1=pod 2 3=head1 NAME 4 5SSL_accept - wait for a TLS/SSL client to initiate a TLS/SSL handshake 6 7=head1 SYNOPSIS 8 9 #include <openssl/ssl.h> 10 11 int SSL_accept(SSL *ssl); 12 13=head1 DESCRIPTION 14 15SSL_accept() waits for a TLS/SSL client to initiate the TLS/SSL handshake. 16The communication channel must already have been set and assigned to the 17B<ssl> by setting an underlying B<BIO>. 18 19=head1 NOTES 20 21The behaviour of SSL_accept() depends on the underlying BIO. 22 23If the underlying BIO is B<blocking>, SSL_accept() will only return once the 24handshake has been finished or an error occurred, except for SGC (Server 25Gated Cryptography). For SGC, SSL_accept() may return with -1, but 26SSL_get_error() will yield B<SSL_ERROR_WANT_READ/WRITE> and SSL_accept() 27should be called again. 28 29If the underlying BIO is B<non-blocking>, SSL_accept() will also return 30when the underlying BIO could not satisfy the needs of SSL_accept() 31to continue the handshake, indicating the problem by the return value -1. 32In this case a call to SSL_get_error() with the 33return value of SSL_accept() will yield B<SSL_ERROR_WANT_READ> or 34B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after 35taking appropriate action to satisfy the needs of SSL_accept(). 36The action depends on the underlying BIO. When using a non-blocking socket, 37nothing is to be done, but select() can be used to check for the required 38condition. When using a buffering BIO, like a BIO pair, data must be written 39into or retrieved out of the BIO before being able to continue. 40 41=head1 RETURN VALUES 42 43The following return values can occur: 44 45=over 4 46 47=item 1 48 49The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been 50established. 51 52=item 0 53 54The TLS/SSL handshake was not successful but was shut down controlled and 55by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the 56return value B<ret> to find out the reason. 57 58=item E<lt>0 59 60The TLS/SSL handshake was not successful because a fatal error occurred either 61at the protocol level or a connection failure occurred. The shutdown was 62not clean. It can also occur of action is need to continue the operation 63for non-blocking BIOs. Call SSL_get_error() with the return value B<ret> 64to find out the reason. 65 66=back 67 68=head1 SEE ALSO 69 70L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_connect(3)|SSL_connect(3)>, 71L<SSL_shutdown(3)|SSL_shutdown(3)>, L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>, 72L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>, 73L<SSL_do_handshake(3)|SSL_do_handshake(3)>, 74L<SSL_CTX_new(3)|SSL_CTX_new(3)> 75 76=cut 77