From 349cfa7acb95abe865209a28e417ec74b56f9bba Mon Sep 17 00:00:00 2001
From: Alberto Gonzalez Iniesta <agi@inittab.org>
Date: Tue, 21 Feb 2012 15:53:40 +0100
Subject: Imported Upstream version 2.2.1

---
 tap-win32/macinfo.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100755 tap-win32/macinfo.c

(limited to 'tap-win32/macinfo.c')

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;
+}
-- 
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