NAME
BIO_s_connect
,
BIO_new_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>
const BIO_METHOD *
BIO_s_connect
(void);
BIO *
BIO_new_connect
(const char
*name);
long
BIO_set_conn_hostname
(BIO *b,
char *name);
long
BIO_set_conn_port
(BIO *b,
char *port);
long
BIO_set_conn_ip
(BIO *b,
char *ip);
long
BIO_set_conn_int_port
(BIO *b,
char *port);
char *
BIO_get_conn_hostname
(BIO
*b);
char *
BIO_get_conn_port
(BIO *b);
char *
BIO_get_conn_ip
(BIO *b);
long
BIO_get_conn_int_port
(BIO
*b);
long
BIO_set_nbio
(BIO *b,
long n);
int
BIO_do_connect
(BIO *b);
DESCRIPTION
BIO_s_connect
()
returns the connect BIO method. This is a wrapper around 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 (see below) is set up properly, then a connection is established first.
Connect BIOs support BIO_puts(3) but not BIO_gets(3).
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(3) 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.
BIO_get_fd(3) places the underlying socket in
c if it is not NULL
and 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 forms
hostname/any/other/path or
hostname:port/any/other/path.
BIO_set_conn_port
()
sets the port to port. port is
looked up as a service using
getaddrinfo(3)
BIO_set_conn_ip
()
sets the IP address to ip using binary form i.e. four
bytes specifying the IP address in big-endian form.
BIO_set_conn_int_port
()
sets the port using port. port
should be of type int *.
BIO_get_conn_hostname
()
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.
BIO_get_conn_port
()
returns the port as a string. This return value is an internal pointer which
should not be modified.
BIO_get_conn_ip
()
returns the IP address in binary form.
BIO_get_conn_int_port
()
returns the port as an int.
BIO_set_nbio
()
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 non-blocking I/O is set
during the connect process.
BIO_new_connect
()
combines BIO_new(3) and
BIO_set_conn_hostname
() into a single call. It
creates a new connect BIO with name.
BIO_do_connect
()
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 call
BIO_should_retry(3) should be used for non-blocking connect
BIOs to determine if the call should be retried.
If blocking I/O is set then a non-positive return value from any I/O call is caused by an error condition, although 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 may 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
‘:’ 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 non-blocking I/O is set, then retries will be requested as appropriate.
In addition to
BIO_should_read(3) and
BIO_should_write(3) it is also possible for
BIO_should_io_special(3) to be true during the initial
connection process with the reason BIO_RR_CONNECT
.
If this is returned, it 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.
When a chain containing a connect BIO
is copied with
BIO_dup_chain(3),
BIO_set_conn_hostname
(),
BIO_set_conn_port
(),
BIO_set_nbio
(), and
BIO_set_info_callback(3) are called internally to
automatically copy the hostname, port, non-blocking I/O flag, and info
callback from the original BIO object to the new one.
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
(), and
BIO_do_connect
() are macros.
RETURN VALUES
BIO_s_connect
() returns the connect BIO
method.
BIO_get_fd(3) 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
if none is 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.
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
HISTORY
BIO_s_connect
(),
BIO_new_connect
(),
BIO_set_nbio
(), and
BIO_do_connect
() first appeared in SSLeay 0.8.0.
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
(), and
BIO_get_conn_int_port
() first appeared in SSLeay
0.9.0. All these functions have been available since
OpenBSD 2.4.