]> git.meshlink.io Git - meshlink/blobdiff - src/discovery.c
Send and receive multicast mDNS packets.
[meshlink] / src / discovery.c
index 5b83862d767c1a48f8d2bd28a3b4349583049601..36d202bde9b192852370e0fc58c53fd9d95ae2b3 100644 (file)
@@ -1,3 +1,5 @@
+#include "system.h"
+
 #include <catta/core.h>
 #include <catta/lookup.h>
 #include <catta/publish.h>
@@ -7,22 +9,52 @@
 #include <catta/alternative.h>
 #include <catta/error.h>
 
+#if defined(__APPLE__) || defined(__unix) && !defined(__linux)
+#include <net/route.h>
+#elif defined(__linux)
+#include <asm/types.h>
+#include <net/if.h>
+#include <linux/if_link.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#endif
+
+#include "mdns.h"
 #include "meshlink_internal.h"
+#include "event.h"
 #include "discovery.h"
 #include "sockaddr.h"
 #include "logger.h"
-
-#include <pthread.h>
-
-#include <netinet/in.h>
+#include "netutl.h"
+#include "node.h"
+#include "connection.h"
+#include "utils.h"
+#include "xalloc.h"
 
 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
 #define MESHLINK_MDNS_NAME_KEY "name"
 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
 
-static void generate_rand_string(char *buffer, size_t size) {
-       for(size_t i = 0; i < (size - 1); ++i)
-               buffer[i] = 'a' + (rand() % ('z' - 'a' + 1));
+static const sockaddr_t mdns_address_ipv4 = {
+       .in.sin_family = AF_INET,
+       .in.sin_addr.s_addr = 0xfb0000e0,
+       .in.sin_port = 0xe914,
+};
+
+static const sockaddr_t mdns_address_ipv6 = {
+       .in6.sin6_family = AF_INET6,
+       .in6.sin6_addr.s6_addr[0x0] = 0xfd,
+       .in6.sin6_addr.s6_addr[0x1] = 0x02,
+       .in6.sin6_addr.s6_addr[0xf] = 0xfb,
+       .in6.sin6_port = 0xe914,
+};
+
+static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
+       assert(size);
+
+       for(size_t i = 0; i < (size - 1); ++i) {
+               buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
+       }
 
        buffer[size - 1] = '\0';
 }
@@ -32,12 +64,9 @@ static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup
        (void)group;
        meshlink_handle_t *mesh = userdata;
 
-       // asserts
-       assert(mesh != NULL);
-       assert(mesh->catta_server != NULL);
-       assert(mesh->catta_poll != NULL);
-
-       pthread_mutex_lock(&(mesh->mesh_mutex));
+       assert(mesh);
+       assert(mesh->catta_server);
+       assert(mesh->catta_poll);
 
        /* Called whenever the entry group state changes */
        switch(state) {
@@ -59,54 +88,41 @@ static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup
 
        case CATTA_ENTRY_GROUP_UNCOMMITED:
        case CATTA_ENTRY_GROUP_REGISTERING:
-               ;
+               break;
        }
-
-       pthread_mutex_unlock(&(mesh->mesh_mutex));
 }
 
 
 static void discovery_create_services(meshlink_handle_t *mesh) {
+       char *fingerprint = NULL;
        char *txt_name = NULL;
+       char *txt_fingerprint = NULL;
 
-       // asserts
-       assert(mesh != NULL);
-       assert(mesh->name != NULL);
-       assert(mesh->myport != NULL);
-       assert(mesh->catta_server != NULL);
-       assert(mesh->catta_poll != NULL);
-       assert(mesh->catta_servicetype != NULL);
-       assert(mesh->self != NULL);
-
-       pthread_mutex_lock(&(mesh->mesh_mutex));
+       assert(mesh);
+       assert(mesh->name);
+       assert(mesh->myport);
+       assert(mesh->catta_server);
+       assert(mesh->catta_poll);
+       assert(mesh->catta_servicetype);
+       assert(mesh->self);
 
        logger(mesh, MESHLINK_DEBUG, "Adding service\n");
 
-       /* Ifthis is the first time we're called, let's create a new entry group */
-       if(!mesh->catta_group) {
-               if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
-                       logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_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) {
-               logger(mesh, MESHLINK_ERROR, "Could not allocate memory for TXT record\n");
+       /* If this is the first time we're called, let's create a new entry group */
+       if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
+               logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
                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));
+       /* Create txt records */
+       fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
+       xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
+       xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
 
        /* Add the service */
        int ret = 0;
-       if((ret = catta_server_add_service(mesh->catta_server, mesh->catta_group, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, 0, meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self), mesh->catta_servicetype, NULL, NULL, atoi(mesh->myport), txt_name, txt_fingerprint, NULL)) < 0) {
+
+       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) {
                logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
                goto fail;
        }
@@ -123,50 +139,61 @@ fail:
        catta_simple_poll_quit(mesh->catta_poll);
 
 done:
-       if(txt_name)
-               free(txt_name);
-
-       pthread_mutex_unlock(&(mesh->mesh_mutex));
+       free(fingerprint);
+       free(txt_name);
+       free(txt_fingerprint);
 }
 
 static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
        (void)server;
        meshlink_handle_t *mesh = userdata;
 
