Merge branch 'vendor/OPENSSL'
[dragonfly.git] / secure / lib / libcrypto / man / BIO_s_accept.3
CommitLineData
aac4ff6f 1.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32
8b0cefbb
JR
2.\"
3.\" Standard preamble:
4.\" ========================================================================
5.de Sh \" Subsection heading
984263bc
MD
6.br
7.if t .Sp
8.ne 5
9.PP
10\fB\\$1\fR
11.PP
12..
8b0cefbb 13.de Sp \" Vertical space (when we can't use .PP)
984263bc
MD
14.if t .sp .5v
15.if n .sp
16..
8b0cefbb 17.de Vb \" Begin verbatim text
984263bc
MD
18.ft CW
19.nf
20.ne \\$1
21..
8b0cefbb 22.de Ve \" End verbatim text
984263bc 23.ft R
984263bc
MD
24.fi
25..
8b0cefbb
JR
26.\" Set up some character translations and predefined strings. \*(-- will
27.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
aac4ff6f
PA
28.\" double quote, and \*(R" will give a right double quote. | will give a
29.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used to
30.\" do unbreakable dashes and therefore won't be available. \*(C` and \*(C'
31.\" expand to `' in nroff, nothing in troff, for use with C<>.
32.tr \(*W-|\(bv\*(Tr
8b0cefbb 33.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
984263bc 34.ie n \{\
8b0cefbb
JR
35. ds -- \(*W-
36. ds PI pi
37. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
38. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
39. ds L" ""
40. ds R" ""
41. ds C` ""
42. ds C' ""
984263bc
MD
43'br\}
44.el\{\
8b0cefbb
JR
45. ds -- \|\(em\|
46. ds PI \(*p
47. ds L" ``
48. ds R" ''
984263bc 49'br\}
8b0cefbb
JR
50.\"
51.\" If the F register is turned on, we'll generate index entries on stderr for
52.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
53.\" entries marked with X<> in POD. Of course, you'll have to process the
54.\" output yourself in some meaningful fashion.
55.if \nF \{\
56. de IX
57. tm Index:\\$1\t\\n%\t"\\$2"
984263bc 58..
8b0cefbb
JR
59. nr % 0
60. rr F
984263bc 61.\}
8b0cefbb 62.\"
aac4ff6f
PA
63.\" For nroff, turn off justification. Always turn off hyphenation; it makes
64.\" way too many mistakes in technical documents.
65.hy 0
66.if n .na
67.\"
8b0cefbb
JR
68.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
69.\" Fear. Run. Save yourself. No user-serviceable parts.
70. \" fudge factors for nroff and troff
984263bc 71.if n \{\
8b0cefbb
JR
72. ds #H 0
73. ds #V .8m
74. ds #F .3m
75. ds #[ \f1
76. ds #] \fP
984263bc
MD
77.\}
78.if t \{\
8b0cefbb
JR
79. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
80. ds #V .6m
81. ds #F 0
82. ds #[ \&
83. ds #] \&
984263bc 84.\}
8b0cefbb 85. \" simple accents for nroff and troff
984263bc 86.if n \{\
8b0cefbb
JR
87. ds ' \&
88. ds ` \&
89. ds ^ \&
90. ds , \&
91. ds ~ ~
92. ds /
984263bc
MD
93.\}
94.if t \{\
8b0cefbb
JR
95. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
96. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
97. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
98. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
99. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
100. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
984263bc 101.\}
8b0cefbb 102. \" troff and (daisy-wheel) nroff accents
984263bc
MD
103.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
104.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
105.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
106.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
107.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
108.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
109.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
