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                         node_fp += 1;
 225
 226                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 227
 228                         if(node != NULL) {
 229                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 230
 231                                 sockaddr_t naddress;
 232                                 memset(&naddress, 0, sizeof(naddress));
 233
 234                                 switch(address->proto) {
 235                                 case CATTA_PROTO_INET: {
 236                                         naddress.in.sin_family = AF_INET;
 237                                         naddress.in.sin_port = htons(port);
 238                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 239                                 }
 240                                 break;
 241
 242                                 case CATTA_PROTO_INET6: {
 243                                         naddress.in6.sin6_family = AF_INET6;
 244                                         naddress.in6.sin6_port = htons(port);
 245                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 246                                 }
 247                                 break;
 248
 249                                 default:
 250                                         naddress.unknown.family = AF_UNKNOWN;
 251                                         break;
 252                                 }
 253
 254                                 if(naddress.unknown.family != AF_UNKNOWN) {
 255                                         meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 256
 257                                         node_t *n = (node_t *)node;
 258
 259                                         if(n->connection && n->connection->outgoing) {
 260                                                 n->connection->outgoing->timeout = 0;
 261
 262                                                 if(n->connection->outgoing->ev.cb) {
 263                                                         timeout_set(&mesh->loop, &n->connection->outgoing->ev, &(struct timeval) {
 264                                                                 0, 0
 265                                                         });
 266                                                 }
 267
 268                                                 n->connection->last_ping_time = 0;
 269                                         }
 270
 271                                 } else {
 272                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 273                                 }
 274                         } else {
 275                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 276                         }
 277
 278                         pthread_mutex_unlock(&(mesh->mesh_mutex));
 279                 }
 280         }
 281
 282         catta_s_service_resolver_free(resolver);
 283 }
 284
 285 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) {
 286         (void)browser;
 287         (void)flags;
 288         meshlink_handle_t *mesh = userdata;
 289
 290         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 291         switch(event) {
 292         case CATTA_BROWSER_FAILURE:
 293                 pthread_mutex_lock(&mesh->mesh_mutex);
 294                 catta_simple_poll_quit(mesh->catta_poll);
 295                 pthread_mutex_unlock(&mesh->mesh_mutex);
 296                 break;
 297
 298         case CATTA_BROWSER_NEW:
 299                 pthread_mutex_lock(&mesh->mesh_mutex);
 300                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 301                 handle_network_change(mesh, ++mesh->catta_interfaces);
 302                 pthread_mutex_unlock(&mesh->mesh_mutex);
 303                 break;
 304
 305         case CATTA_BROWSER_REMOVE:
 306                 pthread_mutex_lock(&mesh->mesh_mutex);
 307                 handle_network_change(mesh, --mesh->catta_interfaces);
 308                 pthread_mutex_unlock(&mesh->mesh_mutex);
 309                 break;
 310
 311         case CATTA_BROWSER_ALL_FOR_NOW:
 312         case CATTA_BROWSER_CACHE_EXHAUSTED:
 313                 break;
 314         }
 315 }
 316
 317 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 318         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 319
 320         switch(level) {
 321         case CATTA_LOG_ERROR:
 322                 mlevel = MESHLINK_ERROR;
 323                 break;
 324
 325         case CATTA_LOG_WARN:
 326                 mlevel = MESHLINK_WARNING;
 327                 break;
 328
 329         case CATTA_LOG_NOTICE:
 330         case CATTA_LOG_INFO:
 331                 mlevel = MESHLINK_INFO;
 332                 break;
 333
 334         case CATTA_LOG_DEBUG:
 335         default:
 336                 mlevel = MESHLINK_DEBUG;
 337                 break;
 338         }
 339
 340         logger(NULL, mlevel, "%s\n", txt);
 341 }
 342
 343 static void *discovery_loop(void *userdata) {
 344         bool status = false;
 345         meshlink_handle_t *mesh = userdata;
 346         assert(mesh != NULL);
 347
 348         // handle catta logs
 349         catta_set_log_function(discovery_log_cb);
 350
 351         // create service type string
 352         char appname[strlen(mesh->appname) + 2];
 353         strcpy(appname, mesh->appname);
 354
 355         for(char *p = appname; *p; p++) {
 356                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 357                         *p = '_';
 358                 }
 359         }
 360
 361         if(!appname[1]) {
 362                 appname[1] = '_';
 363                 appname[2] = '\0';
 364         }
 365
 366         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(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, 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         status = true;
 416
 417 fail:
 418
 419         pthread_mutex_lock(&mesh->discovery_mutex);
 420         pthread_cond_broadcast(&mesh->discovery_cond);
 421         pthread_mutex_unlock(&mesh->discovery_mutex);
 422
 423         if(status) {
 424                 catta_simple_poll_loop(mesh->catta_poll);
 425         }
 426
 427         if(mesh->catta_browser != NULL) {
 428                 catta_s_service_browser_free(mesh->catta_browser);
 429                 mesh->catta_browser = NULL;
 430         }
 431
 432         if(mesh->catta_group) {
 433                 catta_s_entry_group_reset(mesh->catta_group);
 434                 catta_s_entry_group_free(mesh->catta_group);
 435                 mesh->catta_group = NULL;
 436         }
 437
 438         if(mesh->catta_server != NULL) {
 439                 catta_server_free(mesh->catta_server);
 440                 mesh->catta_server = NULL;
 441         }
 442
 443         if(mesh->catta_poll != NULL) {
 444                 catta_simple_poll_free(mesh->catta_poll);
 445                 mesh->catta_poll = NULL;
 446         }
 447
 448         if(mesh->catta_servicetype != NULL) {
 449                 free(mesh->catta_servicetype);
 450                 mesh->catta_servicetype = NULL;
 451         }
 452
 453         return NULL;
 454 }
 455
 456 bool discovery_start(meshlink_handle_t *mesh) {
 457         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 458
 459         // asserts
 460         assert(mesh != NULL);
 461         assert(mesh->catta_poll == NULL);
 462         assert(mesh->catta_server == NULL);
 463         assert(mesh->catta_browser == NULL);
 464         assert(mesh->discovery_threadstarted == false);
 465         assert(mesh->catta_servicetype == NULL);
 466
 467         // Start the discovery thread
 468         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 469                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 470                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 471                 return false;
 472         }
 473
 474         pthread_mutex_lock(&mesh->discovery_mutex);
 475         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 476         pthread_mutex_unlock(&mesh->discovery_mutex);
 477
 478         mesh->discovery_threadstarted = true;
 479
 480         return true;
 481 }
 482
 483 void discovery_stop(meshlink_handle_t *mesh) {
 484         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 485
 486         // asserts
 487         assert(mesh != NULL);
 488
 489         // Shut down
 490         if(mesh->catta_poll) {
 491                 catta_simple_poll_quit(mesh->catta_poll);
 492         }
 493
 494         // Wait for the discovery thread to finish
 495         if(mesh->discovery_threadstarted == true) {
 496                 pthread_join(mesh->discovery_thread, NULL);
 497                 mesh->discovery_threadstarted = false;
 498         }
 499
 500         mesh->catta_interfaces = 0;
 501 }