--- /dev/null
- assert(mesh->avahi_poll != NULL);
- assert(mesh->avahi_server != NULL);
- assert(mesh->avahi_browser != NULL);
- assert(mesh->discovery_threadstarted == true);
- assert(mesh->avahi_servicetype != NULL);
+
+ #include "meshlink_internal.h"
+ #include "discovery.h"
+ #include "sockaddr.h"
+
+ #include <pthread.h>
+
+ #include <avahi-core/core.h>
+ #include <avahi-core/lookup.h>
+ #include <avahi-core/publish.h>
+ #include <avahi-common/simple-watch.h>
+ #include <avahi-common/malloc.h>
+ #include <avahi-common/alternative.h>
+ #include <avahi-common/error.h>
+
+ #include <netinet/in.h>
+
+ #include <uuid/uuid.h>
+
+ #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
+ #define MESHLINK_MDNS_NAME_KEY "name"
+ #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
+
+ static void discovery_entry_group_callback(AvahiServer *server, AvahiSEntryGroup *group, AvahiEntryGroupState state, void *userdata)
+ {
+ meshlink_handle_t *mesh = userdata;
+
+ // asserts
+ assert(mesh != NULL);
+ assert(mesh->avahi_server != NULL);
+ assert(mesh->avahi_poll != NULL);
+
+ /* Called whenever the entry group state changes */
+ switch(state)
+ {
+ case AVAHI_ENTRY_GROUP_ESTABLISHED:
+ /* The entry group has been established successfully */
+ fprintf(stderr, "Service successfully established.\n");
+ break;
+
+ case AVAHI_ENTRY_GROUP_COLLISION:
+ fprintf(stderr, "Service collision\n");
+ // @TODO can we just set a new name and retry?
+ break;
+
+ case AVAHI_ENTRY_GROUP_FAILURE :
+ /* Some kind of failure happened while we were registering our services */
+ fprintf(stderr, "Entry group failure: %s\n", avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ avahi_simple_poll_quit(mesh->avahi_poll);
+ break;
+
+ case AVAHI_ENTRY_GROUP_UNCOMMITED:
+ case AVAHI_ENTRY_GROUP_REGISTERING:
+ ;
+ }
+ }
+
+
+ static void discovery_create_services(meshlink_handle_t *mesh)
+ {
+ char *txt_name = NULL;
+
+ // asserts
+ assert(mesh != NULL);
+ assert(mesh->name != NULL);
+ assert(mesh->myport != NULL);
+ assert(mesh->avahi_server != NULL);
+ assert(mesh->avahi_poll != NULL);
+ assert(mesh->avahi_servicetype != NULL);
+ assert(mesh->self != NULL);
+
+ fprintf(stderr, "Adding service\n");
+
+ /* Ifthis is the first time we're called, let's create a new entry group */
+ if(!mesh->avahi_group)
+ {
+ if(!(mesh->avahi_group = avahi_s_entry_group_new(mesh->avahi_server, discovery_entry_group_callback, mesh)))
+ {
+ fprintf(stderr, "avahi_entry_group_new() failed: %s\n", avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ goto fail;
+ }
+ }
+
+ /* Create txt records */
+ size_t txt_name_len = sizeof(MESHLINK_MDNS_NAME_KEY) + 1 + strlen(mesh->name) + 1;
+ txt_name = malloc(txt_name_len);
+
+ if(txt_name == NULL)
+ {
+ fprintf(stderr, "Could not allocate memory for TXT record\n");
+ goto fail;
+ }
+
+ snprintf(txt_name, txt_name_len, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
+
+ char txt_fingerprint[sizeof(MESHLINK_MDNS_FINGERPRINT_KEY) + 1 + MESHLINK_FINGERPRINTLEN + 1];
+ snprintf(txt_fingerprint, sizeof(txt_fingerprint), "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self));
+
+ /* Add the service */
+ int ret = 0;
+ if((ret = avahi_server_add_service(mesh->avahi_server, mesh->avahi_group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self), mesh->avahi_servicetype, NULL, NULL, atoi(mesh->myport), txt_name, txt_fingerprint, NULL)) < 0)
+ {
+ fprintf(stderr, "Failed to add service: %s\n", avahi_strerror(ret));
+ goto fail;
+ }
+
+ /* Tell the server to register the service */
+ if((ret = avahi_s_entry_group_commit(mesh->avahi_group)) < 0)
+ {
+ fprintf(stderr, "Failed to commit entry_group: %s\n", avahi_strerror(ret));
+ goto fail;
+ }
+
+ goto done;
+
+ fail:
+ avahi_simple_poll_quit(mesh->avahi_poll);
+
+ done:
+ if(txt_name)
+ { free(txt_name); }
+ }
+
+ static void discovery_server_callback(AvahiServer *server, AvahiServerState state, void * userdata)
+ {
+ meshlink_handle_t *mesh = userdata;
+
+ // asserts
