ppp: convert to net_device_ops
[linux-2.6.git] / drivers / net / ppp_generic.c
1 /*
2  * Generic PPP layer for Linux.
3  *
4  * Copyright 1999-2002 Paul Mackerras.
5  *
6  *  This program is free software; you can redistribute it and/or
7  *  modify it under the terms of the GNU General Public License
8  *  as published by the Free Software Foundation; either version
9  *  2 of the License, or (at your option) any later version.
10  *
11  * The generic PPP layer handles the PPP network interfaces, the
12  * /dev/ppp device, packet and VJ compression, and multilink.
13  * It talks to PPP `channels' via the interface defined in
14  * include/linux/ppp_channel.h.  Channels provide the basic means for
15  * sending and receiving PPP frames on some kind of communications
16  * channel.
17  *
18  * Part of the code in this driver was inspired by the old async-only
19  * PPP driver, written by Michael Callahan and Al Longyear, and
20  * subsequently hacked by Paul Mackerras.
21  *
22  * ==FILEVERSION 20041108==
23  */
24
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/kmod.h>
28 #include <linux/init.h>
29 #include <linux/list.h>
30 #include <linux/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 *unused, 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 long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
551 {
552         struct ppp_file *pf = file->private_data;
553         struct ppp *ppp;
554         int err = -EFAULT, val, val2, i;
555         struct ppp_idle idle;
556         struct npioctl npi;
557         int unit, cflags;
558         struct slcompress *vj;
559         void __user *argp = (void __user *)arg;
560         int __user *p = argp;
561
562         if (!pf)
563                 return ppp_unattached_ioctl(pf, file, cmd, arg);
564
565         if (cmd == PPPIOCDETACH) {
566                 /*
567                  * We have to be careful here... if the file descriptor
568                  * has been dup'd, we could have another process in the
569                  * middle of a poll using the same file *, so we had
570                  * better not free the interface data structures -
571                  * instead we fail the ioctl.  Even in this case, we
572                  * shut down the interface if we are the owner of it.
573                  * Actually, we should get rid of PPPIOCDETACH, userland
574                  * (i.e. pppd) could achieve the same effect by closing
575                  * this fd and reopening /dev/ppp.
576                  */
577                 err = -EINVAL;
578                 lock_kernel();
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_long_read(&file->f_count) <= 2) {
585                         ppp_release(NULL, file);
586                         err = 0;
587                 } else
588                         printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
589                                atomic_long_read(&file->f_count));
590                 unlock_kernel();
591                 return err;
592         }
593
594         if (pf->kind == CHANNEL) {
595                 struct channel *pch;
596                 struct ppp_channel *chan;
597
598                 lock_kernel();
599                 pch = PF_TO_CHANNEL(pf);
600
601                 switch (cmd) {
602                 case PPPIOCCONNECT:
603                         if (get_user(unit, p))
604                                 break;
605                         err = ppp_connect_channel(pch, unit);
606                         break;
607
608                 case PPPIOCDISCONN:
609                         err = ppp_disconnect_channel(pch);
610                         break;
611
612                 default:
613                         down_read(&pch->chan_sem);
614                         chan = pch->chan;
615                         err = -ENOTTY;
616                         if (chan && chan->ops->ioctl)
617                                 err = chan->ops->ioctl(chan, cmd, arg);
618                         up_read(&pch->chan_sem);
619                 }
620                 unlock_kernel();
621                 return err;
622         }
623
624         if (pf->kind != INTERFACE) {
625                 /* can't happen */
626                 printk(KERN_ERR "PPP: not interface or channel??\n");
627                 return -EINVAL;
628         }
629
630         lock_kernel();
631         ppp = PF_TO_PPP(pf);
632         switch (cmd) {
633         case PPPIOCSMRU:
634                 if (get_user(val, p))
635                         break;
636                 ppp->mru = val;
637                 err = 0;
638                 break;
639
640         case PPPIOCSFLAGS:
641                 if (get_user(val, p))
642                         break;
643                 ppp_lock(ppp);
644                 cflags = ppp->flags & ~val;
645                 ppp->flags = val & SC_FLAG_BITS;
646                 ppp_unlock(ppp);
647                 if (cflags & SC_CCP_OPEN)
648                         ppp_ccp_closed(ppp);
649                 err = 0;
650                 break;
651
652         case PPPIOCGFLAGS:
653                 val = ppp->flags | ppp->xstate | ppp->rstate;
654                 if (put_user(val, p))
655                         break;
656                 err = 0;
657                 break;
658
659         case PPPIOCSCOMPRESS:
660                 err = ppp_set_compress(ppp, arg);
661                 break;
662
663         case PPPIOCGUNIT:
664                 if (put_user(ppp->file.index, p))
665                         break;
666                 err = 0;
667                 break;
668
669         case PPPIOCSDEBUG:
670                 if (get_user(val, p))
671                         break;
672                 ppp->debug = val;
673                 err = 0;
674                 break;
675
676         case PPPIOCGDEBUG:
677                 if (put_user(ppp->debug, p))
678                         break;
679                 err = 0;
680                 break;
681
682         case PPPIOCGIDLE:
683                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
684                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
685                 if (copy_to_user(argp, &idle, sizeof(idle)))
686                         break;
687                 err = 0;
688                 break;
689
690         case PPPIOCSMAXCID:
691                 if (get_user(val, p))
692                         break;
693                 val2 = 15;
694                 if ((val >> 16) != 0) {
695                         val2 = val >> 16;
696                         val &= 0xffff;
697                 }
698                 vj = slhc_init(val2+1, val+1);
699                 if (!vj) {
700                         printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
701                         err = -ENOMEM;
702                         break;
703                 }
704                 ppp_lock(ppp);
705                 if (ppp->vj)
706                         slhc_free(ppp->vj);
707                 ppp->vj = vj;
708                 ppp_unlock(ppp);
709                 err = 0;
710                 break;
711
712         case PPPIOCGNPMODE:
713         case PPPIOCSNPMODE:
714                 if (copy_from_user(&npi, argp, sizeof(npi)))
715                         break;
716                 err = proto_to_npindex(npi.protocol);
717                 if (err < 0)
718                         break;
719                 i = err;
720                 if (cmd == PPPIOCGNPMODE) {
721                         err = -EFAULT;
722                         npi.mode = ppp->npmode[i];
723                         if (copy_to_user(argp, &npi, sizeof(npi)))
724                                 break;
725                 } else {
726                         ppp->npmode[i] = npi.mode;
727                         /* we may be able to transmit more packets now (??) */
728                         netif_wake_queue(ppp->dev);
729                 }
730                 err = 0;
731                 break;
732
733 #ifdef CONFIG_PPP_FILTER
734         case PPPIOCSPASS:
735         {
736                 struct sock_filter *code;
737                 err = get_filter(argp, &code);
738                 if (err >= 0) {
739                         ppp_lock(ppp);
740                         kfree(ppp->pass_filter);
741                         ppp->pass_filter = code;
742                         ppp->pass_len = err;
743                         ppp_unlock(ppp);
744                         err = 0;
745                 }
746                 break;
747         }
748         case PPPIOCSACTIVE:
749         {
750                 struct sock_filter *code;
751                 err = get_filter(argp, &code);
752                 if (err >= 0) {
753                         ppp_lock(ppp);
754                         kfree(ppp->active_filter);
755                         ppp->active_filter = code;
756                         ppp->active_len = err;
757                         ppp_unlock(ppp);
758                         err = 0;
759                 }
760                 break;
761         }
762 #endif /* CONFIG_PPP_FILTER */
763
764 #ifdef CONFIG_PPP_MULTILINK
765         case PPPIOCSMRRU:
766                 if (get_user(val, p))
767                         break;
768                 ppp_recv_lock(ppp);
769                 ppp->mrru = val;
770                 ppp_recv_unlock(ppp);
771                 err = 0;
772                 break;
773 #endif /* CONFIG_PPP_MULTILINK */
774
775         default:
776                 err = -ENOTTY;
777         }
778         unlock_kernel();
779         return err;
780 }
781
782 static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file,
783                                 unsigned int cmd, unsigned long arg)
784 {
785         int unit, err = -EFAULT;
786         struct ppp *ppp;
787         struct channel *chan;
788         int __user *p = (int __user *)arg;
789
790         lock_kernel();
791         switch (cmd) {
792         case PPPIOCNEWUNIT:
793                 /* Create a new ppp unit */
794                 if (get_user(unit, p))
795                         break;
796                 ppp = ppp_create_interface(unit, &err);
797                 if (!ppp)
798                         break;
799                 file->private_data = &ppp->file;
800                 ppp->owner = file;
801                 err = -EFAULT;
802                 if (put_user(ppp->file.index, p))
803                         break;
804                 err = 0;
805                 break;
806
807         case PPPIOCATTACH:
808                 /* Attach to an existing ppp unit */
809                 if (get_user(unit, p))
810                         break;
811                 mutex_lock(&all_ppp_mutex);
812                 err = -ENXIO;
813                 ppp = ppp_find_unit(unit);
814                 if (ppp) {
815                         atomic_inc(&ppp->file.refcnt);
816                         file->private_data = &ppp->file;
817                         err = 0;
818                 }
819                 mutex_unlock(&all_ppp_mutex);
820                 break;
821
822         case PPPIOCATTCHAN:
823                 if (get_user(unit, p))
824                         break;
825                 spin_lock_bh(&all_channels_lock);
826                 err = -ENXIO;
827                 chan = ppp_find_channel(unit);
828                 if (chan) {
829                         atomic_inc(&chan->file.refcnt);
830                         file->private_data = &chan->file;
831                         err = 0;
832                 }
833                 spin_unlock_bh(&all_channels_lock);
834                 break;
835
836         default:
837                 err = -ENOTTY;
838         }
839         unlock_kernel();
840         return err;
841 }
842
843 static const struct file_operations ppp_device_fops = {
844         .owner          = THIS_MODULE,
845         .read           = ppp_read,
846         .write          = ppp_write,
847         .poll           = ppp_poll,
848         .unlocked_ioctl = ppp_ioctl,
849         .open           = ppp_open,
850         .release        = ppp_release
851 };
852
853 #define PPP_MAJOR       108
854
855 /* Called at boot time if ppp is compiled into the kernel,
856    or at module load time (from init_module) if compiled as a module. */
857 static int __init ppp_init(void)
858 {
859         int err;
860
861         printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
862         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
863         if (!err) {
864                 ppp_class = class_create(THIS_MODULE, "ppp");
865                 if (IS_ERR(ppp_class)) {
866                         err = PTR_ERR(ppp_class);
867                         goto out_chrdev;
868                 }
869                 device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL,
870                               "ppp");
871         }
872
873 out:
874         if (err)
875                 printk(KERN_ERR "failed to register PPP device (%d)\n", err);
876         return err;
877
878 out_chrdev:
879         unregister_chrdev(PPP_MAJOR, "ppp");
880         goto out;
881 }
882
883 /*
884  * Network interface unit routines.
