tor-browser

test_http3_fast_fallback.js (27721B)

---

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

var { setTimeout } = ChromeUtils.importESModule(
 "resource://gre/modules/Timer.sys.mjs"
);

let h2Port;
let h3Port;
let trrServer;

const { TestUtils } = ChromeUtils.importESModule(
 "resource://testing-common/TestUtils.sys.mjs"
);
const certOverrideService = Cc[
 "@mozilla.org/security/certoverride;1"
].getService(Ci.nsICertOverrideService);

add_setup(async function setup() {
 h3Port = Services.env.get("MOZHTTP3_PORT_NO_RESPONSE");
 Assert.notEqual(h3Port, null);
 Assert.notEqual(h3Port, "");

 trrServer = new TRRServer();
 await trrServer.start();
 h2Port = trrServer.port();

 trr_test_setup();

 if (mozinfo.socketprocess_networking) {
   Services.dns; // Needed to trigger socket process.
   await TestUtils.waitForCondition(() => Services.io.socketProcessLaunched);
 }

 Services.prefs.setIntPref("network.trr.mode", 2); // TRR first
 Services.prefs.setBoolPref("network.http.http3.enable", true);
 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 6);
 Services.prefs.setBoolPref(
   "network.dns.https_rr.check_record_with_cname",
   false
 );

 registerCleanupFunction(async () => {
   trr_clear_prefs();
   Services.prefs.clearUserPref("network.dns.upgrade_with_https_rr");
   Services.prefs.clearUserPref("network.dns.use_https_rr_as_altsvc");
   Services.prefs.clearUserPref("network.dns.echconfig.enabled");
   Services.prefs.clearUserPref("network.dns.http3_echconfig.enabled");
   Services.prefs.clearUserPref(
     "network.dns.echconfig.fallback_to_origin_when_all_failed"
   );
   Services.prefs.clearUserPref("network.dns.httpssvc.reset_exclustion_list");
   Services.prefs.clearUserPref("network.http.http3.enable");
   Services.prefs.clearUserPref(
     "network.dns.httpssvc.http3_fast_fallback_timeout"
   );
   Services.prefs.clearUserPref(
     "network.http.http3.alt-svc-mapping-for-testing"
   );
   Services.prefs.clearUserPref("network.http.http3.backup_timer_delay");
   Services.prefs.clearUserPref("network.http.speculative-parallel-limit");
   Services.prefs.clearUserPref(
     "network.http.http3.parallel_fallback_conn_limit"
   );
   Services.prefs.clearUserPref(
     "network.dns.https_rr.check_record_with_cname"
   );
   if (trrServer) {
     await trrServer.stop();
   }
 });
});

function makeChan(url) {
 let chan = NetUtil.newChannel({
   uri: url,
   loadUsingSystemPrincipal: true,
   contentPolicyType: Ci.nsIContentPolicy.TYPE_DOCUMENT,
 }).QueryInterface(Ci.nsIHttpChannel);
 chan.loadFlags = Ci.nsIChannel.LOAD_INITIAL_DOCUMENT_URI;
 return chan;
}

function channelOpenPromise(chan, flags, delay) {
 // eslint-disable-next-line no-async-promise-executor
 return new Promise(async resolve => {
   function finish(req, buffer) {
     resolve([req, buffer]);
     certOverrideService.setDisableAllSecurityChecksAndLetAttackersInterceptMyData(
       false
     );
   }
   certOverrideService.setDisableAllSecurityChecksAndLetAttackersInterceptMyData(
     true
   );
   if (delay) {
     // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
     await new Promise(r => setTimeout(r, delay));
   }
   chan.asyncOpen(new ChannelListener(finish, null, flags));
 });
}

let CheckOnlyHttp2Listener = function () {};

