blob: 3817c35546413340910cec5502a8b790ef735707 [file] [log] [blame]
James Chapman0d767512010-04-02 06:19:00 +00001/*
2 * L2TPv3 IP encapsulation support
3 *
4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
Joe Perchesa4ca44f2012-05-16 09:55:56 +000012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
Eric Dumazet5b1bb4c2017-02-09 16:15:52 -080014#include <asm/ioctls.h>
James Chapman0d767512010-04-02 06:19:00 +000015#include <linux/icmp.h>
16#include <linux/module.h>
17#include <linux/skbuff.h>
18#include <linux/random.h>
19#include <linux/socket.h>
20#include <linux/l2tp.h>
21#include <linux/in.h>
22#include <net/sock.h>
23#include <net/ip.h>
24#include <net/icmp.h>
25#include <net/udp.h>
26#include <net/inet_common.h>
James Chapman0d767512010-04-02 06:19:00 +000027#include <net/tcp_states.h>
28#include <net/protocol.h>
29#include <net/xfrm.h>
30
31#include "l2tp_core.h"
32
33struct l2tp_ip_sock {
34 /* inet_sock has to be the first member of l2tp_ip_sock */
35 struct inet_sock inet;
36
James Chapmanc8657fd2012-04-29 21:48:48 +000037 u32 conn_id;
38 u32 peer_conn_id;
James Chapman0d767512010-04-02 06:19:00 +000039};
40
41static DEFINE_RWLOCK(l2tp_ip_lock);
42static struct hlist_head l2tp_ip_table;
43static struct hlist_head l2tp_ip_bind_table;
44
45static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
46{
47 return (struct l2tp_ip_sock *)sk;
48}
49
Guillaume Naultd2d74d02016-12-30 19:48:20 +010050static struct sock *__l2tp_ip_bind_lookup(const struct net *net, __be32 laddr,
51 __be32 raddr, int dif, u32 tunnel_id)
James Chapman0d767512010-04-02 06:19:00 +000052{
James Chapman0d767512010-04-02 06:19:00 +000053 struct sock *sk;
54
Sasha Levinb67bfe02013-02-27 17:06:00 -080055 sk_for_each_bound(sk, &l2tp_ip_bind_table) {
James Chapman0d767512010-04-02 06:19:00 +000056 struct inet_sock *inet = inet_sk(sk);
57 struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
58
59 if (l2tp == NULL)
60 continue;
61
62 if ((l2tp->conn_id == tunnel_id) &&
Eric Dumazete83726b2010-10-21 04:39:09 -070063 net_eq(sock_net(sk), net) &&
James Chapman0d767512010-04-02 06:19:00 +000064 !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
Guillaume Naultd2d74d02016-12-30 19:48:20 +010065 (!inet->inet_daddr || !raddr || inet->inet_daddr == raddr) &&
Guillaume Naultdf90e682016-11-29 13:09:47 +010066 (!sk->sk_bound_dev_if || !dif ||
67 sk->sk_bound_dev_if == dif))
James Chapman0d767512010-04-02 06:19:00 +000068 goto found;
69 }
70
71 sk = NULL;
72found:
73 return sk;
74}
75
James Chapman0d767512010-04-02 06:19:00 +000076/* When processing receive frames, there are two cases to
77 * consider. Data frames consist of a non-zero session-id and an
78 * optional cookie. Control frames consist of a regular L2TP header
79 * preceded by 32-bits of zeros.
80 *
81 * L2TPv3 Session Header Over IP
82 *
83 * 0 1 2 3
84 * 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
85 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
86 * | Session ID |
87 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
88 * | Cookie (optional, maximum 64 bits)...
89 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
90 * |
91 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
92 *
93 * L2TPv3 Control Message Header Over IP
94 *
95 * 0 1 2 3
96 * 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
97 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
98 * | (32 bits of zeros) |
99 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
100 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
101 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
102 * | Control Connection ID |
103 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
104 * | Ns | Nr |
105 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 *
107 * All control frames are passed to userspace.
108 */
109static int l2tp_ip_recv(struct sk_buff *skb)
110{
David S. Miller9d6ddb12013-02-05 14:36:02 -0500111 struct net *net = dev_net(skb->dev);
James Chapman0d767512010-04-02 06:19:00 +0000112 struct sock *sk;
113 u32 session_id;
114 u32 tunnel_id;
115 unsigned char *ptr, *optr;
116 struct l2tp_session *session;
117 struct l2tp_tunnel *tunnel = NULL;
Guillaume Naulte2c7c3f2017-11-03 16:49:00 +0100118 struct iphdr *iph;
James Chapman0d767512010-04-02 06:19:00 +0000119 int length;
James Chapman0d767512010-04-02 06:19:00 +0000120
James Chapman0d767512010-04-02 06:19:00 +0000121 if (!pskb_may_pull(skb, 4))
122 goto discard;
123
Haishuang Yan5745b822016-04-03 22:09:23 +0800124 /* Point to L2TP header */
125 optr = ptr = skb->data;
James Chapman0d767512010-04-02 06:19:00 +0000126 session_id = ntohl(*((__be32 *) ptr));
127 ptr += 4;
128
129 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
130 * the session_id. If it is 0, the packet is a L2TP control
131 * frame and the session_id value can be discarded.
132 */
133 if (session_id == 0) {
134 __skb_pull(skb, 4);
135 goto pass_up;
136 }
137
138 /* Ok, this is a data packet. Lookup the session. */
Guillaume Nault6539c4f2017-03-31 13:02:25 +0200139 session = l2tp_session_get(net, NULL, session_id, true);
140 if (!session)
James Chapman0d767512010-04-02 06:19:00 +0000141 goto discard;
142
143 tunnel = session->tunnel;
Guillaume Nault6539c4f2017-03-31 13:02:25 +0200144 if (!tunnel)
145 goto discard_sess;
James Chapman0d767512010-04-02 06:19:00 +0000146
147 /* Trace packet contents, if enabled */
148 if (tunnel->debug & L2TP_MSG_DATA) {
149 length = min(32u, skb->len);
150 if (!pskb_may_pull(skb, length))
Guillaume Nault6539c4f2017-03-31 13:02:25 +0200151 goto discard_sess;
James Chapman0d767512010-04-02 06:19:00 +0000152
Haishuang Yan5745b822016-04-03 22:09:23 +0800153 /* Point to L2TP header */
154 optr = ptr = skb->data;
155 ptr += 4;
Joe Perchesa4ca44f2012-05-16 09:55:56 +0000156 pr_debug("%s: ip recv\n", tunnel->name);
157 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
James Chapman0d767512010-04-02 06:19:00 +0000158 }
159
Jacob Wen63f7ee62019-01-30 14:55:14 +0800160 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
161 goto discard_sess;
162
James Chapman0d767512010-04-02 06:19:00 +0000163 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
Guillaume Nault6539c4f2017-03-31 13:02:25 +0200164 l2tp_session_dec_refcount(session);
James Chapman0d767512010-04-02 06:19:00 +0000165
166 return 0;
167
168pass_up:
169 /* Get the tunnel_id from the L2TP header */
170 if (!pskb_may_pull(skb, 12))
171 goto discard;
172
173 if ((skb->data[0] & 0xc0) != 0xc0)
174 goto discard;
175
176 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
Guillaume Naulte2c7c3f2017-11-03 16:49:00 +0100177 iph = (struct iphdr *)skb_network_header(skb);
James Chapman0d767512010-04-02 06:19:00 +0000178
Guillaume Naulte2c7c3f2017-11-03 16:49:00 +0100179 read_lock_bh(&l2tp_ip_lock);
180 sk = __l2tp_ip_bind_lookup(net, iph->daddr, iph->saddr, inet_iif(skb),
181 tunnel_id);
182 if (!sk) {
James Chapman0d767512010-04-02 06:19:00 +0000183 read_unlock_bh(&l2tp_ip_lock);
Guillaume Naulte2c7c3f2017-11-03 16:49:00 +0100184 goto discard;
James Chapman0d767512010-04-02 06:19:00 +0000185 }
Guillaume Naulte2c7c3f2017-11-03 16:49:00 +0100186 sock_hold(sk);
187 read_unlock_bh(&l2tp_ip_lock);
James Chapman0d767512010-04-02 06:19:00 +0000188
James Chapman0d767512010-04-02 06:19:00 +0000189 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
190 goto discard_put;
191
192 nf_reset(skb);
193
194 return sk_receive_skb(sk, skb, 1);
195
Guillaume Nault6539c4f2017-03-31 13:02:25 +0200196discard_sess:
197 if (session->deref)
198 session->deref(session);
199 l2tp_session_dec_refcount(session);
200 goto discard;
201
James Chapman0d767512010-04-02 06:19:00 +0000202discard_put:
203 sock_put(sk);
204
205discard:
206 kfree_skb(skb);
207 return 0;
208}
209
Eric Dumazet78320d32020-05-29 11:20:53 -0700210static int l2tp_ip_hash(struct sock *sk)
211{
212 if (sk_unhashed(sk)) {
213 write_lock_bh(&l2tp_ip_lock);
214 sk_add_node(sk, &l2tp_ip_table);
215 write_unlock_bh(&l2tp_ip_lock);
216 }
217 return 0;
218}
219
220static void l2tp_ip_unhash(struct sock *sk)
221{
222 if (sk_unhashed(sk))
223 return;
224 write_lock_bh(&l2tp_ip_lock);
225 sk_del_node_init(sk);
226 write_unlock_bh(&l2tp_ip_lock);
227}
228
James Chapman0d767512010-04-02 06:19:00 +0000229static int l2tp_ip_open(struct sock *sk)
230{
231 /* Prevent autobind. We don't have ports. */
232 inet_sk(sk)->inet_num = IPPROTO_L2TP;
233
Eric Dumazet78320d32020-05-29 11:20:53 -0700234 l2tp_ip_hash(sk);
James Chapman0d767512010-04-02 06:19:00 +0000235 return 0;
236}
237
238static void l2tp_ip_close(struct sock *sk, long timeout)
239{
240 write_lock_bh(&l2tp_ip_lock);
241 hlist_del_init(&sk->sk_bind_node);
James Chapmand1f224a2012-04-10 00:10:42 +0000242 sk_del_node_init(sk);
James Chapman0d767512010-04-02 06:19:00 +0000243 write_unlock_bh(&l2tp_ip_lock);
244 sk_common_release(sk);
245}
246
247static void l2tp_ip_destroy_sock(struct sock *sk)
248{
249 struct sk_buff *skb;
Tom Parkin93606312013-03-19 06:11:15 +0000250 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
James Chapman0d767512010-04-02 06:19:00 +0000251
252 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
253 kfree_skb(skb);
254
Tom Parkin93606312013-03-19 06:11:15 +0000255 if (tunnel) {
256 l2tp_tunnel_closeall(tunnel);
257 sock_put(sk);
258 }
259
James Chapman0d767512010-04-02 06:19:00 +0000260 sk_refcnt_debug_dec(sk);
261}
262
263static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
264{
265 struct inet_sock *inet = inet_sk(sk);
266 struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
David S. Miller9d6ddb12013-02-05 14:36:02 -0500267 struct net *net = sock_net(sk);
James Chapmanc51ce492012-05-29 03:30:42 +0000268 int ret;
James Chapman0d767512010-04-02 06:19:00 +0000269 int chk_addr_ret;
270
James Chapmanc51ce492012-05-29 03:30:42 +0000271 if (addr_len < sizeof(struct sockaddr_l2tpip))
272 return -EINVAL;
273 if (addr->l2tp_family != AF_INET)
274 return -EINVAL;
275
James Chapman0d767512010-04-02 06:19:00 +0000276 lock_sock(sk);
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100277
278 ret = -EINVAL;
Guillaume Nault32c23112016-11-18 22:13:00 +0100279 if (!sock_flag(sk, SOCK_ZAPPED))
