tree df3ea5d963662b3d031f9782731d7a13182d464a
parent a7e8485838e30f921b9d34045f0ebf8672bb0259
author Christopher Faulet <cfaulet@haproxy.com> 1635511027 +0200
committer Willy Tarreau <w@1wt.eu> 1635927445 +0100
encoding latin1

BUG/MEDIUM: http-ana: Drain request data waiting the tarpit timeout expiration

When a tarpit action is performed, we must be sure to drain data from the
request channel. Otherwise, the mux on the frontend side may be blocked
because the request channel buffer is full.

This may lead to Two bugs. The first one is a HOL blocking on the H2
multiplexer. A tarpitted stream may block all the others because data are
not drained for the whole tarpit timeout. The second bug is a ping-pong loop
between the multiplexer and the stream. The mux is waiting for more space in
the channel buffer, so it wakes up the stream. And the stream systematically
re-enables receives.

This last part is not pretty clean and it will be addressed with another
fix. But draning request data is a good way to fix both bugs in same time.

This patch must be backported as far as 2.0. The legacy HTTP mode is
probably affected, but I don't know if same bugs may be experienced in this
mode.

(cherry picked from commit b0c87f1c61edbc4e4affd81d2fd02e113528cf03)
Signed-off-by: Willy Tarreau <w@1wt.eu>