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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 7990f4939e8d..df7b13f0e5e0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4361,6 +4361,23 @@ EXPORT_SYMBOL(tcp_do_parse_auth_options);
* up to bandwidth of 18Gigabit/sec. 8) ]
*/
+/* Estimates max number of increments of remote peer TSval in
+ * a replay window (based on our current RTO estimation).
+ */
+static u32 tcp_tsval_replay(const struct sock *sk)
+{
+ /* If we use usec TS resolution,
+ * then expect the remote peer to use the same resolution.
+ */
+ if (tcp_sk(sk)->tcp_usec_ts)
+ return inet_csk(sk)->icsk_rto * (USEC_PER_SEC / HZ);
+
+ /* RFC 7323 recommends a TSval clock between 1ms and 1sec.
+ * We know that some OS (including old linux) can use 1200 Hz.
+ */
+ return inet_csk(sk)->icsk_rto * 1200 / HZ;
+}
+
static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
@@ -4368,7 +4385,7 @@ static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
u32 seq = TCP_SKB_CB(skb)->seq;
u32 ack = TCP_SKB_CB(skb)->ack_seq;
- return (/* 1. Pure ACK with correct sequence number. */
+ return /* 1. Pure ACK with correct sequence number. */
(th->ack && seq == TCP_SKB_CB(skb)->end_seq && seq == tp->rcv_nxt) &&
/* 2. ... and duplicate ACK. */
@@ -4378,7 +4395,8 @@ static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
!tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) &&
/* 4. ... and sits in replay window. */
- (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <= (inet_csk(sk)->icsk_rto * 1024) / HZ);
+ (s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <=
+ tcp_tsval_replay(sk);
}
static inline bool tcp_paws_discard(const struct sock *sk,