xref: /openbmc/linux/drivers/net/ppp/pppoe.c (revision 5fbbd952)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /** -*- linux-c -*- ***********************************************************
3  * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
4  *
5  * PPPoX --- Generic PPP encapsulation socket family
6  * PPPoE --- PPP over Ethernet (RFC 2516)
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 processing.
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  */
54 
55 #include <linux/string.h>
56 #include <linux/module.h>
57 #include <linux/kernel.h>
58 #include <linux/slab.h>
59 #include <linux/errno.h>
60 #include <linux/netdevice.h>
61 #include <linux/net.h>
62 #include <linux/inetdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/skbuff.h>
65 #include <linux/init.h>
66 #include <linux/if_ether.h>
67 #include <linux/if_pppox.h>
68 #include <linux/ppp_channel.h>
69 #include <linux/ppp_defs.h>
70 #include <linux/ppp-ioctl.h>
71 #include <linux/notifier.h>
72 #include <linux/file.h>
73 #include <linux/proc_fs.h>
74 #include <linux/seq_file.h>
75 
76 #include <linux/nsproxy.h>
77 #include <net/net_namespace.h>
78 #include <net/netns/generic.h>
79 #include <net/sock.h>
80 
81 #include <linux/uaccess.h>
82 
83 #define PPPOE_HASH_BITS CONFIG_PPPOE_HASH_BITS
84 #define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
85 #define PPPOE_HASH_MASK	(PPPOE_HASH_SIZE - 1)
86 
87 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
88 
89 static const struct proto_ops pppoe_ops;
90 static const struct ppp_channel_ops pppoe_chan_ops;
91 
92 /* per-net private data for this module */
93 static unsigned int pppoe_net_id __read_mostly;
94 struct pppoe_net {
95 	/*
96 	 * we could use _single_ hash table for all
97 	 * nets by injecting net id into the hash but
98 	 * it would increase hash chains and add
99 	 * a few additional math comparisons messy
100 	 * as well, moreover in case of SMP less locking
101 	 * controversy here
102 	 */
103 	struct pppox_sock *hash_table[PPPOE_HASH_SIZE];
104 	rwlock_t hash_lock;
105 };
106 
107 /*
108  * PPPoE could be in the following stages:
109  * 1) Discovery stage (to obtain remote MAC and Session ID)
110  * 2) Session stage (MAC and SID are known)
111  *
112  * Ethernet frames have a special tag for this but
113  * we use simpler approach based on session id
114  */
stage_session(__be16 sid)115 static inline bool stage_session(__be16 sid)
116 {
117 	return sid != 0;
118 }
119 
pppoe_pernet(struct net * net)120 static inline struct pppoe_net *pppoe_pernet(struct net *net)
121 {
122 	return net_generic(net, pppoe_net_id);
123 }
124 
cmp_2_addr(struct pppoe_addr * a,struct pppoe_addr * b)125 static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
126 {
127 	return a->sid == b->sid && ether_addr_equal(a->remote, b->remote);
128 }
129 
cmp_addr(struct pppoe_addr * a,__be16 sid,char * addr)130 static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
131 {
132 	return a->sid == sid && ether_addr_equal(a->remote, addr);
133 }
134 
135 #if 8 % PPPOE_HASH_BITS
136 #error 8 must be a multiple of PPPOE_HASH_BITS
137 #endif
138 
hash_item(__be16 sid,unsigned char * addr)139 static int hash_item(__be16 sid, unsigned char *addr)
140 {
141 	unsigned char hash = 0;
142 	unsigned int i;
143 
144 	for (i = 0; i < ETH_ALEN; i++)
145 		hash ^= addr[i];
146 	for (i = 0; i < sizeof(sid_t) * 8; i += 8)
147 		hash ^= (__force __u32)sid >> i;
148 	for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
149 		hash ^= hash >> i;
150 
151 	return hash & PPPOE_HASH_MASK;
152 }
153 
154 /**********************************************************************
155  *
156  *  Set/get/delete/rehash items  (internal versions)
157  *
158  **********************************************************************/
__get_item(struct pppoe_net * pn,__be16 sid,unsigned char * addr,int ifindex)159 static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
160 				unsigned char *addr, int ifindex)
161 {
162 	int hash = hash_item(sid, addr);
163 	struct pppox_sock *ret;
164 
165 	ret = pn->hash_table[hash];
166 	while (ret) {
167 		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
168 		    ret->pppoe_ifindex == ifindex)
169 			return ret;
170 
171 		ret = ret->next;
172 	}
173 
174 	return NULL;
175 }
176 
__set_item(struct pppoe_net * pn,struct pppox_sock * po)177 static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
178 {
179 	int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
180 	struct pppox_sock *ret;
181 
182 	ret = pn->hash_table[hash];
183 	while (ret) {
184 		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
185 		    ret->pppoe_ifindex == po->pppoe_ifindex)
