net: wireless: bcmdhd: Enable wlan access on resume for all sdio functions
[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/idr.h>
31 #include <linux/netdevice.h>
32 #include <linux/poll.h>
33 #include <linux/ppp_defs.h>
34 #include <linux/filter.h>
35 #include <linux/if_ppp.h>
36 #include <linux/ppp_channel.h>
37 #include <linux/ppp-comp.h>
38 #include <linux/skbuff.h>
39 #include <linux/rtnetlink.h>
40 #include <linux/if_arp.h>
41 #include <linux/ip.h>
42 #include <linux/tcp.h>
43 #include <linux/spinlock.h>
44 #include <linux/rwsem.h>
45 #include <linux/stddef.h>
46 #include <linux/device.h>
47 #include <linux/mutex.h>
48 #include <linux/slab.h>
49 #include <asm/unaligned.h>
50 #include <net/slhc_vj.h>
51 #include <linux/atomic.h>
52
53 #include <linux/nsproxy.h>
54 #include <net/net_namespace.h>
55 #include <net/netns/generic.h>
56
57 #define PPP_VERSION     "2.4.2"
58
59 /*
60  * Network protocols we support.
61  */
62 #define NP_IP   0               /* Internet Protocol V4 */
63 #define NP_IPV6 1               /* Internet Protocol V6 */
64 #define NP_IPX  2               /* IPX protocol */
65 #define NP_AT   3               /* Appletalk protocol */
66 #define NP_MPLS_UC 4            /* MPLS unicast */
67 #define NP_MPLS_MC 5            /* MPLS multicast */
68 #define NUM_NP  6               /* Number of NPs. */
69
70 #define MPHDRLEN        6       /* multilink protocol header length */
71 #define MPHDRLEN_SSN    4       /* ditto with short sequence numbers */
72
73 /*
74  * An instance of /dev/ppp can be associated with either a ppp
75  * interface unit or a ppp channel.  In both cases, file->private_data
76  * points to one of these.
77  */
78 struct ppp_file {
79         enum {
80                 INTERFACE=1, CHANNEL
81         }               kind;
82         struct sk_buff_head xq;         /* pppd transmit queue */
83         struct sk_buff_head rq;         /* receive queue for pppd */
84         wait_queue_head_t rwait;        /* for poll on reading /dev/ppp */
85         atomic_t        refcnt;         /* # refs (incl /dev/ppp attached) */
86         int             hdrlen;         /* space to leave for headers */
87         int             index;          /* interface unit / channel number */
88         int             dead;           /* unit/channel has been shut down */
89 };
90
91 #define PF_TO_X(pf, X)          container_of(pf, X, file)
92
93 #define PF_TO_PPP(pf)           PF_TO_X(pf, struct ppp)
94 #define PF_TO_CHANNEL(pf)       PF_TO_X(pf, struct channel)
95
96 /*
97  * Data structure describing one ppp unit.
98  * A ppp unit corresponds to a ppp network interface device
99  * and represents a multilink bundle.
100  * It can have 0 or more ppp channels connected to it.
101  */
102 struct ppp {
103         struct ppp_file file;           /* stuff for read/write/poll 0 */
104         struct file     *owner;         /* file that owns this unit 48 */
105         struct list_head channels;      /* list of attached channels 4c */
106         int             n_channels;     /* how many channels are attached 54 */
107         spinlock_t      rlock;          /* lock for receive side 58 */
108         spinlock_t      wlock;          /* lock for transmit side 5c */
109         int             mru;            /* max receive unit 60 */
110         unsigned int    flags;          /* control bits 64 */
111         unsigned int    xstate;         /* transmit state bits 68 */
112         unsigned int    rstate;         /* receive state bits 6c */
113         int             debug;          /* debug flags 70 */
114         struct slcompress *vj;          /* state for VJ header compression */
115         enum NPmode     npmode[NUM_NP]; /* what to do with each net proto 78 */
116         struct sk_buff  *xmit_pending;  /* a packet ready to go out 88 */
117         struct compressor *xcomp;       /* transmit packet compressor 8c */
118         void            *xc_state;      /* its internal state 90 */
119         struct compressor *rcomp;       /* receive decompressor 94 */
120         void            *rc_state;      /* its internal state 98 */
121         unsigned long   last_xmit;      /* jiffies when last pkt sent 9c */
122         unsigned long   last_recv;      /* jiffies when last pkt rcvd a0 */
123         struct net_device *dev;         /* network interface device a4 */
124         int             closing;        /* is device closing down? a8 */
125 #ifdef CONFIG_PPP_MULTILINK
126         int             nxchan;         /* next channel to send something on */
127         u32             nxseq;          /* next sequence number to send */
128         int             mrru;           /* MP: max reconst. receive unit */
129         u32             nextseq;        /* MP: seq no of next packet */
130         u32             minseq;         /* MP: min of most recent seqnos */
131         struct sk_buff_head mrq;        /* MP: receive reconstruction queue */
132 #endif /* CONFIG_PPP_MULTILINK */
133 #ifdef CONFIG_PPP_FILTER
134         struct sock_filter *pass_filter;        /* filter for packets to pass */
135         struct sock_filter *active_filter;/* filter for pkts to reset idle */
136         unsigned pass_len, active_len;
137 #endif /* CONFIG_PPP_FILTER */
138         struct net      *ppp_net;       /* the net we belong to */
139 };
140
141 /*
142  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
143  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
144  * SC_MUST_COMP
145  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
146  * Bits in xstate: SC_COMP_RUN
147  */
148 #define SC_FLAG_BITS    (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
149                          |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
150                          |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
151
152 /*
153  * Private data structure for each channel.
154  * This includes the data structure used for multilink.
155  */
156 struct channel {
157         struct ppp_file file;           /* stuff for read/write/poll */
158         struct list_head list;          /* link in all/new_channels list */
159         struct ppp_channel *chan;       /* public channel data structure */
160         struct rw_semaphore chan_sem;   /* protects `chan' during chan ioctl */
161         spinlock_t      downl;          /* protects `chan', file.xq dequeue */
162         struct ppp      *ppp;           /* ppp unit we're connected to */
163         struct net      *chan_net;      /* the net channel belongs to */
164         struct list_head clist;         /* link in list of channels per unit */
165         rwlock_t        upl;            /* protects `ppp' */
166 #ifdef CONFIG_PPP_MULTILINK
167         u8              avail;          /* flag used in multilink stuff */
168         u8              had_frag;       /* >= 1 fragments have been sent */
169         u32             lastseq;        /* MP: last sequence # received */
170         int             speed;          /* speed of the corresponding ppp channel*/
171 #endif /* CONFIG_PPP_MULTILINK */
172 };
173
174 /*
175  * SMP locking issues:
176  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
177  * list and the ppp.n_channels field, you need to take both locks
178  * before you modify them.
179  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
180  * channel.downl.
181  */
182
183 static DEFINE_MUTEX(ppp_mutex);
184 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
185 static atomic_t channel_count = ATOMIC_INIT(0);
186
187 /* per-net private data for this module */
188 static int ppp_net_id __read_mostly;
189 struct ppp_net {
190         /* units to ppp mapping */
191         struct idr units_idr;
192
193         /*
194          * all_ppp_mutex protects the units_idr mapping.
195          * It also ensures that finding a ppp unit in the units_idr
196          * map and updating its file.refcnt field is atomic.
197          */
198         struct mutex all_ppp_mutex;
199
200         /* channels */
201         struct list_head all_channels;
202         struct list_head new_channels;
203         int last_channel_index;
204
205         /*
206          * all_channels_lock protects all_channels and
207          * last_channel_index, and the atomicity of find
208          * a channel and updating its file.refcnt field.
209          */
210         spinlock_t all_channels_lock;
211 };
212
213 /* Get the PPP protocol number from a skb */
214 #define PPP_PROTO(skb)  get_unaligned_be16((skb)->data)
215
216 /* We limit the length of ppp->file.rq to this (arbitrary) value */
217 #define PPP_MAX_RQLEN   32
218
219 /*
220  * Maximum number of multilink fragments queued up.
221  * This has to be large enough to cope with the maximum latency of
222  * the slowest channel relative to the others.  Strictly it should
223  * depend on the number of channels and their characteristics.
224  */
225 #define PPP_MP_MAX_QLEN 128
226
227 /* Multilink header bits. */
228 #define B       0x80            /* this fragment begins a packet */
229 #define E       0x40            /* this fragment ends a packet */
230
231 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
232 #define seq_before(a, b)        ((s32)((a) - (b)) < 0)
233 #define seq_after(a, b)         ((s32)((a) - (b)) > 0)
234
235 /* Prototypes. */
236 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
237                         struct file *file, unsigned int cmd, unsigned long arg);
238 static void ppp_xmit_process(struct ppp *ppp);
239 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
240 static void ppp_push(struct ppp *ppp);
241 static void ppp_channel_push(struct channel *pch);
242 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
243                               struct channel *pch);
244 static void ppp_receive_error(struct ppp *ppp);
245 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
246 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
247                                             struct sk_buff *skb);
248 #ifdef CONFIG_PPP_MULTILINK
249 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
250                                 struct channel *pch);
251 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
252 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
253 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
254 #endif /* CONFIG_PPP_MULTILINK */
255 static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
256 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
257 static void ppp_ccp_closed(struct ppp *ppp);
258 static struct compressor *find_compressor(int type);
259 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
260 static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
261 static void init_ppp_file(struct ppp_file *pf, int kind);
262 static void ppp_shutdown_interface(struct ppp *ppp);
263 static void ppp_destroy_interface(struct ppp *ppp);
264 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
265 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
266 static int ppp_connect_channel(struct channel *pch, int unit);
267 static int ppp_disconnect_channel(struct channel *pch);
268 static void ppp_destroy_channel(struct channel *pch);
269 static int unit_get(struct idr *p, void *ptr);
270 static int unit_set(struct idr *p, void *ptr, int n);
271 static void unit_put(struct idr *p, int n);
272 static void *unit_find(struct idr *p, int n);
273
274 static struct class *ppp_class;
275
276 /* per net-namespace data */
277 static inline struct ppp_net *ppp_pernet(struct net *net)
278 {
279         BUG_ON(!net);
280
281         return net_generic(net, ppp_net_id);
282 }
283
284 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
285 static inline int proto_to_npindex(int proto)
286 {
287         switch (proto) {
288         case PPP_IP:
289                 return NP_IP;
290         case PPP_IPV6:
291                 return NP_IPV6;
292         case PPP_IPX:
293                 return NP_IPX;
294         case PPP_AT:
295                 return NP_AT;
296         case PPP_MPLS_UC:
297                 return NP_MPLS_UC;
298         case PPP_MPLS_MC:
299                 return NP_MPLS_MC;
300         }
301         return -EINVAL;
302 }
303
304 /* Translates an NP index into a PPP protocol number */
305 static const int npindex_to_proto[NUM_NP] = {
306         PPP_IP,
307         PPP_IPV6,
308         PPP_IPX,
309         PPP_AT,
310         PPP_MPLS_UC,
311         PPP_MPLS_MC,
312 };
313
314 /* Translates an ethertype into an NP index */
315 static inline int ethertype_to_npindex(int ethertype)
316 {
317         switch (ethertype) {
318         case ETH_P_IP:
319                 return NP_IP;
320         case ETH_P_IPV6:
321                 return NP_IPV6;
322         case ETH_P_IPX:
323                 return NP_IPX;
324         case ETH_P_PPPTALK:
325         case ETH_P_ATALK:
326                 return NP_AT;
327         case ETH_P_MPLS_UC:
328                 return NP_MPLS_UC;
329         case ETH_P_MPLS_MC:
330                 return NP_MPLS_MC;
331         }
332         return -1;
333 }
334
335 /* Translates an NP index into an ethertype */
336 static const int npindex_to_ethertype[NUM_NP] = {
337         ETH_P_IP,
338         ETH_P_IPV6,
339         ETH_P_IPX,
340         ETH_P_PPPTALK,
341         ETH_P_MPLS_UC,
342         ETH_P_MPLS_MC,
343 };
344
345 /*
346  * Locking shorthand.
