Remove net lock from TCP sysctl for keep alive.

Keep copies in seconds for the sysctl and update timer variables
atomically when they change. tcp_maxidle was historically calculated
in tcp_slowtimo

Remove net lock from TCP sysctl for keep alive.

Keep copies in seconds for the sysctl and update timer variables
atomically when they change. tcp_maxidle was historically calculated
in tcp_slowtimo() as the timers were called from there. Better
calculate maxidle when needed. tcp_timer_init() is useless, just
initialize data. While there make the names consistent.

input sthen@; OK mvs@

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Reference count the inpcb in TCP timers.

Switch from struct tcpcb to inpcb in the TCP timer argument. The
latter already has a reference counter. Increment it at timeout_add()
and decrement at tim

Reference count the inpcb in TCP timers.

Switch from struct tcpcb to inpcb in the TCP timer argument. The
latter already has a reference counter. Increment it at timeout_add()
and decrement at timeout_del() or when handler runs. The reaper
timeout is special as it does not need a reference, the inpcb is
already dead. Use special field t_timer_reaper instead of regular
TCP timeout and run it without reference or lock.

OK mvs@

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Fix whitespace.

Read more TCP sysctl variables atomically.

OK mvs@

Declare some global TCP variables constant.

OK mvs@

Run TCP timer without kernel lock.

TCP timers are protected by exclusive net lock. They may sleep to
grab it as they run in process context. There is no reason for
them to hold additional kernel l

Run TCP timer without kernel lock.

TCP timers are protected by exclusive net lock. They may sleep to
grab it as they run in process context. There is no reason for
them to hold additional kernel lock. Since we have MP safe timeouts
now, convert them by adding TIMEOUT_PROC and TIMEOUT_MPSAFE flag.

OK mvs@

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To avoid misunderstanding, keep variables for tcp keepalive in
milliseconds, which is the same unit of tcp_now(). However, keep the
unit of sysctl variables in seconds and convert their unit in
tcp_

To avoid misunderstanding, keep variables for tcp keepalive in
milliseconds, which is the same unit of tcp_now(). However, keep the
unit of sysctl variables in seconds and convert their unit in
tcp_sysctl(). Additionally revert TCPTV_SRTTDFLT back to 3 seconds,
which was mistakenly changed to 1.5 seconds by tcp_timer.h 1.19.

ok claudio

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Modify TCP receive buffer size auto scaling to use the smoothed RTT
(SRTT) instead of the timestamp option. Since the timestamp option is
disabled on some OSs (eg. Windows) or dropped by some
firewa

Modify TCP receive buffer size auto scaling to use the smoothed RTT
(SRTT) instead of the timestamp option. Since the timestamp option is
disabled on some OSs (eg. Windows) or dropped by some
firewalls/routers, in such a case the window size had been fixed at
16KB, this limits throughput at very low on high latency networks.
Also replace "tcp_now" from 2HZ tick counter to binuptime in
milliseconds to calculate the SRTT better.

tested by krw matthieu jmatthew dlg djm stu stsp
ok claudio

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Historically there were slow and fast tcp timeouts. That is why
the delack timer had a different implementation. Use the same
mechanism for all TCP timer.
OK mpi@ visa@

Historically TCP timeouts were implemented with pr_slowtimo and
pr_fasttimo. That is the reason why we have two timeout mechanisms
with complicated ticks calculation. Move the delay ACK timeout to

Historically TCP timeouts were implemented with pr_slowtimo and
pr_fasttimo. That is the reason why we have two timeout mechanisms
with complicated ticks calculation. Move the delay ACK timeout to
milliseconds and remove some ticks and hz mess from the others.
This makes it easier to see the actual values.
OK florian@ dhill@ dlg@

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There was a race in the TCP timers. As they may sleep to grab the
netlock, timers may still run after they have been disarmed. Deleting
the timeout is not sufficient to cancel them, but the code fr

There was a race in the TCP timers. As they may sleep to grab the
netlock, timers may still run after they have been disarmed. Deleting
the timeout is not sufficient to cancel them, but the code from 4.4
BSD is assuming this.
The solution is to add a flag for every timer to see whether it has
been armed or canceled. Remove the TF_DEAD check as tcp_canceltimers()
is called before the reaper timer is fired. Cancelation works
reliably now.
OK mpi@

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The TCP reaper timeout was still imlemented as soft timeout. So
it could run immediately and was not synchronized with the TCP
timeouts, although that was the intension when it was introduced
in rev

The TCP reaper timeout was still imlemented as soft timeout. So
it could run immediately and was not synchronized with the TCP
timeouts, although that was the intension when it was introduced
in revision 1.85. Convert the reaper to an ordinary TCP timeout
so it is scheduled on the same timeout thread after all timeouts
have finished. A net lock is not necessary as the process calling
tcp_close() will not access the tcpcb after arming the reaper
timeout.
OK mikeb@

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Convert timeouts that need a process context to timeout_set_proc(9).

The current reason is that rtalloc_mpath(9) inside ip_output() might
end up inserting a RTF_CLONED route and that require a write

Convert timeouts that need a process context to timeout_set_proc(9).

The current reason is that rtalloc_mpath(9) inside ip_output() might
end up inserting a RTF_CLONED route and that require a write lock.

ok kettenis@, bluhm@

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Add sysctl net.inet.tcp.always_keepalive, when this is set the system
behaves as if SO_KEEPALIVE was set on all TCP sockets, forcing keepalives
to be sent every net.inet.tcp.keepidle half-seconds.

I

Add sysctl net.inet.tcp.always_keepalive, when this is set the system
behaves as if SO_KEEPALIVE was set on all TCP sockets, forcing keepalives
to be sent every net.inet.tcp.keepidle half-seconds.

In conjunction with a keepidle value greatly reduced from the default,
this can be useful for keeping sessions open if you are stuck on a network
with short NAT or firewall timeouts.

Feedback from various people, ok henning@ claudio@

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fix macros up so they use the do { } while (/* CONSTCOND */ 0) idiom

ok deraadt@ otto@

some spelling fixes from Martynas Venckus

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

another const char * from David Hill

use timeout(9) to schedule TCP timers. this avoid traversing all
tcp connections during tcp_slowtimo. apdapted from thorpej@netbsd.org

remove tcp_fasttimo and convert delayed acks to the timeout(9) API instead.
adapated from netbsd. okay angelos@

typo

use macros to manage tcp timers; based on netbsd

Inclusion protection.

OpenBSD tags + some prototyping police

fix tuba after synbomb fixes