280 goto out;
281
James Chapman0d767512010-04-02 06:19:00 +0000282 if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
283 goto out;
284
David S. Miller9d6ddb12013-02-05 14:36:02 -0500285 chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
James Chapman0d767512010-04-02 06:19:00 +0000286 ret = -EADDRNOTAVAIL;
287 if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
288 chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
289 goto out;
290
James Chapmanc9be48d2012-04-10 00:10:43 +0000291 if (addr->l2tp_addr.s_addr)
292 inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
James Chapman0d767512010-04-02 06:19:00 +0000293 if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
294 inet->inet_saddr = 0; /* Use device */
James Chapman0d767512010-04-02 06:19:00 +0000295
296 write_lock_bh(&l2tp_ip_lock);
Guillaume Naultd2d74d02016-12-30 19:48:20 +0100297 if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr, 0,
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100298 sk->sk_bound_dev_if, addr->l2tp_conn_id)) {
299 write_unlock_bh(&l2tp_ip_lock);
300 ret = -EADDRINUSE;
301 goto out;
302 }
303
304 sk_dst_reset(sk);
305 l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
306
James Chapman0d767512010-04-02 06:19:00 +0000307 sk_add_bind_node(sk, &l2tp_ip_bind_table);
308 sk_del_node_init(sk);
309 write_unlock_bh(&l2tp_ip_lock);
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100310
James Chapman0d767512010-04-02 06:19:00 +0000311 ret = 0;
James Chapmanc51ce492012-05-29 03:30:42 +0000312 sock_reset_flag(sk, SOCK_ZAPPED);
313
James Chapman0d767512010-04-02 06:19:00 +0000314out:
315 release_sock(sk);
316
317 return ret;
James Chapman0d767512010-04-02 06:19:00 +0000318}
319
320static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
321{
James Chapman0d767512010-04-02 06:19:00 +0000322 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
James Chapmande3c7a12012-04-29 21:48:47 +0000323 int rc;
James Chapman0d767512010-04-02 06:19:00 +0000324
James Chapman0d767512010-04-02 06:19:00 +0000325 if (addr_len < sizeof(*lsa))
James Chapmande3c7a12012-04-29 21:48:47 +0000326 return -EINVAL;
James Chapman0d767512010-04-02 06:19:00 +0000327
James Chapmande3c7a12012-04-29 21:48:47 +0000328 if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
329 return -EINVAL;
330
David S. Miller2f162702011-05-08 13:39:01 -0700331 lock_sock(sk);
332
Guillaume Nault0382a252016-11-29 13:09:44 +0100333 /* Must bind first - autobinding does not work */
334 if (sock_flag(sk, SOCK_ZAPPED)) {
335 rc = -EINVAL;
336 goto out_sk;
337 }
338
339 rc = __ip4_datagram_connect(sk, uaddr, addr_len);
340 if (rc < 0)
341 goto out_sk;
342
James Chapman0d767512010-04-02 06:19:00 +0000343 l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
344
James Chapman0d767512010-04-02 06:19:00 +0000345 write_lock_bh(&l2tp_ip_lock);
346 hlist_del_init(&sk->sk_bind_node);
347 sk_add_bind_node(sk, &l2tp_ip_bind_table);
348 write_unlock_bh(&l2tp_ip_lock);
349
Guillaume Nault0382a252016-11-29 13:09:44 +0100350out_sk:
David S. Miller2f162702011-05-08 13:39:01 -0700351 release_sock(sk);
Guillaume Nault0382a252016-11-29 13:09:44 +0100352
