Commit 65be4393 authored by Jason Xing's avatar Jason Xing Committed by David S. Miller
Browse files

tcp: directly drop skb in cookie check for ipv4 



Only move the skb drop from tcp_v4_do_rcv() to cookie_v4_check() itself,
no other changes made. It can help us refine the specific drop reasons
later.

Signed-off-by: default avatarJason Xing <kernelxing@tencent.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 48e4704a

net/ipv4/syncookies.c

+4 −0
Original line number Diff line number Diff line
@@ -408,6 +408,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) 
	struct rtable *rt;

	__u8 rcv_wscale;

	int full_space;

	SKB_DR(reason);



	if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||

	    !th->ack || th->rst)
@@ -477,10 +478,13 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) 
	 */

	if (ret)

		inet_sk(ret)->cork.fl.u.ip4 = fl4;

	else

		goto out_drop;

out:

	return ret;

out_free:

	reqsk_free(req);

out_drop:

	kfree_skb_reason(skb, reason);

	return NULL;

}

net/ipv4/tcp_ipv4.c

+1 −1
Original line number Diff line number Diff line
@@ -1915,7 +1915,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) 
		struct sock *nsk = tcp_v4_cookie_check(sk, skb);



		if (!nsk)

			goto discard;

			return 0;

		if (nsk != sk) {

			if (tcp_child_process(sk, nsk, skb)) {

				rsk = nsk;