From: Eric Dumazet <eduma...@google.com>
We now have proper per-listener but also per network namespace counters
for SYN packets that might be dropped.
We replace the kfree_skb() by consume_skb() to be drop monitor [1]
friendly, and remove an obsolete comment.
FastOpen SYN packets can carry payload in them just fine.
[1] perf record -a -g -e skb:kfree_skb sleep 1; perf report
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
net/ipv4/tcp_input.c | 19 +------------------
1 file changed, 1 insertion(+), 18 deletions(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 90e0d9256b74..ab674cd99827 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5813,24 +5813,7 @@ int tcp_rcv_state_process(struct sock *sk, struct
sk_buff *skb)
if (icsk->icsk_af_ops->conn_request(sk, skb) < 0)
return 1;
- /* Now we have several options: In theory there is
- * nothing else in the frame. KA9Q has an option to
- * send data with the syn, BSD accepts data with the
- * syn up to the [to be] advertised window and
- * Solaris 2.1 gives you a protocol error. For now
- * we just ignore it, that fits the spec precisely
- * and avoids incompatibilities. It would be nice in
- * future to drop through and process the data.
- *
- * Now that TTCP is starting to be used we ought to
- * queue this data.
- * But, this leaves one open to an easy denial of
- * service attack, and SYN cookies can't defend
- * against this problem. So, we drop the data
- * in the interest of security over speed unless
- * it's still in use.
- */
- kfree_skb(skb);
+ consume_skb(skb);
return 0;
}
goto discard;
