FreeBSD manual
download PDF document: SSL_set_wfd.3.pdf
SSL_SET_FD(3ossl) OpenSSL SSL_SET_FD(3ossl)
NAME
SSL_set_fd, SSL_set_rfd, SSL_set_wfd - connect the SSL object with a
file descriptor
SYNOPSIS
#include <openssl/ssl.h>
int SSL_set_fd(SSL *ssl, int fd);
int SSL_set_rfd(SSL *ssl, int fd);
int SSL_set_wfd(SSL *ssl, int fd);
DESCRIPTION
SSL_set_fd() sets the file descriptor fd as the input/output facility
for the TLS/SSL (encrypted) side of ssl. fd will typically be the
socket file descriptor of a network connection.
When performing the operation, a socket BIO is automatically created to
interface between the ssl and fd. The BIO and hence the SSL engine
inherit the behaviour of fd. If fd is nonblocking, the ssl will also
have nonblocking behaviour.
If there was already a BIO connected to ssl, BIO_free() will be called
(for both the reading and writing side, if different).
SSL_set_rfd() and SSL_set_wfd() perform the respective action, but only
for the read channel or the write channel, which can be set
independently.
RETURN VALUES
The following return values can occur:
0 The operation failed. Check the error stack to find out why.
1 The operation succeeded.
NOTES
On Windows, a socket handle is a 64-bit data type (UINT_PTR), which
leads to a compiler warning (conversion from 'SOCKET' to 'int',
possible loss of data) when passing the socket handle to SSL_set_*fd().
For the time being, this warning can safely be ignored, because
although the Microsoft documentation claims that the upper limit is
INVALID_SOCKET-1 (2^64 - 2), in practice the current socket()
implementation returns an index into the kernel handle table, the size
of which is limited to 2^24.
SEE ALSO
SSL_get_fd(3), SSL_set_bio(3), SSL_connect(3), SSL_accept(3),
SSL_shutdown(3), ssl(7) , bio(7)
COPYRIGHT
Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.