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 #endif
  15
  16 #include "meshlink_internal.h"
  17 #include "event.h"
  18 #include "discovery.h"
  19 #include "sockaddr.h"
  20 #include "logger.h"
  21 #include "node.h"
  22 #include "connection.h"
  23 #include "xalloc.h"
  24
  25 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  26 #define MESHLINK_MDNS_NAME_KEY "name"
  27 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  28
  29 static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
  30         assert(size);
  31
  32         for(size_t i = 0; i < (size - 1); ++i) {
  33                 buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
  34         }
  35
  36         buffer[size - 1] = '\0';
  37 }
  38
  39 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  40         (void)server;
  41         (void)group;
  42         meshlink_handle_t *mesh = userdata;
  43
  44         assert(mesh);
  45         assert(mesh->catta_server);
  46         assert(mesh->catta_poll);
  47
  48         /* Called whenever the entry group state changes */
  49         switch(state) {
  50         case CATTA_ENTRY_GROUP_ESTABLISHED:
  51                 /* The entry group has been established successfully */
  52                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  53                 break;
  54
  55         case CATTA_ENTRY_GROUP_COLLISION:
  56                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  57                 // @TODO can we just set a new name and retry?
  58                 break;
  59
  60         case CATTA_ENTRY_GROUP_FAILURE :
  61                 /* Some kind of failure happened while we were registering our services */
  62                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  63                 catta_simple_poll_quit(mesh->catta_poll);
  64                 break;
  65
  66         case CATTA_ENTRY_GROUP_UNCOMMITED:
  67         case CATTA_ENTRY_GROUP_REGISTERING:
  68                 break;
  69         }
  70 }
  71
  72
  73 static void discovery_create_services(meshlink_handle_t *mesh) {
  74         char *fingerprint = NULL;
  75         char *txt_name = NULL;
  76         char *txt_fingerprint = NULL;
  77
  78         assert(mesh);
  79         assert(mesh->name);
  80         assert(mesh->myport);
  81         assert(mesh->catta_server);
  82         assert(mesh->catta_poll);
  83         assert(mesh->catta_servicetype);
  84         assert(mesh->self);
  85
  86         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  87
  88         /* Ifthis is the first time we're called, let's create a new entry group */
  89         if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  90                 logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  91                 goto fail;
  92         }
  93
  94         /* Create txt records */
  95         fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
  96         xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
  97         xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
  98
  99         /* Add the service */
 100         int ret = 0;
 101
 102         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) {
 103                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 104                 goto fail;
 105         }
 106
 107         /* Tell the server to register the service */
 108         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 109                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 110                 goto fail;
 111         }
 112
 113         goto done;
 114
 115 fail:
 116         catta_simple_poll_quit(mesh->catta_poll);
 117
 118 done:
 119         free(fingerprint);
 120         free(txt_name);
 121         free(txt_fingerprint);
 122 }
 123
 124 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 125         (void)server;
 126         meshlink_handle_t *mesh = userdata;
 127
 128         assert(mesh);
 129
 130         switch(state) {
 131         case CATTA_SERVER_RUNNING:
 132
 133                 /* The serve has startup successfully and registered its host
 134                  * name on the network, so it's time to create our services */
 135                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 136                         abort();
 137                 }
 138
 139                 if(!mesh->catta_group) {
 140                         discovery_create_services(mesh);
 141                 }
 142
 143                 pthread_mutex_unlock(&mesh->mutex);
 144
 145                 break;
 146
 147         case CATTA_SERVER_COLLISION: {
 148                 /* A host name collision happened. Let's pick a new name for the server */
 149                 char hostname[17];
 150                 generate_rand_string(mesh, hostname, sizeof(hostname));
 151
 152                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 153                         abort();
 154                 }
 155
 156                 assert(mesh->catta_server);
 157                 assert(mesh->catta_poll);
 158
 159                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 160
 161                 if(result < 0) {
 162                         catta_simple_poll_quit(mesh->catta_poll);
 163                 }
 164
 165                 pthread_mutex_unlock(&mesh->mutex);
 166         }
 167         break;
 168
 169         case CATTA_SERVER_REGISTERING:
 170                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 171                         abort();
 172                 }
 173
 174                 /* Let's drop our registered services. When the server is back
 175                  * in CATTA_SERVER_RUNNING state we will register them
 176                  * again with the new host name. */
 177                 if(mesh->catta_group) {
 178                         catta_s_entry_group_reset(mesh->catta_group);
 179                         mesh->catta_group = NULL;
 180                 }
 181
 182                 pthread_mutex_unlock(&mesh->mutex);
 183
 184                 break;
 185
 186         case CATTA_SERVER_FAILURE:
 187                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 188                         abort();
 189                 }
 190
 191                 assert(mesh->catta_server);
 192                 assert(mesh->catta_poll);
 193
 194                 /* Terminate on failure */
 195                 catta_simple_poll_quit(mesh->catta_poll);
 196
 197                 pthread_mutex_unlock(&mesh->mutex);
 198                 break;
 199
 200         case CATTA_SERVER_INVALID:
 201                 break;
 202         }
 203 }
 204
 205 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) {
 206         (void)interface_;
 207         (void)protocol;
 208         (void)flags;
 209         (void)name;
 210         (void)type;
 211         (void)domain;
 212         (void)host_name;
 213
 214         meshlink_handle_t *mesh = userdata;
 215
 216         assert(mesh);
 217
 218         if(event != CATTA_RESOLVER_FOUND) {
 219                 catta_s_service_resolver_free(resolver);
 220                 return;
 221         }
 222
 223         // retrieve fingerprint
 224         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 225         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 226
 227         if(node_name_li && node_fp_li) {
 228                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 229                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 230
 231                 if(node_name[0] == '=' && node_fp[0] == '=') {
 232                         if(pthread_mutex_lock(&mesh->mutex) != 0) {
 233                                 abort();
 234                         }
 235
 236                         node_name += 1;
 237
 238                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 239
 240                         if(node) {
 241                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 242
 243                                 sockaddr_t naddress;
 244                                 memset(&naddress, 0, sizeof(naddress));
 245
 246                                 switch(address->proto) {
 247                                 case CATTA_PROTO_INET: {
 248                                         naddress.in.sin_family = AF_INET;
 249                                         naddress.in.sin_port = htons(port);
 250                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 251                                 }
 252                                 break;
 253
 254                                 case CATTA_PROTO_INET6: {
 255                                         naddress.in6.sin6_family = AF_INET6;
 256                                         naddress.in6.sin6_port = htons(port);
 257                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 258                                 }
 259                                 break;
 260
 261                                 default:
 262                                         naddress.unknown.family = AF_UNKNOWN;
 263                                         break;
 264                                 }
 265
 266                                 if(naddress.unknown.family != AF_UNKNOWN) {
 267                                         node_t *n = (node_t *)node;
 268                                         connection_t *c = n->connection;
 269
 270                                         n->catta_address = naddress;
 271                                         node_add_recent_address(mesh, n, &naddress);
 272
 273                                         if(c && c->outgoing && !c->status.active) {
 274                                                 c->outgoing->timeout = 0;
 275
 276                                                 if(c->outgoing->ev.cb) {
 277                                                         timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
 278                                                                 0, 0
 279                                                         });
 280                                                 }
 281
 282                                                 c->last_ping_time = -3600;
 283                                         }
 284
 285                                 } else {
 286                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 287                                 }
 288                         } else {
 289                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 290                         }
 291
 292                         pthread_mutex_unlock(&mesh->mutex);
