1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 4 */ 5 6 #include "device.h" 7 #include "peer.h" 8 #include "socket.h" 9 #include "queueing.h" 10 #include "messages.h" 11 12 #include <linux/ctype.h> 13 #include <linux/net.h> 14 #include <linux/if_vlan.h> 15 #include <linux/if_ether.h> 16 #include <linux/inetdevice.h> 17 #include <net/udp_tunnel.h> 18 #include <net/ipv6.h> 19 20 static int send4(struct wg_device *wg, struct sk_buff *skb, 21 struct endpoint *endpoint, u8 ds, struct dst_cache *cache) 22 { 23 struct flowi4 fl = { 24 .saddr = endpoint->src4.s_addr, 25 .daddr = endpoint->addr4.sin_addr.s_addr, 26 .fl4_dport = endpoint->addr4.sin_port, 27 .flowi4_mark = wg->fwmark, 28 .flowi4_proto = IPPROTO_UDP 29 }; 30 struct rtable *rt = NULL; 31 struct sock *sock; 32 int ret = 0; 33 34 skb_mark_not_on_list(skb); 35 skb->dev = wg->dev; 36 skb->mark = wg->fwmark; 37 38 rcu_read_lock_bh(); 39 sock = rcu_dereference_bh(wg->sock4); 40 41 if (unlikely(!sock)) { 42 ret = -ENONET; 43 goto err; 44 } 45 46 fl.fl4_sport = inet_sk(sock)->inet_sport; 47 48 if (cache) 49 rt = dst_cache_get_ip4(cache, &fl.saddr); 50 51 if (!rt) { 52 security_sk_classify_flow(sock, flowi4_to_flowi_common(&fl)); 53 if (unlikely(!inet_confirm_addr(sock_net(sock), NULL, 0, 54 fl.saddr, RT_SCOPE_HOST))) { 55 endpoint->src4.s_addr = 0; 56 endpoint->src_if4 = 0; 57 fl.saddr = 0; 58 if (cache) 59 dst_cache_reset(cache); 60 } 61 rt = ip_route_output_flow(sock_net(sock), &fl, sock); 62 if (unlikely(endpoint->src_if4 && ((IS_ERR(rt) && 63 PTR_ERR(rt) == -EINVAL) || (!IS_ERR(rt) && 64 rt->dst.dev->ifindex != endpoint->src_if4)))) { 65 endpoint->src4.s_addr = 0; 66 endpoint->src_if4 = 0; 67 fl.saddr = 0; 68 if (cache) 69 dst_cache_reset(cache); 70 if (!IS_ERR(rt)) 71 ip_rt_put(rt); 72 rt = ip_route_output_flow(sock_net(sock), &fl, sock); 73 } 74 if (IS_ERR(rt)) { 75 ret = PTR_ERR(rt); 76 net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n", 77 wg->dev->name, &endpoint->addr, ret); 78 goto err; 79 } 80 if (cache) 81 dst_cache_set_ip4(cache, &rt->dst, fl.saddr); 82 } 83 84 skb->ignore_df = 1; 85 udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds, 86 ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport, 87 fl.fl4_dport, false, false); 88 goto out; 89 90 err: 91 kfree_skb(skb); 92 out: 93 rcu_read_unlock_bh(); 94 return ret; 95 } 96 97 static int send6(struct wg_device *wg, struct sk_buff *skb, 98 struct endpoint *endpoint, u8 ds, struct dst_cache *cache) 99 { 100 #if IS_ENABLED(CONFIG_IPV6) 101 struct flowi6 fl = { 102 .saddr = endpoint->src6, 103 .daddr = endpoint->addr6.sin6_addr, 104 .fl6_dport = endpoint->addr6.sin6_port, 105 .flowi6_mark = wg->fwmark, 106 .flowi6_oif = endpoint->addr6.sin6_scope_id, 107 .flowi6_proto = IPPROTO_UDP 108 /* TODO: addr->sin6_flowinfo */ 109 }; 110 struct dst_entry *dst = NULL; 111 struct sock *sock; 112 int ret = 0; 113 114 skb_mark_not_on_list(skb); 115 skb->dev = wg->dev; 116 skb->mark = wg->fwmark; 117 118 rcu_read_lock_bh(); 119 sock = rcu_dereference_bh(wg->sock6); 120 121 if (unlikely(!sock)) { 122 ret = -ENONET; 123 goto err; 124 } 125 126 fl.fl6_sport = inet_sk(sock)->inet_sport; 127 128 if (cache) 129 dst = dst_cache_get_ip6(cache, &fl.saddr); 130 131 if (!dst) { 132 security_sk_classify_flow(sock, flowi6_to_flowi_common(&fl)); 133 if (unlikely(!ipv6_addr_any(&fl.saddr) && 134 !ipv6_chk_addr(sock_net(sock), &fl.saddr, NULL, 0))) { 135 endpoint->src6 = fl.saddr = in6addr_any; 136 if (cache) 137 dst_cache_reset(cache); 138 } 139 dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sock), sock, &fl, 140 NULL); 141 if (IS_ERR(dst)) { 142 ret = PTR_ERR(dst); 143 net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n", 144 wg->dev->name, &endpoint->addr, ret); 145 goto err; 146 } 147 if (cache) 148 dst_cache_set_ip6(cache, dst, &fl.saddr); 149 } 150 151 skb->ignore_df = 1; 152 udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds, 153 ip6_dst_hoplimit(dst), 0, fl.fl6_sport, 154 fl.fl6_dport, false); 155 goto out; 156 157 err: 158 kfree_skb(skb); 159 out: 160 rcu_read_unlock_bh(); 161 return ret; 162 #else 163 kfree_skb(skb); 164 return -EAFNOSUPPORT; 165 #endif 166 } 167 168 int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, u8 ds) 169 { 170 size_t skb_len = skb->len; 171 int ret = -EAFNOSUPPORT; 172 173 read_lock_bh(&peer->endpoint_lock); 174 if (peer->endpoint.addr.sa_family == AF_INET) 175 ret = send4(peer->device, skb, &peer->endpoint, ds, 176 &peer->endpoint_cache); 177 else if (peer->endpoint.addr.sa_family == AF_INET6) 178 ret = send6(peer->device, skb, &peer->endpoint, ds, 179 &peer->endpoint_cache); 180 else 181 dev_kfree_skb(skb); 182 if (likely(!ret)) 183 peer->tx_bytes += skb_len; 184 read_unlock_bh(&peer->endpoint_lock); 185 186 return ret; 187 } 188 189 int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *buffer, 190 size_t len, u8 ds) 191 { 192 struct sk_buff *skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); 193 194 if (unlikely(!skb)) 195 return -ENOMEM; 196 197 skb_reserve(skb, SKB_HEADER_LEN); 198 skb_set_inner_network_header(skb, 0); 199 skb_put_data(skb, buffer, len); 200 return wg_socket_send_skb_to_peer(peer, skb, ds); 201 } 202 203 int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg, 204 struct sk_buff *in_skb, void *buffer, 205 size_t len) 206 { 207 int ret = 0; 208 struct sk_buff *skb; 209 struct endpoint endpoint; 210 211 if (unlikely(!in_skb)) 212 return -EINVAL; 213 ret = wg_socket_endpoint_from_skb(&endpoint, in_skb); 214 if (unlikely(ret < 0)) 215 return ret; 216 217 skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); 218 if (unlikely(!skb)) 219 return -ENOMEM; 220 skb_reserve(skb, SKB_HEADER_LEN); 221 skb_set_inner_network_header(skb, 0); 222 skb_put_data(skb, buffer, len); 223 224 if (endpoint.addr.sa_family == AF_INET) 225 ret = send4(wg, skb, &endpoint, 0, NULL); 226 else if (endpoint.addr.sa_family == AF_INET6) 227 ret = send6(wg, skb, &endpoint, 0, NULL); 228 /* No other possibilities if the endpoint is valid, which it is, 229 * as we checked above. 