[posix] add external routes to kernel on POSIX (#6782)

This is helpful when POSIX kernel is handling a packet at the thread
TUN device.

tests/scripts/thread-cert/border_router/test_external_route.py

@@ -0,0 +1,168 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2021, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS'
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+import logging
+import unittest
+
+import ipaddress
+import config
+import thread_cert
+
+# Test description:
+#   This test verifies that when external routes are changed in Network Data, a
+#   border router will make according updates to routes at the linux kernel.
+#
+# Topology:
+#    ----------------(eth)----------------------
+#           |                  |          |
+#          BR1 (Leader) ----- BR2       HOST
+#           |                  |
+#         ROUTER1             ROUTER2
+
+BR1 = 1
+BR2 = 2
+ROUTER1 = 3
+ROUTER2 = 4
+HOST = 5
+
+ROUTE1 = '2402:1234:1234:1234::/64'
+
+
+class MultiBorderRouters(thread_cert.TestCase):
+    USE_MESSAGE_FACTORY = False
+
+    TOPOLOGY = {
+        BR1: {
+            'name': 'BR_1',
+            'allowlist': [BR2, ROUTER1],
+            'is_otbr': True,
+            'version': '1.2',
+        },
+        BR2: {
+            'name': 'BR_2',
+            'allowlist': [BR1, ROUTER2],
+            'is_otbr': True,
+            'version': '1.2',
+        },
+        ROUTER1: {
+            'name': 'Router_1',
+            'allowlist': [BR1],
+            'version': '1.2',
+        },
+        ROUTER2: {
+            'name': 'Router_2',
+            'allowlist': [BR2],
+            'version': '1.2',
+        },
+        HOST: {
+            'name': 'Host',
+            'is_host': True,
+        }
+    }
+
+    def test(self):
+        br1 = self.nodes[BR1]
+        br2 = self.nodes[BR2]
+        router1 = self.nodes[ROUTER1]
+        router2 = self.nodes[ROUTER2]
+        host = self.nodes[HOST]
+
+        br1.start()
+        self.simulator.go(5)
+        self.assertEqual('leader', br1.get_state())
+
+        br2.start()
+        self.simulator.go(5)
+        self.assertEqual('router', br2.get_state())
+
+        router1.start()
+        router2.start()
+        host.start()
+        self.simulator.go(5)
+        self.assertEqual('router', router1.get_state())
+        self.assertEqual('router', router2.get_state())
+
+        # Manually add ROUTE1 at BR1
+        br1.add_route(ROUTE1)
+        br1.register_netdata()
+
+        # BRs has installed all external routes in their kernels respectively
+        netdata = br1.get_netdata()
+        br1_kernel_routes = self.get_routes_from_kernel(br1)
+        for route in self.get_routes_from_netdata(netdata, br1.get_addr16()):
+            self.assertIn(route, br1_kernel_routes)
+        br2_kernel_routes = self.get_routes_from_kernel(br2)
+        for route in self.get_routes_from_netdata(netdata, br2.get_addr16()):
+            self.assertIn(route, br2_kernel_routes)
+
+        # ROUTE1 has been installed in BR2 but not BR1
+        self.assertNotIn(ipaddress.IPv6Network(ROUTE1), br1_kernel_routes)
+        self.assertIn(ipaddress.IPv6Network(ROUTE1), br2_kernel_routes)
+
+        # Remove ROUTE1
+        br1.remove_route(ROUTE1)
+        br1.register_netdata()
+
+        # Verify that external routes are still in kernel routes
+        netdata = br1.get_netdata()
+        br1_kernel_routes = self.get_routes_from_kernel(br1)
+        for route in self.get_routes_from_netdata(netdata, br1.get_addr16()):
+            self.assertIn(route, br1_kernel_routes)
+        br2_kernel_routes = self.get_routes_from_kernel(br2)
+        for route in self.get_routes_from_netdata(netdata, br2.get_addr16()):
+            self.assertIn(route, br2_kernel_routes)
+
+        # ROUTE1 has been removed from kernel routes
+        self.assertNotIn(ipaddress.IPv6Network(ROUTE1), br1_kernel_routes)
+        self.assertNotIn(ipaddress.IPv6Network(ROUTE1), br2_kernel_routes)
+
+        br2.bash('ip link set eth0 down')
+        self.simulator.go(10)
+
+        # HOST pings BR2's OMR, the ping should succeed
+        self.assertTrue(host.ping_ether(br2.get_ip6_address(address_type=config.ADDRESS_TYPE.OMR)[0]))
+
+    def get_routes_from_netdata(self, netdata, exclude_rloc16):
+        routes = []
+        for entry in netdata['Routes']:
+            items = entry.split()
+            prefix = items[0]
+            rloc16 = int(items[-1], 16)
+            if rloc16 != exclude_rloc16:
+                routes.append(ipaddress.IPv6Network(prefix))
+        return routes
+
+    def get_routes_from_kernel(self, br):
+        routes = []
+        for entry in br.bash('ip -6 -d route list dev wpan0'):
+            routes.append(ipaddress.IPv6Network(entry.split()[1]))
+        return routes
+
+
+if __name__ == '__main__':
+    unittest.main()