src/nm.c: set the MTU even though we also specify it in systemd-networkd for consumption by udev. NetworkManager will try to set it and might otherwise default to the wrong value.

3 files changed, 107 insertions, 2 deletions

diff --git a/debian/changelog b/debian/changelog
index bbaae8c..e1dbcd2 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -5,6 +5,9 @@ nplan (0.25) UNRELEASED; urgency=medium
   * tests/integration.py: clean up after br0 in networkd's test_bridge_mac; as
     the remaining interface and udev configuration can confuse NetworkManager
     now that it seems to manage random devices it did not create again.
+  * src/nm.c: set the MTU even though we also specify it in systemd-networkd
+    for consumption by udev. NetworkManager will try to set it and might
+    otherwise default to the wrong value.
 
  -- Mathieu Trudel-Lapierre <cyphermox@ubuntu.com>  Tue, 11 Jul 2017 13:43:21 -0400
 
diff --git a/src/nm.c b/src/nm.c
index 6921fee..d8db582 100644
--- a/src/nm.c
+++ b/src/nm.c
@@ -305,6 +305,9 @@ write_nm_conf_access_point(net_definition* def, const char* rootdir, const wifi_
         if (def->set_mac) {
             g_string_append_printf(link_str, "cloned-mac-address=%s\n", def->set_mac);
         }
+        if (def->mtubytes) {
+            g_string_append_printf(link_str, "mtu=%d\n", def->mtubytes);
+        }
 
         if (link_str->len > 0) {
             switch (def->type) {
@@ -317,8 +320,22 @@ write_nm_conf_access_point(net_definition* def, const char* rootdir, const wifi_
 
         g_string_free(link_str, TRUE);
     } else {
-        if (def->set_mac)
-            g_string_append_printf(s, "\n[802-3-ethernet]\ncloned-mac-address=%s\n", def->set_mac);
+        GString *link_str = NULL;
+
+        link_str = g_string_new(NULL);
+
+        if (def->set_mac) {
+            g_string_append_printf(link_str, "cloned-mac-address=%s\n", def->set_mac);
+        }
+        if (def->mtubytes) {
+            g_string_append_printf(link_str, "mtu=%d\n", def->mtubytes);
+        }
+
+        if (link_str->len > 0) {
+            g_string_append_printf(s, "\n[802-3-ethernet]\n%s", link_str->str);
+        }
+
+        g_string_free(link_str, TRUE);
     }
 
     if (def->type == ND_VLAN) {
diff --git a/tests/generate.py b/tests/generate.py
index af0e0fc..f448d5c 100755
--- a/tests/generate.py
+++ b/tests/generate.py
@@ -1151,6 +1151,91 @@ method=link-local
         self.assert_networkd({'eth0.link': '[Match]\nOriginalName=eth0\n\n[Link]\nWakeOnLan=magic\n'})
         self.assert_udev(None)
 
+    def test_eth_mtu(self):
+        self.generate('''network:
+  version: 2
+  renderer: NetworkManager
+  ethernets:
+    eth1:
+      mtu: 1280
+      dhcp4: n''')
+
+        self.assert_networkd({'eth1.link': '[Match]\nOriginalName=eth1\n\n[Link]\nWakeOnLan=off\nMTUBytes=1280\n'})
+        self.assert_nm({'eth1': '''[connection]
+id=netplan-eth1
+type=ethernet
+interface-name=eth1
+
+[ethernet]
+wake-on-lan=0
+
+[802-3-ethernet]
+mtu=1280
+
+[ipv4]
+method=link-local
+'''})
+
+    def test_mtu_all(self):
+        self.generate(textwrap.dedent("""
+            network:
+              version: 2
+              renderer: NetworkManager
+              ethernets:
+                eth1:
+                  mtu: 1280
+                  dhcp4: n
+              bonds:
+                bond0:
+                  interfaces:
+                  - eth1
+                  mtu: 9000
+              vlans:
+                bond0.108:
+                  link: bond0
+                  id: 108"""))
+        self.assert_nm({
+            'bond0.108': '''[connection]
+id=netplan-bond0.108
+type=vlan
+interface-name=bond0.108
+
+[vlan]
+id=108
+parent=bond0
+
+[ipv4]
+method=link-local
+''',
+            'bond0': '''[connection]
+id=netplan-bond0
+type=bond
+interface-name=bond0
+
+[802-3-ethernet]
+mtu=9000
+
+[ipv4]
+method=link-local
+''',
+            'eth1': '''[connection]
+id=netplan-eth1
+type=ethernet
+interface-name=eth1
+slave-type=bond
+master=bond0
+
+[ethernet]
+wake-on-lan=0
+
+[802-3-ethernet]
+mtu=1280
+
+[ipv4]
+method=link-local
+''',
+        })
+
     def test_eth_set_mac(self):
         self.generate('''network:
   version: 2