Merge pull request #20498 from yuwata/network-fix-gateway

network: fix logic for checking gateway address

src/network/networkd-nexthop.c

@@ -793,12 +793,7 @@ static bool nexthop_is_ready_to_configure(Link *link, const NextHop *nexthop) {
                 }
         }
 
-        if (nexthop->onlink <= 0 &&
-            in_addr_is_set(nexthop->family, &nexthop->gw) &&
-            !manager_address_is_reachable(link->manager, nexthop->family, &nexthop->gw))
-                return false;
-
-        return true;
+        return gateway_is_ready(link, nexthop->onlink, nexthop->family, &nexthop->gw);
 }
 
 int request_process_nexthop(Request *req) {

src/network/networkd-route.c

@@ -750,6 +750,8 @@ static bool prefix_route_address_is_reachable(const Address *a, int family, cons
 
         if (a->family != family)
                 return false;
+        if (!address_is_ready(a))
+                return false;
         if (FLAGS_SET(a->flags, IFA_F_NOPREFIXROUTE))
                 return false;
         if (in_addr_is_set(a->family, &a->in_addr_peer))
@@ -763,37 +765,34 @@ static bool prefix_route_address_is_reachable(const Address *a, int family, cons
                         FAMILY_ADDRESS_SIZE(family) * 8) > 0;
 }
 
-bool manager_address_is_reachable(Manager *manager, int family, const union in_addr_union *address) {
-        Link *link;
+static bool link_address_is_reachable(Link *link, int family, const union in_addr_union *address) {
+        Route *route;
 
-        assert(manager);
+        assert(link);
+        assert(link->manager);
         assert(IN_SET(family, AF_INET, AF_INET6));
         assert(address);
 
-        HASHMAP_FOREACH(link, manager->links_by_index) {
-                Route *route;
 
-                SET_FOREACH(route, link->routes)
-                        if (route_address_is_reachable(route, family, address))
-                                return true;
-                SET_FOREACH(route, link->routes_foreign)
-                        if (route_address_is_reachable(route, family, address))
-                                return true;
-        }
+        SET_FOREACH(route, link->routes)
+                if (route_address_is_reachable(route, family, address))
+                        return true;
+        SET_FOREACH(route, link->routes_foreign)
+                if (route_address_is_reachable(route, family, address))
+                        return true;
 
         /* If we do not manage foreign routes, then there may exist a prefix route we do not know,
          * which was created on configuring an address. Hence, also check the addresses. */
-        if (!manager->manage_foreign_routes)
-                HASHMAP_FOREACH(link, manager->links_by_index) {
-                        Address *a;
+        if (!link->manager->manage_foreign_routes) {
+                Address *a;
 
-                        SET_FOREACH(a, link->addresses)
-                                if (prefix_route_address_is_reachable(a, family, address))
-                                        return true;
-                        SET_FOREACH(a, link->addresses_foreign)
-                                if (prefix_route_address_is_reachable(a, family, address))
-                                        return true;
-                }
+                SET_FOREACH(a, link->addresses)
+                        if (prefix_route_address_is_reachable(a, family, address))
+                                return true;
+                SET_FOREACH(a, link->addresses_foreign)
+                        if (prefix_route_address_is_reachable(a, family, address))
+                                return true;
+        }
 
         return false;
 }
@@ -1689,6 +1688,22 @@ int link_request_static_routes(Link *link, bool only_ipv4) {
         return 0;
 }
 
+bool gateway_is_ready(Link *link, int onlink, int family, const union in_addr_union *gw) {
+        assert(link);
+        assert(gw);
+
+        if (onlink > 0)
+                return true;
+
+        if (!in_addr_is_set(family, gw))
+                return true;
+
+        if (family == AF_INET6 && in6_addr_is_link_local(&gw->in6))
+                return true;
+
+        return link_address_is_reachable(link, family, gw);
+}
+
 static int route_is_ready_to_configure(const Route *route, Link *link) {
         MultipathRoute *m;
         NextHop *nh = NULL;
@@ -1732,19 +1747,13 @@ static int route_is_ready_to_configure(const Route *route, Link *link) {
                         return r;
         }
 
