X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fnet_packet.c;h=30ad3e504c3cf56c68650d9897c2c4551230db28;hb=b3b89e46b1b84fa6cf1726fabe9e9c7bb0d3d831;hp=fc09957d0ec386c7eb6668586ef74b4f9c5e2ec5;hpb=103543aa2c15d9f1e2aa313a2e593a7524cce484;p=meshlink

diff --git a/src/net_packet.c b/src/net_packet.c
index fc09957d..30ad3e50 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -1,7 +1,9 @@
 /*
     net_packet.c -- Handles in- and outgoing VPN packets
     Copyright (C) 1998-2005 Ivo Timmermans,
-                  2000-2010 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>
 
     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
@@ -20,12 +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
@@ -34,65 +30,79 @@
 #include LZO1X_H
 #endif
 
-#include "splay_tree.h"
 #include "cipher.h"
 #include "conf.h"
 #include "connection.h"
 #include "crypto.h"
 #include "digest.h"
-#include "device.h"
 #include "ethernet.h"
 #include "graph.h"
-#include "list.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"
 
 int keylifetime = 0;
-int keyexpires = 0;
 #ifdef HAVE_LZO
 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
 #endif
 
 static void send_udppacket(node_t *, vpn_packet_t *);
 
+unsigned replaywin = 16;
+bool localdiscovery = false;
+sockaddr_t localdiscovery_address;
+
 #define MAX_SEQNO 1073741824
 
-// mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
-// mtuprobes ==    31: sleep pinginterval seconds
-// mtuprobes ==    32: send 1 burst, sleep pingtimeout second
-// mtuprobes ==    33: no response from other side, restart PMTU discovery process
+/* mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
+   mtuprobes ==    31: sleep pinginterval seconds
+   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 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, 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;
-	vpn_packet_t packet;
-	int len, i;
 	int timeout = 1;
-	
+
 	n->mtuprobes++;
 
 	if(!n->status.reachable || !n->status.validkey) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
 		n->mtuprobes = 0;
 		return;
 	}
 
 	if(n->mtuprobes > 32) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+		if(!n->minmtu) {
+			n->mtuprobes = 31;
+			timeout = pinginterval;
+			goto end;
+		}
+
+		logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+		n->status.udp_confirmed = false;
 		n->mtuprobes = 1;
 		n->minmtu = 0;
 		n->maxmtu = MTU;
 	}
 
-	if(n->mtuprobes >= 10 && !n->minmtu) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
-		n->mtuprobes = 0;
-		return;
+	if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
+		logger(DEBUG_TRAFFIC, LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
+		n->mtuprobes = 31;
 	}
 
 	if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
@@ -101,7 +111,7 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
 		else
 			n->maxmtu = n->minmtu;
 		n->mtu = n->minmtu;
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
 		n->mtuprobes = 31;
 	}
 
@@ -112,48 +122,156 @@ static void send_mtu_probe_handler(int fd, short events, void *data) {
 		timeout = pingtimeout;
 	}
 
-	for(i = 0; i < 3; i++) {
-		if(n->maxmtu <= n->minmtu)
+	for(int i = 0; i < 4 + localdiscovery; i++) {
+		int len;
+
+		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;
-		
+
+		vpn_packet_t packet;
 		memset(packet.data, 0, 14);
 		randomize(packet.data + 14, len - 14);
 		packet.len = len;
 		packet.priority = 0;
+		n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
 
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
+		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);
 }
 
-void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
-	ifdebug(TRAFFIC) logger(LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
-
+static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 	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 {
-		if(len > n->maxmtu)
-			len = n->maxmtu;
-		if(n->minmtu < len)
-			n->minmtu = len;
-		if(n->mtuprobes > 30)
-			n->mtuprobes = 30;
+		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 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);
+		}
 	}
 }
 
@@ -186,7 +304,7 @@ static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t l
 		return -1;
 #endif
 	}
-	
+
 	return -1;
 }
 
