X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=6415f0edcf8351eaa67bbc8cebc32045f286a43e;hp=3d7b1df1e426ad36d7c3105352abdd23899bd79f;hb=496f775568873bb769e48ceb644b15ab9f150d62;hpb=92203bdbcb1af4a52c7ca9d0e1a271168435c905

diff --git a/src/route.c b/src/route.c
index 3d7b1df1..6415f0ed 100644
--- a/src/route.c
+++ b/src/route.c
@@ -55,6 +55,8 @@ 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
@@ -250,6 +252,14 @@ static void learn_mac(mac_t *address) {
 	}
 }
 
+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, length_t ether_size, uint8_t type, uint8_t code) {
@@ -259,7 +269,6 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_
 	struct in_addr ip_src;
 	struct in_addr ip_dst;
 	uint32_t oldlen;
-	int sockfd;
 
 	if(ratelimit(3))
 		return;
@@ -279,21 +288,23 @@ static void route_ipv4_unreachable(node_t *source, vpn_packet_t *packet, length_
 
 	/* Try to reply with an IP address assigned to the local machine */
 
-	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))) {
+	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;
-			socklen_t addrlen = sizeof(addr);
-			if (!getsockname(sockfd, (struct sockaddr*) &addr, &addrlen) && addrlen <= sizeof(addr)) {
-				ip_dst = addr.sin_addr;
+			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);
 		}
-		close(sockfd);
 	}
 
 	oldlen = packet->len - ether_size;
@@ -418,7 +429,7 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if (!subnet->owner) {
-		broadcast_packet(source, packet);
+		broadcast_packet_helper(source, packet);
 		return;
 	}
 
@@ -433,6 +444,10 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet) {
 	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(decrement_ttl && source != myself && subnet->owner != myself)
+		if(!do_decrement_ttl(source, packet))
+			return;
+
 	if(priorityinheritance)
 		packet->priority = DATA(packet)[15];
 
@@ -469,7 +484,6 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_
 	struct ip6_hdr ip6;
 	struct icmp6_hdr icmp6 = {0};
 	uint16_t checksum;	
-	int sockfd;
 
 	struct {
 		struct in6_addr ip6_src;        /* source address */
@@ -496,21 +510,23 @@ static void route_ipv6_unreachable(node_t *source, vpn_packet_t *packet, length_
 
 	/* Try to reply with an IP address assigned to the local machine */
 
-	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))) {
+	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;
-			socklen_t addrlen = sizeof(addr);
-			if (!getsockname(sockfd, (struct sockaddr*) &addr, &addrlen) && addrlen <= sizeof(addr)) {
-				pseudo.ip6_src = addr.sin6_addr;
+			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);
 		}
-		close(sockfd);
 	}
 
 	pseudo.length = packet->len - ether_size;
@@ -598,7 +614,7 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 	}
 
 	if (!subnet->owner) {
-		broadcast_packet(source, packet);
+		broadcast_packet_helper(source, packet);
 		return;
 	}
 
@@ -613,6 +629,10 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 	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(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;
 
 	if(via == source) {
@@ -729,6 +749,10 @@ 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(DATA(packet), DATA(packet) + ETH_ALEN, ETH_ALEN); /* copy destination address */
@@ -824,6 +848,10 @@ 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(&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);                 /* ... */
@@ -858,7 +886,7 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_mac(NULL, &dest);
 
 	if(!subnet || !subnet->owner) {
-		broadcast_packet(source, packet);
+		broadcast_packet_helper(source, packet);
 		return;
 	}
 
@@ -870,6 +898,10 @@ 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 = DATA(packet)[12] << 8 | DATA(packet)[13];
 
 	if(priorityinheritance && type == ETH_P_IP && packet->len >= ether_size + ip_size)
@@ -992,10 +1024,6 @@ 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;
-
 	uint16_t type = DATA(packet)[12] << 8 | DATA(packet)[13];
 
 	switch (routing_mode) {
@@ -1024,7 +1052,7 @@ void route(node_t *source, vpn_packet_t *packet) {
 			break;
 
 		case RMODE_HUB:
-			broadcast_packet(source, packet);
+			broadcast_packet_helper(source, packet);
 			break;
 	}
 }