xref: /freebsd/crypto/openssl/doc/man3/BIO_s_connect.pod (revision 6966ac055c3b7a39266fb982493330df7a097997)
1=pod
2
3=head1 NAME
4
5BIO_set_conn_address, BIO_get_conn_address,
6BIO_s_connect, BIO_new_connect, BIO_set_conn_hostname, BIO_set_conn_port,
7BIO_set_conn_ip_family, BIO_get_conn_ip_family,
8BIO_get_conn_hostname, BIO_get_conn_port,
9BIO_set_nbio, BIO_do_connect - connect BIO
10
11=head1 SYNOPSIS
12
13 #include <openssl/bio.h>
14
15 const BIO_METHOD * BIO_s_connect(void);
16
17 BIO *BIO_new_connect(char *name);
18
19 long BIO_set_conn_hostname(BIO *b, char *name);
20 long BIO_set_conn_port(BIO *b, char *port);
21 long BIO_set_conn_address(BIO *b, BIO_ADDR *addr);
22 long BIO_set_conn_ip_family(BIO *b, long family);
23 const char *BIO_get_conn_hostname(BIO *b);
24 const char *BIO_get_conn_port(BIO *b);
25 const BIO_ADDR *BIO_get_conn_address(BIO *b);
26 const long BIO_get_conn_ip_family(BIO *b);
27
28 long BIO_set_nbio(BIO *b, long n);
29
30 int BIO_do_connect(BIO *b);
31
32=head1 DESCRIPTION
33
34BIO_s_connect() returns the connect BIO method. This is a wrapper
35round the platform's TCP/IP socket connection routines.
36
37Using connect BIOs, TCP/IP connections can be made and data
38transferred using only BIO routines. In this way any platform
39specific operations are hidden by the BIO abstraction.
40
41Read and write operations on a connect BIO will perform I/O
42on the underlying connection. If no connection is established
43and the port and hostname (see below) is set up properly then
44a connection is established first.
45
46Connect BIOs support BIO_puts() but not BIO_gets().
47
48If the close flag is set on a connect BIO then any active
49connection is shutdown and the socket closed when the BIO
50is freed.
51
52Calling BIO_reset() on a connect BIO will close any active
53connection and reset the BIO into a state where it can connect
54to the same host again.
55
56BIO_get_fd() places the underlying socket in B<c> if it is not NULL,
57it also returns the socket . If B<c> is not NULL it should be of
58type (int *).
59
60BIO_set_conn_hostname() uses the string B<name> to set the hostname.
61The hostname can be an IP address; if the address is an IPv6 one, it
62must be enclosed with brackets. The hostname can also include the
63port in the form hostname:port.
64
65BIO_set_conn_port() sets the port to B<port>. B<port> can be the
66numerical form or a string such as "http". A string will be looked
67up first using getservbyname() on the host platform but if that
68fails a standard table of port names will be used. This internal
69list is http, telnet, socks, https, ssl, ftp, and gopher.
70
71BIO_set_conn_address() sets the address and port information using
72a BIO_ADDR(3ssl).
73
74BIO_set_conn_ip_family() sets the IP family.
75
76BIO_get_conn_hostname() returns the hostname of the connect BIO or
77NULL if the BIO is initialized but no hostname is set.
78This return value is an internal pointer which should not be modified.
79
80BIO_get_conn_port() returns the port as a string.
81This return value is an internal pointer which should not be modified.
82
83BIO_get_conn_address() returns the address information as a BIO_ADDR.
84This return value is an internal pointer which should not be modified.
85
86BIO_get_conn_ip_family() returns the IP family of the connect BIO.
87
88BIO_set_nbio() sets the non blocking I/O flag to B<n>. If B<n> is
89zero then blocking I/O is set. If B<n> is 1 then non blocking I/O
90is set. Blocking I/O is the default. The call to BIO_set_nbio()
91should be made before the connection is established because
92non blocking I/O is set during the connect process.
93
94BIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into
95a single call: that is it creates a new connect BIO with B<name>.
