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
  15 #include <pthread.h>
  16
  17 #include <netinet/in.h>
  18
  19 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  20 #define MESHLINK_MDNS_NAME_KEY "name"
  21 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  22
  23 static void generate_rand_string(char *buffer, size_t size) {
  24         for(size_t i = 0; i < (size - 1); ++i) {
  25                 buffer[i] = 'a' + (rand() % ('z' - 'a' + 1));
  26         }
  27
  28         buffer[size - 1] = '\0';
  29 }
  30
  31 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  32         (void)server;
  33         (void)group;
  34         meshlink_handle_t *mesh = userdata;
  35
  36         // asserts
  37         assert(mesh != NULL);
  38         assert(mesh->catta_server != NULL);
  39         assert(mesh->catta_poll != NULL);
  40
  41         pthread_mutex_lock(&(mesh->mesh_mutex));
  42
  43         /* Called whenever the entry group state changes */
  44         switch(state) {
  45         case CATTA_ENTRY_GROUP_ESTABLISHED:
  46                 /* The entry group has been established successfully */
  47                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  48                 break;
  49
  50         case CATTA_ENTRY_GROUP_COLLISION:
  51                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  52                 // @TODO can we just set a new name and retry?
  53                 break;
  54
  55         case CATTA_ENTRY_GROUP_FAILURE :
  56                 /* Some kind of failure happened while we were registering our services */
  57                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  58                 catta_simple_poll_quit(mesh->catta_poll);
  59                 break;
  60
  61         case CATTA_ENTRY_GROUP_UNCOMMITED:
  62         case CATTA_ENTRY_GROUP_REGISTERING:
  63                 ;
  64         }
  65
  66         pthread_mutex_unlock(&(mesh->mesh_mutex));
  67 }
  68
  69
  70 static void discovery_create_services(meshlink_handle_t *mesh) {
  71         char *txt_name = NULL;
  72
  73         // asserts
  74         assert(mesh != NULL);
  75         assert(mesh->name != NULL);
  76         assert(mesh->myport != NULL);
  77         assert(mesh->catta_server != NULL);
  78         assert(mesh->catta_poll != NULL);
  79         assert(mesh->catta_servicetype != NULL);
  80         assert(mesh->self != NULL);
  81
  82         pthread_mutex_lock(&(mesh->mesh_mutex));
  83
  84         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  85
  86         /* Ifthis is the first time we're called, let's create a new entry group */
  87         if(!mesh->catta_group) {
  88                 if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  89                         logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  90                         goto fail;
  91                 }
  92         }
  93
  94         /* Create txt records */
  95         size_t txt_name_len = sizeof(MESHLINK_MDNS_NAME_KEY) + 1 + strlen(mesh->name) + 1;
  96         txt_name = malloc(txt_name_len);
  97
  98         if(txt_name == NULL) {
  99                 logger(mesh, MESHLINK_ERROR, "Could not allocate memory for TXT record\n");
 100                 goto fail;
 101         }
 102
 103         snprintf(txt_name, txt_name_len, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
 104
 105         char txt_fingerprint[sizeof(MESHLINK_MDNS_FINGERPRINT_KEY) + 1 + MESHLINK_FINGERPRINTLEN + 1];
 106         snprintf(txt_fingerprint, sizeof(txt_fingerprint), "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self));
 107
 108         /* Add the service */
 109         int ret = 0;
 110
 111         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) {
 112                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 113                 goto fail;
 114         }
 115
 116         /* Tell the server to register the service */
 117         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 118                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 119                 goto fail;
 120         }
 121
 122         goto done;
 123
 124 fail:
 125         catta_simple_poll_quit(mesh->catta_poll);
 126
 127 done:
 128
 129         if(txt_name) {
 130                 free(txt_name);
 131         }
 132
 133         pthread_mutex_unlock(&(mesh->mesh_mutex));
 134 }
 135
 136 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 137         (void)server;
 138         meshlink_handle_t *mesh = userdata;
 139
 140         // asserts
 141         assert(mesh != NULL);
 142
 143         switch(state) {
 144         case CATTA_SERVER_RUNNING:
 145
 146                 /* The serve has startup successfully and registered its host
 147                  * name on the network, so it's time to create our services */
 148                 if(!mesh->catta_group) {
 149                         discovery_create_services(mesh);
 150                 }
 151
 152                 break;
 153
 154         case CATTA_SERVER_COLLISION: {
 155                 // asserts
 156                 assert(mesh->catta_server != NULL);
 157                 assert(mesh->catta_poll != NULL);
 158
 159                 /* A host name collision happened. Let's pick a new name for the server */
 160                 char hostname[17];
 161                 generate_rand_string(hostname, sizeof(hostname));
 162                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 163
 164                 if(result < 0) {
 165                         catta_simple_poll_quit(mesh->catta_poll);
 166                 }
 167         }
 168         break;
 169
 170         case CATTA_SERVER_REGISTERING:
 171
 172                 /* Let's drop our registered services. When the server is back
 173                  * in CATTA_SERVER_RUNNING state we will register them
 174                  * again with the new host name. */
 175                 if(mesh->catta_group) {
 176                         catta_s_entry_group_reset(mesh->catta_group);
