X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fmeshlink.c;h=a5d8d43121b025cf1c7b5993c93b4f464d31e675;hb=8635449a060aae62af80dad139dc06fbb9a346d9;hp=9aca06779a699e17bc667b233571861f507c3b36;hpb=91169c529883e08d7a0245b709483a22a83245ad;p=meshlink

diff --git a/src/meshlink.c b/src/meshlink.c
index 9aca0677..a5d8d431 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -154,7 +154,7 @@ static int socket_in_netns(int domain, int type, int protocol, int netns) {
 	pthread_t thr;
 
 	if(pthread_create(&thr, NULL, socket_in_netns_thread, &params) == 0) {
-		pthread_join(thr, NULL);
+		assert(pthread_join(thr, NULL) == 0);
 	}
 
 	return params.fd;
@@ -268,6 +268,11 @@ char *meshlink_get_external_address_for_family(meshlink_handle_t *mesh, int fami
 
 		int s = socket_in_netns(aip->ai_family, aip->ai_socktype, aip->ai_protocol, mesh->netns);
 
+#ifdef SO_NOSIGPIPE
+		int nosigpipe = 1;
+		setsockopt(s, SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe, sizeof(nosigpipe));
+#endif
+
 		if(s >= 0) {
 			set_timeout(s, 5000);
 
@@ -1213,7 +1218,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	// Create hash for the new key
 	void *new_config_key;
@@ -1222,7 +1227,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	if(!prf(new_key, new_keylen, "MeshLink configuration key", 26, new_config_key, CHACHA_POLY1305_KEYLEN)) {
 		logger(mesh, MESHLINK_ERROR, "Error creating new configuration key!\n");
 		meshlink_errno = MESHLINK_EINTERNAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1231,7 +1236,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	if(!config_copy(mesh, "current", mesh->config_key, "new", new_config_key)) {
 		logger(mesh, MESHLINK_ERROR, "Could not set up configuration in %s/old: %s\n", mesh->confbase, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1242,7 +1247,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	if(!config_rename(mesh, "current", "old")) {
 		logger(mesh, MESHLINK_ERROR, "Cannot rename %s/current to %s/old\n", mesh->confbase, mesh->confbase);
 		meshlink_errno = MESHLINK_ESTORAGE;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1253,7 +1258,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	if(!config_rename(mesh, "new", "current")) {
 		logger(mesh, MESHLINK_ERROR, "Cannot rename %s/new to %s/current\n", mesh->confbase, mesh->confbase);
 		meshlink_errno = MESHLINK_ESTORAGE;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1262,7 +1267,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	// Cleanup the "old" confbase sub-directory
 
 	if(!config_destroy(mesh->confbase, "old")) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1271,7 +1276,7 @@ bool meshlink_encrypted_key_rotate(meshlink_handle_t *mesh, const void *new_key,
 	free(mesh->config_key);
 	mesh->config_key = new_config_key;
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -1456,11 +1461,17 @@ meshlink_handle_t *meshlink_open_ex(const meshlink_open_params_t *params) {
 		}
 	}
 
-	// initialize mutex
+	// initialize mutexes and conds
 	pthread_mutexattr_t attr;
-	pthread_mutexattr_init(&attr);
-	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
-	pthread_mutex_init(&mesh->mutex, &attr);
+	assert(pthread_mutexattr_init(&attr) == 0);
+	assert(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
+	assert(pthread_mutex_init(&mesh->mutex, &attr) == 0);
+	assert(pthread_cond_init(&mesh->cond, NULL) == 0);
+
+	assert(pthread_mutex_init(&mesh->discovery_mutex, NULL) == 0);
+	assert(pthread_cond_init(&mesh->discovery_cond, NULL) == 0);
+
+	assert(pthread_cond_init(&mesh->adns_cond, NULL) == 0);
 
 	mesh->threadstarted = false;
 	event_loop_init(&mesh->loop);
@@ -1560,11 +1571,11 @@ meshlink_submesh_t *meshlink_submesh_open(meshlink_handle_t  *mesh, const char *
 	}
 
