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Commit a9f11f96 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: fix wraparound issue in tcp_lp 



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>
parent ddc665a4

net/ipv4/tcp_lp.c

+4 −2
Original line number Diff line number Diff line
@@ -264,13 +264,15 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample) 
{

	struct tcp_sock *tp = tcp_sk(sk);

	struct lp *lp = inet_csk_ca(sk);

	u32 delta;



	if (sample->rtt_us > 0)

		tcp_lp_rtt_sample(sk, sample->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))