blob: d148766f40d117c50fc28092173d3686428d1dfc [file] [log] [blame]
Thomas Gleixner2874c5f2019-05-27 08:55:01 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Chris Elstona32e0ee2012-04-29 21:48:54 +00002/*
3 * L2TPv3 IP encapsulation support for IPv6
4 *
5 * Copyright (c) 2012 Katalix Systems Ltd
Chris Elstona32e0ee2012-04-29 21:48:54 +00006 */
7
Joe Perchesa4ca44f2012-05-16 09:55:56 +00008#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
Chris Elstona32e0ee2012-04-29 21:48:54 +000010#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 <linux/in6.h>
18#include <net/sock.h>
19#include <net/ip.h>
20#include <net/icmp.h>
21#include <net/udp.h>
22#include <net/inet_common.h>
23#include <net/inet_hashtables.h>
Craig Gallek496611d2016-02-10 11:50:36 -050024#include <net/inet6_hashtables.h>
Chris Elstona32e0ee2012-04-29 21:48:54 +000025#include <net/tcp_states.h>
26#include <net/protocol.h>
27#include <net/xfrm.h>
28
29#include <net/transp_v6.h>
30#include <net/addrconf.h>
31#include <net/ip6_route.h>
32
33#include "l2tp_core.h"
34
35struct l2tp_ip6_sock {
36 /* inet_sock has to be the first member of l2tp_ip6_sock */
37 struct inet_sock inet;
38
39 u32 conn_id;
40 u32 peer_conn_id;
41
42 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
43 inet6_sk_generic */
44 struct ipv6_pinfo inet6;
45};
46
47static DEFINE_RWLOCK(l2tp_ip6_lock);
48static struct hlist_head l2tp_ip6_table;
49static struct hlist_head l2tp_ip6_bind_table;
50
51static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
52{
53 return (struct l2tp_ip6_sock *)sk;
54}
55
Guillaume Naultbb39b0bd2017-01-06 20:03:55 +010056static struct sock *__l2tp_ip6_bind_lookup(const struct net *net,
57 const struct in6_addr *laddr,
Guillaume Naulta9b2dff2016-12-30 19:48:20 +010058 const struct in6_addr *raddr,
Chris Elstona32e0ee2012-04-29 21:48:54 +000059 int dif, u32 tunnel_id)
60{
Chris Elstona32e0ee2012-04-29 21:48:54 +000061 struct sock *sk;
62
Sasha Levinb67bfe02013-02-27 17:06:00 -080063 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
Guillaume Nault97b84fd2016-12-30 19:48:19 +010064 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
Guillaume Naulta9b2dff2016-12-30 19:48:20 +010065 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
Guillaume Naultbb39b0bd2017-01-06 20:03:55 +010066 const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
Chris Elstona32e0ee2012-04-29 21:48:54 +000067
Guillaume Naultc5fdae02017-01-06 20:03:57 +010068 if (!net_eq(sock_net(sk), net))
69 continue;
70
71 if (sk->sk_bound_dev_if && dif && sk->sk_bound_dev_if != dif)
72 continue;
73
74 if (sk_laddr && !ipv6_addr_any(sk_laddr) &&
75 !ipv6_addr_any(laddr) && !ipv6_addr_equal(sk_laddr, laddr))
76 continue;
77
78 if (!ipv6_addr_any(sk_raddr) && raddr &&
79 !ipv6_addr_any(raddr) && !ipv6_addr_equal(sk_raddr, raddr))
80 continue;
81
82 if (l2tp->conn_id != tunnel_id)
83 continue;
84
85 goto found;
Chris Elstona32e0ee2012-04-29 21:48:54 +000086 }
87
88 sk = NULL;
89found:
90 return sk;
91}
92
Chris Elstona32e0ee2012-04-29 21:48:54 +000093/* When processing receive frames, there are two cases to
94 * consider. Data frames consist of a non-zero session-id and an
95 * optional cookie. Control frames consist of a regular L2TP header
96 * preceded by 32-bits of zeros.
97 *
98 * L2TPv3 Session Header Over IP
99 *
100 * 0 1 2 3
101 * 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
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 * | Session ID |
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 * | Cookie (optional, maximum 64 bits)...
