20 Commits

Author SHA1 Message Date
Victor Boivie
3c6b46fc16 Reland "dcsctp: Support zero checksum packets"
This reverts commit 45eae346930aedbf4624d054e0633c94b397b8ec.

It was found not to be the root cause of the performance
regression, so it's safe to reland.

Bug: webrtc:14997
Change-Id: I67c90752875bf4071cbdd5adfa462a37f4d4ceab
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/302162
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#39910}
2023-04-20 20:32:01 +00:00
Victor Boivie
45eae34693 Revert "dcsctp: Support zero checksum packets"
This reverts commit bd46bb7660fbc9f31799196058f7a1957f50aa31.

Reason for revert: There is a slight performance degradation
pointing to this CL, so revert this to be able to confirm if
it is the culprit.


Original change's description:
> dcsctp: Support zero checksum packets
>
> If configured, the packet parser will allow packets with
> a set checksum of zero. In that case, the correct checksum
> will not even be calculated, avoiding a CPU intensive
> calculation.
>
> Also, if specified when building a packet, the checksum can
> be opted to be not calculated and written to the packet.
> This is to be used when draft-tuexen-tsvwg-sctp-zero-checksum
> has been negotiated, except for some packets during association
> establishment.
>
> This is mainly a preparation CL and follow-up CL will enable
> this feature.
>
> Low-Coverage-Reason: Affects debug logging code not run in tests
> Bug: webrtc:14997
> Change-Id: I3207ac3a626df039ee2990403c2edd6429f17617
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/298481
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Commit-Queue: Victor Boivie <boivie@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#39737}

Bug: webrtc:14997
Change-Id: Ie22267abb4bcd25d5af07875eb933c51ed5be853
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/301580
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39878}
2023-04-17 19:29:55 +00:00
Victor Boivie
bd46bb7660 dcsctp: Support zero checksum packets
If configured, the packet parser will allow packets with
a set checksum of zero. In that case, the correct checksum
will not even be calculated, avoiding a CPU intensive
calculation.

Also, if specified when building a packet, the checksum can
be opted to be not calculated and written to the packet.
This is to be used when draft-tuexen-tsvwg-sctp-zero-checksum
has been negotiated, except for some packets during association
establishment.

This is mainly a preparation CL and follow-up CL will enable
this feature.

Low-Coverage-Reason: Affects debug logging code not run in tests
Bug: webrtc:14997
Change-Id: I3207ac3a626df039ee2990403c2edd6429f17617
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/298481
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39737}
2023-04-02 21:38:00 +00:00
Victor Boivie
7e897aeb92 dcsctp: Add public API for setting priorities
This is a reland of commit 17a02a31d7d2897b75ad69fdac5d10e7475a5865.

This is the first part of supporting stream priorities, and adds the API
and very basic support for setting and retrieving the stream priority.

This commit doesn't in any way change the actual packet sending - the
specified priority values are stored, but not acted on.

This is all that is client visible, so clients can start using the API
as written, and they would never notice that things are missing.

Bug: webrtc:5696
Change-Id: I04d64a63cbaec67568496ad99667e14eba85f2e0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264424
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37081}
2022-06-01 20:46:25 +00:00
Björn Terelius
51e5bacb8b Revert "dcsctp: Add public API for setting priorities"
This reverts commit 17a02a31d7d2897b75ad69fdac5d10e7475a5865.

Reason for revert: Breaks downstream test

Original change's description:
> dcsctp: Add public API for setting priorities
>
> This is the first part of supporting stream priorities, and adds the API
> and very basic support for setting and retrieving the stream priority.
>
> This commit doesn't in any way change the actual packet sending - the
> specified priority values are stored, but not acted on.
>
> This is all that is client visible, so clients can start using the API
> as written, and they would never notice that things are missing.
>
> Bug: webrtc:5696
> Change-Id: I24fce8cbb6f3cba187df99d1d3f45e73621c93c6
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/261943
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Commit-Queue: Victor Boivie <boivie@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#37034}

Bug: webrtc:5696
Change-Id: If172d9c9dbce7aae72152abbbae1ccc77340bbc1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264444
Owners-Override: Björn Terelius <terelius@webrtc.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Auto-Submit: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37039}
2022-05-30 14:12:34 +00:00
Victor Boivie
17a02a31d7 dcsctp: Add public API for setting priorities
This is the first part of supporting stream priorities, and adds the API
and very basic support for setting and retrieving the stream priority.

This commit doesn't in any way change the actual packet sending - the
specified priority values are stored, but not acted on.

This is all that is client visible, so clients can start using the API
as written, and they would never notice that things are missing.

Bug: webrtc:5696
Change-Id: I24fce8cbb6f3cba187df99d1d3f45e73621c93c6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/261943
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37034}
2022-05-30 10:05:03 +00:00
Victor Boivie
adfe54c965 dcsctp: Remove the TCP style cwnd doubling
It wasn't correct and not enabled by default, so just remove it.

