SSL_accept.pod 2.2 KB
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=pod

=head1 NAME

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SSL_accept - wait for a TLS/SSL client to initiate a TLS/SSL handshake
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=head1 SYNOPSIS

 #include <openssl/ssl.h>

 int SSL_accept(SSL *ssl);

=head1 DESCRIPTION

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SSL_accept() waits for a TLS/SSL client to initiate the TLS/SSL handshake.
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The communication channel must already have been set and assigned to the
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B<ssl> by setting an underlying B<BIO>.

=head1 NOTES

The behaviour of SSL_accept() depends on the underlying BIO. 
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If the underlying BIO is B<blocking>, SSL_accept() will only return once the
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handshake has been finished or an error occurred.
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If the underlying BIO is B<non-blocking>, SSL_accept() will also return
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when the underlying BIO could not satisfy the needs of SSL_accept()
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to continue the handshake, indicating the problem by the return value -1.
In this case a call to SSL_get_error() with the
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return value of SSL_accept() will yield B<SSL_ERROR_WANT_READ> or
B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
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taking appropriate action to satisfy the needs of SSL_accept().
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

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=item Z<>0
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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
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return value B<ret> to find out the reason.

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=item Z<>1
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The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
established.

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=item E<lt>0
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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
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for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
to find out the reason.

=back

=head1 SEE ALSO

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L<SSL_get_error(3)>, L<SSL_connect(3)>,
L<SSL_shutdown(3)>, L<ssl(3)>, L<bio(3)>,
L<SSL_set_connect_state(3)>,
L<SSL_do_handshake(3)>,
L<SSL_CTX_new(3)>
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=cut