[PPP] pppoe: Fix skb_unshare_check call position
[linux-2.6.git] / drivers / net / pppoe.c
1 /** -*- linux-c -*- ***********************************************************
2  * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
3  *
4  * PPPoX --- Generic PPP encapsulation socket family
5  * PPPoE --- PPP over Ethernet (RFC 2516)
6  *
7  *
8  * Version:     0.7.0
9  *
10  * 070228 :     Fix to allow multiple sessions with same remote MAC and same
11  *              session id by including the local device ifindex in the
12  *              tuple identifying a session. This also ensures packets can't
13  *              be injected into a session from interfaces other than the one
14  *              specified by userspace. Florian Zumbiehl <florz@florz.de>
15  *              (Oh, BTW, this one is YYMMDD, in case you were wondering ...)
16  * 220102 :     Fix module use count on failure in pppoe_create, pppox_sk -acme
17  * 030700 :     Fixed connect logic to allow for disconnect.
18  * 270700 :     Fixed potential SMP problems; we must protect against
19  *              simultaneous invocation of ppp_input
20  *              and ppp_unregister_channel.
21  * 040800 :     Respect reference count mechanisms on net-devices.
22  * 200800 :     fix kfree(skb) in pppoe_rcv (acme)
23  *              Module reference count is decremented in the right spot now,
24  *              guards against sock_put not actually freeing the sk
25  *              in pppoe_release.
26  * 051000 :     Initialization cleanup.
27  * 111100 :     Fix recvmsg.
28  * 050101 :     Fix PADT procesing.
29  * 140501 :     Use pppoe_rcv_core to handle all backlog. (Alexey)
30  * 170701 :     Do not lock_sock with rwlock held. (DaveM)
31  *              Ignore discovery frames if user has socket
32  *              locked. (DaveM)
33  *              Ignore return value of dev_queue_xmit in __pppoe_xmit
34  *              or else we may kfree an SKB twice. (DaveM)
35  * 190701 :     When doing copies of skb's in __pppoe_xmit, always delete
36  *              the original skb that was passed in on success, never on
37  *              failure.  Delete the copy of the skb on failure to avoid
38  *              a memory leak.
39  * 081001 :     Misc. cleanup (licence string, non-blocking, prevent
40  *              reference of device on close).
41  * 121301 :     New ppp channels interface; cannot unregister a channel
42  *              from interrupts.  Thus, we mark the socket as a ZOMBIE
43  *              and do the unregistration later.
44  * 081002 :     seq_file support for proc stuff -acme
45  * 111602 :     Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
46  *              as version 0.7.  Spacing cleanup.
47  * Author:      Michal Ostrowski <mostrows@speakeasy.net>
48  * Contributors:
49  *              Arnaldo Carvalho de Melo <acme@conectiva.com.br>
50  *              David S. Miller (davem@redhat.com)
51  *
52  * License:
53  *              This program is free software; you can redistribute it and/or
54  *              modify it under the terms of the GNU General Public License
55  *              as published by the Free Software Foundation; either version
56  *              2 of the License, or (at your option) any later version.
57  *
58  */
59
60 #include <linux/string.h>
61 #include <linux/module.h>
62 #include <linux/kernel.h>
63 #include <linux/slab.h>
64 #include <linux/errno.h>
65 #include <linux/netdevice.h>
66 #include <linux/net.h>
67 #include <linux/inetdevice.h>
68 #include <linux/etherdevice.h>
69 #include <linux/skbuff.h>
70 #include <linux/init.h>
71 #include <linux/if_ether.h>
72 #include <linux/if_pppox.h>
73 #include <linux/ppp_channel.h>
74 #include <linux/ppp_defs.h>
75 #include <linux/if_ppp.h>
76 #include <linux/notifier.h>
77 #include <linux/file.h>
78 #include <linux/proc_fs.h>
79 #include <linux/seq_file.h>
80
81 #include <net/sock.h>
82
83 #include <asm/uaccess.h>
84
85 #define PPPOE_HASH_BITS 4
86 #define PPPOE_HASH_SIZE (1<<PPPOE_HASH_BITS)
87
88 static struct ppp_channel_ops pppoe_chan_ops;
89
90 static int pppoe_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
91 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb);
92 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
93
94 static const struct proto_ops pppoe_ops;
95 static DEFINE_RWLOCK(pppoe_hash_lock);
96
97 static struct ppp_channel_ops pppoe_chan_ops;
98
99 static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