-       // asserts
-       assert(mesh != NULL);
-
-       pthread_mutex_lock(&(mesh->mesh_mutex));
+       assert(mesh);
 
        switch(state) {
-       case CATTA_SERVER_RUNNING: {
+       case CATTA_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->catta_group)
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
+
+               if(!mesh->catta_group) {
                        discovery_create_services(mesh);
-       }
-       break;
+               }
 
-       case CATTA_SERVER_COLLISION: {
-               // asserts
-               assert(mesh->catta_server != NULL);
-               assert(mesh->catta_poll != NULL);
+               pthread_mutex_unlock(&mesh->mutex);
+
+               break;
 
+       case CATTA_SERVER_COLLISION: {
                /* A host name collision happened. Let's pick a new name for the server */
                char hostname[17];
-               generate_rand_string(hostname, sizeof(hostname));
+               generate_rand_string(mesh, hostname, sizeof(hostname));
+
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
+
+               assert(mesh->catta_server);
+               assert(mesh->catta_poll);
 
-               logger(mesh, MESHLINK_WARNING, "Catta host name collision, retrying with '%s'\n", hostname);
                int result = catta_server_set_host_name(mesh->catta_server, hostname);
 
                if(result < 0) {
-                       logger(mesh, MESHLINK_ERROR, "Catta failed to set new host name: %s\n", catta_strerror(result));
                        catta_simple_poll_quit(mesh->catta_poll);
                }
+
+               pthread_mutex_unlock(&mesh->mutex);
        }
        break;
 
-       case CATTA_SERVER_REGISTERING: {
+       case CATTA_SERVER_REGISTERING:
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
+
                /* Let's drop our registered services. When the server is back
                 * in CATTA_SERVER_RUNNING state we will register them
                 * again with the new host name. */
@@ -174,140 +201,122 @@ static void discovery_server_callback(CattaServer *server, CattaServerState stat
                        catta_s_entry_group_reset(mesh->catta_group);
                        mesh->catta_group = NULL;
                }
-       }
-       break;
 
-       case CATTA_SERVER_FAILURE: {
-               // asserts
-               assert(mesh->catta_server != NULL);
-               assert(mesh->catta_poll != NULL);
+               pthread_mutex_unlock(&mesh->mutex);
+
+               break;
+
+       case CATTA_SERVER_FAILURE:
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
+
+               assert(mesh->catta_server);
+               assert(mesh->catta_poll);
 
                /* Terminate on failure */
-               logger(mesh, MESHLINK_ERROR, "Catta server failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
                catta_simple_poll_quit(mesh->catta_poll);
-       }
-       break;
+
+               pthread_mutex_unlock(&mesh->mutex);
+               break;
 
        case CATTA_SERVER_INVALID:
                break;
        }
-
-       pthread_mutex_unlock(&(mesh->mesh_mutex));
 }
 
 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) {
        (void)interface_;
        (void)protocol;
+       (void)flags;
+       (void)name;
+       (void)type;
+       (void)domain;
+       (void)host_name;
+
        meshlink_handle_t *mesh = userdata;
 
-       // asserts
-       assert(resolver != NULL);
-       assert(mesh != NULL);
-       assert(mesh->catta_server != NULL);
+       assert(mesh);
 
-       pthread_mutex_lock(&(mesh->mesh_mutex));
+       if(event != CATTA_RESOLVER_FOUND) {
+               catta_s_service_resolver_free(resolver);
+               return;
+       }
 
-       /* Called whenever a service has been resolved successfully or timed out */
-       switch(event) {
-       case CATTA_RESOLVER_FAILURE: {
-               // asserts
-               assert(name != NULL);
-               assert(type != NULL);
-               assert(domain != NULL);
+       // retrieve fingerprint
+       CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
+       CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
 
-               logger(mesh, MESHLINK_WARNING, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, catta_strerror(catta_server_errno(mesh->catta_server)));
-       }
-       break;
+       if(node_name_li && node_fp_li) {
+               char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
+               char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
 
-       case CATTA_RESOLVER_FOUND: {
-               // asserts
-               assert(name != NULL);
-               assert(type != NULL);
-               assert(domain != NULL);
-               assert(host_name != NULL);
-               assert(address != NULL);
-               assert(txt != NULL);
-
-               char straddr[CATTA_ADDRESS_STR_MAX], *strtxt;
-
-               logger(mesh, MESHLINK_DEBUG, "(Resolver) Service '%s' of type '%s' in domain '%s':\n", name, type, domain);
-
-               catta_address_snprint(straddr, sizeof(straddr), address);
-               strtxt = catta_string_list_to_string(txt);
-               logger(mesh, MESHLINK_DEBUG,
-                      "\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,
-                      catta_string_list_get_service_cookie(txt),
-                      !!(flags & CATTA_LOOKUP_RESULT_LOCAL),
-                      !!(flags & CATTA_LOOKUP_RESULT_WIDE_AREA),
-                      !!(flags & CATTA_LOOKUP_RESULT_MULTICAST),
-                      !!(flags & CATTA_LOOKUP_RESULT_CACHED));
-               catta_free(strtxt);
-
-               // retrieve fingerprint
-               CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
-               CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
-
-               if(node_name_li != NULL && node_fp_li != NULL) {
-                       char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
-                       char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
-
-                       if(node_name[0] == '=' && node_fp[0] == '=') {
-                               node_name += 1;
-                               node_fp += 1;
-
-                               meshlink_node_t *node = meshlink_get_node(mesh, node_name);
-
-                               if(node != NULL) {
-                                       logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
-
-                                       sockaddr_t naddress;
-                                       memset(&naddress, 0, sizeof(naddress));
-
-                                       switch(address->proto) {
-                                       case CATTA_PROTO_INET: {
-                                               naddress.in.sin_family = AF_INET;
-                                               naddress.in.sin_port = htons(port);
-                                               naddress.in.sin_addr.s_addr = address->data.ipv4.address;
-                                       }
-                                       break;
+               if(node_name[0] == '=' && node_fp[0] == '=') {
+                       if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                               abort();
+                       }
 
