pex.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2022 Felix Fietkau <nbd@nbd.name>
   4  */
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <arpa/inet.h>
   8 #include <netinet/in.h>
   9 #include <netinet/ip.h>
  10 #include <netinet/ip6.h>
  11 #include <netinet/udp.h>
  12 #include <fcntl.h>
  13 #include <stdlib.h>
  14 #include <inttypes.h>
  15 #include "unetd.h"
  16 #include "pex-msg.h"
  17
  18 static const char *pex_peer_id_str(const uint8_t *key)
  19 {
  20         static char str[20];
  21         int i;
  22
  23         for (i = 0; i < 8; i++)
  24                 sprintf(str + i * 2, "%02x", key[i]);
  25
  26         return str;
  27 }
  28
  29 static struct pex_hdr *
  30 pex_msg_init(struct network *net, uint8_t opcode)
  31 {
  32         return __pex_msg_init(net->config.pubkey, opcode);
  33 }
  34
  35 static struct pex_hdr *
  36 pex_msg_init_ext(struct network *net, uint8_t opcode, bool ext)
  37 {
  38         return __pex_msg_init_ext(net->config.pubkey, net->config.auth_key, opcode, ext);
  39 }
  40
  41 static struct network_peer *
  42 pex_msg_peer(struct network *net, const uint8_t *id)
  43 {
  44         struct network_peer *peer;
  45         uint8_t key[WG_KEY_LEN] = {};
  46
  47         memcpy(key, id, PEX_ID_LEN);
  48         peer = avl_find_ge_element(&net->peers.avl, key, peer, node.avl);
  49         if (!peer || memcmp(peer->key, key, PEX_ID_LEN) != 0) {
  50                 D_NET(net, "can't find peer %s", pex_peer_id_str(id));
  51                 return NULL;
  52         }
  53
  54         return peer;
  55 }
  56
  57 static void
  58 pex_get_peer_addr(struct sockaddr_in6 *sin6, struct network *net,
  59                   struct network_peer *peer)
  60 {
  61         *sin6 = (struct sockaddr_in6){
  62                 .sin6_family = AF_INET6,
  63                 .sin6_addr = peer->local_addr.in6,
  64                 .sin6_port = htons(peer->pex_port),
  65         };
  66 }
  67
  68 static void pex_msg_send(struct network *net, struct network_peer *peer)
  69 {
  70         struct sockaddr_in6 sin6 = {};
  71
  72         if (!peer || peer == &net->net_config.local_host->peer ||
  73             !peer->pex_port)
  74                 return;
  75
  76         pex_get_peer_addr(&sin6, net, peer);
  77         if (__pex_msg_send(net->pex.fd.fd, &sin6, NULL, 0) < 0)
  78                 D_PEER(net, peer, "pex_msg_send failed: %s", strerror(errno));
  79 }
  80
  81 static void pex_msg_send_ext(struct network *net, struct network_peer *peer,
  82                              struct sockaddr_in6 *addr)
  83 {
  84         char addrbuf[INET6_ADDRSTRLEN];
  85
  86         if (!addr)
  87                 return pex_msg_send(net, peer);
  88
  89         if (__pex_msg_send(-1, addr, NULL, 0) < 0)
  90                 D_NET(net, "pex_msg_send_ext(%s) failed: %s",
  91                       inet_ntop(addr->sin6_family, (const void *)&addr->sin6_addr, addrbuf,
  92                                 sizeof(addrbuf)),
  93                       strerror(errno));
  94 }
  95
  96 static void
  97 pex_send_hello(struct network *net, struct network_peer *peer)
  98 {
  99         struct pex_hello *data;
 100
 101         pex_msg_init(net, PEX_MSG_HELLO);
 102         data = pex_msg_append(sizeof(*data));
 103         if (peer->state.endpoint.sa.sa_family == AF_INET6)
 104             data->flags |= htons(PEER_EP_F_IPV6);
 105         if (network_get_local_addr(&data->local_addr, &peer->state.endpoint))
 106                 return;
 107
 108         pex_msg_send(net, peer);
 109 }
 110
 111 static int
 112 pex_msg_add_peer_endpoint(struct network *net, struct network_peer *peer,
 113                           struct network_peer *receiver)
 114 {
 115         struct pex_peer_endpoint *data;
 116         uint16_t flags = 0;
 117         const void *addr;
 118         int port;
 119         int len;
 120
 121         addr = network_endpoint_addr(&peer->state.endpoint, &len);
 122         port = peer->state.endpoint.in.sin_port;
 123         if (len > 4)
 124                 flags |= PEER_EP_F_IPV6;
 125         if (network_endpoint_addr_equal(&peer->state.endpoint,
 126                                         &receiver->state.endpoint)) {
 127                 if (!peer->state.has_local_ep_addr) {
 128                         D_PEER(net, peer, "can't send peer to %s, missing local address",
