tcp: don't store VNET in every tcpcb, take it from the inpcbinfo

Reviewed by: rscheff
Differential revision: https://reviews.freebsd.org/D37125

tcp: provide macros to access inpcb and socket from a tcpcb

There should be no functional changes with this commit.

Reviewed by: rscheff
Differential revision: https://reviews.freebsd.org/D37123

tcp: allow packets to be marked as ECT1 instead of ECT0

This adds the capability for a modular congestion control
to select which variant of ECN-capable-transport it wants to use
when sending out el

tcp: allow packets to be marked as ECT1 instead of ECT0

This adds the capability for a modular congestion control
to select which variant of ECN-capable-transport it wants to use
when sending out elegible segments. As an initial CC to utilize
this, DCTCP was selected.

Event: IETF 115 Hackathon
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D24869

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tcp: make tcp_packets_this_ack() only visible in kernel scope

tcp: add conservative d.cep accounting algorithm

Accurate ECN asks to conservatively estimate, when the
ACE counter may have wrapped due to a single ACK covering a larger
number of segments. This is

tcp: add conservative d.cep accounting algorithm

Accurate ECN asks to conservatively estimate, when the
ACE counter may have wrapped due to a single ACK covering a larger
number of segments. This is described in Annex A.2 of the
accurate-ecn draft.

Event: IETF 115 Hackathon
Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D37281

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tcp: make tcp_handle_wakeup() static and robust

It is called only from tcp_input() and always has valid parameter.

Reviewed by: rscheff, tuexen
Differential revision: https://reviews.freebsd.org/D

tcp: make tcp_handle_wakeup() static and robust

It is called only from tcp_input() and always has valid parameter.

Reviewed by: rscheff, tuexen
Differential revision: https://reviews.freebsd.org/D37115

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tcp: ECN preparations for ECN++, AccECN (tcp_respond)

tcp_respond is another function to build a tcp control packet
quickly. With ECN++ and AccECN, both the IP ECN header, and
the TCP ECN flags are

tcp: ECN preparations for ECN++, AccECN (tcp_respond)

tcp_respond is another function to build a tcp control packet
quickly. With ECN++ and AccECN, both the IP ECN header, and
the TCP ECN flags are supposed to reflect the correct state.

Also ensure that on receiving multiple ECN SYN-ACKs, the
responses triggered will reflect the latest state.

Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D36973

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tcp: style the struct tcpcb definition

- Use C99 types uintXX_t instead of u_intXX_t.
- Try to make space/tab usage a little bit more consistent.
- Shorten comments to fit into 80 chars.

Not a func

tcp: style the struct tcpcb definition

- Use C99 types uintXX_t instead of u_intXX_t.
- Try to make space/tab usage a little bit more consistent.
- Shorten comments to fit into 80 chars.

Not a functional change, just making future changes easier to read.

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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 idle reduce does not work for a server.

TCP has an idle-reduce feature that allows a connection to reduce its
cwnd after it has been idle more than an RTT. This feature only works
for a sending

tcp idle reduce does not work for a server.

TCP has an idle-reduce feature that allows a connection to reduce its
cwnd after it has been idle more than an RTT. This feature only works
for a sending side connection. It does this by at output checking the
idle time (t_rcvtime vs ticks) to see if its more than the RTO timeout.

The problem comes if you are a web server. You get a request and
then send out all the data.. then go idle. The next time you would
send is in response to a request from the peer asking for more data.
But the thing is you updated t_rcvtime when the request came in so
you never reduce.

The fix is to do the idle reduce check also on inbound.

Reviewed by: tuexen, rscheff
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D36721

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tcp: make tcp_drop_syn_sent() static

netinet*: de-void control input IP protocol methods

After decoupling of protosw(9) and IP wire protocols in 78b1fc05b205 for
IPv4 we got vector ip_ctlprotox[] that is executed only and only from
icm

netinet*: de-void control input IP protocol methods

After decoupling of protosw(9) and IP wire protocols in 78b1fc05b205 for
IPv4 we got vector ip_ctlprotox[] that is executed only and only from
icmp_input() and respectively for IPv6 we got ip6_ctlprotox[] executed
only and only from icmp6_input(). This allows to use protocol specific
argument types in these methods instead of struct sockaddr and void.

