feat: Add support for blackhole/prohibit/unreachable route type

When users have BGP routing setups, it is common practice to blackhole
some less-specific routes in order to avoid routing loops, and the BGP
router might insert a more specific route dynamically afterwards.

Support prohibited and unreachable route type in the case of generated
ICMP message "administratively prohibited" and "host unreachable"
explicitly desired. Having prohibited routes to ease debugging purposes
in the remote network in conjunction with private network interconnects.
Unreachable route is quite widely used to cause a "meaningless" message
(also to end users in some cases), but here mainly on routers to make
a smaller destination prefix unreachable for different reasons, when
just having a default gateway rather a default free zone with BGP (to
effectively block smaller amounts of specific destination prefixes).

Signed-off-by: Wen Liang <liangwen12year@gmail.com>

README.md

@@ -586,13 +586,16 @@ The IP configuration supports the following options:
 
   Static route configuration can be specified via a list of routes given in the
   `route` option. The default value is an empty list. Each route is a dictionary with
-  the following entries: `network`, `prefix`, `gateway`, `metric` and `table`.
+  the following entries: `gateway`, `metric`, `network`, `prefix`, `table` and `type`.
   `network` and `prefix` specify the destination network. `table` supports both the
-  numeric table and named table. In order to specify the named table, the users have
-  to ensure the named table is properly defined in `/etc/iproute2/rt_tables` or
-  `/etc/iproute2/rt_tables.d/*.conf`.
-  Note that Classless inter-domain routing (CIDR) notation or network mask notation
-  are not supported yet.
+  numeric table and named table. In order to specify the named table, the users have to
+  ensure the named table is properly defined in `/etc/iproute2/rt_tables` or
+  `/etc/iproute2/rt_tables.d/*.conf`. The optional `type` key supports the values
+  `blackhole`, `prohibit`, and `unreachable`, see [man 8 ip-route](https://man7.org/linux/man-pages/man8/ip-route.8.html#DESCRIPTION)
+  for their definition. Routes with these types do not support a gateway. If the type
+  is not specified, the route is considered as a unicast route. Note that the classless
+  inter-domain routing(CIDR) notation or the network mask notation are not supported
+  for the `network` key.
 
 - `routing_rule`
 

examples/route_type_support.yml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: BSD-3-Clause
+---
+- name: Manage route type routes
+  hosts: all
+  tasks:
+    - name: Configure connection profile and route type routes
+      import_role:
+        name: linux-system-roles.network
+      vars:
+        network_connections:
+          - name: eth0
+            interface_name: eth0
+            state: up
+            type: ethernet
+            autoconnect: true
+            ip:
+              dhcp4: false
+              address:
+                - 198.51.100.3/26
+                - 2001:db8::2/32
+              route:
+                - network: 198.51.100.64
+                  prefix: 26
+                  gateway: 198.51.100.6
+                  metric: 4
+                  table: 30200
+                - network: 198.53.100.18
+                  prefix: 32
+                  metric: 20
+                  type: blackhole
+                  table: 30200
+                - network: 198.53.100.12
+                  prefix: 32
+                  metric: 24
+                  type: unreachable
+                  table: 30200
+                - network: 198.53.100.10
+                  prefix: 32
+                  metric: 30
+                  type: prohibit
+                  table: 30200
+                - network: 2001:db8::4
+                  prefix: 128
+                  metric: 2
+                  type: blackhole
+                  table: 30600
+                - network: 2001:db8::6
+                  prefix: 128
+                  metric: 4
+                  type: prohibit
+                  table: 30600

library/network_connections.py

@@ -1255,6 +1255,10 @@ def connection_create(self, connections, idx, connection_current=None):
                 new_route = NM.IPRoute.new(
                     r["family"], r["network"], r["prefix"], r["gateway"], r["metric"]
                 )
+                if r["type"]:
+                    NM.IPRoute.set_attribute(
+                        new_route, "type", Util.GLib().Variant("s", r["type"])
+                    )
                 if r["table"]:
                     NM.IPRoute.set_attribute(
                         new_route, "table", Util.GLib().Variant.new_uint32(r["table"])
@@ -2222,7 +2226,23 @@ def run_prepare(self):
         names = {}
         for idx, connection in enumerate(self.connections):
             self._check_ethtool_setting_support(idx, connection)
-
+            if connection.get("ip", {}):
+                for route in connection["ip"]["route"]:
+                    if route["type"]:
+                        # The special route type prohibit, blackhole and unreachable
+                        # are only supported in NM since version 1.36.0
+                        nm_support_version = "1.36.0"
+                        if not self._nm_provider.nm_support_version_cmp(
+                            nm_support_version
+                        ):
+                            self.log_fatal(
+                                idx,
+                                "route type {0} is only supported in NM since 1.36.0 "
+                                "but the current NM version is {1}".format(
+                                    route["type"],
+                                    self._nm_provider.get_client_version(),
+                                ),
+                            )
             name = connection["name"]
             if not name:
                 if not connection["persistent_state"] == "absent":