885  */
886 static int
887 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
888 {
889         struct ppp *ppp = (struct ppp *) dev->priv;
890         int npi, proto;
891         unsigned char *pp;
892
893         npi = ethertype_to_npindex(ntohs(skb->protocol));
894         if (npi < 0)
895                 goto outf;
896
897         /* Drop, accept or reject the packet */
898         switch (ppp->npmode[npi]) {
899         case NPMODE_PASS:
900                 break;
901         case NPMODE_QUEUE:
902                 /* it would be nice to have a way to tell the network
903                    system to queue this one up for later. */
904                 goto outf;
905         case NPMODE_DROP:
906         case NPMODE_ERROR:
907                 goto outf;
908         }
909
910         /* Put the 2-byte PPP protocol number on the front,
911            making sure there is room for the address and control fields. */
912         if (skb_cow_head(skb, PPP_HDRLEN))
913                 goto outf;
914
915         pp = skb_push(skb, 2);
916         proto = npindex_to_proto[npi];
917         pp[0] = proto >> 8;
918         pp[1] = proto;
919
920         netif_stop_queue(dev);
921         skb_queue_tail(&ppp->file.xq, skb);
922         ppp_xmit_process(ppp);
923         return 0;
924
925  outf:
926         kfree_skb(skb);
927         ++ppp->dev->stats.tx_dropped;
928         return 0;
929 }
930
931 static int
932 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
933 {
934         struct ppp *ppp = dev->priv;
935         int err = -EFAULT;
936         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
937         struct ppp_stats stats;
938         struct ppp_comp_stats cstats;
939         char *vers;
940
941         switch (cmd) {
942         case SIOCGPPPSTATS:
943                 ppp_get_stats(ppp, &stats);
944                 if (copy_to_user(addr, &stats, sizeof(stats)))
945                         break;
946                 err = 0;
947                 break;
948
949         case SIOCGPPPCSTATS:
950                 memset(&cstats, 0, sizeof(cstats));
951                 if (ppp->xc_state)
952                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
953                 if (ppp->rc_state)
954                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
955                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
956                         break;
957                 err = 0;
958                 break;
959
960         case SIOCGPPPVER:
961                 vers = PPP_VERSION;
962                 if (copy_to_user(addr, vers, strlen(vers) + 1))
963                         break;
964                 err = 0;
965                 break;
966
967         default:
968                 err = -EINVAL;
969         }
970
971         return err;
972 }
973
974 static const struct net_device_ops ppp_netdev_ops = {
975         .ndo_do_ioctl = ppp_net_ioctl,
976 };
977
978 static void ppp_setup(struct net_device *dev)
979 {
980         dev->netdev_ops = &ppp_netdev_ops;
981         dev->hard_header_len = PPP_HDRLEN;
982         dev->mtu = PPP_MTU;
983         dev->addr_len = 0;
984         dev->tx_queue_len = 3;
985         dev->type = ARPHRD_PPP;
986         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
987 }
988
989 /*
990  * Transmit-side routines.
991  */
992
993 /*
994  * Called to do any work queued up on the transmit side
995  * that can now be done.
996  */
997 static void
998 ppp_xmit_process(struct ppp *ppp)
999 {
1000         struct sk_buff *skb;
1001
1002         ppp_xmit_lock(ppp);
1003         if (ppp->dev) {
1004                 ppp_push(ppp);
1005                 while (!ppp->xmit_pending
1006                        && (skb = skb_dequeue(&ppp->file.xq)))
1007                         ppp_send_frame(ppp, skb);
1008                 /* If there's no work left to do, tell the core net
1009                    code that we can accept some more. */
1010                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1011                         netif_wake_queue(ppp->dev);
1012         }
1013         ppp_xmit_unlock(ppp);
1014 }
1015
1016 static inline struct sk_buff *
1017 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1018 {
1019         struct sk_buff *new_skb;
1020         int len;
1021         int new_skb_size = ppp->dev->mtu +
1022                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1023         int compressor_skb_size = ppp->dev->mtu +
1024                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1025         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1026         if (!new_skb) {
1027                 if (net_ratelimit())
1028                         printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1029                 return NULL;
1030         }
1031         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1032                 skb_reserve(new_skb,
1033                             ppp->dev->hard_header_len - PPP_HDRLEN);
1034
1035         /* compressor still expects A/C bytes in hdr */
1036         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1037                                    new_skb->data, skb->len + 2,
1038                                    compressor_skb_size);
1039         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1040                 kfree_skb(skb);
1041                 skb = new_skb;
1042                 skb_put(skb, len);
1043                 skb_pull(skb, 2);       /* pull off A/C bytes */
1044         } else if (len == 0) {
1045                 /* didn't compress, or CCP not up yet */
1046                 kfree_skb(new_skb);
1047                 new_skb = skb;
1048         } else {
1049                 /*
1050                  * (len < 0)
1051                  * MPPE requires that we do not send unencrypted
1052                  * frames.  The compressor will return -1 if we
1053                  * should drop the frame.  We cannot simply test
1054                  * the compress_proto because MPPE and MPPC share
1055                  * the same number.
1056                  */
1057                 if (net_ratelimit())
1058                         printk(KERN_ERR "ppp: compressor dropped pkt\n");
1059                 kfree_skb(skb);
1060                 kfree_skb(new_skb);
1061                 new_skb = NULL;
1062         }
1063         return new_skb;
1064 }
1065
1066 /*
1067  * Compress and send a frame.
1068  * The caller should have locked the xmit path,
1069  * and xmit_pending should be 0.
1070  */
1071 static void
1072 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1073 {
1074         int proto = PPP_PROTO(skb);
1075         struct sk_buff *new_skb;
1076         int len;
1077         unsigned char *cp;
1078
1079         if (proto < 0x8000) {
1080 #ifdef CONFIG_PPP_FILTER
1081                 /* check if we should pass this packet */
1082                 /* the filter instructions are constructed assuming
1083                    a four-byte PPP header on each packet */
1084                 *skb_push(skb, 2) = 1;
1085                 if (ppp->pass_filter
1086                     && sk_run_filter(skb, ppp->pass_filter,
1087                                      ppp->pass_len) == 0) {
1088                         if (ppp->debug & 1)
1089                                 printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1090                         kfree_skb(skb);
1091                         return;
1092                 }
1093                 /* if this packet passes the active filter, record the time */
1094                 if (!(ppp->active_filter
1095                       && sk_run_filter(skb, ppp->active_filter,
1096                                        ppp->active_len) == 0))
1097                         ppp->last_xmit = jiffies;
1098                 skb_pull(skb, 2);
1099 #else
1100                 /* for data packets, record the time */
1101                 ppp->last_xmit = jiffies;
1102 #endif /* CONFIG_PPP_FILTER */
1103         }
1104
1105         ++ppp->dev->stats.tx_packets;
1106         ppp->dev->stats.tx_bytes += skb->len - 2;
1107
1108         switch (proto) {
1109         case PPP_IP:
1110                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1111                         break;
1112                 /* try to do VJ TCP header compression */
1113                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1114                                     GFP_ATOMIC);
1115                 if (!new_skb) {
1116                         printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1117                         goto drop;
1118                 }
1119                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1120                 cp = skb->data + 2;
1121                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1122                                     new_skb->data + 2, &cp,
1123                                     !(ppp->flags & SC_NO_TCP_CCID));
1124                 if (cp == skb->data + 2) {
1125                         /* didn't compress */
1126                         kfree_skb(new_skb);
1127                 } else {
1128                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1129                                 proto = PPP_VJC_COMP;
1130                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1131                         } else {
1132                                 proto = PPP_VJC_UNCOMP;
1133                                 cp[0] = skb->data[2];
1134                         }
1135                         kfree_skb(skb);
1136                         skb = new_skb;
1137                         cp = skb_put(skb, len + 2);
1138                         cp[0] = 0;
1139                         cp[1] = proto;
1140                 }
1141                 break;
1142
1143         case PPP_CCP:
1144                 /* peek at outbound CCP frames */
1145                 ppp_ccp_peek(ppp, skb, 0);
1146                 break;
1147         }
1148
1149         /* try to do packet compression */
1150         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
1151             && proto != PPP_LCP && proto != PPP_CCP) {
1152                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1153                         if (net_ratelimit())
1154                                 printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1155                         goto drop;
1156                 }
1157                 skb = pad_compress_skb(ppp, skb);
1158                 if (!skb)
1159                         goto drop;
1160         }
1161
1162         /*
1163          * If we are waiting for traffic (demand dialling),
1164          * queue it up for pppd to receive.
1165          */
1166         if (ppp->flags & SC_LOOP_TRAFFIC) {
1167                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1168                         goto drop;
1169                 skb_queue_tail(&ppp->file.rq, skb);
1170                 wake_up_interruptible(&ppp->file.rwait);
1171                 return;
1172         }
1173
1174         ppp->xmit_pending = skb;
1175         ppp_push(ppp);
1176         return;
1177
1178  drop:
1179         if (skb)
1180                 kfree_skb(skb);
1181         ++ppp->dev->stats.tx_errors;
1182 }
1183
1184 /*
1185  * Try to send the frame in xmit_pending.
1186  * The caller should have the xmit path locked.
1187  */
1188 static void
1189 ppp_push(struct ppp *ppp)
1190 {
1191         struct list_head *list;
1192         struct channel *pch;
1193         struct sk_buff *skb = ppp->xmit_pending;
1194
1195         if (!skb)
1196                 return;
1197
1198         list = &ppp->channels;
1199         if (list_empty(list)) {
1200                 /* nowhere to send the packet, just drop it */
1201                 ppp->xmit_pending = NULL;
1202                 kfree_skb(skb);
1203                 return;
1204         }
1205
1206         if ((ppp->flags & SC_MULTILINK) == 0) {
1207                 /* not doing multilink: send it down the first channel */
1208                 list = list->next;
1209                 pch = list_entry(list, struct channel, clist);
1210
1211                 spin_lock_bh(&pch->downl);
1212                 if (pch->chan) {
1213                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1214                                 ppp->xmit_pending = NULL;
1215                 } else {
1216                         /* channel got unregistered */
1217                         kfree_skb(skb);
1218                         ppp->xmit_pending = NULL;
1219                 }
1220                 spin_unlock_bh(&pch->downl);
1221                 return;
1222         }
1223
1224 #ifdef CONFIG_PPP_MULTILINK
1225         /* Multilink: fragment the packet over as many links
1226            as can take the packet at the moment. */
1227         if (!ppp_mp_explode(ppp, skb))
1228                 return;
1229 #endif /* CONFIG_PPP_MULTILINK */
1230
1231         ppp->xmit_pending = NULL;
1232         kfree_skb(skb);
1233 }
1234
1235 #ifdef CONFIG_PPP_MULTILINK
1236 /*
1237  * Divide a packet to be transmitted into fragments and
1238  * send them out the individual links.
1239  */
1240 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1241 {
1242         int len, fragsize;
1243         int i, bits, hdrlen, mtu;
1244         int flen;
1245         int navail, nfree;
1246         int nbigger;
1247         unsigned char *p, *q;
1248         struct list_head *list;
1249         struct channel *pch;
1250         struct sk_buff *frag;
1251         struct ppp_channel *chan;
1252
1253         nfree = 0;      /* # channels which have no packet already queued */
1254         navail = 0;     /* total # of usable channels (not deregistered) */
1255         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1256         i = 0;
1257         list_for_each_entry(pch, &ppp->channels, clist) {
1258                 navail += pch->avail = (pch->chan != NULL);
1259                 if (pch->avail) {
1260                         if (skb_queue_empty(&pch->file.xq) ||
1261                             !pch->had_frag) {
1262                                 pch->avail = 2;
1263                                 ++nfree;
1264                         }
1265                         if (!pch->had_frag && i < ppp->nxchan)
1266                                 ppp->nxchan = i;
1267                 }
1268                 ++i;
1269         }
1270
1271         /*
1272          * Don't start sending this packet unless at least half of
1273          * the channels are free.  This gives much better TCP
1274          * performance if we have a lot of channels.
1275          */
1276         if (nfree == 0 || nfree < navail / 2)
1277                 return 0;       /* can't take now, leave it in xmit_pending */
1278
1279         /* Do protocol field compression (XXX this should be optional) */
1280         p = skb->data;
1281         len = skb->len;
1282         if (*p == 0) {
1283                 ++p;
1284                 --len;
1285         }
1286
1287         /*
1288          * Decide on fragment size.
1289          * We create a fragment for each free channel regardless of
1290          * how small they are (i.e. even 0 length) in order to minimize
1291          * the time that it will take to detect when a channel drops
1292          * a fragment.
1293          */
1294         fragsize = len;
1295         if (nfree > 1)
1296                 fragsize = DIV_ROUND_UP(fragsize, nfree);
1297         /* nbigger channels get fragsize bytes, the rest get fragsize-1,
1298            except if nbigger==0, then they all get fragsize. */
1299         nbigger = len % nfree;
1300
1301         /* skip to the channel after the one we last used
1302            and start at that one */
1303         list = &ppp->channels;
1304         for (i = 0; i < ppp->nxchan; ++i) {
1305                 list = list->next;
1306                 if (list == &ppp->channels) {
1307                         i = 0;
1308                         break;
1309                 }
1310         }
1311
1312         /* create a fragment for each channel */
1313         bits = B;
1314         while (nfree > 0 || len > 0) {
1315                 list = list->next;
1316                 if (list == &ppp->channels) {
1317                         i = 0;
1318                         continue;
1319                 }
1320                 pch = list_entry(list, struct channel, clist);
1321                 ++i;
1322                 if (!pch->avail)
1323                         continue;
1324
1325                 /*
1326                  * Skip this channel if it has a fragment pending already and
1327                  * we haven't given a fragment to all of the free channels.
1328                  */
1329                 if (pch->avail == 1) {
1330                         if (nfree > 0)
1331                                 continue;
1332                 } else {
1333                         --nfree;
1334                         pch->avail = 1;
1335                 }
1336
1337                 /* check the channel's mtu and whether it is still attached. */
1338                 spin_lock_bh(&pch->downl);
1339                 if (pch->chan == NULL) {
1340                         /* can't use this channel, it's being deregistered */
1341                         spin_unlock_bh(&pch->downl);
1342                         pch->avail = 0;
1343                         if (--navail == 0)
1344                                 break;
1345                         continue;
1346                 }
1347
1348                 /*
1349                  * Create a fragment for this channel of
1350                  * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes.
1351                  * If mtu+2-hdrlen < 4, that is a ridiculously small
1352                  * MTU, so we use mtu = 2 + hdrlen.
1353                  */
1354                 if (fragsize > len)
1355                         fragsize = len;
1356                 flen = fragsize;
1357                 mtu = pch->chan->mtu + 2 - hdrlen;
1358                 if (mtu < 4)
1359                         mtu = 4;
1360                 if (flen > mtu)
1361                         flen = mtu;
1362                 if (flen == len && nfree == 0)
1363                         bits |= E;
1364                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1365                 if (!frag)
1366                         goto noskb;
1367                 q = skb_put(frag, flen + hdrlen);
1368
1369                 /* make the MP header */
1370                 q[0] = PPP_MP >> 8;
1371                 q[1] = PPP_MP;
1372                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1373                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1374                         q[3] = ppp->nxseq;
1375                 } else {
1376                         q[2] = bits;
1377                         q[3] = ppp->nxseq >> 16;
1378                         q[4] = ppp->nxseq >> 8;
1379                         q[5] = ppp->nxseq;
1380                 }
1381
1382                 /*
1383                  * Copy the data in.
1384                  * Unfortunately there is a bug in older versions of
1385                  * the Linux PPP multilink reconstruction code where it
1386                  * drops 0-length fragments.  Therefore we make sure the
1387                  * fragment has at least one byte of data.  Any bytes
1388                  * we add in this situation will end up as padding on the
1389                  * end of the reconstructed packet.
1390                  */
1391                 if (flen == 0)
1392                         *skb_put(frag, 1) = 0;
1393                 else
1394                         memcpy(q + hdrlen, p, flen);
1395
1396                 /* try to send it down the channel */
1397                 chan = pch->chan;
1398                 if (!skb_queue_empty(&pch->file.xq) ||
1399                     !chan->ops->start_xmit(chan, frag))
1400                         skb_queue_tail(&pch->file.xq, frag);
1401                 pch->had_frag = 1;
1402                 p += flen;
1403                 len -= flen;
1404                 ++ppp->nxseq;
1405                 bits = 0;
1406                 spin_unlock_bh(&pch->downl);
1407
1408                 if (--nbigger == 0 && fragsize > 0)
1409                         --fragsize;
1410         }
1411         ppp->nxchan = i;
1412
1413         return 1;
1414
1415  noskb:
1416         spin_unlock_bh(&pch->downl);
1417         if (ppp->debug & 1)
1418                 printk(KERN_ERR "PPP: no memory (fragment)\n");
1419         ++ppp->dev->stats.tx_errors;
1420         ++ppp->nxseq;
1421         return 1;       /* abandon the frame */
1422 }
1423 #endif /* CONFIG_PPP_MULTILINK */
1424
1425 /*
1426  * Try to send data out on a channel.
