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 "netutl.h"
  28 #include "node.h"
  29 #include "connection.h"
  30 #include "xalloc.h"
  31
  32 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  33 #define MESHLINK_MDNS_NAME_KEY "name"
  34 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  35
  36 static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
  37         assert(size);
  38
  39         for(size_t i = 0; i < (size - 1); ++i) {
  40                 buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
  41         }
  42
  43         buffer[size - 1] = '\0';
  44 }
  45
  46 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  47         (void)server;
  48         (void)group;
  49         meshlink_handle_t *mesh = userdata;
  50
  51         assert(mesh);
  52         assert(mesh->catta_server);
  53         assert(mesh->catta_poll);
  54
  55         /* Called whenever the entry group state changes */
  56         switch(state) {
  57         case CATTA_ENTRY_GROUP_ESTABLISHED:
  58                 /* The entry group has been established successfully */
  59                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  60                 break;
  61
  62         case CATTA_ENTRY_GROUP_COLLISION:
  63                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  64                 // @TODO can we just set a new name and retry?
  65                 break;
  66
  67         case CATTA_ENTRY_GROUP_FAILURE :
  68                 /* Some kind of failure happened while we were registering our services */
  69                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  70                 catta_simple_poll_quit(mesh->catta_poll);
  71                 break;
  72
  73         case CATTA_ENTRY_GROUP_UNCOMMITED:
  74         case CATTA_ENTRY_GROUP_REGISTERING:
  75                 break;
  76         }
  77 }
  78
  79
  80 static void discovery_create_services(meshlink_handle_t *mesh) {
  81         char *fingerprint = NULL;
  82         char *txt_name = NULL;
  83         char *txt_fingerprint = NULL;
  84
  85         assert(mesh);
  86         assert(mesh->name);
  87         assert(mesh->myport);
  88         assert(mesh->catta_server);
  89         assert(mesh->catta_poll);
  90         assert(mesh->catta_servicetype);
  91         assert(mesh->self);
  92
  93         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  94
  95         /* If this is the first time we're called, let's create a new entry group */
  96         if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  97                 logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  98                 goto fail;
  99         }
 100
 101         /* Create txt records */
 102         fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
 103         xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
 104         xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
 105
 106         /* Add the service */
 107         int ret = 0;
 108
 109         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) {
 110                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 111                 goto fail;
 112         }
 113
 114         /* Tell the server to register the service */
 115         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 116                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 117                 goto fail;
 118         }
 119
 120         goto done;
 121
 122 fail:
 123         catta_simple_poll_quit(mesh->catta_poll);
 124
 125 done:
 126         free(fingerprint);
 127         free(txt_name);
 128         free(txt_fingerprint);
 129 }
 130
 131 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 132         (void)server;
 133         meshlink_handle_t *mesh = userdata;
 134
 135         assert(mesh);
 136
 137         switch(state) {
 138         case CATTA_SERVER_RUNNING:
 139
 140                 /* The serve has startup successfully and registered its host
 141                  * name on the network, so it's time to create our services */
 142                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 143                         abort();
 144                 }
 145
 146                 if(!mesh->catta_group) {
 147                         discovery_create_services(mesh);
 148                 }
 149
 150                 pthread_mutex_unlock(&mesh->mutex);
 151
 152                 break;
 153
 154         case CATTA_SERVER_COLLISION: {
 155                 /* A host name collision happened. Let's pick a new name for the server */
 156                 char hostname[17];
 157                 generate_rand_string(mesh, hostname, sizeof(hostname));
 158
 159                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 160                         abort();
 161                 }
 162
 163                 assert(mesh->catta_server);
 164                 assert(mesh->catta_poll);
 165
 166                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 167
 168                 if(result < 0) {
 169                         catta_simple_poll_quit(mesh->catta_poll);
 170                 }
 171
 172                 pthread_mutex_unlock(&mesh->mutex);
 173         }
 174         break;
 175
 176         case CATTA_SERVER_REGISTERING:
 177                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 178                         abort();
 179                 }
 180