186 			return -EALREADY;
187 
188 		ret = ret->next;
189 	}
190 
191 	po->next = pn->hash_table[hash];
192 	pn->hash_table[hash] = po;
193 
194 	return 0;
195 }
196 
__delete_item(struct pppoe_net * pn,__be16 sid,char * addr,int ifindex)197 static void __delete_item(struct pppoe_net *pn, __be16 sid,
198 					char *addr, int ifindex)
199 {
200 	int hash = hash_item(sid, addr);
201 	struct pppox_sock *ret, **src;
202 
203 	ret = pn->hash_table[hash];
204 	src = &pn->hash_table[hash];
205 
206 	while (ret) {
207 		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
208 		    ret->pppoe_ifindex == ifindex) {
209 			*src = ret->next;
210 			break;
211 		}
212 
213 		src = &ret->next;
214 		ret = ret->next;
215 	}
216 }
217 
218 /**********************************************************************
219  *
220  *  Set/get/delete/rehash items
221  *
222  **********************************************************************/
get_item(struct pppoe_net * pn,__be16 sid,unsigned char * addr,int ifindex)223 static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
224 					unsigned char *addr, int ifindex)
225 {
226 	struct pppox_sock *po;
227 
228 	read_lock_bh(&pn->hash_lock);
229 	po = __get_item(pn, sid, addr, ifindex);
230 	if (po)
231 		sock_hold(sk_pppox(po));
232 	read_unlock_bh(&pn->hash_lock);
233 
234 	return po;
235 }
236 
get_item_by_addr(struct net * net,struct sockaddr_pppox * sp)237 static inline struct pppox_sock *get_item_by_addr(struct net *net,
238 						struct sockaddr_pppox *sp)
239 {
240 	struct net_device *dev;
241 	struct pppoe_net *pn;
242 	struct pppox_sock *pppox_sock = NULL;
243 
244 	int ifindex;
245 
246 	rcu_read_lock();
247 	dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
248 	if (dev) {
249 		ifindex = dev->ifindex;
250 		pn = pppoe_pernet(net);
251 		pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
252 				sp->sa_addr.pppoe.remote, ifindex);
253 	}
254 	rcu_read_unlock();
255 	return pppox_sock;
256 }
257 
delete_item(struct pppoe_net * pn,__be16 sid,char * addr,int ifindex)258 static inline void delete_item(struct pppoe_net *pn, __be16 sid,
259 					char *addr, int ifindex)
260 {
261 	write_lock_bh(&pn->hash_lock);
262 	__delete_item(pn, sid, addr, ifindex);
263 	write_unlock_bh(&pn->hash_lock);
264 }
265 
266 /***************************************************************************
267  *
268  *  Handler for device events.
269  *  Certain device events require that sockets be unconnected.
270  *
271  **************************************************************************/
272 
pppoe_flush_dev(struct net_device * dev)273 static void pppoe_flush_dev(struct net_device *dev)
274 {
275 	struct pppoe_net *pn;
276 	int i;
277 
278 	pn = pppoe_pernet(dev_net(dev));
279 	write_lock_bh(&pn->hash_lock);
280 	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
281 		struct pppox_sock *po = pn->hash_table[i];
282 		struct sock *sk;
283 
284 		while (po) {
285 			while (po && po->pppoe_dev != dev) {
286 				po = po->next;
287 			}
288 
289 			if (!po)
290 				break;
291 
292 			sk = sk_pppox(po);
293 
294 			/* We always grab the socket lock, followed by the
295 			 * hash_lock, in that order.  Since we should hold the
296 			 * sock lock while doing any unbinding, we need to
297 			 * release the lock we're holding.  Hold a reference to
298 			 * the sock so it doesn't disappear as we're jumping
299 			 * between locks.
300 			 */
301 
302 			sock_hold(sk);
303 			write_unlock_bh(&pn->hash_lock);
304 			lock_sock(sk);
305 
306 			if (po->pppoe_dev == dev &&
307 			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
308 				pppox_unbind_sock(sk);
309 				sk->sk_state_change(sk);
310 				po->pppoe_dev = NULL;
311 				dev_put(dev);
312 			}
313 
314 			release_sock(sk);
315 			sock_put(sk);
316 
317 			/* Restart the process from the start of the current
318 			 * hash chain. We dropped locks so the world may have
319 			 * change from underneath us.
320 			 */
321 
322 			BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
323 			write_lock_bh(&pn->hash_lock);
324 			po = pn->hash_table[i];
325 		}
326 	}
327 	write_unlock_bh(&pn->hash_lock);
328 }
329 
pppoe_device_event(struct notifier_block * this,unsigned long event,void * ptr)330 static int pppoe_device_event(struct notifier_block *this,
331 			      unsigned long event, void *ptr)
332 {
333 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
334 
335 	/* Only look at sockets that are using this specific device. */
336 	switch (event) {
337 	case NETDEV_CHANGEADDR:
338 	case NETDEV_CHANGEMTU:
339 		/* A change in mtu or address is a bad thing, requiring
340 		 * LCP re-negotiation.
