feat(netxlite): implement parallel resolver (#724)
This diff imports the parallel resolver from websteps winter 2022
edition, which was originally implemented here:
55231d73cd
See https://github.com/ooni/probe/issues/2096
This commit is contained in:
Simone Basso
GitHub
parent
0efd4ff130
commit
ec0561ea8c
131
internal/netxlite/parallelresolver.go
Normal file
131
internal/netxlite/parallelresolver.go
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@ -0,0 +1,131 @@
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package netxlite
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//
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// Parallel resolver implementation
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//
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import (
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"context"
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"github.com/miekg/dns"
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"github.com/ooni/probe-cli/v3/internal/atomicx"
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"github.com/ooni/probe-cli/v3/internal/model"
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)
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// ParallelResolver uses a transport and performs a LookupHost
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// operation in a parallel fashion, hence its name.
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//
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// You should probably use NewUnwrappedParallelResolver to
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// create a new instance of this type.
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type ParallelResolver struct {
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// Encoder is the MANDATORY encoder to use.
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Encoder model.DNSEncoder
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// Decoder is the MANDATORY decoder to use.
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Decoder model.DNSDecoder
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// NumTimeouts is MANDATORY and counts the number of timeouts.
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NumTimeouts *atomicx.Int64
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// Txp is the MANDATORY underlying DNS transport.
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Txp model.DNSTransport
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}
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// UnwrappedParallelResolver creates a new ParallelResolver instance. This instance is
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// not wrapped and you should wrap if before using it.
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func NewUnwrappedParallelResolver(t model.DNSTransport) *ParallelResolver {
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return &ParallelResolver{
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Encoder: &DNSEncoderMiekg{},
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Decoder: &DNSDecoderMiekg{},
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NumTimeouts: &atomicx.Int64{},
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Txp: t,
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}
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}
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// Transport returns the transport being used.
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func (r *ParallelResolver) Transport() model.DNSTransport {
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return r.Txp
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}
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// Network returns the "network" of the underlying transport.
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func (r *ParallelResolver) Network() string {
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return r.Txp.Network()
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}
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// Address returns the "address" of the underlying transport.
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func (r *ParallelResolver) Address() string {
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return r.Txp.Address()
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}
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// CloseIdleConnections closes idle connections, if any.
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func (r *ParallelResolver) CloseIdleConnections() {
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r.Txp.CloseIdleConnections()
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}
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// LookupHost performs an A lookup in parallel with an AAAA lookup.
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func (r *ParallelResolver) LookupHost(ctx context.Context, hostname string) ([]string, error) {
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ach := make(chan *parallelResolverResult)
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go r.lookupHost(ctx, hostname, dns.TypeA, ach)
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aaaach := make(chan *parallelResolverResult)
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go r.lookupHost(ctx, hostname, dns.TypeAAAA, aaaach)
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ares := <-ach
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aaaares := <-aaaach
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if ares.err != nil && aaaares.err != nil {
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// Note: we choose to return the A error because we assume that
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// it's the more meaningful one: the AAAA error may just be telling
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// us that there is no AAAA record for the website.
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return nil, ares.err
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}
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var addrs []string
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addrs = append(addrs, ares.addrs...)
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addrs = append(addrs, aaaares.addrs...)
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return addrs, nil
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}
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// LookupHTTPS implements Resolver.LookupHTTPS.
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func (r *ParallelResolver) LookupHTTPS(
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ctx context.Context, hostname string) (*model.HTTPSSvc, error) {
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querydata, err := r.Encoder.Encode(
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hostname, dns.TypeHTTPS, r.Txp.RequiresPadding())
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if err != nil {
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return nil, err
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}
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replydata, err := r.Txp.RoundTrip(ctx, querydata)
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if err != nil {
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return nil, err
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}
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return r.Decoder.DecodeHTTPS(replydata)
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}
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// parallelResolverResult is the internal representation of a
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// lookup using either the A or the AAAA query type.
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type parallelResolverResult struct {
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addrs []string
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err error
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}
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// lookupHost issues a lookup host query for the specified qtype (e.g., dns.A).
