X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=9b939580b4a58b86800bd00b40ec30afb374a973;hp=7538bec517c8a70a42bf6d566d63448e8d6f5d44;hb=ff306f0cdaedb50de1472e7c1fb55de922a6ca60;hpb=a227843b739d279b63adcf3736ebb03d856080c4

diff --git a/src/route.c b/src/route.c
index 7538bec5..9b939580 100644
--- a/src/route.c
+++ b/src/route.c
@@ -1,7 +1,7 @@
 /*
     route.c -- routing
     Copyright (C) 2000-2005 Ivo Timmermans,
-                  2000-2009 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2012 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
@@ -20,12 +20,13 @@
 
 #include "system.h"
 
-#include "avl_tree.h"
 #include "connection.h"
+#include "control_common.h"
 #include "ethernet.h"
 #include "ipv4.h"
 #include "ipv6.h"
 #include "logger.h"
+#include "meta.h"
 #include "net.h"
 #include "protocol.h"
 #include "route.h"
@@ -33,10 +34,15 @@
 #include "utils.h"
 
 rmode_t routing_mode = RMODE_ROUTER;
+fmode_t forwarding_mode = FMODE_INTERNAL;
+bmode_t broadcast_mode = BMODE_MST;
+bool decrement_ttl = false;
+bool directonly = false;
 bool priorityinheritance = false;
 int macexpire = 600;
 bool overwrite_mac = false;
 mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}};
+bool pcap = false;
 
 /* Sizes of various headers */
 
@@ -49,6 +55,12 @@ static const size_t icmp6_size = sizeof(struct icmp6_hdr);
 static const size_t ns_size = sizeof(struct nd_neighbor_solicit);
 static const size_t opt_size = sizeof(struct nd_opt_hdr);
 
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
+static struct event age_subnets_event;
+
 /* RFC 1071 */
 
 static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
@@ -72,26 +84,100 @@ static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
 static bool ratelimit(int frequency) {
 	static time_t lasttime = 0;
 	static int count = 0;
+	time_t now = time(NULL);
 	
 	if(lasttime == now) {
-		if(++count > frequency)
+		if(count >= frequency)
 			return true;
 	} else {
 		lasttime = now;
 		count = 0;
 	}
 
+	count++;
 	return false;
 }
 
 static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 	if(packet->len < length) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got too short packet from %s (%s)"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Got too short packet from %s (%s)", source->name, source->hostname);
 		return false;
 	} else
 		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))
+		return;
+
+	uint16_t mtu = source->mtu;
+	if(via != myself && via->mtu < mtu)
+		mtu = via->mtu;
+
+	/* Find TCP header */
+	int start = 0;
+	uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+	if(type == ETH_P_IP && packet->data[23] == 6)
+		start = 14 + (packet->data[14] & 0xf) * 4;
+	else if(type == ETH_P_IPV6 && packet->data[20] == 6)
+		start = 14 + 40;
+
+	if(!start || packet->len <= start + 20)
+		return;
+
+	/* Use data offset field to calculate length of options field */
+	int len = ((packet->data[start + 12] >> 4) - 5) * 4;
+
+	if(packet->len < start + 20 + len)
+		return;
+
+	/* Search for MSS option header */
+	for(int i = 0; i < len;) {
+		if(packet->data[start + 20 + i] == 0)
+			break;
+
+		if(packet->data[start + 20 + i] == 1) {
+			i++;
+			continue;
+		}
+
+		if(i > len - 2 || i > len - packet->data[start + 21 + i])
+			break;
+
+		if(packet->data[start + 20 + i] != 2) {
+			if(packet->data[start + 21 + i] < 2)
+				break;
+			i += packet->data[start + 21 + i];
+			continue;
+		}
+
+		if(packet->data[start + 21] != 4)
+			break;
+
+		/* Found it */
+		uint16_t oldmss = packet->data[start + 22 + i] << 8 | packet->data[start + 23 + i];
+		uint16_t newmss = mtu - start - 20;
+		uint16_t csum = packet->data[start + 16] << 8 | packet->data[start + 17];
+
+		if(oldmss <= newmss)
+			break;
+		
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Clamping MSS of packet from %s to %s to %d", source->name, via->name, newmss);
+
+		/* Update the MSS value and the checksum */
+		packet->data[start + 22 + i] = newmss >> 8;
+		packet->data[start + 23 + i] = newmss & 0xff;
+		csum ^= 0xffff;
+		csum -= oldmss;
+		csum += newmss;
+		csum ^= 0xffff;
+		packet->data[start + 16] = csum >> 8;
+		packet->data[start + 17] = csum & 0xff;
+		break;
+	}
+}
+
 static void swap_mac_addresses(vpn_packet_t *packet) {
 	mac_t tmp;
 	memcpy(&tmp, &packet->data[0], sizeof tmp);
@@ -99,62 +185,71 @@ static void swap_mac_addresses(vpn_packet_t *packet) {
 	memcpy(&packet->data[6], &tmp, sizeof tmp);
 }
 	