 129                                network_peer_name(receiver));
 130                         return -1;
 131                 }
 132
 133                 addr = &peer->state.local_ep_addr;
 134                 port = htons(peer->port);
 135                 flags |= PEER_EP_F_LOCAL;
 136         }
 137
 138         data = pex_msg_append(sizeof(*data));
 139         if (!data)
 140                 return -1;
 141
 142         memcpy(data->peer_id, peer->key, sizeof(data->peer_id));
 143         memcpy(data->addr, addr, len);
 144         data->port = port;
 145         data->flags = htons(flags);
 146         D_PEER(net, peer, "send endpoint to %s", network_peer_name(receiver));
 147
 148         return 0;
 149 }
 150
 151 static void
 152 network_pex_handle_endpoint_change(struct network *net, struct network_peer *peer)
 153 {
 154         struct network_peer *cur;
 155
 156         vlist_for_each_element(&net->peers, cur, node) {
 157                 if (cur == peer || !cur->state.connected)
 158                         continue;
 159
 160                 pex_msg_init(net, PEX_MSG_NOTIFY_PEERS);
 161                 if (pex_msg_add_peer_endpoint(net, peer, cur))
 162                         continue;
 163
 164                 pex_msg_send(net, cur);
 165         }
 166 }
 167
 168 static void
 169 network_pex_host_send_endpoint_notify(struct network *net, struct network_pex_host *host)
 170 {
 171         union {
 172                 struct {
 173                         struct ip ip;
 174                         struct udphdr udp;
 175                 } ipv4;
 176                 struct {
 177                         struct ip6_hdr ip;
 178                         struct udphdr udp;
 179                 } ipv6;
 180         } packet = {};
 181         struct udphdr *udp;
 182         union network_endpoint dest_ep;
 183         union network_addr local_addr = {};
 184         int len;
 185
 186         pex_msg_init_ext(net, PEX_MSG_ENDPOINT_NOTIFY, true);
 187
 188         memcpy(&dest_ep, &host->endpoint, sizeof(dest_ep));
 189
 190         /* work around issue with local address lookup for local broadcast */
 191         if (host->endpoint.sa.sa_family == AF_INET) {
 192                 uint8_t *data = (uint8_t *)&dest_ep.in.sin_addr;
 193
 194                 if (data[3] == 0xff)
 195                         data[3] = 0xfe;
 196         }
 197         network_get_local_addr(&local_addr, &dest_ep);
 198
 199         memset(&dest_ep, 0, sizeof(dest_ep));
 200         dest_ep.sa.sa_family = host->endpoint.sa.sa_family;
 201         if (host->endpoint.sa.sa_family == AF_INET) {
 202                 packet.ipv4.ip = (struct ip){
 203                         .ip_hl = 5,
 204                         .ip_v = 4,
 205                         .ip_ttl = 64,
 206                         .ip_p = IPPROTO_UDP,
 207                         .ip_src = local_addr.in,
 208                         .ip_dst = host->endpoint.in.sin_addr,
 209                 };
 210                 dest_ep.in.sin_addr = host->endpoint.in.sin_addr;
 211                 udp = &packet.ipv4.udp;
 212                 len = sizeof(packet.ipv4);
 213         } else {
 214                 packet.ipv6.ip = (struct ip6_hdr){
 215                         .ip6_flow = htonl(6 << 28),
 216                         .ip6_hops = 128,
 217                         .ip6_nxt = IPPROTO_UDP,
 218                         .ip6_src = local_addr.in6,
 219                         .ip6_dst = host->endpoint.in6.sin6_addr,
 220                 };
 221                 dest_ep.in6.sin6_addr = host->endpoint.in6.sin6_addr;
 222                 udp = &packet.ipv6.udp;
 223                 len = sizeof(packet.ipv6);
 224         }
 225
 226         udp->uh_sport = htons(net->net_config.local_host->peer.port);
 227         udp->uh_dport = host->endpoint.in6.sin6_port;
 228
 229         if (__pex_msg_send(-1, &dest_ep, &packet, len) < 0)
 230                 D_NET(net, "pex_msg_send_raw failed: %s", strerror(errno));
 231 }
 232
 233
 234 static void
 235 network_pex_host_send_port_notify(struct network *net, struct network_pex_host *host)
 236 {
 237         struct pex_endpoint_port_notify *data;
 238
 239         if (!net->stun.port_ext)
 240                 return;
 241
 242         pex_msg_init_ext(net, PEX_MSG_ENDPOINT_PORT_NOTIFY, true);
 243
 244         data = pex_msg_append(sizeof(*data));
 245         data->port = htons(net->stun.port_ext);
 246
