X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fnet_packet.c;h=30ad3e504c3cf56c68650d9897c2c4551230db28;hb=b3b89e46b1b84fa6cf1726fabe9e9c7bb0d3d831;hp=67ebc223624931baecd4f7fa44761ce1105839f5;hpb=ee1d655f2f1ede6da66b6268974d6f9585c616b3;p=meshlink

diff --git a/src/net_packet.c b/src/net_packet.c
index 67ebc223..30ad3e50 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -1,7 +1,7 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
                   2010      Timothy Redaelli <timothy@redaelli.eu>
                   2010      Brandon Black <blblack@gmail.com>
 
@@ -22,12 +22,6 @@
 
 #include "system.h"
 
-#include <openssl/rand.h>
-#include <openssl/err.h>
-#include <openssl/evp.h>
-#include <openssl/pem.h>
-#include <openssl/hmac.h>
-
 #ifdef HAVE_ZLIB
 #include <zlib.h>
 #endif
@@ -41,14 +35,12 @@
 #include "connection.h"
 #include "crypto.h"
 #include "digest.h"
-#include "device.h"
 #include "ethernet.h"
 #include "graph.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"
 #include "protocol.h"
-#include "process.h"
 #include "route.h"
 #include "utils.h"
 #include "xalloc.h"
@@ -62,6 +54,7 @@ static void send_udppacket(node_t *, vpn_packet_t *);
 
 unsigned replaywin = 16;
 bool localdiscovery = false;
+sockaddr_t localdiscovery_address;
 
 #define MAX_SEQNO 1073741824
 
@@ -70,14 +63,18 @@ bool localdiscovery = false;
    mtuprobes ==    32: send 1 burst, sleep pingtimeout second
    mtuprobes ==    33: no response from other side, restart PMTU discovery process
 
-   Probes are sent in batches of three, with random sizes between the lower and
-   upper boundaries for the MTU thus far discovered.
+   Probes are sent in batches of at least three, with random sizes between the
+   lower and upper boundaries for the MTU thus far discovered.
+
+   After the initial discovery, a fourth packet is added to each batch with a
+   size larger than the currently known PMTU, to test if the PMTU has increased.
 
-   In case local discovery is enabled, a fourth packet is added to each batch,
+   In case local discovery is enabled, another packet is added to each batch,
    which will be broadcast to the local network.
+
 */
 
-static void send_mtu_probe_handler(int fd, short events, void *data) {
+static void send_mtu_probe_handler(void *data) {
 	node_t *n = data;
 	int timeout = 1;
 
@@ -125,13 +122,18 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
 		timeout = pingtimeout;
 	}
 
-	for(int i = 0; i < 3 + localdiscovery; i++) {
+	for(int i = 0; i < 4 + localdiscovery; i++) {
 		int len;
 
-		if(n->maxmtu <= n->minmtu)
+		if(i == 0) {
+			if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
+				continue;
+			len = n->maxmtu + 8;
+		} else if(n->maxmtu <= n->minmtu) {
 			len = n->maxmtu;
-		else
+		} else {
 			len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+		}
 
 		if(len < 64)
 			len = 64;
@@ -140,46 +142,136 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
 		memset(packet.data, 0, 14);
 		randomize(packet.data + 14, len - 14);
 		packet.len = len;
-		if(i >= 3 && n->mtuprobes <= 10)
-			packet.priority = -1;
-		else
-			packet.priority = 0;
+		packet.priority = 0;
+		n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
 
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
 
 		send_udppacket(n, &packet);
 	}
 
+	n->status.broadcast = false;
+	n->probe_counter = 0;
+	gettimeofday(&n->probe_time, NULL);
+
+	/* Calculate the packet loss of incoming traffic by comparing the rate of
+	   packets received to the rate with which the sequence number has increased.
+	 */
+
+	if(n->received > n->prev_received)
+		n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
+	else
+		n->packetloss = n->received_seqno <= n->prev_received_seqno;
+
+	n->prev_received_seqno = n->received_seqno;
+	n->prev_received = n->received;
+
 end:
-	event_add(&n->mtuevent, &(struct timeval){timeout, 0});
+	timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
 }
 
 void send_mtu_probe(node_t *n) {
-	if(!timeout_initialized(&n->mtuevent))
-		timeout_set(&n->mtuevent, send_mtu_probe_handler, n);
-	send_mtu_probe_handler(0, 0, n);
+	timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
+	send_mtu_probe_handler(n);
 }
 
 static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
-	logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
-
 	if(!packet->data[0]) {
-		packet->data[0] = 1;
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe request %d from %s (%s)", packet->len, n->name, n->hostname);
+
+		/* It's a probe request, send back a reply */
+
+		/* Type 2 probe replies were introduced in protocol 17.3 */
+		if ((n->options >> 24) == 3) {
+			uint8_t* data = packet->data;
+			*data++ = 2;
+			uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
+			struct timeval now;
+			gettimeofday(&now, NULL);
+			uint32_t sec = htonl(now.tv_sec); memcpy(data, &sec, 4); data += 4;
+			uint32_t usec = htonl(now.tv_usec); memcpy(data, &usec, 4); data += 4;
+			packet->len = data - packet->data;
+		} else {
+			/* Legacy protocol: n won't understand type 2 probe replies. */
+			packet->data[0] = 1;
+		}
+
+		/* Temporarily set udp_confirmed, so that the reply is sent
+		   back exactly the way it came in. */
+
+		bool udp_confirmed = n->status.udp_confirmed;
+		n->status.udp_confirmed = true;
 		send_udppacket(n, packet);
+		n->status.udp_confirmed = udp_confirmed;
 	} else {
+		length_t probelen = len;
+		if (packet->data[0] == 2) {
+			if (len < 3)
+				logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) MTU probe reply from %s (%s)", n->name, n->hostname);
+			else {
+				uint16_t probelen16; memcpy(&probelen16, packet->data + 1, 2); probelen = ntohs(probelen16);
+			}
+		}
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d MTU probe reply %d from %s (%s)", packet->data[0], probelen, n->name, n->hostname);
+
+		/* It's a valid reply: now we know bidirectional communication
+		   is possible using the address and socket that the reply
+		   packet used. */
+
 		n->status.udp_confirmed = true;
 
+		/* If we haven't established the PMTU yet, restart the discovery process. */
+
 		if(n->mtuprobes > 30) {
+			if (probelen == n->maxmtu + 8) {
+				logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+				n->maxmtu = MTU;
+				n->mtuprobes = 10;
+				return;
+			}
+
 			if(n->minmtu)
 				n->mtuprobes = 30;
 			else
 				n->mtuprobes = 1;
 		}
 
-		if(len > n->maxmtu)
-			len = n->maxmtu;
-		if(n->minmtu < len)
-			n->minmtu = len;
+		/* If applicable, raise the minimum supported MTU */
+
+		if(probelen > n->maxmtu)
+			probelen = n->maxmtu;
+		if(n->minmtu < probelen)
+			n->minmtu = probelen;
+
+		/* Calculate RTT and bandwidth.
+		   The RTT is the time between the MTU probe burst was sent and the first
+		   reply is received. The bandwidth is measured using the time between the
+		   arrival of the first and third probe reply (or type 2 probe requests).
+		 */
+
+		struct timeval now, diff;
+		gettimeofday(&now, NULL);
+		timersub(&now, &n->probe_time, &diff);
+
+		struct timeval probe_timestamp = now;
+		if (packet->data[0] == 2 && packet->len >= 11) {
+			uint32_t sec; memcpy(&sec, packet->data + 3, 4);
+			uint32_t usec; memcpy(&usec, packet->data + 7, 4);
+			probe_timestamp.tv_sec = ntohl(sec);
+			probe_timestamp.tv_usec = ntohl(usec);
+		}
+		
+		n->probe_counter++;
+
+		if(n->probe_counter == 1) {
+			n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
+			n->probe_time = probe_timestamp;
+		} else if(n->probe_counter == 3) {
+			struct timeval probe_timestamp_diff;
+			timersub(&probe_timestamp, &n->probe_time, &probe_timestamp_diff);
+			n->bandwidth = 2.0 * probelen / (probe_timestamp_diff.tv_sec + probe_timestamp_diff.tv_usec * 1e-6);
+			logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, burst bandwidth %.3f Mbit/s, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->bandwidth * 8e-6, n->packetloss * 1e2);
+		}
 	}
 }
 
@@ -258,10 +350,10 @@ static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
 	if(n->status.sptps)
 		return sptps_verify_datagram(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
 
-	if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
+	if(!digest_active(n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest))
 		return false;
 
-	return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
+	return digest_verify(n->indigest, &inpkt->seqno, inpkt->len - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
 }
 
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
@@ -272,19 +364,27 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	size_t outlen;
 
 	if(n->status.sptps) {
+		if(!n->sptps.state) {
+			if(!n->status.waitingforkey) {
+				logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but we haven't exchanged keys yet", n->name, n->hostname);
+				send_req_key(n);
+			} else {
+				logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
+			}
+			return;
+		}
 		sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
 		return;
 	}
 
-	if(!cipher_active(&n->incipher)) {
-		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
-					n->name, n->hostname);
+	if(!cipher_active(n->incipher)) {
+		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
 		return;
 	}
 
 	/* Check packet length */
 
-	if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
+	if(inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest)) {
 		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
 					n->name, n->hostname);
 		return;
@@ -292,20 +392,20 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
 	/* Check the message authentication code */
 
-	if(digest_active(&n->indigest)) {
-		inpkt->len -= n->indigest.maclength;
-		if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+	if(digest_active(n->indigest)) {
+		inpkt->len -= digest_length(n->indigest);
+		if(!digest_verify(n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
 			logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
 			return;
 		}
 	}
 	/* Decrypt the packet */
 
-	if(cipher_active(&n->incipher)) {
+	if(cipher_active(n->incipher)) {
 		outpkt = pkt[nextpkt++];
 		outlen = MAXSIZE;
 
-		if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+		if(!cipher_decrypt(n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 			logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
 			return;
 		}
@@ -349,6 +449,8 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	if(inpkt->seqno > n->received_seqno)
 		n->received_seqno = inpkt->seqno;
 
+	n->received++;
+
 	if(n->received_seqno > MAX_SEQNO)
 		regenerate_key();
 
@@ -381,6 +483,9 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 void receive_tcppacket(connection_t *c, const char *buffer, int len) {
 	vpn_packet_t outpkt;
 
+	if(len > sizeof outpkt.data)
+		return;
+
 	outpkt.len = len;
 	if(c->options & OPTION_TCPONLY)
 		outpkt.priority = 0;
@@ -396,7 +501,7 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
 		logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
 		if(!n->status.waitingforkey)
 			send_req_key(n);
-		else if(n->last_req_key + 10 < time(NULL)) {
+		else if(n->last_req_key + 10 < now.tv_sec) {
 			logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
 			sptps_stop(&n->sptps);
 			n->status.waitingforkey = false;
@@ -438,6 +543,94 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
 	return;
 }
 
+static void choose_udp_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+	/* Latest guess */
+	*sa = &n->address;
+	*sock = n->sock;
+
+	/* If the UDP address is confirmed, use it. */
+	if(n->status.udp_confirmed)
+		return;
+
+	/* Send every third packet to n->address; that could be set
+	   to the node's reflexive UDP address discovered during key
+	   exchange. */
+
+	static int x = 0;
+	if(++x >= 3) {
+		x = 0;
+		return;
+	}
+
+	/* Otherwise, address are found in edges to this node.
+	   So we pick a random edge and a random socket. */
+
+	int i = 0;
+	int j = rand() % n->edge_tree->count;
+	edge_t *candidate = NULL;
+
+	for splay_each(edge_t, e, n->edge_tree) {
+		if(i++ == j) {
+			candidate = e->reverse;
+			break;
+		}
+	}
+
+	if(candidate) {
+		*sa = &candidate->address;
+		*sock = rand() % listen_sockets;
+	}
+
+	/* Make sure we have a suitable socket for the chosen address */
+	if(listen_socket[*sock].sa.sa.sa_family != (*sa)->sa.sa_family) {
+		for(int i = 0; i < listen_sockets; i++) {
+			if(listen_socket[i].sa.sa.sa_family == (*sa)->sa.sa_family) {
+				*sock = i;
+				break;
+			}
+		}
+	}
+}
+
+static void choose_broadcast_address(const node_t *n, const sockaddr_t **sa, int *sock) {
+	static sockaddr_t broadcast_ipv4 = {
+		.in = {
+			.sin_family = AF_INET,
+			.sin_addr.s_addr = -1,
+		}
+	};
+
+	static sockaddr_t broadcast_ipv6 = {
+		.in6 = {
+			.sin6_family = AF_INET6,
+			.sin6_addr.s6_addr[0x0] = 0xff,
+			.sin6_addr.s6_addr[0x1] = 0x02,
+			.sin6_addr.s6_addr[0xf] = 0x01,
+		}
+	};
+
+	*sock = rand() % listen_sockets;
+
+	if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
+		if(localdiscovery_address.sa.sa_family == AF_INET6) {
+			localdiscovery_address.in6.sin6_port = n->prevedge->address.in.sin_port;
+			*sa = &localdiscovery_address;
+		} else {
+			broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
+			broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
+			*sa = &broadcast_ipv6;
+		}
+	} else {
+		if(localdiscovery_address.sa.sa_family == AF_INET) {
+			localdiscovery_address.in.sin_port = n->prevedge->address.in.sin_port;
+			*sa = &localdiscovery_address;
+		} else {
+			broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
+			*sa = &broadcast_ipv4;
+		}
+	}
+}
+
 static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 	vpn_packet_t pkt1, pkt2;
 	vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
@@ -462,15 +655,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 	/* Make sure we have a valid key */
 
