From a8a3a2c8ceb19bcb6c2c3ef0647c94d7d0624b7a Mon Sep 17 00:00:00 2001
From: "Vittorio Gambaletta (VittGam)" <github@vittgam.net>
Date: Thu, 3 Sep 2015 16:02:50 +0200
Subject: [PATCH] Fix DecrementTTL option.
The option was not actually working, as it could be seen on traceroute or mtr.
The problem is that it was checking if the TTL was < 1 (so equal to 0) before decrementing it.
This meant that a packet with a TTL of 1 was being sent with a TTL of 0 on the VPN, instead of being discarded with the ICMP error message.
Signed-off-by: Vittorio Gambaletta <openwrt@vittgam.net>
# Conflicts:
# src/route.c
---
src/route.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/route.c b/src/route.c
index 68a66492..d7c4c872 100644
--- a/src/route.c
+++ b/src/route.c
@@ -902,7 +902,7 @@ static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
if(!checklength(source, packet, ethlen + ip_size))
return false;
- if(DATA(packet)[ethlen + 8] < 1) {
+ if(DATA(packet)[ethlen + 8] <= 1) {
if(DATA(packet)[ethlen + 11] != IPPROTO_ICMP || DATA(packet)[ethlen + 32] != ICMP_TIME_EXCEEDED)
route_ipv4_unreachable(source, packet, ethlen, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL);
return false;
@@ -925,7 +925,7 @@ static bool do_decrement_ttl(node_t *source, vpn_packet_t *packet) {
if(!checklength(source, packet, ethlen + ip6_size))
return false;
- if(DATA(packet)[ethlen + 7] < 1) {
+ if(DATA(packet)[ethlen + 7] <= 1) {
if(DATA(packet)[ethlen + 6] != IPPROTO_ICMPV6 || DATA(packet)[ethlen + 40] != ICMP6_TIME_EXCEEDED)
route_ipv6_unreachable(source, packet, ethlen, ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_TRANSIT);
return false;
--
2.39.5