tree d0332e3f077d99868f64e4e0abeed99e7fc9a737
parent c59160ccc76cbafbae5950eff7a8e3ccf1c2bfd4
author Amaury Denoyelle <adenoyelle@haproxy.com> 1704796928 +0100
committer Christopher Faulet <cfaulet@haproxy.com> 1705496441 +0100

BUG/MINOR: mux-quic: do not prevent non-STREAM sending on flow control

Data emitted by QUIC MUX is restrained by the peer flow control. This is
checked on stream and connection level inside qcc_io_send().

The connection level check was placed early in qcc_io_send() preambule.
However, this also prevents emission of other frames STOP_SENDING and
RESET_STREAM, until flow control limitation is increased by a received
MAX_DATA. Note that local flow control frame emission is done prior in
qcc_io_send() and so are not impacted.

In the worst case, if no MAX_DATA is received for some time, this could
delay significantly streams closure and resource free. However, this
should be rare as other peers should anticipate emission of MAX_DATA
before reaching flow control limit. In the end, this is also covered by
the MUX timeout so the impact should be minimal

To fix this, move the connection level check directly inside QCS sending
loop. Note that this could cause unnecessary looping when connection
flow control level is reached and no STOP_SENDING/RESET_STREAM are
needed.

This should be backported up to 2.6.

(cherry picked from commit 333f2cababa36f4289493647fed4f7dce0babc77)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 696337f631a57ffb8420df7ed8867e8af0e577fc)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>