tcp cc: re-organize newreno functions into parts that can be re-used

Reviewed by: rscheff, tuexen
Differential Revision: https://reviews.freebsd.org/D46046

tcp cc: clean up some un-used cc_var flags

Reviewed by: tuexen
Differential Revision: https://reviews.freebsd.org/D46299

tcp cc: remove non-working sctp support

As suggested by lstewart, remove the non-working SCTP support in the
TCP congestion control modules. SCTP has a similar functionality
(although not using kern

tcp cc: remove non-working sctp support

As suggested by lstewart, remove the non-working SCTP support in the
TCP congestion control modules. SCTP has a similar functionality
(although not using kernel loadable modules), on which the TCP stuff
was built on, but the integration was never done.
No functional change intended.

Reviewed by: Peter Lei, cc
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D46142

show more ...

tcp: retain some CC signals outside of kernel scope

Summary: fix build error after f74352fbcf15341accaf5a92240871f98323215d

Reviewers: #transport!

Subscribers: imp, melifaro, glebius

Differential

tcp: retain some CC signals outside of kernel scope

Summary: fix build error after f74352fbcf15341accaf5a92240871f98323215d

Reviewers: #transport!

Subscribers: imp, melifaro, glebius

Differential Revision: https://reviews.freebsd.org/D44066

show more ...

tcp: use enum for all congestion control signals

Facilitate easier troubleshooting by enumerating
all congestion control signals. Typecast the
enum to int, when a congestion control module uses
priv

tcp: use enum for all congestion control signals

Facilitate easier troubleshooting by enumerating
all congestion control signals. Typecast the
enum to int, when a congestion control module uses
private signals.

No external change.

Reviewed By: glebius, tuexen, #transport
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D43838

show more ...

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

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

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

show more ...

tcp: Make all references to CUBIC uppercase

Consistently refer to the CUBIC congestion control
mechanism in uppercase throughout all comments.

No functional change.

Reviewed By: #transport, tuexen

tcp: Make all references to CUBIC uppercase

Consistently refer to the CUBIC congestion control
mechanism in uppercase throughout all comments.

No functional change.

Reviewed By: #transport, tuexen, mav, guest-ccui, emaste
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D36547

show more ...

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

show more ...

tcp: Add hystart++ to our cubic implementation.

As promised to the transport call on 11/4/22 here is an implementation
of hystart++ for cubic. It also cleans up the tcp_congestion function
to have a

tcp: Add hystart++ to our cubic implementation.

As promised to the transport call on 11/4/22 here is an implementation
of hystart++ for cubic. It also cleans up the tcp_congestion function
to have a better name. Common variables are moved into the general
cc.h structure so that both cubic and newreno can use them for
hystart++

Reviewed by: Michael Tuexen, Richard Scheffenegger
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D33035

show more ...

tcp: Congestion control cleanup.

NOTE: HEADS UP read the note below if your kernel config is not including GENERIC!!

This patch does a bit of cleanup on TCP congestion control modules. There were s

tcp: Congestion control cleanup.

NOTE: HEADS UP read the note below if your kernel config is not including GENERIC!!

This patch does a bit of cleanup on TCP congestion control modules. There were some rather
interesting surprises that one could get i.e. where you use a socket option to change
from one CC (say cc_cubic) to another CC (say cc_vegas) and you could in theory get
a memory failure and end up on cc_newreno. This is not what one would expect. The
new code fixes this by requiring a cc_data_sz() function so we can malloc with M_WAITOK
and pass in to the init function preallocated memory. The CC init is expected in this
case *not* to fail but if it does and a module does break the
"no fail with memory given" contract we do fall back to the CC that was in place at the time.

This also fixes up a set of common newreno utilities that can be shared amongst other
CC modules instead of the other CC modules reaching into newreno and executing
what they think is a "common and understood" function. Lets put these functions in
cc.c and that way we have a common place that is easily findable by future developers or
bug fixers. This also allows newreno to evolve and grow support for its features i.e. ABE
and HYSTART++ without having to dance through hoops for other CC modules, instead
both newreno and the other modules just call into the common functions if they desire
that behavior or roll there own if that makes more sense.

Note: This commit changes the kernel configuration!! If you are not using GENERIC in
some form you must add a CC module option (one of CC_NEWRENO, CC_VEGAS, CC_CUBIC,
CC_CDG, CC_CHD, CC_DCTCP, CC_HTCP, CC_HD). You can have more than one defined
as well if you desire. Note that if you create a kernel configuration that does not
define a congestion control module and includes INET or INET6 the kernel compile will
break. Also you need to define a default, generic adds 'options CC_DEFAULT=\"newreno\"
but you can specify any string that represents the name of the CC module (same names
that show up in the CC module list under net.inet.tcp.cc). If you fail to add the
options CC_DEFAULT in your kernel configuration the kernel build will also break.

Reviewed by: Michael Tuexen
Sponsored by: Netflix Inc.
RELNOTES:YES
Differential Revision: https://reviews.freebsd.org/D32693

show more ...

tcp: Add hystart-plus to cc_newreno and rack.

TCP Hystart draft version -03:
https://datatracker.ietf.org/doc/html/draft-ietf-tcpm-hystartplusplus

Is a new version of hystart that allows one to car

tcp: Add hystart-plus to cc_newreno and rack.

TCP Hystart draft version -03:
https://datatracker.ietf.org/doc/html/draft-ietf-tcpm-hystartplusplus

Is a new version of hystart that allows one to carefully exit slow start if the RTT
spikes too much. The newer version has a slower-slow-start so to speak that then
kicks in for five round trips. To see if you exited too early, if not into congestion avoidance.
This commit will add that feature to our newreno CC and add the needed bits in rack to
be able to enable it.

Reviewed by: tuexen
Sponsored by: Netflix Inc.
Differential Revision: https://reviews.freebsd.org/D32373

show more ...

This brings into sync FreeBSD with the netflix versions of rack and bbr.
This fixes several breakages (panics) since the tcp_lro code was
committed that have been reported. Quite a few new features a

This brings into sync FreeBSD with the netflix versions of rack and bbr.
This fixes several breakages (panics) since the tcp_lro code was
committed that have been reported. Quite a few new features are
now in rack (prefecting of DGP -- Dynamic Goodput Pacing among the
largest). There is also support for ack-war prevention. Documents
comming soon on rack..

Sponsored by: Netflix
Reviewed by: rscheff, mtuexen
Differential Revision: https://reviews.freebsd.org/D30036

show more ...

cc_mod: remove unused CCF_DELACK definition

During the DCTCP improvements, use of CCF_DELACK was
removed. This change is just to rename the unused flag
bit to prevent use of it, without also re-impl

cc_mod: remove unused CCF_DELACK definition

During the DCTCP improvements, use of CCF_DELACK was
removed. This change is just to rename the unused flag
bit to prevent use of it, without also re-implementing
the tcp_input and tcp_output interfaces.

No functional change.

Reviewed by: chengc_netapp.com, tuexen
MFC after: 2 weeks
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D26181

show more ...

Make use of the stats(3) framework in the TCP stack.

This makes it possible to retrieve per-connection statistical
information such as the receive window size, RTT, or goodput,
using a newly added T

Make use of the stats(3) framework in the TCP stack.

This makes it possible to retrieve per-connection statistical
information such as the receive window size, RTT, or goodput,
using a newly added TCP_STATS getsockopt(3) option, and extract
them using the stats_voistat_fetch(3) API.

See the net/tcprtt port for an example consumer of this API.

Compared to the existing TCP_INFO system, the main differences
are that this mechanism is easy to extend without breaking ABI,
and provides statistical information instead of raw "snapshots"
of values at a given point in time. stats(3) is more generic
and can be used in both userland and the kernel.

Reviewed by: thj
Tested by: thj
Obtained from: Netflix
Relnotes: yes
Sponsored by: Klara Inc, Netflix
Differential Revision: https://reviews.freebsd.org/D20655

show more ...

Revert r331567 CC Cubic: fix underflow for cubic_cwnd()

This change is causing TCP connections using cubic to hang. Need to dig more to
find exact cause and fix it.