CheckOnlyHttp2Listener.prototype = {
 onStartRequest: function testOnStartRequest() {},

 onDataAvailable: function testOnDataAvailable(request, stream, off, cnt) {
   read_stream(stream, cnt);
 },

 onStopRequest: function testOnStopRequest(request, status) {
   Assert.equal(status, Cr.NS_OK);
   let httpVersion = "";
   try {
     httpVersion = request.protocolVersion;
   } catch (e) {}
   Assert.equal(httpVersion, "h2");

   let routed = "NA";
   try {
     routed = request.getRequestHeader("Alt-Used");
   } catch (e) {}
   dump("routed is " + routed + "\n");
   Assert.ok(routed === "0" || routed === "NA");
   this.finish();
 },
};

async function fast_fallback_test() {
 let result = 1;
 // We need to loop here because we need to wait for AltSvc storage to
 // to be started.
 // We also do not have a way to verify that HTTP3 has been tried, because
 // the fallback is automatic, so try a couple of times.
 do {
   // We need to close HTTP2 connections, otherwise our connection pooling
   // will dispatch the request over already existing HTTP2 connection.
   Services.obs.notifyObservers(null, "net:prune-all-connections");
   let chan = makeChan(`https://foo.example.com:${h2Port}/`);
   let listener = new CheckOnlyHttp2Listener();
   await altsvcSetupPromise(chan, listener);
   result++;
 } while (result < 3);
}

// Test the case when speculative connection is enabled. In this case, when the
// backup connection is ready, the http transaction is still in pending
// queue because the h3 connection is never ready to accept transactions.
add_task(async function test_fast_fallback_with_speculative_connection() {
 Services.prefs.setBoolPref("network.http.http3.enable", true);
 Services.prefs.setCharPref("network.dns.localDomains", "foo.example.com");
 // Set AltSvc to point to not existing HTTP3 server on port 443
 Services.prefs.setCharPref(
   "network.http.http3.alt-svc-mapping-for-testing",
   "foo.example.com;h3=:" + h3Port
 );
 Services.prefs.setBoolPref("network.dns.disableIPv6", true);
 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 6);

 await fast_fallback_test();
});

// Test the case when speculative connection is disabled. In this case, when the
// back connection is ready, the http transaction is already activated,
// but the socket is not ready to write.
add_task(async function test_fast_fallback_without_speculative_connection() {
 // Make sure the h3 connection created by the previous test is cleared.
 Services.obs.notifyObservers(null, "net:cancel-all-connections");
 // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
 await new Promise(resolve => setTimeout(resolve, 1000));
 // Clear the h3 excluded list, otherwise the Alt-Svc mapping will not be used.
 Services.obs.notifyObservers(null, "network:reset-http3-excluded-list");
 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 0);

 await fast_fallback_test();

 Services.prefs.clearUserPref(
   "network.http.http3.alt-svc-mapping-for-testing"
 );
});

// Test when echConfig is disabled and we have https rr for http3. We use a
// longer timeout in this test, so when fast fallback timer is triggered, the
// http transaction is already activated.
add_task(async function testFastfallback() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", false);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   1000
 );

 await trrServer.registerDoHAnswers("test.fastfallback.com", "HTTPS", {
   answers: [
     {
       name: "test.fastfallback.com",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.fastfallback1.com",
         values: [
           { key: "alpn", value: "h3" },
           { key: "no-default-alpn" },
           { key: "port", value: h3Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
     {
       name: "test.fastfallback.com",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 2,
         name: "test.fastfallback2.com",
         values: [
           { key: "alpn", value: "h2" },
           { key: "port", value: h2Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.fastfallback1.com", "A", {
   answers: [
     {
       name: "test.fastfallback1.com",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.fastfallback2.com", "A", {
   answers: [
     {
       name: "test.fastfallback2.com",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.fastfallback.com/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});

// Like the previous test, but with a shorter timeout, so when fast fallback
// timer is triggered, the http transaction is still in pending queue.
add_task(async function testFastfallback1() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", false);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   10
 );

 await trrServer.registerDoHAnswers("test.fastfallback.org", "HTTPS", {
   answers: [
     {
       name: "test.fastfallback.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.fastfallback1.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "no-default-alpn" },
           { key: "port", value: h3Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
     {
       name: "test.fastfallback.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 2,
         name: "test.fastfallback2.org",
         values: [
           { key: "alpn", value: "h2" },
           { key: "port", value: h2Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.fastfallback1.org", "A", {
   answers: [
     {
       name: "test.fastfallback1.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.fastfallback2.org", "A", {
   answers: [
     {
       name: "test.fastfallback2.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.fastfallback.org/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});

