1 /* $OpenBSD: get.c,v 1.8 2009/10/27 23:59:52 deraadt 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 #include <sys/types.h> 28 #include "common/mopdef.h" 29 30 u_char 31 mopGetChar(u_char *pkt, int *idx) 32 { 33 u_char ret; 34 35 ret = pkt[*idx]; 36 *idx = *idx + 1; 37 return (ret); 38 } 39 40 u_short 41 mopGetShort(u_char *pkt, int *idx) 42 { 43 u_short ret; 44 45 ret = pkt[*idx] + pkt[*idx+1]*256; 46 *idx = *idx + 2; 47 return (ret); 48 } 49 50 u_short 51 mopGetNShort(u_char *pkt, int *idx) 52 { 53 u_short ret; 54 55 ret = pkt[*idx]*256 + pkt[*idx+1]; 56 *idx = *idx + 2; 57 return (ret); 58 } 59 60 u_long 61 mopGetLong(u_char *pkt, int *idx) 62 { 63 u_long ret; 64 65 ret = pkt[*idx] + pkt[*idx+1]*0x100 + pkt[*idx+2]*0x10000 + 66 pkt[*idx+3]*0x1000000; 67 *idx = *idx + 4; 68 return (ret); 69 } 70 71 void 72 mopGetMulti(u_char *pkt, int *idx, u_char *dest, int size) 73 { 74 int i; 75 76 for (i = 0; i < size; i++) 77 dest[i] = pkt[*idx+i]; 78 *idx = *idx + size; 79 } 80 81 int 82 mopGetTrans(u_char *pkt, int trans) 83 { 84 u_short ptype; 85 86 if (trans == 0) { 87 ptype = pkt[12]*256 + pkt[13]; 88 if (ptype < 1600) 89 trans = TRANS_8023; 90 else 91 trans = TRANS_ETHER; 92 } 93 return (trans); 94 } 95 96 void 97 mopGetHeader(u_char *pkt, int *idx, u_char **dst, u_char **src, 98 u_short *proto, int *len, int trans) 99 { 100 *dst = pkt; 101 *src = pkt + 6; 102 *idx = *idx + 12; 103 104 switch (trans) { 105 case TRANS_ETHER: 106 *proto = mopGetNShort(pkt, idx); 107 *len = (int)mopGetShort(pkt, idx); 108 break; 109 case TRANS_8023: 110 *len = (int)mopGetNShort(pkt, idx); 111 *idx = *idx + 6; 112 *proto = mopGetNShort(pkt, idx); 113 break; 114 } 115 } 116 117 u_short 118 mopGetLength(u_char *pkt, int trans) 119 { 120 switch (trans) { 121 case TRANS_ETHER: 122 return (pkt[14] + pkt[15]*256); 123 case TRANS_8023: 124 return (pkt[12]*256 + pkt[13]); 125 } 126 return (0); 127 } 128