X-Git-Url: http://git.meshlink.io/?p=meshlink;a=blobdiff_plain;f=src%2Fmeshlink.c;h=6df7c419261fc30f175ef016d00538c295d77f29;hp=7da7a9e1d4daf61a4932201fc9e14d4f7e7d92e6;hb=92283d7342fabd882126a892b2636d57ff0458de;hpb=76c7550c8ab0e9c0ee14a9c396baa008cfb9bc42

diff --git a/src/meshlink.c b/src/meshlink.c
index 7da7a9e1..6df7c419 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -1,6 +1,6 @@
 /*
     meshlink.c -- Implementation of the MeshLink API.
-    Copyright (C) 2014, 2017 Guus Sliepen <guus@meshlink.io>
+    Copyright (C) 2014-2018 Guus Sliepen <guus@meshlink.io>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -56,69 +56,19 @@ meshlink_log_level_t global_log_level;
 //TODO: this can go away completely
 const var_t variables[] = {
 	/* Server configuration */
-	{"AddressFamily", VAR_SERVER},
-	{"AutoConnect", VAR_SERVER | VAR_SAFE},
-	{"BindToAddress", VAR_SERVER | VAR_MULTIPLE},
-	{"BindToInterface", VAR_SERVER},
-	{"Broadcast", VAR_SERVER | VAR_SAFE},
 	{"ConnectTo", VAR_SERVER | VAR_MULTIPLE | VAR_SAFE},
-	{"DecrementTTL", VAR_SERVER},
-	{"Device", VAR_SERVER},
-	{"DeviceType", VAR_SERVER},
-	{"DirectOnly", VAR_SERVER},
-	{"ECDSAPrivateKeyFile", VAR_SERVER},
-	{"ExperimentalProtocol", VAR_SERVER},
-	{"Forwarding", VAR_SERVER},
-	{"GraphDumpFile", VAR_SERVER | VAR_OBSOLETE},
-	{"Hostnames", VAR_SERVER},
-	{"IffOneQueue", VAR_SERVER},
-	{"Interface", VAR_SERVER},
-	{"KeyExpire", VAR_SERVER},
-	{"ListenAddress", VAR_SERVER | VAR_MULTIPLE},
-	{"LocalDiscovery", VAR_SERVER},
-	{"MACExpire", VAR_SERVER},
-	{"MaxConnectionBurst", VAR_SERVER},
-	{"MaxOutputBufferSize", VAR_SERVER},
-	{"MaxTimeout", VAR_SERVER},
-	{"Mode", VAR_SERVER | VAR_SAFE},
 	{"Name", VAR_SERVER},
-	{"PingInterval", VAR_SERVER},
-	{"PingTimeout", VAR_SERVER},
-	{"PriorityInheritance", VAR_SERVER},
-	{"PrivateKey", VAR_SERVER | VAR_OBSOLETE},
-	{"PrivateKeyFile", VAR_SERVER},
-	{"ProcessPriority", VAR_SERVER},
-	{"Proxy", VAR_SERVER},
-	{"ReplayWindow", VAR_SERVER},
-	{"ScriptsExtension", VAR_SERVER},
-	{"ScriptsInterpreter", VAR_SERVER},
-	{"StrictSubnets", VAR_SERVER},
-	{"TunnelServer", VAR_SERVER},
-	{"VDEGroup", VAR_SERVER},
-	{"VDEPort", VAR_SERVER},
 	/* Host configuration */
+	{"CanonicalAddress", VAR_HOST},
 	{"Address", VAR_HOST | VAR_MULTIPLE},
-	{"Cipher", VAR_SERVER | VAR_HOST},
-	{"ClampMSS", VAR_SERVER | VAR_HOST},
-	{"Compression", VAR_SERVER | VAR_HOST},
-	{"Digest", VAR_SERVER | VAR_HOST},
 	{"ECDSAPublicKey", VAR_HOST},
-	{"ECDSAPublicKeyFile", VAR_SERVER | VAR_HOST},
-	{"IndirectData", VAR_SERVER | VAR_HOST},
-	{"MACLength", VAR_SERVER | VAR_HOST},
-	{"PMTU", VAR_SERVER | VAR_HOST},
-	{"PMTUDiscovery", VAR_SERVER | VAR_HOST},
 	{"Port", VAR_HOST},
-	{"PublicKey", VAR_HOST | VAR_OBSOLETE},
-	{"PublicKeyFile", VAR_SERVER | VAR_HOST | VAR_OBSOLETE},
-	{"Subnet", VAR_HOST | VAR_MULTIPLE | VAR_SAFE},
-	{"TCPOnly", VAR_SERVER | VAR_HOST},
-	{"Weight", VAR_HOST | VAR_SAFE},
 	{NULL, 0}
 };
 
 static bool fcopy(FILE *out, const char *filename) {
 	FILE *in = fopen(filename, "r");
+
 	if(!in) {
 		logger(NULL, MESHLINK_ERROR, "Could not open %s: %s\n", filename, strerror(errno));
 		return false;
@@ -126,66 +76,130 @@ static bool fcopy(FILE *out, const char *filename) {
 
 	char buf[1024];
 	size_t len;
-	while((len = fread(buf, 1, sizeof(buf), in)))
+
+	while((len = fread(buf, 1, sizeof(buf), in))) {
 		fwrite(buf, len, 1, out);
+	}
+
 	fclose(in);
 	return true;
 }
 
 static int rstrip(char *value) {
 	int len = strlen(value);
-	while(len && strchr("\t\r\n ", value[len - 1]))
+
+	while(len && strchr("\t\r\n ", value[len - 1])) {
 		value[--len] = 0;
+	}
+
 	return len;
 }
 
 static void scan_for_hostname(const char *filename, char **hostname, char **port) {
 	char line[4096];
-	if(!filename || (*hostname && *port))
+	bool canonical = false;
+
+	if(!filename || (*hostname && *port)) {
 		return;
+	}
 
 	FILE *f = fopen(filename, "r");
-	if(!f)
+
+	if(!f) {
 		return;
+	}
 
 	while(fgets(line, sizeof(line), f)) {
-		if(!rstrip(line))
+		if(!rstrip(line)) {
 			continue;
+		}
+
 		char *p = line, *q;
 		p += strcspn(p, "\t =");
-		if(!*p)
+
+		if(!*p) {
 			continue;
+		}
+
 		q = p + strspn(p, "\t ");
-		if(*q == '=')
+
+		if(*q == '=') {
 			q += 1 + strspn(q + 1, "\t ");
+		}
+
+		// q is now pointing to the hostname
 		*p = 0;
 		p = q + strcspn(q, "\t ");
-		if(*p)
+
+		if(*p) {
 			*p++ = 0;
+		}
+
 		p += strspn(p, "\t ");
 		p[strcspn(p, "\t ")] = 0;
+		// p is now pointing to the port, if present
 
-		if(!*port && !strcasecmp(line, "Port"))
+		if(!*port && !strcasecmp(line, "Port")) {
 			*port = xstrdup(q);
-		else if(!*hostname && !strcasecmp(line, "Address")) {
+		} else if(!canonical && !*hostname && !strcasecmp(line, "Address")) {
+			// Check that the hostname is a symbolic name (it's not a numeric IPv4 or IPv6 address)
+			if(!q[strspn(q, "0123456789.")] || strchr(q, ':')) {
+				continue;
+			}
+
+			*hostname = xstrdup(q);
+
+			if(*p) {
+				free(*port);
+				*port = xstrdup(p);
+			}
+		} else if(!strcasecmp(line, "CanonicalAddress")) {
 			*hostname = xstrdup(q);
+			canonical = true;
+
 			if(*p) {
 				free(*port);
 				*port = xstrdup(p);
 			}
 		}
 
-		if(*hostname && *port)
+		if(canonical && *hostname && *port) {
 			break;
+		}
 	}
 
 	fclose(f);
 }
 
 static bool is_valid_hostname(const char *hostname) {
+	if(!*hostname) {
+		return false;
+	}
+
 	for(const char *p = hostname; *p; p++) {
-		if(!(isalnum(*p) || *p == '-' || *p == '.' || *p == ':'))
+		if(!(isalnum(*p) || *p == '-' || *p == '.' || *p == ':')) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static bool is_valid_port(const char *port) {
+	if(!*port) {
+		return false;
+	}
+
+	if(isdigit(*port)) {
+		char *end;
+		unsigned long int result = strtoul(port, &end, 10);
+		return result && result < 65536 && !*end;
+	}
+
+	for(const char *p = port; *p; p++) {
+		if(!(isalnum(*p) || *p == '-')) {
 			return false;
+		}
 	}
 
 	return true;
@@ -203,45 +217,106 @@ static void set_timeout(int sock, int timeout) {
 	setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
 }
 
