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 return -EAFNOSUPPORT; 164 #endif 165 } 166 167 int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, u8 ds) 168 { 169 size_t skb_len = skb->len; 170 int ret = -EAFNOSUPPORT; 171 172 read_lock_bh(&peer->endpoint_lock); 173 if (peer->endpoint.addr.sa_family == AF_INET) 174 ret = send4(peer->device, skb, &peer->endpoint, ds, 175 &peer->endpoint_cache); 176 else if (peer->endpoint.addr.sa_family == AF_INET6) 177 ret = send6(peer->device, skb, &peer->endpoint, ds, 178 &peer->endpoint_cache); 179 else 180 dev_kfree_skb(skb); 181 if (likely(!ret)) 182 peer->tx_bytes += skb_len; 183 read_unlock_bh(&peer->endpoint_lock); 184 185 return ret; 186 } 187 188 int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *buffer, 189 size_t len, u8 ds) 190 { 191 struct sk_buff *skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); 192 193 if (unlikely(!skb)) 194 return -ENOMEM; 195 196 skb_reserve(skb, SKB_HEADER_LEN); 197 skb_set_inner_network_header(skb, 0); 198 skb_put_data(skb, buffer, len); 199 return wg_socket_send_skb_to_peer(peer, skb, ds); 200 } 201 202 int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg, 203 struct sk_buff *in_skb, void *buffer, 204 size_t len) 205 { 206 int ret = 0; 207 struct sk_buff *skb; 208 struct endpoint endpoint; 209 210 if (unlikely(!in_skb)) 211 return -EINVAL; 212 ret = wg_socket_endpoint_from_skb(&endpoint, in_skb); 213 if (unlikely(ret < 0)) 214 return ret; 215 216 skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); 217 if (unlikely(!skb)) 218 return -ENOMEM; 219 skb_reserve(skb, SKB_HEADER_LEN); 220 skb_set_inner_network_header(skb, 0); 221 skb_put_data(skb, buffer, len); 222 223 if (endpoint.addr.sa_family == AF_INET) 224 ret = send4(wg, skb, &endpoint, 0, NULL); 225 else if (endpoint.addr.sa_family == AF_INET6) 226 ret = send6(wg, skb, &endpoint, 0, NULL); 227 /* No other possibilities if the endpoint is valid, which it is, 228 * as we checked above. 229 */ 230 231 return ret; 232 } 233 234 int wg_socket_endpoint_from_skb(struct endpoint *endpoint, 235 const struct sk_buff *skb) 236 { 237 memset(endpoint, 0, sizeof(*endpoint)); 238 if (skb->protocol == htons(ETH_P_IP)) { 239 endpoint->addr4.sin_family = AF_INET; 240 endpoint->addr4.sin_port = udp_hdr(skb)->source; 241 endpoint->addr4.sin_addr.s_addr = ip_hdr(skb)->saddr; 242 endpoint->src4.s_addr = ip_hdr(skb)->daddr; 243 endpoint->src_if4 = skb->skb_iif; 244 } else if (skb->protocol == htons(ETH_P_IPV6)) { 245 endpoint->addr6.sin6_family = AF_INET6; 246 endpoint->addr6.sin6_port = udp_hdr(skb)->source; 247 endpoint->addr6.sin6_addr = ipv6_hdr(skb)->saddr; 248 endpoint->addr6.sin6_scope_id = ipv6_iface_scope_id( 249 &ipv6_hdr(skb)->saddr, skb->skb_iif); 250 endpoint->src6 = ipv6_hdr(skb)->daddr; 251 } else { 252 return -EINVAL; 253 } 254 return 0; 255 } 256 257 static bool endpoint_eq(const struct endpoint *a, const struct endpoint *b) 258 { 259 return (a->addr.sa_family == AF_INET && b->addr.sa_family == AF_INET && 260 a->addr4.sin_port == b->addr4.sin_port && 261 a->addr4.sin_addr.s_addr == b->addr4.sin_addr.s_addr && 262 a->src4.s_addr == b->src4.s_addr && a->src_if4 == b->src_if4) || 263 (a->addr.sa_family == AF_INET6 && 264 b->addr.sa_family == AF_INET6 && 265 a->addr6.sin6_port == b->addr6.sin6_port && 266 ipv6_addr_equal(&a->addr6.sin6_addr, &b->addr6.sin6_addr) && 267 a->addr6.sin6_scope_id == b->addr6.sin6_scope_id && 268 ipv6_addr_equal(&a->src6, &b->src6)) || 269 unlikely(!a->addr.sa_family && !b->addr.sa_family); 270 } 271 272 void wg_socket_set_peer_endpoint(struct wg_peer *peer, 273 const struct endpoint *endpoint) 274 { 275 /* First we check unlocked, in order to optimize, since it's pretty rare 276 * that an endpoint will change. If we happen to be mid-write, and two 277 * CPUs wind up writing the same thing or something slightly different, 278 * it doesn't really matter much either. 