1427  */
1428 static void
1429 ppp_channel_push(struct channel *pch)
1430 {
1431         struct sk_buff *skb;
1432         struct ppp *ppp;
1433
1434         spin_lock_bh(&pch->downl);
1435         if (pch->chan) {
1436                 while (!skb_queue_empty(&pch->file.xq)) {
1437                         skb = skb_dequeue(&pch->file.xq);
1438                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1439                                 /* put the packet back and try again later */
1440                                 skb_queue_head(&pch->file.xq, skb);
1441                                 break;
1442                         }
1443                 }
1444         } else {
1445                 /* channel got deregistered */
1446                 skb_queue_purge(&pch->file.xq);
1447         }
1448         spin_unlock_bh(&pch->downl);
1449         /* see if there is anything from the attached unit to be sent */
1450         if (skb_queue_empty(&pch->file.xq)) {
1451                 read_lock_bh(&pch->upl);
1452                 ppp = pch->ppp;
1453                 if (ppp)
1454                         ppp_xmit_process(ppp);
1455                 read_unlock_bh(&pch->upl);
1456         }
1457 }
1458
1459 /*
1460  * Receive-side routines.
1461  */
1462
1463 /* misuse a few fields of the skb for MP reconstruction */
1464 #define sequence        priority
1465 #define BEbits          cb[0]
1466
1467 static inline void
1468 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1469 {
1470         ppp_recv_lock(ppp);
1471         /* ppp->dev == 0 means interface is closing down */
1472         if (ppp->dev)
1473                 ppp_receive_frame(ppp, skb, pch);
1474         else
1475                 kfree_skb(skb);
1476         ppp_recv_unlock(ppp);
1477 }
1478
1479 void
1480 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1481 {
1482         struct channel *pch = chan->ppp;
1483         int proto;
1484
1485         if (!pch || skb->len == 0) {
1486                 kfree_skb(skb);
1487                 return;
1488         }
1489
1490         proto = PPP_PROTO(skb);
1491         read_lock_bh(&pch->upl);
1492         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1493                 /* put it on the channel queue */
1494                 skb_queue_tail(&pch->file.rq, skb);
1495                 /* drop old frames if queue too long */
1496                 while (pch->file.rq.qlen > PPP_MAX_RQLEN
1497                        && (skb = skb_dequeue(&pch->file.rq)))
1498                         kfree_skb(skb);
1499                 wake_up_interruptible(&pch->file.rwait);
1500         } else {
1501                 ppp_do_recv(pch->ppp, skb, pch);
1502         }
1503         read_unlock_bh(&pch->upl);
1504 }
1505
1506 /* Put a 0-length skb in the receive queue as an error indication */
1507 void
1508 ppp_input_error(struct ppp_channel *chan, int code)
1509 {
1510         struct channel *pch = chan->ppp;
1511         struct sk_buff *skb;
1512
1513         if (!pch)
1514                 return;
1515
1516         read_lock_bh(&pch->upl);
1517         if (pch->ppp) {
1518                 skb = alloc_skb(0, GFP_ATOMIC);
1519                 if (skb) {
1520                         skb->len = 0;           /* probably unnecessary */
1521                         skb->cb[0] = code;
1522                         ppp_do_recv(pch->ppp, skb, pch);
1523                 }
1524         }
1525         read_unlock_bh(&pch->upl);
1526 }
1527
1528 /*
1529  * We come in here to process a received frame.
1530  * The receive side of the ppp unit is locked.
1531  */
1532 static void
1533 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1534 {
1535         if (pskb_may_pull(skb, 2)) {
1536 #ifdef CONFIG_PPP_MULTILINK
1537                 /* XXX do channel-level decompression here */
1538                 if (PPP_PROTO(skb) == PPP_MP)
1539                         ppp_receive_mp_frame(ppp, skb, pch);
1540                 else
1541 #endif /* CONFIG_PPP_MULTILINK */
1542                         ppp_receive_nonmp_frame(ppp, skb);
1543                 return;
1544         }
1545
1546         if (skb->len > 0)
1547                 /* note: a 0-length skb is used as an error indication */
1548                 ++ppp->dev->stats.rx_length_errors;
1549
1550         kfree_skb(skb);
1551         ppp_receive_error(ppp);
1552 }
1553
1554 static void
1555 ppp_receive_error(struct ppp *ppp)
1556 {
1557         ++ppp->dev->stats.rx_errors;
1558         if (ppp->vj)
1559                 slhc_toss(ppp->vj);
1560 }
1561
1562 static void
1563 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1564 {
1565         struct sk_buff *ns;
1566         int proto, len, npi;
1567
1568         /*
1569          * Decompress the frame, if compressed.
1570          * Note that some decompressors need to see uncompressed frames
1571          * that come in as well as compressed frames.
1572          */
1573         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
1574             && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1575                 skb = ppp_decompress_frame(ppp, skb);
1576
1577         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1578                 goto err;
1579
1580         proto = PPP_PROTO(skb);
1581         switch (proto) {
1582         case PPP_VJC_COMP:
1583                 /* decompress VJ compressed packets */
1584                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1585                         goto err;
1586
1587                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1588                         /* copy to a new sk_buff with more tailroom */
1589                         ns = dev_alloc_skb(skb->len + 128);
1590                         if (!ns) {
1591                                 printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1592                                 goto err;
1593                         }
1594                         skb_reserve(ns, 2);
1595                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1596                         kfree_skb(skb);
1597                         skb = ns;
1598                 }
1599                 else
1600                         skb->ip_summed = CHECKSUM_NONE;
1601
1602                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1603                 if (len <= 0) {
1604                         printk(KERN_DEBUG "PPP: VJ decompression error\n");
1605                         goto err;
1606                 }
1607                 len += 2;
1608                 if (len > skb->len)
1609                         skb_put(skb, len - skb->len);
1610                 else if (len < skb->len)
1611                         skb_trim(skb, len);
1612                 proto = PPP_IP;
1613                 break;
1614
1615         case PPP_VJC_UNCOMP:
1616                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1617                         goto err;
1618
1619                 /* Until we fix the decompressor need to make sure
1620                  * data portion is linear.
1621                  */
1622                 if (!pskb_may_pull(skb, skb->len))
1623                         goto err;
1624
1625                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1626                         printk(KERN_ERR "PPP: VJ uncompressed error\n");
1627                         goto err;
1628                 }
1629                 proto = PPP_IP;
1630                 break;
1631
1632         case PPP_CCP:
1633                 ppp_ccp_peek(ppp, skb, 1);
1634                 break;
1635         }
1636
1637         ++ppp->dev->stats.rx_packets;
1638         ppp->dev->stats.rx_bytes += skb->len - 2;
1639
1640         npi = proto_to_npindex(proto);
1641         if (npi < 0) {
1642                 /* control or unknown frame - pass it to pppd */
1643                 skb_queue_tail(&ppp->file.rq, skb);
1644                 /* limit queue length by dropping old frames */
1645                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1646                        && (skb = skb_dequeue(&ppp->file.rq)))
1647                         kfree_skb(skb);
1648                 /* wake up any process polling or blocking on read */
1649                 wake_up_interruptible(&ppp->file.rwait);
1650
1651         } else {
1652                 /* network protocol frame - give it to the kernel */
1653
1654 #ifdef CONFIG_PPP_FILTER
1655                 /* check if the packet passes the pass and active filters */
1656                 /* the filter instructions are constructed assuming
1657                    a four-byte PPP header on each packet */
1658                 if (ppp->pass_filter || ppp->active_filter) {
1659                         if (skb_cloned(skb) &&
1660                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1661                                 goto err;
1662
1663                         *skb_push(skb, 2) = 0;
1664                         if (ppp->pass_filter
1665                             && sk_run_filter(skb, ppp->pass_filter,
1666                                              ppp->pass_len) == 0) {
1667                                 if (ppp->debug & 1)
1668                                         printk(KERN_DEBUG "PPP: inbound frame "
1669                                                "not passed\n");
1670                                 kfree_skb(skb);
1671                                 return;
1672                         }
1673                         if (!(ppp->active_filter
1674                               && sk_run_filter(skb, ppp->active_filter,
1675                                                ppp->active_len) == 0))
1676                                 ppp->last_recv = jiffies;
1677                         __skb_pull(skb, 2);
1678                 } else
1679 #endif /* CONFIG_PPP_FILTER */
1680                         ppp->last_recv = jiffies;
1681
1682                 if ((ppp->dev->flags & IFF_UP) == 0
1683                     || ppp->npmode[npi] != NPMODE_PASS) {
1684                         kfree_skb(skb);
1685                 } else {
1686                         /* chop off protocol */
1687                         skb_pull_rcsum(skb, 2);
1688                         skb->dev = ppp->dev;
1689                         skb->protocol = htons(npindex_to_ethertype[npi]);
1690                         skb_reset_mac_header(skb);
1691                         netif_rx(skb);
1692                 }
1693         }
1694         return;
1695
1696  err:
1697         kfree_skb(skb);
1698         ppp_receive_error(ppp);
1699 }
1700
1701 static struct sk_buff *
1702 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1703 {
1704         int proto = PPP_PROTO(skb);
1705         struct sk_buff *ns;
1706         int len;
1707
1708         /* Until we fix all the decompressor's need to make sure
1709          * data portion is linear.
