X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=fc08f5f7aae7c8cb3a1a87bb3c96821677e1a672;hp=d7c4c872fe27fed160af90458ea403ecd66e4387;hb=d6b45d005530496e48325a6174ecdd889a17bfc1;hpb=a8a3a2c8ceb19bcb6c2c3ef0647c94d7d0624b7a

diff --git a/src/route.c b/src/route.c
index d7c4c872..fc08f5f7 100644
--- a/src/route.c
+++ b/src/route.c
@@ -1,7 +1,7 @@
 /*
     route.c -- routing
     Copyright (C) 2000-2005 Ivo Timmermans,
-                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2018 Guus Sliepen <guus@tinc-vpn.org>
 
     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
@@ -59,6 +59,7 @@ static const size_t opt_size = sizeof(struct nd_opt_hdr);
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #endif
 
+volatile int dummy;
 static timeout_t age_subnets_timeout;
 
 /* RFC 1071 */
@@ -72,11 +73,18 @@ static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
 		len -= 2;
 	}
 
-	if(len)
+	if(len) {
 		checksum += *(uint8_t *)p;
+	}
 
-	while(checksum >> 16)
+	while(checksum >> 16) {
 		checksum = (checksum & 0xFFFF) + (checksum >> 16);
+	}
+
+	// Work around a compiler optimization bug.
+	if(checksum) {
+		dummy = 1;
+	}
 
 	return ~checksum;
 }
@@ -86,8 +94,9 @@ static bool ratelimit(int frequency) {
 	static int count = 0;
 
