Updated: 2022/Sep/29

Please read Privacy Policy. It's for your privacy.

SSL_set_fd(3)                       OpenSSL                      SSL_set_fd(3)



NAME
       SSL_set_fd, SSL_set_rfd, SSL_set_wfd - connect the SSL object with a
       file descriptor

LIBRARY
       libcrypto, -lcrypto

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>.



3.0.12                            2023-05-07                     SSL_set_fd(3)