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         assert(size);
  26
  27         for(size_t i = 0; i < (size - 1); ++i) {
  28                 buffer[i] = 'a' + (rand() % ('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         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         assert(mesh);
 126
 127         switch(state) {
 128         case CATTA_SERVER_RUNNING:
 129                 /* The serve has startup successfully and registered its host
 130                  * name on the network, so it's time to create our services */
 131                 pthread_mutex_lock(&(mesh->mesh_mutex));
 132
 133                 if(!mesh->catta_group) {
 134                         discovery_create_services(mesh);
 135                 }
 136
 137                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 138
 139                 break;
 140
 141         case CATTA_SERVER_COLLISION: {
 142                 /* A host name collision happened. Let's pick a new name for the server */
 143                 char hostname[17];
 144                 generate_rand_string(hostname, sizeof(hostname));
 145
 146                 pthread_mutex_lock(&(mesh->mesh_mutex));
 147
 148                 assert(mesh->catta_server);
 149                 assert(mesh->catta_poll);
 150
 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                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 158         }
 159         break;
 160
 161         case CATTA_SERVER_REGISTERING:
 162                 pthread_mutex_lock(&(mesh->mesh_mutex));
 163
 164                 /* Let's drop our registered services. When the server is back
 165                  * in CATTA_SERVER_RUNNING state we will register them
 166                  * again with the new host name. */
 167                 if(mesh->catta_group) {
 168                         catta_s_entry_group_reset(mesh->catta_group);
 169                         mesh->catta_group = NULL;
 170                 }
 171
 172                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 173
 174                 break;
 175
 176         case CATTA_SERVER_FAILURE:
 177                 pthread_mutex_lock(&(mesh->mesh_mutex));
 178
 179                 assert(mesh->catta_server);
 180                 assert(mesh->catta_poll);
 181
 182                 /* Terminate on failure */
 183                 catta_simple_poll_quit(mesh->catta_poll);
 184
 185                 pthread_mutex_unlock(&(mesh->mesh_mutex));
 186                 break;
 187
 188         case CATTA_SERVER_INVALID:
 189                 break;
 190         }
 191 }
 192
 193 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) {
 194         (void)interface_;
 195         (void)protocol;
 196         (void)flags;
 197         (void)name;
 198         (void)type;
 199         (void)domain;
 200         (void)host_name;
 201
 202         meshlink_handle_t *mesh = userdata;
 203
 204         assert(mesh);
 205
 206         if(event != CATTA_RESOLVER_FOUND) {
 207                 catta_s_service_resolver_free(resolver);
 208                 return;
 209         }
 210
 211         // retrieve fingerprint
 212         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 213         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 214
 215         if(node_name_li && node_fp_li) {
 216                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 217                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 218
 219                 if(node_name[0] == '=' && node_fp[0] == '=') {
 220                         pthread_mutex_lock(&(mesh->mesh_mutex));
 221
 222                         node_name += 1;
 223
 224                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 225
 226                         if(node) {
 227                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 228
 229                                 sockaddr_t naddress;
 230                                 memset(&naddress, 0, sizeof(naddress));
 231
 232                                 switch(address->proto) {
 233                                 case CATTA_PROTO_INET: {
 234                                         naddress.in.sin_family = AF_INET;
 235                                         naddress.in.sin_port = htons(port);
 236                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 237                                 }
 238                                 break;
 239
 240                                 case CATTA_PROTO_INET6: {
 241                                         naddress.in6.sin6_family = AF_INET6;
 242                                         naddress.in6.sin6_port = htons(port);
 243                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 244                                 }
 245                                 break;
 246
 247                                 default:
 248                                         naddress.unknown.family = AF_UNKNOWN;
 249                                         break;
 250                                 }
 251
 252                                 if(naddress.unknown.family != AF_UNKNOWN) {
 253                                         meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
 254
 255                                         node_t *n = (node_t *)node;
 256
 257                                         if(n->connection && n->connection->outgoing) {
 258                                                 n->connection->outgoing->timeout = 0;
 259
 260                                                 if(n->connection->outgoing->ev.cb) {
 261                                                         timeout_set(&mesh->loop, &n->connection->outgoing->ev, &(struct timeval) {
 262                                                                 0, 0
 263                                                         });
 264                                                 }
 265
 266                                                 n->connection->last_ping_time = 0;
 267                                         }
 268
 269                                 } else {
 270                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 271                                 }
 272                         } else {
 273                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 274                         }
 275
 276                         pthread_mutex_unlock(&(mesh->mesh_mutex));
 277                 }
 278         }
 279
 280         catta_s_service_resolver_free(resolver);
 281 }
 282
 283 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) {
 284         (void)browser;
 285         (void)flags;
 286         meshlink_handle_t *mesh = userdata;
 287
 288         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 289         switch(event) {
 290         case CATTA_BROWSER_FAILURE:
 291                 pthread_mutex_lock(&mesh->mesh_mutex);
 292                 catta_simple_poll_quit(mesh->catta_poll);
 293                 pthread_mutex_unlock(&mesh->mesh_mutex);
