X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fnet_packet.c;h=c9a666377cecd4ec4fd05c7b4bf97eb827f39806;hp=544bbde775024a951d85525571406ca6ce0657c6;hb=ff306f0cdaedb50de1472e7c1fb55de922a6ca60;hpb=78fc59e994c764d072bf0045177f690a378d1308

diff --git a/src/net_packet.c b/src/net_packet.c
index 544bbde7..c9a66637 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,
-                  2000-2009 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2012 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
@@ -13,11 +15,9 @@
     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., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-    $Id$
+    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.
 */
 
 #include "system.h"
@@ -28,17 +28,22 @@
 #include <openssl/pem.h>
 #include <openssl/hmac.h>
 
+#ifdef HAVE_ZLIB
 #include <zlib.h>
+#endif
+
+#ifdef HAVE_LZO
 #include LZO1X_H
+#endif
 
-#include "avl_tree.h"
+#include "cipher.h"
 #include "conf.h"
 #include "connection.h"
+#include "crypto.h"
+#include "digest.h"
 #include "device.h"
 #include "ethernet.h"
-#include "event.h"
 #include "graph.h"
-#include "list.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"
@@ -48,240 +53,330 @@
 #include "utils.h"
 #include "xalloc.h"
 
-#ifdef WSAEMSGSIZE
-#define EMSGSIZE WSAEMSGSIZE
-#endif
-
 int keylifetime = 0;
-int keyexpires = 0;
-EVP_CIPHER_CTX packet_ctx;
+#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;
+
 #define MAX_SEQNO 1073741824
 
-void send_mtu_probe(node_t *n)
-{
+/* 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 three, with random sizes between the lower and
+   upper boundaries for the MTU thus far discovered.
+
+   In case local discovery is enabled, a fourth 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) {
+	node_t *n = data;
 	vpn_packet_t packet;
 	int len, i;
+	int timeout = 1;
 	
-	cp();
-
 	n->mtuprobes++;
-	n->mtuevent = NULL;
 
-	if(n->mtuprobes >= 10 && !n->minmtu) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, _("No response to MTU probes from %s (%s)"), n->name, n->hostname);
+	if(!n->status.reachable || !n->status.validkey) {
+		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;
 	}
 
-	for(i = 0; i < 3; i++) {
-		if(n->mtuprobes >= 30 || n->minmtu >= n->maxmtu) {
-			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);
-			return;
+	if(n->mtuprobes > 32) {
+		if(!n->minmtu) {
+			n->mtuprobes = 31;
+			timeout = pinginterval;
+			goto end;
 		}
 
-		len = n->minmtu + 1 + random() % (n->maxmtu - n->minmtu);
+		logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
+		n->mtuprobes = 1;
+		n->minmtu = 0;
+		n->maxmtu = MTU;
+	}
+
+	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)) {
+		if(n->minmtu > n->maxmtu)
+			n->minmtu = n->maxmtu;
+		else
+			n->maxmtu = n->minmtu;
+		n->mtu = n->minmtu;
+		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;
+	}
+
+	if(n->mtuprobes == 31) {
+		timeout = pinginterval;
+		goto end;
+	} else if(n->mtuprobes == 32) {
+		timeout = pingtimeout;
+	}
+
+	for(i = 0; i < 3 + localdiscovery; i++) {
+		if(n->maxmtu <= n->minmtu)
+			len = n->maxmtu;
+		else
+			len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+
 		if(len < 64)
 			len = 64;
 		
 		memset(packet.data, 0, 14);
-		RAND_pseudo_bytes(packet.data + 14, len - 14);
+		randomize(packet.data + 14, len - 14);
 		packet.len = len;
-		packet.priority = 0;
+		if(i >= 3 && n->mtuprobes <= 10)
+			packet.priority = -1;
+		else
+			packet.priority = 0;
 
-		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->mtuevent = new_event();
-	n->mtuevent->handler = (event_handler_t)send_mtu_probe;
-	n->mtuevent->data = n;
-	n->mtuevent->time = now + 1;
-	event_add(n->mtuevent);
+end:
+	event_add(&n->mtuevent, &(struct timeval){timeout, 0});
+}
+
+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);
 }
 
-void mtu_probe_h(node_t *n, vpn_packet_t *packet) {
-	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) {
+	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;
-		send_packet(n, packet);
+		send_udppacket(n, packet);
 	} else {
-		if(n->minmtu < packet->len)
-			n->minmtu = packet->len;
+		if(n->mtuprobes > 30) {
+			if(n->minmtu)
+				n->mtuprobes = 30;
+			else
+				n->mtuprobes = 1;
+		}
+
+		if(len > n->maxmtu)
+			len = n->maxmtu;
+		if(n->minmtu < len)
+			n->minmtu = len;
 	}
 }
 
-static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
-{
-	if(level == 10) {
+static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
+	if(level == 0) {
+		memcpy(dest, source, len);
+		return len;
+	} else if(level == 10) {
+#ifdef HAVE_LZO
 		lzo_uint lzolen = MAXSIZE;
 		lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem);
 		return lzolen;
+#else
+		return -1;
+#endif
 	} else if(level < 10) {
+#ifdef HAVE_ZLIB
 		unsigned long destlen = MAXSIZE;
 		if(compress2(dest, &destlen, source, len, level) == Z_OK)
 			return destlen;
 		else
+#endif
 			return -1;
 	} else {
+#ifdef HAVE_LZO
 		lzo_uint lzolen = MAXSIZE;
 		lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem);
 		return lzolen;
+#else
+		return -1;
+#endif
 	}
 	
 	return -1;
 }
 
-static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level)
-{
-	if(level > 9) {
+static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) {
+	if(level == 0) {
+		memcpy(dest, source, len);
+		return len;
+	} else if(level > 9) {
+#ifdef HAVE_LZO
 		lzo_uint lzolen = MAXSIZE;
 		if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK)
 			return lzolen;
 		else
+#endif
 			return -1;
-	} else {
+	}
+#ifdef HAVE_ZLIB
+	else {
 		unsigned long destlen = MAXSIZE;
 		if(uncompress(dest, &destlen, source, len) == Z_OK)
 			return destlen;
 		else
 			return -1;
 	}
-	
+#endif
+
 	return -1;
 }
 
 /* VPN packet I/O */
 
-static void receive_packet(node_t *n, vpn_packet_t *packet)
-{
-	cp();
-
-	ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"),
+static void receive_packet(node_t *n, vpn_packet_t *packet) {
+	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 void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
-{
+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))
+		return false;
+
+	return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
+}
+
+static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	vpn_packet_t pkt1, pkt2;
 	vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
 	int nextpkt = 0;
 	vpn_packet_t *outpkt = pkt[0];
-	int outlen, outpad;
-	unsigned char hmac[EVP_MAX_MD_SIZE];
-	int i;
+	size_t outlen;
+
+	if(n->status.sptps) {
+		sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
+		return;
+	}
 
-	cp();
+	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) + myself->maclength) {
-		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(myself->digest && myself->maclength) {
-		inpkt->len -= myself->maclength;
-		HMAC(myself->digest, myself->key, myself->keylength,
-			 (unsigned char *) &inpkt->seqno, inpkt->len, (unsigned char *)hmac, NULL);
-
-		if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
-			ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
-					   n->name, n->hostname);
+	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)) {
+			logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
 			return;
 		}
 	}
-
 	/* Decrypt the packet */
 
-	if(myself->cipher) {
+	if(cipher_active(&n->incipher)) {
 		outpkt = pkt[nextpkt++];
+		outlen = MAXSIZE;
 
-		if(!EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL)
-				|| !EVP_DecryptUpdate(&packet_ctx, (unsigned char *) &outpkt->seqno, &outlen,
-					(unsigned char *) &inpkt->seqno, inpkt->len)
-				|| !EVP_DecryptFinal_ex(&packet_ctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
-			ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
-						n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+		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 + outpad;
+		outpkt->len = outlen;
 		inpkt = outpkt;
 	}
 
 	/* Check the sequence number */
 
-	inpkt->len -= sizeof(inpkt->seqno);
+	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;
 			
 	if(n->received_seqno > MAX_SEQNO)
-		keyexpires = 0;
+		regenerate_key();
 
 	/* Decompress the packet */
 
-	if(myself->compression) {
+	length_t origlen = inpkt->len;
+
+	if(n->incompression) {
 		outpkt = pkt[nextpkt++];
 
-		if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
+		if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
 				  		 n->name, n->hostname);
 			return;
 		}
 
 		inpkt = outpkt;
+
+		origlen -= MTU/64 + 20;
 	}
 
 	inpkt->priority = 0;
 
