X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fdiscovery.c;h=e144c286cbafcefac637b2bbeff50b5e3fa06be7;hb=HEAD;hp=642c7e145fe868df6f12dfc1c7c0e1548ddfd2f7;hpb=69e74943afe4f77a4be52542d4b9b2a47da911f5;p=meshlink

diff --git a/src/discovery.c b/src/discovery.c
index 642c7e14..032b5599 100644
--- a/src/discovery.c
+++ b/src/discovery.c
@@ -1,497 +1,877 @@
+/*
+  discovery.c -- local network discovery
+  Copyright (C) 2014-2021 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
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along
+  with this program; if not, write to the Free Software Foundation, Inc.,
+  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#define __APPLE_USE_RFC_3542
 #include "system.h"
 
-#include <catta/core.h>
-#include <catta/lookup.h>
-#include <catta/publish.h>
-#include <catta/log.h>
-#include <catta/simple-watch.h>
-#include <catta/malloc.h>
-#include <catta/alternative.h>
-#include <catta/error.h>
-
-#if defined(__APPLE__) || defined(__unix) && !defined(__linux)
+#if defined(__APPLE__)
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreFoundation/CFArray.h>
+#include <CoreFoundation/CFString.h>
+#include <SystemConfiguration/SystemConfiguration.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#elif defined(__unix) && !defined(__linux)
+#include <net/if.h>
 #include <net/route.h>
+#include <netinet/in.h>
+#elif defined(__linux)
+#include <asm/types.h>
+#include <net/if.h>
+#include <linux/if_link.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
 #endif
 
+#include "mdns.h"
 #include "meshlink_internal.h"
 #include "event.h"
 #include "discovery.h"
 #include "sockaddr.h"
 #include "logger.h"
+#include "netutl.h"
 #include "node.h"
 #include "connection.h"
+#include "utils.h"
 #include "xalloc.h"
 
 #define MESHLINK_MDNS_SERVICE_TYPE "_%s._tcp"
 #define MESHLINK_MDNS_NAME_KEY "name"
 #define MESHLINK_MDNS_FINGERPRINT_KEY "fingerprint"
 
-static void generate_rand_string(meshlink_handle_t *mesh, char *buffer, size_t size) {
-	assert(size);
+#ifndef MSG_NOSIGNAL
+#define MSG_NOSIGNAL 0
+#endif
+
+#ifndef IPV6_ADD_MEMBERSHIP
+#define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
+#endif
+
+#ifndef IPV6_DROP_MEMBERSHIP
+#define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
+#endif
+
+static const sockaddr_t mdns_address_ipv4 = {
+	.in.sin_family = AF_INET,
+	.in.sin_addr.s_addr = 0xfb0000e0,
+	.in.sin_port = 0xe914,
+};
+
+static const sockaddr_t mdns_address_ipv6 = {
+	.in6.sin6_family = AF_INET6,
+	.in6.sin6_addr.s6_addr[0x0] = 0xff,
+	.in6.sin6_addr.s6_addr[0x1] = 0x02,
+	.in6.sin6_addr.s6_addr[0xf] = 0xfb,
+	.in6.sin6_port = 0xe914,
+};
+
+typedef struct discovery_address {
+	int index;
+	bool up;
+	sockaddr_t address;
+	time_t last_response_sent;
+} discovery_address_t;
+
+static int iface_compare(const void *va, const void *vb) {
+	const int *a = va;
+	const int *b = vb;
+	return *a - *b;
+}
 
-	for(size_t i = 0; i < (size - 1); ++i) {
-		buffer[i] = 'a' + prng(mesh, 'z' - 'a' + 1);
+static int address_compare(const void *va, const void *vb) {
+	const discovery_address_t *a = va;
+	const discovery_address_t *b = vb;
+
+	if(a->index != b->index) {
+		return a->index - b->index;
 	}
 
-	buffer[size - 1] = '\0';
+	return sockaddrcmp_noport(&a->address, &b->address);
 }
 
-static void discovery_entry_group_callback(CattaServer *server, CattaSEntryGroup *group, CattaEntryGroupState state, void *userdata) {
-	(void)server;
-	(void)group;
-	meshlink_handle_t *mesh = userdata;
+static void send_mdns_packet_ipv4(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
+#ifdef IP_MULTICAST_IF
+	struct ip_mreqn mreq = {
+		.imr_address = src->in.sin_addr,
+		.imr_ifindex = index,
+	};
 
-	assert(mesh);
-	assert(mesh->catta_server);
-	assert(mesh->catta_poll);
-
-	/* Called whenever the entry group state changes */
-	switch(state) {
-	case CATTA_ENTRY_GROUP_ESTABLISHED:
-		/* The entry group has been established successfully */
-		logger(mesh, MESHLINK_DEBUG, "Catta Service successfully established.\n");
-		break;
+	if(setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) != 0) {
+		logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv4 socket");
+		return;
+	}
 
-	case CATTA_ENTRY_GROUP_COLLISION:
-		logger(mesh, MESHLINK_WARNING, "Catta Service collision.\n");
-		// @TODO can we just set a new name and retry?
-		break;
+#endif
 
-	case CATTA_ENTRY_GROUP_FAILURE :
-		/* Some kind of failure happened while we were registering our services */
-		logger(mesh, MESHLINK_ERROR, "Catta Entry group failure: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
-		catta_simple_poll_quit(mesh->catta_poll);
-		break;
+#ifdef IP_PKTINFO
+	struct iovec iov  = {
+		.iov_base = data,
+		.iov_len = len,
+	};
+
+	struct in_pktinfo pkti = {
+		.ipi_ifindex = index,
+		.ipi_addr = src->in.sin_addr,
+	};
+
+	union {
+		char buf[CMSG_SPACE(sizeof(pkti))];
+		struct cmsghdr align;
+	} u;
+
+	memset(&u, 0, sizeof(u));
+
+	struct msghdr msg = {
+		.msg_name = (struct sockaddr *) &dest->sa,
+		.msg_namelen = SALEN(dest->sa),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = u.buf,
+		.msg_controllen = sizeof(u.buf),
+	};
+
+	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = IPPROTO_IP;
+	cmsg->cmsg_type = IP_PKTINFO;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
+	memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
+
+	// Send the packet
+	ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+#else
+	(void)index;
+	(void)src;
+
+	// Send the packet
+	ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
+#endif
 
-	case CATTA_ENTRY_GROUP_UNCOMMITED:
-	case CATTA_ENTRY_GROUP_REGISTERING:
-		break;
+	if(result <= 0) {
+		logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
 	}
 }
 
