1t_open(3NSL) Networking Services Library Functions t_open(3NSL)
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6 t_open - establish a transport endpoint
7
9 #include <xti.h>
10 #include <fcntl.h>
11 int t_open(const char *name, int oflag, struct t_info *info);
16
19 This routine is part of the XTI interfaces which evolved from the TLI
20 interfaces. XTI represents the future evolution of these interfaces.
21 However, TLI interfaces are supported for compatibility. When using a
22 TLI routine that has the same name as an XTI routine, the tiuser.h
23 header file must be used. Refer to the TLI COMPATIBILITY section for
24 a description of differences between the two interfaces.
25 The t_open() function must be called as the first step in the initial‐
28 ization of a transport endpoint. This function establishes a transport
29 endpoint by supplying a transport provider identifier that indicates a
30 particular transport provider, that is, transport protocol, and return‐
31 ing a file descriptor that identifies that endpoint.
32 The argument name points to a transport provider identifier and oflag
35 identifies any open flags, as in open(2). The argument oflag is con‐
36 structed from O_RDWR optionally bitwise inclusive-OR'ed with O_NON‐
37 BLOCK. These flags are defined by the header <fcntl.h>. The file
38 descriptor returned by t_open() will be used by all subsequent func‐
39 tions to identify the particular local transport endpoint.
40 This function also returns various default characteristics of the
43 underlying transport protocol by setting fields in the t_info struc‐
44 ture. This argument points to a t_info which contains the following
45 members:
46 t_scalar_t addr; /* max size of the transport protocol address */
48 t_scalar_t options; /* max number of bytes of */
49 /* protocol-specific options */
50 t_scalar_t tsdu; /* max size of a transport service data */
51 /* unit (TSDU) */
52 t_scalar_t etsdu; /* max size of an expedited transport */
53 /* service data unit (ETSDU) */
54 t_scalar_t connect; /* max amount of data allowed on */
55 /* connection establishment functions */
56 t_scalar_t discon; /* max amount of data allowed on */
57 /* t_snddis() and t_rcvdis() functions */
58 t_scalar_t servtype; /* service type supported by the */
59 /* transport provider */
60 t_scalar_t flags; /* other info about the transport provider */
61 The values of the fields have the following meanings:
65 addr A value greater than zero (T_NULL) indicates the maximum
67 size of a transport protocol address and a value of -2
68 (T_INVALID) specifies that the transport provider does not
69 provide user access to transport protocol addresses.
70 options A value greater than zero (T_NULL) indicates the maximum
73 number of bytes of protocol-specific options supported by
74 the provider, and a value of -2 (T_INVALID) specifies that
75 the transport provider does not support user-settable
76 options.
77 tsdu A value greater than zero (T_NULL specifies the maximum
80 size of a transport service data unit (TSDU); a value of
81 zero (T_NULL) specifies that the transport provider does
82 not support the concept of TSDU, although it does support
83 the sending of a data stream with no logical boundaries
84 preserved across a connection; a value of -1 (T_INFINITE)
85 specifies that there is no limit to the size of a TSDU; and
86 a value of -2 (T_INVALID) specifies that the transfer of
87 normal data is not supported by the transport provider.
88 etsdu A value greater than zero (T_NULL) specifies the maximum
91 size of an expedited transport service data unit (ETSDU); a
92 value of zero (T_NULL) specifies that the transport
93 provider does not support the concept of ETSDU, although it
94 does support the sending of an expedited data stream with
95 no logical boundaries preserved across a connection; a
96 value of -1 (T_INFINITE) specifies that there is no limit
97 on the size of an ETSDU; and a value of -2 (T_INVALID)
98 specifies that the transfer of expedited data is not sup‐
99 ported by the transport provider. Note that the semantics
100 of expedited data may be quite different for different
101 transport providers.
102 connect A value greater than zero (T_NULL) specifies the maximum
105 amount of data that may be associated with connection
106 establishment functions, and a value of -2 (T_INVALID)
107 specifies that the transport provider does not allow data
108 to be sent with connection establishment functions.
