refactor: merge dnsx and errorsx into netxlite (#517)

When preparing a tutorial for netxlite, I figured it is easier
to tell people "hey, this is the package you should use for all
low-level networking stuff" rather than introducing people to
a set of packages working together where some piece of functionality
is here and some other piece is there.

Part of https://github.com/ooni/probe/issues/1591

internal/netxlite/certifi.go

@@ -1,5 +1,5 @@
 // Code generated by go generate; DO NOT EDIT.
-// 2021-09-27 15:57:57.877144 +0200 CEST m=+1.353309960
+// 2021-09-28 12:05:19.526032 +0200 CEST m=+0.405934084
 // https://curl.haxx.se/ca/cacert.pem
 
 package netxlite

internal/netxlite/classify.go

@@ -1,4 +1,4 @@
-package errorsx
+package netxlite
 
 import (
 	"context"

internal/netxlite/classify_test.go

@@ -1,4 +1,4 @@
-package errorsx
+package netxlite
 
 import (
 	"context"

internal/netxlite/dialer.go

@@ -6,8 +6,6 @@ import (
 	"net"
 	"sync"
 	"time"
-
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 )
 
 // Dialer establishes network connections.
@@ -229,8 +227,7 @@ var _ Dialer = &dialerErrWrapper{}
 func (d *dialerErrWrapper) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
 	conn, err := d.Dialer.DialContext(ctx, network, address)
 	if err != nil {
-		return nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.ConnectOperation, err)
+		return nil, NewErrWrapper(ClassifyGenericError, ConnectOperation, err)
 	}
 	return &dialerErrWrapperConn{Conn: conn}, nil
 }
@@ -245,8 +242,7 @@ var _ net.Conn = &dialerErrWrapperConn{}
 func (c *dialerErrWrapperConn) Read(b []byte) (int, error) {
 	count, err := c.Conn.Read(b)
 	if err != nil {
-		return 0, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.ReadOperation, err)
+		return 0, NewErrWrapper(ClassifyGenericError, ReadOperation, err)
 	}
 	return count, nil
 }
@@ -254,8 +250,7 @@ func (c *dialerErrWrapperConn) Read(b []byte) (int, error) {
 func (c *dialerErrWrapperConn) Write(b []byte) (int, error) {
 	count, err := c.Conn.Write(b)
 	if err != nil {
-		return 0, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.WriteOperation, err)
+		return 0, NewErrWrapper(ClassifyGenericError, WriteOperation, err)
 	}
 	return count, nil
 }
@@ -263,8 +258,7 @@ func (c *dialerErrWrapperConn) Write(b []byte) (int, error) {
 func (c *dialerErrWrapperConn) Close() error {
 	err := c.Conn.Close()
 	if err != nil {
-		return errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.CloseOperation, err)
+		return NewErrWrapper(ClassifyGenericError, CloseOperation, err)
 	}
 	return nil
 }

internal/netxlite/dialer_test.go

@@ -11,7 +11,6 @@ import (
 	"time"
 
 	"github.com/apex/log"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
@@ -254,9 +253,9 @@ func TestDialerResolver(t *testing.T) {
 			mu := &sync.Mutex{}
 			errorsList := []error{
 				errors.New("a mocked error"),
-				errorsx.NewErrWrapper(
-					errorsx.ClassifyGenericError,
-					errorsx.CloseOperation,
+				NewErrWrapper(
+					ClassifyGenericError,
+					CloseOperation,
 					io.EOF,
 				),
 			}
@@ -282,7 +281,7 @@ func TestDialerResolver(t *testing.T) {
 				},
 			}
 			conn, err := d.DialContext(context.Background(), "tcp", "dot.dns:853")
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if conn != nil {
@@ -296,9 +295,9 @@ func TestDialerResolver(t *testing.T) {
 			mu := &sync.Mutex{}
 			errorsList := []error{
 				errors.New("a mocked error"),
-				errorsx.NewErrWrapper(
-					errorsx.ClassifyGenericError,
-					errorsx.CloseOperation,
+				NewErrWrapper(
+					ClassifyGenericError,
+					CloseOperation,
 					errors.New("antani"),
 				),
 			}
@@ -529,7 +528,7 @@ func TestDialerErrWrapper(t *testing.T) {
 			}
 			ctx := context.Background()
 			conn, err := d.DialContext(ctx, "", "")
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if conn != nil {
@@ -585,7 +584,7 @@ func TestDialerErrWrapperConn(t *testing.T) {
 				},
 			}
 			count, err := conn.Read(b)
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if count != 0 {
@@ -624,7 +623,7 @@ func TestDialerErrWrapperConn(t *testing.T) {
 				},
 			}
 			count, err := conn.Write(b)
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if count != 0 {
@@ -658,7 +657,7 @@ func TestDialerErrWrapperConn(t *testing.T) {
 				},
 			}
 			err := conn.Close()
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 		})

internal/netxlite/dnsdecoder.go

@@ -1,13 +1,6 @@
-package dnsx
+package netxlite
 
-import (
-	"github.com/miekg/dns"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/dnsx/model"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
-)
-
-// HTTPSSvc is an HTTPSSvc reply.
-type HTTPSSvc = model.HTTPSSvc
+import "github.com/miekg/dns"
 
 // The DNSDecoder decodes DNS replies.
 type DNSDecoder interface {
@@ -32,11 +25,11 @@ func (d *DNSDecoderMiekg) parseReply(data []byte) (*dns.Msg, error) {
 	case dns.RcodeSuccess:
 		return reply, nil
 	case dns.RcodeNameError:
-		return nil, errorsx.ErrOODNSNoSuchHost
+		return nil, ErrOODNSNoSuchHost
 	case dns.RcodeRefused:
-		return nil, errorsx.ErrOODNSRefused
+		return nil, ErrOODNSRefused
 	default:
-		return nil, errorsx.ErrOODNSMisbehaving
+		return nil, ErrOODNSMisbehaving
 	}
 }
 
@@ -66,7 +59,7 @@ func (d *DNSDecoderMiekg) DecodeHTTPS(data []byte) (*HTTPSSvc, error) {
 		}
 	}
 	if len(out.ALPN) <= 0 {
-		return nil, errorsx.ErrOODNSNoAnswer
+		return nil, ErrOODNSNoAnswer
 	}
 	return out, nil
 }
@@ -92,7 +85,7 @@ func (d *DNSDecoderMiekg) DecodeLookupHost(qtype uint16, data []byte) ([]string,
 		}
 	}
 	if len(addrs) <= 0 {
-		return nil, errorsx.ErrOODNSNoAnswer
+		return nil, ErrOODNSNoAnswer
 	}
 	return addrs, nil
 }

internal/netxlite/dnsdecoder_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"errors"
@@ -8,7 +8,6 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/miekg/dns"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 )
 
 func TestDNSDecoder(t *testing.T) {
@@ -40,7 +39,7 @@ func TestDNSDecoder(t *testing.T) {
 			d := &DNSDecoderMiekg{}
 			data, err := d.DecodeLookupHost(
 				dns.TypeA, dnsGenReplyWithError(t, dns.TypeA, dns.RcodeRefused))
-			if !errors.Is(err, errorsx.ErrOODNSRefused) {
+			if !errors.Is(err, ErrOODNSRefused) {
 				t.Fatal("not the error we expected", err)
 			}
 			if data != nil {
@@ -51,7 +50,7 @@ func TestDNSDecoder(t *testing.T) {
 		t.Run("no address", func(t *testing.T) {
 			d := &DNSDecoderMiekg{}
 			data, err := d.DecodeLookupHost(dns.TypeA, dnsGenLookupHostReplySuccess(t, dns.TypeA))
-			if !errors.Is(err, errorsx.ErrOODNSNoAnswer) {
+			if !errors.Is(err, ErrOODNSNoAnswer) {
 				t.Fatal("not the error we expected", err)
 			}
 			if data != nil {
@@ -99,7 +98,7 @@ func TestDNSDecoder(t *testing.T) {
 			d := &DNSDecoderMiekg{}
 			data, err := d.DecodeLookupHost(
 				dns.TypeA, dnsGenLookupHostReplySuccess(t, dns.TypeAAAA, "::1", "fe80::1"))
-			if !errors.Is(err, errorsx.ErrOODNSNoAnswer) {
+			if !errors.Is(err, ErrOODNSNoAnswer) {
 				t.Fatal("not the error we expected", err)
 			}
 			if data != nil {
@@ -111,7 +110,7 @@ func TestDNSDecoder(t *testing.T) {
 			d := &DNSDecoderMiekg{}
 			data, err := d.DecodeLookupHost(
 				dns.TypeAAAA, dnsGenLookupHostReplySuccess(t, dns.TypeA, "1.1.1.1", "8.8.4.4."))
-			if !errors.Is(err, errorsx.ErrOODNSNoAnswer) {
+			if !errors.Is(err, ErrOODNSNoAnswer) {
 				t.Fatal("not the error we expected", err)
 			}
 			if data != nil {
@@ -129,7 +128,7 @@ func TestDNSDecoder(t *testing.T) {
 			t.Fatal(err)
 		}
 		reply, err := d.parseReply(data)
-		if !errors.Is(err, errorsx.ErrOODNSMisbehaving) { // catch all error
+		if !errors.Is(err, ErrOODNSMisbehaving) { // catch all error
 			t.Fatal("not the error we expected", err)
 		}
 		if reply != nil {
@@ -153,7 +152,7 @@ func TestDNSDecoder(t *testing.T) {
 			data := dnsGenHTTPSReplySuccess(t, nil, nil, nil)
 			d := &DNSDecoderMiekg{}
 			reply, err := d.DecodeHTTPS(data)
-			if !errors.Is(err, errorsx.ErrOODNSNoAnswer) {
+			if !errors.Is(err, ErrOODNSNoAnswer) {
 				t.Fatal("unexpected err", err)
 			}
 			if reply != nil {

internal/netxlite/dnsencoder.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import "github.com/miekg/dns"
 

internal/netxlite/dnsencoder_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"strings"

internal/netxlite/dnsoverhttps.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"bytes"
@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/httpheader"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/iox"
 )
 
 // HTTPClient is the HTTP client expected by DNSOverHTTPS.
@@ -63,7 +62,7 @@ func (t *DNSOverHTTPS) RoundTrip(ctx context.Context, query []byte) ([]byte, err
 	if resp.Header.Get("content-type") != "application/dns-message" {
 		return nil, errors.New("doh: invalid content-type")
 	}
-	return iox.ReadAllContext(ctx, resp.Body)
+	return ReadAllContext(ctx, resp.Body)
 }
 
 // RequiresPadding returns true for DoH according to RFC8467

internal/netxlite/dnsoverhttps_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"bytes"

internal/netxlite/dnsovertcp.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"context"

internal/netxlite/dnsovertcp_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"bytes"

internal/netxlite/dnsoverudp.go

@@ -1,16 +1,10 @@
-package dnsx
+package netxlite
 
 import (
 	"context"
-	"net"
 	"time"
 )
 
-// Dialer is the network dialer interface assumed by this package.
-type Dialer interface {
-	DialContext(ctx context.Context, network, address string) (net.Conn, error)
-}
-
 // DNSOverUDP is a DNS over UDP RoundTripper.
 type DNSOverUDP struct {
 	dialer  Dialer

internal/netxlite/dnsoverudp_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"bytes"
@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
@@ -147,7 +148,7 @@ func TestDNSOverUDP(t *testing.T) {
 
 	t.Run("other functions okay", func(t *testing.T) {
 		const address = "9.9.9.9:53"
-		txp := NewDNSOverUDP(&net.Dialer{}, address)
+		txp := NewDNSOverUDP(NewDialerWithoutResolver(log.Log), address)
 		if txp.RequiresPadding() != false {
 			t.Fatal("invalid RequiresPadding")
 		}

internal/netxlite/dnstransport.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import "context"
 

internal/netxlite/dnsx/dnsx.go

@@ -1,5 +1,5 @@
-// Package model contains the dnsx model.
-package model
+// Package dnsx contains the dnsx model.
+package dnsx
 