+static void send_mdns_packet_ipv6(meshlink_handle_t *mesh, int fd, int index, const sockaddr_t *src, const sockaddr_t *dest, void *data, size_t len) {
+#ifdef IPV6_MULTICAST_IF
 
-static void discovery_create_services(meshlink_handle_t *mesh) {
-	char *fingerprint = NULL;
-	char *txt_name = NULL;
-	char *txt_fingerprint = NULL;
+	if(setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &index, sizeof(index)) != 0) {
+		logger(mesh, MESHLINK_ERROR, "Could not set outgoing multicast interface on IPv6 socket");
+		return;
+	}
 
-	assert(mesh);
-	assert(mesh->name);
-	assert(mesh->myport);
-	assert(mesh->catta_server);
-	assert(mesh->catta_poll);
-	assert(mesh->catta_servicetype);
-	assert(mesh->self);
+#endif
 
-	logger(mesh, MESHLINK_DEBUG, "Adding service\n");
+#ifdef IPV6_PKTINFO
+	struct iovec iov  = {
+		.iov_base = data,
+		.iov_len = len,
+	};
+
+	struct in6_pktinfo pkti = {
+		.ipi6_ifindex = index,
+		.ipi6_addr = src->in6.sin6_addr,
+	};
+
+	union {
+		char buf[CMSG_SPACE(sizeof(pkti))];
+		struct cmsghdr align;
+	} u;
+
+	memset(&u, 0, sizeof u);
+
+	struct msghdr msg = {
+		.msg_name = (struct sockaddr *) &dest->sa,
+		.msg_namelen = SALEN(dest->sa),
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = u.buf,
+		.msg_controllen = CMSG_LEN(sizeof(pkti)),
+	};
+
+	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = IPPROTO_IPV6;
+	cmsg->cmsg_type = IPV6_PKTINFO;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(pkti));
+	memcpy(CMSG_DATA(cmsg), &pkti, sizeof(pkti));
+
+	// Send the packet
+	ssize_t result = sendmsg(fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+#else
+	(void)index;
+	(void)src;
+
+	// Send the packet
+	ssize_t result = sendto(fd, data, len, MSG_DONTWAIT | MSG_NOSIGNAL, &dest->sa, SALEN(dest->sa));
+#endif
 
-	/* Ifthis is the first time we're called, let's create a new entry group */
-	if(!(mesh->catta_group = catta_s_entry_group_new(mesh->catta_server, discovery_entry_group_callback, mesh))) {
-		logger(mesh, MESHLINK_ERROR, "catta_entry_group_new() failed: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
-		goto fail;
+	if(result <= 0) {
+		logger(mesh, MESHLINK_ERROR, "Error sending multicast packet: %s", strerror(errno));
 	}
+}
 
-	/* Create txt records */
-	fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
-	xasprintf(&txt_name, "%s=%s", MESHLINK_MDNS_NAME_KEY, mesh->name);
-	xasprintf(&txt_fingerprint, "%s=%s", MESHLINK_MDNS_FINGERPRINT_KEY, fingerprint);
+static void send_mdns_packet(meshlink_handle_t *mesh, discovery_address_t *addr, bool response) {
+	// Configure the socket to send the packet to the right interface
+	uint8_t msg[1024];
+	size_t msg_size;
+
+	if(response) {
+		char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
+		static const char *keys[] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
+		const char *values[] = {mesh->name, fingerprint};
+		msg_size = prepare_response(msg, sizeof msg, fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, values);
+		free(fingerprint);
+		addr->last_response_sent = mesh->loop.now.tv_sec;
+	} else {
+		msg_size = prepare_request(msg, sizeof msg, mesh->appname, "tcp");
+	}
 
-	/* Add the service */
-	int ret = 0;
+	switch(addr->address.sa.sa_family) {
+	case AF_INET:
+		send_mdns_packet_ipv4(mesh, mesh->discovery.sockets[0].fd, addr->index, &addr->address, &mdns_address_ipv4, msg, msg_size);
+		break;
+
+	case AF_INET6:
+		send_mdns_packet_ipv6(mesh, mesh->discovery.sockets[1].fd, addr->index, &addr->address, &mdns_address_ipv6, msg, msg_size);
+		break;
 
-	if((ret = catta_server_add_service(mesh->catta_server, mesh->catta_group, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, 0, fingerprint, mesh->catta_servicetype, NULL, NULL, atoi(mesh->myport), txt_name, txt_fingerprint, NULL)) < 0) {
-		logger(mesh, MESHLINK_ERROR, "Failed to add service: %s\n", catta_strerror(ret));
-		goto fail;
+	default:
+		break;
 	}
+}
+
+static void mdns_io_handler(event_loop_t *loop, void *data, int flags) {
+	(void)flags;
+	meshlink_handle_t *mesh = loop->data;
+	io_t *io = data;
+	uint8_t buf[1024];
+	sockaddr_t sa;
+	socklen_t sl = sizeof(sa);
+
+#ifdef IP_PKTINFO
+	struct iovec iov  = {
+		.iov_base = buf,
+		.iov_len = sizeof(buf),
+	};
+
+	union {
+		char buf[1024];
+		struct cmsghdr align;
+	} u;
+
+	struct msghdr msg = {
+		.msg_name = &sa,
+		.msg_namelen = sl,
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = u.buf,
+		.msg_controllen = sizeof(u.buf),
+	};
+
+	ssize_t len = recvmsg(io->fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+
+	sl = msg.msg_namelen;
+#else
+	ssize_t len = recvfrom(io->fd, buf, sizeof(buf), MSG_DONTWAIT, &sa.sa, &sl);
+#endif
+
+	if(len == -1) {
+		if(!sockwouldblock(errno)) {
+			logger(mesh, MESHLINK_ERROR, "Error reading from mDNS discovery socket: %s", strerror(errno));
+			io_set(loop, io, 0);
+		}
 
-	/* Tell the server to register the service */
-	if((ret = catta_s_entry_group_commit(mesh->catta_group)) < 0) {
-		logger(mesh, MESHLINK_ERROR, "Failed to commit entry_group: %s\n", catta_strerror(ret));
-		goto fail;
+		return;
 	}
 
-	goto done;
+	char *name = NULL;
+	uint16_t port = 0;
+	const char *keys[2] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
+	char *values[2] = {NULL, NULL};
 
-fail:
-	catta_simple_poll_quit(mesh->catta_poll);
+	if(parse_response(buf, len, &name, mesh->appname, "tcp", &port, 2, keys, values)) {
+		node_t *n = (node_t *)meshlink_get_node(mesh, values[0]);
 
-done:
-	free(fingerprint);
-	free(txt_name);
-	free(txt_fingerprint);
-}
+		if(n) {
+			if(n != mesh->self) {
+				logger(mesh, MESHLINK_INFO, "Node %s discovered on the local network.\n", n->name);
+			}
 
