1 /* $OpenBSD: get.c,v 1.7 2006/04/17 13:17:07 maja Exp $ */ 2 3 /* 4 * Copyright (c) 1993-2006 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 28 static const char rcsid[] = 29 "$OpenBSD: get.c,v 1.7 2006/04/17 13:17:07 maja Exp $"; 30 #endif 31 32 #include <sys/types.h> 33 #include "common/mopdef.h" 34 35 u_char 36 mopGetChar(u_char *pkt, int *idx) 37 { 38 u_char ret; 39 40 ret = pkt[*idx]; 41 *idx = *idx + 1; 42 return (ret); 43 } 44 45 u_short 46 mopGetShort(u_char *pkt, int *idx) 47 { 48 u_short ret; 49 50 ret = pkt[*idx] + pkt[*idx+1]*256; 51 *idx = *idx + 2; 52 return (ret); 53 } 54 55 u_short 56 mopGetNShort(u_char *pkt, int *idx) 57 { 58 u_short ret; 59 60 ret = pkt[*idx]*256 + pkt[*idx+1]; 61 *idx = *idx + 2; 62 return (ret); 63 } 64 65 u_long 66 mopGetLong(u_char *pkt, int *idx) 67 { 68 u_long ret; 69 70 ret = pkt[*idx] + pkt[*idx+1]*0x100 + pkt[*idx+2]*0x10000 + 71 pkt[*idx+3]*0x1000000; 72 *idx = *idx + 4; 73 return (ret); 74 } 75 76 void 77 mopGetMulti(u_char *pkt, int *idx, u_char *dest, int size) 78 { 79 int i; 80 81 for (i = 0; i < size; i++) 82 dest[i] = pkt[*idx+i]; 83 *idx = *idx + size; 84 } 85 86 int 87 mopGetTrans(u_char *pkt, int trans) 88 { 89 u_short ptype; 90 91 if (trans == 0) { 92 ptype = pkt[12]*256 + pkt[13]; 93 if (ptype < 1600) 94 trans = TRANS_8023; 95 else 96 trans = TRANS_ETHER; 97 } 98 return (trans); 99 } 100 101 void 102 mopGetHeader(u_char *pkt, int *idx, u_char **dst, u_char **src, 103 u_short *proto, int *len, int trans) 104 { 105 *dst = pkt; 106 *src = pkt + 6; 107 *idx = *idx + 12; 108 109 switch (trans) { 110 case TRANS_ETHER: 111 *proto = mopGetNShort(pkt, idx); 112 *len = (int)mopGetShort(pkt, idx); 113 break; 114 case TRANS_8023: 115 *len = (int)mopGetNShort(pkt, idx); 116 *idx = *idx + 6; 117 *proto = mopGetNShort(pkt, idx); 118 break; 119 } 120 } 121 122 u_short 123 mopGetLength(u_char *pkt, int trans) 124 { 125 switch (trans) { 126 case TRANS_ETHER: 127 return (pkt[14] + pkt[15]*256); 128 case TRANS_8023: 129 return (pkt[12]*256 + pkt[13]); 130 } 131 return (0); 132 } 133