96
97BIO_do_connect() attempts to connect the supplied BIO. It returns 1
98if the connection was established successfully. A zero or negative
99value is returned if the connection could not be established, the
100call BIO_should_retry() should be used for non blocking connect BIOs
101to determine if the call should be retried.
102
103=head1 NOTES
104
105If blocking I/O is set then a non positive return value from any
106I/O call is caused by an error condition, although a zero return
107will normally mean that the connection was closed.
108
109If the port name is supplied as part of the host name then this will
110override any value set with BIO_set_conn_port(). This may be undesirable
111if the application does not wish to allow connection to arbitrary
112ports. This can be avoided by checking for the presence of the ':'
113character in the passed hostname and either indicating an error or
114truncating the string at that point.
115
116The values returned by BIO_get_conn_hostname(), BIO_get_conn_address(),
117and BIO_get_conn_port() are updated when a connection attempt is made.
118Before any connection attempt the values returned are those set by the
119application itself.
120
121Applications do not have to call BIO_do_connect() but may wish to do
122so to separate the connection process from other I/O processing.
123
124If non blocking I/O is set then retries will be requested as appropriate.
125
126It addition to BIO_should_read() and BIO_should_write() it is also
127possible for BIO_should_io_special() to be true during the initial
128connection process with the reason BIO_RR_CONNECT. If this is returned
129then this is an indication that a connection attempt would block,
130the application should then take appropriate action to wait until
131the underlying socket has connected and retry the call.
132
133BIO_set_conn_hostname(), BIO_set_conn_port(), BIO_get_conn_hostname(),
134BIO_set_conn_address(), BIO_get_conn_port(), BIO_get_conn_address(),
135BIO_set_conn_ip_family(), BIO_get_conn_ip_family(),
136BIO_set_nbio(), and BIO_do_connect() are macros.
137
138=head1 RETURN VALUES
139
140BIO_s_connect() returns the connect BIO method.
141
142BIO_get_fd() returns the socket or -1 if the BIO has not
143been initialized.
144
145BIO_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family()
146always return 1.
147
148BIO_set_conn_hostname() returns 1 on success and 0 on failure.
149
150BIO_get_conn_address() returns the address information or NULL if none
151was set.
152
153BIO_get_conn_hostname() returns the connected hostname or NULL if
154none was set.
155
156BIO_get_conn_ip_family() returns the address family or -1 if none was set.
157
158BIO_get_conn_port() returns a string representing the connected
159port or NULL if not set.
160
161BIO_set_nbio() always returns 1.
162
163BIO_do_connect() returns 1 if the connection was successfully
164established and 0 or -1 if the connection failed.
165
166=head1 EXAMPLES
167
168This is example connects to a webserver on the local host and attempts
169to retrieve a page and copy the result to standard output.
170
171
172 BIO *cbio, *out;
173 int len;
174 char tmpbuf[1024];
175
176 cbio = BIO_new_connect("localhost:http");
177 out = BIO_new_fp(stdout, BIO_NOCLOSE);
178 if (BIO_do_connect(cbio) <= 0) {
179     fprintf(stderr, "Error connecting to server\n");
180     ERR_print_errors_fp(stderr);
181     exit(1);
182 }
183 BIO_puts(cbio, "GET / HTTP/1.0\n\n");
184 for (;;) {
185     len = BIO_read(cbio, tmpbuf, 1024);
186     if (len <= 0)
187         break;
188     BIO_write(out, tmpbuf, len);
189 }
190 BIO_free(cbio);
191 BIO_free(out);
192
193
194=head1 SEE ALSO
195
196L<BIO_ADDR(3)>
197
198=head1 HISTORY
199
200BIO_set_conn_int_port(), BIO_get_conn_int_port(), BIO_set_conn_ip(), and BIO_get_conn_ip()
201were removed in OpenSSL 1.1.0.
202Use BIO_set_conn_address() and BIO_get_conn_address() instead.
203
204=head1 COPYRIGHT
205
206Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
207
208Licensed under the OpenSSL license (the "License").  You may not use
209this file except in compliance with the License.  You can obtain a copy
210in the file LICENSE in the source distribution or at
211L<https://www.openssl.org/source/license.html>.
212
213=cut
214