Add warning, device feature flags, and integration test

The 'not supported' warning generates a hard error that can be
disabled in case you don't care (that's what I'm using in the
integration test).

Author: ipspace

docs/module/isis.md

@@ -121,9 +121,9 @@ The IS-IS configuration module is automatically removed from a node that does no
 
 IS-IS is automatically started on all interfaces within an autonomous system (interfaces with no EBGP neighbors; see also [](routing_external)). To disable IS-IS on an intra-AS link, set the **isis** link parameter to *False* (see also [](routing_disable)).
 
-You can also set these parameters:
+You can also set these parameters on links or interfaces:
 
-* **isis.type** -- Set link type (**level-1**, **level-2** or **level-1-2**).
+* **isis.type** -- Set interface circuit type (the type of adjacency that can be established over this link -- **level-1**, **level-2** or **level-1-2**).
 * **isis.network_type** -- Set IS-IS network type. Valid values are **point-to-point** or *False* (do not set the network type). See also [Default Link Parameters](#default-link-parameters).
 * **isis.metric** or **isis.cost** -- Interface cost. Both parameters are recognized to make IS-IS configuration similar to OSPF (*metric* takes precedence over *cost*)
 * **isis.bfd** -- enable or disable BFD on individual interfaces. Like with the node-level **isis.bfd** parameter, this parameter could be a boolean value (*True* to enable BFD for all address families, *False* to disable IS-IS BFD on the interface) or a dictionary of address families, for example:

netsim/devices/eos.yml

@@ -52,11 +52,12 @@ features:
   gateway:
     protocol: [ anycast, vrrp ]
   isis:
+    circuit_type: true
+    import: [ bgp, ospf, ripv2, connected, static, vrf ]
     unnumbered:
       ipv4: true
       ipv6: true
       network: true
-    import: [ bgp, ospf, ripv2, connected, static, vrf ]
   lag:
     mlag:
       peer:

netsim/devices/frr.yml

@@ -80,6 +80,7 @@ features:
   gateway:
     protocol: [ vrrp, anycast ]
   isis:
+    circuit_type: true
     import: [ bgp, ripv2, ospf, connected, static, vrf ]
     unnumbered:
       ipv4: true

netsim/devices/ios.yml

@@ -53,6 +53,7 @@ features:
     roles: [ host, router, bridge ]
     mgmt_vrf: true
   isis:
+    circuit_type: true
     import: [ bgp, ospf, ripv2, connected, static ]
     unnumbered:
       ipv4: true

netsim/modules/isis.py

@@ -78,6 +78,7 @@ def node_post_transform(self, node: Box, topology: Box) -> None:
     if 'sr' in node.module:
       _routing.router_id(node,'isis',topology.pools)
 
+    isis_ct_intf = []
     for l in node.get('interfaces',[]):
       if _routing.external(l,'isis') or not (l.get('ipv4',False) or l.get('ipv6',False)):
         l.pop('isis',None) # Don't run IS-IS on external interfaces, or l2-only
@@ -86,6 +87,16 @@ def node_post_transform(self, node: Box, topology: Box) -> None:
         err = _routing.network_type(l,'isis',['point-to-point'])
         if err:
           log.error(f'{err}\n... node {node.name} link {l}')
+        if 'isis.type' in l and not features.isis.circuit_type:
+          isis_ct_intf.append(l.ifname)
+
+    if isis_ct_intf:
+      log.warning(
+        text=f'Device {node.device} (node {node.name}) does not support IS-IS circuit type',
+        flag='circuit_type',
+        module='isis',
+        more_data=f'Used on interface(s) {",".join(isis_ct_intf)}',
+        category=log.IncorrectAttr)
 
     _routing.igp_post_transform(node,topology,proto='isis',vrf_aware=True)
     bfd.multiprotocol_bfd_link_state(node,'isis')

tests/integration/isis/03-dual-stack.yml

@@ -8,18 +8,20 @@ module: [ isis ]
 
 defaults.interfaces.mtu: 1500
 defaults.sources.extra: [ defaults-ds.yml, ../wait_times.yml, ../warnings.yml ]
+defaults.isis.warnings.circuit_type: False
 
 groups:
   probes:
     provider: clab
-    members: [ x1, x2 ]
+    members: [ x1, x2, x3 ]
 
 isis.type: level-1-2
 
 nodes:
   dut:
   x1:
   x2:
+  x3:
 
 links:
 - dut:
@@ -28,13 +30,29 @@ links:
 - dut:
   x2:
 
+- dut:
+    isis.type: level-1
+  x3:
+
 validate:
   adj:
     description: Check IS-IS adjacencies
     wait_msg: Waiting for IS-IS adjacency process to complete
     wait: isis_adj_p2p
     nodes: [ x1, x2 ]
     plugin: isis_neighbor('dut',level='L1L2')
+  adj_x3:
+    description: Check the DUT-X3 IS-IS adjacency
+    wait_msg: Waiting for IS-IS adjacency process to complete
+    wait: isis_adj_p2p
+    nodes: [ x3 ]
+    plugin: isis_neighbor('dut')
+  adj_ct:
+    description: Check the level of DUT-X3 IS-IS adjacency
+    fail: The IS-IS adjacency is not limited by the circuit type on DUT
+    nodes: [ x3 ]
+    plugin: isis_neighbor('dut',level='L1')
+    level: warning
   pfx_v4:
     description: Check IS-IS IPv4 prefix
     wait_msg: Waiting for IS-IS SPF run