 // HTTPSSvc is an HTTPSSvc reply.
 type HTTPSSvc struct {

internal/netxlite/dnsx/mocks/doc.go

@@ -1,2 +0,0 @@
-// Package mocks contains mocks for dnsx.
-package mocks

internal/netxlite/errno.go

@@ -1,7 +1,7 @@
 // Code generated by go generate; DO NOT EDIT.
-// Generated: 2021-09-27 15:57:58.500515 +0200 CEST m=+0.304199251
+// Generated: 2021-09-28 12:05:19.868647 +0200 CEST m=+0.105301959
 
-package errorsx
+package netxlite
 
 //go:generate go run ./internal/generrno/
 

internal/netxlite/errno_test.go

@@ -1,7 +1,7 @@
 // Code generated by go generate; DO NOT EDIT.
-// Generated: 2021-09-27 15:57:58.553101 +0200 CEST m=+0.356786917
+// Generated: 2021-09-28 12:05:19.918073 +0200 CEST m=+0.154728959
 
-package errorsx
+package netxlite
 
 import (
 	"io"

internal/netxlite/errno_unix.go

@@ -1,7 +1,7 @@
 // Code generated by go generate; DO NOT EDIT.
-// Generated: 2021-09-27 15:57:58.197535 +0200 CEST m=+0.001212709
+// Generated: 2021-09-28 12:05:19.763535 +0200 CEST m=+0.000187668
 
-package errorsx
+package netxlite
 
 import "golang.org/x/sys/unix"
 

internal/netxlite/errno_windows.go

@@ -1,7 +1,7 @@
 // Code generated by go generate; DO NOT EDIT.
-// Generated: 2021-09-27 15:57:58.455744 +0200 CEST m=+0.259427834
+// Generated: 2021-09-28 12:05:19.843209 +0200 CEST m=+0.079863168
 
-package errorsx
+package netxlite
 
 import "golang.org/x/sys/windows"
 

internal/netxlite/errorsx/doc.go

@@ -1,20 +0,0 @@
-// Package errorsx contains code to classify errors.
-//
-// We define the ErrWrapper type, that should wrap any error
-// and map it to the corresponding OONI failure.
-//
-// See https://github.com/ooni/spec/blob/master/data-formats/df-007-errors.md
-// for a list of OONI failure strings.
-//
-// We define ClassifyXXX functions that map an `error` type to
-// the corresponding OONI failure.
-//
-// When we cannot map an error to an OONI failure we return
-// an "unknown_failure: XXX" string where the XXX part has
-// been scrubbed so to remove any network endpoints.
-//
-// The general approach we have been following for this
-// package has been to return the same strings that we used
-// with the previous measurement engine, Measurement Kit
-// available at https://github.com/measurement-kit/measurement-kit.
-package errorsx

internal/netxlite/errwrapper.go

@@ -1,4 +1,4 @@
-package errorsx
+package netxlite
 
 import "encoding/json"
 

internal/netxlite/errwrapper_test.go

@@ -1,4 +1,4 @@
-package errorsx
+package netxlite
 
 import (
 	"encoding/json"

internal/netxlite/http_test.go

@@ -13,7 +13,6 @@ import (
 	"github.com/apex/log"
 	oohttp "github.com/ooni/oohttp"
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/iox"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
@@ -84,7 +83,7 @@ func TestHTTPTransportLogger(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			iox.ReadAllContext(context.Background(), resp.Body)
+			ReadAllContext(context.Background(), resp.Body)
 			resp.Body.Close()
 			if count < 1 {
 				t.Fatal("no logs?!")

