Add Scenario classes

route-0.py

@@ -7,9 +7,10 @@ from mininet.cli import CLI
 
 from router import Router
 from topology.two_nodes.topo import NetTopo as TwoNodes
+from scenario import Basic
 
 
-def run(topo):
+def run(topo, scenario):
     """Start a network scenario.
     """
 
@@ -18,20 +19,33 @@ def run(topo):
     os.system("mn -c >/dev/null 2>&1")
     os.system("killall -9 zebra staticd > /dev/null 2>&1")
 
-    net = Mininet(topo=topo(), switch=Router)
+    net = Mininet(topo=topo, switch=Router)
     net.start()
+    scenario.setup(net)
 
+    # WARNING: FRR can get confused unless all daemons on each node are started
+    #          together.
     for node in net.switches:
-        # Start Zebra (routing table daemon)
+        if node in scenario.routers:
-        node.cmd("/usr/lib/frr/zebra"
+            # Enable IP forwarding
-                 " -f %s/zebra/%s.conf"
+            node.cmd("sysctl -w net.ipv4.ip_forward=1")
-                 " -d"
+            node.waitOutput()
-                 " -i /tmp/%s-zebra.pid"
-                 " > /tmp/%s-zebra.out 2>&1"
-                 % (topo.topo_dir, node.name, node.name, node.name))
-        node.waitOutput()
 
-        if node.name.startswith('h'):
+        if node in scenario.zebra:
+            # Start Zebra (routing table daemon)
+            node.cmd("/usr/lib/frr/zebra"
+                     " -f %s/zebra/%s.conf"
+                     " -d"
+                     " -i /tmp/%s-zebra.pid"
+                     " > /tmp/%s-zebra.out 2>&1"
+                     % (topo.topo_dir, node.name, node.name, node.name))
+            node.waitOutput()
+
+            # Delete spare loopback address for convenience
+            node.cmd("ip addr del 127.0.0.1/8 dev lo")
+            node.waitOutput()
+
+        if node in scenario.staticd:
             # Start static route daemon
             node.cmd("/usr/lib/frr/staticd"
                      " -f %s/staticd/%s.conf"
@@ -41,19 +55,10 @@ def run(topo):
                      % (topo.topo_dir, node.name, node.name, node.name))
             node.waitOutput()
 
-        if node.name.startswith('R'):
-            # Enable IP forwarding
-            node.cmd("sysctl -w net.ipv4.ip_forward=1")
-            node.waitOutput()
-
-            # Delete spare loopback address for convenience
-            node.cmd("ip addr del 127.0.0.1/8 dev lo")
-            node.waitOutput()
-
     CLI(net)
     net.stop()
     os.system("killall -9 zebra staticd")
 
 
 if __name__ == "__main__":
-    run(TwoNodes)
+    run(TwoNodes(), Basic())

scenario.py

@@ -0,0 +1,82 @@
+class Scenario(object):
+    """Class that describes a network scenario.  A scenario defines which nodes
+    are routers and which are hosts as well as which nodes need to start which
+    daemons.
+
+    """
+
+    def __init__(self):
+        self._routers = None
+        self._hosts = None
+        self._zebra = None
+        self._staticd = None
+
+    @property
+    def routers(self):
+        """Set of nodes that are routers.
+
+        """
+        return self._routers
+
+    @property
+    def hosts(self):
+        """Set of nodes that are hosts.
+
+        """
+        return self._hosts
+
+    @property
+    def zebra(self):
+        """Set of nodes that should run zebra.
+
+        """
+        return self._zebra
+
+    @property
+    def staticd(self):
+        """Set of nodes that should run staticd.
+
+        """
+        return self._staticd
+
+    def _routers_and_hosts(self, net):
+        """Separate nodes into routers and hosts based on their names.
+
+        """
+        self._routers = set()
+        self._hosts = set()
+
+        for node in net.switches:
+            if node.name.startswith('R'):
+                self._routers.add(node)
+            else:
+                self._hosts.add(node)
+
+    def setup(self, net):
+        """Setup the scenario.
+
+        """
+        self._routers_and_hosts(net)
+        self._zebra = set()
+        self._staticd = set()
+
+
+class Plain(Scenario):
+    """In a Plain scenario no daemons are run.
+
+    """
+
+
+class Basic(Scenario):
+    """In a Basic scenario, all nodes run zebra, and all hosts run staticd to
+    setup a default route.
+
+    """
+
+    def __init__(self):
+        Scenario.__init__(self)
+
+    def setup(self, net):
+        self._routers_and_hosts(net)
+        self._zebra = self._routers.union(self._hosts)
+        self._staticd = self._hosts

topology/two_nodes/staticd/h1_1.conf

@@ -1,7 +1,7 @@
-! -*- zebra -*-
+! -*- staticd -*-
 
 hostname h1_1
 
 ip route 0.0.0.0/0 10.1.0.254
 
-log file /tmp/h1_1-staticd.log
+log file /tmp/h1_1-staticd.log debugging

topology/two_nodes/staticd/h2_1.conf

@@ -1,7 +1,7 @@
-! -*- zebra -*-
+! -*- staticd -*-
 
 hostname h2_1
 
 ip route 0.0.0.0/0 10.2.0.254
 
-log file /tmp/h2_1-staticd.log
+log file /tmp/h2_1-staticd.log debugging

topology/two_nodes/zebra/R1.conf

@@ -11,4 +11,4 @@ interface R1-eth1
 interface R1-eth2
   ip address 10.1.0.254/24
 
-log file /tmp/R1-zebra.log
+log file /tmp/R1-zebra.log debugging

topology/two_nodes/zebra/R2.conf

@@ -11,4 +11,4 @@ interface R2-eth1
 interface R2-eth2
   ip address 10.2.0.254/24
 
-log file /tmp/R2-zebra.log
+log file /tmp/R2-zebra.log debugging

topology/two_nodes/zebra/h1_1.conf

@@ -5,4 +5,4 @@ hostname h1_1
 interface h1_1-eth1
   ip address 10.1.0.1/24
 
-log file /tmp/h1_1-zebra.log
+log file /tmp/h1_1-zebra.log debugging

topology/two_nodes/zebra/h2_1.conf

@@ -5,4 +5,4 @@ hostname h2_1
 interface h2_1-eth1
   ip address 10.2.0.1/24
 
-log file /tmp/h2_1-zebra.log
+log file /tmp/h2_1-zebra.log debugging