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1// SPDX-License-Identifier: GPL-2.02/*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 20static 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_UDP29 };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 90err:91 kfree_skb(skb);92out:93 rcu_read_unlock_bh();94 return ret;95}96 97static 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_UDP108 /* 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 157err:158 kfree_skb(skb);159out:160 rcu_read_unlock_bh();161 return ret;162#else163 kfree_skb(skb);164 return -EAFNOSUPPORT;165#endif166}167 168int 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 else181 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 189int 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 203int 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 235int 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 258static 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 273void 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 rare277 * that an endpoint will change. If we happen to be mid-write, and two278 * 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);295out:296 write_unlock_bh(&peer->endpoint_lock);297}298 299void 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 308void 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 316static 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 329err:330 kfree_skb(skb);331 return 0;332}333 334static 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 342static 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 349int 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_receive357 };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 = true364 };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 = true373 };374#endif375 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)384retry:385#endif386 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#endif411 412 wg_socket_reinit(wg, new4->sk, new6 ? new6->sk : NULL);413 ret = 0;414out:415 put_net(net);416 return ret;417}418 419void 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