 247         __pex_msg_send(-1, &host->endpoint, NULL, 0);
 248 }
 249
 250 static void
 251 network_pex_host_request_update(struct network *net, struct network_pex_host *host)
 252 {
 253         char addrstr[INET6_ADDRSTRLEN];
 254         uint64_t version = 0;
 255
 256         if (net->net_data_len)
 257                 version = net->net_data_version;
 258
 259         D("request network data from host %s",
 260           inet_ntop(host->endpoint.sa.sa_family,
 261                     (host->endpoint.sa.sa_family == AF_INET6 ?
 262                      (const void *)&host->endpoint.in6.sin6_addr :
 263                      (const void *)&host->endpoint.in.sin_addr),
 264                     addrstr, sizeof(addrstr)));
 265
 266         if (!pex_msg_update_request_init(net->config.pubkey, net->config.key,
 267                                          net->config.auth_key, &host->endpoint,
 268                                          version, true))
 269                 return;
 270
 271         __pex_msg_send(-1, &host->endpoint, NULL, 0);
 272
 273         if (!net->net_config.local_host)
 274                 return;
 275
 276         network_pex_host_send_port_notify(net, host);
 277         network_pex_host_send_endpoint_notify(net, host);
 278 }
 279
 280 static void
 281 network_pex_request_update_cb(struct uloop_timeout *t)
 282 {
 283         struct network *net = container_of(t, struct network, pex.request_update_timer);
 284         struct network_pex *pex = &net->pex;
 285         struct network_pex_host *host;
 286
 287         uloop_timeout_set(t, 5000);
 288
 289 retry:
 290         if (list_empty(&pex->hosts))
 291                 return;
 292
 293         host = list_first_entry(&pex->hosts, struct network_pex_host, list);
 294         if (host->timeout && host->timeout < unet_gettime()) {
 295                 list_del(&host->list);
 296                 free(host);
 297                 goto retry;
 298         }
 299
 300         list_move_tail(&host->list, &pex->hosts);
 301         network_pex_host_request_update(net, host);
 302 }
 303
 304 void network_pex_init(struct network *net)
 305 {
 306         struct network_pex *pex = &net->pex;
 307
 308         memset(pex, 0, sizeof(*pex));
 309         pex->fd.fd = -1;
 310         INIT_LIST_HEAD(&pex->hosts);
 311         pex->request_update_timer.cb = network_pex_request_update_cb;
 312 }
 313
 314 static void
 315 network_pex_query_hosts(struct network *net)
 316 {
 317         struct network_host *host;
 318         int rv = rand();
 319         int hosts = 0;
 320         int i;
 321
 322         pex_msg_init(net, PEX_MSG_QUERY);
 323
 324         avl_for_each_element(&net->hosts, host, node) {
 325                 struct network_peer *peer = &host->peer;
 326                 void *id;
 327
 328                 if ((net->stun.port_ext && host == net->net_config.local_host) ||
 329                     peer->state.connected || peer->endpoint)
 330                         continue;
 331
 332                 id = pex_msg_append(PEX_ID_LEN);
 333                 if (!id)
 334                         break;
 335
 336                 memcpy(id, peer->key, PEX_ID_LEN);
 337                 hosts++;
 338         }
 339
 340         if (!hosts)
 341                 return;
 342
 343         rv %= net->hosts.count;
 344         for (i = 0; i < 2; i++) {
 345                 avl_for_each_element(&net->hosts, host, node) {
 346                         struct network_peer *peer = &host->peer;
 347
 348                         if (rv > 0) {
 349                                 rv--;
 350                                 continue;
 351                         }
 352
 353                         if (host == net->net_config.local_host)
 354                                 continue;
 355
 356                         if (!peer->state.connected)
 357                                 continue;
 358
 359                         D_PEER(net, peer, "send query for %d hosts", hosts);
 360                         pex_msg_send(net, peer);
 361                         return;
 362                 }
 363         }
 364
 365 }
 366
 367 static void
 368 network_pex_send_ping(struct network *net, struct network_peer *peer)
 369 {
 370         if (peer->state.pinged || !peer->state.endpoint.sa.sa_family)
 371                 return;
 372
 373         pex_msg_init(net, PEX_MSG_PING);
 374         pex_msg_send(net, peer);
