 ++ppp->nxseq;
1391                 bits = 0;
1392                 spin_unlock_bh(&pch->downl);
1393
1394                 if (--nbigger == 0 && fragsize > 0)
1395                         --fragsize;
1396         }
1397         ppp->nxchan = i;
1398
1399         return 1;
1400
1401  noskb:
1402         spin_unlock_bh(&pch->downl);
1403         if (ppp->debug & 1)
1404                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1405         ++ppp->dev->stats.tx_errors;
1406         ++ppp->nxseq;
1407         return 1;       /* abandon the frame */
1408 }
1409 #endif /* CONFIG_PPP_MULTILINK */
1410
1411 /*
1412  * Try to send data out on a channel.
1413  */
1414 static void
1415 ppp_channel_push(struct channel *pch)
1416 {
1417         struct sk_buff *skb;
1418         struct ppp *ppp;
1419
1420         spin_lock_bh(&pch->downl);
1421         if (pch->chan) {
1422                 while (!skb_queue_empty(&pch->file.xq)) {
1423                         skb = skb_dequeue(&pch->file.xq);
1424                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1425                                 /* put the packet back and try again later */
1426                                 skb_queue_head(&pch->file.xq, skb);
1427                                 break;
1428                         }
1429                 }
1430         } else {
1431                 /* channel got deregistered */
1432                 skb_queue_purge(&pch->file.xq);
1433         }
1434         spin_unlock_bh(&pch->downl);
1435         /* see if there is anything from the attached unit to be sent */
1436         if (skb_queue_empty(&pch->file.xq)) {
1437                 read_lock_bh(&pch->upl);
1438                 ppp = pch->ppp;
1439                 if (ppp)
1440                         ppp_xmit_process(ppp);
1441                 read_unlock_bh(&pch->upl);
1442         }
1443 }
1444
1445 /*
1446  * Receive-side routines.
1447  */
1448
1449 /* misuse a few fields of the skb for MP reconstruction */
1450 #define sequence        priority
1451 #define BEbits          cb[0]
1452
1453 static inline void
1454 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1455 {
1456         ppp_recv_lock(ppp);
1457         /* ppp->dev == 0 means interface is closing down */
1458         if (ppp->dev)
1459                 ppp_receive_frame(ppp, skb, pch);
1460         else
1461                 kfree_skb(skb);
1462         ppp_recv_unlock(ppp);
1463 }
1464
1465 void
1466 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1467 {
1468         struct channel *pch = chan->ppp;
1469         int proto;
1470
1471         if (!pch || skb->len == 0) {
1472                 kfree_skb(skb);
1473                 return;
1474         }
1475
1476         proto = PPP_PROTO(skb);
1477         read_lock_bh(&pch->upl);
1478         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1479                 /* put it on the channel queue */
1480                 skb_queue_tail(&pch->file.rq, skb);
1481                 /* drop old frames if queue too long */
1482                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1483                        && (skb = skb_dequeue(&pch->file.rq)))
1484                         kfree_skb(skb);
1485                 wake_up_interruptible(&pch->file.rwait);
1486         } else {
1487                 ppp_do_recv(pch->ppp, skb, pch);
1488         }
1489         read_unlock_bh(&pch->upl);
1490 }
1491
1492 /* Put a 0-length skb in the receive queue as an error indication */
1493 void
1494 ppp_input_error(struct ppp_channel *chan, int code)
1495 {
1496         struct channel *pch = chan->ppp;
1497         struct sk_buff *skb;
1498
1499         if (!pch)
1500                 return;
1501
1502         read_lock_bh(&pch->upl);
1503         if (pch->ppp) {
1504                 skb = alloc_skb(0, GFP_ATOMIC);
1505                 if (skb) {
1506                         skb->len = 0;           /* probably unnecessary */
1507                         skb->cb[0] = code;
1508                         ppp_do_recv(pch->ppp, skb, pch);
1509                 }
1510         }
1511         read_unlock_bh(&pch->upl);
1512 }
1513
1514 /*
1515  * We come in here to process a received frame.
1516  * The receive side of the ppp unit is locked.
1517  */
1518 static void
1519 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1520 {
1521         if (pskb_may_pull(skb, 2)) {
1522 #ifdef CONFIG_PPP_MULTILINK
1523                 /* XXX do channel-level decompression here */
1524                 if (PPP_PROTO(skb) == PPP_MP)
1525                         ppp_receive_mp_frame(ppp, skb, pch);
1526                 else
1527 #endif /* CONFIG_PPP_MULTILINK */
1528                         ppp_receive_nonmp_frame(ppp, skb);
1529                 return;
1530         }
1531
1532         if (skb->len > 0)
1533                 /* note: a 0-length skb is used as an error indication */
1534                 ++ppp->dev->stats.rx_length_errors;
1535
1536         kfree_skb(skb);
1537         ppp_receive_error(ppp);
1538 }
1539
1540 static void
1541 ppp_receive_error(struct ppp *ppp)
1542 {
1543         ++ppp->dev->stats.rx_errors;
1544         if (ppp->vj)
1545                 slhc_toss(ppp->vj);
1546 }
1547
1548 static void
1549 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1550 {
1551         struct sk_buff *ns;
1552         int proto, len, npi;
1553
1554         /*
1555          * Decompress the frame, if compressed.
1556          * Note that some decompressors need to see uncompressed frames
1557          * that come in as well as compressed frames.