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * |
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 *
110 * L2TPv3 Control Message Header Over IP
111 *
112 * 0 1 2 3
113 * 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
114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
115 * | (32 bits of zeros) |
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
117 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * | Control Connection ID |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * | Ns | Nr |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 *
124 * All control frames are passed to userspace.
125 */
126static int l2tp_ip6_recv(struct sk_buff *skb)
127{
Shmulik Ladkani0e6b5252016-05-26 20:16:36 +0300128 struct net *net = dev_net(skb->dev);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000129 struct sock *sk;
130 u32 session_id;
131 u32 tunnel_id;
132 unsigned char *ptr, *optr;
133 struct l2tp_session *session;
134 struct l2tp_tunnel *tunnel = NULL;
Guillaume Nault8f7dc9a2017-11-03 16:49:00 +0100135 struct ipv6hdr *iph;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000136 int length;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000137
Chris Elstona32e0ee2012-04-29 21:48:54 +0000138 if (!pskb_may_pull(skb, 4))
139 goto discard;
140
Haishuang Yanbe447f32016-04-03 22:09:24 +0800141 /* Point to L2TP header */
142 optr = ptr = skb->data;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000143 session_id = ntohl(*((__be32 *) ptr));
144 ptr += 4;
145
146 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
147 * the session_id. If it is 0, the packet is a L2TP control
148 * frame and the session_id value can be discarded.
149 */
150 if (session_id == 0) {
151 __skb_pull(skb, 4);
152 goto pass_up;
153 }
154
155 /* Ok, this is a data packet. Lookup the session. */
Guillaume Nault01e28b92018-08-10 13:21:57 +0200156 session = l2tp_session_get(net, session_id);
Guillaume Nault61b9a042017-03-31 13:02:25 +0200157 if (!session)
Chris Elstona32e0ee2012-04-29 21:48:54 +0000158 goto discard;
159
160 tunnel = session->tunnel;
Guillaume Nault61b9a042017-03-31 13:02:25 +0200161 if (!tunnel)
162 goto discard_sess;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000163
164 /* Trace packet contents, if enabled */
165 if (tunnel->debug & L2TP_MSG_DATA) {
166 length = min(32u, skb->len);
167 if (!pskb_may_pull(skb, length))
Guillaume Nault61b9a042017-03-31 13:02:25 +0200168 goto discard_sess;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000169
Haishuang Yanbe447f32016-04-03 22:09:24 +0800170 /* Point to L2TP header */
171 optr = ptr = skb->data;
172 ptr += 4;
Joe Perchesa4ca44f2012-05-16 09:55:56 +0000173 pr_debug("%s: ip recv\n", tunnel->name);
174 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000175 }
176
Jacob Wen4522a702019-01-30 14:55:14 +0800177 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
178 goto discard_sess;
179
Guillaume Nault2b139e62018-07-25 14:53:33 +0200180 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
Guillaume Nault61b9a042017-03-31 13:02:25 +0200181 l2tp_session_dec_refcount(session);
182
Chris Elstona32e0ee2012-04-29 21:48:54 +0000183 return 0;
184
185pass_up:
186 /* Get the tunnel_id from the L2TP header */
187 if (!pskb_may_pull(skb, 12))
188 goto discard;
189
190 if ((skb->data[0] & 0xc0) != 0xc0)
191 goto discard;
192
193 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
Guillaume Nault8f7dc9a2017-11-03 16:49:00 +0100194 iph = ipv6_hdr(skb);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000195
Guillaume Nault8f7dc9a2017-11-03 16:49:00 +0100196 read_lock_bh(&l2tp_ip6_lock);
197 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
198 inet6_iif(skb), tunnel_id);
199 if (!sk) {
Chris Elstona32e0ee2012-04-29 21:48:54 +0000200 read_unlock_bh(&l2tp_ip6_lock);
Guillaume Nault8f7dc9a2017-11-03 16:49:00 +0100201 goto discard;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000202 }