341 		 */
342 
343 	case NETDEV_GOING_DOWN:
344 	case NETDEV_DOWN:
345 		/* Find every socket on this device and kill it. */
346 		pppoe_flush_dev(dev);
347 		break;
348 
349 	default:
350 		break;
351 	}
352 
353 	return NOTIFY_DONE;
354 }
355 
356 static struct notifier_block pppoe_notifier = {
357 	.notifier_call = pppoe_device_event,
358 };
359 
360 /************************************************************************
361  *
362  * Do the real work of receiving a PPPoE Session frame.
363  *
364  ***********************************************************************/
pppoe_rcv_core(struct sock * sk,struct sk_buff * skb)365 static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
366 {
367 	struct pppox_sock *po = pppox_sk(sk);
368 	struct pppox_sock *relay_po;
369 
370 	/* Backlog receive. Semantics of backlog rcv preclude any code from
371 	 * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
372 	 * can't change.
373 	 */
374 
375 	if (skb->pkt_type == PACKET_OTHERHOST)
376 		goto abort_kfree;
377 
378 	if (sk->sk_state & PPPOX_BOUND) {
379 		ppp_input(&po->chan, skb);
380 	} else if (sk->sk_state & PPPOX_RELAY) {
381 		relay_po = get_item_by_addr(sock_net(sk),
382 					    &po->pppoe_relay);
383 		if (relay_po == NULL)
384 			goto abort_kfree;
385 
386 		if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
387 			goto abort_put;
388 
389 		if (!__pppoe_xmit(sk_pppox(relay_po), skb))
390 			goto abort_put;
391 
392 		sock_put(sk_pppox(relay_po));
393 	} else {
394 		if (sock_queue_rcv_skb(sk, skb))
395 			goto abort_kfree;
396 	}
397 
398 	return NET_RX_SUCCESS;
399 
400 abort_put:
401 	sock_put(sk_pppox(relay_po));
402 
403 abort_kfree:
404 	kfree_skb(skb);
405 	return NET_RX_DROP;
406 }
407 
408 /************************************************************************
409  *
410  * Receive wrapper called in BH context.
411  *
412  ***********************************************************************/
pppoe_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)413 static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
414 		     struct packet_type *pt, struct net_device *orig_dev)
415 {
416 	struct pppoe_hdr *ph;
417 	struct pppox_sock *po;
418 	struct pppoe_net *pn;
419 	int len;
420 
421 	skb = skb_share_check(skb, GFP_ATOMIC);
422 	if (!skb)
423 		goto out;
424 
425 	if (skb_mac_header_len(skb) < ETH_HLEN)
426 		goto drop;
427 
428 	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
429 		goto drop;
430 
431 	ph = pppoe_hdr(skb);
432 	len = ntohs(ph->length);
433 
434 	skb_pull_rcsum(skb, sizeof(*ph));
435 	if (skb->len < len)
436 		goto drop;
437 
438 	if (pskb_trim_rcsum(skb, len))
439 		goto drop;
440 
441 	ph = pppoe_hdr(skb);
442 	pn = pppoe_pernet(dev_net(dev));
443 
444 	/* Note that get_item does a sock_hold(), so sk_pppox(po)
445 	 * is known to be safe.
446 	 */
447 	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
448 	if (!po)
449 		goto drop;
450 
451 	return sk_receive_skb(sk_pppox(po), skb, 0);
452 
453 drop:
454 	kfree_skb(skb);
455 out:
456 	return NET_RX_DROP;
457 }
458 
pppoe_unbind_sock_work(struct work_struct * work)459 static void pppoe_unbind_sock_work(struct work_struct *work)
460 {
461 	struct pppox_sock *po = container_of(work, struct pppox_sock,
462 					     proto.pppoe.padt_work);
463 	struct sock *sk = sk_pppox(po);
464 
465 	lock_sock(sk);
466 	if (po->pppoe_dev) {
467 		dev_put(po->pppoe_dev);
468 		po->pppoe_dev = NULL;
469 	}
470 	pppox_unbind_sock(sk);
471 	release_sock(sk);
472 	sock_put(sk);
473 }
474 
475 /************************************************************************
476  *
477  * Receive a PPPoE Discovery frame.
478  * This is solely for detection of PADT frames
479  *
480  ***********************************************************************/
pppoe_disc_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)481 static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
482 			  struct packet_type *pt, struct net_device *orig_dev)
483 
484 {
485 	struct pppoe_hdr *ph;
486 	struct pppox_sock *po;
487 	struct pppoe_net *pn;
488 
489 	skb = skb_share_check(skb, GFP_ATOMIC);
490 	if (!skb)
491 		goto out;
492 
493 	if (skb->pkt_type != PACKET_HOST)
494 		goto abort;
495 
496 	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
497 		goto abort;
498 
499 	ph = pppoe_hdr(skb);
500 	if (ph->code != PADT_CODE)
501 		goto abort;
502 
503 	pn = pppoe_pernet(dev_net(dev));
504 	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
505 	if (po)
506 		if (!schedule_work(&po->proto.pppoe.padt_work))
507 			sock_put(sk_pppox(po));
508 
509 abort:
510 	kfree_skb(skb);
511 out:
512 	return NET_RX_SUCCESS; /* Lies... :-) */
513 }
514 
515 static struct packet_type pppoes_ptype __read_mostly = {
516 	.type	= cpu_to_be16(ETH_P_PPP_SES),
517 	.func	= pppoe_rcv,
518 };
519 
520 static struct packet_type pppoed_ptype __read_mostly = {
521 	.type	= cpu_to_be16(ETH_P_PPP_DISC),
522 	.func	= pppoe_disc_rcv,
523 };
524 
525 static struct proto pppoe_sk_proto __read_mostly = {
526 	.name	  = "PPPOE",
527 	.owner	  = THIS_MODULE,
528 	.obj_size = sizeof(struct pppox_sock),
529 };
530 
531 /***********************************************************************
532  *
533  * Initialize a new struct sock.
534  *
535  **********************************************************************/
pppoe_create(struct net * net,struct socket * sock,int kern)536 static int pppoe_create(struct net *net, struct socket *sock, int kern)
537 {
538 	struct sock *sk;
539 
540 	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, kern);
541 	if (!sk)
542 		return -ENOMEM;
543 
544 	sock_init_data(sock, sk);
545 
546 	sock->state	= SS_UNCONNECTED;
547 	sock->ops	= &pppoe_ops;
548 
549 	sk->sk_backlog_rcv	= pppoe_rcv_core;
550 	sk->sk_state		= PPPOX_NONE;
551 	sk->sk_type		= SOCK_STREAM;
552 	sk->sk_family		= PF_PPPOX;
553 	sk->sk_protocol		= PX_PROTO_OE;
554 
555 	INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
556 		  pppoe_unbind_sock_work);
557 
558 	return 0;
559 }
560 
pppoe_release(struct socket * sock)561 static int pppoe_release(struct socket *sock)
562 {
563 	struct sock *sk = sock->sk;
564 	struct pppox_sock *po;
565 	struct pppoe_net *pn;
566 	struct net *net = NULL;
567 
568 	if (!sk)
569 		return 0;
570 
571 	lock_sock(sk);
572 	if (sock_flag(sk, SOCK_DEAD)) {
573 		release_sock(sk);
574 		return -EBADF;
575 	}
576 
577 	po = pppox_sk(sk);
578 
579 	if (po->pppoe_dev) {
580 		dev_put(po->pppoe_dev);
581 		po->pppoe_dev = NULL;
582 	}
583 
584 	pppox_unbind_sock(sk);
585 
586 	/* Signal the death of the socket. */
587 	sk->sk_state = PPPOX_DEAD;
588 
589 	net = sock_net(sk);
590 	pn = pppoe_pernet(net);
591 
592 	/*
593 	 * protect "po" from concurrent updates
594 	 * on pppoe_flush_dev
595 	 */
596 	delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
597 		    po->pppoe_ifindex);
598 
599 	sock_orphan(sk);
600 	sock->sk = NULL;
601 
602 	skb_queue_purge(&sk->sk_receive_queue);
603 	release_sock(sk);
604 	sock_put(sk);
605 
606 	return 0;
607 }
608 
pppoe_connect(struct socket * sock,struct sockaddr * uservaddr,int sockaddr_len,int flags)609 static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
610 		  int sockaddr_len, int flags)
611 {
612 	struct sock *sk = sock->sk;
613 	struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
614 	struct pppox_sock *po = pppox_sk(sk);
615 	struct net_device *dev = NULL;
616 	struct pppoe_net *pn;
617 	struct net *net = NULL;
618 	int error;
619 
620 	lock_sock(sk);
621 
622 	error = -EINVAL;
623 
624 	if (sockaddr_len != sizeof(struct sockaddr_pppox))
625 		goto end;
626 
627 	if (sp->sa_protocol != PX_PROTO_OE)
628 		goto end;
629 
