B2B_ENTITIES
Anca-Maria Vamanu
OpenSIPS
Edited by
Anca-Maria Vamanu
Copyright © 2009 Anca-Maria
Vamanu
Revision History
Revision $Revision: $ $Date: $
__________________________________________________________
Table of Contents
1. Admin Guide
1.1. Overview
1.2. Dependencies
1.2.1. OpenSIPS Modules
1.2.2. External Libraries or Applications
1.3. Exported Parameters
1.3.1. server_address (str)
1.3.2. server_hsize (int)
1.3.3. client_hsize (int)
1.3.4. script_req_route (str)
1.3.5. script_reply_route (str)
1.3.6. db_url (str)
1.3.7. update_period (int)
1.4. Exported Functions
2. Developer Guide
2.1. b2b_load_api(b2b_api_t* api)
2.2. server_new
2.3. client_new
2.4. send_request
2.5. send_reply
2.6. entity_delete
2.7. restore_logic_info
2.8. update_b2bl_param
List of Examples
1.1. Set server_address parameter
1.2. Set server_hsize parameter
1.3. Set client_hsize parameter
1.4. Set script_req_route parameter
1.5. Set script_repl_route parameter
1.6. Set db_url parameter
1.7. Set update_period parameter
2.1. b2b_api_t structure
Chapter 1. Admin Guide
1.1. Overview
The B2BUA implementation in OpenSIPS is separated in two
layers:
* a lower one(coded in this module)- which implements the
basic functions of a UAS and UAC
* a upper one - which represents the logic engine of B2BUA,
responsible of actually implementing the B2BUA services
using the functions offered by the low level.
This module stores records corresponding to the dialogs in
which the B2BUA is involved. It exports an API to be called
from other modules which offers functions for creating a new
dialog record, for sending requests or replies in one dialog
and will also notify the upper level module when a request or
reply is received inside one stored dialog. The records are
separated in two types: b2b server entities and b2b client
entities depending on the mode they are created. An entity
created for a received initial message will be a server entity,
while a entity that will send an initial request(create a new
dialog) will be a b2b client entity. The name corresponds to
the behavior in the first transaction - if UAS - server entity
and if UAC - client entity. This module does not implement a
B2BUA alone, but needs a B2B logic implementing module.
1.2. Dependencies
1.2.1. OpenSIPS Modules
* tm
1.2.2. External Libraries or Applications
The following libraries or applications must be installed
before running OpenSIPS with this module loaded:
* none
1.3. Exported Parameters
1.3.1. server_address (str)
The IP address of the machine that will be used as Contact in
the sent messages.
Example 1.1. Set server_address parameter
...
modparam("b2b_entities", "server_address", "sip:sa@10.10.10.10:5060")
...
1.3.2. server_hsize (int)
The size of the hash table that stores the b2b server entities.
It is the 2 logarithmic value of the real size.
Default value is "9" (512 records).
Example 1.2. Set server_hsize parameter
...
modparam("b2b_entities", "server_hsize", 10)
...
1.3.3. client_hsize (int)
The size of the hash table that stores the b2b client entities.
It is the 2 logarithmic value of the real size.
Default value is "9" (512 records).
Example 1.3. Set client_hsize parameter
...
modparam("b2b_entities", "client_hsize", 10)
...
1.3.4. script_req_route (str)
The name of the b2b script route that will be called when B2B
requests are received.
Example 1.4. Set script_req_route parameter
...
modparam("b2b_entities", "script_req_route", "b2b_request")
...
1.3.5. script_reply_route (str)
The name of the b2b script route that will be called when B2B
replies are received.
Example 1.5. Set script_repl_route parameter
...
modparam("b2b_entities", "script_reply_route", "b2b_reply")
...
1.3.6. db_url (str)
Database URL.
Example 1.6. Set db_url parameter
...
modparam("b2b_entities", "db_url", "mysql://opensips:opensipsrw@127.0.0.
1/opensips")
...
1.3.7. update_period (int)
The time interval at which to update the info in database.
Default value is "100".
Example 1.7. Set update_period parameter
...
modparam("b2b_logic", "update_period", 60)
...
1.4. Exported Functions
The module does not export functions to be used in
configuration script.
Chapter 2. Developer Guide
The module provides an API that can be used from other OpenSIPS
modules. The API offers the functions for creating and handing
dialogs. A dialog can be created on a receipt initial message,
and this will correspond to a b2b server entity, or initiated
by the server and in this case a client entity will be created
in b2b_entities module.
2.1. b2b_load_api(b2b_api_t* api)
This function binds the b2b_entities modules and fills the
structure the exported functions that will be described in
detail.
