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         host->last_ping = unet_gettime();
 257
 258         if (net->net_data_len)
 259                 version = net->net_data_version;
 260
 261         D("request network data from host %s",
 262           inet_ntop(host->endpoint.sa.sa_family,
 263                     (host->endpoint.sa.sa_family == AF_INET6 ?
 264                      (const void *)&host->endpoint.in6.sin6_addr :
 265                      (const void *)&host->endpoint.in.sin_addr),
 266                     addrstr, sizeof(addrstr)));
 267
 268         if (!pex_msg_update_request_init(net->config.pubkey, net->config.key,
 269                                          net->config.auth_key, &host->endpoint,
 270                                          version, true))
 271                 return;
 272
 273         __pex_msg_send(-1, &host->endpoint, NULL, 0);
 274
 275         if (!net->net_config.local_host)
 276                 return;
 277
 278         network_pex_host_send_port_notify(net, host);
 279         network_pex_host_send_endpoint_notify(net, host);
 280 }
 281
 282 static void
 283 network_pex_free_host(struct network *net, struct network_pex_host *host)
 284 {
 285         struct network_pex *pex = &net->pex;
 286
 287         pex->num_hosts--;
 288         list_del(&host->list);
 289         free(host);
 290 }
 291
 292 static void
 293 network_pex_request_update_cb(struct uloop_timeout *t)
 294 {
 295         struct network *net = container_of(t, struct network, pex.request_update_timer);
 296         struct network_pex *pex = &net->pex;
 297         struct network_pex_host *host, *tmp;
 298         uint64_t now = unet_gettime();
 299
 300         uloop_timeout_set(t, 500);
 301
 302         if (list_empty(&pex->hosts))
 303                 return;
 304
 305         list_for_each_entry_safe(host, tmp, &pex->hosts, list) {
 306                 if (host->timeout && host->timeout < now) {
 307                         network_pex_free_host(net, host);
 308                         continue;
 309                 }
 310
 311                 if (host->last_ping + 10 >= now)
 312                         continue;
 313
 314                 list_move_tail(&host->list, &pex->hosts);
 315                 network_pex_host_request_update(net, host);
 316         }
 317 }
 318
 319 void network_pex_init(struct network *net)
 320 {
 321         struct network_pex *pex = &net->pex;
 322
 323         memset(pex, 0, sizeof(*pex));
 324         pex->fd.fd = -1;
 325         INIT_LIST_HEAD(&pex->hosts);
 326         pex->request_update_timer.cb = network_pex_request_update_cb;
 327 }
 328
 329 static void
 330 network_pex_query_hosts(struct network *net)
 331 {
 332         struct network_host *host;
 333         uint64_t now;
 334         int rv = rand();
 335         int hosts = 0;
 336         int i;
 337
 338         pex_msg_init(net, PEX_MSG_QUERY);
 339
 340         avl_for_each_element(&net->hosts, host, node) {
 341                 struct network_peer *peer = &host->peer;
 342                 void *id;
 343
 344                 if ((net->stun.port_ext && host == net->net_config.local_host) ||
 345                     peer->state.connected || peer->endpoint)
 346                         continue;
 347
 348                 id = pex_msg_append(PEX_ID_LEN);
 349                 if (!id)
 350                         break;
 351
 352                 memcpy(id, peer->key, PEX_ID_LEN);
 353                 hosts++;
 354         }
 355
 356         if (!hosts)
 357                 return;
 358
 359         now = unet_gettime();
 360         rv %= net->hosts.count;
 361         for (i = 0; i < 2; i++) {
 362                 avl_for_each_element(&net->hosts, host, node) {
 363                         struct network_peer *peer = &host->peer;
 364
 365                         if (rv > 0) {
 366                                 rv--;
 367                                 continue;
 368                         }
 369
 370                         if (host == net->net_config.local_host)
 371                                 continue;
 372
 373                         if (!peer->state.connected ||
 374                             peer->state.last_query_sent + 15 >= now)
 375                                 continue;
 376
 377                         D_PEER(net, peer, "send query for %d hosts", hosts);
 378                         pex_msg_send(net, peer);
 379                         return;
 380                 }
 381         }
 382
 383 }
 384
 385 static void
 386 network_pex_send_ping(struct network *net, struct network_peer *peer)
