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:

PJSIP_TSX_STATE_NULL

For UAC, before any message is sent.

PJSIP_TSX_STATE_CALLING

For UAC, just after request is sent.

PJSIP_TSX_STATE_TRYING

For UAS, just after request is received.

PJSIP_TSX_STATE_PROCEEDING

For UAS/UAC, after provisional response.

PJSIP_TSX_STATE_COMPLETED

For UAS/UAC, after final response.

PJSIP_TSX_STATE_CONFIRMED

For UAS, after ACK is received.

PJSIP_TSX_STATE_TERMINATED

For UAS/UAC, before it’s destroyed.

PJSIP_TSX_STATE_DESTROYED

For UAS/UAC, will be destroyed now.

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.

Return

PJ_SUCCESS on success.

Parameters
  • endpt: The endpoint instance.

pjsip_module *pjsip_tsx_layer_instance(void)

Get the instance of the transaction layer module.

Return

The transaction layer module.

pj_status_t pjsip_tsx_layer_destroy(void)

Unregister and destroy transaction layer module.

Return

PJ_SUCCESS on success.

unsigned pjsip_tsx_layer_get_tsx_count(void)

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

Return

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.

IMPORTANT: To prevent deadlock, application should use pjsip_tsx_layer_find_tsx2() instead which only adds a reference to the transaction instead of locking it.

Return

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

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.

pjsip_transaction *pjsip_tsx_layer_find_tsx2(const pj_str_t *key, pj_bool_t add_ref)

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

Return

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

Parameters
  • key: The key string to find the transaction.

  • add_ref: If non-zero, transaction’s reference will be added by one before the function returns, to make sure that it’s not deleted by other threads.

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.

Return

PJ_SUCCESS if successfull.

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.

pj_status_t pjsip_tsx_create_uac2(pjsip_module *tsx_user, pjsip_tx_data *tdata, pj_grp_lock_t *grp_lock, pjsip_transaction **p_tsx)

Variant of pjsip_tsx_create_uac() with additional parameter to specify the group lock to use. Group lock can be used to synchronize locking among several objects to prevent deadlock, and to synchronize the lifetime of objects sharing the same group lock.

See pjsip_tsx_create_uac() for general info about this function.

Return

PJ_SUCCESS if successfull.

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.

  • grp_lock: Optional group lock to use by this transaction. If the value is NULL, the transaction will create its own group lock.

  • p_tsx: On return will contain the new transaction instance.

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.

Return

PJ_SUCCESS if successfull.

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.

pj_status_t pjsip_tsx_create_uas2(pjsip_module *tsx_user, pjsip_rx_data *rdata, pj_grp_lock_t *grp_lock, pjsip_transaction **p_tsx)

Variant of pjsip_tsx_create_uas() with additional parameter to specify the group lock to use. Group lock can be used to synchronize locking among several objects to prevent deadlock, and to synchronize the lifetime of objects sharing the same group lock.

See pjsip_tsx_create_uas() for general info about this function.

Return

PJ_SUCCESS if successfull.

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.

  • grp_lock: Optional group lock to use by this transaction. If the value is NULL, the transaction will create its own group lock.

  • p_tsx: On return will contain the new transaction instance.

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.

Return

PJ_SUCCESS on success, or the appropriate error code.

Parameters
  • tsx: The transaction.

  • sel: Transport selector containing the specification of transport or listener to be used by this transaction to send requests.

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;

Return

PJ_SUCCESS if successfull.

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.

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).

Return

PJ_SUCCESS if successful.

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.

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.

Return

PJ_SUCCESS or the appropriate error code.

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.

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.

Return

PJ_SUCCESS or the appropriate error code.

Parameters
  • tsx: The transaction.

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.

Return

PJ_SUCCESS or the appropriate error code.

Parameters
  • tsx: The transaction.

  • millisec: Timeout value in milliseconds.

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.

Return

The transaction instance associated with this message, or NULL if the message doesn’t match any transactions.

Parameters
  • rdata: The incoming message buffer.

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).