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         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  82
  83         /* Ifthis is the first time we're called, let's create a new entry group */
  84         if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  85                 logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  86                 goto fail;
  87         }
  88
  89         /* Create txt records */
  90         fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
  91         xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
  92         xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
  93
  94         /* Add the service */
  95         int ret = 0;
  96
  97         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) {
  98                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
  99                 goto fail;
 100         }
 101
 102         /* Tell the server to register the service */
 103         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 104                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 105                 goto fail;
 106         }
 107
 108         goto done;
 109
 110 fail:
 111         catta_simple_poll_quit(mesh->catta_poll);
 112
 113 done:
 114         free(fingerprint);
 115         free(txt_name);
 116         free(txt_fingerprint);
 117
 118         pthread_mutex_unlock(&(mesh->mesh_mutex));
 119 }
 120
 121 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 122         (void)server;
 123         meshlink_handle_t *mesh = userdata;
 124
 125         // asserts
 126         assert(mesh != NULL);
 127
 128         switch(state) {
 129         case CATTA_SERVER_RUNNING:
 130                 /* The serve has startup successfully and registered its host
 131                  * name on the network, so it's time to create our services */
 132                 pthread_mutex_lock(&(mesh->mesh_mutex));
 133
 134                 if(!mesh->catta_group) {
 135                         discovery_create_services(mesh);
 136                 }
 137
 138                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 139
 140                 break;
 141
 142         case CATTA_SERVER_COLLISION: {
 143                 /* A host name collision happened. Let's pick a new name for the server */
 144                 char hostname[17];
 145                 generate_rand_string(hostname, sizeof(hostname));
 146
 147                 pthread_mutex_lock(&(mesh->mesh_mutex));
 148                 //
 149                 // asserts
 150                 assert(mesh->catta_server != NULL);
 151                 assert(mesh->catta_poll != NULL);
 152
 153                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 154
 155                 if(result < 0) {
 156                         catta_simple_poll_quit(mesh->catta_poll);
 157                 }
 158
 159                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 160         }
 161         break;
 162
 163         case CATTA_SERVER_REGISTERING:
 164                 pthread_mutex_lock(&(mesh->mesh_mutex));
 165
 166                 /* Let's drop our registered services. When the server is back
 167                  * in CATTA_SERVER_RUNNING state we will register them
 168                  * again with the new host name. */
 169                 if(mesh->catta_group) {
 170                         catta_s_entry_group_reset(mesh->catta_group);
 171                         mesh->catta_group = NULL;
 172                 }
 173
 174                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 175
 176                 break;
 177
 178         case CATTA_SERVER_FAILURE:
 179                 pthread_mutex_lock(&(mesh->mesh_mutex));
 180
 181                 // asserts
 182                 assert(mesh->catta_server != NULL);
 183                 assert(mesh->catta_poll != NULL);
 184
 185                 /* Terminate on failure */
 186                 catta_simple_poll_quit(mesh->catta_poll);
 187
 188                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 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         (void)name;
 201         (void)type;
 202         (void)domain;
 203         (void)host_name;
 204
 205         meshlink_handle_t *mesh = userdata;
 206
 207         if(event != CATTA_RESOLVER_FOUND) {
 208                 catta_s_service_resolver_free(resolver);
 209                 return;
 210         }
 211
 212         // retrieve fingerprint
 213         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 214         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 215
 216         if(node_name_li != NULL && node_fp_li != NULL) {
 217                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 218                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 219
 220                 if(node_name[0] == '=' && node_fp[0] == '=') {
 221                         pthread_mutex_lock(&(mesh->mesh_mutex));
 222
 223                         node_name += 1;
 224
 225                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 226
 227                         if(node != NULL) {
 228                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 229
 230                                 sockaddr_t naddress;
 231                                 memset(&naddress, 0, sizeof(naddress));
 232
 233                                 switch(address->proto) {
 234                                 case CATTA_PROTO_INET: {
 235                                         naddress.in.sin_family = AF_INET;
 236                                         naddress.in.sin_port = htons(port);
 237                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 238                                 }
