tcp: use drop reasons in cookie check for ipv4

Now it's time to use the prepared definitions to refine this part.
Four reasons used might enough for now, I think.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 38f331da6677f5cbb3f9f275ef539a535dfe5d42..7972ad3d7c73af68d6149ca76f6d12ddf881f3a2 100644 (file)
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -421,8 +421,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
                if (IS_ERR(req))
                        goto out;
        }
-       if (!req)
+       if (!req) {
+               SKB_DR_SET(reason, NO_SOCKET);
                goto out_drop;
+       }
 
        ireq = inet_rsk(req);
 
@@ -434,8 +436,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
         */
        RCU_INIT_POINTER(ireq->ireq_opt, tcp_v4_save_options(net, skb));
 
-       if (security_inet_conn_request(sk, skb, req))
+       if (security_inet_conn_request(sk, skb, req)) {
+               SKB_DR_SET(reason, SECURITY_HOOK);
                goto out_free;
+       }
 
        tcp_ao_syncookie(sk, skb, req, AF_INET);
 
@@ -452,8 +456,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
                           ireq->ir_loc_addr, th->source, th->dest, sk->sk_uid);
        security_req_classify_flow(req, flowi4_to_flowi_common(&fl4));
        rt = ip_route_output_key(net, &fl4);
-       if (IS_ERR(rt))
+       if (IS_ERR(rt)) {
+               SKB_DR_SET(reason, IP_OUTNOROUTES);
                goto out_free;
+       }
 
        /* Try to redo what tcp_v4_send_synack did. */
        req->rsk_window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW);
@@ -476,10 +482,11 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
        /* ip_queue_xmit() depends on our flow being setup
         * Normal sockets get it right from inet_csk_route_child_sock()
         */
-       if (ret)
-               inet_sk(ret)->cork.fl.u.ip4 = fl4;
-       else
+       if (!ret) {
+               SKB_DR_SET(reason, NO_SOCKET);
                goto out_drop;
+       }
+       inet_sk(ret)->cork.fl.u.ip4 = fl4;
 out:
        return ret;
 out_free: