Added WackySender

Sometimes is fudges the seqno to simulate loss. This is for testing the
receiver's ability to ack the right number.

WackySender.py

@@ -0,0 +1,40 @@
+import socket
+import sys
+import random
+
+import Checksum
+
+DEST="rutherford.cs.berkeley.edu"
+DPORT=33122
+SPORT=random.randint(10000,40000)
+
+socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+socket.bind(('',SPORT))
+
+seqno = 0
+while True:
+    msg = raw_input("Message:")
+    rand_added = 0
+    msg_type = 'data'
+    if seqno == 0:
+        msg_type = 'syn'
+    elif msg == "done":
+        msg_type = 'end'
+    else:
+        rand_added = random.randint(0,1)
+    message = "%s|%d|%s|" % (msg_type,seqno+rand_added,msg)
+    checksum = Checksum.generate_checksum(message)
+    packet = "%s%s" % (message,checksum)
+    print "sent: %s" % packet
+    socket.sendto(packet,(DEST,DPORT))
+    response,address = socket.recvfrom(8192)
+    if Checksum.validate_checksum(response):
+        print "recv: %s" % response
+    else:
+        print "recv: %s <--- CHECKSUM FAILED" % response
+
+    if msg_type == 'end':
+        break
+    else:
+        if rand_added == 0:
+            seqno += 1