BIO_s_connect(3)BIO_s_connect(3)NAME
BIO_s_connect, BIO_set_conn_hostname, BIO_set_conn_port,
BIO_set_conn_ip, BIO_set_conn_int_port, BIO_get_conn_hostname,
BIO_get_conn_port, BIO_get_conn_ip, BIO_get_conn_int_port,
BIO_set_nbio, BIO_do_connect - Connect BIO
SYNOPSIS
#include <openssl/bio.h>
BIO_METHOD * BIO_s_connect(
void ); #define BIO_set_conn_hostname(b,name)
BIO_ctrl(b,BIO_C_SET_CONNECT,0,(char *)name) #define
BIO_set_conn_port(b,port) BIO_ctrl(b,BIO_C_SET_CONNECT,1,(char *)port)
#define BIO_set_conn_ip(b,ip) BIO_ctrl(b,BIO_C_SET_CONNECT,2,(char
*)ip) #define BIO_set_conn_int_port(b,port) BIO_ctrl(b,BIO_C_SET_CON‐
NECT,3,(char *)port) #define BIO_get_conn_hostname(b)
BIO_ptr_ctrl(b,BIO_C_GET_CONNECT,0) #define BIO_get_conn_port(b)
BIO_ptr_ctrl(b,BIO_C_GET_CONNECT,1) #define BIO_get_conn_ip(b,ip)
BIO_ptr_ctrl(b,BIO_C_SET_CONNECT,2) #define
BIO_get_conn_int_port(b,port) BIO_int_ctrl(b,BIO_C_SET_CONNECT,3,port)
#define BIO_set_nbio(b,n) BIO_ctrl(b,BIO_C_SET_NBIO,(n),NULL)
#define BIO_do_connect(b)BIO_do_handshake(b)DESCRIPTION
The BIO_s_connect() function returns the connect BIO method. This is a
wrapper round the platform's TCP/IP socket connection routines.
Using connect BIOs TCP/IP connections can be made and data transferred
using only BIO routines. In this way any platform specific operations
are hidden by the BIO abstraction.
Read and write operations on a connect BIO will perform I/O on the
underlying connection. If no connection is established and the port and
hostname is set up properly then a connection is established first.
Connect BIOs support BIO_puts() but not BIO_gets().
If the close flag is set on a connect BIO then any active connection is
shutdown and the socket closed when the BIO is freed.
Calling BIO_reset() on a connect BIO will close any active connection
and reset the BIO into a state where it can connect to the same host
again.
The BIO_get_fd() function places the underlying socket in c if it is
not NULL. It also returns the socket . If c is not NULL it should be of
type (int *).
BIO_set_conn_hostname() uses the string name to set the hostname. The
hostname can be an IP address. The hostname can also include the port
in the form hostname:port. It is also acceptable to use the form host‐
name/any/other/path or hostname:port/any/other/path.
The BIO_set_conn_port() function sets the port to port. The port can be
the numerical form or a string such as http. A string will be looked up
first using getservbyname() on the host platform, but if that fails a
standard table of port names will be used. Currently the list is http,
telnet, socks, https, ssl, ftp, gopher and wais.
The BIO_set_conn_ip() function sets the IP address to ip using binary
form, that is four bytes specifying the IP address in big-endian form.
The BIO_set_conn_int_port() function sets the port using port. The port
should be of type (int *).
The BIO_get_conn_hostname() function returns the hostname of the con‐
nect BIO or NULL if the BIO is initialized but no hostname is set. This
return value is an internal pointer which should not be modified.
The BIO_get_conn_port() functon returns the port as a string.
The BIO_get_conn_ip() function returns the IP address in binary form.
The BIO_get_conn_int_port() function returns the port as an int.
The BIO_set_nbio() function sets the non blocking I/O flag to n. If n
is zero then blocking I/O is set. If n is 1 then non blocking I/O is
set. Blocking I/O is the default. The call to BIO_set_nbio() should be
made before the connection is established because nonblocking I/O is
set during the connect process.
The BIO_do_connect() function attempts to connect the supplied BIO. It
returns 1 if the connection was established successfully. A zero or
negative value is returned if the connection could not be established.
The BIO_should_retry() function should be used for nonblocking connect
BIOs to determine if the call should be retried.
NOTES
If blocking I/O is set, then a nonpositive return value from any I/O
call is caused by an error condition. A zero return will normally mean
that the connection was closed.
If the port name is supplied as part of the host name then this will
override any value set with BIO_set_conn_port(). This might be undesir‐
able if the application does not wish to allow connection to arbitrary
ports. This can be avoided by checking for the presence of the colon
(:) character in the passed hostname, and either indicating an error or
truncating the string at that point.
The values returned by BIO_get_conn_hostname(), BIO_get_conn_port(),
BIO_get_conn_ip(), and BIO_get_conn_int_port() are updated when a con‐
nection attempt is made. Before any connection attempt the values
returned are those set by the application itself.
Applications do not have to call BIO_do_connect() but may wish to do so
to separate the connection process from other I/O processing.
If nonblocking I/O is set then retries will be requested as appropri‐
ate.
It addition to BIO_should_read() and BIO_should_write() it is also pos‐
sible for BIO_should_io_special() to be true during the initial connec‐
tion process with the reason BIO_RR_CONNECT. If this is returned then
this is an indication that a connection attempt would block. The appli‐
cation should then take appropriate action to wait until the underlying
socket has connected and retry the call.
RETURN VALUESBIO_s_connect() returns the connect BIO method.
BIO_get_fd() returns the socket or -1 if the BIO has not been initial‐
ized.
BIO_set_conn_hostname(), BIO_set_conn_port(), BIO_set_conn_ip(), and
BIO_set_conn_int_port() always return 1.
BIO_get_conn_hostname() returns the connected hostname or NULL is none
was set.
BIO_get_conn_port() returns a string representing the connected port or
NULL if not set.
BIO_get_conn_ip() returns a pointer to the connected IP address in
binary form or all zeros if not set.
BIO_get_conn_int_port() returns the connected port or 0 if none was
set.
BIO_set_nbio() always returns 1.
BIO_do_connect() returns 1 if the connection was successfully estab‐
lished and 0 or -1 if the connection failed.
EXAMPLES
This example connects to a webserver on the local host and attempts to
retrieve a page and copy the result to standard output. BIO *cbio,
*out; int len; char tmpbuf[1024]; ERR_load_crypto_strings(); cbio =
BIO_new_connect("localhost:http"); out = BIO_new_fp(stdout,
BIO_NOCLOSE); if(BIO_do_connect(cbio) <= 0) {fprintf(stderr,
"Error connecting to server\n"); ERR_print_errors_fp(stderr);
/* whatever ... */ } BIO_puts(cbio, "GET /
HTTP/1.0\n\n"); for(;;) { len = BIO_read(cbio, tmpbuf, 1024);
if(len <= 0) break; BIO_write(out, tmpbuf, len); }
BIO_free(cbio); BIO_free(out);
SEE ALSO
TBA
BIO_s_connect(3)