@@ -219,17 +337,23 @@ static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t
 /* VPN packet I/O */
 
 static void receive_packet(node_t *n, vpn_packet_t *packet) {
-	ifdebug(TRAFFIC) logger(LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
+	logger(DEBUG_TRAFFIC, LOG_DEBUG, "Received packet of %d bytes from %s (%s)",
 			   packet->len, n->name, n->hostname);
 
+	n->in_packets++;
+	n->in_bytes += packet->len;
+
 	route(n, packet);
 }
 
 static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
-	if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
+	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))
 		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) {
@@ -238,42 +362,54 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	int nextpkt = 0;
 	vpn_packet_t *outpkt = pkt[0];
 	size_t outlen;
-	int i;
 
-	if(!cipher_active(&n->incipher)) {
-		ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
-					n->name, n->hostname);
+	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);
 		return;
 	}
 
 	/* Check packet length */
 
-	if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
-		ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got too short packet from %s (%s)",
+	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;
 	}
 
 	/* 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)) {
-			ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
+	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)) {
-			ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
+		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;
 		}
-		
+
 		outpkt->len = outlen;
 		inpkt = outpkt;
 	}
@@ -283,29 +419,38 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	inpkt->len -= sizeof inpkt->seqno;
 	inpkt->seqno = ntohl(inpkt->seqno);
 
-	if(inpkt->seqno != n->received_seqno + 1) {
-		if(inpkt->seqno >= n->received_seqno + sizeof n->late * 8) {
-			logger(LOG_WARNING, "Lost %d packets from %s (%s)",
-					   inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
-			
-			memset(n->late, 0, sizeof n->late);
-		} else if (inpkt->seqno <= n->received_seqno) {
-			if((n->received_seqno >= sizeof n->late * 8 && inpkt->seqno <= n->received_seqno - sizeof n->late * 8) || !(n->late[(inpkt->seqno / 8) % sizeof n->late] & (1 << inpkt->seqno % 8))) {
-				logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
-					   n->name, n->hostname, inpkt->seqno, n->received_seqno);
-				return;
+	if(replaywin) {
+		if(inpkt->seqno != n->received_seqno + 1) {
+			if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
+				if(n->farfuture++ < replaywin >> 2) {
+					logger(DEBUG_ALWAYS, LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
+						n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
+					return;
+				}
+				logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
+						inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
+				memset(n->late, 0, replaywin);
+			} else if (inpkt->seqno <= n->received_seqno) {
+				if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
+					logger(DEBUG_ALWAYS, LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
+						n->name, n->hostname, inpkt->seqno, n->received_seqno);
+					return;
+				}
+			} else {
+				for(int i = n->received_seqno + 1; i < inpkt->seqno; i++)
+					n->late[(i / 8) % replaywin] |= 1 << i % 8;
 			}
-		} else {
-			for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
-				n->late[(i / 8) % sizeof n->late] |= 1 << i % 8;
 		}
+
+		n->farfuture = 0;
+		n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
 	}
-	
-	n->late[(inpkt->seqno / 8) % sizeof n->late] &= ~(1 << inpkt->seqno % 8);
 
 	if(inpkt->seqno > n->received_seqno)
 		n->received_seqno = inpkt->seqno;
-			
+
+	n->received++;
+
 	if(n->received_seqno > MAX_SEQNO)
 		regenerate_key();
 
@@ -317,8 +462,8 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 		outpkt = pkt[nextpkt++];
 
 		if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, "Error while uncompressing packet from %s (%s)",
-				  		 n->name, n->hostname);
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
+						 n->name, n->hostname);
 			return;
 		}
 
@@ -335,9 +480,12 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 		receive_packet(n, inpkt);
 }
 
-void receive_tcppacket(connection_t *c, char *buffer, int len) {
+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;
@@ -348,33 +496,172 @@ void receive_tcppacket(connection_t *c, char *buffer, int len) {
 	receive_packet(c->node, &outpkt);
 }
 
+static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
+	if(!n->status.validkey) {
+		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 < 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;
+			send_req_key(n);
+		}
+		return;
+	}
+
+	uint8_t type = 0;
+	int offset = 0;
+
+	if(!(origpkt->data[12] | origpkt->data[13])) {
+		sptps_send_record(&n->sptps, PKT_PROBE, (char *)origpkt->data, origpkt->len);
+		return;
+	}
+
+	if(routing_mode == RMODE_ROUTER)
+		offset = 14;
+	else
+		type = PKT_MAC;
+
+	if(origpkt->len < offset)
+		return;
+
+	vpn_packet_t outpkt;
+
+	if(n->outcompression) {
+		int len = compress_packet(outpkt.data + offset, origpkt->data + offset, origpkt->len - offset, n->outcompression);
+		if(len < 0) {
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)", n->name, n->hostname);
+		} else if(len < origpkt->len - offset) {
+			outpkt.len = len + offset;
+			origpkt = &outpkt;
+			type |= PKT_COMPRESSED;
+		}
+	}
+
+	sptps_send_record(&n->sptps, type, (char *)origpkt->data + offset, origpkt->len - offset);
+	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 };
 	vpn_packet_t *inpkt = origpkt;
 	int nextpkt = 0;
 	vpn_packet_t *outpkt;
-	int origlen;
+	int origlen = origpkt->len;
 	size_t outlen;
+#if defined(SOL_IP) && defined(IP_TOS)
 	static int priority = 0;
-	int origpriority;
-	int sock;
+#endif
+	int origpriority = origpkt->priority;
 
 	if(!n->status.reachable) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
 		return;
 	}
 
+	if(n->status.sptps)
+		return send_sptps_packet(n, origpkt);
+
 	/* Make sure we have a valid key */
 
 	if(!n->status.validkey) {
-		ifdebug(TRAFFIC) logger(LOG_INFO,
+		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);
@@ -383,7 +670,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 	}
 
 	if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
-		ifdebug(TRAFFIC) logger(LOG_INFO,
+		logger(DEBUG_TRAFFIC, LOG_INFO,
 				"Packet for %s (%s) larger than minimum MTU, forwarding via %s",
 				n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
 
@@ -395,16 +682,13 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 		return;
 	}
 
-	origlen = inpkt->len;
-	origpriority = inpkt->priority;
-
 	/* Compress the packet */
 
 	if(n->outcompression) {
 		outpkt = pkt[nextpkt++];
 
 		if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, "Error while compressing packet to %s (%s)",
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
 				   n->name, n->hostname);
 			return;
 		}
@@ -419,12 +703,12 @@ 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)) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
+		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;
 		}
 
@@ -434,72 +718,205 @@ 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;
+		}
 
-	/* Determine which socket we have to use */
+		inpkt->len += digest_length(n->outdigest);
+	}
 
-	for(sock = 0; sock < listen_sockets; sock++)
-		if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
-			break;
+	/* Send the packet */
 
-	if(sock >= listen_sockets)
-		sock = 0;				/* If none is available, just use the first and hope for the best. */
+	const sockaddr_t *sa;
+	int sock;
 
-	/* Send the packet */
+	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[sock].sa.sa.sa_family == AF_INET) {
+	   && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
 		priority = origpriority;
-		ifdebug(TRAFFIC) logger(LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
-		if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof priority))	/* SO_PRIORITY doesn't seem to work */
-			logger(LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
+		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
+		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
 
-	if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa)) < 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;
 			if(n->mtu >= origlen)
 				n->mtu = origlen - 1;
 		} else
-			logger(LOG_ERR, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
+			logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
 	}
 
 end:
 	origpkt->len = origlen;
 }
 
+bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
+	node_t *to = handle;
+
+	/* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
+
+	if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && len > to->minmtu)) {
+		char buf[len * 4 / 3 + 5];
+		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) {
+			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 */
+
+	const sockaddr_t *sa;
+	int sock;
+
+	if(to->status.broadcast)
+		choose_broadcast_address(to, &sa, &sock);
+	else
+		choose_udp_address(to, &sa, &sock);
+
+	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;
+			if(to->mtu >= len)
+				to->mtu = len - 1;
+		} else {
+			logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", to->name, to->hostname, sockstrerror(sockerrno));
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
+	node_t *from = handle;
+
+	if(type == SPTPS_HANDSHAKE) {
+		if(!from->status.validkey) {
+			from->status.validkey = true;
+			from->status.waitingforkey = false;
+			logger(DEBUG_META, LOG_INFO, "SPTPS key exchange with %s (%s) succesful", from->name, from->hostname);
+		}
+		return true;
+	}
+
+	if(len > MTU) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Packet from %s (%s) larger than maximum supported size (%d > %d)", from->name, from->hostname, len, MTU);
+		return false;
+	}
+
+	vpn_packet_t inpkt;
+
+	if(type == PKT_PROBE) {
+		inpkt.len = len;
+		memcpy(inpkt.data, data, len);
+		mtu_probe_h(from, &inpkt, len);
+		return true;
+	}
+
+	if(type & ~(PKT_COMPRESSED | PKT_MAC)) {
+		logger(DEBUG_ALWAYS, LOG_ERR, "Unexpected SPTPS record type %d len %d from %s (%s)", type, len, from->name, from->hostname);
+		return false;
+	}
+
+	/* Check if we have the headers we need */
+	if(routing_mode != RMODE_ROUTER && !(type & PKT_MAC)) {
+		logger(DEBUG_TRAFFIC, LOG_ERR, "Received packet from %s (%s) without MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
+		return false;
+	} else if(routing_mode == RMODE_ROUTER && (type & PKT_MAC)) {
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Received packet from %s (%s) with MAC header (maybe Mode is not set correctly)", from->name, from->hostname);
+	}
+
+	int offset = (type & PKT_MAC) ? 0 : 14;
+	if(type & PKT_COMPRESSED) {
+		length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
+		if(ulen < 0) {
+			return false;
+		} else {
+			inpkt.len = ulen + offset;
+		}
+		if(inpkt.len > MAXSIZE)
+			abort();
+	} else {
+		memcpy(inpkt.data + offset, data, len);
+		inpkt.len = len + offset;
+	}
+
+	/* Generate the Ethernet packet type if necessary */
+	if(offset) {
+		switch(inpkt.data[14] >> 4) {
+			case 4:
+				inpkt.data[12] = 0x08;
+				inpkt.data[13] = 0x00;
+				break;
+			case 6:
+				inpkt.data[12] = 0x86;
+				inpkt.data[13] = 0xDD;
+				break;
+			default:
+				logger(DEBUG_TRAFFIC, LOG_ERR,
+						   "Unknown IP version %d while reading packet from %s (%s)",
+						   inpkt.data[14] >> 4, from->name, from->hostname);
+				return false;
+		}
+	}
+
+	receive_packet(from, &inpkt);
+	return true;
+}
+
 /*
   send a packet to the given vpn ip.
 */
-void send_packet(const node_t *n, vpn_packet_t *packet) {
+void send_packet(node_t *n, vpn_packet_t *packet) {
 	node_t *via;
 
 	if(n == myself) {
 		if(overwrite_mac)
 			 memcpy(packet->data, mymac.x, ETH_ALEN);
-		write_packet(packet);
+		n->out_packets++;
+		n->out_bytes += packet->len;
+		// TODO: send to application
 		return;
 	}
 
-	ifdebug(TRAFFIC) logger(LOG_ERR, "Sending packet of %d bytes to %s (%s)",
+	logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)",
 			   packet->len, n->name, n->hostname);
 
 	if(!n->status.reachable) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Node %s (%s) is not reachable",
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable",
 				   n->name, n->hostname);
 		return;
 	}
 
+	n->out_packets++;
+	n->out_bytes += packet->len;
+
+	if(n->status.sptps) {
+		send_sptps_packet(n, packet);
+		return;
+	}
+
 	via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
 
 	if(via != n)
-		ifdebug(TRAFFIC) logger(LOG_INFO, "Sending packet to %s via %s (%s)",
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)",
 			   n->name, via->name, n->via->hostname);
 
 	if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
@@ -512,74 +929,94 @@ void send_packet(const node_t *n, vpn_packet_t *packet) {
 /* Broadcast a packet using the minimum spanning tree */
 
