xt_pknock: import digest generation utility

extensions/pknock/gen_hmac.py

@@ -0,0 +1,17 @@
+from Crypto.Hash import SHA256
+from Crypto.Hash import MD5
+import sys
+import hmac
+import struct
+import socket
+from time import time
+
+def gen_hmac(secret, ip):
+    epoch_mins = (long)(time()/60)
+    s = hmac.HMAC(secret, digestmod = SHA256)
+    s.update(socket.inet_aton(socket.gethostbyname(ip)))
+    s.update(struct.pack("i", epoch_mins)) # "i" is for integer
+    print s.hexdigest()
+
+if __name__ == '__main__':
+	gen_hmac(sys.argv[1], sys.argv[2])