Merge pull request #3265 from c-po/ethernet-mtu-T5862

ethernet: T5862: default MTU is not acceptable in some environments

9 files changed, 30 insertions, 7 deletions

diff --git a/interface-definitions/include/interface/mtu-68-16000.xml.i b/interface-definitions/include/interface/mtu-68-16000.xml.i
index cb666f470..df1b7b716 100644
--- a/interface-definitions/include/interface/mtu-68-16000.xml.i
+++ b/interface-definitions/include/interface/mtu-68-16000.xml.i
@@ -11,6 +11,5 @@
     </constraint>
     <constraintErrorMessage>MTU must be between 68 and 16000</constraintErrorMessage>
   </properties>
-  <defaultValue>1500</defaultValue>
 </leafNode>
 <!-- include end -->
diff --git a/interface-definitions/interfaces_bonding.xml.in b/interface-definitions/interfaces_bonding.xml.in
index 62ee0bdc7..92c0911db 100644
--- a/interface-definitions/interfaces_bonding.xml.in
+++ b/interface-definitions/interfaces_bonding.xml.in
@@ -261,6 +261,9 @@
             </children>
           </node>
           #include <include/interface/mtu-68-16000.xml.i>
+          <leafNode name="mtu">
+            <defaultValue>1500</defaultValue>
+          </leafNode>
           <leafNode name="primary">
             <properties>
               <help>Primary device interface</help>
diff --git a/interface-definitions/interfaces_bridge.xml.in b/interface-definitions/interfaces_bridge.xml.in
index 7fb5f121a..29dd61df5 100644
--- a/interface-definitions/interfaces_bridge.xml.in
+++ b/interface-definitions/interfaces_bridge.xml.in
@@ -41,6 +41,9 @@
           #include <include/interface/disable.xml.i>
           #include <include/interface/vrf.xml.i>
           #include <include/interface/mtu-68-16000.xml.i>
+          <leafNode name="mtu">
+            <defaultValue>1500</defaultValue>
+          </leafNode>
           <leafNode name="forwarding-delay">
             <properties>
               <help>Forwarding delay</help>
diff --git a/interface-definitions/interfaces_dummy.xml.in b/interface-definitions/interfaces_dummy.xml.in
index ef8ee78e7..36b4e41f2 100644
--- a/interface-definitions/interfaces_dummy.xml.in
+++ b/interface-definitions/interfaces_dummy.xml.in
@@ -46,6 +46,9 @@
             </children>
           </node>
           #include <include/interface/mtu-68-16000.xml.i>
+          <leafNode name="mtu">
+            <defaultValue>1500</defaultValue>
+          </leafNode>
           #include <include/interface/mirror.xml.i>
           #include <include/interface/netns.xml.i>
           #include <include/interface/redirect.xml.i>
diff --git a/interface-definitions/interfaces_vti.xml.in b/interface-definitions/interfaces_vti.xml.in
index 158d9afd0..39fb3131e 100644
--- a/interface-definitions/interfaces_vti.xml.in
+++ b/interface-definitions/interfaces_vti.xml.in
@@ -22,6 +22,9 @@
           #include <include/interface/ipv4-options.xml.i>
           #include <include/interface/ipv6-options.xml.i>
           #include <include/interface/mtu-68-16000.xml.i>
+          <leafNode name="mtu">
+            <defaultValue>1500</defaultValue>
+          </leafNode>
           #include <include/interface/mirror.xml.i>
           #include <include/interface/redirect.xml.i>
           #include <include/interface/vrf.xml.i>
diff --git a/interface-definitions/interfaces_wireguard.xml.in b/interface-definitions/interfaces_wireguard.xml.in
index fba1064ef..ce49de038 100644
--- a/interface-definitions/interfaces_wireguard.xml.in
+++ b/interface-definitions/interfaces_wireguard.xml.in
@@ -21,10 +21,10 @@
           #include <include/interface/disable.xml.i>
           #include <include/port-number.xml.i>
           #include <include/interface/mtu-68-16000.xml.i>
-          #include <include/interface/mirror.xml.i>
           <leafNode name="mtu">
             <defaultValue>1420</defaultValue>
           </leafNode>
+          #include <include/interface/mirror.xml.i>
           #include <include/interface/ipv4-options.xml.i>
           #include <include/interface/ipv6-options.xml.i>
           <leafNode name="fwmark">
diff --git a/python/vyos/configverify.py b/python/vyos/configverify.py
index 18642877a..4cb84194a 100644
--- a/python/vyos/configverify.py
+++ b/python/vyos/configverify.py
@@ -60,8 +60,8 @@ def verify_mtu_parent(config, parent):
     mtu = int(config['mtu'])
     parent_mtu = int(parent['mtu'])
     if mtu > parent_mtu:
-        raise ConfigError(f'Interface MTU ({mtu}) too high, ' \
-                          f'parent interface MTU is {parent_mtu}!')
+        raise ConfigError(f'Interface MTU "{mtu}" too high, ' \
+                          f'parent interface MTU is "{parent_mtu}"!')
 
 def verify_mtu_ipv6(config):
     """
@@ -76,7 +76,7 @@ def verify_mtu_ipv6(config):
         if int(config['mtu']) < min_mtu:
             interface = config['ifname']
             error_msg = f'IPv6 address will be configured on interface "{interface}",\n' \
-                        f'the required minimum MTU is {min_mtu}!'
+                        f'the required minimum MTU is "{min_mtu}"!'
 
             if 'address' in config:
                 for address in config['address']:
diff --git a/smoketest/scripts/cli/base_interfaces_test.py b/smoketest/scripts/cli/base_interfaces_test.py
index a106ebe61..9be2c2f1a 100644
--- a/smoketest/scripts/cli/base_interfaces_test.py
+++ b/smoketest/scripts/cli/base_interfaces_test.py
@@ -519,8 +519,7 @@ class BasicInterfaceTest:
                     base = self._base_path + [interface, 'vif', vlan]
                     self.cli_set(base + ['mtu', mtu_9000])
 
-            # check validate() - VIF MTU must not be larger the parent interface
-            # MTU size.
+            # check validate() - Interface MTU "9000" too high, parent interface MTU is "1500"!
             with self.assertRaises(ConfigSessionError):
                 self.cli_commit()
 
diff --git a/src/conf_mode/interfaces_ethernet.py b/src/conf_mode/interfaces_ethernet.py
index 41efdb03c..6da7e6a69 100755
--- a/src/conf_mode/interfaces_ethernet.py
+++ b/src/conf_mode/interfaces_ethernet.py
@@ -152,6 +152,19 @@ def get_config(config=None):
     base = ['interfaces', 'ethernet']
     ifname, ethernet = get_interface_dict(conf, base, with_pki=True)
 
+    # T5862 - default MTU is not acceptable in some environments
+    # There are cloud environments available where the maximum supported
+    # ethernet MTU is e.g. 1450 bytes, thus we clamp this to the adapters
+    # maximum MTU value or 1500 bytes - whatever is lower
+    if 'mtu' not in ethernet:
+        try:
+            ethernet['mtu'] = '1500'
+            max_mtu = EthernetIf(ifname).get_max_mtu()
+            if max_mtu < int(ethernet['mtu']):
+                ethernet['mtu'] = str(max_mtu)
+        except:
+            pass
+
     if 'is_bond_member' in ethernet:
         update_bond_options(conf, ethernet)