+ assert(mesh != NULL);
+
+ switch(state)
+ {
+ case AVAHI_SERVER_RUNNING:
+ {
+ /* The serve has startup successfully and registered its host
+ * name on the network, so it's time to create our services */
+ if(!mesh->avahi_group)
+ {
+ discovery_create_services(mesh);
+ }
+ }
+ break;
+
+ case AVAHI_SERVER_COLLISION:
+ {
+ // asserts
+ assert(mesh->avahi_server != NULL);
+ assert(mesh->avahi_poll != NULL);
+
+ /* A host name collision happened. Let's pick a new name for the server */
+ uuid_t hostname;
+ uuid_generate(hostname);
+
+ char hostnamestr[36+1];
+ uuid_unparse_lower(hostname, hostnamestr);
+
+ fprintf(stderr, "Host name collision, retrying with '%s'\n", hostnamestr);
+ int result = avahi_server_set_host_name(mesh->avahi_server, hostnamestr);
+
+ if(result < 0)
+ {
+ fprintf(stderr, "Failed to set new host name: %s\n", avahi_strerror(result));
+ avahi_simple_poll_quit(mesh->avahi_poll);
+ return;
+ }
+ }
+ break;
+
+ case AVAHI_SERVER_REGISTERING:
+ {
+ /* Let's drop our registered services. When the server is back
+ * in AVAHI_SERVER_RUNNING state we will register them
+ * again with the new host name. */
+ if(mesh->avahi_group)
+ {
+ avahi_s_entry_group_reset(mesh->avahi_group);
+ mesh->avahi_group = NULL;
+ }
+ }
+ break;
+
+ case AVAHI_SERVER_FAILURE:
+ {
+ // asserts
+ assert(mesh->avahi_server != NULL);
+ assert(mesh->avahi_poll != NULL);
+
+ /* Terminate on failure */
+ fprintf(stderr, "Server failure: %s\n", avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ avahi_simple_poll_quit(mesh->avahi_poll);
+ }
+ break;
+
+ case AVAHI_SERVER_INVALID:
+ break;
+ }
+ }
+
+ static void discovery_resolve_callback(AvahiSServiceResolver *resolver, AvahiIfIndex interface, AvahiProtocol protocol, AvahiResolverEvent event, const char *name, const char *type, const char *domain, const char *host_name, const AvahiAddress *address, uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags flags, void* userdata)
+ {
+ meshlink_handle_t *mesh = userdata;
+
+ // asserts
+ assert(resolver != NULL);
+ assert(mesh != NULL);
+ assert(mesh->avahi_server != NULL);
+
+ /* Called whenever a service has been resolved successfully or timed out */
+ switch(event)
+ {
+ case AVAHI_RESOLVER_FAILURE:
+ {
+ // asserts
+ assert(name != NULL);
+ assert(type != NULL);
+ assert(domain != NULL);
+
+ fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ }
+ break;
+
+ case AVAHI_RESOLVER_FOUND:
+ {
+ // asserts
+ assert(name != NULL);
+ assert(type != NULL);
+ assert(domain != NULL);
+ assert(host_name != NULL);
+ assert(address != NULL);
+ assert(txt != NULL);
+
+ char straddr[AVAHI_ADDRESS_STR_MAX], *strtxt;
+
+ fprintf(stderr, "(Resolver) Service '%s' of type '%s' in domain '%s':\n", name, type, domain);
+
+ avahi_address_snprint(straddr, sizeof(straddr), address);
+ strtxt = avahi_string_list_to_string(txt);
+ fprintf(stderr,
+ "\t%s:%u (%s)\n"
+ "\tTXT=%s\n"
+ "\tcookie is %u\n"
+ "\tis_local: %i\n"
+ "\twide_area: %i\n"
+ "\tmulticast: %i\n"
+ "\tcached: %i\n",
+ host_name, port, straddr,
+ strtxt,
+ avahi_string_list_get_service_cookie(txt),
+ !!(flags & AVAHI_LOOKUP_RESULT_LOCAL),
+ !!(flags & AVAHI_LOOKUP_RESULT_WIDE_AREA),
+ !!(flags & AVAHI_LOOKUP_RESULT_MULTICAST),
+ !!(flags & AVAHI_LOOKUP_RESULT_CACHED));
+ avahi_free(strtxt);
+
+ // retrieve fingerprint
+ AvahiStringList *node_name_li = avahi_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
+ AvahiStringList *node_fp_li = avahi_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
+
+ if(node_name_li != NULL && node_fp_li != NULL)
+ {
+ char *node_name = avahi_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY) + 1;
+ char *node_fp = avahi_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY) + 1;
+
+ meshlink_node_t *node = meshlink_get_node(mesh, node_name);
+
+ if(node != NULL)
+ {
+ fprintf(stderr, "Node %s is part of the mesh network.\n", node->name);
+
+ sockaddr_t naddress;
+ memset(&naddress, 0, sizeof(naddress));
+
+ switch(address->proto)
+ {
