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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
20dcb110 | 2 | /* L2TPv3 IP encapsulation support for IPv6 |
a32e0eec CE |
3 | * |
4 | * Copyright (c) 2012 Katalix Systems Ltd | |
a32e0eec CE |
5 | */ |
6 | ||
a4ca44fa JP |
7 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
8 | ||
a32e0eec CE |
9 | #include <linux/icmp.h> |
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/random.h> | |
13 | #include <linux/socket.h> | |
14 | #include <linux/l2tp.h> | |
15 | #include <linux/in.h> | |
16 | #include <linux/in6.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> | |
a32e0eec CE |
22 | #include <net/tcp_states.h> |
23 | #include <net/protocol.h> | |
24 | #include <net/xfrm.h> | |
25 | ||
26 | #include <net/transp_v6.h> | |
27 | #include <net/addrconf.h> | |
28 | #include <net/ip6_route.h> | |
29 | ||
30 | #include "l2tp_core.h" | |
31 | ||
32 | struct l2tp_ip6_sock { | |
33 | /* inet_sock has to be the first member of l2tp_ip6_sock */ | |
34 | struct inet_sock inet; | |
35 | ||
36 | u32 conn_id; | |
37 | u32 peer_conn_id; | |
38 | ||
39 | /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see | |
20dcb110 TP |
40 | * inet6_sk_generic |
41 | */ | |
a32e0eec CE |
42 | struct ipv6_pinfo inet6; |
43 | }; | |
44 | ||
45 | static DEFINE_RWLOCK(l2tp_ip6_lock); | |
46 | static struct hlist_head l2tp_ip6_table; | |
47 | static struct hlist_head l2tp_ip6_bind_table; | |
48 | ||
49 | static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) | |
50 | { | |
51 | return (struct l2tp_ip6_sock *)sk; | |
52 | } | |
53 | ||
bb39b0bd GN |
54 | static struct sock *__l2tp_ip6_bind_lookup(const struct net *net, |
55 | const struct in6_addr *laddr, | |
a9b2dff8 | 56 | const struct in6_addr *raddr, |
a32e0eec CE |
57 | int dif, u32 tunnel_id) |
58 | { | |
a32e0eec CE |
59 | struct sock *sk; |
60 | ||
b67bfe0d | 61 | sk_for_each_bound(sk, &l2tp_ip6_bind_table) { |
97b84fd6 | 62 | const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk); |
a9b2dff8 | 63 | const struct in6_addr *sk_raddr = &sk->sk_v6_daddr; |
bb39b0bd | 64 | const struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); |
ff009403 | 65 | int bound_dev_if; |
a32e0eec | 66 | |
c5fdae04 GN |
67 | if (!net_eq(sock_net(sk), net)) |
68 | continue; | |
69 | ||
ff009403 ED |
70 | bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); |
71 | if (bound_dev_if && dif && bound_dev_if != dif) | |
c5fdae04 GN |
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; | |
a32e0eec CE |
86 | } |
87 | ||
88 | sk = NULL; | |
89 | found: | |
90 | return sk; | |
91 | } | |
92 | ||
a32e0eec CE |
93 | /* 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 | */ | |
126 | static int l2tp_ip6_recv(struct sk_buff *skb) | |
127 | { | |
0e6b5259 | 128 | struct net *net = dev_net(skb->dev); |
a32e0eec CE |
129 | 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; | |
8f7dc9ae | 135 | struct ipv6hdr *iph; |
a32e0eec | 136 | |
a32e0eec CE |
137 | if (!pskb_may_pull(skb, 4)) |
138 | goto discard; | |
139 | ||
be447f30 | 140 | /* Point to L2TP header */ |
95075150 TP |
141 | optr = skb->data; |
142 | ptr = skb->data; | |
b71a61cc | 143 | session_id = ntohl(*((__be32 *)ptr)); |
a32e0eec CE |