 	//lock mesh->nodes
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	s = (meshlink_submesh_t *)create_submesh(mesh, submesh);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return s;
 }
@@ -1576,12 +1587,12 @@ static void *meshlink_main_loop(void *arg) {
 #ifdef HAVE_SETNS
 
 		if(setns(mesh->netns, CLONE_NEWNET) != 0) {
-			pthread_cond_signal(&mesh->cond);
+			assert(pthread_cond_signal(&mesh->cond) == 0);
 			return NULL;
 		}
 
 #else
-		pthread_cond_signal(&mesh->cond);
+		assert(pthread_cond_signal(&mesh->cond) == 0);
 		return NULL;
 #endif // HAVE_SETNS
 	}
@@ -1594,14 +1605,14 @@ static void *meshlink_main_loop(void *arg) {
 
 #endif
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	logger(mesh, MESHLINK_DEBUG, "Starting main_loop...\n");
-	pthread_cond_broadcast(&mesh->cond);
+	assert(pthread_cond_broadcast(&mesh->cond) == 0);
 	main_loop(mesh);
 	logger(mesh, MESHLINK_DEBUG, "main_loop returned.\n");
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 #if HAVE_CATTA
 
@@ -1623,7 +1634,7 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 
 	logger(mesh, MESHLINK_DEBUG, "meshlink_start called\n");
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	assert(mesh->self);
 	assert(mesh->private_key);
@@ -1632,7 +1643,7 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 
 	if(mesh->threadstarted) {
 		logger(mesh, MESHLINK_DEBUG, "thread was already running\n");
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return true;
 	}
 
@@ -1648,7 +1659,7 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 	if(!mesh->name) {
 		logger(mesh, MESHLINK_DEBUG, "No name given!\n");
 		meshlink_errno = MESHLINK_EINVAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -1661,25 +1672,25 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 
 	// Ensure we have a decent amount of stack space. Musl's default of 80 kB is too small.
 	pthread_attr_t attr;
-	pthread_attr_init(&attr);
-	pthread_attr_setstacksize(&attr, 1024 * 1024);
+	assert(pthread_attr_init(&attr) == 0);
+	assert(pthread_attr_setstacksize(&attr, 1024 * 1024) == 0);
 
 	if(pthread_create(&mesh->thread, &attr, meshlink_main_loop, mesh) != 0) {
 		logger(mesh, MESHLINK_DEBUG, "Could not start thread: %s\n", strerror(errno));
 		memset(&mesh->thread, 0, sizeof(mesh)->thread);
 		meshlink_errno = MESHLINK_EINTERNAL;
 		event_loop_stop(&mesh->loop);
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_cond_wait(&mesh->cond, &mesh->mutex);
+	assert(pthread_cond_wait(&mesh->cond, &mesh->mutex) == 0);
 	mesh->threadstarted = true;
 
 	// Ensure we are considered reachable
 	graph(mesh);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return true;
 }
 
@@ -1689,7 +1700,7 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	logger(mesh, MESHLINK_DEBUG, "meshlink_stop called\n");
 
 	// Shut down the main thread
@@ -1712,9 +1723,9 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 
 	if(mesh->threadstarted) {
 		// Wait for the main thread to finish
-		pthread_mutex_unlock(&mesh->mutex);
-		pthread_join(mesh->thread, NULL);
-		pthread_mutex_lock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
+		assert(pthread_join(mesh->thread, NULL) == 0);
+		assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 		mesh->threadstarted = false;
 	}
@@ -1746,7 +1757,7 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 		}
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_close(meshlink_handle_t *mesh) {
@@ -1759,7 +1770,7 @@ void meshlink_close(meshlink_handle_t *mesh) {
 	meshlink_stop(mesh);
 
 	// lock is not released after this
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	// Close and free all resources used.
 