 	if(lasttime == now.tv_sec) {
-		if(count >= frequency)
+		if(count >= frequency) {
 			return true;
+		}
 	} else {
 		lasttime = now.tv_sec;
 		count = 0;
@@ -101,17 +110,298 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 	if(packet->len < length) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Got too short packet from %s (%s)", source->name, source->hostname);
 		return false;
-	} else
+	} else {
+		return true;
+	}
+}
+
+static void swap_mac_addresses(vpn_packet_t *packet) {
+	mac_t tmp;
+	memcpy(&tmp, &DATA(packet)[0], sizeof(tmp));
+	memcpy(&DATA(packet)[0], &DATA(packet)[6], sizeof(tmp));
+	memcpy(&DATA(packet)[6], &tmp, sizeof(tmp));
+}
+
+/* RFC 792 */
+
+static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
+	struct ip ip = {0};
+	struct icmp icmp = {0};
+
+	struct in_addr ip_src;
+	struct in_addr ip_dst;
+	uint32_t oldlen;
+
+	if(ratelimit(3)) {
+		return;
+	}
+
+	/* Swap Ethernet source and destination addresses */
+
+	swap_mac_addresses(packet);
+
+	/* Copy headers from packet into properly aligned structs on the stack */
+
+	memcpy(&ip, DATA(packet) + ether_size, ip_size);
+
+	/* Remember original source and destination */
+
+	ip_src = ip.ip_src;
+	ip_dst = ip.ip_dst;
+
+	/* Try to reply with an IP address assigned to the local machine */
+
+	if(type == ICMP_TIME_EXCEEDED && code == ICMP_EXC_TTL) {
+		int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+
+		if(sockfd != -1) {
+			struct sockaddr_in addr;
+			memset(&addr, 0, sizeof(addr));
+			addr.sin_family = AF_INET;
+			addr.sin_addr = ip.ip_src;
+
+			if(!connect(sockfd, (const struct sockaddr *) &addr, sizeof(addr))) {
+				memset(&addr, 0, sizeof(addr));
+				addr.sin_family = AF_INET;
+				socklen_t addrlen = sizeof(addr);
+
+				if(!getsockname(sockfd, (struct sockaddr *) &addr, &addrlen) && (size_t)addrlen <= sizeof(addr)) {
+					ip_dst = addr.sin_addr;
+				}
+			}
+
+			close(sockfd);
+		}
+	}
+
+	oldlen = packet->len - ether_size;
+
+	if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+		icmp.icmp_nextmtu = htons(packet->len - ether_size);
+	}
+
+	if(oldlen >= IP_MSS - ip_size - icmp_size) {
+		oldlen = IP_MSS - ip_size - icmp_size;
+	}
+
+	/* Copy first part of original contents to ICMP message */
+
+	memmove(DATA(packet) + ether_size + ip_size + icmp_size, DATA(packet) + ether_size, oldlen);
+
+	/* Fill in IPv4 header */
+
+	ip.ip_v = 4;
+	ip.ip_hl = ip_size / 4;
+	ip.ip_tos = 0;
+	ip.ip_len = htons(ip_size + icmp_size + oldlen);
+	ip.ip_id = 0;
+	ip.ip_off = 0;
+	ip.ip_ttl = 255;
+	ip.ip_p = IPPROTO_ICMP;
+	ip.ip_sum = 0;
+	ip.ip_src = ip_dst;
+	ip.ip_dst = ip_src;
+
+	ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
+
+	/* Fill in ICMP header */
+
+	icmp.icmp_type = type;
+	icmp.icmp_code = code;
+	icmp.icmp_cksum = 0;
+
+	icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0);
+	icmp.icmp_cksum = inet_checksum(DATA(packet) + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
+
+	/* Copy structs on stack back to packet */
+
+	memcpy(DATA(packet) + ether_size, &ip, ip_size);
+	memcpy(DATA(packet) + ether_size + ip_size, &icmp, icmp_size);
+
+	packet->len = ether_size + ip_size + icmp_size + oldlen;
+
+	send_packet(source, packet);
+}
+
+/* RFC 2463 */
+
+static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
+	struct ip6_hdr ip6;
+	struct icmp6_hdr icmp6 = {0};
+	uint16_t checksum;
+
+	struct {
+		struct in6_addr ip6_src;        /* source address */
+		struct in6_addr ip6_dst;        /* destination address */
+		uint32_t length;
+		uint32_t next;
+	} pseudo;
+
+	if(ratelimit(3)) {
+		return;
+	}
+
+	/* Swap Ethernet source and destination addresses */
+
+	swap_mac_addresses(packet);
+
+	/* Copy headers from packet to structs on the stack */
+
+	memcpy(&ip6, DATA(packet) + ether_size, ip6_size);
+
+	/* Remember original source and destination */
+
+	pseudo.ip6_src = ip6.ip6_dst;
+	pseudo.ip6_dst = ip6.ip6_src;
+
+	/* Try to reply with an IP address assigned to the local machine */
+
+	if(type == ICMP6_TIME_EXCEEDED && code == ICMP6_TIME_EXCEED_TRANSIT) {
+		int sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+
+		if(sockfd != -1) {
+			struct sockaddr_in6 addr;
+			memset(&addr, 0, sizeof(addr));
+			addr.sin6_family = AF_INET6;
+			addr.sin6_addr = ip6.ip6_src;
+
+			if(!connect(sockfd, (const struct sockaddr *) &addr, sizeof(addr))) {
+				memset(&addr, 0, sizeof(addr));
+				addr.sin6_family = AF_INET6;
+				socklen_t addrlen = sizeof(addr);
+
+				if(!getsockname(sockfd, (struct sockaddr *) &addr, &addrlen) && (size_t)addrlen <= sizeof(addr)) {
+					pseudo.ip6_src = addr.sin6_addr;
+				}
+			}
+
+			close(sockfd);
+		}
+	}
+
+	pseudo.length = packet->len - ether_size;
+
+	if(type == ICMP6_PACKET_TOO_BIG) {
+		icmp6.icmp6_mtu = htonl(pseudo.length);
+	}
+
+	if(pseudo.length >= IP_MSS - ip6_size - icmp6_size) {
+		pseudo.length = IP_MSS - ip6_size - icmp6_size;
+	}
+
+	/* Copy first part of original contents to ICMP message */
+
+	memmove(DATA(packet) + ether_size + ip6_size + icmp6_size, DATA(packet) + ether_size, pseudo.length);
+
+	/* Fill in IPv6 header */
+
+	ip6.ip6_flow = htonl(0x60000000UL);
+	ip6.ip6_plen = htons(icmp6_size + pseudo.length);
+	ip6.ip6_nxt = IPPROTO_ICMPV6;
+	ip6.ip6_hlim = 255;
+	ip6.ip6_src = pseudo.ip6_src;
+	ip6.ip6_dst = pseudo.ip6_dst;
+
+	/* Fill in ICMP header */
+
+	icmp6.icmp6_type = type;
+	icmp6.icmp6_code = code;
+	icmp6.icmp6_cksum = 0;
+
+	/* Create pseudo header */
+
+	pseudo.length = htonl(icmp6_size + pseudo.length);
+	pseudo.next = htonl(IPPROTO_ICMPV6);
+
+	/* Generate checksum */
+
+	checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
+	checksum = inet_checksum(&icmp6, icmp6_size, checksum);
+	checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
+
+	icmp6.icmp6_cksum = checksum;
+
+	/* Copy structs on stack back to packet */
+
+	memcpy(DATA(packet) + ether_size, &ip6, ip6_size);
+	memcpy(DATA(packet) + ether_size + ip6_size, &icmp6, icmp6_size);
+
+	packet->len = ether_size + ip6_size + ntohl(pseudo.length);
+
+	send_packet(source, packet);
+}
+
+static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
+	uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
+	length_t ethlen = ether_size;
+
+	if(type == ETH_P_8021Q) {
+		type = DATA(packet)[16] << 8 | DATA(packet)[17];
+		ethlen += 4;
+	}
+
+	switch(type) {
+	case ETH_P_IP:
+		if(!checklength(source, packet, ethlen + ip_size)) {
+			return false;
+		}
+
+		if(DATA(packet)[ethlen + 8] <= 1) {
+			if(DATA(packet)[ethlen + 11] != IPPROTO_ICMP || DATA(packet)[ethlen + 32] != ICMP_TIME_EXCEEDED) {
+				route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
+			}
+
+			return false;
+		}
+
+		uint16_t old = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
+		DATA(packet)[ethlen + 8]--;
+		uint16_t new = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
+
+		uint32_t checksum = DATA(packet)[ethlen + 10] << 8 | DATA(packet)[ethlen + 11];
+		checksum += old + (~new & 0xFFFF);
+
+		while(checksum >> 16) {
+			checksum = (checksum & 0xFFFF) + (checksum >> 16);
+		}
+
+		DATA(packet)[ethlen + 10] = checksum >> 8;
+		DATA(packet)[ethlen + 11] = checksum & 0xff;
+
+		return true;
+
+	case ETH_P_IPV6:
+		if(!checklength(source, packet, ethlen + ip6_size)) {
+			return false;
+		}
+
+		if(DATA(packet)[ethlen + 7] <= 1) {
+			if(DATA(packet)[ethlen + 6] != IPPROTO_ICMPV6 || DATA(packet)[ethlen + 40] != ICMP6_TIME_EXCEEDED) {
+				route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
+			}
+
+			return false;
+		}
+
+		DATA(packet)[ethlen + 7]--;
+
+		return true;
+
+	default:
 		return true;
+	}
 }
 
