Accounting and CDRs

Accounting records what happened on the server: who called whom, when the call started and ended, and how the transaction finished. Kamailio produces these records with the acc module, which can write to syslog, to a database, or to an external system such as RADIUS or DIAMETER.

Accounting is driven by flags set during routing rather than by a global switch. Three flags decide what is recorded:

#!define FLT_ACC 1          # account the transaction
#!define FLT_ACCMISSED 2    # account calls that were never answered
#!define FLT_ACCFAILED 3    # account transactions that ended with a failure reply

Files

Log accounting

The minimal setup only needs acc.so loaded and a flag set on the requests to be accounted:

loadmodule "acc.so"

modparam("acc", "log_flag", FLT_ACC)
modparam("acc", "log_missed_flag", FLT_ACCMISSED)
modparam("acc", "failed_transaction_flag", FLT_ACCFAILED)
modparam("acc", "log_extra",
    "src_user=$fU;src_domain=$fd;src_ip=$si;dst_ouser=$tU;dst_user=$rU;dst_domain=$rd")

request_route {
    # account only INVITEs
    if (is_method("INVITE")) {
        setflag(FLT_ACC);
    }
    ...
}

log_extra controls which pseudo-variables end up in the record beyond the defaults. Because the values are read when the transaction completes, use variables that are still meaningful at that point.

Database accounting

Writing to MySQL only changes where the record goes; the flags stay the same:

#!define WITH_ACCDB

modparam("acc", "db_flag", FLT_ACC)
modparam("acc", "db_missed_flag", FLT_ACCMISSED)
modparam("acc", "db_url", DBURL)

The stock acc table does not have columns for the extra fields, so add them before enabling db_extra:

ALTER TABLE acc ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT '';
ALTER TABLE acc ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT '';
ALTER TABLE acc ADD COLUMN src_ip varchar(64) NOT NULL default '';
ALTER TABLE acc ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT '';
ALTER TABLE acc ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT '';
ALTER TABLE acc ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT '';

The same statements are needed on the missed_calls table if missed call accounting is enabled.

What gets accounted

• early_media records 183 Session Progress as an answer. Off by default, since it inflates answered call counts.
• report_ack and report_cancels add records for ACK and CANCEL, useful for debugging but noisy in production.
• detect_direction decides whether the caller is taken from the From header or from the direction of the request, which matters for in-dialog BYEs.

Related examples

• mos_cdr_accmodule writes voice quality scores next to the CDR.
• mos_rtpstats_rtpengine derives MOS from RTCP statistics.
• mysql_user_stoarge covers the MySQL schema setup with kamctl.

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