tcp: use drop reasons in cookie check for ipv6

Like what I did to ipv4 mode, refine this part: adding more drop
reasons for better tracing.

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 ea0d9954a29f2f140d12f093d16a32e1ee6de4c9..8bad0a44a0a6c593b5fcc327e8ae6a5f106c8794 100644 (file)
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -190,16 +190,20 @@ struct sock *cookie_v6_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);
 
        ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
        ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 
-       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;
+       }
 
        if (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
            np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
@@ -236,8 +240,10 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
                security_req_classify_flow(req, flowi6_to_flowi_common(&fl6));
 
                dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p);
-               if (IS_ERR(dst))
+               if (IS_ERR(dst)) {
+                       SKB_DR_SET(reason, IP_OUTNOROUTES);
                        goto out_free;
+               }
        }
 
        req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
@@ -257,8 +263,10 @@ 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)
+       if (!ret) {
+               SKB_DR_SET(reason, NO_SOCKET);
                goto out_drop;
+       }
 out:
        return ret;
 out_free: