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                         peer->state.last_query_sent = now;
 380                         return;
 381                 }
 382         }
 383
 384 }
 385
 386 static void
 387 network_pex_send_ping(struct network *net, struct network_peer *peer)
 388 {
 389         if (peer->state.pinged || !peer->state.endpoint.sa.sa_family)
 390                 return;
 391
 392         pex_msg_init(net, PEX_MSG_PING);
 393         pex_msg_send(net, peer);
 394         peer->state.pinged = true;
 395 }
 396
 397 static void
 398 network_pex_send_update_request(struct network *net, struct network_peer *peer,
 399                                 struct sockaddr_in6 *addr)
 400 {
 401         union network_endpoint ep = {};
 402         uint64_t version = 0;
 403
 404         if (addr)
 405                 memcpy(&ep.in6, addr, sizeof(ep.in6));
 406         else
 407                 pex_get_peer_addr(&ep.in6, net, peer);
 408
 409         if (net->net_data_len)
 410                 version = net->net_data_version;
 411
 412         if (!pex_msg_update_request_init(net->config.pubkey, net->config.key,
 413                                          net->config.auth_key, &ep,
 414                                          version, !!addr))
 415                 return;
 416
 417         pex_msg_send_ext(net, peer, addr);
 418 }
 419
 420 void network_pex_event(struct network *net, struct network_peer *peer,
 421                        enum pex_event ev)
 422 {
 423         if (!network_pex_active(&net->pex))
 424                 return;
 425
 426         switch (ev) {
 427         case PEX_EV_HANDSHAKE:
 428                 peer->state.last_query_sent = 0;
 429                 pex_send_hello(net, peer);
 430                 if (net->config.type == NETWORK_TYPE_DYNAMIC)
 431                         network_pex_send_update_request(net, peer, NULL);
 432                 break;
 433         case PEX_EV_ENDPOINT_CHANGE:
 434                 network_pex_handle_endpoint_change(net, peer);
 435                 break;
 436         case PEX_EV_QUERY:
 437                 network_pex_query_hosts(net);
 438                 break;
 439         case PEX_EV_PING:
 440                 network_pex_send_ping(net, peer);
 441                 break;
 442         }
 443 }
 444
 445 static void
 446 network_pex_recv_hello(struct network *net, struct network_peer *peer,
 447                        const struct pex_hello *data, size_t len)
 448 {
 449         char addrstr[INET6_ADDRSTRLEN];
 450         uint16_t flags;
 451         int af;
 452
 453         if (len < sizeof(*data))
 454                 return;
 455
 456         if (peer->state.has_local_ep_addr &&
 457             !memcmp(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr)))
 458                 return;
 459
 460         flags = ntohs(data->flags);
 461         af = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 462         D_PEER(net, peer, "set local endpoint address to %s",
 463                inet_ntop(af, data->local_addr, addrstr, sizeof(addrstr)));
 464         peer->state.has_local_ep_addr = true;
 465         memcpy(&peer->state.local_ep_addr, data->local_addr, sizeof(data->local_addr));
 466 }
 467
 468 static void
 469 network_pex_recv_peers(struct network *net, struct network_peer *peer,
 470                        const struct pex_peer_endpoint *data, size_t len)
 471 {
 472         struct network_peer *local = &net->net_config.local_host->peer;
 473         struct network_peer *cur;
 474
 475         for (; len >= sizeof(*data); len -= sizeof(*data), data++) {
 476                 union network_endpoint *ep;
 477                 uint16_t flags;
 478                 void *addr;
 479                 int len;
 480
 481                 if (!memcmp(data->peer_id, &local->key, PEX_ID_LEN)) {
 482                         network_stun_update_port(net, false, ntohs(data->port));
 483                         continue;
 484                 }
 485
 486                 cur = pex_msg_peer(net, data->peer_id);
 487                 if (!cur || cur == peer)
 488                         continue;
 489
 490                 D_PEER(net, peer, "received peer address for %s",
 491                        network_peer_name(cur));
 492                 flags = ntohs(data->flags);
 493                 ep = &cur->state.next_endpoint[ENDPOINT_TYPE_PEX];
 494                 ep->sa.sa_family = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 495                 addr = network_endpoint_addr(ep, &len);
 496                 memcpy(addr, data->addr, len);
 497                 ep->in.sin_port = data->port;
 498         }
 499 }
 500
