Commit c67b8555 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6566cd36

include/net/inet_timewait_sock.h

+1 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct inet_timewait_sock { 
				tw_flowlabel	: 20,

				tw_pad		: 2,	/* 2 bits hole */

				tw_tos		: 8;

	u32			tw_txhash;

	struct timer_list	tw_timer;

	struct inet_bind_bucket	*tw_tb;

};

net/ipv4/tcp_minisocks.c

+1 −0
Original line number Diff line number Diff line
@@ -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

net/ipv6/tcp_ipv6.c

+10 −3
Original line number Diff line number Diff line
@@ -883,9 +883,16 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 
		fl6.flowi6_oif = oif;

	}



	if (sk)

		mark = (sk->sk_state == TCP_TIME_WAIT) ?

			inet_twsk(sk)->tw_mark : sk->sk_mark;

	if (sk) {

		if (sk->sk_state == TCP_TIME_WAIT) {

			mark = inet_twsk(sk)->tw_mark;

			/* autoflowlabel relies on buff->hash */

			skb_set_hash(buff, inet_twsk(sk)->tw_txhash,

				     PKT_HASH_TYPE_L4);

		} else {

			mark = sk->sk_mark;

		}

	}

	fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;

	fl6.fl6_dport = t1->dest;

	fl6.fl6_sport = t1->source;

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