110.ds ae a\h'-(\w'a'u*4/10)'e
111.ds Ae A\h'-(\w'A'u*4/10)'E
8b0cefbb 112. \" corrections for vroff
984263bc
MD
113.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
114.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
8b0cefbb 115. \" for low resolution devices (crt and lpr)
984263bc
MD
116.if \n(.H>23 .if \n(.V>19 \
117\{\
8b0cefbb
JR
118. ds : e
119. ds 8 ss
120. ds o a
121. ds d- d\h'-1'\(ga
122. ds D- D\h'-1'\(hy
123. ds th \o'bp'
124. ds Th \o'LP'
125. ds ae ae
126. ds Ae AE
984263bc
MD
127.\}
128.rm #[ #] #H #V #F C
8b0cefbb
JR
129.\" ========================================================================
130.\"
131.IX Title "BIO_s_accept 3"
18ed9402 132.TH BIO_s_accept 3 "2008-09-27" "0.9.8i" "OpenSSL"
984263bc
MD
133.SH "NAME"
134BIO_s_accept, BIO_set_accept_port, BIO_get_accept_port,
135BIO_set_nbio_accept, BIO_set_accept_bios, BIO_set_bind_mode,
74dab6c2 136BIO_get_bind_mode, BIO_do_accept \- accept BIO
984263bc 137.SH "SYNOPSIS"
8b0cefbb 138.IX Header "SYNOPSIS"
984263bc
MD
139.Vb 1
140\& #include <openssl/bio.h>
aac4ff6f
PA
141.Ve
142.PP
143.Vb 1
984263bc 144\& BIO_METHOD *BIO_s_accept(void);
aac4ff6f
PA
145.Ve
146.PP
147.Vb 2
984263bc
MD
148\& long BIO_set_accept_port(BIO *b, char *name);
149\& char *BIO_get_accept_port(BIO *b);
aac4ff6f
PA
150.Ve
151.PP
152.Vb 1
984263bc 153\& BIO *BIO_new_accept(char *host_port);
aac4ff6f
PA
154.Ve
155.PP
156.Vb 2
984263bc
MD
157\& long BIO_set_nbio_accept(BIO *b, int n);
158\& long BIO_set_accept_bios(BIO *b, char *bio);
aac4ff6f
PA
159.Ve
160.PP
161.Vb 2
984263bc
MD
162\& long BIO_set_bind_mode(BIO *b, long mode);
163\& long BIO_get_bind_mode(BIO *b, long dummy);
aac4ff6f
PA
164.Ve
165.PP
166.Vb 3
984263bc
MD
167\& #define BIO_BIND_NORMAL 0
168\& #define BIO_BIND_REUSEADDR_IF_UNUSED 1
169\& #define BIO_BIND_REUSEADDR 2
aac4ff6f
PA
170.Ve
171.PP
172.Vb 1
984263bc
MD
173\& int BIO_do_accept(BIO *b);
174.Ve
175.SH "DESCRIPTION"
8b0cefbb
JR
176.IX Header "DESCRIPTION"
177\&\fIBIO_s_accept()\fR returns the accept \s-1BIO\s0 method. This is a wrapper
178round the platform's \s-1TCP/IP\s0 socket accept routines.
984263bc 179.PP
8b0cefbb
JR
180Using accept BIOs, \s-1TCP/IP\s0 connections can be accepted and data
181transferred using only \s-1BIO\s0 routines. In this way any platform
182specific operations are hidden by the \s-1BIO\s0 abstraction.
984263bc 183.PP
8b0cefbb 184Read and write operations on an accept \s-1BIO\s0 will perform I/O
984263bc 185on the underlying connection. If no connection is established
8b0cefbb 186and the port (see below) is set up properly then the \s-1BIO\s0
984263bc
MD
187waits for an incoming connection.
188.PP
189Accept BIOs support \fIBIO_puts()\fR but not \fIBIO_gets()\fR.
190.PP
8b0cefbb 191If the close flag is set on an accept \s-1BIO\s0 then any active
984263bc 192connection on that chain is shutdown and the socket closed when
8b0cefbb 193the \s-1BIO\s0 is freed.
984263bc 194.PP
8b0cefbb
JR
195Calling \fIBIO_reset()\fR on a accept \s-1BIO\s0 will close any active
196connection and reset the \s-1BIO\s0 into a state where it awaits another
984263bc
MD
197incoming connection.
198.PP
8b0cefbb
JR
199\&\fIBIO_get_fd()\fR and \fIBIO_set_fd()\fR can be called to retrieve or set
200the accept socket. See \fIBIO_s_fd\fR\|(3)
984263bc 201.PP
8b0cefbb 202\&\fIBIO_set_accept_port()\fR uses the string \fBname\fR to set the accept
984263bc
MD
203port. The port is represented as a string of the form \*(L"host:port\*(R",
204where \*(L"host\*(R" is the interface to use and \*(L"port\*(R" is the port.