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. */ | |
01e28b92 | 156 | session = l2tp_session_get(net, session_id); |
61b9a047 | 157 | if (!session) |
a32e0eec CE |
158 | goto discard; |
159 | ||
160 | tunnel = session->tunnel; | |
61b9a047 GN |
161 | if (!tunnel) |
162 | goto discard_sess; | |
a32e0eec | 163 | |
4522a70d JW |
164 | if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) |
165 | goto discard_sess; | |
166 | ||
2b139e6b | 167 | l2tp_recv_common(session, skb, ptr, optr, 0, skb->len); |
61b9a047 GN |
168 | l2tp_session_dec_refcount(session); |
169 | ||
a32e0eec CE |
170 | return 0; |
171 | ||
172 | pass_up: | |
173 | /* Get the tunnel_id from the L2TP header */ | |
174 | if (!pskb_may_pull(skb, 12)) | |
175 | goto discard; | |
176 | ||
177 | if ((skb->data[0] & 0xc0) != 0xc0) | |
178 | goto discard; | |
179 | ||
b71a61cc | 180 | tunnel_id = ntohl(*(__be32 *)&skb->data[4]); |
8f7dc9ae GN |
181 | iph = ipv6_hdr(skb); |
182 | ||
183 | read_lock_bh(&l2tp_ip6_lock); | |
184 | sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr, | |
185 | inet6_iif(skb), tunnel_id); | |
186 | if (!sk) { | |
a32e0eec | 187 | read_unlock_bh(&l2tp_ip6_lock); |
8f7dc9ae | 188 | goto discard; |
a32e0eec | 189 | } |
8f7dc9ae GN |
190 | sock_hold(sk); |
191 | read_unlock_bh(&l2tp_ip6_lock); | |
a32e0eec | 192 | |
a32e0eec CE |
193 | if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) |
194 | goto discard_put; | |
195 | ||
895b5c9f | 196 | nf_reset_ct(skb); |
a32e0eec CE |
197 | |
198 | return sk_receive_skb(sk, skb, 1); | |
199 | ||
61b9a047 | 200 | discard_sess: |
61b9a047 GN |
201 | l2tp_session_dec_refcount(session); |
202 | goto discard; | |
203 | ||
a32e0eec CE |
204 | discard_put: |
205 | sock_put(sk); | |
206 | ||
207 | discard: | |
208 | kfree_skb(skb); | |
209 | return 0; | |
210 | } | |
211 | ||
02c71b14 | 212 | static int l2tp_ip6_hash(struct sock *sk) |
a32e0eec | 213 | { |
02c71b14 ED |
214 | if (sk_unhashed(sk)) { |
215 | write_lock_bh(&l2tp_ip6_lock); | |
216 | sk_add_node(sk, &l2tp_ip6_table); | |
217 | write_unlock_bh(&l2tp_ip6_lock); | |
218 | } | |
219 | return 0; | |
220 | } | |
a32e0eec | 221 | |
02c71b14 ED |
222 | static void l2tp_ip6_unhash(struct sock *sk) |
223 | { | |
224 | if (sk_unhashed(sk)) | |
225 | return; | |
a32e0eec | 226 | write_lock_bh(&l2tp_ip6_lock); |
02c71b14 | 227 | sk_del_node_init(sk); |
a32e0eec | 228 | write_unlock_bh(&l2tp_ip6_lock); |
02c71b14 ED |
229 | } |
230 | ||
231 | static int l2tp_ip6_open(struct sock *sk) | |
232 | { | |
233 | /* Prevent autobind. We don't have ports. */ | |
234 | inet_sk(sk)->inet_num = IPPROTO_L2TP; | |
a32e0eec | 235 | |
02c71b14 | 236 | l2tp_ip6_hash(sk); |
a32e0eec CE |
237 | return 0; |
238 | } | |
239 | ||
240 | static void l2tp_ip6_close(struct sock *sk, long timeout) | |
241 | { | |
242 | write_lock_bh(&l2tp_ip6_lock); | |
243 | hlist_del_init(&sk->sk_bind_node); | |
244 | sk_del_node_init(sk); | |
245 | write_unlock_bh(&l2tp_ip6_lock); | |
246 | ||
247 | sk_common_release(sk); | |
248 | } | |
249 | ||
250 | static void l2tp_ip6_destroy_sock(struct sock *sk) | |
251 | { | |
45faeff1 | 252 | struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk); |
93606317 | 253 | |
a32e0eec CE |
254 | lock_sock(sk); |
