[sr-dev] git:master: tm: Number of fixes in code and documentation for serial forking.

Sun Oct 18 01:12:20 CEST 2009

Hello Juha,

This commit includes a number of changes I have done to the serial
forking code in tm. The original version crashed sip-router and timers
and other things did not work properly. I have tested the code and it
seems to be working fine now, including all the things we discussed in
other threads.

There is only one incompatible change. The value of fr_inv_timer_next
is now in milliseconds. The previous version used seconds, but it did
not work in sip-router anyway. All other tm timers use milliseconds,
so we are now consistent.

I merged this commit also into sr_3.0 branch, because in addition to
the new documentation this is all bugfixes. I think that this commit
should also be merged into kamailio_3.0 branch, because the original
code does not seem to work well with sip-router core.

I am also going to add support for serial forking to the all-inclusive
config file in  sip-router-oob.cfg. I have been waiting for q based
serial forking for years, but never managed to pull myself together
and actually implement it :-).

Please give it a try in your configuration if you have the time and
let me know if something does not work.

  -- Jan

On Sun, Oct 18, 2009 at 12:45 AM, Jan Janak <jan at iptel.org> wrote:
> Module: sip-router
> Branch: master
> Commit: ed3902e9bd5a3af6ee5d5df08ce2564f028a0f24
> URL:    http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=ed3902e9bd5a3af6ee5d5df08ce2564f028a0f24
>
> Author: Jan Janak <jan at ryngle.com>
> Committer: Jan Janak <jan at ryngle.com>
> Date:   Sun Oct 18 00:39:31 2009 +0200
>
> tm: Number of fixes in code and documentation for serial forking.
>
> This patch improves the serial forking related code and documentation.
> The original code suffers from shortcommits, some of which were result
> of the migration to the new core.
>
> The function that decodes destination sets encoded in AVPs has been
> improved, because the original version did not handle properly strings
> with missing elements. In such case the original implementation was
> likely to overwrite memory, because it did not check the return value
> of strchr properly. The new implementation tries to handle this
> situation. It continues parsing as long as it can, it only requires
> that the request-uri string is present, all other fields are made
> optional and their variables are properly initialized if their values
> cannot be found in the AVP.
>
> There was a bug in the implementation of fr_inv_timer_next modparam in
> the original version, changes to the parameter value were ignored by
> the serial forking code. This was reported by Andrei and is now fixed
> by this commit. The parameter fr_inv_timer_next can now be configured
> at runtime with the configuration framework. Its value is in
> milliseconds and unlike fr_inv_timer, this timer cannot be configured
> separately for individual branches.
>
> Obsolete definition of INV_FR_TIME_OUT_FIRST has been removed. That
> macro is not used anywhere in the code, thus it is not needed.
>
> There were several places where LM_DBG printed a string and relied on
> the string being zero terminated, this may or may not be true in the
> future and this patch uses the macro STR_FMT where appropriate, which
> is safer.
>
> Function t_next_contacts now checks if the function decode_branch_info
> really returned values for the dst_uri and the path vector. If not then
> it calls reset_dst_uri and reset_path_vector. Previous version of the
> code crashed sip-router, this is likely due to the merge and updates in
> the sip-router core.
>
> We now use t_set_fr in t_next_contacts for setting the fr_inv_timer
> value to fr_inv_timer_next. This is much more efficient than creating
> AVPs with new timer values. Also the new value of the timer is now
> taken from a variable in the configuration framework, instead of just a
> regular global variable configured through modparam. This way we can
> adjust the value of the timer on the fly. Configuring it through
> modparam is, of course, possible too.
>
> The value of of fr_inv_timer_next is now in milliseconds, instead of
> seconds. That's the only possibly incompatible change. However, this is
> consistent with all other timers in tm module, it is more efficient and
> it offers better granularity.
>
> A missing call to destroy_avp has been added to t_next_contacts, in the
> code which is executed when no transaction exists. There, the avp
> should also be destroyed if all values have been exhausted and none of
> them had Q_FLAG set. This is a corner case which should not happen
> under normal circumstances, because that situation only happens if all
> branches have the same q value. Such AVP would not have been created by
> t_load_contacts and therefore t_next_contacts should not be called, but
> this bug may be triggered if someone uses t_next_contacts in an
> unexpected way and it is probably better to have it fixed.
>
> Also the code which restores the value of fr_inv_timer at the end of
> t_next_contacts did not work properly. This patch fixes that. It first
> tries to retrieve a value configured with t_set_fr, but that is not
> guaranteed to succeed. After that it also tries the timer AVP and
> finally the configuration framework. The configuration framework always
> yields a value, so we can always restore the timer value, but we may
> fail to restore individual transaction timer values set by t_set_fr. If
> that fails then the global value from the configuration framework is
> used. This is documented as a shortcomming in the README and in the
> code.
>
> In addition to code changes this patch also expands documentation on
> functions t_load_contacts and t_next_contacts, describing their
> operation in more detail. Also the format of the contacts AVP is now
> documented.
>
> Finally, there is a whole new section in the README which describes
> how serial/parallel forking can be achieved with t_load_contacts and
> t_next_contacts and provides a number of examples.
>
> ---
>
>  modules/tm/README            |  592 +++++++++++++++++++++++++++---------------
>  modules/tm/config.c          |    7 +-
>  modules/tm/config.h          |    3 +-
>  modules/tm/doc/functions.xml |  129 ++++++++--
>  modules/tm/doc/params.xml    |   83 +++++--
>  modules/tm/doc/tm.xml        |  218 ++++++++++++++++
>  modules/tm/t_serial.c        |  208 ++++++++++------
>  modules/tm/tm.c              |    2 +-
>  8 files changed, 900 insertions(+), 342 deletions(-)
>
> Diff:   http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commitdiff;h=ed3902e9bd5a3af6ee5d5df08ce2564f028a0f24
>
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