Group PJSIP_TRANSACT_TRANSACTION¶

group PJSIP_TRANSACT_TRANSACTION

Transaction instance for all types of SIP transactions.

The pjsip_transaction describes SIP transaction, and is used for both INVITE and non-INVITE, UAC or UAS. Application must register the transaction layer module with pjsip_tsx_layer_init_module() before performing any stateful operations.

Enums

enum pjsip_tsx_state_e¶

This enumeration represents transaction state.

Values:

enumerator PJSIP_TSX_STATE_NULL¶: For UAC, before any message is sent.

enumerator PJSIP_TSX_STATE_CALLING¶: For UAC, just after request is sent.

enumerator PJSIP_TSX_STATE_TRYING¶: For UAS, just after request is received.

enumerator PJSIP_TSX_STATE_PROCEEDING¶: For UAS/UAC, after provisional response.

enumerator PJSIP_TSX_STATE_COMPLETED¶: For UAS/UAC, after final response.

enumerator PJSIP_TSX_STATE_CONFIRMED¶: For UAS, after ACK is received.

enumerator PJSIP_TSX_STATE_TERMINATED¶: For UAS/UAC, before it’s destroyed.

enumerator PJSIP_TSX_STATE_DESTROYED¶: For UAS/UAC, will be destroyed now.

enumerator PJSIP_TSX_STATE_MAX¶: Number of states.

Functions

pj_status_t pjsip_tsx_layer_init_module(pjsip_endpoint *endpt)¶

Create and register transaction layer module to the specified endpoint.

Parameters: endpt – The endpoint instance.
Returns: PJ_SUCCESS on success.

pjsip_module *pjsip_tsx_layer_instance(void)¶

Get the instance of the transaction layer module.

Returns: The transaction layer module.

pj_status_t pjsip_tsx_layer_destroy(void)¶

Unregister and destroy transaction layer module.

Returns: PJ_SUCCESS on success.

unsigned pjsip_tsx_layer_get_tsx_count(void)¶

Retrieve the current number of transactions currently registered in the hash table.

Returns: Number of transactions.

pjsip_transaction *pjsip_tsx_layer_find_tsx(const pj_str_t *key, pj_bool_t lock)¶

Find a transaction with the specified key. The transaction key normally is created by calling pjsip_tsx_create_key() from an incoming message.

Parameters

key – The key string to find the transaction.
lock – If non-zero, transaction will be locked before the function returns, to make sure that it’s not deleted by other threads.

Returns

The matching transaction instance, or NULL if transaction can not be found.

pj_status_t pjsip_tsx_create_uac(pjsip_module *tsx_user, pjsip_tx_data *tdata, pjsip_transaction **p_tsx)¶

Create, initialize, and register a new transaction as UAC from the specified transmit data (tdata). The transmit data must have a valid Request-Line and CSeq header.

If Via header does not exist, it will be created along with a unique branch parameter. If it exists and contains branch parameter, then the branch parameter will be used as is as the transaction key. If it exists but branch parameter doesn’t exist, a unique branch parameter will be created.

Parameters

tsx_user – Module to be registered as transaction user of the new transaction, which will receive notification from the transaction via on_tsx_state() callback.
tdata – The outgoing request message.
p_tsx – On return will contain the new transaction instance.

Returns

PJ_SUCCESS if successfull.

pj_status_t pjsip_tsx_create_uas(pjsip_module *tsx_user, pjsip_rx_data *rdata, pjsip_transaction **p_tsx)¶

Create, initialize, and register a new transaction as UAS from the specified incoming request in rdata. After calling this function, application MUST call pjsip_tsx_recv_msg() so that transaction moves from state NULL.

Parameters

tsx_user – Module to be registered as transaction user of the new transaction, which will receive notification from the transaction via on_tsx_state() callback.
rdata – The received incoming request.
p_tsx – On return will contain the new transaction instance.

Returns

PJ_SUCCESS if successfull.

pj_status_t pjsip_tsx_set_transport(pjsip_transaction *tsx, const pjsip_tpselector *sel)¶

Lock/bind transaction to a specific transport/listener. This is optional, as normally transport will be selected automatically based on the destination of the message upon resolver completion.

