ipv6: tcp: send consistent autoflowlabel in TIME_WAIT state

In case autoflowlabel is in action, skb_get_hash_flowi6()
derives a non zero skb->hash to the flowlabel.

If skb->hash is zero, a flow dissection is performed.

Since all TCP skbs sent from ESTABLISH state inherit their
skb->hash from sk->sk_txhash, we better keep a copy
of sk->sk_txhash into the TIME_WAIT socket.

After this patch, ACK or RST packets sent on behalf of
a TIME_WAIT socket have the flowlabel that was previously
used by the flow.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 7c35731816e2..11011e8386dc 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -283,6 +283,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
                         tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
                         tw->tw_tclass = np->tclass;
                         tw->tw_flowlabel = be32_to_cpu(np->flow_label & IPV6_FLOWLABEL_MASK);
+                        tw->tw_txhash = sk->sk_txhash;
                         tw->tw_ipv6only = sk->sk_ipv6only;
                 }
 #endif