 static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
-	if(!source || !via || !(via->options & OPTION_CLAMP_MSS))
+	if(!source || !via || !(via->options & OPTION_CLAMP_MSS)) {
 		return;
+	}
 
 	uint16_t mtu = source->mtu;
-	if(via != myself && via->mtu < mtu)
+
+	if(via != myself && via->mtu < mtu) {
 		mtu = via->mtu;
+	}
 
 	/* Find TCP header */
 	int start = ether_size;
@@ -122,52 +412,70 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		type = DATA(packet)[16] << 8 | DATA(packet)[17];
 	}
 
-	if(type == ETH_P_IP && DATA(packet)[start + 9] == 6)
+	/* IP in IP (RFC 2003) packet */
+	if(type == ETH_P_IP && DATA(packet)[start + 9] == 4) {
+		start += 20;
+	}
+
+	if(packet->len <= start + 20) {
+		return;
+	}
+
+	if(type == ETH_P_IP && DATA(packet)[start + 9] == 6) {
 		start += (DATA(packet)[start] & 0xf) * 4;
-	else if(type == ETH_P_IPV6 && DATA(packet)[start + 6] == 6)
+	} else if(type == ETH_P_IPV6 && DATA(packet)[start + 6] == 6) {
 		start += 40;
-	else
+	} else {
 		return;
+	}
 
-	if(packet->len <= start + 20)
+	if(packet->len <= start + 20) {
 		return;
+	}
 
 	/* Use data offset field to calculate length of options field */
 	int len = ((DATA(packet)[start + 12] >> 4) - 5) * 4;
 
-	if(packet->len < start + 20 + len)
+	if(packet->len < start + 20 + len) {
 		return;
+	}
 
 	/* Search for MSS option header */
 	for(int i = 0; i < len;) {
-		if(DATA(packet)[start + 20 + i] == 0)
+		if(DATA(packet)[start + 20 + i] == 0) {
 			break;
+		}
 
 		if(DATA(packet)[start + 20 + i] == 1) {
 			i++;
 			continue;
 		}
 
-		if(i > len - 2 || i > len - DATA(packet)[start + 21 + i])
+		if(i > len - 2 || i > len - DATA(packet)[start + 21 + i]) {
 			break;
+		}
 
 		if(DATA(packet)[start + 20 + i] != 2) {
-			if(DATA(packet)[start + 21 + i] < 2)
+			if(DATA(packet)[start + 21 + i] < 2) {
 				break;
+			}
+
 			i += DATA(packet)[start + 21 + i];
 			continue;
 		}
 
-		if(DATA(packet)[start + 21] != 4)
+		if(DATA(packet)[start + 21] != 4) {
 			break;
+		}
 
 		/* Found it */
 		uint16_t oldmss = DATA(packet)[start + 22 + i] << 8 | DATA(packet)[start + 23 + i];
 		uint16_t newmss = mtu - start - 20;
 		uint32_t csum = DATA(packet)[start + 16] << 8 | DATA(packet)[start + 17];
 
-		if(oldmss <= newmss)
+		if(oldmss <= newmss) {
 			break;
+		}
 
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Clamping MSS of packet from %s to %s to %d", source->name, via->name, newmss);
 
@@ -186,37 +494,37 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 	}
 }
 
-static void swap_mac_addresses(vpn_packet_t *packet) {
-	mac_t tmp;
-	memcpy(&tmp, &DATA(packet)[0], sizeof tmp);
-	memcpy(&DATA(packet)[0], &DATA(packet)[6], sizeof tmp);
-	memcpy(&DATA(packet)[6], &tmp, sizeof tmp);
-}
-
 static void age_subnets(void *data) {
+	(void)data;
 	bool left = false;
 
 	for splay_each(subnet_t, s, myself->subnet_tree) {
 		if(s->expires && s->expires < now.tv_sec) {
 			if(debug_level >= DEBUG_TRAFFIC) {
 				char netstr[MAXNETSTR];
-				if(net2str(netstr, sizeof netstr, s))
+
+				if(net2str(netstr, sizeof(netstr), s)) {
 					logger(DEBUG_TRAFFIC, LOG_INFO, "Subnet %s expired", netstr);
+				}
 			}
 
 			for list_each(connection_t, c, connection_list)
-				if(c->edge)
+				if(c->edge) {
 					send_del_subnet(c, s);
+				}
 
 			subnet_del(myself, s);
 		} else {
-			if(s->expires)
+			if(s->expires) {
 				left = true;
+			}
 		}
 	}
 
 	if(left)
-		timeout_set(&age_subnets_timeout, &(struct timeval){10, rand() % 100000});
+		timeout_set(&age_subnets_timeout, &(struct timeval) {
+		10, rand() % 100000
+	});
 }
 
 static void learn_mac(mac_t *address) {
@@ -226,8 +534,8 @@ static void learn_mac(mac_t *address) {
 
 	if(!subnet) {
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Learned new MAC address %x:%x:%x:%x:%x:%x",
-				   address->x[0], address->x[1], address->x[2], address->x[3],
-				   address->x[4], address->x[5]);
+		       address->x[0], address->x[1], address->x[2], address->x[3],
+		       address->x[4], address->x[5]);
 
 		subnet = new_subnet();
 		subnet->type = SUBNET_MAC;
@@ -240,87 +548,27 @@ static void learn_mac(mac_t *address) {
 		/* And tell all other tinc daemons it's our MAC */
 
 		for list_each(connection_t, c, connection_list)
-			if(c->edge)
+			if(c->edge) {
 				send_add_subnet(c, subnet);
+			}
 
-		timeout_add(&age_subnets_timeout, age_subnets, NULL, &(struct timeval){10, rand() % 100000});
+		timeout_add(&age_subnets_timeout, age_subnets, NULL, &(struct timeval) {
+			10, rand() % 100000
+		});
 	} else {
-		if(subnet->expires)
+		if(subnet->expires) {
 			subnet->expires = now.tv_sec + macexpire;
+		}
 	}
 }
 
-/* RFC 792 */
-
-static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
-	struct ip ip = {0};
-	struct icmp icmp = {0};
-
-	struct in_addr ip_src;
-	struct in_addr ip_dst;
-	uint32_t oldlen;
-
-	if(ratelimit(3))
-		return;
-
-	/* Swap Ethernet source and destination addresses */
-
-	swap_mac_addresses(packet);
-
-	/* Copy headers from packet into properly aligned structs on the stack */
-
-	memcpy(&ip, DATA(packet) + ether_size, ip_size);
-
-	/* Remember original source and destination */
-
-	ip_src = ip.ip_src;
-	ip_dst = ip.ip_dst;
-
-	oldlen = packet->len - ether_size;
-
-	if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
-		icmp.icmp_nextmtu = htons(packet->len - ether_size);
-
-	if(oldlen >= IP_MSS - ip_size - icmp_size)
-		oldlen = IP_MSS - ip_size - icmp_size;
-
-	/* Copy first part of original contents to ICMP message */
-
-	memmove(DATA(packet) + ether_size + ip_size + icmp_size, DATA(packet) + ether_size, oldlen);
-
-	/* Fill in IPv4 header */
-
-	ip.ip_v = 4;
-	ip.ip_hl = ip_size / 4;
-	ip.ip_tos = 0;
-	ip.ip_len = htons(ip_size + icmp_size + oldlen);
-	ip.ip_id = 0;
-	ip.ip_off = 0;
-	ip.ip_ttl = 255;
-	ip.ip_p = IPPROTO_ICMP;
-	ip.ip_sum = 0;
-	ip.ip_src = ip_dst;
-	ip.ip_dst = ip_src;
-
-	ip.ip_sum = inet_checksum(&ip, ip_size, ~0);
-
-	/* Fill in ICMP header */
-
-	icmp.icmp_type = type;
-	icmp.icmp_code = code;
-	icmp.icmp_cksum = 0;
-
-	icmp.icmp_cksum = inet_checksum(&icmp, icmp_size, ~0);
-	icmp.icmp_cksum = inet_checksum(DATA(packet) + ether_size + ip_size + icmp_size, oldlen, icmp.icmp_cksum);
-
-	/* Copy structs on stack back to packet */
-
-	memcpy(DATA(packet) + ether_size, &ip, ip_size);
-	memcpy(DATA(packet) + ether_size + ip_size, &icmp, icmp_size);
-
-	packet->len = ether_size + ip_size + icmp_size + oldlen;
+static void route_broadcast(node_t *source, vpn_packet_t *packet) {
+	if(decrement_ttl && source != myself)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
-	send_packet(source, packet);
+	broadcast_packet(source, packet);
 }
 
 /* RFC 791 */
@@ -328,7 +576,7 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_
 static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t ether_size) {
 	struct ip ip;
 	vpn_packet_t fragment;
-	int len, maxlen, todo;
+	int maxlen, todo;
 	uint8_t *offset;
 	uint16_t ip_off, origf;
 
@@ -336,8 +584,9 @@ static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t et
 	fragment.priority = packet->priority;
 	fragment.offset = DEFAULT_PACKET_OFFSET;
 
-	if(ip.ip_hl != ip_size / 4)
+	if(ip.ip_hl != ip_size / 4) {
 		return;
+	}
 
 	todo = ntohs(ip.ip_len) - ip_size;
 
@@ -349,13 +598,13 @@ static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t et
 	logger(DEBUG_TRAFFIC, LOG_INFO, "Fragmenting packet of %d bytes to %s (%s)", packet->len, dest->name, dest->hostname);
 
 	offset = DATA(packet) + ether_size + ip_size;
-	maxlen = (dest->mtu - ether_size - ip_size) & ~0x7;
+	maxlen = (MAX(dest->mtu, 590) - ether_size - ip_size) & ~0x7;
 	ip_off = ntohs(ip.ip_off);
 	origf = ip_off & ~IP_OFFMASK;
 	ip_off &= IP_OFFMASK;
 
 	while(todo) {
-		len = todo > maxlen ? maxlen : todo;
+		int len = todo > maxlen ? maxlen : todo;
 		memcpy(DATA(&fragment) + ether_size + ip_size, offset, len);
 		todo -= len;
 		offset += len;
@@ -375,30 +624,31 @@ static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet, length_t et
 }
 
 static void route_ipv4(node_t *source, vpn_packet_t *packet) {
-	if(!checklength(source, packet, ether_size + ip_size))
+	if(!checklength(source, packet, ether_size + ip_size)) {
 		return;
+	}
 
 	subnet_t *subnet;
 	node_t *via;
 	ipv4_t dest;
 
-	memcpy(&dest, &DATA(packet)[30], sizeof dest);
+	memcpy(&dest, &DATA(packet)[30], sizeof(dest));
 	subnet = lookup_subnet_ipv4(&dest);
 
 	if(!subnet) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d",
-				source->name, source->hostname,
-				dest.x[0],
-				dest.x[1],
-				dest.x[2],
-				dest.x[3]);
+		       source->name, source->hostname,
+		       dest.x[0],
+		       dest.x[1],
+		       dest.x[2],
+		       dest.x[3]);
 
 		route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
 		return;
 	}
 
-	if (!subnet->owner) {
-		broadcast_packet(source, packet);
+	if(!subnet->owner) {
+		route_broadcast(source, packet);
 		return;
 	}
 
@@ -407,14 +657,24 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(!subnet->owner->status.reachable)
-		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+	if(!subnet->owner->status.reachable) {
+		route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+		return;
+	}
 
-	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
-		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
+		route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+		return;
+	}
+
+	if(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
-	if(priorityinheritance)
+	if(priorityinheritance) {
 		packet->priority = DATA(packet)[15];
+	}
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 
@@ -423,11 +683,14 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(directonly && subnet->owner != via)
-		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+	if(directonly && subnet->owner != via) {
+		route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+		return;
+	}
 
 	if(via && packet->len > MAX(via->mtu, 590) && via != myself) {
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
+
 		if(DATA(packet)[20] & 0x40) {
 			packet->len = MAX(via->mtu, 590);
 			route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
@@ -443,91 +706,12 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 	send_packet(subnet->owner, packet);
 }
 
-/* RFC 2463 */
-
-static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_t ether_size, uint8_t type, uint8_t code) {
-	struct ip6_hdr ip6;
-	struct icmp6_hdr icmp6 = {0};
-	uint16_t checksum;
-
-	struct {
-		struct in6_addr ip6_src;        /* source address */
-		struct in6_addr ip6_dst;        /* destination address */
-		uint32_t length;
-		uint32_t next;
-	} pseudo;
-
-	if(ratelimit(3))
-		return;
-
-	/* Swap Ethernet source and destination addresses */
-
-	swap_mac_addresses(packet);
-
-	/* Copy headers from packet to structs on the stack */
-
-	memcpy(&ip6, DATA(packet) + ether_size, ip6_size);
-
-	/* Remember original source and destination */
-
-	pseudo.ip6_src = ip6.ip6_dst;
-	pseudo.ip6_dst = ip6.ip6_src;
-
-	pseudo.length = packet->len - ether_size;
-
-	if(type == ICMP6_PACKET_TOO_BIG)
-		icmp6.icmp6_mtu = htonl(pseudo.length);
-
-	if(pseudo.length >= IP_MSS - ip6_size - icmp6_size)
-		pseudo.length = IP_MSS - ip6_size - icmp6_size;
-
-	/* Copy first part of original contents to ICMP message */
-
-	memmove(DATA(packet) + ether_size + ip6_size + icmp6_size, DATA(packet) + ether_size, pseudo.length);
-
-	/* Fill in IPv6 header */
-
-	ip6.ip6_flow = htonl(0x60000000UL);
-	ip6.ip6_plen = htons(icmp6_size + pseudo.length);
-	ip6.ip6_nxt = IPPROTO_ICMPV6;
-	ip6.ip6_hlim = 255;
-	ip6.ip6_src = pseudo.ip6_src;
-	ip6.ip6_dst = pseudo.ip6_dst;
-
-	/* Fill in ICMP header */
-
-	icmp6.icmp6_type = type;
-	icmp6.icmp6_code = code;
-	icmp6.icmp6_cksum = 0;
-
-	/* Create pseudo header */
-
-	pseudo.length = htonl(icmp6_size + pseudo.length);
-	pseudo.next = htonl(IPPROTO_ICMPV6);
-
-	/* Generate checksum */
-
-	checksum = inet_checksum(&pseudo, sizeof pseudo, ~0);
-	checksum = inet_checksum(&icmp6, icmp6_size, checksum);
-	checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
-
-	icmp6.icmp6_cksum = checksum;
-
-	/* Copy structs on stack back to packet */
-
-	memcpy(DATA(packet) + ether_size, &ip6, ip6_size);
-	memcpy(DATA(packet) + ether_size + ip6_size, &icmp6, icmp6_size);
-
-	packet->len = ether_size + ip6_size + ntohl(pseudo.length);
-
-	send_packet(source, packet);
-}
-
 static void route_neighborsol(node_t *source, vpn_packet_t *packet);
 
 static void route_ipv6(node_t *source, vpn_packet_t *packet) {
-	if(!checklength(source, packet, ether_size + ip6_size))
+	if(!checklength(source, packet, ether_size + ip6_size)) {
 		return;
+	}
 
 	if(DATA(packet)[20] == IPPROTO_ICMPV6 && checklength(source, packet, ether_size + ip6_size + icmp6_size) && DATA(packet)[54] == ND_NEIGHBOR_SOLICIT) {
 		route_neighborsol(source, packet);
@@ -538,27 +722,27 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 	node_t *via;
 	ipv6_t dest;
 