-	if(n->connection)
-		n->connection->last_ping_time = now;
-
 	if(!inpkt->data[12] && !inpkt->data[13])
-		mtu_probe_h(n, inpkt);
+		mtu_probe_h(n, inpkt, origlen);
 	else
 		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;
 
-	cp();
-
 	outpkt.len = len;
 	if(c->options & OPTION_TCPONLY)
 		outpkt.priority = 0;
@@ -292,56 +387,112 @@ void receive_tcppacket(connection_t *c, char *buffer, int len)
 	receive_packet(c->node, &outpkt);
 }
 
-static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
-{
+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 < time(NULL)) {
+			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 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 outlen, outpad;
+	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) {
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
+		return;
+	}
 
-	cp();
+	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,
-				   _("No valid key known yet for %s (%s), forwarding via TCP"),
-				   n->name, n->hostname);
+		time_t now = time(NULL);
 
-		if(!n->status.waitingforkey)
-			send_req_key(n->nexthop->connection, myself, n);
+		logger(DEBUG_TRAFFIC, LOG_INFO,
+				   "No valid key known yet for %s (%s), forwarding via TCP",
+				   n->name, n->hostname);
 
-		n->status.waitingforkey = true;
+		if(n->last_req_key + 10 <= now) {
+			send_req_key(n);
+			n->last_req_key = now;
+		}
 
 		send_tcppacket(n->nexthop->connection, origpkt);
 
 		return;
 	}
 
-	if(!n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
-		ifdebug(TRAFFIC) logger(LOG_INFO,
-				_("No minimum MTU established yet for %s (%s), forwarding via TCP"),
-				n->name, n->hostname);
+	if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
+		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");
 
-		send_tcppacket(n->nexthop->connection, origpkt);
-	}
+		if(n != n->nexthop)
+			send_packet(n->nexthop, origpkt);
+		else
+			send_tcppacket(n->nexthop->connection, origpkt);
 
-	origlen = inpkt->len;
-	origpriority = inpkt->priority;
+		return;
+	}
 
 	/* Compress the packet */
 
-	if(n->compression) {
+	if(n->outcompression) {
 		outpkt = pkt[nextpkt++];
 
-		if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
+		if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
 				   n->name, n->hostname);
 			return;
 		}
@@ -352,98 +503,240 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt)
 	/* Add sequence number */
 
 	inpkt->seqno = htonl(++(n->sent_seqno));
-	inpkt->len += sizeof(inpkt->seqno);
+	inpkt->len += sizeof inpkt->seqno;
 
 	/* Encrypt the packet */
 
-	if(n->cipher) {
+	if(cipher_active(&n->outcipher)) {
 		outpkt = pkt[nextpkt++];
+		outlen = MAXSIZE;
 
-		if(!EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL)
-				|| !EVP_EncryptUpdate(&n->packet_ctx, (unsigned char *) &outpkt->seqno, &outlen,
-					(unsigned char *) &inpkt->seqno, inpkt->len)
-				|| !EVP_EncryptFinal_ex(&n->packet_ctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
-			ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
-						n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+		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;
 		}
 
-		outpkt->len = outlen + outpad;
+		outpkt->len = outlen;
 		inpkt = outpkt;
 	}
 
 	/* Add the message authentication code */
 
-	if(n->digest && n->maclength) {
-		HMAC(n->digest, n->key, n->keylength, (unsigned char *) &inpkt->seqno,
-			 inpkt->len, (unsigned char *) &inpkt->seqno + inpkt->len, NULL);
-		inpkt->len += n->maclength;
+	if(digest_active(&n->outdigest)) {
+		digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
+		inpkt->len += digest_length(&n->outdigest);
 	}
 
 	/* Determine which socket we have to use */
 
-	for(sock = 0; sock < listen_sockets; sock++)
-		if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
-			break;
-
-	if(sock >= listen_sockets)
-		sock = 0;				/* If none is available, just use the first and hope for the best. */
+	if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) {
+		for(int sock = 0; sock < listen_sockets; sock++) {
+			if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) {
+				n->sock = sock;
+				break;
+			}
+		}
+	}
 