// Test when echConfig is enabled, we can sucessfully fallback to the last
// record.
add_task(async function testFastfallbackWithEchConfig() {
 // XXX(valenting): This test takes 30s to fallback.
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", true);
 Services.prefs.setBoolPref("network.dns.http3_echconfig.enabled", true);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   50
 );

 await trrServer.registerDoHAnswers("test.ech.org", "HTTPS", {
   answers: [
     {
       name: "test.ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.ech1.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "port", value: h3Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
     {
       name: "test.ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 2,
         name: "test.ech2.org",
         values: [
           { key: "alpn", value: "h2" },
           { key: "port", value: h2Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
     {
       name: "test.ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 3,
         name: "test.ech3.org",
         values: [
           { key: "alpn", value: "h2" },
           { key: "port", value: h2Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.ech1.org", "A", {
   answers: [
     {
       name: "test.ech1.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.ech3.org", "A", {
   answers: [
     {
       name: "test.ech3.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.ech.org/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});

// Test when echConfig is enabled, the connection should fail when not all
// records have echConfig.
add_task(async function testFastfallbackWithpartialEchConfig() {
 // XXX(valenting): This test takes 30s to fallback.
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", true);
 Services.prefs.setBoolPref("network.dns.http3_echconfig.enabled", true);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   50
 );

 await trrServer.registerDoHAnswers("test.partial_ech.org", "HTTPS", {
   answers: [
     {
       name: "test.partial_ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.partial_ech1.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "port", value: h3Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
     {
       name: "test.partial_ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 2,
         name: "test.partial_ech2.org",
         values: [
           { key: "alpn", value: "h2" },
           { key: "port", value: h2Port },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.partial_ech1.org", "A", {
   answers: [
     {
       name: "test.partial_ech1.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.partial_ech2.org", "A", {
   answers: [
     {
       name: "test.partial_ech2.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.partial_ech.org/server-timing`);
 await channelOpenPromise(chan, CL_EXPECT_LATE_FAILURE | CL_ALLOW_UNKNOWN_CL);
});

add_task(async function testFastfallbackWithoutEchConfig() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   50
 );

 await trrServer.registerDoHAnswers("test.no_ech_h2.org", "HTTPS", {
   answers: [
     {
       name: "test.no_ech_h2.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.no_ech_h3.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "port", value: h3Port },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.no_ech_h3.org", "A", {
   answers: [
     {
       name: "test.no_ech_h3.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.no_ech_h2.org", "A", {
   answers: [
     {
       name: "test.no_ech_h2.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.no_ech_h2.org:${h2Port}/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});

add_task(async function testH3FallbackWithMultipleTransactions() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", false);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 // Disable fast fallback.
 Services.prefs.setIntPref(
   "network.http.http3.parallel_fallback_conn_limit",
   0
 );
 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 0);

 await trrServer.registerDoHAnswers("test.multiple_trans.org", "HTTPS", {
   answers: [
     {
       name: "test.multiple_trans.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.multiple_trans.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "port", value: h3Port },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.multiple_trans.org", "A", {
   answers: [
     {
       name: "test.multiple_trans.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let promises = [];
 for (let i = 0; i < 2; ++i) {
   let chan = makeChan(
     `https://test.multiple_trans.org:${h2Port}/server-timing`
   );
   promises.push(channelOpenPromise(chan));
 }

 let res = await Promise.all(promises);
 res.forEach(function (e) {
   let [req] = e;
   Assert.equal(req.protocolVersion, "h2");
   let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
   Assert.equal(internal.remotePort, h2Port);
 });
});

add_task(async function testTwoFastFallbackTimers() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", false);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 6);
 Services.prefs.clearUserPref(
   "network.http.http3.parallel_fallback_conn_limit"
 );

 Services.prefs.setCharPref(
   "network.http.http3.alt-svc-mapping-for-testing",
   "foo.fallback.org;h3=:" + h3Port
 );

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   10
 );
 Services.prefs.setIntPref("network.http.http3.backup_timer_delay", 100);

 await trrServer.registerDoHAnswers("foo.fallback.org", "HTTPS", {
   answers: [
     {
       name: "foo.fallback.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "foo.fallback.org",
         values: [
           { key: "alpn", value: "h3" },
           { key: "port", value: h3Port },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("foo.fallback.org", "A", {
   answers: [
     {
       name: "foo.fallback.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 // Test the case that http3 backup timer is triggered after
 // fast fallback timer or HTTPS RR.
 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   10
 );
 Services.prefs.setIntPref("network.http.http3.backup_timer_delay", 100);

 async function createChannelAndStartTest() {
   let chan = makeChan(`https://foo.fallback.org:${h2Port}/server-timing`);
   let [req] = await channelOpenPromise(chan);
   Assert.equal(req.protocolVersion, "h2");
   let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
   Assert.equal(internal.remotePort, h2Port);
 }

 await createChannelAndStartTest();

