HP-UX C SIP Stack Programmer's Guide (Novembery 2007)

Working with Register-Clients 135

new state. For example, upon receipt of an UNAUTHENTICATED state

notification, your application can use the RvSipRegClientAuthenticate() to re-

send the registration request with authentication information.

RvSipRegClientMsgToSendEv()

The register-client calls this event whenever a register-client related message is

ready to be sent. You can use this callback for changing or examining a message

before it is sent.

RvSipRegClientMsgReceivedEv()

The register-client calls this event whenever a register-client related message

has been received and is about to be processed. You can use this callback to

examine incoming messages.

RvSipRegClientFinalDestResolvedEv()

Indicates that the register-client is about to send a message after the destination

address was resolved. This callback supplies the final message and the

transaction that is responsible for sending this message. Changes in the message

at this stage will not effect the destination address. When this callback is called,

the application can query the transaction about the destination address using the

RvSipTransactionGetCurrentDestAddress() function. If the application wishes,

it can update the sent-by part of the top-most Via header. The application must

not update the branch parameter.

Note To change the destination address resolved from the message, the

application must use the Transmitter API. The application should first get the

transmitter from the transaction using the RvSipTransactionGetTransmitter() API

function. In can then manipulate the DNS list current destination address of the

transmitter before the message is sent.

TATE MACHINE

The Register-Client state machine represents the state of the registration

process. The RvSipRegClientStateChangedEv() callback reports register-client

state changes and state change reasons. The state change reason indicates how

the register-client reached the new state. Some of the register-client states are

basic and common to most registration scenarios. Advanced register-client

states depend on SIP Stack configuration.

The register-client associates with the basic states described below.