@@ -1803,8 +1814,8 @@ void meshlink_close(meshlink_handle_t *mesh) {
 
 	main_config_unlock(mesh);
 
-	pthread_mutex_unlock(&mesh->mutex);
-	pthread_mutex_destroy(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
+	assert(pthread_mutex_destroy(&mesh->mutex) == 0);
 
 	memset(mesh, 0, sizeof(*mesh));
 
@@ -1880,9 +1891,9 @@ void meshlink_set_receive_cb(meshlink_handle_t *mesh, meshlink_receive_cb_t cb)
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->receive_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_connection_try_cb(meshlink_handle_t *mesh, meshlink_connection_try_cb_t cb) {
@@ -1891,9 +1902,9 @@ void meshlink_set_connection_try_cb(meshlink_handle_t *mesh, meshlink_connection
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->connection_try_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_cb_t cb) {
@@ -1902,9 +1913,9 @@ void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_c
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->node_status_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_node_pmtu_cb(meshlink_handle_t *mesh, meshlink_node_pmtu_cb_t cb) {
@@ -1913,9 +1924,9 @@ void meshlink_set_node_pmtu_cb(meshlink_handle_t *mesh, meshlink_node_pmtu_cb_t
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->node_pmtu_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_node_duplicate_cb(meshlink_handle_t *mesh, meshlink_node_duplicate_cb_t cb) {
@@ -1924,17 +1935,17 @@ void meshlink_set_node_duplicate_cb(meshlink_handle_t *mesh, meshlink_node_dupli
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->node_duplicate_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t level, meshlink_log_cb_t cb) {
 	if(mesh) {
-		pthread_mutex_lock(&mesh->mutex);
+		assert(pthread_mutex_lock(&mesh->mutex) == 0);
 		mesh->log_cb = cb;
 		mesh->log_level = cb ? level : 0;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	} else {
 		global_log_cb = cb;
 		global_log_level = cb ? level : 0;
@@ -1947,9 +1958,9 @@ void meshlink_set_error_cb(struct meshlink_handle *mesh, meshlink_error_cb_t cb)
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->error_cb = cb;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 static bool prepare_packet(meshlink_handle_t *mesh, meshlink_node_t *destination, const void *data, size_t len, vpn_packet_t *packet) {
@@ -2067,19 +2078,19 @@ ssize_t meshlink_get_pmtu(meshlink_handle_t *mesh, meshlink_node_t *destination)
 		return -1;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = (node_t *)destination;
 
 	if(!n->status.reachable) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return 0;
 
 	} else if(n->mtuprobes > 30 && n->minmtu) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return n->minmtu;
 	} else {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return MTU;
 	}
 }
@@ -2090,13 +2101,13 @@ char *meshlink_get_fingerprint(meshlink_handle_t *mesh, meshlink_node_t *node) {
 		return NULL;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = (node_t *)node;
 
 	if(!node_read_public_key(mesh, n) || !n->ecdsa) {
 		meshlink_errno = MESHLINK_EINTERNAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
@@ -2106,7 +2117,7 @@ char *meshlink_get_fingerprint(meshlink_handle_t *mesh, meshlink_node_t *node) {
 		meshlink_errno = MESHLINK_EINTERNAL;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return fingerprint;
 }
 
@@ -2127,9 +2138,9 @@ meshlink_node_t *meshlink_get_node(meshlink_handle_t *mesh, const char *name) {
 
 	node_t *n = NULL;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	n = lookup_node(mesh, (char *)name); // TODO: make lookup_node() use const
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	if(!n) {
 		meshlink_errno = MESHLINK_ENOENT;
@@ -2146,9 +2157,9 @@ meshlink_submesh_t *meshlink_get_submesh(meshlink_handle_t *mesh, const char *na
 
 	meshlink_submesh_t *submesh = NULL;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	submesh = (meshlink_submesh_t *)lookup_submesh(mesh, name);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	if(!submesh) {
 		meshlink_errno = MESHLINK_ENOENT;
@@ -2166,7 +2177,7 @@ meshlink_node_t **meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_
 	meshlink_node_t **result;
 
