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 #if defined(__APPLE__) || defined(__unix) && !defined(__linux)
  13 #include <net/route.h>
  14 #endif
  15
  16 #include "meshlink_internal.h"
  17 #include "event.h"
  18 #include "discovery.h"
  19 #include "sockaddr.h"
  20 #include "logger.h"
  21 #include "node.h"
  22 #include "connection.h"
  23 #include "xalloc.h"
  24
  25 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
  26 #define MESHLINK_MDNS_NAME_KEY "name"
  27 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
  28
  29 static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
  30         assert(size);
  31
  32         for(size_t i = 0; i < (size - 1); ++i) {
  33                 buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
  34         }
  35
  36         buffer[size - 1] = '\0';
  37 }
  38
  39 static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
  40         (void)server;
  41         (void)group;
  42         meshlink_handle_t *mesh = userdata;
  43
  44         assert(mesh);
  45         assert(mesh->catta_server);
  46         assert(mesh->catta_poll);
  47
  48         /* Called whenever the entry group state changes */
  49         switch(state) {
  50         case CATTA_ENTRY_GROUP_ESTABLISHED:
  51                 /* The entry group has been established successfully */
  52                 logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
  53                 break;
  54
  55         case CATTA_ENTRY_GROUP_COLLISION:
  56                 logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
  57                 // @TODO can we just set a new name and retry?
  58                 break;
  59
  60         case CATTA_ENTRY_GROUP_FAILURE :
  61                 /* Some kind of failure happened while we were registering our services */
  62                 logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  63                 catta_simple_poll_quit(mesh->catta_poll);
  64                 break;
  65
  66         case CATTA_ENTRY_GROUP_UNCOMMITED:
  67         case CATTA_ENTRY_GROUP_REGISTERING:
  68                 break;
  69         }
  70 }
  71
  72
  73 static void discovery_create_services(meshlink_handle_t *mesh) {
  74         char *fingerprint = NULL;
  75         char *txt_name = NULL;
  76         char *txt_fingerprint = NULL;
  77
  78         assert(mesh);
  79         assert(mesh->name);
  80         assert(mesh->myport);
  81         assert(mesh->catta_server);
  82         assert(mesh->catta_poll);
  83         assert(mesh->catta_servicetype);
  84         assert(mesh->self);
  85
  86         logger(mesh, MESHLINK_DEBUG, "Adding service\n");
  87
  88         /* Ifthis is the first time we're called, let's create a new entry group */
  89         if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
  90                 logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
  91                 goto fail;
  92         }
  93
  94         /* Create txt records */
  95         fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
  96         xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
  97         xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
  98
  99         /* Add the service */
 100         int ret = 0;
 101
 102         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) {
 103                 logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
 104                 goto fail;
 105         }
 106
 107         /* Tell the server to register the service */
 108         if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
 109                 logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
 110                 goto fail;
 111         }
 112
 113         goto done;
 114
 115 fail:
 116         catta_simple_poll_quit(mesh->catta_poll);
 117
 118 done:
 119         free(fingerprint);
 120         free(txt_name);
 121         free(txt_fingerprint);
 122 }
 123
 124 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
 125         (void)server;
 126         meshlink_handle_t *mesh = userdata;
 127
 128         assert(mesh);
 129
 130         switch(state) {
 131         case CATTA_SERVER_RUNNING:
 132                 /* The serve has startup successfully and registered its host
 133                  * name on the network, so it's time to create our services */
 134                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 135
 136                 if(!mesh->catta_group) {
 137                         discovery_create_services(mesh);
 138                 }
 139
 140                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 141
 142                 break;
 143
 144         case CATTA_SERVER_COLLISION: {
 145                 /* A host name collision happened. Let's pick a new name for the server */
 146                 char hostname[17];
 147                 generate_rand_string(mesh, hostname, sizeof(hostname));
 148
 149                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 150
 151                 assert(mesh->catta_server);
 152                 assert(mesh->catta_poll);
 153
