Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 1 | /* |
| 2 | * L2TPv3 IP encapsulation support for IPv6 |
| 3 | * |
| 4 | * Copyright (c) 2012 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 Perches | a4ca44f | 2012-05-16 09:55:56 +0000 | [diff] [blame] | 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 13 | |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 14 | #include <linux/icmp.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | #include <linux/random.h> |
| 18 | #include <linux/socket.h> |
| 19 | #include <linux/l2tp.h> |
| 20 | #include <linux/in.h> |
| 21 | #include <linux/in6.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> |
| 27 | #include <net/inet_hashtables.h> |
| 28 | #include <net/tcp_states.h> |
| 29 | #include <net/protocol.h> |
| 30 | #include <net/xfrm.h> |
| 31 | |
| 32 | #include <net/transp_v6.h> |
| 33 | #include <net/addrconf.h> |
| 34 | #include <net/ip6_route.h> |
| 35 | |
| 36 | #include "l2tp_core.h" |
| 37 | |
| 38 | struct l2tp_ip6_sock { |
| 39 | /* inet_sock has to be the first member of l2tp_ip6_sock */ |
| 40 | struct inet_sock inet; |
| 41 | |
| 42 | u32 conn_id; |
| 43 | u32 peer_conn_id; |
| 44 | |
| 45 | /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see |
| 46 | inet6_sk_generic */ |
| 47 | struct ipv6_pinfo inet6; |
| 48 | }; |
| 49 | |
| 50 | static DEFINE_RWLOCK(l2tp_ip6_lock); |
| 51 | static struct hlist_head l2tp_ip6_table; |
| 52 | static struct hlist_head l2tp_ip6_bind_table; |
| 53 | |
| 54 | static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk) |
| 55 | { |
| 56 | return (struct l2tp_ip6_sock *)sk; |
| 57 | } |
| 58 | |
| 59 | static struct sock *__l2tp_ip6_bind_lookup(struct net *net, |
| 60 | struct in6_addr *laddr, |
| 61 | int dif, u32 tunnel_id) |
| 62 | { |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 63 | struct sock *sk; |
| 64 | |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 65 | sk_for_each_bound(sk, &l2tp_ip6_bind_table) { |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 66 | const struct in6_addr *addr = inet6_rcv_saddr(sk); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 67 | struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk); |
| 68 | |
| 69 | if (l2tp == NULL) |
| 70 | continue; |
| 71 | |
| 72 | if ((l2tp->conn_id == tunnel_id) && |
| 73 | net_eq(sock_net(sk), net) && |
| 74 | !(addr && ipv6_addr_equal(addr, laddr)) && |
| 75 | !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)) |
| 76 | goto found; |
| 77 | } |
| 78 | |
| 79 | sk = NULL; |
| 80 | found: |
| 81 | return sk; |
| 82 | } |
| 83 | |
| 84 | static inline struct sock *l2tp_ip6_bind_lookup(struct net *net, |
| 85 | struct in6_addr *laddr, |
| 86 | int dif, u32 tunnel_id) |
| 87 | { |
| 88 | struct sock *sk = __l2tp_ip6_bind_lookup(net, laddr, dif, tunnel_id); |
| 89 | if (sk) |
| 90 | sock_hold(sk); |
| 91 | |
| 92 | return sk; |
| 93 | } |
| 94 | |
| 95 | /* When processing receive frames, there are two cases to |
| 96 | * consider. Data frames consist of a non-zero session-id and an |
| 97 | * optional cookie. Control frames consist of a regular L2TP header |
| 98 | * preceded by 32-bits of zeros. |
| 99 | * |
| 100 | * L2TPv3 Session Header Over IP |
| 101 | * |
| 102 | * 0 1 2 3 |
| 103 | * 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 |
| 104 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 105 | * | Session ID | |
| 106 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 107 | * | Cookie (optional, maximum 64 bits)... |