+// Find out what local address a socket would use if we connect to the given address.
+// We do this using connect() on a UDP socket, so the kernel has to resolve the address
+// of both endpoints, but this will actually not send any UDP packet.
+static bool getlocaladdrname(char *destaddr, char *host, socklen_t hostlen) {
+	struct addrinfo *rai = NULL;
+	const struct addrinfo hint = {
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_DGRAM,
+		.ai_protocol = IPPROTO_UDP,
+	};
+
+	if(getaddrinfo(destaddr, "80", &hint, &rai) || !rai) {
+		return false;
+	}
+
+	int sock = socket(rai->ai_family, rai->ai_socktype, rai->ai_protocol);
+
+	if(sock == -1) {
+		freeaddrinfo(rai);
+		return false;
+	}
+
+	if(connect(sock, rai->ai_addr, rai->ai_addrlen) && !sockwouldblock(errno)) {
+		freeaddrinfo(rai);
+		return false;
+	}
+
+	freeaddrinfo(rai);
+
+	struct sockaddr_storage sn;
+	socklen_t sl = sizeof(sn);
+
+	if(getsockname(sock, (struct sockaddr *)&sn, &sl)) {
+		return false;
+	}
+
+	if(getnameinfo((struct sockaddr *)&sn, sl, host, hostlen, NULL, 0, NI_NUMERICHOST | NI_NUMERICSERV)) {
+		return false;
+	}
+
+	return true;
+}
+
 char *meshlink_get_external_address(meshlink_handle_t *mesh) {
+	return meshlink_get_external_address_for_family(mesh, AF_UNSPEC);
+}
+
+char *meshlink_get_external_address_for_family(meshlink_handle_t *mesh, int family) {
 	char *hostname = NULL;
 
 	logger(mesh, MESHLINK_DEBUG, "Trying to discover externally visible hostname...\n");
 	struct addrinfo *ai = str2addrinfo("meshlink.io", "80", SOCK_STREAM);
-	struct addrinfo *aip = ai;
 	static const char request[] = "GET http://www.meshlink.io/host.cgi HTTP/1.0\r\n\r\n";
 	char line[256];
 
-	while(aip) {
+	for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
+		if(family != AF_UNSPEC && aip->ai_family != family) {
+			continue;
+		}
+
 		int s = socket(aip->ai_family, aip->ai_socktype, aip->ai_protocol);
+
 		if(s >= 0) {
 			set_timeout(s, 5000);
+
 			if(connect(s, aip->ai_addr, aip->ai_addrlen)) {
 				closesocket(s);
 				s = -1;
 			}
 		}
+
 		if(s >= 0) {
 			send(s, request, sizeof(request) - 1, 0);
 			int len = recv(s, line, sizeof(line) - 1, MSG_WAITALL);
+
 			if(len > 0) {
 				line[len] = 0;
-				if(line[len - 1] == '\n')
+
+				if(line[len - 1] == '\n') {
 					line[--len] = 0;
+				}
+
 				char *p = strrchr(line, '\n');
-				if(p && p[1])
+
+				if(p && p[1]) {
 					hostname = xstrdup(p + 1);
+				}
 			}
+
 			closesocket(s);
-			if(hostname)
+
+			if(hostname) {
 				break;
+			}
 		}
-		aip = aip->ai_next;
-		continue;
 	}
 
-	if(ai)
+	if(ai) {
 		freeaddrinfo(ai);
+	}
 
 	// Check that the hostname is reasonable
 	if(hostname && !is_valid_hostname(hostname)) {
@@ -249,98 +324,147 @@ char *meshlink_get_external_address(meshlink_handle_t *mesh) {
 		hostname = NULL;
 	}
 
-	if(!hostname)
+	// If there is no hostname, determine the address used for an outgoing connection.
+	if(!hostname) {
+		char localaddr[NI_MAXHOST];
+		bool success = false;
+
+		if(family == AF_INET) {
+			success = getlocaladdrname("93.184.216.34", localaddr, sizeof(localaddr));
+		} else if(family == AF_INET6) {
+			success = getlocaladdrname("2606:2800:220:1:248:1893:25c8:1946", localaddr, sizeof(localaddr));
+		}
+
+		if(success) {
+			hostname = xstrdup(localaddr);
+		}
+	}
+
+	if(!hostname) {
 		meshlink_errno = MESHLINK_ERESOLV;
+	}
 
 	return hostname;
 }
 
-static char *get_my_hostname(meshlink_handle_t* mesh) {
-	char *hostname = NULL;
-	char *port = NULL;
+// String comparison which handles NULL arguments
+static bool safe_streq(const char *a, const char *b) {
+	if (!a || !b)
+		return a == b;
+	else
+		return !strcmp(a, b);
+}
+
+// This gets the hostname part for use in invitation URLs
+static char *get_my_hostname(meshlink_handle_t *mesh) {
+	char *hostname[3] = {NULL};
+	char *port[3] = {NULL};
 	char *hostport = NULL;
-	char *name = mesh->self->name;
+
+	// Use the best Address statement in our own host config file
 	char filename[PATH_MAX] = "";
-	FILE *f;
+	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, mesh->self->name);
+	scan_for_hostname(filename, &hostname[0], &port[0]);
 
-	// Use first Address statement in own host config file
-	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, name);
-	scan_for_hostname(filename, &hostname, &port);
+	hostname[1] = meshlink_get_external_address_for_family(mesh, AF_INET);
+	hostname[2] = meshlink_get_external_address_for_family(mesh, AF_INET6);
 
-	if(hostname)
-		goto done;
+	// Concatenate all unique address to the hostport string
+	for (int i = 0; i < 3; i++) {
+		if (!hostname[i])
+			continue;
 
-	hostname = meshlink_get_external_address(mesh);
-	if(!hostname)
-		return NULL;
+		// Ignore duplicate hostnames
+		bool found = false;
 
-	f = fopen(filename, "a");
-	if(f) {
-		fprintf(f, "\nAddress = %s\n", hostname);
-		fclose(f);
-	} else
-		logger(mesh, MESHLINK_DEBUG, "Could not append Address to %s: %s\n", filename, strerror(errno));
+		for (int j = 0; i < j; j++) {
+			if (safe_streq(hostname[i], hostname[j]) && safe_streq(port[i], port[j])) {
+				found = true;
+				break;
+			}
+		}
 
-done:
-	if(port) {
-		if(strchr(hostname, ':'))
-			xasprintf(&hostport, "[%s]:%s", hostname, port);
-		else
-			xasprintf(&hostport, "%s:%s", hostname, port);
-	} else {
-		if(strchr(hostname, ':'))
-			xasprintf(&hostport, "[%s]", hostname);
-		else
-			hostport = xstrdup(hostname);
+		if (found) {
+			free(hostname[i]);
+			free(port[i]);
+			hostname[i] = NULL;
+			port[i] = NULL;
+			continue;
+		}
+
+		// Ensure we have the same addresses in our own host config file.
+		char *tmphostport;
+		xasprintf(&tmphostport, "%s %s", hostname[i], port[i] ? port[i] : mesh->myport);
+		append_config_file(mesh, mesh->self->name, "Address", tmphostport);
+		free(tmphostport);
+
+		// Append the address to the hostport string
+		char *newhostport;
+		xasprintf(&newhostport, (strchr(hostname[i], ':') ? "%s%s[%s]:%s" : "%s%s%s:%s"), hostport ? hostport : "", hostport ? "," : "", hostname[i], port[i] ? port[i] : mesh->myport);
+		free(hostname[i]);
+		free(port[i]);
+		free(hostport);
+		hostport = newhostport;
 	}
 
-	free(hostname);
-	free(port);
 	return hostport;
 }
 
 static char *get_line(const char **data) {
-	if(!data || !*data)
+	if(!data || !*data) {
 		return NULL;
+	}
 
-	if(!**data) {
+	if(! **data) {
 		*data = NULL;
 		return NULL;
 	}
 
 	static char line[1024];
 	const char *end = strchr(*data, '\n');
-	size_t len = end ? end - *data : strlen(*data);
+	size_t len = end ? (size_t)(end - *data) : strlen(*data);
+
 	if(len >= sizeof(line)) {
 		logger(NULL, MESHLINK_ERROR, "Maximum line length exceeded!\n");
 		return NULL;
 	}
-	if(len && !isprint(**data))
+
+	if(len && !isprint(**data)) {
 		abort();
+	}
 
 	memcpy(line, *data, len);
 	line[len] = 0;
 
-	if(end)
+	if(end) {
 		*data = end + 1;
-	else
+	} else {
 		*data = NULL;
+	}
 
 	return line;
 }
 
 static char *get_value(const char *data, const char *var) {
 	char *line = get_line(&data);
-	if(!line)
+
+	if(!line) {
 		return NULL;
+	}
 
 	char *sep = line + strcspn(line, " \t=");
 	char *val = sep + strspn(sep, " \t");
-	if(*val == '=')
+
+	if(*val == '=') {
 		val += 1 + strspn(val + 1, " \t");
+	}
+
 	*sep = 0;
-	if(strcasecmp(line, var))
+
+	if(strcasecmp(line, var)) {
 		return NULL;
+	}
+
 	return val;
 }
 
@@ -356,21 +480,26 @@ static bool try_bind(int port) {
 	char portstr[16];
 	snprintf(portstr, sizeof(portstr), "%d", port);
 
-	if(getaddrinfo(NULL, portstr, &hint, &ai) || !ai)
+	if(getaddrinfo(NULL, portstr, &hint, &ai) || !ai) {
 		return false;
+	}
 
 	while(ai) {
 		int fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP);
+
 		if(!fd) {
 			freeaddrinfo(ai);
 			return false;
 		}
+
 		int result = bind(fd, ai->ai_addr, ai->ai_addrlen);
 		closesocket(fd);
+
 		if(result) {
 			freeaddrinfo(ai);
 			return false;
 		}
+
 		ai = ai->ai_next;
 	}
 
@@ -378,15 +507,18 @@ static bool try_bind(int port) {
 	return true;
 }
 
-static int check_port(meshlink_handle_t *mesh) {
+int check_port(meshlink_handle_t *mesh) {
 	for(int i = 0; i < 1000; i++) {
 		int port = 0x1000 + (rand() & 0x7fff);
+
 		if(try_bind(port)) {
 			char filename[PATH_MAX];
 			snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, mesh->name);
 			FILE *f = fopen(filename, "a");
+
 			if(!f) {
-				logger(mesh, MESHLINK_DEBUG, "Please change MeshLink's Port manually.\n");
+				meshlink_errno = MESHLINK_ESTORAGE;
+				logger(mesh, MESHLINK_DEBUG, "Could not store Port.\n");
 				return 0;
 			}
 
