ipv6: Early TCP socket demux

This is the IPv6 missing bits for infrastructure added in commit
41063e9dd1195 (ipv4: Early TCP socket demux.)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 0 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f49476e2d884..221224e72507 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1674,6 +1674,43 @@ do_time_wait:
         goto discard_it;
 }
 
+static void tcp_v6_early_demux(struct sk_buff *skb)
+{
+        const struct ipv6hdr *hdr;
+        const struct tcphdr *th;
+        struct sock *sk;
+
+        if (skb->pkt_type != PACKET_HOST)
+                return;
+
+        if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
+                return;
+
+        hdr = ipv6_hdr(skb);
+        th = tcp_hdr(skb);
+
+        if (th->doff < sizeof(struct tcphdr) / 4)
+                return;
+
+        sk = __inet6_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
+                                        &hdr->saddr, th->source,
+                                        &hdr->daddr, ntohs(th->dest),
+                                        inet6_iif(skb));
+        if (sk) {
+                skb->sk = sk;
+                skb->destructor = sock_edemux;
+                if (sk->sk_state != TCP_TIME_WAIT) {
+                        struct dst_entry *dst = sk->sk_rx_dst;
+                        struct inet_sock *icsk = inet_sk(sk);
+                        if (dst)
+                                dst = dst_check(dst, 0);
+                        if (dst &&
+                            icsk->rx_dst_ifindex == inet6_iif(skb))
+                                skb_dst_set_noref(skb, dst);
+                }
+        }
+}
+
 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
         .twsk_unique    = tcp_twsk_unique,
@@ -1984,6 +2021,7 @@ struct proto tcpv6_prot = {
 };
 
 static const struct inet6_protocol tcpv6_protocol = {
+        .early_demux    =       tcp_v6_early_demux,
         .handler        =       tcp_v6_rcv,
         .err_handler    =       tcp_v6_err,
         .gso_send_check =       tcp_v6_gso_send_check,