MI_FIFO module

Admin Guide

Overview

This is a module which provides a FIFO transport layer implementation for Management Interface. It receives the command over a FIFO file and returns the output through the reply_fifo specified.

The module checks every 30 seconds if the FIFO file exists, and if it was deleted, it recreates it. If one wants to force the fifo file recreation, it should send a SIGHUP signal to the MI process PID.

FIFO command syntax

The external commands issued via FIFO interface must follow the following syntax: request = ’:‘(reply_fifo)?’:‘jsonrpc_command

If the reply_fifo is missing, the MI FIFO module will not send any reply back. A similar behavior happens when the jsonrpc_command does not contain the id element, and the command is considered a JSON-RPC notification.

Values Returned

In case of success, a valid JSON-RPC response is replied back on the fifo file, containing a successful JSON-RPC response.

In case of failure of the MI command, a JSON-RPC reply error is sent back over the reply fifo file.

If case of an error generated by the MI engine, mostly internal errors, an error cause is sent back over the reply FIFO in plain text.

Dependencies

OpenSIPS Modules

The following modules must be loaded before this module:

• No dependencies on other OpenSIPS modules.

External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

• none

Exported Parameters

fifo_name (string)

The name of the FIFO file to be created for listening and reading external commands.

Note

Starting with Linux kernel 4.19, processes can no longer read from FIFO files that are saved in directories with sticky bits (such as /tmp) and are not owned by the same user the process runs with. This prevents external tools (such as opensips-cli) from running MI commands using a different user (a Permissions denied error is triggered). If you are getting this error while trying to use opensips-cli, you can fix it by either store the fifo file in a non-sticky bit directory (such as /run/opensips), or disable the fifo protection using sysctl fs.protected_fifos = 0 (NOT RECOMMENDED).

Default value is “/tmp/opensips_fifo”.

Set fifo_name parameter

...
modparam("mi_fifo", "fifo_name", "/tmp/opensips_b2b_fifo")
...

fifo_mode (integer)

Permission to be used for creating the listening FIFO file. It follows the UNIX conventions.

Default value is 0660 (rw-rw----).

Set fifo_mode parameter

...
modparam("mi_fifo", "fifo_mode", 0600)
...

fifo_group (integer) fifo_group (string)

Group to be used for creating the listening FIFO file.

Default value is the inherited one.

Set fifo_group parameter

...
modparam("mi_fifo", "fifo_group", 0)
modparam("mi_fifo", "fifo_group", "root")
...

fifo_user (integer) fifo_group (string)

User to be used for creating the listening FIFO file.

Default value is the inherited one.

Set fifo_user parameter

...
modparam("mi_fifo", "fifo_user", 0)
modparam("mi_fifo", "fifo_user", "root")
...

reply_dir (string)

Directory to be used for creating the reply FIFO files.

Default value is “/tmp/“

Set reply_dir parameter

...
modparam("mi_fifo", "reply_dir", "/home/opensips/tmp/")
...

pretty_printing (int)

Indicates whether the JSONRPC responses sent through MI should be pretty-printed or not.

Default value is “0 - no pretty-printing”.

Set pretty_printing parameter

...
modparam("mi_fifo", "pretty_printing", 1)
...

trace_destination (string)

Trace destination as defined in the tracing module. Currently the only tracing module is proto_hep. This is where traced mi messages will go.

**WARNING:**A tracing module must be loaded in order for this parameter to work. (for example proto_hep).

Default value is none(not defined).

Set trace_destination parameter

...
modparam("proto_hep", "trace_destination", "[hep_dest]10.0.0.2;transport=tcp;version=3")

modparam("mi_fifo", "trace_destination", "hep_dest")
...

trace_bwlist (string)

Filter traced mi commands based on a blacklist or a whitelist. trace_destination must be defined for this parameter to have any purpose. Whitelists can be defined using ‘w’ or ‘W’, blacklists using ‘b’ or ‘B’. The type is separate by the actual blacklist by ’:’. The mi commands in the list must be separated by ’,’.