-                                       case CATTA_PROTO_INET6: {
-                                               naddress.in6.sin6_family = AF_INET6;
-                                               naddress.in6.sin6_port = htons(port);
-                                               memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
-                                       }
+                       node_name += 1;
+
+                       meshlink_node_t *node = meshlink_get_node(mesh, node_name);
+
+                       if(node) {
+                               logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
+
+                               sockaddr_t naddress;
+                               memset(&naddress, 0, sizeof(naddress));
+
+                               switch(address->proto) {
+                               case CATTA_PROTO_INET: {
+                                       naddress.in.sin_family = AF_INET;
+                                       naddress.in.sin_port = htons(port);
+                                       naddress.in.sin_addr.s_addr = address->data.ipv4.address;
+                               }
+                               break;
+
+                               case CATTA_PROTO_INET6: {
+                                       naddress.in6.sin6_family = AF_INET6;
+                                       naddress.in6.sin6_port = htons(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) {
+                                       node_t *n = (node_t *)node;
+                                       connection_t *c = n->connection;
 
-                                       default:
-                                               naddress.unknown.family = AF_UNKNOWN;
-                                               break;
+                                       n->catta_address = naddress;
+                                       node_add_recent_address(mesh, n, &naddress);
+
+                                       if(c && c->outgoing && !c->status.active) {
+                                               c->outgoing->timeout = 0;
+
+                                               if(c->outgoing->ev.cb) {
+                                                       timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
+                                                               0, 0
+                                                       });
+                                               }
+
+                                               c->last_ping_time = -3600;
                                        }
 
-                                       if(naddress.unknown.family != AF_UNKNOWN)
-                                               meshlink_hint_address(mesh, (meshlink_node_t *)node, (struct sockaddr *)&naddress);
-                                       else
-                                               logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
-                               } else
-                                       logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
-                       } else
-                               logger(mesh, MESHLINK_WARNING, "TXT records invalid.\n");
-               } else
-                       logger(mesh, MESHLINK_WARNING, "TXT records missing.\n");
-       }
-       break;
+                               } else {
+                                       logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
+                               }
+                       } else {
+                               logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
+                       }
+
+                       pthread_mutex_unlock(&mesh->mutex);
+               }
        }
 
        catta_s_service_resolver_free(resolver);
-
-       pthread_mutex_unlock(&(mesh->mesh_mutex));
 }
 
 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) {
@@ -315,67 +324,40 @@ static void discovery_browse_callback(CattaSServiceBrowser *browser, CattaIfInde
        (void)flags;
        meshlink_handle_t *mesh = userdata;
 
-       // asserts
-       assert(mesh != NULL);
-       assert(mesh->catta_server != NULL);
-       assert(mesh->catta_poll != NULL);
-
-       pthread_mutex_lock(&(mesh->mesh_mutex));
-
        /* Called whenever a new services becomes available on the LAN or is removed from the LAN */
        switch(event) {
-       case CATTA_BROWSER_FAILURE: {
-               logger(mesh, MESHLINK_ERROR, "(Browser) %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
+       case CATTA_BROWSER_FAILURE:
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
+
                catta_simple_poll_quit(mesh->catta_poll);
-       }
-       break;
+               pthread_mutex_unlock(&mesh->mutex);
+               break;
 
-       case CATTA_BROWSER_NEW: {
-               // asserts
-               assert(name != NULL);
-               assert(type != NULL);
-               assert(domain != NULL);
+       case CATTA_BROWSER_NEW:
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
 
-               logger(mesh, MESHLINK_DEBUG, "(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(!(catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh)))
-                       logger(mesh, MESHLINK_DEBUG, "Failed to resolve service '%s': %s\n", name, catta_strerror(catta_server_errno(mesh->catta_server)));
-       }
-       break;
+               catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
+               handle_network_change(mesh, ++mesh->catta_interfaces);
+               pthread_mutex_unlock(&mesh->mutex);
+               break;
 
-       case CATTA_BROWSER_REMOVE: {
-               // asserts
-               assert(name != NULL);
-               assert(type != NULL);
-               assert(domain != NULL);
+       case CATTA_BROWSER_REMOVE:
+               if(pthread_mutex_lock(&mesh->mutex) != 0) {
+                       abort();
+               }
 
-               logger(mesh, MESHLINK_DEBUG, "(Browser) REMOVE: service '%s' of type '%s' in domain '%s'\n", name, type, domain);
-       }
-       break;
+               handle_network_change(mesh, --mesh->catta_interfaces);
+               pthread_mutex_unlock(&mesh->mutex);
+               break;
 
        case CATTA_BROWSER_ALL_FOR_NOW:
-       case CATTA_BROWSER_CACHE_EXHAUSTED: {
-               logger(mesh, MESHLINK_DEBUG, "(Browser) %s\n", event == CATTA_BROWSER_CACHE_EXHAUSTED ? "CACHE_EXHAUSTED" : "ALL_FOR_NOW");
-       }
-       break;
+       case CATTA_BROWSER_CACHE_EXHAUSTED:
+               break;
        }
-
-       pthread_mutex_unlock(&(mesh->mesh_mutex));
-}
-
-static void *discovery_loop(void *userdata) {
-       meshlink_handle_t *mesh = userdata;
-
-       // asserts
-       assert(mesh != NULL);
-       assert(mesh->catta_poll != NULL);
-
-       catta_simple_poll_loop(mesh->catta_poll);
-
-       return NULL;
 }
 
 static void discovery_log_cb(CattaLogLevel level, const char *txt) {
@@ -404,22 +386,41 @@ static void discovery_log_cb(CattaLogLevel level, const char *txt) {
        logger(NULL, mlevel, "%s\n", txt);
 }
 
-bool discovery_start(meshlink_handle_t *mesh) {
-       logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
+static void *discovery_loop(void *userdata) {
+       bool status = false;
+       meshlink_handle_t *mesh = userdata;
+       assert(mesh);
 
-       // asserts
-       assert(mesh != NULL);
-       assert(mesh->catta_poll == NULL);
-       assert(mesh->catta_server == NULL);
-       assert(mesh->catta_browser == NULL);
-       assert(mesh->discovery_threadstarted == false);
-       assert(mesh->catta_servicetype == NULL);
+       if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
+               abort();
+       }
+
+#if 1
+       // bypass Catta
+       pthread_cond_broadcast(&mesh->discovery_cond);
+       pthread_mutex_unlock(&mesh->discovery_mutex);
+       return NULL;
+#endif
 
        // handle catta logs
        catta_set_log_function(discovery_log_cb);
 
        // create service type string
-       size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(mesh->appname) + 1;
+       char appname[strlen(mesh->appname) + 2];
+       strcpy(appname, mesh->appname);
+
+       for(char *p = appname; *p; p++) {
+               if(!isalnum(*p) && *p != '_' && *p != '-') {
+                       *p = '_';
+               }
+       }
+
+       if(!appname[1]) {
+               appname[1] = '_';
+               appname[2] = '\0';
+       }
+
+       size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
        mesh->catta_servicetype = malloc(servicetype_strlen);
 
        if(mesh->catta_servicetype == NULL) {
@@ -427,7 +428,7 @@ bool discovery_start(meshlink_handle_t *mesh) {
                goto fail;
        }
 
-       snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, mesh->appname);
+       snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
 
        // Allocate discovery loop object
        if(!(mesh->catta_poll = catta_simple_poll_new())) {
@@ -437,7 +438,7 @@ bool discovery_start(meshlink_handle_t *mesh) {
 
        // generate some unique host name (we actually do not care about it)
        char hostname[17];
-       generate_rand_string(hostname, sizeof(hostname));
+       generate_rand_string(mesh, hostname, sizeof(hostname));
 
        // Let's set the host name for this server.
        CattaServerConfig config;
@@ -448,15 +449,23 @@ bool discovery_start(meshlink_handle_t *mesh) {
        config.publish_hinfo = 0;
        config.publish_addresses = 1;
        config.publish_no_reverse = 1;
+       config.allow_point_to_point = 1;
 
        /* Allocate a new server */
        int error;
-       mesh->catta_server = catta_server_new(catta_simple_poll_get(mesh->catta_poll), &config, discovery_server_callback, mesh, &error);
+       const CattaPoll *poller = catta_simple_poll_get(mesh->catta_poll);
+
+       if(!poller) {
+               logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
+               goto fail;
+       }
+
+       mesh->catta_server = catta_server_new(poller, &config, discovery_server_callback, mesh, &error);
 
        /* Free the configuration data */
        catta_server_config_free(&config);
 
-       /* Check wether creating the server object succeeded */
+       /* Check whether creating the server object succeeded */
        if(!mesh->catta_server) {
                logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
                goto fail;
@@ -468,81 +477,719 @@ bool discovery_start(meshlink_handle_t *mesh) {
                goto fail;
        }
 
-       // Start the discovery thread
-       if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
-               logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
-               memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
-               goto fail;
-       }
+       status = true;
 
-       mesh->discovery_threadstarted = true;
+fail:
 
-       return true;
+       pthread_cond_broadcast(&mesh->discovery_cond);
+       pthread_mutex_unlock(&mesh->discovery_mutex);
 
-fail:
-       if(mesh->catta_browser != NULL) {
+       if(status) {
+               catta_simple_poll_loop(mesh->catta_poll);
+       }
+
+       if(mesh->catta_browser) {
                catta_s_service_browser_free(mesh->catta_browser);
                mesh->catta_browser = NULL;
        }
 
-       if(mesh->catta_server != NULL) {
+       if(mesh->catta_group) {
+               catta_s_entry_group_reset(mesh->catta_group);
+               catta_s_entry_group_free(mesh->catta_group);
+               mesh->catta_group = NULL;
+       }
+
+       if(mesh->catta_server) {
                catta_server_free(mesh->catta_server);
                mesh->catta_server = NULL;
        }
 
-       if(mesh->catta_poll != NULL) {
+       if(mesh->catta_poll) {
                catta_simple_poll_free(mesh->catta_poll);
                mesh->catta_poll = NULL;
        }
 
-       if(mesh->catta_servicetype != NULL) {
+       if(mesh->catta_servicetype) {
                free(mesh->catta_servicetype);
                mesh->catta_servicetype = NULL;
        }
 