 181                 /* Let's drop our registered services. When the server is back
 182                  * in CATTA_SERVER_RUNNING state we will register them
 183                  * again with the new host name. */
 184                 if(mesh->catta_group) {
 185                         catta_s_entry_group_reset(mesh->catta_group);
 186                         mesh->catta_group = NULL;
 187                 }
 188
 189                 pthread_mutex_unlock(&mesh->mutex);
 190
 191                 break;
 192
 193         case CATTA_SERVER_FAILURE:
 194                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 195                         abort();
 196                 }
 197
 198                 assert(mesh->catta_server);
 199                 assert(mesh->catta_poll);
 200
 201                 /* Terminate on failure */
 202                 catta_simple_poll_quit(mesh->catta_poll);
 203
 204                 pthread_mutex_unlock(&mesh->mutex);
 205                 break;
 206
 207         case CATTA_SERVER_INVALID:
 208                 break;
 209         }
 210 }
 211
 212 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) {
 213         (void)interface_;
 214         (void)protocol;
 215         (void)flags;
 216         (void)name;
 217         (void)type;
 218         (void)domain;
 219         (void)host_name;
 220
 221         meshlink_handle_t *mesh = userdata;
 222
 223         assert(mesh);
 224
 225         if(event != CATTA_RESOLVER_FOUND) {
 226                 catta_s_service_resolver_free(resolver);
 227                 return;
 228         }
 229
 230         // retrieve fingerprint
 231         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 232         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 233
 234         if(node_name_li && node_fp_li) {
 235                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 236                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 237
 238                 if(node_name[0] == '=' && node_fp[0] == '=') {
 239                         if(pthread_mutex_lock(&mesh->mutex) != 0) {
 240                                 abort();
 241                         }
 242
 243                         node_name += 1;
 244
 245                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 246
 247                         if(node) {
 248                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 249
 250                                 sockaddr_t naddress;
 251                                 memset(&naddress, 0, sizeof(naddress));
 252
 253                                 switch(address->proto) {
 254                                 case CATTA_PROTO_INET: {
 255                                         naddress.in.sin_family = AF_INET;
 256                                         naddress.in.sin_port = htons(port);
 257                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 258                                 }
 259                                 break;
 260
 261                                 case CATTA_PROTO_INET6: {
 262                                         naddress.in6.sin6_family = AF_INET6;
 263                                         naddress.in6.sin6_port = htons(port);
 264                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 265                                 }
 266                                 break;
 267
 268                                 default:
 269                                         naddress.unknown.family = AF_UNKNOWN;
 270                                         break;
 271                                 }
 272
 273                                 if(naddress.unknown.family != AF_UNKNOWN) {
 274                                         node_t *n = (node_t *)node;
 275                                         connection_t *c = n->connection;
 276
 277                                         n->catta_address = naddress;
 278                                         node_add_recent_address(mesh, n, &naddress);
 279
 280                                         if(c && c->outgoing && !c->status.active) {
 281                                                 c->outgoing->timeout = 0;
 282
 283                                                 if(c->outgoing->ev.cb) {
 284                                                         timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
 285                                                                 0, 0
 286                                                         });
 287                                                 }
 288
 289                                                 c->last_ping_time = -3600;
 290                                         }
 291
 292                                 } else {
 293                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 294                                 }
 295                         } else {
 296                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 297                         }
 298
 299                         pthread_mutex_unlock(&mesh->mutex);
 300                 }
 301         }
 302
 303         catta_s_service_resolver_free(resolver);
 304 }
 305
 306 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) {
 307         (void)browser;
 308         (void)flags;
 309         meshlink_handle_t *mesh = userdata;
 310
 311         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 312         switch(event) {