255 | ip6_flush_pending_frames(sk); | |
256 | release_sock(sk); | |
257 | ||
d00fa9ad JC |
258 | if (tunnel) |
259 | l2tp_tunnel_delete(tunnel); | |
93606317 | 260 | |
a32e0eec CE |
261 | inet6_destroy_sock(sk); |
262 | } | |
263 | ||
264 | static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) | |
265 | { | |
266 | struct inet_sock *inet = inet_sk(sk); | |
267 | struct ipv6_pinfo *np = inet6_sk(sk); | |
b71a61cc | 268 | struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *)uaddr; |
0e6b5259 | 269 | struct net *net = sock_net(sk); |
a32e0eec | 270 | __be32 v4addr = 0; |
d5e3a190 | 271 | int bound_dev_if; |
a32e0eec CE |
272 | int addr_type; |
273 | int err; | |
274 | ||
c51ce497 JC |
275 | if (addr->l2tp_family != AF_INET6) |
276 | return -EINVAL; | |
a32e0eec CE |
277 | if (addr_len < sizeof(*addr)) |
278 | return -EINVAL; | |
279 | ||
280 | addr_type = ipv6_addr_type(&addr->l2tp_addr); | |
281 | ||
282 | /* l2tp_ip6 sockets are IPv6 only */ | |
283 | if (addr_type == IPV6_ADDR_MAPPED) | |
284 | return -EADDRNOTAVAIL; | |
285 | ||
286 | /* L2TP is point-point, not multicast */ | |
287 | if (addr_type & IPV6_ADDR_MULTICAST) | |
288 | return -EADDRNOTAVAIL; | |
289 | ||
a32e0eec CE |
290 | lock_sock(sk); |
291 | ||
292 | err = -EINVAL; | |
32c23116 GN |
293 | if (!sock_flag(sk, SOCK_ZAPPED)) |
294 | goto out_unlock; | |
295 | ||
a32e0eec CE |
296 | if (sk->sk_state != TCP_CLOSE) |
297 | goto out_unlock; | |
298 | ||
d5e3a190 GN |
299 | bound_dev_if = sk->sk_bound_dev_if; |
300 | ||
a32e0eec CE |
301 | /* Check if the address belongs to the host. */ |
302 | rcu_read_lock(); | |
303 | if (addr_type != IPV6_ADDR_ANY) { | |
304 | struct net_device *dev = NULL; | |
305 | ||
306 | if (addr_type & IPV6_ADDR_LINKLOCAL) { | |
d5e3a190 GN |
307 | if (addr->l2tp_scope_id) |
308 | bound_dev_if = addr->l2tp_scope_id; | |
a32e0eec CE |
309 | |
310 | /* Binding to link-local address requires an | |
d5e3a190 GN |
311 | * interface. |
312 | */ | |
313 | if (!bound_dev_if) | |
a32e0eec CE |
314 | goto out_unlock_rcu; |
315 | ||
316 | err = -ENODEV; | |
d5e3a190 | 317 | dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if); |
a32e0eec CE |
318 | if (!dev) |
319 | goto out_unlock_rcu; | |
320 | } | |
321 | ||
322 | /* ipv4 addr of the socket is invalid. Only the | |
323 | * unspecified and mapped address have a v4 equivalent. | |
324 | */ | |
325 | v4addr = LOOPBACK4_IPV6; | |
326 | err = -EADDRNOTAVAIL; | |
327 | if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) | |
328 | goto out_unlock_rcu; | |
329 | } | |
330 | rcu_read_unlock(); | |
331 | ||
d5e3a190 | 332 | write_lock_bh(&l2tp_ip6_lock); |
a9b2dff8 | 333 | if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if, |
d5e3a190 GN |
334 | addr->l2tp_conn_id)) { |
335 | write_unlock_bh(&l2tp_ip6_lock); | |
336 | err = -EADDRINUSE; | |
337 | goto out_unlock; | |
338 | } | |
339 | ||
340 | inet->inet_saddr = v4addr; | |
341 | inet->inet_rcv_saddr = v4addr; | |
342 | sk->sk_bound_dev_if = bound_dev_if; | |
efe4208f | 343 | sk->sk_v6_rcv_saddr = addr->l2tp_addr; |
a32e0eec CE |
344 | np->saddr = addr->l2tp_addr; |
345 | ||
346 | l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; | |
347 | ||
a32e0eec CE |
348 | sk_add_bind_node(sk, &l2tp_ip6_bind_table); |