 293                 }
 294         }
 295
 296         catta_s_service_resolver_free(resolver);
 297 }
 298
 299 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) {
 300         (void)browser;
 301         (void)flags;
 302         meshlink_handle_t *mesh = userdata;
 303
 304         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 305         switch(event) {
 306         case CATTA_BROWSER_FAILURE:
 307                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 308                         abort();
 309                 }
 310
 311                 catta_simple_poll_quit(mesh->catta_poll);
 312                 pthread_mutex_unlock(&mesh->mutex);
 313                 break;
 314
 315         case CATTA_BROWSER_NEW:
 316                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 317                         abort();
 318                 }
 319
 320                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 321                 handle_network_change(mesh, ++mesh->catta_interfaces);
 322                 pthread_mutex_unlock(&mesh->mutex);
 323                 break;
 324
 325         case CATTA_BROWSER_REMOVE:
 326                 if(pthread_mutex_lock(&mesh->mutex) != 0) {
 327                         abort();
 328                 }
 329
 330                 handle_network_change(mesh, --mesh->catta_interfaces);
 331                 pthread_mutex_unlock(&mesh->mutex);
 332                 break;
 333
 334         case CATTA_BROWSER_ALL_FOR_NOW:
 335         case CATTA_BROWSER_CACHE_EXHAUSTED:
 336                 break;
 337         }
 338 }
 339
 340 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 341         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 342
 343         switch(level) {
 344         case CATTA_LOG_ERROR:
 345                 mlevel = MESHLINK_ERROR;
 346                 break;
 347
 348         case CATTA_LOG_WARN:
 349                 mlevel = MESHLINK_WARNING;
 350                 break;
 351
 352         case CATTA_LOG_NOTICE:
 353         case CATTA_LOG_INFO:
 354                 mlevel = MESHLINK_INFO;
 355                 break;
 356
 357         case CATTA_LOG_DEBUG:
 358         default:
 359                 mlevel = MESHLINK_DEBUG;
 360                 break;
 361         }
 362
 363         logger(NULL, mlevel, "%s\n", txt);
 364 }
 365
 366 static void *discovery_loop(void *userdata) {
 367         bool status = false;
 368         meshlink_handle_t *mesh = userdata;
 369         assert(mesh);
 370
 371         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 372                 abort();
 373         }
 374
 375         // handle catta logs
 376         catta_set_log_function(discovery_log_cb);
 377
 378         // create service type string
 379         char appname[strlen(mesh->appname) + 2];
 380         strcpy(appname, mesh->appname);
 381
 382         for(char *p = appname; *p; p++) {
 383                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 384                         *p = '_';
 385                 }
 386         }
 387
 388         if(!appname[1]) {
 389                 appname[1] = '_';
 390                 appname[2] = '\0';
 391         }
 392
 393         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 394         mesh->catta_servicetype = malloc(servicetype_strlen);
 395
 396         if(mesh->catta_servicetype == NULL) {
 397                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 398                 goto fail;
 399         }
 400
 401         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 402
 403         // Allocate discovery loop object
 404         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 405                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 406                 goto fail;
 407         }
 408
 409         // generate some unique host name (we actually do not care about it)
 410         char hostname[17];
 411         generate_rand_string(mesh, hostname, sizeof(hostname));
 412
 413         // Let's set the host name for this server.
 414         CattaServerConfig config;
 415         catta_server_config_init(&config);
 416         config.host_name = catta_strdup(hostname);
 417         config.publish_workstation = 0;
 418         config.disallow_other_stacks = 0;
 419         config.publish_hinfo = 0;
 420         config.publish_addresses = 1;
 421         config.publish_no_reverse = 1;
 422         config.allow_point_to_point = 1;
 423
 424         /* Allocate a new server */
 425         int error;
 426         const CattaPoll *poller = catta_simple_poll_get(mesh->catta_poll);
 427
 428         if(!poller) {
 429                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 430                 goto fail;
 431         }
 432
 433         mesh->catta_server = catta_server_new(poller, &config, discovery_server_callback, mesh, &error);
 434
 435         /* Free the configuration data */
 436         catta_server_config_free(&config);
 437
 438         /* Check whether creating the server object succeeded */
 439         if(!mesh->catta_server) {
 440                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 441                 goto fail;
 442         }
 443
 444         // Create the service browser
 445         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))) {
