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_set_sock_type, BIO_get_sock_type, BIO_get0_dgram_bio, 11BIO_do_connect - connect BIO 12 13=head1 SYNOPSIS 14 15 #include <openssl/bio.h> 16 17 const BIO_METHOD *BIO_s_connect(void); 18 19 BIO *BIO_new_connect(const char *name); 20 21 long BIO_set_conn_hostname(BIO *b, char *name); 22 long BIO_set_conn_port(BIO *b, char *port); 23 long BIO_set_conn_address(BIO *b, BIO_ADDR *addr); 24 long BIO_set_conn_ip_family(BIO *b, long family); 25 const char *BIO_get_conn_hostname(BIO *b); 26 const char *BIO_get_conn_port(BIO *b); 27 const BIO_ADDR *BIO_get_conn_address(BIO *b); 28 const long BIO_get_conn_ip_family(BIO *b); 29 30 long BIO_set_nbio(BIO *b, long n); 31 32 int BIO_set_sock_type(BIO *b, int sock_type); 33 int BIO_get_sock_type(BIO *b); 34 int BIO_get0_dgram_bio(BIO *B, BIO **dgram_bio); 35 36 long BIO_do_connect(BIO *b); 37 38=head1 DESCRIPTION 39 40BIO_s_connect() returns the connect BIO method. This is a wrapper 41round the platform's TCP/IP socket connection routines. 42 43Using connect BIOs, TCP/IP connections can be made and data 44transferred using only BIO routines. In this way any platform 45specific operations are hidden by the BIO abstraction. 46 47Read and write operations on a connect BIO will perform I/O 48on the underlying connection. If no connection is established 49and the port and hostname (see below) is set up properly then 50a connection is established first. 51 52Connect BIOs support BIO_puts() and BIO_gets(). 53 54If the close flag is set on a connect BIO then any active 55connection is shutdown and the socket closed when the BIO 56is freed. 57 58Calling BIO_reset() on a connect BIO will close any active 59connection and reset the BIO into a state where it can connect 60to the same host again. 61 62BIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into 63a single call: that is it creates a new connect BIO with hostname B<name>. 64 65BIO_set_conn_hostname() uses the string B<name> to set the hostname. 66The hostname can be an IP address; if the address is an IPv6 one, it 67must be enclosed with brackets C<[> and C<]>. 68The hostname can also include the port in the form hostname:port; 69see L<BIO_parse_hostserv(3)> and BIO_set_conn_port() for details. 70 71BIO_set_conn_port() sets the port to B<port>. B<port> can be the 72numerical form or a service string such as "http", which 73will be mapped to a port number using the system function getservbyname(). 74 75BIO_set_conn_address() sets the address and port information using 76a BIO_ADDR(3ssl). 77 78BIO_set_conn_ip_family() sets the IP family. 79 80BIO_get_conn_hostname() returns the hostname of the connect BIO or 81NULL if the BIO is initialized but no hostname is set. 82This return value is an internal pointer which should not be modified. 83 84BIO_get_conn_port() returns the port as a string. 85This return value is an internal pointer which should not be modified. 86 87BIO_get_conn_address() returns the address information as a BIO_ADDR. 88This return value is an internal pointer which should not be modified. 89 90BIO_get_conn_ip_family() returns the IP family of the connect BIO. 91 92BIO_set_nbio() sets the non blocking I/O flag to B<n>. If B<n> is 93zero then blocking I/O is set. If B<n> is 1 then non blocking I/O 94is set. Blocking I/O is the default. The call to BIO_set_nbio() 95should be made before the connection is established because 96non blocking I/O is set during the connect process. 97 98BIO_do_connect() attempts to connect the supplied BIO. 99This performs an SSL/TLS handshake as far as supported by the BIO. 100For non-SSL BIOs the connection is done typically at TCP level. 101If domain name resolution yields multiple IP addresses all of them are tried 102after connect() failures. 103The function returns 1 if the connection was established successfully. 104A zero or negative value is returned if the connection could not be established. 105The call BIO_should_retry() should be used for non blocking connect BIOs 106to determine if the call should be retried. 107If a connection has already been established this call has no effect. 108 109BIO_set_sock_type() can be used to set a socket type value as would be passed in 110a call to socket(2). The only currently supported values are B<SOCK_STREAM> (the 111default) and B<SOCK_DGRAM>. If B<SOCK_DGRAM> is configured, the connection 112created is a UDP datagram socket handled via L<BIO_s_datagram(3)>. 113I/O calls such as L<BIO_read(3)> and L<BIO_write(3)> are forwarded transparently 114to an internal L<BIO_s_datagram(3)> instance. The created L<BIO_s_datagram(3)> 115instance can be retrieved using BIO_get0_dgram_bio() if desired, which writes 116a pointer to the L<BIO_s_datagram(3)> instance to I<*dgram_bio>. The lifetime 117of the internal L<BIO_s_datagram(3)> is managed by BIO_s_connect() and does not 118need to be freed by the caller. 119 120BIO_get_sock_type() retrieves the value set using BIO_set_sock_type(). 121 122=head1 NOTES 123 124If blocking I/O is set then a non positive return value from any 125I/O call is caused by an error condition, although a zero return 126will normally mean that the connection was closed. 127 128If the port name is supplied as part of the hostname then this will 129override any value set with BIO_set_conn_port(). This may be undesirable 130if the application does not wish to allow connection to arbitrary 131ports. This can be avoided by checking for the presence of the ':' 132character in the passed hostname and either indicating an error or 133truncating the string at that point. 134 135The values returned by BIO_get_conn_hostname(), BIO_get_conn_address(), 136and BIO_get_conn_port() are updated when a connection attempt is made. 137Before any connection attempt the values returned are those set by the 138application itself. 139 140Applications do not have to call BIO_do_connect() but may wish to do 141so to separate the connection process from other I/O processing. 142 143If non blocking I/O is set then retries will be requested as appropriate. 144 145It addition to BIO_should_read() and BIO_should_write() it is also 146possible for BIO_should_io_special() to be true during the initial 147connection process with the reason BIO_RR_CONNECT. If this is returned 148then this is an indication that a connection attempt would block, 149the application should then take appropriate action to wait until 150the underlying socket has connected and retry the call. 151 152BIO_set_conn_hostname(), BIO_set_conn_port(), BIO_get_conn_hostname(), 153BIO_set_conn_address(), BIO_get_conn_port(), BIO_get_conn_address(), 154BIO_set_conn_ip_family(), BIO_get_conn_ip_family(), 155BIO_set_nbio(), and BIO_do_connect() are macros. 156 157=head1 RETURN VALUES 158 159BIO_s_connect() returns the connect BIO method. 160 161BIO_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family() 162return 1 or <=0 if an error occurs. 163 164BIO_set_conn_hostname() returns 1 on success and <=0 on failure. 165 166BIO_get_conn_address() returns the address information or NULL if none 167was set. 168 169BIO_get_conn_hostname() returns the connected hostname or NULL if 170none was set. 171 172BIO_get_conn_ip_family() returns the address family or -1 if none was set. 173 174BIO_get_conn_port() returns a string representing the connected 175port or NULL if not set. 176 177BIO_set_nbio() returns 1 or <=0 if an error occurs. 178 179BIO_do_connect() returns 1 if the connection was successfully 180established and <=0 if the connection failed. 181 182BIO_set_sock_type() returns 1 on success or 0 on failure. 183 184BIO_get_sock_type() returns a socket type or 0 if the call is not supported. 185 186BIO_get0_dgram_bio() returns 1 on success or 0 on failure. 187 188=head1 EXAMPLES 189 190This is example connects to a webserver on the local host and attempts 191to retrieve a page and copy the result to standard output. 192 193 194 BIO *cbio, *out; 195 int len; 196 char tmpbuf[1024]; 197 198 cbio = BIO_new_connect("localhost:http"); 199 out = BIO_new_fp(stdout, BIO_NOCLOSE); 200 if (BIO_do_connect(cbio) <= 0) { 201 fprintf(stderr, "Error connecting to server\n"); 202 ERR_print_errors_fp(stderr); 203 exit(1); 204 } 205 BIO_puts(cbio, "GET / HTTP/1.0\n\n"); 206 for (;;) { 207 len = BIO_read(cbio, tmpbuf, 1024); 208 if (len <= 0) 209 break; 210 BIO_write(out, tmpbuf, len); 211 } 212 BIO_free(cbio); 213 BIO_free(out); 214 215 216=head1 SEE ALSO 217 218L<BIO_ADDR(3)>, L<BIO_parse_hostserv(3)> 219 220=head1 HISTORY 221 222BIO_set_conn_int_port(), BIO_get_conn_int_port(), BIO_set_conn_ip(), and BIO_get_conn_ip() 223were removed in OpenSSL 1.1.0. 224Use BIO_set_conn_address() and BIO_get_conn_address() instead. 225 226Connect BIOs support BIO_gets() since OpenSSL 3.2. 227 228=head1 COPYRIGHT 229 230Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. 231 232Licensed under the Apache License 2.0 (the "License"). You may not use 233this file except in compliance with the License. You can obtain a copy 234in the file LICENSE in the source distribution or at 235L<https://www.openssl.org/source/license.html>. 236 237=cut 238
