get.c revision 1.6 
1/*	$OpenBSD: get.c,v 1.6 2004/04/14 20:37:28 henning Exp $ */
2
3/*
4 * Copyright (c) 1993-95 Mats O Jansson.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#ifndef LINT
28static const char rcsid[] =
29    "$OpenBSD: get.c,v 1.6 2004/04/14 20:37:28 henning Exp $";
30#endif
31
32#include <sys/types.h>
33#include "common/mopdef.h"
34
35u_char
36mopGetChar(u_char *pkt, int *index)
37{
38	u_char ret;
39
40	ret = pkt[*index];
41	*index = *index + 1;
42	return (ret);
43}
44
45u_short
46mopGetShort(u_char *pkt, int *index)
47{
48	u_short ret;
49
50	ret = pkt[*index] + pkt[*index+1]*256;
51	*index = *index + 2;
52	return (ret);
53}
54
55u_long
56mopGetLong(u_char *pkt, int *index)
57{
58	u_long ret;
59
60	ret = pkt[*index] + pkt[*index+1]*0x100 + pkt[*index+2]*0x10000 +
61	    pkt[*index+3]*0x1000000;
62	*index = *index + 4;
63	return (ret);
64}
65
66void
67mopGetMulti(u_char *pkt, int *index, u_char *dest, int size)
68{
69	int i;
70
71	for (i = 0; i < size; i++)
72		dest[i] = pkt[*index+i];
73	*index = *index + size;
74}
75
76int
77mopGetTrans(u_char *pkt, int trans)
78{
79	u_short	*ptype;
80
81	if (trans == 0) {
82		ptype = (u_short *)(pkt+12);
83		if (ntohs(*ptype) < 1600)
84			trans = TRANS_8023;
85		else
86			trans = TRANS_ETHER;
87	}
88	return (trans);
89}
90
91void
92mopGetHeader(u_char *pkt, int *index, u_char **dst, u_char **src,
93    u_short *proto, int *len, int trans)
94{
95	*dst = pkt;
96	*src = pkt + 6;
97	*index = *index + 12;
98
99	switch (trans) {
100	case TRANS_ETHER:
101		*proto = (u_short)(pkt[*index] * 256 + pkt[*index + 1]);
102		*index = *index + 2;
103		*len   = (int)(pkt[*index + 1] * 256 + pkt[*index]);
104		*index = *index + 2;
105		break;
106	case TRANS_8023:
107		*len   = (int)(pkt[*index] * 256 + pkt[*index + 1]);
108		*index = *index + 8;
109		*proto = (u_short)(pkt[*index] * 256 + pkt[*index + 1]);
110		*index = *index + 2;
111		break;
112	}
113}
114
115u_short
116mopGetLength(u_char *pkt, int trans)
117{
118	switch (trans) {
119	case TRANS_ETHER:
120		return (pkt[15] * 256 + pkt[14]);
121		break;
122	case TRANS_8023:
123		return (pkt[12] * 256 + pkt[13]);
124		break;
125	}
126	return (0);
127}
128