This module performs destinations monitoring either for itself, or on the behalf of other modules. The monitoring is done by sending SIP OPTIONS requests, more or less in the same fashion as the dispatcher module (which was the initial source for this module).

As an example of usage by other modules, see drouting, which was enhanced to use this module to monitor its gateways.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

tm - Transaction module

2.2. External Libraries or Applications

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

none

2.3. Parameters

2.3.1. `ping_interval` (integer)

Define the interval (in seconds) ping requests are sent to destinations

Default value is 30 seconds.

Example 1.1. Set ping_interval parameter

...
modparam("keepalive", "ping_interval", 10)
...

2.3.2. `destination` (string)

Allows to statically define destinations you want to monitor

Example 1.2. Set destination parameter

...
modparam("keepalive", "destination", "192.168.10.20")
modparam("keepalive", "destination", "sip.provider.com")
...

2.3.3. `delete_counter`(int)

Unsuccessful attempts increase delete_counter. After passing it, keepalive module doesn't try to send options requests. Ignored if it's set to 0.

Default value is 5 .

Example 1.3. Set delete_counter parameter

...
modparam("keepalive", "delete_counter", "5")
...

2.3.4. `ping_from`(string)

Sets from header's uri.

Default value is "sip:keepalive@kamailio.org" .

Example 1.4. Set ping_from parameter

...
modparam("keepalive", "ping_from", "sip:keepalive@kamailio.org")
...

2.4. Functions

2.4.1. `ka_is_alive(destination)`

Get destination status.

The parameter destination is destination you want to check status

Returned value:

1 if destination is up
2 if destination is down
-1 on error

This function can be used from ANY_ROUTE.

Example 1.5. ka_is_alive() usage

...
if(ka_is_alive("192.168.10.20") == 1) {
  // do stuff
};
...

2.4.2. `ka_add_destination(sip_uri, owner)`

Adds SIP URI in the memory destinations list to perform keep alive to it.

Meaning of the parameters:

sip_uri (string) - address of destination to monitor. Valid format is [protoschema:]ip[:port], with: 'protoschema' being one of 'sip' or 'sips' (SIP over TLS) - if omitted, 'sip' is used by default; 'port' is optional (using default standard port 5060 for sip and 5061 for sips)
owner (string) - module name “owning” the destination (for informational purpose)

Returned value:

1 - successful
-1 - on error

This function can be used from REQUEST_ROUTE,BRANCH_ROUTE,ONREPLY_ROUTE.

Example 1.6. ka_add_destination(sip_uri, ownder) usage

...
$avp(duri1)="sip:192.168.1.10:5060;transport=tcp";
$avp(duri2)="sip:192.168.1.11:5061";
$avp(duri3)="sip:192.168.1.12"
ka_add_destination("$avp(duri3)", "config");
ka_add_destination("sip:192.168.1.10:5060;transport=tcp", "config");
...

2.4.3. `ka_del_destination(sip_uri, owner)`

Deletes the SIP URI from the memory destinations list used for monitoring.

Meaning of the parameters:

sip_uri (string) - address of monitored destination. Valid format is [protoschema:]ip[:port], with: 'protoschema' being one of 'sip' or 'sips' (SIP over TLS) - if omitted, 'sip' is used by default; 'port' is optional (using default standard port 5060 for sip and 5061 for sips)
owner (string) - module name “owning” the destination (for informational purpose)

Returned value:

1 - successful
-1 - on error

This function can be used from ANY_ROUTE.

Example 1.7. ka_del_destination(sip_uri, owner) usage

...
$avp(duri1)="sip:192.168.1.10:5060;transport=tcp";
$avp(duri2)="sip:192.168.1.11:5061";
$avp(duri3)="sip:192.168.1.12"
ka_del_destination("$avp(duri3)", "config");
ka_del_destination("sip:192.168.1.10:5060;transport=tcp", "config");
...

2.5. RPC Commands

2.5.1. `keepalive.list`

Lists destinations in memory.

Name: keepalive.list

Parameters: none

Example 1.8. keepalive.list RPC example

			 keepalive.list

2.5.2. `keepalive.add`

Adds destination in memory.

Name: keepalive.add

Parameters: sip_uri listname

Example 1.9. keepalive.add RPC example

			 keepalive.add sip:username@domain listname

2.5.3. `keepalive.del`

Deletes destination in memory.

Name: keepalive.del

Parameters: sip_uri listname

Example 1.10. keepalive.del RPC example

			 keepalive.del sip:username@domain listname

2.5.4. `keepalive.get`

Gets destination in memory.

Name: keepalive.get

Parameters: sip_uri listname

Example 1.11. keepalive.get RPC example

			 keepalive.get sip:username@domain listname

2.5.5. `keepalive.flush`

Deletes all destinations in memory.

