[PATCH] net/ipv6: icmp: fix is_ineligible() to block errors for Redirect packets

[Sayooj K Karun]

RFC 4443 section 2.4(e.2) mandates that an ICMPv6 error message MUST NOT
be originated in response to an ICMPv6 Redirect message (type 137).

Add check for NDISC_REDIRECT (137) so that redirect packets become
ineligible and error packets are not generated for Redirect messages.

Signed-off-by: Sayooj K Karun <sayooj@xxxxxxxxxxx>
---
 net/ipv6/icmp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index efb23807a026..3fdb3a97dd8e 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -157,7 +157,8 @@ static bool is_ineligible(const struct sk_buff *skb)
 		 */
 		if (!tp && frag_off != 0)
 			return false;
-		else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
+		else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK) ||
+			 *tp == NDISC_REDIRECT)
 			return true;
 	}
 	return false;
-- 
2.53.0