1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* L2TPv3 IP encapsulation support
3  *
4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5  */
6 
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 
9 #include <asm/ioctls.h>
10 #include <linux/icmp.h>
11 #include <linux/module.h>
12 #include <linux/skbuff.h>
13 #include <linux/random.h>
14 #include <linux/socket.h>
15 #include <linux/l2tp.h>
16 #include <linux/in.h>
17 #include <net/sock.h>
18 #include <net/ip.h>
19 #include <net/icmp.h>
20 #include <net/udp.h>
21 #include <net/inet_common.h>
22 #include <net/tcp_states.h>
23 #include <net/protocol.h>
24 #include <net/xfrm.h>
25 
26 #include "l2tp_core.h"
27 
28 struct l2tp_ip_sock {
29 	/* inet_sock has to be the first member of l2tp_ip_sock */
30 	struct inet_sock	inet;
31 
32 	u32			conn_id;
33 	u32			peer_conn_id;
34 };
35 
36 static DEFINE_RWLOCK(l2tp_ip_lock);
37 static struct hlist_head l2tp_ip_table;
38 static struct hlist_head l2tp_ip_bind_table;
39 
l2tp_ip_sk(const struct sock * sk)40 static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
41 {
42 	return (struct l2tp_ip_sock *)sk;
43 }
44 
__l2tp_ip_bind_lookup(const struct net * net,__be32 laddr,__be32 raddr,int dif,u32 tunnel_id)45 static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
46 					  __be32 raddr, int dif, u32 tunnel_id)
47 {
48 	struct sock *sk;
49 
50 	sk_for_each_bound(sk, &l2tp_ip_bind_table) {
51 		const struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
52 		const struct inet_sock *inet = inet_sk(sk);
53 		int bound_dev_if;
54 
55 		if (!net_eq(sock_net(sk), net))
56 			continue;
57 
58 		bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
59 		if (bound_dev_if && dif && bound_dev_if != dif)
60 			continue;
61 
62 		if (inet->inet_rcv_saddr && laddr &&
63 		    inet->inet_rcv_saddr != laddr)
64 			continue;
65 
66 		if (inet->inet_daddr && raddr && inet->inet_daddr != raddr)
67 			continue;
68 
69 		if (l2tp->conn_id != tunnel_id)
70 			continue;
71 
72 		goto found;
73 	}
74 
75 	sk = NULL;
76 found:
77 	return sk;
78 }
79 
80 /* When processing receive frames, there are two cases to
81  * consider. Data frames consist of a non-zero session-id and an
82  * optional cookie. Control frames consist of a regular L2TP header
83  * preceded by 32-bits of zeros.
84  *
85  * L2TPv3 Session Header Over IP
86  *
87  *  0                   1                   2                   3
88  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
90  * |                           Session ID                          |
91  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
92  * |               Cookie (optional, maximum 64 bits)...
93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
94  *                                                                 |
95  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
96  *
97  * L2TPv3 Control Message Header Over IP
98  *
99  *  0                   1                   2                   3
100  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
102  * |                      (32 bits of zeros)                       |
103  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
104  * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106  * |                     Control Connection ID                     |
107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
108  * |               Ns              |               Nr              |
109  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
110  *
111  * All control frames are passed to userspace.
112  */
l2tp_ip_recv(struct sk_buff * skb)113 static int l2tp_ip_recv(struct sk_buff *skb)
114 {
115 	struct net *net = dev_net(skb->dev);
116 	struct sock *sk;
117 	u32 session_id;
118 	u32 tunnel_id;
119 	unsigned char *ptr, *optr;
120 	struct l2tp_session *session;
121 	struct l2tp_tunnel *tunnel = NULL;
122 	struct iphdr *iph;
123 
124 	if (!pskb_may_pull(skb, 4))
125 		goto discard;
126 
127 	/* Point to L2TP header */
128 	optr = skb->data;
129 	ptr = skb->data;
130 	session_id = ntohl(*((__be32 *)ptr));
131 	ptr += 4;
132 
133 	/* RFC3931: L2TP/IP packets have the first 4 bytes containing
134 	 * the session_id. If it is 0, the packet is a L2TP control
135 	 * frame and the session_id value can be discarded.