 294                 break;
 295
 296         case CATTA_BROWSER_NEW:
 297                 pthread_mutex_lock(&mesh->mesh_mutex);
 298                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 299                 handle_network_change(mesh, ++mesh->catta_interfaces);
 300                 pthread_mutex_unlock(&mesh->mesh_mutex);
 301                 break;
 302
 303         case CATTA_BROWSER_REMOVE:
 304                 pthread_mutex_lock(&mesh->mesh_mutex);
 305                 handle_network_change(mesh, --mesh->catta_interfaces);
 306                 pthread_mutex_unlock(&mesh->mesh_mutex);
 307                 break;
 308
 309         case CATTA_BROWSER_ALL_FOR_NOW:
 310         case CATTA_BROWSER_CACHE_EXHAUSTED:
 311                 break;
 312         }
 313 }
 314
 315 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 316         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 317
 318         switch(level) {
 319         case CATTA_LOG_ERROR:
 320                 mlevel = MESHLINK_ERROR;
 321                 break;
 322
 323         case CATTA_LOG_WARN:
 324                 mlevel = MESHLINK_WARNING;
 325                 break;
 326
 327         case CATTA_LOG_NOTICE:
 328         case CATTA_LOG_INFO:
 329                 mlevel = MESHLINK_INFO;
 330                 break;
 331
 332         case CATTA_LOG_DEBUG:
 333         default:
 334                 mlevel = MESHLINK_DEBUG;
 335                 break;
 336         }
 337
 338         logger(NULL, mlevel, "%s\n", txt);
 339 }
 340
 341 static void *discovery_loop(void *userdata) {
 342         bool status = false;
 343         meshlink_handle_t *mesh = userdata;
 344         assert(mesh);
 345
 346         // handle catta logs
 347         catta_set_log_function(discovery_log_cb);
 348
 349         // create service type string
 350         char appname[strlen(mesh->appname) + 2];
 351         strcpy(appname, mesh->appname);
 352
 353         for(char *p = appname; *p; p++) {
 354                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 355                         *p = '_';
 356                 }
 357         }
 358
 359         if(!appname[1]) {
 360                 appname[1] = '_';
 361                 appname[2] = '\0';
 362         }
 363
 364         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 365         mesh->catta_servicetype = malloc(servicetype_strlen);
 366
 367         if(mesh->catta_servicetype == NULL) {
 368                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 369                 goto fail;
 370         }
 371
 372         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 373
 374         // Allocate discovery loop object
 375         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 376                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 377                 goto fail;
 378         }
 379
 380         // generate some unique host name (we actually do not care about it)
 381         char hostname[17];
 382         generate_rand_string(hostname, sizeof(hostname));
 383
 384         // Let's set the host name for this server.
 385         CattaServerConfig config;
 386         catta_server_config_init(&config);
 387         config.host_name = catta_strdup(hostname);
 388         config.publish_workstation = 0;
 389         config.disallow_other_stacks = 0;
 390         config.publish_hinfo = 0;
 391         config.publish_addresses = 1;
 392         config.publish_no_reverse = 1;
 393
 394         /* Allocate a new server */
 395         int error;
 396         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 397
 398         /* Free the configuration data */
 399         catta_server_config_free(&config);
 400
 401         /* Check wether creating the server object succeeded */
 402         if(!mesh->catta_server) {
 403                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 404                 goto fail;
 405         }
 406
 407         // Create the service browser
 408         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))) {
 409                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 410                 goto fail;
 411         }
 412
 413         status = true;
 414
 415 fail:
 416
 417         pthread_mutex_lock(&mesh->discovery_mutex);
 418         pthread_cond_broadcast(&mesh->discovery_cond);
 419         pthread_mutex_unlock(&mesh->discovery_mutex);
 420
 421         if(status) {
 422                 catta_simple_poll_loop(mesh->catta_poll);
 423         }
 424
 425         if(mesh->catta_browser) {
 426                 catta_s_service_browser_free(mesh->catta_browser);
 427                 mesh->catta_browser = NULL;
 428         }
 429
 430         if(mesh->catta_group) {
 431                 catta_s_entry_group_reset(mesh->catta_group);
 432                 catta_s_entry_group_free(mesh->catta_group);
 433                 mesh->catta_group = NULL;
 434         }
 435
 436         if(mesh->catta_server) {
 437                 catta_server_free(mesh->catta_server);
 438                 mesh->catta_server = NULL;
 439         }
 440
 441         if(mesh->catta_poll) {
 442                 catta_simple_poll_free(mesh->catta_poll);
 443                 mesh->catta_poll = NULL;
 444         }
 445
 446         if(mesh->catta_servicetype) {
 447                 free(mesh->catta_servicetype);
 448                 mesh->catta_servicetype = NULL;
 449         }
 450
 451         return NULL;
 452 }
 453
 454 bool discovery_start(meshlink_handle_t *mesh) {
 455         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 456
 457         assert(mesh);
 458         assert(!mesh->catta_poll);
 459         assert(!mesh->catta_server);
 460         assert(!mesh->catta_browser);
 461         assert(!mesh->discovery_threadstarted);
 462         assert(!mesh->catta_servicetype);
 463
 464         // Start the discovery thread
 465         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 466                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 467                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 468                 return false;
 469         }
 470
 471         pthread_mutex_lock(&mesh->discovery_mutex);
 472         pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
 473         pthread_mutex_unlock(&mesh->discovery_mutex);
 474
 475         mesh->discovery_threadstarted = true;
 476
 477         return true;
 478 }
 479
 480 void discovery_stop(meshlink_handle_t *mesh) {
 481         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 482
 483         assert(mesh);
 484
 485         // Shut down
 486         if(mesh->catta_poll) {
 487                 catta_simple_poll_quit(mesh->catta_poll);
 488         }
 489
 490         // Wait for the discovery thread to finish
 491         if(mesh->discovery_threadstarted == true) {
 492                 pthread_join(mesh->discovery_thread, NULL);
 493                 mesh->discovery_threadstarted = false;
 494         }
 495
 496         mesh->catta_interfaces = 0;
 497 }