internal/netxlite/internal/gencertifi/main.go

@@ -19,7 +19,7 @@ import (
 	"text/template"
 	"time"
 
-	"github.com/ooni/probe-cli/v3/internal/netxlite/iox"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
 
 var tmpl = template.Must(template.New("").Parse(`// Code generated by go generate; DO NOT EDIT.
@@ -50,7 +50,7 @@ func main() {
 	}
 	defer resp.Body.Close()
 
-	bundle, err := iox.ReadAllContext(context.Background(), resp.Body)
+	bundle, err := netxlite.ReadAllContext(context.Background(), resp.Body)
 	if err != nil {
 		log.Fatal(err)
 	}

internal/netxlite/internal/generrno/main.go

@@ -143,7 +143,7 @@ func writeSystemSpecificFile(kind string) {
 	filep := fileCreate(filename)
 	fileWrite(filep, "// Code generated by go generate; DO NOT EDIT.\n")
 	filePrintf(filep, "// Generated: %+v\n\n", time.Now())
-	fileWrite(filep, "package errorsx\n\n")
+	fileWrite(filep, "package netxlite\n\n")
 	filePrintf(filep, "import \"golang.org/x/sys/%s\"\n\n", kind)
 	fileWrite(filep, "const (\n")
 	for _, spec := range Specs {
@@ -163,7 +163,7 @@ func writeGenericFile() {
 	filep := fileCreate(filename)
 	fileWrite(filep, "// Code generated by go generate; DO NOT EDIT.\n")
 	filePrintf(filep, "// Generated: %+v\n\n", time.Now())
-	fileWrite(filep, "package errorsx\n\n")
+	fileWrite(filep, "package netxlite\n\n")
 	fileWrite(filep, "//go:generate go run ./internal/generrno/\n\n")
 	fileWrite(filep, "import (\n")
 	fileWrite(filep, "\t\"errors\"\n")
@@ -237,7 +237,7 @@ func writeGenericTestFile() {
 
 	fileWrite(filep, "// Code generated by go generate; DO NOT EDIT.\n")
 	filePrintf(filep, "// Generated: %+v\n\n", time.Now())
-	fileWrite(filep, "package errorsx\n\n")
+	fileWrite(filep, "package netxlite\n\n")
 	fileWrite(filep, "import (\n")
 	fileWrite(filep, "\t\"io\"\n")
 	fileWrite(filep, "\t\"syscall\"\n")

internal/netxlite/iox.go

@@ -1,5 +1,4 @@
-// Package iox contains io extensions.
-package iox
+package netxlite
 
 import (
 	"context"

internal/netxlite/iox/example_test.go

@@ -1,21 +0,0 @@
-package iox_test
-
-import (
-	"context"
-	"fmt"
-	"log"
-	"strings"
-
-	"github.com/ooni/probe-cli/v3/internal/netxlite/iox"
-)
-
-func ExampleReadAllContext() {
-	r := strings.NewReader("deadbeef")
-	ctx := context.Background()
-	out, err := iox.ReadAllContext(ctx, r)
-	if err != nil {
-		log.Fatal(err)
-	}
-	fmt.Printf("%d\n", len(out))
-	// Output: 8
-}

internal/netxlite/iox_test.go

@@ -1,4 +1,4 @@
-package iox
+package netxlite
 
 import (
 	"context"

internal/netxlite/mocks/dnsdecoder.go

@@ -1,9 +1,9 @@
 package mocks
 
-import "github.com/ooni/probe-cli/v3/internal/netxlite/dnsx/model"
+import "github.com/ooni/probe-cli/v3/internal/netxlite/dnsx"
 
 // HTTPSSvc is the result of HTTPS queries.
-type HTTPSSvc = model.HTTPSSvc
+type HTTPSSvc = dnsx.HTTPSSvc
 
 // DNSDecoder allows mocking dnsx.DNSDecoder.
 type DNSDecoder struct {

internal/netxlite/mocks/resolver.go

@@ -2,8 +2,6 @@ package mocks
 
 import (
 	"context"
-
-	"github.com/ooni/probe-cli/v3/internal/netxlite/dnsx/model"
 )
 