| 108 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 109 | * | |
| 110 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 111 | * |
| 112 | * L2TPv3 Control Message Header Over IP |
| 113 | * |
| 114 | * 0 1 2 3 |
| 115 | * 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 |
| 116 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 117 | * | (32 bits of zeros) | |
| 118 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 119 | * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length | |
| 120 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 121 | * | Control Connection ID | |
| 122 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 123 | * | Ns | Nr | |
| 124 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 125 | * |
| 126 | * All control frames are passed to userspace. |
| 127 | */ |
| 128 | static int l2tp_ip6_recv(struct sk_buff *skb) |
| 129 | { |
| 130 | struct sock *sk; |
| 131 | u32 session_id; |
| 132 | u32 tunnel_id; |
| 133 | unsigned char *ptr, *optr; |
| 134 | struct l2tp_session *session; |
| 135 | struct l2tp_tunnel *tunnel = NULL; |
| 136 | int length; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 137 | |
| 138 | /* Point to L2TP header */ |
| 139 | optr = ptr = skb->data; |
| 140 | |
| 141 | if (!pskb_may_pull(skb, 4)) |
| 142 | goto discard; |
| 143 | |
| 144 | session_id = ntohl(*((__be32 *) ptr)); |
| 145 | ptr += 4; |
| 146 | |
| 147 | /* RFC3931: L2TP/IP packets have the first 4 bytes containing |
| 148 | * the session_id. If it is 0, the packet is a L2TP control |
| 149 | * frame and the session_id value can be discarded. |
| 150 | */ |
| 151 | if (session_id == 0) { |
| 152 | __skb_pull(skb, 4); |
| 153 | goto pass_up; |
| 154 | } |
| 155 | |
| 156 | /* Ok, this is a data packet. Lookup the session. */ |
| 157 | session = l2tp_session_find(&init_net, NULL, session_id); |
| 158 | if (session == NULL) |
| 159 | goto discard; |
| 160 | |
| 161 | tunnel = session->tunnel; |
| 162 | if (tunnel == NULL) |
| 163 | goto discard; |
| 164 | |
| 165 | /* Trace packet contents, if enabled */ |
| 166 | if (tunnel->debug & L2TP_MSG_DATA) { |
| 167 | length = min(32u, skb->len); |
| 168 | if (!pskb_may_pull(skb, length)) |
| 169 | goto discard; |
| 170 | |
Joe Perches | a4ca44f | 2012-05-16 09:55:56 +0000 | [diff] [blame] | 171 | pr_debug("%s: ip recv\n", tunnel->name); |
| 172 | print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 173 | } |
| 174 | |
| 175 | l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, |
| 176 | tunnel->recv_payload_hook); |
| 177 | return 0; |
| 178 | |
| 179 | pass_up: |
| 180 | /* Get the tunnel_id from the L2TP header */ |
| 181 | if (!pskb_may_pull(skb, 12)) |
| 182 | goto discard; |
| 183 | |
| 184 | if ((skb->data[0] & 0xc0) != 0xc0) |
| 185 | goto discard; |
| 186 | |
| 187 | tunnel_id = ntohl(*(__be32 *) &skb->data[4]); |
| 188 | tunnel = l2tp_tunnel_find(&init_net, tunnel_id); |
| 189 | if (tunnel != NULL) |
| 190 | sk = tunnel->sock; |
| 191 | else { |
| 192 | struct ipv6hdr *iph = ipv6_hdr(skb); |
| 193 | |
| 194 | read_lock_bh(&l2tp_ip6_lock); |
| 195 | sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr, |
| 196 | 0, tunnel_id); |
| 197 | read_unlock_bh(&l2tp_ip6_lock); |
| 198 | } |
| 199 | |
| 200 | if (sk == NULL) |
| 201 | goto discard; |
| 202 | |
| 203 | sock_hold(sk); |
| 204 | |
| 205 | if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) |
| 206 | goto discard_put; |
| 207 | |
| 208 | nf_reset(skb); |
| 209 | |
| 210 | return sk_receive_skb(sk, skb, 1); |
| 211 | |
| 212 | discard_put: |
