syncookies: avoid unneeded tcp header flag double check
caller: if (!th->rst && !th->syn && th->ack)
callee: if (!th->ack)
make the caller only check for !syn (common for 3whs), and move
the !rst / ack test to the callee.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 1238370..9fcb3ec 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -174,7 +174,7 @@
struct dst_entry *dst;
__u8 rcv_wscale;
- if (!sysctl_tcp_syncookies || !th->ack)
+ if (!sysctl_tcp_syncookies || !th->ack || th->rst)
goto out;
if (tcp_synq_no_recent_overflow(sk) ||