-	memcpy(&dest, &DATA(packet)[38], sizeof dest);
+	memcpy(&dest, &DATA(packet)[38], sizeof(dest));
 	subnet = lookup_subnet_ipv6(&dest);
 
 	if(!subnet) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
-				source->name, source->hostname,
-				ntohs(dest.x[0]),
-				ntohs(dest.x[1]),
-				ntohs(dest.x[2]),
-				ntohs(dest.x[3]),
-				ntohs(dest.x[4]),
-				ntohs(dest.x[5]),
-				ntohs(dest.x[6]),
-				ntohs(dest.x[7]));
+		       source->name, source->hostname,
+		       ntohs(dest.x[0]),
+		       ntohs(dest.x[1]),
+		       ntohs(dest.x[2]),
+		       ntohs(dest.x[3]),
+		       ntohs(dest.x[4]),
+		       ntohs(dest.x[5]),
+		       ntohs(dest.x[6]),
+		       ntohs(dest.x[7]));
 
 		route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
 		return;
 	}
 
-	if (!subnet->owner) {
-		broadcast_packet(source, packet);
+	if(!subnet->owner) {
+		route_broadcast(source, packet);
 		return;
 	}
 
@@ -567,11 +751,24 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(!subnet->owner->status.reachable)
-		return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+	if(!subnet->owner->status.reachable) {
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+		return;
+	}
+
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+		return;
+	}
+
+	if(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
-	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
-		return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+	if(priorityinheritance) {
+		packet->priority = ((DATA(packet)[14] & 0x0f) << 4) | (DATA(packet)[15] >> 4);
+	}
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 
@@ -580,8 +777,10 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(directonly && subnet->owner != via)
-		return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+	if(directonly && subnet->owner != via) {
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+		return;
+	}
 
 	if(via && packet->len > MAX(via->mtu, 1294) && via != myself) {
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
@@ -612,8 +811,9 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 		uint32_t next;
 	} pseudo;
 
-	if(!checklength(source, packet, ether_size + ip6_size + ns_size))
+	if(!checklength(source, packet, ether_size + ip6_size + ns_size)) {
 		return;
+	}
 
 	has_opt = packet->len >= ether_size + ip6_size + ns_size + opt_size + ETH_ALEN;
 
@@ -626,18 +826,21 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	memcpy(&ip6, DATA(packet) + ether_size, ip6_size);
 	memcpy(&ns, DATA(packet) + ether_size + ip6_size, ns_size);
-	if(has_opt)
+
+	if(has_opt) {
 		memcpy(&opt, DATA(packet) + ether_size + ip6_size + ns_size, opt_size);
+	}
 
 	/* First, snatch the source address from the neighbor solicitation packet */
 
-	if(overwrite_mac)
+	if(overwrite_mac) {
 		memcpy(mymac.x, DATA(packet) + ETH_ALEN, ETH_ALEN);
+	}
 
 	/* Check if this is a valid neighbor solicitation request */
 
 	if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
-	   (has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) {
+	                (has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: received unknown type neighbor solicitation request");
 		return;
 	}
@@ -646,16 +849,20 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	pseudo.ip6_src = ip6.ip6_src;
 	pseudo.ip6_dst = ip6.ip6_dst;
-	if(has_opt)
+
+	if(has_opt) {
 		pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
-	else
+	} else {
 		pseudo.length = htonl(ns_size);
+	}
+
 	pseudo.next = htonl(IPPROTO_ICMPV6);
 
 	/* Generate checksum */
 
-	checksum = inet_checksum(&pseudo, sizeof pseudo, ~0);
+	checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 	checksum = inet_checksum(&ns, ns_size, checksum);
+
 	if(has_opt) {
 		checksum = inet_checksum(&opt, opt_size, checksum);
 		checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
@@ -672,33 +879,40 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	if(!subnet) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[0]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[1]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[2]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[3]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[4]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[5]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[6]),
-				   ntohs(((uint16_t *) &ns.nd_ns_target)[7]));
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[0]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[1]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[2]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[3]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[4]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[5]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[6]),
+		       ntohs(((uint16_t *) &ns.nd_ns_target)[7]));
 
 		return;
 	}
 
 	/* Check if it is for our own subnet */
 
-	if(subnet->owner == myself)
-		return;                                          /* silently ignore */
+	if(subnet->owner == myself) {
+		return;        /* silently ignore */
+	}
+
+	if(decrement_ttl)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
 	/* Create neighbor advertation reply */
 
 	memcpy(DATA(packet), DATA(packet) + ETH_ALEN, ETH_ALEN); /* copy destination address */
 	DATA(packet)[ETH_ALEN * 2 - 1] ^= 0xFF;                  /* mangle source address so it looks like it's not from us */
 
-	ip6.ip6_dst = ip6.ip6_src;                               /* swap destination and source protocoll address */
+	ip6.ip6_dst = ip6.ip6_src;                               /* swap destination and source protocol address */
 	ip6.ip6_src = ns.nd_ns_target;
 
