X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Froute.c;h=32be4dec404f06c2fffe6e53ef7c699343d064d0;hp=0b2d22eb55ca0c3f189391252d6baedd786ac07b;hb=3fba80174dbe29bcfe0d121a2a1d2e61be5ee57b;hpb=fba1c85f44edfc56c19d35332b1eb825179a8bb6

diff --git a/src/route.c b/src/route.c
index 0b2d22eb..32be4dec 100644
--- a/src/route.c
+++ b/src/route.c
@@ -36,10 +36,12 @@
 
 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;
+bool broadcast = true;
 mac_t mymac = {{0xFE, 0xFD, 0, 0, 0, 0}};
 bool pcap = false;
 
@@ -439,11 +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 && (((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);
@@ -731,7 +733,7 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet) {
 		return;
 	}
 
-	if(packet->data[38] == 255)
+	if(broadcast && packet->data[38] == 255)
 		broadcast_packet(source, packet);
 	else
 		route_ipv6_unicast(source, packet);
@@ -821,7 +823,8 @@ static void route_mac(node_t *source, vpn_packet_t *packet) {
 	subnet = lookup_subnet_mac(NULL, &dest);
 
 	if(!subnet) {
-		broadcast_packet(source, packet);
+		if(broadcast)
+			broadcast_packet(source, packet);
 		return;
 	}
 
@@ -876,6 +879,50 @@ static void send_pcap(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];
+
+	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(pcap)
 		send_pcap(packet);
@@ -888,6 +935,10 @@ 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:
 			{