 	//lock mesh->nodes
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	*nmemb = mesh->nodes->count;
 	result = realloc(nodes, *nmemb * sizeof(*nodes));
@@ -2183,7 +2194,7 @@ meshlink_node_t **meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_
 		meshlink_errno = MESHLINK_ENOMEM;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return result;
 }
@@ -2191,7 +2202,7 @@ meshlink_node_t **meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_
 static meshlink_node_t **meshlink_get_all_nodes_by_condition(meshlink_handle_t *mesh, const void *condition, meshlink_node_t **nodes, size_t *nmemb, search_node_by_condition_t search_node) {
 	meshlink_node_t **result;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	*nmemb = 0;
 
@@ -2203,7 +2214,7 @@ static meshlink_node_t **meshlink_get_all_nodes_by_condition(meshlink_handle_t *
 
 	if(*nmemb == 0) {
 		free(nodes);
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2223,7 +2234,7 @@ static meshlink_node_t **meshlink_get_all_nodes_by_condition(meshlink_handle_t *
 		meshlink_errno = MESHLINK_ENOMEM;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return result;
 }
@@ -2308,11 +2319,11 @@ dev_class_t meshlink_get_node_dev_class(meshlink_handle_t *mesh, meshlink_node_t
 
 	dev_class_t devclass;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	devclass = ((node_t *)node)->devclass;
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return devclass;
 }
@@ -2341,7 +2352,7 @@ bool meshlink_get_node_reachability(struct meshlink_handle *mesh, struct meshlin
 	node_t *n = (node_t *)node;
 	bool reachable;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	reachable = n->status.reachable && !n->status.blacklisted;
 
 	if(last_reachable) {
@@ -2352,7 +2363,7 @@ bool meshlink_get_node_reachability(struct meshlink_handle *mesh, struct meshlin
 		*last_unreachable = n->last_unreachable;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return reachable;
 }
@@ -2368,16 +2379,16 @@ bool meshlink_sign(meshlink_handle_t *mesh, const void *data, size_t len, void *
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(!ecdsa_sign(mesh->private_key, data, len, signature)) {
 		meshlink_errno = MESHLINK_EINTERNAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
 	*siglen = MESHLINK_SIGLEN;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return true;
 }
 
@@ -2392,7 +2403,7 @@ bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const voi
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	bool rval = false;
 
@@ -2405,12 +2416,12 @@ bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const voi
 		rval = ecdsa_verify(((struct node_t *)source)->ecdsa, data, len, signature);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return rval;
 }
 
 static bool refresh_invitation_key(meshlink_handle_t *mesh) {
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	size_t count = invitation_purge_old(mesh, time(NULL) - mesh->invitation_timeout);
 
@@ -2418,7 +2429,7 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 		// TODO: Update invitation key if necessary?
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return mesh->invitation_key;
 }
@@ -2456,18 +2467,18 @@ bool meshlink_set_canonical_address(meshlink_handle_t *mesh, meshlink_node_t *no
 		canonical_address = xstrdup(address);
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = (node_t *)node;
 	free(n->canonical_address);
 	n->canonical_address = canonical_address;
 
 	if(!node_write_config(mesh, n)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return config_sync(mesh, "current");
 }
@@ -2498,14 +2509,14 @@ bool meshlink_add_invitation_address(struct meshlink_handle *mesh, const char *a
 		combo = xstrdup(address);
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(!mesh->invitation_addresses) {
 		mesh->invitation_addresses = list_alloc((list_action_t)free);
 	}
 
 	list_insert_tail(mesh->invitation_addresses, combo);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -2516,14 +2527,14 @@ void meshlink_clear_invitation_addresses(struct meshlink_handle *mesh) {
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(mesh->invitation_addresses) {
 		list_delete_list(mesh->invitation_addresses);
 		mesh->invitation_addresses = NULL;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 bool meshlink_add_address(meshlink_handle_t *mesh, const char *address) {
@@ -2561,9 +2572,9 @@ int meshlink_get_port(meshlink_handle_t *mesh) {
 
 	int port;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	port = atoi(mesh->myport);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return port;
 }
@@ -2587,7 +2598,7 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
 