1710          */
1711         if (!pskb_may_pull(skb, skb->len))
1712                 goto err;
1713
1714         if (proto == PPP_COMP) {
1715                 int obuff_size;
1716
1717                 switch(ppp->rcomp->compress_proto) {
1718                 case CI_MPPE:
1719                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1720                         break;
1721                 default:
1722                         obuff_size = ppp->mru + PPP_HDRLEN;
1723                         break;
1724                 }
1725
1726                 ns = dev_alloc_skb(obuff_size);
1727                 if (!ns) {
1728                         printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1729                         goto err;
1730                 }
1731                 /* the decompressor still expects the A/C bytes in the hdr */
1732                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1733                                 skb->len + 2, ns->data, obuff_size);
1734                 if (len < 0) {
1735                         /* Pass the compressed frame to pppd as an
1736                            error indication. */
1737                         if (len == DECOMP_FATALERROR)
1738                                 ppp->rstate |= SC_DC_FERROR;
1739                         kfree_skb(ns);
1740                         goto err;
1741                 }
1742
1743                 kfree_skb(skb);
1744                 skb = ns;
1745                 skb_put(skb, len);
1746                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1747
1748         } else {
1749                 /* Uncompressed frame - pass to decompressor so it
1750                    can update its dictionary if necessary. */
1751                 if (ppp->rcomp->incomp)
1752                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1753                                            skb->len + 2);
1754         }
1755
1756         return skb;
1757
1758  err:
1759         ppp->rstate |= SC_DC_ERROR;
1760         ppp_receive_error(ppp);
1761         return skb;
1762 }
1763
1764 #ifdef CONFIG_PPP_MULTILINK
1765 /*
1766  * Receive a multilink frame.
1767  * We put it on the reconstruction queue and then pull off
1768  * as many completed frames as we can.
1769  */
1770 static void
1771 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1772 {
1773         u32 mask, seq;
1774         struct channel *ch;
1775         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1776
1777         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1778                 goto err;               /* no good, throw it away */
1779
1780         /* Decode sequence number and begin/end bits */
1781         if (ppp->flags & SC_MP_SHORTSEQ) {
1782                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1783                 mask = 0xfff;
1784         } else {
1785                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1786                 mask = 0xffffff;
1787         }
1788         skb->BEbits = skb->data[2];
1789         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1790
1791         /*
1792          * Do protocol ID decompression on the first fragment of each packet.
1793          */
1794         if ((skb->BEbits & B) && (skb->data[0] & 1))
1795                 *skb_push(skb, 1) = 0;
1796
1797         /*
1798          * Expand sequence number to 32 bits, making it as close
1799          * as possible to ppp->minseq.
1800          */
1801         seq |= ppp->minseq & ~mask;
1802         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1803                 seq += mask + 1;
1804         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1805                 seq -= mask + 1;        /* should never happen */
1806         skb->sequence = seq;
1807         pch->lastseq = seq;
1808
1809         /*
1810          * If this packet comes before the next one we were expecting,
1811          * drop it.
1812          */
1813         if (seq_before(seq, ppp->nextseq)) {
1814                 kfree_skb(skb);
1815                 ++ppp->dev->stats.rx_dropped;
1816                 ppp_receive_error(ppp);
1817                 return;
1818         }
1819
1820         /*
1821          * Reevaluate minseq, the minimum over all channels of the
1822          * last sequence number received on each channel.  Because of
1823          * the increasing sequence number rule, we know that any fragment
1824          * before `minseq' which hasn't arrived is never going to arrive.
1825          * The list of channels can't change because we have the receive
1826          * side of the ppp unit locked.
1827          */
1828         list_for_each_entry(ch, &ppp->channels, clist) {
1829                 if (seq_before(ch->lastseq, seq))
1830                         seq = ch->lastseq;
1831         }
1832         if (seq_before(ppp->minseq, seq))
1833                 ppp->minseq = seq;
1834
1835         /* Put the fragment on the reconstruction queue */
1836         ppp_mp_insert(ppp, skb);
1837
1838         /* If the queue is getting long, don't wait any longer for packets
1839            before the start of the queue. */
1840         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1841                 struct sk_buff *skb = skb_peek(&ppp->mrq);
1842                 if (seq_before(ppp->minseq, skb->sequence))
1843                         ppp->minseq = skb->sequence;
1844         }
1845
1846         /* Pull completed packets off the queue and receive them. */
1847         while ((skb = ppp_mp_reconstruct(ppp)))
1848                 ppp_receive_nonmp_frame(ppp, skb);
1849
1850         return;
1851
1852  err:
1853         kfree_skb(skb);
1854         ppp_receive_error(ppp);
1855 }
1856
1857 /*
1858  * Insert a fragment on the MP reconstruction queue.
1859  * The queue is ordered by increasing sequence number.
1860  */
1861 static void
1862 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1863 {
1864         struct sk_buff *p;
1865         struct sk_buff_head *list = &ppp->mrq;
1866         u32 seq = skb->sequence;
1867
1868         /* N.B. we don't need to lock the list lock because we have the
1869            ppp unit receive-side lock. */
1870         skb_queue_walk(list, p) {
1871                 if (seq_before(seq, p->sequence))
1872                         break;
1873         }
1874         __skb_queue_before(list, p, skb);
1875 }
1876
1877 /*
1878  * Reconstruct a packet from the MP fragment queue.
1879  * We go through increasing sequence numbers until we find a
1880  * complete packet, or we get to the sequence number for a fragment
1881  * which hasn't arrived but might still do so.
1882  */
1883 static struct sk_buff *
1884 ppp_mp_reconstruct(struct ppp *ppp)
1885 {
1886         u32 seq = ppp->nextseq;
1887         u32 minseq = ppp->minseq;
1888         struct sk_buff_head *list = &ppp->mrq;
1889         struct sk_buff *p, *next;
1890         struct sk_buff *head, *tail;
1891         struct sk_buff *skb = NULL;
1892         int lost = 0, len = 0;
1893
1894         if (ppp->mrru == 0)     /* do nothing until mrru is set */
1895                 return NULL;
1896         head = list->next;
1897         tail = NULL;
1898         for (p = head; p != (struct sk_buff *) list; p = next) {
1899                 next = p->next;
1900                 if (seq_before(p->sequence, seq)) {
1901                         /* this can't happen, anyway ignore the skb */
1902                         printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
1903                                p->sequence, seq);
1904                         head = next;
1905                         continue;
1906                 }
1907                 if (p->sequence != seq) {
1908                         /* Fragment `seq' is missing.  If it is after
1909                            minseq, it might arrive later, so stop here. */
1910                         if (seq_after(seq, minseq))
1911                                 break;
1912                         /* Fragment `seq' is lost, keep going. */
1913                         lost = 1;
1914                         seq = seq_before(minseq, p->sequence)?
1915                                 minseq + 1: p->sequence;
1916                         next = p;
1917                         continue;
1918                 }
1919
1920                 /*
1921                  * At this point we know that all the fragments from
1922                  * ppp->nextseq to seq are either present or lost.
1923                  * Also, there are no complete packets in the queue
1924                  * that have no missing fragments and end before this
1925                  * fragment.
1926                  */
1927
1928                 /* B bit set indicates this fragment starts a packet */
1929                 if (p->BEbits & B) {
1930                         head = p;
1931                         lost = 0;
1932                         len = 0;
1933                 }
1934
1935                 len += p->len;
1936
1937                 /* Got a complete packet yet? */
1938                 if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
1939                         if (len > ppp->mrru + 2) {
1940                                 ++ppp->dev->stats.rx_length_errors;
1941                                 printk(KERN_DEBUG "PPP: reconstructed packet"
1942                                        " is too long (%d)\n", len);
1943                         } else if (p == head) {
1944                                 /* fragment is complete packet - reuse skb */
1945                                 tail = p;
1946                                 skb = skb_get(p);
1947                                 break;
1948                         } else if ((skb = dev_alloc_skb(len)) == NULL) {
1949                                 ++ppp->dev->stats.rx_missed_errors;
1950                                 printk(KERN_DEBUG "PPP: no memory for "
1951                                        "reconstructed packet");
1952                         } else {
1953                                 tail = p;
1954                                 break;
1955                         }
1956                         ppp->nextseq = seq + 1;
1957                 }
1958
1959                 /*
1960                  * If this is the ending fragment of a packet,
1961                  * and we haven't found a complete valid packet yet,
1962                  * we can discard up to and including this fragment.
