include/sys/bufmod.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 1991, 1997-1998 by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 #ifndef _SYS_BUFMOD_H
  28 #define _SYS_BUFMOD_H
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include <sys/types.h>
  33 #include <sys/types32.h>
  34
  35 #ifdef  __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 /*
  40  * Definitions for the STREAMS Buffering module.
  41  *
  42  * The module gathers incoming (read-side) messages together into
  43  * "chunks" and passes completed chunks up to the next module in
  44  * line.  The gathering process is controlled by two ioctl-settable
  45  * parameters:
  46  *
  47  * timeout      The maximum delay after passing the previous chunk
  48  *              upward before passing the current one up, even if the
  49  *              chunk isn't full.  If the timeout value passed in is
  50  *              a null pointer, the timeout is infinite (as in the
  51  *              select system call); this is the default.
  52  * chunksize    The maximum size of a chunk of accumulated messages,
  53  *              unless a single message exceeds the chunksize, in
  54  *              which case it's passed up in a chunk containing only
  55  *              that message.  Note that a given message's size includes
  56  *              the length of any leading M_PROTO blocks it may have.
  57  *
  58  * There is one important side-effect: setting the timeout to zero
  59  * (polling) will force the chunksize to zero, regardless of its
  60  * previous setting.
  61  */
  62
  63 /*
  64  * Ioctls.
  65  */
  66 #define SBIOC   ('B' << 8)
  67 #define SBIOCSTIME      (SBIOC|1)       /* set timeout info */
  68 #define SBIOCGTIME      (SBIOC|2)       /* get timeout info */
  69 #define SBIOCCTIME      (SBIOC|3)       /* clear timeout */
  70 #define SBIOCSCHUNK     (SBIOC|4)       /* set chunksize */
  71 #define SBIOCGCHUNK     (SBIOC|5)       /* get chunksize */
  72 #define SBIOCSSNAP      (SBIOC|6)       /* set snapshot length */
  73 #define SBIOCGSNAP      (SBIOC|7)       /* get snapshot length */
  74 #define SBIOCSFLAGS     (SBIOC|8)       /* set buffering modes */
  75 #define SBIOCGFLAGS     (SBIOC|9)       /* get buffering modes */
  76
  77 /*
  78  * Default chunk size.
  79  */
  80 #define SB_DFLT_CHUNK   8192    /* arbitrary */
  81
  82 /*
  83  * buffering flags
  84  */
  85
  86 #define SB_SEND_ON_WRITE        1       /* return buffered read data on write */
  87 #define SB_NO_HEADER            2       /* don't add header structure to data */
  88 #define SB_NO_PROTO_CVT         4       /* don't convert proto to data */
  89 #define SB_DEFER_CHUNK          8       /* fast response time buffering */
  90 #define SB_NO_DROPS             16      /* Don't drop messages */
  91
  92 /*
  93  * buffering state
  94  */
  95 #define SB_FRCVD        1       /* first message in time window received */
  96
  97 /*
  98  * When adding a given message to an accumulating chunk, the module
  99  * first converts any leading M_PROTO data block to M_DATA.
 100  * It then constructs an sb_hdr (defined below), prepends it to
 101  * the message, and pads the result out to force its length to a
 102  * multiple of a machine-dependent alignment size guaranteed to be
 103  * at least sizeof (ulong_t).  It then adds the padded message to the
 104  * chunk.
 105  *
 106  * sb_origlen is the original length of the message after the M_PROTO => M_DATA
 107  * conversion, but before truncating or adding the header.
 108  *
 109  * sb_msglen is the length of the message after truncation, but before
 110  * adding the header.
 111  *
 112  * sb_totlen is the length of the message after truncation, and including
 113  * both the header itself and the trailing padding bytes.
 114  *
 115  * sb_drops is the cumulative number of messages dropped by the module
 116  * due to stream read-side flow control or resource exhaustion.
 117  *
 118  * sb_timestamp is the packet arrival time expressed as a 'struct timeval'.
 119  */
 120
 121 struct sb_hdr {
 122         uint_t  sbh_origlen;
 123         uint_t  sbh_msglen;
 124         uint_t  sbh_totlen;
 125         uint_t  sbh_drops;
 126 #if defined(_LP64) || defined(_I32LPx)
 127         struct  timeval32 sbh_timestamp;
 128 #else
 129         struct  timeval sbh_timestamp;
 130 #endif /* !_LP64 */
 131 };
 132
 133 #ifdef  __cplusplus
 134 }
 135 #endif
 136
 137 #endif  /* _SYS_BUFMOD_H */