Loading...
Note: File does not exist in v3.15.
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
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_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
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_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
157err:
158 kfree_skb(skb);
159out:
160 rcu_read_unlock_bh();
161 return ret;
162#else
163 return -EAFNOSUPPORT;
164#endif
165}
166
167int 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
188int 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
202int 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
234int 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
257static 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
272void 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);
294out:
295 write_unlock_bh(&peer->endpoint_lock);
296}
297
298void 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
307void 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
315static 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
328err:
329 kfree_skb(skb);
330 return 0;
331}
332
333static 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
341static 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
348int 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)
383retry:
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;
413out:
414 put_net(net);
415 return ret;
416}
417
418void 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}