347  */
348 #define ppp_xmit_lock(ppp)      spin_lock_bh(&(ppp)->wlock)
349 #define ppp_xmit_unlock(ppp)    spin_unlock_bh(&(ppp)->wlock)
350 #define ppp_recv_lock(ppp)      spin_lock_bh(&(ppp)->rlock)
351 #define ppp_recv_unlock(ppp)    spin_unlock_bh(&(ppp)->rlock)
352 #define ppp_lock(ppp)           do { ppp_xmit_lock(ppp); \
353                                      ppp_recv_lock(ppp); } while (0)
354 #define ppp_unlock(ppp)         do { ppp_recv_unlock(ppp); \
355                                      ppp_xmit_unlock(ppp); } while (0)
356
357 /*
358  * /dev/ppp device routines.
359  * The /dev/ppp device is used by pppd to control the ppp unit.
360  * It supports the read, write, ioctl and poll functions.
361  * Open instances of /dev/ppp can be in one of three states:
362  * unattached, attached to a ppp unit, or attached to a ppp channel.
363  */
364 static int ppp_open(struct inode *inode, struct file *file)
365 {
366         /*
367          * This could (should?) be enforced by the permissions on /dev/ppp.
368          */
369         if (!capable(CAP_NET_ADMIN))
370                 return -EPERM;
371         return 0;
372 }
373
374 static int ppp_release(struct inode *unused, struct file *file)
375 {
376         struct ppp_file *pf = file->private_data;
377         struct ppp *ppp;
378
379         if (pf) {
380                 file->private_data = NULL;
381                 if (pf->kind == INTERFACE) {
382                         ppp = PF_TO_PPP(pf);
383                         if (file == ppp->owner)
384                                 ppp_shutdown_interface(ppp);
385                 }
386                 if (atomic_dec_and_test(&pf->refcnt)) {
387                         switch (pf->kind) {
388                         case INTERFACE:
389                                 ppp_destroy_interface(PF_TO_PPP(pf));
390                                 break;
391                         case CHANNEL:
392                                 ppp_destroy_channel(PF_TO_CHANNEL(pf));
393                                 break;
394                         }
395                 }
396         }
397         return 0;
398 }
399
400 static ssize_t ppp_read(struct file *file, char __user *buf,
401                         size_t count, loff_t *ppos)
402 {
403         struct ppp_file *pf = file->private_data;
404         DECLARE_WAITQUEUE(wait, current);
405         ssize_t ret;
406         struct sk_buff *skb = NULL;
407         struct iovec iov;
408
409         ret = count;
410
411         if (!pf)
412                 return -ENXIO;
413         add_wait_queue(&pf->rwait, &wait);
414         for (;;) {
415                 set_current_state(TASK_INTERRUPTIBLE);
416                 skb = skb_dequeue(&pf->rq);
417                 if (skb)
418                         break;
419                 ret = 0;
420                 if (pf->dead)
421                         break;
422                 if (pf->kind == INTERFACE) {
423                         /*
424                          * Return 0 (EOF) on an interface that has no
425                          * channels connected, unless it is looping
426                          * network traffic (demand mode).
427                          */
428                         struct ppp *ppp = PF_TO_PPP(pf);
429                         if (ppp->n_channels == 0 &&
430                             (ppp->flags & SC_LOOP_TRAFFIC) == 0)
431                                 break;
432                 }
433                 ret = -EAGAIN;
434                 if (file->f_flags & O_NONBLOCK)
435                         break;
436                 ret = -ERESTARTSYS;
437                 if (signal_pending(current))
438                         break;
439                 schedule();
440         }
441         set_current_state(TASK_RUNNING);
442         remove_wait_queue(&pf->rwait, &wait);
443
444         if (!skb)
445                 goto out;
446
447         ret = -EOVERFLOW;
448         if (skb->len > count)
449                 goto outf;
450         ret = -EFAULT;
451         iov.iov_base = buf;
452         iov.iov_len = count;
453         if (skb_copy_datagram_iovec(skb, 0, &iov, skb->len))
454                 goto outf;
455         ret = skb->len;
456
457  outf:
458         kfree_skb(skb);
459  out:
460         return ret;
461 }
462
463 static ssize_t ppp_write(struct file *file, const char __user *buf,
464                          size_t count, loff_t *ppos)
465 {
466         struct ppp_file *pf = file->private_data;
467         struct sk_buff *skb;
468         ssize_t ret;
469
470         if (!pf)
471                 return -ENXIO;
472         ret = -ENOMEM;
473         skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
474         if (!skb)
475                 goto out;
476         skb_reserve(skb, pf->hdrlen);
477         ret = -EFAULT;
478         if (copy_from_user(skb_put(skb, count), buf, count)) {
479                 kfree_skb(skb);
480                 goto out;
481         }
482
483         skb_queue_tail(&pf->xq, skb);
484
485         switch (pf->kind) {
486         case INTERFACE:
487                 ppp_xmit_process(PF_TO_PPP(pf));
488                 break;
489         case CHANNEL:
490                 ppp_channel_push(PF_TO_CHANNEL(pf));
491                 break;
492         }
493
494         ret = count;
495
496  out:
497         return ret;
498 }
499
500 /* No kernel lock - fine */
501 static unsigned int ppp_poll(struct file *file, poll_table *wait)
502 {
503         struct ppp_file *pf = file->private_data;
504         unsigned int mask;
505
506         if (!pf)
507                 return 0;
508         poll_wait(file, &pf->rwait, wait);
509         mask = POLLOUT | POLLWRNORM;
510         if (skb_peek(&pf->rq))
511                 mask |= POLLIN | POLLRDNORM;
512         if (pf->dead)
513                 mask |= POLLHUP;
514         else if (pf->kind == INTERFACE) {
515                 /* see comment in ppp_read */
516                 struct ppp *ppp = PF_TO_PPP(pf);
517                 if (ppp->n_channels == 0 &&
518                     (ppp->flags & SC_LOOP_TRAFFIC) == 0)
519                         mask |= POLLIN | POLLRDNORM;
520         }
521
522         return mask;
523 }
524
525 #ifdef CONFIG_PPP_FILTER
526 static int get_filter(void __user *arg, struct sock_filter **p)
527 {
528         struct sock_fprog uprog;
529         struct sock_filter *code = NULL;
530         int len, err;
531
532         if (copy_from_user(&uprog, arg, sizeof(uprog)))
533                 return -EFAULT;
534
535         if (!uprog.len) {
536                 *p = NULL;
537                 return 0;
538         }
539
540         len = uprog.len * sizeof(struct sock_filter);
541         code = memdup_user(uprog.filter, len);
542         if (IS_ERR(code))
543                 return PTR_ERR(code);
544
545         err = sk_chk_filter(code, uprog.len);
546         if (err) {
547                 kfree(code);
548                 return err;
549         }
550
551         *p = code;
552         return uprog.len;
553 }
554 #endif /* CONFIG_PPP_FILTER */
555
556 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
557 {
558         struct ppp_file *pf = file->private_data;
559         struct ppp *ppp;
560         int err = -EFAULT, val, val2, i;
561         struct ppp_idle idle;
562         struct npioctl npi;
563         int unit, cflags;
564         struct slcompress *vj;
565         void __user *argp = (void __user *)arg;
566         int __user *p = argp;
567
568         if (!pf)
569                 return ppp_unattached_ioctl(current->nsproxy->net_ns,
570                                         pf, file, cmd, arg);
571
572         if (cmd == PPPIOCDETACH) {
573                 /*
574                  * We have to be careful here... if the file descriptor
575                  * has been dup'd, we could have another process in the
576                  * middle of a poll using the same file *, so we had
577                  * better not free the interface data structures -
578                  * instead we fail the ioctl.  Even in this case, we
579                  * shut down the interface if we are the owner of it.
580                  * Actually, we should get rid of PPPIOCDETACH, userland
581                  * (i.e. pppd) could achieve the same effect by closing
582                  * this fd and reopening /dev/ppp.
583                  */
584                 err = -EINVAL;
585                 mutex_lock(&ppp_mutex);
586                 if (pf->kind == INTERFACE) {
587                         ppp = PF_TO_PPP(pf);
588                         if (file == ppp->owner)
589                                 ppp_shutdown_interface(ppp);
590                 }
591                 if (atomic_long_read(&file->f_count) <= 2) {
592                         ppp_release(NULL, file);
593                         err = 0;
594                 } else
595                         pr_warn("PPPIOCDETACH file->f_count=%ld\n",
596                                 atomic_long_read(&file->f_count));
597                 mutex_unlock(&ppp_mutex);
598                 return err;
599         }
600
601         if (pf->kind == CHANNEL) {
602                 struct channel *pch;
603                 struct ppp_channel *chan;
604
605                 mutex_lock(&ppp_mutex);
606                 pch = PF_TO_CHANNEL(pf);
607
608                 switch (cmd) {
609                 case PPPIOCCONNECT:
610                         if (get_user(unit, p))
611                                 break;
612                         err = ppp_connect_channel(pch, unit);
613                         break;
614
615                 case PPPIOCDISCONN:
616                         err = ppp_disconnect_channel(pch);
617                         break;
618
619                 default:
620                         down_read(&pch->chan_sem);
621                         chan = pch->chan;
622                         err = -ENOTTY;
623                         if (chan && chan->ops->ioctl)
624                                 err = chan->ops->ioctl(chan, cmd, arg);
625                         up_read(&pch->chan_sem);
626                 }
627                 mutex_unlock(&ppp_mutex);
628                 return err;
629         }
630
631         if (pf->kind != INTERFACE) {
632                 /* can't happen */
633                 pr_err("PPP: not interface or channel??\n");
634                 return -EINVAL;
635         }
636
637         mutex_lock(&ppp_mutex);
638         ppp = PF_TO_PPP(pf);
639         switch (cmd) {
640         case PPPIOCSMRU:
641                 if (get_user(val, p))
642                         break;
643                 ppp->mru = val;
644                 err = 0;
645                 break;
646
647         case PPPIOCSFLAGS:
648                 if (get_user(val, p))
649                         break;
650                 ppp_lock(ppp);
651                 cflags = ppp->flags & ~val;
652                 ppp->flags = val & SC_FLAG_BITS;
653                 ppp_unlock(ppp);
654                 if (cflags & SC_CCP_OPEN)
655                         ppp_ccp_closed(ppp);
656                 err = 0;
657                 break;
658
659         case PPPIOCGFLAGS:
660                 val = ppp->flags | ppp->xstate | ppp->rstate;
661                 if (put_user(val, p))
662                         break;
663                 err = 0;
664                 break;
665
666         case PPPIOCSCOMPRESS:
667                 err = ppp_set_compress(ppp, arg);
668                 break;
669
670         case PPPIOCGUNIT:
671                 if (put_user(ppp->file.index, p))
672                         break;
673                 err = 0;
674                 break;
675
676         case PPPIOCSDEBUG:
677                 if (get_user(val, p))
678                         break;
679                 ppp->debug = val;
680                 err = 0;
681                 break;
682
683         case PPPIOCGDEBUG:
684                 if (put_user(ppp->debug, p))
685                         break;
686                 err = 0;
687                 break;
688
689         case PPPIOCGIDLE:
690                 idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
691                 idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
692                 if (copy_to_user(argp, &idle, sizeof(idle)))
693                         break;
694                 err = 0;
695                 break;
696
697         case PPPIOCSMAXCID:
698                 if (get_user(val, p))
699                         break;
700                 val2 = 15;
701                 if ((val >> 16) != 0) {
702                         val2 = val >> 16;
703                         val &= 0xffff;
704                 }
705                 vj = slhc_init(val2+1, val+1);
706                 if (!vj) {
707                         netdev_err(ppp->dev,
708                                    "PPP: no memory (VJ compressor)\n");
709                         err = -ENOMEM;
710                         break;
711                 }
712                 ppp_lock(ppp);
713                 if (ppp->vj)
714                         slhc_free(ppp->vj);
715                 ppp->vj = vj;
716                 ppp_unlock(ppp);
717                 err = 0;
718                 break;
719
720         case PPPIOCGNPMODE:
721         case PPPIOCSNPMODE:
722                 if (copy_from_user(&npi, argp, sizeof(npi)))
723                         break;