1558          */
1559         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
1560             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1561                 skb = ppp_decompress_frame(ppp, skb);
1562
1563         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1564                 goto err;
1565
1566         proto = PPP_PROTO(skb);
1567         switch (proto) {
1568         case PPP_VJC_COMP:
1569                 /* decompress VJ compressed packets */
1570                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1571                         goto err;
1572
1573                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1574                         /* copy to a new sk_buff with more tailroom */
1575                         ns = dev_alloc_skb(skb->len + 128);
1576                         if (!ns) {
1577                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1578                                 goto err;
1579                         }
1580                         skb_reserve(ns, 2);
1581                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1582                         kfree_skb(skb);
1583                         skb = ns;
1584                 }
1585                 else
1586                         skb->ip_summed = CHECKSUM_NONE;
1587
1588                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1589                 if (len <= 0) {
1590                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1591                         goto err;
1592                 }
1593                 len += 2;
1594                 if (len > skb->len)
1595                         skb_put(skb, len - skb->len);
1596                 else if (len < skb->len)
1597                         skb_trim(skb, len);
1598                 proto = PPP_IP;
1599                 break;
1600
1601         case PPP_VJC_UNCOMP:
1602                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1603                         goto err;
1604
1605                 /* Until we fix the decompressor need to make sure
1606                  * data portion is linear.
1607                  */
1608                 if (!pskb_may_pull(skb, skb->len))
1609                         goto err;
1610
1611                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1612                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1613                         goto err;
1614                 }
1615                 proto = PPP_IP;
1616                 break;
1617
1618         case PPP_CCP:
1619                 ppp_ccp_peek(ppp, skb, 1);
1620                 break;
1621         }
1622
1623         ++ppp->dev->stats.rx_packets;
1624         ppp->dev->stats.rx_bytes += skb->len - 2;
1625
1626         npi = proto_to_npindex(proto);
1627         if (npi < 0) {
1628                 /* control or unknown frame - pass it to pppd */
1629                 skb_queue_tail(&ppp->file.rq, skb);
1630                 /* limit queue length by dropping old frames */
1631                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1632                        && (skb = skb_dequeue(&ppp->file.rq)))
1633                         kfree_skb(skb);
1634                 /* wake up any process polling or blocking on read */
1635                 wake_up_interruptible(&ppp->file.rwait);
1636
1637         } else {
1638                 /* network protocol frame - give it to the kernel */
1639
1640 #ifdef CONFIG_PPP_FILTER
1641                 /* check if the packet passes the pass and active filters */
1642                 /* the filter instructions are constructed assuming
1643                    a four-byte PPP header on each packet */
1644                 if (ppp->pass_filter || ppp->active_filter) {
1645                         if (skb_cloned(skb) &&
1646                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1647                                 goto err;
1648
1649                         *skb_push(skb, 2) = 0;
1650                         if (ppp->pass_filter
1651                             && sk_run_filter(skb, ppp->pass_filter,
1652                                              ppp->pass_len) == 0) {
1653                                 if (ppp->debug & 1)
1654                                         printk(KERN_DEBUG "PPP: inbound frame "
1655                                                "not passed\n");
1656                                 kfree_skb(skb);
1657                                 return;
1658                         }
1659                         if (!(ppp->active_filter
1660                               && sk_run_filter(skb, ppp->active_filter,
1661                                                ppp->active_len) == 0))
1662                                 ppp->last_recv = jiffies;
1663                         __skb_pull(skb, 2);
1664                 } else
1665 #endif /* CONFIG_PPP_FILTER */
1666                         ppp->last_recv = jiffies;
1667
1668                 if ((ppp->dev->flags & IFF_UP) == 0
1669                     || ppp->npmode[npi] != NPMODE_PASS) {
1670                         kfree_skb(skb);
1671                 } else {
1672                         /* chop off protocol */
1673                         skb_pull_rcsum(skb, 2);
1674                         skb->dev = ppp->dev;
1675                         skb->protocol = htons(npindex_to_ethertype[npi]);
1676                         skb_reset_mac_header(skb);
1677                         netif_rx(skb);
1678                         ppp->dev->last_rx = jiffies;
1679                 }
1680         }
1681         return;
1682
1683  err:
1684         kfree_skb(skb);
1685         ppp_receive_error(ppp);
1686 }
1687
1688 static struct sk_buff *
1689 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1690 {
1691         int proto = PPP_PROTO(skb);
1692         struct sk_buff *ns;
1693         int len;
1694
1695         /* Until we fix all the decompressor's need to make sure
1696          * data portion is linear.
1697          */
1698         if (!pskb_may_pull(skb, skb->len))
1699                 goto err;
1700
1701         if (proto == PPP_COMP) {
1702                 int obuff_size;
1703
1704                 switch(ppp->rcomp->compress_proto) {
1705                 case CI_MPPE:
1706                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1707                         break;
1708                 default:
1709                         obuff_size = ppp->mru + PPP_HDRLEN;
1710                         break;
1711                 }
1712
1713                 ns = dev_alloc_skb(obuff_size);
1714                 if (!ns) {
1715                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1716                         goto err;
1717                 }
1718                 /* the decompressor still expects the A/C bytes in the hdr */
1719                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1720                                 skb->len + 2, ns->data, obuff_size);
1721                 if (len < 0) {
1722                         /* Pass the compressed frame to pppd as an
1723                            error indication. */
1724                         if (len == DECOMP_FATALERROR)
1725                                 ppp->rstate |= SC_DC_FERROR;
1726                         kfree_skb(ns);
1727                         goto err;
1728                 }
1729
1730                 kfree_skb(skb);
1731                 skb = ns;
1732                 skb_put(skb, len);
1733                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1734
1735         } else {
1736                 /* Uncompressed frame - pass to decompressor so it
1737                    can update its dictionary if necessary. */
1738                 if (ppp->rcomp->incomp)
1739                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1740                                            skb->len + 2);
1741         }
1742
1743         return skb;
1744
1745  err:
1746         ppp->rstate |= SC_DC_ERROR;
1747         ppp_receive_error(ppp);
1748         return skb;
1749 }
1750
1751 #ifdef CONFIG_PPP_MULTILINK
1752 /*
1753  * Receive a multilink frame.
1754  * We put it on the reconstruction queue and then pull off
1755  * as many completed frames as we can.
1756  */
1757 static void
1758 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1759 {
1760         u32 mask, seq;
1761         struct channel *ch;
1762         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1763
1764         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1765                 goto err;               /* no good, throw it away */
1766
1767         /* Decode sequence number and begin/end bits */
1768         if (ppp->flags & SC_MP_SHORTSEQ) {
1769                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1770                 mask = 0xfff;
1771         } else {
1772                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1773                 mask = 0xffffff;
1774         }
1775         skb->BEbits = skb->data[2];
1776         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1777
1778         /*
1779          * Do protocol ID decompression on the first fragment of each packet.
1780          */
1781         if ((skb->BEbits & B) && (skb->data[0] & 1))
1782                 *skb_push(skb, 1) = 0;
1783
1784         /*
1785          * Expand sequence number to 32 bits, making it as close
1786          * as possible to ppp->minseq.
1787          */
1788         seq |= ppp->minseq & ~mask;
1789         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1790                 seq += mask + 1;
1791         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1792                 seq -= mask + 1;        /* should never happen */
1793         skb->sequence = seq;
1794         pch->lastseq = seq;
1795
1796         /*
1797          * If this packet comes before the next one we were expecting,
1798          * drop it.
1799          */
1800         if (seq_before(seq, ppp->nextseq)) {
1801                 kfree_skb(skb);
1802                 ++ppp->dev->stats.rx_dropped;
1803                 ppp_receive_error(ppp);
1804                 return;
1805         }
1806
1807         /*
1808          * Reevaluate minseq, the minimum over all channels of the
1809          * last sequence number received on each channel.  Because of
1810          * the increasing sequence number rule, we know that any fragment
1811          * before `minseq' which hasn't arrived is never going to arrive.
1812          * The list of channels can't change because we have the receive
1813          * side of the ppp unit locked.
1814          */
1815         list_for_each_entry(ch, &ppp->channels, clist) {
1816                 if (seq_before(ch->lastseq, seq))
1817                         seq = ch->lastseq;
1818         }
1819         if (seq_before(ppp->minseq, seq))
1820                 ppp->minseq = seq;
1821
1822         /* Put the fragment on the reconstruction queue */
1823         ppp_mp_insert(ppp, skb);
1824
1825         /* If the queue is getting long, don't wait any longer for packets
1826            before the start of the queue. */
1827         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN
1828             && seq_before(ppp->minseq, ppp->mrq.next->sequence))
1829                 ppp->minseq = ppp->mrq.next->sequence;
1830
1831         /* Pull completed packets off the queue and receive them. */
1832         while ((skb = ppp_mp_reconstruct(ppp)))
1833                 ppp_receive_nonmp_frame(ppp, skb);
1834
1835         return;
1836
1837  err:
1838         kfree_skb(skb);
1839         ppp_receive_error(ppp);
1840 }
1841
1842 /*
1843  * Insert a fragment on the MP reconstruction queue.
1844  * The queue is ordered by increasing sequence number.
1845  */
1846 static void
1847 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1848 {
1849         struct sk_buff *p;
1850         struct sk_buff_head *list = &ppp->mrq;
1851         u32 seq = skb->sequence;
1852
1853         /* N.B. we don't need to lock the list lock because we have the
1854            ppp unit receive-side lock. */
1855         for (p = list->next; p != (struct sk_buff *)list; p = p->next)
1856                 if (seq_before(seq, p->sequence))
1857                         break;
1858         __skb_insert(skb, p->prev, p, list);
1859 }
1860
1861 /*
1862  * Reconstruct a packet from the MP fragment queue.
1863  * We go through increasing sequence numbers until we find a
1864  * complete packet, or we get to the sequence number for a fragment
1865  * which hasn't arrived but might still do so.
1866  */
1867 static struct sk_buff *
1868 ppp_mp_reconstruct(struct ppp *ppp)
1869 {
1870         u32 seq = ppp->nextseq;
1871         u32 minseq = ppp->minseq;
1872         struct sk_buff_head *list = &ppp->mrq;
1873         struct sk_buff *p, *next;
1874         struct sk_buff *head, *tail;
1875         struct sk_buff *skb = NULL;
1876         int lost = 0, len = 0;
1877
1878         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1879                 return NULL;
1880         head = list->next;
1881         tail = NULL;
1882         for (p = head; p != (struct sk_buff *) list; p = next) {
1883                 next = p->next;
1884                 if (seq_before(p->sequence, seq)) {
1885                         /* this can't happen, anyway ignore the skb */
1886                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1887                                p->sequence, seq);
1888                         head = next;
1889                         continue;
1890                 }
1891                 if (p->sequence != seq) {
1892                         /* Fragment `seq' is missing.  If it is after
1893                            minseq, it might arrive later, so stop here. */
1894                         if (seq_after(seq, minseq))
1895                                 break;
1896                         /* Fragment `seq' is lost, keep going. */
1897                         lost = 1;
1898                         seq = seq_before(minseq, p->sequence)?
1899                                 minseq + 1: p->sequence;
1900                         next = p;
1901                         continue;
1902                 }
1903
1904                 /*
1905                  * At this point we know that all the fragments from
1906                  * ppp->nextseq to seq are either present or lost.
1907                  * Also, there are no complete packets in the queue
1908                  * that have no missing fragments and end before this
1909                  * fragment.
1910                  */
1911
1912                 /* B bit set indicates this fragment starts a packet */
1913                 if (p->BEbits & B) {
1914                         head = p;
1915                         lost = 0;
1916                         len = 0;
1917                 }
1918
1919                 len += p->len;
1920
1921                 /* Got a complete packet yet? */
1922                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1923                         if (len > ppp->mrru + 2) {
1924                                 ++ppp->dev->stats.rx_length_errors;
1925                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1926                                        " is too long (%d)\n", len);
1927                         } else if (p == head) {
1928                                 /* fragment is complete packet - reuse skb */
1929                                 tail = p;
1930                                 skb = skb_get(p);
1931                                 break;
1932                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1933                                 ++ppp->dev->stats.rx_missed_errors;
1934                                 printk(KERN_DEBUG "PPP: no memory for "
1935                                        "reconstructed packet");
1936                         } else {
1937                                 tail = p;
1938                                 break;
1939                         }
1940                         ppp->nextseq = seq + 1;
1941                 }
1942
1943                 /*
1944                  * If this is the ending fragment of a packet,
1945                  * and we haven't found a complete valid packet yet,
1946                  * we can discard up to and including this fragment.
1947                  */
1948                 if (p->BEbits & E)
1949                         head = next;
1950
1951                 ++seq;
1952         }
1953
1954         /* If we have a complete packet, copy it all into one skb. */
1955         if (tail != NULL) {
1956                 /* If we have discarded any fragments,
1957                    signal a receive error. */
1958                 if (head->sequence != ppp->nextseq) {
1959                         if (ppp->debug & 1)
1960                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1961                                        ppp->nextseq, head->sequence-1);
1962                         ++ppp->dev->stats.rx_dropped;
1963                         ppp_receive_error(ppp);
1964                 }
1965
1966                 if (head != tail)
1967                         /* copy to a single skb */
1968                         for (p = head; p != tail->next; p = p->next)
1969                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1970                 ppp->nextseq = tail->sequence + 1;
1971                 head = tail->next;
1972         }
1973
1974         /* Discard all the skbuffs that we have copied the data out of
1975            or that we can't use. */
1976         while ((p = list->next) != head) {
1977                 __skb_unlink(p, list);
1978                 kfree_skb(p);
1979         }
1980
1981         return skb;
1982 }
1983 #endif /* CONFIG_PPP_MULTILINK */
1984
1985 /*
1986  * Channel interface.
1987  */
1988
1989 /*
1990  * Create a new, unattached ppp channel.
1991  */
1992 int
1993 ppp_register_channel(struct ppp_channel *chan)
1994 {
1995         struct channel *pch;
1996
1997         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
1998         if (!pch)
1999                 return -ENOMEM;
2000         pch->ppp = NULL;
2001         pch->chan = chan;
2002         chan->ppp = pch;
2003         init_ppp_file(&pch->file, CHANNEL);
2004         pch->file.hdrlen = chan->hdrlen;
2005 #ifdef CONFIG_PPP_MULTILINK
2006         pch->lastseq = -1;
2007 #endif /* CONFIG_PPP_MULTILINK */
2008         init_rwsem(&pch->chan_sem);
2009         spin_lock_init(&pch->downl);
2010         rwlock_init(&pch->upl);
2011         spin_lock_bh(&all_channels_lock);
2012         pch->file.index = ++last_channel_index;
2013         list_add(&pch->list, &new_channels);
2014         atomic_inc(&channel_count);
2015         spin_unlock_bh(&all_channels_lock);
2016         return 0;
2017 }
2018
2019 /*
2020  * Return the index of a channel.
2021  */
2022 int ppp_channel_index(struct ppp_channel *chan)
2023 {
2024         struct channel *pch = chan->ppp;
2025
2026         if (pch)
2027                 return pch->file.index;
2028         return -1;
2029 }
2030
2031 /*
2032  * Return the PPP unit number to which a channel is connected.
2033  */
2034 int ppp_unit_number(struct ppp_channel *chan)
2035 {
2036         struct channel *pch = chan->ppp;
2037         int unit = -1;
2038
2039         if (pch) {
2040                 read_lock_bh(&pch->upl);
2041                 if (pch->ppp)
2042                         unit = pch->ppp->file.index;
2043                 read_unlock_bh(&pch->upl);
2044         }
2045         return unit;
2046 }
2047
2048 /*
2049  * Disconnect a channel from the generic layer.
2050  * This must be called in process context.
2051  */
2052 void
2053 ppp_unregister_channel(struct ppp_channel *chan)
2054 {
2055         struct channel *pch = chan->ppp;
2056
2057         if (!pch)
2058                 return;         /* should never happen */
2059         chan->ppp = NULL;
2060
2061         /*
2062          * This ensures that we have returned from any calls into the
2063          * the channel's start_xmit or ioctl routine before we proceed.
2064          */
2065         down_write(&pch->chan_sem);
2066         spin_lock_bh(&pch->downl);
2067         pch->chan = NULL;
2068         spin_unlock_bh(&pch->downl);
2069         up_write(&pch->chan_sem);
2070         ppp_disconnect_channel(pch);
2071         spin_lock_bh(&all_channels_lock);
2072         list_del(&pch->list);
2073         spin_unlock_bh(&all_channels_lock);
2074         pch->file.dead = 1;
2075         wake_up_interruptible(&pch->file.rwait);
2076         if (atomic_dec_and_test(&pch->file.refcnt))
2077                 ppp_destroy_channel(pch);
2078 }
2079
2080 /*
2081  * Callback from a channel when it can accept more to transmit.
2082  * This should be called at BH/softirq level, not interrupt level.
2083  */
2084 void
2085 ppp_output_wakeup(struct ppp_channel *chan)
2086 {
2087         struct channel *pch = chan->ppp;
2088
2089         if (!pch)
2090                 return;
2091         ppp_channel_push(pch);
2092 }
2093
2094 /*
2095  * Compression control.