205Either or both values can be \*(L"*\*(R" which is interpreted as meaning
206any interface or port respectively. \*(L"port\*(R" has the same syntax
207as the port specified in \fIBIO_set_conn_port()\fR for connect BIOs,
208that is it can be a numerical port string or a string to lookup
209using \fIgetservbyname()\fR and a string table.
210.PP
8b0cefbb
JR
211\&\fIBIO_new_accept()\fR combines \fIBIO_new()\fR and \fIBIO_set_accept_port()\fR into
212a single call: that is it creates a new accept \s-1BIO\s0 with port
213\&\fBhost_port\fR.
984263bc 214.PP
8b0cefbb 215\&\fIBIO_set_nbio_accept()\fR sets the accept socket to blocking mode
984263bc
MD
216(the default) if \fBn\fR is 0 or non blocking mode if \fBn\fR is 1.
217.PP
8b0cefbb 218\&\fIBIO_set_accept_bios()\fR can be used to set a chain of BIOs which
984263bc
MD
219will be duplicated and prepended to the chain when an incoming
220connection is received. This is useful if, for example, a
8b0cefbb 221buffering or \s-1SSL\s0 \s-1BIO\s0 is required for each connection. The
984263bc 222chain of BIOs must not be freed after this call, they will
8b0cefbb 223be automatically freed when the accept \s-1BIO\s0 is freed.
984263bc 224.PP
8b0cefbb
JR
225\&\fIBIO_set_bind_mode()\fR and \fIBIO_get_bind_mode()\fR set and retrieve
226the current bind mode. If \s-1BIO_BIND_NORMAL\s0 (the default) is set
984263bc 227then another socket cannot be bound to the same port. If
8b0cefbb
JR
228\&\s-1BIO_BIND_REUSEADDR\s0 is set then other sockets can bind to the
229same port. If \s-1BIO_BIND_REUSEADDR_IF_UNUSED\s0 is set then and
230attempt is first made to use \s-1BIO_BIN_NORMAL\s0, if this fails
984263bc 231and the port is not in use then a second attempt is made
8b0cefbb 232using \s-1BIO_BIND_REUSEADDR\s0.
984263bc 233.PP
8b0cefbb
JR
234\&\fIBIO_do_accept()\fR serves two functions. When it is first
235called, after the accept \s-1BIO\s0 has been setup, it will attempt
984263bc
MD
236to create the accept socket and bind an address to it. Second
237and subsequent calls to \fIBIO_do_accept()\fR will await an incoming
238connection, or request a retry in non blocking mode.
239.SH "NOTES"
8b0cefbb
JR
240.IX Header "NOTES"
241When an accept \s-1BIO\s0 is at the end of a chain it will await an
984263bc 242incoming connection before processing I/O calls. When an accept
8b0cefbb
JR
243\&\s-1BIO\s0 is not at then end of a chain it passes I/O calls to the next
244\&\s-1BIO\s0 in the chain.
984263bc 245.PP
8b0cefbb 246When a connection is established a new socket \s-1BIO\s0 is created for
984263bc 247the connection and appended to the chain. That is the chain is now
8b0cefbb 248accept\->socket. This effectively means that attempting I/O on
984263bc
MD
249an initial accept socket will await an incoming connection then
250perform I/O on it.
251.PP
252If any additional BIOs have been set using \fIBIO_set_accept_bios()\fR
8b0cefbb
JR
253then they are placed between the socket and the accept \s-1BIO\s0,
254that is the chain will be accept\->otherbios\->socket.
984263bc
MD
255.PP
256If a server wishes to process multiple connections (as is normally
8b0cefbb 257the case) then the accept \s-1BIO\s0 must be made available for further
984263bc
MD
258incoming connections. This can be done by waiting for a connection and
259then calling:
260.PP
261.Vb 1
262\& connection = BIO_pop(accept);
263.Ve
8b0cefbb
JR
264.PP
265After this call \fBconnection\fR will contain a \s-1BIO\s0 for the recently
266established connection and \fBaccept\fR will now be a single \s-1BIO\s0
984263bc
MD
267again which can be used to await further incoming connections.