 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
-	splay_node_t *node;
-	connection_t *c;
+	// Always give ourself a copy of the packet.
+	if(from != myself)
+		send_packet(myself, packet);
 
-	ifdebug(TRAFFIC) logger(LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
+	// In TunnelServer mode, do not forward broadcast packets.
+	// The MST might not be valid and create loops.
+	if(tunnelserver || broadcast_mode == BMODE_NONE)
+		return;
+
+	logger(DEBUG_TRAFFIC, LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
 			   packet->len, from->name, from->hostname);
 
-	if(from != myself) {
-		send_packet(myself, packet);
+	switch(broadcast_mode) {
+		// In MST mode, broadcast packets travel via the Minimum Spanning Tree.
+		// This guarantees all nodes receive the broadcast packet, and
+		// usually distributes the sending of broadcast packets over all nodes.
+		case BMODE_MST:
+			for list_each(connection_t, c, connection_list)
+				if(c->status.active && c->status.mst && c != from->nexthop->connection)
+					send_packet(c->node, packet);
+			break;
 
-		// In TunnelServer mode, do not forward broadcast packets.
-                // The MST might not be valid and create loops.
-		if(tunnelserver)
-			return;
-	}
+		// In direct mode, we send copies to each node we know of.
+		// However, this only reaches nodes that can be reached in a single hop.
+		// We don't have enough information to forward broadcast packets in this case.
+		case BMODE_DIRECT:
+			if(from != myself)
+				break;
 
-	for(node = connection_tree->head; node; node = node->next) {
-		c = node->data;
+			for splay_each(node_t, n, node_tree)
+				if(n->status.reachable && n != myself && ((n->via == myself && n->nexthop == n) || n->via == n))
+					send_packet(n, packet);
+			break;
 
-		if(c->status.active && c->status.mst && c != from->nexthop->connection)
-			send_packet(c->node, packet);
+		default:
+			break;
 	}
 }
 
 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
-	splay_node_t *node;
-	node_t *n, *found = NULL;
+	node_t *n = NULL;
+	bool hard = false;
 	static time_t last_hard_try = 0;
-	time_t now = time(NULL);
 
-	if(last_hard_try == now)
-		return NULL;
-	else
-		last_hard_try = now;
+	for splay_each(edge_t, e, edge_weight_tree) {
+		if(!e->to->status.reachable || e->to == myself)
+			continue;
 
-	for(node = node_tree->head; node; node = node->next) {
-		n = node->data;
+		if(sockaddrcmp_noport(from, &e->address)) {
+			if(last_hard_try == now.tv_sec)
+				continue;
+			hard = true;
+		}
 
-		if(n == myself || !n->status.reachable || !digest_active(&n->indigest))
+		if(!try_mac(e->to, pkt))
 			continue;
 
-		if(try_mac(n, pkt)) {
-			found = n;
-			break;
-		}
+		n = e->to;
+		break;
 	}
 
-	return found;
+	if(hard)
+		last_hard_try = now.tv_sec;
+
+	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;
+	sockaddr_t from = {{0}};
 	socklen_t fromlen = sizeof from;
 	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))
-			logger(LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
+			logger(DEBUG_ALWAYS, LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
 		return;
 	}
 
 	pkt.len = len;
 
-	sockaddrunmap(&from);		/* Some braindead IPv6 implementations do stupid things. */
+	sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
 
 	n = lookup_node_udp(&from);
 
@@ -587,9 +1024,9 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 		n = try_harder(&from, &pkt);
 		if(n)
 			update_node_udp(n, &from);
-		else ifdebug(PROTOCOL) {
+		else if(debug_level >= DEBUG_PROTOCOL) {
 			hostname = sockaddr2hostname(&from);
-			logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
+			logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
 			free(hostname);
 			return;
 		}
@@ -597,12 +1034,7 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 			return;
 	}
 
-	receive_udppacket(n, &pkt);
-}
-
-void handle_device_data(int sock, short events, void *data) {
-	vpn_packet_t packet;
+	n->sock = ls - listen_socket;
 
-	if(read_packet(&packet))
-		route(myself, &packet);
+	receive_udppacket(n, &pkt);
 }