@@ -396,12 +528,39 @@ static int check_port(meshlink_handle_t *mesh) {
 		}
 	}
 
-	logger(mesh, MESHLINK_DEBUG, "Please change MeshLink's Port manually.\n");
+	meshlink_errno = MESHLINK_ENETWORK;
+	logger(mesh, MESHLINK_DEBUG, "Could not find any available network port.\n");
 	return 0;
 }
 
+static void deltree(const char *dirname) {
+	DIR *d = opendir(dirname);
+
+	if(d) {
+		struct dirent *ent;
+
+		while((ent = readdir(d))) {
+			if(ent->d_name[0] == '.') {
+				continue;
+			}
+
+			char filename[PATH_MAX];
+			snprintf(filename, sizeof(filename), "%s" SLASH "%s", dirname, ent->d_name);
+
+			if(unlink(filename)) {
+				deltree(filename);
+			}
+		}
+
+		closedir(d);
+	}
+
+	rmdir(dirname);
+}
+
 static bool finalize_join(meshlink_handle_t *mesh) {
 	char *name = xstrdup(get_value(mesh->data, "Name"));
+
 	if(!name) {
 		logger(mesh, MESHLINK_DEBUG, "No Name found in invitation!\n");
 		return false;
@@ -416,6 +575,7 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 	snprintf(filename, sizeof(filename), "%s" SLASH "meshlink.conf", mesh->confbase);
 
 	FILE *f = fopen(filename, "w");
+
 	if(!f) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create file %s: %s\n", filename, strerror(errno));
 		return false;
@@ -423,8 +583,22 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 
 	fprintf(f, "Name = %s\n", name);
 
+	// Wipe all old host config files and invitations
+	snprintf(filename, sizeof(filename), "%s" SLASH "hosts", mesh->confbase);
+	deltree(filename);
+
+	if(mkdir(filename, 0777) && errno != EEXIST) {
+		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", filename, strerror(errno));
+		return false;
+	}
+
+	snprintf(filename, sizeof(filename), "%s" SLASH "invitations", mesh->confbase);
+	deltree(filename);
+
+	// Create a new host config file for ourself
 	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, name);
 	FILE *fh = fopen(filename, "w");
+
 	if(!fh) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create file %s: %s\n", filename, strerror(errno));
 		fclose(f);
@@ -438,34 +612,41 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 
 	while((l = get_line(&p))) {
 		// Ignore comments
-		if(*l == '#')
+		if(*l == '#') {
 			continue;
+		}
 
 		// Split line into variable and value
 		int len = strcspn(l, "\t =");
 		value = l + len;
 		value += strspn(value, "\t ");
+
 		if(*value == '=') {
 			value++;
 			value += strspn(value, "\t ");
 		}
+
 		l[len] = 0;
 
 		// Is it a Name?
 		if(!strcasecmp(l, "Name"))
-			if(strcmp(value, name))
+			if(strcmp(value, name)) {
 				break;
-			else
+			} else {
 				continue;
-		else if(!strcasecmp(l, "NetName"))
+			} else if(!strcasecmp(l, "NetName")) {
 			continue;
+		}
 
-		// Check the list of known variables //TODO: most variables will not be available in meshlink, only name and key will be absolutely necessary
+		// Check the list of known variables
 		bool found = false;
 		int i;
+
 		for(i = 0; variables[i].name; i++) {
-			if(strcasecmp(l, variables[i].name))
+			if(strcasecmp(l, variables[i].name)) {
 				continue;
+			}
+
 			found = true;
 			break;
 		}
@@ -505,16 +686,21 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 		}
 
 		while((l = get_line(&p))) {
-			if(!strcmp(l, "#---------------------------------------------------------------#"))
+			if(!strcmp(l, "#---------------------------------------------------------------#")) {
 				continue;
+			}
+
 			int len = strcspn(l, "\t =");
+
 			if(len == 4 && !strncasecmp(l, "Name", 4)) {
 				value = l + len;
 				value += strspn(value, "\t ");
+
 				if(*value == '=') {
 					value++;
 					value += strspn(value, "\t ");
 				}
+
 				l[len] = 0;
 				break;
 			}
@@ -527,6 +713,7 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 	}
 
 	char *b64key = ecdsa_get_base64_public_key(mesh->self->connection->ecdsa);
+
 	if(!b64key) {
 		fclose(fh);
 		return false;
@@ -540,8 +727,10 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 	sptps_send_record(&(mesh->sptps), 1, b64key, strlen(b64key));
 	free(b64key);
 
+	free(mesh->name);
 	free(mesh->self->name);
 	free(mesh->self->connection->name);
+	mesh->name = xstrdup(name);
 	mesh->self->name = xstrdup(name);
 	mesh->self->connection->name = name;
 
@@ -553,21 +742,29 @@ static bool finalize_join(meshlink_handle_t *mesh) {
 }
 
 static bool invitation_send(void *handle, uint8_t type, const void *data, size_t len) {
-	meshlink_handle_t* mesh = handle;
+	(void)type;
+	meshlink_handle_t *mesh = handle;
+	const char *ptr = data;
+
 	while(len) {
-		int result = send(mesh->sock, data, len, 0);
-		if(result == -1 && errno == EINTR)
+		int result = send(mesh->sock, ptr, len, 0);
+
+		if(result == -1 && errno == EINTR) {
 			continue;
-		else if(result <= 0)
+		} else if(result <= 0) {
 			return false;
-		data += result;
+		}
+
+		ptr += result;
 		len -= result;
 	}
+
 	return true;
 }
 
 static bool invitation_receive(void *handle, uint8_t type, const void *msg, uint16_t len) {
-	meshlink_handle_t* mesh = handle;
+	meshlink_handle_t *mesh = handle;
+
 	switch(type) {
 	case SPTPS_HANDSHAKE:
 		return sptps_send_record(&(mesh->sptps), 0, mesh->cookie, sizeof(mesh)->cookie);
@@ -596,23 +793,28 @@ static bool invitation_receive(void *handle, uint8_t type, const void *msg, uint
 	return true;
 }
 
-static bool recvline(meshlink_handle_t* mesh, size_t len) {
+static bool recvline(meshlink_handle_t *mesh, size_t len) {
 	char *newline = NULL;
 
-	if(!mesh->sock)
+	if(!mesh->sock) {
 		abort();
+	}
 
 	while(!(newline = memchr(mesh->buffer, '\n', mesh->blen))) {
 		int result = recv(mesh->sock, mesh->buffer + mesh->blen, sizeof(mesh)->buffer - mesh->blen, 0);
-		if(result == -1 && errno == EINTR)
+
+		if(result == -1 && errno == EINTR) {
 			continue;
-		else if(result <= 0)
+		} else if(result <= 0) {
 			return false;
+		}
+
 		mesh->blen += result;
 	}
 
-	if(newline - mesh->buffer >= len)
+	if((size_t)(newline - mesh->buffer) >= len) {
 		return false;
+	}
 
 	len = newline - mesh->buffer;
 
@@ -633,18 +835,22 @@ static bool sendline(int fd, char *format, ...) {
 	blen = vsnprintf(buffer, sizeof(buffer), format, ap);
 	va_end(ap);
 
-	if(blen < 1 || blen >= sizeof(buffer))
+	if(blen < 1 || (size_t)blen >= sizeof(buffer)) {
 		return false;
+	}
 
 	buffer[blen] = '\n';
 	blen++;
 
 	while(blen) {
 		int result = send(fd, p, blen, MSG_NOSIGNAL);
-		if(result == -1 && errno == EINTR)
+
+		if(result == -1 && errno == EINTR) {
 			continue;
-		else if(result <= 0)
+		} else if(result <= 0) {
 			return false;
+		}
+
 		p += result;
 		blen -= result;
 	}
@@ -663,11 +869,15 @@ static const char *errstr[] = {
 	[MESHLINK_ESTORAGE] = "Storage error",
 	[MESHLINK_ENETWORK] = "Network error",
 	[MESHLINK_EPEER] = "Error communicating with peer",
+	[MESHLINK_ENOTSUP] = "Operation not supported",
+	[MESHLINK_EBUSY] = "MeshLink instance already in use",
 };
 
 const char *meshlink_strerror(meshlink_errno_t err) {
-	if(err < 0 || err >= sizeof(errstr) / sizeof(*errstr))
+	if((int)err < 0 || err >= sizeof(errstr) / sizeof(*errstr)) {
 		return "Invalid error code";
+	}
+
 	return errstr[err];
 }
 
@@ -682,10 +892,16 @@ static bool ecdsa_keygen(meshlink_handle_t *mesh) {
 		logger(mesh, MESHLINK_DEBUG, "Error during key generation!\n");
 		meshlink_errno = MESHLINK_EINTERNAL;
 		return false;
-	} else
+	} else {
 		logger(mesh, MESHLINK_DEBUG, "Done.\n");
+	}
+
+	if(snprintf(privname, sizeof(privname), "%s" SLASH "ecdsa_key.priv", mesh->confbase) >= PATH_MAX) {
+		logger(mesh, MESHLINK_DEBUG, "Filename too long: %s" SLASH "ecdsa_key.priv\n", mesh->confbase);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return false;
+	}
 