136 	 */
137 	if (session_id == 0) {
138 		__skb_pull(skb, 4);
139 		goto pass_up;
140 	}
141 
142 	/* Ok, this is a data packet. Lookup the session. */
143 	session = l2tp_session_get(net, session_id);
144 	if (!session)
145 		goto discard;
146 
147 	tunnel = session->tunnel;
148 	if (!tunnel)
149 		goto discard_sess;
150 
151 	if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
152 		goto discard_sess;
153 
154 	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
155 	l2tp_session_dec_refcount(session);
156 
157 	return 0;
158 
159 pass_up:
160 	/* Get the tunnel_id from the L2TP header */
161 	if (!pskb_may_pull(skb, 12))
162 		goto discard;
163 
164 	if ((skb->data[0] & 0xc0) != 0xc0)
165 		goto discard;
166 
167 	tunnel_id = ntohl(*(__be32 *)&skb->data[4]);
168 	iph = (struct iphdr *)skb_network_header(skb);
169 
170 	read_lock_bh(&l2tp_ip_lock);
171 	sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
172 				   tunnel_id);
173 	if (!sk) {
174 		read_unlock_bh(&l2tp_ip_lock);
175 		goto discard;
176 	}
177 	sock_hold(sk);
178 	read_unlock_bh(&l2tp_ip_lock);
179 
180 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
181 		goto discard_put;
182 
183 	nf_reset_ct(skb);
184 
185 	return sk_receive_skb(sk, skb, 1);
186 
187 discard_sess:
188 	l2tp_session_dec_refcount(session);
189 	goto discard;
190 
191 discard_put:
192 	sock_put(sk);
193 
194 discard:
195 	kfree_skb(skb);
196 	return 0;
197 }
198 
l2tp_ip_hash(struct sock * sk)199 static int l2tp_ip_hash(struct sock *sk)
200 {
201 	if (sk_unhashed(sk)) {
202 		write_lock_bh(&l2tp_ip_lock);
203 		sk_add_node(sk, &l2tp_ip_table);
204 		write_unlock_bh(&l2tp_ip_lock);
205 	}
206 	return 0;
207 }
208 
l2tp_ip_unhash(struct sock * sk)209 static void l2tp_ip_unhash(struct sock *sk)
210 {
211 	if (sk_unhashed(sk))
212 		return;
213 	write_lock_bh(&l2tp_ip_lock);
214 	sk_del_node_init(sk);
215 	write_unlock_bh(&l2tp_ip_lock);
216 }
217 
l2tp_ip_open(struct sock * sk)218 static int l2tp_ip_open(struct sock *sk)
219 {
220 	/* Prevent autobind. We don't have ports. */
221 	inet_sk(sk)->inet_num = IPPROTO_L2TP;
222 
223 	l2tp_ip_hash(sk);
224 	return 0;
225 }
226 
l2tp_ip_close(struct sock * sk,long timeout)227 static void l2tp_ip_close(struct sock *sk, long timeout)
228 {
229 	write_lock_bh(&l2tp_ip_lock);
230 	hlist_del_init(&sk->sk_bind_node);
231 	sk_del_node_init(sk);
232 	write_unlock_bh(&l2tp_ip_lock);
233 	sk_common_release(sk);
234 }
235 
l2tp_ip_destroy_sock(struct sock * sk)236 static void l2tp_ip_destroy_sock(struct sock *sk)
237 {
238 	struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk);
239 	struct sk_buff *skb;
240 
241 	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
242 		kfree_skb(skb);
243 
244 	if (tunnel)
245 		l2tp_tunnel_delete(tunnel);
246 }
247 
l2tp_ip_bind(struct sock * sk,struct sockaddr * uaddr,int addr_len)248 static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
249 {
250 	struct inet_sock *inet = inet_sk(sk);
251 	struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *)uaddr;
252 	struct net *net = sock_net(sk);
253 	int ret;
254 	int chk_addr_ret;
255 
256 	if (addr_len < sizeof(struct sockaddr_l2tpip))
257 		return -EINVAL;
258 	if (addr->l2tp_family != AF_INET)
259 		return -EINVAL;
260 
261 	lock_sock(sk);
262 
263 	ret = -EINVAL;
264 	if (!sock_flag(sk, SOCK_ZAPPED))
265 		goto out;
266 
267 	if (sk->sk_state != TCP_CLOSE)
268 		goto out;
269 
270 	chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
