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authorAlberto Gonzalez Iniesta <agi@inittab.org>2012-02-21 15:53:40 +0100
committerAlberto Gonzalez Iniesta <agi@inittab.org>2012-02-21 15:53:40 +0100
commit349cfa7acb95abe865209a28e417ec74b56f9bba (patch)
treead65334821b587c4ecdd461be84c94305ffdb888 /tap-win32/macinfo.c
Imported Upstream version 2.2.1upstream/2.2.1
Diffstat (limited to 'tap-win32/macinfo.c')
-rwxr-xr-xtap-win32/macinfo.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/tap-win32/macinfo.c b/tap-win32/macinfo.c
new file mode 100755
index 0000000..8d512ec
--- /dev/null
+++ b/tap-win32/macinfo.c
@@ -0,0 +1,154 @@
+/*
+ * TAP-Win32/TAP-Win64 -- A kernel driver to provide virtual tap
+ * device functionality on Windows.
+ *
+ * This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
+ *
+ * This source code is Copyright (C) 2002-2010 OpenVPN Technologies, Inc.,
+ * and is released under the GPL version 2 (see below).
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING included with this
+ * distribution); if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "macinfo.h"
+
+int
+HexStringToDecimalInt (const int p_Character)
+{
+ int l_Value = 0;
+
+ if (p_Character >= 'A' && p_Character <= 'F')
+ l_Value = (p_Character - 'A') + 10;
+ else if (p_Character >= 'a' && p_Character <= 'f')
+ l_Value = (p_Character - 'a') + 10;
+ else if (p_Character >= '0' && p_Character <= '9')
+ l_Value = p_Character - '0';
+
+ return l_Value;
+}
+
+BOOLEAN
+ParseMAC (MACADDR dest, const char *src)
+{
+ int c;
+ int mac_index = 0;
+ BOOLEAN high_digit = FALSE;
+ int delim_action = 1;
+
+ MYASSERT (src);
+ MYASSERT (dest);
+
+ CLEAR_MAC (dest);
+
+ while (c = *src++)
+ {
+ if (IsMacDelimiter (c))
+ {
+ mac_index += delim_action;
+ high_digit = FALSE;
+ delim_action = 1;
+ }
+ else if (IsHexDigit (c))
+ {
+ const int digit = HexStringToDecimalInt (c);
+ if (mac_index < sizeof (MACADDR))
+ {
+ if (!high_digit)
+ {
+ dest[mac_index] = (char)(digit);
+ high_digit = TRUE;
+ delim_action = 1;
+ }
+ else
+ {
+ dest[mac_index] = (char)(dest[mac_index] * 16 + digit);
+ ++mac_index;
+ high_digit = FALSE;
+ delim_action = 0;
+ }
+ }
+ else
+ return FALSE;
+ }
+ else
+ return FALSE;
+ }
+
+ return (mac_index + delim_action) >= sizeof (MACADDR);
+}
+
+/*
+ * Generate a MAC using the GUID in the adapter name.
+ *
+ * The mac is constructed as 00:FF:xx:xx:xx:xx where
+ * the Xs are taken from the first 32 bits of the GUID in the
+ * adapter name. This is similar to the Linux 2.4 tap MAC
+ * generator, except linux uses 32 random bits for the Xs.
+ *
+ * In general, this solution is reasonable for most
+ * applications except for very large bridged TAP networks,
+ * where the probability of address collisions becomes more
+ * than infintesimal.
+ *
+ * Using the well-known "birthday paradox", on a 1000 node
+ * network the probability of collision would be
+ * 0.000116292153. On a 10,000 node network, the probability
+ * of collision would be 0.01157288998621678766.
+ */
+
+VOID GenerateRandomMac (MACADDR mac, const unsigned char *adapter_name)
+{
+ unsigned const char *cp = adapter_name;
+ unsigned char c;
+ unsigned int i = 2;
+ unsigned int byte = 0;
+ int brace = 0;
+ int state = 0;
+
+ CLEAR_MAC (mac);
+
+ mac[0] = 0x00;
+ mac[1] = 0xFF;
+
+ while (c = *cp++)
+ {
+ if (i >= sizeof (MACADDR))
+ break;
+ if (c == '{')
+ brace = 1;
+ if (IsHexDigit (c) && brace)
+ {
+ const unsigned int digit = HexStringToDecimalInt (c);
+ if (state)
+ {
+ byte <<= 4;
+ byte |= digit;
+ mac[i++] = (unsigned char) byte;
+ state = 0;
+ }
+ else
+ {
+ byte = digit;
+ state = 1;
+ }
+ }
+ }
+}
+
+VOID GenerateRelatedMAC (MACADDR dest, const MACADDR src, const int delta)
+{
+ COPY_MAC (dest, src);
+ dest[2] += (UCHAR) delta;
+}