630 	/* Check for already bound sockets */
631 	error = -EBUSY;
632 	if ((sk->sk_state & PPPOX_CONNECTED) &&
633 	     stage_session(sp->sa_addr.pppoe.sid))
634 		goto end;
635 
636 	/* Check for already disconnected sockets, on attempts to disconnect */
637 	error = -EALREADY;
638 	if ((sk->sk_state & PPPOX_DEAD) &&
639 	     !stage_session(sp->sa_addr.pppoe.sid))
640 		goto end;
641 
642 	error = 0;
643 
644 	/* Delete the old binding */
645 	if (stage_session(po->pppoe_pa.sid)) {
646 		pppox_unbind_sock(sk);
647 		pn = pppoe_pernet(sock_net(sk));
648 		delete_item(pn, po->pppoe_pa.sid,
649 			    po->pppoe_pa.remote, po->pppoe_ifindex);
650 		if (po->pppoe_dev) {
651 			dev_put(po->pppoe_dev);
652 			po->pppoe_dev = NULL;
653 		}
654 
655 		po->pppoe_ifindex = 0;
656 		memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
657 		memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay));
658 		memset(&po->chan, 0, sizeof(po->chan));
659 		po->next = NULL;
660 		po->num = 0;
661 
662 		sk->sk_state = PPPOX_NONE;
663 	}
664 
665 	/* Re-bind in session stage only */
666 	if (stage_session(sp->sa_addr.pppoe.sid)) {
667 		error = -ENODEV;
668 		net = sock_net(sk);
669 		dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
670 		if (!dev)
671 			goto err_put;
672 
673 		po->pppoe_dev = dev;
674 		po->pppoe_ifindex = dev->ifindex;
675 		pn = pppoe_pernet(net);
676 		if (!(dev->flags & IFF_UP)) {
677 			goto err_put;
678 		}
679 
680 		memcpy(&po->pppoe_pa,
681 		       &sp->sa_addr.pppoe,
682 		       sizeof(struct pppoe_addr));
683 
684 		write_lock_bh(&pn->hash_lock);
685 		error = __set_item(pn, po);
686 		write_unlock_bh(&pn->hash_lock);
687 		if (error < 0)
688 			goto err_put;
689 
690 		po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
691 				   dev->hard_header_len);
692 
693 		po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
694 		po->chan.private = sk;
695 		po->chan.ops = &pppoe_chan_ops;
696 
697 		error = ppp_register_net_channel(dev_net(dev), &po->chan);
698 		if (error) {
699 			delete_item(pn, po->pppoe_pa.sid,
700 				    po->pppoe_pa.remote, po->pppoe_ifindex);
701 			goto err_put;
702 		}
703 
704 		sk->sk_state = PPPOX_CONNECTED;
705 	}
706 
707 	po->num = sp->sa_addr.pppoe.sid;
708 
709 end:
710 	release_sock(sk);
711 	return error;
712 err_put:
713 	if (po->pppoe_dev) {
714 		dev_put(po->pppoe_dev);
715 		po->pppoe_dev = NULL;
716 	}
717 	goto end;
718 }
719 
pppoe_getname(struct socket * sock,struct sockaddr * uaddr,int peer)720 static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
721 		  int peer)
722 {
723 	int len = sizeof(struct sockaddr_pppox);
724 	struct sockaddr_pppox sp;
725 
726 	sp.sa_family	= AF_PPPOX;
727 	sp.sa_protocol	= PX_PROTO_OE;
728 	memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
729 	       sizeof(struct pppoe_addr));
730 
731 	memcpy(uaddr, &sp, len);
732 
733 	return len;
734 }
735 
pppoe_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)736 static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
737 		unsigned long arg)
738 {
739 	struct sock *sk = sock->sk;
740 	struct pppox_sock *po = pppox_sk(sk);
741 	int val;
742 	int err;
743 
744 	switch (cmd) {
745 	case PPPIOCGMRU:
746 		err = -ENXIO;
747 		if (!(sk->sk_state & PPPOX_CONNECTED))
748 			break;
749 
750 		err = -EFAULT;
751 		if (put_user(po->pppoe_dev->mtu -
752 			     sizeof(struct pppoe_hdr) -
753 			     PPP_HDRLEN,
754 			     (int __user *)arg))
755 			break;
756 		err = 0;
757 		break;
758 
759 	case PPPIOCSMRU:
760 		err = -ENXIO;
761 		if (!(sk->sk_state & PPPOX_CONNECTED))
762 			break;
763 
764 		err = -EFAULT;
765 		if (get_user(val, (int __user *)arg))
766 			break;
767 
768 		if (val < (po->pppoe_dev->mtu
769 			   - sizeof(struct pppoe_hdr)
770 			   - PPP_HDRLEN))
771 			err = 0;
772 		else
773 			err = -EINVAL;
774 		break;
775 
776 	case PPPIOCSFLAGS:
777 		err = -EFAULT;
778 		if (get_user(val, (int __user *)arg))
779 			break;
780 		err = 0;
781 		break;
782 
783 	case PPPOEIOCSFWD:
784 	{
