workbench/network/stacks/AROSTCP/dhcp/includes/omapip/buffer.h

   1 /* buffer.h
   2
   3    Definitions for the object management API protocol buffering... */
   4
   5 /*
   6  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   7  * Copyright (c) 1996-2003 by Internet Software Consortium
   8  *
   9  * Permission to use, copy, modify, and distribute this software for any
  10  * purpose with or without fee is hereby granted, provided that the above
  11  * copyright notice and this permission notice appear in all copies.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  19  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20  *
  21  *   Internet Systems Consortium, Inc.
  22  *   950 Charter Street
  23  *   Redwood City, CA 94063
  24  *   <info@isc.org>
  25  *   http://www.isc.org/
  26  *
  27  * This software has been written for Internet Systems Consortium
  28  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
  29  * To learn more about Internet Systems Consortium, see
  30  * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
  31  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
  32  * ``http://www.nominum.com''.
  33  */
  34
  35 /* OMAPI buffers are ring buffers, which means that the beginning of the
  36    buffer and the end of the buffer chase each other around.   As long as
  37    the tail never catches up to the head, there's room in the buffer for
  38    data.
  39
  40         - If the tail and the head are equal, the buffer is empty.
  41
  42         - If the tail is less than the head, the contents of the buffer
  43           are the bytes from the head to the end of buffer, and in addition,
  44           the bytes between the beginning of the buffer and the tail, not
  45           including the byte addressed by the tail.
  46
  47         - If the tail is greater than the head, then the buffer contains
  48           valid bytes starting with the byte addressed by the head, and
  49           ending with the byte before the byte addressed by the tail.
  50
  51    There will always be at least one byte of waste, because the tail can't
  52    increase so that it's equal to the head (that would represent an empty
  53    buffer. */
  54 #define OMAPI_BUF_SIZE 4048
  55 typedef struct _omapi_buffer {
  56         struct _omapi_buffer *next;     /* Buffers can be chained. */
  57         u_int32_t refcnt;               /* Buffers are reference counted. */
  58         u_int16_t head, tail;           /* Buffers are organized in a ring. */
  59         char buf [OMAPI_BUF_SIZE];      /* The actual buffer is included in
  60                                            the buffer data structure. */
  61 } omapi_buffer_t;
  62
  63 #define BUFFER_BYTES_FREE(x)    \
  64         ((x) -> tail > (x) -> head \
  65           ? sizeof ((x) -> buf) - ((x) -> tail - (x) -> head) \
  66           : (x) -> head - (x) -> tail)
  67
  68 #define BYTES_IN_BUFFER(x)      \
  69         ((x) -> tail > (x) -> head \
  70          ? (x) -> tail - (x) -> head - 1 \
  71          : sizeof ((x) -> buf) - ((x) -> head - (x) -> tail) - 1)
  72
  73 isc_result_t omapi_connection_require (omapi_object_t *, unsigned);
  74 isc_result_t omapi_connection_copyout (unsigned char *,
  75                                        omapi_object_t *, unsigned);
  76 isc_result_t omapi_connection_copyin (omapi_object_t *,
  77                                       const unsigned char *, unsigned);
  78 isc_result_t omapi_connection_flush (omapi_object_t *);
  79 isc_result_t omapi_connection_get_uint32 (omapi_object_t *, u_int32_t *);
  80 isc_result_t omapi_connection_put_uint32 (omapi_object_t *, u_int32_t);
  81 isc_result_t omapi_connection_get_uint16 (omapi_object_t *, u_int16_t *);
  82 isc_result_t omapi_connection_put_uint16 (omapi_object_t *, u_int32_t);
  83