 	if(!n->status.validkey) {
-		time_t now = time(NULL);
-
 		logger(DEBUG_TRAFFIC, LOG_INFO,
 				   "No valid key known yet for %s (%s), forwarding via TCP",
 				   n->name, n->hostname);
 
-		if(n->last_req_key + 10 <= now) {
+		if(n->last_req_key + 10 <= now.tv_sec) {
 			send_req_key(n);
-			n->last_req_key = now;
+			n->last_req_key = now.tv_sec;
 		}
 
 		send_tcppacket(n->nexthop->connection, origpkt);
@@ -512,11 +703,11 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
 	/* Encrypt the packet */
 
-	if(cipher_active(&n->outcipher)) {
+	if(cipher_active(n->outcipher)) {
 		outpkt = pkt[nextpkt++];
 		outlen = MAXSIZE;
 
-		if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+		if(!cipher_encrypt(n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
 			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
 			goto end;
 		}
@@ -527,95 +718,36 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
 	/* Add the message authentication code */
 
-	if(digest_active(&n->outdigest)) {
-		digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
-		inpkt->len += digest_length(&n->outdigest);
+	if(digest_active(n->outdigest)) {
+		if(!digest_create(n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len)) {
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
+			goto end;
+		}
+
+		inpkt->len += digest_length(n->outdigest);
 	}
 
 	/* Send the packet */
 
-	sockaddr_t *sa;
+	const sockaddr_t *sa;
 	int sock;
 
-	/* Overloaded use of priority field: -1 means local broadcast */
-
-	if(origpriority == -1 && n->prevedge) {
-		sockaddr_t broadcast;
-		broadcast.in.sin_family = AF_INET;
-		broadcast.in.sin_addr.s_addr = -1;
-		broadcast.in.sin_port = n->prevedge->address.in.sin_port;
-		sa = &broadcast;
-		sock = 0;
-	} else {
-		if(origpriority == -1)
-			origpriority = 0;
-
-		if(n->status.udp_confirmed) {
-			/* Address of this node is confirmed, so use it. */
-			sa = &n->address;
-			sock = n->sock;
-		} else {
-			/* Otherwise, go through the list of known addresses of
-			   this node. The first address we try is always the
-			   one in n->address; that could be set to the node's
-			   reflexive UDP address discovered during key
-			   exchange. The other known addresses are those found
-			   in edges to this node. */
-
-			static unsigned int i;
-			int j = 0;
-			edge_t *candidate = NULL;
-
-			if(i) {
-				for splay_each(edge_t, e, edge_weight_tree) {
-					if(e->to != n)
-						continue;
-					j++;
-					if(!candidate || j == i)
-						candidate = e;
-				}
-			}
-
-			if(!candidate) {
-				sa = &n->address;
-				sock = n->sock;
-			} else {
-				sa = &candidate->address;
-				sock = rand() % listen_sockets;
-			}
-
-			if(i++)
-				if(i > j)
-					i = 0;
-		}
-	}
-
-	/* Determine which socket we have to use */
-
-	if(sa->sa.sa_family != listen_socket[sock].sa.sa.sa_family)
-		for(sock = 0; sock < listen_sockets; sock++)
-			if(sa->sa.sa_family == listen_socket[sock].sa.sa.sa_family)
-				break;
-
-	if(sock >= listen_sockets)
-		sock = 0;
-
-	if(!n->status.udp_confirmed)
-		n->sock = sock;
+	if(n->status.broadcast)
+		choose_broadcast_address(n, &sa, &sock);
+	else
+		choose_udp_address(n, &sa, &sock);
 