module_utils/network_lsr/argument_validator.py

@@ -674,6 +674,11 @@ def __init__(self, name, family=None, required=False):
                 ArgValidatorNum(
                     "metric", default_value=-1, val_min=-1, val_max=UINT32_MAX
                 ),
+                ArgValidatorStr(
+                    "type",
+                    default_value=None,
+                    enum_values=["blackhole", "prohibit", "unreachable"],
+                ),
                 ArgValidatorRouteTable("table"),
             ],
             default_value=None,
@@ -688,13 +693,20 @@ def _validate_post(self, value, name, result):
         result["family"] = family
 
         gateway = result["gateway"]
+        route_type = result["type"]
         if gateway is not None:
             if family != gateway["family"]:
                 raise ValidationError(
                     name,
                     "conflicting address family between network and gateway '%s'"
                     % (gateway["address"]),
                 )
+            if route_type is not None:
+                raise ValidationError(
+                    name,
+                    "a %s route can not have a gateway '%s'"
+                    % (route_type, gateway["address"]),
+                )
             result["gateway"] = gateway["address"]
 
         prefix = result["prefix"]
@@ -2607,6 +2619,14 @@ def _ipv6_is_not_configured(connection):
                         "NetworkManger until NM 1.30",
                     )
 
+        if connection["ip"]["route"]:
+            if mode == self.VALIDATE_ONE_MODE_INITSCRIPTS:
+                for route in connection["ip"]["route"]:
+                    if route["type"] is not None:
+                        raise ValidationError.from_connection(
+                            idx,
+                            "type is not supported by initscripts",
+                        )
         if connection["ip"]["routing_rule"]:
             if mode == self.VALIDATE_ONE_MODE_INITSCRIPTS:
                 raise ValidationError.from_connection(

tests/ensure_provider_tests.py

@@ -95,6 +95,11 @@
     },
     "playbooks/tests_reapply.yml": {},
     "playbooks/tests_route_table.yml": {},
+    "playbooks/tests_route_type.yml": {
+        MINIMUM_VERSION: "'1.36.0'",
+        "comment": "# NetworkManager 1.36.0 added support for special route types: \
+blackhole, prohibit and unreachable",
+    },
     "playbooks/tests_routing_rules.yml": {},
     # team interface is not supported on Fedora
     "playbooks/tests_team.yml": {