724                 err = proto_to_npindex(npi.protocol);
725                 if (err < 0)
726                         break;
727                 i = err;
728                 if (cmd == PPPIOCGNPMODE) {
729                         err = -EFAULT;
730                         npi.mode = ppp->npmode[i];
731                         if (copy_to_user(argp, &npi, sizeof(npi)))
732                                 break;
733                 } else {
734                         ppp->npmode[i] = npi.mode;
735                         /* we may be able to transmit more packets now (??) */
736                         netif_wake_queue(ppp->dev);
737                 }
738                 err = 0;
739                 break;
740
741 #ifdef CONFIG_PPP_FILTER
742         case PPPIOCSPASS:
743         {
744                 struct sock_filter *code;
745                 err = get_filter(argp, &code);
746                 if (err >= 0) {
747                         ppp_lock(ppp);
748                         kfree(ppp->pass_filter);
749                         ppp->pass_filter = code;
750                         ppp->pass_len = err;
751                         ppp_unlock(ppp);
752                         err = 0;
753                 }
754                 break;
755         }
756         case PPPIOCSACTIVE:
757         {
758                 struct sock_filter *code;
759                 err = get_filter(argp, &code);
760                 if (err >= 0) {
761                         ppp_lock(ppp);
762                         kfree(ppp->active_filter);
763                         ppp->active_filter = code;
764                         ppp->active_len = err;
765                         ppp_unlock(ppp);
766                         err = 0;
767                 }
768                 break;
769         }
770 #endif /* CONFIG_PPP_FILTER */
771
772 #ifdef CONFIG_PPP_MULTILINK
773         case PPPIOCSMRRU:
774                 if (get_user(val, p))
775                         break;
776                 ppp_recv_lock(ppp);
777                 ppp->mrru = val;
778                 ppp_recv_unlock(ppp);
779                 err = 0;
780                 break;
781 #endif /* CONFIG_PPP_MULTILINK */
782
783         default:
784                 err = -ENOTTY;
785         }
786         mutex_unlock(&ppp_mutex);
787         return err;
788 }
789
790 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
791                         struct file *file, unsigned int cmd, unsigned long arg)
792 {
793         int unit, err = -EFAULT;
794         struct ppp *ppp;
795         struct channel *chan;
796         struct ppp_net *pn;
797         int __user *p = (int __user *)arg;
798
799         mutex_lock(&ppp_mutex);
800         switch (cmd) {
801         case PPPIOCNEWUNIT:
802                 /* Create a new ppp unit */
803                 if (get_user(unit, p))
804                         break;
805                 ppp = ppp_create_interface(net, unit, &err);
806                 if (!ppp)
807                         break;
808                 file->private_data = &ppp->file;
809                 ppp->owner = file;
810                 err = -EFAULT;
811                 if (put_user(ppp->file.index, p))
812                         break;
813                 err = 0;
814                 break;
815
816         case PPPIOCATTACH:
817                 /* Attach to an existing ppp unit */
818                 if (get_user(unit, p))
819                         break;
820                 err = -ENXIO;
821                 pn = ppp_pernet(net);
822                 mutex_lock(&pn->all_ppp_mutex);
823                 ppp = ppp_find_unit(pn, unit);
824                 if (ppp) {
825                         atomic_inc(&ppp->file.refcnt);
826                         file->private_data = &ppp->file;
827                         err = 0;
828                 }
829                 mutex_unlock(&pn->all_ppp_mutex);
830                 break;
831
832         case PPPIOCATTCHAN:
833                 if (get_user(unit, p))
834                         break;
835                 err = -ENXIO;
836                 pn = ppp_pernet(net);
837                 spin_lock_bh(&pn->all_channels_lock);
838                 chan = ppp_find_channel(pn, unit);
839                 if (chan) {
840                         atomic_inc(&chan->file.refcnt);
841                         file->private_data = &chan->file;
842                         err = 0;
843                 }
844                 spin_unlock_bh(&pn->all_channels_lock);
845                 break;
846
847         default:
848                 err = -ENOTTY;
849         }
850         mutex_unlock(&ppp_mutex);
851         return err;
852 }
853
854 static const struct file_operations ppp_device_fops = {
855         .owner          = THIS_MODULE,
856         .read           = ppp_read,
857         .write          = ppp_write,
858         .poll           = ppp_poll,
859         .unlocked_ioctl = ppp_ioctl,
860         .open           = ppp_open,
861         .release        = ppp_release,
862         .llseek         = noop_llseek,
863 };
864
865 static __net_init int ppp_init_net(struct net *net)
866 {
867         struct ppp_net *pn = net_generic(net, ppp_net_id);
868
869         idr_init(&pn->units_idr);
870         mutex_init(&pn->all_ppp_mutex);
871
872         INIT_LIST_HEAD(&pn->all_channels);
873         INIT_LIST_HEAD(&pn->new_channels);
874
875         spin_lock_init(&pn->all_channels_lock);
876
877         return 0;
878 }
879
880 static __net_exit void ppp_exit_net(struct net *net)
881 {
882         struct ppp_net *pn = net_generic(net, ppp_net_id);
883
884         idr_destroy(&pn->units_idr);
885 }
886
887 static struct pernet_operations ppp_net_ops = {
888         .init = ppp_init_net,
889         .exit = ppp_exit_net,
890         .id   = &ppp_net_id,
891         .size = sizeof(struct ppp_net),
892 };
893
894 #define PPP_MAJOR       108
895
896 /* Called at boot time if ppp is compiled into the kernel,
897    or at module load time (from init_module) if compiled as a module. */
898 static int __init ppp_init(void)
899 {
900         int err;
901
902         pr_info("PPP generic driver version " PPP_VERSION "\n");
903
904         err = register_pernet_device(&ppp_net_ops);
905         if (err) {
906                 pr_err("failed to register PPP pernet device (%d)\n", err);
907                 goto out;
908         }
909
910         err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
911         if (err) {
912                 pr_err("failed to register PPP device (%d)\n", err);
913                 goto out_net;
914         }
915
916         ppp_class = class_create(THIS_MODULE, "ppp");
917         if (IS_ERR(ppp_class)) {
918                 err = PTR_ERR(ppp_class);
919                 goto out_chrdev;
920         }
921
922         /* not a big deal if we fail here :-) */
923         device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
924
925         return 0;
926
927 out_chrdev:
928         unregister_chrdev(PPP_MAJOR, "ppp");
929 out_net:
930         unregister_pernet_device(&ppp_net_ops);
931 out:
932         return err;
933 }
934
935 /*
936  * Network interface unit routines.
937  */
938 static netdev_tx_t
939 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
940 {
941         struct ppp *ppp = netdev_priv(dev);
942         int npi, proto;
943         unsigned char *pp;
944
945         npi = ethertype_to_npindex(ntohs(skb->protocol));
946         if (npi < 0)
947                 goto outf;
948
949         /* Drop, accept or reject the packet */
950         switch (ppp->npmode[npi]) {
951         case NPMODE_PASS:
952                 break;
953         case NPMODE_QUEUE:
954                 /* it would be nice to have a way to tell the network
955                    system to queue this one up for later. */
956                 goto outf;
957         case NPMODE_DROP:
958         case NPMODE_ERROR:
959                 goto outf;
960         }
961
962         /* Put the 2-byte PPP protocol number on the front,
963            making sure there is room for the address and control fields. */
964         if (skb_cow_head(skb, PPP_HDRLEN))
965                 goto outf;
966
967         pp = skb_push(skb, 2);
968         proto = npindex_to_proto[npi];
969         put_unaligned_be16(proto, pp);
970
971         netif_stop_queue(dev);
972         skb_queue_tail(&ppp->file.xq, skb);
973         ppp_xmit_process(ppp);
974         return NETDEV_TX_OK;
975
976  outf:
977         kfree_skb(skb);
978         ++dev->stats.tx_dropped;
979         return NETDEV_TX_OK;
980 }
981
982 static int
983 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
984 {
985         struct ppp *ppp = netdev_priv(dev);
986         int err = -EFAULT;
987         void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
988         struct ppp_stats stats;
989         struct ppp_comp_stats cstats;
990         char *vers;
991
992         switch (cmd) {
993         case SIOCGPPPSTATS:
994                 ppp_get_stats(ppp, &stats);
995                 if (copy_to_user(addr, &stats, sizeof(stats)))
996                         break;
997                 err = 0;
998                 break;
999
1000         case SIOCGPPPCSTATS:
1001                 memset(&cstats, 0, sizeof(cstats));
1002                 if (ppp->xc_state)
1003                         ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1004                 if (ppp->rc_state)
1005                         ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1006                 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1007                         break;
1008                 err = 0;
1009                 break;
1010
1011         case SIOCGPPPVER:
1012                 vers = PPP_VERSION;
1013                 if (copy_to_user(addr, vers, strlen(vers) + 1))
1014                         break;
1015                 err = 0;
1016                 break;
1017
1018         default:
1019                 err = -EINVAL;
1020         }
1021
1022         return err;
1023 }
1024
1025 static const struct net_device_ops ppp_netdev_ops = {
1026         .ndo_start_xmit = ppp_start_xmit,
1027         .ndo_do_ioctl   = ppp_net_ioctl,
1028 };
1029
1030 static void ppp_setup(struct net_device *dev)
1031 {
1032         dev->netdev_ops = &ppp_netdev_ops;
1033         dev->hard_header_len = PPP_HDRLEN;
1034         dev->mtu = PPP_MTU;
1035         dev->addr_len = 0;
1036         dev->tx_queue_len = 3;
1037         dev->type = ARPHRD_PPP;
1038         dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1039         dev->features |= NETIF_F_NETNS_LOCAL;
1040         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1041 }
1042
1043 /*
1044  * Transmit-side routines.
1045  */
1046
1047 /*
1048  * Called to do any work queued up on the transmit side
1049  * that can now be done.
1050  */
1051 static void
1052 ppp_xmit_process(struct ppp *ppp)
1053 {
1054         struct sk_buff *skb;
1055
1056         ppp_xmit_lock(ppp);
1057         if (!ppp->closing) {
1058                 ppp_push(ppp);
1059                 while (!ppp->xmit_pending &&
1060                        (skb = skb_dequeue(&ppp->file.xq)))
1061                         ppp_send_frame(ppp, skb);
1062                 /* If there's no work left to do, tell the core net
1063                    code that we can accept some more. */
1064                 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1065                         netif_wake_queue(ppp->dev);
1066         }
1067         ppp_xmit_unlock(ppp);
1068 }
1069
1070 static inline struct sk_buff *
1071 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1072 {
1073         struct sk_buff *new_skb;
1074         int len;
1075         int new_skb_size = ppp->dev->mtu +
1076                 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1077         int compressor_skb_size = ppp->dev->mtu +
1078                 ppp->xcomp->comp_extra + PPP_HDRLEN;
1079         new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1080         if (!new_skb) {
1081                 if (net_ratelimit())
1082                         netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1083                 return NULL;
1084         }
1085         if (ppp->dev->hard_header_len > PPP_HDRLEN)
1086                 skb_reserve(new_skb,
1087                             ppp->dev->hard_header_len - PPP_HDRLEN);
1088
1089         /* compressor still expects A/C bytes in hdr */
1090         len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1091                                    new_skb->data, skb->len + 2,
1092                                    compressor_skb_size);
1093         if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1094                 kfree_skb(skb);
1095                 skb = new_skb;
1096                 skb_put(skb, len);
1097                 skb_pull(skb, 2);       /* pull off A/C bytes */
1098         } else if (len == 0) {
1099                 /* didn't compress, or CCP not up yet */
1100                 kfree_skb(new_skb);
1101                 new_skb = skb;
1102         } else {
1103                 /*
1104                  * (len < 0)
1105                  * MPPE requires that we do not send unencrypted
1106                  * frames.  The compressor will return -1 if we
1107                  * should drop the frame.  We cannot simply test
1108                  * the compress_proto because MPPE and MPPC share
1109                  * the same number.
