=pod

=head1 NAME

SSL_get_stream_id, SSL_get_stream_type, SSL_STREAM_TYPE_NONE,
SSL_STREAM_TYPE_READ, SSL_STREAM_TYPE_WRITE, SSL_STREAM_TYPE_BIDI,
SSL_is_stream_local - get QUIC stream ID and stream type information

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 uint64_t SSL_get_stream_id(SSL *ssl);

 #define SSL_STREAM_TYPE_NONE
 #define SSL_STREAM_TYPE_BIDI
 #define SSL_STREAM_TYPE_READ
 #define SSL_STREAM_TYPE_WRITE
 int SSL_get_stream_type(SSL *ssl);

 int SSL_is_stream_local(SSL *ssl);

=head1 DESCRIPTION

The SSL_get_stream_id() function returns the QUIC stream ID for a QUIC stream
SSL object, or for a QUIC connection SSL object which has a default stream
attached.

The SSL_get_stream_type() function identifies what operations can be performed
on the stream, and returns one of the following values:

=over 4

=item B<SSL_STREAM_TYPE_NONE>

The SSL object is a QUIC connection SSL object without a default stream
attached.

=item B<SSL_STREAM_TYPE_BIDI>

The SSL object is a non-QUIC SSL object, or is a QUIC stream object (or QUIC
connection SSL object with a default stream attached), and that stream is a
bidirectional QUIC stream.

=item B<SSL_STREAM_TYPE_READ>

The SSL object is a QUIC stream object (or QUIC connection SSL object with a
default stream attached), and that stream is a unidirectional QUIC stream which
was initiated by the remote peer; thus, it can be read from, but not written to.

=item B<SSL_STREAM_TYPE_WRITE>

The SSL object is a QUIC stream object (or QUIC connection SSL object with a
default stream attached), and that stream is a unidirectional QUIC stream which
was initiated by the local application; thus, it can be written to, but not read
from.

=back

The SSL_is_stream_local() function determines whether a stream was locally
created.

=head1 NOTES

While QUICv1 assigns specific meaning to the low two bits of a QUIC stream ID,
QUIC stream IDs in future versions of QUIC are not required to have the same
semantics. Do not determine stream properties using these bits. Instead, use
SSL_get_stream_type() to determine the stream type and SSL_get_stream_is_local()
to determine the stream initiator.

The SSL_get_stream_type() identifies the type of a QUIC stream based on its
identity, and does not indicate whether an operation can currently be
successfully performed on a stream. For example, you might locally initiate a
unidirectional stream, write to it, and then conclude the stream using
L<SSL_stream_conclude(3)>, meaning that it can no longer be written to, but
SSL_get_stream_type() would still return B<SSL_STREAM_TYPE_WRITE>. The value
returned by SSL_get_stream_type() does not vary over the lifespan of a stream.

=head1 RETURN VALUES

SSL_get_stream_id() returns a QUIC stream ID, or B<UINT64_MAX> if called on an
SSL object which is not a QUIC SSL object, or if called on a QUIC connection SSL
object without a default stream attached. Note that valid QUIC stream IDs are
always below 2**62.

SSL_get_stream_type() returns one of the B<SSL_STREAM_TYPE> values.

SSL_is_stream_local() returns 1 if called on a QUIC stream SSL object which
represents a stream which was locally initiated. It returns 0 if called on a
QUIC stream SSL object which represents a stream which was remotely initiated by
a peer, and -1 if called on any other kind of SSL object.

=head1 SEE ALSO

L<SSL_new_stream(3)>, L<SSL_accept_stream(3)>

=head1 HISTORY

These functions were added in OpenSSL 3.2.

=head1 COPYRIGHT

Copyright 2002-2023 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
L<https://www.openssl.org/source/license.html>.

=cut