| 213 | sock_put(sk); |
| 214 | |
| 215 | discard: |
| 216 | kfree_skb(skb); |
| 217 | return 0; |
| 218 | } |
| 219 | |
| 220 | static int l2tp_ip6_open(struct sock *sk) |
| 221 | { |
| 222 | /* Prevent autobind. We don't have ports. */ |
| 223 | inet_sk(sk)->inet_num = IPPROTO_L2TP; |
| 224 | |
| 225 | write_lock_bh(&l2tp_ip6_lock); |
| 226 | sk_add_node(sk, &l2tp_ip6_table); |
| 227 | write_unlock_bh(&l2tp_ip6_lock); |
| 228 | |
| 229 | return 0; |
| 230 | } |
| 231 | |
| 232 | static void l2tp_ip6_close(struct sock *sk, long timeout) |
| 233 | { |
| 234 | write_lock_bh(&l2tp_ip6_lock); |
| 235 | hlist_del_init(&sk->sk_bind_node); |
| 236 | sk_del_node_init(sk); |
| 237 | write_unlock_bh(&l2tp_ip6_lock); |
| 238 | |
| 239 | sk_common_release(sk); |
| 240 | } |
| 241 | |
| 242 | static void l2tp_ip6_destroy_sock(struct sock *sk) |
| 243 | { |
Tom Parkin | 9360631 | 2013-03-19 06:11:15 +0000 | [diff] [blame] | 244 | struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk); |
| 245 | |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 246 | lock_sock(sk); |
| 247 | ip6_flush_pending_frames(sk); |
| 248 | release_sock(sk); |
| 249 | |
Tom Parkin | 9360631 | 2013-03-19 06:11:15 +0000 | [diff] [blame] | 250 | if (tunnel) { |
| 251 | l2tp_tunnel_closeall(tunnel); |
| 252 | sock_put(sk); |
| 253 | } |
| 254 | |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 255 | inet6_destroy_sock(sk); |
| 256 | } |
| 257 | |
| 258 | static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len) |
| 259 | { |
| 260 | struct inet_sock *inet = inet_sk(sk); |
| 261 | struct ipv6_pinfo *np = inet6_sk(sk); |
| 262 | struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr; |
| 263 | __be32 v4addr = 0; |
| 264 | int addr_type; |
| 265 | int err; |
| 266 | |
James Chapman | c51ce49 | 2012-05-29 03:30:42 +0000 | [diff] [blame] | 267 | if (!sock_flag(sk, SOCK_ZAPPED)) |
| 268 | return -EINVAL; |
| 269 | if (addr->l2tp_family != AF_INET6) |
| 270 | return -EINVAL; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 271 | if (addr_len < sizeof(*addr)) |
| 272 | return -EINVAL; |
| 273 | |
| 274 | addr_type = ipv6_addr_type(&addr->l2tp_addr); |
| 275 | |
| 276 | /* l2tp_ip6 sockets are IPv6 only */ |
| 277 | if (addr_type == IPV6_ADDR_MAPPED) |
| 278 | return -EADDRNOTAVAIL; |
| 279 | |
| 280 | /* L2TP is point-point, not multicast */ |
| 281 | if (addr_type & IPV6_ADDR_MULTICAST) |
| 282 | return -EADDRNOTAVAIL; |
| 283 | |
| 284 | err = -EADDRINUSE; |
| 285 | read_lock_bh(&l2tp_ip6_lock); |
| 286 | if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr, |
| 287 | sk->sk_bound_dev_if, addr->l2tp_conn_id)) |
| 288 | goto out_in_use; |
| 289 | read_unlock_bh(&l2tp_ip6_lock); |
| 290 | |
| 291 | lock_sock(sk); |
| 292 | |
| 293 | err = -EINVAL; |
| 294 | if (sk->sk_state != TCP_CLOSE) |
| 295 | goto out_unlock; |
| 296 | |
| 297 | /* Check if the address belongs to the host. */ |
| 298 | rcu_read_lock(); |
| 299 | if (addr_type != IPV6_ADDR_ANY) { |
| 300 | struct net_device *dev = NULL; |
| 301 | |
| 302 | if (addr_type & IPV6_ADDR_LINKLOCAL) { |
| 303 | if (addr_len >= sizeof(struct sockaddr_in6) && |
| 304 | addr->l2tp_scope_id) { |
| 305 | /* Override any existing binding, if another |
| 306 | * one is supplied by user. |
| 307 | */ |
| 308 | sk->sk_bound_dev_if = addr->l2tp_scope_id; |
| 309 | } |
| 310 | |
| 311 | /* Binding to link-local address requires an |
| 312 | interface */ |
| 313 | if (!sk->sk_bound_dev_if) |
| 314 | goto out_unlock_rcu; |
| 315 | |
| 316 | err = -ENODEV; |