 387 {
 388         if (peer->state.pinged || !peer->state.endpoint.sa.sa_family)
 389                 return;
 390
 391         pex_msg_init(net, PEX_MSG_PING);
 392         pex_msg_send(net, peer);
 393         peer->state.pinged = true;
 394 }
 395
 396 static void
 397 network_pex_send_update_request(struct network *net, struct network_peer *peer,
 398                                 struct sockaddr_in6 *addr)
 399 {
 400         union network_endpoint ep = {};
 401         uint64_t version = 0;
 402
 403         if (addr)
 404                 memcpy(&ep.in6, addr, sizeof(ep.in6));
 405         else
 406                 pex_get_peer_addr(&ep.in6, net, peer);
 407
 408         if (net->net_data_len)
 409                 version = net->net_data_version;
 410
 411         if (!pex_msg_update_request_init(net->config.pubkey, net->config.key,
 412                                          net->config.auth_key, &ep,
 413                                          version, !!addr))
 414                 return;
 415
 416         pex_msg_send_ext(net, peer, addr);
 417 }
 418
 419 void network_pex_event(struct network *net, struct network_peer *peer,
 420                        enum pex_event ev)
 421 {
 422         if (!network_pex_active(&net->pex))
 423                 return;
 424
 425         switch (ev) {
 426         case PEX_EV_HANDSHAKE:
 427                 peer->state.last_query_sent = 0;
 428                 pex_send_hello(net, peer);
 429                 if (net->config.type == NETWORK_TYPE_DYNAMIC)
 430                         network_pex_send_update_request(net, peer, NULL);
 431                 break;
 432         case PEX_EV_ENDPOINT_CHANGE:
 433                 network_pex_handle_endpoint_change(net, peer);
 434                 break;
 435         case PEX_EV_QUERY:
 436                 network_pex_query_hosts(net);
 437                 break;
 438         case PEX_EV_PING:
 439                 network_pex_send_ping(net, peer);
 440                 break;
 441         }
 442 }
 443
 444 static void
 445 network_pex_recv_hello(struct network *net, struct network_peer *peer,
 446                        const struct pex_hello *data, size_t len)
 447 {
 448         char addrstr[INET6_ADDRSTRLEN];
 449         uint16_t flags;
 450         int af;
 451
 452         if (len < sizeof(*data))
 453                 return;
 454
 455         if (peer->state.has_local_ep_addr &&
 456             !memcmp(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr)))
 457                 return;
 458
 459         flags = ntohs(data->flags);
 460         af = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 461         D_PEER(net, peer, "set local endpoint address to %s",
 462                inet_ntop(af, data->local_addr, addrstr, sizeof(addrstr)));
 463         peer->state.has_local_ep_addr = true;
 464         memcpy(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr));
 465 }
 466
 467 static void
 468 network_pex_recv_peers(struct network *net, struct network_peer *peer,
 469                        const struct pex_peer_endpoint *data, size_t len)
 470 {
 471         struct network_peer *local = &net->net_config.local_host->peer;
 472         struct network_peer *cur;
 473
 474         for (; len >= sizeof(*data); len -= sizeof(*data), data++) {
 475                 union network_endpoint *ep;
 476                 uint16_t flags;
 477                 void *addr;
 478                 int len;
 479
 480                 if (!memcmp(data->peer_id, &local->key, PEX_ID_LEN)) {
 481                         network_stun_update_port(net, false, ntohs(data->port));
 482                         continue;
 483                 }
 484
 485                 cur = pex_msg_peer(net, data->peer_id);
 486                 if (!cur || cur == peer)
 487                         continue;
 488
 489                 D_PEER(net, peer, "received peer address for %s",
 490                        network_peer_name(cur));
 491                 flags = ntohs(data->flags);
 492                 ep = &cur->state.next_endpoint[ENDPOINT_TYPE_PEX];
 493                 ep->sa.sa_family = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 494                 addr = network_endpoint_addr(ep, &len);
 495                 memcpy(addr, data->addr, len);
 496                 ep->in.sin_port = data->port;
 497         }
 498 }
 499
 500 static void
 501 network_pex_recv_query(struct network *net, struct network_peer *peer,
 502                        const uint8_t *data, size_t len)
 503 {
 504         struct network_peer *cur;
 505         int resp = 0;
 506