 375         peer->state.pinged = true;
 376 }
 377
 378 static void
 379 network_pex_send_update_request(struct network *net, struct network_peer *peer,
 380                                 struct sockaddr_in6 *addr)
 381 {
 382         union network_endpoint ep = {};
 383         uint64_t version = 0;
 384
 385         if (addr)
 386                 memcpy(&ep.in6, addr, sizeof(ep.in6));
 387         else
 388                 pex_get_peer_addr(&ep.in6, net, peer);
 389
 390         if (net->net_data_len)
 391                 version = net->net_data_version;
 392
 393         if (!pex_msg_update_request_init(net->config.pubkey, net->config.key,
 394                                          net->config.auth_key, &ep,
 395                                          version, !!addr))
 396                 return;
 397
 398         pex_msg_send_ext(net, peer, addr);
 399 }
 400
 401 void network_pex_event(struct network *net, struct network_peer *peer,
 402                        enum pex_event ev)
 403 {
 404         if (!network_pex_active(&net->pex))
 405                 return;
 406
 407         switch (ev) {
 408         case PEX_EV_HANDSHAKE:
 409                 pex_send_hello(net, peer);
 410                 if (net->config.type == NETWORK_TYPE_DYNAMIC)
 411                         network_pex_send_update_request(net, peer, NULL);
 412                 break;
 413         case PEX_EV_ENDPOINT_CHANGE:
 414                 network_pex_handle_endpoint_change(net, peer);
 415                 break;
 416         case PEX_EV_QUERY:
 417                 network_pex_query_hosts(net);
 418                 break;
 419         case PEX_EV_PING:
 420                 network_pex_send_ping(net, peer);
 421                 break;
 422         }
 423 }
 424
 425 static void
 426 network_pex_recv_hello(struct network *net, struct network_peer *peer,
 427                        const struct pex_hello *data, size_t len)
 428 {
 429         char addrstr[INET6_ADDRSTRLEN];
 430         uint16_t flags;
 431         int af;
 432
 433         if (len < sizeof(*data))
 434                 return;
 435
 436         if (peer->state.has_local_ep_addr &&
 437             !memcmp(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr)))
 438                 return;
 439
 440         flags = ntohs(data->flags);
 441         af = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 442         D_PEER(net, peer, "set local endpoint address to %s",
 443                inet_ntop(af, data->local_addr, addrstr, sizeof(addrstr)));
 444         peer->state.has_local_ep_addr = true;
 445         memcpy(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr));
 446 }
 447
 448 static void
 449 network_pex_recv_peers(struct network *net, struct network_peer *peer,
 450                        const struct pex_peer_endpoint *data, size_t len)
 451 {
 452         struct network_peer *local = &net->net_config.local_host->peer;
 453         struct network_peer *cur;
 454
 455         for (; len >= sizeof(*data); len -= sizeof(*data), data++) {
 456                 union network_endpoint *ep;
 457                 uint16_t flags;
 458                 void *addr;
 459                 int len;
 460
 461                 if (!memcmp(data->peer_id, &local->key, PEX_ID_LEN)) {
 462                         network_stun_update_port(net, false, ntohs(data->port));
 463                         continue;
 464                 }
 465
 466                 cur = pex_msg_peer(net, data->peer_id);
 467                 if (!cur || cur == peer)
 468                         continue;
 469
 470                 D_PEER(net, peer, "received peer address for %s",
 471                        network_peer_name(cur));
 472                 flags = ntohs(data->flags);
 473                 ep = &cur->state.next_endpoint;
 474                 ep->sa.sa_family = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 475                 addr = network_endpoint_addr(ep, &len);
 476                 memcpy(addr, data->addr, len);
 477                 ep->in.sin_port = data->port;
 478         }
 479 }
 480
 481 static void
 482 network_pex_recv_query(struct network *net, struct network_peer *peer,
 483                        const uint8_t *data, size_t len)
 484 {
 485         struct network_peer *cur;
 486         int resp = 0;
 487
 488         pex_msg_init(net, PEX_MSG_NOTIFY_PEERS);
 489         for (; len >= 8; data += 8, len -= 8) {
