X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=9e9f9d041997752d52f6adb0e724a3a5618a3983;hp=664fed89fbd102edb543b637ed7148edaa2009d9;hb=ea415ccc1690d6e5864a7500977b181e5c8faafe;hpb=40d91ff619a6ea24a2a35c9d934bcc6bace27e24

diff --git a/src/route.c b/src/route.c
index 664fed89..9e9f9d04 100644
--- a/src/route.c
+++ b/src/route.c
@@ -33,6 +33,9 @@
 #include "utils.h"
 
 rmode_t routing_mode = RMODE_ROUTER;
+fmode_t forwarding_mode = FMODE_INTERNAL;
+bool decrement_ttl = true;
+bool directonly = false;
 bool priorityinheritance = false;
 int macexpire = 600;
 bool overwrite_mac = false;
@@ -48,7 +51,10 @@ static const size_t ip6_size = sizeof(struct ip6_hdr);
 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);
-#define max(a, b) ((a) > (b) ? (a) : (b))
+
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
 
 /* RFC 1071 */
 
@@ -94,9 +100,13 @@ static bool checklength(node_t *source, vpn_packet_t *packet, length_t length) {
 }
 
 static void clamp_mss(const node_t *source, const node_t *via, vpn_packet_t *packet) {
-	if(!via || via == myself || !(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)
+		mtu = via->mtu;
+
 	/* Find TCP header */
 	int start = 0;
 	uint16_t type = packet->data[12] << 8 | packet->data[13];
@@ -140,7 +150,7 @@ 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 = via->mtu - start - 20;
+		uint16_t newmss = mtu - start - 20;
 		uint16_t csum = packet->data[start + 16] << 8 | packet->data[start + 17];
 
 		if(oldmss <= newmss)
@@ -211,7 +221,7 @@ 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))
@@ -379,17 +389,23 @@ 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, 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 && packet->len > max(via->mtu, 590) && via != myself) {
+	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) {
 		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);
+			packet->len = MAX(via->mtu, 590);
 			route_ipv4_unreachable(source, packet, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED);
 		} else {
 			fragment_ipv4_packet(via, packet);
@@ -527,13 +543,19 @@ 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, 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 > max(via->mtu, 1294) && via != myself) {
+	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) {
 		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);
+		packet->len = MAX(via->mtu, 1294);
 		route_ipv6_unreachable(source, packet, ICMP6_PACKET_TOO_BIG, 0);
 		return;
 	}
@@ -792,9 +814,15 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 		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);
@@ -819,10 +847,63 @@ static void route_mac(node_t *source, vpn_packet_t *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];
+
+	switch (type) {
+		case ETH_P_IP:
+			if(!checklength(source, packet, 14 + 32))
+				return false;
+
+			if(packet->data[22] < 1) {
+				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) {
+				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(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:
 			{