X-Git-Url: https://git.librecmc.org/?p=oweals%2Ftinc.git;a=blobdiff_plain;f=src%2Froute.c;h=a1254d80832491ee947e505c2c2050a9cd33e0fa;hp=5c69671ad30a7d55602569defe55db43eb970f9d;hb=a588f6febeca13edd038d78e42efb8aa9f16a444;hpb=43a6e786648fb666a9b7be8f05c8a173031c9110

diff --git a/src/route.c b/src/route.c
index 5c69671..a1254d8 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>
+                  2000-2014 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
@@ -33,6 +33,10 @@
 #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;
@@ -49,6 +53,10 @@ 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
+
 /* RFC 1071 */
 
 static uint16_t inet_checksum(void *data, int len, uint16_t prevsum) {
@@ -74,13 +82,14 @@ static bool ratelimit(int frequency) {
 	static int count = 0;
 	
 	if(lasttime == now) {
-		if(++count > frequency)
+		if(count >= frequency)
 			return true;
 	} else {
 		lasttime = now;
 		count = 0;
 	}
 
+	count++;
 	return false;
 }
 
@@ -92,6 +101,85 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 		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 = ether_size;
+	uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+	if(type == ETH_P_8021Q) {
+		start += 4;
+		type = packet->data[16] << 8 | packet->data[17];
+	}
+
+	if(type == ETH_P_IP && packet->data[start + 9] == 6)
+		start += (packet->data[start] & 0xf) * 4;
+	else if(type == ETH_P_IPV6 && packet->data[start + 6] == 6)
+		start += 40;
+	else
+		return;
+
+	if(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;
+		
+		ifdebug(TRAFFIC) logger(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);
@@ -104,12 +192,12 @@ static void learn_mac(mac_t *address) {
 	avl_node_t *node;
 	connection_t *c;
 
-	subnet = lookup_subnet_mac(address);
+	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",
+		ifdebug(TRAFFIC) logger(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]);
 
@@ -119,6 +207,7 @@ static void learn_mac(mac_t *address) {
 		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 */
 
@@ -141,7 +230,7 @@ void age_subnets(void) {
 	for(node = myself->subnet_tree->head; node; node = next) {
 		next = node->next;
 		s = node->data;
-		if(s->expires && s->expires < now) {
+		if(s->expires && s->expires <= now) {
 			ifdebug(TRAFFIC) {
 				char netstr[MAXNETSTR];
 				if(net2str(netstr, sizeof netstr, s))
@@ -154,6 +243,7 @@ void age_subnets(void) {
 					send_del_subnet(c, s);
 			}
 
+			subnet_update(myself, s, false);
 			subnet_del(myself, s);
 		}
 	}
@@ -161,7 +251,7 @@ void age_subnets(void) {
 
 /* RFC 792 */
 
-static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) {
+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};
 	
@@ -234,7 +324,7 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
 
 /* RFC 791 */
 
-static void fragment_ipv4_packet(node_t *dest, vpn_packet_t *packet) {
+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;
@@ -250,7 +340,7 @@ 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);
+		ifdebug(TRAFFIC) logger(LOG_WARNING, "Length of packet (%d) doesn't match length in IPv4 header (%d)", packet->len, (int)(ether_size + ip_size + todo));
 		return;
 	}
 
@@ -298,7 +388,7 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 				dest.x[2],
 				dest.x[3]);
 
-		route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
+		route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNKNOWN);
 		return;
 	}
 	
@@ -308,25 +398,38 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(!subnet->owner->status.reachable)
-		route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_UNREACH);
+
+	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(priorityinheritance)
 		packet->priority = packet->data[15];
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
+
+	if(via == source) {
+		ifdebug(TRAFFIC) logger(LOG_ERR, "Routing loop for packet from %s (%s)!", source->name, source->hostname);
+		return;
+	}
 	
-	if(via && packet->len > via->mtu && via != myself) {
+	if(directonly && subnet->owner != via)
+		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+
+	if(via && packet->len > MAX(via->mtu, 590) && 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(packet->data[20] & 0x40) {
-			packet->len = via->mtu;
-			route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+			packet->len = MAX(via->mtu, 590);
+			route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
 		} else {
-			fragment_ipv4_packet(via, packet);
+			fragment_ipv4_packet(via, packet, ether_size);
 		}
 
 		return;
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
@@ -334,11 +437,11 @@ 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);
@@ -346,7 +449,7 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 
 /* RFC 2463 */
 