 490                 cur = pex_msg_peer(net, data);
 491                 if (!cur || !cur->state.connected)
 492                         continue;
 493
 494                 if (!pex_msg_add_peer_endpoint(net, cur, peer))
 495                         resp++;
 496         }
 497
 498         if (!resp)
 499                 return;
 500
 501         D_PEER(net, peer, "send query response with %d hosts", resp);
 502         pex_msg_send(net, peer);
 503 }
 504
 505 static void
 506 network_pex_recv_ping(struct network *net, struct network_peer *peer)
 507 {
 508         time_t now = time(NULL);
 509
 510         if (peer->state.last_request == now)
 511                 return;
 512
 513         peer->state.last_request = now;
 514         pex_msg_init(net, PEX_MSG_PONG);
 515         pex_msg_send(net, peer);
 516 }
 517
 518 static void
 519 network_pex_recv_update_request(struct network *net, struct network_peer *peer,
 520                                 const uint8_t *data, size_t len,
 521                                 struct sockaddr_in6 *addr)
 522 {
 523         struct pex_update_request *req = (struct pex_update_request *)data;
 524         struct pex_msg_update_send_ctx ctx = {};
 525         uint64_t req_version = be64_to_cpu(req->cur_version);
 526         int *query_count;
 527         bool done = false;
 528
 529         if (len < sizeof(struct pex_update_request))
 530                 return;
 531
 532         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 533                 return;
 534
 535         if (peer)
 536                 query_count = &peer->state.num_net_queries;
 537         else
 538                 query_count = &net->num_net_queries;
 539
 540         if (++*query_count > 10)
 541                 return;
 542
 543         D("receive update request, local version=%"PRIu64", remote version=%"PRIu64, net->net_data_version, req_version);
 544
 545         if (req_version >= net->net_data_version) {
 546                 struct pex_update_response_no_data *res;
 547
 548                 pex_msg_init_ext(net, PEX_MSG_UPDATE_RESPONSE_NO_DATA, !!addr);
 549                 res = pex_msg_append(sizeof(*res));
 550                 res->req_id = req->req_id;
 551                 res->cur_version = cpu_to_be64(net->net_data_version);
 552                 pex_msg_send_ext(net, peer, addr);
 553         }
 554
 555         if (req_version > net->net_data_version)
 556                 network_pex_send_update_request(net, peer, addr);
 557
 558         if (!peer || !net->net_data_len)
 559                 return;
 560
 561         if (req_version >= net->net_data_version)
 562                 return;
 563
 564         pex_msg_update_response_init(&ctx, net->config.pubkey, net->config.auth_key,
 565                                      peer->key, !!addr, (void *)data,
 566                                      net->net_data, net->net_data_len);
 567         while (!done) {
 568                 pex_msg_send_ext(net, peer, addr);
 569                 done = !pex_msg_update_response_continue(&ctx);
 570         }
 571 }
 572
 573 static void
 574 network_pex_recv_update_response(struct network *net, const uint8_t *data, size_t len,
 575                               struct sockaddr_in6 *addr, enum pex_opcode op)
 576 {
 577         struct network_peer *peer;
 578         void *net_data;
 579         int net_data_len = 0;
 580         uint64_t version = 0;
 581         bool no_prev_data = !net->net_data_len;
 582
 583         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 584                 return;
 585
 586         net_data = pex_msg_update_response_recv(data, len, op, &net_data_len, &version);
 587         if (!net_data)
 588                 return;
 589
 590         if (version <= net->net_data_version) {
 591                 free(net_data);
 592                 return;
 593         }
 594
 595         D_NET(net, "received updated network data, len=%d", net_data_len);
 596         free(net->net_data);
 597
 598         net->net_data = net_data;
 599         net->net_data_len = net_data_len;
 600         net->net_data_version = version;
 601         if (network_save_dynamic(net) < 0)
 602                 return;
 603
 604         uloop_timeout_set(&net->reload_timer, no_prev_data ? 1 : UNETD_DATA_UPDATE_DELAY);
 605         vlist_for_each_element(&net->peers, peer, node) {
 606                 if (!peer->state.connected || !peer->pex_port)
 607                         continue;