268If no further connections will be accepted the \fBaccept\fR can
269be freed using \fIBIO_free()\fR.
270.PP
271If only a single connection will be processed it is possible to
8b0cefbb
JR
272perform I/O using the accept \s-1BIO\s0 itself. This is often undesirable
273however because the accept \s-1BIO\s0 will still accept additional incoming
984263bc 274connections. This can be resolved by using \fIBIO_pop()\fR (see above)
8b0cefbb 275and freeing up the accept \s-1BIO\s0 after the initial connection.
984263bc
MD
276.PP
277If the underlying accept socket is non-blocking and \fIBIO_do_accept()\fR is
278called to await an incoming connection it is possible for
8b0cefbb 279\&\fIBIO_should_io_special()\fR with the reason \s-1BIO_RR_ACCEPT\s0. If this happens
984263bc
MD
280then it is an indication that an accept attempt would block: the application
281should take appropriate action to wait until the underlying socket has
282accepted a connection and retry the call.
283.PP
8b0cefbb
JR
284\&\fIBIO_set_accept_port()\fR, \fIBIO_get_accept_port()\fR, \fIBIO_set_nbio_accept()\fR,
285\&\fIBIO_set_accept_bios()\fR, \fIBIO_set_bind_mode()\fR, \fIBIO_get_bind_mode()\fR and
286\&\fIBIO_do_accept()\fR are macros.
984263bc 287.SH "RETURN VALUES"
8b0cefbb
JR
288.IX Header "RETURN VALUES"
289\&\s-1TBA\s0
984263bc 290.SH "EXAMPLE"
8b0cefbb 291.IX Header "EXAMPLE"
984263bc
MD
292This example accepts two connections on port 4444, sends messages
293down each and finally closes both down.
294.PP
295.Vb 3
296\& BIO *abio, *cbio, *cbio2;
297\& ERR_load_crypto_strings();
298\& abio = BIO_new_accept("4444");
aac4ff6f
PA
299.Ve
300.PP
301.Vb 6
984263bc
MD
302\& /* First call to BIO_accept() sets up accept BIO */
303\& if(BIO_do_accept(abio) <= 0) {
304\& fprintf(stderr, "Error setting up accept\en");
305\& ERR_print_errors_fp(stderr);
306\& exit(0);
307\& }
aac4ff6f
PA
308.Ve
309.PP
310.Vb 23
984263bc
MD
311\& /* Wait for incoming connection */
312\& if(BIO_do_accept(abio) <= 0) {
313\& fprintf(stderr, "Error accepting connection\en");
314\& ERR_print_errors_fp(stderr);
315\& exit(0);
316\& }
317\& fprintf(stderr, "Connection 1 established\en");
318\& /* Retrieve BIO for connection */
319\& cbio = BIO_pop(abio);
320\& BIO_puts(cbio, "Connection 1: Sending out Data on initial connection\en");
321\& fprintf(stderr, "Sent out data on connection 1\en");
322\& /* Wait for another connection */
323\& if(BIO_do_accept(abio) <= 0) {
324\& fprintf(stderr, "Error accepting connection\en");
325\& ERR_print_errors_fp(stderr);
326\& exit(0);
327\& }
328\& fprintf(stderr, "Connection 2 established\en");
329\& /* Close accept BIO to refuse further connections */
330\& cbio2 = BIO_pop(abio);
331\& BIO_free(abio);
332\& BIO_puts(cbio2, "Connection 2: Sending out Data on second\en");
333\& fprintf(stderr, "Sent out data on connection 2\en");
aac4ff6f
PA
334.Ve
335.PP
336.Vb 4
984263bc
MD
337\& BIO_puts(cbio, "Connection 1: Second connection established\en");
338\& /* Close the two established connections */
339\& BIO_free(cbio);
340\& BIO_free(cbio2);
341.Ve
342.SH "SEE ALSO"
343.IX Header "SEE ALSO"
8b0cefbb 344\&\s-1TBA\s0