SSL_ACCEPT(3) BSD Library Functions Manual SSL_ACCEPT(3)NAMESSL_accept — wait for a TLS/SSL client to initiate a TLS/SSL handshake
SYNOPSIS
#include <openssl/ssl.h>
int
SSL_accept(SSL *ssl);
DESCRIPTIONSSL_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 object 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 con‐
tinue the handshake, indicating the problem by the return value −1. In
this case a call to SSL_get_error(3) 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 underly‐
ing BIO. When using a non-blocking socket, nothing is to be done, but
select(2) 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(3) with the return value ret to find out the rea‐
son.
1 The TLS/SSL handshake was successfully completed, and 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 of
action is need to continue the operation for non-blocking BIOs.
Call SSL_get_error(3) with the return value ret to find out the
reason.
SEE ALSObio(3), ssl(3), SSL_connect(3), SSL_CTX_new(3), SSL_do_handshake(3),
SSL_get_error(3), SSL_set_connect_state(3), SSL_shutdown(3)BSD April 29, 2024 BSD
