feat: introduce the tlsping experiment (#716)

See https://github.com/ooni/probe/issues/2088 (issue) and https://github.com/ooni/spec/pull/236 (spec).

internal/engine/allexperiments.go

@@ -20,6 +20,7 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/stunreachability"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/tcpping"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/telegram"
+	"github.com/ooni/probe-cli/v3/internal/engine/experiment/tlsping"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/tlstool"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/tor"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/torsf"
@@ -228,6 +229,18 @@ var experimentsByName = map[string]func(*Session) *ExperimentBuilder{
 		}
 	},
 
+	"tlsping": func(session *Session) *ExperimentBuilder {
+		return &ExperimentBuilder{
+			build: func(config interface{}) *Experiment {
+				return NewExperiment(session, tlsping.NewExperimentMeasurer(
+					*config.(*tlsping.Config),
+				))
+			},
+			config:      &tlsping.Config{},
+			inputPolicy: InputStrictlyRequired,
+		}
+	},
+
 	"telegram": func(session *Session) *ExperimentBuilder {
 		return &ExperimentBuilder{
 			build: func(config interface{}) *Experiment {

internal/engine/experiment/tcpping/tcpping.go

@@ -135,6 +135,7 @@ func (m *Measurer) tcpPingAsync(ctx context.Context, mxmx *measurex.Measurer,
 // tcpConnect performs a TCP connect and returns the result to the caller.
 func (m *Measurer) tcpConnect(ctx context.Context, mxmx *measurex.Measurer,
 	address string) *measurex.EndpointMeasurement {
+	// TODO(bassosimone): make the timeout user-configurable
 	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
 	defer cancel()
 	return mxmx.TCPConnect(ctx, address)

internal/engine/experiment/tlsping/tlsping.go

@@ -0,0 +1,188 @@
+// Package tlsping is the experimental tlsping experiment.
+//
+// See https://github.com/ooni/spec/blob/master/nettests/ts-033-tlsping.md.
+package tlsping
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/ooni/probe-cli/v3/internal/measurex"
+	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
+)
+
+const (
+	testName    = "tlsping"
+	testVersion = "0.1.0"
+)
+
+// Config contains the experiment configuration.
+type Config struct {
+	// ALPN allows to specify which ALPN or ALPNs to send.
+	ALPN string `ooni:"space separated list of ALPNs to use"`
+
+	// Delay is the delay between each repetition (in milliseconds).
+	Delay int64 `ooni:"number of milliseconds to wait before sending each ping"`
+
+	// Repetitions is the number of repetitions for each ping.
+	Repetitions int64 `ooni:"number of times to repeat the measurement"`
+
+	// SNI is the SNI value to use.
+	SNI string `ooni:"the SNI value to use"`
+}
+
+func (c *Config) alpn() string {
+	if c.ALPN != "" {
+		return c.ALPN
+	}
+	return "h2 http/1.1"
+}
+
+func (c *Config) delay() time.Duration {
+	if c.Delay > 0 {
+		return time.Duration(c.Delay) * time.Millisecond
+	}
+	return time.Second
+}
+
+func (c *Config) repetitions() int64 {
+	if c.Repetitions > 0 {
+		return c.Repetitions
+	}
+	return 10
+}
+
+// TestKeys contains the experiment results.
+type TestKeys struct {
+	Pings []*SinglePing `json:"pings"`
+}
+
+// SinglePing contains the results of a single ping.
+type SinglePing struct {
+	NetworkEvents []*measurex.ArchivalNetworkEvent          `json:"network_events"`
+	TCPConnect    []*measurex.ArchivalTCPConnect            `json:"tcp_connect"`
+	TLSHandshake  []*measurex.ArchivalQUICTLSHandshakeEvent `json:"tls_handshakes"`
+}
+
+// Measurer performs the measurement.
+type Measurer struct {
+	config Config
+}
+
+// ExperimentName implements ExperimentMeasurer.ExperiExperimentName.
+func (m *Measurer) ExperimentName() string {
+	return testName
+}
+
+// ExperimentVersion implements ExperimentMeasurer.ExperimentVersion.
+func (m *Measurer) ExperimentVersion() string {
+	return testVersion
+}
+
+var (
+	// errNoInputProvided indicates you didn't provide any input
+	errNoInputProvided = errors.New("not input provided")
+
+	// errInputIsNotAnURL indicates that input is not an URL
+	errInputIsNotAnURL = errors.New("input is not an URL")
+
+	// errInvalidScheme indicates that the scheme is invalid
+	errInvalidScheme = errors.New("scheme must be tlshandshake")
+
+	// errMissingPort indicates that there is no port.
+	errMissingPort = errors.New("the URL must include a port")
+)
+
+// Run implements ExperimentMeasurer.Run.
+func (m *Measurer) Run(
+	ctx context.Context,
+	sess model.ExperimentSession,
+	measurement *model.Measurement,
+	callbacks model.ExperimentCallbacks,
+) error {
+	if measurement.Input == "" {
+		return errNoInputProvided
+	}
+	parsed, err := url.Parse(string(measurement.Input))
+	if err != nil {
+		return fmt.Errorf("%w: %s", errInputIsNotAnURL, err.Error())
+	}
+	if parsed.Scheme != "tlshandshake" {
+		return errInvalidScheme
+	}
+	if parsed.Port() == "" {
+		return errMissingPort
+	}
+	if m.config.SNI == "" {
+		sess.Logger().Warn("no -O SNI=<SNI> specified from command line")
+	}
+	tk := new(TestKeys)
+	measurement.TestKeys = tk
+	out := make(chan *measurex.EndpointMeasurement)
+	mxmx := measurex.NewMeasurerWithDefaultSettings()
+	go m.tlsPingLoop(ctx, mxmx, parsed.Host, out)
+	for len(tk.Pings) < int(m.config.repetitions()) {
+		meas := <-out
+		tk.Pings = append(tk.Pings, &SinglePing{
+			NetworkEvents: measurex.NewArchivalNetworkEventList(meas.ReadWrite),
+			TCPConnect:    measurex.NewArchivalTCPConnectList(meas.Connect),
+			TLSHandshake:  measurex.NewArchivalQUICTLSHandshakeEventList(meas.TLSHandshake),
+		})
+	}
+	return nil // return nil so we always submit the measurement
+}
+
+// tlsPingLoop sends all the ping requests and emits the results onto the out channel.
+func (m *Measurer) tlsPingLoop(ctx context.Context, mxmx *measurex.Measurer,
+	address string, out chan<- *measurex.EndpointMeasurement) {
+	ticker := time.NewTicker(m.config.delay())
+	defer ticker.Stop()
+	for i := int64(0); i < m.config.repetitions(); i++ {
+		go m.tlsPingAsync(ctx, mxmx, address, out)
+		<-ticker.C
+	}
+}
+
+// tlsPingAsync performs a TLS ping and emits the result onto the out channel.
+func (m *Measurer) tlsPingAsync(ctx context.Context, mxmx *measurex.Measurer,
+	address string, out chan<- *measurex.EndpointMeasurement) {
+	out <- m.tlsConnectAndHandshake(ctx, mxmx, address)
+}
+
+// tlsConnectAndHandshake performs a TCP connect followed by a TLS handshake
+// and returns the results of these operations to the caller.
+func (m *Measurer) tlsConnectAndHandshake(ctx context.Context, mxmx *measurex.Measurer,
+	address string) *measurex.EndpointMeasurement {
+	// TODO(bassosimone): make the timeout user-configurable
+	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
+	defer cancel()
+	return mxmx.TLSConnectAndHandshake(ctx, address, &tls.Config{
+		NextProtos: strings.Split(m.config.alpn(), " "),
+		RootCAs:    netxlite.NewDefaultCertPool(),
+		ServerName: m.config.SNI,
+	})
+}
+
+// NewExperimentMeasurer creates a new ExperimentMeasurer.
+func NewExperimentMeasurer(config Config) model.ExperimentMeasurer {
+	return &Measurer{config: config}
+}
+
+// SummaryKeys contains summary keys for this experiment.
+//
+// Note that this structure is part of the ABI contract with ooniprobe
+// therefore we should be careful when changing it.
+type SummaryKeys struct {
+	IsAnomaly bool `json:"-"`
+}
+
+// GetSummaryKeys implements model.ExperimentMeasurer.GetSummaryKeys.
+func (m Measurer) GetSummaryKeys(measurement *model.Measurement) (interface{}, error) {
+	return SummaryKeys{IsAnomaly: false}, nil
+}

internal/engine/experiment/tlsping/tlsping_test.go

@@ -0,0 +1,121 @@
+package tlsping
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
+	"github.com/ooni/probe-cli/v3/internal/model"
+)
+
+func TestConfig_alpn(t *testing.T) {
+	c := Config{}
+	if c.alpn() != "h2 http/1.1" {
+		t.Fatal("invalid default alpn list")
+	}
+}
+
+func TestConfig_repetitions(t *testing.T) {
+	c := Config{}
+	if c.repetitions() != 10 {
+		t.Fatal("invalid default number of repetitions")
+	}
+}
+
+func TestConfig_delay(t *testing.T) {
+	c := Config{}
+	if c.delay() != time.Second {
+		t.Fatal("invalid default delay")
+	}
+}
+
+func TestMeasurer_run(t *testing.T) {
+	// expectedPings is the expected number of pings
+	const expectedPings = 4
+
+	// runHelper is an helper function to run this set of tests.
+	runHelper := func(input string) (*model.Measurement, model.ExperimentMeasurer, error) {
+		m := NewExperimentMeasurer(Config{
+			ALPN:        "http/1.1",
+			Delay:       1, // millisecond
+			Repetitions: expectedPings,
+		})
+		if m.ExperimentName() != "tlsping" {
+			t.Fatal("invalid experiment name")
+		}
+		if m.ExperimentVersion() != "0.1.0" {
+			t.Fatal("invalid experiment version")
+		}
+		ctx := context.Background()
+		meas := &model.Measurement{
+			Input: model.MeasurementTarget(input),
+		}
+		sess := &mockable.Session{
+			MockableLogger: model.DiscardLogger,
+		}
+		callbacks := model.NewPrinterCallbacks(model.DiscardLogger)
+		err := m.Run(ctx, sess, meas, callbacks)
+		return meas, m, err
+	}
+
+	t.Run("with empty input", func(t *testing.T) {
+		_, _, err := runHelper("")
+		if !errors.Is(err, errNoInputProvided) {
+			t.Fatal("unexpected error", err)
+		}
+	})
+
+	t.Run("with invalid URL", func(t *testing.T) {
+		_, _, err := runHelper("\t")
+		if !errors.Is(err, errInputIsNotAnURL) {
+			t.Fatal("unexpected error", err)
+		}
+	})
+
+	t.Run("with invalid scheme", func(t *testing.T) {
+		_, _, err := runHelper("https://8.8.8.8:443/")
+		if !errors.Is(err, errInvalidScheme) {
+			t.Fatal("unexpected error", err)
+		}
+	})
+
+	t.Run("with missing port", func(t *testing.T) {
+		_, _, err := runHelper("tlshandshake://8.8.8.8")
+		if !errors.Is(err, errMissingPort) {
+			t.Fatal("unexpected error", err)
+		}
+	})
+
+	t.Run("with local listener", func(t *testing.T) {
+		srvr := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(200)
+		}))
+		defer srvr.Close()
+		URL, err := url.Parse(srvr.URL)
+		if err != nil {
+			t.Fatal(err)
+		}
+		URL.Scheme = "tlshandshake"
+		meas, m, err := runHelper(URL.String())
+		if err != nil {
+			t.Fatal(err)
+		}
+		tk := meas.TestKeys.(*TestKeys)
+		if len(tk.Pings) != expectedPings {
+			t.Fatal("unexpected number of pings")
+		}
+		ask, err := m.GetSummaryKeys(meas)
+		if err != nil {
+			t.Fatal("cannot obtain summary")
+		}
+		summary := ask.(SummaryKeys)
+		if summary.IsAnomaly {
+			t.Fatal("expected no anomaly")
+		}
+	})
+}