 507         pex_msg_init(net, PEX_MSG_NOTIFY_PEERS);
 508         for (; len >= 8; data += 8, len -= 8) {
 509                 cur = pex_msg_peer(net, data);
 510                 if (!cur || !cur->state.connected)
 511                         continue;
 512
 513                 if (!pex_msg_add_peer_endpoint(net, cur, peer))
 514                         resp++;
 515         }
 516
 517         if (!resp)
 518                 return;
 519
 520         D_PEER(net, peer, "send query response with %d hosts", resp);
 521         pex_msg_send(net, peer);
 522 }
 523
 524 static void
 525 network_pex_recv_ping(struct network *net, struct network_peer *peer)
 526 {
 527         time_t now = time(NULL);
 528
 529         if (peer->state.last_request == now)
 530                 return;
 531
 532         peer->state.last_request = now;
 533         pex_msg_init(net, PEX_MSG_PONG);
 534         pex_msg_send(net, peer);
 535 }
 536
 537 static void
 538 network_pex_recv_update_request(struct network *net, struct network_peer *peer,
 539                                 const uint8_t *data, size_t len,
 540                                 struct sockaddr_in6 *addr)
 541 {
 542         struct pex_update_request *req = (struct pex_update_request *)data;
 543         struct pex_msg_update_send_ctx ctx = {};
 544         uint64_t req_version = be64_to_cpu(req->cur_version);
 545         int *query_count;
 546         bool done = false;
 547
 548         if (len < sizeof(struct pex_update_request))
 549                 return;
 550
 551         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 552                 return;
 553
 554         if (peer)
 555                 query_count = &peer->state.num_net_queries;
 556         else
 557                 query_count = &net->num_net_queries;
 558
 559         if (++*query_count > 10)
 560                 return;
 561
 562         D("receive update request, local version=%"PRIu64", remote version=%"PRIu64, net->net_data_version, req_version);
 563
 564         if (req_version >= net->net_data_version) {
 565                 struct pex_update_response_no_data *res;
 566
 567                 pex_msg_init_ext(net, PEX_MSG_UPDATE_RESPONSE_NO_DATA, !!addr);
 568                 res = pex_msg_append(sizeof(*res));
 569                 res->req_id = req->req_id;
 570                 res->cur_version = cpu_to_be64(net->net_data_version);
 571                 pex_msg_send_ext(net, peer, addr);
 572         }
 573
 574         if (req_version > net->net_data_version)
 575                 network_pex_send_update_request(net, peer, addr);
 576
 577         if (!peer || !net->net_data_len)
 578                 return;
 579
 580         if (req_version >= net->net_data_version)
 581                 return;
 582
 583         pex_msg_update_response_init(&ctx, net->config.pubkey, net->config.auth_key,
 584                                      peer->key, !!addr, (void *)data,
 585                                      net->net_data, net->net_data_len);
 586         while (!done) {
 587                 pex_msg_send_ext(net, peer, addr);
 588                 done = !pex_msg_update_response_continue(&ctx);
 589         }
 590 }
 591
 592 static void
 593 network_pex_recv_update_response(struct network *net, const uint8_t *data, size_t len,
 594                               struct sockaddr_in6 *addr, enum pex_opcode op)
 595 {
 596         struct network_peer *peer;
 597         void *net_data;
 598         int net_data_len = 0;
 599         uint64_t version = 0;
 600         bool no_prev_data = !net->net_data_len;
 601
 602         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 603                 return;
 604
 605         net_data = pex_msg_update_response_recv(data, len, op, &net_data_len, &version);
 606         if (!net_data)
 607                 return;
 608
 609         if (version <= net->net_data_version) {
 610                 free(net_data);
 611                 return;
 612         }
 613
 614         D_NET(net, "received updated network data, len=%d", net_data_len);
 615         free(net->net_data);
 616
 617         net->net_data = net_data;
 618         net->net_data_len = net_data_len;
 619         net->net_data_version = version;
 620         if (network_save_dynamic(net) < 0)
 621                 return;
 622
 623         uloop_timeout_set(&net->reload_timer, no_prev_data ? 1 : UNETD_DATA_UPDATE_DELAY);
 624         vlist_for_each_element(&net->peers, peer, node) {
 625                 if (!peer->state.connected || !peer->pex_port)
 626                         continue;
 627                 network_pex_send_update_request(net, peer, NULL);