-       return false;
+       return NULL;
 }
 
-void discovery_stop(meshlink_handle_t *mesh) {
-       logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
+typedef struct discovery_address {
+       int index;
+       bool up;
+       sockaddr_t address;
+} discovery_address_t;
 
-       // asserts
-       assert(mesh != NULL);
+static int iface_compare(const void *va, const void *vb) {
+       const int *a = va;
+       const int *b = vb;
+       return *a - *b;
+}
 
-       // Shut down
-       if(mesh->catta_poll)
-               catta_simple_poll_quit(mesh->catta_poll);
+static int address_compare(const void *va, const void *vb) {
+       const discovery_address_t *a = va;
+       const discovery_address_t *b = vb;
 
-       // Wait for the discovery thread to finish
-       if(mesh->discovery_threadstarted == true) {
-               pthread_join(mesh->discovery_thread, NULL);
-               mesh->discovery_threadstarted = false;
+       if(a->index != b->index) {
+               return a->index - b->index;
        }
 
-       // Clean up resources
-       if(mesh->catta_browser != NULL) {
-               catta_s_service_browser_free(mesh->catta_browser);
-               mesh->catta_browser = NULL;
+       return sockaddrcmp_noport(&a->address, &b->address);
+}
+
+static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
+#ifdef IP_PKTINFO
+       struct iovec iov  = {
+               .iov_base = data,
+               .iov_len = len,
+       };
+
+       struct in_pktinfo pkti = {
+               .ipi_ifindex = index,
+               .ipi_addr = src->in.sin_addr,
+       };
+
+       union {
+               char buf[CMSG_SPACE(sizeof(pkti))];
+               struct cmsghdr align;
+       } u;
+
+       struct msghdr msg = {
+               .msg_name = (struct sockaddr *) &dest->sa,
+               .msg_namelen = SALEN(dest->sa),
+               .msg_iov = &iov,
+               .msg_iovlen = 1,
+               .msg_control = u.buf,
+               .msg_controllen = sizeof(u.buf),
+       };
+
+
+       struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+       cmsg->cmsg_level = IPPROTO_IP;
+       cmsg->cmsg_type = IP_PKTINFO;
+       cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
+       memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
+
+       // Send the packet
+       ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+#else
+       // Send the packet
+       ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
+#endif
+
+       if(result <= 0) {
+               logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
        }
+}
 
-       if(mesh->catta_group) {
-               catta_s_entry_group_reset(mesh->catta_group);
-               catta_s_entry_group_free(mesh->catta_group);
-               mesh->catta_group = NULL;
+static void send_mdns_packet_ipv6(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
+#ifdef IPV6_PKTINFO
+       struct iovec iov  = {
+               .iov_base = data,
+               .iov_len = len,
+       };
+
+       struct in6_pktinfo pkti = {
+               .ipi6_ifindex = index,
+               .ipi6_addr = src->in6.sin6_addr,
+       };
+
+       union {
+               char buf[CMSG_SPACE(sizeof(pkti))];
+               struct cmsghdr align;
+       } u;
+
+       memset(&u, 0, sizeof u);
+
+       struct msghdr msg = {
+               .msg_name = (struct sockaddr *) &dest->sa,
+               .msg_namelen = SALEN(dest->sa),
+               .msg_iov = &iov,
+               .msg_iovlen = 1,
+               .msg_control = u.buf,
+               .msg_controllen = CMSG_LEN(sizeof(pkti)),
+       };
+
+       struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+       cmsg->cmsg_level = IPPROTO_IPV6;
+       cmsg->cmsg_type = IPV6_PKTINFO;
+       cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
+       memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
+
+       // Send the packet
+       ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+#else
+       // Send the packet
+       ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
+#endif
+
+       if(result <= 0) {
+               logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
        }
+}
 
-       if(mesh->catta_server != NULL) {
-               catta_server_free(mesh->catta_server);
-               mesh->catta_server = NULL;
+static void send_mdns_packet(meshlink_handle_t *mesh, const discovery_address_t *addr) {
+       char *host = NULL, *port = NULL;
+       sockaddr2str(&addr->address, &host, &port);
+       fprintf(stderr, "Sending on iface %d %s port %s\n", addr->index, host, port);
+       free(host);
+       free(port);
+
+       // Configure the socket to send the packet to the right interface
+       int fd;
+       uint8_t data[1024];
+       char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
+       const char *keys[] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
+       const char *values[] = {mesh->name, fingerprint};
+       size_t size = prepare_packet(data, sizeof data, fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, values);
+
+       switch(addr->address.sa.sa_family) {
+       case AF_INET:
+               fd = mesh->discovery_sockets[0].fd;
+#ifdef IP_MULTICAST_IF
+               {
+                       struct ip_mreqn mreq = {
+                               .imr_address = addr->address.in.sin_addr,
+                               .imr_ifindex = addr->index,
+                       };
+
+                       if(setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) != 0) {
+                               logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv4 socket");
+                               return;
+                       }
+               }
+
+#endif
+
+               send_mdns_packet_ipv4(mesh, fd, addr->index, &addr->address, &mdns_address_ipv4, data, size);
+               break;
+
+       case AF_INET6:
+               fd = mesh->discovery_sockets[1].fd;
+#ifdef IPV6_MULTICAST_IF
+
+               if(setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &addr->index, sizeof(addr->index)) != 0) {
+                       logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv6 socket");
+                       return;
+               }
+
+#endif
+
+               send_mdns_packet_ipv6(mesh, fd, addr->index, &addr->address, &mdns_address_ipv6, data, size);
+               break;
+
+       default:
+               break;
        }
+}
 
