Rewrite 'ebgp.utils' plugin to use the plugin defaults functionality

netsim/extra/ebgp.utils/defaults.yml

@@ -0,0 +1,28 @@
+# ebgp.utils default settings -- mostly attributes
+#
+---
+bgp:
+  attributes:
+    global:
+      tcp_ao:
+        type: str
+        valid_values: ['aes-128-cmac','hmac-sha-1','']
+        true_value: hmac-sha-1
+    node:
+      tcp_ao:
+        copy: global
+    interface:
+      allowas_in: 
+        type: int
+        true_value: 1
+        min_value: 1
+        max_value: 10
+      as_override: bool
+      default_originate: bool
+      password: str
+      tcp_ao:
+        copy: global
+    link:
+      password: str
+      tcp_ao:
+        copy: global

netsim/extra/ebgp.utils/plugin.py

@@ -2,92 +2,46 @@
 from netsim.utils import log
 from netsim import api
 
-"""
-Adds a custom bgp.{allowas_in,as_override,default_originate} as link->node (interface) attribute
-Also adds tcp_ao attribute as global and per-link option
-"""
-def init(topology: Box) -> None:
-    attr = topology.defaults.bgp.attributes
-    attr.interface.allowas_in = { 'type': 'int', 'true_value': 1, 'min_value': 1, 'max_value': 10 }
-    attr.interface.as_override = 'bool'
-    attr.interface.default_originate = 'bool'
-    attr.link.password = 'str'
+def pre_link_transform(topology: Box) -> None:
+  # Error if BGP module is not loaded
+  if 'bgp' not in topology.module:
+    log.error(
+      'BGP Module is not loaded.',
+      log.IncorrectValue,
+      'ebgp_utils')
 
-    # Add global, node and per-link tcp_ao option (see RFC5925 - https://datatracker.ietf.org/doc/html/rfc5925)
-    tcp_ao_algorithm = { 'type': 'str', 
-                         'valid_values': ['aes-128-cmac','hmac-sha-1',''], 
-                         'true_value': 'hmac-sha-1' } # Default to most common algo
-    attr['global'].tcp_ao = tcp_ao_algorithm
-    attr['node'].tcp_ao = tcp_ao_algorithm
-    attr['link'].tcp_ao = tcp_ao_algorithm
+'''
+post_transform hook
 
-def pre_link_transform(topology: Box) -> None:
-    # Error if BGP module is not loaded
-    if 'bgp' not in topology.module:
-        log.error(
-            'BGP Module is not loaded.',
-            log.IncorrectValue,
-            'ebgp_utils')
+As we're applying interface attributes to BGP sessions, we have to copy
+interface BGP parameters supported by this plugin into BGP neighbor parameters
+'''
 
 def post_transform(topology: Box) -> None:
-    config_name = api.get_config_name(globals())
-    # Iterate over node[x].interfaces
-    for n, ndata in topology.nodes.items():
-        for intf in ndata.interfaces:
-            if not isinstance(intf.get('bgp',None),Box):
-                continue
-            #print("LINK START *******************")
-            #print(intf)
-            #print("LINK END   *******************")
-            # Handle as_override
-            as_override = intf.get('bgp.as_override',None)
-            if as_override:
-                # Report the parameter on the BGP session, based on ifindex
-                for neigh in ndata.get('bgp', {}).get('neighbors', []):
-                    if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                        neigh.as_override = as_override
-                # Report the parameter on the BGP session (for VRF), based on ifindex
-                if 'vrf' in intf:
-                    for neigh in ndata.vrfs[intf.vrf].get('bgp', {}).get('neighbors', []):
-                        if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                            neigh.as_override = as_override
-                api.node_config(ndata,config_name)
-            # Handle allowas_in
-            allowas_in = intf.get('bgp.allowas_in',None)
-            if allowas_in:
-                # Report the parameter on the BGP session, based on ifindex
-                for neigh in ndata.get('bgp', {}).get('neighbors', []):
-                    if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                        neigh.allowas_in = int(allowas_in)
-                # Report the parameter on the BGP session (for VRF), based on ifindex
-                if 'vrf' in intf:
-                    for neigh in ndata.vrfs[intf.vrf].get('bgp', {}).get('neighbors', []):
-                        if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                            neigh.allowas_in = int(allowas_in)
-                api.node_config(ndata,config_name)
-            # Handle default_originate
-            default_originate = intf.get('bgp.default_originate',None)
-            if default_originate:
-                # Report the parameter on the BGP session, based on ifindex
-                for neigh in ndata.get('bgp', {}).get('neighbors', []):
-                    if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                        neigh.default_originate = default_originate
-                # Report the parameter on the BGP session (for VRF), based on ifindex
-                if 'vrf' in intf:
-                    for neigh in ndata.vrfs[intf.vrf].get('bgp', {}).get('neighbors', []):
-                        if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                            neigh.default_originate = default_originate
-                api.node_config(ndata,config_name)
-            # Handle bgp_password
-            bgp_password = intf.get('bgp.password',None)
-            if bgp_password:
-                # Report the parameter on the BGP session, based on ifindex
-                for neigh in ndata.get('bgp', {}).get('neighbors', []):
-                    if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                        neigh.password = bgp_password
-                # Report the parameter on the BGP session (for VRF), based on ifindex
-                if 'vrf' in intf:
-                    for neigh in ndata.vrfs[intf.vrf].get('bgp', {}).get('neighbors', []):
-                        if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
-                            neigh.password = bgp_password
-                api.node_config(ndata,config_name)
+  config_name = api.get_config_name(globals())              # Get the plugin configuration name
+
+  for n, ndata in topology.nodes.items():
+    for intf in ndata.interfaces:
+      if not isinstance(intf.get('bgp',None),Box):
+        continue
+
+      # Iterate over all link/interface attributes that have to be copied into neighbors
+      for attr in ('as_override','allowas_in','default_originate','password'):
+        attr_value = intf.bgp.get(attr,None)
+        if not attr_value:                                  # Attribute not on the interface, move on
+          continue
+
+        # Iterate over all BGP neighbors trying to find neighbors on this interface
+        for neigh in ndata.get('bgp', {}).get('neighbors', []):
+          if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
+            neigh[attr] = attr_value                        # Found the neighbor, set neighbor attribute
+            api.node_config(ndata,config_name)              # And remember that we have to do extra configuration
+
+        if 'vrf' not in intf:                               # Not a VRF interface?
+           continue                                         # ... great, move on
+
+        # Now do the same 'copy interface attribute to neighbors' thing for VRF neighbors
+        for neigh in ndata.vrfs[intf.vrf].get('bgp', {}).get('neighbors', []):
+          if neigh.ifindex == intf.ifindex and neigh.type == 'ebgp':
+            neigh[attr] = attr_value                        # Found the neighbor, set neighbor attribute
+            api.node_config(ndata,config_name)              # And remember that we have to do extra configuration