271 	ret = -EADDRNOTAVAIL;
272 	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
273 	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
274 		goto out;
275 
276 	if (addr->l2tp_addr.s_addr) {
277 		inet->inet_rcv_saddr = addr->l2tp_addr.s_addr;
278 		inet->inet_saddr = addr->l2tp_addr.s_addr;
279 	}
280 	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
281 		inet->inet_saddr = 0;  /* Use device */
282 
283 	write_lock_bh(&l2tp_ip_lock);
284 	if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
285 				  sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
286 		write_unlock_bh(&l2tp_ip_lock);
287 		ret = -EADDRINUSE;
288 		goto out;
289 	}
290 
291 	sk_dst_reset(sk);
292 	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
293 
294 	sk_add_bind_node(sk, &l2tp_ip_bind_table);
295 	sk_del_node_init(sk);
296 	write_unlock_bh(&l2tp_ip_lock);
297 
298 	ret = 0;
299 	sock_reset_flag(sk, SOCK_ZAPPED);
300 
301 out:
302 	release_sock(sk);
303 
304 	return ret;
305 }
306 
l2tp_ip_connect(struct sock * sk,struct sockaddr * uaddr,int addr_len)307 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
308 {
309 	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
310 	int rc;
311 
312 	if (addr_len < sizeof(*lsa))
313 		return -EINVAL;
314 
315 	if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
316 		return -EINVAL;
317 
318 	lock_sock(sk);
319 
320 	/* Must bind first - autobinding does not work */
321 	if (sock_flag(sk, SOCK_ZAPPED)) {
322 		rc = -EINVAL;
323 		goto out_sk;
324 	}
325 
326 	rc = __ip4_datagram_connect(sk, uaddr, addr_len);
327 	if (rc < 0)
328 		goto out_sk;
329 
330 	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
331 
332 	write_lock_bh(&l2tp_ip_lock);
333 	hlist_del_init(&sk->sk_bind_node);
334 	sk_add_bind_node(sk, &l2tp_ip_bind_table);
335 	write_unlock_bh(&l2tp_ip_lock);
336 
337 out_sk:
338 	release_sock(sk);
339 
340 	return rc;
341 }
342 
l2tp_ip_disconnect(struct sock * sk,int flags)343 static int l2tp_ip_disconnect(struct sock *sk, int flags)
344 {
345 	if (sock_flag(sk, SOCK_ZAPPED))
346 		return 0;
347 
348 	return __udp_disconnect(sk, flags);
349 }
350 
l2tp_ip_getname(struct socket * sock,struct sockaddr * uaddr,int peer)351 static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
352 			   int peer)
353 {
354 	struct sock *sk		= sock->sk;
355 	struct inet_sock *inet	= inet_sk(sk);
356 	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
357 	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
358 
359 	memset(lsa, 0, sizeof(*lsa));
360 	lsa->l2tp_family = AF_INET;
361 	if (peer) {
362 		if (!inet->inet_dport)
363 			return -ENOTCONN;
364 		lsa->l2tp_conn_id = lsk->peer_conn_id;
365 		lsa->l2tp_addr.s_addr = inet->inet_daddr;
366 	} else {
367 		__be32 addr = inet->inet_rcv_saddr;
368 
369 		if (!addr)
370 			addr = inet->inet_saddr;
371 		lsa->l2tp_conn_id = lsk->conn_id;
372 		lsa->l2tp_addr.s_addr = addr;
373 	}
374 	return sizeof(*lsa);
375 }
376 
l2tp_ip_backlog_recv(struct sock * sk,struct sk_buff * skb)377 static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
378 {
379 	int rc;
380 
381 	/* Charge it to the socket, dropping if the queue is full. */
382 	rc = sock_queue_rcv_skb(sk, skb);
383 	if (rc < 0)
384 		goto drop;
385 
386 	return 0;
387 
388 drop:
389 	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
390 	kfree_skb(skb);
391 	return 0;
392 }
393 
394 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
395  * control frames.
