X-Git-Url: https://git.librecmc.org/?p=oweals%2Ftinc.git;a=blobdiff_plain;f=src%2Froute.c;h=1b539aa1df60cbb6b89838ac3686069f88433428;hp=051deffbc3adf2e42ee968726f1925988248296a;hb=225e403c82f3ad20870ad8e77208723a1b6bcb0c;hpb=4712d8f92e63e86e835ffb624d6399343ee568ea

diff --git a/src/route.c b/src/route.c
index 051deff..1b539aa 100644
--- a/src/route.c
+++ b/src/route.c
@@ -1,7 +1,7 @@
 /*
     route.c -- routing
     Copyright (C) 2000-2005 Ivo Timmermans,
-                  2000-2012 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
@@ -34,12 +34,12 @@
 
 rmode_t routing_mode = RMODE_ROUTER;
 fmode_t forwarding_mode = FMODE_INTERNAL;
-bool decrement_ttl = true;
+bmode_t broadcast_mode = BMODE_MST;
+bool decrement_ttl = false;
 bool directonly = false;
 bool priorityinheritance = false;
 int macexpire = 600;
 bool overwrite_mac = false;
-bool broadcast = true;
 mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}};
 
 /* Sizes of various headers */
@@ -53,6 +53,8 @@ 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);
 
+static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet);
+
 #ifndef MAX
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #endif
@@ -110,15 +112,22 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		mtu = via->mtu;
 
 	/* Find TCP header */
-	int start = 0;
+	int start = ether_size;
 	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(type == ETH_P_8021Q) {
+		start += 4;
+		type = packet->data[16] << 8 | packet->data[17];
+	}
 
-	if(!start || packet->len <= start + 20)
+	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 */
@@ -153,7 +162,7 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		/* 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];
+		uint32_t csum = packet->data[start + 16] << 8 | packet->data[start + 17];
 
 		if(oldmss <= newmss)
 			break;
@@ -164,11 +173,13 @@ static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *pac
 		packet->data[start + 22 + i] = newmss >> 8;
 		packet->data[start + 23 + i] = newmss & 0xff;
 		csum ^= 0xffff;
-		csum -= oldmss;
+		csum += oldmss ^ 0xffff;
 		csum += newmss;
+		csum = (csum & 0xffff) + (csum >> 16);
+		csum += csum >> 16;
 		csum ^= 0xffff;
 		packet->data[start + 16] = csum >> 8;
-		packet->data[start + 17] = csum & 0xff;
+		packet->data[start + 17] = csum;
 		break;
 	}
 }
@@ -190,7 +201,7 @@ static void learn_mac(mac_t *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]);
 
@@ -242,9 +253,17 @@ void age_subnets(void) {
 	}
 }
 
+static void broadcast_packet_helper(node_t *source, vpn_packet_t *packet) {
+	if(decrement_ttl && source != myself)
+		if(!do_decrement_ttl(source, packet))
+			return;
+
+	broadcast_packet(source, packet);
+}
+
 /* 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};
 	
@@ -268,6 +287,27 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
 	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) && addrlen <= sizeof(addr)) {
+					ip_dst = addr.sin_addr;
+				}
+			}
+			close(sockfd);
+		}
+	}
+
 	oldlen = packet->len - ether_size;
 
 	if(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
@@ -317,7 +357,7 @@ 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;
@@ -333,7 +373,7 @@ 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;
 	}
 
@@ -381,7 +421,7 @@ 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;
 	}
 	
@@ -391,10 +431,14 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(!subnet->owner->status.reachable)
-		return 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, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+		return route_ipv4_unreachable(source, packet, ether_size, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+
+	if(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet))
+			return;
 
 	if(priorityinheritance)
 		packet->priority = packet->data[15];
@@ -407,15 +451,15 @@ static void route_ipv4_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 	
 	if(directonly && subnet->owner != via)
-		return route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_NET_ANO);
+		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 = MAX(via->mtu, 590);
-			route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
+			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;
@@ -430,19 +474,19 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 	if(!checklength(source, packet, ether_size + ip_size))
 		return;
 