 // Resolver is a mockable Resolver.
@@ -35,9 +33,6 @@ func (r *Resolver) CloseIdleConnections() {
 	r.MockCloseIdleConnections()
 }
 
-// HTTPSSvc is an HTTPSSvc reply.
-type HTTPSSvc = model.HTTPSSvc
-
 // LookupHTTPS calls MockLookupHTTPS.
 func (r *Resolver) LookupHTTPS(ctx context.Context, domain string) (*HTTPSSvc, error) {
 	return r.MockLookupHTTPS(ctx, domain)

internal/netxlite/operations.go

@@ -1,4 +1,4 @@
-package errorsx
+package netxlite
 
 // Operations that we measure. They are the possibly values of
 // the ErrWrapper.Operation field.

internal/netxlite/quic.go

@@ -9,7 +9,6 @@ import (
 	"sync"
 
 	"github.com/lucas-clemente/quic-go"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/quicx"
 )
 
@@ -360,8 +359,7 @@ var _ QUICListener = &quicListenerErrWrapper{}
 func (qls *quicListenerErrWrapper) Listen(addr *net.UDPAddr) (quicx.UDPLikeConn, error) {
 	pconn, err := qls.QUICListener.Listen(addr)
 	if err != nil {
-		return nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.QUICListenOperation, err)
+		return nil, NewErrWrapper(ClassifyGenericError, QUICListenOperation, err)
 	}
 	return &quicErrWrapperUDPLikeConn{pconn}, nil
 }
@@ -378,8 +376,7 @@ var _ quicx.UDPLikeConn = &quicErrWrapperUDPLikeConn{}
 func (c *quicErrWrapperUDPLikeConn) WriteTo(p []byte, addr net.Addr) (int, error) {
 	count, err := c.UDPLikeConn.WriteTo(p, addr)
 	if err != nil {
-		return 0, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.WriteToOperation, err)
+		return 0, NewErrWrapper(ClassifyGenericError, WriteToOperation, err)
 	}
 	return count, nil
 }
@@ -388,8 +385,7 @@ func (c *quicErrWrapperUDPLikeConn) WriteTo(p []byte, addr net.Addr) (int, error
 func (c *quicErrWrapperUDPLikeConn) ReadFrom(b []byte) (int, net.Addr, error) {
 	n, addr, err := c.UDPLikeConn.ReadFrom(b)
 	if err != nil {
-		return 0, nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.ReadFromOperation, err)
+		return 0, nil, NewErrWrapper(ClassifyGenericError, ReadFromOperation, err)
 	}
 	return n, addr, nil
 }
@@ -398,8 +394,7 @@ func (c *quicErrWrapperUDPLikeConn) ReadFrom(b []byte) (int, net.Addr, error) {
 func (c *quicErrWrapperUDPLikeConn) Close() error {
 	err := c.UDPLikeConn.Close()
 	if err != nil {
-		return errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError, errorsx.ReadFromOperation, err)
+		return NewErrWrapper(ClassifyGenericError, ReadFromOperation, err)
 	}
 	return nil
 }
@@ -415,8 +410,8 @@ func (d *quicDialerErrWrapper) DialContext(
 	tlsCfg *tls.Config, cfg *quic.Config) (quic.EarlySession, error) {
 	sess, err := d.QUICDialer.DialContext(ctx, network, host, tlsCfg, cfg)
 	if err != nil {
-		return nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyQUICHandshakeError, errorsx.QUICHandshakeOperation, err)
+		return nil, NewErrWrapper(
+			ClassifyQUICHandshakeError, QUICHandshakeOperation, err)
 	}
 	return sess, nil
 }