-static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t type, uint8_t code) {
+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;	
@@ -444,7 +547,7 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 				ntohs(dest.x[6]),
 				ntohs(dest.x[7]));
 
-		route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR);
 		return;
 	}
 
@@ -454,17 +557,30 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(!subnet->owner->status.reachable)
-		route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+		return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOROUTE);
+
+	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);
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 	
-	if(via && packet->len > via->mtu && via != myself) {
+	if(via == source) {
+		ifdebug(TRAFFIC) logger(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, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+
+	if(via && packet->len > MAX(via->mtu, 1294) && 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;
-		route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+		packet->len = MAX(via->mtu, 1294);
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_PACKET_TOO_BIG, 0);
 		return;
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
@@ -618,7 +734,7 @@ 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);
@@ -705,7 +821,7 @@ 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);
@@ -717,35 +833,115 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
+	if(forwarding_mode == FMODE_OFF && source != myself && subnet->owner != myself)
+		return;
+
+	uint16_t type = packet->data[12] << 8 | packet->data[13];
+
+	if(priorityinheritance && type == ETH_P_IP && packet->len >= ether_size + ip_size)
+		packet->priority = packet->data[15];
+
 	// 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);
-		uint16_t type = packet->data[12] << 8 | packet->data[13];
-		if(type == ETH_P_IP) {
-			if(packet->data[20] & 0x40) {
+		length_t ethlen = 14;
+
+		if(type == ETH_P_8021Q) {
+			type = packet->data[16] << 8 | packet->data[17];
+			ethlen += 4;
+		}
+
+		if(type == ETH_P_IP && packet->len > 576 + ethlen) {
+			if(packet->data[6 + ethlen] & 0x40) {
 				packet->len = via->mtu;
-				route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+				route_ipv4_unreachable(source, packet, ethlen, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
 			} else {
-				fragment_ipv4_packet(via, packet);
+				fragment_ipv4_packet(via, packet, ethlen);
 			}
 			return;
-		} else if(type == ETH_P_IPV6) {
+		} else if(type == ETH_P_IPV6 && packet->len > 1280 + ethlen) {
 			packet->len = via->mtu;
-			route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+			route_ipv6_unreachable(source, packet, ethlen, ICMP6_PACKET_TOO_BIG, 0);
 			return;
 		}
 	}
 
+	clamp_mss(source, via, packet);
+ 
 	send_packet(subnet->owner, packet);
 }
 
+static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
+	uint16_t type = packet->data[12] << 8 | packet->data[13];
+	length_t ethlen = ether_size;
+
+	if(type == ETH_P_8021Q) {
+		type = packet->data[16] << 8 | packet->data[17];
+		ethlen += 4;
+	}
+
+	switch (type) {
+		case ETH_P_IP:
+			if(!checklength(source, packet, ethlen + ip_size))
+				return false;
+
+			if(packet->data[ethlen + 8] <= 1) {
+				if(packet->data[ethlen + 11] != IPPROTO_ICMP || packet->data[ethlen + 32] != ICMP_TIME_EXCEEDED)
+					route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
+				return false;
+			}
+
+			uint16_t old = packet->data[ethlen + 8] << 8 | packet->data[ethlen + 9];
+			packet->data[ethlen + 8]--;
+			uint16_t new = packet->data[ethlen + 8] << 8 | packet->data[ethlen + 9];
+
+			uint32_t checksum = packet->data[ethlen + 10] << 8 | packet->data[ethlen + 11];
+			checksum += old + (~new & 0xFFFF);
+			while(checksum >> 16)
+				checksum = (checksum & 0xFFFF) + (checksum >> 16);
+			packet->data[ethlen + 10] = checksum >> 8;
+			packet->data[ethlen + 11] = checksum & 0xff;
+
+			return true;
+
+		case ETH_P_IPV6:
+			if(!checklength(source, packet, ethlen + ip6_size))
+				return false;
+
+			if(packet->data[ethlen + 7] <= 1) {
+				if(packet->data[ethlen + 6] != IPPROTO_ICMPV6 || packet->data[ethlen + 40] != ICMP6_TIME_EXCEEDED)
+					route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
+				return false;
+			}
+
+			packet->data[ethlen + 7]--;
+
+			return true;
+
+		default:
+			return true;
+	}
+}
+
 void route(node_t *source, vpn_packet_t *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:
 			{