1t_connect(3NSL) Networking Services Library Functions t_connect(3NSL)
2
6 t_connect - establish a connection with another transport user
7
9 #include <xti.h>
10 int t_connect(int fd, const struct t_call *sndcall,
12 struct t_call *rcvcall);
13
16 This routine is part of the XTI interfaces which evolved from the TLI
17 interfaces. XTI represents the future evolution of these interfaces.
18 However, TLI interfaces are supported for compatibility. When using a
19 TLI routine that has the same name as an XTI routine, the tiuser.h
20 header file must be used. Refer to the TLI COMPATIBILITY section for
21 a description of differences between the two interfaces. This function
22 enables a transport user to request a connection to the specified des‐
23 tination transport user.
24 This function can only be issued in the T_IDLE state. The parameter fd
27 identifies the local transport endpoint where communication will be
28 established, while sndcall and rcvcall point to a t_call structure
29 which contains the following members:
30 struct netbuf addr;
32 struct netbuf opt;
33 struct netbuf udata;
34 int sequence;
35 The parameter sndcall specifies information needed by the transport
39 provider to establish a connection and rcvcall specifies information
40 that is associated with the newly established connection.
41 In sndcall, addr specifies the protocol address of the destination
44 transport user, opt presents any protocol-specific information that
45 might be needed by the transport provider, udata points to optional
46 user data that may be passed to the destination transport user during
47 connection establishment, and sequence has no meaning for this func‐
48 tion.
49 On return, in rcvcall, addr contains the protocol address associated
52 with the responding transport endpoint, opt represents any protocol-
53 specific information associated with the connection, udata points to
54 optional user data that may be returned by the destination transport
55 user during connection establishment, and sequence has no meaning for
56 this function.
57 The opt argument permits users to define the options that may be passed
60 to the transport provider. The user may choose not to negotiate proto‐
61 col options by setting the len field of opt to zero. In this case, the
62 provider uses the option values currently set for the communications
63 endpoint.
64 If used, sndcall→opt.buf must point to a buffer with the corresponding
67 options, and sndcall→opt.len must specify its length. The maxlen and
68 buf fields of the netbuf structure pointed by rcvcall→addr and rcv‐
69 call→opt must be set before the call.
70 The udata argument enables the caller to pass user data to the destina‐
73 tion transport user and receive user data from the destination user
74 during connection establishment. However, the amount of user data must
75 not exceed the limits supported by the transport provider as returned
76 in the connect field of the info argument of t_open(3NSL) or t_get‐
77 info(3NSL). If the len of udata is zero in sndcall, no data will be
78 sent to the destination transport user.
79 On return, the addr, opt and udata fields of rcvcall will be updated to
82 reflect values associated with the connection. Thus, the maxlen field
83 of each argument must be set before issuing this function to indicate
84 the maximum size of the buffer for each. However, maxlen can be set to
85 zero, in which case no information to this specific argument is given
86 to the user on the return from t_connect(). If maxlen is greater than
87 zero and less than the length of the value, t_connect() fails with
88 t_errno set to TBUFOVFLW. If rcvcall is set to NULL, no information
89 at all is returned.
90 By default, t_connect() executes in synchronous mode, and will wait for
93 the destination user's response before returning control to the local
94 user. A successful return (that is, return value of zero) indicates
95 that the requested connection has been established. However, if O_NON‐
96 BLOCK is set by means of t_open(3NSL) or fcntl(2), t_connect() exe‐
97 cutes in asynchronous mode. In this case, the call will not wait for
98 the remote user's response, but will return control immediately to the
99 local user and return -1 with t_errno set to TNODATA to indicate that
100 the connection has not yet been established. In this way, the function
101 simply initiates the connection establishment procedure by sending a
102 connection request to the destination transport user. The t_rcvcon‐
103 nect(3NSL) function is used in conjunction with t_connect() to deter‐
104 mine the status of the requested connection.
105 When a synchronous t_connect() call is interrupted by the arrival of a
108 signal, the state of the corresponding transport endpoint is T_OUTCON,
109 allowing a further call to either t_rcvconnect(3NSL), t_rcvdis(3NSL) or
110 t_snddis(3NSL). When an asynchronous t_connect() call is interrupted
111 by the arrival of a signal, the state of the corresponding transport
112 endpoint is T_IDLE.
113
115 Upon successful completion, a value of 0 is returned. Otherwise, a
116 value of -1 is returned and t_errno is set to indicate an error.
117
119 T_IDLE
120
122 On failure, t_errno is set to one of the following:
123 TACCES The user does not have permission to use the specified
125 address or options.
126 TADDRBUSY This transport provider does not support multiple con‐
129 nections with the same local and remote addresses. This
130 error indicates that a connection already exists.
131 TBADADDR The specified protocol address was in an incorrect for‐
134 mat or contained illegal information.
135 TBADDATA The amount of user data specified was not within the
138 bounds allowed by the transport provider.
139 TBADF The specified file descriptor does not refer to a trans‐
142 port endpoint.
143 TBADOPT The specified protocol options were in an incorrect for‐
146 mat or contained illegal information.
147 TBUFOVFLW The number of bytes allocated for an incoming argument
150 (maxlen) is greater than 0 but not sufficient to store
151 the value of that argument. If executed in synchronous
152 mode, the provider's state, as seen by the user, changes
153 to T_DATAXFER, and the information to be returned in
154 rcvcall is discarded.
155 TLOOK An asynchronous event has occurred on this transport
158 endpoint and requires immediate attention.
159 TNODATA O_NONBLOCK was set, so the function successfully initi‐
162 ated the connection establishment procedure, but did not
163 wait for a response from the remote user.
164 TNOTSUPPORT This function is not supported by the underlying trans‐
167 port provider.
168 TOUTSTATE The communications endpoint referenced by fd is not in
171 one of the states in which a call to this function is
172 valid.
173 TPROTO This error indicates that a communication problem has
176 been detected between XTI and the transport provider for
177 which there is no other suitable XTI error (t_errno).
178 TSYSERR A system error has occurred during execution of this
181 function.
182
185 The XTI and TLI interface definitions have common names but use differ‐
186 ent header files. This, and other semantic differences between the two
187 interfaces are described in the subsections below.
188 Interface Header
190 The XTI interfaces use the header file, xti.h. TLI interfaces should
191 not use this header. They should use the header:
192 #include <tiuser.h>
194 Error Description Values
197 The TPROTO and TADDRBUSY t_errno values can be set by the XTI interface
198 but not by the TLI interface.
199 A t_errno value that this routine can return under different circum‐
202 stances than its XTI counterpart is TBUFOVFLW. It can be returned even
203 when the maxlen field of the corresponding buffer has been set to zero.
204 Option Buffers
206 The format of the options in an opt buffer is dictated by the transport
207 provider. Unlike the XTI interface, the TLI interface does not fix the
208 buffer format.
209
211 See attributes(5) for descriptions of the following attributes:
212 ┌─────────────────────────────┬─────────────────────────────┐
217 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
218 ├─────────────────────────────┼─────────────────────────────┤
219 │MT Level │Safe │
220 └─────────────────────────────┴─────────────────────────────┘
221
223 fcntl(2), t_accept(3NSL), t_alloc(3NSL), t_getinfo(3NSL), t_lis‐
224 ten(3NSL), t_open(3NSL), t_optmgmt(3NSL), t_rcvconnect(3NSL),
225 t_rcvdis(3NSL), t_snddis(3NSL), attributes
226SunOS 5.11 7 May 1998 t_connect(3NSL)