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BIO_s_connect(3)
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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
#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_CONNECT,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)
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 hostname/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 connect 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.
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 undesirable 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 connection
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 appropriate.
It addition to BIO_should_read() and BIO_should_write() it
is also possible for BIO_should_io_special() to be true
during the initial connection process with the reason
BIO_RR_CONNECT. If this is returned then this is an indication
that a connection attempt would block. The application
should then take appropriate action to wait until the
underlying socket has connected and retry the call.
BIO_s_connect() returns the connect BIO method.
BIO_get_fd() returns the socket or -1 if the BIO has not
been initialized.
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
established and 0 or -1 if the connection failed.
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);
TBA
BIO_s_connect(3)
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