Bug 1734165 - Test that padding in edns response doesn't effect parsing edns response r=necko-reviewers,valentin

Differential Revision: https://phabricator.services.mozilla.com/D186795

testing/xpcshell/moz-http2/moz-http2.js

@@ -347,6 +347,7 @@ function handleRequest(req, res) {
       return null;
     }
 
+    let answers = [];
     if (packet.questions.length && packet.questions[0].name.endsWith(".pd")) {
       // Bug 1543811: test edns padding extension. Return whether padding was
       // included via the first half of the ip address (1.1 vs 2.2) and the
@@ -357,6 +358,16 @@ function handleRequest(req, res) {
         packet.additionals[0].type == "OPT" &&
         packet.additionals[0].options.some(o => o.type === "PADDING")
       ) {
+        // add padding to the response, because the client must be able ignore it
+        answers.push({
+          name: ".",
+          type: "PADDING",
+          data: Buffer.from(
+            // PADDING_PADDING_PADDING
+            "50414444494e475f50414444494e475f50414444494e47",
+            "hex"
+          ),
+        });
         responseIP =
           "1.1." +
           ((requestPayload.length >> 8) & 0xff) +
@@ -397,7 +408,6 @@ function handleRequest(req, res) {
       return responseIP;
     }
 
-    let answers = [];
     if (
       responseIP != "none" &&
       responseType(packet, responseIP) == packet.questions[0].type