 446                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 447                 goto fail;
 448         }
 449
 450         status = true;
 451
 452 fail:
 453
 454         pthread_cond_broadcast(&mesh->discovery_cond);
 455         pthread_mutex_unlock(&mesh->discovery_mutex);
 456
 457         if(status) {
 458                 catta_simple_poll_loop(mesh->catta_poll);
 459         }
 460
 461         if(mesh->catta_browser) {
 462                 catta_s_service_browser_free(mesh->catta_browser);
 463                 mesh->catta_browser = NULL;
 464         }
 465
 466         if(mesh->catta_group) {
 467                 catta_s_entry_group_reset(mesh->catta_group);
 468                 catta_s_entry_group_free(mesh->catta_group);
 469                 mesh->catta_group = NULL;
 470         }
 471
 472         if(mesh->catta_server) {
 473                 catta_server_free(mesh->catta_server);
 474                 mesh->catta_server = NULL;
 475         }
 476
 477         if(mesh->catta_poll) {
 478                 catta_simple_poll_free(mesh->catta_poll);
 479                 mesh->catta_poll = NULL;
 480         }
 481
 482         if(mesh->catta_servicetype) {
 483                 free(mesh->catta_servicetype);
 484                 mesh->catta_servicetype = NULL;
 485         }
 486
 487         return NULL;
 488 }
 489
 490 #ifdef RTM_NEWADDR
 491 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 492         (void)flags;
 493         static time_t prev_update;
 494         meshlink_handle_t *mesh = data;
 495
 496         struct {
 497                 struct rt_msghdr rtm;
 498                 char data[2048];
 499         } msg;
 500
 501         while(true) {
 502                 msg.rtm.rtm_version = 0;
 503                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 504
 505                 if(result <= 0) {
 506                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 507                                 break;
 508                         }
 509
 510                         logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
 511                         io_set(loop, &mesh->pfroute_io, 0);
 512                 }
 513
 514                 if(msg.rtm.rtm_version != RTM_VERSION) {
 515                         logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
 516                         break;
 517                 }
 518
 519                 switch(msg.rtm.rtm_type) {
 520                 case RTM_IFINFO:
 521                 case RTM_NEWADDR:
 522                 case RTM_DELADDR:
 523                         if(loop->now.tv_sec > prev_update + 5) {
 524                                 prev_update = loop->now.tv_sec;
 525                                 handle_network_change(mesh, 1);
 526                         }
 527
 528                         break;
 529
 530                 default:
 531                         break;
 532                 }
 533         }
 534 }
 535 #endif
 536
 537 bool discovery_start(meshlink_handle_t *mesh) {
 538         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 539
 540         assert(mesh);
 541         assert(!mesh->catta_poll);
 542         assert(!mesh->catta_server);
 543         assert(!mesh->catta_browser);
 544         assert(!mesh->discovery_threadstarted);
 545         assert(!mesh->catta_servicetype);
 546
 547         if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
 548                 abort();
 549         }
 550
 551         // Start the discovery thread
 552         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 553                 pthread_mutex_unlock(&mesh->discovery_mutex);
 554                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 555                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 556                 return false;
 557         }
 558
 559         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 560         pthread_mutex_unlock(&mesh->discovery_mutex);
 561
 562         mesh->discovery_threadstarted = true;
 563
 564 #ifdef RTM_NEWADDR
 565         int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
 566
 567         if(sock != -1) {
 568                 io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
 569         } else {
 570                 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
 571         }
 572
 573 #endif
 574
 575         return true;
 576 }
 577
 578 void discovery_stop(meshlink_handle_t *mesh) {
 579         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 580
 581         assert(mesh);
 582
 583 #ifdef RTM_NEWADDR
 584
 585         if(mesh->pfroute_io.cb) {
 586                 close(mesh->pfroute_io.fd);
 587                 io_del(&mesh->loop, &mesh->pfroute_io);
 588         }
 589
 590 #endif
 591
 592         // Shut down
 593         if(mesh->catta_poll) {
 594                 catta_simple_poll_quit(mesh->catta_poll);
 595         }
 596
 597         // Wait for the discovery thread to finish
 598         if(mesh->discovery_threadstarted == true) {
 599                 if(pthread_join(mesh->discovery_thread, NULL) != 0) {
 600                         abort();
 601                 }
 602
 603                 mesh->discovery_threadstarted = false;
 604         }
 605
 606         mesh->catta_interfaces = 0;
 607 }