Implement dual-stack and VRF-aware bgp.originate attribute

Author: ipspace

netsim/devices/none.yml

@@ -23,10 +23,12 @@ group_vars:
 features:
   bfd: True
   bgp:
+    activate_af: True
+    advertise: True
+    aggregate: true
     local_as: True
     vrf_local_as: True
     local_as_ibgp: True
-    activate_af: True
     ipv6_lla: True
     rfc8950: True
     bandwidth: True
@@ -46,7 +48,6 @@ features:
     timers: True
     import: [ ospf, isis, ripv2, connected, static, vrf ]
     confederation: True
-    aggregate: true
   dhcp:
     client:
       ipv4: true

netsim/extra/bgp.originate/defaults.yml

@@ -1,17 +1,19 @@
 from box import Box
 
-from netsim.augment import links
+from netsim.augment import devices, links
 from netsim.data import get_box
+from netsim.utils import log
 
 _requires    = [ 'bgp' ]
 
 """
 Have to complete the fix of bgp.originate attribute (can't do everything through the settings)
 """
 def init(topology: Box) -> None:
-  o_dict = topology.defaults.bgp.attributes.node.originate
-  for kw in ('use','named','type'):
-    o_dict._subtype.pop(kw,None)
+  log.warning(
+        text='The functionality of the bgp.originate plugin is now available in the BGP module',
+        module='bgp',
+        flag='obsolete')
 
 def post_node_transform(topology: Box) -> None:
   for n, ndata in topology.nodes.items():
@@ -22,6 +24,15 @@ def post_node_transform(topology: Box) -> None:
     if not o_list:
       continue
 
+    features = devices.get_device_features(ndata,topology.defaults)
+    has_advertise = features.get('bgp.advertise',False)
+    originate_v2  = has_advertise and features.get('routing.static.discard',False)
+    if originate_v2:
+      continue
+
+    # The old bgp.plugin processing is still done for the devices that cannot handle bgp.advertise
+    # or discard static routes
+    #
     for o_idx,o_entry in enumerate(o_list):                 # Iterate over entries in originate list
       o_link = get_box({                                    # Create a loopback link for each originate entry
                  'interfaces': [ { 'node': n }],

netsim/extra/bgp.originate/plugin.py

@@ -601,11 +601,73 @@ def bgp_build_advertise_list(node: Box) -> None:
     list_name = 'bgp.advertise' if 'vrf' not in intf else f'vrfs.{intf.vrf}.bgp.advertise'
     data.append_to_list(node,list_name,af_data)   # And append prefix data to the list
 
-  if 'originate' in node.bgp:                     # Next, append originate data to the advertise list
-    for o_pfx in node.bgp.originate:
-      # Convert old-style data (IPv4 string) into prefix
-      af_data = o_pfx if isinstance(o_pfx,Box) else {'ipv4': o_pfx }
-      data.append_to_list(node,'bgp.advertise',af_data)
+"""
+bgp_process_originate:
+
+* Check the device support for dual-stack and VRF 'bgp.originate' attribute
+* Append prefixes from 'bgp.originate' list to 'bgp.advertise' list
+* Convert 'bgp.originate' list to a list of IPv4-only prefixes for legacy devices
+"""
+DISCARD_NH = data.get_box({'nexthop.discard': True})
+
+def bgp_process_originate(node: Box, topology: Box) -> None:
+  global DISCARD_NH
+  features = devices.get_device_features(node,topology.defaults)
+
+  # Second-generation BGP route origination needs advertisement of routing table prefixes
+  # and discard static routes
+  #
+  # VRF BGP route origination needs VRF static routes
+  #
+  has_advertise = features.get('bgp.advertise',False)
+  originate_v2  = has_advertise and features.get('routing.static.discard',False)
+  originate_vrf = originate_v2 and features.get('routing.static.vrf',False)
+  has_routing   = 'routing' in node.module
+
+  for (bgp_data,_,vname) in _rp_utils.rp_data(node,'bgp'):
+    if 'originate' not in bgp_data:               # No prefix origination? Nice, move on.
+      continue
+
+    if vname and not originate_vrf:
+      log.error(
+        f'device {node.device} (node {node.name}) does not support VRF bgp.originate attribute',
+        category=log.IncorrectAttr,
+        module='bgp')
+      continue
+
+    if originate_v2:                              # Handle next-generation BGP route origination
+      #
+      # The second-generation BGP origination append bgp.originate attribute to bgp.advertise
+      # list and creates corresponding discard static routes
+      #
+      for pfx in bgp_data.originate:
+        data.append_to_list(bgp_data,'advertise',pfx)       # Append originate prefix to advertise list
+        sr_data = DISCARD_NH + pfx                          # This will create a new object with discard NH
+        if vname:                                           # If needed, set the VRF name in static route
+          sr_data.vrf = vname
+        data.append_to_list(node,'routing.static',sr_data)  # Add discard static route to node data
+        if not has_routing:                                 # If needed, add routing module
+          data.append_to_list(node,'module','routing')
+          has_routing = True
+
+      bgp_data.pop('originate',None)                        # The bgp.originate attribute has been processed
+
+    else:                                         # The device can do only old-style BGP route origination
+      originate_list = []
+      for pfx in bgp_data.originate:              # Rebuild bgp.originate into old format
+        # bgp.advertise attribute could be ignored, but doing this does not hurt anyone
+        # plus we need it for devices that support bgp.advertise but not discard routes
+        #
+        data.append_to_list(bgp_data,'advertise',pfx)
+        if 'ipv6' in pfx:                         # Old bgp.originate implementations were IPv4 only
+          log.error(
+            f'device {node.device} (node {node.name}) cannot use bgp.originate with IPv6 BGP prefixes',
+            category=log.IncorrectValue,
+            module='bgp')
+          return
+        elif 'ipv4' in pfx:                       # Save IPv4 prefix (if it exists) into the old-style
+          originate_list.append(pfx['ipv4'])      # originate list
+      bgp_data.originate = originate_list         # ... and replace bgp.originate attribute
 
 """
 bgp_set_originate_af: set bgp[af] flags based on prefixes that should be originated
@@ -615,33 +677,12 @@ def bgp_set_originate_af(node: Box, topology: Box) -> None:
   if 'bgp' not in node:                                     # Safeguard: skip non-BGP nodes
     return
 
-  if node.get('bgp.originate',[]):                          # bgp.originate attribute implies IPv4 is active
-    node.bgp.ipv4 = True
-    pfxs = topology.get('prefix',{})
-    for o_idx,o_value in enumerate(node.bgp.originate):     # Also, replace named prefixes with IPv4 values
-      if o_value in pfxs:
-        if 'ipv4' not in pfxs[o_value]:
-          log.error(
-            f'Named prefix {o_value} used in bgp.originate in node {node.name} must have IPv4 component',
-            category=log.MissingValue,
-            module='bgp')
-          continue
-        node.bgp.originate[o_idx] = pfxs[o_value].ipv4
-
+  advertise_list = node.get('bgp.advertise',[])             # Get the list of advertised prefixes
   for af in ['ipv4','ipv6']:
     if node.get(f'bgp.{af}',False):                         # No need for further checks if the AF flag is already set
       continue
-
-    if node.get('bgp.advertise_loopback',True):             # If the router advertises its loopback prefix
-      if af in node.get('loopback',{}):                     # ... do the AF checks on loopback interface
-        node.bgp[af] = True
-        continue
-
-    for intf in node.get("interfaces",[]):                  # No decision yet, iterate over all interfaces
-      if af in intf and intf[af]:                           # Is the address family active on the interface?
-        if intf.get('bgp.advertise',False):                 # Is the interface prefix advertised in BGP?
-          if not 'vrf' in intf:                             # The AF fix is only required for global interfaces
-            node.bgp[af] = True                             # ... the stars have aligned, set the BGP AF flag
+    if any([ pfx for pfx in advertise_list if af in pfx]):  # Do we advertise any prefix with that AF?
+      node.bgp[af] = True
 
 """
 process_as_list:
@@ -967,12 +1008,13 @@ def node_post_transform(self, node: Box, topology: Box) -> None:
       log.fatal(f"Internal error: node {node.name} has BGP module enabled but no BGP parameters","bgp")
       return
     build_bgp_sessions(node,topology)
+    check_advertise_data(node,topology)
     bgp_set_advertise(node,topology)
-    bgp_set_originate_af(node,topology)
+    bgp_process_originate(node,topology)
     _routing.remove_vrf_routing_blocks(node,'bgp')
     bgp_transform_community_list(node,topology)
     _routing.check_vrf_protocol_support(node,'bgp',None,'bgp',topology)
     _routing.process_imports(node,'bgp',topology,global_vars.get_const('vrf_igp_protocols',['connected']))
-    check_advertise_data(node,topology)
     sanitize_bgp_data(node)
     bgp_build_advertise_list(node)
+    bgp_set_originate_af(node,topology)

netsim/modules/bgp.py

@@ -89,9 +89,7 @@ attributes:
     rr_cluster_id: { copy: global }
     rr_mesh: { copy: global }
     advertise: bgp_prefix_list
-    originate:
-      type: list
-      _subtype: { type: ipv4, use: subnet_prefix, named: True }
+    originate: bgp_prefix_list
     advertise_loopback: { copy: global }
     sessions: { copy: global }
     activate: { copy: global }
@@ -103,6 +101,7 @@ attributes:
   vrf:
     router_id: { type: ipv4, use: id }
     advertise: bgp_prefix_list
+    originate: bgp_prefix_list
     import: _r_import
   node_copy: [ local_as, replace_global_as ]
   link:

netsim/modules/bgp.yml

@@ -87,12 +87,12 @@ def clear_bgp_session(node: Box, ngb: Box) -> None:
 '''
 def rp_data(node: Box, proto: str, select: list = ['global','vrf']) -> typing.Generator:
   if 'global' in select:
-    if proto in node:
+    if node.get(proto,None):
       yield(node[proto],[ intf for intf in node.interfaces if proto in intf ],None)
 
   if 'vrf' in select:
     for vname,vdata in node.get('vrfs',{}).items():
-      if proto in vdata:
+      if vdata.get(proto,None):
         yield(vdata[proto],vdata[proto].get('interfaces',[]),vname)
 
 '''

netsim/utils/routing.py

@@ -199,9 +199,6 @@ nodes:
       ipv4: true
       neighbors: []
       next_hop_self: true
-      originate:
-      - 10.1.0.0/24
-      - 0.0.0.0/0
       router_id: 10.0.0.3
     box: arista/veos
     device: eos
@@ -219,9 +216,20 @@ nodes:
       ipv4: 192.168.121.103
       mac: ca:fe:00:03:00:00
     module:
+    - routing
     - bgp
     name: nl1
     role: router
+    routing:
+      static:
+      - ipv4: 10.1.0.0/24
+        nexthop:
+          discard: true
+          idx: 0
+      - ipv4: 0.0.0.0/0
+        nexthop:
+          discard: true
+          idx: 0
   nl2:
     af:
       ipv4: true

tests/topology/expected/bgp-af-rt-929.yml

@@ -116,8 +116,8 @@ nodes:
       ipv4: true
     bgp:
       advertise:
-      - ipv4: 10.0.0.1/32
       - ipv4: 172.42.42.0/24
+      - ipv4: 10.0.0.1/32
       advertise_loopback: true
       as: 65000
       community:
@@ -164,8 +164,6 @@ nodes:
         name: x1
         type: ebgp
       next_hop_self: true
-      originate:
-      - 172.42.42.0/24
       router_id: 10.0.0.42
     box: none
     device: none
@@ -250,6 +248,7 @@ nodes:
       mac: ca:fe:00:01:00:00
     module:
     - vlan
+    - routing
     - ospf
     - bgp
     mtu: 1500
@@ -264,6 +263,12 @@ nodes:
         kind: regular
       router_id: 10.0.0.42
     router_id: 10.0.0.42
+    routing:
+      static:
+      - ipv4: 172.42.42.0/24
+        nexthop:
+          discard: true
+          idx: 0
     vlan:
       max_bridge_group: 1
     vlans:
@@ -344,10 +349,15 @@ nodes:
     mtu: 1500
     name: x1
   x2:
+    _features:
+      routing:
+        static:
+          discard: false
     af:
       ipv4: true
     bgp:
       advertise:
+      - ipv4: 172.42.4.0/24
       - ipv4: 172.42.2.0/24
       advertise_loopback: true
       as: 65101
@@ -386,6 +396,8 @@ nodes:
         rr_client: true
         type: localas_ibgp
       next_hop_self: true
+      originate:
+      - 172.42.4.0/24
       router_id: 172.42.2.1
     box: none
     device: none
@@ -451,12 +463,15 @@ nodes:
         kind: regular
       router_id: 172.42.2.1
   x3:
+    _features:
+      bgp:
+        advertise: false
     af:
       ipv4: true
     bgp:
       advertise:
-      - ipv4: 10.0.0.4/32
       - ipv4: 172.42.3.0/24
+      - ipv4: 10.0.0.4/32
       advertise_loopback: true
       as: 65000
       community:

tests/topology/expected/bgp-ibgp-localas.yml

@@ -142,6 +142,8 @@ nodes:
       ipv6: true
     bgp:
       advertise:
+      - ipv4: 10.42.42.0/24
+        ipv6: 2001:db8:cafe:1::/64
       - ipv4: 10.0.0.1/32
         ipv6: 2001:db8:0:1::/64
       advertise_loopback: true
@@ -323,8 +325,16 @@ nodes:
       ipv4: 192.168.121.101
       mac: ca:fe:00:01:00:00
     module:
+    - routing
     - bgp
     name: test
+    routing:
+      static:
+      - ipv4: 10.42.42.0/24
+        ipv6: 2001:db8:cafe:1::/64
+        nexthop:
+          discard: true
+          idx: 0
   x1:
     af:
       ipv4: true

tests/topology/expected/bgp-unnumbered-dual-stack.yml

@@ -27,8 +27,11 @@ nodes:
   x2:
     bgp.as: 65101
     loopback.ipv4: 172.42.2.1/24
+    bgp.originate: 172.42.4.0/24
+    _features.routing.static.discard: False
   x3:
     bgp.originate: 172.42.3.0/24
+    _features.bgp.advertise: False
   x4:
     bgp.as: 65101
     loopback.ipv4: 172.42.4.1/24