Guillaume Nault8f7dc9a2017-11-03 16:49:00 +0100203 sock_hold(sk);
204 read_unlock_bh(&l2tp_ip6_lock);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000205
Chris Elstona32e0ee2012-04-29 21:48:54 +0000206 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
207 goto discard_put;
208
Florian Westphal895b5c92019-09-29 20:54:03 +0200209 nf_reset_ct(skb);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000210
211 return sk_receive_skb(sk, skb, 1);
212
Guillaume Nault61b9a042017-03-31 13:02:25 +0200213discard_sess:
Guillaume Nault61b9a042017-03-31 13:02:25 +0200214 l2tp_session_dec_refcount(session);
215 goto discard;
216
Chris Elstona32e0ee2012-04-29 21:48:54 +0000217discard_put:
218 sock_put(sk);
219
220discard:
221 kfree_skb(skb);
222 return 0;
223}
224
225static int l2tp_ip6_open(struct sock *sk)
226{
227 /* Prevent autobind. We don't have ports. */
228 inet_sk(sk)->inet_num = IPPROTO_L2TP;
229
230 write_lock_bh(&l2tp_ip6_lock);
231 sk_add_node(sk, &l2tp_ip6_table);
232 write_unlock_bh(&l2tp_ip6_lock);
233
234 return 0;
235}
236
237static void l2tp_ip6_close(struct sock *sk, long timeout)
238{
239 write_lock_bh(&l2tp_ip6_lock);
240 hlist_del_init(&sk->sk_bind_node);
241 sk_del_node_init(sk);
242 write_unlock_bh(&l2tp_ip6_lock);
243
244 sk_common_release(sk);
245}
246
247static void l2tp_ip6_destroy_sock(struct sock *sk)
248{
James Chapmand00fa9a2018-02-23 17:45:45 +0000249 struct l2tp_tunnel *tunnel = sk->sk_user_data;
Tom Parkin93606312013-03-19 06:11:15 +0000250
Chris Elstona32e0ee2012-04-29 21:48:54 +0000251 lock_sock(sk);
252 ip6_flush_pending_frames(sk);
253 release_sock(sk);
254
James Chapmand00fa9a2018-02-23 17:45:45 +0000255 if (tunnel)
256 l2tp_tunnel_delete(tunnel);
Tom Parkin93606312013-03-19 06:11:15 +0000257
Chris Elstona32e0ee2012-04-29 21:48:54 +0000258 inet6_destroy_sock(sk);
259}
260
261static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
262{
263 struct inet_sock *inet = inet_sk(sk);
264 struct ipv6_pinfo *np = inet6_sk(sk);
265 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
Shmulik Ladkani0e6b5252016-05-26 20:16:36 +0300266 struct net *net = sock_net(sk);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000267 __be32 v4addr = 0;
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100268 int bound_dev_if;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000269 int addr_type;
270 int err;
271
James Chapmanc51ce492012-05-29 03:30:42 +0000272 if (addr->l2tp_family != AF_INET6)
273 return -EINVAL;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000274 if (addr_len < sizeof(*addr))
275 return -EINVAL;
276
277 addr_type = ipv6_addr_type(&addr->l2tp_addr);
278
279 /* l2tp_ip6 sockets are IPv6 only */
280 if (addr_type == IPV6_ADDR_MAPPED)
281 return -EADDRNOTAVAIL;
282
283 /* L2TP is point-point, not multicast */
284 if (addr_type & IPV6_ADDR_MULTICAST)
285 return -EADDRNOTAVAIL;
286
Chris Elstona32e0ee2012-04-29 21:48:54 +0000287 lock_sock(sk);
288
289 err = -EINVAL;
Guillaume Nault32c23112016-11-18 22:13:00 +0100290 if (!sock_flag(sk, SOCK_ZAPPED))
291 goto out_unlock;
292
Chris Elstona32e0ee2012-04-29 21:48:54 +0000293 if (sk->sk_state != TCP_CLOSE)
294 goto out_unlock;
295
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100296 bound_dev_if = sk->sk_bound_dev_if;
297
Chris Elstona32e0ee2012-04-29 21:48:54 +0000298 /* Check if the address belongs to the host. */
299 rcu_read_lock();
300 if (addr_type != IPV6_ADDR_ANY) {
301 struct net_device *dev = NULL;
302
303 if (addr_type & IPV6_ADDR_LINKLOCAL) {
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100304 if (addr->l2tp_scope_id)
305 bound_dev_if = addr->l2tp_scope_id;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000306
307 /* Binding to link-local address requires an
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100308 * interface.