 501 static void
 502 network_pex_recv_query(struct network *net, struct network_peer *peer,
 503                        const uint8_t *data, size_t len)
 504 {
 505         struct network_peer *cur;
 506         int resp = 0;
 507
 508         pex_msg_init(net, PEX_MSG_NOTIFY_PEERS);
 509         for (; len >= 8; data += 8, len -= 8) {
 510                 cur = pex_msg_peer(net, data);
 511                 if (!cur || !cur->state.connected)
 512                         continue;
 513
 514                 if (!pex_msg_add_peer_endpoint(net, cur, peer))
 515                         resp++;
 516         }
 517
 518         if (!resp)
 519                 return;
 520
 521         D_PEER(net, peer, "send query response with %d hosts", resp);
 522         pex_msg_send(net, peer);
 523 }
 524
 525 static void
 526 network_pex_recv_ping(struct network *net, struct network_peer *peer)
 527 {
 528         time_t now = time(NULL);
 529
 530         if (peer->state.last_request == now)
 531                 return;
 532
 533         peer->state.last_request = now;
 534         pex_msg_init(net, PEX_MSG_PONG);
 535         pex_msg_send(net, peer);
 536 }
 537
 538 static void
 539 network_pex_recv_update_request(struct network *net, struct network_peer *peer,
 540                                 const uint8_t *data, size_t len,
 541                                 struct sockaddr_in6 *addr)
 542 {
 543         struct pex_update_request *req = (struct pex_update_request *)data;
 544         struct pex_msg_update_send_ctx ctx = {};
 545         uint64_t req_version = be64_to_cpu(req->cur_version);
 546         int *query_count;
 547         bool done = false;
 548
 549         if (len < sizeof(struct pex_update_request))
 550                 return;
 551
 552         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 553                 return;
 554
 555         if (peer)
 556                 query_count = &peer->state.num_net_queries;
 557         else
 558                 query_count = &net->num_net_queries;
 559
 560         if (++*query_count > 10)
 561                 return;
 562
 563         D("receive update request, local version=%"PRIu64", remote version=%"PRIu64, net->net_data_version, req_version);
 564
 565         if (req_version >= net->net_data_version) {
 566                 struct pex_update_response_no_data *res;
 567
 568                 pex_msg_init_ext(net, PEX_MSG_UPDATE_RESPONSE_NO_DATA, !!addr);
 569                 res = pex_msg_append(sizeof(*res));
 570                 res->req_id = req->req_id;
 571                 res->cur_version = cpu_to_be64(net->net_data_version);
 572                 pex_msg_send_ext(net, peer, addr);
 573         }
 574
 575         if (req_version > net->net_data_version)
 576                 network_pex_send_update_request(net, peer, addr);
 577
 578         if (!peer || !net->net_data_len)
 579                 return;
 580
 581         if (req_version >= net->net_data_version)
 582                 return;
 583
 584         pex_msg_update_response_init(&ctx, net->config.pubkey, net->config.auth_key,
 585                                      peer->key, !!addr, (void *)data,
 586                                      net->net_data, net->net_data_len);
 587         while (!done) {
 588                 pex_msg_send_ext(net, peer, addr);
 589                 done = !pex_msg_update_response_continue(&ctx);
 590         }
 591 }
 592
 593 static void
 594 network_pex_recv_update_response(struct network *net, const uint8_t *data, size_t len,
 595                               struct sockaddr_in6 *addr, enum pex_opcode op)
 596 {
 597         struct network_peer *peer;
 598         void *net_data;
 599         int net_data_len = 0;
 600         uint64_t version = 0;
 601         bool no_prev_data = !net->net_data_len;
 602
 603         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 604                 return;
 605
 606         net_data = pex_msg_update_response_recv(data, len, op, &net_data_len, &version);
 607         if (!net_data)
 608                 return;
 609
 610         if (version <= net->net_data_version) {
 611                 free(net_data);
 612                 return;
 613         }
 614
 615         D_NET(net, "received updated network data, len=%d", net_data_len);
 616         free(net->net_data);
 617
 618         net->net_data = net_data;
 619         net->net_data_len = net_data_len;
 620         net->net_data_version = version;
 621         if (network_save_dynamic(net) < 0)
 622                 return;
 623
 624         uloop_timeout_set(&net->reload_timer, no_prev_data ? 1 : UNETD_DATA_UPDATE_DELAY);
