topogen: add support for setting link state

This commit changes how topology links are made in order to support
discovering who and what link is the node interface connected to. After
that, the implementation of the link state change functions were trivial
as calling a command in the node shell.

The method run() was moved from TopoRouter to TopoGear so all equipment
types can benefit from this code.

diff --git a/tests/topotests/lib/topogen.py b/tests/topotests/lib/topogen.py
index 250d4ba216d5c0c73e4f75672ee4812935ff9e27..08bff0fa167ee718d9e3a1598597a95da3d289d5 100644 (file)
--- a/tests/topotests/lib/topogen.py
+++ b/tests/topotests/lib/topogen.py
@@ -149,9 +149,12 @@ class Topogen(object):
             raise ValueError('invalid node2 type')
 
         if ifname1 is None:
-            ifname1 = node1.register_link(ifname1)
+            ifname1 = node1.new_link()
         if ifname2 is None:
-            ifname1 = node2.register_link(ifname1)
+            ifname2 = node2.new_link()
+
+        node1.register_link(ifname1, node2, ifname2)
+        node2.register_link(ifname2, node1, ifname1)
         self.topo.addLink(node1.name, node2.name,
                           intfName1=ifname1, intfName2=ifname2)
 
@@ -218,9 +221,16 @@ class TopoGear(object):
         self.tgen = None
         self.name = None
         self.cls = None
-        self.links = []
+        self.links = {}
         self.linkn = 0
 
+    def run(self, command):
+        """
+        Runs the provided command string in the router and returns a string
+        with the response.
+        """
+        return self.tgen.net[self.name].cmd(command)
+
     def add_link(self, node, myif=None, nodeif=None):
         """
         Creates a link (connection) between myself and the specified node.
@@ -230,20 +240,58 @@ class TopoGear(object):
         """
         self.tgen.add_link(self, node, myif, nodeif)
 
-    def register_link(self, ifname=None):
+    def link_enable(self, myif, enabled=True):
         """
-        Register and returns an interface. If no interface name is specified,
-        then an standard interface name is used.
+        Set this node interface administrative state.
+        myif: this node interface name
+        enabled: whether we should enable or disable the interface
         """
-        if ifname is None:
-            ifname = '{}-eth{}'.format(self.name, self.linkn)
-        if ifname in self.links:
-            raise KeyError('interface already exists')
+        if myif not in self.links.keys():
+            raise KeyError('interface doesn\'t exists')
+
+        if enabled is True:
+            operation = 'up'
+        else:
+            operation = 'down'
+
+        return self.run('ip link set dev {} {}'.format(myif, operation))
+
+    def peer_link_enable(self, myif, enabled=True):
+        """
+        Set the peer interface administrative state.
+        myif: this node interface name
+        enabled: whether we should enable or disable the interface
+
+        NOTE: this is used to simulate a link down on this node, since when the
+        peer disables their interface our interface status changes to no link.
+        """
+        if myif not in self.links.keys():
+            raise KeyError('interface doesn\'t exists')
+
+        node, nodeif = self.links[myif]
+        node.link_enable(nodeif, enabled)
 
+    def new_link(self):
+        """
+        Generates a new unique link name.
+
+        NOTE: This function should only be called by Topogen.
+        """
+        ifname = '{}-eth{}'.format(self.name, self.linkn)
         self.linkn += 1
-        self.links.append(ifname)
         return ifname
 
+    def register_link(self, myif, node, nodeif):
+        """
+        Register link between this node interface and outside node.
+
+        NOTE: This function should only be called by Topogen.
+        """
+        if myif in self.links.keys():
+            raise KeyError('interface already exists')
+
+        self.links[myif] = (node, nodeif)
+
 class TopoRouter(TopoGear):
     """
     Router abstraction.
@@ -325,13 +373,6 @@ class TopoRouter(TopoGear):
         """
         return self.tgen.net[self.name].startRouter()
 
-    def run(self, command):
-        """
-        Runs the provided command string in the router and returns a string
-        with the response.
-        """
-        return self.tgen.net[self.name].cmd(command)
-
     def vtysh_cmd(self, command):
         """
         Runs the provided command string in the vty shell and returns a string