api: Document default CidrRange prefix_len (#15617)

Fixes #15579

Risk Level: n/a (no functional change)
Testing: Unit test to verify case added to docs
Docs Changes: Added definition of default value

Signed-off-by: Eric Anderson <ejona@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 54fc5dc459c06d15494fd759ac3e4c4785f6a7b5

envoy/api/v2/core/address.proto

@@ -129,6 +129,6 @@ message CidrRange {
   // IPv4 or IPv6 address, e.g. ``192.0.0.0`` or ``2001:db8::``.
   string address_prefix = 1 [(validate.rules).string = {min_bytes: 1}];
 
-  // Length of prefix, e.g. 0, 32.
+  // Length of prefix, e.g. 0, 32. Defaults to 0 when unset.
   google.protobuf.UInt32Value prefix_len = 2 [(validate.rules).uint32 = {lte: 128}];
 }

envoy/config/core/v3/address.proto

@@ -155,6 +155,6 @@ message CidrRange {
   // IPv4 or IPv6 address, e.g. ``192.0.0.0`` or ``2001:db8::``.
   string address_prefix = 1 [(validate.rules).string = {min_len: 1}];
 
-  // Length of prefix, e.g. 0, 32.
+  // Length of prefix, e.g. 0, 32. Defaults to 0 when unset.
   google.protobuf.UInt32Value prefix_len = 2 [(validate.rules).uint32 = {lte: 128}];
 }

envoy/config/core/v4alpha/address.proto

@@ -158,6 +158,6 @@ message CidrRange {
   // IPv4 or IPv6 address, e.g. ``192.0.0.0`` or ``2001:db8::``.
   string address_prefix = 1 [(validate.rules).string = {min_len: 1}];
 
-  // Length of prefix, e.g. 0, 32.
+  // Length of prefix, e.g. 0, 32. Defaults to 0 when unset.
   google.protobuf.UInt32Value prefix_len = 2 [(validate.rules).uint32 = {lte: 128}];
 }