Bug: webrtc:12943
Change-Id: Idd426abd0da4ae259e519dd01239b4303296756a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/232609
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35075}
2021-09-23 08:06:46 +00:00
Victor Boivie
d68f18ee6e dcsctp: Allow specifying minimum RTT variance
This is mentioned in
https://datatracker.ietf.org/doc/html/rfc4960#section-6.3.1 and further
described in https://datatracker.ietf.org/doc/html/rfc6298#section-4.

The TCP RFCs mentioned G as the clock granularity, but in SCTP it should
be set much higher, to account for the delayed ack timeout (ATO) of the
peer (as that can be seen as a very high clock granularity). That one is
set to 200ms by default in many clients, so a reasonable default limit
could be set to 220 ms.

If the measured variance is higher, it will be used instead.

Bug: webrtc:12943
Change-Id: Ifc217daa390850520da8b3beb0ef214181ff8c4e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/232614
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35068}
2021-09-22 20:22:54 +00:00
Victor Boivie
2e78f09c1a dcsctp: Increase RTO limits
The previous limits were taken from Oracles SCTP stack[1] as they were
more up-to-date than the suggested ones in RFC4960. However, after
having evaluated them for a while, it's evident that they are a bit too
aggressive and likely have their origin from a wired LAN network.

Let's do a re-take. These values have been taken from Solaris TCP
stack[2]. They are even less aggressive than Linux defaults. This can be
iterated even more, and is always possible to override by the client.

It's generally the increase of rto_min that is helping here, as the
delayed SACK and RTT jitter require that the RTO.min is quite much
higher than the delayed SACK timeout of the peer (which isn't in control
by us, but one can assume it's 200ms or less). And with a too low
RTO.min, it's increased risk of getting spurious retransmissions and
decreasing the congestion window.

[1] https://docs.oracle.com/cd/E93309_01/docs.466/SIGTRAN/GUID-2136614F-4BED-407C-87B0-7EE10E0FF534.htm
[2] https://docs.oracle.com/cd/E19120-01/open.solaris/819-2724/chapter4-69/index.html

Bug: webrtc:12943
Change-Id: I9678ac4396286a55c251c5f57589379da70fd27d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231139
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34927}
2021-09-06 10:24:06 +00:00
Victor Boivie
cebbff7f58 dcsctp: Specify the max timer backoff duration
By allowing the max timer backoff duration to be limited, a socket can
fast recover in case of intermittent network issues. Before this CL, the
exponential backoff algorithm could result in very long retry durations
(in the order of minutes), when connection has been lost or been flaky
for a long while.

Note that limiting the maximum backoff duration might require
compensating the maximum retransmission limit to avoid closing the
socket prematurely due to reaching the maximum retransmission limit much
faster than previously.

Bug: webrtc:13129
Change-Id: Ib94030d666433e3fa1a2c8ef69750a1afab8ef94
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/230702
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34913}
2021-09-03 10:26:50 +00:00
Victor Boivie
9680d29e8d dcsctp: Support unlimited max_retransmissions
The restart limit for timers can already be limitless, but the
RetransmissionErrorCounter didn't support this. With this change, the
max_retransmissions and max_init_retransmits can be absl::nullopt to
indicate that there should be infinite retries.

Bug: webrtc:13129
Change-Id: Ia6e91cccbc2e1bb77b3fdd7f37436290adc2f483
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/230701
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34882}
2021-08-31 10:57:48 +00:00
Victor Boivie
14ef6338b0 dcsctp: Don't send small packets when cwnd full
The congestion window is unlikely to be even divisible by the size
of a packet, so when the congestion window is almost full, there is
often just a few bytes remaining in it. Before this change, a small
packet was created to fill the remaining bytes in the congestion window,
to make it really full.

Small packets don't add much. The cost of sending a small packet is
often the same as sending a large one, and you usually get lower
throughput sending many small packets compared to few larger ones.'

This mode will only be enabled when the congestion window is large, so
if the congestion window is small - e.g. due to poor network conditions,
it will allow packets to become fragmented into small parts, in order to
fully utilize the congestion window.

Bug: webrtc:12943
Change-Id: I8522459174bc72df569edd57f5cc4a494a4b93a8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/228526
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34778}
2021-08-17 09:03:36 +00:00
Victor Boivie
e0fb45c6d4 dcsctp: Add burst limiter for sent packets
Some deployments, e.g. Chromium, has a limited send buffer. It's
reasonable that it's quite small, as it avoids queuing too much, which
typically results in increased latency for real-time communication. To
avoid SCTP to fill up the entire buffer at once - especially when doing
fast retransmissions - limit the amount of packets that are sent in one
go.

In a typical scenario, SCTP will not send more than three packets for
each incoming packet, which is is the case when a SACK is received which
has acknowledged two large packets, and which also adds the MTU to the
congestion window (due to in slow-start mode), which then may result in
sending three packets. So setting this value to four makes any
retransmission not use that much more of the send buffer.