tests/playbooks/tests_route_type.yml

@@ -0,0 +1,194 @@
+# SPDX-License-Identifier: BSD-3-Clause
+---
+- name: Play for testing route types
+  hosts: all
+  vars:
+    type: veth
+    interface: ethtest0
+  tasks:
+    - name: "Set type={{ type }} and interface={{ interface }}"  # noqa name
+      set_fact:
+        type: "{{ type }}"
+        interface: "{{ interface }}"
+    - name: Include the task 'show_interfaces.yml'
+      include_tasks: tasks/show_interfaces.yml
+    - name: Include the task 'manage_test_interface.yml'
+      include_tasks: tasks/manage_test_interface.yml
+      vars:
+        state: present
+    - name: Include the task 'assert_device_present.yml'
+      include_tasks: tasks/assert_device_present.yml
+
+    - name: Configure connection profile and specify the route types in
+        static routes
+      import_role:
+        name: linux-system-roles.network
+      vars:
+        network_connections:
+          - name: "{{ interface }}"
+            interface_name: "{{ interface }}"
+            state: up
+            type: ethernet
+            autoconnect: true
+            ip:
+              dhcp4: false
+              address:
+                - 198.51.100.3/26
+                - 2001:db8::2/32
+              route:
+                - network: 198.51.100.64
+                  prefix: 26
+                  gateway: 198.51.100.6
+                  metric: 4
+                  table: 30200
+                - network: 198.53.100.18
+                  prefix: 32
+                  metric: 20
+                  type: blackhole
+                  table: 30200
+                - network: 198.53.100.10
+                  prefix: 32
+                  metric: 30
+                  type: prohibit
+                  table: 30200
+                - network: 198.53.100.12
+                  prefix: 32
+                  metric: 24
+                  type: unreachable
+                  table: 30200
+                - network: 2001:db8::4
+                  prefix: 128
+                  metric: 2
+                  type: blackhole
+                  table: 30600
+                - network: 2001:db8::6
+                  prefix: 128
+                  metric: 4
+                  type: prohibit
+                  table: 30600
+
+    - name: Get the routes from the route table 30200
+      command: ip route show table 30200
+      register: route_table_30200
+      changed_when: false
+
+    - name: Get the routes from the route table 30600
+      command: ip -6 route show table 30600
+      register: route_table_30600
+      changed_when: false
+
+    - name: Assert that the route table 30200 contains the specified route
+      assert:
+        that:
+          - route_table_30200.stdout is search("198.51.100.64/26 via
+            198.51.100.6 dev ethtest0 proto static metric 4")
+          - route_table_30200.stdout is search("blackhole 198.53.100.18
+            proto static scope link metric 20")
+          - route_table_30200.stdout is search("prohibit 198.53.100.10
+            proto static scope link metric 30")
+          - route_table_30200.stdout is search("unreachable 198.53.100.12
+            proto static scope link metric 24")
+        msg: "the route table 30200 does not exist or does not contain the
+          specified route"
+
+    - name: Assert that the route table 30600 contains the specified route
+      assert:
+        that:
+          - route_table_30600.stdout is search("blackhole 2001:db8::4
+            dev lo proto static metric 2 pref medium")
+          - route_table_30600.stdout is search("prohibit 2001:db8::6
+            dev lo proto static metric 4 pref medium")
+        msg: "the route table 30600 does not exist or does not contain the
+          specified route"
+
+    - name: Removing some routes
+      import_role:
+        name: linux-system-roles.network
+      vars:
+        network_connections:
+          - name: "{{ interface }}"
+            interface_name: "{{ interface }}"
+            state: up
+            type: ethernet
+            autoconnect: true
+            ip:
+              dhcp4: false
+              address:
+                - 198.51.100.3/26
+                - 2001:db8::2/32
+              route:
+                - network: 198.51.100.64
+                  prefix: 26
+                  gateway: 198.51.100.6
+                  metric: 4
+                  table: 30200
+                - network: 2001:db8::4
+                  prefix: 128
+                  metric: 2
+                  type: blackhole
+                  table: 30600
+                - network: 2001:db8::6
+                  prefix: 128
+                  metric: 4
+                  type: prohibit
+                  table: 30600
+
+    - name: Get the routes from the route table 30200 after removing routes
+      command: ip route show table 30200
+      register: table_30200
+      changed_when: false
+
+    - name: Get the routes from the route table 30600 after removing routes
+      command: ip -6 route show table 30600
+      register: table_30600
+      changed_when: false
+
+    - name: Assert that the route table 30200 contains the specified unicast
+        route
+      assert:
+        that:
+          - route_table_30200.stdout is search("198.51.100.64/26 via
+            198.51.100.6 dev ethtest0 proto static metric 4")
+        msg: "the route table 30200 does not exist or does not contain the
+          specified unicast route"
+
+    - name: Assert that the route table 30200 does not contain the type routes
+      assert:
+        that:
+          - table_30200.stdout is not search("blackhole 198.53.100.18
+            proto static scope link metric 20")
+          - table_30200.stdout is not search("prohibit 198.53.100.10
+            proto static scope link metric 30")
+          - table_30200.stdout is not search("unreachable 198.53.100.12
+            proto static scope link metric 24")
+        msg: "the route table 30200 contains the type routes"
+
+    - name: Assert that the route table 30600 still contains the type routes
+      assert:
+        that:
+          - table_30600.stdout is search("blackhole 2001:db8::4
+            dev lo proto static metric 2 pref medium")
+          - table_30600.stdout is search("prohibit 2001:db8::6
+            dev lo proto static metric 4 pref medium")
+        msg: "the route table 30600 does not exist or does not contain the
+          type routes"
+
+- name: Import the playbook 'down_profile+delete_interface.yml'
+  import_playbook: down_profile+delete_interface.yml
+  vars:
+    profile: "{{ interface }}"
+# FIXME: assert profile/device down
+- name: Import the playbook 'remove_profile.yml'
+  import_playbook: remove_profile.yml
+  vars:
+    profile: "{{ interface }}"
+- name: Assert device and profile are absent
+  hosts: all
+  tasks:
+    - name: Include the task 'assert_profile_absent.yml'
+      include_tasks: tasks/assert_profile_absent.yml
+      vars:
+        profile: "{{ interface }}"
+    - name: Include the task 'assert_device_absent.yml'
+      include_tasks: tasks/assert_device_absent.yml
+...