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: Petar Penkov <ppenkov@google.com>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c21e8a2..8892df6 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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;
        }