1110                  */
1111                 if (net_ratelimit())
1112                         netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1113                 kfree_skb(skb);
1114                 kfree_skb(new_skb);
1115                 new_skb = NULL;
1116         }
1117         return new_skb;
1118 }
1119
1120 /*
1121  * Compress and send a frame.
1122  * The caller should have locked the xmit path,
1123  * and xmit_pending should be 0.
1124  */
1125 static void
1126 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1127 {
1128         int proto = PPP_PROTO(skb);
1129         struct sk_buff *new_skb;
1130         int len;
1131         unsigned char *cp;
1132
1133         if (proto < 0x8000) {
1134 #ifdef CONFIG_PPP_FILTER
1135                 /* check if we should pass this packet */
1136                 /* the filter instructions are constructed assuming
1137                    a four-byte PPP header on each packet */
1138                 *skb_push(skb, 2) = 1;
1139                 if (ppp->pass_filter &&
1140                     sk_run_filter(skb, ppp->pass_filter) == 0) {
1141                         if (ppp->debug & 1)
1142                                 netdev_printk(KERN_DEBUG, ppp->dev,
1143                                               "PPP: outbound frame "
1144                                               "not passed\n");
1145                         kfree_skb(skb);
1146                         return;
1147                 }
1148                 /* if this packet passes the active filter, record the time */
1149                 if (!(ppp->active_filter &&
1150                       sk_run_filter(skb, ppp->active_filter) == 0))
1151                         ppp->last_xmit = jiffies;
1152                 skb_pull(skb, 2);
1153 #else
1154                 /* for data packets, record the time */
1155                 ppp->last_xmit = jiffies;
1156 #endif /* CONFIG_PPP_FILTER */
1157         }
1158
1159         ++ppp->dev->stats.tx_packets;
1160         ppp->dev->stats.tx_bytes += skb->len - 2;
1161
1162         switch (proto) {
1163         case PPP_IP:
1164                 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1165                         break;
1166                 /* try to do VJ TCP header compression */
1167                 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1168                                     GFP_ATOMIC);
1169                 if (!new_skb) {
1170                         netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1171                         goto drop;
1172                 }
1173                 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1174                 cp = skb->data + 2;
1175                 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1176                                     new_skb->data + 2, &cp,
1177                                     !(ppp->flags & SC_NO_TCP_CCID));
1178                 if (cp == skb->data + 2) {
1179                         /* didn't compress */
1180                         kfree_skb(new_skb);
1181                 } else {
1182                         if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1183                                 proto = PPP_VJC_COMP;
1184                                 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1185                         } else {
1186                                 proto = PPP_VJC_UNCOMP;
1187                                 cp[0] = skb->data[2];
1188                         }
1189                         kfree_skb(skb);
1190                         skb = new_skb;
1191                         cp = skb_put(skb, len + 2);
1192                         cp[0] = 0;
1193                         cp[1] = proto;
1194                 }
1195                 break;
1196
1197         case PPP_CCP:
1198                 /* peek at outbound CCP frames */
1199                 ppp_ccp_peek(ppp, skb, 0);
1200                 break;
1201         }
1202
1203         /* try to do packet compression */
1204         if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1205             proto != PPP_LCP && proto != PPP_CCP) {
1206                 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1207                         if (net_ratelimit())
1208                                 netdev_err(ppp->dev,
1209                                            "ppp: compression required but "
1210                                            "down - pkt dropped.\n");
1211                         goto drop;
1212                 }
1213                 skb = pad_compress_skb(ppp, skb);
1214                 if (!skb)
1215                         goto drop;
1216         }
1217
1218         /*
1219          * If we are waiting for traffic (demand dialling),
1220          * queue it up for pppd to receive.
1221          */
1222         if (ppp->flags & SC_LOOP_TRAFFIC) {
1223                 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1224                         goto drop;
1225                 skb_queue_tail(&ppp->file.rq, skb);
1226                 wake_up_interruptible(&ppp->file.rwait);
1227                 return;
1228         }
1229
1230         ppp->xmit_pending = skb;
1231         ppp_push(ppp);
1232         return;
1233
1234  drop:
1235         kfree_skb(skb);
1236         ++ppp->dev->stats.tx_errors;
1237 }
1238
1239 /*
1240  * Try to send the frame in xmit_pending.
1241  * The caller should have the xmit path locked.
1242  */
1243 static void
1244 ppp_push(struct ppp *ppp)
1245 {
1246         struct list_head *list;
1247         struct channel *pch;
1248         struct sk_buff *skb = ppp->xmit_pending;
1249
1250         if (!skb)
1251                 return;
1252
1253         list = &ppp->channels;
1254         if (list_empty(list)) {
1255                 /* nowhere to send the packet, just drop it */
1256                 ppp->xmit_pending = NULL;
1257                 kfree_skb(skb);
1258                 return;
1259         }
1260
1261         if ((ppp->flags & SC_MULTILINK) == 0) {
1262                 /* not doing multilink: send it down the first channel */
1263                 list = list->next;
1264                 pch = list_entry(list, struct channel, clist);
1265
1266                 spin_lock_bh(&pch->downl);
1267                 if (pch->chan) {
1268                         if (pch->chan->ops->start_xmit(pch->chan, skb))
1269                                 ppp->xmit_pending = NULL;
1270                 } else {
1271                         /* channel got unregistered */
1272                         kfree_skb(skb);
1273                         ppp->xmit_pending = NULL;
1274                 }
1275                 spin_unlock_bh(&pch->downl);
1276                 return;
1277         }
1278
1279 #ifdef CONFIG_PPP_MULTILINK
1280         /* Multilink: fragment the packet over as many links
1281            as can take the packet at the moment. */
1282         if (!ppp_mp_explode(ppp, skb))
1283                 return;
1284 #endif /* CONFIG_PPP_MULTILINK */
1285
1286         ppp->xmit_pending = NULL;
1287         kfree_skb(skb);
1288 }
1289
1290 #ifdef CONFIG_PPP_MULTILINK
1291 static bool mp_protocol_compress __read_mostly = true;
1292 module_param(mp_protocol_compress, bool, S_IRUGO | S_IWUSR);
1293 MODULE_PARM_DESC(mp_protocol_compress,
1294                  "compress protocol id in multilink fragments");
1295
1296 /*
1297  * Divide a packet to be transmitted into fragments and
1298  * send them out the individual links.
1299  */
1300 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1301 {
1302         int len, totlen;
1303         int i, bits, hdrlen, mtu;
1304         int flen;
1305         int navail, nfree, nzero;
1306         int nbigger;
1307         int totspeed;
1308         int totfree;
1309         unsigned char *p, *q;
1310         struct list_head *list;
1311         struct channel *pch;
1312         struct sk_buff *frag;
1313         struct ppp_channel *chan;
1314
1315         totspeed = 0; /*total bitrate of the bundle*/
1316         nfree = 0; /* # channels which have no packet already queued */
1317         navail = 0; /* total # of usable channels (not deregistered) */
1318         nzero = 0; /* number of channels with zero speed associated*/
1319         totfree = 0; /*total # of channels available and
1320                                   *having no queued packets before
1321                                   *starting the fragmentation*/
1322
1323         hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1324         i = 0;
1325         list_for_each_entry(pch, &ppp->channels, clist) {
1326                 if (pch->chan) {
1327                         pch->avail = 1;
1328                         navail++;
1329                         pch->speed = pch->chan->speed;
1330                 } else {
1331                         pch->avail = 0;
1332                 }
1333                 if (pch->avail) {
1334                         if (skb_queue_empty(&pch->file.xq) ||
1335                                 !pch->had_frag) {
1336                                         if (pch->speed == 0)
1337                                                 nzero++;
1338                                         else
1339                                                 totspeed += pch->speed;
1340
1341                                         pch->avail = 2;
1342                                         ++nfree;
1343                                         ++totfree;
1344                                 }
1345                         if (!pch->had_frag && i < ppp->nxchan)
1346                                 ppp->nxchan = i;
1347                 }
1348                 ++i;
1349         }
1350         /*
1351          * Don't start sending this packet unless at least half of
1352          * the channels are free.  This gives much better TCP
1353          * performance if we have a lot of channels.
1354          */
1355         if (nfree == 0 || nfree < navail / 2)
1356                 return 0; /* can't take now, leave it in xmit_pending */
1357
1358         /* Do protocol field compression */
1359         p = skb->data;
1360         len = skb->len;
1361         if (*p == 0 && mp_protocol_compress) {
1362                 ++p;
1363                 --len;
1364         }
1365
1366         totlen = len;
1367         nbigger = len % nfree;
1368
1369         /* skip to the channel after the one we last used
1370            and start at that one */
1371         list = &ppp->channels;
1372         for (i = 0; i < ppp->nxchan; ++i) {
1373                 list = list->next;
1374                 if (list == &ppp->channels) {
1375                         i = 0;
1376                         break;
1377                 }
1378         }
1379
1380         /* create a fragment for each channel */
1381         bits = B;
1382         while (len > 0) {
1383                 list = list->next;
1384                 if (list == &ppp->channels) {
1385                         i = 0;
1386                         continue;
1387                 }
1388                 pch = list_entry(list, struct channel, clist);
1389                 ++i;
1390                 if (!pch->avail)
1391                         continue;
1392
1393                 /*
1394                  * Skip this channel if it has a fragment pending already and
1395                  * we haven't given a fragment to all of the free channels.
1396                  */
1397                 if (pch->avail == 1) {
1398                         if (nfree > 0)
1399                                 continue;
1400                 } else {
1401                         pch->avail = 1;
1402                 }
1403
1404                 /* check the channel's mtu and whether it is still attached. */
1405                 spin_lock_bh(&pch->downl);
1406                 if (pch->chan == NULL) {
1407                         /* can't use this channel, it's being deregistered */
1408                         if (pch->speed == 0)
1409                                 nzero--;
1410                         else
1411                                 totspeed -= pch->speed;
1412
1413                         spin_unlock_bh(&pch->downl);
1414                         pch->avail = 0;
1415                         totlen = len;
1416                         totfree--;
1417                         nfree--;
1418                         if (--navail == 0)
1419                                 break;
1420                         continue;
1421                 }
1422
1423                 /*
1424                 *if the channel speed is not set divide
1425                 *the packet evenly among the free channels;
1426                 *otherwise divide it according to the speed
1427                 *of the channel we are going to transmit on
1428                 */
1429                 flen = len;
1430                 if (nfree > 0) {
1431                         if (pch->speed == 0) {
1432                                 flen = len/nfree;
1433                                 if (nbigger > 0) {
1434                                         flen++;
1435                                         nbigger--;
1436                                 }
1437                         } else {
1438                                 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1439                                         ((totspeed*totfree)/pch->speed)) - hdrlen;
1440                                 if (nbigger > 0) {
1441                                         flen += ((totfree - nzero)*pch->speed)/totspeed;
1442                                         nbigger -= ((totfree - nzero)*pch->speed)/
1443                                                         totspeed;
1444                                 }
1445                         }
1446                         nfree--;
1447                 }
1448
1449                 /*
1450                  *check if we are on the last channel or
1451                  *we exceded the length of the data to
1452                  *fragment
1453                  */
1454                 if ((nfree <= 0) || (flen > len))
1455                         flen = len;
1456                 /*
1457                  *it is not worth to tx on slow channels:
1458                  *in that case from the resulting flen according to the
1459                  *above formula will be equal or less than zero.
1460                  *Skip the channel in this case
1461                  */
1462                 if (flen <= 0) {
1463                         pch->avail = 2;
1464                         spin_unlock_bh(&pch->downl);
1465                         continue;
1466                 }
1467
1468                 /*
1469                  * hdrlen includes the 2-byte PPP protocol field, but the
1470                  * MTU counts only the payload excluding the protocol field.