 625         vlist_for_each_element(&net->peers, peer, node) {
 626                 if (!peer->state.connected || !peer->pex_port)
 627                         continue;
 628                 network_pex_send_update_request(net, peer, NULL);
 629         }
 630 }
 631
 632 static void
 633 network_pex_recv(struct network *net, struct network_peer *peer, struct pex_hdr *hdr)
 634 {
 635         const void *data = hdr + 1;
 636
 637         if (hdr->version != 0)
 638                 return;
 639
 640         D_PEER(net, peer, "PEX rx op=%d", hdr->opcode);
 641         switch (hdr->opcode) {
 642         case PEX_MSG_HELLO:
 643                 network_pex_recv_hello(net, peer, data, hdr->len);
 644                 break;
 645         case PEX_MSG_NOTIFY_PEERS:
 646                 network_pex_recv_peers(net, peer, data, hdr->len);
 647                 break;
 648         case PEX_MSG_QUERY:
 649                 network_pex_recv_query(net, peer, data, hdr->len);
 650                 break;
 651         case PEX_MSG_PING:
 652                 network_pex_recv_ping(net, peer);
 653                 break;
 654         case PEX_MSG_PONG:
 655                 break;
 656         case PEX_MSG_UPDATE_REQUEST:
 657                 network_pex_recv_update_request(net, peer, data, hdr->len,
 658                                                 NULL);
 659                 break;
 660         case PEX_MSG_UPDATE_RESPONSE:
 661         case PEX_MSG_UPDATE_RESPONSE_DATA:
 662         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 663                 network_pex_recv_update_response(net, data, hdr->len,
 664                                               NULL, hdr->opcode);
 665                 break;
 666         case PEX_MSG_ENDPOINT_NOTIFY:
 667                 break;
 668         }
 669 }
 670
 671 static void
 672 network_pex_fd_cb(struct uloop_fd *fd, unsigned int events)
 673 {
 674         struct network *net = container_of(fd, struct network, pex.fd);
 675         struct network_peer *local = &net->net_config.local_host->peer;
 676         struct network_peer *peer;
 677         struct sockaddr_in6 sin6;
 678         static char buf[PEX_BUF_SIZE];
 679         struct pex_hdr *hdr = (struct pex_hdr *)buf;
 680         ssize_t len;
 681
 682         while (1) {
 683                 socklen_t slen = sizeof(sin6);
 684
 685                 len = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&sin6, &slen);
 686                 if (len < 0) {
 687                         if (errno == EINTR)
 688                                 continue;
 689
 690                         if (errno == EAGAIN)
 691                                 break;
 692
 693                         D_NET(net, "recvfrom failed: %s", strerror(errno));
 694                         network_pex_close(net);
 695                         return;
 696                 }
 697
 698                 if (!len)
 699                         continue;
 700
 701                 hdr = pex_rx_accept(buf, len, false);
 702                 if (!hdr)
 703                         continue;
 704
 705                 peer = pex_msg_peer(net, hdr->id);
 706                 if (!peer)
 707                         continue;
 708
 709                 if (memcmp(&sin6.sin6_addr, &peer->local_addr.in6, sizeof(sin6.sin6_addr)) != 0)
 710                         continue;
 711
 712                 if (peer == local)
 713                         continue;
 714
 715                 network_pex_recv(net, peer, hdr);
 716         }
 717 }
 718
 719 void network_pex_create_host(struct network *net, union network_endpoint *ep,
 720                              unsigned int timeout)
 721 {
 722         struct network_pex *pex = &net->pex;
 723         struct network_pex_host *host;
 724         uint64_t now = unet_gettime();
 725         bool new_host = false;
 726
 727         list_for_each_entry(host, &pex->hosts, list) {
 728                 if (memcmp(&host->endpoint, ep, sizeof(host->endpoint)) != 0)
 729                         continue;
 730
 731                 if (host->last_ping + 10 < now) {
 732                         list_move_tail(&host->list, &pex->hosts);
 733                         network_pex_host_request_update(net, host);
 734                 }
 735                 goto out;
 736         }
 737
 738         host = calloc(1, sizeof(*host));
 739         new_host = true;
 740         memcpy(&host->endpoint, ep, sizeof(host->endpoint));
 741         list_add_tail(&host->list, &pex->hosts);
 742         pex->num_hosts++;
 743
 744 out:
 745         if (timeout && (new_host || host->timeout))
 746                 host->timeout = timeout + unet_gettime();
 747 }
 748
 749 static void
