Assert that BVI loopback's mtu is the same as its bridge MTU

config/bridgedomain.py

@@ -137,11 +137,20 @@ def validate_bridgedomains(yaml):
 
         if 'bvi' in iface:
             bviname = iface['bvi']
-            if (None,None) == loopback.get_by_name(yaml, bviname):
-                msgs.append("bridgedomain %s BVI %s does not exist" % (ifname, bviname))
+            bvi_ifname, bvi_iface = loopback.get_by_name(yaml,iface['bvi'])
+            if not bvi_unique(yaml, bvi_ifname):
+                msgs.append("bridgedomain %s BVI %s is not unique" % (ifname, bvi_ifname))
                 result = False
-            if not bvi_unique(yaml, bviname):
-                msgs.append("bridgedomain %s BVI %s is not unique" % (ifname, bviname))
+            if not bvi_iface:
+                msgs.append("bridgedomain %s BVI %s does not exist" % (ifname, bvi_ifname))
+                result = False
+                continue
+
+            bvi_mtu = 1500
+            if 'mtu' in bvi_iface:
+                bvi_mtu = bvi_iface['mtu']
+            if bvi_mtu != bd_mtu:
+                msgs.append("bridgedomain %s BVI %s has MTU %d, while bridge has %d" % (ifname, bvi_ifname, bvi_mtu, bd_mtu))
                 result = False
 
         if 'interfaces' in iface:

example.yaml

@@ -73,6 +73,7 @@ loopbacks:
     addresses: [ 10.0.0.1/32, 2001:db8::1/128 ]
   loop1:
     lcp: "bvi1"
+    mtu: 2000
     addresses: [ 10.0.1.1/24, 2001:db8:1::1/64 ]
 
 bridgedomains:

unittest/yaml/correct-bridgedomain.yaml

@@ -43,6 +43,7 @@ interfaces:
 loopbacks:
   loop0:
     lcp: "bvi0"
+    mtu: 3000
     addresses: [ 192.0.2.1/29, 2001:db8:1::1/64 ]
 
 bridgedomains:

unittest/yaml/error-bridgedomain4.yaml

@@ -3,7 +3,8 @@ test:
   errors:
     expected:
      - "bridgedomain .* member .* has MTU (2000|3000|500), while bridge has 1500"
-    count: 3
+     - "bridgedomain .* BVI .* has MTU 9000, while bridge has 1500"
+    count: 4
 ---
 interfaces:
   GigabitEthernet1/0/0:
@@ -14,8 +15,13 @@ interfaces:
       101:
         mtu: 500
 
+loopbacks:
+  loop1:
+    mtu: 9000
+
 bridgedomains:
   bd10:
     description: "Bridge Domain 10"
     mtu: 1500
+    bvi: loop1
     interfaces: [ GigabitEthernet1/0/0, GigabitEthernet2/0/0, GigabitEthernet2/0/0.101 ]