internal/netxlite/quic_test.go

@@ -12,7 +12,6 @@ import (
 	"github.com/apex/log"
 	"github.com/google/go-cmp/cmp"
 	"github.com/lucas-clemente/quic-go"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/quicx"
 )
@@ -524,7 +523,7 @@ func TestQUICListenerErrWrapper(t *testing.T) {
 				},
 			}
 			conn, err := ql.Listen(&net.UDPAddr{})
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if conn != nil {
@@ -569,7 +568,7 @@ func TestQUICErrWrapperUDPLikeConn(t *testing.T) {
 				},
 			}
 			count, addr, err := conn.ReadFrom(p)
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if count != 0 {
@@ -611,7 +610,7 @@ func TestQUICErrWrapperUDPLikeConn(t *testing.T) {
 				},
 			}
 			count, err := conn.WriteTo(p, &net.UDPAddr{})
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if count != 0 {
@@ -645,7 +644,7 @@ func TestQUICErrWrapperUDPLikeConn(t *testing.T) {
 				},
 			}
 			err := conn.Close()
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 		})
@@ -699,7 +698,7 @@ func TestQUICDialerErrWrapper(t *testing.T) {
 			}
 			ctx := context.Background()
 			sess, err := d.DialContext(ctx, "", "", &tls.Config{}, &quic.Config{})
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if sess != nil {

internal/netxlite/quirks.go

@@ -3,8 +3,6 @@ package netxlite
 import (
 	"errors"
 	"strings"
-
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 )
 
 // This file contains weird stuff that we carried over from
@@ -36,7 +34,7 @@ func quirkReduceErrors(errorslist []error) error {
 		return nil
 	}
 	for _, err := range errorslist {
-		var wrapper *errorsx.ErrWrapper
+		var wrapper *ErrWrapper
 		if errors.As(err, &wrapper) && !strings.HasPrefix(
 			err.Error(), "unknown_failure",
 		) {

internal/netxlite/quirks_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 )
 
 func TestQuirkReduceErrors(t *testing.T) {
@@ -35,19 +34,19 @@ func TestQuirkReduceErrors(t *testing.T) {
 
 	t.Run("multiple errors with meaningful ones", func(t *testing.T) {
 		err1 := errors.New("mocked error #1")
-		err2 := errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError,
-			errorsx.CloseOperation,
+		err2 := NewErrWrapper(
+			ClassifyGenericError,
+			CloseOperation,
 			errors.New("antani"),
 		)
-		err3 := errorsx.NewErrWrapper(
-			errorsx.ClassifyGenericError,
-			errorsx.CloseOperation,
-			errorsx.ECONNREFUSED,
+		err3 := NewErrWrapper(
+			ClassifyGenericError,
+			CloseOperation,
+			ECONNREFUSED,
 		)
 		err4 := errors.New("mocked error #3")
 		result := quirkReduceErrors([]error{err1, err2, err3, err4})
-		if result.Error() != errorsx.FailureConnectionRefused {
+		if result.Error() != FailureConnectionRefused {
 			t.Fatal("wrong result")
 		}
 	})

internal/netxlite/resolver.go

@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/netxlite/dnsx"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"golang.org/x/net/idna"
 )
 
@@ -253,8 +252,7 @@ var _ Resolver = &resolverErrWrapper{}
 func (r *resolverErrWrapper) LookupHost(ctx context.Context, hostname string) ([]string, error) {
 	addrs, err := r.Resolver.LookupHost(ctx, hostname)
 	if err != nil {
-		return nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyResolverError, errorsx.ResolveOperation, err)
+		return nil, NewErrWrapper(ClassifyResolverError, ResolveOperation, err)
 	}
 	return addrs, nil
 }
@@ -263,8 +261,7 @@ func (r *resolverErrWrapper) LookupHTTPS(
 	ctx context.Context, domain string) (*HTTPSSvc, error) {
 	out, err := r.Resolver.LookupHTTPS(ctx, domain)
 	if err != nil {
-		return nil, errorsx.NewErrWrapper(
-			errorsx.ClassifyResolverError, errorsx.ResolveOperation, err)
+		return nil, NewErrWrapper(ClassifyResolverError, ResolveOperation, err)
 	}
 	return out, nil
 }