100 {
101         return (a->sid == b->sid &&
102                 (memcmp(a->remote, b->remote, ETH_ALEN) == 0));
103 }
104
105 static inline int cmp_addr(struct pppoe_addr *a, unsigned long sid, char *addr)
106 {
107         return (a->sid == sid &&
108                 (memcmp(a->remote,addr,ETH_ALEN) == 0));
109 }
110
111 #if 8%PPPOE_HASH_BITS
112 #error 8 must be a multiple of PPPOE_HASH_BITS
113 #endif
114
115 static int hash_item(unsigned int sid, unsigned char *addr)
116 {
117         unsigned char hash = 0;
118         unsigned int i;
119
120         for (i = 0 ; i < ETH_ALEN ; i++) {
121                 hash ^= addr[i];
122         }
123         for (i = 0 ; i < sizeof(sid_t)*8 ; i += 8 ){
124                 hash ^= sid>>i;
125         }
126         for (i = 8 ; (i>>=1) >= PPPOE_HASH_BITS ; ) {
127                 hash ^= hash>>i;
128         }
129
130         return hash & ( PPPOE_HASH_SIZE - 1 );
131 }
132
133 /* zeroed because its in .bss */
134 static struct pppox_sock *item_hash_table[PPPOE_HASH_SIZE];
135
136 /**********************************************************************
137  *
138  *  Set/get/delete/rehash items  (internal versions)
139  *
140  **********************************************************************/
141 static struct pppox_sock *__get_item(unsigned long sid, unsigned char *addr, int ifindex)
142 {
143         int hash = hash_item(sid, addr);
144         struct pppox_sock *ret;
145
146         ret = item_hash_table[hash];
147
148         while (ret && !(cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex))
149                 ret = ret->next;
150
151         return ret;
152 }
153
154 static int __set_item(struct pppox_sock *po)
155 {
156         int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
157         struct pppox_sock *ret;
158
159         ret = item_hash_table[hash];
160         while (ret) {
161                 if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) && ret->pppoe_ifindex == po->pppoe_ifindex)
162                         return -EALREADY;
163
164                 ret = ret->next;
165         }
166
167         po->next = item_hash_table[hash];
168         item_hash_table[hash] = po;
169
170         return 0;
171 }
172
173 static struct pppox_sock *__delete_item(unsigned long sid, char *addr, int ifindex)
174 {
175         int hash = hash_item(sid, addr);
176         struct pppox_sock *ret, **src;
177
178         ret = item_hash_table[hash];
179         src = &item_hash_table[hash];
180
181         while (ret) {
182                 if (cmp_addr(&ret->pppoe_pa, sid, addr) && ret->pppoe_ifindex == ifindex) {
183                         *src = ret->next;
184                         break;
185                 }
186
187                 src = &ret->next;
188                 ret = ret->next;
189         }
190
191         return ret;
192 }
193
194 /**********************************************************************
195  *
196  *  Set/get/delete/rehash items
197  *
198  **********************************************************************/
199 static inline struct pppox_sock *get_item(unsigned long sid,
200                                          unsigned char *addr, int ifindex)
201 {
202         struct pppox_sock *po;
203
204         read_lock_bh(&pppoe_hash_lock);
205         po = __get_item(sid, addr, ifindex);
206         if (po)
207                 sock_hold(sk_pppox(po));
208         read_unlock_bh(&pppoe_hash_lock);
209
210         return po;
211 }
212
213 static inline struct pppox_sock *get_item_by_addr(struct sockaddr_pppox *sp)
214 {
215         struct net_device *dev;
216         int ifindex;
217
218         dev = dev_get_by_name(sp->sa_addr.pppoe.dev);
219         if(!dev)
220                 return NULL;
221         ifindex = dev->ifindex;
222         dev_put(dev);
223         return get_item(sp->sa_addr.pppoe.sid, sp->sa_addr.pppoe.remote, ifindex);
224 }
225
226 static inline struct pppox_sock *delete_item(unsigned long sid, char *addr, int ifindex)
227 {
228         struct pppox_sock *ret;
229
230         write_lock_bh(&pppoe_hash_lock);
231         ret = __delete_item(sid, addr, ifindex);
232         write_unlock_bh(&pppoe_hash_lock);
233
234         return ret;
235 }
236
237
238
239 /***************************************************************************
240  *
241  *  Handler for device events.
242  *  Certain device events require that sockets be unconnected.