Reviewed by: melifaro
Differential revision: https://reviews.freebsd.org/D36727

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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 rack does not work properly with cubic.

Right now if you use rack with cubic (the new default cc) you will have
improper results. This is because rack uses different variables than
the base stac

TCP rack does not work properly with cubic.

Right now if you use rack with cubic (the new default cc) you will have
improper results. This is because rack uses different variables than
the base stack (or bbr) and thus tcp_compute_pipe() always returns
so that cubic will choose a 30% backoff not the 50% backoff it should
when it is newreno compatibility mode. The fix is to allow a stack (rack)
to override its own compute_pipe.

Reviewed by: tuexen, rscheff
Sponsored by: Netflix Inc
Differential Revision: https://reviews.freebsd.org/D36711

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tcp: fix simultaneous open and refine e80062a2d43

- The soisconnected() call on transition from SYN_RCVD to ESTABLISHED
is also necessary for a half-synchronized connection. Fix that
just setti

tcp: fix simultaneous open and refine e80062a2d43

- The soisconnected() call on transition from SYN_RCVD to ESTABLISHED
is also necessary for a half-synchronized connection. Fix that
just setting the flag, when we transfer SYN-SENT -> SYN-RECEIVED.
- Provide a comment that explains at what conditions the call to
soisconnected() is necessary.
- Hence mechanically rename the TF_INCQUEUE flag to TF_SONOTCONN.
- Extend the change to the BBR and RACK stacks.

Note: the interaction between the accept_filter(9) and the socket layer
is not fully consistent, yet. For most accept filters this call to
soisconnected() will not move the connection from the incomplete queue
to the complete. The move would happen only when the filter has received
the desired data, and soisconnected() would be called once again from
sorwakeup(). Ideally, we should mark socket as connected only there,
and leave the soisconnected() from SYN_RCVD->ESTABLISHED only for the
simultaneous open case. However, this doesn't yet work.

Reviewed by: rscheff, tuexen, rrs
Differential revision: https://reviews.freebsd.org/D36641

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tcpcb: fix tabulation count in i4012ef7754c and abbreviate "packets"

This lines up comments to the rest of the file. Abbreviation
helps to fit in to 80 char terminal. Not a functional change.

tcp: avoid call to soisconnected() on transition to ESTABLISHED

This call existed since pre-FreeBSD times, and it is hard to understand
why it was there in the first place. After 6f3caa6d815 it def

tcp: avoid call to soisconnected() on transition to ESTABLISHED

This call existed since pre-FreeBSD times, and it is hard to understand
why it was there in the first place. After 6f3caa6d815 it definitely
became necessary always and commit message from f1ee30ccd60 confirms that.
Now that 6f3caa6d815 is effectively backed out by 07285bb4c22, the call
appears to be useful only for sockets that landed on the incomplete queue,
e.g. sockets that have accept_filter(9) enabled on them.

Provide a new TCP flag to mark connections that are known to be on the
incomplete queue, and call soisconnected() only for those connections.

Reviewed by: rrs, tuexen
Differential revision: https://reviews.freebsd.org/D36488

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tcp: Functional implementation of Accurate ECN

The AccECN handshake and TCP header flags are supported,
no support yet for the AccECN option. This minimalistic
implementation is sufficient to suppor

tcp: Functional implementation of Accurate ECN

The AccECN handshake and TCP header flags are supported,
no support yet for the AccECN option. This minimalistic
implementation is sufficient to support DCTCP while
dramatically cutting the number of ACKs, and provide ECN
response from the receiver to the CC modules.