internal/netxlite/resolver_test.go

@@ -11,7 +11,6 @@ import (
 
 	"github.com/apex/log"
 	"github.com/google/go-cmp/cmp"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
@@ -493,7 +492,7 @@ func TestResolverErrWrapper(t *testing.T) {
 			}
 			ctx := context.Background()
 			addrs, err := reso.LookupHost(ctx, "")
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if addrs != nil {
@@ -578,7 +577,7 @@ func TestResolverErrWrapper(t *testing.T) {
 			}
 			ctx := context.Background()
 			https, err := reso.LookupHTTPS(ctx, "")
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if https != nil {

internal/netxlite/serialresolver.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"context"

internal/netxlite/serialresolver_test.go

@@ -1,4 +1,4 @@
-package dnsx
+package netxlite
 
 import (
 	"context"
@@ -9,8 +9,7 @@ import (
 
 	"github.com/miekg/dns"
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/dnsx/mocks"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
+	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
 func TestSerialResolver(t *testing.T) {
@@ -81,7 +80,7 @@ func TestSerialResolver(t *testing.T) {
 			}
 			r := NewSerialResolver(txp)
 			addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
-			if !errors.Is(err, errorsx.ErrOODNSNoAnswer) {
+			if !errors.Is(err, ErrOODNSNoAnswer) {
 				t.Fatal("not the error we expected", err)
 			}
 			if addrs != nil {
@@ -130,7 +129,7 @@ func TestSerialResolver(t *testing.T) {
 		t.Run("with timeout", func(t *testing.T) {
 			txp := &mocks.DNSTransport{
 				MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
-					return nil, &net.OpError{Err: errorsx.ETIMEDOUT, Op: "dial"}
+					return nil, &net.OpError{Err: ETIMEDOUT, Op: "dial"}
 				},
 				MockRequiresPadding: func() bool {
 					return true
@@ -138,7 +137,7 @@ func TestSerialResolver(t *testing.T) {
 			}
 			r := NewSerialResolver(txp)
 			addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
-			if !errors.Is(err, errorsx.ETIMEDOUT) {
+			if !errors.Is(err, ETIMEDOUT) {
 				t.Fatal("not the error we expected")
 			}
 			if addrs != nil {

internal/netxlite/tls.go

@@ -10,7 +10,6 @@ import (
 	"time"
 
 	oohttp "github.com/ooni/oohttp"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 )
 
 var (
@@ -346,8 +345,8 @@ func (h *tlsHandshakerErrWrapper) Handshake(
 ) (net.Conn, tls.ConnectionState, error) {
 	tlsconn, state, err := h.TLSHandshaker.Handshake(ctx, conn, config)
 	if err != nil {
-		return nil, tls.ConnectionState{}, errorsx.NewErrWrapper(
-			errorsx.ClassifyTLSHandshakeError, errorsx.TLSHandshakeOperation, err)
+		return nil, tls.ConnectionState{}, NewErrWrapper(
+			ClassifyTLSHandshakeError, TLSHandshakeOperation, err)
 	}
 	return tlsconn, state, nil
 }

internal/netxlite/tls_test.go

@@ -16,7 +16,6 @@ import (
 
 	"github.com/apex/log"
 	"github.com/google/go-cmp/cmp"
-	"github.com/ooni/probe-cli/v3/internal/netxlite/errorsx"
 	"github.com/ooni/probe-cli/v3/internal/netxlite/mocks"
 )
 
@@ -544,7 +543,7 @@ func TestTLSHandshakerErrWrapper(t *testing.T) {
 			}
 			ctx := context.Background()
 			conn, _, err := th.Handshake(ctx, &mocks.Conn{}, &tls.Config{})
-			if err == nil || err.Error() != errorsx.FailureEOFError {
+			if err == nil || err.Error() != FailureEOFError {
 				t.Fatal("unexpected err", err)
 			}
 			if conn != nil {