349 | sk_del_node_init(sk); | |
350 | write_unlock_bh(&l2tp_ip6_lock); | |
351 | ||
c51ce497 | 352 | sock_reset_flag(sk, SOCK_ZAPPED); |
a32e0eec CE |
353 | release_sock(sk); |
354 | return 0; | |
355 | ||
356 | out_unlock_rcu: | |
357 | rcu_read_unlock(); | |
358 | out_unlock: | |
359 | release_sock(sk); | |
a32e0eec | 360 | |
a32e0eec CE |
361 | return err; |
362 | } | |
363 | ||
364 | static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, | |
365 | int addr_len) | |
366 | { | |
b71a61cc TP |
367 | struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; |
368 | struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr; | |
a32e0eec CE |
369 | struct in6_addr *daddr; |
370 | int addr_type; | |
371 | int rc; | |
372 | ||
373 | if (addr_len < sizeof(*lsa)) | |
374 | return -EINVAL; | |
375 | ||
82b276cd HFS |
376 | if (usin->sin6_family != AF_INET6) |
377 | return -EINVAL; | |
378 | ||
a32e0eec CE |
379 | addr_type = ipv6_addr_type(&usin->sin6_addr); |
380 | if (addr_type & IPV6_ADDR_MULTICAST) | |
381 | return -EINVAL; | |
382 | ||
383 | if (addr_type & IPV6_ADDR_MAPPED) { | |
384 | daddr = &usin->sin6_addr; | |
385 | if (ipv4_is_multicast(daddr->s6_addr32[3])) | |
386 | return -EINVAL; | |
387 | } | |
388 | ||
a32e0eec CE |
389 | lock_sock(sk); |
390 | ||
0382a25a GN |
391 | /* Must bind first - autobinding does not work */ |
392 | if (sock_flag(sk, SOCK_ZAPPED)) { | |
393 | rc = -EINVAL; | |
394 | goto out_sk; | |
395 | } | |
396 | ||
397 | rc = __ip6_datagram_connect(sk, uaddr, addr_len); | |
398 | if (rc < 0) | |
399 | goto out_sk; | |
400 | ||
a32e0eec CE |
401 | l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; |
402 | ||
403 | write_lock_bh(&l2tp_ip6_lock); | |
404 | hlist_del_init(&sk->sk_bind_node); | |
405 | sk_add_bind_node(sk, &l2tp_ip6_bind_table); | |
406 | write_unlock_bh(&l2tp_ip6_lock); | |
407 | ||
0382a25a | 408 | out_sk: |
a32e0eec CE |
409 | release_sock(sk); |
410 | ||
411 | return rc; | |
412 | } | |
413 | ||
c51ce497 JC |
414 | static int l2tp_ip6_disconnect(struct sock *sk, int flags) |
415 | { | |
416 | if (sock_flag(sk, SOCK_ZAPPED)) | |
417 | return 0; | |
418 | ||
286c72de | 419 | return __udp_disconnect(sk, flags); |
c51ce497 JC |
420 | } |
421 | ||
a32e0eec | 422 | static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, |
9b2c45d4 | 423 | int peer) |
a32e0eec CE |
424 | { |
425 | struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; | |
426 | struct sock *sk = sock->sk; | |
427 | struct ipv6_pinfo *np = inet6_sk(sk); | |
428 | struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); | |
429 | ||
430 | lsa->l2tp_family = AF_INET6; | |
431 | lsa->l2tp_flowinfo = 0; | |
432 | lsa->l2tp_scope_id = 0; | |
04d4fbca | 433 | lsa->l2tp_unused = 0; |
a32e0eec CE |
434 | if (peer) { |
435 | if (!lsk->peer_conn_id) | |
436 | return -ENOTCONN; | |
437 | lsa->l2tp_conn_id = lsk->peer_conn_id; | |
efe4208f | 438 | lsa->l2tp_addr = sk->sk_v6_daddr; |
a32e0eec CE |
439 | if (np->sndflow) |
440 | lsa->l2tp_flowinfo = np->flow_label; | |
441 | } else { | |
efe4208f | 442 | if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) |
a32e0eec CE |
443 | lsa->l2tp_addr = np->saddr; |
444 | else | |
efe4208f | 445 | lsa->l2tp_addr = sk->sk_v6_rcv_saddr; |
