First there is a typo in the directive name, then it is not documented and
finally, it is not used at all. The directive is only removed from the
keyword list. Parsing function is not updated.
This patch should fix the issue #2601.
The following commits broke the build on FreeBSD when QUIC is enabled:
35470d518 ("MINOR: quic: activate UDP GSO for QUIC if supported")
448d3d388 ("MINOR: quic: add GSO parameter on quic_sock send API")
Indeed, it turns out that netinet/udp.h requires sys/types.h to be
included before. Let's just change the includes order to fix the build.
No backport is needed.
Tests performed between a 1 Gbps connected server and a 100 mbps client,
distant by 95ms showed that:
- we need 1.1 MB in flight to fill the link
- rare but inevitable losses are sufficient to make cubic's window
collapse fast and long to recover
- a 100 MB object takes 69s to download
- tolerance for 1 loss between two ACKs suffices to shrink the download
time to 20-22s
- 2 losses go to 17-20s
- 4 losses reach 14-17s
At 100 concurrent connections that fill the server's link:
- 0 loss tolerance shows 2-3% losses
- 1 loss tolerance shows 3-5% losses
- 2 loss tolerance shows 10-13% losses
- 4 loss tolerance shows 23-29% losses
As such while there can be a significant gain sometimes in setting this
tolerance above zero, it can also significantly waste bandwidth by sending
far more than can be received. While it's probably not a solution to real
world problems, it repeatedly proved to be a very effective troubleshooting
tool helping to figure different root causes of low transfer speeds. In
spirit it is comparable to the no-cc congestion algorithm, i.e. it must
not be used except for experimentation.
QUIC MUX buffer allocation limit is now directly based on the underlying
congestion window size. previous static limit based on conn-tx-buffers
is now unused. As such, this commit adds a warning to users to prevent
that it is now obsolete.
Secondly, update max-window-size setting. It is now the main entrypoint
to limit both the maximum congestion window size and the number of QUIC
MUX allocated buffer on emission. Remove its special value '0' which was
used to automatically adjust it on now unused conn-tx-buffers.
Define a new global keyword tune.quic.frontend.max-window-size. This
allows to set globally the maximum congestion window size for each QUIC
frontend connections.
The default value is 0. It is a special value which automatically derive
the size from the configured QUIC connection buffer limit. This is
similar to the previous "quic-cc-algo" behavior, which can be used to
override the maximum window size per bind line.
quic-cc-algo is a bind line keyword which allow to select a QUIC
congestion algorithm. It can take an optional integer to specify the
maximum window size. This value is an integer and support the suffixes
'k', 'm' and 'g' to specify respectively kilobytes, megabytes and
gigabytes.
Extract the maximum window size parsing in a dedicated function named
parse_window_size(). It accepts as input an integer value with an
optional suffix, 'k', 'm' or 'g'. The first invalid character is
returned by the function to the caller.
No functional change. This commit will allow to quickly implement a new
keyword to configure a default congestion window size in the global
section.
Since commit 35470d518 ("MINOR: quic: activate UDP GSO for QUIC if
supported"), Solaris build fails due to netinet/udp.h being included
without netinet/in.h. Adding it is sufficient to fix the problem. No
backport is needed.
Add ACL condition support for quic-initial rules. This requires the
extension of quic_parse_quic_initial() to parse an extra if/unless
block.
Only layer4 client samples are allowed to be used with quic-initial
rules. However, due to the early execution of quic-initial rules prior
to any connection instantiation, some samples are non supported.
To be able to use the 4 described samples, a dummy session is
instantiated before quic-initial rules execution. Its src and dst fields
are set from the received datagram values.
Implement a new set of rules labelled as quic-initial.
These rules as specific to QUIC. They are scheduled to be executed early
on Initial packet parsing, prior a new QUIC connection instantiation.
Contrary to tcp-request connection, this allows to reject traffic
earlier, most notably by avoiding unnecessary QUIC SSL handshake
processing.
A new module quic_rules is created. Its main function
quic_init_exec_rules() is called on Initial packet parsing in function
quic_rx_pkt_retrieve_conn().
For the moment, only "accept" and "dgram-drop" are valid actions. Both
are final. The latter drops silently the Initial packet instead of
allocating a new QUIC connection.
Add a startup test for GSO support in quic_test_socketopts() and
automatically activate it in qc_prep_pkts() when building datagrams as
big as MTU.
Also define a new config option tune.quic.disable-udp-gso. This is
useful to prevent warning on older platform or to debug an issue which
may be related to GSO.
Implement basic support for glitches on QUIC multiplexer. This is mostly
identical too glitches for HTTP/2.
A new configuration option named tune.quic.frontend.glitches-threshold
is defined to limit the number of glitches on a connection before
closing it.
Glitches counter is incremented via qcc_report_glitch(). A new
qcc_app_ops callback <report_susp> is defined. On threshold reaching, it
allows to set an application error code to close the connection. For
HTTP/3, value H3_EXCESSIVE_LOAD is returned. If not defined, default
code INTERNAL_ERROR is used.
For the moment, no glitch are reported for QUIC or HTTP/3 usage. This
will be added in future patches as needed.