 313         case CATTA_BROWSER_FAILURE:
 314                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 315                         abort();
 316                 }
 317
 318                 catta_simple_poll_quit(mesh->catta_poll);
 319                 pthread_mutex_unlock(&mesh->mutex);
 320                 break;
 321
 322         case CATTA_BROWSER_NEW:
 323                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 324                         abort();
 325                 }
 326
 327                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 328                 handle_network_change(mesh, ++mesh->catta_interfaces);
 329                 pthread_mutex_unlock(&mesh->mutex);
 330                 break;
 331
 332         case CATTA_BROWSER_REMOVE:
 333                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 334                         abort();
 335                 }
 336
 337                 handle_network_change(mesh, --mesh->catta_interfaces);
 338                 pthread_mutex_unlock(&mesh->mutex);
 339                 break;
 340
 341         case CATTA_BROWSER_ALL_FOR_NOW:
 342         case CATTA_BROWSER_CACHE_EXHAUSTED:
 343                 break;
 344         }
 345 }
 346
 347 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 348         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 349
 350         switch(level) {
 351         case CATTA_LOG_ERROR:
 352                 mlevel = MESHLINK_ERROR;
 353                 break;
 354
 355         case CATTA_LOG_WARN:
 356                 mlevel = MESHLINK_WARNING;
 357                 break;
 358
 359         case CATTA_LOG_NOTICE:
 360         case CATTA_LOG_INFO:
 361                 mlevel = MESHLINK_INFO;
 362                 break;
 363
 364         case CATTA_LOG_DEBUG:
 365         default:
 366                 mlevel = MESHLINK_DEBUG;
 367                 break;
 368         }
 369
 370         logger(NULL, mlevel, "%s\n", txt);
 371 }
 372
 373 static void *discovery_loop(void *userdata) {
 374         bool status = false;
 375         meshlink_handle_t *mesh = userdata;
 376         assert(mesh);
 377
 378         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 379                 abort();
 380         }
 381
 382         // handle catta logs
 383         catta_set_log_function(discovery_log_cb);
 384
 385         // create service type string
 386         char appname[strlen(mesh->appname) + 2];
 387         strcpy(appname, mesh->appname);
 388
 389         for(char *p = appname; *p; p++) {
 390                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 391                         *p = '_';
 392                 }
 393         }
 394
 395         if(!appname[1]) {
 396                 appname[1] = '_';
 397                 appname[2] = '\0';
 398         }
 399
 400         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 401         mesh->catta_servicetype = malloc(servicetype_strlen);
 402
 403         if(mesh->catta_servicetype == NULL) {
 404                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 405                 goto fail;
 406         }
 407
 408         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 409
 410         // Allocate discovery loop object
 411         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 412                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 413                 goto fail;
 414         }
 415
 416         // generate some unique host name (we actually do not care about it)
 417         char hostname[17];
 418         generate_rand_string(mesh, hostname, sizeof(hostname));
 419
 420         // Let's set the host name for this server.
 421         CattaServerConfig config;
 422         catta_server_config_init(&config);
 423         config.host_name = catta_strdup(hostname);
 424         config.publish_workstation = 0;
 425         config.disallow_other_stacks = 0;
 426         config.publish_hinfo = 0;
 427         config.publish_addresses = 1;
 428         config.publish_no_reverse = 1;
 429         config.allow_point_to_point = 1;
 430
 431         /* Allocate a new server */
 432         int error;
 433         const CattaPoll *poller = catta_simple_poll_get(mesh->catta_poll);
 434
 435         if(!poller) {
 436                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 437                 goto fail;
 438         }
 439
 440         mesh->catta_server = catta_server_new(poller, &config, discovery_server_callback, mesh, &error);
 441
 442         /* Free the configuration data */
 443         catta_server_config_free(&config);
 444
 445         /* Check whether creating the server object succeeded */
 446         if(!mesh->catta_server) {
 447                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 448                 goto fail;
 449         }
 450
 451         // Create the service browser
 452         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))) {
 453                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 454                 goto fail;
 455         }
 456
 457         status = true;
 458
 459 fail:
 460
 461         pthread_cond_broadcast(&mesh->discovery_cond);
 462         pthread_mutex_unlock(&mesh->discovery_mutex);
 463
 464         if(status) {
 465                 catta_simple_poll_loop(mesh->catta_poll);
 466         }
 467
 468         if(mesh->catta_browser) {
 469                 catta_s_service_browser_free(mesh->catta_browser);