 608                 network_pex_send_update_request(net, peer, NULL);
 609         }
 610 }
 611
 612 static void
 613 network_pex_recv(struct network *net, struct network_peer *peer, struct pex_hdr *hdr)
 614 {
 615         const void *data = hdr + 1;
 616
 617         if (hdr->version != 0)
 618                 return;
 619
 620         D_PEER(net, peer, "PEX rx op=%d", hdr->opcode);
 621         switch (hdr->opcode) {
 622         case PEX_MSG_HELLO:
 623                 network_pex_recv_hello(net, peer, data, hdr->len);
 624                 break;
 625         case PEX_MSG_NOTIFY_PEERS:
 626                 network_pex_recv_peers(net, peer, data, hdr->len);
 627                 break;
 628         case PEX_MSG_QUERY:
 629                 network_pex_recv_query(net, peer, data, hdr->len);
 630                 break;
 631         case PEX_MSG_PING:
 632                 network_pex_recv_ping(net, peer);
 633                 break;
 634         case PEX_MSG_PONG:
 635                 break;
 636         case PEX_MSG_UPDATE_REQUEST:
 637                 network_pex_recv_update_request(net, peer, data, hdr->len,
 638                                                 NULL);
 639                 break;
 640         case PEX_MSG_UPDATE_RESPONSE:
 641         case PEX_MSG_UPDATE_RESPONSE_DATA:
 642         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 643                 network_pex_recv_update_response(net, data, hdr->len,
 644                                               NULL, hdr->opcode);
 645                 break;
 646         case PEX_MSG_ENDPOINT_NOTIFY:
 647                 break;
 648         }
 649 }
 650
 651 static void
 652 network_pex_fd_cb(struct uloop_fd *fd, unsigned int events)
 653 {
 654         struct network *net = container_of(fd, struct network, pex.fd);
 655         struct network_peer *local = &net->net_config.local_host->peer;
 656         struct network_peer *peer;
 657         struct sockaddr_in6 sin6;
 658         static char buf[PEX_BUF_SIZE];
 659         struct pex_hdr *hdr = (struct pex_hdr *)buf;
 660         ssize_t len;
 661
 662         while (1) {
 663                 socklen_t slen = sizeof(sin6);
 664
 665                 len = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&sin6, &slen);
 666                 if (len < 0) {
 667                         if (errno == EINTR)
 668                                 continue;
 669
 670                         if (errno == EAGAIN)
 671                                 break;
 672
 673                         D_NET(net, "recvfrom failed: %s", strerror(errno));
 674                         network_pex_close(net);
 675                         return;
 676                 }
 677
 678                 if (!len)
 679                         continue;
 680
 681                 hdr = pex_rx_accept(buf, len, false);
 682                 if (!hdr)
 683                         continue;
 684
 685                 peer = pex_msg_peer(net, hdr->id);
 686                 if (!peer)
 687                         continue;
 688
 689                 if (memcmp(&sin6.sin6_addr, &peer->local_addr.in6, sizeof(sin6.sin6_addr)) != 0)
 690                         continue;
 691
 692                 if (peer == local)
 693                         continue;
 694
 695                 network_pex_recv(net, peer, hdr);
 696         }
 697 }
 698
 699 void network_pex_create_host(struct network *net, union network_endpoint *ep,
 700                              unsigned int timeout)
 701 {
 702         struct network_pex *pex = &net->pex;
 703         struct network_pex_host *host;
 704         bool new_host = false;
 705
 706         list_for_each_entry(host, &pex->hosts, list) {
 707                 if (memcmp(&host->endpoint, ep, sizeof(host->endpoint)) != 0)
 708                         continue;
 709
 710                 list_move_tail(&host->list, &pex->hosts);
 711                 goto out;
 712         }
 713
 714         host = calloc(1, sizeof(*host));
 715         new_host = true;
 716         memcpy(&host->endpoint, ep, sizeof(host->endpoint));
 717         list_add_tail(&host->list, &pex->hosts);
 718
 719 out:
 720         if (timeout && (new_host || host->timeout))
 721                 host->timeout = timeout + unet_gettime();
 722         network_pex_host_request_update(net, host);
 723 }
 724
 725 static void
 726 network_pex_open_auth_connect(struct network *net)
 727 {
