network/ndisc: do not set per-route MTU and hop limit

Setting MTU announced in RA message to routes is problematic, as the
value may be larger than the device MTU (IFLA_MTU), and in such case the
route cannot be used.

These two properties are now set per-interface, and gracefully handled
such invalid cases. Hence not necessary to set them to each route.

Follow-up for #32195.

diff --git a/src/network/networkd-ndisc.c b/src/network/networkd-ndisc.c
index f0c58e8842b7d7ba5c4372b34f5d12c1d96af46f..73a88bd4096d428e192dbcbe1bd0e6ff1cce6f31 100644 (file)
--- a/src/network/networkd-ndisc.c
+++ b/src/network/networkd-ndisc.c
@@ -179,8 +179,6 @@ static void ndisc_set_route_priority(Link *link, Route *route) {
 
 static int ndisc_request_route(Route *route, Link *link, sd_ndisc_router *rt) {
         struct in6_addr router;
-        uint8_t hop_limit = 0;
-        uint32_t mtu = 0;
         bool is_new;
         int r;
 
@@ -194,30 +192,13 @@ static int ndisc_request_route(Route *route, Link *link, sd_ndisc_router *rt) {
         if (r < 0)
                 return r;
 
-        if (link->network->ndisc_use_mtu) {
-                r = sd_ndisc_router_get_mtu(rt, &mtu);
-                if (r < 0 && r != -ENODATA)
-                        return log_link_warning_errno(link, r, "Failed to get MTU from RA: %m");
-        }
-
-        if (link->network->ndisc_use_hop_limit) {
-                r = sd_ndisc_router_get_hop_limit(rt, &hop_limit);
-                if (r < 0 && r != -ENODATA)
-                        return log_link_warning_errno(link, r, "Failed to get hop limit from RA: %m");
-        }
-
         route->source = NETWORK_CONFIG_SOURCE_NDISC;
         route->provider.in6 = router;
         if (!route->table_set)
                 route->table = link_get_ndisc_route_table(link);
         if (!route->protocol_set)
                 route->protocol = RTPROT_RA;
-        r = route_metric_set(&route->metric, RTAX_MTU, mtu);
-        if (r < 0)
-                return r;
-        r = route_metric_set(&route->metric, RTAX_HOPLIMIT, hop_limit);
-        if (r < 0)
-                return r;
+
         r = route_metric_set(&route->metric, RTAX_QUICKACK, link->network->ndisc_quickack);
         if (r < 0)
                 return r;

diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 3732e7a0d7ec0e231bc937a3e1cf15b34e5cdb04..aced559f04823fe1c9a4401cb1cc6e514bea7c49 100755 (executable)
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -5668,15 +5668,6 @@ class NetworkdRATests(unittest.TestCase, Utilities):
         self.assertIn('2002:da8:1:0:b47e:7975:fc7a:7d6e', output)
         self.assertIn('2002:da8:2:0:f689:561a:8eda:7443', output)
 
-    def check_router_hop_limit(self, hop_limit):
-        self.wait_route('client', rf'default via fe80::1034:56ff:fe78:9a99 proto ra .* hoplimit {hop_limit}', ipv='-6', timeout_sec=10)
-
-        output = check_output('ip -6 route show dev client default via fe80::1034:56ff:fe78:9a99')
-        print(output)
-        self.assertIn(f'hoplimit {hop_limit}', output)
-
-        self.check_ipv6_sysctl_attr('client', 'hop_limit', f'{hop_limit}')
-
     def test_router_hop_limit(self):
         copy_network_unit('25-veth-client.netdev',
                           '25-veth-router.netdev',
@@ -5686,18 +5677,24 @@ class NetworkdRATests(unittest.TestCase, Utilities):
                           '25-veth-router-hop-limit.network',
                           '25-bridge99.network')
         start_networkd()
-        self.wait_online('client-p:enslaved',
+        self.wait_online('client:routable', 'client-p:enslaved',
                          'router:degraded', 'router-p:enslaved',
                          'bridge99:routable')
 
-        self.check_router_hop_limit(42)
+        self.check_ipv6_sysctl_attr('client', 'hop_limit', '42')
 
         with open(os.path.join(network_unit_dir, '25-veth-router-hop-limit.network'), mode='a', encoding='utf-8') as f:
             f.write('\n[IPv6SendRA]\nHopLimit=43\n')
 
         networkctl_reload()
 
-        self.check_router_hop_limit(43)
+        for _ in range(20):
+            output = read_ipv6_sysctl_attr('client', 'hop_limit')
+            if output == '43':
+                break
+            time.sleep(0.5)
+
+        self.check_ipv6_sysctl_attr('client', 'hop_limit', '43')
 
     def test_router_preference(self):
         copy_network_unit('25-veth-client.netdev',