tcp: provide skb->hash to synack packets

In commit b73c3d0e4f ("net: Save TX flow hash in sock and set in skbuf
on xmit"), Tom provided a l4 hash to most outgoing TCP packets.

We'd like to provide one as well for SYNACK packets, so that all packets
of a given flow share same txhash, to later enable bonding driver to
also use skb->hash to perform slave selection.

Note that a SYNACK retransmit shuffles the tx hash, as Tom did
in commit 265f94ff54 ("net: Recompute sk_txhash on negative routing
advice") for established sockets.

This has nice effect making TCP flows resilient to some kind of black
holes, even at connection establish phase.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This commit is contained in:

Eric Dumazet

2015-09-15 15:24:20 -07:00

committed by

David S. Miller

parent bbe8373138

commit 58d607d3e5

6 changed files with 14 additions and 6 deletions

									
										net/ipv4/tcp_input.c
									
		+1
		
												View File
												
				@@ -6228,6 +6228,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,

					}

					tcp_rsk(req)->snt_isn = isn;

					tcp_rsk(req)->txhash = net_tx_rndhash();

					tcp_openreq_init_rwin(req, sk, dst);

					fastopen = !want_cookie &&

						   tcp_try_fastopen(sk, skb, req, &foc, dst);