 728         struct network_pex *pex = &net->pex;
 729         struct network_peer *peer;
 730         struct blob_attr *cur;
 731         int rem;
 732
 733         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 734                 return;
 735
 736         uloop_timeout_set(&pex->request_update_timer, 5000);
 737
 738         vlist_for_each_element(&net->peers, peer, node) {
 739                 union network_endpoint ep = {};
 740
 741                 if (!peer->endpoint || peer->dynamic)
 742                         continue;
 743
 744                 if (network_get_endpoint(&ep, AF_UNSPEC, peer->endpoint,
 745                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 746                         continue;
 747
 748                 ep.in.sin_port = htons(UNETD_GLOBAL_PEX_PORT);
 749                 network_pex_create_host(net, &ep, 0);
 750         }
 751
 752         if (!net->config.auth_connect)
 753                 return;
 754
 755         blobmsg_for_each_attr(cur, net->config.auth_connect, rem) {
 756                 union network_endpoint ep = {};
 757
 758                 if (network_get_endpoint(&ep, AF_UNSPEC, blobmsg_get_string(cur),
 759                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 760                         continue;
 761
 762                 network_pex_create_host(net, &ep, 0);
 763         }
 764 }
 765
 766
 767 int network_pex_open(struct network *net)
 768 {
 769         struct network_host *local_host = net->net_config.local_host;
 770         struct network_peer *local;
 771         struct network_pex *pex = &net->pex;
 772         struct sockaddr_in6 sin6 = {};
 773         int yes = 1;
 774         int fd;
 775
 776         network_pex_open_auth_connect(net);
 777
 778         if (!local_host || !local_host->peer.pex_port)
 779                 return 0;
 780
 781         local = &local_host->peer;
 782         fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 783         if (fd < 0)
 784                 return -1;
 785
 786         fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
 787         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
 788
 789         sin6.sin6_family = AF_INET6;
 790         memcpy(&sin6.sin6_addr, &local->local_addr.in6,
 791                sizeof(local->local_addr.in6));
 792         sin6.sin6_port = htons(local_host->peer.pex_port);
 793
 794         if (bind(fd, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
 795                 perror("bind");
 796                 goto close;
 797         }
 798
 799         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
 800         setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes));
 801 #ifdef linux
 802         setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
 803                    network_name(net), strlen(network_name(net)));
 804 #endif
 805
 806         pex->fd.fd = fd;
 807         pex->fd.cb = network_pex_fd_cb;
 808         uloop_fd_add(&pex->fd, ULOOP_READ);
 809
 810         return 0;
 811
 812 close:
 813         close(fd);
 814         return -1;
 815 }
 816
 817 void network_pex_close(struct network *net)
 818 {
 819         struct network_pex *pex = &net->pex;
 820         struct network_pex_host *host, *tmp;
 821         uint64_t now = unet_gettime();
 822
 823         uloop_timeout_cancel(&pex->request_update_timer);
 824         list_for_each_entry_safe(host, tmp, &pex->hosts, list) {
 825                 if (host->timeout)
 826                         continue;
 827
 828                 if (host->last_active + UNETD_PEX_HOST_ACITVE_TIMEOUT >= now)
 829                         continue;
 830
 831                 list_del(&host->list);
 832                 free(host);
 833         }
 834
 835         if (pex->fd.fd < 0)
 836                 return;
 837
 838         uloop_fd_delete(&pex->fd);
 839         close(pex->fd.fd);
 840         network_pex_init(net);
 841 }
 842
 843 void network_pex_free(struct network *net)
 844 {
 845         struct network_pex *pex = &net->pex;
 846         struct network_pex_host *host, *tmp;
 847
 848         list_for_each_entry_safe(host, tmp, &pex->hosts, list) {
 849                 list_del(&host->list);
 850                 free(host);
 851         }
 852 }
 853
 854 static struct network *
 855 global_pex_find_network(const uint8_t *id)
 856 {
 857         struct network *net;
 858
 859         avl_for_each_element(&networks, net, node) {