James Chapman0d767512010-04-02 06:19:00 +0000353 return rc;
354}
355
James Chapmanc51ce492012-05-29 03:30:42 +0000356static int l2tp_ip_disconnect(struct sock *sk, int flags)
357{
358 if (sock_flag(sk, SOCK_ZAPPED))
359 return 0;
360
Eric Dumazet286c72d2016-10-20 09:39:40 -0700361 return __udp_disconnect(sk, flags);
James Chapmanc51ce492012-05-29 03:30:42 +0000362}
363
James Chapman0d767512010-04-02 06:19:00 +0000364static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
365 int *uaddr_len, int peer)
366{
367 struct sock *sk = sock->sk;
368 struct inet_sock *inet = inet_sk(sk);
369 struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
370 struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
371
372 memset(lsa, 0, sizeof(*lsa));
373 lsa->l2tp_family = AF_INET;
374 if (peer) {
375 if (!inet->inet_dport)
376 return -ENOTCONN;
377 lsa->l2tp_conn_id = lsk->peer_conn_id;
378 lsa->l2tp_addr.s_addr = inet->inet_daddr;
379 } else {
380 __be32 addr = inet->inet_rcv_saddr;
381 if (!addr)
382 addr = inet->inet_saddr;
383 lsa->l2tp_conn_id = lsk->conn_id;
384 lsa->l2tp_addr.s_addr = addr;
385 }
386 *uaddr_len = sizeof(*lsa);
387 return 0;
388}
389
390static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
391{
392 int rc;
393
James Chapman0d767512010-04-02 06:19:00 +0000394 /* Charge it to the socket, dropping if the queue is full. */
395 rc = sock_queue_rcv_skb(sk, skb);
396 if (rc < 0)
397 goto drop;
398
399 return 0;
400
401drop:
David S. Miller9d6ddb12013-02-05 14:36:02 -0500402 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
James Chapman0d767512010-04-02 06:19:00 +0000403 kfree_skb(skb);
Paul Hüber837786c2017-02-26 17:58:19 +0100404 return 0;
James Chapman0d767512010-04-02 06:19:00 +0000405}
406
407/* Userspace will call sendmsg() on the tunnel socket to send L2TP
408 * control frames.
409 */
Ying Xue1b784142015-03-02 15:37:48 +0800410static int l2tp_ip_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
James Chapman0d767512010-04-02 06:19:00 +0000411{
412 struct sk_buff *skb;
413 int rc;
James Chapman0d767512010-04-02 06:19:00 +0000414 struct inet_sock *inet = inet_sk(sk);
James Chapman0d767512010-04-02 06:19:00 +0000415 struct rtable *rt = NULL;
David S. Millerfdbb0f02011-05-08 13:48:37 -0700416 struct flowi4 *fl4;
James Chapman0d767512010-04-02 06:19:00 +0000417 int connected = 0;
418 __be32 daddr;
419
David S. Miller2f162702011-05-08 13:39:01 -0700420 lock_sock(sk);
421
422 rc = -ENOTCONN;
James Chapman0d767512010-04-02 06:19:00 +0000423 if (sock_flag(sk, SOCK_DEAD))
David S. Miller2f162702011-05-08 13:39:01 -0700424 goto out;
James Chapman0d767512010-04-02 06:19:00 +0000425
426 /* Get and verify the address. */
427 if (msg->msg_name) {
Steffen Hurrle342dfc32014-01-17 22:53:15 +0100428 DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
David S. Miller2f162702011-05-08 13:39:01 -0700429 rc = -EINVAL;
James Chapman0d767512010-04-02 06:19:00 +0000430 if (msg->msg_namelen < sizeof(*lip))
David S. Miller2f162702011-05-08 13:39:01 -0700431 goto out;
James Chapman0d767512010-04-02 06:19:00 +0000432
433 if (lip->l2tp_family != AF_INET) {
David S. Miller2f162702011-05-08 13:39:01 -0700434 rc = -EAFNOSUPPORT;
