Updated: 2021/Apr/14


SSL_accept(3)                       OpenSSL                      SSL_accept(3)



NAME
       SSL_accept - wait for a TLS/SSL client to initiate a TLS/SSL handshake

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/ssl.h>

        int SSL_accept(SSL *ssl);

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

NOTES
       The behaviour of SSL_accept() depends on the underlying BIO.

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

       If the underlying BIO is nonblocking, SSL_accept() will also return
       when the underlying BIO could not satisfy the needs of SSL_accept() 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_accept() will yield SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE.
       The calling process then must repeat the call after taking appropriate
       action to satisfy the needs of SSL_accept().  The action depends on the
       underlying BIO. When using a nonblocking 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.

RETURN VALUES
       The following return values can occur:

       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 ret to find out the reason.

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

       <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 if action
           is needed to continue the operation for nonblocking BIOs. Call
           SSL_get_error() with the return value ret to find out the reason.

SEE ALSO
       SSL_get_error(3), SSL_connect(3), SSL_shutdown(3), ssl(7), bio(7),
       SSL_set_connect_state(3), SSL_do_handshake(3), SSL_CTX_new(3)

COPYRIGHT
       Copyright 2000-2020 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
       <https://www.openssl.org/source/license.html>.



1.1.1i                            2020-12-10                     SSL_accept(3)