 750 network_pex_open_auth_connect(struct network *net)
 751 {
 752         struct network_pex *pex = &net->pex;
 753         struct network_peer *peer;
 754         struct blob_attr *cur;
 755         int rem;
 756
 757         if (net->config.type != NETWORK_TYPE_DYNAMIC)
 758                 return;
 759
 760         uloop_timeout_set(&pex->request_update_timer, 5000);
 761
 762         vlist_for_each_element(&net->peers, peer, node) {
 763                 union network_endpoint ep = {};
 764
 765                 if (!peer->endpoint || peer->dynamic)
 766                         continue;
 767
 768                 if (network_get_endpoint(&ep, AF_UNSPEC, peer->endpoint,
 769                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 770                         continue;
 771
 772                 ep.in.sin_port = htons(UNETD_GLOBAL_PEX_PORT);
 773                 network_pex_create_host(net, &ep, 0);
 774         }
 775
 776         if (!net->config.auth_connect)
 777                 return;
 778
 779         blobmsg_for_each_attr(cur, net->config.auth_connect, rem) {
 780                 union network_endpoint ep = {};
 781
 782                 if (network_get_endpoint(&ep, AF_UNSPEC, blobmsg_get_string(cur),
 783                                          UNETD_GLOBAL_PEX_PORT, 0) < 0)
 784                         continue;
 785
 786                 network_pex_create_host(net, &ep, 0);
 787         }
 788 }
 789
 790
 791 int network_pex_open(struct network *net)
 792 {
 793         struct network_host *local_host = net->net_config.local_host;
 794         struct network_peer *local;
 795         struct network_pex *pex = &net->pex;
 796         struct sockaddr_in6 sin6 = {};
 797         int yes = 1;
 798         int fd;
 799
 800         network_pex_open_auth_connect(net);
 801
 802         if (!local_host || !local_host->peer.pex_port)
 803                 return 0;
 804
 805         local = &local_host->peer;
 806         fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 807         if (fd < 0)
 808                 return -1;
 809
 810         fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
 811         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
 812
 813         sin6.sin6_family = AF_INET6;
 814         memcpy(&sin6.sin6_addr, &local->local_addr.in6,
 815                sizeof(local->local_addr.in6));
 816         sin6.sin6_port = htons(local_host->peer.pex_port);
 817
 818         if (bind(fd, (struct sockaddr *)&sin6, sizeof(sin6)) < 0) {
 819                 perror("bind");
 820                 goto close;
 821         }
 822
 823         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
 824         setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes));
 825 #ifdef linux
 826         setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
 827                    network_name(net), strlen(network_name(net)));
 828 #endif
 829
 830         pex->fd.fd = fd;
 831         pex->fd.cb = network_pex_fd_cb;
 832         uloop_fd_add(&pex->fd, ULOOP_READ);
 833
 834         return 0;
 835
 836 close:
 837         close(fd);
 838         return -1;
 839 }
 840
 841 void network_pex_close(struct network *net)
 842 {
 843         struct network_pex *pex = &net->pex;
 844         struct network_pex_host *host, *tmp;
 845         uint64_t now = unet_gettime();
 846
 847         uloop_timeout_cancel(&pex->request_update_timer);
 848         list_for_each_entry_safe(host, tmp, &pex->hosts, list) {
 849                 if (host->timeout)
 850                         continue;
 851
 852                 if (host->last_active + UNETD_PEX_HOST_ACITVE_TIMEOUT >= now)
 853                         continue;
 854
 855                 network_pex_free_host(net, host);
 856         }
 857
 858         if (pex->fd.fd < 0)
 859                 return;
 860
 861         uloop_fd_delete(&pex->fd);
 862         close(pex->fd.fd);
 863         network_pex_init(net);
 864 }
 865
 866 void network_pex_free(struct network *net)
 867 {
 868         struct network_pex *pex = &net->pex;
 869         struct network_pex_host *host, *tmp;
 870
 871         list_for_each_entry_safe(host, tmp, &pex->hosts, list)
 872                 network_pex_free_host(net, host);
 873 }
 874
 875 static struct network *
 876 global_pex_find_network(const uint8_t *id)
 877 {
 878         struct network *net;
 879
 880         avl_for_each_element(&networks, net, node) {
 881                 if (!memcmp(id, net->config.auth_key, PEX_ID_LEN))
 882                         return net;
 883         }
 884
 885         return NULL;
 886 }
 887
 888 static void
 889 global_pex_set_active(struct network *net, struct sockaddr_in6 *addr)
