| 1 | /*
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| 2 | * TAP-Win32 -- A kernel driver to provide virtual tap device functionality
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| 3 | * on Windows. Originally derived from the CIPE-Win32
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| 4 | * project by Damion K. Wilson, with extensive modifications by
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| 5 | * James Yonan.
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| 6 | *
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| 7 | * All source code which derives from the CIPE-Win32 project is
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| 8 | * Copyright (C) Damion K. Wilson, 2003, and is released under the
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| 9 | * GPL version 2 (see below).
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| 10 | *
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| 11 | * All other source code is Copyright (C) 2002-2005 OpenVPN Solutions LLC,
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| 12 | * and is released under the GPL version 2 (see below).
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| 13 | *
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| 14 | * This program is free software; you can redistribute it and/or modify
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| 15 | * it under the terms of the GNU General Public License version 2
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| 16 | * as published by the Free Software Foundation.
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| 17 | *
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| 18 | * This program is distributed in the hope that it will be useful,
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| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 21 | * GNU General Public License for more details.
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| 22 | *
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| 23 | * You should have received a copy of the GNU General Public License
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| 24 | * along with this program (see the file COPYING included with this
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| 25 | * distribution); if not, write to the Free Software Foundation, Inc.,
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| 26 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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| 27 | */
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| 28 |
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| 29 | #include "macinfo.h"
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| 30 |
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| 31 | int
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| 32 | HexStringToDecimalInt (const int p_Character)
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| 33 | {
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| 34 | int l_Value = 0;
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| 35 |
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| 36 | if (p_Character >= 'A' && p_Character <= 'F')
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| 37 | l_Value = (p_Character - 'A') + 10;
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| 38 | else if (p_Character >= 'a' && p_Character <= 'f')
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| 39 | l_Value = (p_Character - 'a') + 10;
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| 40 | else if (p_Character >= '0' && p_Character <= '9')
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| 41 | l_Value = p_Character - '0';
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| 42 |
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| 43 | return l_Value;
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| 44 | }
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| 45 |
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| 46 | BOOLEAN
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| 47 | ParseMAC (MACADDR dest, const char *src)
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| 48 | {
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| 49 | int c;
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| 50 | int mac_index = 0;
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| 51 | BOOLEAN high_digit = FALSE;
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| 52 | int delim_action = 1;
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| 53 |
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| 54 | MYASSERT (src);
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| 55 | MYASSERT (dest);
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| 56 |
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| 57 | CLEAR_MAC (dest);
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| 58 |
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| 59 | while (c = *src++)
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| 60 | {
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| 61 | if (IsMacDelimiter (c))
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| 62 | {
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| 63 | mac_index += delim_action;
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| 64 | high_digit = FALSE;
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| 65 | delim_action = 1;
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| 66 | }
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| 67 | else if (IsHexDigit (c))
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| 68 | {
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| 69 | const int digit = HexStringToDecimalInt (c);
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| 70 | if (mac_index < sizeof (MACADDR))
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| 71 | {
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| 72 | if (!high_digit)
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| 73 | {
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| 74 | dest[mac_index] = (char)(digit);
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| 75 | high_digit = TRUE;
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| 76 | delim_action = 1;
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| 77 | }
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| 78 | else
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| 79 | {
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| 80 | dest[mac_index] = (char)(dest[mac_index] * 16 + digit);
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| 81 | ++mac_index;
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| 82 | high_digit = FALSE;
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| 83 | delim_action = 0;
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| 84 | }
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| 85 | }
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| 86 | else
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| 87 | return FALSE;
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| 88 | }
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| 89 | else
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| 90 | return FALSE;
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| 91 | }
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| 92 |
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| 93 | return (mac_index + delim_action) >= sizeof (MACADDR);
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| 94 | }
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| 95 |
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| 96 | /*
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| 97 | * Generate a MAC using the GUID in the adapter name.
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| 98 | *
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| 99 | * The mac is constructed as 00:FF:xx:xx:xx:xx where
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| 100 | * the Xs are taken from the first 32 bits of the GUID in the
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| 101 | * adapter name. This is similar to the Linux 2.4 tap MAC
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| 102 | * generator, except linux uses 32 random bits for the Xs.
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| 103 | *
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| 104 | * In general, this solution is reasonable for most
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| 105 | * applications except for very large bridged TAP networks,
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| 106 | * where the probability of address collisions becomes more
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| 107 | * than infintesimal.
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| 108 | *
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| 109 | * Using the well-known "birthday paradox", on a 1000 node
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| 110 | * network the probability of collision would be
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| 111 | * 0.000116292153. On a 10,000 node network, the probability
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| 112 | * of collision would be 0.01157288998621678766.
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| 113 | */
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| 114 |
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| 115 | VOID GenerateRandomMac (MACADDR mac, const unsigned char *adapter_name)
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| 116 | {
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| 117 | unsigned const char *cp = adapter_name;
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| 118 | unsigned char c;
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| 119 | unsigned int i = 2;
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| 120 | unsigned int byte = 0;
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| 121 | int brace = 0;
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| 122 | int state = 0;
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| 123 |
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| 124 | CLEAR_MAC (mac);
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| 125 |
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| 126 | mac[0] = 0x00;
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| 127 | mac[1] = 0xFF;
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| 128 |
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| 129 | while (c = *cp++)
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| 130 | {
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| 131 | if (i >= sizeof (MACADDR))
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| 132 | break;
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| 133 | if (c == '{')
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| 134 | brace = 1;
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| 135 | if (IsHexDigit (c) && brace)
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| 136 | {
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| 137 | const unsigned int digit = HexStringToDecimalInt (c);
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| 138 | if (state)
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| 139 | {
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| 140 | byte <<= 4;
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| 141 | byte |= digit;
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| 142 | mac[i++] = (unsigned char) byte;
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| 143 | state = 0;
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| 144 | }
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| 145 | else
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| 146 | {
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| 147 | byte = digit;
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| 148 | state = 1;
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| 149 | }
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| 150 | }
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| 151 | }
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| 152 | }
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| 153 |
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| 154 | VOID GenerateRelatedMAC (MACADDR dest, const MACADDR src, const int delta)
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| 155 | {
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| 156 | COPY_MAC (dest, src);
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| 157 | dest[2] += (UCHAR) delta;
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| 158 | }
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| 159 |
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