-        if (route->gateway_onlink <= 0 &&
-            in_addr_is_set(route->gw_family, &route->gw) > 0 &&
-            !manager_address_is_reachable(link->manager, route->gw_family, &route->gw))
+        if (!gateway_is_ready(link, route->gateway_onlink, route->gw_family, &route->gw))
                 return false;
 
         ORDERED_SET_FOREACH(m, route->multipath_routes) {
                 union in_addr_union a = m->gateway.address;
                 Link *l = NULL;
 
-                if (route->gateway_onlink <= 0 &&
-                    !manager_address_is_reachable(link->manager, m->gateway.family, &a))
-                        return false;
-
                 if (m->ifname) {
                         if (link_get_by_name(link->manager, m->ifname, &l) < 0)
                                 return false;
@@ -1756,6 +1765,9 @@ static int route_is_ready_to_configure(const Route *route, Link *link) {
                 }
                 if (l && !link_is_ready_to_configure(l, true))
                         return false;
+
+                if (!gateway_is_ready(l ?: link, route->gateway_onlink, m->gateway.family, &a))
+                        return false;
         }
 
         return true;

src/network/networkd-route.h

@@ -78,8 +78,8 @@ int route_configure_handler_internal(sd_netlink *rtnl, sd_netlink_message *m, Li
 int route_remove(const Route *route, Manager *manager, Link *link);
 
 int link_has_route(Link *link, const Route *route);
-bool manager_address_is_reachable(Manager *manager, int family, const union in_addr_union *address);
 int manager_find_uplink(Manager *m, int family, Link *exclude, Link **ret);
+bool gateway_is_ready(Link *link, int onlink, int family, const union in_addr_union *gw);
 
 int link_drop_routes(Link *link);
 int link_drop_foreign_routes(Link *link);

test/test-network/conf/25-nexthop.network

@@ -38,6 +38,10 @@ Id=7
 Family=ipv6
 Blackhole=yes
 
+[NextHop]
+Id=8
+Gateway=fe80::222:4dff:ff:ff:ff:ff
+
 [NextHop]
 Gateway=192.168.5.2
 

test/test-network/conf/25-route-static.network

@@ -17,6 +17,10 @@ Destination=2001:1234:5:9fff:ff:ff:ff:ff/128
 [Route]
 Gateway=2001:1234:5:8fff:ff:ff:ff:ff
 
+[Route]
+Destination=2001:1234:5:afff:ff:ff:ff:ff/128
+Gateway=fe80::222:4dff:ff:ff:ff:ff
+
 [Route]
 Destination=149.10.124.64
 Scope=link

test/test-network/systemd-networkd-tests.py

@@ -2337,6 +2337,7 @@ class NetworkdNetworkTests(unittest.TestCase, Utilities):
         print(output)
         self.assertIn('2001:1234:5:8fff:ff:ff:ff:ff proto static', output)
         self.assertIn('2001:1234:5:8f63::1 proto kernel', output)
+        self.assertIn('2001:1234:5:afff:ff:ff:ff:ff via fe80:0:222:4dff:ff:ff:ff:ff proto static', output)
 
         print('### ip -6 route show default')
         output = check_output('ip -6 route show default')
@@ -2985,6 +2986,7 @@ class NetworkdNetworkTests(unittest.TestCase, Utilities):
             self.assertIn('id 3 dev veth99', output)
             self.assertIn('id 4 dev veth99', output)
             self.assertRegex(output, 'id 5 via 192.168.10.1 dev veth99 .*onlink')
+            self.assertIn('id 8 via fe80:0:222:4dff:ff:ff:ff:ff dev veth99', output)
             self.assertRegex(output, r'id [0-9]* via 192.168.5.2 dev veth99')
 
             output = check_output('ip nexthop list dev dummy98')