SSL_accept - Wait for a TLS/SSL client to initiate a
TLS/SSL handshake
#include <openssl/ssl.h>
int SSL_accept(
SSL *ssl );
The SSL_accept() function 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.
The behavior of the SSL_accept() function depends on the
underlying BIO.
If the underlying BIO is blocking, the SSL_accept() function
will only return once the handshake has been finished
or an error occurred, except for Server Gated Cryptography
(SGC). For SGC, the SSL_accept() function might return
with -1, but the SSL_get_error() function will yield
SSL_ERROR_WANT_READ/WRITE and SSL_accept() should be
called again.
If the underlying BIO is non-blocking, the SSL_accept()
function will also return when the underlying BIO could
not satisfy the needs of the SSL_accept() function to continue
the handshake. In this case a call to the
SSL_get_error() function 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 the select() function 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.
The following return values can occur: The TLS/SSL handshake
was successfully completed, a TLS/SSL connection has
been established. 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 the reason. 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 non-blocking
BIOs. Call the SSL_get_error() function with the
return value ret to find the reason.
Functions: 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)
SSL_accept(3)
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