git.meshlink.io Git - meshlink/blob - src/discovery.c

   1 #include "system.h"
   2
   3 #include <catta/core.h>
   4 #include <catta/lookup.h>
   5 #include <catta/publish.h>
   6 #include <catta/log.h>
   7 #include <catta/simple-watch.h>
   8 #include <catta/malloc.h>
   9 #include <catta/alternative.h>
  10 #include <catta/error.h>
  11
  12 #if defined(__APPLE__) || defined(__unix) && !defined(__linux)
  13 #include <net/route.h>
  14 #elif defined(__linux)
  15 #include <asm/types.h>
  16 #include <net/if.h>
  17 #include <linux/if_link.h>
  18 #include <linux/netlink.h>
  19 #include <linux/rtnetlink.h>
  20 #endif
  21
  22 #include "meshlink_internal.h"
  23 #include "event.h"
  24 #include "discovery.h"
  25 #include "sockaddr.h"
  26 #include "logger.h"
  27 #include "node.h"
  28 #include "connection.h"
  29 #include "xalloc.h"
  30
  31 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  32 #define MESHLINK_MDNS_NAME_KEY "name"
  33 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  34
  35 static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
  36         assert(size);
  37
  38         for(size_t i = 0; i < (size - 1); ++i) {
  39                 buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
  40         }
  41
  42         buffer[size - 1] = '\0';
  43 }
  44
  45 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  46         (void)server;
  47         (void)group;
  48         meshlink_handle_t *mesh = userdata;
  49
  50         assert(mesh);
  51         assert(mesh->catta_server);
  52         assert(mesh->catta_poll);
  53
  54         /* Called whenever the entry group state changes */
  55         switch(state) {
  56         case CATTA_ENTRY_GROUP_ESTABLISHED:
  57                 /* The entry group has been established successfully */
  58                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  59                 break;
  60
  61         case CATTA_ENTRY_GROUP_COLLISION:
  62                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  63                 // @TODO can we just set a new name and retry?
  64                 break;
  65
  66         case CATTA_ENTRY_GROUP_FAILURE :
  67                 /* Some kind of failure happened while we were registering our services */
  68                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  69                 catta_simple_poll_quit(mesh->catta_poll);
  70                 break;
  71
  72         case CATTA_ENTRY_GROUP_UNCOMMITED:
  73         case CATTA_ENTRY_GROUP_REGISTERING:
  74                 break;
  75         }
  76 }
  77
  78
  79 static void discovery_create_services(meshlink_handle_t *mesh) {
  80         char *fingerprint = NULL;
  81         char *txt_name = NULL;
  82         char *txt_fingerprint = NULL;
  83
  84         assert(mesh);
  85         assert(mesh->name);
  86         assert(mesh->myport);
  87         assert(mesh->catta_server);
  88         assert(mesh->catta_poll);
  89         assert(mesh->catta_servicetype);
  90         assert(mesh->self);
  91
  92         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  93
  94         /* Ifthis is the first time we're called, let's create a new entry group */
  95         if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  96                 logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  97                 goto fail;
  98         }
  99
 100         /* Create txt records */
 101         fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
 102         xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
 103         xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
 104
 105         /* Add the service */
 106         int ret = 0;
 107
 108         if((ret = catta_server_add_service(mesh->catta_server, mesh->catta_group, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, 0, fingerprint, mesh->catta_servicetype, NULL, NULL, atoi(mesh->myport), txt_name, txt_fingerprint, NULL)) < 0) {
 109                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 110                 goto fail;
 111         }
 112
 113         /* Tell the server to register the service */
 114         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 115                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 116                 goto fail;
 117         }
 118
 119         goto done;
 120
 121 fail:
 122         catta_simple_poll_quit(mesh->catta_poll);
 123
 124 done:
 125         free(fingerprint);
 126         free(txt_name);
 127         free(txt_fingerprint);
 128 }
 129
 130 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 131         (void)server;
 132         meshlink_handle_t *mesh = userdata;
 133
 134         assert(mesh);
 135
 136         switch(state) {
 137         case CATTA_SERVER_RUNNING:
 138
 139                 /* The serve has startup successfully and registered its host
 140                  * name on the network, so it's time to create our services */
 141                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 142                         abort();
 143                 }
 144
 145                 if(!mesh->catta_group) {
 146                         discovery_create_services(mesh);
 147                 }
 148
 149                 pthread_mutex_unlock(&mesh->mutex);
 150
 151                 break;
 152
 153         case CATTA_SERVER_COLLISION: {
 154                 /* A host name collision happened. Let's pick a new name for the server */
 155                 char hostname[17];
 156                 generate_rand_string(mesh, hostname, sizeof(hostname));
 157
 158                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 159                         abort();
 160                 }
 161
 162                 assert(mesh->catta_server);
 163                 assert(mesh->catta_poll);
 164
 165                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 166