James Chapman0d767512010-04-02 06:19:00 +0000435 if (lip->l2tp_family != AF_UNSPEC)
David S. Miller2f162702011-05-08 13:39:01 -0700436 goto out;
James Chapman0d767512010-04-02 06:19:00 +0000437 }
438
439 daddr = lip->l2tp_addr.s_addr;
440 } else {
Sasha Levin84768ed2012-05-02 03:58:43 +0000441 rc = -EDESTADDRREQ;
James Chapman0d767512010-04-02 06:19:00 +0000442 if (sk->sk_state != TCP_ESTABLISHED)
Sasha Levin84768ed2012-05-02 03:58:43 +0000443 goto out;
James Chapman0d767512010-04-02 06:19:00 +0000444
445 daddr = inet->inet_daddr;
446 connected = 1;
447 }
448
449 /* Allocate a socket buffer */
450 rc = -ENOMEM;
451 skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
452 4 + len, 0, GFP_KERNEL);
453 if (!skb)
454 goto error;
455
456 /* Reserve space for headers, putting IP header on 4-byte boundary. */
457 skb_reserve(skb, 2 + NET_SKB_PAD);
458 skb_reset_network_header(skb);
459 skb_reserve(skb, sizeof(struct iphdr));
460 skb_reset_transport_header(skb);
461
462 /* Insert 0 session_id */
463 *((__be32 *) skb_put(skb, 4)) = 0;
464
465 /* Copy user data into skb */
Al Viro6ce8e9c2014-04-06 21:25:44 -0400466 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
James Chapman0d767512010-04-02 06:19:00 +0000467 if (rc < 0) {
468 kfree_skb(skb);
469 goto error;
470 }
471
David S. Millerfdbb0f02011-05-08 13:48:37 -0700472 fl4 = &inet->cork.fl.u.ip4;
James Chapman0d767512010-04-02 06:19:00 +0000473 if (connected)
474 rt = (struct rtable *) __sk_dst_check(sk, 0);
475
Eric Dumazet081b1b12011-06-11 22:27:09 +0000476 rcu_read_lock();
James Chapman0d767512010-04-02 06:19:00 +0000477 if (rt == NULL) {
Eric Dumazet081b1b12011-06-11 22:27:09 +0000478 const struct ip_options_rcu *inet_opt;
Eric Dumazetf6d8bd02011-04-21 09:45:37 +0000479
David S. Miller778865a2011-04-28 13:54:06 -0700480 inet_opt = rcu_dereference(inet->inet_opt);
Eric Dumazetf6d8bd02011-04-21 09:45:37 +0000481
James Chapman0d767512010-04-02 06:19:00 +0000482 /* Use correct destination address if we have options. */
Eric Dumazetf6d8bd02011-04-21 09:45:37 +0000483 if (inet_opt && inet_opt->opt.srr)
484 daddr = inet_opt->opt.faddr;
James Chapman0d767512010-04-02 06:19:00 +0000485
David S. Miller78fbfd82011-03-12 00:00:52 -0500486 /* If this fails, retransmit mechanism of transport layer will
487 * keep trying until route appears or the connection times
488 * itself out.
489 */
David S. Millerfdbb0f02011-05-08 13:48:37 -0700490 rt = ip_route_output_ports(sock_net(sk), fl4, sk,
David S. Miller78fbfd82011-03-12 00:00:52 -0500491 daddr, inet->inet_saddr,
492 inet->inet_dport, inet->inet_sport,
493 sk->sk_protocol, RT_CONN_FLAGS(sk),
494 sk->sk_bound_dev_if);
495 if (IS_ERR(rt))
496 goto no_route;
Eric Dumazet4399a4d2012-06-08 06:25:00 +0000497 if (connected) {
Eric Dumazet081b1b12011-06-11 22:27:09 +0000498 sk_setup_caps(sk, &rt->dst);
Eric Dumazet4399a4d2012-06-08 06:25:00 +0000499 } else {
500 skb_dst_set(skb, &rt->dst);
501 goto xmit;
502 }
James Chapman0d767512010-04-02 06:19:00 +0000503 }
Eric Dumazet081b1b12011-06-11 22:27:09 +0000504
505 /* We dont need to clone dst here, it is guaranteed to not disappear.
506 * __dev_xmit_skb() might force a refcount if needed.