-static void discovery_server_callback(CattaServer *server, CattaServerState state, void *userdata) {
-	(void)server;
-	meshlink_handle_t *mesh = userdata;
+			switch(sa.sa.sa_family) {
+			case AF_INET:
+				sa.in.sin_port = htons(port);
+				break;
 
-	assert(mesh);
+			case AF_INET6:
+				sa.in6.sin6_port = htons(port);
+				break;
 
-	switch(state) {
-	case CATTA_SERVER_RUNNING:
+			default:
+				logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", n->name);
+				sa.sa.sa_family = AF_UNKNOWN;
+				break;
+			}
 
-		/* The serve has startup successfully and registered its host
-		 * name on the network, so it's time to create our services */
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
-		}
+			if(sa.sa.sa_family != AF_UNKNOWN) {
+				n->catta_address = sa;
+				n->last_connect_try = 0;
+				node_add_recent_address(mesh, n, &sa);
+
+				if(n->connection) {
+					n->connection->last_ping_time = -3600;
+				}
+
+				for list_each(outgoing_t, outgoing, mesh->outgoings) {
+					if(outgoing->node != n) {
+						continue;
+					}
+
+					outgoing->timeout = 0;
 
-		if(!mesh->catta_group) {
-			discovery_create_services(mesh);
+					if(outgoing->ev.cb) {
+						timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
+							0, 0
+						});
+					}
+				}
+			}
 		}
+	} else if(parse_request(buf, len, mesh->appname, "tcp")) {
+		char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
+		const char *response_values[] = {mesh->name, fingerprint};
+		size_t size = prepare_response(buf, sizeof(buf), fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, response_values);
 
-		pthread_mutex_unlock(&mesh->mutex);
+		int index = -1;
+		int family = AF_UNSPEC;
 
-		break;
+		for(struct cmsghdr *cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL; cmptr = CMSG_NXTHDR(&msg, cmptr)) {
+#ifdef IP_PKTINFO
 
-	case CATTA_SERVER_COLLISION: {
-		/* A host name collision happened. Let's pick a new name for the server */
-		char hostname[17];
-		generate_rand_string(mesh, hostname, sizeof(hostname));
+			if(cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO) {
+				struct in_pktinfo *pktinfo = (struct in_pktinfo *) CMSG_DATA(cmptr);
+				index = pktinfo->ipi_ifindex;
+				family = AF_INET;
+				break;
+			} else
+#endif
+#ifdef IPV6_PKTINFO
+				if(cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == IPV6_PKTINFO) {
+					struct in6_pktinfo *pktinfo = (struct in6_pktinfo *) CMSG_DATA(cmptr);
+					index = pktinfo->ipi6_ifindex;
+					family = AF_INET6;
+					break;
+				}
 
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
+#endif
 		}
 
-		assert(mesh->catta_server);
-		assert(mesh->catta_poll);
+		if(index) {
+			// Send a multicast response back using all addresses matching the interface
+			for(int i = 0; i < mesh->discovery.address_count; i++) {
+				discovery_address_t *p = &mesh->discovery.addresses[i];
 
-		int result = catta_server_set_host_name(mesh->catta_server, hostname);
-
-		if(result < 0) {
-			catta_simple_poll_quit(mesh->catta_poll);
+				if(p->index == index && p->address.sa.sa_family == family) {
+					send_mdns_packet(mesh, p, true);
+				}
+			}
+		} else {
+			// Send a unicast response back
+			sendto(io->fd, buf, size, MSG_DONTWAIT | MSG_NOSIGNAL, &sa.sa, sl);
 		}
 
-		pthread_mutex_unlock(&mesh->mutex);
+		free(fingerprint);
 	}
-	break;
 
-	case CATTA_SERVER_REGISTERING:
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
-		}
+	free(name);
 
-		/* Let's drop our registered services. When the server is back
-		 * in CATTA_SERVER_RUNNING state we will register them
-		 * again with the new host name. */
-		if(mesh->catta_group) {
-			catta_s_entry_group_reset(mesh->catta_group);
-			mesh->catta_group = NULL;
-		}
+	for(int i = 0; i < 2; i++) {
+		free(values[i]);
+	}
+}
 
-		pthread_mutex_unlock(&mesh->mutex);
+static void iface_up(meshlink_handle_t *mesh, int index) {
+	int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
 
-		break;
+	if(p) {
+		return;
+	}
 
-	case CATTA_SERVER_FAILURE:
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
-		}
+	mesh->discovery.ifaces = xrealloc(mesh->discovery.ifaces, ++mesh->discovery.iface_count * sizeof(*p));
+	mesh->discovery.ifaces[mesh->discovery.iface_count - 1] = index;
+	qsort(mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
 
-		assert(mesh->catta_server);
-		assert(mesh->catta_poll);
+	// Add multicast membership
+	struct ip_mreqn mreq4 = {
+		.imr_multiaddr = mdns_address_ipv4.in.sin_addr,
+		.imr_ifindex = index,
+	};
 
-		/* Terminate on failure */
-		catta_simple_poll_quit(mesh->catta_poll);
+	setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
+	setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq4, sizeof(mreq4));
 
-		pthread_mutex_unlock(&mesh->mutex);
-		break;
+	struct ipv6_mreq mreq6 = {
+		.ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
+		.ipv6mr_interface = index,
+	};
 
-	case CATTA_SERVER_INVALID:
-		break;
+	setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
+	setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6));
+
+	// Send an announcement for all addresses associated with this interface
+	for(int i = 0; i < mesh->discovery.address_count; i++) {
+		if(mesh->discovery.addresses[i].index == index) {
+			send_mdns_packet(mesh, &mesh->discovery.addresses[i], false);
+		}
 	}
+
+	handle_network_change(mesh, true);
 }
 
-static void discovery_resolve_callback(CattaSServiceResolver *resolver, CattaIfIndex interface_, CattaProtocol protocol, CattaResolverEvent event, const char *name, const char *type, const char *domain, const char *host_name, const CattaAddress *address, uint16_t port, CattaStringList *txt, CattaLookupResultFlags flags, void *userdata) {
-	(void)interface_;
-	(void)protocol;
-	(void)flags;
-	(void)name;
-	(void)type;
-	(void)domain;
-	(void)host_name;
+static void iface_down(meshlink_handle_t *mesh, int index) {
+	int *p = bsearch(&index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(*p), iface_compare);
 