 167                 if(result < 0) {
 168                         catta_simple_poll_quit(mesh->catta_poll);
 169                 }
 170
 171                 pthread_mutex_unlock(&mesh->mutex);
 172         }
 173         break;
 174
 175         case CATTA_SERVER_REGISTERING:
 176                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 177                         abort();
 178                 }
 179
 180                 /* Let's drop our registered services. When the server is back
 181                  * in CATTA_SERVER_RUNNING state we will register them
 182                  * again with the new host name. */
 183                 if(mesh->catta_group) {
 184                         catta_s_entry_group_reset(mesh->catta_group);
 185                         mesh->catta_group = NULL;
 186                 }
 187
 188                 pthread_mutex_unlock(&mesh->mutex);
 189
 190                 break;
 191
 192         case CATTA_SERVER_FAILURE:
 193                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 194                         abort();
 195                 }
 196
 197                 assert(mesh->catta_server);
 198                 assert(mesh->catta_poll);
 199
 200                 /* Terminate on failure */
 201                 catta_simple_poll_quit(mesh->catta_poll);
 202
 203                 pthread_mutex_unlock(&mesh->mutex);
 204                 break;
 205
 206         case CATTA_SERVER_INVALID:
 207                 break;
 208         }
 209 }
 210
 211 static void discovery_resolve_callback(CattaSServiceResolver *resolver, CattaIfIndex interface_, CattaProtocol protocol, CattaResolverEvent event, const char *name, const char *type, const char *domain, const char *host_name, const CattaAddress *address, uint16_t port, CattaStringList *txt, CattaLookupResultFlags flags, void *userdata) {
 212         (void)interface_;
 213         (void)protocol;
 214         (void)flags;
 215         (void)name;
 216         (void)type;
 217         (void)domain;
 218         (void)host_name;
 219
 220         meshlink_handle_t *mesh = userdata;
 221
 222         assert(mesh);
 223
 224         if(event != CATTA_RESOLVER_FOUND) {
 225                 catta_s_service_resolver_free(resolver);
 226                 return;
 227         }
 228
 229         // retrieve fingerprint
 230         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 231         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 232
 233         if(node_name_li && node_fp_li) {
 234                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 235                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 236
 237                 if(node_name[0] == '=' && node_fp[0] == '=') {
 238                         if(pthread_mutex_lock(&mesh->mutex) != 0) {
 239                                 abort();
 240                         }
 241
 242                         node_name += 1;
 243
 244                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 245
 246                         if(node) {
 247                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 248
 249                                 sockaddr_t naddress;
 250                                 memset(&naddress, 0, sizeof(naddress));
 251
 252                                 switch(address->proto) {
 253                                 case CATTA_PROTO_INET: {
 254                                         naddress.in.sin_family = AF_INET;
 255                                         naddress.in.sin_port = htons(port);
 256                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 257                                 }
 258                                 break;
 259
 260                                 case CATTA_PROTO_INET6: {
 261                                         naddress.in6.sin6_family = AF_INET6;
 262                                         naddress.in6.sin6_port = htons(port);
 263                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 264                                 }
 265                                 break;
 266
 267                                 default:
 268                                         naddress.unknown.family = AF_UNKNOWN;
 269                                         break;
 270                                 }
 271
 272                                 if(naddress.unknown.family != AF_UNKNOWN) {
 273                                         node_t *n = (node_t *)node;
 274                                         connection_t *c = n->connection;
 275
 276                                         n->catta_address = naddress;
 277                                         node_add_recent_address(mesh, n, &naddress);
 278
 279                                         if(c && c->outgoing && !c->status.active) {
 280                                                 c->outgoing->timeout = 0;
 281
 282                                                 if(c->outgoing->ev.cb) {
 283                                                         timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
 284                                                                 0, 0
 285                                                         });
 286                                                 }
 287
 288                                                 c->last_ping_time = -3600;
 289                                         }
 290
 291                                 } else {
 292                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 293                                 }
 294                         } else {
 295                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 296                         }
 297
 298                         pthread_mutex_unlock(&mesh->mutex);
 299                 }
 300         }
 301
 302         catta_s_service_resolver_free(resolver);
 303 }
 304