 890 {
 891         struct network_pex *pex = &net->pex;
 892         struct network_pex_host *host;
 893
 894         list_for_each_entry(host, &pex->hosts, list) {
 895                 if (memcmp(&host->endpoint.in6, addr, sizeof(*addr)) != 0)
 896                         continue;
 897
 898                 host->last_active = unet_gettime();
 899         }
 900 }
 901
 902 static void
 903 global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 904 {
 905         struct pex_hdr *hdr;
 906         struct pex_ext_hdr *ehdr;
 907         struct network_peer *peer;
 908         struct network *net;
 909         char buf[INET6_ADDRSTRLEN];
 910         void *data;
 911         int addr_len;
 912         int ep_idx = ENDPOINT_TYPE_ENDPOINT_NOTIFY;
 913
 914         if (stun_msg_is_valid(msg, msg_len)) {
 915                 avl_for_each_element(&networks, net, node)
 916                         network_stun_rx_packet(net, msg, msg_len);
 917         }
 918
 919         hdr = pex_rx_accept(msg, msg_len, true);
 920         if (!hdr)
 921                 return;
 922
 923         ehdr = (void *)(hdr + 1);
 924         data = (void *)(ehdr + 1);
 925
 926         if (hdr->version != 0)
 927                 return;
 928
 929         net = global_pex_find_network(ehdr->auth_id);
 930         if (!net || net->config.type != NETWORK_TYPE_DYNAMIC)
 931                 return;
 932
 933         *(uint64_t *)hdr->id ^= pex_network_hash(net->config.auth_key, ehdr->nonce);
 934
 935         global_pex_set_active(net, addr);
 936
 937         D("PEX global rx op=%d", hdr->opcode);
 938         switch (hdr->opcode) {
 939         case PEX_MSG_HELLO:
 940         case PEX_MSG_NOTIFY_PEERS:
 941         case PEX_MSG_QUERY:
 942         case PEX_MSG_PING:
 943         case PEX_MSG_PONG:
 944                 break;
 945         case PEX_MSG_UPDATE_REQUEST:
 946                 peer = pex_msg_peer(net, hdr->id);
 947                 network_pex_recv_update_request(net, peer, data, hdr->len,
 948                                                 addr);
 949                 break;
 950         case PEX_MSG_UPDATE_RESPONSE:
 951         case PEX_MSG_UPDATE_RESPONSE_DATA:
 952         case PEX_MSG_UPDATE_RESPONSE_NO_DATA:
 953                 network_pex_recv_update_response(net, data, hdr->len, addr, hdr->opcode);
 954                 break;
 955         case PEX_MSG_ENDPOINT_PORT_NOTIFY:
 956                 if (hdr->len < sizeof(struct pex_endpoint_port_notify))
 957                         break;
 958
 959                 ep_idx = ENDPOINT_TYPE_ENDPOINT_PORT_NOTIFY;
 960                 fallthrough;
 961         case PEX_MSG_ENDPOINT_NOTIFY:
 962                 peer = pex_msg_peer(net, hdr->id);
 963                 if (!peer)
 964                         break;
 965
 966                 D_PEER(net, peer, "receive endpoint notification from %s",
 967                   inet_ntop(addr->sin6_family, network_endpoint_addr((void *)addr, &addr_len),
 968                             buf, sizeof(buf)));
 969
 970                 memcpy(&peer->state.next_endpoint[ep_idx], addr, sizeof(*addr));
 971                 if (hdr->opcode == PEX_MSG_ENDPOINT_PORT_NOTIFY) {
 972                         struct pex_endpoint_port_notify *port = data;
 973                         union network_endpoint host_ep = {
 974                                 .in6 = *addr
 975                         };
 976
 977                         peer->state.next_endpoint[ep_idx].in.sin_port = port->port;
 978                         if (net->pex.num_hosts < NETWORK_PEX_HOSTS_LIMIT)
 979                                 network_pex_create_host(net, &host_ep, 120);
 980                 }
 981                 break;
 982         }
 983 }
 984
 985 static void
 986 pex_recv_control(struct pex_msg_local_control *msg, int len)
 987 {
 988         struct network *net;
 989
 990         if (msg->msg_type != 0)
 991                 return;
 992
 993         net = global_pex_find_network(msg->auth_id);
 994         if (!net)
 995                 return;
 996
 997         if (!msg->timeout)
 998                 msg->timeout = 60;
 999         network_pex_create_host(net, &msg->ep, msg->timeout);
1000 }
1001
1002 int global_pex_open(const char *unix_path)
1003 {
1004         struct sockaddr_in6 sin6 = {};
1005         int ret;
1006
1007         sin6.sin6_family = AF_INET6;
1008         sin6.sin6_port = htons(global_pex_port);
1009
1010         ret = pex_open(&sin6, sizeof(sin6), global_pex_recv, true);
1011
1012         if (unix_path)
1013                 pex_unix_open(unix_path, pex_recv_control);
1014
1015         return ret;
1016 }