tcp: md5: increment sk_drops on syn_recv state

TCP MD5 mismatches do increment sk_drops counter in all states but
SYN_RECV.

This is very unlikely to happen in the real world, but worth adding
to help diagnostics.

We increase the parent (listener) sk_drops.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index e0f46439e391..ac0ed7bda406 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1409,6 +1409,7 @@ process:
                 sk = req->rsk_listener;
                 tcp_v6_fill_cb(skb, hdr, th);
                 if (tcp_v6_inbound_md5_hash(sk, skb)) {
+                        sk_drops_add(sk, skb);
                         reqsk_put(req);
                         goto discard_it;
                 }