2096  */
2097
2098 /* Process the PPPIOCSCOMPRESS ioctl. */
2099 static int
2100 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2101 {
2102         int err;
2103         struct compressor *cp, *ocomp;
2104         struct ppp_option_data data;
2105         void *state, *ostate;
2106         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2107
2108         err = -EFAULT;
2109         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2110             || (data.length <= CCP_MAX_OPTION_LENGTH
2111                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2112                 goto out;
2113         err = -EINVAL;
2114         if (data.length > CCP_MAX_OPTION_LENGTH
2115             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2116                 goto out;
2117
2118         cp = find_compressor(ccp_option[0]);
2119 #ifdef CONFIG_KMOD
2120         if (!cp) {
2121                 request_module("ppp-compress-%d", ccp_option[0]);
2122                 cp = find_compressor(ccp_option[0]);
2123         }
2124 #endif /* CONFIG_KMOD */
2125         if (!cp)
2126                 goto out;
2127
2128         err = -ENOBUFS;
2129         if (data.transmit) {
2130                 state = cp->comp_alloc(ccp_option, data.length);
2131                 if (state) {
2132                         ppp_xmit_lock(ppp);
2133                         ppp->xstate &= ~SC_COMP_RUN;
2134                         ocomp = ppp->xcomp;
2135                         ostate = ppp->xc_state;
2136                         ppp->xcomp = cp;
2137                         ppp->xc_state = state;
2138                         ppp_xmit_unlock(ppp);
2139                         if (ostate) {
2140                                 ocomp->comp_free(ostate);
2141                                 module_put(ocomp->owner);
2142                         }
2143                         err = 0;
2144                 } else
2145                         module_put(cp->owner);
2146
2147         } else {
2148                 state = cp->decomp_alloc(ccp_option, data.length);
2149                 if (state) {
2150                         ppp_recv_lock(ppp);
2151                         ppp->rstate &= ~SC_DECOMP_RUN;
2152                         ocomp = ppp->rcomp;
2153                         ostate = ppp->rc_state;
2154                         ppp->rcomp = cp;
2155                         ppp->rc_state = state;
2156                         ppp_recv_unlock(ppp);
2157                         if (ostate) {
2158                                 ocomp->decomp_free(ostate);
2159                                 module_put(ocomp->owner);
2160                         }
2161                         err = 0;
2162                 } else
2163                         module_put(cp->owner);
2164         }
2165
2166  out:
2167         return err;
2168 }
2169
2170 /*
2171  * Look at a CCP packet and update our state accordingly.
2172  * We assume the caller has the xmit or recv path locked.
2173  */
2174 static void
2175 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2176 {
2177         unsigned char *dp;
2178         int len;
2179
2180         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2181                 return; /* no header */
2182         dp = skb->data + 2;
2183
2184         switch (CCP_CODE(dp)) {
2185         case CCP_CONFREQ:
2186
2187                 /* A ConfReq starts negotiation of compression
2188                  * in one direction of transmission,
2189                  * and hence brings it down...but which way?
2190                  *
2191                  * Remember:
2192                  * A ConfReq indicates what the sender would like to receive
2193                  */
2194                 if(inbound)
2195                         /* He is proposing what I should send */
2196                         ppp->xstate &= ~SC_COMP_RUN;
2197                 else
2198                         /* I am proposing to what he should send */
2199                         ppp->rstate &= ~SC_DECOMP_RUN;
2200
2201                 break;
2202
2203         case CCP_TERMREQ:
2204         case CCP_TERMACK:
2205                 /*
2206                  * CCP is going down, both directions of transmission
2207                  */
2208                 ppp->rstate &= ~SC_DECOMP_RUN;
2209                 ppp->xstate &= ~SC_COMP_RUN;
2210                 break;
2211
2212         case CCP_CONFACK:
2213                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2214                         break;
2215                 len = CCP_LENGTH(dp);
2216                 if (!pskb_may_pull(skb, len + 2))
2217                         return;         /* too short */
2218                 dp += CCP_HDRLEN;
2219                 len -= CCP_HDRLEN;
2220                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2221                         break;
2222                 if (inbound) {
2223                         /* we will start receiving compressed packets */
2224                         if (!ppp->rc_state)
2225                                 break;
2226                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2227                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2228                                 ppp->rstate |= SC_DECOMP_RUN;
2229                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2230                         }
2231                 } else {
2232                         /* we will soon start sending compressed packets */
2233                         if (!ppp->xc_state)
2234                                 break;
2235                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2236                                         ppp->file.index, 0, ppp->debug))
2237                                 ppp->xstate |= SC_COMP_RUN;
2238                 }
2239                 break;
2240
2241         case CCP_RESETACK:
2242                 /* reset the [de]compressor */
2243                 if ((ppp->flags & SC_CCP_UP) == 0)
2244                         break;
2245                 if (inbound) {
2246                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2247                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2248                                 ppp->rstate &= ~SC_DC_ERROR;
2249                         }
2250                 } else {
2251                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2252                                 ppp->xcomp->comp_reset(ppp->xc_state);
2253                 }
2254                 break;
2255         }
2256 }
2257
2258 /* Free up compression resources. */
2259 static void
2260 ppp_ccp_closed(struct ppp *ppp)
2261 {
2262         void *xstate, *rstate;
2263         struct compressor *xcomp, *rcomp;
