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Commit 96511278 authored by Petar Penkov's avatar Petar Penkov Committed by Alexei Starovoitov
Browse files

tcp: tcp_syn_flood_action read port from socket 



This allows us to call this function before an SKB has been
allocated.

Signed-off-by: default avatarPetar Penkov <ppenkov@google.com>
Reviewed-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent d3406913

net/ipv4/tcp_input.c

+3 −5
Original line number Diff line number Diff line
@@ -6422,9 +6422,7 @@ EXPORT_SYMBOL(inet_reqsk_alloc); 
/*

 * Return true if a syncookie should be sent

 */

static bool tcp_syn_flood_action(const struct sock *sk,

				 const struct sk_buff *skb,

				 const char *proto)

static bool tcp_syn_flood_action(const struct sock *sk, const char *proto)

{

	struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;

	const char *msg = "Dropping request";
@@ -6444,7 +6442,7 @@ static bool tcp_syn_flood_action(const struct sock *sk, 
	    net->ipv4.sysctl_tcp_syncookies != 2 &&

	    xchg(&queue->synflood_warned, 1) == 0)

		net_info_ratelimited("%s: Possible SYN flooding on port %d. %s.  Check SNMP counters.\n",

				     proto, ntohs(tcp_hdr(skb)->dest), msg);

				     proto, sk->sk_num, msg);



	return want_cookie;

}
@@ -6487,7 +6485,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, 
	 */

	if ((net->ipv4.sysctl_tcp_syncookies == 2 ||

	     inet_csk_reqsk_queue_is_full(sk)) && !isn) {

		want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name);

		want_cookie = tcp_syn_flood_action(sk, rsk_ops->slab_name);

		if (!want_cookie)

			goto drop;

	}