1 .\" Copyright (c) 1983, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 3. All advertising materials mentioning features or use of this software
13 .\" must display the following acknowledgement:
14 .\" This product includes software developed by the University of
15 .\" California, Berkeley and its contributors.
16 .\" 4. Neither the name of the University nor the names of its contributors
17 .\" may be used to endorse or promote products derived from this software
18 .\" without specific prior written permission.
20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 .Nd send a message from an SCTP socket
48 .Fn sctp_recvmsg "int s" "void *msg" "size_t len" "struct sockaddr * restrict from" "socklen_t * restrict fromlen" "struct sctp_sndrcvinfo *sinfo" "int *flags"
53 is used to receive a message from another SCTP endpoint.
56 call is used by one-to-one (SOCK_STREAM) type sockets after a
59 call or after the application has performed a
61 followed by a sucessful
63 For a one-to-many (SOCK_SEQPACKET)type socket, an endpoint may call
65 after having implicitly started an association via one
66 of the send calls including
71 Or, an application may also receive a message after having
74 with a postive backlog to enable the reception of new associations.
77 The address of the sender is held in the
81 specifying its size. At the completion of a sucessful
85 will hold the address of the peer and
87 will hold the length of that address. Note that
88 the address is bounded by the inital value of
90 which is used as an in/out variable.
92 The length of the message
94 to be received is bounded by
96 If the message is to long to fit in the users
97 receive buffer, then the
99 argument will NOT have the MSG_EOF flag
100 applied. If the message is a complete message then
103 argument will have MSG_EOF set. Locally detected errors are
104 indicated by a return value of -1 with errno set accordingly.
107 argument may also hold the value MSG_NOTIFICATION. When this
108 occurs this indicates that the message received is NOT from
109 the peer endpoint, but instead is a notification from the
112 for more details). Note that no notifications are ever
113 given unless the user subscribes to such notifications using
114 the SCTP_EVENTS socket option.
116 If no messages is available at the socket then
118 normally blocks on the reception of a message or NOTIFICATION, unless the socket has been placed in
119 non-blocking I/O mode.
122 system call may be used to determine when it is possible to
128 argument is defined as follows.
130 struct sctp_sndrcvinfo {
131 u_int16_t sinfo_stream; /* Stream arriving on */
132 u_int16_t sinfo_ssn; /* Stream Sequence Number */
133 u_int16_t sinfo_flags; /* Flags on the incoming message */
134 u_int32_t sinfo_ppid; /* The ppid field */
135 u_int32_t sinfo_context; /* context field */
136 u_int32_t sinfo_timetolive; /* not used by sctp_recvmsg */
137 u_int32_t sinfo_tsn; /* The transport sequence number */
138 u_int32_t sinfo_cumtsn; /* The cumulative acknowledgment point */
139 sctp_assoc_t sinfo_assoc_id; /* The association id of the peer */
144 .Fa sinfo->sinfo_ppid
145 is an opaque 32 bit value that is passed transparently
146 through the stack from the peer endpoint.
147 Note that the stack passes this value without regard to byte
151 .Fa sinfo->sinfo_flags
152 field may include the following:
154 #define SCTP_UNORDERED 0x0400 /* Message is un-ordered */
159 flag is used to specify that the message arrived with no
160 specific order and was delivered to the peer application
161 as soon as possible. When this flag is absent the message
162 was delivered in order within the stream it was received.
164 .Fa sinfo->sinfo_stream
165 is the SCTP stream that the message was received on.
166 Streams in SCTP are reliable (or partially reliable) flows of ordered
170 .Fa sinfo->sinfo_context
171 field is used only if the local application set a association level
172 context with the SCTP_CONTEXT socket option.
173 Optionally a user process can use this value to index some application
174 specific data structure for all data coming from a specific
179 will hold the stream sequence number assigned
180 by the peer endpoint if the message is NOT unordered.
181 For unordered messages this field holds an undefined value.
185 holds a transport sequence number (TSN) that was assigned
186 to this message by the peer endpoint. For messages that fit in or less
187 than the path MTU this will be the only TSN assigned.
188 Note that for messages that span multiple TSN's this
189 value will be one of the TSN's that was used on the
193 .Fa sinfo->sinfo_cumtsn
194 holds the current cumulative acknowledgment point of
195 the transport association. Note that this may be larger
196 or smaller than the TSN assigned to the message itself.
199 sinfo->sinfo_assoc_id
200 is the unique association identification that was assigned
201 to the association. For one-to-many (SOCK_SEQPACKET) type
202 sockets this value can be used to send data to the peer without
203 the use of an address field. It is also quite useful in
204 setting various socket options on the specific association
210 sinfo->info_timetolive
214 The call returns the number of characters sent, or -1
215 if an error occurred.
223 An invalid descriptor was specified.
229 An invalid user space address was specified for an argument.
231 The socket requires that message be sent atomically,
232 and the size of the message to be sent made this impossible.
234 The socket is marked non-blocking and the requested operation
237 The system was unable to allocate an internal buffer.
238 The operation may succeed when buffers become available.
240 The output queue for a network interface was full.
241 This generally indicates that the interface has stopped sending,
242 but may be caused by transient congestion.
243 .It Bq Er EHOSTUNREACH
244 The remote host was unreachable.
246 On a one to one style socket no association exists.
248 An abort was received by the stack while the user was
249 attempting to send data to the peer.
251 On a one to many style socket no address is specified
252 so that the association cannot be located or the
253 SCTP_ABORT flag was specified on a non-existing association.
255 The socket is unable to send anymore data
256 .Dv ( SBS_CANTSENDMORE
257 has been set on the socket).
258 This typically means that the socket
259 is not connected and is a one-to-one style socket.