-	meshlink_handle_t *mesh = userdata;
+	if(!p) {
+		return;
+	}
 
-	assert(mesh);
+	// Drop multicast membership
+	struct ip_mreqn mreq4 = {
+		.imr_multiaddr = mdns_address_ipv4.in.sin_addr,
+		.imr_ifindex = index,
+	};
+	setsockopt(mesh->discovery.sockets[0].fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq4, sizeof(mreq4));
 
-	if(event != CATTA_RESOLVER_FOUND) {
-		catta_s_service_resolver_free(resolver);
+	struct ipv6_mreq mreq6 = {
+		.ipv6mr_multiaddr = mdns_address_ipv6.in6.sin6_addr,
+		.ipv6mr_interface = index,
+	};
+	setsockopt(mesh->discovery.sockets[1].fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6));
+
+	memmove(p, p + 1, (mesh->discovery.ifaces + --mesh->discovery.iface_count - p) * sizeof(*p));
+
+	handle_network_change(mesh, mesh->discovery.iface_count);
+}
+
+static void addr_add(meshlink_handle_t *mesh, const discovery_address_t *addr) {
+	discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
+
+	if(p) {
 		return;
 	}
 
-	// retrieve fingerprint
-	CattaStringList *node_name_li = catta_string_list_find(txt, MESHLINK_MDNS_NAME_KEY);
-	CattaStringList *node_fp_li = catta_string_list_find(txt, MESHLINK_MDNS_FINGERPRINT_KEY);
+	bool up = bsearch(&addr->index, mesh->discovery.ifaces, mesh->discovery.iface_count, sizeof(int), iface_compare);
 
-	if(node_name_li && node_fp_li) {
-		char *node_name = (char *)catta_string_list_get_text(node_name_li) + strlen(MESHLINK_MDNS_NAME_KEY);
-		char *node_fp = (char *)catta_string_list_get_text(node_fp_li) + strlen(MESHLINK_MDNS_FINGERPRINT_KEY);
+	mesh->discovery.addresses = xrealloc(mesh->discovery.addresses, ++mesh->discovery.address_count * sizeof(*p));
+	mesh->discovery.addresses[mesh->discovery.address_count - 1] = *addr;
+	mesh->discovery.addresses[mesh->discovery.address_count - 1].up = up;
 
-		if(node_name[0] == '=' && node_fp[0] == '=') {
-			if(pthread_mutex_lock(&mesh->mutex) != 0) {
-				abort();
-			}
+	if(up) {
+		send_mdns_packet(mesh, &mesh->discovery.addresses[mesh->discovery.address_count - 1], false);
+	}
 
-			node_name += 1;
+	qsort(mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
+}
 
-			meshlink_node_t *node = meshlink_get_node(mesh, node_name);
+static void addr_del(meshlink_handle_t *mesh, const discovery_address_t *addr) {
+	discovery_address_t *p = bsearch(addr, mesh->discovery.addresses, mesh->discovery.address_count, sizeof(*p), address_compare);
 
-			if(node) {
-				logger(mesh, MESHLINK_INFO, "Node %s is part of the mesh network.\n", node->name);
+	if(!p) {
+		return;
+	}
 
-				sockaddr_t naddress;
-				memset(&naddress, 0, sizeof(naddress));
+	memmove(p, p + 1, (mesh->discovery.addresses + --mesh->discovery.address_count - p) * sizeof(*p));
+}
 
-				switch(address->proto) {
-				case CATTA_PROTO_INET: {
-					naddress.in.sin_family = AF_INET;
-					naddress.in.sin_port = htons(port);
-					naddress.in.sin_addr.s_addr = address->data.ipv4.address;
-				}
-				break;
+void scan_ifaddrs(meshlink_handle_t *mesh) {
+#ifdef HAVE_GETIFADDRS
+	struct ifaddrs *ifa = NULL;
 
-				case CATTA_PROTO_INET6: {
-					naddress.in6.sin6_family = AF_INET6;
-					naddress.in6.sin6_port = htons(port);
-					memcpy(naddress.in6.sin6_addr.s6_addr, address->data.ipv6.address, sizeof(naddress.in6.sin6_addr.s6_addr));
-				}
-				break;
+	if(getifaddrs(&ifa) == -1) {
+		logger(mesh, MESHLINK_ERROR, "Could not get list of interface addresses: %s", strerror(errno));
+		return;
+	}
 
-				default:
-					naddress.unknown.family = AF_UNKNOWN;
-					break;
-				}
+	// Check for interfaces being removed
+	for(int i = 0; i < mesh->discovery.iface_count;) {
+		bool found = false;
 
-				if(naddress.unknown.family != AF_UNKNOWN) {
-					node_t *n = (node_t *)node;
-					connection_t *c = n->connection;
+		for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
+			if(!ifap->ifa_name) {
+				continue;
+			}
 
-					n->catta_address = naddress;
-					node_add_recent_address(mesh, n, &naddress);
+			int index = if_nametoindex(ifap->ifa_name);
 
-					if(c && c->outgoing && !c->status.active) {
-						c->outgoing->timeout = 0;
+			if(mesh->discovery.ifaces[i] == index) {
+				found = true;
+				break;
+			}
+		}
 
-						if(c->outgoing->ev.cb) {
-							timeout_set(&mesh->loop, &c->outgoing->ev, &(struct timespec) {
-								0, 0
-							});
-						}
+		if(!found) {
+			iface_down(mesh, mesh->discovery.ifaces[i]);
+		} else {
+			i++;
+		}
+	}
 
-						c->last_ping_time = -3600;
-					}
+	// Check for addresses being removed
+	for(int i = 0; i < mesh->discovery.address_count;) {
+		discovery_address_t *p = &mesh->discovery.addresses[i];
+		bool found = false;
 
-				} else {
-					logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", node->name);
-				}
-			} else {
-				logger(mesh, MESHLINK_WARNING, "Node %s is not part of the mesh network.\n", node_name);
+		for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
+			if(!ifap->ifa_name || !ifap->ifa_addr) {
+				continue;
 			}
 
-			pthread_mutex_unlock(&mesh->mutex);
+			int index = if_nametoindex(ifap->ifa_name);
+
+			if(p->index == index && sockaddrcmp_noport(&p->address, (sockaddr_t *)ifap->ifa_addr) == 0) {
+				found = true;
+				break;
+			}
+		}
+
+		if(!found) {
+			(void)addr_del;
+			memmove(p, p + 1, (mesh->discovery.addresses + --mesh->discovery.address_count - p) * sizeof(*p));
+		} else {
+			i++;
 		}
 	}
 
-	catta_s_service_resolver_free(resolver);
-}
+	// Check for interfaces state changes and addresses going up
+	for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
+		if(!ifap->ifa_name) {
+			continue;
+		}
 
