net/ipv6/sit.c: return unhandled skb to tunnel4_rcv

I found a problem using an IPv6 over IPv4 tunnel.  When CONFIG_IPV6_SIT
was enabled, the packets would be rejected as net/ipv6/sit.c was catching
all IPPROTO_IPV6 packets and returning an ICMP port unreachable error.

I think this patch fixes the problem cleanly.  I believe the code in
net/ipv4/tunnel4.c:tunnel4_rcv takes care of it properly if none of the
handlers claim the skb.

Signed-off-by: David McCullough <david_mccullough@mcafee.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index d6bfaec3bbbf..8c4d00c7cd2b 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -606,8 +606,9 @@ static int ipip6_rcv(struct sk_buff *skb)
                 return 0;
         }
 
-        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
+        /* no tunnel matched,  let upstream know, ipsec may handle it */
         rcu_read_unlock();
+        return 1;
 out:
         kfree_skb(skb);
         return 0;