feat: start merging filtering into testingx (ooni#1234)

## Checklist

- [x] I have read the [contribution
guidelines](https://github.com/ooni/probe-cli/blob/master/CONTRIBUTING.md)
- [x] reference issue for this pull request:
ooni/probe#1803
- [x] if you changed anything related to how experiments work and you
need to reflect these changes in the ooni/spec repository, please link
to the related ooni/spec pull request: N/A
- [x] if you changed code inside an experiment, make sure you bump its
version number: N/A

## Description

To continue rewriting Jafar based tests to use netemx, the next step is
to adapt the proxies used by Jafar to be usable from within netemx to
implement equivalent test cases.

In turn, netemx is using testingx for general-purpose test servers that
could also be interesting for other packages.

We also have the netxlite/filtering package, which is ~fine but has a
string-based API, where an interface-based API would be more proper and
easier to compose. (We historically use a string-based API there because
we previously attempted to replace Jafar with code in userspace usinf
netxlite/filtering.)

The first step in this quest is therefore to rewrite the DNS code inside
netxlite/filtering and move it to testingx.

While there rename netemx.UDPResolverFactory to DNSOverUDPServerFactory
for consistency.

internal/experiment/dnsping/dnsping_test.go

@@ -99,7 +99,7 @@ func TestMeasurer_run(t *testing.T) {
 
  t.Run("with netem: without DPI: expect success", func(t *testing.T) {
  // create a new test environment
- env := netemx.MustNewQAEnv(netemx.QAEnvOptionNetStack("8.8.8.8", &netemx.UDPResolverFactory{}))
+ env := netemx.MustNewQAEnv(netemx.QAEnvOptionNetStack("8.8.8.8", &netemx.DNSOverUDPServerFactory{}))
  defer env.Close()
 
  // we use the same configuration for all resolvers
@@ -146,7 +146,7 @@ func TestMeasurer_run(t *testing.T) {
 
  t.Run("with netem: with DNS spoofing: expect to see delayed responses", func(t *testing.T) {
  // create a new test environment
- env := netemx.MustNewQAEnv(netemx.QAEnvOptionNetStack("8.8.8.8", &netemx.UDPResolverFactory{}))
+ env := netemx.MustNewQAEnv(netemx.QAEnvOptionNetStack("8.8.8.8", &netemx.DNSOverUDPServerFactory{}))
  defer env.Close()
 
  // we use the same configuration for all resolvers

internal/netemx/dnsoverhttps.go

@@ -14,5 +14,7 @@ var _ HTTPHandlerFactory = &DNSOverHTTPSHandlerFactory{}
 
 // NewHandler implements QAEnvHTTPHandlerFactory.
 func (f *DNSOverHTTPSHandlerFactory) NewHandler(env NetStackServerFactoryEnv, stack *netem.UNetStack) http.Handler {
- return &testingx.DNSOverHTTPSHandler{Config: env.OtherResolversConfig()}
+ return &testingx.DNSOverHTTPSHandler{
+ RoundTripper: testingx.NewDNSRoundTripperWithDNSConfig(env.OtherResolversConfig()),
+ }
 }

internal/netemx/udpresolver.go → internal/netemx/dnsoverudp.go

@@ -11,37 +11,37 @@ import (
  "github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
-// UDPResolverFactory implements [NetStackServerFactory] for DNS-over-UDP servers.
+// DNSOverUDPServerFactory implements [NetStackServerFactory] for DNS-over-UDP servers.
 //
 // When this factory constructs a [NetStackServer], it will use:
 //
 // 1. the [NetStackServerFactoryEnv.OtherResolversConfig] as DNS configuration;
 //
-// 2. the [NetStackServerFactoryEnv.Logger] as the logger.
+// 2. the [NetStackServerFactoryEnv.Logger] as logger.
 //
 // Use this factory along with [QAEnvOptionNetStack] to create DNS-over-UDP servers.
-type UDPResolverFactory struct{}
+type DNSOverUDPServerFactory struct{}
 
-var _ NetStackServerFactory = &UDPResolverFactory{}
+var _ NetStackServerFactory = &DNSOverUDPServerFactory{}
 
 // MustNewServer implements NetStackServerFactory.
-func (f *UDPResolverFactory) MustNewServer(env NetStackServerFactoryEnv, stack *netem.UNetStack) NetStackServer {
- return udpResolverMustNewServer(env.OtherResolversConfig(), env.Logger(), stack)
+func (f *DNSOverUDPServerFactory) MustNewServer(env NetStackServerFactoryEnv, stack *netem.UNetStack) NetStackServer {
+ return dnsOverUDPResolverMustNewServer(env.OtherResolversConfig(), env.Logger(), stack)
 }
 
-type udpResolverFactoryForGetaddrinfo struct{}
+type dnsOverUDPServerFactoryForGetaddrinfo struct{}
 
-var _ NetStackServerFactory = &udpResolverFactoryForGetaddrinfo{}
+var _ NetStackServerFactory = &dnsOverUDPServerFactoryForGetaddrinfo{}
 
 // MustNewServer implements NetStackServerFactory.
-func (f *udpResolverFactoryForGetaddrinfo) MustNewServer(env NetStackServerFactoryEnv, stack *netem.UNetStack) NetStackServer {
- return udpResolverMustNewServer(env.ISPResolverConfig(), env.Logger(), stack)
+func (f *dnsOverUDPServerFactoryForGetaddrinfo) MustNewServer(env NetStackServerFactoryEnv, stack *netem.UNetStack) NetStackServer {
+ return dnsOverUDPResolverMustNewServer(env.ISPResolverConfig(), env.Logger(), stack)
 }
 
-// udpResolverMustNewServer is an internal factory for creating a [NetStackServer] that
+// dnsOverUDPResolverMustNewServer is an internal factory for creating a [NetStackServer] that
 // runs a DNS-over-UDP server using the configured logger, DNS config, and stack.
-func udpResolverMustNewServer(config *netem.DNSConfig, logger model.Logger, stack *netem.UNetStack) NetStackServer {
- return &udpResolver{
+func dnsOverUDPResolverMustNewServer(config *netem.DNSConfig, logger model.Logger, stack *netem.UNetStack) NetStackServer {
+ return &dnsOverUDPResolver{
  closers: []io.Closer{},
  config: config,
  logger: logger,
@@ -50,7 +50,7 @@ func udpResolverMustNewServer(config *netem.DNSConfig, logger model.Logger, stac
  }
 }
 
-type udpResolver struct {
+type dnsOverUDPResolver struct {
  closers []io.Closer
  config *netem.DNSConfig
  logger model.Logger
@@ -59,7 +59,7 @@ type udpResolver struct {
 }
 
 // Close implements NetStackServer.
-func (srv *udpResolver) Close() error {
+func (srv *dnsOverUDPResolver) Close() error {
  // make the method locked as requested by the documentation
  defer srv.mu.Unlock()
  srv.mu.Lock()
@@ -75,7 +75,7 @@ func (srv *udpResolver) Close() error {
 }
 
 // MustStart implements NetStackServer.
-func (srv *udpResolver) MustStart() {
+func (srv *dnsOverUDPResolver) MustStart() {
  // make the method locked as requested by the documentation
  defer srv.mu.Unlock()
  srv.mu.Lock()

internal/netemx/udpresolver_test.go → internal/netemx/dnsoverudp_test.go

@@ -10,9 +10,9 @@ import (
  "github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
-func TestUDPResolverFactory(t *testing.T) {
+func TestDNSOverUDPServerFactory(t *testing.T) {
  env := MustNewQAEnv(
- QAEnvOptionNetStack(AddressDNSGoogle8844, &UDPResolverFactory{}),
+ QAEnvOptionNetStack(AddressDNSGoogle8844, &DNSOverUDPServerFactory{}),
  )
  defer env.Close()
 