-static void discovery_browse_callback(CattaSServiceBrowser *browser, CattaIfIndex interface_, CattaProtocol protocol, CattaBrowserEvent event, const char *name, const char *type, const char *domain, CattaLookupResultFlags flags, void *userdata) {
-	(void)browser;
-	(void)flags;
-	meshlink_handle_t *mesh = userdata;
+		int index = if_nametoindex(ifap->ifa_name);
 
-	/* Called whenever a new services becomes available on the LAN or is removed from the LAN */
-	switch(event) {
-	case CATTA_BROWSER_FAILURE:
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
+		if(ifap->ifa_flags & IFF_UP && ifap->ifa_flags & IFF_MULTICAST && !(ifap->ifa_flags & IFF_LOOPBACK)) {
+			iface_up(mesh, index);
+		} else {
+			iface_down(mesh, index);
 		}
 
-		catta_simple_poll_quit(mesh->catta_poll);
-		pthread_mutex_unlock(&mesh->mutex);
-		break;
-
-	case CATTA_BROWSER_NEW:
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
+		if(!ifap->ifa_addr) {
+			continue;
 		}
 
-		catta_s_service_resolver_new(mesh->catta_server, interface_, protocol, name, type, domain, CATTA_PROTO_UNSPEC, 0, discovery_resolve_callback, mesh);
-		handle_network_change(mesh, ++mesh->catta_interfaces);
-		pthread_mutex_unlock(&mesh->mutex);
-		break;
+		discovery_address_t addr  = {
+			.index = index,
+		};
 
-	case CATTA_BROWSER_REMOVE:
-		if(pthread_mutex_lock(&mesh->mutex) != 0) {
-			abort();
+		sockaddr_t *sa = (sockaddr_t *)ifap->ifa_addr;
+
+		if(sa->sa.sa_family == AF_INET) {
+			memcpy(&addr.address.in, &sa->in, sizeof(sa->in));
+			addr.address.in.sin_port = ntohs(5353);
+		} else if(sa->sa.sa_family == AF_INET6) {
+			memcpy(&addr.address.in6, &sa->in6, sizeof(sa->in6));
+			addr.address.in6.sin6_port = ntohs(5353);
+		} else {
+			addr.address.sa.sa_family = AF_UNKNOWN;
 		}
 
-		handle_network_change(mesh, --mesh->catta_interfaces);
-		pthread_mutex_unlock(&mesh->mutex);
-		break;
+		if(addr.address.sa.sa_family != AF_UNKNOWN) {
+			addr_add(mesh, &addr);
+		}
+	}
 
-	case CATTA_BROWSER_ALL_FOR_NOW:
-	case CATTA_BROWSER_CACHE_EXHAUSTED:
-		break;
+	freeifaddrs(ifa);
+#else
+	(void)mesh;
+#endif
+}
+
+#if defined(__linux)
+static void netlink_getlink(int fd) {
+	static const struct {
+		struct nlmsghdr nlm;
+		struct ifinfomsg ifi;
+	} msg = {
+		.nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifi)),
+		.nlm.nlmsg_type = RTM_GETLINK,
+		.nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.nlm.nlmsg_seq = 1,
+		.ifi.ifi_family = AF_UNSPEC,
+	};
+	send(fd, &msg, msg.nlm.nlmsg_len, 0);
+}
+
+static void netlink_getaddr(int fd) {
+	static const struct {
+		struct nlmsghdr nlm;
+		struct ifaddrmsg ifa;
+	} msg = {
+		.nlm.nlmsg_len = NLMSG_LENGTH(sizeof(msg.ifa)),
+		.nlm.nlmsg_type = RTM_GETADDR,
+		.nlm.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+		.nlm.nlmsg_seq = 2,
+		.ifa.ifa_family = AF_UNSPEC,
+	};
+	send(fd, &msg, msg.nlm.nlmsg_len, 0);
+}
+
+static void netlink_parse_link(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
+	const struct ifinfomsg *ifi = (const struct ifinfomsg *)(nlm + 1);
+
+	if(ifi->ifi_flags & IFF_UP && ifi->ifi_flags & IFF_MULTICAST) {
+		iface_up(mesh, ifi->ifi_index);
+	} else {
+		iface_down(mesh, ifi->ifi_index);
 	}
 }
 
-static void discovery_log_cb(CattaLogLevel level, const char *txt) {
-	meshlink_log_level_t mlevel = MESHLINK_CRITICAL;
+static void netlink_parse_addr(meshlink_handle_t *mesh, const struct nlmsghdr *nlm) {
+	const struct ifaddrmsg *ifa = (const struct ifaddrmsg *)(nlm + 1);
+	const uint8_t *ptr = (const uint8_t *)(ifa + 1);
+	size_t len = nlm->nlmsg_len - (ptr - (const uint8_t *)nlm);
 
-	switch(level) {
-	case CATTA_LOG_ERROR:
-		mlevel = MESHLINK_ERROR;
-		break;
+	while(len >= sizeof(struct rtattr)) {
+		const struct rtattr *rta = (const struct rtattr *)ptr;
 
-	case CATTA_LOG_WARN:
-		mlevel = MESHLINK_WARNING;
-		break;
+		if(rta->rta_len <= 0 || rta->rta_len > len) {
+			break;
+		}
 
-	case CATTA_LOG_NOTICE:
-	case CATTA_LOG_INFO:
-		mlevel = MESHLINK_INFO;
-		break;
+		if(rta->rta_type == IFA_ADDRESS) {
+			discovery_address_t addr  = {
+				.index = ifa->ifa_index,
+			};
+
+			if(rta->rta_len == 8) {
+				addr.address.sa.sa_family = AF_INET;
+				memcpy(&addr.address.in.sin_addr, ptr + 4, 4);
+				addr.address.in.sin_port = ntohs(5353);
+			} else if(rta->rta_len == 20) {
+				addr.address.sa.sa_family = AF_INET6;
+				memcpy(&addr.address.in6.sin6_addr, ptr + 4, 16);
+				addr.address.in6.sin6_port = ntohs(5353);
+				addr.address.in6.sin6_scope_id = ifa->ifa_index;
+			} else {
+				addr.address.sa.sa_family = AF_UNKNOWN;
+			}
 
-	case CATTA_LOG_DEBUG:
-	default:
-		mlevel = MESHLINK_DEBUG;
-		break;
-	}
+			if(addr.address.sa.sa_family != AF_UNKNOWN) {
+				if(nlm->nlmsg_type == RTM_NEWADDR) {
+					addr_add(mesh, &addr);
+				} else {
+					addr_del(mesh, &addr);
+				}
+			}
+		}
 
