[thirdparty/openssl.git] / doc / man3 / SSL_connect.pod

=pod

=head1 NAME

SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_connect(SSL *ssl);

=head1 DESCRIPTION

SSL_connect() initiates the TLS/SSL handshake with a server. The communication
channel must already have been set and assigned to the B<ssl> by setting an
underlying B<BIO>.

=head1 NOTES

The behaviour of SSL_connect() depends on the underlying BIO.

If the underlying BIO is B<blocking>, SSL_connect() will only return once the
handshake has been finished or an error occurred.

If the underlying BIO is B<non-blocking>, SSL_connect() will also return
when the underlying BIO could not satisfy the needs of SSL_connect()
to continue the handshake, indicating the problem by the return value -1.
In this case a call to SSL_get_error() with the
return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
taking appropriate action to satisfy the needs of SSL_connect().
The action depends on the underlying BIO. When using a non-blocking socket,
nothing is to be done, but select() can be used to check for the required
condition. When using a buffering BIO, like a BIO pair, data must be written
into or retrieved out of the BIO before being able to continue.

=head1 RETURN VALUES

The following return values can occur:

=over 4

=item Z<>0

The TLS/SSL handshake was not successful but was shut down controlled and
by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
return value B<ret> to find out the reason.

=item Z<>1

The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
established.

=item E<lt>0

The TLS/SSL handshake was not successful, because a fatal error occurred either
at the protocol level or a connection failure occurred. The shutdown was
not clean. It can also occur of action is need to continue the operation
for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
to find out the reason.

=back

=head1 SEE ALSO

L<SSL_get_error(3)>, L<SSL_accept(3)>,
L<SSL_shutdown(3)>, L<ssl(7)>, L<bio(7)>,
L<SSL_set_connect_state(3)>,
L<SSL_do_handshake(3)>,
L<SSL_CTX_new(3)>

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
Commit	Line	Data
cc99526d RL	1	=pod
	2
	3	=head1 NAME
	4
1e4e5492	5	SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
cc99526d RL	6
	7	=head1 SYNOPSIS
	8
	9	#include <openssl/ssl.h>
	10
	11	int SSL_connect(SSL *ssl);
	12
	13	=head1 DESCRIPTION
	14
318f9629	15	SSL_connect() initiates the TLS/SSL handshake with a server. The communication
cc99526d	16	channel must already have been set and assigned to the B<ssl> by setting an
c19b6c92 RL	17	underlying B<BIO>.
	18
	19	=head1 NOTES
	20
1bc74519	21	The behaviour of SSL_connect() depends on the underlying BIO.
cc99526d	22
1e4e5492 UM	23	If the underlying BIO is B<blocking>, SSL_connect() will only return once the
1e4e5492 UM	24	handshake has been finished or an error occurred.
cc99526d	25
1e4e5492	26	If the underlying BIO is B<non-blocking>, SSL_connect() will also return
cc99526d	27	when the underlying BIO could not satisfy the needs of SSL_connect()
db017469 LJ	28	to continue the handshake, indicating the problem by the return value -1.
db017469 LJ	29	In this case a call to SSL_get_error() with the
1e4e5492 UM	30	return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
1e4e5492 UM	31	B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
cc99526d RL	32	taking appropriate action to satisfy the needs of SSL_connect().
	33	The action depends on the underlying BIO. When using a non-blocking socket,
	34	nothing is to be done, but select() can be used to check for the required
	35	condition. When using a buffering BIO, like a BIO pair, data must be written
	36	into or retrieved out of the BIO before being able to continue.
	37
	38	=head1 RETURN VALUES
	39
	40	The following return values can occur:
	41
	42	=over 4
	43
c8919dde	44	=item Z<>0
cc99526d	45
1e4e5492 UM	46	The TLS/SSL handshake was not successful but was shut down controlled and
1e4e5492 UM	47	by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
cc99526d RL	48	return value B<ret> to find out the reason.
cc99526d RL	49
c8919dde	50	=item Z<>1
5cc27077 NA	51
	52	The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
	53	established.
	54
53fe8d5b	55	=item E<lt>0
cc99526d	56
1e4e5492 UM	57	The TLS/SSL handshake was not successful, because a fatal error occurred either
	58	at the protocol level or a connection failure occurred. The shutdown was
	59	not clean. It can also occur of action is need to continue the operation
cc99526d RL	60	for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
	61	to find out the reason.
	62
	63	=back
	64
	65	=head1 SEE ALSO
	66
9b86974e	67	L<SSL_get_error(3)>, L<SSL_accept(3)>,
b97fdb57	68	L<SSL_shutdown(3)>, L<ssl(7)>, L<bio(7)>,
9b86974e RS	69	L<SSL_set_connect_state(3)>,
	70	L<SSL_do_handshake(3)>,
	71	L<SSL_CTX_new(3)>
cc99526d	72
e2f92610 RS	73	=head1 COPYRIGHT
	74
	75	Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
	76
	77	Licensed under the OpenSSL license (the "License"). You may not use
	78	this file except in compliance with the License. You can obtain a copy
	79	in the file LICENSE in the source distribution or at
	80	L<https://www.openssl.org/source/license.html>.
	81
	82	=cut