507 */
508 skb_dst_set_noref(skb, &rt->dst);
James Chapman0d767512010-04-02 06:19:00 +0000509
Eric Dumazet4399a4d2012-06-08 06:25:00 +0000510xmit:
James Chapman0d767512010-04-02 06:19:00 +0000511 /* Queue the packet to IP for output */
Eric Dumazetb0270e92014-04-15 12:58:34 -0400512 rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
Eric Dumazet081b1b12011-06-11 22:27:09 +0000513 rcu_read_unlock();
James Chapman0d767512010-04-02 06:19:00 +0000514
515error:
James Chapmanc8657fd2012-04-29 21:48:48 +0000516 if (rc >= 0)
James Chapman0d767512010-04-02 06:19:00 +0000517 rc = len;
James Chapman0d767512010-04-02 06:19:00 +0000518
David S. Miller2f162702011-05-08 13:39:01 -0700519out:
520 release_sock(sk);
James Chapman0d767512010-04-02 06:19:00 +0000521 return rc;
522
523no_route:
Eric Dumazet081b1b12011-06-11 22:27:09 +0000524 rcu_read_unlock();
James Chapman0d767512010-04-02 06:19:00 +0000525 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
526 kfree_skb(skb);
David S. Miller2f162702011-05-08 13:39:01 -0700527 rc = -EHOSTUNREACH;
528 goto out;
James Chapman0d767512010-04-02 06:19:00 +0000529}
530
Ying Xue1b784142015-03-02 15:37:48 +0800531static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
James Chapman0d767512010-04-02 06:19:00 +0000532 size_t len, int noblock, int flags, int *addr_len)
533{
534 struct inet_sock *inet = inet_sk(sk);
James Chapman0d767512010-04-02 06:19:00 +0000535 size_t copied = 0;
536 int err = -EOPNOTSUPP;
Steffen Hurrle342dfc32014-01-17 22:53:15 +0100537 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
James Chapman0d767512010-04-02 06:19:00 +0000538 struct sk_buff *skb;
539
540 if (flags & MSG_OOB)
541 goto out;
542
James Chapman0d767512010-04-02 06:19:00 +0000543 skb = skb_recv_datagram(sk, flags, noblock, &err);
544 if (!skb)
545 goto out;
546
547 copied = skb->len;
548 if (len < copied) {
549 msg->msg_flags |= MSG_TRUNC;
550 copied = len;
551 }
552
David S. Miller51f3d022014-11-05 16:46:40 -0500553 err = skb_copy_datagram_msg(skb, 0, msg, copied);
James Chapman0d767512010-04-02 06:19:00 +0000554 if (err)
555 goto done;
556
557 sock_recv_timestamp(msg, sk, skb);
558
559 /* Copy the address. */
560 if (sin) {
561 sin->sin_family = AF_INET;
562 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
563 sin->sin_port = 0;
564 memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
Hannes Frederic Sowabceaa902013-11-18 04:20:45 +0100565 *addr_len = sizeof(*sin);
James Chapman0d767512010-04-02 06:19:00 +0000566 }
567 if (inet->cmsg_flags)
568 ip_cmsg_recv(msg, skb);
569 if (flags & MSG_TRUNC)
570 copied = skb->len;
571done:
572 skb_free_datagram(sk, skb);
573out:
James Chapmanc8657fd2012-04-29 21:48:48 +0000574 return err ? err : copied;
James Chapman0d767512010-04-02 06:19:00 +0000575}
576
Eric Dumazet5b1bb4c2017-02-09 16:15:52 -0800577int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
578{
579 struct sk_buff *skb;
580 int amount;
581
582 switch (cmd) {
583 case SIOCOUTQ:
584 amount = sk_wmem_alloc_get(sk);
585 break;
586 case SIOCINQ:
587 spin_lock_bh(&sk->sk_receive_queue.lock);
588 skb = skb_peek(&sk->sk_receive_queue);
589 amount = skb ? skb->len : 0;
590 spin_unlock_bh(&sk->sk_receive_queue.lock);
591 break;
592
593 default:
594 return -ENOIOCTLCMD;
595 }
596
597 return put_user(amount, (int __user *)arg);
598}
599EXPORT_SYMBOL(l2tp_ioctl);
600
stephen hemmingerfc130842010-10-21 07:50:46 +0000601static struct proto l2tp_ip_prot = {
