cleanup: remove unnecessary legacy interfaces (#656)

This diff addresses another point of https://github.com/ooni/probe/issues/1956:

> - [ ] observe that we're still using a bunch of private interfaces for common interfaces such as the `Dialer`, so we can get rid of these private interfaces and always use the ones in `model`, which allows us to remove a bunch of legacy wrappers

Additional cleanups may still be possible. The more I cleanup, the more I see
there's extra legacy code we can dispose of (which seems good?).

internal/cmd/oohelperd/internal/webconnectivity/dns.go

@@ -5,8 +5,8 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/archival"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
@@ -21,7 +21,7 @@ type CtrlDNSResult = webconnectivity.ControlDNSResult
 type DNSConfig struct {
 	Domain   string
 	Out      chan CtrlDNSResult
-	Resolver netx.Resolver
+	Resolver model.Resolver
 	Wg       *sync.WaitGroup
 }
 

internal/cmd/oohelperd/internal/webconnectivity/fake_test.go

@@ -2,13 +2,14 @@ package webconnectivity
 
 import (
 	"context"
+	"errors"
 	"io"
 	"net"
 	"net/http"
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
@@ -49,7 +50,13 @@ func (c FakeResolver) Address() string {
 	return ""
 }
 
-var _ netx.Resolver = FakeResolver{}
+func (c FakeResolver) CloseIdleConnections() {}
+
+func (c FakeResolver) LookupHTTPS(ctx context.Context, domain string) (*model.HTTPSSvc, error) {
+	return nil, errors.New("not implemented")
+}
+
+var _ model.Resolver = FakeResolver{}
 
 type FakeTransport struct {
 	Err  error
@@ -75,7 +82,7 @@ func (txp FakeTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 
 func (txp FakeTransport) CloseIdleConnections() {}
 
-var _ netx.HTTPRoundTripper = FakeTransport{}
+var _ model.HTTPTransport = FakeTransport{}
 
 type FakeBody struct {
 	Data []byte

internal/cmd/oohelperd/internal/webconnectivity/measure.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 type (
@@ -22,9 +22,9 @@ type (
 // MeasureConfig contains configuration for Measure.
 type MeasureConfig struct {
 	Client            *http.Client
-	Dialer            netx.Dialer
+	Dialer            model.Dialer
 	MaxAcceptableBody int64
-	Resolver          netx.Resolver
+	Resolver          model.Resolver
 }
 
 // Measure performs the measurement described by the request and

internal/cmd/oohelperd/internal/webconnectivity/tcpconnect.go

@@ -5,7 +5,7 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
@@ -20,7 +20,7 @@ type TCPResultPair struct {
 
 // TCPConfig configures the TCP connect check.
 type TCPConfig struct {
-	Dialer   netx.Dialer
+	Dialer   model.Dialer
 	Endpoint string
 	Out      chan TCPResultPair
 	Wg       *sync.WaitGroup

internal/cmd/oohelperd/internal/webconnectivity/webconnectivity.go

@@ -6,7 +6,7 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	"github.com/ooni/probe-cli/v3/internal/version"
@@ -15,9 +15,9 @@ import (
 // Handler implements the Web Connectivity test helper HTTP API.
 type Handler struct {
 	Client            *http.Client
-	Dialer            netx.Dialer
+	Dialer            model.Dialer
 	MaxAcceptableBody int64
-	Resolver          netx.Resolver
+	Resolver          model.Resolver
 }
 
 func (h Handler) ServeHTTP(w http.ResponseWriter, req *http.Request) {

internal/cmd/oohelperd/internal/webconnectivity/webconnectivity_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"net"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -52,7 +51,7 @@ const requestWithoutDomainName = `{
 func TestWorkingAsIntended(t *testing.T) {
 	handler := Handler{
 		Client:            http.DefaultClient,
-		Dialer:            new(net.Dialer),
+		Dialer:            netxlite.DefaultDialer,
 		MaxAcceptableBody: 1 << 24,
 		Resolver:          &netxlite.ResolverSystem{},
 	}

internal/cmd/oohelperd/internal/websteps/explore.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/websteps"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	utls "gitlab.com/yawning/utls.git"
@@ -28,7 +29,7 @@ type Explorer interface {
 
 // DefaultExplorer is the default Explorer.
 type DefaultExplorer struct {
-	resolver netxlite.ResolverLegacy
+	resolver model.Resolver
 }
 
