bpo-9678: Fix determining the MAC address in the uuid module. (#4264)

* Using ifconfig on NetBSD and OpenBSD.
* Using arp on Linux, FreeBSD, NetBSD and OpenBSD.

Based on patch by Takayuki Shimizukawa.

Lib/uuid.py

@@ -370,8 +370,9 @@ def _find_mac(command, args, hw_identifiers, get_index):
 def _ifconfig_getnode():
     """Get the hardware address on Unix by running ifconfig."""
     # This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes.
+    keywords = (b'hwaddr', b'ether', b'address:', b'lladdr')
     for args in ('', '-a', '-av'):
-        mac = _find_mac('ifconfig', args, [b'hwaddr', b'ether'], lambda i: i+1)
+        mac = _find_mac('ifconfig', args, keywords, lambda i: i+1)
         if mac:
             return mac
 
@@ -391,7 +392,20 @@ def _arp_getnode():
         return None
 
     # Try getting the MAC addr from arp based on our IP address (Solaris).
-    return _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1)
+    mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1)
+    if mac:
+        return mac
+
+    # This works on OpenBSD
+    mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1)
+    if mac:
+        return mac
+
+    # This works on Linux, FreeBSD and NetBSD
+    mac = _find_mac('arp', '-an', [os.fsencode('(%s)' % ip_addr)],
+                    lambda i: i+2)
+    if mac:
+        return mac
 
 def _lanscan_getnode():
     """Get the hardware address on Unix by running lanscan."""

Misc/NEWS.d/next/Library/2017-11-03-22-05-47.bpo-9678.oD51q6.rst

@@ -0,0 +1,6 @@
+Fixed determining the MAC address in the uuid module:
+
+* Using ifconfig on NetBSD and OpenBSD.
+* Using arp on Linux, FreeBSD, NetBSD and OpenBSD.
+
+Based on patch by Takayuki Shimizukawa.