+ case AVAHI_PROTO_INET:
+ {
+ naddress.in.sin_family = AF_INET;
+ naddress.in.sin_port = port;
+ naddress.in.sin_addr.s_addr = address->data.ipv4.address;
+ }
+ break;
+
+ case AVAHI_PROTO_INET6:
+ {
+ naddress.in6.sin6_family = AF_INET6;
+ naddress.in6.sin6_port = port;
+ memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
+ }
+ break;
+
+ default:
+ naddress.unknown.family = AF_UNKNOWN;
+ break;
+ }
+
+ if(naddress.unknown.family != AF_UNKNOWN)
+ {
+ meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr*)&naddress);
+ }
+ else
+ {
+ fprintf(stderr, "Could not resolve node %s to a known address family type.\n", node->name);
+ }
+ }
+ else
+ {
+ fprintf(stderr, "Node %s is not part of the mesh network.\n", node_name);
+ }
+ }
+ else
+ {
+ fprintf(stderr, "TXT records missing.\n");
+ }
+ }
+ break;
+ }
+
+ avahi_s_service_resolver_free(resolver);
+ }
+
+ static void discovery_browse_callback(AvahiSServiceBrowser *browser, AvahiIfIndex interface, AvahiProtocol protocol, AvahiBrowserEvent event, const char *name, const char *type, const char *domain, AvahiLookupResultFlags flags, void* userdata)
+ {
+ meshlink_handle_t *mesh = userdata;
+
+ // asserts
+ assert(mesh != NULL);
+ assert(mesh->avahi_server != NULL);
+ assert(mesh->avahi_poll != NULL);
+
+ /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
+ switch (event)
+ {
+ case AVAHI_BROWSER_FAILURE:
+ {
+ fprintf(stderr, "(Browser) %s\n", avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ avahi_simple_poll_quit(mesh->avahi_poll);
+ }
+ return;
+
+ case AVAHI_BROWSER_NEW:
+ {
+ // asserts
+ assert(name != NULL);
+ assert(type != NULL);
+ assert(domain != NULL);
+
+ fprintf(stderr, "(Browser) NEW: service '%s' of type '%s' in domain '%s'\n", name, type, domain);
+ /* We ignore the returned resolver object. In the callback
+ function we free it. Ifthe server is terminated before
+ the callback function is called the server will free
+ the resolver for us. */
+ if(!(avahi_s_service_resolver_new(mesh->avahi_server, interface, protocol, name, type, domain, AVAHI_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh)))
+ {
+ fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ }
+ }
+ break;
+
+ case AVAHI_BROWSER_REMOVE:
+ {
+ // asserts
+ assert(name != NULL);
+ assert(type != NULL);
+ assert(domain != NULL);
+
+ fprintf(stderr, "(Browser) REMOVE: service '%s' of type '%s' in domain '%s'\n", name, type, domain);
+ }
+ break;
+
+ case AVAHI_BROWSER_ALL_FOR_NOW:
+ case AVAHI_BROWSER_CACHE_EXHAUSTED:
+ {
+ fprintf(stderr, "(Browser) %s\n", event == AVAHI_BROWSER_CACHE_EXHAUSTED ? "CACHE_EXHAUSTED" : "ALL_FOR_NOW");
+ }
+ break;
+ }
+ }
+
+ static void *discovery_loop(void *userdata)
+ {
+ meshlink_handle_t *mesh = userdata;
+
+ // asserts
+ assert(mesh != NULL);
+ assert(mesh->avahi_poll != NULL);
+
+ avahi_simple_poll_loop(mesh->avahi_poll);
+
+ return NULL;
+ }
+
+ bool discovery_start(meshlink_handle_t *mesh)
+ {
+ // asserts
+ assert(mesh != NULL);
+ assert(mesh->avahi_poll == NULL);
+ assert(mesh->avahi_server == NULL);
+ assert(mesh->avahi_browser == NULL);
+ assert(mesh->discovery_threadstarted == false);
+ assert(mesh->avahi_servicetype == NULL);
+
+ // create service type string
+ size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(mesh->appname) + 1;
+ mesh->avahi_servicetype = malloc(servicetype_strlen);
+
+ if(mesh->avahi_servicetype == NULL)
+ {
+ fprintf(stderr, "Failed to allocate memory for service type string.\n");
+ goto fail;
+ }
+
+ snprintf(mesh->avahi_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, mesh->appname);
+
+ // Allocate discovery loop object
+ if(!(mesh->avahi_poll = avahi_simple_poll_new()))
+ {
+ fprintf(stderr, "Failed to create discovery poll object.\n");
+ goto fail;
+ }
+
+ // generate some unique host name (we actually do not care about it)
+ uuid_t hostname;
+ uuid_generate(hostname);
+
+ char hostnamestr[36+1];
+ uuid_unparse_lower(hostname, hostnamestr);
+
+ // Let's set the host name for this server.