1471                  * (RFC1661 Section 2)
1472                  */
1473                 mtu = pch->chan->mtu - (hdrlen - 2);
1474                 if (mtu < 4)
1475                         mtu = 4;
1476                 if (flen > mtu)
1477                         flen = mtu;
1478                 if (flen == len)
1479                         bits |= E;
1480                 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1481                 if (!frag)
1482                         goto noskb;
1483                 q = skb_put(frag, flen + hdrlen);
1484
1485                 /* make the MP header */
1486                 put_unaligned_be16(PPP_MP, q);
1487                 if (ppp->flags & SC_MP_XSHORTSEQ) {
1488                         q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1489                         q[3] = ppp->nxseq;
1490                 } else {
1491                         q[2] = bits;
1492                         q[3] = ppp->nxseq >> 16;
1493                         q[4] = ppp->nxseq >> 8;
1494                         q[5] = ppp->nxseq;
1495                 }
1496
1497                 memcpy(q + hdrlen, p, flen);
1498
1499                 /* try to send it down the channel */
1500                 chan = pch->chan;
1501                 if (!skb_queue_empty(&pch->file.xq) ||
1502                         !chan->ops->start_xmit(chan, frag))
1503                         skb_queue_tail(&pch->file.xq, frag);
1504                 pch->had_frag = 1;
1505                 p += flen;
1506                 len -= flen;
1507                 ++ppp->nxseq;
1508                 bits = 0;
1509                 spin_unlock_bh(&pch->downl);
1510         }
1511         ppp->nxchan = i;
1512
1513         return 1;
1514
1515  noskb:
1516         spin_unlock_bh(&pch->downl);
1517         if (ppp->debug & 1)
1518                 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1519         ++ppp->dev->stats.tx_errors;
1520         ++ppp->nxseq;
1521         return 1;       /* abandon the frame */
1522 }
1523 #endif /* CONFIG_PPP_MULTILINK */
1524
1525 /*
1526  * Try to send data out on a channel.
1527  */
1528 static void
1529 ppp_channel_push(struct channel *pch)
1530 {
1531         struct sk_buff *skb;
1532         struct ppp *ppp;
1533
1534         spin_lock_bh(&pch->downl);
1535         if (pch->chan) {
1536                 while (!skb_queue_empty(&pch->file.xq)) {
1537                         skb = skb_dequeue(&pch->file.xq);
1538                         if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1539                                 /* put the packet back and try again later */
1540                                 skb_queue_head(&pch->file.xq, skb);
1541                                 break;
1542                         }
1543                 }
1544         } else {
1545                 /* channel got deregistered */
1546                 skb_queue_purge(&pch->file.xq);
1547         }
1548         spin_unlock_bh(&pch->downl);
1549         /* see if there is anything from the attached unit to be sent */
1550         if (skb_queue_empty(&pch->file.xq)) {
1551                 read_lock_bh(&pch->upl);
1552                 ppp = pch->ppp;
1553                 if (ppp)
1554                         ppp_xmit_process(ppp);
1555                 read_unlock_bh(&pch->upl);
1556         }
1557 }
1558
1559 /*
1560  * Receive-side routines.
1561  */
1562
1563 struct ppp_mp_skb_parm {
1564         u32             sequence;
1565         u8              BEbits;
1566 };
1567 #define PPP_MP_CB(skb)  ((struct ppp_mp_skb_parm *)((skb)->cb))
1568
1569 static inline void
1570 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1571 {
1572         ppp_recv_lock(ppp);
1573         if (!ppp->closing)
1574                 ppp_receive_frame(ppp, skb, pch);
1575         else
1576                 kfree_skb(skb);
1577         ppp_recv_unlock(ppp);
1578 }
1579
1580 void
1581 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1582 {
1583         struct channel *pch = chan->ppp;
1584         int proto;
1585
1586         if (!pch) {
1587                 kfree_skb(skb);
1588                 return;
1589         }
1590
1591         read_lock_bh(&pch->upl);
1592         if (!pskb_may_pull(skb, 2)) {
1593                 kfree_skb(skb);
1594                 if (pch->ppp) {
1595                         ++pch->ppp->dev->stats.rx_length_errors;
1596                         ppp_receive_error(pch->ppp);
1597                 }
1598                 goto done;
1599         }
1600
1601         proto = PPP_PROTO(skb);
1602         if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1603                 /* put it on the channel queue */
1604                 skb_queue_tail(&pch->file.rq, skb);
1605                 /* drop old frames if queue too long */
1606                 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
1607                        (skb = skb_dequeue(&pch->file.rq)))
1608                         kfree_skb(skb);
1609                 wake_up_interruptible(&pch->file.rwait);
1610         } else {
1611                 ppp_do_recv(pch->ppp, skb, pch);
1612         }
1613
1614 done:
1615         read_unlock_bh(&pch->upl);
1616 }
1617
1618 /* Put a 0-length skb in the receive queue as an error indication */
1619 void
1620 ppp_input_error(struct ppp_channel *chan, int code)
1621 {
1622         struct channel *pch = chan->ppp;
1623         struct sk_buff *skb;
1624
1625         if (!pch)
1626                 return;
1627
1628         read_lock_bh(&pch->upl);
1629         if (pch->ppp) {
1630                 skb = alloc_skb(0, GFP_ATOMIC);
1631                 if (skb) {
1632                         skb->len = 0;           /* probably unnecessary */
1633                         skb->cb[0] = code;
1634                         ppp_do_recv(pch->ppp, skb, pch);
1635                 }
1636         }
1637         read_unlock_bh(&pch->upl);
1638 }
1639
1640 /*
1641  * We come in here to process a received frame.
1642  * The receive side of the ppp unit is locked.
1643  */
1644 static void
1645 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1646 {
1647         /* note: a 0-length skb is used as an error indication */
1648         if (skb->len > 0) {
1649 #ifdef CONFIG_PPP_MULTILINK
1650                 /* XXX do channel-level decompression here */
1651                 if (PPP_PROTO(skb) == PPP_MP)
1652                         ppp_receive_mp_frame(ppp, skb, pch);
1653                 else
1654 #endif /* CONFIG_PPP_MULTILINK */
1655                         ppp_receive_nonmp_frame(ppp, skb);
1656         } else {
1657                 kfree_skb(skb);
1658                 ppp_receive_error(ppp);
1659         }
1660 }
1661
1662 static void
1663 ppp_receive_error(struct ppp *ppp)
1664 {
1665         ++ppp->dev->stats.rx_errors;
1666         if (ppp->vj)
1667                 slhc_toss(ppp->vj);
1668 }
1669
1670 static void
1671 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1672 {
1673         struct sk_buff *ns;
1674         int proto, len, npi;
1675
1676         /*
1677          * Decompress the frame, if compressed.
1678          * Note that some decompressors need to see uncompressed frames
1679          * that come in as well as compressed frames.
1680          */
1681         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
1682             (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1683                 skb = ppp_decompress_frame(ppp, skb);
1684
1685         if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1686                 goto err;
1687
1688         proto = PPP_PROTO(skb);
1689         switch (proto) {
1690         case PPP_VJC_COMP:
1691                 /* decompress VJ compressed packets */
1692                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1693                         goto err;
1694
1695                 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1696                         /* copy to a new sk_buff with more tailroom */
1697                         ns = dev_alloc_skb(skb->len + 128);
1698                         if (!ns) {
1699                                 netdev_err(ppp->dev, "PPP: no memory "
1700                                            "(VJ decomp)\n");
1701                                 goto err;
1702                         }
1703                         skb_reserve(ns, 2);
1704                         skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1705                         kfree_skb(skb);
1706                         skb = ns;
1707                 }
1708                 else
1709                         skb->ip_summed = CHECKSUM_NONE;
1710
1711                 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1712                 if (len <= 0) {
1713                         netdev_printk(KERN_DEBUG, ppp->dev,
1714                                       "PPP: VJ decompression error\n");
1715                         goto err;
1716                 }
1717                 len += 2;
1718                 if (len > skb->len)
1719                         skb_put(skb, len - skb->len);
1720                 else if (len < skb->len)
1721                         skb_trim(skb, len);
1722                 proto = PPP_IP;
1723                 break;
1724
1725         case PPP_VJC_UNCOMP:
1726                 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1727                         goto err;
1728
1729                 /* Until we fix the decompressor need to make sure
1730                  * data portion is linear.
1731                  */
1732                 if (!pskb_may_pull(skb, skb->len))
1733                         goto err;
1734
1735                 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1736                         netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
1737                         goto err;
1738                 }
1739                 proto = PPP_IP;
1740                 break;
1741
1742         case PPP_CCP:
1743                 ppp_ccp_peek(ppp, skb, 1);
1744                 break;
1745         }
1746
1747         ++ppp->dev->stats.rx_packets;
1748         ppp->dev->stats.rx_bytes += skb->len - 2;
1749
1750         npi = proto_to_npindex(proto);
1751         if (npi < 0) {
1752                 /* control or unknown frame - pass it to pppd */
1753                 skb_queue_tail(&ppp->file.rq, skb);
1754                 /* limit queue length by dropping old frames */
1755                 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
1756                        (skb = skb_dequeue(&ppp->file.rq)))
1757                         kfree_skb(skb);
1758                 /* wake up any process polling or blocking on read */
1759                 wake_up_interruptible(&ppp->file.rwait);
1760
1761         } else {
1762                 /* network protocol frame - give it to the kernel */
1763
1764 #ifdef CONFIG_PPP_FILTER
1765                 /* check if the packet passes the pass and active filters */
1766                 /* the filter instructions are constructed assuming
1767                    a four-byte PPP header on each packet */
1768                 if (ppp->pass_filter || ppp->active_filter) {
1769                         if (skb_cloned(skb) &&
1770                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1771                                 goto err;
1772
1773                         *skb_push(skb, 2) = 0;
1774                         if (ppp->pass_filter &&
1775                             sk_run_filter(skb, ppp->pass_filter) == 0) {
1776                                 if (ppp->debug & 1)
1777                                         netdev_printk(KERN_DEBUG, ppp->dev,
1778                                                       "PPP: inbound frame "
1779                                                       "not passed\n");
1780                                 kfree_skb(skb);
1781                                 return;
1782                         }
1783                         if (!(ppp->active_filter &&
1784                               sk_run_filter(skb, ppp->active_filter) == 0))
1785                                 ppp->last_recv = jiffies;
1786                         __skb_pull(skb, 2);
1787                 } else
1788 #endif /* CONFIG_PPP_FILTER */
1789                         ppp->last_recv = jiffies;
1790
1791                 if ((ppp->dev->flags & IFF_UP) == 0 ||
1792                     ppp->npmode[npi] != NPMODE_PASS) {
1793                         kfree_skb(skb);
1794                 } else {
1795                         /* chop off protocol */
1796                         skb_pull_rcsum(skb, 2);
1797                         skb->dev = ppp->dev;
1798                         skb->protocol = htons(npindex_to_ethertype[npi]);
1799                         skb_reset_mac_header(skb);
1800                         netif_rx(skb);
1801                 }
1802         }
1803         return;
1804
1805  err:
1806         kfree_skb(skb);
1807         ppp_receive_error(ppp);
1808 }
1809
1810 static struct sk_buff *
1811 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1812 {
1813         int proto = PPP_PROTO(skb);
1814         struct sk_buff *ns;
1815         int len;
1816
1817         /* Until we fix all the decompressor's need to make sure
1818          * data portion is linear.
1819          */
1820         if (!pskb_may_pull(skb, skb->len))
1821                 goto err;
1822
1823         if (proto == PPP_COMP) {
1824                 int obuff_size;
1825
1826                 switch(ppp->rcomp->compress_proto) {
1827                 case CI_MPPE:
1828                         obuff_size = ppp->mru + PPP_HDRLEN + 1;
1829                         break;
1830                 default:
1831                         obuff_size = ppp->mru + PPP_HDRLEN;
1832                         break;
1833                 }
1834
1835                 ns = dev_alloc_skb(obuff_size);
1836                 if (!ns) {
1837                         netdev_err(ppp->dev, "ppp_decompress_frame: "
1838                                    "no memory\n");
1839                         goto err;
1840                 }
1841                 /* the decompressor still expects the A/C bytes in the hdr */
1842                 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1843                                 skb->len + 2, ns->data, obuff_size);
1844                 if (len < 0) {
1845                         /* Pass the compressed frame to pppd as an
1846                            error indication. */
1847                         if (len == DECOMP_FATALERROR)
1848                                 ppp->rstate |= SC_DC_FERROR;
1849                         kfree_skb(ns);
1850                         goto err;
1851                 }
1852
1853                 kfree_skb(skb);
1854                 skb = ns;
1855                 skb_put(skb, len);
1856                 skb_pull(skb, 2);       /* pull off the A/C bytes */
1857
1858         } else {
1859                 /* Uncompressed frame - pass to decompressor so it
1860                    can update its dictionary if necessary. */
1861                 if (ppp->rcomp->incomp)
1862                         ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1863                                            skb->len + 2);
1864         }
1865
1866         return skb;
1867
1868  err:
1869         ppp->rstate |= SC_DC_ERROR;
1870         ppp_receive_error(ppp);
1871         return skb;
1872 }
1873
1874 #ifdef CONFIG_PPP_MULTILINK
1875 /*
1876  * Receive a multilink frame.
