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authorFlorian Westphal <fw@strlen.de>2016-12-01 13:32:06 +0300
committerDavid S. Miller <davem@davemloft.net>2016-12-02 20:49:59 +0300
commit95a22caee396cef0bb2ca8fafdd82966a49367bb (patch)
treeba58ca9c85a73dc887096d8123d199b3d28a705c /net/ipv4/syncookies.c
parent7df5358d4707c6f0a26266d3a4dd97fd353947e2 (diff)
downloadlinux-95a22caee396cef0bb2ca8fafdd82966a49367bb.tar.xz
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 <fw@strlen.de> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/syncookies.c')
-rw-r--r--net/ipv4/syncookies.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 0dc6286272aa..3e88467d70ee 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -334,6 +334,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
treq = tcp_rsk(req);
treq->rcv_isn = ntohl(th->seq) - 1;
treq->snt_isn = cookie;
+ treq->ts_off = 0;
req->mss = mss;
ireq->ir_num = ntohs(th->dest);
ireq->ir_rmt_port = th->source;