 177                         mesh->catta_group = NULL;
 178                 }
 179
 180                 break;
 181
 182         case CATTA_SERVER_FAILURE:
 183                 // asserts
 184                 assert(mesh->catta_server != NULL);
 185                 assert(mesh->catta_poll != NULL);
 186
 187                 /* Terminate on failure */
 188                 catta_simple_poll_quit(mesh->catta_poll);
 189                 break;
 190
 191         case CATTA_SERVER_INVALID:
 192                 break;
 193         }
 194 }
 195
 196 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) {
 197         (void)interface_;
 198         (void)protocol;
 199         (void)flags;
 200         meshlink_handle_t *mesh = userdata;
 201
 202         // asserts
 203         assert(resolver != NULL);
 204         assert(mesh != NULL);
 205         assert(mesh->catta_server != NULL);
 206
 207         /* Called whenever a service has been resolved successfully or timed out */
 208         switch(event) {
 209         case CATTA_RESOLVER_FAILURE:
 210                 // asserts
 211                 assert(name != NULL);
 212                 assert(type != NULL);
 213                 assert(domain != NULL);
 214                 break;
 215
 216         case CATTA_RESOLVER_FOUND: {
 217                 // asserts
 218                 assert(name != NULL);
 219                 assert(type != NULL);
 220                 assert(domain != NULL);
 221                 assert(host_name != NULL);
 222                 assert(address != NULL);
 223                 assert(txt != NULL);
 224
 225                 // retrieve fingerprint
 226                 CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 227                 CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 228
 229                 if(node_name_li != NULL && node_fp_li != NULL) {
 230                         char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 231                         char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 232
 233                         if(node_name[0] == '=' && node_fp[0] == '=') {
 234                                 pthread_mutex_lock(&(mesh->mesh_mutex));
 235
 236                                 node_name += 1;
 237                                 node_fp += 1;
 238
 239                                 meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 240
 241                                 if(node != NULL) {
 242                                         logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 243
 244                                         sockaddr_t naddress;
 245                                         memset(&naddress, 0, sizeof(naddress));
 246
 247                                         switch(address->proto) {
 248                                         case CATTA_PROTO_INET: {
 249                                                 naddress.in.sin_family = AF_INET;
 250                                                 naddress.in.sin_port = htons(port);
 251                                                 naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 252                                         }
 253                                         break;
 254
 255                                         case CATTA_PROTO_INET6: {
 256                                                 naddress.in6.sin6_family = AF_INET6;
 257                                                 naddress.in6.sin6_port = htons(port);
 258                                                 memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 259                                         }
 260                                         break;
 261
 262                                         default:
 263                                                 naddress.unknown.family = AF_UNKNOWN;
 264                                                 break;
 265                                         }
 266
 267                                         if(naddress.unknown.family != AF_UNKNOWN) {
 268                                                 meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 269                                         } else {
 270                                                 logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 271                                         }
 272                                 } else {
 273                                         logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 274                                 }
 275
 276                                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 277                         }
 278                 }
 279         }
 280         break;
 281         }
 282
 283         catta_s_service_resolver_free(resolver);
 284 }
 285
 286 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) {
 287         (void)browser;
 288         (void)flags;
 289         meshlink_handle_t *mesh = userdata;
 290
 291         // asserts
 292         assert(mesh != NULL);
 293         assert(mesh->catta_server != NULL);
 294         assert(mesh->catta_poll != NULL);
 295
 296         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 297         switch(event) {
 298         case CATTA_BROWSER_FAILURE:
 299                 catta_simple_poll_quit(mesh->catta_poll);
 300                 break;
 301
 302         case CATTA_BROWSER_NEW:
 303                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 304                 break;
 305
 306         case CATTA_BROWSER_REMOVE:
 307         case CATTA_BROWSER_ALL_FOR_NOW:
 308         case CATTA_BROWSER_CACHE_EXHAUSTED:
 309                 break;
 310         }
 311 }
 312
 313 static void *discovery_loop(void *userdata) {
 314         meshlink_handle_t *mesh = userdata;
 315
 316         // asserts
 317         assert(mesh != NULL);
 318         assert(mesh->catta_poll != NULL);
 319
 320         catta_simple_poll_loop(mesh->catta_poll);
 321
 322         return NULL;
