ddp.h revision 15885 
1/*
2 * Copyright (c) 1990,1991 Regents of The University of Michigan.
3 * All Rights Reserved.
4 *
5 * Permission to use, copy, modify, and distribute this software and
6 * its documentation for any purpose and without fee is hereby granted,
7 * provided that the above copyright notice appears in all copies and
8 * that both that copyright notice and this permission notice appear
9 * in supporting documentation, and that the name of The University
10 * of Michigan not be used in advertising or publicity pertaining to
11 * distribution of the software without specific, written prior
12 * permission. This software is supplied as is without expressed or
13 * implied warranties of any kind.
14 *
15 *	Research Systems Unix Group
16 *	The University of Michigan
17 *	c/o Mike Clark
18 *	535 W. William Street
19 *	Ann Arbor, Michigan
20 *	+1-313-763-0525
21 *	netatalk@itd.umich.edu
22 */
23#ifndef _NETATALK_DDP_H_
24#define _NETATALK_DDP_H_ 1
25
26/*
27 * <-1byte(8bits) ->
28 * +---------------+
29 * | 0 | hopc  |len|
30 * +---------------+
31 * | len (cont)    |
32 * +---------------+
33 * |               |
34 * +- DDP csum    -+
35 * |               |
36 * +---------------+
37 * |               |
38 * +- Dest NET    -+
39 * |               |
40 * +---------------+
41 * |               |
42 * +- Src NET     -+
43 * |               |
44 * +---------------+
45 * | Dest NODE     |
46 * +---------------+
47 * | Src NODE      |
48 * +---------------+
49 * | Dest PORT     |
50 * +---------------+
51 * | Src PORT      |
52 * +---------------+
53 *
54 * On Apples, there is also a ddp_type field, after src_port. However,
55 * under this unix implementation, user level processes need to be able
56 * to set the ddp_type. In later revisions, the ddp_type may only be
57 * available in a raw_appletalk interface.
58 */
59
60struct elaphdr {
61    u_char	el_dnode;
62    u_char	el_snode;
63    u_char	el_type;
64};
65
66#define	SZ_ELAPHDR	3
67
68#define ELAP_DDPSHORT	0x01
69#define ELAP_DDPEXTEND	0x02
70
71/*
72 * Extended DDP header. Includes sickness for dealing with arbitrary
73 * bitfields on a little-endian arch.
74 */
75struct ddpehdr {
76    union {
77	struct {
78#if BYTE_ORDER == BIG_ENDIAN
79    unsigned		dub_pad:2;
80    unsigned		dub_hops:4;
81    unsigned		dub_len:10;
82    unsigned		dub_sum:16;
83#endif
84#if BYTE_ORDER == LITTLE_ENDIAN
85    unsigned		dub_sum:16;
86    unsigned		dub_len:10;
87    unsigned		dub_hops:4;
88    unsigned		dub_pad:2;
89#endif
90	} du_bits;
91	unsigned	du_bytes;
92    } deh_u;
93#define deh_pad		deh_u.du_bits.dub_pad
94#define deh_hops	deh_u.du_bits.dub_hops
95#define deh_len		deh_u.du_bits.dub_len
96#define deh_sum		deh_u.du_bits.dub_sum
97#define deh_bytes	deh_u.du_bytes
98    u_short		deh_dnet;
99    u_short		deh_snet;
100    u_char		deh_dnode;
101    u_char		deh_snode;
102    u_char		deh_dport;
103    u_char		deh_sport;
104};
105
106#define DDP_MAXHOPS	15
107
108struct ddpshdr {
109    union {
110	struct {
111#if BYTE_ORDER == BIG_ENDIAN
112    unsigned		dub_pad:6;
113    unsigned		dub_len:10;
114    unsigned		dub_dport:8;
115    unsigned		dub_sport:8;
116#endif
117#if BYTE_ORDER == LITTLE_ENDIAN
118    unsigned		dub_sport:8;
119    unsigned		dub_dport:8;
120    unsigned		dub_len:10;
121    unsigned		dub_pad:6;
122#endif
123	} du_bits;
124	unsigned	du_bytes;
125    } dsh_u;
126#define dsh_pad		dsh_u.du_bits.dub_pad
127#define dsh_len		dsh_u.du_bits.dub_len
128#define dsh_dport	dsh_u.du_bits.dub_dport
129#define dsh_sport	dsh_u.du_bits.dub_sport
130#define dsh_bytes	dsh_u.du_bytes
131};
132
133#endif /* _NETATALK_DDP_H_ */
134