-	if(has_opt)
-		memcpy(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, DATA(packet) + ETH_ALEN, ETH_ALEN);   /* add fake source hard addr */
+	if(has_opt) {
+		memcpy(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, DATA(packet) + ETH_ALEN, ETH_ALEN);        /* add fake source hard addr */
+	}
 
 	ns.nd_ns_cksum = 0;
 	ns.nd_ns_type = ND_NEIGHBOR_ADVERT;
@@ -709,16 +923,20 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	pseudo.ip6_src = ip6.ip6_src;
 	pseudo.ip6_dst = ip6.ip6_dst;
-	if(has_opt)
+
+	if(has_opt) {
 		pseudo.length = htonl(ns_size + opt_size + ETH_ALEN);
-	else
+	} else {
 		pseudo.length = htonl(ns_size);
+	}
+
 	pseudo.next = htonl(IPPROTO_ICMPV6);
 
 	/* Generate checksum */
 
-	checksum = inet_checksum(&pseudo, sizeof pseudo, ~0);
+	checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
 	checksum = inet_checksum(&ns, ns_size, checksum);
+
 	if(has_opt) {
 		checksum = inet_checksum(&opt, opt_size, checksum);
 		checksum = inet_checksum(DATA(packet) + ether_size + ip6_size + ns_size + opt_size, ETH_ALEN, checksum);
@@ -730,8 +948,10 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	memcpy(DATA(packet) + ether_size, &ip6, ip6_size);
 	memcpy(DATA(packet) + ether_size + ip6_size, &ns, ns_size);
-	if(has_opt)
+
+	if(has_opt) {
 		memcpy(DATA(packet) + ether_size + ip6_size + ns_size, &opt, opt_size);
+	}
 
 	send_packet(source, packet);
 }
@@ -743,8 +963,9 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	subnet_t *subnet;
 	struct in_addr addr;
 
-	if(!checklength(source, packet, ether_size + arp_size))
+	if(!checklength(source, packet, ether_size + arp_size)) {
 		return;
+	}
 
 	if(source != myself) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Got ARP request from %s (%s) while in router mode!", source->name, source->hostname);
@@ -753,8 +974,9 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 
 	/* First, snatch the source address from the ARP packet */
 
-	if(overwrite_mac)
+	if(overwrite_mac) {
 		memcpy(mymac.x, DATA(packet) + ETH_ALEN, ETH_ALEN);
+	}
 
 	/* Copy headers from packet to structs on the stack */
 
@@ -763,7 +985,7 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	/* Check if this is a valid ARP request */
 
 	if(ntohs(arp.arp_hrd) != ARPHRD_ETHER || ntohs(arp.arp_pro) != ETH_P_IP ||
-	   arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof addr || ntohs(arp.arp_op) != ARPOP_REQUEST) {
+	                arp.arp_hln != ETH_ALEN || arp.arp_pln != sizeof(addr) || ntohs(arp.arp_op) != ARPOP_REQUEST) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: received unknown type ARP request");
 		return;
 	}
@@ -774,19 +996,25 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 
 	if(!subnet) {
 		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: ARP request for unknown address %d.%d.%d.%d",
-				   arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
-				   arp.arp_tpa[3]);
+		       arp.arp_tpa[0], arp.arp_tpa[1], arp.arp_tpa[2],
+		       arp.arp_tpa[3]);
 		return;
 	}
 
 	/* Check if it is for our own subnet */
 
-	if(subnet->owner == myself)
-		return;                                          /* silently ignore */
+	if(subnet->owner == myself) {
+		return;        /* silently ignore */
+	}
+
+	if(decrement_ttl)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
-	memcpy(&addr, arp.arp_tpa, sizeof addr);                 /* save protocol addr */
-	memcpy(arp.arp_tpa, arp.arp_spa, sizeof addr);           /* swap destination and source protocol address */
-	memcpy(arp.arp_spa, &addr, sizeof addr);                 /* ... */
+	memcpy(&addr, arp.arp_tpa, sizeof(addr));                 /* save protocol addr */
+	memcpy(arp.arp_tpa, arp.arp_spa, sizeof(addr));           /* swap destination and source protocol address */
+	memcpy(arp.arp_spa, &addr, sizeof(addr));                 /* ... */
 
 	memcpy(arp.arp_tha, arp.arp_sha, ETH_ALEN);              /* set target hard/proto addr */
 	memcpy(arp.arp_sha, DATA(packet) + ETH_ALEN, ETH_ALEN);  /* set source hard/proto addr */
@@ -808,17 +1036,17 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 
 	if(source == myself) {
 		mac_t src;
-		memcpy(&src, &DATA(packet)[6], sizeof src);
+		memcpy(&src, &DATA(packet)[6], sizeof(src));
 		learn_mac(&src);
 	}
 
 	/* Lookup destination address */
 
-	memcpy(&dest, &DATA(packet)[0], sizeof dest);
+	memcpy(&dest, &DATA(packet)[0], sizeof(dest));
 	subnet = lookup_subnet_mac(NULL, &dest);
 
 	if(!subnet || !subnet->owner) {
-		broadcast_packet(source, packet);
+		route_broadcast(source, packet);
 		return;
 	}
 
@@ -827,20 +1055,32 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself) {
 		return;
+	}
+
+	if(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet)) {
+			return;
+		}
 
 	uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
 
-	if(priorityinheritance && type == ETH_P_IP && packet->len >= ether_size + ip_size)
-		packet->priority = DATA(packet)[15];
+	if(priorityinheritance) {
+		if(type == ETH_P_IP && packet->len >= ether_size + ip_size) {
+			packet->priority = DATA(packet)[15];
+		} else if(type == ETH_P_IPV6 && packet->len >= ether_size + ip6_size) {
+			packet->priority = ((DATA(packet)[14] & 0x0f) << 4) | (DATA(packet)[15] >> 4);
+		}
+	}
 