 305 static void discovery_browse_callback(CattaSServiceBrowser *browser, CattaIfIndex interface_, CattaProtocol protocol, CattaBrowserEvent event, const char *name, const char *type, const char *domain, CattaLookupResultFlags flags, void *userdata) {
 306         (void)browser;
 307         (void)flags;
 308         meshlink_handle_t *mesh = userdata;
 309
 310         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 311         switch(event) {
 312         case CATTA_BROWSER_FAILURE:
 313                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 314                         abort();
 315                 }
 316
 317                 catta_simple_poll_quit(mesh->catta_poll);
 318                 pthread_mutex_unlock(&mesh->mutex);
 319                 break;
 320
 321         case CATTA_BROWSER_NEW:
 322                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 323                         abort();
 324                 }
 325
 326                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 327                 handle_network_change(mesh, ++mesh->catta_interfaces);
 328                 pthread_mutex_unlock(&mesh->mutex);
 329                 break;
 330
 331         case CATTA_BROWSER_REMOVE:
 332                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 333                         abort();
 334                 }
 335
 336                 handle_network_change(mesh, --mesh->catta_interfaces);
 337                 pthread_mutex_unlock(&mesh->mutex);
 338                 break;
 339
 340         case CATTA_BROWSER_ALL_FOR_NOW:
 341         case CATTA_BROWSER_CACHE_EXHAUSTED:
 342                 break;
 343         }
 344 }
 345
 346 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 347         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 348
 349         switch(level) {
 350         case CATTA_LOG_ERROR:
 351                 mlevel = MESHLINK_ERROR;
 352                 break;
 353
 354         case CATTA_LOG_WARN:
 355                 mlevel = MESHLINK_WARNING;
 356                 break;
 357
 358         case CATTA_LOG_NOTICE:
 359         case CATTA_LOG_INFO:
 360                 mlevel = MESHLINK_INFO;
 361                 break;
 362
 363         case CATTA_LOG_DEBUG:
 364         default:
 365                 mlevel = MESHLINK_DEBUG;
 366                 break;
 367         }
 368
 369         logger(NULL, mlevel, "%s\n", txt);
 370 }
 371
 372 static void *discovery_loop(void *userdata) {
 373         bool status = false;
 374         meshlink_handle_t *mesh = userdata;
 375         assert(mesh);
 376
 377         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 378                 abort();
 379         }
 380
 381         // handle catta logs
 382         catta_set_log_function(discovery_log_cb);
 383
 384         // create service type string
 385         char appname[strlen(mesh->appname) + 2];
 386         strcpy(appname, mesh->appname);
 387
 388         for(char *p = appname; *p; p++) {
 389                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 390                         *p = '_';
 391                 }
 392         }
 393
 394         if(!appname[1]) {
 395                 appname[1] = '_';
 396                 appname[2] = '\0';
 397         }
 398
 399         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 400         mesh->catta_servicetype = malloc(servicetype_strlen);
 401
 402         if(mesh->catta_servicetype == NULL) {
 403                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 404                 goto fail;
 405         }
 406
 407         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 408
 409         // Allocate discovery loop object
 410         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 411                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 412                 goto fail;
 413         }
 414
 415         // generate some unique host name (we actually do not care about it)
 416         char hostname[17];
 417         generate_rand_string(mesh, hostname, sizeof(hostname));
 418
 419         // Let's set the host name for this server.
 420         CattaServerConfig config;
 421         catta_server_config_init(&config);
 422         config.host_name = catta_strdup(hostname);
 423         config.publish_workstation = 0;
 424         config.disallow_other_stacks = 0;
 425         config.publish_hinfo = 0;
 426         config.publish_addresses = 1;
 427         config.publish_no_reverse = 1;
 428         config.allow_point_to_point = 1;
 429
 430         /* Allocate a new server */
 431         int error;
 432         const CattaPoll *poller = catta_simple_poll_get(mesh->catta_poll);
 433
 434         if(!poller) {
 435                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 436                 goto fail;
 437         }
 438
 439         mesh->catta_server = catta_server_new(poller, &config, discovery_server_callback, mesh, &error);
 440
 441         /* Free the configuration data */
 442         catta_server_config_free(&config);
 443
 444         /* Check whether creating the server object succeeded */
 445         if(!mesh->catta_server) {
 446                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 447                 goto fail;
 448         }
 449
 450         // Create the service browser
 451         if(!(mesh->catta_browser = catta_s_service_browser_new(mesh->catta_server, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, mesh->catta_servicetype, NULL, 0, discovery_browse_callback, mesh))) {
 452                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 453                 goto fail;
 454         }
 455
 456         status = true;
 457
 458 fail:
 459
 460         pthread_cond_broadcast(&mesh->discovery_cond);
 461         pthread_mutex_unlock(&mesh->discovery_mutex);
 462
 463         if(status) {
 464                 catta_simple_poll_loop(mesh->catta_poll);