-	snprintf(privname, sizeof(privname), "%s" SLASH "ecdsa_key.priv", mesh->confbase);
 	f = fopen(privname, "wb");
 
 	if(!f) {
@@ -726,55 +942,23 @@ static bool ecdsa_keygen(meshlink_handle_t *mesh) {
 }
 
 static struct timeval idle(event_loop_t *loop, void *data) {
+	(void)loop;
 	meshlink_handle_t *mesh = data;
 	struct timeval t, tmin = {3600, 0};
+
 	for splay_each(node_t, n, mesh->nodes) {
-		if(!n->utcp)
+		if(!n->utcp) {
 			continue;
-		t = utcp_timeout(n->utcp);
-		if(timercmp(&t, &tmin, <))
-			tmin = t;
-	}
-	return tmin;
-}
-
-// Find out what local address a socket would use if we connect to the given address.
-// We do this using connect() on a UDP socket, so the kernel has to resolve the address
-// of both endpoints, but this will actually not send any UDP packet.
-static bool getlocaladdrname(char *destaddr, char *host, socklen_t hostlen) {
-	struct addrinfo *rai = NULL;
-	const struct addrinfo hint = {
-		.ai_family = AF_UNSPEC,
-		.ai_socktype = SOCK_DGRAM,
-		.ai_protocol = IPPROTO_UDP,
-	};
-
-	if(getaddrinfo(destaddr, "80", &hint, &rai) || !rai)
-		return false;
+		}
 
-	int sock = socket(rai->ai_family, rai->ai_socktype, rai->ai_protocol);
-	if(sock == -1) {
-		freeaddrinfo(rai);
-		return false;
-	}
+		t = utcp_timeout(n->utcp);
 
-	if(connect(sock, rai->ai_addr, rai->ai_addrlen) && !sockwouldblock(errno)) {
-		freeaddrinfo(rai);
-		return false;
+		if(timercmp(&t, &tmin, <)) {
+			tmin = t;
+		}
 	}
 
-	freeaddrinfo(rai);
-
-	struct sockaddr_storage sn;
-	socklen_t sl = sizeof(sn);
-
-	if(getsockname(sock, (struct sockaddr *)&sn, &sl))
-		return false;
-
-	if(getnameinfo((struct sockaddr *)&sn, sl, host, hostlen, NULL, 0, NI_NUMERICHOST | NI_NUMERICSERV))
-		return false;
-
-	return true;
+	return tmin;
 }
 
 // Get our local address(es) by simulating connecting to an Internet host.
@@ -822,6 +1006,7 @@ static bool meshlink_setup(meshlink_handle_t *mesh) {
 	}
 
 	FILE *f = fopen(filename, "w");
+
 	if(!f) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create file %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
@@ -833,15 +1018,20 @@ static bool meshlink_setup(meshlink_handle_t *mesh) {
 
 	if(!ecdsa_keygen(mesh)) {
 		meshlink_errno = MESHLINK_EINTERNAL;
+		unlink(filename);
 		return false;
 	}
 
-	check_port(mesh);
+	if(check_port(mesh) == 0) {
+		meshlink_errno = MESHLINK_ENETWORK;
+		unlink(filename);
+		return false;
+	}
 
 	return true;
 }
 
-meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const char* appname, dev_class_t devclass) {
+meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const char *appname, dev_class_t devclass) {
 	// Validate arguments provided by the application
 	bool usingname = false;
 
@@ -859,6 +1049,12 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 		return NULL;
 	}
 
+	if(strchr(appname, ' ')) {
+		logger(NULL, MESHLINK_ERROR, "Invalid appname given!\n");
+		meshlink_errno = MESHLINK_EINVAL;
+		return NULL;
+	}
+
 	if(!name || !*name) {
 		logger(NULL, MESHLINK_ERROR, "No name given!\n");
 		//return NULL;
@@ -868,11 +1064,12 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 			logger(NULL, MESHLINK_ERROR, "Invalid name given!\n");
 			meshlink_errno = MESHLINK_EINVAL;
 			return NULL;
-		} else
+		} else {
 			usingname = true;
+		}
 	}
 
-	if(devclass < 0 || devclass > _DEV_CLASS_MAX) {
+	if((int)devclass < 0 || devclass > _DEV_CLASS_MAX) {
 		logger(NULL, MESHLINK_ERROR, "Invalid devclass given!\n");
 		meshlink_errno = MESHLINK_EINVAL;
 		return NULL;
@@ -882,7 +1079,12 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 	mesh->confbase = xstrdup(confbase);
 	mesh->appname = xstrdup(appname);
 	mesh->devclass = devclass;
-	if(usingname) mesh->name = xstrdup(name);
+	mesh->discovery = true;
+	mesh->invitation_timeout = 604800; // 1 week
+
+	if(usingname) {
+		mesh->name = xstrdup(name);
+	}
 
 	// initialize mutex
 	pthread_mutexattr_t attr;
@@ -894,6 +1096,8 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 	event_loop_init(&mesh->loop);
 	mesh->loop.data = mesh;
 
+	meshlink_queue_init(&mesh->outpacketqueue);
+
 	// Check whether meshlink.conf already exists
 
 	char filename[PATH_MAX];
@@ -914,6 +1118,32 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 		}
 	}
 
+	// Open the configuration file and lock it
+
+	mesh->conffile = fopen(filename, "r");
+
+	if(!mesh->conffile) {
+		logger(NULL, MESHLINK_ERROR, "Cannot not open %s: %s\n", filename, strerror(errno));
+		meshlink_close(mesh);
+		meshlink_errno = MESHLINK_ESTORAGE;
+		return NULL;
+	}
+
+#ifdef FD_CLOEXEC
+	fcntl(fileno(mesh->conffile), F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef HAVE_MINGW
+	// TODO: use _locking()?
+#else
+	if(flock(fileno(mesh->conffile), LOCK_EX | LOCK_NB) != 0) {
+		logger(NULL, MESHLINK_ERROR, "Cannot lock %s: %s\n", filename, strerror(errno));
+		meshlink_close(mesh);
+		meshlink_errno = MESHLINK_EBUSY;
+		return NULL;
+	}
+#endif
+
 	// Read the configuration
 
 	init_configuration(&mesh->config);
@@ -926,7 +1156,9 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name, const c
 
 #ifdef HAVE_MINGW
 	struct WSAData wsa_state;
+
 	WSAStartup(MAKEWORD(2, 2), &wsa_state);
+
 #endif
 
 	// Setup up everything
@@ -1003,14 +1235,20 @@ bool meshlink_start(meshlink_handle_t *mesh) {
 		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->mesh_mutex));
 		return false;
 	}
 
-	mesh->threadstarted=true;
+	mesh->threadstarted = true;
+
+#if HAVE_CATTA
 
-	if(mesh->discovery)
+	if(mesh->discovery) {
 		discovery_start(mesh);
+	}
+
+#endif
 
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 	return true;
@@ -1025,24 +1263,56 @@ void meshlink_stop(meshlink_handle_t *mesh) {
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 	logger(mesh, MESHLINK_DEBUG, "meshlink_stop called\n");
 
+#if HAVE_CATTA
+
 	// Stop discovery
-	if(mesh->discovery)
+	if(mesh->discovery) {
 		discovery_stop(mesh);
+	}
+
+#endif
 
 	// Shut down the main thread
 	event_loop_stop(&mesh->loop);
 
 	// Send ourselves a UDP packet to kick the event loop
-	listen_socket_t *s = &mesh->listen_socket[0];
-	if(sendto(s->udp.fd, "", 1, MSG_NOSIGNAL, &s->sa.sa, SALEN(s->sa.sa)) == -1)
-		logger(mesh, MESHLINK_ERROR, "Could not send a UDP packet to ourself");
+	for(int i = 0; i < mesh->listen_sockets; i++) {
+		sockaddr_t sa;
+		socklen_t salen = sizeof(sa.sa);
 
-	// Wait for the main thread to finish
-	pthread_mutex_unlock(&(mesh->mesh_mutex));
-	pthread_join(mesh->thread, NULL);
-	pthread_mutex_lock(&(mesh->mesh_mutex));
+		if(getsockname(mesh->listen_socket[i].udp.fd, &sa.sa, &salen) == -1) {
+			logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "getsockname", sockstrerror(sockerrno));
+			continue;
+		}
 
-	mesh->threadstarted = false;
+		if(sendto(mesh->listen_socket[i].udp.fd, "", 1, MSG_NOSIGNAL, &sa.sa, salen) == -1) {
+			logger(mesh, MESHLINK_ERROR, "Could not send a UDP packet to ourself: %s", sockstrerror(sockerrno));
+		}
+	}
+
+	if(mesh->threadstarted) {
+		// Wait for the main thread to finish
+		pthread_mutex_unlock(&(mesh->mesh_mutex));
+		pthread_join(mesh->thread, NULL);
+		pthread_mutex_lock(&(mesh->mesh_mutex));
+
+		mesh->threadstarted = false;
+	}
+
+	// Close all metaconnections
+	if(mesh->connections) {
+		for(list_node_t *node = mesh->connections->head, *next; node; node = next) {
+			next = node->next;
+			connection_t *c = node->data;
+			c->outgoing = NULL;
+			terminate_connection(mesh, c, false);
+		}
+	}
+
+	if(mesh->outgoings) {
+		list_delete_list(mesh->outgoings);
+		mesh->outgoings = NULL;
+	}
 
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 }
@@ -1069,38 +1339,27 @@ void meshlink_close(meshlink_handle_t *mesh) {
 	event_loop_exit(&mesh->loop);
 