 470                 mesh->catta_browser = NULL;
 471         }
 472
 473         if(mesh->catta_group) {
 474                 catta_s_entry_group_reset(mesh->catta_group);
 475                 catta_s_entry_group_free(mesh->catta_group);
 476                 mesh->catta_group = NULL;
 477         }
 478
 479         if(mesh->catta_server) {
 480                 catta_server_free(mesh->catta_server);
 481                 mesh->catta_server = NULL;
 482         }
 483
 484         if(mesh->catta_poll) {
 485                 catta_simple_poll_free(mesh->catta_poll);
 486                 mesh->catta_poll = NULL;
 487         }
 488
 489         if(mesh->catta_servicetype) {
 490                 free(mesh->catta_servicetype);
 491                 mesh->catta_servicetype = NULL;
 492         }
 493
 494         return NULL;
 495 }
 496
 497 typedef struct discovery_address {
 498         int index;
 499         bool up;
 500         sockaddr_t address;
 501 } discovery_address_t;
 502
 503 static int iface_compare(const void *va, const void *vb) {
 504         const int *a = va;
 505         const int *b = vb;
 506         return *a - *b;
 507 }
 508
 509 static int address_compare(const void *va, const void *vb) {
 510         const discovery_address_t *a = va;
 511         const discovery_address_t *b = vb;
 512
 513         if(a->index != b->index) {
 514                 return a->index - b->index;
 515         }
 516
 517         return sockaddrcmp_noport(&a->address, &b->address);
 518 }
 519
 520 static void send_mdns_packet(meshlink_handle_t *mesh, const discovery_address_t *addr) {
 521         char *host = NULL, *port = NULL;
 522         sockaddr2str(&addr->address, &host, &port);
 523         fprintf(stderr, "Sending on iface %d %s port %s\n", addr->index, host, port);
 524         free(host);
 525         free(port);
 526 }
 527
 528 static void iface_up(meshlink_handle_t *mesh, int index) {
 529         int *p = bsearch(&index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
 530
 531         if(p) {
 532                 return;
 533         }
 534
 535         fprintf(stderr, "iface %d up\n", index);
 536         mesh->discovery_ifaces = xrealloc(mesh->discovery_ifaces, ++mesh->discovery_iface_count * sizeof(*p));
 537         mesh->discovery_ifaces[mesh->discovery_iface_count - 1] = index;
 538         qsort(mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
 539
 540         for(int i = 0; i < mesh->discovery_iface_count; i++) {
 541                 fprintf(stderr, "%d", mesh->discovery_ifaces[i]);
 542         }
 543
 544         // Send an announcement for all addresses associated with this interface
 545         for(int i = 0; i < mesh->discovery_address_count; i++) {
 546                 if(mesh->discovery_addresses[i].index == index) {
 547                         send_mdns_packet(mesh, &mesh->discovery_addresses[i]);
 548                 }
 549         }
 550 }
 551
 552 static void iface_down(meshlink_handle_t *const mesh, int index) {
 553         int *p = bsearch(&index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(int), iface_compare);
 554
 555         if(!p) {
 556                 return;
 557         }
 558
 559         fprintf(stderr, "iface %d down\n", index);
 560         memmove(p, p + 1, --mesh->discovery_iface_count * sizeof(*p));
 561 }
 562
 563 static void addr_add(meshlink_handle_t *mesh, const discovery_address_t *addr) {
 564         discovery_address_t *p = bsearch(addr, mesh->discovery_addresses, mesh->discovery_address_count, sizeof(int), address_compare);
 565
 566         if(p) {
 567                 return;
 568         }
 569
 570         bool up = bsearch(&addr->index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
 571         char *host = NULL, *port = NULL;
 572         sockaddr2str(&addr->address, &host, &port);
 573         fprintf(stderr, "address %d %s port %s up %d\n", addr->index, host, port, up);
 574         free(host);
 575         free(port);
 576
 577         mesh->discovery_addresses = xrealloc(mesh->discovery_addresses, ++mesh->discovery_address_count * sizeof(*p));
 578         mesh->discovery_addresses[mesh->discovery_address_count - 1] = *addr;
 579         qsort(mesh->discovery_addresses, mesh->discovery_address_count, sizeof(*p), address_compare);
 580
 581         mesh->discovery_addresses[mesh->discovery_address_count - 1].up = up;
 582
 583         if(up) {
 584                 send_mdns_packet(mesh, &mesh->discovery_addresses[mesh->discovery_address_count - 1]);
 585         }
 586 }
 587
 588 static void addr_del(meshlink_handle_t *mesh, const discovery_address_t *addr) {
 589         discovery_address_t *p = bsearch(addr, mesh->discovery_addresses, mesh->discovery_address_count, sizeof(*p), address_compare);
 590
 591         if(!p) {
 592                 return;
 593         }
 594
 595         char *host = NULL, *port = NULL;
 596         sockaddr2str(&addr->address, &host, &port);
 597         fprintf(stderr, "address %d %s port %s down\n", addr->index, host, port);
 598         free(host);
 599         free(port);
 600
 601         memmove(p, p + 1, --mesh->discovery_address_count * sizeof(*p));
 602 }
 603
 604 #if defined(__linux)
 605 static void netlink_getlink(int fd) {
 606         static const struct {
 607                 struct nlmsghdr nlm;
 608                 struct ifinfomsg ifi;
 609         } msg = {
 610                 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