 860                 if (!memcmp(id, net->config.auth_key, PEX_ID_LEN))
 861                         return net;
 862         }
 863
 864         return NULL;
 865 }
 866
 867 static void
 868 global_pex_set_active(struct network *net, struct sockaddr_in6 *addr)
 869 {
 870         struct network_pex *pex = &net->pex;
 871         struct network_pex_host *host;
 872
 873         list_for_each_entry(host, &pex->hosts, list) {
 874                 if (memcmp(&host->endpoint.in6, addr, sizeof(*addr)) != 0)
 875                         continue;
 876
 877                 host->last_active = unet_gettime();
 878         }
 879 }
 880
 881 static void
 882 global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 883 {
 884         struct pex_hdr *hdr;
 885         struct pex_ext_hdr *ehdr;
 886         struct network_peer *peer;
 887         struct network *net;
 888         char buf[INET6_ADDRSTRLEN];
 889         void *data;
 890         int addr_len;
 891
 892         if (stun_msg_is_valid(msg, msg_len)) {
 893                 avl_for_each_element(&networks, net, node)
 894                         network_stun_rx_packet(net, msg, msg_len);
 895         }
 896
 897         hdr = pex_rx_accept(msg, msg_len, true);
 898         if (!hdr)
 899                 return;
 900
 901         ehdr = (void *)(hdr + 1);
 902         data = (void *)(ehdr + 1);
 903
 904         if (hdr->version != 0)
 905                 return;
 906
 907         net = global_pex_find_network(ehdr->auth_id);
 908         if (!net || net->config.type != NETWORK_TYPE_DYNAMIC)
 909                 return;
 910
 911         *(uint64_t *)hdr->id ^= pex_network_hash(net->config.auth_key, ehdr->nonce);
 912
 913         global_pex_set_active(net, addr);
 914
 915         D("PEX global rx op=%d", hdr->opcode);
 916         switch (hdr->opcode) {
 917         case PEX_MSG_HELLO:
 918         case PEX_MSG_NOTIFY_PEERS:
 919         case PEX_MSG_QUERY:
 920         case PEX_MSG_PING:
 921         case PEX_MSG_PONG:
 922                 break;
 923         case PEX_MSG_UPDATE_REQUEST:
 924                 peer = pex_msg_peer(net, hdr->id);
 925                 network_pex_recv_update_request(net, peer, data, hdr->len,
 926                                                 addr);
 927                 break;
 928         case PEX_MSG_UPDATE_RESPONSE:
 929         case PEX_MSG_UPDATE_RESPONSE_DATA:
 930         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 931                 network_pex_recv_update_response(net, data, hdr->len, addr, hdr->opcode);
 932                 break;
 933         case PEX_MSG_ENDPOINT_PORT_NOTIFY:
 934                 if (hdr->len < sizeof(struct pex_endpoint_port_notify))
 935                         break;
 936         case PEX_MSG_ENDPOINT_NOTIFY:
 937                 peer = pex_msg_peer(net, hdr->id);
 938                 if (!peer)
 939                         break;
 940
 941                 D_PEER(net, peer, "receive endpoint notification from %s",
 942                   inet_ntop(addr->sin6_family, network_endpoint_addr((void *)addr, &addr_len),
 943                             buf, sizeof(buf)));
 944
 945                 memcpy(&peer->state.next_endpoint, addr, sizeof(*addr));
 946                 if (hdr->opcode == PEX_MSG_ENDPOINT_PORT_NOTIFY) {
 947                         struct pex_endpoint_port_notify *port = data;
 948
 949                         peer->state.next_endpoint.in.sin_port = port->port;
 950                 }
 951                 break;
 952         }
 953 }
 954
 955 static void
 956 pex_recv_control(struct pex_msg_local_control *msg, int len)
 957 {
 958         struct network *net;
 959
 960         if (msg->msg_type != 0)
 961                 return;
 962
 963         net = global_pex_find_network(msg->auth_id);
 964         if (!net)
 965                 return;
 966
 967         if (!msg->timeout)
 968                 msg->timeout = 60;
 969         network_pex_create_host(net, &msg->ep, msg->timeout);
 970 }
 971
 972 int global_pex_open(const char *unix_path)
 973 {
 974         struct sockaddr_in6 sin6 = {};
 975         int ret;
 976
 977         sin6.sin6_family = AF_INET6;
 978         sin6.sin6_port = htons(global_pex_port);
 979
 980         ret = pex_open(&sin6, sizeof(sin6), global_pex_recv, true);
 981
 982         if (unix_path)
 983                 pex_unix_open(unix_path, pex_recv_control);
 984
 985         return ret;
 986 }