396  */
l2tp_ip_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)397 static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
398 {
399 	struct sk_buff *skb;
400 	int rc;
401 	struct inet_sock *inet = inet_sk(sk);
402 	struct rtable *rt = NULL;
403 	struct flowi4 *fl4;
404 	int connected = 0;
405 	__be32 daddr;
406 
407 	lock_sock(sk);
408 
409 	rc = -ENOTCONN;
410 	if (sock_flag(sk, SOCK_DEAD))
411 		goto out;
412 
413 	/* Get and verify the address. */
414 	if (msg->msg_name) {
415 		DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
416 
417 		rc = -EINVAL;
418 		if (msg->msg_namelen < sizeof(*lip))
419 			goto out;
420 
421 		if (lip->l2tp_family != AF_INET) {
422 			rc = -EAFNOSUPPORT;
423 			if (lip->l2tp_family != AF_UNSPEC)
424 				goto out;
425 		}
426 
427 		daddr = lip->l2tp_addr.s_addr;
428 	} else {
429 		rc = -EDESTADDRREQ;
430 		if (sk->sk_state != TCP_ESTABLISHED)
431 			goto out;
432 
433 		daddr = inet->inet_daddr;
434 		connected = 1;
435 	}
436 
437 	/* Allocate a socket buffer */
438 	rc = -ENOMEM;
439 	skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
440 			   4 + len, 0, GFP_KERNEL);
441 	if (!skb)
442 		goto error;
443 
444 	/* Reserve space for headers, putting IP header on 4-byte boundary. */
445 	skb_reserve(skb, 2 + NET_SKB_PAD);
446 	skb_reset_network_header(skb);
447 	skb_reserve(skb, sizeof(struct iphdr));
448 	skb_reset_transport_header(skb);
449 
450 	/* Insert 0 session_id */
451 	*((__be32 *)skb_put(skb, 4)) = 0;
452 
453 	/* Copy user data into skb */
454 	rc = memcpy_from_msg(skb_put(skb, len), msg, len);
455 	if (rc < 0) {
456 		kfree_skb(skb);
457 		goto error;
458 	}
459 
460 	fl4 = &inet->cork.fl.u.ip4;
461 	if (connected)
462 		rt = (struct rtable *)__sk_dst_check(sk, 0);
463 
464 	rcu_read_lock();
465 	if (!rt) {
466 		const struct ip_options_rcu *inet_opt;
467 
468 		inet_opt = rcu_dereference(inet->inet_opt);
469 
470 		/* Use correct destination address if we have options. */
471 		if (inet_opt && inet_opt->opt.srr)
472 			daddr = inet_opt->opt.faddr;
473 
474 		/* If this fails, retransmit mechanism of transport layer will
475 		 * keep trying until route appears or the connection times
476 		 * itself out.
477 		 */
478 		rt = ip_route_output_ports(sock_net(sk), fl4, sk,
479 					   daddr, inet->inet_saddr,
480 					   inet->inet_dport, inet->inet_sport,
481 					   sk->sk_protocol, RT_CONN_FLAGS(sk),
482 					   sk->sk_bound_dev_if);
483 		if (IS_ERR(rt))
484 			goto no_route;
485 		if (connected) {
486 			sk_setup_caps(sk, &rt->dst);
487 		} else {
488 			skb_dst_set(skb, &rt->dst);
489 			goto xmit;
490 		}
491 	}
492 
493 	/* We don't need to clone dst here, it is guaranteed to not disappear.
494 	 *  __dev_xmit_skb() might force a refcount if needed.
495 	 */
496 	skb_dst_set_noref(skb, &rt->dst);
497 
498 xmit:
499 	/* Queue the packet to IP for output */
500 	rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
501 	rcu_read_unlock();
502 
503 error:
504 	if (rc >= 0)
505 		rc = len;
506 
507 out:
508 	release_sock(sk);
509 	return rc;
510 
511 no_route:
512 	rcu_read_unlock();
513 	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
514 	kfree_skb(skb);
515 	rc = -EHOSTUNREACH;
516 	goto out;
517 }
518 
l2tp_ip_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)519 static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
520 			   size_t len, int flags, int *addr_len)
521 {
522 	struct inet_sock *inet = inet_sk(sk);
523 	size_t copied = 0;
524 	int err = -EOPNOTSUPP;
525 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
526 	struct sk_buff *skb;
527 
528 	if (flags & MSG_OOB)
529 		goto out;
530 
531 	skb = skb_recv_datagram(sk, flags, &err);
532 	if (!skb)
533 		goto out;
534 
535 	copied = skb->len;
536 	if (len < copied) {
537 		msg->msg_flags |= MSG_TRUNC;
538 		copied = len;
539 	}
540 
541 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
542 	if (err)
543 		goto done;
544 
