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