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refactor: DNSTransport I/Os DNS messages (#760)

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This diff refactors the DNSTransport model to receive in input a DNSQuery and return in output a DNSResponse.

The design of DNSQuery and DNSResponse takes into account the use case of a transport using getaddrinfo, meaning that we don't need to serialize and deserialize messages when using getaddrinfo.

The current codebase does not use a getaddrinfo transport, but I wrote one such a transport in the Websteps Winter 2021 prototype (https://github.com/bassosimone/websteps-illustrated/).

The design conversation that lead to producing this diff is https://github.com/ooni/probe/issues/2099
This commit is contained in:
Simone Basso
2022-05-25 17:03:58 +02:00
committed by GitHub
parent 7a0a156aec
commit 01a513a496
35 changed files with 1731 additions and 1076 deletions
Download Patch File Download Diff File Expand all files Collapse all files
internal/engine/netx/netx.go
+1 -1
View File
@@ -317,7 +317,7 @@ func NewDNSClientWithOverrides(config Config, URL, hostOverride, SNIOverride,
if err != nil {
return nil, err
}
var txp model.DNSTransport = netxlite.NewDNSOverTLS(
var txp model.DNSTransport = netxlite.NewDNSOverTLSTransport(
tlsDialer.DialTLSContext, endpoint)
if config.ResolveSaver != nil {
txp = resolver.SaverDNSTransport{
internal/engine/netx/resolver/fake_test.go
-34
View File
@@ -76,40 +76,6 @@ func (c *FakeConn) SetWriteDeadline(t time.Time) (err error) {
return c.SetWriteDeadlineError
}
type FakeTransport struct {
Data []byte
Err error
}
func (ft FakeTransport) RoundTrip(ctx context.Context, query []byte) ([]byte, error) {
return ft.Data, ft.Err
}
func (ft FakeTransport) RequiresPadding() bool {
return false
}
func (ft FakeTransport) Address() string {
return ""
}
func (ft FakeTransport) Network() string {
return "fake"
}
func (fk FakeTransport) CloseIdleConnections() {
// nothing to do
}
type FakeEncoder struct {
Data []byte
Err error
}
func (fe FakeEncoder) Encode(domain string, qtype uint16, padding bool) ([]byte, error) {
return fe.Data, fe.Err
}
func NewFakeResolverThatFails() model.Resolver {
return NewFakeResolverWithExplicitError(netxlite.ErrOODNSNoSuchHost)
}
internal/engine/netx/resolver/integration_test.go
+2 -2
View File
@@ -99,14 +99,14 @@ func TestNewResolverTCPDomain(t *testing.T) {
func TestNewResolverDoTAddress(t *testing.T) {
reso := netxlite.NewSerialResolver(
netxlite.NewDNSOverTLS(new(tls.Dialer).DialContext, "8.8.8.8:853"))
netxlite.NewDNSOverTLSTransport(new(tls.Dialer).DialContext, "8.8.8.8:853"))
testresolverquick(t, reso)
testresolverquickidna(t, reso)
}
func TestNewResolverDoTDomain(t *testing.T) {
reso := netxlite.NewSerialResolver(
netxlite.NewDNSOverTLS(new(tls.Dialer).DialContext, "dns.google.com:853"))
netxlite.NewDNSOverTLSTransport(new(tls.Dialer).DialContext, "dns.google.com:853"))
testresolverquick(t, reso)
testresolverquickidna(t, reso)
}
internal/engine/netx/resolver/saver.go
+19 -6
View File
@@ -46,28 +46,41 @@ type SaverDNSTransport struct {
}
// RoundTrip implements RoundTripper.RoundTrip
func (txp SaverDNSTransport) RoundTrip(ctx context.Context, query []byte) ([]byte, error) {
func (txp SaverDNSTransport) RoundTrip(
ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
start := time.Now()
txp.Saver.Write(trace.Event{
Address: txp.Address(),
DNSQuery: query,
DNSQuery: txp.maybeQueryBytes(query),
Name: "dns_round_trip_start",
Proto: txp.Network(),
Time: start,
})
reply, err := txp.DNSTransport.RoundTrip(ctx, query)
response, err := txp.DNSTransport.RoundTrip(ctx, query)
stop := time.Now()
txp.Saver.Write(trace.Event{
Address: txp.Address(),
DNSQuery: query,
DNSReply: reply,
