State Transitions

The tables in the following sections describe all state transitions associated with XTI/TLI.

XTI/TLI States

The following table defines the states used in XTI/TLI state transitions, along with the service types.

Table 9–1 XTI/TLI State Transitions and Service Types

State	Description	Service Type
T_UNINIT	Uninitialized–initial and final state of interface	T_COTS, T_COTS_ORD, T_CLTS
T_UNBND	Initialized but not bound	T_COTS, T_COTS_ORD, T_CLTS
T_IDLE	No connection established	T_COTS, T_COTS_ORD, T_CLTS
T_OUTCON	Outgoing connection pending for client	T_COTS, T_COTS_ORD
T_INCON	Incoming connection pending for server	T_COTS, T_COTS_ORD
T_DATAXFER	Data transfer	T_COTS, T_COTS_ORD
T_OUTREL	Outgoing orderly release (waiting for orderly release request)	T_COTS_ORD
T_INREL	Incoming orderly release (waiting to send orderly release request)	T_COTS_ORD

Outgoing Events

The outgoing events described in the following table correspond to the status returned from the specified transport routines, where these routines send a request or response to the transport provider. In the table, some events, such as “accept,” are distinguished by the context in which they occur. The context is based on the values of the following variables:

• ocnt – Count of outstanding connect requests

• fd – File descriptor of the current transport endpoint

• resfd – File descriptor of the transport endpoint where a connection is accepted

Table 9–2 Outgoing Events

Event	Description	Service Type
opened	Successful return of t_open(3NSL)	T_COTS, T_COTS_ORD, T_CLTS
bind	Successful return of t_bind(3NSL)	T_COTS, T_COTS_ORD, T_CLTS
optmgmt	Successful return of t_optmgmt(3NSL)	T_COTS, T_COTS_ORD, T_CLTS
unbind	Successful return of t_unbind(3NSL)	T_COTS, T_COTS_ORD, T_CLTS
closed	Successful return of t_close(3NSL)	T_COTS, T_COTS_ORD, T_CLT
connect1	Successful return of t_connect(3NSL) in synchronous mode	T_COTS, T_COTS_ORD
connect2	TNODATA error on t_connect(3NSL) in asynchronous mode, or TLOOK error due to a disconnect request arriving on the transport endpoint	T_COTS, T_COTS_ORD
accept1	Successful return of t_accept(3NSL) with ocnt == 1, fd == resfd	T_COTS, T_COTS_ORD
accept2	Successful return of t_accept(3NSL) with ocnt== 1, fd!= resfd	T_COTS, T_COTS_ORD
accept3	Successful return of t_accept(3NSL) with ocnt > 1	T_COTS, T_COTS_ORD
snd	Successful return of t_snd(3NSL)	T_COTS, T_COTS_ORD
snddis1	Successful return of t_snddis(3NSL) with ocnt <= 1	T_COTS, T_COTS_ORD
snddis2	Successful return of t_snddis(3NSL) with ocnt > 1	T_COTS, T_COTS_ORD
sndrel	Successful return of t_sndrel(3NSL)	T_COTS_ORD
sndudata	Successful return of t_sndudata(3NSL)	T_CLTS

Incoming Events

The incoming events correspond to the successful return of the specified routines. These routines return data or event information from the transport provider. The only incoming event not associated directly with the return of a routine is pass_conn, which occurs when a connection is transferred to another endpoint. The event occurs on the endpoint that is being passed the connection, although no XTI/TLI routine is called on the endpoint.

In the following table, the rcvdis events are distinguished by the value of ocnt, the count of outstanding connect requests on the endpoint.