a32e0eec CE |
446 | |
447 | lsa->l2tp_conn_id = lsk->conn_id; | |
448 | } | |
449 | if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) | |
ff009403 | 450 | lsa->l2tp_scope_id = READ_ONCE(sk->sk_bound_dev_if); |
9b2c45d4 | 451 | return sizeof(*lsa); |
a32e0eec CE |
452 | } |
453 | ||
454 | static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) | |
455 | { | |
456 | int rc; | |
457 | ||
458 | /* Charge it to the socket, dropping if the queue is full. */ | |
459 | rc = sock_queue_rcv_skb(sk, skb); | |
460 | if (rc < 0) | |
461 | goto drop; | |
462 | ||
463 | return 0; | |
464 | ||
465 | drop: | |
0e6b5259 | 466 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); |
a32e0eec CE |
467 | kfree_skb(skb); |
468 | return -1; | |
469 | } | |
470 | ||
471 | static int l2tp_ip6_push_pending_frames(struct sock *sk) | |
472 | { | |
473 | struct sk_buff *skb; | |
474 | __be32 *transhdr = NULL; | |
475 | int err = 0; | |
476 | ||
477 | skb = skb_peek(&sk->sk_write_queue); | |
0febc7b3 | 478 | if (!skb) |
a32e0eec CE |
479 | goto out; |
480 | ||
481 | transhdr = (__be32 *)skb_transport_header(skb); | |
482 | *transhdr = 0; | |
483 | ||
484 | err = ip6_push_pending_frames(sk); | |
485 | ||
486 | out: | |
487 | return err; | |
488 | } | |
489 | ||
490 | /* Userspace will call sendmsg() on the tunnel socket to send L2TP | |
491 | * control frames. | |
492 | */ | |
1b784140 | 493 | static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) |
a32e0eec CE |
494 | { |
495 | struct ipv6_txoptions opt_space; | |
342dfc30 | 496 | DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); |
a32e0eec CE |
497 | struct in6_addr *daddr, *final_p, final; |
498 | struct ipv6_pinfo *np = inet6_sk(sk); | |
45f6fad8 | 499 | struct ipv6_txoptions *opt_to_free = NULL; |
a32e0eec CE |
500 | struct ipv6_txoptions *opt = NULL; |
501 | struct ip6_flowlabel *flowlabel = NULL; | |
502 | struct dst_entry *dst = NULL; | |
503 | struct flowi6 fl6; | |
26879da5 | 504 | struct ipcm6_cookie ipc6; |
a32e0eec | 505 | int addr_len = msg->msg_namelen; |
a32e0eec | 506 | int transhdrlen = 4; /* zero session-id */ |
f638a84a | 507 | int ulen; |
a32e0eec CE |
508 | int err; |
509 | ||
510 | /* Rough check on arithmetic overflow, | |
20dcb110 | 511 | * better check is made in ip6_append_data(). |
a32e0eec | 512 | */ |
f638a84a | 513 | if (len > INT_MAX - transhdrlen) |
a32e0eec | 514 | return -EMSGSIZE; |
f638a84a | 515 | ulen = len + transhdrlen; |
a32e0eec CE |
516 | |
517 | /* Mirror BSD error message compatibility */ | |
518 | if (msg->msg_flags & MSG_OOB) | |
519 | return -EOPNOTSUPP; | |
520 | ||
20dcb110 | 521 | /* Get and verify the address */ |
a32e0eec CE |
522 | memset(&fl6, 0, sizeof(fl6)); |
523 | ||
524 | fl6.flowi6_mark = sk->sk_mark; | |
e2d118a1 | 525 | fl6.flowi6_uid = sk->sk_uid; |
a32e0eec | 526 | |
b515430a | 527 | ipcm6_init(&ipc6); |
26879da5 | 528 | |
a32e0eec CE |
529 | if (lsa) { |
530 | if (addr_len < SIN6_LEN_RFC2133) | |
531 | return -EINVAL; | |
532 | ||
533 | if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) | |
534 | return -EAFNOSUPPORT; | |
535 | ||
536 | daddr = &lsa->l2tp_addr; | |
537 | if (np->sndflow) { | |
538 | fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; | |
