vpp: T8355: Set MTU for vpp interfaces

4 files changed, 51 insertions, 0 deletions

diff --git a/src/conf_mode/vpp_interfaces_bonding.py b/src/conf_mode/vpp_interfaces_bonding.py
index 8d9930a20..80356ce2b 100644
--- a/src/conf_mode/vpp_interfaces_bonding.py
+++ b/src/conf_mode/vpp_interfaces_bonding.py
@@ -19,10 +19,12 @@
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdep import set_dependents, call_dependents
+from vyos.configverify import verify_mtu_ipv6
 from vyos import ConfigError
 from vyos.utils.assertion import assert_mac
 from vyos.utils.process import is_systemd_service_active
 
+from vyos.ifconfig import Interface
 from vyos.ifconfig.vpp import VPPBondInterface
 from vyos.vpp.config_deps import deps_bond_dict
 from vyos.vpp.config_deps import deps_bridge_dict
@@ -174,6 +176,19 @@ def verify(config):
                 f'it already belongs to bridge interface: {", ".join(bridge_members)}.'
             )
 
+        if mtu := config.get('mtu'):
+            mtu = int(mtu)
+            max_mtu = Interface(iface).get_max_mtu()
+            min_mtu = Interface(iface).get_min_mtu()
+            if mtu > max_mtu:
+                raise ConfigError(
+                    f'Configured MTU is greater than member interface "{iface}" maximum of {max_mtu}!'
+                )
+            if mtu < min_mtu:
+                raise ConfigError(
+                    f'Configured MTU is less than member interface "{iface}" minimum of {min_mtu}!'
+                )
+
     if 'mac' in config:
         mac = config['mac']
         try:
@@ -190,6 +205,8 @@ def verify(config):
                 f'Cannot remove interface {vif_iface}: it is still in use by the PPPoE server'
             )
 
+    verify_mtu_ipv6(config)
+
 
 def generate(config):
     pass
diff --git a/src/conf_mode/vpp_interfaces_gre.py b/src/conf_mode/vpp_interfaces_gre.py
index 1258f906c..3756449a2 100644
--- a/src/conf_mode/vpp_interfaces_gre.py
+++ b/src/conf_mode/vpp_interfaces_gre.py
@@ -21,6 +21,7 @@ from vyos import ConfigError
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdep import set_dependents, call_dependents
+from vyos.configverify import verify_mtu_ipv6
 from vyos.utils.process import is_systemd_service_active
 
 from vyos.ifconfig.vpp import VPPGREInterface
@@ -128,6 +129,8 @@ def verify(config):
     if config.get('source_address') == config.get('remote'):
         raise ConfigError('Remote address must not be the same as source address')
 
+    verify_mtu_ipv6(config)
+
     # Disable checks as point-to-multipoint mode does not work without 'teib' feature that is not implemented yet
     # # check multipoint mode
     # if config.get('mode') == 'point-to-multipoint':
diff --git a/src/conf_mode/vpp_interfaces_ipip.py b/src/conf_mode/vpp_interfaces_ipip.py
index d029f3619..dd4a19e36 100644
--- a/src/conf_mode/vpp_interfaces_ipip.py
+++ b/src/conf_mode/vpp_interfaces_ipip.py
@@ -21,6 +21,7 @@ from vyos import ConfigError
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdep import set_dependents, call_dependents
+from vyos.configverify import verify_mtu_ipv6
 from vyos.utils.process import is_systemd_service_active
 
 from vyos.ifconfig.vpp import VPPIPIPInterface
@@ -102,6 +103,8 @@ def verify(config):
     if config.get('source_address') == config.get('remote'):
         raise ConfigError('Remote address must not be the same as source address')
 
+    verify_mtu_ipv6(config)
+
 
 def generate(config):
     pass
diff --git a/src/conf_mode/vpp_interfaces_vxlan.py b/src/conf_mode/vpp_interfaces_vxlan.py
index 38349cb4c..ac9a9517b 100644
--- a/src/conf_mode/vpp_interfaces_vxlan.py
+++ b/src/conf_mode/vpp_interfaces_vxlan.py
@@ -18,9 +18,14 @@
 
 from vyos import ConfigError
 
+from vyos.base import Warning
 from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdep import set_dependents, call_dependents
+from vyos.configverify import verify_mtu_ipv6
+from vyos.ifconfig import Interface
+from vyos.template import is_ipv6
+from vyos.utils.network import get_interfaces_by_ip
 from vyos.utils.process import is_systemd_service_active
 
 from vyos.ifconfig.vpp import VPPVXLANInterface
@@ -117,6 +122,29 @@ def verify(config):
     if config.get('source_address') == config.get('remote'):
         raise ConfigError('Remote address must not be the same as source address')
 
+    # VXLAN adds at least an overhead of 50 bytes - we need to check the
+    # underlying device if our VXLAN package is not going to be fragmented!
+    source_address = config['source_address']
+    vxlan_overhead = 50
+    if is_ipv6(source_address):
+        # IPv6 adds an extra 20 bytes overhead because the IPv6 header is 20
+        # bytes larger than the IPv4 header - assuming no extra options are
+        # in use.
+        vxlan_overhead += 20
+
+    ifaces_with_ip = get_interfaces_by_ip(source_address)
+    vpp_ifaces = config['vpp_ether_vif_ifaces']
+    matching_iface = next((iface for iface in ifaces_with_ip if iface in vpp_ifaces))
+
+    lower_mtu = Interface(matching_iface).get_mtu()
+    if lower_mtu < (int(config['mtu']) + vxlan_overhead):
+        Warning(
+            f'Underlying device MTU is too small ({lower_mtu} bytes) '
+            f'for VXLAN overhead ({vxlan_overhead} bytes!)'
+        )
+
+    verify_mtu_ipv6(config)
+
 
 def generate(config):
     pass