From 95a22caee396cef0bb2ca8fafdd82966a49367bb Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 1 Dec 2016 11:32:06 +0100 Subject: tcp: randomize tcp timestamp offsets for each connection jiffies based timestamps allow for easy inference of number of devices behind NAT translators and also makes tracking of hosts simpler. commit ceaa1fef65a7c2e ("tcp: adding a per-socket timestamp offset") added the main infrastructure that is needed for per-connection ts randomization, in particular writing/reading the on-wire tcp header format takes the offset into account so rest of stack can use normal tcp_time_stamp (jiffies). So only two items are left: - add a tsoffset for request sockets - extend the tcp isn generator to also return another 32bit number in addition to the ISN. Re-use of ISN generator also means timestamps are still monotonically increasing for same connection quadruple, i.e. PAWS will still work. Includes fixes from Eric Dumazet. Signed-off-by: Florian Westphal Acked-by: Eric Dumazet Acked-by: Yuchung Cheng Signed-off-by: David S. Miller --- include/linux/tcp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tcp.h') diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 00e0ee8f001f..734bab4c3bef 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -123,6 +123,7 @@ struct tcp_request_sock { u32 txhash; u32 rcv_isn; u32 snt_isn; + u32 ts_off; u32 last_oow_ack_time; /* last SYNACK */ u32 rcv_nxt; /* the ack # by SYNACK. For * FastOpen it's the seq# -- cgit v1.2.3