From 6ce28c43af63d0aba376318a4ece1e91eea8a683 Mon Sep 17 00:00:00 2001
From: "Joshua M. Boniface" <joshua@boniface.me>
Date: Sat, 9 Oct 2021 18:48:56 -0400
Subject: [PATCH] Add MTU value checking and log messages

Ensures that if a specified MTU is more than the maximum it is set to
the maximum instead, and adds warning messages for both situations.
---
 .../pvcnoded/objects/VXNetworkInstance.py     | 40 ++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/node-daemon/pvcnoded/objects/VXNetworkInstance.py b/node-daemon/pvcnoded/objects/VXNetworkInstance.py
index fc2752a8..52c2205e 100644
--- a/node-daemon/pvcnoded/objects/VXNetworkInstance.py
+++ b/node-daemon/pvcnoded/objects/VXNetworkInstance.py
@@ -83,9 +83,28 @@ class VXNetworkInstance(object):
         except Exception:
             self.vx_mtu = None
 
+        update_mtu = False
+
         # Explicitly set the MTU to max_mtu if unset (in Zookeeper too assuming the key exists)
         if self.vx_mtu == '' or self.vx_mtu is None:
+            self.logger.out(
+                'MTU not specified; setting to maximum MTU {} instead'.format(self.max_mtu),
+                prefix='VNI {}'.format(self.vni),
+                state='w'
+            )
             self.vx_mtu = self.max_mtu
+            update_mtu = True
+        # Ensure the MTU is valid
+        if self.vx_mtu > self.max_mtu:
+            self.logger.out(
+                'MTU {} is larger than maximum MTU {}; setting to maximum MTU instead'.format(self.vx_mtu, self.max_mtu),
+                prefix='VNI {}'.format(self.vni),
+                state='w'
+            )
+            self.vx_mtu = self.max_mtu
+            update_mtu = True
+
+        if update_mtu:
             # Try block for migration purposes
             try:
                 self.zkhandler.write([
@@ -145,11 +164,30 @@ class VXNetworkInstance(object):
         except Exception:
             self.vx_mtu = None
 
+        update_mtu = False
+
         # Explicitly set the MTU to max_mtu if unset (in Zookeeper too assuming the key exists)
         if self.vx_mtu == '' or self.vx_mtu is None:
+            self.logger.out(
+                'MTU not specified; setting to maximum MTU {} instead'.format(self.max_mtu),
+                prefix='VNI {}'.format(self.vni),
+                state='w'
+            )
             self.vx_mtu = self.max_mtu
+            update_mtu = True
+        # Ensure the MTU is valid
+        if self.vx_mtu > self.max_mtu:
+            self.logger.out(
+                'MTU {} is larger than maximum MTU {}; setting to maximum MTU instead'.format(self.vx_mtu, self.max_mtu),
+                prefix='VNI {}'.format(self.vni),
+                state='w'
+            )
+            self.vx_mtu = self.max_mtu
+            update_mtu = True
+
+        if update_mtu:
+            # Try block for migration purposes
             try:
-                # Try block for migration purposes
                 self.zkhandler.write([
                     (('network.mtu', self.vni), self.vx_mtu)
                 ])