This is a simple algorithm to replace the classic slow start phase of the
congestion control algorithms. It should reduce the high packet loss during
this step.
Implemented only for Cubic.
Let's say that the largest packet number acknowledged by the peer is #10, when inspecting
the non already acknowledged packets to detect if they are lost or not, this is the
case a least if the difference between this largest packet number and and their
packet numbers are bigger or equal to the packet reordering threshold as defined
by the RFC 9002. This latter must not be less than QUIC_LOSS_PACKET_THRESHOLD(3).
Which such a value, packets #7 and oldest are detected as lost if non acknowledged,
contrary to packet number #8 or #9.
So, the packet loss detection is very sensitive to such a network characteristic
where non acknowledged packets are distant from each others by their packet number
differences.
Do not use this static value anymore for the packet reordering threshold which is used
as a criteria to detect packet loss. In place, make it depend on the difference
between the number of the last transmitted packet and the number of the oldest
one among the packet which are still in flight before being inspected to be
deemed as lost.
Add new tune.quic.reorder-ratio setting to apply a ratio in percent to this
dynamic packet reorder threshold.
Should be backported to 2.6.
There is a typo in the statement to initialize this variable when selecting
newreno as cc algo:
const char *newreno = "newrno";
This would have happened if #defines had be used in place of several const char *
variables harcoded values.
Take the opportunity of this patch to use #defines for all the available cc algorithms.
Must be backported to 2.9.
tune.quic.zero-copy-fwd-send can now be used to enable or disable the
zero-copy fast-forwarding for the QUIC mux only, for sends. For now, there
is no option to disable it for receives because it is not supported yet.
It is enabled ('on') by default.
This bug arrived with this commit:
MINOR: quic: Add a max window parameter to congestion control algorithms
The documentation was been modified with missing/wrong modifications in the code part.
The 'g' suffix must be accepted to parse value in gigabytes. And exctly 4g is
also accepted.
No need to backport.
Add a new ->max_cwnd member to bind_conf struct to store the maximum
congestion control window value for each QUIC binding.
Modify the "quic-cc-algo" keyword parsing to add an optional parameter
to its value: the maximum congestion window value between parentheses
as follows:
ex: quic-cc-algo cubic(10m)
This value must be bounded, greater than 10k and smaller than 1g.
Define a new bind option quic-socket :
quic-socket [ connection | listener ]
This new setting works in conjunction with the existing configuration
global tune.quic.socket-owner and reuse the same semantics.
The purpose of this setting is to allow to disable connection socket
usage on listener instances individually. This will notably be useful
when needing to deactivating it when encountered a fatal permission
error on bind() at runtime.
This algorithm does nothing except initializing the congestion control window
to a fixed value. Very smart!
Modify the QUIC congestion control configuration parser to support this new
algorithm. The congestion control algorithm must be set as follows:
quic-cc-algo nocc-<cc window size(KB))
For instance if "nocc-15" is provided as quic-cc-algo keyword value, this
will set a fixed window of 15KB.
Define a new configuration option "tune.quic.max-frame-loss". This is
used to specify the limit for which a single frame instance can be
detected as lost. If exceeded, the connection is closed.
This should be backported up to 2.7.
Define global configuration option "tune.quic.socket-owner". This option
can be used to activate or not socket per QUIC connection mode. The
default value is "listener" which disable this feature. It can be
activated with the option "connection".
This change is part of quic-conn owned socket implementation.
It may be backported to 2.7 after a period of observation.
cfgparse-quic accesses some members of the "global" struct but only
includes global-t.h. It actually used to work via tools.h due to a
long dependency chain that brought it, but it will be fixed and will
break cfgparse-quic, so let's fix it first.
As it could be interesting to be able to choose the QUIC control congestion
algorithm to be used by listener, add "quic-cc-algo" new keyword to do so.
Update the documentation consequently.
Must be backported to 2.6.
Rename "tune.quic.conn-buf-limit" to "tune.quic.frontend.conn-tx-buffers.limit"
to reflect the stream direction (TX) and the objects (frontends) which are
concerned.
Add tunable "tune.quic.frontend.max_streams_bidi" setting for QUIC frontends
to set the "initial_max_streams_bidi" transport parameter.
Add some documentation for this new setting.
Add two tunable settings both for backends and frontends "max_idle_timeout"
QUIC transport parameter, "tune.quic.frontend.max-idle-timeout" and
"tune.quic.backend.max-idle-timeout" respectively.
cfg_parse_quic_time() has been implemented to parse a time value thanks
to parse_time_err(). It should be reused for any tunable time value to be
parsed.
Add the documentation for this tunable setting only for frontend.
This QUIC specific keyword may be used to set the theshold, in number of
connection openings, beyond which QUIC Retry feature will be automatically
enabled. Its default value is 100.
Implement the emission of Retry packets. These packets are emitted in
response to Initial from clients without token. The token from the Retry
packet contains the ODCID from the Initial packet.
By default, Retry packet emission is disabled and the handshake can
continue without address validation. To enable Retry, a new bind option
has been defined named "quic-force-retry". If set, the handshake must be
conducted only after receiving a token in the Initial packet.