-	logger(NULL, mlevel, "%s\n", txt);
+		unsigned short rta_len = (rta->rta_len + 3) & ~3;
+		ptr += rta_len;
+		len -= rta_len;
+	}
 }
 
-static void *discovery_loop(void *userdata) {
-	bool status = false;
-	meshlink_handle_t *mesh = userdata;
-	assert(mesh);
+static void netlink_parse(meshlink_handle_t *mesh, const void *data, size_t len) {
+	const uint8_t *ptr = data;
 
-	if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
-		abort();
-	}
+	while(len >= sizeof(struct nlmsghdr)) {
+		const struct nlmsghdr *nlm = (const struct nlmsghdr *)ptr;
 
-	// handle catta logs
-	catta_set_log_function(discovery_log_cb);
+		if(nlm->nlmsg_len > len) {
+			break;
+		}
 
-	// create service type string
-	char appname[strlen(mesh->appname) + 2];
-	strcpy(appname, mesh->appname);
+		switch(nlm->nlmsg_type) {
+		case RTM_NEWLINK:
+		case RTM_DELLINK:
+			netlink_parse_link(mesh, nlm);
+			break;
 
-	for(char *p = appname; *p; p++) {
-		if(!isalnum(*p) && *p != '_' && *p != '-') {
-			*p = '_';
+		case RTM_NEWADDR:
+		case RTM_DELADDR:
+			netlink_parse_addr(mesh, nlm);
 		}
-	}
 
-	if(!appname[1]) {
-		appname[1] = '_';
-		appname[2] = '\0';
+		ptr += nlm->nlmsg_len;
+		len -= nlm->nlmsg_len;
 	}
+}
 
-	size_t servicetype_strlen = sizeof(MESHLINK_MDNS_SERVICE_TYPE) + strlen(appname) + 1;
-	mesh->catta_servicetype = malloc(servicetype_strlen);
+static void netlink_io_handler(event_loop_t *loop, void *data, int flags) {
+	(void)flags;
+	(void)data;
+	meshlink_handle_t *mesh = loop->data;
 
-	if(mesh->catta_servicetype == NULL) {
-		logger(mesh, MESHLINK_ERROR, "Failed to allocate memory for service type string.\n");
-		goto fail;
-	}
+	struct {
+		struct nlmsghdr nlm;
+		char data[16384];
+	} msg;
 
-	snprintf(mesh->catta_servicetype, servicetype_strlen, MESHLINK_MDNS_SERVICE_TYPE, appname);
+	while(true) {
+		ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 
-	// Allocate discovery loop object
-	if(!(mesh->catta_poll = catta_simple_poll_new())) {
-		logger(mesh, MESHLINK_ERROR, "Failed to create discovery poll object.\n");
-		goto fail;
-	}
+		if(result <= 0) {
+			if(result == 0 || errno == EAGAIN || errno == EINTR) {
+				break;
+			}
 
-	// generate some unique host name (we actually do not care about it)
-	char hostname[17];
-	generate_rand_string(mesh, hostname, sizeof(hostname));
+			logger(mesh, MESHLINK_ERROR, "Reading from Netlink socket failed: %s\n", strerror(errno));
+			io_set(loop, &mesh->discovery.pfroute_io, 0);
+		}
 
-	// Let's set the host name for this server.
-	CattaServerConfig config;
-	catta_server_config_init(&config);
-	config.host_name = catta_strdup(hostname);
-	config.publish_workstation = 0;
-	config.disallow_other_stacks = 0;
-	config.publish_hinfo = 0;
-	config.publish_addresses = 1;
-	config.publish_no_reverse = 1;
-	config.allow_point_to_point = 1;
+		if((size_t)result < sizeof(msg.nlm)) {
+			logger(mesh, MESHLINK_ERROR, "Invalid Netlink message\n");
+			break;
+		}
 
-	/* Allocate a new server */
-	int error;
-	const CattaPoll *poller = catta_simple_poll_get(mesh->catta_poll);
+		if(msg.nlm.nlmsg_type == NLMSG_DONE) {
+			if(msg.nlm.nlmsg_seq == 1) {
+				// We just got the result of GETLINK, now send GETADDR.
+				netlink_getaddr(mesh->discovery.pfroute_io.fd);
+			}
+		} else {
+			netlink_parse(mesh, &msg, result);
 
-	if(!poller) {
-		logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
-		goto fail;
+			if(loop->now.tv_sec > mesh->discovery.last_update + 5) {
+				mesh->discovery.last_update = loop->now.tv_sec;
+				handle_network_change(mesh, true);
+			}
+		}
 	}
+}
+#elif defined(__APPLE__)
+static void reachability_change_callback(SCNetworkReachabilityRef reachability, SCNetworkReachabilityFlags flags, void *info) {
+	(void)reachability;
+	(void)flags;
 
-	mesh->catta_server = catta_server_new(poller, &config, discovery_server_callback, mesh, &error);
+	meshlink_handle_t *mesh = info;
 
-	/* Free the configuration data */
-	catta_server_config_free(&config);
+	pthread_mutex_lock(&mesh->mutex);
 
-	/* Check whether creating the server object succeeded */
-	if(!mesh->catta_server) {
-		logger(mesh, MESHLINK_ERROR, "Failed to create discovery server: %s\n", catta_strerror(error));
-		goto fail;
-	}
+	scan_ifaddrs(mesh);
 
-	// Create the service browser
-	if(!(mesh->catta_browser = catta_s_service_browser_new(mesh->catta_server, CATTA_IF_UNSPEC, CATTA_PROTO_UNSPEC, mesh->catta_servicetype, NULL, 0, discovery_browse_callback, mesh))) {
-		logger(mesh, MESHLINK_ERROR, "Failed to create discovery service browser: %s\n", catta_strerror(catta_server_errno(mesh->catta_server)));
-		goto fail;
+	if(mesh->loop.now.tv_sec > mesh->discovery.last_update + 5) {
+		logger(mesh, MESHLINK_INFO, "Network change detected");
+		mesh->discovery.last_update = mesh->loop.now.tv_sec;
+		handle_network_change(mesh, true);
 	}
 
-	status = true;
+	pthread_mutex_unlock(&mesh->mutex);
+}
 
-fail:
+static void *network_change_handler(void *arg) {
+	meshlink_handle_t *mesh = arg;
 
-	pthread_cond_broadcast(&mesh->discovery_cond);
-	pthread_mutex_unlock(&mesh->discovery_mutex);
+	mesh->discovery.runloop = CFRunLoopGetCurrent();
 