1963                  */
1964                 if (p->BEbits & E)
1965                         head = next;
1966
1967                 ++seq;
1968         }
1969
1970         /* If we have a complete packet, copy it all into one skb. */
1971         if (tail != NULL) {
1972                 /* If we have discarded any fragments,
1973                    signal a receive error. */
1974                 if (head->sequence != ppp->nextseq) {
1975                         if (ppp->debug & 1)
1976                                 printk(KERN_DEBUG "  missed pkts %u..%u\n",
1977                                        ppp->nextseq, head->sequence-1);
1978                         ++ppp->dev->stats.rx_dropped;
1979                         ppp_receive_error(ppp);
1980                 }
1981
1982                 if (head != tail)
1983                         /* copy to a single skb */
1984                         for (p = head; p != tail->next; p = p->next)
1985                                 skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
1986                 ppp->nextseq = tail->sequence + 1;
1987                 head = tail->next;
1988         }
1989
1990         /* Discard all the skbuffs that we have copied the data out of
1991            or that we can't use. */
1992         while ((p = list->next) != head) {
1993                 __skb_unlink(p, list);
1994                 kfree_skb(p);
1995         }
1996
1997         return skb;
1998 }
1999 #endif /* CONFIG_PPP_MULTILINK */
2000
2001 /*
2002  * Channel interface.
2003  */
2004
2005 /*
2006  * Create a new, unattached ppp channel.
2007  */
2008 int
2009 ppp_register_channel(struct ppp_channel *chan)
2010 {
2011         struct channel *pch;
2012
2013         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2014         if (!pch)
2015                 return -ENOMEM;
2016         pch->ppp = NULL;
2017         pch->chan = chan;
2018         chan->ppp = pch;
2019         init_ppp_file(&pch->file, CHANNEL);
2020         pch->file.hdrlen = chan->hdrlen;
2021 #ifdef CONFIG_PPP_MULTILINK
2022         pch->lastseq = -1;
2023 #endif /* CONFIG_PPP_MULTILINK */
2024         init_rwsem(&pch->chan_sem);
2025         spin_lock_init(&pch->downl);
2026         rwlock_init(&pch->upl);
2027         spin_lock_bh(&all_channels_lock);
2028         pch->file.index = ++last_channel_index;
2029         list_add(&pch->list, &new_channels);
2030         atomic_inc(&channel_count);
2031         spin_unlock_bh(&all_channels_lock);
2032         return 0;
2033 }
2034
2035 /*
2036  * Return the index of a channel.
2037  */
2038 int ppp_channel_index(struct ppp_channel *chan)
2039 {
2040         struct channel *pch = chan->ppp;
2041
2042         if (pch)
2043                 return pch->file.index;
2044         return -1;
2045 }
2046
2047 /*
2048  * Return the PPP unit number to which a channel is connected.
2049  */
2050 int ppp_unit_number(struct ppp_channel *chan)
2051 {
2052         struct channel *pch = chan->ppp;
2053         int unit = -1;
2054
2055         if (pch) {
2056                 read_lock_bh(&pch->upl);
2057                 if (pch->ppp)
2058                         unit = pch->ppp->file.index;
2059                 read_unlock_bh(&pch->upl);
2060         }
2061         return unit;
2062 }
2063
2064 /*
2065  * Disconnect a channel from the generic layer.
2066  * This must be called in process context.
2067  */
2068 void
2069 ppp_unregister_channel(struct ppp_channel *chan)
2070 {
2071         struct channel *pch = chan->ppp;
2072
2073         if (!pch)
2074                 return;         /* should never happen */
2075         chan->ppp = NULL;
2076
2077         /*
2078          * This ensures that we have returned from any calls into the
2079          * the channel's start_xmit or ioctl routine before we proceed.
2080          */
2081         down_write(&pch->chan_sem);
2082         spin_lock_bh(&pch->downl);
2083         pch->chan = NULL;
2084         spin_unlock_bh(&pch->downl);
2085         up_write(&pch->chan_sem);
2086         ppp_disconnect_channel(pch);
2087         spin_lock_bh(&all_channels_lock);
2088         list_del(&pch->list);
2089         spin_unlock_bh(&all_channels_lock);
2090         pch->file.dead = 1;
2091         wake_up_interruptible(&pch->file.rwait);
2092         if (atomic_dec_and_test(&pch->file.refcnt))
2093                 ppp_destroy_channel(pch);
2094 }
2095
2096 /*
2097  * Callback from a channel when it can accept more to transmit.
2098  * This should be called at BH/softirq level, not interrupt level.
2099  */
2100 void
2101 ppp_output_wakeup(struct ppp_channel *chan)
2102 {
2103         struct channel *pch = chan->ppp;
2104
2105         if (!pch)
2106                 return;
2107         ppp_channel_push(pch);
2108 }
2109
2110 /*
2111  * Compression control.
2112  */
2113
2114 /* Process the PPPIOCSCOMPRESS ioctl. */
2115 static int
2116 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2117 {
2118         int err;
2119         struct compressor *cp, *ocomp;
2120         struct ppp_option_data data;
2121         void *state, *ostate;
2122         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2123
2124         err = -EFAULT;
2125         if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2126             || (data.length <= CCP_MAX_OPTION_LENGTH
2127                 && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2128                 goto out;
2129         err = -EINVAL;
2130         if (data.length > CCP_MAX_OPTION_LENGTH
2131             || ccp_option[1] < 2 || ccp_option[1] > data.length)
2132                 goto out;
2133
2134         cp = try_then_request_module(
2135                 find_compressor(ccp_option[0]),
2136                 "ppp-compress-%d", ccp_option[0]);
2137         if (!cp)
2138                 goto out;
2139
2140         err = -ENOBUFS;
2141         if (data.transmit) {
2142                 state = cp->comp_alloc(ccp_option, data.length);
2143                 if (state) {
2144                         ppp_xmit_lock(ppp);
2145                         ppp->xstate &= ~SC_COMP_RUN;
2146                         ocomp = ppp->xcomp;
2147                         ostate = ppp->xc_state;
2148                         ppp->xcomp = cp;
2149                         ppp->xc_state = state;
2150                         ppp_xmit_unlock(ppp);
2151                         if (ostate) {
2152                                 ocomp->comp_free(ostate);
2153                                 module_put(ocomp->owner);
2154                         }
2155                         err = 0;
2156                 } else
2157                         module_put(cp->owner);
2158
2159         } else {
2160                 state = cp->decomp_alloc(ccp_option, data.length);
2161                 if (state) {
2162                         ppp_recv_lock(ppp);
2163                         ppp->rstate &= ~SC_DECOMP_RUN;
2164                         ocomp = ppp->rcomp;
2165                         ostate = ppp->rc_state;
2166                         ppp->rcomp = cp;
2167                         ppp->rc_state = state;
2168                         ppp_recv_unlock(ppp);
2169                         if (ostate) {
2170                                 ocomp->decomp_free(ostate);
2171                                 module_put(ocomp->owner);
2172                         }
2173                         err = 0;
2174                 } else
2175                         module_put(cp->owner);
2176         }
2177
2178  out:
2179         return err;
2180 }
2181
2182 /*
2183  * Look at a CCP packet and update our state accordingly.
2184  * We assume the caller has the xmit or recv path locked.
2185  */
2186 static void
2187 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2188 {
2189         unsigned char *dp;
2190         int len;
2191
2192         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2193                 return; /* no header */
2194         dp = skb->data + 2;
2195
2196         switch (CCP_CODE(dp)) {
2197         case CCP_CONFREQ:
2198
2199                 /* A ConfReq starts negotiation of compression
2200                  * in one direction of transmission,
2201                  * and hence brings it down...but which way?