230 */ 231 232 return ret; 233 } 234 235 int wg_socket_endpoint_from_skb(struct endpoint *endpoint, 236 const struct sk_buff *skb) 237 { 238 memset(endpoint, 0, sizeof(*endpoint)); 239 if (skb->protocol == htons(ETH_P_IP)) { 240 endpoint->addr4.sin_family = AF_INET; 241 endpoint->addr4.sin_port = udp_hdr(skb)->source; 242 endpoint->addr4.sin_addr.s_addr = ip_hdr(skb)->saddr; 243 endpoint->src4.s_addr = ip_hdr(skb)->daddr; 244 endpoint->src_if4 = skb->skb_iif; 245 } else if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { 246 endpoint->addr6.sin6_family = AF_INET6; 247 endpoint->addr6.sin6_port = udp_hdr(skb)->source; 248 endpoint->addr6.sin6_addr = ipv6_hdr(skb)->saddr; 249 endpoint->addr6.sin6_scope_id = ipv6_iface_scope_id( 250 &ipv6_hdr(skb)->saddr, skb->skb_iif); 251 endpoint->src6 = ipv6_hdr(skb)->daddr; 252 } else { 253 return -EINVAL; 254 } 255 return 0; 256 } 257 258 static bool endpoint_eq(const struct endpoint *a, const struct endpoint *b) 259 { 260 return (a->addr.sa_family == AF_INET && b->addr.sa_family == AF_INET && 261 a->addr4.sin_port == b->addr4.sin_port && 262 a->addr4.sin_addr.s_addr == b->addr4.sin_addr.s_addr && 263 a->src4.s_addr == b->src4.s_addr && a->src_if4 == b->src_if4) || 264 (a->addr.sa_family == AF_INET6 && 265 b->addr.sa_family == AF_INET6 && 266 a->addr6.sin6_port == b->addr6.sin6_port && 267 ipv6_addr_equal(&a->addr6.sin6_addr, &b->addr6.sin6_addr) && 268 a->addr6.sin6_scope_id == b->addr6.sin6_scope_id && 269 ipv6_addr_equal(&a->src6, &b->src6)) || 270 unlikely(!a->addr.sa_family && !b->addr.sa_family); 271 } 272 273 void wg_socket_set_peer_endpoint(struct wg_peer *peer, 274 const struct endpoint *endpoint) 275 { 276 /* First we check unlocked, in order to optimize, since it's pretty rare 277 * that an endpoint will change. If we happen to be mid-write, and two 278 * CPUs wind up writing the same thing or something slightly different, 279 * it doesn't really matter much either. 280 */ 281 if (endpoint_eq(endpoint, &peer->endpoint)) 282 return; 283 write_lock_bh(&peer->endpoint_lock); 284 if (endpoint->addr.sa_family == AF_INET) { 285 peer->endpoint.addr4 = endpoint->addr4; 286 peer->endpoint.src4 = endpoint->src4; 287 peer->endpoint.src_if4 = endpoint->src_if4; 288 } else if (IS_ENABLED(CONFIG_IPV6) && endpoint->addr.sa_family == AF_INET6) { 289 peer->endpoint.addr6 = endpoint->addr6; 290 peer->endpoint.src6 = endpoint->src6; 291 } else { 292 goto out; 293 } 294 dst_cache_reset(&peer->endpoint_cache); 295 out: 296 write_unlock_bh(&peer->endpoint_lock); 297 } 298 299 void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer, 300 const struct sk_buff *skb) 301 { 302 struct endpoint endpoint; 303 304 if (!wg_socket_endpoint_from_skb(&endpoint, skb)) 305 wg_socket_set_peer_endpoint(peer, &endpoint); 306 } 307 308 void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer) 309 { 310 write_lock_bh(&peer->endpoint_lock); 311 memset(&peer->endpoint.src6, 0, sizeof(peer->endpoint.src6)); 312 dst_cache_reset_now(&peer->endpoint_cache); 313 write_unlock_bh(&peer->endpoint_lock); 314 } 315 316 static int