| 317 | dev = dev_get_by_index_rcu(sock_net(sk), |
| 318 | sk->sk_bound_dev_if); |
| 319 | if (!dev) |
| 320 | goto out_unlock_rcu; |
| 321 | } |
| 322 | |
| 323 | /* ipv4 addr of the socket is invalid. Only the |
| 324 | * unspecified and mapped address have a v4 equivalent. |
| 325 | */ |
| 326 | v4addr = LOOPBACK4_IPV6; |
| 327 | err = -EADDRNOTAVAIL; |
| 328 | if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0)) |
| 329 | goto out_unlock_rcu; |
| 330 | } |
| 331 | rcu_read_unlock(); |
| 332 | |
| 333 | inet->inet_rcv_saddr = inet->inet_saddr = v4addr; |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 334 | sk->sk_v6_rcv_saddr = addr->l2tp_addr; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 335 | np->saddr = addr->l2tp_addr; |
| 336 | |
| 337 | l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id; |
| 338 | |
| 339 | write_lock_bh(&l2tp_ip6_lock); |
| 340 | sk_add_bind_node(sk, &l2tp_ip6_bind_table); |
| 341 | sk_del_node_init(sk); |
| 342 | write_unlock_bh(&l2tp_ip6_lock); |
| 343 | |
James Chapman | c51ce49 | 2012-05-29 03:30:42 +0000 | [diff] [blame] | 344 | sock_reset_flag(sk, SOCK_ZAPPED); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 345 | release_sock(sk); |
| 346 | return 0; |
| 347 | |
| 348 | out_unlock_rcu: |
| 349 | rcu_read_unlock(); |
| 350 | out_unlock: |
| 351 | release_sock(sk); |
| 352 | return err; |
| 353 | |
| 354 | out_in_use: |
| 355 | read_unlock_bh(&l2tp_ip6_lock); |
| 356 | return err; |
| 357 | } |
| 358 | |
| 359 | static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr, |
| 360 | int addr_len) |
| 361 | { |
| 362 | struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr; |
| 363 | struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr; |
| 364 | struct in6_addr *daddr; |
| 365 | int addr_type; |
| 366 | int rc; |
| 367 | |
James Chapman | c51ce49 | 2012-05-29 03:30:42 +0000 | [diff] [blame] | 368 | if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */ |
| 369 | return -EINVAL; |
| 370 | |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 371 | if (addr_len < sizeof(*lsa)) |
| 372 | return -EINVAL; |
| 373 | |
| 374 | addr_type = ipv6_addr_type(&usin->sin6_addr); |
| 375 | if (addr_type & IPV6_ADDR_MULTICAST) |
| 376 | return -EINVAL; |
| 377 | |
| 378 | if (addr_type & IPV6_ADDR_MAPPED) { |
| 379 | daddr = &usin->sin6_addr; |
| 380 | if (ipv4_is_multicast(daddr->s6_addr32[3])) |
| 381 | return -EINVAL; |
| 382 | } |
| 383 | |
| 384 | rc = ip6_datagram_connect(sk, uaddr, addr_len); |
| 385 | |
| 386 | lock_sock(sk); |
| 387 | |
| 388 | l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id; |
| 389 | |
| 390 | write_lock_bh(&l2tp_ip6_lock); |
| 391 | hlist_del_init(&sk->sk_bind_node); |
| 392 | sk_add_bind_node(sk, &l2tp_ip6_bind_table); |
| 393 | write_unlock_bh(&l2tp_ip6_lock); |
| 394 | |
| 395 | release_sock(sk); |
| 396 | |
| 397 | return rc; |
| 398 | } |
| 399 | |
James Chapman | c51ce49 | 2012-05-29 03:30:42 +0000 | [diff] [blame] | 400 | static int l2tp_ip6_disconnect(struct sock *sk, int flags) |
| 401 | { |
| 402 | if (sock_flag(sk, SOCK_ZAPPED)) |
| 403 | return 0; |
| 404 | |
| 405 | return udp_disconnect(sk, flags); |
| 406 | } |
| 407 | |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 408 | static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, |
| 409 | int *uaddr_len, int peer) |
| 410 | { |
| 411 | struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr; |
| 412 | struct sock *sk = sock->sk; |
| 413 | struct ipv6_pinfo *np = inet6_sk(sk); |