b71a61cc | 539 | if (fl6.flowlabel & IPV6_FLOWLABEL_MASK) { |
a32e0eec | 540 | flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); |
59c820b2 | 541 | if (IS_ERR(flowlabel)) |
a32e0eec | 542 | return -EINVAL; |
a32e0eec CE |
543 | } |
544 | } | |
545 | ||
20dcb110 | 546 | /* Otherwise it will be difficult to maintain |
a32e0eec CE |
547 | * sk->sk_dst_cache. |
548 | */ | |
549 | if (sk->sk_state == TCP_ESTABLISHED && | |
efe4208f ED |
550 | ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) |
551 | daddr = &sk->sk_v6_daddr; | |
a32e0eec CE |
552 | |
553 | if (addr_len >= sizeof(struct sockaddr_in6) && | |
554 | lsa->l2tp_scope_id && | |
555 | ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) | |
556 | fl6.flowi6_oif = lsa->l2tp_scope_id; | |
557 | } else { | |
558 | if (sk->sk_state != TCP_ESTABLISHED) | |
559 | return -EDESTADDRREQ; | |
560 | ||
efe4208f | 561 | daddr = &sk->sk_v6_daddr; |
a32e0eec CE |
562 | fl6.flowlabel = np->flow_label; |
563 | } | |
564 | ||
565 | if (fl6.flowi6_oif == 0) | |
ff009403 | 566 | fl6.flowi6_oif = READ_ONCE(sk->sk_bound_dev_if); |
a32e0eec CE |
567 | |
568 | if (msg->msg_controllen) { | |
569 | opt = &opt_space; | |
570 | memset(opt, 0, sizeof(struct ipv6_txoptions)); | |
571 | opt->tot_len = sizeof(struct ipv6_txoptions); | |
26879da5 | 572 | ipc6.opt = opt; |
a32e0eec | 573 | |
5fdaa88d | 574 | err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6); |
26879da5 | 575 | if (err < 0) { |
a32e0eec CE |
576 | fl6_sock_release(flowlabel); |
577 | return err; | |
578 | } | |
579 | if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { | |
580 | flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); | |
59c820b2 | 581 | if (IS_ERR(flowlabel)) |
a32e0eec CE |
582 | return -EINVAL; |
583 | } | |
b71a61cc | 584 | if (!(opt->opt_nflen | opt->opt_flen)) |
a32e0eec CE |
585 | opt = NULL; |
586 | } | |
587 | ||
45f6fad8 ED |
588 | if (!opt) { |
589 | opt = txopt_get(np); | |
590 | opt_to_free = opt; | |
591 | } | |
a32e0eec CE |
592 | if (flowlabel) |
593 | opt = fl6_merge_options(&opt_space, flowlabel, opt); | |
594 | opt = ipv6_fixup_options(&opt_space, opt); | |
26879da5 | 595 | ipc6.opt = opt; |
a32e0eec CE |
596 | |
597 | fl6.flowi6_proto = sk->sk_protocol; | |
598 | if (!ipv6_addr_any(daddr)) | |
599 | fl6.daddr = *daddr; | |
600 | else | |
601 | fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ | |
602 | if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) | |
603 | fl6.saddr = np->saddr; | |
604 | ||
605 | final_p = fl6_update_dst(&fl6, opt, &final); | |
606 | ||
607 | if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) | |
608 | fl6.flowi6_oif = np->mcast_oif; | |
609 | else if (!fl6.flowi6_oif) | |
610 | fl6.flowi6_oif = np->ucast_oif; | |
611 | ||
3df98d79 | 612 | security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); |
a32e0eec | 613 | |
38b7097b HFS |
614 | if (ipc6.tclass < 0) |
615 | ipc6.tclass = np->tclass; | |
616 | ||
617 | fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); | |
618 | ||
c4e85f73 | 619 | dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); |
a32e0eec CE |
620 | if (IS_ERR(dst)) { |
621 | err = PTR_ERR(dst); | |
622 | goto out; | |
623 | } | |
624 | ||
26879da5 WW |
625 | if (ipc6.hlimit < 0) |