309 */
310 if (!bound_dev_if)
Chris Elstona32e0ee2012-04-29 21:48:54 +0000311 goto out_unlock_rcu;
312
313 err = -ENODEV;
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100314 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000315 if (!dev)
316 goto out_unlock_rcu;
317 }
318
319 /* ipv4 addr of the socket is invalid. Only the
320 * unspecified and mapped address have a v4 equivalent.
321 */
322 v4addr = LOOPBACK4_IPV6;
323 err = -EADDRNOTAVAIL;
324 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
325 goto out_unlock_rcu;
326 }
327 rcu_read_unlock();
328
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100329 write_lock_bh(&l2tp_ip6_lock);
Guillaume Naulta9b2dff2016-12-30 19:48:20 +0100330 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
Guillaume Naultd5e3a192016-11-29 13:09:46 +0100331 addr->l2tp_conn_id)) {
332 write_unlock_bh(&l2tp_ip6_lock);
333 err = -EADDRINUSE;
334 goto out_unlock;
335 }
336
337 inet->inet_saddr = v4addr;
338 inet->inet_rcv_saddr = v4addr;
339 sk->sk_bound_dev_if = bound_dev_if;
Eric Dumazetefe42082013-10-03 15:42:29 -0700340 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000341 np->saddr = addr->l2tp_addr;
342
343 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
344
Chris Elstona32e0ee2012-04-29 21:48:54 +0000345 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
346 sk_del_node_init(sk);
347 write_unlock_bh(&l2tp_ip6_lock);
348
James Chapmanc51ce492012-05-29 03:30:42 +0000349 sock_reset_flag(sk, SOCK_ZAPPED);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000350 release_sock(sk);
351 return 0;
352
353out_unlock_rcu:
354 rcu_read_unlock();
355out_unlock:
356 release_sock(sk);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000357
Chris Elstona32e0ee2012-04-29 21:48:54 +0000358 return err;
359}
360
361static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
362 int addr_len)
363{
364 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
365 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
366 struct in6_addr *daddr;
367 int addr_type;
368 int rc;
369
370 if (addr_len < sizeof(*lsa))
371 return -EINVAL;
372
Hannes Frederic Sowa82b276c2014-01-20 05:16:39 +0100373 if (usin->sin6_family != AF_INET6)
374 return -EINVAL;
375
Chris Elstona32e0ee2012-04-29 21:48:54 +0000376 addr_type = ipv6_addr_type(&usin->sin6_addr);
377 if (addr_type & IPV6_ADDR_MULTICAST)
378 return -EINVAL;
379
380 if (addr_type & IPV6_ADDR_MAPPED) {
381 daddr = &usin->sin6_addr;
382 if (ipv4_is_multicast(daddr->s6_addr32[3]))
383 return -EINVAL;
384 }
385
Chris Elstona32e0ee2012-04-29 21:48:54 +0000386 lock_sock(sk);
387
Guillaume Nault0382a252016-11-29 13:09:44 +0100388 /* Must bind first - autobinding does not work */
389 if (sock_flag(sk, SOCK_ZAPPED)) {
390 rc = -EINVAL;
391 goto out_sk;
392 }
393
394 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
395 if (rc < 0)
396 goto out_sk;
397
Chris Elstona32e0ee2012-04-29 21:48:54 +0000398 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
399
400 write_lock_bh(&l2tp_ip6_lock);
401 hlist_del_init(&sk->sk_bind_node);
402 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
403 write_unlock_bh(&l2tp_ip6_lock);
404
Guillaume Nault0382a252016-11-29 13:09:44 +0100405out_sk:
Chris Elstona32e0ee2012-04-29 21:48:54 +0000406 release_sock(sk);
407
408 return rc;
409}
410
James Chapmanc51ce492012-05-29 03:30:42 +0000411static int l2tp_ip6_disconnect(struct sock *sk, int flags)
412{
413 if (sock_flag(sk, SOCK_ZAPPED))
414 return 0;
415
Eric Dumazet286c72d2016-10-20 09:39:40 -0700416 return __udp_disconnect(sk, flags);
James Chapmanc51ce492012-05-29 03:30:42 +0000417}
418
Chris Elstona32e0ee2012-04-29 21:48:54 +0000419static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
Denys Vlasenko9b2c45d2018-02-12 20:00:20 +0100420 int peer)
Chris Elstona32e0ee2012-04-29 21:48:54 +0000421{
422 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
423 struct sock *sk = sock->sk;
424 struct ipv6_pinfo *np = inet6_sk(sk);
425 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
426
427 lsa->l2tp_family = AF_INET6;
428 lsa->l2tp_flowinfo = 0;
429 lsa->l2tp_scope_id = 0;
Mathias Krause04d4fbc2012-08-15 11:31:52 +0000430 lsa->l2tp_unused = 0;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000431 if (peer) {
432 if (!lsk->peer_conn_id)
433 return -ENOTCONN;
434 lsa->l2tp_conn_id = lsk->peer_conn_id;
Eric Dumazetefe42082013-10-03 15:42:29 -0700435 lsa->l2tp_addr = sk->sk_v6_daddr;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000436 if (np->sndflow)
437 lsa->l2tp_flowinfo = np->flow_label;
438 } else {
Eric Dumazetefe42082013-10-03 15:42:29 -0700439 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
Chris Elstona32e0ee2012-04-29 21:48:54 +0000440 lsa->l2tp_addr = np->saddr;
441 else
Eric Dumazetefe42082013-10-03 15:42:29 -0700442 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000443
444 lsa->l2tp_conn_id = lsk->conn_id;
445 }
446 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
447 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
Denys Vlasenko9b2c45d2018-02-12 20:00:20 +0100448 return sizeof(*lsa);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000449}
450
451static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
452{
453 int rc;
454
455 /* Charge it to the socket, dropping if the queue is full. */
456 rc = sock_queue_rcv_skb(sk, skb);
457 if (rc < 0)
458 goto drop;
459
460 return 0;
461
462drop:
Shmulik Ladkani0e6b5252016-05-26 20:16:36 +0300463 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000464 kfree_skb(skb);
465 return -1;
466}
467
468static int l2tp_ip6_push_pending_frames(struct sock *sk)
469{
470 struct sk_buff *skb;
471 __be32 *transhdr = NULL;
472 int err = 0;
473
474 skb = skb_peek(&sk->sk_write_queue);
475 if (skb == NULL)
476 goto out;
477
478 transhdr = (__be32 *)skb_transport_header(skb);
479 *transhdr = 0;
480
481 err = ip6_push_pending_frames(sk);
482
483out:
484 return err;
485}
486
487/* Userspace will call sendmsg() on the tunnel socket to send L2TP
488 * control frames.
489 */
Ying Xue1b784142015-03-02 15:37:48 +0800490static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
Chris Elstona32e0ee2012-04-29 21:48:54 +0000491{
492 struct ipv6_txoptions opt_space;
Steffen Hurrle342dfc32014-01-17 22:53:15 +0100493 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000494 struct in6_addr *daddr, *final_p, final;
495 struct ipv6_pinfo *np = inet6_sk(sk);
Eric Dumazet45f6fad2015-11-29 19:37:57 -0800496 struct ipv6_txoptions *opt_to_free = NULL;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000497 struct ipv6_txoptions *opt = NULL;
498 struct ip6_flowlabel *flowlabel = NULL;
499 struct dst_entry *dst = NULL;
500 struct flowi6 fl6;
Wei Wang26879da2016-05-02 21:40:07 -0700501 struct ipcm6_cookie ipc6;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000502 int addr_len = msg->msg_namelen;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000503 int transhdrlen = 4; /* zero session-id */
504 int ulen = len + transhdrlen;
505 int err;
506
507 /* Rough check on arithmetic overflow,
508 better check is made in ip6_append_data().
509 */
510 if (len > INT_MAX)
511 return -EMSGSIZE;
512
513 /* Mirror BSD error message compatibility */
514 if (msg->msg_flags & MSG_OOB)
515 return -EOPNOTSUPP;
516
517 /*
518 * Get and verify the address.
519 */
520 memset(&fl6, 0, sizeof(fl6));
521
522 fl6.flowi6_mark = sk->sk_mark;
Lorenzo Colittie2d118a2016-11-04 02:23:43 +0900523 fl6.flowi6_uid = sk->sk_uid;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000524
Willem de Bruijnb515430a2018-07-06 10:12:55 -0400525 ipcm6_init(&ipc6);
Wei Wang26879da2016-05-02 21:40:07 -0700526
Chris Elstona32e0ee2012-04-29 21:48:54 +0000527 if (lsa) {
528 if (addr_len < SIN6_LEN_RFC2133)
529 return -EINVAL;
530
531 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
532 return -EAFNOSUPPORT;
533
534 daddr = &lsa->l2tp_addr;
535 if (np->sndflow) {
536 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
537 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
538 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
Willem de Bruijn59c820b2019-07-07 05:34:45 -0400539 if (IS_ERR(flowlabel))
Chris Elstona32e0ee2012-04-29 21:48:54 +0000540 return -EINVAL;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000541 }
542 }
543
544 /*
545 * Otherwise it will be difficult to maintain
546 * sk->sk_dst_cache.
547 */
548 if (sk->sk_state == TCP_ESTABLISHED &&
Eric Dumazetefe42082013-10-03 15:42:29 -0700549 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
550 daddr = &sk->sk_v6_daddr;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000551
552 if (addr_len >= sizeof(struct sockaddr_in6) &&
553 lsa->l2tp_scope_id &&
554 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
555 fl6.flowi6_oif = lsa->l2tp_scope_id;
556 } else {
557 if (sk->sk_state != TCP_ESTABLISHED)
558 return -EDESTADDRREQ;
559
Eric Dumazetefe42082013-10-03 15:42:29 -0700560 daddr = &sk->sk_v6_daddr;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000561 fl6.flowlabel = np->flow_label;
562 }
563
564 if (fl6.flowi6_oif == 0)
565 fl6.flowi6_oif = sk->sk_bound_dev_if;
566
567 if (msg->msg_controllen) {
568 opt = &opt_space;
569 memset(opt, 0, sizeof(struct ipv6_txoptions));
570 opt->tot_len = sizeof(struct ipv6_txoptions);
Wei Wang26879da2016-05-02 21:40:07 -0700571 ipc6.opt = opt;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000572
Willem de Bruijn5fdaa882018-07-06 10:12:57 -0400573 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
Wei Wang26879da2016-05-02 21:40:07 -0700574 if (err < 0) {
Chris Elstona32e0ee2012-04-29 21:48:54 +0000575 fl6_sock_release(flowlabel);
576 return err;
577 }
578 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
579 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
Willem de Bruijn59c820b2019-07-07 05:34:45 -0400580 if (IS_ERR(flowlabel))
Chris Elstona32e0ee2012-04-29 21:48:54 +0000581 return -EINVAL;
582 }
583 if (!(opt->opt_nflen|opt->opt_flen))
584 opt = NULL;
585 }
586
Eric Dumazet45f6fad2015-11-29 19:37:57 -0800587 if (!opt) {
588 opt = txopt_get(np);
589 opt_to_free = opt;
590 }
Chris Elstona32e0ee2012-04-29 21:48:54 +0000591 if (flowlabel)
592 opt = fl6_merge_options(&opt_space, flowlabel, opt);
593 opt = ipv6_fixup_options(&opt_space, opt);
Wei Wang26879da2016-05-02 21:40:07 -0700594 ipc6.opt = opt;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000595
596 fl6.flowi6_proto = sk->sk_protocol;
597 if (!ipv6_addr_any(daddr))
598 fl6.daddr = *daddr;
599 else
600 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
601 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
602 fl6.saddr = np->saddr;
603
604 final_p = fl6_update_dst(&fl6, opt, &final);
605
606 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
607 fl6.flowi6_oif = np->mcast_oif;
608 else if (!fl6.flowi6_oif)
609 fl6.flowi6_oif = np->ucast_oif;
610
611 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
612
Hannes Frederic Sowa38b70972016-06-11 20:08:19 +0200613 if (ipc6.tclass < 0)