internal/netemx/example_test.go

@@ -20,8 +20,8 @@ import (
 // to use this QA environment in all the examples for this package.
 func exampleNewEnvironment() *netemx.QAEnv {
  return netemx.MustNewQAEnv(
- netemx.QAEnvOptionNetStack("8.8.4.4", &netemx.UDPResolverFactory{}),
- netemx.QAEnvOptionNetStack("9.9.9.9", &netemx.UDPResolverFactory{}),
+ netemx.QAEnvOptionNetStack("8.8.4.4", &netemx.DNSOverUDPServerFactory{}),
+ netemx.QAEnvOptionNetStack("9.9.9.9", &netemx.DNSOverUDPServerFactory{}),
  netemx.QAEnvOptionClientAddress(netemx.DefaultClientAddress),
  netemx.QAEnvOptionHTTPServer(
  netemx.AddressWwwExampleCom, netemx.ExampleWebPageHandlerFactory()),

internal/netemx/qaenv.go

@@ -182,10 +182,10 @@ func MustNewQAEnv(options ...QAEnvOption) *QAEnv {
  }
 
  // make sure we're going to create the ISP's DNS resolver.
- qaEnvOptionNetStack(config.ispResolver, &udpResolverFactoryForGetaddrinfo{})(config)
+ qaEnvOptionNetStack(config.ispResolver, &dnsOverUDPServerFactoryForGetaddrinfo{})(config)
 
  // make sure we're going to create the root DNS resolver.
- qaEnvOptionNetStack(config.rootResolver, &UDPResolverFactory{})(config)
+ qaEnvOptionNetStack(config.rootResolver, &DNSOverUDPServerFactory{})(config)
 
  // use a prefix logger for the QA env
  prefixLogger := &logx.PrefixLogger{

internal/netemx/scenario.go

@@ -125,7 +125,7 @@ func MustNewScenario(config []*ScenarioDomainAddresses) *QAEnv {
  for _, addr := range sad.Addresses {
  opts = append(opts, QAEnvOptionNetStack(
  addr,
- &UDPResolverFactory{},
+ &DNSOverUDPServerFactory{},
  &HTTPSecureServerFactory{
  Factory: &DNSOverHTTPSHandlerFactory{},
  Ports: []int{443},

internal/netxlite/dnsoverudp_test.go

@@ -12,9 +12,9 @@ import (
  "github.com/apex/log"
  "github.com/google/go-cmp/cmp"
  "github.com/miekg/dns"
+ "github.com/ooni/netem"
  "github.com/ooni/probe-cli/v3/internal/mocks"
  "github.com/ooni/probe-cli/v3/internal/model"
- "github.com/ooni/probe-cli/v3/internal/netxlite/filtering"
  "github.com/ooni/probe-cli/v3/internal/testingx"
 )
 
@@ -252,18 +252,14 @@ func TestDNSOverUDPTransport(t *testing.T) {
  })
 
  t.Run("using a real server", func(t *testing.T) {
- srvr := &filtering.DNSServer{
- OnQuery: func(domain string) filtering.DNSAction {
- return filtering.DNSActionCache
- },
- Cache: map[string][]string{
- "dns.google.": {"8.8.8.8"},
- },
- }
- listener, err := srvr.Start("127.0.0.1:0")
- if err != nil {
- t.Fatal(err)
- }
+ udpAddr := &net.UDPAddr{
+ IP: net.IPv4(127, 0, 0, 1),
+ Port: 0,
+ }
+ dnsConfig := netem.NewDNSConfig()
+ dnsConfig.AddRecord("dns.google", "", "8.8.8.8")
+ dnsRtx := testingx.NewDNSRoundTripperWithDNSConfig(dnsConfig)
+ listener := testingx.MustNewDNSOverUDPListener(udpAddr, &testingx.DNSOverUDPStdlibListener{}, dnsRtx)
  defer listener.Close()
  dialer := NewDialerWithoutResolver(model.DiscardLogger)
  txp := NewUnwrappedDNSOverUDPTransport(dialer, listener.LocalAddr().String())
@@ -284,20 +280,20 @@ func TestDNSOverUDPTransport(t *testing.T) {
  })
 