109 discon If the T_ORDRELDATA bit in flags is clear, a value greater
112 than zero (T_NULL) specifies the maximum amount of data
113 that may be associated with the t_snddis(3NSL) and
114 t_rcvdis(3NSL) functions, and a value of -2 (T_INVALID)
115 specifies that the transport provider does not allow data
116 to be sent with the abortive release functions. If the
117 T_ORDRELDATA bit is set in flags, a value greater than zero
118 (T_NULL) specifies the maximum number of octets that may be
119 associated with the t_sndreldata(), t_rcvreldata(), t_snd‐
120 dis(3NSL) and t_rcvdis(3NSL) functions.
121 servtype This field specifies the service type supported by the
124 transport provider, as described below.
125 flags This is a bit field used to specify other information about
128 the communications provider. If the T_ORDRELDATA bit is
129 set, the communications provider supports user data to be
130 sent with an orderly release. If the T_SENDZERO bit is set
131 in flags, this indicates the underlying transport provider
132 supports the sending of zero-length TSDUs.
133 If a transport user is concerned with protocol independence, the above
137 sizes may be accessed to determine how large the buffers must be to
138 hold each piece of information. Alternatively, the t_alloc(3NSL) func‐
139 tion may be used to allocate these buffers. An error will result if a
140 transport user exceeds the allowed data size on any function.
141 The servtype field of info specifies one of the following values on
144 return:
145 T_COTS The transport provider supports a connection-mode ser‐
147 vice but does not support the optional orderly release
148 facility.
149 T_COTS_ORD The transport provider supports a connection-mode ser‐
152 vice with the optional orderly release facility.
153 T_CLTS The transport provider supports a connectionless-mode
156 service. For this service type, t_open() will return -2
157 (T_INVALID) for etsdu, connect and discon.
158 A single transport endpoint may support only one of the above services
162 at one time.
163 If info is set to a null pointer by the transport user, no protocol
166 information is returned by t_open().
167
169 A valid file descriptor is returned upon successful completion. Other‐
170 wise, a value of -1 is returned and t_errno is set to indicate an
171 error.
172
174 T_UNINIT.
175
177 On failure, t_errno is set to the following:
178 TBADFLAG An invalid flag is specified.
180 TBADNAME Invalid transport provider name.
183 TPROTO This error indicates that a communication problem has been
186 detected between XTI and the transport provider for which
187 there is no other suitable XTI error (t_errno).
188 TSYSERR A system error has occurred during execution of this func‐
191 tion.
192
195 The XTI and TLI interface definitions have common names but use differ‐
196 ent header files. This and other semantic differences between the two
197 interfaces are described in the subsections below.
198 Interface Header
200 The XTI interfaces use the xti.h TLI interfaces should not use this
201 header. They should use the header:
202 #include <tiuser.h>
203 Error Description Values
205 The t_errno values TPROTO and TBADNAME can be set by the XTI interface
206 but cannot be set by the TLI interface.
207 Notes
209 For TLI , the t_info structure referenced by info lacks the following
210 structure member:
211 t_scalar_t flags; /* other info about the transport provider */
213 This member was added to struct t_info in the XTI interfaces.
217 When a value of -1 is observed as the return value in various t_info
220 structure members, it signifies that the transport provider can handle
221 an infinite length buffer for a corresponding attribute, such as
222 address data, option data, TSDU (octet size), ETSDU (octet size), con‐
223 nection data, and disconnection data. The corresponding structure mem‐
224 bers are addr, options, tsdu, estdu, connect, and discon, respectively.
225
227 See attributes(5) for descriptions of the following attributes:
228 ┌─────────────────────────────┬─────────────────────────────┐
233 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
234 ├─────────────────────────────┼─────────────────────────────┤
235 │MT Level │Safe │
236 └─────────────────────────────┴─────────────────────────────┘
237
239 open(2), attributes(5)
240SunOS 5.11 7 May 1998 t_open(3NSL)