 	/* Send the packet */
 
+	struct sockaddr *sa;
+	socklen_t sl;
+	int sock;
+
+	/* Overloaded use of priority field: -1 means local broadcast */
+
+	if(origpriority == -1 && n->prevedge) {
+		struct sockaddr_in in;
+		in.sin_family = AF_INET;
+		in.sin_addr.s_addr = -1;
+		in.sin_port = n->prevedge->address.in.sin_port;
+		sa = (struct sockaddr *)&in;
+		sl = sizeof in;
+		sock = 0;
+	} else {
+		if(origpriority == -1)
+			origpriority = 0;
+
+		sa = &(n->address.sa);
+		sl = SALEN(n->address.sa);
+		sock = n->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, 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) {
-		if(errno == EMSGSIZE) {
+	if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 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, strerror(errno));
+			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;
+
+	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(!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
+			return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, type >= SPTPS_HANDSHAKE ? REQ_SPTPS : REQ_PACKET, buf);
+	}
+
+	/* Send the packet */
+
+	struct sockaddr *sa;
+	socklen_t sl;
+	int sock;
+
+	sa = &(to->address.sa);
+	sl = SALEN(to->address.sa);
+	sock = to->sock;
+
+	if(sendto(listen_socket[sock].udp, data, len, 0, sa, sl) < 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) {
+		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) {
+		len = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
+		if(len < 0) {
+			return false;
+		} else {
+			inpkt.len = len + 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;
 
-	cp();
-
 	if(n == myself) {
 		if(overwrite_mac)
 			 memcpy(packet->data, mymac.x, ETH_ALEN);
-		write_packet(packet);
+		n->out_packets++;
+		n->out_bytes += packet->len;
+		devops.write(packet);
 		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)) {
@@ -455,55 +748,136 @@ 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)
-{
-	avl_node_t *node;
-	connection_t *c;
+void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
+	// Always give ourself a copy of the packet.
+	if(from != myself)
+		send_packet(myself, packet);
 
-	cp();
+	// In TunnelServer mode, do not forward broadcast packets.
+        // The MST might not be valid and create loops.
+	if(tunnelserver || broadcast_mode == BMODE_NONE)
+		return;
 
-	ifdebug(TRAFFIC) logger(LOG_INFO, _("Broadcasting packet of %d bytes from %s (%s)"),
+	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_node_t *node = connection_list->head, *next; node; node = next) {
+				next = node->next;
+				connection_t *c = node->data;
+
+				if(c->status.active && c->status.mst && c != from->nexthop->connection)
+					send_packet(c->node, packet);
+			}
+			break;
+
+		// 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_node_t *node = node_tree->head; node; node = node->next) {
+				node_t *n = node->data;
 
-		if(c->status.active && c->status.mst && c != from->nexthop->connection)
-			send_packet(c->node, packet);
+				if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+					send_packet(n, packet);
+			}
+			break;
+
+		default:
+			break;
 	}
 }
 
-void handle_incoming_vpn_data(int sock)
-{
+static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
+	splay_node_t *node;
+	edge_t *e;
+	node_t *n = NULL;
+	bool hard = false;
+	static time_t last_hard_try = 0;
+	time_t now = time(NULL);
+
+	for(node = edge_weight_tree->head; node; node = node->next) {
+		e = node->data;
+
+		if(!e->to->status.reachable || e->to == myself)
+			continue;
+
+		if(sockaddrcmp_noport(from, &e->address)) {
+			if(last_hard_try == now)
+				continue;
+			hard = true;
+		}
+
+		if(!try_mac(e->to, pkt))
+			continue;
+
+		n = e->to;
+		break;
+	}
+
+	if(hard)
+		last_hard_try = now;
+
+	last_hard_try = now;
+	return n;
+}
+
+void handle_incoming_vpn_data(int sock, short events, void *data) {
 	vpn_packet_t pkt;
 	char *hostname;
-	sockaddr_t from;
-	socklen_t fromlen = sizeof(from);
+	sockaddr_t from = {{0}};
+	socklen_t fromlen = sizeof from;
 	node_t *n;
+	int len;
 
-	cp();
+	len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-	pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
-
-	if(pkt.len < 0) {
-		logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
+	if(len <= 0 || len > MAXSIZE) {
+		if(!sockwouldblock(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. */
 
 	n = lookup_node_udp(&from);
 
 	if(!n) {
-		hostname = sockaddr2hostname(&from);
-		logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
-			   hostname);
-		free(hostname);
-		return;
+		n = try_harder(&from, &pkt);
+		if(n)
+			update_node_udp(n, &from);
+		else if(debug_level >= DEBUG_PROTOCOL) {
+			hostname = sockaddr2hostname(&from);
+			logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
+			free(hostname);
+			return;
+		}
+		else
+			return;
 	}
 
+	n->sock = (intptr_t)data;
+
 	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);
+	}
+}