2202                  *
2203                  * Remember:
2204                  * A ConfReq indicates what the sender would like to receive
2205                  */
2206                 if(inbound)
2207                         /* He is proposing what I should send */
2208                         ppp->xstate &= ~SC_COMP_RUN;
2209                 else
2210                         /* I am proposing to what he should send */
2211                         ppp->rstate &= ~SC_DECOMP_RUN;
2212
2213                 break;
2214
2215         case CCP_TERMREQ:
2216         case CCP_TERMACK:
2217                 /*
2218                  * CCP is going down, both directions of transmission
2219                  */
2220                 ppp->rstate &= ~SC_DECOMP_RUN;
2221                 ppp->xstate &= ~SC_COMP_RUN;
2222                 break;
2223
2224         case CCP_CONFACK:
2225                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2226                         break;
2227                 len = CCP_LENGTH(dp);
2228                 if (!pskb_may_pull(skb, len + 2))
2229                         return;         /* too short */
2230                 dp += CCP_HDRLEN;
2231                 len -= CCP_HDRLEN;
2232                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2233                         break;
2234                 if (inbound) {
2235                         /* we will start receiving compressed packets */
2236                         if (!ppp->rc_state)
2237                                 break;
2238                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2239                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2240                                 ppp->rstate |= SC_DECOMP_RUN;
2241                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2242                         }
2243                 } else {
2244                         /* we will soon start sending compressed packets */
2245                         if (!ppp->xc_state)
2246                                 break;
2247                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2248                                         ppp->file.index, 0, ppp->debug))
2249                                 ppp->xstate |= SC_COMP_RUN;
2250                 }
2251                 break;
2252
2253         case CCP_RESETACK:
2254                 /* reset the [de]compressor */
2255                 if ((ppp->flags & SC_CCP_UP) == 0)
2256                         break;
2257                 if (inbound) {
2258                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2259                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2260                                 ppp->rstate &= ~SC_DC_ERROR;
2261                         }
2262                 } else {
2263                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2264                                 ppp->xcomp->comp_reset(ppp->xc_state);
2265                 }
2266                 break;
2267         }
2268 }
2269
2270 /* Free up compression resources. */
2271 static void
2272 ppp_ccp_closed(struct ppp *ppp)
2273 {
2274         void *xstate, *rstate;
2275         struct compressor *xcomp, *rcomp;
2276
2277         ppp_lock(ppp);
2278         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2279         ppp->xstate = 0;
2280         xcomp = ppp->xcomp;
2281         xstate = ppp->xc_state;
2282         ppp->xc_state = NULL;
2283         ppp->rstate = 0;
2284         rcomp = ppp->rcomp;
2285         rstate = ppp->rc_state;
2286         ppp->rc_state = NULL;
2287         ppp_unlock(ppp);
2288
2289         if (xstate) {
2290                 xcomp->comp_free(xstate);
2291                 module_put(xcomp->owner);
2292         }
2293         if (rstate) {
2294                 rcomp->decomp_free(rstate);
2295                 module_put(rcomp->owner);
2296         }
2297 }
2298
2299 /* List of compressors. */
2300 static LIST_HEAD(compressor_list);
2301 static DEFINE_SPINLOCK(compressor_list_lock);
2302
2303 struct compressor_entry {
2304         struct list_head list;
2305         struct compressor *comp;
2306 };
2307
2308 static struct compressor_entry *
2309 find_comp_entry(int proto)
2310 {
2311         struct compressor_entry *ce;
2312
2313         list_for_each_entry(ce, &compressor_list, list) {
2314                 if (ce->comp->compress_proto == proto)
2315                         return ce;
2316         }
2317         return NULL;
2318 }
2319
2320 /* Register a compressor */
2321 int
2322 ppp_register_compressor(struct compressor *cp)
2323 {
2324         struct compressor_entry *ce;
2325         int ret;
2326         spin_lock(&compressor_list_lock);
2327         ret = -EEXIST;
2328         if (find_comp_entry(cp->compress_proto))
2329                 goto out;
2330         ret = -ENOMEM;
2331         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2332         if (!ce)
2333                 goto out;
2334         ret = 0;
2335         ce->comp = cp;
2336         list_add(&ce->list, &compressor_list);
2337  out:
2338         spin_unlock(&compressor_list_lock);
2339         return ret;
2340 }
2341
2342 /* Unregister a compressor */
2343 void
2344 ppp_unregister_compressor(struct compressor *cp)
2345 {
2346         struct compressor_entry *ce;
2347
2348         spin_lock(&compressor_list_lock);
2349         ce = find_comp_entry(cp->compress_proto);
2350         if (ce && ce->comp == cp) {
2351                 list_del(&ce->list);
2352                 kfree(ce);
2353         }
2354         spin_unlock(&compressor_list_lock);
2355 }
2356
2357 /* Find a compressor. */
2358 static struct compressor *
2359 find_compressor(int type)
2360 {
2361         struct compressor_entry *ce;
2362         struct compressor *cp = NULL;
2363
2364         spin_lock(&compressor_list_lock);
2365         ce = find_comp_entry(type);
2366         if (ce) {
2367                 cp = ce->comp;
2368                 if (!try_module_get(cp->owner))
2369                         cp = NULL;
2370         }
2371         spin_unlock(&compressor_list_lock);
2372         return cp;
2373 }
2374
2375 /*
2376  * Miscelleneous stuff.
2377  */
2378
2379 static void
2380 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2381 {
2382         struct slcompress *vj = ppp->vj;
2383
2384         memset(st, 0, sizeof(*st));
2385         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2386         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2387         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2388         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2389         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2390         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2391         if (!vj)
2392                 return;
2393         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2394         st->vj.vjs_compressed = vj->sls_o_compressed;
2395         st->vj.vjs_searches = vj->sls_o_searches;
2396         st->vj.vjs_misses = vj->sls_o_misses;
2397         st->vj.vjs_errorin = vj->sls_i_error;
2398         st->vj.vjs_tossed = vj->sls_i_tossed;
2399         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2400         st->vj.vjs_compressedin = vj->sls_i_compressed;
2401 }
2402
2403 /*
2404  * Stuff for handling the lists of ppp units and channels
2405  * and for initialization.
2406  */
2407
2408 /*
2409  * Create a new ppp interface unit.  Fails if it can't allocate memory
2410  * or if there is already a unit with the requested number.
2411  * unit == -1 means allocate a new number.
2412  */
2413 static struct ppp *
2414 ppp_create_interface(int unit, int *retp)
2415 {
2416         struct ppp *ppp;
2417         struct net_device *dev = NULL;
2418         int ret = -ENOMEM;
2419         int i;
2420
2421         ppp = kzalloc(sizeof(struct ppp), GFP_KERNEL);
2422         if (!ppp)
2423                 goto out;
2424         dev = alloc_netdev(0, "", ppp_setup);
2425         if (!dev)
2426                 goto out1;
2427
2428         ppp->mru = PPP_MRU;
2429         init_ppp_file(&ppp->file, INTERFACE);
2430         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2431         for (i = 0; i < NUM_NP; ++i)
2432                 ppp->npmode[i] = NPMODE_PASS;
2433         INIT_LIST_HEAD(&ppp->channels);
2434         spin_lock_init(&ppp->rlock);
2435         spin_lock_init(&ppp->wlock);
2436 #ifdef CONFIG_PPP_MULTILINK
2437         ppp->minseq = -1;
2438         skb_queue_head_init(&ppp->mrq);
2439 #endif /* CONFIG_PPP_MULTILINK */
2440         ppp->dev = dev;
2441         dev->priv = ppp;
2442
2443         dev->hard_start_xmit = ppp_start_xmit;
2444
2445         ret = -EEXIST;
2446         mutex_lock(&all_ppp_mutex);
2447         if (unit < 0)
2448                 unit = cardmap_find_first_free(all_ppp_units);
2449         else if (cardmap_get(all_ppp_units, unit) != NULL)
2450                 goto out2;      /* unit already exists */
2451
2452         /* Initialize the new ppp unit */
2453         ppp->file.index = unit;
2454         sprintf(dev->name, "ppp%d", unit);
2455
2456         ret = register_netdev(dev);
2457         if (ret != 0) {
2458                 printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2459                        dev->name, ret);
2460                 goto out2;
2461         }
2462
2463         atomic_inc(&ppp_unit_count);
2464         ret = cardmap_set(&all_ppp_units, unit, ppp);
2465         if (ret != 0)
2466                 goto out3;
2467
2468         mutex_unlock(&all_ppp_mutex);
2469         *retp = 0;
2470         return ppp;
2471
2472 out3:
2473         atomic_dec(&ppp_unit_count);
2474         unregister_netdev(dev);
2475 out2:
2476         mutex_unlock(&all_ppp_mutex);
2477         free_netdev(dev);
2478 out1:
2479         kfree(ppp);
2480 out:
2481         *retp = ret;
2482         return NULL;
2483 }
2484
2485 /*
2486  * Initialize a ppp_file structure.
2487  */
2488 static void
2489 init_ppp_file(struct ppp_file *pf, int kind)
2490 {
2491         pf->kind = kind;
2492         skb_queue_head_init(&pf->xq);
2493         skb_queue_head_init(&pf->rq);
2494         atomic_set(&pf->refcnt, 1);
2495         init_waitqueue_head(&pf->rwait);
2496 }
2497
2498 /*
2499  * Take down a ppp interface unit - called when the owning file
2500  * (the one that created the unit) is closed or detached.
2501  */
2502 static void ppp_shutdown_interface(struct ppp *ppp)
2503 {
2504         struct net_device *dev;
2505
2506         mutex_lock(&all_ppp_mutex);
2507         ppp_lock(ppp);
2508         dev = ppp->dev;
2509         ppp->dev = NULL;
2510         ppp_unlock(ppp);
2511         /* This will call dev_close() for us. */
2512         if (dev) {
2513                 unregister_netdev(dev);
2514                 free_netdev(dev);
2515         }
2516         cardmap_set(&all_ppp_units, ppp->file.index, NULL);
2517         ppp->file.dead = 1;
2518         ppp->owner = NULL;
2519         wake_up_interruptible(&ppp->file.rwait);
2520         mutex_unlock(&all_ppp_mutex);
2521 }
2522
2523 /*
2524  * Free the memory used by a ppp unit.  This is only called once
2525  * there are no channels connected to the unit and no file structs
2526  * that reference the unit.
2527  */
2528 static void ppp_destroy_interface(struct ppp *ppp)
2529 {
2530         atomic_dec(&ppp_unit_count);
2531
2532         if (!ppp->file.dead || ppp->n_channels) {
2533                 /* "can't happen" */
2534                 printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2535                        "n_channels=%d !\n", ppp, ppp->file.dead,
2536                        ppp->n_channels);
2537                 return;
2538         }
2539
2540         ppp_ccp_closed(ppp);
2541         if (ppp->vj) {
2542                 slhc_free(ppp->vj);
2543                 ppp->vj = NULL;
2544         }
2545         skb_queue_purge(&ppp->file.xq);
2546         skb_queue_purge(&ppp->file.rq);
2547 #ifdef CONFIG_PPP_MULTILINK
2548         skb_queue_purge(&ppp->mrq);
2549 #endif /* CONFIG_PPP_MULTILINK */
2550 #ifdef CONFIG_PPP_FILTER
2551         kfree(ppp->pass_filter);
2552         ppp->pass_filter = NULL;
2553         kfree(ppp->active_filter);
2554         ppp->active_filter = NULL;
2555 #endif /* CONFIG_PPP_FILTER */
2556
2557         if (ppp->xmit_pending)
2558                 kfree_skb(ppp->xmit_pending);
2559
2560         kfree(ppp);
2561 }
2562
2563 /*
2564  * Locate an existing ppp unit.