626 | ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); | |
a32e0eec | 627 | |
26879da5 WW |
628 | if (ipc6.dontfrag < 0) |
629 | ipc6.dontfrag = np->dontfrag; | |
a32e0eec CE |
630 | |
631 | if (msg->msg_flags & MSG_CONFIRM) | |
632 | goto do_confirm; | |
633 | ||
634 | back_from_confirm: | |
635 | lock_sock(sk); | |
f69e6d13 | 636 | err = ip6_append_data(sk, ip_generic_getfrag, msg, |
26879da5 | 637 | ulen, transhdrlen, &ipc6, |
a32e0eec | 638 | &fl6, (struct rt6_info *)dst, |
5fdaa88d | 639 | msg->msg_flags); |
a32e0eec CE |
640 | if (err) |
641 | ip6_flush_pending_frames(sk); | |
642 | else if (!(msg->msg_flags & MSG_MORE)) | |
643 | err = l2tp_ip6_push_pending_frames(sk); | |
644 | release_sock(sk); | |
645 | done: | |
646 | dst_release(dst); | |
647 | out: | |
648 | fl6_sock_release(flowlabel); | |
45f6fad8 | 649 | txopt_put(opt_to_free); |
a32e0eec CE |
650 | |
651 | return err < 0 ? err : len; | |
652 | ||
653 | do_confirm: | |
0dec879f JA |
654 | if (msg->msg_flags & MSG_PROBE) |
655 | dst_confirm_neigh(dst, &fl6.daddr); | |
a32e0eec CE |
656 | if (!(msg->msg_flags & MSG_PROBE) || len) |
657 | goto back_from_confirm; | |
658 | err = 0; | |
659 | goto done; | |
660 | } | |
661 | ||
1b784140 | 662 | static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, |
ec095263 | 663 | int flags, int *addr_len) |
a32e0eec | 664 | { |
700163db | 665 | struct ipv6_pinfo *np = inet6_sk(sk); |
342dfc30 | 666 | DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name); |
a32e0eec CE |
667 | size_t copied = 0; |
668 | int err = -EOPNOTSUPP; | |
669 | struct sk_buff *skb; | |
670 | ||
671 | if (flags & MSG_OOB) | |
672 | goto out; | |
673 | ||
a32e0eec | 674 | if (flags & MSG_ERRQUEUE) |
85fbaa75 | 675 | return ipv6_recv_error(sk, msg, len, addr_len); |
a32e0eec | 676 | |
f4b41f06 | 677 | skb = skb_recv_datagram(sk, flags, &err); |
a32e0eec CE |
678 | if (!skb) |
679 | goto out; | |
680 | ||
681 | copied = skb->len; | |
682 | if (len < copied) { | |
683 | msg->msg_flags |= MSG_TRUNC; | |
684 | copied = len; | |
685 | } | |
686 | ||
51f3d02b | 687 | err = skb_copy_datagram_msg(skb, 0, msg, copied); |
a32e0eec CE |
688 | if (err) |
689 | goto done; | |
690 | ||
691 | sock_recv_timestamp(msg, sk, skb); | |
692 | ||
693 | /* Copy the address. */ | |
694 | if (lsa) { | |
695 | lsa->l2tp_family = AF_INET6; | |
696 | lsa->l2tp_unused = 0; | |
697 | lsa->l2tp_addr = ipv6_hdr(skb)->saddr; | |
698 | lsa->l2tp_flowinfo = 0; | |
699 | lsa->l2tp_scope_id = 0; | |
b860d3cc | 700 | lsa->l2tp_conn_id = 0; |
a32e0eec | 701 | if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) |
4330487a | 702 | lsa->l2tp_scope_id = inet6_iif(skb); |
163d1c3d | 703 | *addr_len = sizeof(*lsa); |
a32e0eec CE |
704 | } |
705 | ||
700163db TP |
706 | if (np->rxopt.all) |
707 | ip6_datagram_recv_ctl(sk, msg, skb); | |
a32e0eec CE |
708 | |
709 | if (flags & MSG_TRUNC) | |
710 | copied = skb->len; | |
711 | done: | |
712 | skb_free_datagram(sk, skb); | |
713 | out: | |
714 | return err ? err : copied; | |
715 | } | |
716 | ||
717 | static struct proto l2tp_ip6_prot = { | |
718 | .name = "L2TP/IPv6", | |
719 | .owner = THIS_MODULE, | |
720 | .init = l2tp_ip6_open, | |
721 | .close = l2tp_ip6_close, | |
722 | .bind = l2tp_ip6_bind, | |