 	bool rval = false;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(mesh->threadstarted) {
 		meshlink_errno = MESHLINK_EINVAL;
@@ -2628,7 +2639,7 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
 	rval = config_sync(mesh, "current");
 
 done:
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return rval && meshlink_get_port(mesh) == port;
 }
@@ -2657,13 +2668,13 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 		s = (meshlink_submesh_t *)mesh->self->submesh;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	// Check validity of the new node's name
 	if(!check_id(name)) {
 		logger(mesh, MESHLINK_ERROR, "Invalid name for node.\n");
 		meshlink_errno = MESHLINK_EINVAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2671,7 +2682,7 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	if(config_exists(mesh, "current", name)) {
 		logger(mesh, MESHLINK_ERROR, "A host config file for %s already exists!\n", name);
 		meshlink_errno = MESHLINK_EEXIST;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2679,7 +2690,7 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	if(lookup_node(mesh, name)) {
 		logger(mesh, MESHLINK_ERROR, "A node with name %s is already known!\n", name);
 		meshlink_errno = MESHLINK_EEXIST;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2689,13 +2700,13 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	if(!address) {
 		logger(mesh, MESHLINK_ERROR, "No Address known for ourselves!\n");
 		meshlink_errno = MESHLINK_ERESOLV;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
 	if(!refresh_invitation_key(mesh)) {
 		meshlink_errno = MESHLINK_EINTERNAL;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2703,7 +2714,7 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	if(mesh->self->status.dirty) {
 		if(!node_write_config(mesh, mesh->self)) {
 			logger(mesh, MESHLINK_ERROR, "Could not write our own host config file!\n");
-			pthread_mutex_unlock(&mesh->mutex);
+			assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 			return NULL;
 		}
 	}
@@ -2765,7 +2776,7 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	if(!invitation_write(mesh, "current", cookiehash, &config, mesh->config_key)) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create invitation file %s: %s\n", cookiehash, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -2774,7 +2785,7 @@ char *meshlink_invite_ex(meshlink_handle_t *mesh, meshlink_submesh_t *submesh, c
 	xasprintf(&url, "%s/%s%s", address, hash, cookie);
 	free(address);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return url;
 }
 
@@ -2799,7 +2810,7 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	//TODO: think of a better name for this variable, or of a different way to tokenize the invitation URL.
 	char copy[strlen(invitation) + 1];
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	//Before doing meshlink_join make sure we are not connected to another mesh
 	if(mesh->threadstarted) {
@@ -2899,6 +2910,11 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 					continue;
 				}
 
+#ifdef SO_NOSIGPIPE
+				int nosigpipe = 1;
+				setsockopt(state.sock, SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe, sizeof(nosigpipe));
+#endif
+
 				set_timeout(state.sock, 5000);
 
 				if(connect(state.sock, aip->ai_addr, aip->ai_addrlen)) {
@@ -3017,7 +3033,7 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	ecdsa_free(key);
 	closesocket(state.sock);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return true;
 
 invalid:
@@ -3032,7 +3048,7 @@ exit:
 		closesocket(state.sock);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	return false;
 }
 
@@ -3050,7 +3066,7 @@ char *meshlink_export(meshlink_handle_t *mesh) {
 	packmsg_add_str(&out, mesh->name);
 	packmsg_add_str(&out, CORE_MESH);
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	packmsg_add_int32(&out, mesh->self->devclass);
 	packmsg_add_bool(&out, mesh->self->status.blacklisted);
@@ -3084,7 +3100,7 @@ char *meshlink_export(meshlink_handle_t *mesh) {
 	packmsg_add_int64(&out, 0);
 	packmsg_add_int64(&out, 0);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	if(!packmsg_output_ok(&out)) {
 		logger(mesh, MESHLINK_DEBUG, "Error creating export data\n");
@@ -3138,7 +3154,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	while(count--) {
 		const void *data2;
@@ -3194,7 +3210,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 		node_add(mesh, n);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	free(buf);
 