 #if defined(SOL_IP) && defined(IP_TOS)
 	if(priorityinheritance && origpriority != priority
 	   && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
 		priority = origpriority;
 		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
-		if(setsockopt(listen_socket[n->sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
+		if(setsockopt(listen_socket[n->sock].udp.fd, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
 			logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
 	}
 #endif
 
-	socklen_t sl = SALEN(n->address.sa);
-
-	if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+	if(sendto(listen_socket[sock].udp.fd, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
 		if(sockmsgsize(sockerrno)) {
 			if(n->maxmtu >= origlen)
 				n->maxmtu = origlen - 1;
@@ -639,23 +771,25 @@ bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
 		b64encode(data, buf, len);
 		/* If no valid key is known yet, send the packets using ANS_KEY requests,
 		   to ensure we get to learn the reflexive UDP address. */
-		if(!to->status.validkey)
-			return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, myself->incompression);
-		else
+		if(!to->status.validkey) {
+			to->incompression = myself->incompression;
+			return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, to->incompression);
+		} else {
 			return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
+		}
 	}
 
 	/* Otherwise, send the packet via UDP */
 
-	struct sockaddr *sa;
-	socklen_t sl;
+	const sockaddr_t *sa;
 	int sock;
 
-	sa = &(to->address.sa);
-	sl = SALEN(to->address.sa);
-	sock = to->sock;
+	if(to->status.broadcast)
+		choose_broadcast_address(to, &sa, &sock);
+	else
+		choose_udp_address(to, &sa, &sock);
 
-	if(sendto(listen_socket[sock].udp, data, len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
+	if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
 		if(sockmsgsize(sockerrno)) {
 			if(to->maxmtu >= len)
 				to->maxmtu = len - 1;
@@ -711,11 +845,11 @@ bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t
 
 	int offset = (type & PKT_MAC) ? 0 : 14;
 	if(type & PKT_COMPRESSED) {
-		len = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
-		if(len < 0) {
+		length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
+		if(ulen < 0) {
 			return false;
 		} else {
-			inpkt.len = len + offset;
+			inpkt.len = ulen + offset;
 		}
 		if(inpkt.len > MAXSIZE)
 			abort();
@@ -758,7 +892,7 @@ void send_packet(node_t *n, vpn_packet_t *packet) {
 			 memcpy(packet->data, mymac.x, ETH_ALEN);
 		n->out_packets++;
 		n->out_bytes += packet->len;
-		devops.write(packet);
+		// TODO: send to application
 		return;
 	}
 
@@ -825,7 +959,7 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
 				break;
 
 			for splay_each(node_t, n, node_tree)
-				if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+				if(n->status.reachable && n != myself && ((n->via == myself && n->nexthop == n) || n->via == n))
 					send_packet(n, packet);
 			break;
 
@@ -838,14 +972,13 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
 	node_t *n = NULL;
 	bool hard = false;
 	static time_t last_hard_try = 0;
-	time_t now = time(NULL);
 
 	for splay_each(edge_t, e, edge_weight_tree) {
 		if(!e->to->status.reachable || e->to == myself)
 			continue;
 
 		if(sockaddrcmp_noport(from, &e->address)) {
-			if(last_hard_try == now)
+			if(last_hard_try == now.tv_sec)
 				continue;
 			hard = true;
 		}
@@ -858,13 +991,14 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
 	}
 
 	if(hard)
-		last_hard_try = now;
+		last_hard_try = now.tv_sec;
 
-	last_hard_try = now;
+	last_hard_try = now.tv_sec;
 	return n;
 }
 
-void handle_incoming_vpn_data(int sock, short events, void *data) {
+void handle_incoming_vpn_data(void *data, int flags) {
+	listen_socket_t *ls = data;
 	vpn_packet_t pkt;
 	char *hostname;
 	sockaddr_t from = {{0}};
@@ -872,7 +1006,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 	node_t *n;
 	int len;
 
-	len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+	len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
 	if(len <= 0 || len > MAXSIZE) {
 		if(!sockwouldblock(sockerrno))
@@ -900,19 +1034,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 			return;
 	}
 
-	n->sock = (intptr_t)data;
+	n->sock = ls - listen_socket;
 
 	receive_udppacket(n, &pkt);
 }
-
-void handle_device_data(int sock, short events, void *data) {
-	vpn_packet_t packet;
-
-	packet.priority = 0;
-
-	if(devops.read(&packet)) {
-		myself->in_packets++;
-		myself->in_bytes += packet.len;
-		route(myself, &packet);
-	}
-}