614 ipc6.tclass = np->tclass;
615
616 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
617
Sabrina Dubrocac4e85f72019-12-04 15:35:52 +0100618 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000619 if (IS_ERR(dst)) {
620 err = PTR_ERR(dst);
621 goto out;
622 }
623
Wei Wang26879da2016-05-02 21:40:07 -0700624 if (ipc6.hlimit < 0)
625 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000626
Wei Wang26879da2016-05-02 21:40:07 -0700627 if (ipc6.dontfrag < 0)
628 ipc6.dontfrag = np->dontfrag;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000629
630 if (msg->msg_flags & MSG_CONFIRM)
631 goto do_confirm;
632
633back_from_confirm:
634 lock_sock(sk);
Al Virof69e6d12014-11-24 13:23:40 -0500635 err = ip6_append_data(sk, ip_generic_getfrag, msg,
Wei Wang26879da2016-05-02 21:40:07 -0700636 ulen, transhdrlen, &ipc6,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000637 &fl6, (struct rt6_info *)dst,
Willem de Bruijn5fdaa882018-07-06 10:12:57 -0400638 msg->msg_flags);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000639 if (err)
640 ip6_flush_pending_frames(sk);
641 else if (!(msg->msg_flags & MSG_MORE))
642 err = l2tp_ip6_push_pending_frames(sk);
643 release_sock(sk);
644done:
645 dst_release(dst);
646out:
647 fl6_sock_release(flowlabel);
Eric Dumazet45f6fad2015-11-29 19:37:57 -0800648 txopt_put(opt_to_free);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000649
650 return err < 0 ? err : len;
651
652do_confirm:
Julian Anastasov0dec8792017-02-06 23:14:16 +0200653 if (msg->msg_flags & MSG_PROBE)
654 dst_confirm_neigh(dst, &fl6.daddr);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000655 if (!(msg->msg_flags & MSG_PROBE) || len)
656 goto back_from_confirm;
657 err = 0;
658 goto done;
659}
660
Ying Xue1b784142015-03-02 15:37:48 +0800661static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
662 int noblock, int flags, int *addr_len)
Chris Elstona32e0ee2012-04-29 21:48:54 +0000663{
Tom Parkin700163d2013-01-31 01:02:26 +0000664 struct ipv6_pinfo *np = inet6_sk(sk);
Steffen Hurrle342dfc32014-01-17 22:53:15 +0100665 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000666 size_t copied = 0;
667 int err = -EOPNOTSUPP;
668 struct sk_buff *skb;
669
670 if (flags & MSG_OOB)
671 goto out;
672
Chris Elstona32e0ee2012-04-29 21:48:54 +0000673 if (flags & MSG_ERRQUEUE)
Hannes Frederic Sowa85fbaa72013-11-23 00:46:12 +0100674 return ipv6_recv_error(sk, msg, len, addr_len);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000675
676 skb = skb_recv_datagram(sk, flags, noblock, &err);
677 if (!skb)
678 goto out;
679
680 copied = skb->len;
681 if (len < copied) {
682 msg->msg_flags |= MSG_TRUNC;
683 copied = len;
684 }
685
David S. Miller51f3d022014-11-05 16:46:40 -0500686 err = skb_copy_datagram_msg(skb, 0, msg, copied);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000687 if (err)
688 goto done;
689
690 sock_recv_timestamp(msg, sk, skb);
691
692 /* Copy the address. */
693 if (lsa) {
694 lsa->l2tp_family = AF_INET6;
695 lsa->l2tp_unused = 0;
696 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
697 lsa->l2tp_flowinfo = 0;
698 lsa->l2tp_scope_id = 0;
Mathias Krauseb860d3c2013-04-07 01:51:55 +0000699 lsa->l2tp_conn_id = 0;
Chris Elstona32e0ee2012-04-29 21:48:54 +0000700 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
Duan Jiong43304872014-08-01 09:52:58 +0800701 lsa->l2tp_scope_id = inet6_iif(skb);
Eric Dumazet163d1c32019-03-12 06:50:11 -0700702 *addr_len = sizeof(*lsa);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000703 }
704
Tom Parkin700163d2013-01-31 01:02:26 +0000705 if (np->rxopt.all)
706 ip6_datagram_recv_ctl(sk, msg, skb);