 #ifdef HAVE_MINGW
-	if(mesh->confbase)
-		WSACleanup();
-#endif
 
-	ecdsa_free(mesh->invitation_key);
-
-	free(mesh->name);
-	free(mesh->appname);
-	free(mesh->confbase);
-	pthread_mutex_destroy(&(mesh->mesh_mutex));
-
-	memset(mesh, 0, sizeof(*mesh));
-
-	free(mesh);
-}
-
-static void deltree(const char *dirname) {
-	DIR *d = opendir(dirname);
-	if(d) {
-		struct dirent *ent;
-		while((ent = readdir(d))) {
-			if(ent->d_name[0] == '.')
-				continue;
-			char filename[PATH_MAX];
-			snprintf(filename, sizeof(filename), "%s" SLASH "%s", dirname, ent->d_name);
-			if(unlink(filename))
-				deltree(filename);
-		}
-		closedir(d);
+	if(mesh->confbase) {
+		WSACleanup();
 	}
-	rmdir(dirname);
-	return;
+
+#endif
+
+	ecdsa_free(mesh->invitation_key);
+
+	free(mesh->name);
+	free(mesh->appname);
+	free(mesh->confbase);
+	pthread_mutex_destroy(&(mesh->mesh_mutex));
+
+	if(mesh->conffile) {
+		fclose(mesh->conffile);
+        }
+
+	memset(mesh, 0, sizeof(*mesh));
+
+	free(mesh);
 }
 
 bool meshlink_destroy(const char *confbase) {
@@ -1150,6 +1409,17 @@ void meshlink_set_node_status_cb(meshlink_handle_t *mesh, meshlink_node_status_c
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 }
 
+void meshlink_set_node_duplicate_cb(meshlink_handle_t *mesh, meshlink_node_duplicate_cb_t cb) {
+	if(!mesh) {
+		meshlink_errno = MESHLINK_EINVAL;
+		return;
+	}
+
+	pthread_mutex_lock(&(mesh->mesh_mutex));
+	mesh->node_duplicate_cb = cb;
+	pthread_mutex_unlock(&(mesh->mesh_mutex));
+}
+
 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->mesh_mutex));
@@ -1171,8 +1441,9 @@ bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const
 		return false;
 	}
 
-	if(!len)
+	if(!len) {
 		return true;
+	}
 
 	if(!data) {
 		meshlink_errno = MESHLINK_EINVAL;
@@ -1181,6 +1452,7 @@ bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const
 
 	// Prepare the packet
 	vpn_packet_t *packet = malloc(sizeof(*packet));
+
 	if(!packet) {
 		meshlink_errno = MESHLINK_ENOMEM;
 		return false;
@@ -1194,8 +1466,8 @@ bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const
 	memset(hdr, 0, sizeof(*hdr));
 	// leave the last byte as 0 to make sure strings are always
 	// null-terminated if they are longer than the buffer
-	strncpy(hdr->destination, destination->name, (sizeof(hdr)->destination) - 1);
-	strncpy(hdr->source, mesh->self->name, (sizeof(hdr)->source) -1);
+	strncpy((char *)hdr->destination, destination->name, (sizeof(hdr)->destination) - 1);
+	strncpy((char *)hdr->source, mesh->self->name, (sizeof(hdr)->source) - 1);
 
 	memcpy(packet->data + sizeof(*hdr), data, len);
 
@@ -1207,15 +1479,18 @@ bool meshlink_send(meshlink_handle_t *mesh, meshlink_node_t *destination, const
 	}
 
 	// Notify event loop
-	signal_trigger(&(mesh->loop),&(mesh->datafromapp));
+	signal_trigger(&(mesh->loop), &(mesh->datafromapp));
 
 	return true;
 }
 
 void meshlink_send_from_queue(event_loop_t *loop, meshlink_handle_t *mesh) {
+	(void)loop;
 	vpn_packet_t *packet = meshlink_queue_pop(&mesh->outpacketqueue);
-	if(!packet)
+
+	if(!packet) {
 		return;
+	}
 
 	mesh->self->in_packets++;
 	mesh->self->in_bytes += packet->len;
@@ -1227,9 +1502,11 @@ ssize_t meshlink_get_pmtu(meshlink_handle_t *mesh, meshlink_node_t *destination)
 		meshlink_errno = MESHLINK_EINVAL;
 		return -1;
 	}
+
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
 	node_t *n = (node_t *)destination;
+
 	if(!n->status.reachable) {
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
 		return 0;
@@ -1248,6 +1525,7 @@ char *meshlink_get_fingerprint(meshlink_handle_t *mesh, meshlink_node_t *node) {
 		meshlink_errno = MESHLINK_EINVAL;
 		return NULL;
 	}
+
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
 	node_t *n = (node_t *)node;
@@ -1260,8 +1538,9 @@ char *meshlink_get_fingerprint(meshlink_handle_t *mesh, meshlink_node_t *node) {
 
 	char *fingerprint = ecdsa_get_base64_public_key(n->ecdsa);
 
-	if(!fingerprint)
+	if(!fingerprint) {
 		meshlink_errno = MESHLINK_EINTERNAL;
+	}
 
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 	return fingerprint;
@@ -1306,8 +1585,10 @@ meshlink_node_t **meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_
 
 	if(result) {
 		meshlink_node_t **p = result;
-		for splay_each(node_t, n, mesh->nodes)
+
+		for splay_each(node_t, n, mesh->nodes) {
 			*p++ = (meshlink_node_t *)n;
+		}
 	} else {
 		*nmemb = 0;
 		free(nodes);
@@ -1360,11 +1641,14 @@ bool meshlink_verify(meshlink_handle_t *mesh, meshlink_node_t *source, const voi
 
 	struct node_t *n = (struct node_t *)source;
 	node_read_ecdsa_public_key(mesh, n);
+
 	if(!n->ecdsa) {
 		meshlink_errno = MESHLINK_EINTERNAL;
 		rval = false;
-	} else
+	} else {
 		rval = ecdsa_verify(((struct node_t *)source)->ecdsa, data, len, signature);
+	}
+
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 	return rval;
 }
@@ -1375,6 +1659,7 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
 	snprintf(filename, sizeof(filename), "%s" SLASH "invitations", mesh->confbase);
+
 	if(mkdir(filename, 0700) && errno != EEXIST) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create directory %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
@@ -1384,6 +1669,7 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 
 	// Count the number of valid invitations, clean up old ones
 	DIR *dir = opendir(filename);
+
 	if(!dir) {
 		logger(mesh, MESHLINK_DEBUG, "Could not read directory %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
@@ -1397,16 +1683,24 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 	time_t deadline = time(NULL) - 604800; // 1 week in the past
 
 	while((ent = readdir(dir))) {
-		if(strlen(ent->d_name) != 24)
+		if(strlen(ent->d_name) != 24) {
 			continue;
+		}
+
 		char invname[PATH_MAX];
 		struct stat st;
-		snprintf(invname, sizeof(invname), "%s" SLASH "%s", filename, ent->d_name);
+
+		if(snprintf(invname, sizeof(invname), "%s" SLASH "%s", filename, ent->d_name) >= PATH_MAX) {
+			logger(mesh, MESHLINK_DEBUG, "Filename too long: %s" SLASH "%s", filename, ent->d_name);
+			continue;
+		}
+
 		if(!stat(invname, &st)) {
-			if(mesh->invitation_key && deadline < st.st_mtime)
+			if(mesh->invitation_key && deadline < st.st_mtime) {
 				count++;
-			else
+			} else {
 				unlink(invname);
+			}
 		} else {
 			logger(mesh, MESHLINK_DEBUG, "Could not stat %s: %s\n", invname, strerror(errno));
 			errno = 0;
@@ -1428,6 +1722,7 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 	// Remove the key if there are no outstanding invitations.
 	if(!count) {
 		unlink(filename);
+
 		if(mesh->invitation_key) {
 			ecdsa_free(mesh->invitation_key);
 			mesh->invitation_key = NULL;
@@ -1441,6 +1736,7 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 
 	// Create a new key if necessary.
 	FILE *f = fopen(filename, "rb");
+
 	if(!f) {
 		if(errno != ENOENT) {
 			logger(mesh, MESHLINK_DEBUG, "Could not read %s: %s\n", filename, strerror(errno));
@@ -1450,25 +1746,30 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 		}
 
 		mesh->invitation_key = ecdsa_generate();
+
 		if(!mesh->invitation_key) {
 			logger(mesh, MESHLINK_DEBUG, "Could not generate a new key!\n");
 			meshlink_errno = MESHLINK_EINTERNAL;
 			pthread_mutex_unlock(&(mesh->mesh_mutex));
 			return false;
 		}
+
 		f = fopen(filename, "wb");
+
 		if(!f) {
 			logger(mesh, MESHLINK_DEBUG, "Could not write %s: %s\n", filename, strerror(errno));
 			meshlink_errno = MESHLINK_ESTORAGE;
 			pthread_mutex_unlock(&(mesh->mesh_mutex));
 			return false;
 		}
+
 		chmod(filename, 0600);
 		ecdsa_write_pem_private_key(mesh->invitation_key, f);
 		fclose(f);
 	} else {
 		mesh->invitation_key = ecdsa_read_pem_private_key(f);
 		fclose(f);
+
 		if(!mesh->invitation_key) {
 			logger(mesh, MESHLINK_DEBUG, "Could not read private key from %s\n", filename);
 			meshlink_errno = MESHLINK_ESTORAGE;
@@ -1479,8 +1780,8 @@ static bool refresh_invitation_key(meshlink_handle_t *mesh) {
 	return mesh->invitation_key;
 }
 
-bool meshlink_add_address(meshlink_handle_t *mesh, const char *address) {
-	if(!mesh || !address) {
+bool meshlink_set_canonical_address(meshlink_handle_t *mesh, meshlink_node_t *node, const char *address, const char *port) {
+	if(!mesh || !node || !address) {
 		meshlink_errno = MESHLINK_EINVAL;
 		return false;
 	}
@@ -1491,15 +1792,32 @@ bool meshlink_add_address(meshlink_handle_t *mesh, const char *address) {
 		return false;
 	}
 