Defining a blacklists means all the commands that are not blacklisted will be traced. Defining a whitelist means all the commands that are not whitelisted will not be traced. WARNING: One can’t define both a whitelist and a blacklist. Only one of them is allowed. Defining the parameter a second time will just overwrite the first one.

Danger

A tracing module must be loaded in order for this parameter to work. (for example proto_hep).

Default value is none(not defined).

Set trace_destination parameter

...
## blacklist ps and which mi commands
## all the other commands shall be traced
modparam("mi_fifo", "trace_bwlist", "b: ps, which")
...
## allow only sip_trace mi command
## all the other commands will not be traced
modparam("mi_fifo", "trace_bwlist", "w: sip_trace")
...

Exported Functions

No function exported to be used from configuration file.

Example

This is an example showing the FIFO format for the “get_statistics dialog: tm:” MI commad: response.

FIFO request

:reply_fifo:{"jsonrpc":"2.0","method":"get_statistics","id":"5672","params":[["dialog:","tm:"]]}

Contributors

By Commit Statistics

Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

#	Name	DevScore	Commits	Lines++	Lines—
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	65	37	2437	396
2.	Razvan Crainea (@razvancrainea)	43	20	584	1074
3.	Liviu Chircu (@liviuchircu)	17	14	49	88
4.	Daniel-Constantin Mierla (@miconda)	12	10	20	22
5.	Stefan Darius (@dariusstefan)	10	4	363	77
6.	Ionut Ionita (@ionutrazvanionita)	7	4	228	39
7.	Maksym Sobolyev (@sobomax)	5	3	16	18
8.	Henning Westerholt (@henningw)	5	2	62	109
9.	Zero King (@l2dy)	3	1	5	3
10.	Jerome Martin	3	1	3	3

All remaining contributors: Walter Doekes (@wdoekes), Konstantin Bokarius, Ovidiu Sas (@ovidiusas), Alexey Vasilyev (@vasilevalex), Peter Lemenkov (@lemenkov), Julián Moreno Patiño, Edson Gellert Schubert, Dusan Klinec (@ph4r05), Vlad Patrascu (@rvlad-patrascu).

(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)

(2) including any documentation-related commits, excluding merge commits

(3) ignoring whitespace edits, renamed files and auto-generated files

By Commit Activity

#	Name	Commit Activity
1.	Stefan Darius (@dariusstefan)	Jun 2026 - Jul 2026
2.	Razvan Crainea (@razvancrainea)	Feb 2012 - Jun 2026
3.	Liviu Chircu (@liviuchircu)	Mar 2014 - May 2024
4.	Maksym Sobolyev (@sobomax)	Feb 2021 - Feb 2023
5.	Alexey Vasilyev (@vasilevalex)	Mar 2022 - Mar 2022
6.	Bogdan-Andrei Iancu (@bogdan-iancu)	Oct 2006 - Apr 2021
7.	Zero King (@l2dy)	Mar 2020 - Mar 2020
8.	Peter Lemenkov (@lemenkov)	Jun 2018 - Jun 2018
9.	Vlad Patrascu (@rvlad-patrascu)	May 2017 - May 2017
10.	Ionut Ionita (@ionutrazvanionita)	Jan 2017 - Feb 2017

All remaining contributors: Julián Moreno Patiño, Dusan Klinec (@ph4r05), Walter Doekes (@wdoekes), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Ovidiu Sas (@ovidiusas), Henning Westerholt (@henningw), Jerome Martin.

(1) including any documentation-related commits, excluding merge commits

Documentation

Contributors

Last edited by: Razvan Crainea (@razvancrainea), Alexey Vasilyev (@vasilevalex), Liviu Chircu (@liviuchircu), Peter Lemenkov (@lemenkov), Ionut Ionita (@ionutrazvanionita), Bogdan-Andrei Iancu (@bogdan-iancu), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert, Jerome Martin.

License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0