| 414 | struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk); |
| 415 | |
| 416 | lsa->l2tp_family = AF_INET6; |
| 417 | lsa->l2tp_flowinfo = 0; |
| 418 | lsa->l2tp_scope_id = 0; |
Mathias Krause | 04d4fbc | 2012-08-15 11:31:52 +0000 | [diff] [blame] | 419 | lsa->l2tp_unused = 0; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 420 | if (peer) { |
| 421 | if (!lsk->peer_conn_id) |
| 422 | return -ENOTCONN; |
| 423 | lsa->l2tp_conn_id = lsk->peer_conn_id; |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 424 | lsa->l2tp_addr = sk->sk_v6_daddr; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 425 | if (np->sndflow) |
| 426 | lsa->l2tp_flowinfo = np->flow_label; |
| 427 | } else { |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 428 | if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 429 | lsa->l2tp_addr = np->saddr; |
| 430 | else |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 431 | lsa->l2tp_addr = sk->sk_v6_rcv_saddr; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 432 | |
| 433 | lsa->l2tp_conn_id = lsk->conn_id; |
| 434 | } |
| 435 | if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) |
| 436 | lsa->l2tp_scope_id = sk->sk_bound_dev_if; |
| 437 | *uaddr_len = sizeof(*lsa); |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb) |
| 442 | { |
| 443 | int rc; |
| 444 | |
| 445 | /* Charge it to the socket, dropping if the queue is full. */ |
| 446 | rc = sock_queue_rcv_skb(sk, skb); |
| 447 | if (rc < 0) |
| 448 | goto drop; |
| 449 | |
| 450 | return 0; |
| 451 | |
| 452 | drop: |
| 453 | IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS); |
| 454 | kfree_skb(skb); |
| 455 | return -1; |
| 456 | } |
| 457 | |
| 458 | static int l2tp_ip6_push_pending_frames(struct sock *sk) |
| 459 | { |
| 460 | struct sk_buff *skb; |
| 461 | __be32 *transhdr = NULL; |
| 462 | int err = 0; |
| 463 | |
| 464 | skb = skb_peek(&sk->sk_write_queue); |
| 465 | if (skb == NULL) |
| 466 | goto out; |
| 467 | |
| 468 | transhdr = (__be32 *)skb_transport_header(skb); |
| 469 | *transhdr = 0; |
| 470 | |
| 471 | err = ip6_push_pending_frames(sk); |
| 472 | |
| 473 | out: |
| 474 | return err; |
| 475 | } |
| 476 | |
| 477 | /* Userspace will call sendmsg() on the tunnel socket to send L2TP |
| 478 | * control frames. |
| 479 | */ |
| 480 | static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk, |
| 481 | struct msghdr *msg, size_t len) |
| 482 | { |
| 483 | struct ipv6_txoptions opt_space; |
| 484 | struct sockaddr_l2tpip6 *lsa = |
| 485 | (struct sockaddr_l2tpip6 *) msg->msg_name; |
| 486 | struct in6_addr *daddr, *final_p, final; |
| 487 | struct ipv6_pinfo *np = inet6_sk(sk); |
| 488 | struct ipv6_txoptions *opt = NULL; |
| 489 | struct ip6_flowlabel *flowlabel = NULL; |
| 490 | struct dst_entry *dst = NULL; |
| 491 | struct flowi6 fl6; |
| 492 | int addr_len = msg->msg_namelen; |
| 493 | int hlimit = -1; |
| 494 | int tclass = -1; |
| 495 | int dontfrag = -1; |
| 496 | int transhdrlen = 4; /* zero session-id */ |
| 497 | int ulen = len + transhdrlen; |
| 498 | int err; |
| 499 | |
| 500 | /* Rough check on arithmetic overflow, |
| 501 | better check is made in ip6_append_data(). |
| 502 | */ |
| 503 | if (len > INT_MAX) |
| 504 | return -EMSGSIZE; |
| 505 | |
| 506 | /* Mirror BSD error message compatibility */ |
| 507 | if (msg->msg_flags & MSG_OOB) |
| 508 | return -EOPNOTSUPP; |
| 509 | |
| 510 | /* |
| 511 | * Get and verify the address. |
| 512 | */ |
| 513 | memset(&fl6, 0, sizeof(fl6)); |
| 514 | |
| 515 | fl6.flowi6_mark = sk->sk_mark; |
| 516 | |
| 517 | if (lsa) { |