This is analogous to usrsctp_sysctl_set_sctp_fr_max_burst_default in
usrsctp, which also has the default value of four (4).

Bug: webrtc:12943
Change-Id: Iff76a1668beadc8776fab10312ef9ee26f24e442
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/228480
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34744}
2021-08-12 17:22:55 +00:00
Victor Boivie
5429d71022 dcsctp: Allow heartbeats to be disabled
This is useful in tests and in scenarios where the connection is
monitored externally and the heartbeat monitoring would be of no use.

Bug: webrtc:12614
Change-Id: Ida4f4e2e40fc4d2aa0c27ae9431f434da4cc8313
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/220766
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34164}
2021-05-31 12:19:38 +00:00
Victor Boivie
236ac50628 dcsctp: Add public API for BufferedAmountLow
This adds native support for the RTCDataChannel properties:
https://developer.mozilla.org/en-US/docs/Web/API/RTCDataChannel/bufferedAmount
https://developer.mozilla.org/en-US/docs/Web/API/RTCDataChannel/bufferedAmountLowThreshold

And the RTCDataChannel event:
https://developer.mozilla.org/en-US/docs/Web/API/RTCDataChannel/onbufferedamountlow

The old callback, NotifyOutgoingMessageBufferEmpty, is deprecated as it
didn't work very well. It will not be triggered and will be removed
as soon as all users of it are gone. There is a new callback,
OnTotalBufferedAmountLow, that serves the same purpose but also allows
setting an arbitrary limit when it should be triggered (See
DcSctpOptions::total_buffered_amount_low_threshold).

Bug: webrtc:12794
Change-Id: Ic1c92f174eff8a1acda0b5fd3dcc45bd1cfa2704
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219691
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34144}
2021-05-27 15:27:27 +00:00
Victor Boivie
cfa932f6fc dcsctp: Bump rto_min to 220 ms
The minimum RTO time shouldn't be lower than the delayed ack timeout
of the peer to avoid sending retransmissions before the peer has
actually intended to reply.

In usrsctp, the default delayed ack timeout is 200ms and configurable
using the `sctp_delayed_sack_time_default` option. In dcsctp, it's
min(RTO/2, 200ms), to avoid this issue.

Bug: webrtc:12614
Change-Id: Ie84c331334af660d66b1a7d90d20f5cf7e2a5103
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219100
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34026}
2021-05-17 17:41:21 +00:00
Victor Boivie
d24729693d dcsctp: Disable TCP style slow start
Due to a limit socket send buffer, it's quite easy to fill it up when
using exponential slow start, which results in dropping a lot of packets
and having to retransmit those.

Disabling this, to align it to how SCTP normally behaves, and then try
to stabilize it later. With SCTP slow start, it will increase with one
MTU for each RTT when there is no packet loss. Even this mode will
experience packet loss, but not as much will be lost, and it will
stabilize quicker.

Bug: webrtc:12614
Change-Id: Ibc484b19b7e708fe5bd837bbef178a2f69b7211f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/218203
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33969}
2021-05-10 20:41:12 +00:00
Victor Boivie
b6580ccb29 dcsctp: Add Socket
This completes the basic implementation of the dcSCTP library. There
are a few remaining commits to e.g. add compatibility tests and
benchmarks, as well as more support for e.g. RFC8260, but those are not
strictly vital for evaluation of the library.

The Socket contains the connection establishment and teardown sequences
as well as the general chunk dispatcher.

Bug: webrtc:12614
Change-Id: I313b6c8f4accc144e3bb88ddba22269ebb8eb3cd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/214342
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33890}
2021-05-01 07:16:21 +00:00
Victor Boivie
27e50ccf4c dcsctp: Add Retransmission Timeout
The socket can measure the round-trip-time (RTT) by two different
scenarios:
  * When a sent data is ACKed
  * When a HEARTBEAT has been sent, which as been ACKed.

The RTT will be used to calculate which timeout value that should be
used for e.g. the retransmission timer (T3-RTX). On connections with a
low RTT, the RTO value will be low, and on a connection with high RTT,
the RTO value will be high. And on a connection with a generally low
RTT value, but where it varies a lot, the RTO value will be calculated
to be fairly high, to not fire unnecessarily. So jitter is bad, and is
part of the calculation.

Bug: webrtc:12614
Change-Id: I64905ad566d5032d0428cd84143a9397355bbe9f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/214045
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33832}
2021-04-26 13:48:41 +00:00
Victor Boivie
628d91cd0d dcsctp: Add public API
Clients will use this API for all their interactions with this library.
It's made into an interface (of which there will only be a single
implementation) simply for documentation purposes. But that also allows
clients to mock the library if wanted or to have a thread-safe wrapper,
as the library itself is not thread-safe, while keeping the same
interface.

Bug: webrtc:12614
Change-Id: I346af9916e26487da040c01825c2547aa7a5d0b7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/213348
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33648}
2021-04-08 08:53:44 +00:00