 239                                 break;
 240
 241                                 case CATTA_PROTO_INET6: {
 242                                         naddress.in6.sin6_family = AF_INET6;
 243                                         naddress.in6.sin6_port = htons(port);
 244                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 245                                 }
 246                                 break;
 247
 248                                 default:
 249                                         naddress.unknown.family = AF_UNKNOWN;
 250                                         break;
 251                                 }
 252
 253                                 if(naddress.unknown.family != AF_UNKNOWN) {
 254                                         meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 255
 256                                         node_t *n = (node_t *)node;
 257
 258                                         if(n->connection && n->connection->outgoing) {
 259                                                 n->connection->outgoing->timeout = 0;
 260
 261                                                 if(n->connection->outgoing->ev.cb) {
 262                                                         timeout_set(&mesh->loop, &n->connection->outgoing->ev, &(struct timeval) {
 263                                                                 0, 0
 264                                                         });
 265                                                 }
 266
 267                                                 n->connection->last_ping_time = 0;
 268                                         }
 269
 270                                 } else {
 271                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 272                                 }
 273                         } else {
 274                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 275                         }
 276
 277                         pthread_mutex_unlock(&(mesh->mesh_mutex));
 278                 }
 279         }
 280
 281         catta_s_service_resolver_free(resolver);
 282 }
 283
 284 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) {
 285         (void)browser;
 286         (void)flags;
 287         meshlink_handle_t *mesh = userdata;
 288
 289         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 290         switch(event) {
 291         case CATTA_BROWSER_FAILURE:
 292                 pthread_mutex_lock(&mesh->mesh_mutex);
 293                 catta_simple_poll_quit(mesh->catta_poll);
 294                 pthread_mutex_unlock(&mesh->mesh_mutex);
 295                 break;
 296
 297         case CATTA_BROWSER_NEW:
 298                 pthread_mutex_lock(&mesh->mesh_mutex);
 299                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 300                 handle_network_change(mesh, ++mesh->catta_interfaces);
 301                 pthread_mutex_unlock(&mesh->mesh_mutex);
 302                 break;
 303
 304         case CATTA_BROWSER_REMOVE:
 305                 pthread_mutex_lock(&mesh->mesh_mutex);
 306                 handle_network_change(mesh, --mesh->catta_interfaces);
 307                 pthread_mutex_unlock(&mesh->mesh_mutex);
 308                 break;
 309
 310         case CATTA_BROWSER_ALL_FOR_NOW:
 311         case CATTA_BROWSER_CACHE_EXHAUSTED:
 312                 break;
 313         }
 314 }
 315
 316 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 317         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 318
 319         switch(level) {
 320         case CATTA_LOG_ERROR:
 321                 mlevel = MESHLINK_ERROR;
 322                 break;
 323
 324         case CATTA_LOG_WARN:
 325                 mlevel = MESHLINK_WARNING;
 326                 break;
 327
 328         case CATTA_LOG_NOTICE:
 329         case CATTA_LOG_INFO:
 330                 mlevel = MESHLINK_INFO;
 331                 break;
 332
 333         case CATTA_LOG_DEBUG:
 334         default:
 335                 mlevel = MESHLINK_DEBUG;
 336                 break;
 337         }
 338
 339         logger(NULL, mlevel, "%s\n", txt);
 340 }
 341
 342 static void *discovery_loop(void *userdata) {
 343         bool status = false;
 344         meshlink_handle_t *mesh = userdata;
 345         assert(mesh != NULL);
 346
 347         // handle catta logs
 348         catta_set_log_function(discovery_log_cb);
 349
 350         // create service type string
 351         char appname[strlen(mesh->appname) + 2];
 352         strcpy(appname, mesh->appname);
 353
 354         for(char *p = appname; *p; p++) {
 355                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 356                         *p = '_';
 357                 }
 358         }
 359
 360         if(!appname[1]) {
 361                 appname[1] = '_';
 362                 appname[2] = '\0';
 363         }
 364
 365         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 366         mesh->catta_servicetype = malloc(servicetype_strlen);
 367
 368         if(mesh->catta_servicetype == NULL) {
 369                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 370                 goto fail;
 371         }
 372
 373         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 374
 375         // Allocate discovery loop object
 376         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 377                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 378                 goto fail;
 379         }
 380
 381         // generate some unique host name (we actually do not care about it)
 382         char hostname[17];
 383         generate_rand_string(hostname, sizeof(hostname));
 384
 385         // Let's set the host name for this server.
 386         CattaServerConfig config;
 387         catta_server_config_init(&config);
 388         config.host_name = catta_strdup(hostname);
 389         config.publish_workstation = 0;
 390         config.disallow_other_stacks = 0;
 391         config.publish_hinfo = 0;
 392         config.publish_addresses = 1;
 393         config.publish_no_reverse = 1;
 394
 395         /* Allocate a new server */
 396         int error;
 397         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 398
 399         /* Free the configuration data */
 400         catta_server_config_free(&config);
 401
 402         /* Check wether creating the server object succeeded */
 403         if(!mesh->catta_server) {
 404                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 405                 goto fail;
 406         }
 407
 408         // Create the service browser
 409         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))) {
 410                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 411                 goto fail;
 412         }
 413
 414         status = true;
 415
 416 fail:
 417
 418         pthread_mutex_lock(&mesh->discovery_mutex);
 419         pthread_cond_broadcast(&mesh->discovery_cond);
 420         pthread_mutex_unlock(&mesh->discovery_mutex);
 421
 422         if(status) {
 423                 catta_simple_poll_loop(mesh->catta_poll);
 424         }
 425
 426         if(mesh->catta_browser != NULL) {
 427                 catta_s_service_browser_free(mesh->catta_browser);
 428                 mesh->catta_browser = NULL;
 429         }
 430
 431         if(mesh->catta_group) {
 432                 catta_s_entry_group_reset(mesh->catta_group);
 433                 catta_s_entry_group_free(mesh->catta_group);
 434                 mesh->catta_group = NULL;
 435         }
 436
 437         if(mesh->catta_server != NULL) {
 438                 catta_server_free(mesh->catta_server);
 439                 mesh->catta_server = NULL;
 440         }
 441
 442         if(mesh->catta_poll != NULL) {
 443                 catta_simple_poll_free(mesh->catta_poll);
 444                 mesh->catta_poll = NULL;
 445         }
 446
 447         if(mesh->catta_servicetype != NULL) {
 448                 free(mesh->catta_servicetype);
 449                 mesh->catta_servicetype = NULL;
 450         }
 451
 452         return NULL;
 453 }
 454
 455 bool discovery_start(meshlink_handle_t *mesh) {
 456         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 457
 458         // asserts
 459         assert(mesh != NULL);
 460         assert(mesh->catta_poll == NULL);
 461         assert(mesh->catta_server == NULL);
 462         assert(mesh->catta_browser == NULL);
 463         assert(mesh->discovery_threadstarted == false);
 464         assert(mesh->catta_servicetype == NULL);
 465
 466         // Start the discovery thread
 467         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 468                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 469                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 470                 return false;
 471         }
 472
 473         pthread_mutex_lock(&mesh->discovery_mutex);
 474         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 475         pthread_mutex_unlock(&mesh->discovery_mutex);
 476
 477         mesh->discovery_threadstarted = true;
 478
 479         return true;
 480 }
 481
 482 void discovery_stop(meshlink_handle_t *mesh) {
 483         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 484
 485         // asserts
 486         assert(mesh != NULL);
 487
 488         // Shut down
 489         if(mesh->catta_poll) {
 490                 catta_simple_poll_quit(mesh->catta_poll);
 491         }
 492
 493         // Wait for the discovery thread to finish
 494         if(mesh->discovery_threadstarted == true) {
 495                 pthread_join(mesh->discovery_thread, NULL);
 496                 mesh->discovery_threadstarted = false;
 497         }
 498
 499         mesh->catta_interfaces = 0;
 500 }