545 	sock_recv_timestamp(msg, sk, skb);
546 
547 	/* Copy the address. */
548 	if (sin) {
549 		sin->sin_family = AF_INET;
550 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
551 		sin->sin_port = 0;
552 		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
553 		*addr_len = sizeof(*sin);
554 	}
555 	if (inet->cmsg_flags)
556 		ip_cmsg_recv(msg, skb);
557 	if (flags & MSG_TRUNC)
558 		copied = skb->len;
559 done:
560 	skb_free_datagram(sk, skb);
561 out:
562 	return err ? err : copied;
563 }
564 
l2tp_ioctl(struct sock * sk,int cmd,unsigned long arg)565 int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
566 {
567 	struct sk_buff *skb;
568 	int amount;
569 
570 	switch (cmd) {
571 	case SIOCOUTQ:
572 		amount = sk_wmem_alloc_get(sk);
573 		break;
574 	case SIOCINQ:
575 		spin_lock_bh(&sk->sk_receive_queue.lock);
576 		skb = skb_peek(&sk->sk_receive_queue);
577 		amount = skb ? skb->len : 0;
578 		spin_unlock_bh(&sk->sk_receive_queue.lock);
579 		break;
580 
581 	default:
582 		return -ENOIOCTLCMD;
583 	}
584 
585 	return put_user(amount, (int __user *)arg);
586 }
587 EXPORT_SYMBOL_GPL(l2tp_ioctl);
588 
589 static struct proto l2tp_ip_prot = {
590 	.name		   = "L2TP/IP",
591 	.owner		   = THIS_MODULE,
592 	.init		   = l2tp_ip_open,
593 	.close		   = l2tp_ip_close,
594 	.bind		   = l2tp_ip_bind,
595 	.connect	   = l2tp_ip_connect,
596 	.disconnect	   = l2tp_ip_disconnect,
597 	.ioctl		   = l2tp_ioctl,
598 	.destroy	   = l2tp_ip_destroy_sock,
599 	.setsockopt	   = ip_setsockopt,
600 	.getsockopt	   = ip_getsockopt,
601 	.sendmsg	   = l2tp_ip_sendmsg,
602 	.recvmsg	   = l2tp_ip_recvmsg,
603 	.backlog_rcv	   = l2tp_ip_backlog_recv,
604 	.hash		   = l2tp_ip_hash,
605 	.unhash		   = l2tp_ip_unhash,
606 	.obj_size	   = sizeof(struct l2tp_ip_sock),
607 };
608 
609 static const struct proto_ops l2tp_ip_ops = {
610 	.family		   = PF_INET,
611 	.owner		   = THIS_MODULE,
612 	.release	   = inet_release,
613 	.bind		   = inet_bind,
614 	.connect	   = inet_dgram_connect,
615 	.socketpair	   = sock_no_socketpair,
616 	.accept		   = sock_no_accept,
617 	.getname	   = l2tp_ip_getname,
618 	.poll		   = datagram_poll,
619 	.ioctl		   = inet_ioctl,
620 	.gettstamp	   = sock_gettstamp,
621 	.listen		   = sock_no_listen,
622 	.shutdown	   = inet_shutdown,
623 	.setsockopt	   = sock_common_setsockopt,
624 	.getsockopt	   = sock_common_getsockopt,
625 	.sendmsg	   = inet_sendmsg,
626 	.recvmsg	   = sock_common_recvmsg,
627 	.mmap		   = sock_no_mmap,
628 	.sendpage	   = sock_no_sendpage,
629 };
630 
631 static struct inet_protosw l2tp_ip_protosw = {
632 	.type		= SOCK_DGRAM,
633 	.protocol	= IPPROTO_L2TP,
634 	.prot		= &l2tp_ip_prot,
635 	.ops		= &l2tp_ip_ops,
636 };
637 
638 static struct net_protocol l2tp_ip_protocol __read_mostly = {
639 	.handler	= l2tp_ip_recv,
640 };
641 
l2tp_ip_init(void)642 static int __init l2tp_ip_init(void)
643 {
644 	int err;
645 
646 	pr_info("L2TP IP encapsulation support (L2TPv3)\n");
647 
648 	err = proto_register(&l2tp_ip_prot, 1);
649 	if (err != 0)
650 		goto out;
651 
652 	err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
653 	if (err)
654 		goto out1;
655 
656 	inet_register_protosw(&l2tp_ip_protosw);
657 	return 0;
658 
659 out1:
660 	proto_unregister(&l2tp_ip_prot);
661 out:
662 	return err;
663 }
664 
l2tp_ip_exit(void)665 static void __exit l2tp_ip_exit(void)
666 {
667 	inet_unregister_protosw(&l2tp_ip_protosw);
668 	inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
669 	proto_unregister(&l2tp_ip_prot);
670 }
671 
672 module_init(l2tp_ip_init);
673 module_exit(l2tp_ip_exit);
674 
675 MODULE_LICENSE("GPL");
676 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
677 MODULE_DESCRIPTION("L2TP over IP");
678 MODULE_VERSION("1.0");
679 
680 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
681  * enums
682  */
683 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
684 MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
685