Table 9–3 Incoming Events

Event	Description	Service Type
listen	Successful return of t_listen(3NSL)	T_COTS, T_COTS_ORD
rcvconnect	Successful return of t_rcvconnect(3NSL)	T_COTS, T_COTS_ORD
rcv	Successful return of t_rcv(3NSL)	T_COTS, T_COTS_ORD
rcvdis1	Successful return of t_rcvdis(3NSL) rcvdis1t_rcvdis(), onct <= 0	T_COTS, T_COTS_ORD
rcvdis2	Successful return of t_rcvdis(3NSL), ocnt == 1	T_COTS, T_COTS_ORD
rcvdis3	Successful return of t_rcvdis(3NSL) with ocnt > 1	T_COTS, T_COTS_ORD
rcvrel	Successful return of t_rcvrel(3NSL)	T_COTS_ORD
rcvudata	Successful return of t_rcvudata(3NSL)	T_CLTS
rcvuderr	Successful return of t_rcvuderr(3NSL)	T_CLTS
pass_conn	Receive a passed connection	T_COTS, T_COTS_ORD

State Tables

The state tables describe the XTI/TLI state transitions. Each box contains the next state, given the current state (column) and the current event (row). An empty box is an invalid state/event combination. Each box can also have an action list. Actions must be done in the order specified in the box.

You should understand the following when studying the state tables:

• t_close(3NSL) terminates an established connection for a connection-oriented transport provider. The connection termination will be either orderly or abortive, depending on the service type supported by the transport provider. See the t_getinfo(3NSL) man page.

• If a transport user issues a interface call out of sequence, the interface fails and t_errno is set to TOUTSTATE. The state does not change.

• The error codes TLOOK or TNODATA after t_connect(3NSL) can result in state changes. The state tables assume correct use of XTI/TLI.

• Any other transport error does not change the state, unless the man page for the interface says otherwise.

• The support interfaces t_getinfo(3NSL), t_getstate(3NSL), t_alloc(3NSL), t_free(3NSL), t_sync(3NSL), t_look(3NSL), and t_error(3NSL) are excluded from the state tables because they do not affect the state.

Some of the state transitions listed in the tables below offer actions the transport user must take. Each action is represented by a digit derived from the list below:

• Set the count of outstanding connect requests to zero

• Increment the count of outstanding connect requests

• Decrement the count of outstanding connect requests

• Pass a connection to another transport endpoint, as indicated in thet_accept(3NSL) man page

The following table shows endpoint establishment states.

Table 9–4 Connection Establishment State

Event/State	T_UNINIT	T_UNBND	T_IDLE
opened	T_UNBND
bind		T_IDLE[1]
optmgmt (TLI only)			T_IDLE
unbind			T_UNBND
closed		T_UNINIT

The following table shows data transfer in connection mode.

Table 9–5 Connection Mode State: Part 1

Event/State	T_IDLE	T_OUTCON	T_INCON	T_DATAXFER
connect1	T_DATAXFER
connect2	T_OUTCON
rcvconnect		T_DATAXFER
listen	T_INCON [2]		T_INCON [2]
accept1			T_DATAXFER [3]
accept2			T_IDLE [3] [4]
accept3			T_INCON [3] [4]
snd				T_DATAXFER
rcv				T_DATAXFER
snddis1		T_IDLE	T_IDLE [3]	T_IDLE
snddis2			T_INCON [3]
rcvdis1		T_IDLE		T_IDLE
rcvdis2			T_IDLE [3]
rcvdis3			T_INCON [3]
sndrel				T_OUTREL
rcvrel				T_INREL
pass_conn	T_DATAXFER
optmgmt	T_IDLE	T_OUTCON	T_INCON	T_DATAXFER
closed	T_UNINIT	T_UNINIT	T_UNINIT	T_UNINIT

The following table shows connection establishment/connection release/data transfer in connection mode.

Table 9–6 Connection Mode State: Part 2

Event/State	T_OUTREL	T_INREL	T_UNBND
connect1
connect2
rcvconnect
listen
accept1
accept2
accept3
snd		T_INREL
rcv	T_OUTREL
snddis1	T_IDLE	T_IDLE
snddis2
rcvdis1	T_IDLE	T_IDLE
rcvdis2
rcvdis3
sndrel		T_IDLE
rcvrel	T_IDLE
pass_conn			T_DATAXFER
optmgmt	T_OUTREL	T_INREL	T_UNBND
closed	T_UNINIT	T_UNINIT

The following table shows connectionless mode states.

Table 9–7 Connectionless Mode State

Event/State	T_IDLE
snudata	T_IDLE
rcvdata	T_IDLE
rcvuderr	T_IDLE