  t.Run("recording delayed DNS responses", func(t *testing.T) {
+ dnsConfigGood := netem.NewDNSConfig()
+ dnsConfigGood.AddRecord("dns.google", "", "8.8.8.8")
+
+ dnsConfigBogus := netem.NewDNSConfig()
+ dnsConfigBogus.AddRecord("dns.google", "", "127.0.0.1")
+
  t.Run("without any context-injected traces", func(t *testing.T) {
- srvr := &filtering.DNSServer{
- OnQuery: func(domain string) filtering.DNSAction {
- return filtering.DNSActionLocalHostPlusCache
- },
- Cache: map[string][]string{
- "dns.google.": {"8.8.8.8"},
- },
- }
- listener, err := srvr.Start("127.0.0.1:0")
- if err != nil {
- t.Fatal(err)
+ udpAddr := &net.UDPAddr{
+ IP: net.IPv4(127, 0, 0, 1),
+ Port: 0,
  }
- defer listener.Close()
+ listener := testingx.MustNewDNSSimulateGWFListener(
+ udpAddr, &testingx.DNSOverUDPStdlibListener{}, dnsConfigBogus,
+ dnsConfigGood, testingx.DNSNumBogusResponses(1))
  dialer := NewDialerWithoutResolver(model.DiscardLogger)
  expectedAddress := listener.LocalAddr().String()
  txp := NewUnwrappedDNSOverUDPTransport(dialer, expectedAddress)
@@ -325,18 +321,13 @@ func TestDNSOverUDPTransport(t *testing.T) {
  goodLookupAddrs bool
  goodError bool
  )
- srvr := &filtering.DNSServer{
- OnQuery: func(domain string) filtering.DNSAction {
- return filtering.DNSActionLocalHostPlusCache
- },
- Cache: map[string][]string{
- "dns.google.": {"8.8.8.8"},
- },
- }
- listener, err := srvr.Start("127.0.0.1:0")
- if err != nil {
- t.Fatal(err)
+ udpAddr := &net.UDPAddr{
+ IP: net.IPv4(127, 0, 0, 1),
+ Port: 0,
  }
+ listener := testingx.MustNewDNSSimulateGWFListener(
+ udpAddr, &testingx.DNSOverUDPStdlibListener{}, dnsConfigBogus,
+ dnsConfigGood, testingx.DNSNumBogusResponses(1))
  defer listener.Close()
  dialer := NewDialerWithoutResolver(model.DiscardLogger)
  expectedAddress := listener.LocalAddr().String()
@@ -420,19 +411,14 @@ func TestDNSOverUDPTransport(t *testing.T) {
  goodLookupAddrs bool
  goodError bool
  )
- srvr := &filtering.DNSServer{
- OnQuery: func(domain string) filtering.DNSAction {
- return filtering.DNSActionLocalHostPlusCache
- },
- Cache: map[string][]string{
- // Note: the cache here is nonexistent so we should
- // get a "no such host" error from the server.
- },
- }
- listener, err := srvr.Start("127.0.0.1:0")
- if err != nil {
- t.Fatal(err)
- }
+ udpAddr := &net.UDPAddr{
+ IP: net.IPv4(127, 0, 0, 1),
+ Port: 0,
+ }
+ // Note: the config here is empty so we should get a "no such host" error from the server.
+ listener := testingx.MustNewDNSSimulateGWFListener(
+ udpAddr, &testingx.DNSOverUDPStdlibListener{}, dnsConfigBogus,
+ netem.NewDNSConfig(), testingx.DNSNumBogusResponses(1))
  defer listener.Close()
  dialer := NewDialerWithoutResolver(model.DiscardLogger)
  expectedAddress := listener.LocalAddr().String()