 Services.obs.notifyObservers(null, "net:prune-all-connections");
 Services.obs.notifyObservers(null, "network:reset-http3-excluded-list");
 Services.dns.clearCache(true);

 // Do the same test again, but with a different configuration.
 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   100
 );
 Services.prefs.setIntPref("network.http.http3.backup_timer_delay", 10);

 await createChannelAndStartTest();
});

add_task(async function testH3FastFallbackWithMultipleTransactions() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", false);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref("network.http.speculative-parallel-limit", 6);
 Services.prefs.clearUserPref(
   "network.http.http3.parallel_fallback_conn_limit"
 );

 Services.prefs.setIntPref("network.http.http3.backup_timer_delay", 500);

 Services.prefs.setCharPref(
   "network.http.http3.alt-svc-mapping-for-testing",
   "test.multiple_fallback_trans.org;h3=:" + h3Port
 );

 await trrServer.registerDoHAnswers("test.multiple_fallback_trans.org", "A", {
   answers: [
     {
       name: "test.multiple_fallback_trans.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let promises = [];
 for (let i = 0; i < 3; ++i) {
   let chan = makeChan(
     `https://test.multiple_fallback_trans.org:${h2Port}/server-timing`
   );
   if (i == 0) {
     promises.push(channelOpenPromise(chan));
   } else {
     promises.push(channelOpenPromise(chan, null, 500));
   }
 }

 let res = await Promise.all(promises);
 res.forEach(function (e) {
   let [req] = e;
   Assert.equal(req.protocolVersion, "h2");
   let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
   Assert.equal(internal.remotePort, h2Port);
 });
});

add_task(async function testFastfallbackToTheSameRecord() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", true);
 Services.prefs.setBoolPref("network.dns.http3_echconfig.enabled", true);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   1000
 );

 await trrServer.registerDoHAnswers("test.ech.org", "HTTPS", {
   answers: [
     {
       name: "test.ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.ech1.org",
         values: [
           { key: "alpn", value: ["h3", "h2"] },
           { key: "port", value: h2Port },
           { key: "echconfig", value: "456..." },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.ech1.org", "A", {
   answers: [
     {
       name: "test.ech1.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.ech.org/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});

// Similar to the previous test, but no ech.
add_task(async function testFastfallbackToTheSameRecord1() {
 Services.prefs.setBoolPref("network.dns.upgrade_with_https_rr", true);
 Services.prefs.setBoolPref("network.dns.use_https_rr_as_altsvc", true);
 Services.prefs.setBoolPref("network.dns.echconfig.enabled", true);
 Services.prefs.setBoolPref("network.dns.http3_echconfig.enabled", true);

 Services.prefs.setIntPref("network.trr.mode", 3);
 Services.prefs.setCharPref(
   "network.trr.uri",
   `https://foo.example.com:${trrServer.port()}/dns-query`
 );
 Services.prefs.setBoolPref("network.http.http3.enable", true);

 Services.prefs.setIntPref(
   "network.dns.httpssvc.http3_fast_fallback_timeout",
   1000
 );

 await trrServer.registerDoHAnswers("test.no_ech.org", "HTTPS", {
   answers: [
     {
       name: "test.no_ech.org",
       ttl: 55,
       type: "HTTPS",
       flush: false,
       data: {
         priority: 1,
         name: "test.no_ech.org",
         values: [
           { key: "alpn", value: ["h3", "h2"] },
           { key: "port", value: h2Port },
         ],
       },
     },
   ],
 });

 await trrServer.registerDoHAnswers("test.no_ech.org", "A", {
   answers: [
     {
       name: "test.no_ech.org",
       ttl: 55,
       type: "A",
       flush: false,
       data: "127.0.0.1",
     },
   ],
 });

 let chan = makeChan(`https://test.no_ech.org/server-timing`);
 let [req] = await channelOpenPromise(chan);
 Assert.equal(req.protocolVersion, "h2");
 let internal = req.QueryInterface(Ci.nsIHttpChannelInternal);
 Assert.equal(internal.remotePort, h2Port);
});