1. Msilo Module

Daniel-Constantin Mierla

   FhG FOKUS

   Copyright © 2003 FhG FOKUS
     __________________________________________________________________

   1.1. Overview
   1.2. Dependencies

        1.2.1. SER modules

   1.3. Installation And Running

        1.3.1. SER Configuration File

   1.4. Parameters

        1.4.1. db_url (string)
        1.4.2. db_table (string)
        1.4.3. registrar (string)
        1.4.4. expire_time (int)
        1.4.5. check_time (int)
        1.4.6. clean_period (int)
        1.4.7. use_contact (int)

   1.5. Functions

        1.5.1. m_store(mode, next_hop)
        1.5.2. m_dump(next_hop)

1.1. Overview

   This modules provides offline message storage for SER. It stores
   received messages for an offline user and sends them when the user
   becomes online.

   For each message, the modules stores "Request-URI" ("R-URI") only if it
   is a complete address of record ("username@hostname"), URI from "To"
   header, URI from "From" header, incoming time, expiration time, content
   type and body of the message. If "R-URI" is not an address of record
   (it might be the contact address for current SIP session) the URI from
   "To" header will be used as R-URI.

   When the expiration time passed, the message is discarded from
   database. Expiration time is computed based on incoming time and one of
   the module's parameters.

   Every time when a user registers with SER, the module is looking in
   database for offline messages intended for that user. All of them will
   be sent to contact address provided in REGISTER request.

   It may happen the SIP user to be registered but his SIP User Agent to
   have no support for MESSAGE request. In this case it should be used the
   "failure_route" to store the undelivered requests.

1.2. Dependencies

1.2.1. SER modules

   The following modules must be loaded before this module:
     * database module - mysql, dbtext or other module that implements the
       "db" interface and provides support for storing/receiving data
       to/from a database system.
     * tm - Transaction module is used to send SIP requests.

1.3. Installation And Running

1.3.1. SER Configuration File

   Configuration example for msilo module.

   Example 1. SER Configuration Example
#
# MSILO usage example
#
#


debug=9           # debug level (cmd line: -dddddddddd)
fork=no           # don't fork
log_stderror=yes  # log to stderr (cmd line: -E)


children=2        # number of children
check_via=no      # (cmd. line: -v)
dns=off           # (cmd. line: -r)
rev_dns=off       # (cmd. line: -R)
port=5060

listen=127.0.0.1   # listen address

# ------------------ module loading ----------------------------------

loadmodule "../sip_router/modules/print/print.so"
loadmodule "../sip_router/modules/textops/textops.so"

loadmodule "../sip_router/modules/sl/sl.so"
loadmodule "../sip_router/modules/mysql/mysql.so"
loadmodule "../sip_router/modules/maxfwd/maxfwd.so"
loadmodule "../sip_router/modules/msilo/msilo.so"
loadmodule "../sip_router/modules/tm/tm.so"
loadmodule "../sip_router/modules/registrar/registrar.so"
loadmodule "../sip_router/modules/usrloc/usrloc.so"

# ----------------- setting module-specific parameters ---------------

# -- registrar params --

modparam("registrar", "default_expires", 120)

# -- registrar params --

modparam("usrloc", "db_mode", 0)

# -- msilo params --

modparam("msilo","db_url","mysql://user:xxx@127.0.0.1/msilo")
modparam("msilo","registrar","sip:registrar@mydomain.com")

# -- tm params --

modparam("tm", "fr_timer", 10 )
modparam("tm", "fr_inv_timer", 15 )
modparam("tm", "wt_timer", 10 )


route{
    if ( !mf_process_maxfwd_header("10") )
    {
        sl_send_reply("483","To Many Hops");
        drop();
    };


    if (uri==myself)
    {
        # for testing purposes, simply okay all REGISTERs
        if (method=="REGISTER")
        {
            save("location");
            log("REGISTER received -> dumping messages with MSILO\n");

            # MSILO - dumping user's offline messages
            if (m_dump())
            {
                log("MSILO: offline messages dumped - if they were\n");
            }else{
                log("MSILO: no offline messages dumped\n");
            };
            break;
        };