723 | .connect = l2tp_ip6_connect, | |
c51ce497 | 724 | .disconnect = l2tp_ip6_disconnect, |
72fb96e7 | 725 | .ioctl = l2tp_ioctl, |
a32e0eec CE |
726 | .destroy = l2tp_ip6_destroy_sock, |
727 | .setsockopt = ipv6_setsockopt, | |
728 | .getsockopt = ipv6_getsockopt, | |
729 | .sendmsg = l2tp_ip6_sendmsg, | |
730 | .recvmsg = l2tp_ip6_recvmsg, | |
731 | .backlog_rcv = l2tp_ip6_backlog_recv, | |
02c71b14 ED |
732 | .hash = l2tp_ip6_hash, |
733 | .unhash = l2tp_ip6_unhash, | |
a32e0eec | 734 | .obj_size = sizeof(struct l2tp_ip6_sock), |
a32e0eec CE |
735 | }; |
736 | ||
737 | static const struct proto_ops l2tp_ip6_ops = { | |
738 | .family = PF_INET6, | |
739 | .owner = THIS_MODULE, | |
740 | .release = inet6_release, | |
741 | .bind = inet6_bind, | |
742 | .connect = inet_dgram_connect, | |
743 | .socketpair = sock_no_socketpair, | |
744 | .accept = sock_no_accept, | |
745 | .getname = l2tp_ip6_getname, | |
a11e1d43 | 746 | .poll = datagram_poll, |
a32e0eec | 747 | .ioctl = inet6_ioctl, |
c7cbdbf2 | 748 | .gettstamp = sock_gettstamp, |
a32e0eec CE |
749 | .listen = sock_no_listen, |
750 | .shutdown = inet_shutdown, | |
751 | .setsockopt = sock_common_setsockopt, | |
752 | .getsockopt = sock_common_getsockopt, | |
753 | .sendmsg = inet_sendmsg, | |
754 | .recvmsg = sock_common_recvmsg, | |
755 | .mmap = sock_no_mmap, | |
756 | .sendpage = sock_no_sendpage, | |
757 | #ifdef CONFIG_COMPAT | |
3986912f | 758 | .compat_ioctl = inet6_compat_ioctl, |
a32e0eec CE |
759 | #endif |
760 | }; | |
761 | ||
762 | static struct inet_protosw l2tp_ip6_protosw = { | |
763 | .type = SOCK_DGRAM, | |
764 | .protocol = IPPROTO_L2TP, | |
765 | .prot = &l2tp_ip6_prot, | |
766 | .ops = &l2tp_ip6_ops, | |
a32e0eec CE |
767 | }; |
768 | ||
769 | static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { | |
770 | .handler = l2tp_ip6_recv, | |
771 | }; | |
772 | ||
773 | static int __init l2tp_ip6_init(void) | |
774 | { | |
775 | int err; | |
776 | ||
a4ca44fa | 777 | pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); |
a32e0eec CE |
778 | |
779 | err = proto_register(&l2tp_ip6_prot, 1); | |
780 | if (err != 0) | |
781 | goto out; | |
782 | ||
783 | err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); | |
784 | if (err) | |
785 | goto out1; | |
786 | ||
787 | inet6_register_protosw(&l2tp_ip6_protosw); | |
788 | return 0; | |
789 | ||
790 | out1: | |
791 | proto_unregister(&l2tp_ip6_prot); | |
792 | out: | |
793 | return err; | |
794 | } | |
795 | ||
796 | static void __exit l2tp_ip6_exit(void) | |
797 | { | |
798 | inet6_unregister_protosw(&l2tp_ip6_protosw); | |
799 | inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); | |
800 | proto_unregister(&l2tp_ip6_prot); | |
801 | } | |
802 | ||
803 | module_init(l2tp_ip6_init); | |
804 | module_exit(l2tp_ip6_exit); | |
805 | ||
806 | MODULE_LICENSE("GPL"); | |
807 | MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); | |
808 | MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); | |
809 | MODULE_VERSION("1.0"); | |
810 | ||
811 | /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like | |
812 | * enums | |
813 | */ | |
814 | MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP); | |
163c2e25 | 815 | MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP); |