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