Add python script to doc/protocol.txt

doc/protocol.txt

@@ -70,3 +70,39 @@ function check_if_minetestserver_up($host, $port)
 	return false;
 }
 
+- Here's a Python script for checking if a minetest server is up, confirmed working
+#!/usr/bin/env python
+import sys, time, socket
+address = ""
+port = 30000
+if len(sys.argv) <= 1:
+    print("Usage: %s <address>" % sys.argv[0])
+    exit()
+if ':' in sys.argv[1]:
+    address = sys.argv[1].split(':')[0]
+    try:
+        port = int(sys.argv[1].split(':')[1])
+    except ValueError:
+        print("Please specify a valid port")
+        exit()
+else:
+    address = sys.argv[1]
+
+try:
+    start = time.time()
+    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    sock.settimeout(2.0)
+    buf = "\x4f\x45\x74\x03\x00\x00\x00\x01"
+    sock.sendto(buf, (address, port))
+    data, addr = sock.recvfrom(1000)
+    if data:
+        peer_id = data[12:14]
+        buf = "\x4f\x45\x74\x03" + peer_id + "\x00\x00\x03"
+        sock.sendto(buf, (address, port))
+        sock.close()
+        end = time.time()
+        print("%s is up (%0.5fms)" % (sys.argv[1],end-start))
+    else:
+        print("%s seems to be down " % sys.argv[1])
+except:
+    print("%s seems to be down " % sys.argv[1])