        # domestic SIP destinations are handled using our USRLOC DB

        if(!lookup("location"))
        {
            if (! t_newtran())
               {
                sl_reply_error();
                break;
               };
            # we do not care about anything else but MESSAGEs
            if (!method=="MESSAGE")
            {
                if (!t_reply("404", "Not found"))
                {
                    sl_reply_error();
                };
                break;
            };
            log("MESSAGE received -> storing using MSILO\n");
            # MSILO - storing as offline message
            if (m_store("0"))
            {
                log("MSILO: offline message stored\n");
                if (!t_reply("202", "Accepted"))
                {
                    sl_reply_error();
                };
            }else{
                log("MSILO: offline message NOT stored\n");
                if (!t_reply("503", "Service Unavailable"))
                {
                    sl_reply_error();
                };
            };
            break;
        };
        # if the downstream UA does not support MESSAGE requests
        # go to failure_route[1]
        t_on_failure("1");
        t_relay();
        break;
    };

    # forward anything else
    t_relay();
}

failure_route[1] {
    # forwarding failed -- check if the request was a MESSAGE
    if (!method=="MESSAGE")
    {
        break;
    };

    log(1,"MSILO:the downstream UA doesn't support MESSAGEs\n");
    # we have changed the R-URI with the contact address, ignore it now
    if (m_store("1"))
    {
        log("MSILO: offline message stored\n");
        t_reply("202", "Accepted");
    }else{
        log("MSILO: offline message NOT stored\n");
        t_reply("503", "Service Unavailable");
    };
}



1.4. Parameters

1.4.1. db_url (string)

   Database URL.

   Default value is "mysql://root@localhost/msilo".

   Example 2. Set the "db_url" parameter
...
modparam("msilo", "db_url", "mysql://user:passwd@host.com/dbname")
...

1.4.2. db_table (string)

   The name of table where to store the messages.

   Default value is "silo".

   Example 3. Set the "db_table" parameter
...
modparam("msilo", "db_table", "silo")
...

1.4.3. registrar (string)

   The SIP address used to inform users that destination of their message
   is not online and the message will be delivered next time when that
   user goes online. If the parameter is not set, the module will not send
   any notification. All requests intended for this SIP address will not
   be stored for lately delivery.

   Default value is "NULL".

   Example 4. Set the registrar parameter
...
modparam("msilo", "registrar", "sip:registrar@iptel.org")
...

1.4.4. expire_time (int)

   Expire time of stored messages - seconds. When this time passed, the
   message is silently discarded from database.

   Default value is 259200 (72 hours = 3 days).

   Example 5. Set the expire_time parameter
...
modparam("msilo", "expire_time", 36000)
...

1.4.5. check_time (int)

   Timer interval to check if dumped messages are sent OK - seconds. The
   module keeps each request send by itself for a new online user and if
   the reply is 2xx then the message is deleted from database.

   Default value is 30.

   Example 6. Set the check_time parameter
...
modparam("msilo", "check_time", 10)
...

1.4.6. clean_period (int)

   Number of check_time cycles when to check if there are expired messages
   in database.

   Default value is 5.

   Example 7. Set the clean_period parameter
...
modparam("msilo", "clean_period", "3")
...

1.4.7. use_contact (int)

   Turns on/off the usage of the Contact address to send notification back
   to sender whose message is stored by MSILO.

   Default value is 1 (0 = off, 1 = on).

   Example 8. Set the param_name parameter
...
modparam("msilo", "use_contact", 0)
...

1.5. Functions

1.5.1. m_store(mode, next_hop)

   The method stores certain parts of the current SIP request (it should
   be called when the request type is MESSAGE and the destination user is
   offline or his UA does not support MESSAGE requests). If the user is
   registered with a UA which does not support MESSAGE requests you should
   not use mode="0" if you have changed the request uri with the contact
   address of user's UA.

   Meaning of the parameters is as follows:
     * mode - specifies what to save as R-URI.
          + "0" - first check if new_uri is an address of record. If yes,
            then use it and store it as R-URI, otherwise look at R-URI
            and, if necessary, at URI from "To" header.
          + "1" - look first at R-URI and then at URI from "To" header.
          + "2" - look only at URI form "To" header.
     * next_hop (optional) - specifies next hop for sending outgoing
       messages (use as "outbound proxy"). Its value can be unset, empty
       or set to a sip URI like "sip:127.0.0.1:5060".

1.5.2. m_dump(next_hop)

   The method sends stored messages for the SIP user that is going to
   register to his actual contact address. The method should be called
   when a REGISTER request is received and the "Expire" header has a value
   greater than zero. The parameter can contain machine used as "outbound
   proxy" or can be empty.

   Meaning of the parameters is as follows:
     * next_hop (optional) - specifies next hop for sending outgoing
       messages (use as "outbound proxy"). Its value can be unset, empty
       or set to a sip URI like "sip:127.0.0.1:5060".