tcp: allow specifying a MSL for local communications

When setting the sysctl-variable net.inet.tcp.nolocaltimewait to 1,
which is the default, a TCP endpoint does not enter the TIME-WAIT state,
when

tcp: allow specifying a MSL for local communications

When setting the sysctl-variable net.inet.tcp.nolocaltimewait to 1,
which is the default, a TCP endpoint does not enter the TIME-WAIT state,
when the communication is local. This can result in sending
RST-segments without any error situation. By setting the
sysctl-variable net.inet.tcp.nolocaltimewait to 0, this does not
occur, and the behavior is compliant with the TCP specification.
But there is no reason to stay in the TIME-WAIT state for two times
the value of the sysctl-variable net.inet.tcp.msl, if the
communication is local. Therefore provide a separate sysctl-variable
net.inet.tcp.msl_local, which controls how long an TCP end-point
stays in the TIME-WAIT state, if the communication is local.
The default value is 10 ms.

Reviewed by: glebius, Peter Lei
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D50637

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tcp: cleanup timer initialisations

Use MSEC_2_TICKS() to make clearer, which values are used and to
ensure that the value stored is at least one tick. This also avoids
the need of some protection co

tcp: cleanup timer initialisations

Use MSEC_2_TICKS() to make clearer, which values are used and to
ensure that the value stored is at least one tick. This also avoids
the need of some protection code.

Reviewed by: glebius, cc
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D50840

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tcp: restrict the contents of tcp_timer.h to the kernel context

The header file contains only stuff relevant in the kernel context.

Reviewed by: glebius, rscheff, Peter Lei, imp
Sponsored by: Net

tcp: restrict the contents of tcp_timer.h to the kernel context

The header file contains only stuff relevant in the kernel context.

Reviewed by: glebius, rscheff, Peter Lei, imp
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D50912

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tcp: provide sysctl for the maximum retransmission timeout

Reviewed by: tuexen
Differential Revision: https://reviews.freebsd.org/D50891

tcp: remove TCPTV_TWTRUNC

It is not used anymore...

Reviewed by: rscheff, Peter Lei
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D50900

Revert "tcp: cleanup timer initialisations"

This reverts commit c13f4b1574da77f89ab57cfcc87fe8ad80f25263.
Using MSEC_2_TICKS() breaks compiling
contrib/bsnmp/snmp_mibII/mibII_tcp.c
since it includes

Revert "tcp: cleanup timer initialisations"

This reverts commit c13f4b1574da77f89ab57cfcc87fe8ad80f25263.
Using MSEC_2_TICKS() breaks compiling
contrib/bsnmp/snmp_mibII/mibII_tcp.c
since it includes tcp_timer.h in userland and MSEC_2_TICKS() is
only defined for kernel land.

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tcp: cleanup timer initialisations

Use MSEC_2_TICKS() to make clearer, which values are used and to
ensure that the value stored is at least one tick.
This also avoids the need of some protection co

tcp: cleanup timer initialisations

Use MSEC_2_TICKS() to make clearer, which values are used and to
ensure that the value stored is at least one tick.
This also avoids the need of some protection code.

Reviewed by: cc, glebius
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D50840

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sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl s

sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

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sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

tcp: rearrange enum and remove unused variable

Rearrange the enum tt_which such that TT_REXMIT is 0. This allows
an extension of the BBLog event RTO in a backwards compatible way.
Remove tcptimers,

tcp: rearrange enum and remove unused variable

Rearrange the enum tt_which such that TT_REXMIT is 0. This allows
an extension of the BBLog event RTO in a backwards compatible way.
Remove tcptimers, which was only used in trpt, a utility removed
from the source tree recently.

Reviewed by: glebius@, guest-ccui@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D38547

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tcp: use single locked callout per tcpcb for the TCP timers

Use only one callout structure per tcpcb that is responsible for handling
all five TCP timeouts. Use locked version of callout, of course

tcp: use single locked callout per tcpcb for the TCP timers

Use only one callout structure per tcpcb that is responsible for handling
all five TCP timeouts. Use locked version of callout, of course. The
callout function tcp_timer_enter() chooses soonest timer and executes it
with lock held. Unless the timer reports that the tcpcb has been freed,
the callout is rescheduled for next soonest timer, if there is any.

With single callout per tcpcb on connection teardown we should be able
to fully stop the callout and immediately free it, avoiding use of
callout_async_drain(). There is one gotcha here: callout_stop() can
actually touch our memory when a rare race condition happens. See
comment above tcp_timer_stop(). Synchronous stop of the callout makes
tcp_discardcb() the single entry point for tcpcb destructor, merging the
tcp_freecb() to the end of the function.

While here, also remove lots of lingering checks in the beginning of
TCP timer functions. With a locked callout they are unnecessary.

While here, clean unused parts of timer KPI for the pluggable TCP stacks.

While here, remove TCPDEBUG from tcp_timer.c, as this allows for more
simplification of TCP timers. The TCPDEBUG is scheduled for removal.

Move the DTrace probes in timers to the beginning of a function, where
a tcpcb is always existing.

Discussed with: rrs, tuexen, rscheff (the TCP part of the diff)
Reviewed by: hselasky, kib, mav (the callout part)
Differential revision: https://reviews.freebsd.org/D37321

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tcp: remove tcp_timer_suspend()

It was a temporary code added together with RACK to fight against
TCP timer races.

tcp: embed inpcb into tcpcb

For the TCP protocol inpcb storage specify allocation size that would
provide space to most of the data a TCP connection needs, embedding
into struct tcpcb several struct

tcp: embed inpcb into tcpcb

For the TCP protocol inpcb storage specify allocation size that would
provide space to most of the data a TCP connection needs, embedding
into struct tcpcb several structures, that previously were allocated
separately.

The most import one is the inpcb itself. With embedding we can provide
strong guarantee that with a valid TCP inpcb the tcpcb is always valid
and vice versa. Also we reduce number of allocs/frees per connection.
The embedded inpcb is placed in the beginning of the struct tcpcb,
since in_pcballoc() requires that. However, later we may want to move
it around for cache line efficiency, and this can be done with a little
effort. The new intotcpcb() macro is ready for such move.

The congestion algorithm data, the TCP timers and osd(9) data are
also embedded into tcpcb, and temprorary struct tcpcb_mem goes away.
There was no extra allocation here, but we went through extra pointer
every time we accessed this data.

One interesting side effect is that now TCP data is allocated from
SMR-protected zone. Potentially this allows the TCP stacks or other
TCP related modules to utilize that for their own synchronization.

Large part of the change was done with sed script:

s/tp->ccv->/tp->t_ccv./g
s/tp->ccv/\&tp->t_ccv/g
s/tp->cc_algo/tp->t_cc/g
s/tp->t_timers->tt_/tp->tt_/g
s/CCV\(ccv, osd\)/\&CCV(ccv, t_osd)/g

Dependency side effect is that code that needs to know struct tcpcb
should also know struct inpcb, that added several <netinet/in_pcb.h>.

Differential revision: https://reviews.freebsd.org/D37127

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tcp: remove tcptw, the compressed timewait state structure

The memory savings the tcptw brought back in 2003 (see 340c35de6a2) no
longer justify the complexity required to maintain it. For longer
e

tcp: remove tcptw, the compressed timewait state structure

The memory savings the tcptw brought back in 2003 (see 340c35de6a2) no
longer justify the complexity required to maintain it. For longer
explanation please check out the email [1].

Surpisingly through almost 20 years the TCP stack functionality of
handling the TIME_WAIT state with a normal tcpcb did not bitrot. The
existing tcp_input() properly handles a tcpcb in TCPS_TIME_WAIT state,
which is confirmed by the packetdrill tcp-testsuite [2].

This change just removes tcptw and leaves INP_TIMEWAIT. The flag will
be removed in a separate commit. This makes it easier to review and
possibly debug the changes.

[1] https://lists.freebsd.org/archives/freebsd-net/2022-January/001206.html
[2] https://github.com/freebsd-net/tcp-testsuite

Differential revision: https://reviews.freebsd.org/D36398

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tcp_timers: provide tcp_timer_drop() and tcp_timer_close()

Two functions to call tcp_drop() and tcp_close() from a callout context.
Garbage collect tcp_inpinfo_lock_del(), it has a single use now.

tcp_timers: provide tcp_timer_drop() and tcp_timer_close()

Two functions to call tcp_drop() and tcp_close() from a callout context.
Garbage collect tcp_inpinfo_lock_del(), it has a single use now.

