tree 27a4dbd6c8a9276f62e0fc20bec51f1b8dbb8807
parent 637f8f2ca710c0f11d52fc91f00285fe6eee0e08
author Christopher Faulet <cfaulet@haproxy.com> 1490694693 +0200
committer Willy Tarreau <w@1wt.eu> 1490963780 +0200
encoding latin1

BUG/MINOR: http: Fix conditions to clean up a txn and to handle the next request

To finish a HTTP transaction and to start the new one, we check, among other
things, that there is enough space in the reponse buffer to eventually inject a
message during the parsing of the next request. Because these messages can reach
the maximum buffers size, it is mandatory to have an empty response
buffer. Remaining input data are trimmed during the txn cleanup (in
http_reset_txn), so we just need to check that the output data were flushed.

The current implementation depends on channel_congested, which does check the
reserved area is available. That's not of course good enough. There are other
tests on the reponse buffer is http_wait_for_request. But conditions to move on
are almost the same. So, we can imagine some scenarii where some output data
remaining in the reponse buffer during the request parsing prevent any messages
injection.

To fix this bug, we just wait that output data were flushed before cleaning up
the HTTP txn (ie. s->res.buf->o == 0). In addition, in http_reset_txn we realign
the response buffer (note the buffer is empty at this step).

Thanks to this changes, there is no more need to set CF_EXPECT_MORE on the
response channel in http_end_txn_clean_session. And more important, there is no
more need to check the response buffer state in http_wait_for_request. This
remove a workaround on response analysers to handle HTTP pipelining.

This patch can be backported in 1.7, 1.6 and 1.5.