+ AvahiServerConfig config;
+ avahi_server_config_init(&config);
+ config.host_name = avahi_strdup(hostnamestr);
+ config.publish_workstation = 0;
+ config.disallow_other_stacks = 0;
+ config.publish_hinfo = 0;
+ config.publish_addresses = 1;
+ config.publish_no_reverse = 1;
+
+ /* Allocate a new server */
+ int error;
+ mesh->avahi_server = avahi_server_new(avahi_simple_poll_get(mesh->avahi_poll), &config, discovery_server_callback, mesh, &error);
+
+ /* Free the configuration data */
+ avahi_server_config_free(&config);
+
+ /* Check wether creating the server object succeeded */
+ if(!mesh->avahi_server)
+ {
+ fprintf(stderr, "Failed to create discovery server: %s\n", avahi_strerror(error));
+ goto fail;
+ }
+
+ // Create the service browser
+ if(!(mesh->avahi_browser = avahi_s_service_browser_new(mesh->avahi_server, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, mesh->avahi_servicetype, NULL, 0, discovery_browse_callback, mesh)))
+ {
+ fprintf(stderr, "Failed to create discovery service browser: %s\n", avahi_strerror(avahi_server_errno(mesh->avahi_server)));
+ goto fail;
+ }
+
+ // Start the discovery thread
+ if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0)
+ {
+ fprintf(stderr, "Could not start discovery thread: %s\n", strerror(errno));
+ memset(&mesh->discovery_thread, 0, sizeof mesh->discovery_thread);
+ goto fail;
+ }
+
+ mesh->discovery_threadstarted = true;
+
+ return true;
+
+ fail:
+ if(mesh->avahi_browser != NULL)
+ {
+ avahi_s_service_browser_free(mesh->avahi_browser);
+ mesh->avahi_browser = NULL;
+ }
+
+ if(mesh->avahi_server != NULL)
+ {
+ avahi_server_free(mesh->avahi_server);
+ mesh->avahi_server = NULL;
+ }
+
+ if(mesh->avahi_poll != NULL)
+ {
+ avahi_simple_poll_free(mesh->avahi_poll);
+ mesh->avahi_poll = NULL;
+ }
+
+ if(mesh->avahi_servicetype != NULL)
+ {
+ free(mesh->avahi_servicetype);
+ mesh->avahi_servicetype = NULL;
+ }
+
+ return false;
+ }
+
+ void discovery_stop(meshlink_handle_t *mesh)
+ {
+ // asserts
+ assert(mesh != NULL);
- // Shut down
- avahi_simple_poll_quit(mesh->avahi_poll);
+
- pthread_join(mesh->discovery_thread, NULL);
++ // Shut down
++ if(mesh->avahi_poll)
++ {
++ avahi_simple_poll_quit(mesh->avahi_poll);
++ }
+
+ // Wait for the discovery thread to finish
- avahi_s_service_browser_free(mesh->avahi_browser);
- mesh->avahi_browser = NULL;
++ if(mesh->discovery_threadstarted == true)
++ {
++ pthread_join(mesh->discovery_thread, NULL);
++ mesh->discovery_threadstarted = false;
++ }
+
+ // Clean up resources
- avahi_server_free(mesh->avahi_server);
- mesh->avahi_server = NULL;
++ if(mesh->avahi_browser != NULL)
++ {
++ avahi_s_service_browser_free(mesh->avahi_browser);
++ mesh->avahi_browser = NULL;
++ }
+
- avahi_simple_poll_free(mesh->avahi_poll);
- mesh->avahi_poll = NULL;
++ if(mesh->avahi_server != NULL)
++ {
++ avahi_server_free(mesh->avahi_server);
++ mesh->avahi_server = NULL;
++ }
+
- free(mesh->avahi_servicetype);
- mesh->avahi_servicetype = NULL;
++ if(mesh->avahi_poll != NULL)
++ {
++ avahi_simple_poll_free(mesh->avahi_poll);
++ mesh->avahi_poll = NULL;
++ }
+
++ if(mesh->avahi_servicetype != NULL)
++ {
++ free(mesh->avahi_servicetype);
++ mesh->avahi_servicetype = NULL;
++ }
+ }
projects / meshlink / commitdiff