| 518 | if (addr_len < SIN6_LEN_RFC2133) |
| 519 | return -EINVAL; |
| 520 | |
| 521 | if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6) |
| 522 | return -EAFNOSUPPORT; |
| 523 | |
| 524 | daddr = &lsa->l2tp_addr; |
| 525 | if (np->sndflow) { |
| 526 | fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK; |
| 527 | if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) { |
| 528 | flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); |
| 529 | if (flowlabel == NULL) |
| 530 | return -EINVAL; |
| 531 | daddr = &flowlabel->dst; |
| 532 | } |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * Otherwise it will be difficult to maintain |
| 537 | * sk->sk_dst_cache. |
| 538 | */ |
| 539 | if (sk->sk_state == TCP_ESTABLISHED && |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 540 | ipv6_addr_equal(daddr, &sk->sk_v6_daddr)) |
| 541 | daddr = &sk->sk_v6_daddr; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 542 | |
| 543 | if (addr_len >= sizeof(struct sockaddr_in6) && |
| 544 | lsa->l2tp_scope_id && |
| 545 | ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL) |
| 546 | fl6.flowi6_oif = lsa->l2tp_scope_id; |
| 547 | } else { |
| 548 | if (sk->sk_state != TCP_ESTABLISHED) |
| 549 | return -EDESTADDRREQ; |
| 550 | |
Eric Dumazet | efe4208 | 2013-10-03 15:42:29 -0700 | [diff] [blame] | 551 | daddr = &sk->sk_v6_daddr; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 552 | fl6.flowlabel = np->flow_label; |
| 553 | } |
| 554 | |
| 555 | if (fl6.flowi6_oif == 0) |
| 556 | fl6.flowi6_oif = sk->sk_bound_dev_if; |
| 557 | |
| 558 | if (msg->msg_controllen) { |
| 559 | opt = &opt_space; |
| 560 | memset(opt, 0, sizeof(struct ipv6_txoptions)); |
| 561 | opt->tot_len = sizeof(struct ipv6_txoptions); |
| 562 | |
Tom Parkin | 73df66f | 2013-01-31 01:02:24 +0000 | [diff] [blame] | 563 | err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt, |
| 564 | &hlimit, &tclass, &dontfrag); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 565 | if (err < 0) { |
| 566 | fl6_sock_release(flowlabel); |
| 567 | return err; |
| 568 | } |
| 569 | if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) { |
| 570 | flowlabel = fl6_sock_lookup(sk, fl6.flowlabel); |
| 571 | if (flowlabel == NULL) |
| 572 | return -EINVAL; |
| 573 | } |
| 574 | if (!(opt->opt_nflen|opt->opt_flen)) |
| 575 | opt = NULL; |
| 576 | } |
| 577 | |
| 578 | if (opt == NULL) |
| 579 | opt = np->opt; |
| 580 | if (flowlabel) |
| 581 | opt = fl6_merge_options(&opt_space, flowlabel, opt); |
| 582 | opt = ipv6_fixup_options(&opt_space, opt); |
| 583 | |
| 584 | fl6.flowi6_proto = sk->sk_protocol; |
| 585 | if (!ipv6_addr_any(daddr)) |
| 586 | fl6.daddr = *daddr; |
| 587 | else |
| 588 | fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ |
| 589 | if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) |
| 590 | fl6.saddr = np->saddr; |
| 591 | |
| 592 | final_p = fl6_update_dst(&fl6, opt, &final); |
| 593 | |
| 594 | if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) |
| 595 | fl6.flowi6_oif = np->mcast_oif; |
| 596 | else if (!fl6.flowi6_oif) |
| 597 | fl6.flowi6_oif = np->ucast_oif; |
| 598 | |
| 599 | security_sk_classify_flow(sk, flowi6_to_flowi(&fl6)); |
| 600 | |
| 601 | dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true); |
| 602 | if (IS_ERR(dst)) { |
| 603 | err = PTR_ERR(dst); |
| 604 | goto out; |
| 605 | } |
| 606 | |
| 607 | if (hlimit < 0) { |
| 608 | if (ipv6_addr_is_multicast(&fl6.daddr)) |
| 609 | hlimit = np->mcast_hops; |
| 610 | else |
| 611 | hlimit = np->hop_limit; |
