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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