279 */ 280 if (endpoint_eq(endpoint, &peer->endpoint)) 281 return; 282 write_lock_bh(&peer->endpoint_lock); 283 if (endpoint->addr.sa_family == AF_INET) { 284 peer->endpoint.addr4 = endpoint->addr4; 285 peer->endpoint.src4 = endpoint->src4; 286 peer->endpoint.src_if4 = endpoint->src_if4; 287 } else if (endpoint->addr.sa_family == AF_INET6) { 288 peer->endpoint.addr6 = endpoint->addr6; 289 peer->endpoint.src6 = endpoint->src6; 290 } else { 291 goto out; 292 } 293 dst_cache_reset(&peer->endpoint_cache); 294 out: 295 write_unlock_bh(&peer->endpoint_lock); 296 } 297 298 void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer, 299 const struct sk_buff *skb) 300 { 301 struct endpoint endpoint; 302 303 if (!wg_socket_endpoint_from_skb(&endpoint, skb)) 304 wg_socket_set_peer_endpoint(peer, &endpoint); 305 } 306 307 void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer) 308 { 309 write_lock_bh(&peer->endpoint_lock); 310 memset(&peer->endpoint.src6, 0, sizeof(peer->endpoint.src6)); 311 dst_cache_reset(&peer->endpoint_cache); 312 write_unlock_bh(&peer->endpoint_lock); 313 } 314 315 static int wg_receive(struct sock *sk, struct sk_buff *skb) 316 { 317 struct wg_device *wg; 318 319 if (unlikely(!sk)) 320 goto err; 321 wg = sk->sk_user_data; 322 if (unlikely(!wg)) 323 goto err; 324 skb_mark_not_on_list(skb); 325 wg_packet_receive(wg, skb); 326 return 0; 327 328 err: 329 kfree_skb(skb); 330 return 0; 331 } 332 333 static void sock_free(struct sock *sock) 334 { 335 if (unlikely(!sock)) 336 return; 337 sk_clear_memalloc(sock); 338 udp_tunnel_sock_release(sock->sk_socket); 339 } 340 341 static void set_sock_opts(struct socket *sock) 342 { 343 sock->sk->sk_allocation = GFP_ATOMIC; 344 sock->sk->sk_sndbuf = INT_MAX; 345 sk_set_memalloc(sock->sk); 346 } 347 348 int wg_socket_init(struct wg_device *wg, u16 port) 349 { 350 struct net *net; 351 int ret; 352 struct udp_tunnel_sock_cfg cfg = { 353 .sk_user_data = wg, 354 .encap_type = 1, 355 .encap_rcv = wg_receive 356 }; 357 struct socket *new4 = NULL, *new6 = NULL; 358 struct udp_port_cfg port4 = { 359 .family = AF_INET, 360 .local_ip.s_addr = htonl(INADDR_ANY), 361 .local_udp_port = htons(port), 362 .use_udp_checksums = true 363 }; 364 #if IS_ENABLED(CONFIG_IPV6) 365 int retries = 0; 366 struct udp_port_cfg port6 = { 367 .family = AF_INET6, 368 .local_ip6 = IN6ADDR_ANY_INIT, 369 .use_udp6_tx_checksums = true, 370 .use_udp6_rx_checksums = true, 371 .ipv6_v6only = true 372 }; 373 #endif 374 375 rcu_read_lock(); 376 net = rcu_dereference(wg->creating_net); 377 net = net ? maybe_get_net(net) : NULL; 378 rcu_read_unlock(); 379 if (unlikely(!net)) 380 return -ENONET; 381 382 #if IS_ENABLED(CONFIG_IPV6) 383 retry: 384 #endif 385 386 ret = udp_sock_create(net, &port4, &new4); 387 if (ret < 0) { 388 pr_err("%s: Could not create IPv4 socket\n", wg->dev->name); 389 goto out; 390 } 391 set_sock_opts(new4); 392 setup_udp_tunnel_sock(net, new4, &cfg); 393 394 #if IS_ENABLED(CONFIG_IPV6) 395 if (ipv6_mod_enabled()) { 396 port6.local_udp_port = inet_sk(new4->sk)->inet_sport; 397 ret = udp_sock_create(net, &port6, &new6); 398 if (ret < 0) { 399 udp_tunnel_sock_release(new4); 400 if (ret == -EADDRINUSE && !port && retries++ < 100) 401 goto retry; 402 pr_err("%s: Could not create IPv6 socket\n", 403 wg->dev->name); 404 goto out; 405 } 406 set_sock_opts(new6); 407 setup_udp_tunnel_sock(net, new6, &cfg); 408 } 409 #endif 410 411 wg_socket_reinit(wg, new4->sk, new6 ? new6->sk : NULL); 412 ret = 0; 413 out: 414 put_net(net); 415 return ret; 416 } 417 418 void wg_socket_reinit(struct wg_device *wg, struct sock *new4, 419 struct sock *new6) 420 { 421 struct sock *old4, *old6; 422 423 mutex_lock(&wg->socket_update_lock); 424 old4 = rcu_dereference_protected(wg->sock4, 425 lockdep_is_held(&wg->socket_update_lock)); 426 old6 = rcu_dereference_protected(wg->sock6, 427 lockdep_is_held(&wg->socket_update_lock)); 428 rcu_assign_pointer(wg->sock4, new4); 429 rcu_assign_pointer(wg->sock6, new6); 430 if (new4) 431 wg->incoming_port = ntohs(inet_sk(new4)->inet_sport); 432 mutex_unlock(&wg->socket_update_lock); 433 synchronize_net(); 434 sock_free(old4); 435 sock_free(old6); 436 } 437