Linux interface bonding: Fix gateway routes (#1774)

netsim/extra/bonding/linux-clab.j2

@@ -4,11 +4,10 @@ set -e
 
 {# Bonding device is created by 'initial' module - add members #}
 {% for intf in interfaces|default([]) if intf.bonding.members is defined %}
-ip link set dev {{ intf.ifname }} down
+{# Don't bring the bond interface down, it will loose any routes #}
 {%   for member in intf.bonding.members %}
 ip link set dev {{ member }} down
 ip link set dev {{ member }} master {{ intf.ifname }}
 ip link set dev {{ member }} up
 {%   endfor %}
-ip link set dev {{ intf.ifname }} up
 {% endfor %}

netsim/extra/bonding/plugin.py

@@ -6,6 +6,8 @@
 
 _config_name = 'bonding'
 
+ATTS_TO_MOVE = ['ipv4','ipv6','vlan','_vlan_mode','vlan_name','gateway']
+
 '''
 add_bond_interfaces - append interface data to node.interfaces for bonding template to read and implement
 '''
@@ -29,17 +31,42 @@ def add_bond_interfaces(node: Box, bonds: typing.Dict[int,Box], topology: Box) -
     }
     if 'primary' in bond:
       bond_if['bonding']['primary'] = bond['primary']
-    for af in ['ipv4','ipv6']:
+    for af in ATTS_TO_MOVE:
       if af in bond:
         bond_if[af] = bond[af]     # Take the first one, if any
     node.interfaces.append(bond_if)
 
+"""
+Update the link and all neighbors with the new interface name
+"""
+def update_neighbors( node: Box, intf: Box, topology: Box ) -> bool:
+  link = topology.links[ intf.linkindex-1 ]
+  if 'virtual_interface' in intf or link.node_count!=2:
+    log.error( f"{intf.name}: 'bonding.ifindex' can only be applied to interfaces on direct p2p links",
+               category=log.IncorrectAttr,module=_config_name)
+    return False
+
+  intf.neighbors = [ { 'node': n.node, 'ifname': n.ifname } for n in intf.neighbors ]  # Clear any IP addresses from neighbors
+  bond_interface_name = topology.defaults.bonding.bond_interface_name
+  ifname = strings.eval_format(bond_interface_name, intf)
+  for if2 in link.interfaces:
+    if if2.node==node.name:
+      if2.ifname = ifname
+    else:
+      nb = topology.nodes[if2.node]
+      for if3 in nb.interfaces:
+        for n2 in if3.neighbors:
+          if n2.node==node.name:
+            n2.ifname = ifname
+  return True
+
 '''
-post_transform hook
+post_link_transform hook
 
-Apply plugin config to nodes with interfaces marked with 'bonding.ifindex', for devices that support this plugin
+Apply plugin config to nodes with interfaces marked with 'bonding.ifindex', for devices that support this plugin.
+Executes after IP addresses are assigned, but before vlan gateways are fixed
 '''
-def post_transform(topology: Box) -> None:
+def post_link_transform(topology: Box) -> None:
   global _config_name
   bond_mode = topology.get('bonding.mode','active-backup')
   bonds : Box = data.get_empty_box()                   # Map of bonds per node, indexed by bonding.ifindex
@@ -54,43 +81,26 @@ def post_transform(topology: Box) -> None:
                    category=log.IncorrectAttr,module=_config_name)
         continue
 
-      link = topology.links[ intf.linkindex-1 ]
-      if 'virtual_interface' in intf or link.node_count!=2:
-        log.error( f"{intf.name}: 'bonding.ifindex' can only be applied to interfaces on direct p2p links",
-                   category=log.IncorrectAttr,module=_config_name)
+      if not update_neighbors(node,intf,topology):
         continue
+
       clone = data.get_box(intf)
       if node.name in bonds and bond_ifindex in bonds[node.name]:
         bonds[node.name][bond_ifindex]['members'].append( clone.ifname )
-        for att in ['ipv4','ipv6']:
+        for att in ATTS_TO_MOVE:
           intf.pop(att,None)
       else:
         mode = intf.get('bonding.mode',bond_mode)
         bonds[node.name][bond_ifindex] = { 'neighbors': intf.neighbors, 'members': [ clone.ifname ], 'mode': mode }
-        for att in ['ipv4','ipv6']:                    # Move any ips (from first member link)
+        for att in ATTS_TO_MOVE:                       # Move any ips (from first member link)
           if att in intf:
             bonds[node.name][bond_ifindex][att] = intf.pop(att,None)
       if intf.get('bonding.primary',False):
         bonds[node.name][bond_ifindex]['primary'] = intf.ifname
-
-      #
-      # Clean up interface neighbors leaving only directly reachable peers (as opposed to - say - 
-      # VLAN neighbors in the form of other hosts), moving the rest to bond[x].neighbors
-      #
-      intf.neighbors = [ { 'ifname': i.ifname, 'node': i.node } for i in link.interfaces if i.node!=node.name ]
       intf.prefix = False                              # L2 interface
-      intf.pop('name',None)
 
-  # Interface neighbors may need to be updated to reflect the new bonded interface
-  bond_interface_name = topology.defaults.bonding.bond_interface_name
   for node in topology.nodes.values():                 # For each node
     if node.name in bonds:                             # ...that has 1 or more bonds
-      for bond in bonds[node.name].values():           # ...for each bond
-        for i in bond.neighbors:                       # ...for each neighbor of that bond
-          if i.node in bonds:                          # ...check if the node also has bonds
-            for i2,b2 in bonds[i.node].items():        # If so, for each such bond
-              if i.ifname in b2['members']:            # if the interface connecting to <node> is a member
-                i.ifname = strings.eval_format(bond_interface_name, { 'ifindex': i2 })
-                continue
       add_bond_interfaces(node,bonds[node.name],topology)
       api.node_config(node,_config_name)               # Remember that we have to do extra configuration
+

netsim/modules/vlan.py

@@ -1149,7 +1149,9 @@ def fix_vlan_gateways(topology: Box) -> None:
     if node.get('role') != 'host':                                    # Fix first-hop gateways only for hosts
       continue
     for intf in node.get('interfaces',[]):                            # Iterate over all interfaces
-      if intf.get('gateway.ipv4',None):                               # ... that don't have an IPv4 gateway
+      if not intf.get('ipv4',None):                                   # ... that are IP interfaces
+        continue
+      if intf.get('gateway.ipv4',None):                               # ... that don't already have an IPv4 gateway
         continue
 
       gw_found = False