-	if(status) {
-		catta_simple_poll_loop(mesh->catta_poll);
-	}
+	SCNetworkReachabilityRef reach_v4 = SCNetworkReachabilityCreateWithName(NULL, "93.184.216.34");
+	SCNetworkReachabilityRef reach_v6 = SCNetworkReachabilityCreateWithName(NULL, "2606:2800:220:1:248:1893:25c8:1946");
 
-	if(mesh->catta_browser) {
-		catta_s_service_browser_free(mesh->catta_browser);
-		mesh->catta_browser = NULL;
-	}
+	SCNetworkReachabilityContext context;
+	memset(&context, 0, sizeof(context));
+	context.info = mesh;
 
-	if(mesh->catta_group) {
-		catta_s_entry_group_reset(mesh->catta_group);
-		catta_s_entry_group_free(mesh->catta_group);
-		mesh->catta_group = NULL;
+	if(reach_v4) {
+		SCNetworkReachabilitySetCallback(reach_v4, reachability_change_callback, &context);
+		SCNetworkReachabilityScheduleWithRunLoop(reach_v4, mesh->discovery.runloop, kCFRunLoopDefaultMode);
+	} else {
+		logger(mesh, MESHLINK_ERROR, "Could not create IPv4 network reachability watcher");
 	}
 
-	if(mesh->catta_server) {
-		catta_server_free(mesh->catta_server);
-		mesh->catta_server = NULL;
+	if(reach_v6) {
+		SCNetworkReachabilitySetCallback(reach_v6, reachability_change_callback, &context);
+		SCNetworkReachabilityScheduleWithRunLoop(reach_v6, mesh->discovery.runloop, kCFRunLoopDefaultMode);
+	} else {
+		logger(mesh, MESHLINK_ERROR, "Could not create IPv6 network reachability watcher");
 	}
 
-	if(mesh->catta_poll) {
-		catta_simple_poll_free(mesh->catta_poll);
-		mesh->catta_poll = NULL;
+	CFRunLoopRun();
+
+	mesh->discovery.runloop = NULL;
+
+	if(reach_v4) {
+		SCNetworkReachabilityUnscheduleFromRunLoop(reach_v4, mesh->discovery.runloop, kCFRunLoopDefaultMode);
+		CFRelease(reach_v4);
 	}
 
-	if(mesh->catta_servicetype) {
-		free(mesh->catta_servicetype);
-		mesh->catta_servicetype = NULL;
+	if(reach_v6) {
+		SCNetworkReachabilityUnscheduleFromRunLoop(reach_v6, mesh->discovery.runloop, kCFRunLoopDefaultMode);
+		CFRelease(reach_v6);
 	}
 
 	return NULL;
 }
+#elif defined(RTM_NEWADDR)
+static void pfroute_parse_iface(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
+	const struct if_msghdr *ifm = (const struct if_msghdr *)rtm;
+
+	if(ifm->ifm_flags & IFF_UP && ifm->ifm_flags & IFF_MULTICAST && !(ifm->ifm_flags & IFF_LOOPBACK)) {
+		iface_up(mesh, ifm->ifm_index);
+	} else {
+		iface_down(mesh, ifm->ifm_index);
+	}
+}
+
+static void pfroute_parse_addr(meshlink_handle_t *mesh, const struct rt_msghdr *rtm) {
+	const struct ifa_msghdr *ifam = (const struct ifa_msghdr *)rtm;
+	const char *p = (const char *)(ifam + 1);
+
+	for(unsigned int i = 1; i; i <<= 1) {
+		if(!(ifam->ifam_addrs & i)) {
+			continue;
+		}
+
+		const sockaddr_t *sa = (const sockaddr_t *)p;
+
+		if(i == RTA_IFA) {
+			discovery_address_t addr = {
+				.index = ifam->ifam_index,
+			};
+
+			if(sa->sa.sa_family == AF_INET) {
+				addr.address.in = sa->in;
+				addr.address.in.sin_port = ntohs(5353);
+			} else if(sa->sa.sa_family == AF_INET6) {
+				addr.address.in6 = sa->in6;
+				addr.address.in6.sin6_port = ntohs(5353);
+			} else {
+				addr.address.sa.sa_family = AF_UNKNOWN;
+			}
+
+			if(addr.address.sa.sa_family != AF_UNKNOWN) {
+				if(ifam->ifam_type == RTM_NEWADDR) {
+					addr_add(mesh, &addr);
+				} else {
+					addr_del(mesh, &addr);
+				}
+			}
+
+			break;
+		}
+
+		size_t len = (sa->sa.sa_len + 3) & ~3;
+		p += len;
+	}
+}
 
-#ifdef RTM_NEWADDR
 static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 	(void)flags;
-	static time_t prev_update;
-	meshlink_handle_t *mesh = data;
+	(void)data;
+	meshlink_handle_t *mesh = loop->data;
 
 	struct {
 		struct rt_msghdr rtm;
@@ -500,7 +880,7 @@ static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 
 	while(true) {
 		msg.rtm.rtm_version = 0;
-		ssize_t result = recv(mesh->pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
+		ssize_t result = recv(mesh->discovery.pfroute_io.fd, &msg, sizeof(msg), MSG_DONTWAIT);
 
 		if(result <= 0) {
 			if(result == 0 || errno == EAGAIN || errno == EINTR) {
@@ -508,7 +888,7 @@ static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 			}
 
 			logger(mesh, MESHLINK_ERROR, "Reading from PFROUTE socket failed: %s\n", strerror(errno));
-			io_set(loop, &mesh->pfroute_io, 0);
+			io_set(loop, &mesh->discovery.pfroute_io, 0);
 		}
 
 		if(msg.rtm.rtm_version != RTM_VERSION) {
@@ -518,13 +898,12 @@ static void pfroute_io_handler(event_loop_t *loop, void *data, int flags) {
 
 		switch(msg.rtm.rtm_type) {
 		case RTM_IFINFO:
+			pfroute_parse_iface(mesh, &msg.rtm);
+			break;
+
 		case RTM_NEWADDR:
 		case RTM_DELADDR:
-			if(loop->now.tv_sec > prev_update + 5) {
-				prev_update = loop->now.tv_sec;
-				handle_network_change(mesh, 1);
-			}
-
+			pfroute_parse_addr(mesh, &msg.rtm);
 			break;
 
 		default:
@@ -538,38 +917,104 @@ bool discovery_start(meshlink_handle_t *mesh) {
 	logger(mesh, MESHLINK_DEBUG, "discovery_start called\n");
 
 	assert(mesh);
-	assert(!mesh->catta_poll);
-	assert(!mesh->catta_server);
-	assert(!mesh->catta_browser);
-	assert(!mesh->discovery_threadstarted);
-	assert(!mesh->catta_servicetype);
 
