allow custom paths for chaining

by moving from current_hop to pathindex we can allow loops in the path.

One problem still remains: paths containing a loop with a single hop will not be set up correctly.
say: s1 -> s2 -> s1
as the 'IN_PORT' command is needed, that ryu does not support.

diff --git a/src/emuvim/dcemulator/net.py b/src/emuvim/dcemulator/net.py
index 531e5f1..faf758c 100755 (executable)
--- a/src/emuvim/dcemulator/net.py
+++ b/src/emuvim/dcemulator/net.py
@@ -274,17 +274,22 @@ class DCNetwork(Containernet):
         :param cookie: cookie for the installed flowrules (can be used later as identifier for a set of installed chains)
         :param match: custom match entry to be added to the flowrules (default: only in_port and vlan tag)
         :param priority: custom flowrule priority
         :param cookie: cookie for the installed flowrules (can be used later as identifier for a set of installed chains)
         :param match: custom match entry to be added to the flowrules (default: only in_port and vlan tag)
         :param priority: custom flowrule priority

+        :param path: custom path between the two VNFs (list of switches)

         :return: output log string
         """
         cmd = kwargs.get('cmd')
         if cmd == 'add-flow':
             ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
             if kwargs.get('bidirectional'):
         :return: output log string
         """
         cmd = kwargs.get('cmd')
         if cmd == 'add-flow':
             ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
             if kwargs.get('bidirectional'):

+                if kwargs.get('path') is not None:
+                    kwargs['path'] = list(reversed(kwargs.get('path')))

                 ret = ret +'\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)
 
         elif cmd == 'del-flows':
             ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
             if kwargs.get('bidirectional'):
                 ret = ret +'\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)
 
         elif cmd == 'del-flows':
             ret = self._chainAddFlow(vnf_src_name, vnf_dst_name, vnf_src_interface, vnf_dst_interface, **kwargs)
             if kwargs.get('bidirectional'):

+                if kwargs.get('path') is not None:
+                    kwargs['path'] = list(reversed(kwargs.get('path')))

                 ret = ret + '\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)
 
         else:
                 ret = ret + '\n' + self._chainAddFlow(vnf_dst_name, vnf_src_name, vnf_dst_interface, vnf_src_interface, **kwargs)
 
         else:


@@ -337,20 +342,21 @@ class DCNetwork(Containernet):
                     dst_sw_outport_nr = link_dict[link]['src_port_nr']
                     break
 
                     dst_sw_outport_nr = link_dict[link]['src_port_nr']
                     break
 

-
-        # get shortest path
-        try:
-            # returns the first found shortest path
-            # if all shortest paths are wanted, use: all_shortest_paths
-            path = nx.shortest_path(self.DCNetwork_graph, src_sw, dst_sw, weight=kwargs.get('weight'))
-        except:
-            LOG.exception("No path could be found between {0} and {1} using src_sw={2} and dst_sw={3}".format(
-                vnf_src_name, vnf_dst_name, src_sw, dst_sw))
-            LOG.debug("Graph nodes: %r" % self.DCNetwork_graph.nodes())
-            LOG.debug("Graph edges: %r" % self.DCNetwork_graph.edges())
-            for e, v in self.DCNetwork_graph.edges():
-                LOG.debug("%r" % self.DCNetwork_graph[e][v])
-            return "No path could be found between {0} and {1}".format(vnf_src_name, vnf_dst_name)
+        path = kwargs.get('path')
+        if path is None:
+            # get shortest path
+            try:
+                # returns the first found shortest path
+                # if all shortest paths are wanted, use: all_shortest_paths
+                path = nx.shortest_path(self.DCNetwork_graph, src_sw, dst_sw, weight=kwargs.get('weight'))
+            except:
+                LOG.exception("No path could be found between {0} and {1} using src_sw={2} and dst_sw={3}".format(
+                    vnf_src_name, vnf_dst_name, src_sw, dst_sw))
+                LOG.debug("Graph nodes: %r" % self.DCNetwork_graph.nodes())
+                LOG.debug("Graph edges: %r" % self.DCNetwork_graph.edges())
+                for e, v in self.DCNetwork_graph.edges():
+                    LOG.debug("%r" % self.DCNetwork_graph[e][v])
+                return "No path could be found between {0} and {1}".format(vnf_src_name, vnf_dst_name)

 
         LOG.info("Path between {0} and {1}: {2}".format(vnf_src_name, vnf_dst_name, path))
 
 
         LOG.info("Path between {0} and {1}: {2}".format(vnf_src_name, vnf_dst_name, path))
 


