X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fnet_packet.c;h=cbdc15cfebc98ea77156017b65db2c4beb3d472a;hb=19be9cf7150858311f7898fa3fb525d692d02f64;hp=e430b6c96a5efcd948f53bb019d71fff1f9b82c2;hpb=7ea85043ac1fb2096baea44f6b0af27ac0d0b2cf;p=meshlink

diff --git a/src/net_packet.c b/src/net_packet.c
index e430b6c9..cbdc15cf 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
@@ -20,8 +22,19 @@
 
 #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
+
+#ifdef HAVE_LZO
 #include LZO1X_H
+#endif
 
 #include "splay_tree.h"
 #include "cipher.h"
@@ -32,7 +45,6 @@
 #include "device.h"
 #include "ethernet.h"
 #include "graph.h"
-#include "list.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"
@@ -42,57 +54,103 @@
 #include "utils.h"
 #include "xalloc.h"
 
-#ifdef WSAEMSGSIZE
-#define EMSGSIZE WSAEMSGSIZE
-#endif
-
 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;
+
 #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
+
+   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;
 	
 	n->mtuprobes++;
 
-	if(!n->status.reachable) {
-		logger(LOG_DEBUG, "Trying to send MTU probe to unreachable node %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;
 	}
 
-	if(n->mtuprobes >= 10 && !n->minmtu) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
-		return;
+	if(n->mtuprobes > 32) {
+		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->mtuprobes = 1;
+		n->minmtu = 0;
+		n->maxmtu = MTU;
 	}
 
-	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 >= 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);
 
-		len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
 		if(len < 64)
 			len = 64;
 		
 		memset(packet.data, 0, 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);
 	}
 
-	event_add(&n->mtuevent, &(struct timeval){1, 0});
+end:
+	event_add(&n->mtuevent, &(struct timeval){timeout, 0});
 }
 
 void send_mtu_probe(node_t *n) {
@@ -101,62 +159,95 @@ void send_mtu_probe(node_t *n) {
 	send_mtu_probe_handler(0, 0, 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) {
+	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->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) {
+	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) {
+	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) {
-	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);
 }
 
@@ -164,7 +255,7 @@ 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))
 		return false;
 
-	return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len);
+	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) {
@@ -173,10 +264,9 @@ 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",
+		logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
 					n->name, n->hostname);
 		return;
 	}
@@ -184,18 +274,20 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 	/* 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)",
+		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) && !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);
-		return;
+	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(cipher_active(&n->incipher)) {
@@ -203,7 +295,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 		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);
+			logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
 			return;
 		}
 		
@@ -216,25 +308,32 @@ 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;
@@ -250,7 +349,7 @@ 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)",
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
 				  		 n->name, n->hostname);
 			return;
 		}
@@ -268,7 +367,7 @@ 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;
 
 	outpkt.len = len;
@@ -287,28 +386,31 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 	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;
+	int origpriority = origpkt->priority;
+#endif
 
 	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;
 	}
 
 	/* Make sure we have a valid key */
 
 	if(!n->status.validkey) {
-		ifdebug(TRAFFIC) logger(LOG_INFO,
+		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->status.waitingforkey)
+		if(n->last_req_key + 10 <= now) {
 			send_req_key(n);
-
-		n->status.waitingforkey = true;
+			n->last_req_key = now;
+		}
 
 		send_tcppacket(n->nexthop->connection, origpkt);
 
@@ -316,25 +418,25 @@ 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,
-				"Packet for %s (%s) larger than minimum MTU, forwarding via TCP",
-				n->name, n->hostname);
+		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);
 
 		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;
 		}
@@ -354,7 +456,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 		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);
+			logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
 			goto end;
 		}
 
@@ -371,33 +473,58 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
 
 	/* 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:
@@ -407,29 +534,34 @@ end:
 /*
   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;
+		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;
+
 	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)) {
@@ -444,24 +576,50 @@ void send_packet(const node_t *n, vpn_packet_t *packet) {
 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
 	splay_node_t *node;
 	connection_t *c;
+	node_t *n;
+
+	// Always give ourself a copy of the packet.
+	if(from != myself)
+		send_packet(myself, packet);
+
+	// 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(node = connection_tree->head; node; node = node->next) {
+				c = node->data;
 
-		// In TunnelServer mode, do not forward broadcast packets.
-                // The MST might not be valid and create loops.
-		if(tunnelserver)
-			return;
-	}
+				if(c->status.active && c->status.mst && c != from->nexthop->connection)
+					send_packet(c->node, packet);
+			}
+			break;
 
-	for(node = connection_tree->head; node; node = node->next) {
-		c = node->data;
+		// 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;
 
-		if(c->status.active && c->status.mst && c != from->nexthop->connection)
-			send_packet(c->node, packet);
+			for(node = node_udp_tree->head; node; node = node->next) {
+				n = node->data;
+
+				if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+					send_packet(n, packet);
+			}
+			break;
+
+		default:
+			break;
 	}
 }
 
@@ -469,15 +627,21 @@ 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(sockaddrcmp_noport(from, &e->address))
+		if(e->to == myself)
 			continue;
 
-		if(!n)
-			n = e->to;
+		if(sockaddrcmp_noport(from, &e->address)) {
+			if(last_hard_try == now)
+				continue;
+			hard = true;
+		}
 
 		if(!try_mac(e->to, pkt))
 			continue;
@@ -486,6 +650,10 @@ static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
 		break;
 	}
 
+	if(hard)
+		last_hard_try = now;
+
+	last_hard_try = now;
 	return n;
 }
 
@@ -495,15 +663,18 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 	sockaddr_t from;
 	socklen_t fromlen = sizeof from;
 	node_t *n;
+	int len;
 
-	pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+	len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-	if(pkt.len < 0) {
-		if(errno != EAGAIN && errno != EINTR)
-			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);
@@ -512,9 +683,9 @@ 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;
 		}
@@ -522,12 +693,19 @@ void handle_incoming_vpn_data(int sock, short events, void *data) {
 			return;
 	}
 
+	n->sock = (intptr_t)data;
+
 	receive_udppacket(n, &pkt);
 }
 
 void handle_device_data(int sock, short events, void *data) {
 	vpn_packet_t packet;
 
-	if(read_packet(&packet))
+	packet.priority = 0;
+
+	if(devops.read(&packet)) {
+		myself->in_packets++;
+		myself->in_bytes += packet.len;
 		route(myself, &packet);
+	}
 }