Add comments and cleanup

Uebung1/controller_1_4_2.py

@@ -1,3 +1,6 @@
+# Abgabe von:
+# Jutta Seth, Janek Schoffit, Eva Högner
+# Problem 1.4 (Flow-based IP Anycast)
 from ryu.base import app_manager
 from ryu.controller import ofp_event
 from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
@@ -210,6 +213,7 @@ class L3Switch(app_manager.RyuApp):
                                   in_port=in_port, actions=actions, data=data)
         datapath.send_msg(out)
 
+    # Get the next port where a package should be forwarded
     def anycast_next(self):
         if self.anycastIndex >= 2:
             self.anycastIndex = 0
@@ -222,18 +226,18 @@ class L3Switch(app_manager.RyuApp):
         ofproto = datapath.ofproto
         parser = datapath.ofproto_parser
 
+        # Retrieve tcp tuple
         tcp_pkt = packet.get_protocol(tcp.tcp)
         tcp_src = tcp_pkt.src_port
         tcp_dst = tcp_pkt.dst_port
 
-        self.logger.info("src: %s, dst: %s", tcp_src, tcp_dst)
+        # Get the anycast port
         port = self.anycast_next()
 
         actions = [parser.OFPActionSetField(eth_dst = self.port_to_mac[dpid][str(port)]),
                     parser.OFPActionOutput(port)]
 
         match = parser.OFPMatch(eth_type=0x0800, ipv4_src=ipv4_pkt.src, ip_proto=6, tcp_src=tcp_src, ipv4_dst=ipv4_pkt.dst, tcp_dst=tcp_dst)
-        #match = parser.OFPMatch(in_port=in_port, eth_dst=frame.dst, tcp_src=tcp_src)
 
         if buffer_id != ofproto.OFP_NO_BUFFER:
             self.add_flow(datapath, 1, match, actions, buffer_id)
@@ -280,7 +284,6 @@ class L3Switch(app_manager.RyuApp):
         self.ip_to_mac.setdefault(dpid, {})
 
         self.logger.info("packet in dpid: %s, src: %s, dest: %s, in_port: %s", dpid, src, dst, in_port)
-        #self.logger.info(pkt)
 
         #learn mac to port mapping
         if src not in self.mac_to_port[dpid]:
@@ -291,13 +294,13 @@ class L3Switch(app_manager.RyuApp):
             return
 
         if eth.ethertype == ether_types.ETH_TYPE_IP:
-
             ipv4_pkt = pkt.get_protocol(ipv4.ipv4)
             #check if packet is for this switch
             if ipv4_pkt.dst == self.IP_ADDR:
                 icmp_pkt = pkt.get_protocol(icmp.icmp)
                 if icmp_pkt:
                     self.do_icmp(datapath, in_port, eth, ipv4_pkt, icmp_pkt)
+            # Do anycast if the package contains the anycast dst-IP
             if ipv4_pkt.dst == "10.0.0.100":
                 self.do_anycast(datapath, dpid, pkt, eth, in_port, ipv4_pkt, msg.buffer_id)
                 return