@@ -367,10 +373,10 @@ class DCNetwork(Containernet):
         for i in range(0,len(path)):
             current_node = self.getNodeByName(current_hop)
 
         for i in range(0,len(path)):
             current_node = self.getNodeByName(current_hop)
 

-            if path.index(current_hop) < len(path)-1:
-                next_hop = path[path.index(current_hop)+1]
+            if i < len(path) - 1:
+                next_hop = path[i + 1]

             else:
             else:

-                #last switch reached
+                # last switch reached

                 next_hop = vnf_dst_name
 
             next_node = self.getNodeByName(next_hop)
                 next_hop = vnf_dst_name
 
             next_node = self.getNodeByName(next_hop)


@@ -391,7 +397,7 @@ class DCNetwork(Containernet):
             if isinstance( current_node, OVSSwitch ):
                 kwargs['vlan'] = vlan
                 kwargs['path'] = path
             if isinstance( current_node, OVSSwitch ):
                 kwargs['vlan'] = vlan
                 kwargs['path'] = path

-                kwargs['current_hop'] = current_hop
+                kwargs['pathindex'] = i

 
                 if self.controller == RemoteController:
                     ## set flow entry via ryu rest api
 
                 if self.controller == RemoteController:
                     ## set flow entry via ryu rest api


@@ -416,7 +422,8 @@ class DCNetwork(Containernet):
         match_input = kwargs.get('match')
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')
         match_input = kwargs.get('match')
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')

-        current_hop = kwargs.get('current_hop')
+        index = kwargs.get('pathindex')
+

         vlan = kwargs.get('vlan')
         priority = kwargs.get('priority')
 
         vlan = kwargs.get('vlan')
         priority = kwargs.get('priority')
 


@@ -439,7 +446,7 @@ class DCNetwork(Containernet):
         if cmd == 'add-flow':
             prefix = 'stats/flowentry/add'
             if vlan != None:
         if cmd == 'add-flow':
             prefix = 'stats/flowentry/add'
             if vlan != None:

-                if path.index(current_hop) == 0:  # first node
+                if index == 0:  # first node

                     action = {}
                     action['type'] = 'PUSH_VLAN'  # Push a new VLAN tag if a input frame is non-VLAN-tagged
                     action['ethertype'] = 33024   # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
                     action = {}
                     action['type'] = 'PUSH_VLAN'  # Push a new VLAN tag if a input frame is non-VLAN-tagged
                     action['ethertype'] = 33024   # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame


@@ -450,7 +457,7 @@ class DCNetwork(Containernet):
                     # ryu expects the field to be masked
                     action['value'] = vlan | 0x1000
                     flow['actions'].append(action)
                     # ryu expects the field to be masked
                     action['value'] = vlan | 0x1000
                     flow['actions'].append(action)

-                elif path.index(current_hop) == len(path) - 1:  # last node
+                elif index == len(path) -1:  # last node

                     match += ',dl_vlan=%s' % vlan
                     action = {}
                     action['type'] = 'POP_VLAN'
                     match += ',dl_vlan=%s' % vlan
                     action = {}
                     action['type'] = 'POP_VLAN'


@@ -485,7 +492,7 @@ class DCNetwork(Containernet):
         match_input = kwargs.get('match')
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')
         match_input = kwargs.get('match')
         cmd = kwargs.get('cmd')
         path = kwargs.get('path')

-        current_hop = kwargs.get('current_hop')
+        index = kwargs.get('pathindex')

         vlan = kwargs.get('vlan')
 
         s = ','
         vlan = kwargs.get('vlan')
 
         s = ','


@@ -497,10 +504,10 @@ class DCNetwork(Containernet):
         if cmd == 'add-flow':
             action = 'action=%s' % switch_outport_nr
             if vlan != None:
         if cmd == 'add-flow':
             action = 'action=%s' % switch_outport_nr
             if vlan != None:

-                if path.index(current_hop) == 0:  # first node
+                if index == 0: # first node

                     action = ('action=mod_vlan_vid:%s' % vlan) + (',output=%s' % switch_outport_nr)
                     match = '-O OpenFlow13 ' + match
                     action = ('action=mod_vlan_vid:%s' % vlan) + (',output=%s' % switch_outport_nr)
                     match = '-O OpenFlow13 ' + match

-                elif path.index(current_hop) == len(path) - 1:  # last node
+                elif index == len(path) - 1:  # last node

                     match += ',dl_vlan=%s' % vlan
                     action = 'action=strip_vlan,output=%s' % switch_outport_nr
                 else:  # middle nodes
                     match += ',dl_vlan=%s' % vlan
                     action = 'action=strip_vlan,output=%s' % switch_outport_nr
                 else:  # middle nodes