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
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, except for SGC (Server Gated Cryptography). For
SGC, SSL_accept() may return with -1, but SSL_get_error() will yield
SSL_ERROR_WANT_READ/WRITE and
SSL_accept() should be called again.
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:
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 out 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 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.