-	bool rval = false;
+	if(port && !is_valid_port(port)) {
+		logger(mesh, MESHLINK_DEBUG, "Invalid character in port: %s\n", address);
+		meshlink_errno = MESHLINK_EINVAL;
+		return false;
+	}
+
+	char *canonical_address;
+
+	if(port) {
+		xasprintf(&canonical_address, "%s %s", address, port);
+	} else {
+		canonical_address = xstrdup(address);
+	}
 
 	pthread_mutex_lock(&(mesh->mesh_mutex));
-	rval = append_config_file(mesh, mesh->self->name, "Address", address);
+	bool rval = modify_config_file(mesh, node->name, "CanonicalAddress", canonical_address, 1);
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 
+	free(canonical_address);
 	return rval;
 }
 
+bool meshlink_add_address(meshlink_handle_t *mesh, const char *address) {
+	return meshlink_set_canonical_address(mesh, (meshlink_node_t *)mesh->self, address, NULL);
+}
+
 bool meshlink_add_external_address(meshlink_handle_t *mesh) {
 	if(!mesh) {
 		meshlink_errno = MESHLINK_EINVAL;
@@ -1507,8 +1825,10 @@ bool meshlink_add_external_address(meshlink_handle_t *mesh) {
 	}
 
 	char *address = meshlink_get_external_address(mesh);
-	if(!address)
+
+	if(!address) {
 		return false;
+	}
 
 	bool rval = false;
 
@@ -1540,8 +1860,9 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
 		return false;
 	}
 
-	if(mesh->myport && port == atoi(mesh->myport))
+	if(mesh->myport && port == atoi(mesh->myport)) {
 		return true;
+	}
 
 	if(!try_bind(port)) {
 		meshlink_errno = MESHLINK_ENETWORK;
@@ -1551,6 +1872,7 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
 	bool rval = false;
 
 	pthread_mutex_lock(&(mesh->mesh_mutex));
+
 	if(mesh->threadstarted) {
 		meshlink_errno = MESHLINK_EINVAL;
 		goto done;
@@ -1567,12 +1889,13 @@ bool meshlink_set_port(meshlink_handle_t *mesh, int port) {
 
 	init_configuration(&mesh->config);
 
-	if(!read_server_config(mesh))
+	if(!read_server_config(mesh)) {
 		meshlink_errno = MESHLINK_ESTORAGE;
-	else if(!setup_network(mesh))
+	} else if(!setup_network(mesh)) {
 		meshlink_errno = MESHLINK_ENETWORK;
-	else
+	} else {
 		rval = true;
+	}
 
 done:
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
@@ -1580,6 +1903,10 @@ done:
 	return rval;
 }
 
+void meshlink_set_invitation_timeout(meshlink_handle_t *mesh, int timeout) {
+	mesh->invitation_timeout = timeout;
+}
+
 char *meshlink_invite(meshlink_handle_t *mesh, const char *name) {
 	if(!mesh) {
 		meshlink_errno = MESHLINK_EINVAL;
@@ -1599,6 +1926,7 @@ char *meshlink_invite(meshlink_handle_t *mesh, const char *name) {
 	// Ensure no host configuration file with that name exists
 	char filename[PATH_MAX];
 	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, name);
+
 	if(!access(filename, F_OK)) {
 		logger(mesh, MESHLINK_DEBUG, "A host config file for %s already exists!\n", name);
 		meshlink_errno = MESHLINK_EEXIST;
@@ -1616,6 +1944,7 @@ char *meshlink_invite(meshlink_handle_t *mesh, const char *name) {
 
 	// Get the local address
 	char *address = get_my_hostname(mesh);
+
 	if(!address) {
 		logger(mesh, MESHLINK_DEBUG, "No Address known for ourselves!\n");
 		meshlink_errno = MESHLINK_ERESOLV;
@@ -1655,36 +1984,43 @@ char *meshlink_invite(meshlink_handle_t *mesh, const char *name) {
 	// Create a file containing the details of the invitation.
 	snprintf(filename, sizeof(filename), "%s" SLASH "invitations" SLASH "%s", mesh->confbase, cookiehash);
 	int ifd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
+
 	if(!ifd) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create invitation file %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
 		return NULL;
 	}
+
 	FILE *f = fdopen(ifd, "w");
-	if(!f)
+
+	if(!f) {
 		abort();
+	}
 
 	// Fill in the details.
 	fprintf(f, "Name = %s\n", name);
-	//if(netname)
-	//      fprintf(f, "NetName = %s\n", netname);
 	fprintf(f, "ConnectTo = %s\n", mesh->self->name);
 
 	// Copy Broadcast and Mode
 	snprintf(filename, sizeof(filename), "%s" SLASH "meshlink.conf", mesh->confbase);
 	FILE *tc = fopen(filename,  "r");
+
 	if(tc) {
 		char buf[1024];
+
 		while(fgets(buf, sizeof(buf), tc)) {
 			if((!strncasecmp(buf, "Mode", 4) && strchr(" \t=", buf[4]))
 			                || (!strncasecmp(buf, "Broadcast", 9) && strchr(" \t=", buf[9]))) {
 				fputs(buf, f);
+
 				// Make sure there is a newline character.
-				if(!strchr(buf, '\n'))
+				if(!strchr(buf, '\n')) {
 					fputc('\n', f);
+				}
 			}
 		}
+
 		fclose(tc);
 	} else {
 		logger(mesh, MESHLINK_DEBUG, "Could not create %s: %s\n", filename, strerror(errno));
@@ -1717,45 +2053,42 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
+	//Before doing meshlink_join make sure we are not connected to another mesh
+	if(mesh->threadstarted) {
+		logger(mesh, MESHLINK_DEBUG, "Already connected to a mesh\n");
+		meshlink_errno = MESHLINK_EINVAL;
+		pthread_mutex_unlock(&(mesh->mesh_mutex));
+		return false;
+	}
+
 	//TODO: think of a better name for this variable, or of a different way to tokenize the invitation URL.
 	char copy[strlen(invitation) + 1];
 	strcpy(copy, invitation);
 
-	// Split the invitation URL into hostname, port, key hash and cookie.
+	// Split the invitation URL into a list of hostname/port tuples, a key hash and a cookie.
 
 	char *slash = strchr(copy, '/');
-	if(!slash)
+
+	if(!slash) {
 		goto invalid;
+	}
 
 	*slash++ = 0;
 
-	if(strlen(slash) != 48)
+	if(strlen(slash) != 48) {
 		goto invalid;
+	}
 
 	char *address = copy;
 	char *port = NULL;
-	if(*address == '[') {
-		address++;
-		char *bracket = strchr(address, ']');
-		if(!bracket)
-			goto invalid;
-		*bracket = 0;
-		if(bracket[1] == ':')
-			port = bracket + 2;
-	} else {
-		port = strchr(address, ':');
-		if(port)
-			*port++ = 0;
-	}
-
-	if(!port)
-		goto invalid;
 
-	if(!b64decode(slash, mesh->hash, 18) || !b64decode(slash + 24, mesh->cookie, 18))
+	if(!b64decode(slash, mesh->hash, 18) || !b64decode(slash + 24, mesh->cookie, 18)) {
 		goto invalid;
+	}
 
 	// Generate a throw-away key for the invitation.
 	ecdsa_t *key = ecdsa_generate();
+
 	if(!key) {
 		meshlink_errno = MESHLINK_EINTERNAL;
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
@@ -1763,40 +2096,82 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	}
 
 	char *b64key = ecdsa_get_base64_public_key(key);
+	char *comma;
+	mesh->sock = -1;
 
-	//Before doing meshlink_join make sure we are not connected to another mesh
-	if(mesh->threadstarted)
-		goto invalid;
+	while(address && *address) {
+		// We allow commas in the address part to support multiple addresses in one invitation URL.
+		comma = strchr(address, ',');
 
-	// Connect to the meshlink daemon mentioned in the URL.
-	struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
-	if(!ai) {
-		meshlink_errno = MESHLINK_ERESOLV;
-		pthread_mutex_unlock(&(mesh->mesh_mutex));
-		return false;
-	}
+		if(comma) {
+			*comma++ = 0;
+		}
 
-	mesh->sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
-	if(mesh->sock <= 0) {
-		logger(mesh, MESHLINK_DEBUG, "Could not open socket: %s\n", strerror(errno));
-		freeaddrinfo(ai);
-		meshlink_errno = MESHLINK_ENETWORK;
-		pthread_mutex_unlock(&(mesh->mesh_mutex));
-		return false;
-	}
+		// Split of the port
+		port = strrchr(address, ':');
+
+		if(!port) {
+			goto invalid;
+		}
 
-	set_timeout(mesh->sock, 5000);
+		*port++ = 0;
 
-	if(connect(mesh->sock, ai->ai_addr, ai->ai_addrlen)) {
-		logger(mesh, MESHLINK_DEBUG, "Could not connect to %s port %s: %s\n", address, port, strerror(errno));
-		closesocket(mesh->sock);
-		freeaddrinfo(ai);
-		meshlink_errno = MESHLINK_ENETWORK;
-		pthread_mutex_unlock(&(mesh->mesh_mutex));
-		return false;
+		// IPv6 address are enclosed in brackets, per RFC 3986
+		if(*address == '[') {
+			address++;
+			char *bracket = strchr(address, ']');
+
+			if(!bracket) {
+				goto invalid;
+			}
+
+			*bracket++ = 0;
+
+			if(*bracket) {
+				goto invalid;
+			}
+		}
+
+		// Connect to the meshlink daemon mentioned in the URL.
+		struct addrinfo *ai = str2addrinfo(address, port, SOCK_STREAM);
+
+		if(ai) {
+			for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
+				mesh->sock = socket(aip->ai_family, aip->ai_socktype, aip->ai_protocol);
+
+				if(mesh->sock == -1) {
+					logger(mesh, MESHLINK_DEBUG, "Could not open socket: %s\n", strerror(errno));
+					meshlink_errno = MESHLINK_ENETWORK;
+					continue;
+				}
+
+				set_timeout(mesh->sock, 5000);
+
+				if(connect(mesh->sock, aip->ai_addr, aip->ai_addrlen)) {
+					logger(mesh, MESHLINK_DEBUG, "Could not connect to %s port %s: %s\n", address, port, strerror(errno));
+					meshlink_errno = MESHLINK_ENETWORK;
+					closesocket(mesh->sock);
+					mesh->sock = -1;
+					continue;
+				}
+			}
+
+			freeaddrinfo(ai);
+		} else {
+			meshlink_errno = MESHLINK_ERESOLV;
+		}
+
+		if(mesh->sock != -1 || !comma) {
+			break;
+		}
+
+		address = comma;
 	}
 