wg_receive(struct sock *sk, struct sk_buff *skb) 317 { 318 struct wg_device *wg; 319 320 if (unlikely(!sk)) 321 goto err; 322 wg = sk->sk_user_data; 323 if (unlikely(!wg)) 324 goto err; 325 skb_mark_not_on_list(skb); 326 wg_packet_receive(wg, skb); 327 return 0; 328 329 err: 330 kfree_skb(skb); 331 return 0; 332 } 333 334 static void sock_free(struct sock *sock) 335 { 336 if (unlikely(!sock)) 337 return; 338 sk_clear_memalloc(sock); 339 udp_tunnel_sock_release(sock->sk_socket); 340 } 341 342 static void set_sock_opts(struct socket *sock) 343 { 344 sock->sk->sk_allocation = GFP_ATOMIC; 345 sock->sk->sk_sndbuf = INT_MAX; 346 sk_set_memalloc(sock->sk); 347 } 348 349 int wg_socket_init(struct wg_device *wg, u16 port) 350 { 351 struct net *net; 352 int ret; 353 struct udp_tunnel_sock_cfg cfg = { 354 .sk_user_data = wg, 355 .encap_type = 1, 356 .encap_rcv = wg_receive 357 }; 358 struct socket *new4 = NULL, *new6 = NULL; 359 struct udp_port_cfg port4 = { 360 .family = AF_INET, 361 .local_ip.s_addr = htonl(INADDR_ANY), 362 .local_udp_port = htons(port), 363 .use_udp_checksums = true 364 }; 365 #if IS_ENABLED(CONFIG_IPV6) 366 int retries = 0; 367 struct udp_port_cfg port6 = { 368 .family = AF_INET6, 369 .local_ip6 = IN6ADDR_ANY_INIT, 370 .use_udp6_tx_checksums = true, 371 .use_udp6_rx_checksums = true, 372 .ipv6_v6only = true 373 }; 374 #endif 375 376 rcu_read_lock(); 377 net = rcu_dereference(wg->creating_net); 378 net = net ? maybe_get_net(net) : NULL; 379 rcu_read_unlock(); 380 if (unlikely(!net)) 381 return -ENONET; 382 383 #if IS_ENABLED(CONFIG_IPV6) 384 retry: 385 #endif 386 387 ret = udp_sock_create(net, &port4, &new4); 388 if (ret < 0) { 389 pr_err("%s: Could not create IPv4 socket\n", wg->dev->name); 390 goto out; 391 } 392 set_sock_opts(new4); 393 setup_udp_tunnel_sock(net, new4, &cfg); 394 395 #if IS_ENABLED(CONFIG_IPV6) 396 if (ipv6_mod_enabled()) { 397 port6.local_udp_port = inet_sk(new4->sk)->inet_sport; 398 ret = udp_sock_create(net, &port6, &new6); 399 if (ret < 0) { 400 udp_tunnel_sock_release(new4); 401 if (ret == -EADDRINUSE && !port && retries++ < 100) 402 goto retry; 403 pr_err("%s: Could not create IPv6 socket\n", 404 wg->dev->name); 405 goto out; 406 } 407 set_sock_opts(new6); 408 setup_udp_tunnel_sock(net, new6, &cfg); 409 } 410 #endif 411 412 wg_socket_reinit(wg, new4->sk, new6 ? new6->sk : NULL); 413 ret = 0; 414 out: 415 put_net(net); 416 return ret; 417 } 418 419 void wg_socket_reinit(struct wg_device *wg, struct sock *new4, 420 struct sock *new6) 421 { 422 struct sock *old4, *old6; 423 424 mutex_lock(&wg->socket_update_lock); 425 old4 = rcu_dereference_protected(wg->sock4, 426 lockdep_is_held(&wg->socket_update_lock)); 427 old6 = rcu_dereference_protected(wg->sock6, 428 lockdep_is_held(&wg->socket_update_lock)); 429 rcu_assign_pointer(wg->sock4, new4); 430 rcu_assign_pointer(wg->sock6, new6); 431 if (new4) 432 wg->incoming_port = ntohs(inet_sk(new4)->inet_sport); 433 mutex_unlock(&wg->socket_update_lock); 434 synchronize_net(); 435 sock_free(old4); 436 sock_free(old6); 437 } 438