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dhcp 4.1 r7

    1: /* buffer.h
    2: 
    3:    Definitions for the object management API protocol buffering... */
    4: 
    5: /*
    6:  * Copyright (c) 2004,2009 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:  *   https://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:  * ``https://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: