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authorEric Dumazet <edumazet@google.com>2017-05-01 15:29:48 -0700
committerDavid S. Miller <davem@davemloft.net>2017-05-02 15:07:02 -0400
commita9f11f963a546fea9144f6a6d1a307e814a387e7 (patch)
treef0b2d91346ba97af27e4b5ba3cdaf8f4127d02f7 /net/ipv4
parentddc665a4bb4b728b4e6ecec8db1b64efa9184b9c (diff)
tcp: fix wraparound issue in tcp_lp
Be careful when comparing tcp_time_stamp to some u32 quantity, otherwise result can be surprising. Fixes: 7c106d7e782b ("[TCP]: TCP Low Priority congestion control") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_lp.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index 046fd3910873..d6fb6c067af4 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -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))