Name: keepalive.flush

Parameters:

Example 1.12. keepalive.flush RPC example

			 keepalive.flush

Chapter 2. Developer Guide

Table of Contents

1. Available Functions

1.1. add_destination(uri, owner, flags, ping_interval, [statechanged_clb, response_clb, [user_attr]])
1.2. Examples

The KeepAlive module provides an internal API to be used by other Kamailio modules. This API offers support for destinations monitoring.

For internal (non-script) usage, the KeepAlive module offers to other module the possibility to register callback functions to be executed for each destination's status change.

1. Available Functions

1.1. `add_destination(uri, owner, flags, ping_interval, [statechanged_clb, response_clb, [user_attr]])`

This function registers a new destination to monitor. Monitoring of the destination starts as soon as it returns with success (0 value).

Meaning of the parameters is as follows:

uri (string) - address of destination to monitor. Valid format is [proto:]ip[:port], with:
- proto being one of sip or sips (SIP over TLS). If omitted, sip is used by default
- port being optional (using default standard port, 5060 for sip and 5061 for sips)
owner (string) - module name “owning” the destination (for information purpose)
flags (integer) - destination flags (unused for now, use 0 value)
ping_interval (integer) - Pinging interval in seconds for this destination
statechanged_clb (ka_statechanged_f, optional) - callback function, executed on destination's state change.

The callback function is of type void (*ka_statechanged_f)(str *uri, int state, void *user_attr);. Use NULL to set no callback.

destination's state value is one of:
- 0 - unknown state (this is the destination state at first, waiting first ping replies or timeout)
- 1 - destination is UP
- 2 - destination is DOWN
response_clb (ka_response_f, optional) - callback function, executed on destination's response provided.

The callback function is of type void (*ka_response_f)(str *uri, struct tmcb_params *ps, void *user_attr);. Use NULL to set no callback.

ps is a pack structure with all params passed to callback function. Defined in t_hooks.h
user_attr (void * pointer, optional) - If any callback function is setup, this parameter will be forwarded to it (or both callbacks in both are defined), as last parameter. Use NULL to set no user_attr parameter.

Returned values:

0 if ok
-1 if an error occurred

1.2. Examples

Example 2.1. Loading KeepAlive module's API from another module, adding a destination to monitor & registering a callback

...
#include "../keepalive/api.h"
...
keepalive_api_t ka_api;
...
...
/* loading keepalive API */
if (bind_keepalive( &ka_api ) != 0) {
    LM_ERR("can't load KeepAlive API\n");
    goto error;
}
...
...
/* callback function (on state changed) */
void my_state_changed_clb(str uri, int state, void *user_attr) {
	printf("%.*s new state is: %d\n", uri.len, uri.str, state)
}

/* callback function (on each response received) */
void my_response_clb(str *uri, struct tmcb_params *ps, void *user_attr) {
	printf("response [%d] from %.*s\n", ps->code, uri.len, uri.str)
}

if (ka_api.add_destination(dest, owner, 0, 60, my_state_changed_clb,
				my_response_clb, NULL) != 0) {
    LM_ERR("can't add destination\n");
    goto error;
}
...

KeepAlive Module

Guillaume Bour

Yasin CANER

Edited by

Guillaume Bour

Yasin CANER

Chapter 1. Admin Guide

1. Overview

2. Dependencies

2.1. Kamailio Modules

2.2. External Libraries or Applications

2.3. Parameters

2.3.1. ping_interval (integer)

2.3.2. destination (string)

2.3.3. delete_counter(int)

2.3.4. ping_from(string)

2.4. Functions

2.4.1. ka_is_alive(destination)

2.4.2. ka_add_destination(sip_uri, owner)

2.4.3. ka_del_destination(sip_uri, owner)

2.5. RPC Commands

2.5.1. keepalive.list

2.5.2. keepalive.add

2.5.3. keepalive.del

2.5.4. keepalive.get

2.5.5. keepalive.flush

Chapter 2. Developer Guide

1. Available Functions

1.1. add_destination(uri, owner, flags, ping_interval, [statechanged_clb, response_clb, [user_attr]])

1.2. Examples

2.3.1. `ping_interval` (integer)

2.3.2. `destination` (string)

2.3.3. `delete_counter`(int)

2.3.4. `ping_from`(string)

2.4.1. `ka_is_alive(destination)`

2.4.2. `ka_add_destination(sip_uri, owner)`

2.4.3. `ka_del_destination(sip_uri, owner)`

2.5.1. `keepalive.list`

2.5.2. `keepalive.add`

2.5.3. `keepalive.del`

2.5.4. `keepalive.get`

2.5.5. `keepalive.flush`

1.1. `add_destination(uri, owner, flags, ping_interval, [statechanged_clb, response_clb, [user_attr]])`