James Chapman0d767512010-04-02 06:19:00 +0000602 .name = "L2TP/IP",
603 .owner = THIS_MODULE,
604 .init = l2tp_ip_open,
605 .close = l2tp_ip_close,
606 .bind = l2tp_ip_bind,
607 .connect = l2tp_ip_connect,
James Chapmanc51ce492012-05-29 03:30:42 +0000608 .disconnect = l2tp_ip_disconnect,
Eric Dumazet5b1bb4c2017-02-09 16:15:52 -0800609 .ioctl = l2tp_ioctl,
James Chapman0d767512010-04-02 06:19:00 +0000610 .destroy = l2tp_ip_destroy_sock,
611 .setsockopt = ip_setsockopt,
612 .getsockopt = ip_getsockopt,
613 .sendmsg = l2tp_ip_sendmsg,
614 .recvmsg = l2tp_ip_recvmsg,
615 .backlog_rcv = l2tp_ip_backlog_recv,
Eric Dumazet78320d32020-05-29 11:20:53 -0700616 .hash = l2tp_ip_hash,
617 .unhash = l2tp_ip_unhash,
James Chapman0d767512010-04-02 06:19:00 +0000618 .obj_size = sizeof(struct l2tp_ip_sock),
619#ifdef CONFIG_COMPAT
620 .compat_setsockopt = compat_ip_setsockopt,
621 .compat_getsockopt = compat_ip_getsockopt,
622#endif
623};
624
625static const struct proto_ops l2tp_ip_ops = {
626 .family = PF_INET,
627 .owner = THIS_MODULE,
628 .release = inet_release,
629 .bind = inet_bind,
630 .connect = inet_dgram_connect,
631 .socketpair = sock_no_socketpair,
632 .accept = sock_no_accept,
633 .getname = l2tp_ip_getname,
634 .poll = datagram_poll,
635 .ioctl = inet_ioctl,
636 .listen = sock_no_listen,
637 .shutdown = inet_shutdown,
638 .setsockopt = sock_common_setsockopt,
639 .getsockopt = sock_common_getsockopt,
640 .sendmsg = inet_sendmsg,
641 .recvmsg = sock_common_recvmsg,
642 .mmap = sock_no_mmap,
643 .sendpage = sock_no_sendpage,
644#ifdef CONFIG_COMPAT
645 .compat_setsockopt = compat_sock_common_setsockopt,
646 .compat_getsockopt = compat_sock_common_getsockopt,
647#endif
648};
649
650static struct inet_protosw l2tp_ip_protosw = {
651 .type = SOCK_DGRAM,
652 .protocol = IPPROTO_L2TP,
653 .prot = &l2tp_ip_prot,
654 .ops = &l2tp_ip_ops,
James Chapman0d767512010-04-02 06:19:00 +0000655};
656
657static struct net_protocol l2tp_ip_protocol __read_mostly = {
658 .handler = l2tp_ip_recv,
David S. Miller9d6ddb12013-02-05 14:36:02 -0500659 .netns_ok = 1,
James Chapman0d767512010-04-02 06:19:00 +0000660};
661
662static int __init l2tp_ip_init(void)
663{
664 int err;
665
Joe Perchesa4ca44f2012-05-16 09:55:56 +0000666 pr_info("L2TP IP encapsulation support (L2TPv3)\n");
James Chapman0d767512010-04-02 06:19:00 +0000667
668 err = proto_register(&l2tp_ip_prot, 1);
669 if (err != 0)
670 goto out;
671
672 err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
673 if (err)
674 goto out1;
675
676 inet_register_protosw(&l2tp_ip_protosw);
677 return 0;
678
679out1:
680 proto_unregister(&l2tp_ip_prot);
681out:
682 return err;
683}
684
685static void __exit l2tp_ip_exit(void)
686{
687 inet_unregister_protosw(&l2tp_ip_protosw);
688 inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
689 proto_unregister(&l2tp_ip_prot);
690}
691
692module_init(l2tp_ip_init);
693module_exit(l2tp_ip_exit);
694
695MODULE_LICENSE("GPL");
696MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
697MODULE_DESCRIPTION("L2TP over IP");
698MODULE_VERSION("1.0");
Michal Mareke8d34a882010-12-06 02:39:12 +0000699
Lucas De Marchie9c54992011-04-26 23:28:26 -0700700/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
Michal Mareke8d34a882010-12-06 02:39:12 +0000701 * enums
702 */
703MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
stephen hemminger163c2e22015-09-23 21:33:35 -0700704MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);