Merge pull request #17544 from anlancs/zebra/fix-plug-interface

zebra: fix wrong nexthop status for kernel routes

tests/topotests/zebra_multiple_connected/r1/ip_route_kernel_interface_down.json

@@ -0,0 +1,20 @@
+{
+  "5.5.6.7/32":[
+    {
+      "prefix":"5.5.6.7/32",
+      "prefixLen":32,
+      "protocol":"kernel",
+      "vrfName":"default",
+      "internalFlags":0,
+      "internalNextHopNum":1,
+      "internalNextHopActiveNum":0,
+      "nexthops":[
+        {
+          "flags":0,
+          "interfaceName":"r1-eth2"
+        }
+      ]
+
+    }
+  ]
+}

tests/topotests/zebra_multiple_connected/r1/ip_route_kernel_interface_up.json

@@ -0,0 +1,21 @@
+{
+  "5.5.6.7/32":[
+    {
+      "prefix":"5.5.6.7/32",
+      "prefixLen":32,
+      "protocol":"kernel",
+      "vrfName":"default",
+      "internalFlags":8,
+      "internalNextHopNum":1,
+      "internalNextHopActiveNum":1,
+      "nexthops":[
+        {
+          "flags":3,
+          "fib":true,
+          "interfaceName":"r1-eth2",
+          "active":true
+        }
+      ]
+    }
+  ]
+}

tests/topotests/zebra_multiple_connected/test_zebra_multiple_connected.py

@@ -65,6 +65,9 @@ def build_topo(tgen):
     switch.add_link(tgen.gears["r2"])
     switch.add_link(tgen.gears["r3"])
 
+    # Create a p2p connection between r1 and r2
+    tgen.add_link(tgen.gears["r1"], tgen.gears["r2"])
+
 
 #####################################################
 ##
@@ -222,6 +225,50 @@ def test_zebra_kernel_route_blackhole_add():
     result, _ = topotest.run_and_expect(test_func, None, count=20, wait=1)
     assert result, "Blackhole Route should have not been removed\n{}".format(_)
 
+def test_zebra_kernel_route_interface_linkdown():
+    "Test that a kernel routes should be affected by interface change"
+
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    router = tgen.gears["r1"]
+    router.run("ip route add 5.5.6.7/32 via 10.0.1.66 dev r1-eth2")
+
+    kernel = "{}/{}/ip_route_kernel_interface_up.json".format(CWD, router.name)
+    expected = json.loads(open(kernel).read())
+
+    test_func = partial(
+            topotest.router_json_cmp, router, "show ip route 5.5.6.7/32 json", expected
+            )
+    result, _ = topotest.run_and_expect(test_func, None, count=20, wait=1)
+    assert result, "Kernel Route should be selected:\n{}".format(_)
+
+    # link down
+    router2 = tgen.gears["r2"]
+    router2.run("ip link set dev r2-eth2 down")
+
+    kernel = "{}/{}/ip_route_kernel_interface_down.json".format(CWD, router.name)
+    expected = json.loads(open(kernel).read())
+
+    test_func = partial(
+        topotest.router_json_cmp, router, "show ip route 5.5.6.7/32 json", expected
+    )
+    result, _ = topotest.run_and_expect(test_func, None, count=20, wait=1)
+    assert result, "Kernel Route should not be selected:\n{}".format(_)
+
+    # link up
+    router2 = tgen.gears["r2"]
+    router2.run("ip link set dev r2-eth2 up")
+
+    kernel = "{}/{}/ip_route_kernel_interface_up.json".format(CWD, router.name)
+    expected = json.loads(open(kernel).read())
+
+    test_func = partial(
+            topotest.router_json_cmp, router, "show ip route 5.5.6.7/32 json", expected
+            )
+    result, _ = topotest.run_and_expect(test_func, None, count=20, wait=1)
+    assert result, "Kernel Route should be selected:\n{}".format(_)
 
 if __name__ == "__main__":
     args = ["-s"] + sys.argv[1:]

zebra/interface.c

@@ -972,6 +972,8 @@ void if_up(struct interface *ifp, bool install_connected)
 	event_ignore_late_timer(zif->speed_update);
 
 	if_addr_wakeup(ifp);
+
+	rib_update_handle_vrf_all(RIB_UPDATE_KERNEL, ZEBRA_ROUTE_KERNEL);
 }
 
 /* Interface goes down.  We have to manage different behavior of based

zebra/zebra_nhg.c

@@ -2648,7 +2648,7 @@ static unsigned nexthop_active_check(struct route_node *rn,
 
 		ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
 
-		if (ifp && ifp->vrf->vrf_id == vrf_id && if_is_up(ifp)) {
+		if (ifp && ifp->vrf->vrf_id == vrf_id && if_is_up(ifp) && if_is_operative(ifp)) {
 			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
 			goto skip_check;
 		}

zebra/zebra_rib.c

@@ -1421,7 +1421,7 @@ static void rib_process(struct route_node *rn)
 		rib_process_update_fib(zvrf, rn, old_fib, new_fib);
 	else if (new_fib)
 		rib_process_add_fib(zvrf, rn, new_fib);
-	else if (old_fib)
+	else if (old_fib && !RIB_SYSTEM_ROUTE(old_fib))
 		rib_process_del_fib(zvrf, rn, old_fib);
 
 	/* Remove all RE entries queued for removal */