SSL_accept(3)

NAME

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

SYNOPSIS

        #include <openssl/ssl.h>

        int SSL_accept(SSL *ssl);

DESCRIPTION

       SSL_accept() waits for a TLS/SSL client to initiate the TLS/SSL hand-
       shake.  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 non-blocking, 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 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.

RETURN VALUES

       The following return values can occur:

       0   The TLS/SSL handshake was not successful but was shut down con-
           trolled 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 connec-
           tion 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 of action
           is need to continue the operation for non-blocking 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(3), bio(3),
       SSL_set_connect_state(3), SSL_do_handshake(3), SSL_CTX_new(3)

1.0.2t                            2019-09-10                     SSL_accept(3)