-	freeaddrinfo(ai);
+	if(mesh->sock == -1) {
+		pthread_mutex_unlock(&mesh->mesh_mutex);
+		return false;
+	}
 
 	logger(mesh, MESHLINK_DEBUG, "Connected to %s port %s...\n", address, port);
 
@@ -1804,7 +2179,7 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 
 	mesh->blen = 0;
 
-	if(!sendline(mesh->sock, "0 ?%s %d.%d", b64key, PROT_MAJOR, 1)) {
+	if(!sendline(mesh->sock, "0 ?%s %d.%d %s", b64key, PROT_MAJOR, 1, mesh->appname)) {
 		logger(mesh, MESHLINK_DEBUG, "Error sending request to %s port %s: %s\n", address, port, strerror(errno));
 		closesocket(mesh->sock);
 		meshlink_errno = MESHLINK_ENETWORK;
@@ -1828,12 +2203,14 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	// Check if the hash of the key he gave us matches the hash in the URL.
 	char *fingerprint = mesh->line + 2;
 	char hishash[64];
+
 	if(sha512(fingerprint, strlen(fingerprint), hishash)) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create hash\n%s\n", mesh->line + 2);
 		meshlink_errno = MESHLINK_EINTERNAL;
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
 		return false;
 	}
+
 	if(memcmp(hishash, mesh->hash, 18)) {
 		logger(mesh, MESHLINK_DEBUG, "Peer has an invalid key!\n%s\n", mesh->line + 2);
 		meshlink_errno = MESHLINK_EPEER;
@@ -1843,6 +2220,7 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	}
 
 	ecdsa_t *hiskey = ecdsa_set_base64_public_key(fingerprint);
+
 	if(!hiskey) {
 		meshlink_errno = MESHLINK_EINTERNAL;
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
@@ -1867,8 +2245,10 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 
 	while((len = recv(mesh->sock, mesh->line, sizeof(mesh)->line, 0))) {
 		if(len < 0) {
-			if(errno == EINTR)
+			if(errno == EINTR) {
 				continue;
+			}
+
 			logger(mesh, MESHLINK_DEBUG, "Error reading data from %s port %s: %s\n", address, port, strerror(errno));
 			meshlink_errno = MESHLINK_ENETWORK;
 			pthread_mutex_unlock(&(mesh->mesh_mutex));
@@ -1898,7 +2278,7 @@ bool meshlink_join(meshlink_handle_t *mesh, const char *invitation) {
 	return true;
 
 invalid:
-	logger(mesh, MESHLINK_DEBUG, "Invalid invitation URL or you are already connected to a Mesh ?\n");
+	logger(mesh, MESHLINK_DEBUG, "Invalid invitation URL\n");
 	meshlink_errno = MESHLINK_EINVAL;
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
 	return false;
@@ -1915,6 +2295,7 @@ char *meshlink_export(meshlink_handle_t *mesh) {
 	char filename[PATH_MAX];
 	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, mesh->self->name);
 	FILE *f = fopen(filename, "r");
+
 	if(!f) {
 		logger(mesh, MESHLINK_DEBUG, "Could not open %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
@@ -1929,9 +2310,11 @@ char *meshlink_export(meshlink_handle_t *mesh) {
 	size_t len = fsize + 9 + strlen(mesh->self->name);
 	char *buf = xmalloc(len);
 	snprintf(buf, len, "Name = %s\n", mesh->self->name);
+
 	if(fread(buf + len - fsize - 1, fsize, 1, f) != 1) {
 		logger(mesh, MESHLINK_DEBUG, "Error reading from %s: %s\n", filename, strerror(errno));
 		fclose(f);
+		free(buf);
 		meshlink_errno = MESHLINK_ESTORAGE;
 		pthread_mutex_unlock(&(mesh->mesh_mutex));
 		return NULL;
@@ -1960,6 +2343,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 	}
 
 	char *end = strchr(data + 7, '\n');
+
 	if(!end) {
 		logger(mesh, MESHLINK_DEBUG, "Invalid data\n");
 		meshlink_errno = MESHLINK_EPEER;
@@ -1971,6 +2355,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 	char name[len + 1];
 	memcpy(name, data + 7, len);
 	name[len] = 0;
+
 	if(!check_id(name)) {
 		logger(mesh, MESHLINK_DEBUG, "Invalid Name\n");
 		meshlink_errno = MESHLINK_EPEER;
@@ -1980,6 +2365,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 
 	char filename[PATH_MAX];
 	snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", mesh->confbase, name);
+
 	if(!access(filename, F_OK)) {
 		logger(mesh, MESHLINK_DEBUG, "File %s already exists, not importing\n", filename);
 		meshlink_errno = MESHLINK_EEXIST;
@@ -1995,6 +2381,7 @@ bool meshlink_import(meshlink_handle_t *mesh, const char *data) {
 	}
 
 	FILE *f = fopen(filename, "w");
+
 	if(!f) {
 		logger(mesh, MESHLINK_DEBUG, "Could not create %s: %s\n", filename, strerror(errno));
 		meshlink_errno = MESHLINK_ESTORAGE;
@@ -2020,15 +2407,21 @@ void meshlink_blacklist(meshlink_handle_t *mesh, meshlink_node_t *node) {
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
 	node_t *n;
-	n = (node_t*)node;
-	n->status.blacklisted=true;
-	logger(mesh, MESHLINK_DEBUG, "Blacklisted %s.\n",node->name);
+	n = (node_t *)node;
+	n->status.blacklisted = true;
+	logger(mesh, MESHLINK_DEBUG, "Blacklisted %s.\n", node->name);
 
 	//Make blacklisting persistent in the config file
 	append_config_file(mesh, n->name, "blacklisted", "yes");
 
+	//Immediately terminate any connections we have with the blacklisted node
+	for list_each(connection_t, c, mesh->connections) {
+		if(c->node == n) {
+			terminate_connection(mesh, c, c->status.active);
+		}
+	}
+
 	pthread_mutex_unlock(&(mesh->mesh_mutex));
-	return;
 }
 
 void meshlink_whitelist(meshlink_handle_t *mesh, meshlink_node_t *node) {
@@ -2056,12 +2449,14 @@ void meshlink_set_default_blacklist(meshlink_handle_t *mesh, bool blacklist) {
  * See header file for detailed comment.
  */
 void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node, const struct sockaddr *addr) {
-	if(!mesh || !node || !addr)
+	if(!mesh || !node || !addr) {
 		return;
+	}
 
 	// Ignore hints about ourself.
-	if((node_t *)node == mesh->self)
+	if((node_t *)node == mesh->self) {
 		return;
+	}
 
 	pthread_mutex_lock(&(mesh->mesh_mutex));
 
@@ -2070,10 +2465,12 @@ void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node, const
 
 	if(host && port) {
 		xasprintf(&str, "%s %s", host, port);
-		if((strncmp("fe80",host,4) != 0) && (strncmp("127.",host,4) != 0) && (strcmp("localhost",host) !=0))
-			append_config_file(mesh, node->name, "Address", str);
-		else
+
+		if((strncmp("fe80", host, 4) != 0) && (strncmp("127.", host, 4) != 0) && (strcmp("localhost", host) != 0)) {
+			modify_config_file(mesh, node->name, "Address", str, 5);
+		} else {
 			logger(mesh, MESHLINK_DEBUG, "Not adding Link Local IPv6 Address to config\n");
+		}
 	}
 
 	free(str);
@@ -2084,103 +2481,65 @@ void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node, const
 	// @TODO do we want to fire off a connection attempt right away?
 }
 
-/* Return an array of edges in the current network graph.
- * Data captures the current state and will not be updated.
- * Caller must deallocate data when done.
- */
-meshlink_edge_t **meshlink_get_all_edges_state(meshlink_handle_t *mesh, meshlink_edge_t **edges, size_t *nmemb) {
-	if(!mesh || !nmemb || (*nmemb && !edges)) {
-		meshlink_errno = MESHLINK_EINVAL;
-		return NULL;
-	}
-
-	pthread_mutex_lock(&(mesh->mesh_mutex));
-
-	meshlink_edge_t **result = NULL;
-	meshlink_edge_t *copy = NULL;
-	int result_size = 0;
-
-	result_size = mesh->edges->count;
-
-	// if result is smaller than edges, we have to dealloc all the excess meshlink_edge_t
-	if(result_size > *nmemb)
-		result = realloc(edges, result_size * sizeof(meshlink_edge_t*));
-	else
-		result = edges;
-
-	if(result) {
-		meshlink_edge_t **p = result;
-		int n = 0;
-		for splay_each(edge_t, e, mesh->edges) {
-			// skip edges that do not represent a two-directional connection
-			if((!e->reverse) || (e->reverse->to != e->from)) {
-				result_size--;
-				continue;
-			}
-			n++;
-			// the first *nmemb members of result can be re-used
-			if(n > *nmemb)
-				copy = xzalloc(sizeof(*copy));
-			else
-				copy = *p;
-			copy->from = (meshlink_node_t*)e->from;
-			copy->to = (meshlink_node_t*)e->to;
-			copy->address = e->address.storage;
-			copy->options = e->options;
-			copy->weight = e->weight;
-			*p++ = copy;
-		}
-		// shrink result to the actual amount of memory used
-		for(int i = *nmemb; i > result_size; i--)
-			free(result[i - 1]);
-		result = realloc(result, result_size * sizeof(meshlink_edge_t*));
-		*nmemb = result_size;
-	} else {
-		*nmemb = 0;
-		meshlink_errno = MESHLINK_ENOMEM;
-	}
-
-	pthread_mutex_unlock(&(mesh->mesh_mutex));
-
-	return result;
-}
-
 static bool channel_pre_accept(struct utcp *utcp, uint16_t port) {
-	//TODO: implement
-	return true;
+	(void)port;
+	node_t *n = utcp->priv;
+	meshlink_handle_t *mesh = n->mesh;
+	return mesh->channel_accept_cb;
 }
 
 static ssize_t channel_recv(struct utcp_connection *connection, const void *data, size_t len) {
 	meshlink_channel_t *channel = connection->priv;
-	if(!channel)
+
+	if(!channel) {
 		abort();
+	}
+
 	node_t *n = channel->node;
 	meshlink_handle_t *mesh = n->mesh;
-	if(channel->receive_cb)
+
+	if(n->status.destroyed) {
+		meshlink_channel_close(mesh, channel);
+	} else if(channel->receive_cb) {
 		channel->receive_cb(mesh, channel, data, len);
+	}
+
 	return len;
 }
 
 static void channel_accept(struct utcp_connection *utcp_connection, uint16_t port) {
 	node_t *n = utcp_connection->utcp->priv;
-	if(!n)
+
+	if(!n) {
 		abort();
+	}
+
 	meshlink_handle_t *mesh = n->mesh;
-	if(!mesh->channel_accept_cb)
+
+	if(!mesh->channel_accept_cb) {
 		return;
+	}
+
 	meshlink_channel_t *channel = xzalloc(sizeof(*channel));
 	channel->node = n;
 	channel->c = utcp_connection;
-	if(mesh->channel_accept_cb(mesh, channel, port, NULL, 0))
+
+	if(mesh->channel_accept_cb(mesh, channel, port, NULL, 0)) {
 		utcp_accept(utcp_connection, channel_recv, channel);
-	else
+	} else {
 		free(channel);
+	}
 }
 
 static ssize_t channel_send(struct utcp *utcp, const void *data, size_t len) {
 	node_t *n = utcp->priv;
+
+	if(n->status.destroyed) {
+		return -1;
+	}
+
 	meshlink_handle_t *mesh = n->mesh;
-	return meshlink_send(mesh, (meshlink_node_t *)n, data, len) ? len : -1;
+	return meshlink_send(mesh, (meshlink_node_t *)n, data, len) ? (ssize_t)len : -1;
 }
 
 void meshlink_set_channel_receive_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_channel_receive_cb_t cb) {
@@ -2193,23 +2552,33 @@ void meshlink_set_channel_receive_cb(meshlink_handle_t *mesh, meshlink_channel_t
 }
 
 static void channel_receive(meshlink_handle_t *mesh, meshlink_node_t *source, const void *data, size_t len) {
+	(void)mesh;
 	node_t *n = (node_t *)source;
-	if(!n->utcp)
+
+	if(!n->utcp) {
 		abort();
+	}
+
 	utcp_recv(n->utcp, data, len);
 }
 
 static void channel_poll(struct utcp_connection *connection, size_t len) {
 	meshlink_channel_t *channel = connection->priv;
-	if(!channel)
+
+	if(!channel) {
 		abort();
+	}
+
 	node_t *n = channel->node;
 	meshlink_handle_t *mesh = n->mesh;
-	if(channel->poll_cb)
+
+	if(channel->poll_cb) {
 		channel->poll_cb(mesh, channel, len);
+	}
 }
 
 void meshlink_set_channel_poll_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, meshlink_channel_poll_cb_t cb) {
+	(void)mesh;
 	channel->poll_cb = cb;
 	utcp_set_poll_cb(channel->c, cb ? channel_poll : NULL);
 }
@@ -2223,37 +2592,49 @@ void meshlink_set_channel_accept_cb(meshlink_handle_t *mesh, meshlink_channel_ac
 	pthread_mutex_lock(&mesh->mesh_mutex);
 	mesh->channel_accept_cb = cb;
 	mesh->receive_cb = channel_receive;
+
 	for splay_each(node_t, n, mesh->nodes) {
-		if(!n->utcp && n != mesh->self)
+		if(!n->utcp && n != mesh->self) {
 			n->utcp = utcp_init(channel_accept, channel_pre_accept, channel_send, n);
+		}
 	}
+
 	pthread_mutex_unlock(&mesh->mesh_mutex);
 }
 
 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) {
+	if(data || len) {
+		abort();        // TODO: handle non-NULL data
+	}
+
 	if(!mesh || !node) {
 		meshlink_errno = MESHLINK_EINVAL;
 		return NULL;
 	}
 
 	node_t *n = (node_t *)node;
+
 	if(!n->utcp) {
 		n->utcp = utcp_init(channel_accept, channel_pre_accept, channel_send, n);
 		mesh->receive_cb = channel_receive;
+
 		if(!n->utcp) {
 			meshlink_errno = errno == ENOMEM ? MESHLINK_ENOMEM : MESHLINK_EINTERNAL;
 			return NULL;
 		}
 	}
+
 	meshlink_channel_t *channel = xzalloc(sizeof(*channel));
 	channel->node = n;
 	channel->receive_cb = cb;
 	channel->c = utcp_connect_ex(n->utcp, port, channel_recv, channel, flags);
+
 	if(!channel->c) {
 		meshlink_errno = errno == ENOMEM ? MESHLINK_ENOMEM : MESHLINK_EINTERNAL;
 		free(channel);
 		return NULL;
 	}
+
 	return channel;
 }
 
@@ -2286,8 +2667,9 @@ ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *chann
 		return -1;
 	}
 
-	if(!len)
+	if(!len) {
 		return 0;
+	}
 
 	if(!data) {
 		meshlink_errno = MESHLINK_EINVAL;
@@ -2303,8 +2685,10 @@ ssize_t meshlink_channel_send(meshlink_handle_t *mesh, meshlink_channel_t *chann
 	ssize_t retval = utcp_send(channel->c, data, len);
 	pthread_mutex_unlock(&mesh->mesh_mutex);
 
-	if(retval < 0)
+	if(retval < 0) {
 		meshlink_errno = MESHLINK_ENETWORK;
+	}
+
 	return retval;
 }
 
@@ -2318,13 +2702,27 @@ uint32_t meshlink_channel_get_flags(meshlink_handle_t *mesh, meshlink_channel_t
 }
 
 void update_node_status(meshlink_handle_t *mesh, node_t *n) {
-	if(n->status.reachable && mesh->channel_accept_cb && !n->utcp)
+	if(n->status.reachable && mesh->channel_accept_cb && !n->utcp) {
 		n->utcp = utcp_init(channel_accept, channel_pre_accept, channel_send, n);
-	if(mesh->node_status_cb)
+	}
+
+	if(mesh->node_status_cb) {
 		mesh->node_status_cb(mesh, (meshlink_node_t *)n, n->status.reachable);
+	}
+}
+
+void handle_duplicate_node(meshlink_handle_t *mesh, node_t *n) {
+	if(!mesh->node_duplicate_cb || n->status.duplicate) {
+		return;
+	}
+
+	n->status.duplicate = true;
+	mesh->node_duplicate_cb(mesh, (meshlink_node_t *)n);
 }
 
 void meshlink_enable_discovery(meshlink_handle_t *mesh, bool enable) {
+#if HAVE_CATTA
+
 	if(!mesh) {
 		meshlink_errno = MESHLINK_EINVAL;
 		return;
@@ -2332,20 +2730,27 @@ void meshlink_enable_discovery(meshlink_handle_t *mesh, bool enable) {
 
 	pthread_mutex_lock(&mesh->mesh_mutex);
 
-	if(mesh->discovery == enable)
+	if(mesh->discovery == enable) {
 		goto end;
+	}
 
 	if(mesh->threadstarted) {
-		if(enable)
+		if(enable) {
 			discovery_start(mesh);
-		else
+		} else {
 			discovery_stop(mesh);
+		}
 	}
 
 	mesh->discovery = enable;
 
 end:
 	pthread_mutex_unlock(&mesh->mesh_mutex);
+#else
+	(void)mesh;
+	(void)enable;
+	meshlink_errno = MESHLINK_ENOTSUP;
+#endif
 }
 
 static void __attribute__((constructor)) meshlink_init(void) {
@@ -2360,7 +2765,7 @@ static void __attribute__((destructor)) meshlink_exit(void) {
 }
 
 /// Device class traits
-dev_class_traits_t dev_class_traits[_DEV_CLASS_MAX +1] = {
+dev_class_traits_t dev_class_traits[_DEV_CLASS_MAX + 1] = {
 	{ .min_connects = 3, .max_connects = 10000, .edge_weight = 1 }, // DEV_CLASS_BACKBONE
 	{ .min_connects = 3, .max_connects = 100, .edge_weight = 3 },   // DEV_CLASS_STATIONARY
 	{ .min_connects = 3, .max_connects = 3, .edge_weight = 6 },             // DEV_CLASS_PORTABLE