summaryrefslogtreecommitdiff
path: root/net/ipv4
diff options
context:
space:
mode:
authorEnke Chen <enchen@paloaltonetworks.com>2021-01-22 22:13:06 +0300
committerJakub Kicinski <kuba@kernel.org>2021-01-24 06:32:51 +0300
commit344db93ae3ee69fc137bd6ed89a8ff1bf5b0db08 (patch)
tree9550bba9e51fe81198e0e36c626a4d762e0487f5 /net/ipv4
parent3a30537cee233fb7da302491b28c832247d89bbe (diff)
downloadlinux-344db93ae3ee69fc137bd6ed89a8ff1bf5b0db08.tar.xz
tcp: make TCP_USER_TIMEOUT accurate for zero window probes
The TCP_USER_TIMEOUT is checked by the 0-window probe timer. As the timer has backoff with a max interval of about two minutes, the actual timeout for TCP_USER_TIMEOUT can be off by up to two minutes. In this patch the TCP_USER_TIMEOUT is made more accurate by taking it into account when computing the timer value for the 0-window probes. This patch is similar to and builds on top of the one that made TCP_USER_TIMEOUT accurate for RTOs in commit b701a99e431d ("tcp: Add tcp_clamp_rto_to_user_timeout() helper to improve accuracy"). Fixes: 9721e709fa68 ("tcp: simplify window probe aborting on USER_TIMEOUT") Signed-off-by: Enke Chen <enchen@paloaltonetworks.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20210122191306.GA99540@localhost.localdomain Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c4
-rw-r--r--net/ipv4/tcp_output.c2
-rw-r--r--net/ipv4/tcp_timer.c18
3 files changed, 22 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a7dfca0a38cd..55c6fd6b5d13 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3392,8 +3392,8 @@ static void tcp_ack_probe(struct sock *sk)
} else {
unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX);
- tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
- when, TCP_RTO_MAX);
+ when = tcp_clamp_probe0_to_user_timeout(sk, when);
+ tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, when, TCP_RTO_MAX);
}
}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ab458697881e..8478cf749821 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -4099,6 +4099,8 @@ void tcp_send_probe0(struct sock *sk)
*/
timeout = TCP_RESOURCE_PROBE_INTERVAL;
}
+
+ timeout = tcp_clamp_probe0_to_user_timeout(sk, timeout);
tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, timeout, TCP_RTO_MAX);
}
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index faa92948441b..4ef08079ccfa 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -40,6 +40,24 @@ static u32 tcp_clamp_rto_to_user_timeout(const struct sock *sk)
return min_t(u32, icsk->icsk_rto, msecs_to_jiffies(remaining));
}
+u32 tcp_clamp_probe0_to_user_timeout(const struct sock *sk, u32 when)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ u32 remaining;
+ s32 elapsed;
+
+ if (!icsk->icsk_user_timeout || !icsk->icsk_probes_tstamp)
+ return when;
+
+ elapsed = tcp_jiffies32 - icsk->icsk_probes_tstamp;
+ if (unlikely(elapsed < 0))
+ elapsed = 0;
+ remaining = msecs_to_jiffies(icsk->icsk_user_timeout) - elapsed;
+ remaining = max_t(u32, remaining, TCP_TIMEOUT_MIN);
+
+ return min_t(u32, remaining, when);
+}
+
/**
* tcp_write_err() - close socket and save error info
* @sk: The socket the error has appeared on.