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

   1 #include <catta/core.h>
   2 #include <catta/lookup.h>
   3 #include <catta/publish.h>
   4 #include <catta/log.h>
   5 #include <catta/simple-watch.h>
   6 #include <catta/malloc.h>
   7 #include <catta/alternative.h>
   8 #include <catta/error.h>
   9
  10 #include "meshlink_internal.h"
  11 #include "discovery.h"
  12 #include "sockaddr.h"
  13 #include "logger.h"
  14 #include "node.h"
  15 #include "connection.h"
  16
  17 #include <pthread.h>
  18
  19 #include <netinet/in.h>
  20
  21 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  22 #define MESHLINK_MDNS_NAME_KEY "name"
  23 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  24
  25 static void generate_rand_string(char *buffer, size_t size) {
  26         for(size_t i = 0; i < (size - 1); ++i) {
  27                 buffer[i] = 'a' + (rand() % ('z' - 'a' + 1));
  28         }
  29
  30         buffer[size - 1] = '\0';
  31 }
  32
  33 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  34         (void)server;
  35         (void)group;
  36         meshlink_handle_t *mesh = userdata;
  37
  38         // asserts
  39         assert(mesh != NULL);
  40         assert(mesh->catta_server != NULL);
  41         assert(mesh->catta_poll != NULL);
  42
  43         pthread_mutex_lock(&(mesh->mesh_mutex));
  44
  45         /* Called whenever the entry group state changes */
  46         switch(state) {
  47         case CATTA_ENTRY_GROUP_ESTABLISHED:
  48                 /* The entry group has been established successfully */
  49                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  50                 break;
  51
  52         case CATTA_ENTRY_GROUP_COLLISION:
  53                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  54                 // @TODO can we just set a new name and retry?
  55                 break;
  56
  57         case CATTA_ENTRY_GROUP_FAILURE :
  58                 /* Some kind of failure happened while we were registering our services */
  59                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  60                 catta_simple_poll_quit(mesh->catta_poll);
  61                 break;
  62
  63         case CATTA_ENTRY_GROUP_UNCOMMITED:
  64         case CATTA_ENTRY_GROUP_REGISTERING:
  65                 ;
  66         }
  67
  68         pthread_mutex_unlock(&(mesh->mesh_mutex));
  69 }
  70
  71
  72 static void discovery_create_services(meshlink_handle_t *mesh) {
  73         char *txt_name = NULL;
  74
  75         // asserts
  76         assert(mesh != NULL);
  77         assert(mesh->name != NULL);
  78         assert(mesh->myport != NULL);
  79         assert(mesh->catta_server != NULL);
  80         assert(mesh->catta_poll != NULL);
  81         assert(mesh->catta_servicetype != NULL);
  82         assert(mesh->self != NULL);
  83
  84         pthread_mutex_lock(&(mesh->mesh_mutex));
  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) {
  90                 if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  91                         logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  92                         goto fail;
  93                 }
  94         }
  95
  96         /* Create txt records */
  97         size_t txt_name_len = sizeof(MESHLINK_MDNS_NAME_KEY) + 1 + strlen(mesh->name) + 1;
  98         txt_name = malloc(txt_name_len);
  99
 100         if(txt_name == NULL) {
 101                 logger(mesh, MESHLINK_ERROR, "Could not allocate memory for TXT record\n");
 102                 goto fail;
 103         }
 104
 105         snprintf(txt_name, txt_name_len, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
 106
 107         char txt_fingerprint[sizeof(MESHLINK_MDNS_FINGERPRINT_KEY) + 1 + MESHLINK_FINGERPRINTLEN + 1];
 108         snprintf(txt_fingerprint, sizeof(txt_fingerprint), "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self));
 109
 110         /* Add the service */
 111         int ret = 0;
 112
 113         if((ret = catta_server_add_service(mesh->catta_server, mesh->catta_group, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, 0, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self), mesh->catta_servicetype, NULL, NULL, atoi(mesh->myport), txt_name, txt_fingerprint, NULL)) < 0) {
 114                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 115                 goto fail;
 116         }
 117
 118         /* Tell the server to register the service */
 119         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 120                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 121                 goto fail;
 122         }
 123
 124         goto done;
 125
 126 fail:
 127         catta_simple_poll_quit(mesh->catta_poll);
 128
 129 done:
 130
 131         if(txt_name) {
 132                 free(txt_name);
 133         }
 134
 135         pthread_mutex_unlock(&(mesh->mesh_mutex));
 136 }
 137
 138 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 139         (void)server;
 140         meshlink_handle_t *mesh = userdata;
 141
 142         // asserts
 143         assert(mesh != NULL);
 144
 145         switch(state) {
 146         case CATTA_SERVER_RUNNING:
 147
 148                 /* The serve has startup successfully and registered its host
 149                  * name on the network, so it's time to create our services */
 150                 if(!mesh->catta_group) {
 151                         discovery_create_services(mesh);
 152                 }
 153
 154                 break;
 155
 156         case CATTA_SERVER_COLLISION: {
 157                 // asserts
 158                 assert(mesh->catta_server != NULL);
 159                 assert(mesh->catta_poll != NULL);
 160
 161                 /* A host name collision happened. Let's pick a new name for the server */
 162                 char hostname[17];
 163                 generate_rand_string(hostname, sizeof(hostname));
 164                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 165
 166                 if(result < 0) {
 167                         catta_simple_poll_quit(mesh->catta_poll);
 168                 }
 169         }
 170         break;
 171
 172         case CATTA_SERVER_REGISTERING:
 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                 break;
 183
 184         case CATTA_SERVER_FAILURE:
 185                 // asserts