1877  * We put it on the reconstruction queue and then pull off
1878  * as many completed frames as we can.
1879  */
1880 static void
1881 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1882 {
1883         u32 mask, seq;
1884         struct channel *ch;
1885         int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1886
1887         if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1888                 goto err;               /* no good, throw it away */
1889
1890         /* Decode sequence number and begin/end bits */
1891         if (ppp->flags & SC_MP_SHORTSEQ) {
1892                 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1893                 mask = 0xfff;
1894         } else {
1895                 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1896                 mask = 0xffffff;
1897         }
1898         PPP_MP_CB(skb)->BEbits = skb->data[2];
1899         skb_pull(skb, mphdrlen);        /* pull off PPP and MP headers */
1900
1901         /*
1902          * Do protocol ID decompression on the first fragment of each packet.
1903          */
1904         if ((PPP_MP_CB(skb)->BEbits & B) && (skb->data[0] & 1))
1905                 *skb_push(skb, 1) = 0;
1906
1907         /*
1908          * Expand sequence number to 32 bits, making it as close
1909          * as possible to ppp->minseq.
1910          */
1911         seq |= ppp->minseq & ~mask;
1912         if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1913                 seq += mask + 1;
1914         else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1915                 seq -= mask + 1;        /* should never happen */
1916         PPP_MP_CB(skb)->sequence = seq;
1917         pch->lastseq = seq;
1918
1919         /*
1920          * If this packet comes before the next one we were expecting,
1921          * drop it.
1922          */
1923         if (seq_before(seq, ppp->nextseq)) {
1924                 kfree_skb(skb);
1925                 ++ppp->dev->stats.rx_dropped;
1926                 ppp_receive_error(ppp);
1927                 return;
1928         }
1929
1930         /*
1931          * Reevaluate minseq, the minimum over all channels of the
1932          * last sequence number received on each channel.  Because of
1933          * the increasing sequence number rule, we know that any fragment
1934          * before `minseq' which hasn't arrived is never going to arrive.
1935          * The list of channels can't change because we have the receive
1936          * side of the ppp unit locked.
1937          */
1938         list_for_each_entry(ch, &ppp->channels, clist) {
1939                 if (seq_before(ch->lastseq, seq))
1940                         seq = ch->lastseq;
1941         }
1942         if (seq_before(ppp->minseq, seq))
1943                 ppp->minseq = seq;
1944
1945         /* Put the fragment on the reconstruction queue */
1946         ppp_mp_insert(ppp, skb);
1947
1948         /* If the queue is getting long, don't wait any longer for packets
1949            before the start of the queue. */
1950         if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1951                 struct sk_buff *mskb = skb_peek(&ppp->mrq);
1952                 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
1953                         ppp->minseq = PPP_MP_CB(mskb)->sequence;
1954         }
1955
1956         /* Pull completed packets off the queue and receive them. */
1957         while ((skb = ppp_mp_reconstruct(ppp))) {
1958                 if (pskb_may_pull(skb, 2))
1959                         ppp_receive_nonmp_frame(ppp, skb);
1960                 else {
1961                         ++ppp->dev->stats.rx_length_errors;
1962                         kfree_skb(skb);
1963                         ppp_receive_error(ppp);
1964                 }
1965         }
1966
1967         return;
1968
1969  err:
1970         kfree_skb(skb);
1971         ppp_receive_error(ppp);
1972 }
1973
1974 /*
1975  * Insert a fragment on the MP reconstruction queue.
1976  * The queue is ordered by increasing sequence number.
1977  */
1978 static void
1979 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1980 {
1981         struct sk_buff *p;
1982         struct sk_buff_head *list = &ppp->mrq;
1983         u32 seq = PPP_MP_CB(skb)->sequence;
1984
1985         /* N.B. we don't need to lock the list lock because we have the
1986            ppp unit receive-side lock. */
1987         skb_queue_walk(list, p) {
1988                 if (seq_before(seq, PPP_MP_CB(p)->sequence))
1989                         break;
1990         }
1991         __skb_queue_before(list, p, skb);
1992 }
1993
1994 /*
1995  * Reconstruct a packet from the MP fragment queue.
1996  * We go through increasing sequence numbers until we find a
1997  * complete packet, or we get to the sequence number for a fragment
1998  * which hasn't arrived but might still do so.
1999  */
2000 static struct sk_buff *
2001 ppp_mp_reconstruct(struct ppp *ppp)
2002 {
2003         u32 seq = ppp->nextseq;
2004         u32 minseq = ppp->minseq;
2005         struct sk_buff_head *list = &ppp->mrq;
2006         struct sk_buff *p, *tmp;
2007         struct sk_buff *head, *tail;
2008         struct sk_buff *skb = NULL;
2009         int lost = 0, len = 0;
2010
2011         if (ppp->mrru == 0)     /* do nothing until mrru is set */
2012                 return NULL;
2013         head = list->next;
2014         tail = NULL;
2015         skb_queue_walk_safe(list, p, tmp) {
2016         again:
2017                 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2018                         /* this can't happen, anyway ignore the skb */
2019                         netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2020                                    "seq %u < %u\n",
2021                                    PPP_MP_CB(p)->sequence, seq);
2022                         __skb_unlink(p, list);
2023                         kfree_skb(p);
2024                         continue;
2025                 }
2026                 if (PPP_MP_CB(p)->sequence != seq) {
2027                         /* Fragment `seq' is missing.  If it is after
2028                            minseq, it might arrive later, so stop here. */
2029                         if (seq_after(seq, minseq))
2030                                 break;
2031                         /* Fragment `seq' is lost, keep going. */
2032                         lost = 1;
2033                         seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2034                                 minseq + 1: PPP_MP_CB(p)->sequence;
2035                         goto again;
2036                 }
2037
2038                 /*
2039                  * At this point we know that all the fragments from
2040                  * ppp->nextseq to seq are either present or lost.
2041                  * Also, there are no complete packets in the queue
2042                  * that have no missing fragments and end before this
2043                  * fragment.
2044                  */
2045
2046                 /* B bit set indicates this fragment starts a packet */
2047                 if (PPP_MP_CB(p)->BEbits & B) {
2048                         head = p;
2049                         lost = 0;
2050                         len = 0;
2051                 }
2052
2053                 len += p->len;
2054
2055                 /* Got a complete packet yet? */
2056                 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2057                     (PPP_MP_CB(head)->BEbits & B)) {
2058                         if (len > ppp->mrru + 2) {
2059                                 ++ppp->dev->stats.rx_length_errors;
2060                                 netdev_printk(KERN_DEBUG, ppp->dev,
2061                                               "PPP: reconstructed packet"
2062                                               " is too long (%d)\n", len);
2063                         } else {
2064                                 tail = p;
2065                                 break;
2066                         }
2067                         ppp->nextseq = seq + 1;
2068                 }
2069
2070                 /*
2071                  * If this is the ending fragment of a packet,
2072                  * and we haven't found a complete valid packet yet,
2073                  * we can discard up to and including this fragment.
2074                  */
2075                 if (PPP_MP_CB(p)->BEbits & E) {
2076                         struct sk_buff *tmp2;
2077
2078                         skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2079                                 __skb_unlink(p, list);
2080                                 kfree_skb(p);
2081                         }
2082                         head = skb_peek(list);
2083                         if (!head)
2084                                 break;
2085                 }
2086                 ++seq;
2087         }
2088
2089         /* If we have a complete packet, copy it all into one skb. */
2090         if (tail != NULL) {
2091                 /* If we have discarded any fragments,
2092                    signal a receive error. */
2093                 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2094                         if (ppp->debug & 1)
2095                                 netdev_printk(KERN_DEBUG, ppp->dev,
2096                                               "  missed pkts %u..%u\n",
2097                                               ppp->nextseq,
2098                                               PPP_MP_CB(head)->sequence-1);
2099                         ++ppp->dev->stats.rx_dropped;
2100                         ppp_receive_error(ppp);
2101                 }
2102
2103                 skb = head;
2104                 if (head != tail) {
2105                         struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2106                         p = skb_queue_next(list, head);
2107                         __skb_unlink(skb, list);
2108                         skb_queue_walk_from_safe(list, p, tmp) {
2109                                 __skb_unlink(p, list);
2110                                 *fragpp = p;
2111                                 p->next = NULL;
2112                                 fragpp = &p->next;
2113
2114                                 skb->len += p->len;
2115                                 skb->data_len += p->len;
2116                                 skb->truesize += p->len;
2117
2118                                 if (p == tail)
2119                                         break;
2120                         }
2121                 } else {
2122                         __skb_unlink(skb, list);
2123                 }
2124
2125                 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2126         }
2127
2128         return skb;
2129 }
2130 #endif /* CONFIG_PPP_MULTILINK */
2131
2132 /*
2133  * Channel interface.
2134  */
2135
2136 /* Create a new, unattached ppp channel. */
2137 int ppp_register_channel(struct ppp_channel *chan)
2138 {
2139         return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2140 }
2141
2142 /* Create a new, unattached ppp channel for specified net. */
2143 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2144 {
2145         struct channel *pch;
2146         struct ppp_net *pn;
2147
2148         pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2149         if (!pch)
2150                 return -ENOMEM;
2151
2152         pn = ppp_pernet(net);
2153
2154         pch->ppp = NULL;
2155         pch->chan = chan;
2156         pch->chan_net = net;
2157         chan->ppp = pch;
2158         init_ppp_file(&pch->file, CHANNEL);
2159         pch->file.hdrlen = chan->hdrlen;
2160 #ifdef CONFIG_PPP_MULTILINK
2161         pch->lastseq = -1;
2162 #endif /* CONFIG_PPP_MULTILINK */
2163         init_rwsem(&pch->chan_sem);
2164         spin_lock_init(&pch->downl);
2165         rwlock_init(&pch->upl);
2166
2167         spin_lock_bh(&pn->all_channels_lock);
2168         pch->file.index = ++pn->last_channel_index;
2169         list_add(&pch->list, &pn->new_channels);
2170         atomic_inc(&channel_count);
2171         spin_unlock_bh(&pn->all_channels_lock);
2172
2173         return 0;
2174 }
2175
2176 /*
2177  * Return the index of a channel.
2178  */
2179 int ppp_channel_index(struct ppp_channel *chan)
2180 {
2181         struct channel *pch = chan->ppp;
2182
2183         if (pch)
2184                 return pch->file.index;
2185         return -1;
2186 }
2187
2188 /*
2189  * Return the PPP unit number to which a channel is connected.
2190  */
2191 int ppp_unit_number(struct ppp_channel *chan)
2192 {
2193         struct channel *pch = chan->ppp;
2194         int unit = -1;
2195
2196         if (pch) {
2197                 read_lock_bh(&pch->upl);
2198                 if (pch->ppp)
2199                         unit = pch->ppp->file.index;
2200                 read_unlock_bh(&pch->upl);
2201         }
2202         return unit;
2203 }
2204
2205 /*
2206  * Return the PPP device interface name of a channel.
2207  */
2208 char *ppp_dev_name(struct ppp_channel *chan)
2209 {
2210         struct channel *pch = chan->ppp;
2211         char *name = NULL;
2212
2213         if (pch) {
2214                 read_lock_bh(&pch->upl);
2215                 if (pch->ppp && pch->ppp->dev)
2216                         name = pch->ppp->dev->name;
2217                 read_unlock_bh(&pch->upl);
2218         }
2219         return name;
2220 }
2221
2222
2223 /*
2224  * Disconnect a channel from the generic layer.