| 612 | if (hlimit < 0) |
| 613 | hlimit = ip6_dst_hoplimit(dst); |
| 614 | } |
| 615 | |
| 616 | if (tclass < 0) |
| 617 | tclass = np->tclass; |
| 618 | |
| 619 | if (dontfrag < 0) |
| 620 | dontfrag = np->dontfrag; |
| 621 | |
| 622 | if (msg->msg_flags & MSG_CONFIRM) |
| 623 | goto do_confirm; |
| 624 | |
| 625 | back_from_confirm: |
| 626 | lock_sock(sk); |
| 627 | err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov, |
| 628 | ulen, transhdrlen, hlimit, tclass, opt, |
| 629 | &fl6, (struct rt6_info *)dst, |
| 630 | msg->msg_flags, dontfrag); |
| 631 | if (err) |
| 632 | ip6_flush_pending_frames(sk); |
| 633 | else if (!(msg->msg_flags & MSG_MORE)) |
| 634 | err = l2tp_ip6_push_pending_frames(sk); |
| 635 | release_sock(sk); |
| 636 | done: |
| 637 | dst_release(dst); |
| 638 | out: |
| 639 | fl6_sock_release(flowlabel); |
| 640 | |
| 641 | return err < 0 ? err : len; |
| 642 | |
| 643 | do_confirm: |
| 644 | dst_confirm(dst); |
| 645 | if (!(msg->msg_flags & MSG_PROBE) || len) |
| 646 | goto back_from_confirm; |
| 647 | err = 0; |
| 648 | goto done; |
| 649 | } |
| 650 | |
| 651 | static int l2tp_ip6_recvmsg(struct kiocb *iocb, struct sock *sk, |
| 652 | struct msghdr *msg, size_t len, int noblock, |
| 653 | int flags, int *addr_len) |
| 654 | { |
Tom Parkin | 700163d | 2013-01-31 01:02:26 +0000 | [diff] [blame] | 655 | struct ipv6_pinfo *np = inet6_sk(sk); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 656 | struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)msg->msg_name; |
| 657 | size_t copied = 0; |
| 658 | int err = -EOPNOTSUPP; |
| 659 | struct sk_buff *skb; |
| 660 | |
| 661 | if (flags & MSG_OOB) |
| 662 | goto out; |
| 663 | |
| 664 | if (addr_len) |
| 665 | *addr_len = sizeof(*lsa); |
| 666 | |
| 667 | if (flags & MSG_ERRQUEUE) |
Hannes Frederic Sowa | 85fbaa7 | 2013-11-23 00:46:12 +0100 | [diff] [blame] | 668 | return ipv6_recv_error(sk, msg, len, addr_len); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 669 | |
| 670 | skb = skb_recv_datagram(sk, flags, noblock, &err); |
| 671 | if (!skb) |
| 672 | goto out; |
| 673 | |
| 674 | copied = skb->len; |
| 675 | if (len < copied) { |
| 676 | msg->msg_flags |= MSG_TRUNC; |
| 677 | copied = len; |
| 678 | } |
| 679 | |
| 680 | err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); |
| 681 | if (err) |
| 682 | goto done; |
| 683 | |
| 684 | sock_recv_timestamp(msg, sk, skb); |
| 685 | |
| 686 | /* Copy the address. */ |
| 687 | if (lsa) { |
| 688 | lsa->l2tp_family = AF_INET6; |
| 689 | lsa->l2tp_unused = 0; |
| 690 | lsa->l2tp_addr = ipv6_hdr(skb)->saddr; |
| 691 | lsa->l2tp_flowinfo = 0; |
| 692 | lsa->l2tp_scope_id = 0; |
Mathias Krause | b860d3c | 2013-04-07 01:51:55 +0000 | [diff] [blame] | 693 | lsa->l2tp_conn_id = 0; |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 694 | if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL) |
| 695 | lsa->l2tp_scope_id = IP6CB(skb)->iif; |
| 696 | } |
| 697 | |
Tom Parkin | 700163d | 2013-01-31 01:02:26 +0000 | [diff] [blame] | 698 | if (np->rxopt.all) |
| 699 | ip6_datagram_recv_ctl(sk, msg, skb); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 700 | |
| 701 | if (flags & MSG_TRUNC) |
| 702 | copied = skb->len; |
| 703 | done: |
| 704 | skb_free_datagram(sk, skb); |
| 705 | out: |
| 706 | return err ? err : copied; |
| 707 | } |
| 708 | |
| 709 | static struct proto l2tp_ip6_prot = { |
| 710 | .name = "L2TP/IPv6", |
| 711 | .owner = THIS_MODULE, |
| 712 | .init = l2tp_ip6_open, |
| 713 | .close = l2tp_ip6_close, |
