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(meshlink_handle_t *mesh, char *buffer, size_t size) {
  25         assert(size);
  26
  27         for(size_t i = 0; i < (size - 1); ++i) {
  28                 buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
  29         }
  30
  31         buffer[size - 1] = '\0';
  32 }
  33
  34 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  35         (void)server;
  36         (void)group;
  37         meshlink_handle_t *mesh = userdata;
  38
  39         assert(mesh);
  40         assert(mesh->catta_server);
  41         assert(mesh->catta_poll);
  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                 break;
  64         }
  65 }
  66
  67
  68 static void discovery_create_services(meshlink_handle_t *mesh) {
  69         char *fingerprint = NULL;
  70         char *txt_name = NULL;
  71         char *txt_fingerprint = NULL;
  72
  73         assert(mesh);
  74         assert(mesh->name);
  75         assert(mesh->myport);
  76         assert(mesh->catta_server);
  77         assert(mesh->catta_poll);
  78         assert(mesh->catta_servicetype);
  79         assert(mesh->self);
  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
 119 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 120         (void)server;
 121         meshlink_handle_t *mesh = userdata;
 122
 123         assert(mesh);
 124
 125         switch(state) {
 126         case CATTA_SERVER_RUNNING:
 127                 /* The serve has startup successfully and registered its host
 128                  * name on the network, so it's time to create our services */
 129                 pthread_mutex_lock(&mesh->mutex);
 130
 131                 if(!mesh->catta_group) {
 132                         discovery_create_services(mesh);
 133                 }
 134
 135                 pthread_mutex_unlock(&mesh->mutex);
 136
 137                 break;
 138
 139         case CATTA_SERVER_COLLISION: {
 140                 /* A host name collision happened. Let's pick a new name for the server */
 141                 char hostname[17];
 142                 generate_rand_string(mesh, hostname, sizeof(hostname));
 143
 144                 pthread_mutex_lock(&mesh->mutex);
 145
 146                 assert(mesh->catta_server);
 147                 assert(mesh->catta_poll);
 148
 149                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 150
 151                 if(result < 0) {
 152                         catta_simple_poll_quit(mesh->catta_poll);
 153                 }
 154
 155                 pthread_mutex_unlock(&mesh->mutex);
 156         }
 157         break;
 158
 159         case CATTA_SERVER_REGISTERING:
 160                 pthread_mutex_lock(&mesh->mutex);
 161
 162                 /* Let's drop our registered services. When the server is back
 163                  * in CATTA_SERVER_RUNNING state we will register them
 164                  * again with the new host name. */
 165                 if(mesh->catta_group) {
 166                         catta_s_entry_group_reset(mesh->catta_group);
 167                         mesh->catta_group = NULL;
 168                 }
 169
 170                 pthread_mutex_unlock(&mesh->mutex);
 171
 172                 break;
 173
 174         case CATTA_SERVER_FAILURE:
 175                 pthread_mutex_lock(&mesh->mutex);
 176
 177                 assert(mesh->catta_server);
 178                 assert(mesh->catta_poll);
 179
 180                 /* Terminate on failure */
 181                 catta_simple_poll_quit(mesh->catta_poll);
 182
 183                 pthread_mutex_unlock(&mesh->mutex);
 184                 break;
 185
 186         case CATTA_SERVER_INVALID:
 187                 break;
 188         }
 189 }
 190
 191 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) {
 192         (void)interface_;
 193         (void)protocol;
 194         (void)flags;
 195         (void)name;
 196         (void)type;
 197         (void)domain;
 198         (void)host_name;
 199
 200         meshlink_handle_t *mesh = userdata;
 201
 202         assert(mesh);
 203
 204         if(event != CATTA_RESOLVER_FOUND) {
 205                 catta_s_service_resolver_free(resolver);
 206                 return;
 207         }
 208
 209         // retrieve fingerprint
 210         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 211         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 212
 213         if(node_name_li && node_fp_li) {
 214                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 215                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 216
 217                 if(node_name[0] == '=' && node_fp[0] == '=') {
 218                         pthread_mutex_lock(&mesh->mutex);
 219
 220                         node_name += 1;
 221
 222                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 223
 224                         if(node) {
 225                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 226
 227                                 sockaddr_t naddress;
 228                                 memset(&naddress, 0, sizeof(naddress));
 229
 230                                 switch(address->proto) {
 231                                 case CATTA_PROTO_INET: {
 232                                         naddress.in.sin_family = AF_INET;
 233                                         naddress.in.sin_port = htons(port);
 234                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 235                                 }
 236                                 break;
 237
 238                                 case CATTA_PROTO_INET6: {
 239                                         naddress.in6.sin6_family = AF_INET6;
 240                                         naddress.in6.sin6_port = htons(port);
 241                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 242                                 }
 243                                 break;
 244
 245                                 default:
 246                                         naddress.unknown.family = AF_UNKNOWN;
 247                                         break;
 248                                 }
 249
 250                                 if(naddress.unknown.family != AF_UNKNOWN) {
 251                                         node_t *n = (node_t *)node;
 252                                         connection_t *c = n->connection;
 253
 254                                         node_add_recent_address(mesh, n, &naddress);
 255
 256                                         if(c && c->outgoing && !c->status.active) {
 257                                                 c->outgoing->timeout = 0;
 258
 259                                                 if(c->outgoing->ev.cb) {
 260                                                         timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
 261                                                                 0, 0
 262                                                         });
 263                                                 }
 264
 265                                                 c->last_ping_time = 0;
 266                                         }
 267
 268                                 } else {
 269                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 270                                 }
 271                         } else {
 272                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 273                         }
 274
 275                         pthread_mutex_unlock(&mesh->mutex);
 276                 }
 277         }
 278
 279         catta_s_service_resolver_free(resolver);
 280 }
 281
 282 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) {
 283         (void)browser;
 284         (void)flags;
 285         meshlink_handle_t *mesh = userdata;
 286
 287         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 288         switch(event) {
 289         case CATTA_BROWSER_FAILURE:
 290                 pthread_mutex_lock(&mesh->mutex);
 291                 catta_simple_poll_quit(mesh->catta_poll);
 292                 pthread_mutex_unlock(&mesh->mutex);
 293                 break;
 294
 295         case CATTA_BROWSER_NEW:
 296                 pthread_mutex_lock(&mesh->mutex);
 297                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 298                 handle_network_change(mesh, ++mesh->catta_interfaces);
 299                 pthread_mutex_unlock(&mesh->mutex);
 300                 break;
 301
 302         case CATTA_BROWSER_REMOVE:
 303                 pthread_mutex_lock(&mesh->mutex);
 304                 handle_network_change(mesh, --mesh->catta_interfaces);
 305                 pthread_mutex_unlock(&mesh->mutex);
 306                 break;
 307
 308         case CATTA_BROWSER_ALL_FOR_NOW:
 309         case CATTA_BROWSER_CACHE_EXHAUSTED:
 310                 break;
 311         }
 312 }
 313
 314 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 315         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 316
 317         switch(level) {
 318         case CATTA_LOG_ERROR:
 319                 mlevel = MESHLINK_ERROR;
 320                 break;
 321
 322         case CATTA_LOG_WARN:
 323                 mlevel = MESHLINK_WARNING;
 324                 break;
 325
 326         case CATTA_LOG_NOTICE:
 327         case CATTA_LOG_INFO:
 328                 mlevel = MESHLINK_INFO;
 329                 break;
 330
 331         case CATTA_LOG_DEBUG:
 332         default:
 333                 mlevel = MESHLINK_DEBUG;
 334                 break;
 335         }
 336
 337         logger(NULL, mlevel, "%s\n", txt);
 338 }
 339
 340 static void *discovery_loop(void *userdata) {
 341         bool status = false;
 342         meshlink_handle_t *mesh = userdata;
 343         assert(mesh);
 344
 345         // handle catta logs
 346         catta_set_log_function(discovery_log_cb);
 347
 348         // create service type string
 349         char appname[strlen(mesh->appname) + 2];
 350         strcpy(appname, mesh->appname);
 351
 352         for(char *p = appname; *p; p++) {
 353                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 354                         *p = '_';
 355                 }
 356         }
 357
 358         if(!appname[1]) {
 359                 appname[1] = '_';
 360                 appname[2] = '\0';
 361         }
 362
 363         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 364         mesh->catta_servicetype = malloc(servicetype_strlen);
 365
 366         if(mesh->catta_servicetype == NULL) {
 367                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 368                 goto fail;
 369         }
 370
 371         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 372
 373         // Allocate discovery loop object
 374         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 375                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 376                 goto fail;
 377         }
 378
 379         // generate some unique host name (we actually do not care about it)
 380         char hostname[17];
 381         generate_rand_string(mesh, hostname, sizeof(hostname));
 382
 383         // Let's set the host name for this server.
 384         CattaServerConfig config;
 385         catta_server_config_init(&config);
 386         config.host_name = catta_strdup(hostname);
 387         config.publish_workstation = 0;
 388         config.disallow_other_stacks = 0;
 389         config.publish_hinfo = 0;
 390         config.publish_addresses = 1;
 391         config.publish_no_reverse = 1;
 392
 393         /* Allocate a new server */
 394         int error;
 395         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 396
 397         /* Free the configuration data */
 398         catta_server_config_free(&config);
 399
 400         /* Check whether creating the server object succeeded */
 401         if(!mesh->catta_server) {
 402                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 403                 goto fail;
 404         }
 405
 406         // Create the service browser
 407         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))) {
 408                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 409                 goto fail;
 410         }
 411
 412         status = true;
 413
 414 fail:
 415
 416         pthread_mutex_lock(&mesh->discovery_mutex);
 417         pthread_cond_broadcast(&mesh->discovery_cond);
 418         pthread_mutex_unlock(&mesh->discovery_mutex);
 419
 420         if(status) {
 421                 catta_simple_poll_loop(mesh->catta_poll);
 422         }
 423
 424         if(mesh->catta_browser) {
 425                 catta_s_service_browser_free(mesh->catta_browser);
 426                 mesh->catta_browser = NULL;
 427         }
 428
 429         if(mesh->catta_group) {
 430                 catta_s_entry_group_reset(mesh->catta_group);
 431                 catta_s_entry_group_free(mesh->catta_group);
 432                 mesh->catta_group = NULL;
 433         }
 434
 435         if(mesh->catta_server) {
 436                 catta_server_free(mesh->catta_server);
 437                 mesh->catta_server = NULL;
 438         }
 439
 440         if(mesh->catta_poll) {
 441                 catta_simple_poll_free(mesh->catta_poll);
 442                 mesh->catta_poll = NULL;
 443         }
 444
 445         if(mesh->catta_servicetype) {
 446                 free(mesh->catta_servicetype);
 447                 mesh->catta_servicetype = NULL;
 448         }
 449
 450         return NULL;
 451 }
 452
 453 bool discovery_start(meshlink_handle_t *mesh) {
 454         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 455
 456         assert(mesh);
 457         assert(!mesh->catta_poll);
 458         assert(!mesh->catta_server);
 459         assert(!mesh->catta_browser);
 460         assert(!mesh->discovery_threadstarted);
 461         assert(!mesh->catta_servicetype);
 462
 463         // Start the discovery thread
 464         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 465                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 466                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 467                 return false;
 468         }
 469
 470         pthread_mutex_lock(&mesh->discovery_mutex);
 471         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 472         pthread_mutex_unlock(&mesh->discovery_mutex);
 473
 474         mesh->discovery_threadstarted = true;
 475
 476         return true;
 477 }
 478
 479 void discovery_stop(meshlink_handle_t *mesh) {
 480         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 481
 482         assert(mesh);
 483
 484         // Shut down
 485         if(mesh->catta_poll) {
 486                 catta_simple_poll_quit(mesh->catta_poll);
 487         }
 488
 489         // Wait for the discovery thread to finish
 490         if(mesh->discovery_threadstarted == true) {
 491                 pthread_join(mesh->discovery_thread, NULL);
 492                 mesh->discovery_threadstarted = false;
 493         }
 494
 495         mesh->catta_interfaces = 0;
 496 }