 323 }
 324
 325 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 326         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 327
 328         switch(level) {
 329         case CATTA_LOG_ERROR:
 330                 mlevel = MESHLINK_ERROR;
 331                 break;
 332
 333         case CATTA_LOG_WARN:
 334                 mlevel = MESHLINK_WARNING;
 335                 break;
 336
 337         case CATTA_LOG_NOTICE:
 338         case CATTA_LOG_INFO:
 339                 mlevel = MESHLINK_INFO;
 340                 break;
 341
 342         case CATTA_LOG_DEBUG:
 343         default:
 344                 mlevel = MESHLINK_DEBUG;
 345                 break;
 346         }
 347
 348         logger(NULL, mlevel, "%s\n", txt);
 349 }
 350
 351 bool discovery_start(meshlink_handle_t *mesh) {
 352         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 353
 354         // asserts
 355         assert(mesh != NULL);
 356         assert(mesh->catta_poll == NULL);
 357         assert(mesh->catta_server == NULL);
 358         assert(mesh->catta_browser == NULL);
 359         assert(mesh->discovery_threadstarted == false);
 360         assert(mesh->catta_servicetype == NULL);
 361
 362         // handle catta logs
 363         catta_set_log_function(discovery_log_cb);
 364
 365         // create service type string
 366         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(mesh->appname) + 1;
 367         mesh->catta_servicetype = malloc(servicetype_strlen);
 368
 369         if(mesh->catta_servicetype == NULL) {
 370                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 371                 goto fail;
 372         }
 373
 374         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, mesh->appname);
 375
 376         // Allocate discovery loop object
 377         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 378                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 379                 goto fail;
 380         }
 381
 382         // generate some unique host name (we actually do not care about it)
 383         char hostname[17];
 384         generate_rand_string(hostname, sizeof(hostname));
 385
 386         // Let's set the host name for this server.
 387         CattaServerConfig config;
 388         catta_server_config_init(&config);
 389         config.host_name = catta_strdup(hostname);
 390         config.publish_workstation = 0;
 391         config.disallow_other_stacks = 0;
 392         config.publish_hinfo = 0;
 393         config.publish_addresses = 1;
 394         config.publish_no_reverse = 1;
 395
 396         /* Allocate a new server */
 397         int error;
 398         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 399
 400         /* Free the configuration data */
 401         catta_server_config_free(&config);
 402
 403         /* Check wether creating the server object succeeded */
 404         if(!mesh->catta_server) {
 405                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 406                 goto fail;
 407         }
 408
 409         // Create the service browser
 410         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))) {
 411                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 412                 goto fail;
 413         }
 414
 415         // Start the discovery thread
 416         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 417                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 418                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 419                 goto fail;
 420         }
 421
 422         mesh->discovery_threadstarted = true;
 423
 424         return true;
 425
 426 fail:
 427
 428         if(mesh->catta_browser != NULL) {
 429                 catta_s_service_browser_free(mesh->catta_browser);
 430                 mesh->catta_browser = NULL;
 431         }
 432
 433         if(mesh->catta_server != NULL) {
 434                 catta_server_free(mesh->catta_server);
 435                 mesh->catta_server = NULL;
 436         }
 437
 438         if(mesh->catta_poll != NULL) {
 439                 catta_simple_poll_free(mesh->catta_poll);
 440                 mesh->catta_poll = NULL;
 441         }
 442
 443         if(mesh->catta_servicetype != NULL) {
 444                 free(mesh->catta_servicetype);
 445                 mesh->catta_servicetype = NULL;
 446         }
 447
 448         return false;
 449 }
 450
 451 void discovery_stop(meshlink_handle_t *mesh) {
 452         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 453
 454         // asserts
 455         assert(mesh != NULL);
 456
 457         // Shut down
 458         if(mesh->catta_poll) {
 459                 catta_simple_poll_quit(mesh->catta_poll);
 460         }
 461
 462         // Wait for the discovery thread to finish
 463         if(mesh->discovery_threadstarted == true) {
 464                 pthread_join(mesh->discovery_thread, NULL);
 465                 mesh->discovery_threadstarted = false;
 466         }
 467
 468         // Clean up resources
 469         if(mesh->catta_browser != NULL) {
 470                 catta_s_service_browser_free(mesh->catta_browser);
 471                 mesh->catta_browser = NULL;
 472         }
 473
 474         if(mesh->catta_group) {
 475                 catta_s_entry_group_reset(mesh->catta_group);
 476                 catta_s_entry_group_free(mesh->catta_group);
 477                 mesh->catta_group = NULL;
 478         }
 479
 480         if(mesh->catta_server != NULL) {
 481                 catta_server_free(mesh->catta_server);
 482                 mesh->catta_server = NULL;
 483         }
 484
 485         if(mesh->catta_poll != NULL) {
 486                 catta_simple_poll_free(mesh->catta_poll);
 487                 mesh->catta_poll = NULL;
 488         }
 489
 490         if(mesh->catta_servicetype != NULL) {
 491                 free(mesh->catta_servicetype);
 492                 mesh->catta_servicetype = NULL;
 493         }
 494 }