Reviewed By: #transport, #manpages, rrs, pauamma
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D21011

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protosw: refactor protosw and domain static declaration and load

o Assert that every protosw has pr_attach. Now this structure is
only for socket protocols declarations and nothing else.
o Merge

protosw: refactor protosw and domain static declaration and load

o Assert that every protosw has pr_attach. Now this structure is
only for socket protocols declarations and nothing else.
o Merge struct pr_usrreqs into struct protosw. This was suggested
in 1996 by wollman@ (see 7b187005d18ef), and later reiterated
in 2006 by rwatson@ (see 6fbb9cf860dcd).
o Make struct domain hold a variable sized array of protosw pointers.
For most protocols these pointers are initialized statically.
Those domains that may have loadable protocols have spacers. IPv4
and IPv6 have 8 spacers each (andre@ dff3237ee54ea).
o For inetsw and inet6sw leave a comment noting that many protosw
entries very likely are dead code.
o Refactor pf_proto_[un]register() into protosw_[un]register().
o Isolate pr_*_notsupp() methods into uipc_domain.c

Reviewed by: melifaro
Differential revision: https://reviews.freebsd.org/D36232

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protosw: retire pr_drain and use EVENTHANDLER(9) directly

The method was called for two different conditions: 1) the VM layer is
low on pages or 2) one of UMA zones of mbuf allocator exhausted.
This

protosw: retire pr_drain and use EVENTHANDLER(9) directly

The method was called for two different conditions: 1) the VM layer is
low on pages or 2) one of UMA zones of mbuf allocator exhausted.
This change 2) into a new event handler, but all affected network
subsystems modified to subscribe to both, so this change shall not
bring functional changes under different low memory situations.

There were three subsystems still using pr_drain: TCP, SCTP and frag6.
The latter had its protosw entry for the only reason to register its
pr_drain method.

Reviewed by: tuexen, melifaro
Differential revision: https://reviews.freebsd.org/D36164

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tcp: use callout(9) directly instead of pr_slowtimo

Modern TCP stacks uses multiple callouts per tcpcb, and a global
callout is ancient artifact. However it is still used to garbage
collect compres

tcp: use callout(9) directly instead of pr_slowtimo

Modern TCP stacks uses multiple callouts per tcpcb, and a global
callout is ancient artifact. However it is still used to garbage
collect compressed timewait entries.

Reviewed by: melifaro, tuexen
Differential revision: https://reviews.freebsd.org/D36159

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tcp: use a TCP flag to check if connection has been close(2)d

The flag SS_NOFDREF is a private flag of the socket layer. It also
is supposed to be read with SOCK_LOCK(), which we don't own here.

R

tcp: use a TCP flag to check if connection has been close(2)d

The flag SS_NOFDREF is a private flag of the socket layer. It also
is supposed to be read with SOCK_LOCK(), which we don't own here.

Reviewed by: rrs, tuexen
Differential revision: https://reviews.freebsd.org/D35663

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tcp_log_vain/addrs: Use a const pointer for the IPv4 header.

The pointer to the IPv6 header was already const.

tcp: Congestion control move to using reference counting.

In the transport call on 12/3 Gleb asked to move the CC modules towards
using reference counting to prevent folks from unloading a module in

tcp: Congestion control move to using reference counting.

In the transport call on 12/3 Gleb asked to move the CC modules towards
using reference counting to prevent folks from unloading a module in use.
It was also agreed that Michael would do a user space utility like tcp_drop
that could be used to move all connections that are using a specific CC
to some other CC.

This is the half I committed to doing, making it so that we maintain a refcount
on a cc module every time a pcb refers to it and decrementing that every
time a pcb no longer uses a cc module. This also helps us simplify the
whole unloading process by getting rid of tcp_ccunload() which munged
through all the tcb's. Instead we mark a module as being removed and
prevent further references to it. We also make sure that if a module is
marked as being removed it cannot be made as the default and also
the opposite of that, if its a default it fails and does not mark it as being
removed.

Reviewed by: Michael Tuexen, Gleb Smirnoff
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D33249

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tcp: Restore 6 tcps padding entries in HEAD

The padding in CURRENT shall not shrink. It is
designed that in CURRENT at always stays
the same, and then when a new stable is branched, it
inherits 6 po

tcp: Restore 6 tcps padding entries in HEAD

The padding in CURRENT shall not shrink. It is
designed that in CURRENT at always stays
the same, and then when a new stable is branched, it
inherits 6 pointer placeholders that can be used
withing this stable/X lifetime to extend the structure.

Reviewed By: tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D34269

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