 154                 int result = catta_server_set_host_name(mesh->catta_server, hostname);
 155
 156                 if(result < 0) {
 157                         catta_simple_poll_quit(mesh->catta_poll);
 158                 }
 159
 160                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 161         }
 162         break;
 163
 164         case CATTA_SERVER_REGISTERING:
 165                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 166
 167                 /* Let's drop our registered services. When the server is back
 168                  * in CATTA_SERVER_RUNNING state we will register them
 169                  * again with the new host name. */
 170                 if(mesh->catta_group) {
 171                         catta_s_entry_group_reset(mesh->catta_group);
 172                         mesh->catta_group = NULL;
 173                 }
 174
 175                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 176
 177                 break;
 178
 179         case CATTA_SERVER_FAILURE:
 180                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 181
 182                 assert(mesh->catta_server);
 183                 assert(mesh->catta_poll);
 184
 185                 /* Terminate on failure */
 186                 catta_simple_poll_quit(mesh->catta_poll);
 187
 188                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 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         assert(mesh);
 208
 209         if(event != CATTA_RESOLVER_FOUND) {
 210                 catta_s_service_resolver_free(resolver);
 211                 return;
 212         }
 213
 214         // retrieve fingerprint
 215         CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
 216         CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 217
 218         if(node_name_li && node_fp_li) {
 219                 char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
 220                 char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 221
 222                 if(node_name[0] == '=' && node_fp[0] == '=') {
 223                         assert(pthread_mutex_lock(&mesh->mutex) == 0);
 224
 225                         node_name += 1;
 226
 227                         meshlink_node_t *node = meshlink_get_node(mesh, node_name);
 228
 229                         if(node) {
 230                                 logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
 231
 232                                 sockaddr_t naddress;
 233                                 memset(&naddress, 0, sizeof(naddress));
 234
 235                                 switch(address->proto) {
 236                                 case CATTA_PROTO_INET: {
 237                                         naddress.in.sin_family = AF_INET;
 238                                         naddress.in.sin_port = htons(port);
 239                                         naddress.in.sin_addr.s_addr = address->data.ipv4.address;
 240                                 }
 241                                 break;
 242
 243                                 case CATTA_PROTO_INET6: {
 244                                         naddress.in6.sin6_family = AF_INET6;
 245                                         naddress.in6.sin6_port = htons(port);
 246                                         memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
 247                                 }
 248                                 break;
 249
 250                                 default:
 251                                         naddress.unknown.family = AF_UNKNOWN;
 252                                         break;
 253                                 }
 254
 255                                 if(naddress.unknown.family != AF_UNKNOWN) {
 256                                         node_t *n = (node_t *)node;
 257                                         connection_t *c = n->connection;
 258
 259                                         n->catta_address = naddress;
 260                                         node_add_recent_address(mesh, n, &naddress);
 261
 262                                         if(c && c->outgoing && !c->status.active) {
 263                                                 c->outgoing->timeout = 0;
 264
 265                                                 if(c->outgoing->ev.cb) {
 266                                                         timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
 267                                                                 0, 0
 268                                                         });
 269                                                 }
 270
 271                                                 c->last_ping_time = -3600;
 272                                         }
 273
 274                                 } else {
 275                                         logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
 276                                 }
 277                         } else {
 278                                 logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
 279                         }
 280