243  *
244  **************************************************************************/
245
246 static void pppoe_flush_dev(struct net_device *dev)
247 {
248         int hash;
249         BUG_ON(dev == NULL);
250
251         write_lock_bh(&pppoe_hash_lock);
252         for (hash = 0; hash < PPPOE_HASH_SIZE; hash++) {
253                 struct pppox_sock *po = item_hash_table[hash];
254
255                 while (po != NULL) {
256                         struct sock *sk = sk_pppox(po);
257                         if (po->pppoe_dev != dev) {
258                                 po = po->next;
259                                 continue;
260                         }
261                         po->pppoe_dev = NULL;
262                         dev_put(dev);
263
264
265                         /* We always grab the socket lock, followed by the
266                          * pppoe_hash_lock, in that order.  Since we should
267                          * hold the sock lock while doing any unbinding,
268                          * we need to release the lock we're holding.
269                          * Hold a reference to the sock so it doesn't disappear
270                          * as we're jumping between locks.
271                          */
272
273                         sock_hold(sk);
274
275                         write_unlock_bh(&pppoe_hash_lock);
276                         lock_sock(sk);
277
278                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
279                                 pppox_unbind_sock(sk);
280                                 sk->sk_state = PPPOX_ZOMBIE;
281                                 sk->sk_state_change(sk);
282                         }
283
284                         release_sock(sk);
285                         sock_put(sk);
286
287                         /* Restart scan at the beginning of this hash chain.
288                          * While the lock was dropped the chain contents may
289                          * have changed.
290                          */
291                         write_lock_bh(&pppoe_hash_lock);
292                         po = item_hash_table[hash];
293                 }
294         }
295         write_unlock_bh(&pppoe_hash_lock);
296 }
297
298 static int pppoe_device_event(struct notifier_block *this,
299                               unsigned long event, void *ptr)
300 {
301         struct net_device *dev = (struct net_device *) ptr;
302
303         /* Only look at sockets that are using this specific device. */
304         switch (event) {
305         case NETDEV_CHANGEMTU:
306                 /* A change in mtu is a bad thing, requiring
307                  * LCP re-negotiation.
308                  */
309
310         case NETDEV_GOING_DOWN:
311         case NETDEV_DOWN:
312                 /* Find every socket on this device and kill it. */
313                 pppoe_flush_dev(dev);
314                 break;
315
316         default:
317                 break;
318         };
319
320         return NOTIFY_DONE;
321 }
322
323
324 static struct notifier_block pppoe_notifier = {
325         .notifier_call = pppoe_device_event,
326 };
327
328
329 /************************************************************************
330  *
331  * Do the real work of receiving a PPPoE Session frame.
332  *
333  ***********************************************************************/
334 static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
335 {
336         struct pppox_sock *po = pppox_sk(sk);
337         struct pppox_sock *relay_po;
338
339         if (sk->sk_state & PPPOX_BOUND) {
340                 struct pppoe_hdr *ph = pppoe_hdr(skb);
341                 int len = ntohs(ph->length);
342                 skb_pull_rcsum(skb, sizeof(struct pppoe_hdr));
343                 if (pskb_trim_rcsum(skb, len))
344                         goto abort_kfree;
345
346                 ppp_input(&po->chan, skb);
347         } else if (sk->sk_state & PPPOX_RELAY) {
348                 relay_po = get_item_by_addr(&po->pppoe_relay);
349
350                 if (relay_po == NULL)
351                         goto abort_kfree;
352
353                 if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
354                         goto abort_put;
355
356                 skb_pull(skb, sizeof(struct pppoe_hdr));
357                 if (!__pppoe_xmit(sk_pppox(relay_po), skb))
358                         goto abort_put;
359         } else {
360                 if (sock_queue_rcv_skb(sk, skb))
361                         goto abort_kfree;
362         }
363
364         return NET_RX_SUCCESS;
365
366 abort_put:
367         sock_put(sk_pppox(relay_po));
368
369 abort_kfree:
370         kfree_skb(skb);
371         return NET_RX_DROP;
372 }
373
374 /************************************************************************
375  *
376  * Receive wrapper called in BH context.
377  *
378  ***********************************************************************/
379 static int pppoe_rcv(struct sk_buff *skb,
380                      struct net_device *dev,
381                      struct packet_type *pt,
382                      struct net_device *orig_dev)
383
384 {
385         struct pppoe_hdr *ph;
386         struct pppox_sock *po;
387
388         if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
389                 goto out;
390
391         if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
392                 goto drop;
393
394         ph = pppoe_hdr(skb);
395
396         po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
397         if (po != NULL)
398                 return sk_receive_skb(sk_pppox(po), skb, 0);
399 drop:
400         kfree_skb(skb);
401 out:
402         return NET_RX_DROP;
403 }
404
405 /************************************************************************
406  *
407  * Receive a PPPoE Discovery frame.
