/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1991, 1997-1998 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#ifndef _SYS_BUFMOD_H
#define _SYS_BUFMOD_H

#include <sys/types.h>
#include <sys/types32.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * Definitions for the STREAMS Buffering module.
 *
 * The module gathers incoming (read-side) messages together into
 * "chunks" and passes completed chunks up to the next module in
 * line.  The gathering process is controlled by two ioctl-settable
 * parameters:
 *
 * timeout      The maximum delay after passing the previous chunk
 *              upward before passing the current one up, even if the
 *              chunk isn't full.  If the timeout value passed in is
 *              a null pointer, the timeout is infinite (as in the
 *              select system call); this is the default.
 * chunksize    The maximum size of a chunk of accumulated messages,
 *              unless a single message exceeds the chunksize, in
 *              which case it's passed up in a chunk containing only
 *              that message.  Note that a given message's size includes
 *              the length of any leading M_PROTO blocks it may have.
 *
 * There is one important side-effect: setting the timeout to zero
 * (polling) will force the chunksize to zero, regardless of its
 * previous setting.
 */

/*
 * Ioctls.
 */
#define SBIOC   ('B' << 8)
#define SBIOCSTIME      (SBIOC|1)       /* set timeout info */
#define SBIOCGTIME      (SBIOC|2)       /* get timeout info */
#define SBIOCCTIME      (SBIOC|3)       /* clear timeout */
#define SBIOCSCHUNK     (SBIOC|4)       /* set chunksize */
#define SBIOCGCHUNK     (SBIOC|5)       /* get chunksize */
#define SBIOCSSNAP      (SBIOC|6)       /* set snapshot length */
#define SBIOCGSNAP      (SBIOC|7)       /* get snapshot length */
#define SBIOCSFLAGS     (SBIOC|8)       /* set buffering modes */
#define SBIOCGFLAGS     (SBIOC|9)       /* get buffering modes */

/*
 * Default chunk size.
 */
#define SB_DFLT_CHUNK   8192    /* arbitrary */

/*
 * buffering flags
 */

#define SB_SEND_ON_WRITE        1       /* return buffered read data on write */
#define SB_NO_HEADER            2       /* don't add header structure to data */
#define SB_NO_PROTO_CVT         4       /* don't convert proto to data */
#define SB_DEFER_CHUNK          8       /* fast response time buffering */
#define SB_NO_DROPS             16      /* Don't drop messages */

/*
 * buffering state
 */
#define SB_FRCVD        1       /* first message in time window received */

/*
 * When adding a given message to an accumulating chunk, the module
 * first converts any leading M_PROTO data block to M_DATA.
 * It then constructs an sb_hdr (defined below), prepends it to
 * the message, and pads the result out to force its length to a
 * multiple of a machine-dependent alignment size guaranteed to be
 * at least sizeof (ulong_t).  It then adds the padded message to the
 * chunk.
 *
 * sb_origlen is the original length of the message after the M_PROTO => M_DATA
 * conversion, but before truncating or adding the header.
 *
 * sb_msglen is the length of the message after truncation, but before
 * adding the header.
 *
 * sb_totlen is the length of the message after truncation, and including
 * both the header itself and the trailing padding bytes.
 *
 * sb_drops is the cumulative number of messages dropped by the module
 * due to stream read-side flow control or resource exhaustion.
 *
 * sb_timestamp is the packet arrival time expressed as a 'struct timeval'.
 */

struct sb_hdr {
        uint_t  sbh_origlen;
        uint_t  sbh_msglen;
        uint_t  sbh_totlen;
        uint_t  sbh_drops;
#if defined(_LP64)
        struct  timeval32 sbh_timestamp;
#else
        struct  timeval sbh_timestamp;
#endif /* !_LP64 */
};

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_BUFMOD_H */