-       if(mesh->catta_poll != NULL) {
-               catta_simple_poll_free(mesh->catta_poll);
-               mesh->catta_poll = NULL;
+static void mdns_io_handler(event_loop_t *loop, void *data, int flags) {
+       (void)flags;
+       meshlink_handle_t *mesh = loop->data;
+       io_t *io = data;
+       uint8_t buf[1024];
+       sockaddr_t sa;
+       socklen_t sl = sizeof(sa);
+
+       ssize_t len = recvfrom(io->fd, buf, sizeof(buf), MSG_DONTWAIT, &sa.sa, &sl);
+
+       if(len == -1) {
+               if(!sockwouldblock(errno)) {
+                       fprintf(stderr, "Error reading from discovery socket: %s\n", strerror(errno));
+                       logger(mesh, MESHLINK_ERROR, "Error reading from mDNS discovery socket: %s", strerror(errno));
+                       io_set(loop, io, 0);
+               }
+
+               return;
        }
 
-       if(mesh->catta_servicetype != NULL) {
-               free(mesh->catta_servicetype);
-               mesh->catta_servicetype = NULL;
+       char *name = NULL;
+       uint16_t port = 0;
+       const char *keys[2] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
+       char *values[2] = {NULL, NULL};
+
+       if(parse_packet(buf, len, &name, mesh->appname, "tcp", &port, 2, keys, values)) {
+               node_t *n = (node_t *)meshlink_get_node(mesh, values[0]);
+
+               if(n) {
+                       logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", n->name);
+
+                       switch(sa.sa.sa_family) {
+                       case AF_INET:
+                               sa.in.sin_port = port;
+                               break;
+
+                       case AF_INET6:
+                               sa.in6.sin6_port = port;
+                               break;
+
+                       default:
+                               logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", n->name);
+                               sa.sa.sa_family = AF_UNKNOWN;
+                               break;
+                       }
+
+                       if(sa.sa.sa_family != AF_UNKNOWN) {
+                               n->catta_address = sa;
+                               node_add_recent_address(mesh, n, &sa);
+
+                               connection_t *c = n->connection;
+
+                               if(c && c->outgoing && !c->status.active) {
+                                       c->outgoing->timeout = 0;
+
+                                       if(c->outgoing->ev.cb) {
+                                               timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
+                                                       0, 0
+                                               });
+                                       }
+
+                                       c->last_ping_time = -3600;
+                               }
+                       }
+               } else {
+                       logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", values[0]);
+               }
+
+               fprintf(stderr, "Got packet from %s port %u\n%s=%s\n%s=%s\n", name, port, keys[0], values[0], keys[1], values[1]);
+       }
+
+       free(name);
+
+       for(int i = 0; i < 2; i++) {
+               free(values[i]);
+       }
+}
+
+static void iface_up(meshlink_handle_t *mesh, int index) {
+       int *p = bsearch(&index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
+
+       if(p) {
+               return;
+       }
+
+       fprintf(stderr, "iface %d up\n", index);
+       mesh->discovery_ifaces = xrealloc(mesh->discovery_ifaces, ++mesh->discovery_iface_count * sizeof(*p));
+       mesh->discovery_ifaces[mesh->discovery_iface_count - 1] = index;
+       qsort(mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
+
+       // Add multicast membership
+       struct ip_mreqn mreq4 = {
+               .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
+               .imr_ifindex = index,
+       };
+       setsockopt(mesh->discovery_sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
+       setsockopt(mesh->discovery_sockets[0].fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq4, sizeof(mreq4));
+
+       struct ipv6_mreq mreq6 = {
+               .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
+               .ipv6mr_interface = index,
+       };
+       setsockopt(mesh->discovery_sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
+       setsockopt(mesh->discovery_sockets[1].fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6));
+
+       // Send an announcement for all addresses associated with this interface
+       for(int i = 0; i < mesh->discovery_address_count; i++) {
+               if(mesh->discovery_addresses[i].index == index) {
+                       send_mdns_packet(mesh, &mesh->discovery_addresses[i]);
+               }
+       }
+
+       handle_network_change(mesh, true);
+}
+
+static void iface_down(meshlink_handle_t *const mesh, int index) {
+       int *p = bsearch(&index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(*p), iface_compare);
+
+       if(!p) {
+               return;
+       }
+
+       // Drop multicast membership
+       struct ip_mreqn mreq4 = {
+               .imr_multiaddr = mdns_address_ipv4.in.sin_addr,
+               .imr_ifindex = index,
+       };
+       setsockopt(mesh->discovery_sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
+
+       struct ipv6_mreq mreq6 = {
+               .ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
+               .ipv6mr_interface = index,
+       };
+       setsockopt(mesh->discovery_sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
+
+       fprintf(stderr, "iface %d down\n", index);
+       memmove(p, p + 1, (mesh->discovery_ifaces + --mesh->discovery_iface_count - p) * sizeof(*p));
+
+       handle_network_change(mesh, mesh->discovery_iface_count);
+}
+
+static void addr_add(meshlink_handle_t *mesh, const discovery_address_t *addr) {
+       discovery_address_t *p = bsearch(addr, mesh->discovery_addresses, mesh->discovery_address_count, sizeof(*p), address_compare);
+
+       if(p) {
+               return;
+       }
+
+       bool up = bsearch(&addr->index, mesh->discovery_ifaces, mesh->discovery_iface_count, sizeof(int), iface_compare);
+       char *host = NULL, *port = NULL;