Parameters

tsx – The transaction.
sel – Transport selector containing the specification of transport or listener to be used by this transaction to send requests.

Returns

PJ_SUCCESS on success, or the appropriate error code.

void pjsip_tsx_recv_msg(pjsip_transaction *tsx, pjsip_rx_data *rdata)¶

Call this function to manually feed a message to the transaction. For UAS transaction, application MUST call this function after UAS transaction has been created.

This function SHOULD only be called to pass initial request message to UAS transaction. Before this function returns, on_tsx_state() callback of the transaction user will be called. If response message is passed to this function, then on_rx_response() will also be called before on_tsx_state().

Parameters

tsx – The transaction.
rdata – The message.

pj_status_t pjsip_tsx_send_msg(pjsip_transaction *tsx, pjsip_tx_data *tdata)¶

Transmit message in tdata with this transaction. It is possible to pass NULL in tdata for UAC transaction, which in this case the last message transmitted, or the request message which was specified when calling pjsip_tsx_create_uac(), will be sent.

This function decrements the reference counter of the transmit buffer only when it returns PJ_SUCCESS;

Parameters

tsx – The transaction.
tdata – The outgoing message. If NULL is specified, then the last message transmitted (or the message specified in UAC initialization) will be sent.

Returns

PJ_SUCCESS if successfull.

pj_status_t pjsip_tsx_retransmit_no_state(pjsip_transaction *tsx, pjsip_tx_data *tdata)¶

Manually retransmit the last message transmitted by this transaction, without updating the transaction state. This function is useful when TU wants to maintain the retransmision by itself (for example, retransmitting reliable provisional response).

Parameters

tsx – The transaction.
tdata – The outgoing message. If NULL is specified, then the last message transmitted (or the message specified in UAC initialization) will be sent.

Returns

PJ_SUCCESS if successful.

pj_status_t pjsip_tsx_create_key(pj_pool_t *pool, pj_str_t *key, pjsip_role_e role, const pjsip_method *method, const pjsip_rx_data *rdata)¶

Create transaction key, which is used to match incoming requests or response (retransmissions) against transactions.

Parameters

pool – The pool
key – Output key.
role – The role of the transaction.
method – The method to be put as a key.
rdata – The received data to calculate.

Returns

PJ_SUCCESS or the appropriate error code.

pj_status_t pjsip_tsx_terminate(pjsip_transaction *tsx, int code)¶

Force terminate transaction.

Parameters

tsx – The transaction.
code – The status code to report.

pj_status_t pjsip_tsx_stop_retransmit(pjsip_transaction *tsx)¶

Cease retransmission on the UAC transaction. The UAC transaction is still considered running, and it will complete when either final response is received or the transaction times out.

This operation normally is used for INVITE transaction only, when the transaction is cancelled before any provisional response has been received.

Parameters: tsx – The transaction.
Returns: PJ_SUCCESS or the appropriate error code.

pj_status_t pjsip_tsx_set_timeout(pjsip_transaction *tsx, unsigned millisec)¶

Start a timer to terminate transaction after the specified time has elapsed. This function is only valid for INVITE transaction, and only before final response is received for the INVITE transaction. It is normally called after the UAC has sent CANCEL for this INVITE transaction.

The purpose of this function is to terminate the transaction if UAS does not send final response to this INVITE transaction even after it sends 200/OK to CANCEL (for example when the UAS complies to RFC 2543).

Once this timer is set, the transaction will be terminated either when a final response is received or the timer expires.

Parameters

tsx – The transaction.
millisec – Timeout value in milliseconds.

Returns

PJ_SUCCESS or the appropriate error code.

pjsip_transaction *pjsip_rdata_get_tsx(pjsip_rx_data *rdata)¶

Get the transaction instance in the incoming message. If the message has a corresponding transaction, this function will return non NULL value.

Parameters: rdata – The incoming message buffer.
Returns: The transaction instance associated with this message, or NULL if the message doesn’t match any transactions.

struct pjsip_transaction¶

#include <sip_transaction.h>

This structure describes SIP transaction object. The transaction object is used to handle both UAS and UAC transaction.

Forward declaration for transactions (sip_transaction.h).