DNSQuery: txp.maybeQueryBytes(query),
DNSReply: txp.maybeResponseBytes(response),
Duration: stop.Sub(start),
Err: err,
Name: "dns_round_trip_done",
Proto: txp.Network(),
Time: stop,
})
return reply, err
return response, err
}
func (txp SaverDNSTransport) maybeQueryBytes(query model.DNSQuery) []byte {
data, _ := query.Bytes()
return data
}
func (txp SaverDNSTransport) maybeResponseBytes(response model.DNSResponse) []byte {
if response == nil {
return nil
}
return response.Bytes()
}
var _ model.Resolver = SaverResolver{}
internal/engine/netx/resolver/saver_test.go
+45 -12
View File
@@ -10,6 +10,8 @@ import (
"github.com/ooni/probe-cli/v3/internal/engine/netx/resolver"
"github.com/ooni/probe-cli/v3/internal/engine/netx/trace"
"github.com/ooni/probe-cli/v3/internal/model"
"github.com/ooni/probe-cli/v3/internal/model/mocks"
)
func TestSaverResolverFailure(t *testing.T) {
@@ -110,12 +112,25 @@ func TestSaverDNSTransportFailure(t *testing.T) {
expected := errors.New("no such host")
saver := &trace.Saver{}
txp := resolver.SaverDNSTransport{
DNSTransport: resolver.FakeTransport{
Err: expected,
DNSTransport: &mocks.DNSTransport{
MockRoundTrip: func(ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
return nil, expected
},
MockNetwork: func() string {
return "fake"
},
MockAddress: func() string {
return ""
},
},
Saver: saver,
}
query := []byte("abc")
rawQuery := []byte{0xde, 0xad, 0xbe, 0xef}
query := &mocks.DNSQuery{
MockBytes: func() ([]byte, error) {
return rawQuery, nil
},
}
reply, err := txp.RoundTrip(context.Background(), query)
if !errors.Is(err, expected) {
t.Fatal("not the error we expected")
@@ -127,7 +142,7 @@ func TestSaverDNSTransportFailure(t *testing.T) {
if len(ev) != 2 {
t.Fatal("expected number of events")
}
if !bytes.Equal(ev[0].DNSQuery, query) {
if !bytes.Equal(ev[0].DNSQuery, rawQuery) {
t.Fatal("unexpected DNSQuery")
}
if ev[0].Name != "dns_round_trip_start" {
@@ -136,7 +151,7 @@ func TestSaverDNSTransportFailure(t *testing.T) {
if !ev[0].Time.Before(time.Now()) {
t.Fatal("the saved time is wrong")
}
if !bytes.Equal(ev[1].DNSQuery, query) {
if !bytes.Equal(ev[1].DNSQuery, rawQuery) {
t.Fatal("unexpected DNSQuery")
}
if ev[1].DNSReply != nil {
@@ -157,27 +172,45 @@ func TestSaverDNSTransportFailure(t *testing.T) {
}
func TestSaverDNSTransportSuccess(t *testing.T) {
expected := []byte("def")
expected := []byte{0xef, 0xbe, 0xad, 0xde}
saver := &trace.Saver{}
response := &mocks.DNSResponse{
MockBytes: func() []byte {
return expected
},
}
txp := resolver.SaverDNSTransport{
DNSTransport: resolver.FakeTransport{
Data: expected,
DNSTransport: &mocks.DNSTransport{
MockRoundTrip: func(ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
return response, nil
},
MockNetwork: func() string {
return "fake"
},
MockAddress: func() string {
return ""
},
},
Saver: saver,
}
query := []byte("abc")
rawQuery := []byte{0xde, 0xad, 0xbe, 0xef}
query := &mocks.DNSQuery{
MockBytes: func() ([]byte, error) {
return rawQuery, nil
},
}
reply, err := txp.RoundTrip(context.Background(), query)
if err != nil {
t.Fatal("we expected nil error here")
}
if !bytes.Equal(reply, expected) {
if !bytes.Equal(reply.Bytes(), expected) {
t.Fatal("expected another reply here")
}
ev := saver.Read()
if len(ev) != 2 {
t.Fatal("expected number of events")
}
if !bytes.Equal(ev[0].DNSQuery, query) {
if !bytes.Equal(ev[0].DNSQuery, rawQuery) {
t.Fatal("unexpected DNSQuery")
}
if ev[0].Name != "dns_round_trip_start" {
@@ -186,7 +219,7 @@ func TestSaverDNSTransportSuccess(t *testing.T) {
if !ev[0].Time.Before(time.Now()) {
t.Fatal("the saved time is wrong")
}
if !bytes.Equal(ev[1].DNSQuery, query) {
if !bytes.Equal(ev[1].DNSQuery, rawQuery) {
t.Fatal("unexpected DNSQuery")
}
if !bytes.Equal(ev[1].DNSReply, expected) {