-	if(broadcast && (((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)))
-		broadcast_packet(source, packet);
+		broadcast_packet_helper(source, packet);
 	else
 		route_ipv4_unicast(source, 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;	
@@ -470,6 +514,27 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, uint8_t
 	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) && addrlen <= sizeof(addr)) {
+					pseudo.ip6_src = addr.sin6_addr;
+				}
+			}
+			close(sockfd);
+		}
+	}
+
 	pseudo.length = packet->len - ether_size;
 
 	if(type == ICMP6_PACKET_TOO_BIG)
@@ -540,7 +605,7 @@ 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;
 	}
 
@@ -550,10 +615,14 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if(!subnet->owner->status.reachable)
-		return 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, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+		return route_ipv6_unreachable(source, packet, ether_size, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+
+	if(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet))
+			return;
 
 	via = (subnet->owner->via == myself) ? subnet->owner->nexthop : subnet->owner->via;
 	
@@ -563,12 +632,12 @@ static void route_ipv6_unicast(node_t *source, vpn_packet_t *packet) {
 	}
 	
 	if(directonly && subnet->owner != via)
-		return route_ipv6_unreachable(source, packet, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADMIN);
+		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 = MAX(via->mtu, 1294);
-		route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
+		route_ipv6_unreachable(source, packet, ether_size, ICMP6_PACKET_TOO_BIG, 0);
 		return;
 	}
 
@@ -671,6 +740,10 @@ static void route_neighborsol(node_t *source, vpn_packet_t *packet) {
 	if(subnet->owner == myself)
 		return;					/* silently ignore */
 
+	if(decrement_ttl)
+		if(!do_decrement_ttl(source, packet))
+			return;
+
 	/* Create neighbor advertation reply */
 
 	memcpy(packet->data, packet->data + ETH_ALEN, ETH_ALEN);	/* copy destination address */
@@ -727,8 +800,8 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(broadcast && packet->data[38] == 255)
-		broadcast_packet(source, packet);
+	if(broadcast_mode && packet->data[38] == 255)
+		broadcast_packet_helper(source, packet);
 	else
 		route_ipv6_unicast(source, packet);
 }
@@ -781,6 +854,10 @@ static void route_arp(node_t *source, vpn_packet_t *packet) {
 	if(subnet->owner == myself)
 		return;					/* silently ignore */
 
+	if(decrement_ttl)
+		if(!do_decrement_ttl(source, packet))
+			return;
+
 	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 */
 
@@ -817,8 +894,7 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_mac(NULL, &dest);
 
 	if(!subnet) {
-		if(broadcast)
-			broadcast_packet(source, packet);
+		broadcast_packet_helper(source, packet);
 		return;
 	}
 
@@ -830,6 +906,15 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	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 = 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;
@@ -839,18 +924,24 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	
 	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 && packet->len > 590) {
-			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 && packet->len > 1294) {
+		} 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;
 		}
 	}
@@ -862,42 +953,48 @@ static void route_mac(node_t *source, vpn_packet_t *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, 14 + 32))
+			if(!checklength(source, packet, ethlen + ip_size))
 				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);
+			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[22] << 8 | packet->data[23];
-			packet->data[22]--;
-			uint16_t new = packet->data[22] << 8 | packet->data[23];
+			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[24] << 8 | packet->data[25];
+			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[24] = checksum >> 8;
-			packet->data[25] = checksum & 0xff;
+			packet->data[ethlen + 10] = checksum >> 8;
+			packet->data[ethlen + 11] = checksum & 0xff;
 
 			return true;
 
 		case ETH_P_IPV6:
-			if(!checklength(source, packet, 14 + 40))
+			if(!checklength(source, packet, ethlen + ip6_size))
 				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);
+			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[21]--;
+			packet->data[ethlen + 7]--;
 
 			return true;
 
@@ -915,10 +1012,6 @@ void route(node_t *source, vpn_packet_t *packet) {
 	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:
 			{
@@ -949,7 +1042,7 @@ void route(node_t *source, vpn_packet_t *packet) {
 			break;
 
 		case RMODE_HUB:
-			broadcast_packet(source, packet);
+			broadcast_packet_helper(source, packet);
 			break;
 	}
 }