Chris Elstona32e0ee2012-04-29 21:48:54 +0000707
708 if (flags & MSG_TRUNC)
709 copied = skb->len;
710done:
711 skb_free_datagram(sk, skb);
712out:
713 return err ? err : copied;
714}
715
716static struct proto l2tp_ip6_prot = {
717 .name = "L2TP/IPv6",
718 .owner = THIS_MODULE,
719 .init = l2tp_ip6_open,
720 .close = l2tp_ip6_close,
721 .bind = l2tp_ip6_bind,
722 .connect = l2tp_ip6_connect,
James Chapmanc51ce492012-05-29 03:30:42 +0000723 .disconnect = l2tp_ip6_disconnect,
Eric Dumazet72fb96e72017-02-09 16:15:52 -0800724 .ioctl = l2tp_ioctl,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000725 .destroy = l2tp_ip6_destroy_sock,
726 .setsockopt = ipv6_setsockopt,
727 .getsockopt = ipv6_getsockopt,
728 .sendmsg = l2tp_ip6_sendmsg,
729 .recvmsg = l2tp_ip6_recvmsg,
730 .backlog_rcv = l2tp_ip6_backlog_recv,
Craig Gallek496611d2016-02-10 11:50:36 -0500731 .hash = inet6_hash,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000732 .unhash = inet_unhash,
733 .obj_size = sizeof(struct l2tp_ip6_sock),
734#ifdef CONFIG_COMPAT
735 .compat_setsockopt = compat_ipv6_setsockopt,
736 .compat_getsockopt = compat_ipv6_getsockopt,
737#endif
738};
739
740static const struct proto_ops l2tp_ip6_ops = {
741 .family = PF_INET6,
742 .owner = THIS_MODULE,
743 .release = inet6_release,
744 .bind = inet6_bind,
745 .connect = inet_dgram_connect,
746 .socketpair = sock_no_socketpair,
747 .accept = sock_no_accept,
748 .getname = l2tp_ip6_getname,
Linus Torvaldsa11e1d42018-06-28 09:43:44 -0700749 .poll = datagram_poll,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000750 .ioctl = inet6_ioctl,
Arnd Bergmannc7cbdbf2019-04-17 22:51:48 +0200751 .gettstamp = sock_gettstamp,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000752 .listen = sock_no_listen,
753 .shutdown = inet_shutdown,
754 .setsockopt = sock_common_setsockopt,
755 .getsockopt = sock_common_getsockopt,
756 .sendmsg = inet_sendmsg,
757 .recvmsg = sock_common_recvmsg,
758 .mmap = sock_no_mmap,
759 .sendpage = sock_no_sendpage,
760#ifdef CONFIG_COMPAT
761 .compat_setsockopt = compat_sock_common_setsockopt,
762 .compat_getsockopt = compat_sock_common_getsockopt,
763#endif
764};
765
766static struct inet_protosw l2tp_ip6_protosw = {
767 .type = SOCK_DGRAM,
768 .protocol = IPPROTO_L2TP,
769 .prot = &l2tp_ip6_prot,
770 .ops = &l2tp_ip6_ops,
Chris Elstona32e0ee2012-04-29 21:48:54 +0000771};
772
773static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
774 .handler = l2tp_ip6_recv,
775};
776
777static int __init l2tp_ip6_init(void)
778{
779 int err;
780
Joe Perchesa4ca44f2012-05-16 09:55:56 +0000781 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
Chris Elstona32e0ee2012-04-29 21:48:54 +0000782
783 err = proto_register(&l2tp_ip6_prot, 1);
784 if (err != 0)
785 goto out;
786
787 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
788 if (err)
789 goto out1;
790
791 inet6_register_protosw(&l2tp_ip6_protosw);
792 return 0;
793
794out1:
795 proto_unregister(&l2tp_ip6_prot);
796out:
797 return err;
798}
799
800static void __exit l2tp_ip6_exit(void)
801{
802 inet6_unregister_protosw(&l2tp_ip6_protosw);
803 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
804 proto_unregister(&l2tp_ip6_prot);
805}
806
807module_init(l2tp_ip6_init);
808module_exit(l2tp_ip6_exit);
809
810MODULE_LICENSE("GPL");
811MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
812MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
813MODULE_VERSION("1.0");
814
815/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
816 * enums
817 */
818MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
stephen hemminger163c2e22015-09-23 21:33:35 -0700819MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);