Undeprecate use_original_dst (#14397)

See #5355

Risk Level: Low
Testing: Listener unit tests, grep
Docs Changes: Generated documentation for the proto field

Signed-off-by: Taylor Barrella <tabarr@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 357ed13f5d6c12ac0ef15e2d05216afa53953527

envoy/config/listener/v3/listener.proto

@@ -93,9 +93,7 @@ message Listener {
     }
   }
 
-  reserved 14, 4;
-
-  reserved "use_original_dst";
+  reserved 14;
 
   // The unique name by which this listener is known. If no name is provided,
   // Envoy will allocate an internal UUID for the listener. If the listener is to be dynamically
@@ -116,6 +114,13 @@ message Listener {
   // :ref:`FAQ entry <faq_how_to_setup_sni>`.
   repeated FilterChain filter_chains = 3;
 
+  // If a connection is redirected using *iptables*, the port on which the proxy
+  // receives it might be different from the original destination address. When this flag is set to
+  // true, the listener hands off redirected connections to the listener associated with the
+  // original destination address. If there is no listener associated with the original destination
+  // address, the connection is handled by the listener that receives it. Defaults to false.
+  google.protobuf.BoolValue use_original_dst = 4;
+
   // The default filter chain if none of the filter chain matches. If no default filter chain is supplied,
   // the connection will be closed. The filter chain match is ignored in this field.
   FilterChain default_filter_chain = 25;

envoy/config/listener/v4alpha/listener.proto

@@ -96,9 +96,7 @@ message Listener {
     }
   }
 
-  reserved 14, 4;
-
-  reserved "use_original_dst";
+  reserved 14;
 
   // The unique name by which this listener is known. If no name is provided,
   // Envoy will allocate an internal UUID for the listener. If the listener is to be dynamically
@@ -119,6 +117,13 @@ message Listener {
   // :ref:`FAQ entry <faq_how_to_setup_sni>`.
   repeated FilterChain filter_chains = 3;
 
+  // If a connection is redirected using *iptables*, the port on which the proxy
+  // receives it might be different from the original destination address. When this flag is set to
+  // true, the listener hands off redirected connections to the listener associated with the
+  // original destination address. If there is no listener associated with the original destination
+  // address, the connection is handled by the listener that receives it. Defaults to false.
+  google.protobuf.BoolValue use_original_dst = 4;
+
   // The default filter chain if none of the filter chain matches. If no default filter chain is supplied,
   // the connection will be closed. The filter chain match is ignored in this field.
   FilterChain default_filter_chain = 25;