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->mesh_mutex));
 130
 131                 if(!mesh->catta_group) {
 132                         discovery_create_services(mesh);
 133                 }
 134
 135                 pthread_mutex_unlock(&(mesh->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->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->mesh_mutex));
 156         }
 157         break;
 158
 159         case CATTA_SERVER_REGISTERING:
 160                 pthread_mutex_lock(&(mesh->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->mesh_mutex));
 171
 172                 break;
 173
 174         case CATTA_SERVER_FAILURE:
 175                 pthread_mutex_lock(&(mesh->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->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->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                                         meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 252
 253                                         node_t *n = (node_t *)node;
 254
 255                                         if(n->connection && n->connection->outgoing) {
 256                                                 n->connection->outgoing->timeout = 0;
 257
 258                                                 if(n->connection->outgoing->ev.cb) {
 259                                                         timeout_set(&mesh->loop, &n->connection->outgoing->ev, &(struct timeval) {
 260                                                                 0, 0
 261                                                         });
 262                                                 }
 263
 264                                                 n->connection->last_ping_time = 0;
 265                                         }
 266
 267                                 } else {
 268                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 269                                 }
 270                         } else {
 271                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 272                         }
 273
 274                         pthread_mutex_unlock(&(mesh->mesh_mutex));
 275                 }
 276         }
 277
 278         catta_s_service_resolver_free(resolver);
 279 }
 280
 281 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) {
 282         (void)browser;
 283         (void)flags;
 284         meshlink_handle_t *mesh = userdata;
 285
 286         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 287         switch(event) {
 288         case CATTA_BROWSER_FAILURE:
 289                 pthread_mutex_lock(&mesh->mesh_mutex);
 290                 catta_simple_poll_quit(mesh->catta_poll);
 291                 pthread_mutex_unlock(&mesh->mesh_mutex);
 292                 break;
 293
 294         case CATTA_BROWSER_NEW:
 295                 pthread_mutex_lock(&mesh->mesh_mutex);
 296                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 297                 handle_network_change(mesh, ++mesh->catta_interfaces);
 298                 pthread_mutex_unlock(&mesh->mesh_mutex);
 299                 break;
 300
 301         case CATTA_BROWSER_REMOVE:
 302                 pthread_mutex_lock(&mesh->mesh_mutex);
 303                 handle_network_change(mesh, --mesh->catta_interfaces);
 304                 pthread_mutex_unlock(&mesh->mesh_mutex);
 305                 break;
 306
 307         case CATTA_BROWSER_ALL_FOR_NOW:
 308         case CATTA_BROWSER_CACHE_EXHAUSTED:
 309                 break;
 310         }
 311 }
 312
 313 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 314         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 315
 316         switch(level) {
 317         case CATTA_LOG_ERROR:
 318                 mlevel = MESHLINK_ERROR;
 319                 break;
 320
 321         case CATTA_LOG_WARN:
 322                 mlevel = MESHLINK_WARNING;
 323                 break;
 324
 325         case CATTA_LOG_NOTICE:
 326         case CATTA_LOG_INFO:
 327                 mlevel = MESHLINK_INFO;
 328                 break;
 329
 330         case CATTA_LOG_DEBUG:
 331         default:
 332                 mlevel = MESHLINK_DEBUG;
 333                 break;
 334         }
 335
 336         logger(NULL, mlevel, "%s\n", txt);
 337 }
 338
 339 static void *discovery_loop(void *userdata) {
 340         bool status = false;
 341         meshlink_handle_t *mesh = userdata;
 342         assert(mesh);
 343
 344         // handle catta logs
 345         catta_set_log_function(discovery_log_cb);
 346
 347         // create service type string
 348         char appname[strlen(mesh->appname) + 2];
 349         strcpy(appname, mesh->appname);
 350
 351         for(char *p = appname; *p; p++) {
 352                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 353                         *p = '_';
 354                 }
 355         }
 356
 357         if(!appname[1]) {
 358                 appname[1] = '_';
 359                 appname[2] = '\0';
 360         }
 361
 362         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 363         mesh->catta_servicetype = malloc(servicetype_strlen);
 364
 365         if(mesh->catta_servicetype == NULL) {
 366                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 367                 goto fail;
 368         }
 369
 370         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 371
 372         // Allocate discovery loop object
 373         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 374                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 375                 goto fail;
 376         }
 377
 378         // generate some unique host name (we actually do not care about it)
 379         char hostname[17];
 380         generate_rand_string(mesh, hostname, sizeof(hostname));
 381
 382         // Let's set the host name for this server.
 383         CattaServerConfig config;
 384         catta_server_config_init(&config);
 385         config.host_name = catta_strdup(hostname);
 386         config.publish_workstation = 0;
 387         config.disallow_other_stacks = 0;
 388         config.publish_hinfo = 0;
 389         config.publish_addresses = 1;
 390         config.publish_no_reverse = 1;
 391
 392         /* Allocate a new server */
 393         int error;
 394         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 395
 396         /* Free the configuration data */
 397         catta_server_config_free(&config);
 398
 399         /* Check wether creating the server object succeeded */
 400         if(!mesh->catta_server) {
 401                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 402                 goto fail;
 403         }
 404
 405         // Create the service browser
 406         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))) {
 407                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 408                 goto fail;
 409         }
 410
 411         status = true;
 412
 413 fail:
 414
 415         pthread_mutex_lock(&mesh->discovery_mutex);
 416         pthread_cond_broadcast(&mesh->discovery_cond);
 417         pthread_mutex_unlock(&mesh->discovery_mutex);
 418
 419         if(status) {
 420                 catta_simple_poll_loop(mesh->catta_poll);
 421         }
 422
 423         if(mesh->catta_browser) {
 424                 catta_s_service_browser_free(mesh->catta_browser);
 425                 mesh->catta_browser = NULL;
 426         }
 427
 428         if(mesh->catta_group) {
 429                 catta_s_entry_group_reset(mesh->catta_group);
 430                 catta_s_entry_group_free(mesh->catta_group);
 431                 mesh->catta_group = NULL;
 432         }
 433
 434         if(mesh->catta_server) {
 435                 catta_server_free(mesh->catta_server);
 436                 mesh->catta_server = NULL;
 437         }
 438
 439         if(mesh->catta_poll) {
 440                 catta_simple_poll_free(mesh->catta_poll);
 441                 mesh->catta_poll = NULL;
 442         }
 443
 444         if(mesh->catta_servicetype) {
 445                 free(mesh->catta_servicetype);
 446                 mesh->catta_servicetype = NULL;
 447         }
 448
 449         return NULL;
 450 }
 451
 452 bool discovery_start(meshlink_handle_t *mesh) {
 453         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 454
 455         assert(mesh);
 456         assert(!mesh->catta_poll);
 457         assert(!mesh->catta_server);
 458         assert(!mesh->catta_browser);
 459         assert(!mesh->discovery_threadstarted);
 460         assert(!mesh->catta_servicetype);
 461
 462         // Start the discovery thread
 463         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 464                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 465                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 466                 return false;
 467         }
 468
 469         pthread_mutex_lock(&mesh->discovery_mutex);
 470         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 471         pthread_mutex_unlock(&mesh->discovery_mutex);
 472
 473         mesh->discovery_threadstarted = true;
 474
 475         return true;
 476 }
 477
 478 void discovery_stop(meshlink_handle_t *mesh) {
 479         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 480
 481         assert(mesh);
 482
 483         // Shut down
 484         if(mesh->catta_poll) {
 485                 catta_simple_poll_quit(mesh->catta_poll);
 486         }
 487
 488         // Wait for the discovery thread to finish
 489         if(mesh->discovery_threadstarted == true) {
 490                 pthread_join(mesh->discovery_thread, NULL);
 491                 mesh->discovery_threadstarted = false;
 492         }
 493
 494         mesh->catta_interfaces = 0;
 495 }