@@ -3262,14 +3278,14 @@ bool meshlink_blacklist(meshlink_handle_t *mesh, meshlink_node_t *node) {
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(!blacklist(mesh, (node_t *)node)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	logger(mesh, MESHLINK_DEBUG, "Blacklisted %s.\n", node->name);
 	return true;
@@ -3281,7 +3297,7 @@ bool meshlink_blacklist_by_name(meshlink_handle_t *mesh, const char *name) {
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = lookup_node(mesh, (char *)name);
 
@@ -3292,11 +3308,11 @@ bool meshlink_blacklist_by_name(meshlink_handle_t *mesh, const char *name) {
 	}
 
 	if(!blacklist(mesh, (node_t *)n)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	logger(mesh, MESHLINK_DEBUG, "Blacklisted %s.\n", name);
 	return true;
@@ -3330,14 +3346,14 @@ bool meshlink_whitelist(meshlink_handle_t *mesh, meshlink_node_t *node) {
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(!whitelist(mesh, (node_t *)node)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	logger(mesh, MESHLINK_DEBUG, "Whitelisted %s.\n", node->name);
 	return true;
@@ -3349,7 +3365,7 @@ bool meshlink_whitelist_by_name(meshlink_handle_t *mesh, const char *name) {
 		return false;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = lookup_node(mesh, (char *)name);
 
@@ -3360,11 +3376,11 @@ bool meshlink_whitelist_by_name(meshlink_handle_t *mesh, const char *name) {
 	}
 
 	if(!whitelist(mesh, (node_t *)n)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	logger(mesh, MESHLINK_DEBUG, "Whitelisted %s.\n", name);
 	return true;
@@ -3382,18 +3398,18 @@ bool meshlink_forget_node(meshlink_handle_t *mesh, meshlink_node_t *node) {
 
 	node_t *n = (node_t *)node;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Check that the node is not reachable */
 	if(n->status.reachable || n->connection) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		logger(mesh, MESHLINK_WARNING, "Could not forget %s: still reachable", n->name);
 		return false;
 	}
 
 	/* Check that we don't have any active UTCP connections */
 	if(n->utcp && utcp_is_active(n->utcp)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		logger(mesh, MESHLINK_WARNING, "Could not forget %s: active UTCP connections", n->name);
 		return false;
 	}
@@ -3401,7 +3417,7 @@ bool meshlink_forget_node(meshlink_handle_t *mesh, meshlink_node_t *node) {
 	/* Check that we have no active connections to this node */
 	for list_each(connection_t, c, mesh->connections) {
 		if(c->node == n) {
-			pthread_mutex_unlock(&mesh->mutex);
+			assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 			logger(mesh, MESHLINK_WARNING, "Could not forget %s: active connection", n->name);
 			return false;
 		}
@@ -3418,14 +3434,14 @@ bool meshlink_forget_node(meshlink_handle_t *mesh, meshlink_node_t *node) {
 
 	/* Delete the config file for this node */
 	if(!config_delete(mesh, "current", n->name)) {
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return false;
 	}
 
 	/* Delete the node struct and any remaining edges referencing this node */
 	node_del(mesh, n);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return config_sync(mesh, "current");
 }
@@ -3439,7 +3455,7 @@ void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node, const
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = (node_t *)node;
 
@@ -3449,7 +3465,7 @@ void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node, const
 		}
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 	// @TODO do we want to fire off a connection attempt right away?
 }
 
@@ -3753,10 +3769,10 @@ void meshlink_set_channel_poll_cb(meshlink_handle_t *mesh, meshlink_channel_t *c
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	channel->poll_cb = cb;
 	utcp_set_poll_cb(channel->c, (cb || channel->aio_send) ? channel_poll : NULL);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_accept_cb_t cb) {
@@ -3765,7 +3781,7 @@ void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_ac
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->channel_accept_cb = cb;
 	mesh->receive_cb = channel_receive;
 
