summaryrefslogtreecommitdiffstats
path: root/src/plugins/wireguard/wireguard_send.c
blob: adfa5cac3de2675e4bd77798e437507e1bdaae5a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
/*
 * Copyright (c) 2020 Doc.ai and/or its affiliates.
 * Copyright (c) 2020 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vnet/vnet.h>
#include <vnet/ip/ip6_link.h>
#include <vppinfra/error.h>
#include <vlibmemory/api.h>
#include <wireguard/wireguard.h>
#include <wireguard/wireguard_send.h>

static int
ip46_enqueue_packet (vlib_main_t *vm, u32 bi0, int is_ip4)
{
  vlib_frame_t *f = 0;
  u32 lookup_node_index =
    is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index;

  f = vlib_get_frame_to_node (vm, lookup_node_index);
  /* f can not be NULL here - frame allocation failure causes panic */

  u32 *to_next = vlib_frame_vector_args (f);
  f->n_vectors = 1;
  to_next[0] = bi0;

  vlib_put_frame_to_node (vm, lookup_node_index, f);

  return f->n_vectors;
}

static void
wg_buffer_prepend_rewrite (vlib_buffer_t *b0, const u8 *rewrite, u8 is_ip4)
{
  if (is_ip4)
    {
      ip4_udp_header_t *hdr4;

      vlib_buffer_advance (b0, -sizeof (*hdr4));

      hdr4 = vlib_buffer_get_current (b0);

      /* copy only ip4 and udp header; wireguard header not needed */
      clib_memcpy (hdr4, rewrite, sizeof (ip4_udp_header_t));

      hdr4->udp.length =
	clib_host_to_net_u16 (b0->current_length - sizeof (ip4_header_t));
      ip4_header_set_len_w_chksum (&hdr4->ip4,
				   clib_host_to_net_u16 (b0->current_length));
    }
  else
    {
      ip6_udp_header_t *hdr6;

      vlib_buffer_advance (b0, -sizeof (*hdr6));

      hdr6 = vlib_buffer_get_current (b0);

      /* copy only ip6 and udp header; wireguard header not needed */
      clib_memcpy (hdr6, rewrite, sizeof (ip6_udp_header_t));

      hdr6->ip6.payload_length = hdr6->udp.length =
	clib_host_to_net_u16 (b0->current_length - sizeof (ip6_header_t));
    }
}

static bool
wg_create_buffer (vlib_main_t *vm, const u8 *rewrite, const u8 *packet,
		  u32 packet_len, u32 *bi, u8 is_ip4)
{
  u32 n_buf0 = 0;
  vlib_buffer_t *b0;

  n_buf0 = vlib_buffer_alloc (vm, bi, 1);
  if (!n_buf0)
    return false;

  b0 = vlib_get_buffer (vm, *bi);

  u8 *payload = vlib_buffer_get_current (b0);
  clib_memcpy (payload, packet, packet_len);

  b0->current_length = packet_len;

  wg_buffer_prepend_rewrite (b0, rewrite, is_ip4);

  return true;
}

u8 *
wg_build_rewrite (ip46_address_t *src_addr, u16 src_port,
		  ip46_address_t *dst_addr, u16 dst_port, u8 is_ip4)
{
  if (ip46_address_is_zero (dst_addr) || 0 == dst_port)
    return NULL;

  u8 *rewrite = NULL;
  if (is_ip4)
    {
      ip4_udp_header_t *hdr;

      /* reserve space for ip4, udp and wireguard headers */
      vec_validate (rewrite, sizeof (ip4_udp_wg_header_t) - 1);
      hdr = (ip4_udp_header_t *) rewrite;

      hdr->ip4.ip_version_and_header_length = 0x45;
      hdr->ip4.ttl = 64;
      hdr->ip4.src_address = src_addr->ip4;
      hdr->ip4.dst_address = dst_addr->ip4;
      hdr->ip4.protocol = IP_PROTOCOL_UDP;
      hdr->ip4.checksum = ip4_header_checksum (&hdr->ip4);

      hdr->udp.src_port = clib_host_to_net_u16 (src_port);
      hdr->udp.dst_port = clib_host_to_net_u16 (dst_port);
      hdr->udp.checksum = 0;
    }
  else
    {
      ip6_udp_header_t *hdr;

      /* reserve space for ip6, udp and wireguard headers */
      vec_validate (rewrite, sizeof (ip6_udp_wg_header_t) - 1);
      hdr = (ip6_udp_header_t *) rewrite;

      hdr->ip6.ip_version_traffic_class_and_flow_label = 0x60;
      ip6_address_copy (&hdr->ip6.src_address, &src_addr->ip6);
      ip6_address_copy (&hdr->ip6.dst_address, &dst_addr->ip6);
      hdr->ip6.protocol = IP_PROTOCOL_UDP;
      hdr->ip6.hop_limit = 64;

      hdr->udp.src_port = clib_host_to_net_u16 (src_port);
      hdr->udp.dst_port = clib_host_to_net_u16 (dst_port);
      hdr->udp.checksum = 0;
    }

  return (rewrite);
}

bool
wg_send_handshake (vlib_main_t * vm, wg_peer_t * peer, bool is_retry)
{
  ASSERT (vm->thread_index == 0);

  if (!wg_peer_can_send (peer))
    return false;

  message_handshake_initiation_t packet;

  if (!is_retry)
    peer->timer_handshake_attempts = 0;

  if (!wg_birthdate_has_expired (peer->last_sent_handshake, REKEY_TIMEOUT) ||
      wg_peer_is_dead (peer))
    return true;

  if (noise_create_initiation (vm,
			       &peer->remote,
			       &packet.sender_index,
			       packet.unencrypted_ephemeral,
			       packet.encrypted_static,
			       packet.encrypted_timestamp))
    {
      packet.header.type = MESSAGE_HANDSHAKE_INITIATION;
      cookie_maker_mac (&peer->cookie_maker, &packet.macs, &packet,
			sizeof (packet));
      wg_timers_any_authenticated_packet_sent (peer);
      wg_timers_handshake_initiated (peer);
      wg_timers_any_authenticated_packet_traversal (peer);

      peer->last_sent_handshake = vlib_time_now (vm);
    }
  else
    return false;

  u8 is_ip4 = ip46_address_is_ip4 (&peer->dst.addr);
  u32 bi0 = 0;
  if (!wg_create_buffer (vm, peer->rewrite, (u8 *) &packet, sizeof (packet),
			 &bi0, is_ip4))
    return false;

  ip46_enqueue_packet (vm, bi0, is_ip4);
  return true;
}

typedef struct
{
  u32 peer_idx;
  bool is_retry;
} wg_send_args_t;

static void *
wg_send_handshake_thread_fn (void *arg)
{
  wg_send_args_t *a = arg;

  wg_main_t *wmp = &wg_main;
  wg_peer_t *peer = wg_peer_get (a->peer_idx);

  wg_send_handshake (wmp->vlib_main, peer, a->is_retry);
  return 0;
}

void
wg_send_handshake_from_mt (u32 peer_idx, bool is_retry)
{
  wg_send_args_t a = {
    .peer_idx = peer_idx,
    .is_retry = is_retry,
  };

  vl_api_rpc_call_main_thread (wg_send_handshake_thread_fn,
			       (u8 *) & a, sizeof (a));
}

bool
wg_send_keepalive (vlib_main_t * vm, wg_peer_t * peer)
{
  ASSERT (vm->thread_index == 0);

  if (!wg_peer_can_send (peer))
    return false;

  u32 size_of_packet = message_data_len (0);
  message_data_t *packet =
    (message_data_t *) wg_main.per_thread_data[vm->thread_index].data;
  u32 bi0 = 0;
  bool ret = true;
  enum noise_state_crypt state;

  if (!peer->remote.r_current)
    {
      wg_send_handshake (vm, peer, false);
      goto out;
    }

  state =
    noise_remote_encrypt (vm,
			  &peer->remote,
			  &packet->receiver_index,
			  &packet->counter, NULL, 0, packet->encrypted_data);

  if (PREDICT_FALSE (state == SC_KEEP_KEY_FRESH))
    {
      wg_send_handshake (vm, peer, false);
    }
  else if (PREDICT_FALSE (state == SC_FAILED))
    {
      wg_peer_update_flags (peer - wg_peer_pool, WG_PEER_ESTABLISHED, false);
      ret = false;
      goto out;
    }

  u8 is_ip4 = ip46_address_is_ip4 (&peer->dst.addr);
  packet->header.type = MESSAGE_DATA;

  if (!wg_create_buffer (vm, peer->rewrite, (u8 *) packet, size_of_packet,
			 &bi0, is_ip4))
    {
      ret = false;
      goto out;
    }

  ip46_enqueue_packet (vm, bi0, is_ip4);

  wg_timers_any_authenticated_packet_sent (peer);
  wg_timers_any_authenticated_packet_traversal (peer);

out:
  return ret;
}

bool
wg_send_handshake_response (vlib_main_t * vm, wg_peer_t * peer)
{
  message_handshake_response_t packet;

  if (!wg_peer_can_send (peer))
    return false;

  if (noise_create_response (vm,
			     &peer->remote,
			     &packet.sender_index,
			     &packet.receiver_index,
			     packet.unencrypted_ephemeral,
			     packet.encrypted_nothing))
    {
      packet.header.type = MESSAGE_HANDSHAKE_RESPONSE;
      cookie_maker_mac (&peer->cookie_maker, &packet.macs, &packet,
			sizeof (packet));

      if (noise_remote_begin_session (vm, &peer->remote))
	{
	  wg_timers_session_derived (peer);
	  wg_timers_any_authenticated_packet_sent (peer);
	  wg_timers_any_authenticated_packet_traversal (peer);

	  u32 bi0 = 0;
	  u8 is_ip4 = ip46_address_is_ip4 (&peer->dst.addr);
	  if (!wg_create_buffer (vm, peer->rewrite, (u8 *) &packet,
				 sizeof (packet), &bi0, is_ip4))
	    return false;

	  ip46_enqueue_packet (vm, bi0, is_ip4);
	  return true;
	}
      return false;
    }
  return false;
}

bool
wg_send_handshake_cookie (vlib_main_t *vm, u32 sender_index,
			  cookie_checker_t *cookie_checker,
			  message_macs_t *macs, ip46_address_t *wg_if_addr,
			  u16 wg_if_port, ip46_address_t *remote_addr,
			  u16 remote_port)
{
  message_handshake_cookie_t packet;
  u8 *rewrite;

  packet.header.type = MESSAGE_HANDSHAKE_COOKIE;
  packet.receiver_index = sender_index;

  cookie_checker_create_payload (vm, cookie_checker, macs, packet.nonce,
				 packet.encrypted_cookie, remote_addr,
				 remote_port);

  u32 bi0 = 0;
  u8 is_ip4 = ip46_address_is_ip4 (remote_addr);
  bool ret;
  rewrite = wg_build_rewrite (wg_if_addr, wg_if_port, remote_addr, remote_port,
			      is_ip4);

  ret = wg_create_buffer (vm, rewrite, (u8 *) &packet, sizeof (packet), &bi0,
			  is_ip4);
  vec_free (rewrite);
  if (!ret)
    return false;

  ip46_enqueue_packet (vm, bi0, is_ip4);

  return true;
}

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */