pklaus · May 31, 2025 14:15 · Sep 4, 2019 · Mar 19, 2014 · Mar 19, 2014 · Mar 19, 2014
diff --git a/README.md b/README.md
@@ -1,15 +1,16 @@
+The mini-tool has a CLI-Interface with the following options:
+
+* Unicast or Multicast? Default: Unicast
+* Locally Administered or Globally Unique? Default: Locally Administered
+* Prescribe specific OUI (overwrites the above two)
+
 TODO
 
-* Create a CLI-Interface with the following options:
-  * Unicast or Multicast? Default: Unicast
-  * Locally Administered or Globally Unique? Default: Locally Administered
-  * Prescribe specific OUI (overwrites the above two)
-  * Number of MACs to generate (they should not collide and be piped out separated by newlines)
+* Add an option to generate a number of MACs without collisions.
 
 ### Resources
 
 * [MAC Adress](http://en.wikipedia.org/wiki/MAC_address) on Wikipedia
 * redhat's virtualization guide on [Generating a new unique MAC address](http://goo.gl/rtt5T8)
 * A Perl Script that does the same: [randmac.pl](http://www.hellion.org.uk/cgi-bin/randmac.pl?source=1)
-* The python module [`netaddr`](https://pypi.python.org/pypi/netaddr) can help you work with MAC addresses.
-
+* The python module [`netaddr`](https://pypi.python.org/pypi/netaddr) can help you work with MAC addresses.
diff --git a/randmac.py b/randmac.py
@@ -2,14 +2,36 @@
 
 import random
 
-def randomMAC():
-    return [ 0x00, 0x16, 0x3e,
-        random.randint(0x00, 0x7f),
-        random.randint(0x00, 0xff),
-        random.randint(0x00, 0xff) ]
+def random_bytes(num=6):
+    return [random.randrange(256) for _ in range(num)]
 
-def MACprettyprint(mac):
-    return ':'.join(map(lambda x: "%02x" % x, mac))
+def generate_mac(uaa=False, multicast=False, oui=None, separator=':', byte_fmt='%02x'):
+    mac = random_bytes()
+    if oui:
+        if type(oui) == str:
+            oui = [int(chunk) for chunk in oui.split(separator)]
+        mac = oui + random_bytes(num=6-len(oui))
+    else:
+        if multicast:
+            mac[0] |= 1 # set bit 0
+        else:
+            mac[0] &= ~1 # clear bit 0
+        if uaa:
+            mac[0] &= ~(1 << 1) # clear bit 1
+        else:
+            mac[0] |= 1 << 1 # set bit 1
+    return separator.join(byte_fmt % b for b in mac)
+
+def main():
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--uaa', action='store_true', help='generates a universally administered address (instead of LAA otherwise)')
+    parser.add_argument('--multicast', action='store_true', help='generates a multicast MAC (instead of unicast otherwise)')
+    parser.add_argument('--oui', help='enforces a specific organizationally unique identifier (like 00:60:2f for Cisco)')
+    parser.add_argument('--byte-fmt', default='%02x', help='The byte format. Set to %02X for uppercase hex formatting.')
+    parser.add_argument('--separator', default=':', help="The byte separator character. Defaults to ':'.")
+    args = parser.parse_args()
+    print(generate_mac(oui=args.oui, uaa=args.uaa, multicast=args.multicast, separator=args.separator, byte_fmt=args.byte_fmt))
 
 if __name__ == '__main__':
-    print(MACprettyprint(randomMAC()))
+    main()
diff --git a/randmac.py b/randmac.py
@@ -3,7 +3,7 @@
 import random
 
 def randomMAC():
-    mac = [ 0x00, 0x16, 0x3e,
+    return [ 0x00, 0x16, 0x3e,
         random.randint(0x00, 0x7f),
         random.randint(0x00, 0xff),
         random.randint(0x00, 0xff) ]

diff --git a/README.md b/README.md
@@ -10,4 +10,6 @@ TODO
 
 * [MAC Adress](http://en.wikipedia.org/wiki/MAC_address) on Wikipedia
 * redhat's virtualization guide on [Generating a new unique MAC address](http://goo.gl/rtt5T8)
-* A Perl Script that does the same: [randmac.pl](http://www.hellion.org.uk/cgi-bin/randmac.pl?source=1)
+* A Perl Script that does the same: [randmac.pl](http://www.hellion.org.uk/cgi-bin/randmac.pl?source=1)
+* The python module [`netaddr`](https://pypi.python.org/pypi/netaddr) can help you work with MAC addresses.
+
diff --git a/randmac.py b/randmac.py
diff --git a/README.md b/README.md
@@ -0,0 +1,13 @@
+TODO
+
+* Create a CLI-Interface with the following options:
+  * Unicast or Multicast? Default: Unicast
+  * Locally Administered or Globally Unique? Default: Locally Administered
+  * Prescribe specific OUI (overwrites the above two)
+  * Number of MACs to generate (they should not collide and be piped out separated by newlines)
+
+### Resources
+
+* [MAC Adress](http://en.wikipedia.org/wiki/MAC_address) on Wikipedia
+* redhat's virtualization guide on [Generating a new unique MAC address](http://goo.gl/rtt5T8)
+* A Perl Script that does the same: [randmac.pl](http://www.hellion.org.uk/cgi-bin/randmac.pl?source=1)
diff --git a/randmac.py b/randmac.py
@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+
+import random
+
+def randomMAC():
+    mac = [ 0x00, 0x16, 0x3e,
+        random.randint(0x00, 0x7f),
+        random.randint(0x00, 0xff),
+        random.randint(0x00, 0xff) ]
+
+def MACprettyprint(mac):
+    return ':'.join(map(lambda x: "%02x" % x, mac))
+
+if __name__ == '__main__':
+    print(MACprettyprint(randomMAC()))
No results found