Example 2.1. b2b_api_t structure
...
typedef struct b2b_api {
b2b_server_new_t server_new;
b2b_client_new_t client_new;
b2b_send_request_t send_request;
b2b_send_reply_t send_reply;
b2b_entity_delete_t entity_delete;
b2b_restore_linfo_t restore_logic_info;
b2b_update_b2bl_param_t update_b2bl_param;
}b2b_api_t;
...
2.2. server_new
Field type:
...
typedef str* (*b2b_server_new_t) (struct sip_msg* ,b2b_notify_t , void*
param);
...
This function asks the b2b_entities modules to create a new
server entity record. The internal processing actually extracts
the dialog information from the message and constructs a record
that will be stored in a hash table. The second parameters is a
pointer to a function that the b2b_entities module will call
when a event will come for that dialog (a request or reply).
The third parameter is a pointer to a value that will be stored
and given as a parameter when the notify function will be
called(it has to be allocated in shared memory).
The return value is an identifier for the record that will be
mentioned when calling other functions that represent actions
in the dialog(send request, send reply).
The notify function has the following prototype:
...
typedef int (*b2b_notify_t)(struct sip_msg* msg, str* id, int type, void
* param);
...
This function is called when a request or reply is received for
a dialog handled by b2b_entities. The first parameter is the
message, the second is the identifier for the dialog, the third
is a flag that says which is the type of the message(it has two
possible values - B2B_REQUEST and B2B_REPLY). The last
parameter is the parameter by the upper module when the entity
was created.
2.3. client_new
Field type:
...
typedef str* (*b2b_client_new_t) (client_info_t* , b2b_notify_t b2b_cbac
k,
b2b_add_dlginfo_t add_dlginfo_f, str* param);
...
This function asks the b2b_entities modules to create a new
client entity record and also create a new dialog by sending an
initial message. The parameters are all the values needed for
the initial request to which the notify function and parameter
are added. The b2b_cback parameter is a pointer to the callback
that must be called when an event happens(receiving a reply or
request) in the dialog created with this function. The
add_dlginfo_f parameter is also a function pointer to a
callback that will be called when a final success response will
be received for the created dialog. The callback will receive
as parameter the complete dialog information for the record. It
should be stored and used when calling send_request or
send_reply functions.
The return value is an identifier for the record that will be
mentioned when calling other functions that represent actions
in the dialog(send request, send reply).
2.4. send_request
Field type:
...
typedef int (*b2b_send_request_t)(enum b2b_entity_type ,str* b2b_key, st
r* method,
str* extra_headers, str* body, b2b_dlginfo_t*);
...
This function asks the b2b_entities modules to send a request
inside a b2b dialog identified by b2b_key. The first parameter
is the entity type and can have two values: B2B_SERVER and
B2B_CLIENT. The second is the identifier returned by the create
function(server_new or client_new) and the next are the
informations needed for the new request: method, extra_headers,
body. The last parameter contains the dialog information -
callid, to tag, from tag. These are needed to make a perfect
match to of b2b_entities record for which a new request must be
sent.
The return value is 0 for success and a negative value for
error.
2.5. send_reply
Field type:
...
typedef int (*b2b_send_reply_t)(enum b2b_entity_type et, str* b2b_key, i
nt code, str* text,
str* body, str* extra_headers, b2b_dlginfo_t* dlginfo);
...
This function asks the b2b_entities modules to send a reply
inside a b2b dialog identified by b2b_key. The first parameter
is the entity type and can have two values: B2B_SERVER and
B2B_CLIENT. The second is the identifier returned by the create
function(server_new or client_new) and the next are the
informations needed for the new reply: code, text, body,
extra_headers. The last parameter contains the dialog
information used for matching the right record.
The return value is 0 for success and a negative value for
error.
2.6. entity_delete
Field type:
...
typedef void (*b2b_entity_delete_t)(enum b2b_entity_type et, str* b2b_ke
y,
b2b_dlginfo_t* dlginfo);
...
This function must be called by the upper level function to
delete the records in b2b_entities. The records are not cleaned
up by the b2b_entities module and the upper level module must
take care to delete them.
2.7. restore_logic_info
Field type:
...
typedef int (*b2b_restore_linfo_t)(enum b2b_entity_type type, str* key,
b2b_notify_t cback);
...
This function is used at startup when loading the data from the
database to restore the pointer to the callback function.
2.8. update_b2bl_param
Field type:
...
typedef int (*b2b_update_b2bl_param_t)(enum b2b_entity_type type, str* k
ey,
str* param);
...
This function can be used to change the logic param stored for
an entity ( useful in case an entity is moved between logic
records).