785 		struct pppox_sock *relay_po;
786 
787 		err = -EBUSY;
788 		if (sk->sk_state & (PPPOX_BOUND | PPPOX_DEAD))
789 			break;
790 
791 		err = -ENOTCONN;
792 		if (!(sk->sk_state & PPPOX_CONNECTED))
793 			break;
794 
795 		/* PPPoE address from the user specifies an outbound
796 		   PPPoE address which frames are forwarded to */
797 		err = -EFAULT;
798 		if (copy_from_user(&po->pppoe_relay,
799 				   (void __user *)arg,
800 				   sizeof(struct sockaddr_pppox)))
801 			break;
802 
803 		err = -EINVAL;
804 		if (po->pppoe_relay.sa_family != AF_PPPOX ||
805 		    po->pppoe_relay.sa_protocol != PX_PROTO_OE)
806 			break;
807 
808 		/* Check that the socket referenced by the address
809 		   actually exists. */
810 		relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
811 		if (!relay_po)
812 			break;
813 
814 		sock_put(sk_pppox(relay_po));
815 		sk->sk_state |= PPPOX_RELAY;
816 		err = 0;
817 		break;
818 	}
819 
820 	case PPPOEIOCDFWD:
821 		err = -EALREADY;
822 		if (!(sk->sk_state & PPPOX_RELAY))
823 			break;
824 
825 		sk->sk_state &= ~PPPOX_RELAY;
826 		err = 0;
827 		break;
828 
829 	default:
830 		err = -ENOTTY;
831 	}
832 
833 	return err;
834 }
835 
pppoe_sendmsg(struct socket * sock,struct msghdr * m,size_t total_len)836 static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
837 			 size_t total_len)
838 {
839 	struct sk_buff *skb;
840 	struct sock *sk = sock->sk;
841 	struct pppox_sock *po = pppox_sk(sk);
842 	int error;
843 	struct pppoe_hdr hdr;
844 	struct pppoe_hdr *ph;
845 	struct net_device *dev;
846 	char *start;
847 	int hlen;
848 
849 	lock_sock(sk);
850 	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
851 		error = -ENOTCONN;
852 		goto end;
853 	}
854 
855 	hdr.ver = 1;
856 	hdr.type = 1;
857 	hdr.code = 0;
858 	hdr.sid = po->num;
859 
860 	dev = po->pppoe_dev;
861 
862 	error = -EMSGSIZE;
863 	if (total_len > (dev->mtu + dev->hard_header_len))
864 		goto end;
865 
866 	hlen = LL_RESERVED_SPACE(dev);
867 	skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len +
868 			   dev->needed_tailroom, 0, GFP_KERNEL);
869 	if (!skb) {
870 		error = -ENOMEM;
871 		goto end;
872 	}
873 
874 	/* Reserve space for headers. */
875 	skb_reserve(skb, hlen);
876 	skb_reset_network_header(skb);
877 
878 	skb->dev = dev;
879 
880 	skb->priority = sk->sk_priority;
881 	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
882 
883 	ph = skb_put(skb, total_len + sizeof(struct pppoe_hdr));
884 	start = (char *)&ph->tag[0];
885 
886 	error = memcpy_from_msg(start, m, total_len);
887 	if (error < 0) {
888 		kfree_skb(skb);
889 		goto end;
890 	}
891 
892 	error = total_len;
893 	dev_hard_header(skb, dev, ETH_P_PPP_SES,
894 			po->pppoe_pa.remote, NULL, total_len);
895 
896 	memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
897 
898 	ph->length = htons(total_len);
899 
900 	dev_queue_xmit(skb);
901 
902 end:
903 	release_sock(sk);
904 	return error;
905 }
906 
907 /************************************************************************
908  *
909  * xmit function for internal use.
910  *
911  ***********************************************************************/
__pppoe_xmit(struct sock * sk,struct sk_buff * skb)912 static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
913 {
914 	struct pppox_sock *po = pppox_sk(sk);
915 	struct net_device *dev = po->pppoe_dev;
916 	struct pppoe_hdr *ph;
917 	int data_len = skb->len;
918 
919 	/* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
920 	 * xmit operations conclude prior to an unregistration call.  Thus
921 	 * sk->sk_state cannot change, so we don't need to do lock_sock().
922 	 * But, we also can't do a lock_sock since that introduces a potential
923 	 * deadlock as we'd reverse the lock ordering used when calling
924 	 * ppp_unregister_channel().
925 	 */
926 
927 	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
928 		goto abort;
929 
930 	if (!dev)
931 		goto abort;
932 
933 	/* Copy the data if there is no space for the header or if it's
934 	 * read-only.
935 	 */
936 	if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph)))
937 		goto abort;
938 
939 	__skb_push(skb, sizeof(*ph));
940 	skb_reset_network_header(skb);
941 
942 	ph = pppoe_hdr(skb);
943 	ph->ver	= 1;
944 	ph->type = 1;
945 	ph->code = 0;
946 	ph->sid	= po->num;
947 	ph->length = htons(data_len);
948 
949 	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
950 	skb->dev = dev;
951 
952 	dev_hard_header(skb, dev, ETH_P_PPP_SES,
953 			po->pppoe_pa.remote, NULL, data_len);
954 
955 	dev_queue_xmit(skb);
956 	return 1;
957 
958 abort:
959 	kfree_skb(skb);
960 	return 1;
961 }
962 
963 /************************************************************************
964  *
965  * xmit function called by generic PPP driver
966  * sends PPP frame over PPPoE socket
967  *
968  ***********************************************************************/
pppoe_xmit(struct ppp_channel * chan,struct sk_buff * skb)969 static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
970 {
971 	struct sock *sk = chan->private;
972 	return __pppoe_xmit(sk, skb);
973 }
974 
pppoe_fill_forward_path(struct net_device_path_ctx * ctx,struct net_device_path * path,const struct ppp_channel * chan)975 static int pppoe_fill_forward_path(struct net_device_path_ctx *ctx,
976 				   struct net_device_path *path,
977 				   const struct ppp_channel *chan)
978 {
979 	struct sock *sk = chan->private;
980 	struct pppox_sock *po = pppox_sk(sk);
981 	struct net_device *dev = po->pppoe_dev;
982 
983 	if (sock_flag(sk, SOCK_DEAD) ||
984 	    !(sk->sk_state & PPPOX_CONNECTED) || !dev)
985 		return -1;
986 
987 	path->type = DEV_PATH_PPPOE;
988 	path->encap.proto = htons(ETH_P_PPP_SES);
989 	path->encap.id = be16_to_cpu(po->num);
990 	memcpy(path->encap.h_dest, po->pppoe_pa.remote, ETH_ALEN);
991 	memcpy(ctx->daddr, po->pppoe_pa.remote, ETH_ALEN);
992 	path->dev = ctx->dev;
993 	ctx->dev = dev;
994 
995 	return 0;
996 }
997 
998 static const struct ppp_channel_ops pppoe_chan_ops = {
999 	.start_xmit = pppoe_xmit,
1000 	.fill_forward_path = pppoe_fill_forward_path,
1001 };
1002 
pppoe_recvmsg(struct socket * sock,struct msghdr * m,size_t total_len,int flags)1003 static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
1004 			 size_t total_len, int flags)
1005 {
1006 	struct sock *sk = sock->sk;
1007 	struct sk_buff *skb;
1008 	int error = 0;
1009 
1010 	if (sk->sk_state & PPPOX_BOUND)
1011 		return -EIO;
1012 
1013 	skb = skb_recv_datagram(sk, flags, &error);
1014 	if (!skb)
1015 		return error;
1016 
1017 	total_len = min_t(size_t, total_len, skb->len);
1018 	error = skb_copy_datagram_msg(skb, 0, m, total_len);
1019 	if (error == 0) {
1020 		consume_skb(skb);
1021 		return total_len;
1022 	}
1023 
1024 	kfree_skb(skb);
1025 	return error;
1026 }
1027 
1028 #ifdef CONFIG_PROC_FS
pppoe_seq_show(struct seq_file * seq,void * v)1029 static int pppoe_seq_show(struct seq_file *seq, void *v)
1030 {
1031 	struct pppox_sock *po;
1032 	char *dev_name;
1033 
1034 	if (v == SEQ_START_TOKEN) {
1035 		seq_puts(seq, "Id       Address              Device\n");
1036 		goto out;
1037 	}
1038 
1039 	po = v;
1040 	dev_name = po->pppoe_pa.dev;
1041 
1042 	seq_printf(seq, "%08X %pM %8s\n",
1043 		po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
1044 out:
1045 	return 0;
1046 }
1047 
pppoe_get_idx(struct pppoe_net * pn,loff_t pos)1048 static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
1049 {
1050 	struct pppox_sock *po;
1051 	int i;
1052 
1053 	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
1054 		po = pn->hash_table[i];
1055 		while (po) {
1056 			if (!pos--)
1057 				goto out;
1058 			po = po->next;
1059 		}
1060 	}
1061 
1062 out:
1063 	return po;
1064 }
1065 
pppoe_seq_start(struct seq_file * seq,loff_t * pos)1066 static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1067 	__acquires(pn->hash_lock)
1068 {
1069 	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1070 	loff_t l = *pos;
1071 
1072 	read_lock_bh(&pn->hash_lock);
1073 	return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
1074 }
1075 