2565  * The caller should have locked the all_ppp_mutex.
2566  */
2567 static struct ppp *
2568 ppp_find_unit(int unit)
2569 {
2570         return cardmap_get(all_ppp_units, unit);
2571 }
2572
2573 /*
2574  * Locate an existing ppp channel.
2575  * The caller should have locked the all_channels_lock.
2576  * First we look in the new_channels list, then in the
2577  * all_channels list.  If found in the new_channels list,
2578  * we move it to the all_channels list.  This is for speed
2579  * when we have a lot of channels in use.
2580  */
2581 static struct channel *
2582 ppp_find_channel(int unit)
2583 {
2584         struct channel *pch;
2585
2586         list_for_each_entry(pch, &new_channels, list) {
2587                 if (pch->file.index == unit) {
2588                         list_move(&pch->list, &all_channels);
2589                         return pch;
2590                 }
2591         }
2592         list_for_each_entry(pch, &all_channels, list) {
2593                 if (pch->file.index == unit)
2594                         return pch;
2595         }
2596         return NULL;
2597 }
2598
2599 /*
2600  * Connect a PPP channel to a PPP interface unit.
2601  */
2602 static int
2603 ppp_connect_channel(struct channel *pch, int unit)
2604 {
2605         struct ppp *ppp;
2606         int ret = -ENXIO;
2607         int hdrlen;
2608
2609         mutex_lock(&all_ppp_mutex);
2610         ppp = ppp_find_unit(unit);
2611         if (!ppp)
2612                 goto out;
2613         write_lock_bh(&pch->upl);
2614         ret = -EINVAL;
2615         if (pch->ppp)
2616                 goto outl;
2617
2618         ppp_lock(ppp);
2619         if (pch->file.hdrlen > ppp->file.hdrlen)
2620                 ppp->file.hdrlen = pch->file.hdrlen;
2621         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2622         if (ppp->dev && hdrlen > ppp->dev->hard_header_len)
2623                 ppp->dev->hard_header_len = hdrlen;
2624         list_add_tail(&pch->clist, &ppp->channels);
2625         ++ppp->n_channels;
2626         pch->ppp = ppp;
2627         atomic_inc(&ppp->file.refcnt);
2628         ppp_unlock(ppp);
2629         ret = 0;
2630
2631  outl:
2632         write_unlock_bh(&pch->upl);
2633  out:
2634         mutex_unlock(&all_ppp_mutex);
2635         return ret;
2636 }
2637
2638 /*
2639  * Disconnect a channel from its ppp unit.
2640  */
2641 static int
2642 ppp_disconnect_channel(struct channel *pch)
2643 {
2644         struct ppp *ppp;
2645         int err = -EINVAL;
2646
2647         write_lock_bh(&pch->upl);
2648         ppp = pch->ppp;
2649         pch->ppp = NULL;
2650         write_unlock_bh(&pch->upl);
2651         if (ppp) {
2652                 /* remove it from the ppp unit's list */
2653                 ppp_lock(ppp);
2654                 list_del(&pch->clist);
2655                 if (--ppp->n_channels == 0)
2656                         wake_up_interruptible(&ppp->file.rwait);
2657                 ppp_unlock(ppp);
2658                 if (atomic_dec_and_test(&ppp->file.refcnt))
2659                         ppp_destroy_interface(ppp);
2660                 err = 0;
2661         }
2662         return err;
2663 }
2664
2665 /*
2666  * Free up the resources used by a ppp channel.
2667  */
2668 static void ppp_destroy_channel(struct channel *pch)
2669 {
2670         atomic_dec(&channel_count);
2671
2672         if (!pch->file.dead) {
2673                 /* "can't happen" */
2674                 printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2675                        pch);
2676                 return;
2677         }
2678         skb_queue_purge(&pch->file.xq);
2679         skb_queue_purge(&pch->file.rq);
2680         kfree(pch);
2681 }
2682
2683 static void __exit ppp_cleanup(void)
2684 {
2685         /* should never happen */
2686         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2687                 printk(KERN_ERR "PPP: removing module but units remain!\n");
2688         cardmap_destroy(&all_ppp_units);
2689         unregister_chrdev(PPP_MAJOR, "ppp");
2690         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2691         class_destroy(ppp_class);
2692 }
2693
2694 /*
2695  * Cardmap implementation.
2696  */
2697 static void *cardmap_get(struct cardmap *map, unsigned int nr)
2698 {
2699         struct cardmap *p;
2700         int i;
2701
2702         for (p = map; p != NULL; ) {
2703                 if ((i = nr >> p->shift) >= CARDMAP_WIDTH)
2704                         return NULL;
2705                 if (p->shift == 0)
2706                         return p->ptr[i];
2707                 nr &= ~(CARDMAP_MASK << p->shift);
2708                 p = p->ptr[i];
2709         }
2710         return NULL;
2711 }
2712
2713 static int cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr)
2714 {
2715         struct cardmap *p;
2716         int i;
2717
2718         p = *pmap;
2719         if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) {
2720                 do {
2721                         /* need a new top level */
2722                         struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL);
2723                         if (!np)
2724                                 goto enomem;
2725                         np->ptr[0] = p;
2726                         if (p != NULL) {
2727                                 np->shift = p->shift + CARDMAP_ORDER;
2728                                 p->parent = np;
2729                         } else
2730                                 np->shift = 0;
2731                         p = np;
2732                 } while ((nr >> p->shift) >= CARDMAP_WIDTH);
2733                 *pmap = p;
2734         }
2735         while (p->shift > 0) {
2736                 i = (nr >> p->shift) & CARDMAP_MASK;
2737                 if (p->ptr[i] == NULL) {
2738                         struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL);
2739                         if (!np)
2740                                 goto enomem;
2741                         np->shift = p->shift - CARDMAP_ORDER;
2742                         np->parent = p;
2743                         p->ptr[i] = np;
2744                 }
2745                 if (ptr == NULL)
2746                         clear_bit(i, &p->inuse);
2747                 p = p->ptr[i];
2748         }
2749         i = nr & CARDMAP_MASK;
2750         p->ptr[i] = ptr;
2751         if (ptr != NULL)
2752                 set_bit(i, &p->inuse);
2753         else
2754                 clear_bit(i, &p->inuse);
2755         return 0;
2756  enomem:
2757         return -ENOMEM;
2758 }
2759
2760 static unsigned int cardmap_find_first_free(struct cardmap *map)
2761 {
2762         struct cardmap *p;
2763         unsigned int nr = 0;
2764         int i;
2765
2766         if ((p = map) == NULL)
2767                 return 0;
2768         for (;;) {
2769                 i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH);
2770                 if (i >= CARDMAP_WIDTH) {
2771                         if (p->parent == NULL)
2772                                 return CARDMAP_WIDTH << p->shift;
2773                         p = p->parent;
2774                         i = (nr >> p->shift) & CARDMAP_MASK;
2775                         set_bit(i, &p->inuse);
2776                         continue;
2777                 }
2778                 nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift);
2779                 if (p->shift == 0 || p->ptr[i] == NULL)
2780                         return nr;
2781                 p = p->ptr[i];
2782         }
2783 }
2784
2785 static void cardmap_destroy(struct cardmap **pmap)
2786 {
2787         struct cardmap *p, *np;
2788         int i;
2789
2790         for (p = *pmap; p != NULL; p = np) {
2791                 if (p->shift != 0) {
2792                         for (i = 0; i < CARDMAP_WIDTH; ++i)
2793                                 if (p->ptr[i] != NULL)
2794                                         break;
2795                         if (i < CARDMAP_WIDTH) {
2796                                 np = p->ptr[i];
2797                                 p->ptr[i] = NULL;
2798                                 continue;
2799                         }
2800                 }
2801                 np = p->parent;
2802                 kfree(p);
2803         }
2804         *pmap = NULL;
2805 }
2806
2807 /* Module/initialization stuff */
2808
2809 module_init(ppp_init);
2810 module_exit(ppp_cleanup);
2811
2812 EXPORT_SYMBOL(ppp_register_channel);
2813 EXPORT_SYMBOL(ppp_unregister_channel);
2814 EXPORT_SYMBOL(ppp_channel_index);
2815 EXPORT_SYMBOL(ppp_unit_number);
2816 EXPORT_SYMBOL(ppp_input);
2817 EXPORT_SYMBOL(ppp_input_error);
2818 EXPORT_SYMBOL(ppp_output_wakeup);
2819 EXPORT_SYMBOL(ppp_register_compressor);
2820 EXPORT_SYMBOL(ppp_unregister_compressor);
2821 MODULE_LICENSE("GPL");
2822 MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2823 MODULE_ALIAS("/dev/ppp");