Reported by: tj at mrsk dot me,

Revert r331567 CC Cubic: fix underflow for cubic_cwnd()

This change is causing TCP connections using cubic to hang. Need to dig more to
find exact cause and fix it.

Reported by: tj at mrsk dot me, Matt Garber (via twitter)
Discussed with: sbruno (previously), allanjude, cperciva
MFC after: 3 days

show more ...

Merge ^/head r340918 through r341763.

Limit option_len for the TCP_CCALGOOPT.

Limiting the length to 2048 bytes seems to be acceptable, since
the values used right now are using 8 bytes.

Reviewed by: glebius, bz, rrs
MFC after: 3 day

Limit option_len for the TCP_CCALGOOPT.

Limiting the length to 2048 bytes seems to be acceptable, since
the values used right now are using 8 bytes.

Reviewed by: glebius, bz, rrs
MFC after: 3 days
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D18366

show more ...

CC Cubic: fix underflow for cubic_cwnd()

Singed calculations in cubic_cwnd() can result in negative cwnd
value which is then cast to an unsigned value. Values less than
1 mss are generally bad for o

CC Cubic: fix underflow for cubic_cwnd()

Singed calculations in cubic_cwnd() can result in negative cwnd
value which is then cast to an unsigned value. Values less than
1 mss are generally bad for other parts of the code, also fixed.

Submitted by: Jason Eggleston <jason@eggnet.com>
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D14141

show more ...

Add support for the experimental Internet-Draft "TCP Alternative Backoff with
ECN (ABE)" proposal to the New Reno congestion control algorithm module.
ABE reduces the amount of congestion window redu

Add support for the experimental Internet-Draft "TCP Alternative Backoff with
ECN (ABE)" proposal to the New Reno congestion control algorithm module.
ABE reduces the amount of congestion window reduction in response to
ECN-signalled congestion relative to the loss-inferred congestion response.

More details about ABE can be found in the Internet-Draft:
https://tools.ietf.org/html/draft-ietf-tcpm-alternativebackoff-ecn

The implementation introduces four new sysctls:

- net.inet.tcp.cc.abe defaults to 0 (disabled) and can be set to non-zero to
enable ABE for ECN-enabled TCP connections.

- net.inet.tcp.cc.newreno.beta and net.inet.tcp.cc.newreno.beta_ecn set the
multiplicative window decrease factor, specified as a percentage, applied to
the congestion window in response to a loss-based or ECN-based congestion
signal respectively. They default to the values specified in the draft i.e.
beta=50 and beta_ecn=80.

- net.inet.tcp.cc.abe_frlossreduce defaults to 0 (disabled) and can be set to
non-zero to enable the use of standard beta (50% by default) when repairing
loss during an ECN-signalled congestion recovery episode. It enables a more
conservative congestion response and is provided for the purposes of
experimentation as a result of some discussion at IETF 100 in Singapore.

The values of beta and beta_ecn can also be set per-connection by way of the
TCP_CCALGOOPT TCP-level socket option and the new CC_NEWRENO_BETA or
CC_NEWRENO_BETA_ECN CC algo sub-options.

Submitted by: Tom Jones <tj@enoti.me>
Tested by: Tom Jones <tj@enoti.me>, Grenville Armitage <garmitage@swin.edu.au>
Relnotes: Yes
Differential Revision: https://reviews.freebsd.org/D11616

show more ...

Merge ^/head r312207 through r312308.

MFhead@r312305

Fix a variety of cosmetic typos and misspellings

No functional change.

PR: 216096, 216097, 216098, 216101, 216102, 216106, 216109, 216110
Reported by: Bulat <bltsrc at mail.ru>
Sponsored by: Dell

Fix a variety of cosmetic typos and misspellings

No functional change.

PR: 216096, 216097, 216098, 216101, 216102, 216106, 216109, 216110
Reported by: Bulat <bltsrc at mail.ru>
Sponsored by: Dell EMC Isilon

show more ...

Merge ^/head r304700 through r304884.

MFhead @ r304815