408  * This is solely for detection of PADT frames
409  *
410  ***********************************************************************/
411 static int pppoe_disc_rcv(struct sk_buff *skb,
412                           struct net_device *dev,
413                           struct packet_type *pt,
414                           struct net_device *orig_dev)
415
416 {
417         struct pppoe_hdr *ph;
418         struct pppox_sock *po;
419
420         if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
421                 goto abort;
422
423         if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
424                 goto out;
425
426         ph = pppoe_hdr(skb);
427         if (ph->code != PADT_CODE)
428                 goto abort;
429
430         po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
431         if (po) {
432                 struct sock *sk = sk_pppox(po);
433
434                 bh_lock_sock(sk);
435
436                 /* If the user has locked the socket, just ignore
437                  * the packet.  With the way two rcv protocols hook into
438                  * one socket family type, we cannot (easily) distinguish
439                  * what kind of SKB it is during backlog rcv.
440                  */
441                 if (sock_owned_by_user(sk) == 0) {
442                         /* We're no longer connect at the PPPOE layer,
443                          * and must wait for ppp channel to disconnect us.
444                          */
445                         sk->sk_state = PPPOX_ZOMBIE;
446                 }
447
448                 bh_unlock_sock(sk);
449                 sock_put(sk);
450         }
451
452 abort:
453         kfree_skb(skb);
454 out:
455         return NET_RX_SUCCESS; /* Lies... :-) */
456 }
457
458 static struct packet_type pppoes_ptype = {
459         .type   = __constant_htons(ETH_P_PPP_SES),
460         .func   = pppoe_rcv,
461 };
462
463 static struct packet_type pppoed_ptype = {
464         .type   = __constant_htons(ETH_P_PPP_DISC),
465         .func   = pppoe_disc_rcv,
466 };
467
468 static struct proto pppoe_sk_proto = {
469         .name     = "PPPOE",
470         .owner    = THIS_MODULE,
471         .obj_size = sizeof(struct pppox_sock),
472 };
473
474 /***********************************************************************
475  *
476  * Initialize a new struct sock.
477  *
478  **********************************************************************/
479 static int pppoe_create(struct socket *sock)
480 {
481         int error = -ENOMEM;
482         struct sock *sk;
483
484         sk = sk_alloc(PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, 1);
485         if (!sk)
486                 goto out;
487
488         sock_init_data(sock, sk);
489
490         sock->state = SS_UNCONNECTED;
491         sock->ops   = &pppoe_ops;
492
493         sk->sk_backlog_rcv = pppoe_rcv_core;
494         sk->sk_state       = PPPOX_NONE;
495         sk->sk_type        = SOCK_STREAM;
496         sk->sk_family      = PF_PPPOX;
497         sk->sk_protocol    = PX_PROTO_OE;
498
499         error = 0;
500 out:    return error;
501 }
502
503 static int pppoe_release(struct socket *sock)
504 {
505         struct sock *sk = sock->sk;
506         struct pppox_sock *po;
507
508         if (!sk)
509                 return 0;
510
511         lock_sock(sk);
512         if (sock_flag(sk, SOCK_DEAD)){
513                 release_sock(sk);
514                 return -EBADF;
515         }
516
517         pppox_unbind_sock(sk);
518
519         /* Signal the death of the socket. */
520         sk->sk_state = PPPOX_DEAD;
521
522
523         /* Write lock on hash lock protects the entire "po" struct from
524          * concurrent updates via pppoe_flush_dev. The "po" struct should
525          * be considered part of the hash table contents, thus protected
526          * by the hash table lock */
527         write_lock_bh(&pppoe_hash_lock);
528
529         po = pppox_sk(sk);
530         if (po->pppoe_pa.sid) {
531                 __delete_item(po->pppoe_pa.sid,
532                               po->pppoe_pa.remote, po->pppoe_ifindex);
533         }
534
535         if (po->pppoe_dev) {
536                 dev_put(po->pppoe_dev);
537                 po->pppoe_dev = NULL;
538         }
539
540         write_unlock_bh(&pppoe_hash_lock);
541
542         sock_orphan(sk);
543         sock->sk = NULL;
544
545         skb_queue_purge(&sk->sk_receive_queue);
546         release_sock(sk);
547         sock_put(sk);
548
549         return 0;
550 }
551
552
553 static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
554                   int sockaddr_len, int flags)
555 {
556         struct sock *sk = sock->sk;
557         struct net_device *dev;
558         struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr;
559         struct pppox_sock *po = pppox_sk(sk);
560         int error;
561
562         lock_sock(sk);
563
564         error = -EINVAL;
565         if (sp->sa_protocol != PX_PROTO_OE)
566                 goto end;
567
568         /* Check for already bound sockets */
569         error = -EBUSY;
570         if ((sk->sk_state & PPPOX_CONNECTED) && sp->sa_addr.pppoe.sid)
571                 goto end;
572
573         /* Check for already disconnected sockets, on attempts to disconnect */
574         error = -EALREADY;
575         if ((sk->sk_state & PPPOX_DEAD) && !sp->sa_addr.pppoe.sid )
576                 goto end;
577
578         error = 0;
579         if (po->pppoe_pa.sid) {
580                 pppox_unbind_sock(sk);
581
582                 /* Delete the old binding */
583                 delete_item(po->pppoe_pa.sid,po->pppoe_pa.remote,po->pppoe_ifindex);
584
585                 if(po->pppoe_dev)
586                         dev_put(po->pppoe_dev);
587
588                 memset(sk_pppox(po) + 1, 0,
589                        sizeof(struct pppox_sock) - sizeof(struct sock));
590
591                 sk->sk_state = PPPOX_NONE;
592         }
593
594         /* Don't re-bind if sid==0 */
595         if (sp->sa_addr.pppoe.sid != 0) {
596                 dev = dev_get_by_name(sp->sa_addr.pppoe.dev);
597
598                 error = -ENODEV;
599                 if (!dev)
600                         goto end;
601
602                 po->pppoe_dev = dev;
603                 po->pppoe_ifindex = dev->ifindex;
604
605                 write_lock_bh(&pppoe_hash_lock);
606                 if (!(dev->flags & IFF_UP)){
607                         write_unlock_bh(&pppoe_hash_lock);
608                         goto err_put;
609                 }
610
611                 memcpy(&po->pppoe_pa,
612                        &sp->sa_addr.pppoe,
613                        sizeof(struct pppoe_addr));
614
615                 error = __set_item(po);
616                 write_unlock_bh(&pppoe_hash_lock);
617                 if (error < 0)
618                         goto err_put;
619
620                 po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
621                                    dev->hard_header_len);
622
623                 po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr);
624                 po->chan.private = sk;
625                 po->chan.ops = &pppoe_chan_ops;
626
627                 error = ppp_register_channel(&po->chan);
628                 if (error)
629                         goto err_put;
630
631                 sk->sk_state = PPPOX_CONNECTED;
632         }
633
634         po->num = sp->sa_addr.pppoe.sid;
635
636  end:
637         release_sock(sk);
638         return error;
639 err_put:
640         if (po->pppoe_dev) {
641                 dev_put(po->pppoe_dev);
642                 po->pppoe_dev = NULL;
643         }
644         goto end;
645 }
646
647
648 static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
649                   int *usockaddr_len, int peer)
650 {
651         int len = sizeof(struct sockaddr_pppox);
652         struct sockaddr_pppox sp;
653
654         sp.sa_family    = AF_PPPOX;
655         sp.sa_protocol  = PX_PROTO_OE;
656         memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
657                sizeof(struct pppoe_addr));
658
659         memcpy(uaddr, &sp, len);
660
661         *usockaddr_len = len;
662
663         return 0;
664 }
665
666
667 static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
668                 unsigned long arg)
669 {
670         struct sock *sk = sock->sk;
671         struct pppox_sock *po = pppox_sk(sk);
672         int val;
673         int err;
674
675         switch (cmd) {
676         case PPPIOCGMRU:
677                 err = -ENXIO;
678
679                 if (!(sk->sk_state & PPPOX_CONNECTED))
680                         break;
681
682                 err = -EFAULT;
683                 if (put_user(po->pppoe_dev->mtu -
684                              sizeof(struct pppoe_hdr) -
685                              PPP_HDRLEN,
686                              (int __user *) arg))
687                         break;
688                 err = 0;
689                 break;
690
691         case PPPIOCSMRU:
692                 err = -ENXIO;
693                 if (!(sk->sk_state & PPPOX_CONNECTED))
694                         break;
695
696                 err = -EFAULT;
697                 if (get_user(val,(int __user *) arg))
698                         break;
699
700                 if (val < (po->pppoe_dev->mtu
701                            - sizeof(struct pppoe_hdr)
702                            - PPP_HDRLEN))
703                         err = 0;
704                 else
705                         err = -EINVAL;
706                 break;
707
708         case PPPIOCSFLAGS:
709                 err = -EFAULT;
710                 if (get_user(val, (int __user *) arg))
711                         break;
712                 err = 0;
713                 break;
714
715         case PPPOEIOCSFWD:
716         {
717                 struct pppox_sock *relay_po;
718
719                 err = -EBUSY;
720                 if (sk->sk_state & (PPPOX_BOUND | PPPOX_ZOMBIE | PPPOX_DEAD))
721                         break;
722
723                 err = -ENOTCONN;
724                 if (!(sk->sk_state & PPPOX_CONNECTED))
725                         break;
726
727                 /* PPPoE address from the user specifies an outbound