 	// Handle packets larger than PMTU
 
 	node_t *via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 
-	if(directonly && subnet->owner != via)
+	if(directonly && subnet->owner != via) {
 		return;
+	}
 
 	if(via && packet->len > via->mtu && via != myself) {
 		logger(DEBUG_TRAFFIC, LOG_INFO, "Packet for %s (%s) length %d larger than MTU %d", subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
@@ -858,6 +1098,7 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 			} else {
 				fragment_ipv4_packet(via, packet, ethlen);
 			}
+
 			return;
 		} else if(type == ETH_P_IPV6 && packet->len > 1280 + ethlen) {
 			packet->len = via->mtu;
@@ -875,116 +1116,67 @@ static void send_pcap(vpn_packet_t *packet) {
 	pcap = false;
 
 	for list_each(connection_t, c, connection_list) {
-		if(!c->status.pcap)
+		if(!c->status.pcap) {
 			continue;
+		}
 
 		pcap = true;
 		int len = packet->len;
-		if(c->outmaclength && c->outmaclength < len)
+
+		if(c->outmaclength && c->outmaclength < len) {
 			len = c->outmaclength;
+		}
 
-		if(send_request(c, "%d %d %d", CONTROL, REQ_PCAP, len))
+		if(send_request(c, "%d %d %d", CONTROL, REQ_PCAP, len)) {
 			send_meta(c, (char *)DATA(packet), len);
-	}
-}
-
-static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
-	uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
-	length_t ethlen = ether_size;
-
-	if(type == ETH_P_8021Q) {
-		type = DATA(packet)[16] << 8 | DATA(packet)[17];
-		ethlen += 4;
-	}
-
-	switch (type) {
-		case ETH_P_IP:
-			if(!checklength(source, packet, ethlen + ip_size))
-				return false;
-
-			if(DATA(packet)[ethlen + 8] <= 1) {
-				if(DATA(packet)[ethlen + 11] != IPPROTO_ICMP || DATA(packet)[ethlen + 32] != ICMP_TIME_EXCEEDED)
-					route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
-				return false;
-			}
-
-			uint16_t old = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
-			DATA(packet)[ethlen + 8]--;
-			uint16_t new = DATA(packet)[ethlen + 8] << 8 | DATA(packet)[ethlen + 9];
-
-			uint32_t checksum = DATA(packet)[ethlen + 10] << 8 | DATA(packet)[ethlen + 11];
-			checksum += old + (~new & 0xFFFF);
-			while(checksum >> 16)
-				checksum = (checksum & 0xFFFF) + (checksum >> 16);
-			DATA(packet)[ethlen + 10] = checksum >> 8;
-			DATA(packet)[ethlen + 11] = checksum & 0xff;
-
-			return true;
-
-		case ETH_P_IPV6:
-			if(!checklength(source, packet, ethlen + ip6_size))
-				return false;
-
-			if(DATA(packet)[ethlen + 7] <= 1) {
-				if(DATA(packet)[ethlen + 6] != IPPROTO_ICMPV6 || DATA(packet)[ethlen + 40] != ICMP6_TIME_EXCEEDED)
-					route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
-				return false;
-			}
-
-			DATA(packet)[ethlen + 7]--;
-
-			return true;
-
-		default:
-			return true;
+		}
 	}
 }
 
 void route(node_t *source, vpn_packet_t *packet) {
-	if(pcap)
+	if(pcap) {
 		send_pcap(packet);
+	}
 
 	if(forwarding_mode == FMODE_KERNEL && source != myself) {
 		send_packet(myself, packet);
 		return;
 	}
 
-	if(!checklength(source, packet, ether_size))
+	if(!checklength(source, packet, ether_size)) {
 		return;
-
-	if(decrement_ttl && source != myself)
-		if(!do_decrement_ttl(source, packet))
-			return;
+	}
 
 	uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
 
-	switch (routing_mode) {
-		case RMODE_ROUTER:
-			switch (type) {
-				case ETH_P_ARP:
-					route_arp(source, packet);
-					break;
-
-				case ETH_P_IP:
-					route_ipv4(source, packet);
-					break;
-
-				case ETH_P_IPV6:
-					route_ipv6(source, packet);
-					break;
+	switch(routing_mode) {
+	case RMODE_ROUTER:
+		switch(type) {
+		case ETH_P_ARP:
+			route_arp(source, packet);
+			break;
 
-				default:
-					logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown type %hx", source->name, source->hostname, type);
-					break;
-			}
+		case ETH_P_IP:
+			route_ipv4(source, packet);
 			break;
 
-		case RMODE_SWITCH:
-			route_mac(source, packet);
+		case ETH_P_IPV6:
+			route_ipv6(source, packet);
 			break;
 
-		case RMODE_HUB:
-			broadcast_packet(source, packet);
+		default:
+			logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown type %hx", source->name, source->hostname, type);
 			break;
+		}
+
+		break;
+
+	case RMODE_SWITCH:
+		route_mac(source, packet);
+		break;
+
+	case RMODE_HUB:
+		route_broadcast(source, packet);
+		break;
 	}
 }