| 714 | .bind = l2tp_ip6_bind, |
| 715 | .connect = l2tp_ip6_connect, |
James Chapman | c51ce49 | 2012-05-29 03:30:42 +0000 | [diff] [blame] | 716 | .disconnect = l2tp_ip6_disconnect, |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 717 | .ioctl = udp_ioctl, |
| 718 | .destroy = l2tp_ip6_destroy_sock, |
| 719 | .setsockopt = ipv6_setsockopt, |
| 720 | .getsockopt = ipv6_getsockopt, |
| 721 | .sendmsg = l2tp_ip6_sendmsg, |
| 722 | .recvmsg = l2tp_ip6_recvmsg, |
| 723 | .backlog_rcv = l2tp_ip6_backlog_recv, |
| 724 | .hash = inet_hash, |
| 725 | .unhash = inet_unhash, |
| 726 | .obj_size = sizeof(struct l2tp_ip6_sock), |
| 727 | #ifdef CONFIG_COMPAT |
| 728 | .compat_setsockopt = compat_ipv6_setsockopt, |
| 729 | .compat_getsockopt = compat_ipv6_getsockopt, |
| 730 | #endif |
| 731 | }; |
| 732 | |
| 733 | static const struct proto_ops l2tp_ip6_ops = { |
| 734 | .family = PF_INET6, |
| 735 | .owner = THIS_MODULE, |
| 736 | .release = inet6_release, |
| 737 | .bind = inet6_bind, |
| 738 | .connect = inet_dgram_connect, |
| 739 | .socketpair = sock_no_socketpair, |
| 740 | .accept = sock_no_accept, |
| 741 | .getname = l2tp_ip6_getname, |
| 742 | .poll = datagram_poll, |
| 743 | .ioctl = inet6_ioctl, |
| 744 | .listen = sock_no_listen, |
| 745 | .shutdown = inet_shutdown, |
| 746 | .setsockopt = sock_common_setsockopt, |
| 747 | .getsockopt = sock_common_getsockopt, |
| 748 | .sendmsg = inet_sendmsg, |
| 749 | .recvmsg = sock_common_recvmsg, |
| 750 | .mmap = sock_no_mmap, |
| 751 | .sendpage = sock_no_sendpage, |
| 752 | #ifdef CONFIG_COMPAT |
| 753 | .compat_setsockopt = compat_sock_common_setsockopt, |
| 754 | .compat_getsockopt = compat_sock_common_getsockopt, |
| 755 | #endif |
| 756 | }; |
| 757 | |
| 758 | static struct inet_protosw l2tp_ip6_protosw = { |
| 759 | .type = SOCK_DGRAM, |
| 760 | .protocol = IPPROTO_L2TP, |
| 761 | .prot = &l2tp_ip6_prot, |
| 762 | .ops = &l2tp_ip6_ops, |
| 763 | .no_check = 0, |
| 764 | }; |
| 765 | |
| 766 | static struct inet6_protocol l2tp_ip6_protocol __read_mostly = { |
| 767 | .handler = l2tp_ip6_recv, |
| 768 | }; |
| 769 | |
| 770 | static int __init l2tp_ip6_init(void) |
| 771 | { |
| 772 | int err; |
| 773 | |
Joe Perches | a4ca44f | 2012-05-16 09:55:56 +0000 | [diff] [blame] | 774 | pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n"); |
Chris Elston | a32e0ee | 2012-04-29 21:48:54 +0000 | [diff] [blame] | 775 | |
| 776 | err = proto_register(&l2tp_ip6_prot, 1); |
| 777 | if (err != 0) |
| 778 | goto out; |
| 779 | |
| 780 | err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); |
| 781 | if (err) |
| 782 | goto out1; |
| 783 | |
| 784 | inet6_register_protosw(&l2tp_ip6_protosw); |
| 785 | return 0; |
| 786 | |
| 787 | out1: |
| 788 | proto_unregister(&l2tp_ip6_prot); |
| 789 | out: |
| 790 | return err; |
| 791 | } |
| 792 | |
| 793 | static void __exit l2tp_ip6_exit(void) |
| 794 | { |
| 795 | inet6_unregister_protosw(&l2tp_ip6_protosw); |
| 796 | inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP); |
| 797 | proto_unregister(&l2tp_ip6_prot); |
| 798 | } |
| 799 | |
| 800 | module_init(l2tp_ip6_init); |
| 801 | module_exit(l2tp_ip6_exit); |
| 802 | |
| 803 | MODULE_LICENSE("GPL"); |
| 804 | MODULE_AUTHOR("Chris Elston <celston@katalix.com>"); |
| 805 | MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6"); |
| 806 | MODULE_VERSION("1.0"); |
| 807 | |
| 808 | /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like |
| 809 | * enums |
| 810 | */ |
| 811 | MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP); |