 628         }
 629 }
 630
 631 static void
 632 network_pex_recv(struct network *net, struct network_peer *peer, struct pex_hdr *hdr)
 633 {
 634         const void *data = hdr + 1;
 635
 636         if (hdr->version != 0)
 637                 return;
 638
 639         D_PEER(net, peer, "PEX rx op=%d", hdr->opcode);
 640         switch (hdr->opcode) {
 641         case PEX_MSG_HELLO:
 642                 network_pex_recv_hello(net, peer, data, hdr->len);
 643                 break;
 644         case PEX_MSG_NOTIFY_PEERS:
 645                 network_pex_recv_peers(net, peer, data, hdr->len);
 646                 break;
 647         case PEX_MSG_QUERY:
 648                 network_pex_recv_query(net, peer, data, hdr->len);
 649                 break;
 650         case PEX_MSG_PING:
 651                 network_pex_recv_ping(net, peer);
 652                 break;
 653         case PEX_MSG_PONG:
 654                 break;
 655         case PEX_MSG_UPDATE_REQUEST:
 656                 network_pex_recv_update_request(net, peer, data, hdr->len,
 657                                                 NULL);
 658                 break;
 659         case PEX_MSG_UPDATE_RESPONSE:
 660         case PEX_MSG_UPDATE_RESPONSE_DATA:
 661         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 662                 network_pex_recv_update_response(net, data, hdr->len,
 663                                               NULL, hdr->opcode);
 664                 break;
 665         case PEX_MSG_ENDPOINT_NOTIFY:
 666                 break;
 667         }
 668 }
 669
 670 static void
 671 network_pex_fd_cb(struct uloop_fd *fd, unsigned int events)
 672 {
 673         struct network *net = container_of(fd, struct network, pex.fd);
 674         struct network_peer *local = &net->net_config.local_host->peer;
 675         struct network_peer *peer;
 676         struct sockaddr_in6 sin6;
 677         static char buf[PEX_BUF_SIZE];
 678         struct pex_hdr *hdr = (struct pex_hdr *)buf;
 679         ssize_t len;
 680
 681         while (1) {
 682                 socklen_t slen = sizeof(sin6);
 683
 684                 len = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&sin6, &slen);
 685                 if (len < 0) {
 686                         if (errno == EINTR)
 687                                 continue;
 688
 689                         if (errno == EAGAIN)
 690                                 break;
 691
 692                         D_NET(net, "recvfrom failed: %s", strerror(errno));
 693                         network_pex_close(net);
 694                         return;
 695                 }
 696
 697                 if (!len)
 698                         continue;
 699
 700                 hdr = pex_rx_accept(buf, len, false);
 701                 if (!hdr)
 702                         continue;
 703
 704                 peer = pex_msg_peer(net, hdr->id);
 705                 if (!peer)
 706                         continue;
 707
 708                 if (memcmp(&sin6.sin6_addr, &peer->local_addr.in6, sizeof(sin6.sin6_addr)) != 0)
 709                         continue;
 710
 711                 if (peer == local)
 712                         continue;
 713
 714                 network_pex_recv(net, peer, hdr);
 715         }
 716 }
 717
 718 void network_pex_create_host(struct network *net, union network_endpoint *ep,
 719                              unsigned int timeout)
 720 {
 721         struct network_pex *pex = &net->pex;
 722         struct network_pex_host *host;
 723         uint64_t now = unet_gettime();
 724         bool new_host = false;
 725
 726         list_for_each_entry(host, &pex->hosts, list) {
 727                 if (memcmp(&host->endpoint, ep, sizeof(host->endpoint)) != 0)
 728                         continue;
 729
 730                 if (host->last_ping + 10 < now) {
 731                         list_move_tail(&host->list, &pex->hosts);
 732                         network_pex_host_request_update(net, host);
 733                 }
 734                 goto out;
 735         }
 736
 737         host = calloc(1, sizeof(*host));
 738         new_host = true;
 739         memcpy(&host->endpoint, ep, sizeof(host->endpoint));
 740         list_add_tail(&host->list, &pex->hosts);
 741         pex->num_hosts++;
 742
 743 out:
 744         if (timeout && (new_host || host->timeout))
 745                 host->timeout = timeout + unet_gettime();
 746 }
 747
 748 static void
 749 network_pex_open_auth_connect(struct network *net)
 750 {
 751         struct network_pex *pex = &net->pex;
 752         struct network_peer *peer;