+       sockaddr2str(&addr->address, &host, &port);
+       fprintf(stderr, "address %d %s port %s up %d\n", addr->index, host, port, up);
+       free(host);
+       free(port);
+
+       mesh->discovery_addresses = xrealloc(mesh->discovery_addresses, ++mesh->discovery_address_count * sizeof(*p));
+       mesh->discovery_addresses[mesh->discovery_address_count - 1] = *addr;
+       mesh->discovery_addresses[mesh->discovery_address_count - 1].up = up;
+
+       if(up) {
+               send_mdns_packet(mesh, &mesh->discovery_addresses[mesh->discovery_address_count - 1]);
+       }
+
+       qsort(mesh->discovery_addresses, mesh->discovery_address_count, sizeof(*p), address_compare);
+}
+
+static void addr_del(meshlink_handle_t *mesh, const discovery_address_t *addr) {
+       discovery_address_t *p = bsearch(addr, mesh->discovery_addresses, mesh->discovery_address_count, sizeof(*p), address_compare);
+
+       if(!p) {
+               return;
+       }
+
+       char *host = NULL, *port = NULL;
+       sockaddr2str(&addr->address, &host, &port);
+       fprintf(stderr, "address %d %s port %s down\n", addr->index, host, port);
+       free(host);
+       free(port);
+
+       memmove(p, p + 1, (mesh->discovery_addresses + --mesh->discovery_address_count - p) * sizeof(*p));
+}
+
+#if defined(__linux)
+static void netlink_getlink(int fd) {
+       static const struct {
+               struct nlmsghdr nlm;
+               struct ifinfomsg ifi;
+       } msg = {
+               .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
+               .nlm.nlmsg_type = RTM_GETLINK,
+               .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+               .nlm.nlmsg_seq = 1,
+               .ifi.ifi_family = AF_UNSPEC,
+       };
+       send(fd, &msg, msg.nlm.nlmsg_len, 0);
+}
+
+static void netlink_getaddr(int fd) {
+       static const struct {
+               struct nlmsghdr nlm;
+               struct ifaddrmsg ifa;
+       } msg = {
+               .nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
+               .nlm.nlmsg_type = RTM_GETADDR,
+               .nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+               .nlm.nlmsg_seq = 2,
+               .ifa.ifa_family = AF_UNSPEC,
+       };
+       send(fd, &msg, msg.nlm.nlmsg_len, 0);
+}
+
+
+static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
+       const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
+
+       if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
+               iface_up(mesh, ifi->ifi_index);
+       } else {
+               iface_down(mesh, ifi->ifi_index);
+       }
+}
+
+static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
+       const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
+       const uint8_t *ptr = (const uint8_t *)(ifa + 1);
+       size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
+
+       while(len >= sizeof(struct rtattr)) {
+               const struct rtattr *rta = (const struct rtattr *)ptr;
+
+               if(rta->rta_len <= 0 || rta->rta_len > len) {
+                       break;
+               }
+
+               if(rta->rta_type == IFA_ADDRESS) {
+                       discovery_address_t addr  = {
+                               .index = ifa->ifa_index,
+                       };
+
+                       if(rta->rta_len == 8) {
+                               addr.address.sa.sa_family = AF_INET;
+                               memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
+                               addr.address.in.sin_port = 5353;
+                       } else if(rta->rta_len == 20) {
+                               addr.address.sa.sa_family = AF_INET6;
+                               memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
+                               addr.address.in6.sin6_port = 5353;
+                               addr.address.in6.sin6_scope_id = ifa->ifa_index;
+                       } else {
+                               addr.address.sa.sa_family = AF_UNKNOWN;
+                       }
+
+                       if(addr.address.sa.sa_family != AF_UNKNOWN) {
+                               if(nlm->nlmsg_type == RTM_NEWADDR) {
+                                       addr_add(mesh, &addr);
+                               } else {
+                                       addr_del(mesh, &addr);
+                               }
+                       }
+               }
+
+               unsigned short rta_len = (rta->rta_len + 3) & ~3;
+               ptr += rta_len;
+               len -= rta_len;
+       }
+}
+
+static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
+       const uint8_t *ptr = data;
+
+       while(len >= sizeof(struct nlmsghdr)) {
+               const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
+
+               if(nlm->nlmsg_len > len) {
+                       break;
+               }
+
+               switch(nlm->nlmsg_type) {
+               case RTM_NEWLINK:
+               case RTM_DELLINK:
+                       netlink_parse_link(mesh, nlm);
+                       break;
+
+               case RTM_NEWADDR:
+               case RTM_DELADDR:
+                       netlink_parse_addr(mesh, nlm);
+               }
+
+               ptr += nlm->nlmsg_len;
+               len -= nlm->nlmsg_len;
        }
 }
+
+static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
+       (void)flags;
+       static time_t prev_update;
+       meshlink_handle_t *mesh = data;
+
+       struct {
+               struct nlmsghdr nlm;
+               char data[16384];
+       } msg;
+
+       while(true) {
+               ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
+
+               if(result <= 0) {
+                       if(result == 0 || errno == EAGAIN || errno == EINTR) {
+                               break;
+                       }
+
+                       logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
+                       io_set(loop, &mesh->pfroute_io, 0);
+               }
+
+               if((size_t)result < sizeof(msg.nlm)) {
+                       logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
+                       break;
+               }
+
+               if(msg.nlm.nlmsg_type == NLMSG_DONE) {
+                       if(msg.nlm.nlmsg_seq == 1) {
