BIO_seed() and BIO_tell() were documented in two other documents,

[thirdparty/openssl.git] / doc / crypto / BIO_s_connect.pod

=pod

=head1 NAME

BIO_s_connect - connect BIO

=head1 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_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)

=head1 DESCRIPTION

BIO_s_connect() 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 (see below) 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.

BIO_get_fd() places the underlying socket in B<c> if it is not NULL,
it also returns the socket . If B<c> is not NULL it should be of
type (int *).

BIO_set_conn_hostname() uses the string B<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".

BIO_set_conn_port() sets the port to B<port>. B<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.

BIO_set_conn_ip() sets the IP address to B<ip> using binary form,
that is four bytes specifying the IP address in big endian form.

BIO_set_conn_int_port() sets the port using B<port>. B<port> should
be of type (int *).

BIO_get_conn_hostname() returns the hostname of the connect BIO or
NULL if the BIO is initialised 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.

BIO_get_conn_ip() returns the IP address in binary form.

BIO_get_conn_int_port() returns the host name as an int.

BIO_set_nbio() sets the non blocking I/O flag to B<n>. If B<n> is
zero then blocking I/O is set. If B<n> is 1 then non blocking I/O
is set.

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() should be used for non blocking connect BIOs
to determine if the call should be retried.


=head1 NOTES

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().

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 can 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.

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 appropiate action to wait until
the underlying socket has connected and retry the call.

=head1 RETURN VALUES

BIO_s_connect() returns the connect BIO method.

BIO_get_fd() returns the socket or -1 if the BIO has not
been initialised.

=head1 EXAMPLES

TBA

=head1 SEE ALSO

TBA