ip6_tunnel: respect ttl inherit for ip6tnl

man ip-tunnel ttl section says:
0 is a special value meaning that packets inherit the TTL value.

IPv4 tunnel respect this in ip_tunnel_xmit(), but IPv6 tunnel has not
implement it yet. To make IPv6 behave consistently with IP tunnel,
add ipv6 tunnel inherit support.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 5df2a58..419960b 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1188,7 +1188,15 @@ route_lookup:
                init_tel_txopt(&opt, encap_limit);
                ipv6_push_frag_opts(skb, &opt.ops, &proto);
        }
-       hop_limit = hop_limit ? : ip6_dst_hoplimit(dst);
+
+       if (hop_limit == 0) {
+               if (skb->protocol == htons(ETH_P_IP))
+                       hop_limit = ip_hdr(skb)->ttl;
+               else if (skb->protocol == htons(ETH_P_IPV6))
+                       hop_limit = ipv6_hdr(skb)->hop_limit;
+               else
+                       hop_limit = ip6_dst_hoplimit(dst);
+       }
 
        /* Calculate max headroom for all the headers and adjust
         * needed_headroom if necessary.