2264
2265         ppp_lock(ppp);
2266         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2267         ppp->xstate = 0;
2268         xcomp = ppp->xcomp;
2269         xstate = ppp->xc_state;
2270         ppp->xc_state = NULL;
2271         ppp->rstate = 0;
2272         rcomp = ppp->rcomp;
2273         rstate = ppp->rc_state;
2274         ppp->rc_state = NULL;
2275         ppp_unlock(ppp);
2276
2277         if (xstate) {
2278                 xcomp->comp_free(xstate);
2279                 module_put(xcomp->owner);
2280         }
2281         if (rstate) {
2282                 rcomp->decomp_free(rstate);
2283                 module_put(rcomp->owner);
2284         }
2285 }
2286
2287 /* List of compressors. */
2288 static LIST_HEAD(compressor_list);
2289 static DEFINE_SPINLOCK(compressor_list_lock);
2290
2291 struct compressor_entry {
2292         struct list_head list;
2293         struct compressor *comp;
2294 };
2295
2296 static struct compressor_entry *
2297 find_comp_entry(int proto)
2298 {
2299         struct compressor_entry *ce;
2300
2301         list_for_each_entry(ce, &compressor_list, list) {
2302                 if (ce->comp->compress_proto == proto)
2303                         return ce;
2304         }
2305         return NULL;
2306 }
2307
2308 /* Register a compressor */
2309 int
2310 ppp_register_compressor(struct compressor *cp)
2311 {
2312         struct compressor_entry *ce;
2313         int ret;
2314         spin_lock(&compressor_list_lock);
2315         ret = -EEXIST;
2316         if (find_comp_entry(cp->compress_proto))
2317                 goto out;
2318         ret = -ENOMEM;
2319         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2320         if (!ce)
2321                 goto out;
2322         ret = 0;
2323         ce->comp = cp;
2324         list_add(&ce->list, &compressor_list);
2325  out:
2326         spin_unlock(&compressor_list_lock);
2327         return ret;
2328 }
2329
2330 /* Unregister a compressor */
2331 void
2332 ppp_unregister_compressor(struct compressor *cp)
2333 {
2334         struct compressor_entry *ce;
2335
2336         spin_lock(&compressor_list_lock);
2337         ce = find_comp_entry(cp->compress_proto);
2338         if (ce && ce->comp == cp) {
2339                 list_del(&ce->list);
2340                 kfree(ce);
2341         }
2342         spin_unlock(&compressor_list_lock);
2343 }
2344
2345 /* Find a compressor. */
2346 static struct compressor *
2347 find_compressor(int type)
2348 {
2349         struct compressor_entry *ce;
2350         struct compressor *cp = NULL;
2351
2352         spin_lock(&compressor_list_lock);
2353         ce = find_comp_entry(type);
2354         if (ce) {
2355                 cp = ce->comp;
2356                 if (!try_module_get(cp->owner))
2357                         cp = NULL;
2358         }
2359         spin_unlock(&compressor_list_lock);
2360         return cp;
2361 }
2362
2363 /*
2364  * Miscelleneous stuff.
2365  */
2366
2367 static void
2368 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2369 {
2370         struct slcompress *vj = ppp->vj;
2371
2372         memset(st, 0, sizeof(*st));
2373         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2374         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2375         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2376         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2377         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2378         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2379         if (!vj)
2380                 return;
2381         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2382         st->vj.vjs_compressed = vj->sls_o_compressed;
2383         st->vj.vjs_searches = vj->sls_o_searches;
2384         st->vj.vjs_misses = vj->sls_o_misses;
2385         st->vj.vjs_errorin = vj->sls_i_error;
2386         st->vj.vjs_tossed = vj->sls_i_tossed;
2387         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2388         st->vj.vjs_compressedin = vj->sls_i_compressed;
2389 }
2390
2391 /*
2392  * Stuff for handling the lists of ppp units and channels
2393  * and for initialization.
2394  */
2395
2396 /*
2397  * Create a new ppp interface unit.  Fails if it can't allocate memory
2398  * or if there is already a unit with the requested number.
2399  * unit == -1 means allocate a new number.
2400  */
2401 static struct ppp *
2402 ppp_create_interface(int unit, int *retp)
2403 {
2404         struct ppp *ppp;
2405         struct net_device *dev = NULL;
2406         int ret = -ENOMEM;
2407         int i;
2408
2409         ppp = kzalloc(sizeof(struct ppp), GFP_KERNEL);
2410         if (!ppp)
2411                 goto out;
2412         dev = alloc_netdev(0, "", ppp_setup);
2413         if (!dev)
2414                 goto out1;
2415
2416         ppp->mru = PPP_MRU;
2417         init_ppp_file(&ppp->file, INTERFACE);
2418         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2419         for (i = 0; i < NUM_NP; ++i)
2420                 ppp->npmode[i] = NPMODE_PASS;
2421         INIT_LIST_HEAD(&ppp->channels);
2422         spin_lock_init(&ppp->rlock);
2423         spin_lock_init(&ppp->wlock);
2424 #ifdef CONFIG_PPP_MULTILINK
2425         ppp->minseq = -1;
2426         skb_queue_head_init(&ppp->mrq);
2427 #endif /* CONFIG_PPP_MULTILINK */
2428         ppp->dev = dev;
2429         dev->priv = ppp;
2430
2431         dev->hard_start_xmit = ppp_start_xmit;
2432         dev->do_ioctl = ppp_net_ioctl;
2433
2434         ret = -EEXIST;
2435         mutex_lock(&all_ppp_mutex);
2436         if (unit < 0)
2437                 unit = cardmap_find_first_free(all_ppp_units);
2438         else if (cardmap_get(all_ppp_units, unit) != NULL)
2439                 goto out2;      /* unit already exists */
2440
2441         /* Initialize the new ppp unit */
2442         ppp->file.index = unit;
2443         sprintf(dev->name, "ppp%d", unit);
2444
2445         ret = register_netdev(dev);
2446         if (ret != 0) {
2447                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2448                        dev->name, ret);
2449                 goto out2;
2450         }
2451
2452         atomic_inc(&ppp_unit_count);
2453         ret = cardmap_set(&all_ppp_units, unit, ppp);
2454         if (ret != 0)
2455                 goto out3;
2456
2457         mutex_unlock(&all_ppp_mutex);
2458         *retp = 0;
2459         return ppp;
2460
2461 out3:
2462         atomic_dec(&ppp_unit_count);
2463         unregister_netdev(dev);
2464 out2:
2465         mutex_unlock(&all_ppp_mutex);
2466         free_netdev(dev);
2467 out1:
2468         kfree(ppp);
2469 out:
2470         *retp = ret;
2471         return NULL;
2472 }
2473
2474 /*
2475  * Initialize a ppp_file structure.