@@ -3777,7 +3793,7 @@ void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_ac
 		}
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_channel_sndbuf(meshlink_handle_t *mesh, meshlink_channel_t *channel, size_t size) {
@@ -3788,9 +3804,9 @@ void meshlink_set_channel_sndbuf(meshlink_handle_t *mesh, meshlink_channel_t *ch
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	utcp_set_sndbuf(channel->c, size);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_channel_rcvbuf(meshlink_handle_t *mesh, meshlink_channel_t *channel, size_t size) {
@@ -3801,9 +3817,9 @@ void meshlink_set_channel_rcvbuf(meshlink_handle_t *mesh, meshlink_channel_t *ch
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	utcp_set_rcvbuf(channel->c, size);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_node_t *node, uint16_t port, meshlink_channel_receive_cb_t cb, const void *data, size_t len, uint32_t flags) {
@@ -3816,7 +3832,7 @@ meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_n
 		return NULL;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	node_t *n = (node_t *)node;
 
@@ -3828,7 +3844,7 @@ meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_n
 
 		if(!n->utcp) {
 			meshlink_errno = errno == ENOMEM ? MESHLINK_ENOMEM : MESHLINK_EINTERNAL;
-			pthread_mutex_unlock(&mesh->mutex);
+			assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 			return NULL;
 		}
 	}
@@ -3836,7 +3852,7 @@ meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_n
 	if(n->status.blacklisted) {
 		logger(mesh, MESHLINK_ERROR, "Cannot open a channel with blacklisted node\n");
 		meshlink_errno = MESHLINK_EBLACKLISTED;
-		pthread_mutex_unlock(&mesh->mutex);
+		assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 		return NULL;
 	}
 
@@ -3850,7 +3866,7 @@ meshlink_channel_t *meshlink_channel_open_ex(meshlink_handle_t *mesh, meshlink_n
 
 	channel->c = utcp_connect_ex(n->utcp, port, channel_recv, channel, flags);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	if(!channel->c) {
 		meshlink_errno = errno == ENOMEM ? MESHLINK_ENOMEM : MESHLINK_EINTERNAL;
@@ -3871,9 +3887,9 @@ void meshlink_channel_shutdown(meshlink_handle_t *mesh, meshlink_channel_t *chan
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	utcp_shutdown(channel->c, direction);
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_channel_close(meshlink_handle_t *mesh, meshlink_channel_t *channel) {
@@ -3882,7 +3898,7 @@ void meshlink_channel_close(meshlink_handle_t *mesh, meshlink_channel_t *channel
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(channel->c) {
 		utcp_close(channel->c);
@@ -3897,7 +3913,7 @@ void meshlink_channel_close(meshlink_handle_t *mesh, meshlink_channel_t *channel
 		free(channel);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *channel, const void *data, size_t len) {
@@ -3922,7 +3938,7 @@ ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *chann
 
 	ssize_t retval;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Disallow direct calls to utcp_send() while we still have AIO active. */
 	if(channel->aio_send) {
@@ -3931,7 +3947,7 @@ ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *chann
 		retval = utcp_send(channel->c, data, len);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	if(retval < 0) {
 		meshlink_errno = MESHLINK_ENETWORK;
@@ -3957,7 +3973,7 @@ bool meshlink_channel_aio_send(meshlink_handle_t *mesh, meshlink_channel_t *chan
 	aio->cb.buffer = cb;
 	aio->priv = priv;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Append the AIO buffer descriptor to the end of the chain */
 	meshlink_aio_buffer_t **p = &channel->aio_send;
@@ -3976,7 +3992,7 @@ bool meshlink_channel_aio_send(meshlink_handle_t *mesh, meshlink_channel_t *chan
 		channel_poll(channel->c, todo);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -3998,7 +4014,7 @@ bool meshlink_channel_aio_fd_send(meshlink_handle_t *mesh, meshlink_channel_t *c
 	aio->cb.fd = cb;
 	aio->priv = priv;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Append the AIO buffer descriptor to the end of the chain */
 	meshlink_aio_buffer_t **p = &channel->aio_send;
@@ -4017,7 +4033,7 @@ bool meshlink_channel_aio_fd_send(meshlink_handle_t *mesh, meshlink_channel_t *c
 		channel_poll(channel->c, left);
 	}
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -4039,7 +4055,7 @@ bool meshlink_channel_aio_receive(meshlink_handle_t *mesh, meshlink_channel_t *c
 	aio->cb.buffer = cb;
 	aio->priv = priv;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Append the AIO buffer descriptor to the end of the chain */
 	meshlink_aio_buffer_t **p = &channel->aio_receive;
@@ -4050,7 +4066,7 @@ bool meshlink_channel_aio_receive(meshlink_handle_t *mesh, meshlink_channel_t *c
 