 465         }
 466
 467         if(mesh->catta_browser) {
 468                 catta_s_service_browser_free(mesh->catta_browser);
 469                 mesh->catta_browser = NULL;
 470         }
 471
 472         if(mesh->catta_group) {
 473                 catta_s_entry_group_reset(mesh->catta_group);
 474                 catta_s_entry_group_free(mesh->catta_group);
 475                 mesh->catta_group = NULL;
 476         }
 477
 478         if(mesh->catta_server) {
 479                 catta_server_free(mesh->catta_server);
 480                 mesh->catta_server = NULL;
 481         }
 482
 483         if(mesh->catta_poll) {
 484                 catta_simple_poll_free(mesh->catta_poll);
 485                 mesh->catta_poll = NULL;
 486         }
 487
 488         if(mesh->catta_servicetype) {
 489                 free(mesh->catta_servicetype);
 490                 mesh->catta_servicetype = NULL;
 491         }
 492
 493         return NULL;
 494 }
 495
 496 #if defined(__linux)
 497 static void netlink_getlink(int fd) {
 498         static const struct {
 499                 struct nlmsghdr nlm;
 500                 struct ifinfomsg ifi;
 501         } msg = {
 502                 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
 503                 .nlm.nlmsg_type = RTM_GETLINK,
 504                 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 505                 .nlm.nlmsg_seq = 1,
 506                 .ifi.ifi_family = AF_UNSPEC,
 507         };
 508         send(fd, &msg, msg.nlm.nlmsg_len, 0);
 509 }
 510
 511 static void netlink_getaddr(int fd) {
 512         static const struct {
 513                 struct nlmsghdr nlm;
 514                 struct ifaddrmsg ifa;
 515         } msg = {
 516                 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
 517                 .nlm.nlmsg_type = RTM_GETADDR,
 518                 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 519                 .nlm.nlmsg_seq = 2,
 520                 .ifa.ifa_family = AF_UNSPEC,
 521         };
 522         send(fd, &msg, msg.nlm.nlmsg_len, 0);
 523 }
 524
 525 static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
 526         const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
 527
 528         if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
 529                 logger(mesh, MESHLINK_INFO, "iface %d active\n", ifi->ifi_index);
 530         } else {
 531                 logger(mesh, MESHLINK_INFO, "iface %d inactive\n", ifi->ifi_index);
 532         }
 533 }
 534
 535 static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
 536         const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
 537         const uint8_t *ptr = (const uint8_t *)(ifa + 1);
 538         size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
 539
 540         while(len >= sizeof(struct rtattr)) {
 541                 const struct rtattr *rta = (const struct rtattr *)ptr;
 542
 543                 if(rta->rta_len <= 0 || rta->rta_len > len) {
 544                         break;
 545                 }
 546
 547                 if(rta->rta_type == IFA_ADDRESS) {
 548                         char dest[40] = "?";
 549
 550                         if(rta->rta_len == 8) {
 551                                 inet_ntop(AF_INET, ptr + 4, dest, sizeof dest);
 552                         } else if(rta->rta_len == 20) {
 553                                 inet_ntop(AF_INET6, ptr + 4, dest, sizeof dest);
 554                         }
 555
 556                         logger(mesh, MESHLINK_INFO, "iface %d address %s %s\n", ifa->ifa_index, dest, nlm->nlmsg_type == RTM_NEWADDR ? "new" : "del");
 557                 }
 558
 559                 unsigned short rta_len = (rta->rta_len + 3) & ~3;
 560                 ptr += rta_len;
 561                 len -= rta_len;
 562         }
 563 }
 564
 565 static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
 566         const uint8_t *ptr = data;
 567
 568         while(len >= sizeof(struct nlmsghdr)) {
 569                 const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
 570
 571                 if(nlm->nlmsg_len > len) {
 572                         break;
 573                 }
 574
 575                 switch(nlm->nlmsg_type) {
 576                 case RTM_NEWLINK:
 577                 case RTM_DELLINK:
 578                         netlink_parse_link(mesh, nlm);
 579                         break;
 580
 581                 case RTM_NEWADDR:
 582                 case RTM_DELADDR:
 583                         netlink_parse_addr(mesh, nlm);
 584                 }
 585
 586                 ptr += nlm->nlmsg_len;
 587                 len -= nlm->nlmsg_len;
 588         }
 589 }
 590
 591 static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
 592         (void)flags;
 593         static time_t prev_update;
 594         meshlink_handle_t *mesh = data;
 595
 596         struct {
 597                 struct nlmsghdr nlm;
 598                 char data[16384];
 599         } msg;
 600
 601         while(true) {
 602                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 603
 604                 if(result <= 0) {
 605                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 606                                 break;
 607                         }
 608
 609                         logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
 610                         io_set(loop, &mesh->pfroute_io, 0);
 611                 }
 612
 613                 if((size_t)result < sizeof(msg.nlm)) {
 614                         logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
 615                         break;
 616                 }
 617
 618                 if(msg.nlm.nlmsg_type == NLMSG_DONE) {
 619                         if(msg.nlm.nlmsg_seq == 1) {
 620                                 // We just got the result of GETLINK, now send GETADDR.
 621                                 netlink_getaddr(mesh->pfroute_io.fd);
 622                         }
 623                 } else {
 624                         netlink_parse(mesh, &msg, result);
 625
 626                         if(loop->now.tv_sec > prev_update + 5) {
 627                                 prev_update = loop->now.tv_sec;
 628                                 handle_network_change(mesh, 1);
 629                         }
 630                 }
 631         }
 632 }
 633 #elif defined(RTM_NEWADDR)
 634 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 635         (void)flags;
 636         static time_t prev_update;
 637         meshlink_handle_t *mesh = data;
 638
 639         struct {
 640                 struct rt_msghdr rtm;
 641                 char data[2048];
 642         } msg;
 643
 644         while(true) {
 645                 msg.rtm.rtm_version = 0;
 646                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 647
 648                 if(result <= 0) {
 649                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 650                                 break;
 651                         }
 652
 653                         logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
 654                         io_set(loop, &mesh->pfroute_io, 0);
 655                 }
 656
 657                 if(msg.rtm.rtm_version != RTM_VERSION) {
 658                         logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
 659                         break;
 660                 }
 661
 662                 switch(msg.rtm.rtm_type) {
 663                 case RTM_IFINFO:
 664                 case RTM_NEWADDR:
 665                 case RTM_DELADDR:
 666                         if(loop->now.tv_sec > prev_update + 5) {
 667                                 prev_update = loop->now.tv_sec;
 668                                 handle_network_change(mesh, 1);
 669                         }
 670
 671                         break;
 672
 673                 default:
 674                         break;
 675                 }
 676         }
 677 }
 678 #endif
 679
 680 bool discovery_start(meshlink_handle_t *mesh) {
 681         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 682
 683         assert(mesh);
 684         assert(!mesh->catta_poll);
 685         assert(!mesh->catta_server);
 686         assert(!mesh->catta_browser);
 687         assert(!mesh->discovery_threadstarted);
 688         assert(!mesh->catta_servicetype);
 689
 690         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 691                 abort();
 692         }
 693
 694         // Start the discovery thread
 695         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 696                 pthread_mutex_unlock(&mesh->discovery_mutex);
 697                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 698                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 699                 return false;
 700         }
 701
 702         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 703         pthread_mutex_unlock(&mesh->discovery_mutex);
 704
 705         mesh->discovery_threadstarted = true;
 706
 707 #if defined(__linux)
 708         int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
 709
 710         if(sock != -1) {
 711                 struct sockaddr_nl sa;
 712                 memset(&sa, 0, sizeof(sa));
 713                 sa.nl_family = AF_NETLINK;
 714                 sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
 715
 716                 if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
 717                         io_add(&mesh->loop, &mesh->pfroute_io, netlink_io_handler, mesh, sock, IO_READ);
 718                         netlink_getlink(sock);
 719                 } else {
 720                         logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
 721                 }
 722         } else {
 723                 logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
 724         }
 725
 726 #elif defined(RTM_NEWADDR)
 727         int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
 728
 729         if(sock != -1) {
 730                 io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
 731         } else {
 732                 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
 733         }
 734
 735 #endif
 736
 737         return true;
 738 }
 739
 740 void discovery_stop(meshlink_handle_t *mesh) {
 741         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 742
 743         assert(mesh);
 744
 745         if(mesh->pfroute_io.cb) {
 746                 close(mesh->pfroute_io.fd);
 747                 io_del(&mesh->loop, &mesh->pfroute_io);
 748         }
 749
 750         // Shut down
 751         if(mesh->catta_poll) {
 752                 catta_simple_poll_quit(mesh->catta_poll);
 753         }
 754
 755         // Wait for the discovery thread to finish
 756         if(mesh->discovery_threadstarted == true) {
 757                 if(pthread_join(mesh->discovery_thread, NULL) != 0) {
 758                         abort();
 759                 }
 760
 761                 mesh->discovery_threadstarted = false;
 762         }
 763
 764         mesh->catta_interfaces = 0;
 765 }