 611                 .nlm.nlmsg_type = RTM_GETLINK,
 612                 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 613                 .nlm.nlmsg_seq = 1,
 614                 .ifi.ifi_family = AF_UNSPEC,
 615         };
 616         send(fd, &msg, msg.nlm.nlmsg_len, 0);
 617 }
 618
 619 static void netlink_getaddr(int fd) {
 620         static const struct {
 621                 struct nlmsghdr nlm;
 622                 struct ifaddrmsg ifa;
 623         } msg = {
 624                 .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
 625                 .nlm.nlmsg_type = RTM_GETADDR,
 626                 .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 627                 .nlm.nlmsg_seq = 2,
 628                 .ifa.ifa_family = AF_UNSPEC,
 629         };
 630         send(fd, &msg, msg.nlm.nlmsg_len, 0);
 631 }
 632
 633
 634 static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
 635         const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
 636
 637         if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
 638                 iface_up(mesh, ifi->ifi_index);
 639         } else {
 640                 iface_down(mesh, ifi->ifi_index);
 641         }
 642 }
 643
 644 static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
 645         const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
 646         const uint8_t *ptr = (const uint8_t *)(ifa + 1);
 647         size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
 648
 649         while(len >= sizeof(struct rtattr)) {
 650                 const struct rtattr *rta = (const struct rtattr *)ptr;
 651
 652                 if(rta->rta_len <= 0 || rta->rta_len > len) {
 653                         break;
 654                 }
 655
 656                 if(rta->rta_type == IFA_ADDRESS) {
 657                         discovery_address_t addr  = {
 658                                 .index = ifa->ifa_index,
 659                         };
 660
 661                         if(rta->rta_len == 8) {
 662                                 addr.address.sa.sa_family = AF_INET;
 663                                 memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
 664                                 addr.address.in.sin_port = 5353;
 665                         } else if(rta->rta_len == 20) {
 666                                 addr.address.sa.sa_family = AF_INET6;
 667                                 memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
 668                                 addr.address.in6.sin6_port = 5353;
 669                                 addr.address.in6.sin6_scope_id = ifa->ifa_index;
 670                         } else {
 671                                 addr.address.sa.sa_family = AF_UNKNOWN;
 672                         }
 673
 674                         if(addr.address.sa.sa_family != AF_UNKNOWN) {
 675                                 if(nlm->nlmsg_type == RTM_NEWADDR) {
 676                                         addr_add(mesh, &addr);
 677                                 } else {
 678                                         addr_del(mesh, &addr);
 679                                 }
 680                         }
 681                 }
 682
 683                 unsigned short rta_len = (rta->rta_len + 3) & ~3;
 684                 ptr += rta_len;
 685                 len -= rta_len;
 686         }
 687 }
 688
 689 static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
 690         const uint8_t *ptr = data;
 691
 692         while(len >= sizeof(struct nlmsghdr)) {
 693                 const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
 694
 695                 if(nlm->nlmsg_len > len) {
 696                         break;
 697                 }
 698
 699                 switch(nlm->nlmsg_type) {
 700                 case RTM_NEWLINK:
 701                 case RTM_DELLINK:
 702                         netlink_parse_link(mesh, nlm);
 703                         break;
 704
 705                 case RTM_NEWADDR:
 706                 case RTM_DELADDR:
 707                         netlink_parse_addr(mesh, nlm);
 708                 }
 709
 710                 ptr += nlm->nlmsg_len;
 711                 len -= nlm->nlmsg_len;
 712         }
 713 }
 714
 715 static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
 716         (void)flags;
 717         static time_t prev_update;
 718         meshlink_handle_t *mesh = data;
 719
 720         struct {
 721                 struct nlmsghdr nlm;
 722                 char data[16384];
 723         } msg;
 724
 725         while(true) {
 726                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 727
 728                 if(result <= 0) {
 729                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 730                                 break;
 731                         }
 732
 733                         logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
 734                         io_set(loop, &mesh->pfroute_io, 0);
 735                 }
 736
 737                 if((size_t)result < sizeof(msg.nlm)) {
 738                         logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
 739                         break;
 740                 }
 741
 742                 if(msg.nlm.nlmsg_type == NLMSG_DONE) {
 743                         if(msg.nlm.nlmsg_seq == 1) {
 744                                 // We just got the result of GETLINK, now send GETADDR.