-static void learn_mac(mac_t *address) {
-	subnet_t *subnet;
-	avl_node_t *node;
-	connection_t *c;
+static void age_subnets(int fd, short events, void *data) {
+	bool left = false;
+	time_t now = time(NULL);
+
+	for(splay_node_t *node = myself->subnet_tree->head, *next; node; node = next) {
+		next = node->next;
+		subnet_t *s = node->data;
+		if(s->expires && s->expires < now) {
+			if(debug_level >= DEBUG_TRAFFIC) {
+				char netstr[MAXNETSTR];
+				if(net2str(netstr, sizeof netstr, s))
+					logger(DEBUG_TRAFFIC, LOG_INFO, "Subnet %s expired", netstr);
+			}
+
+			for(list_node_t *node = connection_list->head, *next; node; node = next) {
+				next = node->next;
+				connection_t *c = node->data;
+				if(c->status.active)
+					send_del_subnet(c, s);
+			}
+
+			subnet_del(myself, s);
+		} else {
+			if(s->expires)
+				left = true;
+		}
+	}
 
-	subnet = lookup_subnet_mac(address);
+	if(left)
+		event_add(&age_subnets_event, &(struct timeval){10, 0});
+}
+
+static void learn_mac(mac_t *address) {
+	subnet_t *subnet = lookup_subnet_mac(myself, address);
 
 	/* If we don't know this MAC address yet, store it */
 
 	if(!subnet) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, _("Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx"),
+		logger(DEBUG_TRAFFIC, LOG_INFO, "Learned new MAC address %hx:%hx:%hx:%hx:%hx:%hx",
 				   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;
-		subnet->expires = now + macexpire;
+		subnet->expires = time(NULL) + macexpire;
 		subnet->net.mac.address = *address;
+		subnet->weight = 10;
 		subnet_add(myself, subnet);
+		subnet_update(myself, subnet, true);
 
 		/* And tell all other tinc daemons it's our MAC */
 
-		for(node = connection_tree->head; node; node = node->next) {
-			c = node->data;
+		for(list_node_t *node = connection_list->head, *next; node; node = next) {
+			next = node->next;
+			connection_t *c = node->data;
 			if(c->status.active)
 				send_add_subnet(c, subnet);
 		}
-	}
-
-	if(subnet->expires)
-		subnet->expires = now + macexpire;
-}
-
-void age_subnets(void) {
-	subnet_t *s;
-	connection_t *c;
-	avl_node_t *node, *next, *node2;
-
-	for(node = myself->subnet_tree->head; node; node = next) {
-		next = node->next;
-		s = node->data;
-		if(s->expires && s->expires < now) {
-			ifdebug(TRAFFIC) {
-				char netstr[MAXNETSTR];
-				if(net2str(netstr, sizeof netstr, s))
-					logger(LOG_INFO, _("Subnet %s expired"), netstr);
-			}
 
-			for(node2 = connection_tree->head; node2; node2 = node2->next) {
-				c = node2->data;
-				if(c->status.active)
-					send_del_subnet(c, s);
-			}
-
-			subnet_del(myself, s);
-		}
+		if(!timeout_initialized(&age_subnets_event))
+			timeout_set(&age_subnets_event, age_subnets, NULL);
+		event_add(&age_subnets_event, &(struct timeval){10, 0});
+	} else {
+		if(subnet->expires)
+			subnet->expires = time(NULL) + macexpire;
 	}
 }
 
@@ -249,11 +344,11 @@ static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet) {
 	todo = ntohs(ip.ip_len) - ip_size;
 
 	if(ether_size + ip_size + todo != packet->len) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Length of packet (%d) doesn't match length in IPv4 header (%zd)"), packet->len, ether_size + ip_size + todo);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Length of packet (%d) doesn't match length in IPv4 header (%d)", packet->len, (int)(ether_size + ip_size + todo));
 		return;
 	}
 
-	ifdebug(TRAFFIC) logger(LOG_INFO, _("Fragmenting packet of %d bytes to %s (%s)"), packet->len, dest->name, dest->hostname);
+	logger(DEBUG_TRAFFIC, LOG_INFO, "Fragmenting packet of %d bytes to %s (%s)", packet->len, dest->name, dest->hostname);
 
 	offset = packet->data + ether_size + ip_size;
 	maxlen = (dest->mtu - ether_size - ip_size) & ~0x7;
@@ -290,7 +385,7 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_ipv4(&dest);
 
 	if(!subnet) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv4 destination address %d.%d.%d.%d"),
+		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],
@@ -302,22 +397,33 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 	
 	if(subnet->owner == source) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
 		return;
 	}
 
 	if(!subnet->owner->status.reachable)
-		route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+		return route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+		return route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_ANO);
 
 	if(priorityinheritance)
 		packet->priority = packet->data[15];
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+	if(via == source) {
+		logger(DEBUG_TRAFFIC, LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
+		return;
+	}
 	
-	if(via && packet->len > via->mtu && via != myself) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
+	if(directonly && subnet->owner != via)
+		return route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+
+	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(packet->data[20] & 0x40) {
-			packet->len = via->mtu;
+			packet->len = MAX(via->mtu, 590);
 			route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
 		} else {
 			fragment_ipv4_packet(via, packet);
@@ -326,6 +432,8 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
@@ -333,11 +441,11 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 	if(!checklength(source, packet, ether_size + ip_size))
 		return;
 
-	if(((packet->data[30] & 0xf0) == 0xe0) || (
+	if(broadcast_mode && (((packet->data[30] & 0xf0) == 0xe0) || (
 			packet->data[30] == 255 &&
 			packet->data[31] == 255 &&
 			packet->data[32] == 255 &&
-			packet->data[33] == 255))
+			packet->data[33] == 255)))
 		broadcast_packet(source, packet);
 	else
 		route_ipv4_unicast(source, packet);
@@ -407,7 +515,7 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
 
 	/* Generate checksum */
 	
-	checksum = inet_checksum(&pseudo, sizeof(pseudo), ~0);
+	checksum = inet_checksum(&pseudo, sizeof pseudo, ~0);
 	checksum = inet_checksum(&icmp6, icmp6_size, checksum);
 	checksum = inet_checksum(packet->data + ether_size + ip6_size + icmp6_size, ntohl(pseudo.length) - icmp6_size, checksum);
 
@@ -432,7 +540,7 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_ipv6(&dest);
 
 	if(!subnet) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown IPv6 destination address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
+		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]),
@@ -448,22 +556,35 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(subnet->owner == source) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
 		return;
 	}
 
 	if(!subnet->owner->status.reachable)
-		route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+		return route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+		return route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 	
-	if(via && packet->len > via->mtu && via != myself) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
-		packet->len = via->mtu;
+	if(via == source) {
+		logger(DEBUG_TRAFFIC, LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
+		return;
+	}
+	
+	if(directonly && subnet->owner != via)
+		return route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+
+	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);
+		packet->len = MAX(via->mtu, 1294);
 		route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
 		return;
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
@@ -490,7 +611,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 	has_opt = packet->len >= ether_size + ip6_size + ns_size + opt_size + ETH_ALEN;
 	
 	if(source != myself) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got neighbor solicitation request from %s (%s) while in router mode!"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Got neighbor solicitation request from %s (%s) while in router mode!", source->name, source->hostname);
 		return;
 	}
 
@@ -510,7 +631,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	if(ns.nd_ns_hdr.icmp6_type != ND_NEIGHBOR_SOLICIT ||
 	   (has_opt && opt.nd_opt_type != ND_OPT_SOURCE_LINKADDR)) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type neighbor solicitation request"));
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: received unknown type neighbor solicitation request");
 		return;
 	}
 
@@ -526,7 +647,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	/* 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);
@@ -534,7 +655,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(checksum) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: checksum error for neighbor solicitation request"));
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet: checksum error for neighbor solicitation request");
 		return;
 	}
 
@@ -543,7 +664,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_ipv6((ipv6_t *) &ns.nd_ns_target);
 
 	if(!subnet) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: neighbor solicitation request for unknown address %hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"),
+		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]),
@@ -589,7 +710,7 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 
 	/* 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);
@@ -617,7 +738,7 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(packet->data[38] == 255)
+	if(broadcast_mode && packet->data[38] == 255)
 		broadcast_packet(source, packet);
 	else
 		route_ipv6_unicast(source, packet);
@@ -634,7 +755,7 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 		return;
 
 	if(source != myself) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got ARP request from %s (%s) while in router mode!"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Got ARP request from %s (%s) while in router mode!", source->name, source->hostname);
 		return;
 	}
 
@@ -650,8 +771,8 @@ 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) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: received unknown type ARP 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;
 	}
 
@@ -660,7 +781,7 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_ipv4((ipv4_t *) &arp.arp_tpa);
 
 	if(!subnet) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet: ARP request for unknown address %d.%d.%d.%d"),
+		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]);
 		return;
@@ -674,9 +795,9 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);	/* copy destination address */
 	packet->data[ETH_ALEN * 2 - 1] ^= 0xFF;	/* mangle source address so it looks like it's not from us */
 