 753         struct blob_attr *cur;
 754         int rem;
 755
 756         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 757                 return;
 758
 759         uloop_timeout_set(&pex->request_update_timer, 5000);
 760
 761         vlist_for_each_element(&net->peers, peer, node) {
 762                 union network_endpoint ep = {};
 763
 764                 if (!peer->endpoint || peer->dynamic)
 765                         continue;
 766
 767                 if (network_get_endpoint(&ep, AF_UNSPEC, peer->endpoint,
 768                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 769                         continue;
 770
 771                 ep.in.sin_port = htons(UNETD_GLOBAL_PEX_PORT);
 772                 network_pex_create_host(net, &ep, 0);
 773         }
 774
 775         if (!net->config.auth_connect)
 776                 return;
 777
 778         blobmsg_for_each_attr(cur, net->config.auth_connect, rem) {
 779                 union network_endpoint ep = {};
 780
 781                 if (network_get_endpoint(&ep, AF_UNSPEC, blobmsg_get_string(cur),
 782                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 783                         continue;
 784
 785                 network_pex_create_host(net, &ep, 0);
 786         }
 787 }
 788
 789
 790 int network_pex_open(struct network *net)
 791 {
 792         struct network_host *local_host = net->net_config.local_host;
 793         struct network_peer *local;
 794         struct network_pex *pex = &net->pex;
 795         struct sockaddr_in6 sin6 = {};
 796         int yes = 1;
 797         int fd;
 798
 799         network_pex_open_auth_connect(net);
 800
 801         if (!local_host || !local_host->peer.pex_port)
 802                 return 0;
 803
 804         local = &local_host->peer;
 805         fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 806         if (fd < 0)
 807                 return -1;
 808
 809         fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
 810         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
 811
 812         sin6.sin6_family = AF_INET6;
 813         memcpy(&sin6.sin6_addr, &local->local_addr.in6,
 814                sizeof(local->local_addr.in6));
 815         sin6.sin6_port = htons(local_host->peer.pex_port);
 816
 817         if (bind(fd, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
 818                 perror("bind");
 819                 goto close;
 820         }
 821
 822         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
 823         setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes));
 824 #ifdef linux
 825         setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
 826                    network_name(net), strlen(network_name(net)));
 827 #endif
 828
 829         pex->fd.fd = fd;
 830         pex->fd.cb = network_pex_fd_cb;
 831         uloop_fd_add(&pex->fd, ULOOP_READ);
 832
 833         return 0;
 834
 835 close:
 836         close(fd);
 837         return -1;
 838 }
 839
 840 void network_pex_close(struct network *net)
 841 {
 842         struct network_pex *pex = &net->pex;
 843         struct network_pex_host *host, *tmp;
 844         uint64_t now = unet_gettime();
 845
 846         uloop_timeout_cancel(&pex->request_update_timer);
 847         list_for_each_entry_safe(host, tmp, &pex->hosts, list) {
 848                 if (host->timeout)
 849                         continue;
 850
 851                 if (host->last_active + UNETD_PEX_HOST_ACITVE_TIMEOUT >= now)
 852                         continue;
 853
 854                 network_pex_free_host(net, host);
 855         }
 856
 857         if (pex->fd.fd < 0)
 858                 return;
 859
 860         uloop_fd_delete(&pex->fd);
 861         close(pex->fd.fd);
 862         network_pex_init(net);
 863 }
 864
 865 void network_pex_free(struct network *net)
 866 {
 867         struct network_pex *pex = &net->pex;
 868         struct network_pex_host *host, *tmp;
 869
 870         list_for_each_entry_safe(host, tmp, &pex->hosts, list)
 871                 network_pex_free_host(net, host);
 872 }
 873
 874 static struct network *
 875 global_pex_find_network(const uint8_t *id)
 876 {
 877         struct network *net;
 878
 879         avl_for_each_element(&networks, net, node) {
 880                 if (!memcmp(id, net->config.auth_key, PEX_ID_LEN))
 881                         return net;
 882         }
 883
 884         return NULL;
 885 }
 886
 887 static void
 888 global_pex_set_active(struct network *net, struct sockaddr_in6 *addr)
 889 {
 890         struct network_pex *pex = &net->pex;