 186                 assert(mesh->catta_server != NULL);
 187                 assert(mesh->catta_poll != NULL);
 188
 189                 /* Terminate on failure */
 190                 catta_simple_poll_quit(mesh->catta_poll);
 191                 break;
 192
 193         case CATTA_SERVER_INVALID:
 194                 break;
 195         }
 196 }
 197
 198 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) {
 199         (void)interface_;
 200         (void)protocol;
 201         (void)flags;
 202         meshlink_handle_t *mesh = userdata;
 203
 204         // asserts
 205         assert(resolver != NULL);
 206         assert(mesh != NULL);
 207         assert(mesh->catta_server != NULL);
 208
 209         /* Called whenever a service has been resolved successfully or timed out */
 210         switch(event) {
 211         case CATTA_RESOLVER_FAILURE:
 212                 // asserts
 213                 assert(name != NULL);
 214                 assert(type != NULL);
 215                 assert(domain != NULL);
 216                 break;
 217
 218         case CATTA_RESOLVER_FOUND: {
 219                 // asserts
 220                 assert(name != NULL);
 221                 assert(type != NULL);
 222                 assert(domain != NULL);
 223                 assert(host_name != NULL);
 224                 assert(address != NULL);
 225                 assert(txt != NULL);
 226
 227                 // retrieve fingerprint
 228                 CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 229                 CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 230
 231                 if(node_name_li != NULL && node_fp_li != NULL) {
 232                         char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 233                         char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 234
 235                         if(node_name[0] == '=' && node_fp[0] == '=') {
 236                                 pthread_mutex_lock(&(mesh->mesh_mutex));
 237
 238                                 node_name += 1;
 239                                 node_fp += 1;
 240
 241                                 meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 242
 243                                 if(node != NULL) {
 244                                         logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 245
 246                                         sockaddr_t naddress;
 247                                         memset(&naddress, 0, sizeof(naddress));
 248
 249                                         switch(address->proto) {
 250                                         case CATTA_PROTO_INET: {
 251                                                 naddress.in.sin_family = AF_INET;
 252                                                 naddress.in.sin_port = htons(port);
 253                                                 naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 254                                         }
 255                                         break;
 256
 257                                         case CATTA_PROTO_INET6: {
 258                                                 naddress.in6.sin6_family = AF_INET6;
 259                                                 naddress.in6.sin6_port = htons(port);
 260                                                 memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 261                                         }
 262                                         break;
 263
 264                                         default:
 265                                                 naddress.unknown.family = AF_UNKNOWN;
 266                                                 break;
 267                                         }
 268
 269                                         if(naddress.unknown.family != AF_UNKNOWN) {
 270                                                 meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 271                                                 pthread_mutex_lock(&(mesh->mesh_mutex));
 272
 273                                                 node_t *n = (node_t *)node;
 274
 275                                                 if(n->connection && n->connection->outgoing) {
 276                                                         n->connection->outgoing->timeout = 0;
 277
 278                                                         if(n->connection->outgoing->ev.cb) {
 279                                                                 timeout_set(&mesh->loop, &n->connection->outgoing->ev, &(struct timeval) {
 280                                                                         0, 0
 281                                                                 });
 282                                                         }
 283
 284                                                         n->connection->last_ping_time = 0;
 285                                                 }
 286
 287                                                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 288                                         } else {
 289                                                 logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 290                                         }
 291                                 } else {
 292                                         logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 293                                 }
 294
 295                                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 296                         }
 297                 }
 298         }
 299         break;
 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         // asserts
 311         assert(mesh != NULL);
 312         assert(mesh->catta_server != NULL);
 313         assert(mesh->catta_poll != NULL);
 314
 315         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 316         switch(event) {
 317         case CATTA_BROWSER_FAILURE:
 318                 catta_simple_poll_quit(mesh->catta_poll);
 319                 break;
 320
 321         case CATTA_BROWSER_NEW:
 322                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 323                 break;
 324
 325         case CATTA_BROWSER_REMOVE:
 326         case CATTA_BROWSER_ALL_FOR_NOW:
 327         case CATTA_BROWSER_CACHE_EXHAUSTED:
 328                 break;
 329         }
 330 }
 331
 332 static void *discovery_loop(void *userdata) {
 333         meshlink_handle_t *mesh = userdata;
 334
 335         // asserts
 336         assert(mesh != NULL);
 337         assert(mesh->catta_poll != NULL);
 338
 339         catta_simple_poll_loop(mesh->catta_poll);
 340
 341         return NULL;
 342 }
 343
 344 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 345         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 346
 347         switch(level) {
 348         case CATTA_LOG_ERROR:
 349                 mlevel = MESHLINK_ERROR;
 350                 break;
 351
 352         case CATTA_LOG_WARN:
 353                 mlevel = MESHLINK_WARNING;
 354                 break;
 355
 356         case CATTA_LOG_NOTICE:
 357         case CATTA_LOG_INFO:
 358                 mlevel = MESHLINK_INFO;
 359                 break;
 360
 361         case CATTA_LOG_DEBUG:
 362         default:
 363                 mlevel = MESHLINK_DEBUG;
 364                 break;
 365         }
 366
 367         logger(NULL, mlevel, "%s\n", txt);
 368 }
 369
 370 bool discovery_start(meshlink_handle_t *mesh) {
 371         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 372
 373         // asserts
 374         assert(mesh != NULL);
 375         assert(mesh->catta_poll == NULL);
 376         assert(mesh->catta_server == NULL);
 377         assert(mesh->catta_browser == NULL);
 378         assert(mesh->discovery_threadstarted == false);
 379         assert(mesh->catta_servicetype == NULL);
 380
 381         // handle catta logs
 382         catta_set_log_function(discovery_log_cb);
 383
 384         // create service type string
 385         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(mesh->appname) + 1;
 386         mesh->catta_servicetype = malloc(servicetype_strlen);
 387
 388         if(mesh->catta_servicetype == NULL) {
 389                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 390                 goto fail;
 391         }
 392
 393         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, mesh->appname);
 394
 395         // Allocate discovery loop object
 396         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 397                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 398                 goto fail;
 399         }
 400
 401         // generate some unique host name (we actually do not care about it)
 402         char hostname[17];
 403         generate_rand_string(hostname, sizeof(hostname));
 404
 405         // Let's set the host name for this server.
 406         CattaServerConfig config;
 407         catta_server_config_init(&config);
 408         config.host_name = catta_strdup(hostname);
 409         config.publish_workstation = 0;
 410         config.disallow_other_stacks = 0;
 411         config.publish_hinfo = 0;
 412         config.publish_addresses = 1;
 413         config.publish_no_reverse = 1;
 414
 415         /* Allocate a new server */
 416         int error;
 417         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 418
 419         /* Free the configuration data */
 420         catta_server_config_free(&config);
 421
 422         /* Check wether creating the server object succeeded */
 423         if(!mesh->catta_server) {
 424                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 425                 goto fail;
 426         }
 427
 428         // Create the service browser
 429         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))) {
 430                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 431                 goto fail;
 432         }
 433
 434         // Start the discovery thread
 435         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 436                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 437                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 438                 goto fail;
 439         }
 440
 441         mesh->discovery_threadstarted = true;
 442
 443         return true;
 444
 445 fail:
 446
 447         if(mesh->catta_browser != NULL) {
 448                 catta_s_service_browser_free(mesh->catta_browser);
 449                 mesh->catta_browser = NULL;
 450         }
 451
 452         if(mesh->catta_server != NULL) {
 453                 catta_server_free(mesh->catta_server);
 454                 mesh->catta_server = NULL;
 455         }
 456
 457         if(mesh->catta_poll != NULL) {
 458                 catta_simple_poll_free(mesh->catta_poll);
 459                 mesh->catta_poll = NULL;
 460         }
 461
 462         if(mesh->catta_servicetype != NULL) {
 463                 free(mesh->catta_servicetype);
 464                 mesh->catta_servicetype = NULL;
 465         }
 466
 467         return false;
 468 }
 469
 470 void discovery_stop(meshlink_handle_t *mesh) {
 471         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 472
 473         // asserts
 474         assert(mesh != NULL);
 475
 476         // Shut down
 477         if(mesh->catta_poll) {
 478                 catta_simple_poll_quit(mesh->catta_poll);
 479         }
 480
 481         // Wait for the discovery thread to finish
 482         if(mesh->discovery_threadstarted == true) {
 483                 pthread_join(mesh->discovery_thread, NULL);
 484                 mesh->discovery_threadstarted = false;
 485         }
 486
 487         // Clean up resources
 488         if(mesh->catta_browser != NULL) {
 489                 catta_s_service_browser_free(mesh->catta_browser);
 490                 mesh->catta_browser = NULL;
 491         }
 492
 493         if(mesh->catta_group) {
 494                 catta_s_entry_group_reset(mesh->catta_group);
 495                 catta_s_entry_group_free(mesh->catta_group);
 496                 mesh->catta_group = NULL;
 497         }
 498
 499         if(mesh->catta_server != NULL) {
 500                 catta_server_free(mesh->catta_server);
 501                 mesh->catta_server = NULL;
 502         }
 503
 504         if(mesh->catta_poll != NULL) {
 505                 catta_simple_poll_free(mesh->catta_poll);
 506                 mesh->catta_poll = NULL;
 507         }
 508
 509         if(mesh->catta_servicetype != NULL) {
 510                 free(mesh->catta_servicetype);
 511                 mesh->catta_servicetype = NULL;
 512         }
 513 }