SipTrace Module

Daniel-Constantin Mierla

Edited by

Alexandr Dubovikov

Daniel-Constantin Mierla

Giacomo Vacca

Camille Oudot

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. db_url (str)
3.2. table (str)
3.3. trace_flag (integer)
3.4. trace_on (integer)
3.5. traced_user_avp (str)
3.6. trace_table_avp (str)
3.7. duplicate_uri (str)
3.8. trace_to_database (integer)
3.9. trace_local_ip (str)
3.10. trace_sl_acks (integer)
3.11. xheaders_write (integer)
3.12. xheaders_read (integer)
3.13. hep_mode_on (integer)
3.14. hep_version (integer)
3.15. hep_capture_id (integer)
3.16. trace_delayed (integer)
3.17. force_send_sock (str)
3.18. trace_mode (integer)
3.19. auth_key (integer)
4. Functions
4.1. sip_trace([address][,correlation_id][,mode])
4.2. sip_trace_mode(tmode)
4.3. hlog([correlation_id,] message)
5. RPC Commands
5.1. siptrace.status param
6. Database setup
7. Known issues

List of Examples

1.1. Set db_url parameter
1.2. Set table parameter
1.3. Set trace_flag parameter
1.4. Set trace_on parameter
1.5. Set traced_user_avp parameter
1.6. Set trace_table_avp parameter
1.7. Set duplicate_uri parameter
1.8. Set trace_to_database parameter
1.9. Set trace_local_ip parameter
1.10. Set trace_sl_acks parameter
1.11. Set xheaders_write parameter
1.12. Set xheaders_read parameter
1.13. Set hep_mode_on parameter
1.14. Set hep_version parameter
1.15. Set hep_capture_id parameter
1.16. Set trace_delayed parameter
1.17. Set force_send_sock parameter
1.18. Set trace_mode parameter
1.19. Set auth_key parameter
1.20. sip_trace() usage
1.21. sip_trace_mode() usage
1.22. hlog() usage
1.23. Send relayed ACK message

Chapter 1. Admin Guide

1. Overview

The SIPtrace module offer a possibility to store incoming and outgoing SIP messages in a database and/or duplicate to the capturing server (using HEP, the Homer encapsulation protocol, or plain SIP mode). Since version 5.3.0 new levels of tracing are available. Transactions and dialogs can be traced.

There are multiple ways of storing information:

  • by calling the sip_trace() method explicitly in the Kamailio configuration file. In this case the original message is processed along with it's corresponding transaction/dialog if certain flags are used.

  • by setting trace_mode to mirror all traffic.

The tracing can be turned on/off using Kamailio RPC commands.

kamctl fifo sip_trace on

kamctl fifo sip_trace off

2. Dependencies

2.1. Kamailio Modules

The following modules must be conditionally loaded before this module:

  • A database module - Mysql, Postgres, dbtext, unixODBC... Optional, if tracing to DB is enabled.

  • dialog, tm and sl modules - optional, only if you want to trace messages forwarded by these modules.

2.2. External Libraries or Applications

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

  • None.

3. Parameters

3.1. db_url (str)

Database URL.

Default value is "mysql://kamailio:kamailiorw@localhost/kamailio".

Example 1.1. Set db_url parameter

modparam("siptrace", "db_url", "dbdriver://username:password@dbhost/dbname")

3.2. table (str)

Name of the table where to store the SIP messages.

Default value is sip_trace.

Example 1.2. Set table parameter

modparam("siptrace", "table", "strace")

3.3. trace_flag (integer)

Which flag is used to mark messages to trace without traced user.

Default value is "0".

Example 1.3. Set trace_flag parameter

modparam("siptrace", "trace_flag", 22)

3.4. trace_on (integer)

Parameter to enable/disable trace (on(1)/off(0))

Default value is "0".

Example 1.4. Set trace_on parameter

modparam("siptrace", "trace_on", 1)

3.5. traced_user_avp (str)

The name of the AVP storing the SIP URI of the traced user. If the AVP is set, messages are stored in database table and the traced_user column is filled with AVP's value. You can store the message many times for many users by having multiple values for this AVP.

Default value is "NULL" (feature disabled).

Example 1.5. Set traced_user_avp parameter

modparam("siptrace", "traced_user_avp", "$avp(i:123)")
modparam("siptrace", "traced_user_avp", "$avp(s:user)")

3.6. trace_table_avp (str)

The name of the AVP storing the name of the table where to store the SIP messages. If it is not set, the value of table parameter is used. In this way one can select dynamically where to store the traced messages. The table must exist, and must have the same structure as the sip_trace table.

Default value is "NULL" (feature disabled).

Example 1.6. Set trace_table_avp parameter

modparam("siptrace", "trace_table_avp", "$avp(i:345)")
modparam("siptrace", "trace_table_avp", "$avp(s:siptrace_table)")

3.7. duplicate_uri (str)

The address in form of a SIP URI where to send a duplicate of traced message. It uses UDP all the time.

Default value is "NULL".

Example 1.7. Set duplicate_uri parameter

modparam("siptrace", "duplicate_uri", "sip:")

3.8. trace_to_database (integer)

Parameter to enable/disable inserts to the database from this Kamailio.

In case we only want to send the SIP messages to the duplicate_uri and not store the information to the local database we can set this to "0".

Default value is "1".

Example 1.8. Set trace_to_database parameter

modparam("siptrace", "trace_to_database", 0)

3.9. trace_local_ip (str)

The address to be used in fromip field for locally generated messages. If not set, the module sets it to the address of the socket that will be used to send the message.

Default value is "NULL".

Example 1.9. Set trace_local_ip parameter

modparam("siptrace", "trace_local_ip", "")

3.10. trace_sl_acks (integer)

Parameter to enable/disable tracing of SL-filtered ACKs (on=1 / off=0).

By default all ACKs to replies generated by SL module are traced. There is no way to select among them. The SL module is able to run an event route when such an ACK arrives (event_route[sl:filtered-ack]). You can set this parameter to 0 and then execute sip_trace() in the event route, accompanied by config rules to decide which ACK to trace.

Default value is "1".

Example 1.10. Set trace_sl_acks parameter

modparam("siptrace", "trace_sl_acks", 0)

3.11. xheaders_write (integer)

Parameter to enable/disable writing of x-headers.

Stores fromip, toip, method and direction in X-Siptrace-* headers. This allows to transmit them to a second Kamailio server using the duplicate_uri feature. Because the headers are added after the data is written to the database, the headers only show up in the packets sent by duplicate_uri.

See xheaders_read, it should be used on the receiving side.

Note: The headers are first read, then written. This allows relaying the information over more than two Kamailio servers by setting both xheaders_write and xheaders_read to "1" on the servers in the middle.

Default value is "0".

Example 1.11. Set xheaders_write parameter

modparam("siptrace", "xheaders_write", 0)

3.12. xheaders_read (integer)

Parameter to enable/disable reading of x-headers.

Reads and removes the X-Siptrace-* headers. Packets not containing the headers are neither stored to the database nor relayed (duplicate_uri). See xheaders_write for further information.

Default value is "0".

Example 1.12. Set xheaders_read parameter

modparam("siptrace", "xheaders_read", 0)

3.13. hep_mode_on (integer)

Parameter to enable/disable Homer encapsulate mode (on(1)/off(0))

Default value is "0".

Example 1.13. Set hep_mode_on parameter

modparam("siptrace", "hep_mode_on", 1)

3.14. hep_version (integer)

The parameter indicate the version of the HEP protocol. Can be 1, 2 or 3. In HEPv2 and HEPv3 the timestamp and capture agent ID will be included in the HEP header.

Default value is "1".

Example 1.14. Set hep_version parameter

modparam("siptrace", "hep_version", 3)

3.15. hep_capture_id (integer)

The parameter indicate the capture agent ID for the HEPv2 or HEPv3 protocol. Limitation: 16-bit integer for HEPv2, 32-bit for HEPv3.

Default value is "1".

Example 1.15. Set hep_capture_id parameter

modparam("siptrace", "hep_capture_id", 234)

3.16. trace_delayed (integer)

Use INSERT DELAYED to store to database when it is available, instead of INSERT.

Default value is 0 (off).

Example 1.16. Set trace_delayed parameter

modparam("siptrace", "trace_delayed", 1)

3.17. force_send_sock (str)

The local interface in the form of SIP URI from where to send the duplicated traffic. In the absence of this parameter Kamailio automatically picks an interface. This parameter is only used for HEP forwarding, not for SIP forwarding mode.

Example 1.17. Set force_send_sock parameter

modparam("siptrace", "force_send_sock", "sip:")

3.18. trace_mode (integer)

If set to 1, the module uses core events triggered when receiving or sending SIP traffic to mirror traffic to a SIP capture server using HEP. It will automatically do the mirroring of all SIP traffic. It is no longer needed to set the siptrace flag per request or execute sip_trace(), if it is done, then there mirroring is duplicated.

If set to 0, no automatic mirroring of SIP traffic via HEP.

Default value is 0.

Example 1.18. Set trace_mode parameter

modparam("siptrace", "trace_mode", 1)

3.19. auth_key (integer)

A string with an authorization key. Supported on HEPv3 only.

Default value is empty.

Example 1.19. Set auth_key parameter

modparam("siptrace", "auth_key", "spoihepuirthpeuia")

4. Functions

4.1.  sip_trace([address][,correlation_id][,mode])

Store or forward the current processed SIP message/transaction/dialog in database. It is stored in the form prior applying changes made to it. Based on mode, one can trace the current message('m'), the current transaction('t') or the current dialog('d'). If no mode is given, it falls back to the default mode - transaction tracking when trace_flag is set, otherwise only the current message.

Meaning of the parameters is as follows:

  • address - The address in form of SIP URI where to send a duplicate of traced message. This parameter trumps duplicate_uri and allows tracing to more than one server.

  • correlation_id - A string with a correlation ID to be added to the HEP header when using HEPv3. It's possible to use PVs.

  • mode - SIP messages to be traced. One can trace the current message (function can be called on either a reply or a request), the current transaction(the route must belong to a request) or the current dialog(the message has to be an invite).


Default value is "NULL".

Example 1.20. sip_trace() usage

sip_trace("sip:", "$ci-abc");
/* trace current dialog; needs to be done on initial INVITE and dialog has to be loaded */
sip_trace("sip:", "$ci-abc", "d");

4.2.  sip_trace_mode(tmode)

Set the tracing mode: message, transaction or dialog. Only the first character of the parameter matters: m or M for message; t or T for transaction; d or D for dialog.

In message tracing mode only the current message is stored or mirrored. In transaction tracing mode, all the messages of the current transaction are stored or mirrored. In dialog tracing mode, all the messages of the current dialog are stored or mirrored.

This function can be used in ANY_ROUTE.

Example 1.21. sip_trace_mode() usage


4.3.  hlog([correlation_id,] message)

Sends a log event as a HEP3 packet to the homer host configured in duplicate_uri.

Meaning of the parameters is as follows:

  • correlation_id (optional) - Homer correlation ID for this event. If this parameter is not set, the current message's call-id will be used. (This parameter may contain PVs)

  • message - The text to send to Homer as log event. (This parameter may contain PVs)

Example 1.22. hlog() usage

hlog("[cfg:$cfg(line)] This is a log from kamailio to Homer");
hlog("$hdr(P-MyID)", "Another one with a custom correlation ID");

5. RPC Commands

5.1.  siptrace.status param

Name: siptrace.status


  • on or off: turns on/off SIP message tracing. Possible values are:

    • on

    • off

  • check does not change siptrace status, just reports the current status.

RPC Command Format:

kamcmd siptrace.status on
kamcmd siptrace.status off
kamcmd siptrace.status check

6. Database setup

Before running Kamailio with siptrace and activated trace_to_database parameter, you have to setup the database tables where the module will store the data. For that, if the table were not created by the installation script or you choose to install everything by yourself you can use the siptrace-create.sql SQL script in the database directories in the kamailio/scripts folder as template. You can also find the complete database documentation on the project webpage,

7. Known issues

Stateless forwarded messages (forward()) are not logged if you set the flag, use sip_trace() inside onsend_route block.

If dialog level tracing is used internally generated BYE transaction(in case of internal timeouts) won't be traced. At the moment kamailio offers no posibility to trace those messages.

Trace_info xavp name is reserved by this module. Any use of xavp with this name will result in overlapping internal avp used by the module therefore causing unknown consequences.

Example 1.23. Send relayed ACK message

onsend_route {
    if (is_method("ACK")) {