 	*p = aio;
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -4072,7 +4088,7 @@ bool meshlink_channel_aio_fd_receive(meshlink_handle_t *mesh, meshlink_channel_t
 	aio->cb.fd = cb;
 	aio->priv = priv;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	/* Append the AIO buffer descriptor to the end of the chain */
 	meshlink_aio_buffer_t **p = &channel->aio_receive;
@@ -4083,7 +4099,7 @@ bool meshlink_channel_aio_fd_receive(meshlink_handle_t *mesh, meshlink_channel_t
 
 	*p = aio;
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 
 	return true;
 }
@@ -4132,7 +4148,7 @@ void meshlink_set_node_channel_timeout(meshlink_handle_t *mesh, meshlink_node_t
 
 	node_t *n = (node_t *)node;
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(!n->utcp) {
 		n->utcp = utcp_init(channel_accept, channel_pre_accept, channel_send, n);
@@ -4142,7 +4158,7 @@ void meshlink_set_node_channel_timeout(meshlink_handle_t *mesh, meshlink_node_t
 
 	utcp_set_user_timeout(n->utcp, timeout);
 
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void update_node_status(meshlink_handle_t *mesh, node_t *n) {
@@ -4186,7 +4202,7 @@ void meshlink_enable_discovery(meshlink_handle_t *mesh, bool enable) {
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 
 	if(mesh->discovery == enable) {
 		goto end;
@@ -4203,7 +4219,7 @@ void meshlink_enable_discovery(meshlink_handle_t *mesh, bool enable) {
 	mesh->discovery = enable;
 
 end:
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 #else
 	(void)mesh;
 	(void)enable;
@@ -4222,10 +4238,10 @@ void meshlink_set_dev_class_timeouts(meshlink_handle_t *mesh, dev_class_t devcla
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->dev_class_traits[devclass].pinginterval = pinginterval;
 	mesh->dev_class_traits[devclass].pingtimeout = pingtimeout;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_dev_class_fast_retry_period(meshlink_handle_t *mesh, dev_class_t devclass, int fast_retry_period) {
@@ -4239,9 +4255,9 @@ void meshlink_set_dev_class_fast_retry_period(meshlink_handle_t *mesh, dev_class
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->dev_class_traits[devclass].fast_retry_period = fast_retry_period;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 extern void meshlink_set_inviter_commits_first(struct meshlink_handle *mesh, bool inviter_commits_first) {
@@ -4250,9 +4266,9 @@ extern void meshlink_set_inviter_commits_first(struct meshlink_handle *mesh, boo
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	mesh->inviter_commits_first = inviter_commits_first;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_external_address_discovery_url(struct meshlink_handle *mesh, const char *url) {
@@ -4266,10 +4282,10 @@ void meshlink_set_external_address_discovery_url(struct meshlink_handle *mesh, c
 		return;
 	}
 
-	pthread_mutex_lock(&mesh->mutex);
+	assert(pthread_mutex_lock(&mesh->mutex) == 0);
 	free(mesh->external_address_url);
 	mesh->external_address_url = url ? xstrdup(url) : NULL;
-	pthread_mutex_unlock(&mesh->mutex);
+	assert(pthread_mutex_unlock(&mesh->mutex) == 0);
 }
 
 void meshlink_set_scheduling_granularity(struct meshlink_handle *mesh, long granularity) {