1=pod 2 3=head1 NAME 4 5BIO_s_connect, BIO_new_connect, 6BIO_set_conn_hostname, BIO_set_conn_port, 7BIO_set_conn_address, BIO_set_conn_ip_family, 8BIO_get_conn_hostname, BIO_get_conn_port, 9BIO_get_conn_address, BIO_get_conn_ip_family, 10BIO_set_nbio, BIO_do_connect - connect BIO 11 12=head1 SYNOPSIS 13 14 #include <openssl/bio.h> 15 16 const BIO_METHOD *BIO_s_connect(void); 17 18 BIO *BIO_new_connect(const char *name); 19 20 long BIO_set_conn_hostname(BIO *b, char *name); 21 long BIO_set_conn_port(BIO *b, char *port); 22 long BIO_set_conn_address(BIO *b, BIO_ADDR *addr); 23 long BIO_set_conn_ip_family(BIO *b, long family); 24 const char *BIO_get_conn_hostname(BIO *b); 25 const char *BIO_get_conn_port(BIO *b); 26 const BIO_ADDR *BIO_get_conn_address(BIO *b); 27 const long BIO_get_conn_ip_family(BIO *b); 28 29 long BIO_set_nbio(BIO *b, long n); 30 31 int BIO_do_connect(BIO *b); 32 33=head1 DESCRIPTION 34 35BIO_s_connect() returns the connect BIO method. This is a wrapper 36round the platform's TCP/IP socket connection routines. 37 38Using connect BIOs, TCP/IP connections can be made and data 39transferred using only BIO routines. In this way any platform 40specific operations are hidden by the BIO abstraction. 41 42Read and write operations on a connect BIO will perform I/O 43on the underlying connection. If no connection is established 44and the port and hostname (see below) is set up properly then 45a connection is established first. 46 47Connect BIOs support BIO_puts() and BIO_gets(). 48 49If the close flag is set on a connect BIO then any active 50connection is shutdown and the socket closed when the BIO 51is freed. 52 53Calling BIO_reset() on a connect BIO will close any active 54connection and reset the BIO into a state where it can connect 55to the same host again. 56 57BIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into 58a single call: that is it creates a new connect BIO with hostname B<name>. 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 C<[> and C<]>. 63The hostname can also include the port in the form hostname:port; 64see L<BIO_parse_hostserv(3)> and BIO_set_conn_port() for details. 65 66BIO_set_conn_port() sets the port to B<port>. B<port> can be the 67numerical form or a service string such as "http", which 68will be mapped to a port number using the system function getservbyname(). 69 70BIO_set_conn_address() sets the address and port information using 71a BIO_ADDR(3ssl). 72 73BIO_set_conn_ip_family() sets the IP family. 74 75BIO_get_conn_hostname() returns the hostname of the connect BIO or 76NULL if the BIO is initialized but no hostname is set. 77This return value is an internal pointer which should not be modified. 78 79BIO_get_conn_port() returns the port as a string. 80This return value is an internal pointer which should not be modified. 81 82BIO_get_conn_address() returns the address information as a BIO_ADDR. 83This return value is an internal pointer which should not be modified. 84 85BIO_get_conn_ip_family() returns the IP family of the connect BIO. 86 87BIO_set_nbio() sets the non blocking I/O flag to B<n>. If B<n> is 88zero then blocking I/O is set. If B<n> is 1 then non blocking I/O 89is set. Blocking I/O is the default. The call to BIO_set_nbio() 90should be made before the connection is established because 91non blocking I/O is set during the connect process. 92 93BIO_do_connect() attempts to connect the supplied BIO. 94This performs an SSL/TLS handshake as far as supported by the BIO. 95For non-SSL BIOs the connection is done typically at TCP level. 96If domain name resolution yields multiple IP addresses all of them are tried 97after connect() failures. 98The function returns 1 if the connection was established successfully. 99A zero or negative value is returned if the connection could not be established. 100The call BIO_should_retry() should be used for non blocking connect BIOs 101to determine if the call should be retried. 102If a connection has already been established this call has no effect. 103 104=head1 NOTES 105 106If blocking I/O is set then a non positive return value from any 107I/O call is caused by an error condition, although a zero return 108will normally mean that the connection was closed. 109 110If the port name is supplied as part of the hostname then this will 111override any value set with BIO_set_conn_port(). This may be undesirable 112if the application does not wish to allow connection to arbitrary 113ports. This can be avoided by checking for the presence of the ':' 114character in the passed hostname and either indicating an error or 115truncating the string at that point. 116 117The values returned by BIO_get_conn_hostname(), BIO_get_conn_address(), 118and BIO_get_conn_port() are updated when a connection attempt is made. 119Before any connection attempt the values returned are those set by the 120application itself. 121 122Applications do not have to call BIO_do_connect() but may wish to do 123so to separate the connection process from other I/O processing. 124 125If non blocking I/O is set then retries will be requested as appropriate. 126 127It addition to BIO_should_read() and BIO_should_write() it is also 128possible for BIO_should_io_special() to be true during the initial 129connection process with the reason BIO_RR_CONNECT. If this is returned 130then this is an indication that a connection attempt would block, 131the application should then take appropriate action to wait until 132the underlying socket has connected and retry the call. 133 134BIO_set_conn_hostname(), BIO_set_conn_port(), BIO_get_conn_hostname(), 135BIO_set_conn_address(), BIO_get_conn_port(), BIO_get_conn_address(), 136BIO_set_conn_ip_family(), BIO_get_conn_ip_family(), 137BIO_set_nbio(), and BIO_do_connect() are macros. 138 139=head1 RETURN VALUES 140 141BIO_s_connect() returns the connect BIO method. 142 143BIO_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family() 144return 1 or <=0 if an error occurs. 145 146BIO_set_conn_hostname() returns 1 on success and <=0 on failure. 147 148BIO_get_conn_address() returns the address information or NULL if none 149was set. 150 151BIO_get_conn_hostname() returns the connected hostname or NULL if 152none was set. 153 154BIO_get_conn_ip_family() returns the address family or -1 if none was set. 155 156BIO_get_conn_port() returns a string representing the connected 157port or NULL if not set. 158 159BIO_set_nbio() returns 1 or <=0 if an error occurs. 160 161BIO_do_connect() returns 1 if the connection was successfully 162established and <=0 if the connection failed. 163 164=head1 EXAMPLES 165 166This is example connects to a webserver on the local host and attempts 167to retrieve a page and copy the result to standard output. 168 169 170 BIO *cbio, *out; 171 int len; 172 char tmpbuf[1024]; 173 174 cbio = BIO_new_connect("localhost:http"); 175 out = BIO_new_fp(stdout, BIO_NOCLOSE); 176 if (BIO_do_connect(cbio) <= 0) { 177 fprintf(stderr, "Error connecting to server\n"); 178 ERR_print_errors_fp(stderr); 179 exit(1); 180 } 181 BIO_puts(cbio, "GET / HTTP/1.0\n\n"); 182 for (;;) { 183 len = BIO_read(cbio, tmpbuf, 1024); 184 if (len <= 0) 185 break; 186 BIO_write(out, tmpbuf, len); 187 } 188 BIO_free(cbio); 189 BIO_free(out); 190 191 192=head1 SEE ALSO 193 194L<BIO_ADDR(3)>, L<BIO_parse_hostserv(3)> 195 196=head1 HISTORY 197 198BIO_set_conn_int_port(), BIO_get_conn_int_port(), BIO_set_conn_ip(), and BIO_get_conn_ip() 199were removed in OpenSSL 1.1.0. 200Use BIO_set_conn_address() and BIO_get_conn_address() instead. 201 202Connect BIOs support BIO_gets() since OpenSSL 3.1. 203 204=head1 COPYRIGHT 205 206Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved. 207 208Licensed under the Apache License 2.0 (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