-	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, packet->data + ETH_ALEN, ETH_ALEN);	/* add fake source hard addr */
@@ -704,7 +825,7 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	/* Lookup destination address */
 
 	memcpy(&dest, &packet->data[0], sizeof dest);
-	subnet = lookup_subnet_mac(&dest);
+	subnet = lookup_subnet_mac(NULL, &dest);
 
 	if(!subnet) {
 		broadcast_packet(source, packet);
@@ -712,18 +833,24 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(subnet->owner == source) {
-		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Packet looping back to %s (%s)!"), source->name, source->hostname);
+		logger(DEBUG_TRAFFIC, LOG_WARNING, "Packet looping back to %s (%s)!", source->name, source->hostname);
 		return;
 	}
 
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+		return;
+
 	// Handle packets larger than PMTU
 
 	node_t *via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+	if(directonly && subnet->owner != via)
+		return;
 	
 	if(via && packet->len > via->mtu && via != myself) {
-		ifdebug(TRAFFIC) logger(LOG_INFO, _("Packet for %s (%s) length %d larger than MTU %d"), subnet->owner->name, subnet->owner->hostname, packet->len, via->mtu);
+		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);
 		uint16_t type = packet->data[12] << 8 | packet->data[13];
-		if(type == ETH_P_IP) {
+		if(type == ETH_P_IP && packet->len > 590) {
 			if(packet->data[20] & 0x40) {
 				packet->len = via->mtu;
 				route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
@@ -731,20 +858,98 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 				fragment_ipv4_packet(via, packet);
 			}
 			return;
-		} else if(type == ETH_P_IPV6) {
+		} else if(type == ETH_P_IPV6 && packet->len > 1294) {
 			packet->len = via->mtu;
 			route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
 			return;
 		}
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
+static void send_pcap(vpn_packet_t *packet) {
+	pcap = false;
+	for(list_node_t *node = connection_list->head, *next; node; node = next) {
+		next = node->next;
+		connection_t *c = node->data;
+		if(!c->status.pcap)
+			continue;
+
+		pcap = true;
+		int len = packet->len;
+		if(c->outmaclength && c->outmaclength < len)
+			len = c->outmaclength;
+
+		if(send_request(c, "%d %d %d", CONTROL, REQ_PCAP, len))
+			send_meta(c, (char *)packet->data, len);
+	}
+}
+
+static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
+	uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+	switch (type) {
+		case ETH_P_IP:
+			if(!checklength(source, packet, 14 + 32))
+				return false;
+
+			if(packet->data[22] < 1) {
+				if(packet->data[25] != IPPROTO_ICMP || packet->data[46] != ICMP_TIME_EXCEEDED)
+					route_ipv4_unreachable(source, packet, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
+				return false;
+			}
+
+			uint16_t old = packet->data[22] << 8 | packet->data[23];
+			packet->data[22]--;
+			uint16_t new = packet->data[22] << 8 | packet->data[23];
+
+			uint32_t checksum = packet->data[24] << 8 | packet->data[25];
+			checksum += old + (~new & 0xFFFF);
+			while(checksum >> 16)
+				checksum = (checksum & 0xFFFF) + (checksum >> 16);
+			packet->data[24] = checksum >> 8;
+			packet->data[25] = checksum & 0xff;
+
+			return true;
+
+		case ETH_P_IPV6:
+			if(!checklength(source, packet, 14 + 40))
+				return false;
+
+			if(packet->data[21] < 1) {
+				if(packet->data[20] != IPPROTO_ICMPV6 || packet->data[54] != ICMP6_TIME_EXCEEDED)
+					route_ipv6_unreachable(source, packet, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
+				return false;
+			}
+
+			packet->data[21]--;
+
+			return true;
+
+		default:
+			return true;
+	}
+}
+
 void route(node_t *source, vpn_packet_t *packet) {
+	if(pcap)
+		send_pcap(packet);
+
+	if(forwarding_mode == FMODE_KERNEL && source != myself) {
+		send_packet(myself, packet);
+		return;
+	}
+
 	if(!checklength(source, packet, ether_size))
 		return;
 
+	if(decrement_ttl && source != myself)
+		if(!do_decrement_ttl(source, packet))
+			return;
+
 	switch (routing_mode) {
 		case RMODE_ROUTER:
 			{
@@ -764,7 +969,7 @@ void route(node_t *source, vpn_packet_t *packet) {
 						break;
 
 					default:
-						ifdebug(TRAFFIC) logger(LOG_WARNING, _("Cannot route packet from %s (%s): unknown type %hx"), source->name, source->hostname, type);
+						logger(DEBUG_TRAFFIC, LOG_WARNING, "Cannot route packet from %s (%s): unknown type %hx", source->name, source->hostname, type);
 						break;
 				}
 			}