Differential revision: https://reviews.freebsd.org/D36397

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Tcp progress timeout

Rack has had the ability to timeout connections that just sit idle automatically. This
feature of course is off by default and requires the user set it on (though the socket opt

Tcp progress timeout

Rack has had the ability to timeout connections that just sit idle automatically. This
feature of course is off by default and requires the user set it on (though the socket option
has been missing in tcp_usrreq.c). Lets get the progress timeout fully supported in
the base stack as well as rack.

Reviewed by: tuexen
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D36716

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tcp: virtualise net.inet.tcp.msl sysctl.

VNET teardown waits 2*MSL (60 seconds by default) before expiring
tcp PCBs. These PCBs holds references to nexthops, which, in turn,
reference ifnets. This

tcp: virtualise net.inet.tcp.msl sysctl.

VNET teardown waits 2*MSL (60 seconds by default) before expiring
tcp PCBs. These PCBs holds references to nexthops, which, in turn,
reference ifnets. This chain results in VNET interfaces being destroyed
and moved to default VNET only after 60 seconds.
Allow tcp_msl to be set in jail by virtualising net.inet.tcp.msl sysctl,
permitting more predictable VNET tests outcomes.

MFC after: 1 week
Reviewed by: glebius
Differential Revision: https://reviews.freebsd.org/D33270

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Add tcp_freecb() - single place to free tcpcb.

Until this change there were two places where we would free tcpcb -
tcp_discardcb() in case if all timers are drained and tcp_timer_discard()
otherwise

Add tcp_freecb() - single place to free tcpcb.

Until this change there were two places where we would free tcpcb -
tcp_discardcb() in case if all timers are drained and tcp_timer_discard()
otherwise. They were pretty much copy-n-paste, except that in the
default case we would run tcp_hc_update(). Merge this into single
function tcp_freecb() and move new short version of tcp_timer_discard()
to tcp_timer.c and make it static.

Reviewed by: rrs, hselasky
Differential revision: https://reviews.freebsd.org/D32965

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kern: net: remove TCP_LINGERTIME

TCP_LINGERTIME can be traced back to BSD 4.4 Lite and perhaps beyond, in
exactly the same form that it appears here modulo slightly different
context. It used to be

kern: net: remove TCP_LINGERTIME

TCP_LINGERTIME can be traced back to BSD 4.4 Lite and perhaps beyond, in
exactly the same form that it appears here modulo slightly different
context. It used to be the case that there was a single pr_usrreq
method with requests dispatched to it; these exact two lines appeared in
tcp_usrreq's PRU_ATTACH handling.

The only purpose of this that I can find is to cause surprising behavior
on accepted connections. Newly-created sockets will never hit these
paths as one cannot set SO_LINGER prior to socket(2). If SO_LINGER is
set on a listening socket and inherited, one would expect the timeout to
be inherited rather than changed arbitrarily like this -- noting that
SO_LINGER is nonsense on a listening socket beyond inheritance, since
they cannot be 'connected' by definition.

Neither Illumos nor Linux reset the timer like this based on testing and
inspection of Illumos, and testing of Linux.

Reviewed by: rscheff, tuexen
Differential Revision: https://reviews.freebsd.org/D28265

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Reduce default TCP delayed ACK timeout to 40ms.

Reviewed by: kbowling, tuexen
Approved by: tuexen (mentor)
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebs

Reduce default TCP delayed ACK timeout to 40ms.

Reviewed by: kbowling, tuexen
Approved by: tuexen (mentor)
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D23281

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Merge ^/head r357662 through r357854.

White space cleanup -- remove trailing tab's or spaces
from any line.

Sponsored by: Netflix Inc.

vnet: virtualise more network stack sysctls.

Virtualise tcp_always_keepalive, TCP and UDP log_in_vain. All three are
set in the netoptions startup script, which we would love to run for VNETs
as we

vnet: virtualise more network stack sysctls.

Virtualise tcp_always_keepalive, TCP and UDP log_in_vain. All three are
set in the netoptions startup script, which we would love to run for VNETs
as well [1].

While virtualising the log_in_vain sysctls seems pointles at first for as
long as the kernel message buffer is not virtualised, it at least allows
an administrator to debug the base system or an individual jail if needed
without turning the logging on for all jails running on a system.

PR: 243193 [1]
MFC after: 2 weeks

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MFHead@r345677

Add sysctl variable net.inet.tcp.rexmit_initial for setting RTO.Initial
used by TCP.

Reviewed by: rrs@, 0mp@
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D19355