728                    PPPoE address which frames are forwarded to */
729                 err = -EFAULT;
730                 if (copy_from_user(&po->pppoe_relay,
731                                    (void __user *)arg,
732                                    sizeof(struct sockaddr_pppox)))
733                         break;
734
735                 err = -EINVAL;
736                 if (po->pppoe_relay.sa_family != AF_PPPOX ||
737                     po->pppoe_relay.sa_protocol!= PX_PROTO_OE)
738                         break;
739
740                 /* Check that the socket referenced by the address
741                    actually exists. */
742                 relay_po = get_item_by_addr(&po->pppoe_relay);
743
744                 if (!relay_po)
745                         break;
746
747                 sock_put(sk_pppox(relay_po));
748                 sk->sk_state |= PPPOX_RELAY;
749                 err = 0;
750                 break;
751         }
752
753         case PPPOEIOCDFWD:
754                 err = -EALREADY;
755                 if (!(sk->sk_state & PPPOX_RELAY))
756                         break;
757
758                 sk->sk_state &= ~PPPOX_RELAY;
759                 err = 0;
760                 break;
761
762         default:
763                 err = -ENOTTY;
764         }
765
766         return err;
767 }
768
769
770 static int pppoe_sendmsg(struct kiocb *iocb, struct socket *sock,
771                   struct msghdr *m, size_t total_len)
772 {
773         struct sk_buff *skb;
774         struct sock *sk = sock->sk;
775         struct pppox_sock *po = pppox_sk(sk);
776         int error;
777         struct pppoe_hdr hdr;
778         struct pppoe_hdr *ph;
779         struct net_device *dev;
780         char *start;
781
782         lock_sock(sk);
783         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
784                 error = -ENOTCONN;
785                 goto end;
786         }
787
788         hdr.ver = 1;
789         hdr.type = 1;
790         hdr.code = 0;
791         hdr.sid = po->num;
792
793         dev = po->pppoe_dev;
794
795         error = -EMSGSIZE;
796         if (total_len > (dev->mtu + dev->hard_header_len))
797                 goto end;
798
799
800         skb = sock_wmalloc(sk, total_len + dev->hard_header_len + 32,
801                            0, GFP_KERNEL);
802         if (!skb) {
803                 error = -ENOMEM;
804                 goto end;
805         }
806
807         /* Reserve space for headers. */
808         skb_reserve(skb, dev->hard_header_len);
809         skb_reset_network_header(skb);
810
811         skb->dev = dev;
812
813         skb->priority = sk->sk_priority;
814         skb->protocol = __constant_htons(ETH_P_PPP_SES);
815
816         ph = (struct pppoe_hdr *) skb_put(skb, total_len + sizeof(struct pppoe_hdr));
817         start = (char *) &ph->tag[0];
818
819         error = memcpy_fromiovec(start, m->msg_iov, total_len);
820
821         if (error < 0) {
822                 kfree_skb(skb);
823                 goto end;
824         }
825
826         error = total_len;
827         dev->hard_header(skb, dev, ETH_P_PPP_SES,
828                          po->pppoe_pa.remote, NULL, total_len);
829
830         memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
831
832         ph->length = htons(total_len);
833
834         dev_queue_xmit(skb);
835
836 end:
837         release_sock(sk);
838         return error;
839 }
840
841
842 /************************************************************************
843  *
844  * xmit function for internal use.
845  *
846  ***********************************************************************/
847 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
848 {
849         struct pppox_sock *po = pppox_sk(sk);
850         struct net_device *dev = po->pppoe_dev;
851         struct pppoe_hdr hdr;
852         struct pppoe_hdr *ph;
853         int headroom = skb_headroom(skb);
854         int data_len = skb->len;
855         struct sk_buff *skb2;
856
857         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
858                 goto abort;
859
860         hdr.ver = 1;
861         hdr.type = 1;
862         hdr.code = 0;
863         hdr.sid = po->num;
864         hdr.length = htons(skb->len);
865
866         if (!dev)
867                 goto abort;
868
869         /* Copy the skb if there is no space for the header. */
870         if (headroom < (sizeof(struct pppoe_hdr) + dev->hard_header_len)) {
871                 skb2 = dev_alloc_skb(32+skb->len +
872                                      sizeof(struct pppoe_hdr) +
873                                      dev->hard_header_len);
874
875                 if (skb2 == NULL)
876                         goto abort;
877
878                 skb_reserve(skb2, dev->hard_header_len + sizeof(struct pppoe_hdr));
879                 skb_copy_from_linear_data(skb, skb_put(skb2, skb->len),
880                                           skb->len);
881         } else {
882                 /* Make a clone so as to not disturb the original skb,
883                  * give dev_queue_xmit something it can free.
884                  */
885                 skb2 = skb_clone(skb, GFP_ATOMIC);
886
887                 if (skb2 == NULL)
888                         goto abort;
889         }
890
891         ph = (struct pppoe_hdr *) skb_push(skb2, sizeof(struct pppoe_hdr));
892         memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
893         skb2->protocol = __constant_htons(ETH_P_PPP_SES);
894
895         skb_reset_network_header(skb2);
896
897         skb2->dev = dev;
898
899         dev->hard_header(skb2, dev, ETH_P_PPP_SES,
900                          po->pppoe_pa.remote, NULL, data_len);
901
902         /* We're transmitting skb2, and assuming that dev_queue_xmit
903          * will free it.  The generic ppp layer however, is expecting
904          * that we give back 'skb' (not 'skb2') in case of failure,
905          * but free it in case of success.
906          */
907
908         if (dev_queue_xmit(skb2) < 0)
909                 goto abort;
910
911         kfree_skb(skb);
912         return 1;
913
914 abort:
915         return 0;
916 }
917
918
919 /************************************************************************
920  *
921  * xmit function called by generic PPP driver
922  * sends PPP frame over PPPoE socket
923  *
924  ***********************************************************************/
925 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
926 {
927         struct sock *sk = (struct sock *) chan->private;
928         return __pppoe_xmit(sk, skb);
929 }
930
931
932 static struct ppp_channel_ops pppoe_chan_ops = {
933         .start_xmit = pppoe_xmit,
934 };
935
936 static int pppoe_recvmsg(struct kiocb *iocb, struct socket *sock,
937                   struct msghdr *m, size_t total_len, int flags)
938 {
939         struct sock *sk = sock->sk;
940         struct sk_buff *skb;
941         int error = 0;
942
943         if (sk->sk_state & PPPOX_BOUND) {
944                 error = -EIO;
945                 goto end;
946         }
947
948         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
949                                 flags & MSG_DONTWAIT, &error);
950
951         if (error < 0)
952                 goto end;
953
954         m->msg_namelen = 0;
955
956         if (skb) {
957                 struct pppoe_hdr *ph = pppoe_hdr(skb);
958                 const int len = ntohs(ph->length);
959
960                 error = memcpy_toiovec(m->msg_iov, (unsigned char *) &ph->tag[0], len);
961                 if (error == 0)
962                         error = len;
963         }
964
965         kfree_skb(skb);
966 end:
967         return error;
968 }
969
970 #ifdef CONFIG_PROC_FS
971 static int pppoe_seq_show(struct seq_file *seq, void *v)
972 {
973         struct pppox_sock *po;
974         char *dev_name;
975
976         if (v == SEQ_START_TOKEN) {
977                 seq_puts(seq, "Id       Address              Device\n");
978                 goto out;
979         }
980
981         po = v;
982         dev_name = po->pppoe_pa.dev;
983
984         seq_printf(seq, "%08X %02X:%02X:%02X:%02X:%02X:%02X %8s\n",
985                    po->pppoe_pa.sid,
986                    po->pppoe_pa.remote[0], po->pppoe_pa.remote[1],
987                    po->pppoe_pa.remote[2], po->pppoe_pa.remote[3],
988                    po->pppoe_pa.remote[4], po->pppoe_pa.remote[5], dev_name);
989 out:
990         return 0;
991 }
992
993 static __inline__ struct pppox_sock *pppoe_get_idx(loff_t pos)
994 {
995         struct pppox_sock *po;
996         int i = 0;
997
998         for (; i < PPPOE_HASH_SIZE; i++) {
999                 po = item_hash_table[i];
1000                 while (po) {
1001                         if (!pos--)
1002                                 goto out;
1003                         po = po->next;
1004                 }
1005         }
1006 out:
1007         return po;
1008 }
1009
1010 static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1011 {
1012         loff_t l = *pos;
1013
1014         read_lock_bh(&pppoe_hash_lock);
1015         return l ? pppoe_get_idx(--l) : SEQ_START_TOKEN;
1016 }
1017
1018 static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1019 {
1020         struct pppox_sock *po;
1021
1022         ++*pos;
1023         if (v == SEQ_START_TOKEN) {
1024                 po = pppoe_get_idx(0);
1025                 goto out;
1026         }
1027         po = v;
1028         if (po->next)
1029                 po = po->next;
1030         else {
1031                 int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1032
1033                 while (++hash < PPPOE_HASH_SIZE) {
1034                         po = item_hash_table[hash];
1035                         if (po)
1036                                 break;
1037                 }
1038         }
1039 out:
1040         return po;
1041 }
1042
1043 static void pppoe_seq_stop(struct seq_file *seq, void *v)
1044 {
1045         read_unlock_bh(&pppoe_hash_lock);
1046 }
1047
1048 static struct seq_operations pppoe_seq_ops = {
1049         .start          = pppoe_seq_start,
1050         .next           = pppoe_seq_next,
1051         .stop           = pppoe_seq_stop,
1052         .show           = pppoe_seq_show,
1053 };
1054
1055 static int pppoe_seq_open(struct inode *inode, struct file *file)
1056 {
1057         return seq_open(file, &pppoe_seq_ops);
1058 }
1059
1060 static const struct file_operations pppoe_seq_fops = {
1061         .owner          = THIS_MODULE,
1062         .open           = pppoe_seq_open,
1063         .read           = seq_read,
1064         .llseek         = seq_lseek,
1065         .release        = seq_release,
1066 };
1067
1068 static int __init pppoe_proc_init(void)
1069 {
1070         struct proc_dir_entry *p;
1071
1072         p = create_proc_entry("net/pppoe", S_IRUGO, NULL);
1073         if (!p)
1074                 return -ENOMEM;
1075
1076         p->proc_fops = &pppoe_seq_fops;
1077         return 0;
1078 }
1079 #else /* CONFIG_PROC_FS */
1080 static inline int pppoe_proc_init(void) { return 0; }
1081 #endif /* CONFIG_PROC_FS */
1082
1083 static const struct proto_ops pppoe_ops = {
1084     .family             = AF_PPPOX,
1085     .owner              = THIS_MODULE,
1086     .release            = pppoe_release,
1087     .bind               = sock_no_bind,
1088     .connect            = pppoe_connect,
1089     .socketpair         = sock_no_socketpair,
1090     .accept             = sock_no_accept,
1091     .getname            = pppoe_getname,
1092     .poll               = datagram_poll,
1093     .listen             = sock_no_listen,
1094     .shutdown           = sock_no_shutdown,
1095     .setsockopt         = sock_no_setsockopt,
1096     .getsockopt         = sock_no_getsockopt,
1097     .sendmsg            = pppoe_sendmsg,
1098     .recvmsg            = pppoe_recvmsg,
1099     .mmap               = sock_no_mmap,
1100     .ioctl              = pppox_ioctl,
1101 };
1102
1103 static struct pppox_proto pppoe_proto = {
1104     .create     = pppoe_create,
1105     .ioctl      = pppoe_ioctl,
1106     .owner      = THIS_MODULE,
1107 };
1108
1109
1110 static int __init pppoe_init(void)
1111 {
1112         int err = proto_register(&pppoe_sk_proto, 0);
1113
1114         if (err)
1115                 goto out;
1116
1117         err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1118         if (err)
1119                 goto out_unregister_pppoe_proto;
1120
1121         err = pppoe_proc_init();
1122         if (err)
1123                 goto out_unregister_pppox_proto;
1124
1125         dev_add_pack(&pppoes_ptype);
1126         dev_add_pack(&pppoed_ptype);
1127         register_netdevice_notifier(&pppoe_notifier);
1128 out:
1129         return err;
1130 out_unregister_pppox_proto:
1131         unregister_pppox_proto(PX_PROTO_OE);
1132 out_unregister_pppoe_proto:
1133         proto_unregister(&pppoe_sk_proto);
1134         goto out;
1135 }
1136
1137 static void __exit pppoe_exit(void)
1138 {
1139         unregister_pppox_proto(PX_PROTO_OE);
1140         dev_remove_pack(&pppoes_ptype);
1141         dev_remove_pack(&pppoed_ptype);
1142         unregister_netdevice_notifier(&pppoe_notifier);
1143         remove_proc_entry("net/pppoe", NULL);
1144         proto_unregister(&pppoe_sk_proto);
1145 }
1146
1147 module_init(pppoe_init);
1148 module_exit(pppoe_exit);
1149
1150 MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1151 MODULE_DESCRIPTION("PPP over Ethernet driver");
1152 MODULE_LICENSE("GPL");
1153 MODULE_ALIAS_NETPROTO(PF_PPPOX);