2476  */
2477 static void
2478 init_ppp_file(struct ppp_file *pf, int kind)
2479 {
2480         pf->kind = kind;
2481         skb_queue_head_init(&pf->xq);
2482         skb_queue_head_init(&pf->rq);
2483         atomic_set(&pf->refcnt, 1);
2484         init_waitqueue_head(&pf->rwait);
2485 }
2486
2487 /*
2488  * Take down a ppp interface unit - called when the owning file
2489  * (the one that created the unit) is closed or detached.
2490  */
2491 static void ppp_shutdown_interface(struct ppp *ppp)
2492 {
2493         struct net_device *dev;
2494
2495         mutex_lock(&all_ppp_mutex);
2496         ppp_lock(ppp);
2497         dev = ppp->dev;
2498         ppp->dev = NULL;
2499         ppp_unlock(ppp);
2500         /* This will call dev_close() for us. */
2501         if (dev) {
2502                 unregister_netdev(dev);
2503                 free_netdev(dev);
2504         }
2505         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2506         ppp->file.dead = 1;
2507         ppp->owner = NULL;
2508         wake_up_interruptible(&ppp->file.rwait);
2509         mutex_unlock(&all_ppp_mutex);
2510 }
2511
2512 /*
2513  * Free the memory used by a ppp unit.  This is only called once
2514  * there are no channels connected to the unit and no file structs
2515  * that reference the unit.
2516  */
2517 static void ppp_destroy_interface(struct ppp *ppp)
2518 {
2519         atomic_dec(&ppp_unit_count);
2520
2521         if (!ppp->file.dead || ppp->n_channels) {
2522                 /* "can't happen" */
2523                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2524                        "n_channels=%d !\n", ppp, ppp->file.dead,
2525                        ppp->n_channels);
2526                 return;
2527         }
2528
2529         ppp_ccp_closed(ppp);
2530         if (ppp->vj) {
2531                 slhc_free(ppp->vj);
2532                 ppp->vj = NULL;
2533         }
2534         skb_queue_purge(&ppp->file.xq);
2535         skb_queue_purge(&ppp->file.rq);
2536 #ifdef CONFIG_PPP_MULTILINK
2537         skb_queue_purge(&ppp->mrq);
2538 #endif /* CONFIG_PPP_MULTILINK */
2539 #ifdef CONFIG_PPP_FILTER
2540         kfree(ppp->pass_filter);
2541         ppp->pass_filter = NULL;
2542         kfree(ppp->active_filter);
2543         ppp->active_filter = NULL;
2544 #endif /* CONFIG_PPP_FILTER */
2545
2546         if (ppp->xmit_pending)
2547                 kfree_skb(ppp->xmit_pending);
2548
2549         kfree(ppp);
2550 }
2551
2552 /*
2553  * Locate an existing ppp unit.
2554  * The caller should have locked the all_ppp_mutex.
2555  */
2556 static struct ppp *
2557 ppp_find_unit(int unit)
2558 {
2559         return cardmap_get(all_ppp_units, unit);
2560 }
2561
2562 /*
2563  * Locate an existing ppp channel.
2564  * The caller should have locked the all_channels_lock.
2565  * First we look in the new_channels list, then in the
2566  * all_channels list.  If found in the new_channels list,
2567  * we move it to the all_channels list.  This is for speed
2568  * when we have a lot of channels in use.
2569  */
2570 static struct channel *
2571 ppp_find_channel(int unit)
2572 {
2573         struct channel *pch;
2574
2575         list_for_each_entry(pch, &new_channels, list) {
2576                 if (pch->file.index == unit) {
2577                         list_move(&pch->list, &all_channels);
2578                         return pch;
2579                 }
2580         }
2581         list_for_each_entry(pch, &all_channels, list) {
2582                 if (pch->file.index == unit)
2583                         return pch;
2584         }
2585         return NULL;
2586 }
2587
2588 /*
2589  * Connect a PPP channel to a PPP interface unit.
2590  */
2591 static int
2592 ppp_connect_channel(struct channel *pch, int unit)
2593 {
2594         struct ppp *ppp;
2595         int ret = -ENXIO;
2596         int hdrlen;
2597
2598         mutex_lock(&all_ppp_mutex);
2599         ppp = ppp_find_unit(unit);
2600         if (!ppp)
2601                 goto out;
2602         write_lock_bh(&pch->upl);
2603         ret = -EINVAL;
2604         if (pch->ppp)
2605                 goto outl;
2606
2607         ppp_lock(ppp);
2608         if (pch->file.hdrlen > ppp->file.hdrlen)
2609                 ppp->file.hdrlen = pch->file.hdrlen;
2610         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2611         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2612                 ppp->dev->hard_header_len = hdrlen;
2613         list_add_tail(&pch->clist, &ppp->channels);
2614         ++ppp->n_channels;
2615         pch->ppp = ppp;
2616         atomic_inc(&ppp->file.refcnt);
2617         ppp_unlock(ppp);
2618         ret = 0;
2619
2620  outl:
2621         write_unlock_bh(&pch->upl);
2622  out:
2623         mutex_unlock(&all_ppp_mutex);
2624         return ret;
2625 }
2626
2627 /*
2628  * Disconnect a channel from its ppp unit.