-	if(pthread_mutex_lock(&mesh->discovery_mutex) != 0) {
-		abort();
+	// Set up multicast sockets for mDNS
+	static const int one = 1;
+	static const int ttl = 255;
+	static const uint8_t one8 = 1;
+	static const uint8_t ttl8 = 255;
+
+	int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+
+	if(fd == -1) {
+		logger(mesh, MESHLINK_ERROR, "Error creating IPv4 socket: %s", strerror(errno));
+	} else {
+
+		sockaddr_t sa4 = {
+			.in.sin_family = AF_INET,
+			.in.sin_port = ntohs(5353),
+		};
+		setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+#ifdef SO_REUSEPORT
+		setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+#endif
+#ifdef IP_PKTINFO
+		setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one));
+#endif
+		setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one8, sizeof(one8));
+		setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl8, sizeof(ttl8));
+
+		if(bind(fd, &sa4.sa, SALEN(sa4.sa)) == -1) {
+			logger(mesh, MESHLINK_ERROR, "Error binding to IPv4 multicast socket: %s", strerror(errno));
+		} else {
+			io_add(&mesh->loop, &mesh->discovery.sockets[0], mdns_io_handler, &mesh->discovery.sockets[0], fd, IO_READ);
+		}
 	}
 
-	// Start the discovery thread
-	if(pthread_create(&mesh->discovery_thread, NULL, discovery_loop, mesh) != 0) {
-		pthread_mutex_unlock(&mesh->discovery_mutex);
-		logger(mesh, MESHLINK_ERROR, "Could not start discovery thread: %s\n", strerror(errno));
-		memset(&mesh->discovery_thread, 0, sizeof(mesh)->discovery_thread);
-		return false;
+	fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+
+	if(fd == -1) {
+		logger(mesh, MESHLINK_ERROR, "Error creating IPv6 socket: %s", strerror(errno));
+	} else {
+		sockaddr_t sa6 = {
+			.in6.sin6_family = AF_INET6,
+			.in6.sin6_port = ntohs(5353),
+		};
+
+		setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+#ifdef SO_REUSEPORT
+		setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+#endif
+#ifdef IPV6_RECVPKTINFO
+		setsockopt(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
+#endif
+		setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+		setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one));
+		setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
+		setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
+
+		if(bind(fd, &sa6.sa, SALEN(sa6.sa)) == -1) {
+			logger(mesh, MESHLINK_ERROR, "Error binding to IPv6 multicast socket: %s", strerror(errno));
+		} else {
+			io_add(&mesh->loop, &mesh->discovery.sockets[1], mdns_io_handler, &mesh->discovery.sockets[1], fd, IO_READ);
+		}
 	}
 
-	pthread_cond_wait(&mesh->discovery_cond, &mesh->discovery_mutex);
-	pthread_mutex_unlock(&mesh->discovery_mutex);
+#if defined(__linux)
+	int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
 
-	mesh->discovery_threadstarted = true;
+	if(sock != -1) {
+		struct sockaddr_nl sa;
+		memset(&sa, 0, sizeof(sa));
+		sa.nl_family = AF_NETLINK;
+		sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
+
+		if(bind(sock, (struct sockaddr *)&sa, sizeof(sa)) != -1) {
+			io_add(&mesh->loop, &mesh->discovery.pfroute_io, netlink_io_handler, NULL, sock, IO_READ);
+			netlink_getlink(sock);
+		} else {
+			logger(mesh, MESHLINK_WARNING, "Could not bind AF_NETLINK socket: %s", strerror(errno));
+			scan_ifaddrs(mesh);
+		}
+	} else {
+		logger(mesh, MESHLINK_WARNING, "Could not open AF_NETLINK socket: %s", strerror(errno));
+		scan_ifaddrs(mesh);
+	}
 
-#ifdef RTM_NEWADDR
+#elif defined(__APPLE__)
+	pthread_create(&mesh->discovery.thread, NULL, network_change_handler, mesh);
+	// TODO: Do we need to wait for the thread to start succesfully?
+	scan_ifaddrs(mesh);
+#elif defined(RTM_NEWADDR)
 	int sock = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
 
 	if(sock != -1) {
-		io_add(&mesh->loop, &mesh->pfroute_io, pfroute_io_handler, mesh, sock, IO_READ);
+		io_add(&mesh->loop, &mesh->discovery.pfroute_io, pfroute_io_handler, NULL, sock, IO_READ);
 	} else {
 		logger(mesh, MESHLINK_WARNING, "Could not open PF_ROUTE socket: %s", strerror(errno));
 	}
 
+	scan_ifaddrs(mesh);
 #endif
 
 	return true;
@@ -580,28 +1025,39 @@ void discovery_stop(meshlink_handle_t *mesh) {
 
 	assert(mesh);
 
-#ifdef RTM_NEWADDR
+	free(mesh->discovery.ifaces);
+	free(mesh->discovery.addresses);
+	mesh->discovery.ifaces = NULL;
+	mesh->discovery.addresses = NULL;
+	mesh->discovery.iface_count = 0;
+	mesh->discovery.address_count = 0;
 
-	if(mesh->pfroute_io.cb) {
-		close(mesh->pfroute_io.fd);
-		io_del(&mesh->loop, &mesh->pfroute_io);
+#if defined(__APPLE__)
+
+	if(mesh->discovery.runloop) {
+		CFRunLoopStop(mesh->discovery.runloop);
+		pthread_join(mesh->discovery.thread, NULL);
 	}
 
 #endif
 
-	// Shut down
-	if(mesh->catta_poll) {
-		catta_simple_poll_quit(mesh->catta_poll);
+	if(mesh->discovery.pfroute_io.cb) {
+		close(mesh->discovery.pfroute_io.fd);
+		io_del(&mesh->loop, &mesh->discovery.pfroute_io);
 	}
 
-	// Wait for the discovery thread to finish
-	if(mesh->discovery_threadstarted == true) {
-		if(pthread_join(mesh->discovery_thread, NULL) != 0) {
-			abort();
+	for(int i = 0; i < 2; i++) {
+		if(mesh->discovery.sockets[i].cb) {
+			close(mesh->discovery.sockets[i].fd);
+			io_del(&mesh->loop, &mesh->discovery.sockets[i]);
 		}
-
-		mesh->discovery_threadstarted = false;
 	}
+}
 
-	mesh->catta_interfaces = 0;
+void discovery_refresh(meshlink_handle_t *mesh) {
+	for(int i = 0; i < mesh->discovery.address_count; i++) {
+		if(mesh->discovery.addresses[i].up) {
+			send_mdns_packet(mesh, &mesh->discovery.addresses[i], false);
+		}
+	}
 }