tcp: directly drop skb in cookie check for ipv6

Like previous patch does, only moving skb drop logical code to
cookie_v6_check() for later refinement.

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/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 6b9c692788196d294fdf2b824c55a712e974970a..ea0d9954a29f2f140d12f093d16a32e1ee6de4c9 100644 (file)
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -177,6 +177,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
        struct sock *ret = sk;
        __u8 rcv_wscale;
        int full_space;
+       SKB_DR(reason);
 
        if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||
            !th->ack || th->rst)
@@ -256,10 +257,13 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
        ireq->ecn_ok &= cookie_ecn_ok(net, dst);
 
        ret = tcp_get_cookie_sock(sk, skb, req, dst);
+       if (!ret)
+               goto out_drop;
 out:
        return ret;
 out_free:
        reqsk_free(req);
 out_drop:
+       kfree_skb_reason(skb, reason);
        return NULL;
 }

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 57b25b1fc9d9d529e3c53778ef09b65b1ac4c9d5..0c180bb8187fa126dbffe59cae9f4b0c515fa79d 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1653,11 +1653,8 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
        if (sk->sk_state == TCP_LISTEN) {
                struct sock *nsk = tcp_v6_cookie_check(sk, skb);
 
-               if (!nsk)
-                       goto discard;
-
                if (nsk != sk) {
-                       if (tcp_child_process(sk, nsk, skb))
+                       if (nsk && tcp_child_process(sk, nsk, skb))
                                goto reset;
                        if (opt_skb)
                                __kfree_skb(opt_skb);