 // Explore returns a list of round trips sorted so that the first
@@ -138,8 +139,7 @@ func (e *DefaultExplorer) getH3(h3URL *h3URL, headers map[string][]string) (*htt
 	}
 	// Rationale for using log.Log here: we're already using log.Log
 	// in this package, so it seems fair to use it also here
-	transport := netxlite.NewHTTP3Transport(log.Log,
-		netxlite.NewQUICDialerFromContextDialerAdapter(dialer), tlsConf)
+	transport := netxlite.NewHTTP3Transport(log.Log, dialer, tlsConf)
 	// TODO(bassosimone): here we should use runtimex.PanicOnError
 	jarjar, _ := cookiejar.New(nil)
 	clnt := &http.Client{

internal/cmd/oohelperd/internal/websteps/generate.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/lucas-clemente/quic-go"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/websteps"
-	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 // Generate is the third step of the algorithm. Given the
@@ -22,9 +22,9 @@ type Generator interface {
 
 // DefaultGenerator is the default Generator.
 type DefaultGenerator struct {
-	dialer     netxlite.DialerLegacy
-	quicDialer netxlite.QUICContextDialer
-	resolver   netxlite.ResolverLegacy
+	dialer     model.Dialer
+	quicDialer model.QUICDialer
+	resolver   model.Resolver
 	transport  http.RoundTripper
 }
 

internal/cmd/oohelperd/internal/websteps/generate_test.go

@@ -36,6 +36,8 @@ func (d fakeQUICDialer) DialContext(ctx context.Context, network, address string
 	return nil, d.err
 }
 
+func (d fakeQUICDialer) CloseIdleConnections() {}
+
 type fakeDialer struct {
 	err error
 }
@@ -44,6 +46,8 @@ func (d fakeDialer) DialContext(ctx context.Context, network, address string) (n
 	return nil, d.err
 }
 
+func (d fakeDialer) CloseIdleConnections() {}
+
 func TestGenerateDNSFailure(t *testing.T) {
 	u, err := url.Parse("https://www.google.google")
 	runtimex.PanicOnError(err, "url.Parse failed")

internal/cmd/oohelperd/internal/websteps/initialchecks.go

@@ -5,7 +5,7 @@ import (
 	"errors"
 	"net/url"
 
-	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 // InitialChecks is the first step of the test helper algorithm. We
@@ -31,7 +31,7 @@ type InitChecker interface {
 
 // DefaultInitChecker is the default InitChecker.
 type DefaultInitChecker struct {
-	resolver netxlite.ResolverLegacy
+	resolver model.Resolver
 }
 
 // InitialChecks checks whether the URL is valid and whether the

internal/cmd/oohelperd/internal/websteps/measure.go

@@ -8,6 +8,7 @@ import (
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/websteps"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
@@ -24,7 +25,7 @@ type Config struct {
 	checker   InitChecker
 	explorer  Explorer
 	generator Generator
-	resolver  netxlite.ResolverLegacy
+	resolver  model.Resolver
 }
 
 // Measure performs the three consecutive steps of the testhelper algorithm:
@@ -90,12 +91,10 @@ func newDNSFailedResponse(err error, URL string) *ControlResponse {
 }
 
 // newResolver creates a new DNS resolver instance
-func newResolver() netxlite.ResolverLegacy {
+func newResolver() model.Resolver {
 	childResolver, err := netx.NewDNSClient(netx.Config{Logger: log.Log}, "doh://google")
 	runtimex.PanicOnError(err, "NewDNSClient failed")
-	var r netxlite.ResolverLegacy = childResolver
-	r = &netxlite.ResolverIDNA{
-		Resolver: netxlite.NewResolverLegacyAdapter(r),
-	}
+	var r model.Resolver = childResolver
+	r = &netxlite.ResolverIDNA{Resolver: r}
 	return r
 }

internal/cmd/oohelperd/oohelperd.go

@@ -13,16 +13,17 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/cmd/oohelperd/internal/websteps"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webstepsx"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
 const maxAcceptableBody = 1 << 24
 
 var (
-	dialer    netx.Dialer
+	dialer    model.Dialer
 	endpoint  = flag.String("endpoint", ":8080", "Endpoint where to listen")
 	httpx     *http.Client
-	resolver  netx.Resolver
+	resolver  model.Resolver
 	srvcancel context.CancelFunc
 	srvctx    context.Context
 	srvwg     = new(sync.WaitGroup)