 745                                 netlink_getaddr(mesh->pfroute_io.fd);
 746                         }
 747                 } else {
 748                         netlink_parse(mesh, &msg, result);
 749
 750                         if(loop->now.tv_sec > prev_update + 5) {
 751                                 prev_update = loop->now.tv_sec;
 752                                 handle_network_change(mesh, 1);
 753                         }
 754                 }
 755         }
 756 }
 757 #elif defined(RTM_NEWADDR)
 758 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 759         (void)flags;
 760         static time_t prev_update;
 761         meshlink_handle_t *mesh = data;
 762
 763         struct {
 764                 struct rt_msghdr rtm;
 765                 char data[2048];
 766         } msg;
 767
 768         while(true) {
 769                 msg.rtm.rtm_version = 0;
 770                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 771
 772                 if(result <= 0) {
 773                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 774                                 break;
 775                         }
 776
 777                         logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
 778                         io_set(loop, &mesh->pfroute_io, 0);
 779                 }
 780
 781                 if(msg.rtm.rtm_version != RTM_VERSION) {
 782                         logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
 783                         break;
 784                 }
 785
 786                 switch(msg.rtm.rtm_type) {
 787                 case RTM_IFINFO:
 788                 case RTM_NEWADDR:
 789                 case RTM_DELADDR:
 790                         if(loop->now.tv_sec > prev_update + 5) {
 791                                 prev_update = loop->now.tv_sec;
 792                                 handle_network_change(mesh, 1);
 793                         }
 794
 795                         break;
 796
 797                 default:
 798                         break;
 799                 }
 800         }
 801 }
 802 #endif
 803
 804 bool discovery_start(meshlink_handle_t *mesh) {
 805         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 806
 807         assert(mesh);
 808         assert(!mesh->catta_poll);
 809         assert(!mesh->catta_server);
 810         assert(!mesh->catta_browser);
 811         assert(!mesh->discovery_threadstarted);
 812         assert(!mesh->catta_servicetype);
 813
 814         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 815                 abort();
 816         }
 817
 818         // Start the discovery thread
 819         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 820                 pthread_mutex_unlock(&mesh->discovery_mutex);
 821                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 822                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 823                 return false;
 824         }
 825
 826         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 827         pthread_mutex_unlock(&mesh->discovery_mutex);
 828
 829         mesh->discovery_threadstarted = true;
 830
 831 #if defined(__linux)
 832         int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
 833
 834         if(sock != -1) {
 835                 struct sockaddr_nl sa;
 836                 memset(&sa, 0, sizeof(sa));
 837                 sa.nl_family = AF_NETLINK;
 838                 sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
 839
 840                 if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
 841                         io_add(&mesh->loop, &mesh->pfroute_io, netlink_io_handler, mesh, sock, IO_READ);
 842                         netlink_getlink(sock);
 843                 } else {
 844                         logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
 845                 }
 846         } else {
 847                 logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
 848         }
 849
 850 #elif defined(RTM_NEWADDR)
 851         int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
 852
 853         if(sock != -1) {
 854                 io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
 855         } else {
 856                 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
 857         }
 858
 859 #endif
 860
 861         return true;
 862 }
 863
 864 void discovery_stop(meshlink_handle_t *mesh) {
 865         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 866
 867         assert(mesh);
 868
 869         free(mesh->discovery_ifaces);
 870         free(mesh->discovery_addresses);
 871         mesh->discovery_iface_count = 0;
 872         mesh->discovery_address_count = 0;
 873
 874         if(mesh->pfroute_io.cb) {
 875                 close(mesh->pfroute_io.fd);
 876                 io_del(&mesh->loop, &mesh->pfroute_io);
 877         }
 878
 879         // Shut down
 880         if(mesh->catta_poll) {
 881                 catta_simple_poll_quit(mesh->catta_poll);
 882         }
 883
 884         // Wait for the discovery thread to finish
 885         if(mesh->discovery_threadstarted == true) {
 886                 if(pthread_join(mesh->discovery_thread, NULL) != 0) {
 887                         abort();
 888                 }
 889
 890                 mesh->discovery_threadstarted = false;
 891         }
 892
 893         mesh->catta_interfaces = 0;
 894 }