+                               // We just got the result of GETLINK, now send GETADDR.
+                               netlink_getaddr(mesh->pfroute_io.fd);
+                       }
+               } else {
+                       netlink_parse(mesh, &msg, result);
+
+                       if(loop->now.tv_sec > prev_update + 5) {
+                               prev_update = loop->now.tv_sec;
+                               handle_network_change(mesh, 1);
+                       }
+               }
+       }
+}
+#elif defined(RTM_NEWADDR)
+static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
+       (void)flags;
+       static time_t prev_update;
+       meshlink_handle_t *mesh = data;
+
+       struct {
+               struct rt_msghdr rtm;
+               char data[2048];
+       } msg;
+
+       while(true) {
+               msg.rtm.rtm_version = 0;
+               ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
+
+               if(result <= 0) {
+                       if(result == 0 || errno == EAGAIN || errno == EINTR) {
+                               break;
+                       }
+
+                       logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
+                       io_set(loop, &mesh->pfroute_io, 0);
+               }
+
+               if(msg.rtm.rtm_version != RTM_VERSION) {
+                       logger(mesh, MESHLINK_ERROR, "Invalid PFROUTE message version\n");
+                       break;
+               }
+
+               switch(msg.rtm.rtm_type) {
+               case RTM_IFINFO:
+               case RTM_NEWADDR:
+               case RTM_DELADDR:
+                       if(loop->now.tv_sec > prev_update + 5) {
+                               prev_update = loop->now.tv_sec;
+                               handle_network_change(mesh, 1);
+                       }
+
+                       break;
+
+               default:
+                       break;
+               }
+       }
+}
+#endif
+
+bool discovery_start(meshlink_handle_t *mesh) {
+       logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
+
+       assert(mesh);
+       assert(!mesh->catta_poll);
+       assert(!mesh->catta_server);
+       assert(!mesh->catta_browser);
+       assert(!mesh->discovery_threadstarted);
+       assert(!mesh->catta_servicetype);
+
+       if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
+               abort();
+       }
+
+       // Start the discovery thread
+       if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
+               pthread_mutex_unlock(&mesh->discovery_mutex);
+               logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
+               memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
+               return false;
+       }
+
+       pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
+       pthread_mutex_unlock(&mesh->discovery_mutex);
+
+       mesh->discovery_threadstarted = true;
+
+       // Set up multicast sockets for mDNS
+       static const int one = 1;
+       static const int ttl = 255;
+
+       int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+       sockaddr_t sa4 = {
+               .in.sin_family = AF_INET,
+               .in.sin_port = ntohs(5353),
+       };
+       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+       bind(fd, &sa4.sa, SALEN(sa4.sa));
+       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one));
+       setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
+       io_add(&mesh->loop, &mesh->discovery_sockets[0], mdns_io_handler, &mesh->discovery_sockets[0], fd, IO_READ);
+
+       sockaddr_t sa6 = {
+               .in6.sin6_family = AF_INET6,
+               .in6.sin6_port = ntohs(5353),
+       };
+       fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+       setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+       bind(fd, &sa6.sa, SALEN(sa6.sa));
+       setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
+       setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
+       io_add(&mesh->loop, &mesh->discovery_sockets[1], mdns_io_handler, &mesh->discovery_sockets[1], fd, IO_READ);
+
+#if defined(__linux)
+       int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+
+       if(sock != -1) {
+               struct sockaddr_nl sa;
+               memset(&sa, 0, sizeof(sa));
+               sa.nl_family = AF_NETLINK;
+               sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
+
+               if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
+                       io_add(&mesh->loop, &mesh->pfroute_io, netlink_io_handler, mesh, sock, IO_READ);
+                       netlink_getlink(sock);
+               } else {
+                       logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
+               }
+       } else {
+               logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
+       }
+
+#elif defined(RTM_NEWADDR)
+       int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
+
+       if(sock != -1) {
+               io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
+       } else {
+               logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
+       }
+
+#endif
+
+       return true;
+}
+
+void discovery_stop(meshlink_handle_t *mesh) {
+       logger(mesh, MESHLINK_DEBUG, "discovery_stop called\n");
+
+       assert(mesh);
+
+       free(mesh->discovery_ifaces);
+       free(mesh->discovery_addresses);
+       mesh->discovery_iface_count = 0;
+       mesh->discovery_address_count = 0;
+
+       if(mesh->pfroute_io.cb) {
+               close(mesh->pfroute_io.fd);
+               io_del(&mesh->loop, &mesh->pfroute_io);
+       }
+
+       for(int i = 0; i < 2; i++) {
+               if(mesh->discovery_sockets[i].cb) {
+                       close(mesh->discovery_sockets[i].fd);
+                       io_del(&mesh->loop, &mesh->discovery_sockets[i]);
+               }
+       }
+
+       // Shut down
+       if(mesh->catta_poll) {
+               catta_simple_poll_quit(mesh->catta_poll);
+       }
+
+       // Wait for the discovery thread to finish
+       if(mesh->discovery_threadstarted == true) {
+               if(pthread_join(mesh->discovery_thread, NULL) != 0) {
+                       abort();
+               }
+
+               mesh->discovery_threadstarted = false;
+       }
+
+       mesh->catta_interfaces = 0;
+}