 891         struct network_pex_host *host;
 892
 893         list_for_each_entry(host, &pex->hosts, list) {
 894                 if (memcmp(&host->endpoint.in6, addr, sizeof(*addr)) != 0)
 895                         continue;
 896
 897                 host->last_active = unet_gettime();
 898         }
 899 }
 900
 901 static void
 902 global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 903 {
 904         struct pex_hdr *hdr;
 905         struct pex_ext_hdr *ehdr;
 906         struct network_peer *peer;
 907         struct network *net;
 908         char buf[INET6_ADDRSTRLEN];
 909         void *data;
 910         int addr_len;
 911         int ep_idx = ENDPOINT_TYPE_ENDPOINT_NOTIFY;
 912
 913         if (stun_msg_is_valid(msg, msg_len)) {
 914                 avl_for_each_element(&networks, net, node)
 915                         network_stun_rx_packet(net, msg, msg_len);
 916         }
 917
 918         hdr = pex_rx_accept(msg, msg_len, true);
 919         if (!hdr)
 920                 return;
 921
 922         ehdr = (void *)(hdr + 1);
 923         data = (void *)(ehdr + 1);
 924
 925         if (hdr->version != 0)
 926                 return;
 927
 928         net = global_pex_find_network(ehdr->auth_id);
 929         if (!net || net->config.type != NETWORK_TYPE_DYNAMIC)
 930                 return;
 931
 932         *(uint64_t *)hdr->id ^= pex_network_hash(net->config.auth_key, ehdr->nonce);
 933
 934         global_pex_set_active(net, addr);
 935
 936         D("PEX global rx op=%d", hdr->opcode);
 937         switch (hdr->opcode) {
 938         case PEX_MSG_HELLO:
 939         case PEX_MSG_NOTIFY_PEERS:
 940         case PEX_MSG_QUERY:
 941         case PEX_MSG_PING:
 942         case PEX_MSG_PONG:
 943                 break;
 944         case PEX_MSG_UPDATE_REQUEST:
 945                 peer = pex_msg_peer(net, hdr->id);
 946                 network_pex_recv_update_request(net, peer, data, hdr->len,
 947                                                 addr);
 948                 break;
 949         case PEX_MSG_UPDATE_RESPONSE:
 950         case PEX_MSG_UPDATE_RESPONSE_DATA:
 951         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 952                 network_pex_recv_update_response(net, data, hdr->len, addr, hdr->opcode);
 953                 break;
 954         case PEX_MSG_ENDPOINT_PORT_NOTIFY:
 955                 if (hdr->len < sizeof(struct pex_endpoint_port_notify))
 956                         break;
 957
 958                 ep_idx = ENDPOINT_TYPE_ENDPOINT_PORT_NOTIFY;
 959                 fallthrough;
 960         case PEX_MSG_ENDPOINT_NOTIFY:
 961                 peer = pex_msg_peer(net, hdr->id);
 962                 if (!peer)
 963                         break;
 964
 965                 D_PEER(net, peer, "receive endpoint notification from %s",
 966                   inet_ntop(addr->sin6_family, network_endpoint_addr((void *)addr, &addr_len),
 967                             buf, sizeof(buf)));
 968
 969                 memcpy(&peer->state.next_endpoint[ep_idx], addr, sizeof(*addr));
 970                 if (hdr->opcode == PEX_MSG_ENDPOINT_PORT_NOTIFY) {
 971                         struct pex_endpoint_port_notify *port = data;
 972                         union network_endpoint host_ep = {
 973                                 .in6 = *addr
 974                         };
 975
 976                         peer->state.next_endpoint[ep_idx].in.sin_port = port->port;
 977                         if (net->pex.num_hosts < NETWORK_PEX_HOSTS_LIMIT)
 978                                 network_pex_create_host(net, &host_ep, 120);
 979                 }
 980                 break;
 981         }
 982 }
 983
 984 static void
 985 pex_recv_control(struct pex_msg_local_control *msg, int len)
 986 {
 987         struct network *net;
 988
 989         if (msg->msg_type != 0)
 990                 return;
 991
 992         net = global_pex_find_network(msg->auth_id);
 993         if (!net)
 994                 return;
 995
 996         if (!msg->timeout)
 997                 msg->timeout = 60;
 998         network_pex_create_host(net, &msg->ep, msg->timeout);
 999 }
1000
1001 int global_pex_open(const char *unix_path)
1002 {
1003         struct sockaddr_in6 sin6 = {};
1004         int ret;
1005
1006         sin6.sin6_family = AF_INET6;
1007         sin6.sin6_port = htons(global_pex_port);
1008
1009         ret = pex_open(&sin6, sizeof(sin6), global_pex_recv, true);
1010
1011         if (unix_path)
1012                 pex_unix_open(unix_path, pex_recv_control);
1013
1014         return ret;
1015 }