tcp: use inet6_csk_route_req() in tcp_v6_send_synack()

With the recent change (earlier in this patch series) to set
flowi6_oif to treq->iif in inet6_csk_route_req(), the dst lookup in
these two functions is now identical, so tcp_v6_send_synack() can now
just call inet6_csk_route_req(), to reduce code duplication and keep
things closer to the IPv4 side, which is structured this way.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 4e5fa5f6ec684e1661a094cc586c3b0f95d06cca..d1db0caefdcd0294041f6420b76cdcb31fb51e42 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -485,34 +485,17 @@ static int tcp_v6_send_synack(struct sock *sk,
        struct inet6_request_sock *treq = inet6_rsk(req);
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct sk_buff * skb;
-       struct ipv6_txoptions *opt = NULL;
-       struct in6_addr * final_p, final;
+       struct ipv6_txoptions *opt = np->opt;
        struct flowi6 fl6;
        struct dst_entry *dst;
-       int err;
-
-       memset(&fl6, 0, sizeof(fl6));
-       fl6.flowi6_proto = IPPROTO_TCP;
-       fl6.daddr = treq->rmt_addr;
-       fl6.saddr = treq->loc_addr;
-       fl6.flowlabel = 0;
-       fl6.flowi6_oif = treq->iif;
-       fl6.flowi6_mark = sk->sk_mark;
-       fl6.fl6_dport = inet_rsk(req)->rmt_port;
-       fl6.fl6_sport = inet_rsk(req)->loc_port;
-       security_req_classify_flow(req, flowi6_to_flowi(&fl6));
-
-       opt = np->opt;
-       final_p = fl6_update_dst(&fl6, opt, &final);
+       int err = -ENOMEM;
 
-       dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
-       if (IS_ERR(dst)) {
-               err = PTR_ERR(dst);
-               dst = NULL;
+       dst = inet6_csk_route_req(sk, &fl6, req);
+       if (!dst)
                goto done;
-       }
+
        skb = tcp_make_synack(sk, dst, req, rvp);
-       err = -ENOMEM;
+
        if (skb) {
                __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);