1=pod 2 3=head1 NAME 4 5SSL_set_fd, SSL_set_rfd, SSL_set_wfd - connect the SSL object with a file descriptor 6 7=head1 SYNOPSIS 8 9 #include <openssl/ssl.h> 10 11 int SSL_set_fd(SSL *ssl, int fd); 12 int SSL_set_rfd(SSL *ssl, int fd); 13 int SSL_set_wfd(SSL *ssl, int fd); 14 15=head1 DESCRIPTION 16 17SSL_set_fd() sets the file descriptor B<fd> as the input/output facility 18for the TLS/SSL (encrypted) side of B<ssl>. B<fd> will typically be the 19socket file descriptor of a network connection. 20 21When performing the operation, a B<socket BIO> is automatically created to 22interface between the B<ssl> and B<fd>. The BIO and hence the SSL engine 23inherit the behaviour of B<fd>. If B<fd> is nonblocking, the B<ssl> will 24also have nonblocking behaviour. 25 26When used on a QUIC connection SSL object, a B<datagram BIO> is automatically 27created instead of a B<socket BIO>. These functions fail if called 28on a QUIC stream SSL object. 29 30If there was already a BIO connected to B<ssl>, BIO_free() will be called 31(for both the reading and writing side, if different). 32 33SSL_set_rfd() and SSL_set_wfd() perform the respective action, but only 34for the read channel or the write channel, which can be set independently. 35 36=head1 RETURN VALUES 37 38The following return values can occur: 39 40=over 4 41 42=item Z<>0 43 44The operation failed. Check the error stack to find out why. 45 46=item Z<>1 47 48The operation succeeded. 49 50=back 51 52=head1 NOTES 53 54On Windows, a socket handle is a 64-bit data type (UINT_PTR), which leads to a 55compiler warning (conversion from 'SOCKET' to 'int', possible loss of data) when 56passing the socket handle to SSL_set_*fd(). For the time being, this warning can 57safely be ignored, because although the Microsoft documentation claims that the 58upper limit is INVALID_SOCKET-1 (2^64 - 2), in practice the current socket() 59implementation returns an index into the kernel handle table, the size of which 60is limited to 2^24. 61 62 63=head1 SEE ALSO 64 65L<SSL_get_fd(3)>, L<SSL_set_bio(3)>, 66L<SSL_connect(3)>, L<SSL_accept(3)>, 67L<SSL_shutdown(3)>, L<ssl(7)> , L<bio(7)> 68 69=head1 COPYRIGHT 70 71Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. 72 73Licensed under the Apache License 2.0 (the "License"). You may not use 74this file except in compliance with the License. You can obtain a copy 75in the file LICENSE in the source distribution or at 76L<https://www.openssl.org/source/license.html>. 77 78=cut 79
