1*4724848cSchristos=pod 2*4724848cSchristos 3*4724848cSchristos=head1 NAME 4*4724848cSchristos 5*4724848cSchristosSSL_accept - wait for a TLS/SSL client to initiate a TLS/SSL handshake 6*4724848cSchristos 7*4724848cSchristos=head1 SYNOPSIS 8*4724848cSchristos 9*4724848cSchristos #include <openssl/ssl.h> 10*4724848cSchristos 11*4724848cSchristos int SSL_accept(SSL *ssl); 12*4724848cSchristos 13*4724848cSchristos=head1 DESCRIPTION 14*4724848cSchristos 15*4724848cSchristosSSL_accept() waits for a TLS/SSL client to initiate the TLS/SSL handshake. 16*4724848cSchristosThe communication channel must already have been set and assigned to the 17*4724848cSchristosB<ssl> by setting an underlying B<BIO>. 18*4724848cSchristos 19*4724848cSchristos=head1 NOTES 20*4724848cSchristos 21*4724848cSchristosThe behaviour of SSL_accept() depends on the underlying BIO. 22*4724848cSchristos 23*4724848cSchristosIf the underlying BIO is B<blocking>, SSL_accept() will only return once the 24*4724848cSchristoshandshake has been finished or an error occurred. 25*4724848cSchristos 26*4724848cSchristosIf the underlying BIO is B<nonblocking>, SSL_accept() will also return 27*4724848cSchristoswhen the underlying BIO could not satisfy the needs of SSL_accept() 28*4724848cSchristosto continue the handshake, indicating the problem by the return value -1. 29*4724848cSchristosIn this case a call to SSL_get_error() with the 30*4724848cSchristosreturn value of SSL_accept() will yield B<SSL_ERROR_WANT_READ> or 31*4724848cSchristosB<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after 32*4724848cSchristostaking appropriate action to satisfy the needs of SSL_accept(). 33*4724848cSchristosThe action depends on the underlying BIO. When using a nonblocking socket, 34*4724848cSchristosnothing is to be done, but select() can be used to check for the required 35*4724848cSchristoscondition. When using a buffering BIO, like a BIO pair, data must be written 36*4724848cSchristosinto or retrieved out of the BIO before being able to continue. 37*4724848cSchristos 38*4724848cSchristos=head1 RETURN VALUES 39*4724848cSchristos 40*4724848cSchristosThe following return values can occur: 41*4724848cSchristos 42*4724848cSchristos=over 4 43*4724848cSchristos 44*4724848cSchristos=item Z<>0 45*4724848cSchristos 46*4724848cSchristosThe TLS/SSL handshake was not successful but was shut down controlled and 47*4724848cSchristosby the specifications of the TLS/SSL protocol. Call SSL_get_error() with the 48*4724848cSchristosreturn value B<ret> to find out the reason. 49*4724848cSchristos 50*4724848cSchristos=item Z<>1 51*4724848cSchristos 52*4724848cSchristosThe TLS/SSL handshake was successfully completed, a TLS/SSL connection has been 53*4724848cSchristosestablished. 54*4724848cSchristos 55*4724848cSchristos=item E<lt>0 56*4724848cSchristos 57*4724848cSchristosThe TLS/SSL handshake was not successful because a fatal error occurred either 58*4724848cSchristosat the protocol level or a connection failure occurred. The shutdown was 59*4724848cSchristosnot clean. It can also occur if action is needed to continue the operation 60*4724848cSchristosfor nonblocking BIOs. Call SSL_get_error() with the return value B<ret> 61*4724848cSchristosto find out the reason. 62*4724848cSchristos 63*4724848cSchristos=back 64*4724848cSchristos 65*4724848cSchristos=head1 SEE ALSO 66*4724848cSchristos 67*4724848cSchristosL<SSL_get_error(3)>, L<SSL_connect(3)>, 68*4724848cSchristosL<SSL_shutdown(3)>, L<ssl(7)>, L<bio(7)>, 69*4724848cSchristosL<SSL_set_connect_state(3)>, 70*4724848cSchristosL<SSL_do_handshake(3)>, 71*4724848cSchristosL<SSL_CTX_new(3)> 72*4724848cSchristos 73*4724848cSchristos=head1 COPYRIGHT 74*4724848cSchristos 75*4724848cSchristosCopyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 76*4724848cSchristos 77*4724848cSchristosLicensed under the OpenSSL license (the "License"). You may not use 78*4724848cSchristosthis file except in compliance with the License. You can obtain a copy 79*4724848cSchristosin the file LICENSE in the source distribution or at 80*4724848cSchristosL<https://www.openssl.org/source/license.html>. 81*4724848cSchristos 82*4724848cSchristos=cut 83