TCP v6 spends a good amount of time rebuilding a fresh fl6 at each transmit in inet6_csk_xmit()/inet6_csk_route_socket(). TCP v4 caches the information in inet->cork.fl.u.ip4 instead. This patch is a first step converting IPv6 to the same strategy: Before this patch inet6_sk_rebuild_header() only validated/rebuilt a dst. Automatic variable @fl6 content was lost. After this patch inet6_sk_rebuild_header() also initializes inet->cork.fl.u.ip6, which can be reused in the future. This makes inet6_sk_rebuild_header() very similar to inet_sk_rebuild_header(). Also remove the EXPORT_SYMBOL_GPL(), inet6_sk_rebuild_header() is not called from any module. Signed-off-by: Eric Dumazet --- CC: Matthieu Baerts --- net/ipv6/af_inet6.c | 57 +++++++++++++++++++++------------------------ 1 file changed, 27 insertions(+), 30 deletions(-) diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index bd29840659f34b5754a182303d2871c5f884dfce..0476dbc8edb2b8273fd337b15c8196e9597753ef 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -824,45 +824,42 @@ EXPORT_SYMBOL(inet6_unregister_protosw); int inet6_sk_rebuild_header(struct sock *sk) { struct ipv6_pinfo *np = inet6_sk(sk); + struct inet_sock *inet = inet_sk(sk); + struct in6_addr *final_p, final; struct dst_entry *dst; + struct flowi6 *fl6; dst = __sk_dst_check(sk, np->dst_cookie); + if (dst) + return 0; + + fl6 = &inet->cork.fl.u.ip6; + memset(fl6, 0, sizeof(*fl6)); + fl6->flowi6_proto = sk->sk_protocol; + fl6->daddr = sk->sk_v6_daddr; + fl6->saddr = np->saddr; + fl6->flowlabel = np->flow_label; + fl6->flowi6_oif = sk->sk_bound_dev_if; + fl6->flowi6_mark = sk->sk_mark; + fl6->fl6_dport = inet->inet_dport; + fl6->fl6_sport = inet->inet_sport; + fl6->flowi6_uid = sk_uid(sk); + security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); - if (!dst) { - struct inet_sock *inet = inet_sk(sk); - struct in6_addr *final_p, final; - struct flowi6 fl6; - - memset(&fl6, 0, sizeof(fl6)); - fl6.flowi6_proto = sk->sk_protocol; - fl6.daddr = sk->sk_v6_daddr; - fl6.saddr = np->saddr; - fl6.flowlabel = np->flow_label; - fl6.flowi6_oif = sk->sk_bound_dev_if; - fl6.flowi6_mark = sk->sk_mark; - fl6.fl6_dport = inet->inet_dport; - fl6.fl6_sport = inet->inet_sport; - fl6.flowi6_uid = sk_uid(sk); - security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6)); - - rcu_read_lock(); - final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), - &final); - rcu_read_unlock(); - - dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p); - if (IS_ERR(dst)) { - sk->sk_route_caps = 0; - WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst)); - return PTR_ERR(dst); - } + rcu_read_lock(); + final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final); + rcu_read_unlock(); - ip6_dst_store(sk, dst, false, false); + dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); + if (IS_ERR(dst)) { + sk->sk_route_caps = 0; + WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst)); + return PTR_ERR(dst); } + ip6_dst_store(sk, dst, false, false); return 0; } -EXPORT_SYMBOL_GPL(inet6_sk_rebuild_header); bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb, const struct inet6_skb_parm *opt) -- 2.53.0.rc2.204.g2597b5adb4-goog