2225  * This must be called in process context.
2226  */
2227 void
2228 ppp_unregister_channel(struct ppp_channel *chan)
2229 {
2230         struct channel *pch = chan->ppp;
2231         struct ppp_net *pn;
2232
2233         if (!pch)
2234                 return;         /* should never happen */
2235
2236         chan->ppp = NULL;
2237
2238         /*
2239          * This ensures that we have returned from any calls into the
2240          * the channel's start_xmit or ioctl routine before we proceed.
2241          */
2242         down_write(&pch->chan_sem);
2243         spin_lock_bh(&pch->downl);
2244         pch->chan = NULL;
2245         spin_unlock_bh(&pch->downl);
2246         up_write(&pch->chan_sem);
2247         ppp_disconnect_channel(pch);
2248
2249         pn = ppp_pernet(pch->chan_net);
2250         spin_lock_bh(&pn->all_channels_lock);
2251         list_del(&pch->list);
2252         spin_unlock_bh(&pn->all_channels_lock);
2253
2254         pch->file.dead = 1;
2255         wake_up_interruptible(&pch->file.rwait);
2256         if (atomic_dec_and_test(&pch->file.refcnt))
2257                 ppp_destroy_channel(pch);
2258 }
2259
2260 /*
2261  * Callback from a channel when it can accept more to transmit.
2262  * This should be called at BH/softirq level, not interrupt level.
2263  */
2264 void
2265 ppp_output_wakeup(struct ppp_channel *chan)
2266 {
2267         struct channel *pch = chan->ppp;
2268
2269         if (!pch)
2270                 return;
2271         ppp_channel_push(pch);
2272 }
2273
2274 /*
2275  * Compression control.
2276  */
2277
2278 /* Process the PPPIOCSCOMPRESS ioctl. */
2279 static int
2280 ppp_set_compress(struct ppp *ppp, unsigned long arg)
2281 {
2282         int err;
2283         struct compressor *cp, *ocomp;
2284         struct ppp_option_data data;
2285         void *state, *ostate;
2286         unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2287
2288         err = -EFAULT;
2289         if (copy_from_user(&data, (void __user *) arg, sizeof(data)) ||
2290             (data.length <= CCP_MAX_OPTION_LENGTH &&
2291              copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2292                 goto out;
2293         err = -EINVAL;
2294         if (data.length > CCP_MAX_OPTION_LENGTH ||
2295             ccp_option[1] < 2 || ccp_option[1] > data.length)
2296                 goto out;
2297
2298         cp = try_then_request_module(
2299                 find_compressor(ccp_option[0]),
2300                 "ppp-compress-%d", ccp_option[0]);
2301         if (!cp)
2302                 goto out;
2303
2304         err = -ENOBUFS;
2305         if (data.transmit) {
2306                 state = cp->comp_alloc(ccp_option, data.length);
2307                 if (state) {
2308                         ppp_xmit_lock(ppp);
2309                         ppp->xstate &= ~SC_COMP_RUN;
2310                         ocomp = ppp->xcomp;
2311                         ostate = ppp->xc_state;
2312                         ppp->xcomp = cp;
2313                         ppp->xc_state = state;
2314                         ppp_xmit_unlock(ppp);
2315                         if (ostate) {
2316                                 ocomp->comp_free(ostate);
2317                                 module_put(ocomp->owner);
2318                         }
2319                         err = 0;
2320                 } else
2321                         module_put(cp->owner);
2322
2323         } else {
2324                 state = cp->decomp_alloc(ccp_option, data.length);
2325                 if (state) {
2326                         ppp_recv_lock(ppp);
2327                         ppp->rstate &= ~SC_DECOMP_RUN;
2328                         ocomp = ppp->rcomp;
2329                         ostate = ppp->rc_state;
2330                         ppp->rcomp = cp;
2331                         ppp->rc_state = state;
2332                         ppp_recv_unlock(ppp);
2333                         if (ostate) {
2334                                 ocomp->decomp_free(ostate);
2335                                 module_put(ocomp->owner);
2336                         }
2337                         err = 0;
2338                 } else
2339                         module_put(cp->owner);
2340         }
2341
2342  out:
2343         return err;
2344 }
2345
2346 /*
2347  * Look at a CCP packet and update our state accordingly.
2348  * We assume the caller has the xmit or recv path locked.
2349  */
2350 static void
2351 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2352 {
2353         unsigned char *dp;
2354         int len;
2355
2356         if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2357                 return; /* no header */
2358         dp = skb->data + 2;
2359
2360         switch (CCP_CODE(dp)) {
2361         case CCP_CONFREQ:
2362
2363                 /* A ConfReq starts negotiation of compression
2364                  * in one direction of transmission,
2365                  * and hence brings it down...but which way?
2366                  *
2367                  * Remember:
2368                  * A ConfReq indicates what the sender would like to receive
2369                  */
2370                 if(inbound)
2371                         /* He is proposing what I should send */
2372                         ppp->xstate &= ~SC_COMP_RUN;
2373                 else
2374                         /* I am proposing to what he should send */
2375                         ppp->rstate &= ~SC_DECOMP_RUN;
2376
2377                 break;
2378
2379         case CCP_TERMREQ:
2380         case CCP_TERMACK:
2381                 /*
2382                  * CCP is going down, both directions of transmission
2383                  */
2384                 ppp->rstate &= ~SC_DECOMP_RUN;
2385                 ppp->xstate &= ~SC_COMP_RUN;
2386                 break;
2387
2388         case CCP_CONFACK:
2389                 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2390                         break;
2391                 len = CCP_LENGTH(dp);
2392                 if (!pskb_may_pull(skb, len + 2))
2393                         return;         /* too short */
2394                 dp += CCP_HDRLEN;
2395                 len -= CCP_HDRLEN;
2396                 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2397                         break;
2398                 if (inbound) {
2399                         /* we will start receiving compressed packets */
2400                         if (!ppp->rc_state)
2401                                 break;
2402                         if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2403                                         ppp->file.index, 0, ppp->mru, ppp->debug)) {
2404                                 ppp->rstate |= SC_DECOMP_RUN;
2405                                 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2406                         }
2407                 } else {
2408                         /* we will soon start sending compressed packets */
2409                         if (!ppp->xc_state)
2410                                 break;
2411                         if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2412                                         ppp->file.index, 0, ppp->debug))
2413                                 ppp->xstate |= SC_COMP_RUN;
2414                 }
2415                 break;
2416
2417         case CCP_RESETACK:
2418                 /* reset the [de]compressor */
2419                 if ((ppp->flags & SC_CCP_UP) == 0)
2420                         break;
2421                 if (inbound) {
2422                         if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2423                                 ppp->rcomp->decomp_reset(ppp->rc_state);
2424                                 ppp->rstate &= ~SC_DC_ERROR;
2425                         }
2426                 } else {
2427                         if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2428                                 ppp->xcomp->comp_reset(ppp->xc_state);
2429                 }
2430                 break;
2431         }
2432 }
2433
2434 /* Free up compression resources. */
2435 static void
2436 ppp_ccp_closed(struct ppp *ppp)
2437 {
2438         void *xstate, *rstate;
2439         struct compressor *xcomp, *rcomp;
2440
2441         ppp_lock(ppp);
2442         ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2443         ppp->xstate = 0;
2444         xcomp = ppp->xcomp;
2445         xstate = ppp->xc_state;
2446         ppp->xc_state = NULL;
2447         ppp->rstate = 0;
2448         rcomp = ppp->rcomp;
2449         rstate = ppp->rc_state;
2450         ppp->rc_state = NULL;
2451         ppp_unlock(ppp);
2452
2453         if (xstate) {
2454                 xcomp->comp_free(xstate);
2455                 module_put(xcomp->owner);
2456         }
2457         if (rstate) {
2458                 rcomp->decomp_free(rstate);
2459                 module_put(rcomp->owner);
2460         }
2461 }
2462
2463 /* List of compressors. */
2464 static LIST_HEAD(compressor_list);
2465 static DEFINE_SPINLOCK(compressor_list_lock);
2466
2467 struct compressor_entry {
2468         struct list_head list;
2469         struct compressor *comp;
2470 };
2471
2472 static struct compressor_entry *
2473 find_comp_entry(int proto)
2474 {
2475         struct compressor_entry *ce;
2476
2477         list_for_each_entry(ce, &compressor_list, list) {
2478                 if (ce->comp->compress_proto == proto)
2479                         return ce;
2480         }
2481         return NULL;
2482 }
2483
2484 /* Register a compressor */
2485 int
2486 ppp_register_compressor(struct compressor *cp)
2487 {
2488         struct compressor_entry *ce;
2489         int ret;
2490         spin_lock(&compressor_list_lock);
2491         ret = -EEXIST;
2492         if (find_comp_entry(cp->compress_proto))
2493                 goto out;
2494         ret = -ENOMEM;
2495         ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2496         if (!ce)
2497                 goto out;
2498         ret = 0;
2499         ce->comp = cp;
2500         list_add(&ce->list, &compressor_list);
2501  out:
2502         spin_unlock(&compressor_list_lock);
2503         return ret;
2504 }
2505
2506 /* Unregister a compressor */
2507 void
2508 ppp_unregister_compressor(struct compressor *cp)
2509 {
2510         struct compressor_entry *ce;
2511
2512         spin_lock(&compressor_list_lock);
2513         ce = find_comp_entry(cp->compress_proto);
2514         if (ce && ce->comp == cp) {
2515                 list_del(&ce->list);
2516                 kfree(ce);
2517         }
2518         spin_unlock(&compressor_list_lock);
2519 }
2520
2521 /* Find a compressor. */
2522 static struct compressor *
2523 find_compressor(int type)
2524 {
2525         struct compressor_entry *ce;
2526         struct compressor *cp = NULL;
2527
2528         spin_lock(&compressor_list_lock);
2529         ce = find_comp_entry(type);
2530         if (ce) {
2531                 cp = ce->comp;
2532                 if (!try_module_get(cp->owner))
2533                         cp = NULL;
2534         }
2535         spin_unlock(&compressor_list_lock);
2536         return cp;
2537 }
2538
2539 /*
2540  * Miscelleneous stuff.
2541  */
2542
2543 static void
2544 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2545 {
2546         struct slcompress *vj = ppp->vj;
2547
2548         memset(st, 0, sizeof(*st));
2549         st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2550         st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2551         st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2552         st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2553         st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2554         st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2555         if (!vj)
2556                 return;
2557         st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2558         st->vj.vjs_compressed = vj->sls_o_compressed;
2559         st->vj.vjs_searches = vj->sls_o_searches;
2560         st->vj.vjs_misses = vj->sls_o_misses;
2561         st->vj.vjs_errorin = vj->sls_i_error;
2562         st->vj.vjs_tossed = vj->sls_i_tossed;
2563         st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2564         st->vj.vjs_compressedin = vj->sls_i_compressed;
2565 }
2566
2567 /*
2568  * Stuff for handling the lists of ppp units and channels
2569  * and for initialization.
2570  */
2571
2572 /*
2573  * Create a new ppp interface unit.  Fails if it can't allocate memory
2574  * or if there is already a unit with the requested number.
2575  * unit == -1 means allocate a new number.
2576  */
2577 static struct ppp *
2578 ppp_create_interface(struct net *net, int unit, int *retp)
2579 {
2580         struct ppp *ppp;
2581         struct ppp_net *pn;
2582         struct net_device *dev = NULL;
2583         int ret = -ENOMEM;
2584         int i;
2585
2586         dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2587         if (!dev)
2588                 goto out1;
2589
2590         pn = ppp_pernet(net);
2591
2592         ppp = netdev_priv(dev);
2593         ppp->dev = dev;
2594         ppp->mru = PPP_MRU;
2595         init_ppp_file(&ppp->file, INTERFACE);
2596         ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
2597         for (i = 0; i < NUM_NP; ++i)
2598                 ppp->npmode[i] = NPMODE_PASS;
2599         INIT_LIST_HEAD(&ppp->channels);
2600         spin_lock_init(&ppp->rlock);
2601         spin_lock_init(&ppp->wlock);
2602 #ifdef CONFIG_PPP_MULTILINK
2603         ppp->minseq = -1;
2604         skb_queue_head_init(&ppp->mrq);
2605 #endif /* CONFIG_PPP_MULTILINK */
2606
2607         /*
2608          * drum roll: don't forget to set
2609          * the net device is belong to
2610          */
2611         dev_net_set(dev, net);
2612
2613         mutex_lock(&pn->all_ppp_mutex);
2614
2615         if (unit < 0) {
2616                 unit = unit_get(&pn->units_idr, ppp);
2617                 if (unit < 0) {
2618                         ret = unit;
2619                         goto out2;
2620                 }
2621         } else {
2622                 ret = -EEXIST;
2623                 if (unit_find(&pn->units_idr, unit))
2624                         goto out2; /* unit already exists */
2625                 /*
2626                  * if caller need a specified unit number
2627                  * lets try to satisfy him, otherwise --
2628                  * he should better ask us for new unit number
2629                  *
2630                  * NOTE: yes I know that returning EEXIST it's not
2631                  * fair but at least pppd will ask us to allocate
2632                  * new unit in this case so user is happy :)
2633                  */
2634                 unit = unit_set(&pn->units_idr, ppp, unit);
2635                 if (unit < 0)
2636                         goto out2;
2637         }
2638
2639         /* Initialize the new ppp unit */
2640         ppp->file.index = unit;
2641         sprintf(dev->name, "ppp%d", unit);
2642
2643         ret = register_netdev(dev);
2644         if (ret != 0) {
2645                 unit_put(&pn->units_idr, unit);
2646                 netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n",
2647                            dev->name, ret);
2648                 goto out2;
2649         }
2650
2651         ppp->ppp_net = net;
2652
2653         atomic_inc(&ppp_unit_count);
2654         mutex_unlock(&pn->all_ppp_mutex);
2655
2656         *retp = 0;
2657         return ppp;
2658
2659 out2:
2660         mutex_unlock(&pn->all_ppp_mutex);
2661         free_netdev(dev);
2662 out1:
2663         *retp = ret;
2664         return NULL;
2665 }
2666
2667 /*
2668  * Initialize a ppp_file structure.
2669  */
2670 static void
2671 init_ppp_file(struct ppp_file *pf, int kind)
2672 {
2673         pf->kind = kind;
2674         skb_queue_head_init(&pf->xq);
2675         skb_queue_head_init(&pf->rq);
2676         atomic_set(&pf->refcnt, 1);
2677         init_waitqueue_head(&pf->rwait);
2678 }
2679
2680 /*
2681  * Take down a ppp interface unit - called when the owning file
2682  * (the one that created the unit) is closed or detached.
2683  */
2684 static void ppp_shutdown_interface(struct ppp *ppp)
2685 {
2686         struct ppp_net *pn;
2687
2688         pn = ppp_pernet(ppp->ppp_net);
2689         mutex_lock(&pn->all_ppp_mutex);
2690
2691         /* This will call dev_close() for us. */
2692         ppp_lock(ppp);
2693         if (!ppp->closing) {
2694                 ppp->closing = 1;
2695                 ppp_unlock(ppp);
2696                 unregister_netdev(ppp->dev);
2697                 unit_put(&pn->units_idr, ppp->file.index);
2698         } else
2699                 ppp_unlock(ppp);
2700
2701         ppp->file.dead = 1;
2702         ppp->owner = NULL;
2703         wake_up_interruptible(&ppp->file.rwait);
2704
2705         mutex_unlock(&pn->all_ppp_mutex);
2706 }
2707
2708 /*
2709  * Free the memory used by a ppp unit.  This is only called once
2710  * there are no channels connected to the unit and no file structs
2711  * that reference the unit.
2712  */
2713 static void ppp_destroy_interface(struct ppp *ppp)
2714 {
2715         atomic_dec(&ppp_unit_count);
2716
2717         if (!ppp->file.dead || ppp->n_channels) {
2718                 /* "can't happen" */
2719                 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
2720                            "but dead=%d n_channels=%d !\n",
2721                            ppp, ppp->file.dead, ppp->n_channels);
2722                 return;
2723         }
2724
2725         ppp_ccp_closed(ppp);
2726         if (ppp->vj) {
2727                 slhc_free(ppp->vj);
2728                 ppp->vj = NULL;
2729         }
2730         skb_queue_purge(&ppp->file.xq);
2731         skb_queue_purge(&ppp->file.rq);
2732 #ifdef CONFIG_PPP_MULTILINK
2733         skb_queue_purge(&ppp->mrq);
2734 #endif /* CONFIG_PPP_MULTILINK */
2735 #ifdef CONFIG_PPP_FILTER
2736         kfree(ppp->pass_filter);
2737         ppp->pass_filter = NULL;
2738         kfree(ppp->active_filter);
2739         ppp->active_filter = NULL;
2740 #endif /* CONFIG_PPP_FILTER */
2741
2742         kfree_skb(ppp->xmit_pending);
2743
2744         free_netdev(ppp->dev);
2745 }
2746
2747 /*
2748  * Locate an existing ppp unit.
2749  * The caller should have locked the all_ppp_mutex.
2750  */
2751 static struct ppp *
2752 ppp_find_unit(struct ppp_net *pn, int unit)
2753 {
2754         return unit_find(&pn->units_idr, unit);
2755 }
2756
2757 /*
2758  * Locate an existing ppp channel.
2759  * The caller should have locked the all_channels_lock.
2760  * First we look in the new_channels list, then in the
2761  * all_channels list.  If found in the new_channels list,
2762  * we move it to the all_channels list.  This is for speed
2763  * when we have a lot of channels in use.
2764  */
2765 static struct channel *
2766 ppp_find_channel(struct ppp_net *pn, int unit)
2767 {
2768         struct channel *pch;
2769
2770         list_for_each_entry(pch, &pn->new_channels, list) {
2771                 if (pch->file.index == unit) {
2772                         list_move(&pch->list, &pn->all_channels);
2773                         return pch;
2774                 }
2775         }
2776
2777         list_for_each_entry(pch, &pn->all_channels, list) {
2778                 if (pch->file.index == unit)
2779                         return pch;
2780         }
2781
2782         return NULL;
2783 }
2784
2785 /*
2786  * Connect a PPP channel to a PPP interface unit.
2787  */
2788 static int
2789 ppp_connect_channel(struct channel *pch, int unit)
2790 {
2791         struct ppp *ppp;
2792         struct ppp_net *pn;
2793         int ret = -ENXIO;
2794         int hdrlen;
2795
2796         pn = ppp_pernet(pch->chan_net);
2797
2798         mutex_lock(&pn->all_ppp_mutex);
2799         ppp = ppp_find_unit(pn, unit);
2800         if (!ppp)
2801                 goto out;
2802         write_lock_bh(&pch->upl);
2803         ret = -EINVAL;
2804         if (pch->ppp)
2805                 goto outl;
2806
2807         ppp_lock(ppp);
2808         if (pch->file.hdrlen > ppp->file.hdrlen)
2809                 ppp->file.hdrlen = pch->file.hdrlen;
2810         hdrlen = pch->file.hdrlen + 2;  /* for protocol bytes */
2811         if (hdrlen > ppp->dev->hard_header_len)
2812                 ppp->dev->hard_header_len = hdrlen;
2813         list_add_tail(&pch->clist, &ppp->channels);
2814         ++ppp->n_channels;
2815         pch->ppp = ppp;
2816         atomic_inc(&ppp->file.refcnt);
2817         ppp_unlock(ppp);
2818         ret = 0;
2819
2820  outl:
2821         write_unlock_bh(&pch->upl);
2822  out:
2823         mutex_unlock(&pn->all_ppp_mutex);
2824         return ret;
2825 }
2826
2827 /*
2828  * Disconnect a channel from its ppp unit.
2829  */
2830 static int
2831 ppp_disconnect_channel(struct channel *pch)
2832 {
2833         struct ppp *ppp;
2834         int err = -EINVAL;
2835
2836         write_lock_bh(&pch->upl);
2837         ppp = pch->ppp;
2838         pch->ppp = NULL;
2839         write_unlock_bh(&pch->upl);
2840         if (ppp) {
2841                 /* remove it from the ppp unit's list */
2842                 ppp_lock(ppp);
2843                 list_del(&pch->clist);
2844                 if (--ppp->n_channels == 0)
2845                         wake_up_interruptible(&ppp->file.rwait);
2846                 ppp_unlock(ppp);
2847                 if (atomic_dec_and_test(&ppp->file.refcnt))
2848                         ppp_destroy_interface(ppp);
2849                 err = 0;
2850         }
2851         return err;
2852 }
2853
2854 /*
2855  * Free up the resources used by a ppp channel.
2856  */
2857 static void ppp_destroy_channel(struct channel *pch)
2858 {
2859         atomic_dec(&channel_count);
2860
2861         if (!pch->file.dead) {
2862                 /* "can't happen" */
2863                 pr_err("ppp: destroying undead channel %p !\n", pch);
2864                 return;
2865         }
2866         skb_queue_purge(&pch->file.xq);
2867         skb_queue_purge(&pch->file.rq);
2868         kfree(pch);
2869 }
2870
2871 static void __exit ppp_cleanup(void)
2872 {
2873         /* should never happen */
2874         if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2875                 pr_err("PPP: removing module but units remain!\n");
2876         unregister_chrdev(PPP_MAJOR, "ppp");
2877         device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2878         class_destroy(ppp_class);
2879         unregister_pernet_device(&ppp_net_ops);
2880 }
2881
2882 /*
2883  * Units handling. Caller must protect concurrent access
2884  * by holding all_ppp_mutex
2885  */
2886
2887 static int __unit_alloc(struct idr *p, void *ptr, int n)
2888 {
2889         int unit, err;
2890
2891 again:
2892         if (!idr_pre_get(p, GFP_KERNEL)) {
2893                 pr_err("PPP: No free memory for idr\n");
2894                 return -ENOMEM;
2895         }
2896
2897         err = idr_get_new_above(p, ptr, n, &unit);
2898         if (err < 0) {
2899                 if (err == -EAGAIN)
2900                         goto again;
2901                 return err;
2902         }
2903
2904         return unit;
2905 }
2906
2907 /* associate pointer with specified number */
2908 static int unit_set(struct idr *p, void *ptr, int n)
2909 {
2910         int unit;
2911
2912         unit = __unit_alloc(p, ptr, n);
2913         if (unit < 0)
2914                 return unit;
2915         else if (unit != n) {
2916                 idr_remove(p, unit);
2917                 return -EINVAL;
2918         }
2919
2920         return unit;
2921 }
2922
2923 /* get new free unit number and associate pointer with it */
2924 static int unit_get(struct idr *p, void *ptr)
2925 {
2926         return __unit_alloc(p, ptr, 0);
2927 }
2928
2929 /* put unit number back to a pool */
2930 static void unit_put(struct idr *p, int n)
2931 {
2932         idr_remove(p, n);
2933 }
2934
2935 /* get pointer associated with the number */
2936 static void *unit_find(struct idr *p, int n)
2937 {
2938         return idr_find(p, n);
2939 }
2940
2941 /* Module/initialization stuff */
2942
2943 module_init(ppp_init);
2944 module_exit(ppp_cleanup);
2945
2946 EXPORT_SYMBOL(ppp_register_net_channel);
2947 EXPORT_SYMBOL(ppp_register_channel);
2948 EXPORT_SYMBOL(ppp_unregister_channel);
2949 EXPORT_SYMBOL(ppp_channel_index);
2950 EXPORT_SYMBOL(ppp_unit_number);
2951 EXPORT_SYMBOL(ppp_dev_name);
2952 EXPORT_SYMBOL(ppp_input);
2953 EXPORT_SYMBOL(ppp_input_error);
2954 EXPORT_SYMBOL(ppp_output_wakeup);
2955 EXPORT_SYMBOL(ppp_register_compressor);
2956 EXPORT_SYMBOL(ppp_unregister_compressor);
2957 MODULE_LICENSE("GPL");
2958 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
2959 MODULE_ALIAS("devname:ppp");