Jiri Kuthan
iptel.org
jiri@iptel.org
2002 2003 FhG FOKUS

# Acc Module

## Overview

acc module is used to report on transactions to syslog, SQL and RADIUS.

To report on a transaction using syslog, use "setflag" to mark a transaction you are interested in with a flag, load accounting module and set its "log_flag" to the same flag number. The acc module will then report on completed transaction to syslog. A typical usage of the module takes no acc-specific script command -- the functionality binds invisibly through transaction processing. Script writers just need to mark the transaction for accounting with proper setflag.

What is printed depends on module's "log_fmt" parameter. It's a string with characters specifying which parts of request should be printed:

- c = Call-Id

- d = To tag (Dst)

- f = From

- i = Inbound Request-URI

- m = Method

- o = Outbound Request-URI

- r = fRom

- s = Status

- t = To

- u = digest Username

- p = username Part of inbound Request-URI

If a value is not present in request, "n/a" is accounted instead.

- A single INVITE may produce multiple accounting reports -- that's due to SIP forking feature

- Subsequent ACKs and other requests do not hit the server and can't be accounted unless record-routing is enforced. The ACKs assert very little useful information anyway and reporting on INVITE's 200 makes most accounting scenarios happy.

- There is no session accounting -- ser maintains no sessions. If one needs to correlate INVITEs with BYEs for example for purpose of billing, then it is better done in the entity which collects accounting information. Otherwise, SIP server would have to become sessions-stateful, which would very badly impact its scalability.

- If a UA fails in middle of conversation, a proxy will never learn it. In general, a better practice is to account from an end-device (such as PSTN gateway), which best knows about call status (including media status and PSTN status in case of the gateway).

Support for SQL and RADIUS works analogously. You need to enable it by recompiling the module with properly set defines. Uncomment the SQL_ACC and RAD_ACC lines in `modules/acc/Makefile`. To compile SQL support, you need to have mysqlclient package on your system. To compile RADIUS support, you need to have radiusclient installed on your system (version 0.5.0 or higher is required) which is available from http://developer.berlios.de/projects/radiusclient-ng/. The radius client needs to be configured properly. To do so, use the template in `sip_router/etc/radiusclient.conf` and make sure that module's `radius_config` parameter points to its location. Uses along with FreeRADIUS and Radiator servers have been reported to us.

Both mysql and radius libraries must be dynamically linkable. You need to configure your OS so that SER, when started, will find them. Typically, you do so by manipulating LD_LIBRARY_PATH environment variable or configuring ld.so.

General Example

    loadmodule "modules/acc/acc.so"
    modparam("acc", "log_level", 1)
    modparam("acc", "log_flag", 1)

    if (uri=~"sip:+49") /* calls to Germany */ {
        if (!proxy_authorize("iptel.org" /* realm */,
                             "subscriber" /* table name */))  {
            proxy_challenge("iptel.org" /* realm */, "0" /* no qop */ );
            break;
        }

        if (method=="INVITE" & !check_from()) {
            log("from!=digest\n");
            sl_send_reply("403","Forbidden");
            break;
        }

        setflag(1); /* set for accounting (the same value as in log_flag!)
        t_relay(); 	/* enter stateful mode now */
    };

## Dependencies

The module depends on the following modules (in the other words the listed modules must be loaded before this module):

- tm

  Transaction Manager

- A database module (mysql,postgres,dbtext)

  If compiled with database support.