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Willy Tarreau c192b0ab95 MEDIUM: connection: remove CO_FL_CONNECTED and only rely on CO_FL_WAIT_*
Commit 477902bd2e ("MEDIUM: connections: Get ride of the xprt_done
callback.") broke the master CLI for a very obscure reason. It happens
that short requests immediately terminated by a shutdown are properly
received, CS_FL_EOS is correctly set, but in si_cs_recv(), we refrain
from setting CF_SHUTR on the channel because CO_FL_CONNECTED was not
yet set on the connection since we've not passed again through
conn_fd_handler() and it was not done in conn_complete_session(). While
commit a8a415d31a ("BUG/MEDIUM: connections: Set CO_FL_CONNECTED in
conn_complete_session()") fixed the issue, such accident may happen
again as the root cause is deeper and actually comes down to the fact
that CO_FL_CONNECTED is lazily set at various check points in the code
but not every time we drop one wait bit. It is not the first time we
face this situation.

Originally this flag was used to detect the transition between WAIT_*
and CONNECTED in order to call ->wake() from the FD handler. But since
at least 1.8-dev1 with commit 7bf3fa3c23 ("BUG/MAJOR: connection: update
CO_FL_CONNECTED before calling the data layer"), CO_FL_CONNECTED is
always synchronized against the two others before being checked. Moreover,
with the I/Os moved to tasklets, the decision to call the ->wake() function
is performed after the I/Os in si_cs_process() and equivalent, which don't
care about this transition either.

So in essence, checking for CO_FL_CONNECTED has become a lazy wait to
check for (CO_FL_WAIT_L4_CONN | CO_FL_WAIT_L6_CONN), but that always
relies on someone else having synchronized it.

This patch addresses it once for all by killing this flag and only checking
the two others (for which a composite mask CO_FL_WAIT_L4L6 was added). This
revealed a number of inconsistencies that were purposely not addressed here
for the sake of bisectability:

  - while most places do check both L4+L6 and HANDSHAKE at the same time,
    some places like assign_server() or back_handle_st_con() and a few
    sample fetches looking for proxy protocol do check for L4+L6 but
    don't care about HANDSHAKE ; these ones will probably fail on TCP
    request session rules if the handshake is not complete.

  - some handshake handlers do validate that a connection is established
    at L4 but didn't clear CO_FL_WAIT_L4_CONN

  - the ->ctl method of mux_fcgi, mux_pt and mux_h1 only checks for L4+L6
    before declaring the mux ready while the snd_buf function also checks
    for the handshake's completion. Likely the former should validate the
    handshake as well and we should get rid of these extra tests in snd_buf.

  - raw_sock_from_buf() would directly set CO_FL_CONNECTED and would only
    later clear CO_FL_WAIT_L4_CONN.

  - xprt_handshake would set CO_FL_CONNECTED itself without actually
    clearing CO_FL_WAIT_L4_CONN, which could apparently happen only if
    waiting for a pure Rx handshake.

  - most places in ssl_sock that were checking CO_FL_CONNECTED don't need
    to include the L4 check as an L6 check is enough to decide whether to
    wait for more info or not.

It also becomes obvious when reading the test in si_cs_recv() that caused
the failure mentioned above that once converted it doesn't make any sense
anymore: having CS_FL_EOS set while still waiting for L4 and L6 to complete
cannot happen since for CS_FL_EOS to be set, the other ones must have been
validated.

Some of these parts will still deserve further cleanup, and some of the
observations above may induce some backports of potential bug fixes once
totally analyzed in their context. The risk of breaking existing stuff
is too high to blindly backport everything.
2020-01-23 14:41:37 +01:00
.github BUILD: CI: move cygwin builds to Github Actions 2020-01-22 22:51:30 +01:00
contrib MEDIUM: connection: remove CO_FL_CONNECTED and only rely on CO_FL_WAIT_* 2020-01-23 14:41:37 +01:00
doc MEDIUM: cli: Allow multiple filter entries for "show table" 2020-01-22 14:33:17 +01:00
ebtree BUILD: ebtree: make eb_is_empty() and eb_is_dup() take a const 2019-10-02 15:24:19 +02:00
examples CLEANUP: removed obsolete examples an move a few to better places 2019-06-15 21:25:06 +02:00
include MEDIUM: connection: remove CO_FL_CONNECTED and only rely on CO_FL_WAIT_* 2020-01-23 14:41:37 +01:00
reg-tests REGEST: Add reg tests about error files 2020-01-20 15:19:55 +01:00
scripts REGTEST: run-regtests: implement #REQUIRE_BINARIES 2019-12-19 14:36:46 +01:00
src MEDIUM: connection: remove CO_FL_CONNECTED and only rely on CO_FL_WAIT_* 2020-01-23 14:41:37 +01:00
tests TESTS: Add a stress-test for mt_lists. 2019-09-23 18:16:08 +02:00
.cirrus.yml BUILD: cirrus-ci: choose proper openssl package name 2020-01-08 16:26:11 +01:00
.gitignore DOC: create a BRANCHES file to explain the life cycle 2019-06-15 22:00:14 +02:00
.travis.yml BUILD: CI: move cygwin builds to Github Actions 2020-01-22 22:51:30 +01:00
BRANCHES DOC: create a BRANCHES file to explain the life cycle 2019-06-15 22:00:14 +02:00
CHANGELOG CLEANUP: changelog: remove the duplicate entry for 2.2-dev1 2020-01-22 18:57:32 +01:00
CONTRIBUTING DOC: improve the wording in CONTRIBUTING about how to document a bug fix 2019-07-26 15:46:21 +02:00
INSTALL DOC: this is development again 2019-11-25 20:37:49 +01:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS DOC: wurfl: added point of contact in MAINTAINERS file 2019-04-23 11:00:23 +02:00
Makefile BUILD: reorder the objects in the makefile 2019-11-25 19:47:23 +01:00
README DOC: create a BRANCHES file to explain the life cycle 2019-06-15 22:00:14 +02:00
ROADMAP DOC: update the outdated ROADMAP file 2019-06-15 21:59:54 +02:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 2.2-dev1 2020-01-22 10:34:58 +01:00
VERSION [RELEASE] Released version 2.2-dev1 2020-01-22 10:34:58 +01:00

The HAProxy documentation has been split into a number of different files for
ease of use.

Please refer to the following files depending on what you're looking for :

  - INSTALL for instructions on how to build and install HAProxy
  - BRANCHES to understand the project's life cycle and what version to use
  - LICENSE for the project's license
  - CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory :

  - doc/intro.txt for a quick introduction on HAProxy
  - doc/configuration.txt for the configuration's reference manual
  - doc/lua.txt for the Lua's reference manual
  - doc/SPOE.txt for how to use the SPOE engine
  - doc/network-namespaces.txt for how to use network namespaces under Linux
  - doc/management.txt for the management guide
  - doc/regression-testing.txt for how to use the regression testing suite
  - doc/peers.txt for the peers protocol reference
  - doc/coding-style.txt for how to adopt HAProxy's coding style
  - doc/internals for developer-specific documentation (not all up to date)