pppoe_seq_next(struct seq_file * seq,void * v,loff_t * pos)1076 static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1077 {
1078 	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1079 	struct pppox_sock *po;
1080 
1081 	++*pos;
1082 	if (v == SEQ_START_TOKEN) {
1083 		po = pppoe_get_idx(pn, 0);
1084 		goto out;
1085 	}
1086 	po = v;
1087 	if (po->next)
1088 		po = po->next;
1089 	else {
1090 		int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1091 
1092 		po = NULL;
1093 		while (++hash < PPPOE_HASH_SIZE) {
1094 			po = pn->hash_table[hash];
1095 			if (po)
1096 				break;
1097 		}
1098 	}
1099 
1100 out:
1101 	return po;
1102 }
1103 
pppoe_seq_stop(struct seq_file * seq,void * v)1104 static void pppoe_seq_stop(struct seq_file *seq, void *v)
1105 	__releases(pn->hash_lock)
1106 {
1107 	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1108 	read_unlock_bh(&pn->hash_lock);
1109 }
1110 
1111 static const struct seq_operations pppoe_seq_ops = {
1112 	.start		= pppoe_seq_start,
1113 	.next		= pppoe_seq_next,
1114 	.stop		= pppoe_seq_stop,
1115 	.show		= pppoe_seq_show,
1116 };
1117 #endif /* CONFIG_PROC_FS */
1118 
1119 static const struct proto_ops pppoe_ops = {
1120 	.family		= AF_PPPOX,
1121 	.owner		= THIS_MODULE,
1122 	.release	= pppoe_release,
1123 	.bind		= sock_no_bind,
1124 	.connect	= pppoe_connect,
1125 	.socketpair	= sock_no_socketpair,
1126 	.accept		= sock_no_accept,
1127 	.getname	= pppoe_getname,
1128 	.poll		= datagram_poll,
1129 	.listen		= sock_no_listen,
1130 	.shutdown	= sock_no_shutdown,
1131 	.sendmsg	= pppoe_sendmsg,
1132 	.recvmsg	= pppoe_recvmsg,
1133 	.mmap		= sock_no_mmap,
1134 	.ioctl		= pppox_ioctl,
1135 #ifdef CONFIG_COMPAT
1136 	.compat_ioctl	= pppox_compat_ioctl,
1137 #endif
1138 };
1139 
1140 static const struct pppox_proto pppoe_proto = {
1141 	.create	= pppoe_create,
1142 	.ioctl	= pppoe_ioctl,
1143 	.owner	= THIS_MODULE,
1144 };
1145 
pppoe_init_net(struct net * net)1146 static __net_init int pppoe_init_net(struct net *net)
1147 {
1148 	struct pppoe_net *pn = pppoe_pernet(net);
1149 	struct proc_dir_entry *pde;
1150 
1151 	rwlock_init(&pn->hash_lock);
1152 
1153 	pde = proc_create_net("pppoe", 0444, net->proc_net,
1154 			&pppoe_seq_ops, sizeof(struct seq_net_private));
1155 #ifdef CONFIG_PROC_FS
1156 	if (!pde)
1157 		return -ENOMEM;
1158 #endif
1159 
1160 	return 0;
1161 }
1162 
pppoe_exit_net(struct net * net)1163 static __net_exit void pppoe_exit_net(struct net *net)
1164 {
1165 	remove_proc_entry("pppoe", net->proc_net);
1166 }
1167 
1168 static struct pernet_operations pppoe_net_ops = {
1169 	.init = pppoe_init_net,
1170 	.exit = pppoe_exit_net,
1171 	.id   = &pppoe_net_id,
1172 	.size = sizeof(struct pppoe_net),
1173 };
1174 
pppoe_init(void)1175 static int __init pppoe_init(void)
1176 {
1177 	int err;
1178 
1179 	err = register_pernet_device(&pppoe_net_ops);
1180 	if (err)
1181 		goto out;
1182 
1183 	err = proto_register(&pppoe_sk_proto, 0);
1184 	if (err)
1185 		goto out_unregister_net_ops;
1186 
1187 	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1188 	if (err)
1189 		goto out_unregister_pppoe_proto;
1190 
1191 	dev_add_pack(&pppoes_ptype);
1192 	dev_add_pack(&pppoed_ptype);
1193 	register_netdevice_notifier(&pppoe_notifier);
1194 
1195 	return 0;
1196 
1197 out_unregister_pppoe_proto:
1198 	proto_unregister(&pppoe_sk_proto);
1199 out_unregister_net_ops:
1200 	unregister_pernet_device(&pppoe_net_ops);
1201 out:
1202 	return err;
1203 }
1204 
pppoe_exit(void)1205 static void __exit pppoe_exit(void)
1206 {
1207 	unregister_netdevice_notifier(&pppoe_notifier);
1208 	dev_remove_pack(&pppoed_ptype);
1209 	dev_remove_pack(&pppoes_ptype);
1210 	unregister_pppox_proto(PX_PROTO_OE);
1211 	proto_unregister(&pppoe_sk_proto);
1212 	unregister_pernet_device(&pppoe_net_ops);
1213 }
1214 
1215 module_init(pppoe_init);
1216 module_exit(pppoe_exit);
1217 
1218 MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1219 MODULE_DESCRIPTION("PPP over Ethernet driver");
1220 MODULE_LICENSE("GPL");
1221 MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OE);
1222