2629  */
2630 static int
2631 ppp_disconnect_channel(struct channel *pch)
2632 {
2633         struct ppp *ppp;
2634         int err = -EINVAL;
2635
2636         write_lock_bh(&pch->upl);
2637         ppp = pch->ppp;
2638         pch->ppp = NULL;
2639         write_unlock_bh(&pch->upl);
2640         if (ppp) {
2641                 /* remove it from the ppp unit's list */
2642                 ppp_lock(ppp);
2643                 list_del(&pch->clist);
2644                 if (--ppp->n_channels == 0)
2645                         wake_up_interruptible(&ppp->file.rwait);
2646                 ppp_unlock(ppp);
2647                 if (atomic_dec_and_test(&ppp->file.refcnt))
2648                         ppp_destroy_interface(ppp);
2649                 err = 0;
2650         }
2651         return err;
2652 }
2653
2654 /*
2655  * Free up the resources used by a ppp channel.
2656  */
2657 static void ppp_destroy_channel(struct channel *pch)
2658 {
2659         atomic_dec(&channel_count);
2660
2661         if (!pch->file.dead) {
2662                 /* "can't happen" */
2663                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2664                        pch);
2665                 return;
2666         }
2667         skb_queue_purge(&pch->file.xq);
2668         skb_queue_purge(&pch->file.rq);
2669         kfree(pch);
2670 }
2671
2672 static void __exit ppp_cleanup(void)
2673 {
2674         /* should never happen */
2675         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2676                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2677         cardmap_destroy(&all_ppp_units);
2678         unregister_chrdev(PPP_MAJOR, "ppp");
2679         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2680         class_destroy(ppp_class);
2681 }
2682
2683 /*
2684  * Cardmap implementation.
2685  */
2686 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2687 {
2688         struct cardmap *p;
2689         int i;
2690
2691         for (p = map; p != NULL; ) {
2692                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2693                         return NULL;
2694                 if (p->shift == 0)
2695                         return p->ptr[i];
2696                 nr &= ~(CARDMAP_MASK << p->shift);
2697                 p = p->ptr[i];
2698         }
2699         return NULL;
2700 }
2701
2702 static int cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2703 {
2704         struct cardmap *p;
2705         int i;
2706
2707         p = *pmap;
2708         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2709                 do {
2710                         /* need a new top level */
2711                         struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL);
2712                         if (!np)
2713                                 goto enomem;
2714                         np->ptr[0] = p;
2715                         if (p != NULL) {
2716                                 np->shift = p->shift + CARDMAP_ORDER;
2717                                 p->parent = np;
2718                         } else
2719                                 np->shift = 0;
2720                         p = np;
2721                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2722                 *pmap = p;
2723         }
2724         while (p->shift > 0) {
2725                 i = (nr >> p->shift) & CARDMAP_MASK;
2726                 if (p->ptr[i] == NULL) {
2727                         struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL);
2728                         if (!np)
2729                                 goto enomem;
2730                         np->shift = p->shift - CARDMAP_ORDER;
2731                         np->parent = p;
2732                         p->ptr[i] = np;
2733                 }
2734                 if (ptr == NULL)
2735                         clear_bit(i, &p->inuse);
2736                 p = p->ptr[i];
2737         }
2738         i = nr & CARDMAP_MASK;
2739         p->ptr[i] = ptr;
2740         if (ptr != NULL)
2741                 set_bit(i, &p->inuse);
2742         else
2743                 clear_bit(i, &p->inuse);
2744         return 0;
2745  enomem:
2746         return -ENOMEM;
2747 }
2748
2749 static unsigned int cardmap_find_first_free(struct cardmap *map)
2750 {
2751         struct cardmap *p;
2752         unsigned int nr = 0;
2753         int i;
2754
2755         if ((p = map) == NULL)
2756                 return 0;
2757         for (;;) {
2758                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2759                 if (i >= CARDMAP_WIDTH) {
2760                         if (p->parent == NULL)
2761                                 return CARDMAP_WIDTH << p->shift;
2762                         p = p->parent;
2763                         i = (nr >> p->shift) & CARDMAP_MASK;
2764                         set_bit(i, &p->inuse);
2765                         continue;
2766                 }
2767                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2768                 if (p->shift == 0 || p->ptr[i] == NULL)
2769                         return nr;
2770                 p = p->ptr[i];
2771         }
2772 }
2773
2774 static void cardmap_destroy(struct cardmap **pmap)
2775 {
2776         struct cardmap *p, *np;
2777         int i;
2778
2779         for (p = *pmap; p != NULL; p = np) {
2780                 if (p->shift != 0) {
2781                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2782                                 if (p->ptr[i] != NULL)
2783                                         break;
2784                         if (i < CARDMAP_WIDTH) {
2785                                 np = p->ptr[i];
2786                                 p->ptr[i] = NULL;
2787                                 continue;
2788                         }
2789                 }
2790                 np = p->parent;
2791                 kfree(p);
2792         }
2793         *pmap = NULL;
2794 }
2795
2796 /* Module/initialization stuff */
2797
2798 module_init(ppp_init);
2799 module_exit(ppp_cleanup);
2800
2801 EXPORT_SYMBOL(ppp_register_channel);
2802 EXPORT_SYMBOL(ppp_unregister_channel);
2803 EXPORT_SYMBOL(ppp_channel_index);
2804 EXPORT_SYMBOL(ppp_unit_number);
2805 EXPORT_SYMBOL(ppp_input);
2806 EXPORT_SYMBOL(ppp_input_error);
2807 EXPORT_SYMBOL(ppp_output_wakeup);
2808 EXPORT_SYMBOL(ppp_register_compressor);
2809 EXPORT_SYMBOL(ppp_unregister_compressor);
2810 MODULE_LICENSE("GPL");
2811 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2812 MODULE_ALIAS("/dev/ppp");