Commit ce5dde39 authored by Eric Dumazet's avatar Eric Dumazet Committed by Ben Hutchings

tcp: fix wraparound issue in tcp_lp

commit a9f11f96 upstream.

Be careful when comparing tcp_time_stamp to some u32 quantity,
otherwise result can be surprising.

Fixes: 7c106d7e ("[TCP]: TCP Low Priority congestion control")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent c58462a5
......@@ -264,13 +264,15 @@ static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, s32 rtt_us)
{
struct tcp_sock *tp = tcp_sk(sk);
struct lp *lp = inet_csk_ca(sk);
u32 delta;
if (rtt_us > 0)
tcp_lp_rtt_sample(sk, rtt_us);
/* calc inference */
if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
lp->inference = 3 * (tcp_time_stamp - tp->rx_opt.rcv_tsecr);
delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
if ((s32)delta > 0)
lp->inference = 3 * delta;
/* test if within inference */
if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
......
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