Added quality of service(QOS) via Differentiated services (#330)

* Added quality of service(QOS) via Differentiated services

* Altered to classify network traffic in Ingress

* Updated readme for QoS

exercises/qos/send.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+import argparse
+import socket
+
+from scapy.all import sendp, send, hexdump, get_if_list, get_if_hwaddr
+from scapy.all import Ether, IP, UDP, TCP
+
+from time import sleep
+
+
+def get_if():
+    iface = None
+    for i in get_if_list():
+        if "eth0" in i:
+            iface = i
+            break
+    if not iface:
+        print "Cannot find eth0 interface"
+        exit(1)
+    return iface
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--p", help="Protocol name To send TCP/UDP etc packets", type=str)
+    parser.add_argument("--des", help="IP address of the destination", type=str)
+    parser.add_argument("--m", help="Raw Message", type=str)
+    parser.add_argument("--dur", help="in seconds", type=str)
+    args = parser.parse_args()
+
+    if args.p and args.des and args.m and args.dur:
+        addr = socket.gethostbyname(args.des)
+        iface = get_if()
+        if args.p == 'UDP':
+            pkt = Ether(src=get_if_hwaddr(iface), dst="ff:ff:ff:ff:ff:ff") / IP(dst=addr, tos=1) / UDP(dport=4321, sport=1234) / args.m
+            pkt.show2()
+            try:
+                for i in range(int(args.dur)):
+                    sendp(pkt, iface=iface)
+                    sleep(1)
+            except KeyboardInterrupt:
+                raise
+        elif args.p == 'TCP':
+            pkt = Ether(src=get_if_hwaddr(iface), dst="ff:ff:ff:ff:ff:ff") / IP(dst=addr, tos=1) / TCP() / args.m
+            pkt.show2()
+            try:
+                for i in range(int(args.dur)):
+                    sendp(pkt, iface=iface)
+                    sleep(1)
+            except KeyboardInterrupt:
+                raise
+
+
+if __name__ == '__main__':
+    main()