 281                         assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 282                 }
 283         }
 284
 285         catta_s_service_resolver_free(resolver);
 286 }
 287
 288 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) {
 289         (void)browser;
 290         (void)flags;
 291         meshlink_handle_t *mesh = userdata;
 292
 293         /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
 294         switch(event) {
 295         case CATTA_BROWSER_FAILURE:
 296                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 297                 catta_simple_poll_quit(mesh->catta_poll);
 298                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 299                 break;
 300
 301         case CATTA_BROWSER_NEW:
 302                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 303                 catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
 304                 handle_network_change(mesh, ++mesh->catta_interfaces);
 305                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 306                 break;
 307
 308         case CATTA_BROWSER_REMOVE:
 309                 assert(pthread_mutex_lock(&mesh->mutex) == 0);
 310                 handle_network_change(mesh, --mesh->catta_interfaces);
 311                 assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 312                 break;
 313
 314         case CATTA_BROWSER_ALL_FOR_NOW:
 315         case CATTA_BROWSER_CACHE_EXHAUSTED:
 316                 break;
 317         }
 318 }
 319
 320 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
 321         meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
 322
 323         switch(level) {
 324         case CATTA_LOG_ERROR:
 325                 mlevel = MESHLINK_ERROR;
 326                 break;
 327
 328         case CATTA_LOG_WARN:
 329                 mlevel = MESHLINK_WARNING;
 330                 break;
 331
 332         case CATTA_LOG_NOTICE:
 333         case CATTA_LOG_INFO:
 334                 mlevel = MESHLINK_INFO;
 335                 break;
 336
 337         case CATTA_LOG_DEBUG:
 338         default:
 339                 mlevel = MESHLINK_DEBUG;
 340                 break;
 341         }
 342
 343         logger(NULL, mlevel, "%s\n", txt);
 344 }
 345
 346 static void *discovery_loop(void *userdata) {
 347         bool status = false;
 348         meshlink_handle_t *mesh = userdata;
 349         assert(mesh);
 350
 351         assert(pthread_mutex_lock(&mesh->discovery_mutex) == 0);
 352
 353         // handle catta logs
 354         catta_set_log_function(discovery_log_cb);
 355
 356         // create service type string
 357         char appname[strlen(mesh->appname) + 2];
 358         strcpy(appname, mesh->appname);
 359
 360         for(char *p = appname; *p; p++) {
 361                 if(!isalnum(*p) && *p != '_' && *p != '-') {
 362                         *p = '_';
 363                 }
 364         }
 365
 366         if(!appname[1]) {
 367                 appname[1] = '_';
 368                 appname[2] = '\0';
 369         }
 370
 371         size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
 372         mesh->catta_servicetype = malloc(servicetype_strlen);
 373
 374         if(mesh->catta_servicetype == NULL) {
 375                 logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
 376                 goto fail;
 377         }
 378
 379         snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 380
 381         // Allocate discovery loop object
 382         if(!(mesh->catta_poll = catta_simple_poll_new())) {
 383                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
 384                 goto fail;
 385         }
 386
 387         // generate some unique host name (we actually do not care about it)
 388         char hostname[17];
 389         generate_rand_string(mesh, hostname, sizeof(hostname));
 390
 391         // Let's set the host name for this server.
 392         CattaServerConfig config;
 393         catta_server_config_init(&config);
 394         config.host_name = catta_strdup(hostname);
 395         config.publish_workstation = 0;
 396         config.disallow_other_stacks = 0;
 397         config.publish_hinfo = 0;
 398         config.publish_addresses = 1;
 399         config.publish_no_reverse = 1;
 400         config.allow_point_to_point = 1;
 401
 402         /* Allocate a new server */
 403         int error;
 404         mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
 405
 406         /* Free the configuration data */
 407         catta_server_config_free(&config);
 408
 409         /* Check whether creating the server object succeeded */
 410         if(!mesh->catta_server) {
 411                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
 412                 goto fail;
 413         }
 414
 415         // Create the service browser
 416         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))) {
 417                 logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
 418                 goto fail;
 419         }
 420
 421         status = true;
 422
 423 fail:
 424
 425         assert(pthread_cond_broadcast(&mesh->discovery_cond) == 0);
 426         assert(pthread_mutex_unlock(&mesh->discovery_mutex) == 0);
 427
 428         if(status) {
 429                 catta_simple_poll_loop(mesh->catta_poll);
 430         }
 431
 432         if(mesh->catta_browser) {
 433                 catta_s_service_browser_free(mesh->catta_browser);
 434                 mesh->catta_browser = NULL;
 435         }
 436
 437         if(mesh->catta_group) {
 438                 catta_s_entry_group_reset(mesh->catta_group);
 439                 catta_s_entry_group_free(mesh->catta_group);
 440                 mesh->catta_group = NULL;
 441         }
 442
 443         if(mesh->catta_server) {
 444                 catta_server_free(mesh->catta_server);
 445                 mesh->catta_server = NULL;
 446         }
 447
 448         if(mesh->catta_poll) {
 449                 catta_simple_poll_free(mesh->catta_poll);
 450                 mesh->catta_poll = NULL;
 451         }
 452
 453         if(mesh->catta_servicetype) {
 454                 free(mesh->catta_servicetype);
 455                 mesh->catta_servicetype = NULL;
 456         }
 457
 458         return NULL;
 459 }
 460
 461 #ifdef RTM_NEWADDR
 462 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 463         (void)flags;
 464         static time_t prev_update;
 465         meshlink_handle_t *mesh = data;
 466
 467         struct {
 468                 struct rt_msghdr rtm;
 469                 char data[2048];
 470         } msg;
 471
 472         while(true) {
 473                 msg.rtm.rtm_version = 0;
 474                 ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 475
 476                 if(result <= 0) {
 477                         if(result == 0 || errno == EAGAIN || errno == EINTR) {
 478                                 break;
 479                         }
 480
 481                         logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
 482                         io_set(loop, &mesh->pfroute_io, 0);
 483                 }
 484
 485                 if(msg.rtm.rtm_version != RTM_VERSION) {
 486                         logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
 487                         break;
 488                 }
 489
 490                 switch(msg.rtm.rtm_type) {
 491                 case RTM_IFINFO:
 492                 case RTM_NEWADDR:
 493                 case RTM_DELADDR:
 494                         if(loop->now.tv_sec > prev_update + 5) {
 495                                 prev_update = loop->now.tv_sec;
 496                                 handle_network_change(mesh, 1);
 497                         }
 498
 499                         break;
 500
 501                 default:
 502                         break;
 503                 }
 504         }
 505 }
 506 #endif
 507
 508 bool discovery_start(meshlink_handle_t *mesh) {
 509         logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 510
 511         assert(mesh);
 512         assert(!mesh->catta_poll);
 513         assert(!mesh->catta_server);
 514         assert(!mesh->catta_browser);
 515         assert(!mesh->discovery_threadstarted);
 516         assert(!mesh->catta_servicetype);
 517
 518         assert(pthread_mutex_lock(&mesh->discovery_mutex) == 0);
 519
 520         // Start the discovery thread
 521         if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
 522                 assert(pthread_mutex_unlock(&mesh->discovery_mutex) == 0);
 523                 logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
 524                 memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
 525                 return false;
 526         }
 527
 528         assert(pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex) == 0);
 529         assert(pthread_mutex_unlock(&mesh->discovery_mutex) == 0);
 530
 531         mesh->discovery_threadstarted = true;
 532
 533 #ifdef RTM_NEWADDR
 534         int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
 535
 536         if(sock != -1) {
 537                 io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
 538         } else {
 539                 logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
 540         }
 541
 542 #endif
 543
 544         return true;
 545 }
 546
 547 void discovery_stop(meshlink_handle_t *mesh) {
 548         logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
 549
 550         assert(mesh);
 551
 552 #ifdef RTM_NEWADDR
 553
 554         if(mesh->pfroute_io.cb) {
 555                 close(mesh->pfroute_io.fd);
 556                 io_del(&mesh->loop, &mesh->pfroute_io);
 557         }
 558
 559 #endif
 560
 561         // Shut down
 562         if(mesh->catta_poll) {
 563                 catta_simple_poll_quit(mesh->catta_poll);
 564         }
 565
 566         // Wait for the discovery thread to finish
 567         if(mesh->discovery_threadstarted == true) {
 568                 assert(pthread_join(mesh->discovery_thread, NULL) == 0);
 569                 mesh->discovery_threadstarted = false;
 570         }
 571
 572         mesh->catta_interfaces = 0;
 573 }