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func (r *ParallelResolver) lookupHost(ctx context.Context, hostname string,
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qtype uint16, out chan<- *parallelResolverResult) {
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querydata, err := r.Encoder.Encode(hostname, qtype, r.Txp.RequiresPadding())
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if err != nil {
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out <- ¶llelResolverResult{
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addrs: []string{},
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err: err,
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}
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return
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}
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replydata, err := r.Txp.RoundTrip(ctx, querydata)
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if err != nil {
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out <- ¶llelResolverResult{
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addrs: []string{},
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err: err,
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}
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return
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}
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addrs, err := r.Decoder.DecodeLookupHost(qtype, replydata)
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out <- ¶llelResolverResult{
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addrs: addrs,
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err: err,
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}
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}
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269
internal/netxlite/parallelresolver_test.go
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269
internal/netxlite/parallelresolver_test.go
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@ -0,0 +1,269 @@
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package netxlite
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import (
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"context"
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"crypto/tls"
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"errors"
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"testing"
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"github.com/miekg/dns"
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"github.com/ooni/probe-cli/v3/internal/atomicx"
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"github.com/ooni/probe-cli/v3/internal/model"
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"github.com/ooni/probe-cli/v3/internal/model/mocks"
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)
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func TestParallelResolver(t *testing.T) {
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t.Run("transport okay", func(t *testing.T) {
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txp := NewDNSOverTLS((&tls.Dialer{}).DialContext, "8.8.8.8:853")
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r := NewUnwrappedParallelResolver(txp)
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rtx := r.Transport()
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if rtx.Network() != "dot" || rtx.Address() != "8.8.8.8:853" {
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t.Fatal("not the transport we expected")
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}
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if r.Network() != rtx.Network() {
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t.Fatal("invalid network seen from the resolver")
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}
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if r.Address() != rtx.Address() {
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t.Fatal("invalid address seen from the resolver")
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}
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})
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t.Run("LookupHost", func(t *testing.T) {
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t.Run("Encode error", func(t *testing.T) {
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mocked := errors.New("mocked error")
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txp := NewDNSOverTLS((&tls.Dialer{}).DialContext, "8.8.8.8:853")
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r := ParallelResolver{
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Encoder: &mocks.DNSEncoder{
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MockEncode: func(domain string, qtype uint16, padding bool) ([]byte, error) {
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return nil, mocked
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},
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},
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Txp: txp,
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}
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if !errors.Is(err, mocked) {
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t.Fatal("not the error we expected")
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}
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if addrs != nil {
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t.Fatal("expected nil address here")
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}
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})
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t.Run("RoundTrip error", func(t *testing.T) {
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mocked := errors.New("mocked error")
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txp := &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return nil, mocked
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},
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MockRequiresPadding: func() bool {
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return true
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},
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}
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r := NewUnwrappedParallelResolver(txp)
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if !errors.Is(err, mocked) {
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t.Fatal("not the error we expected")
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}
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if addrs != nil {
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t.Fatal("expected nil address here")
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}
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})
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t.Run("empty reply", func(t *testing.T) {
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txp := &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return dnsGenLookupHostReplySuccess(t, dns.TypeA), nil
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},
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MockRequiresPadding: func() bool {
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return true
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},
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}
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r := NewUnwrappedParallelResolver(txp)
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if !errors.Is(err, ErrOODNSNoAnswer) {
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t.Fatal("not the error we expected", err)
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}
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if addrs != nil {
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t.Fatal("expected nil address here")
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}
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})
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t.Run("with A reply", func(t *testing.T) {
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txp := &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return dnsGenLookupHostReplySuccess(t, dns.TypeA, "8.8.8.8"), nil
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},
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MockRequiresPadding: func() bool {
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return true
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},
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}
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r := NewUnwrappedParallelResolver(txp)
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if err != nil {
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t.Fatal(err)
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}
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if len(addrs) != 1 || addrs[0] != "8.8.8.8" {
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t.Fatal("not the result we expected")
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}
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})
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t.Run("with AAAA reply", func(t *testing.T) {
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txp := &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return dnsGenLookupHostReplySuccess(t, dns.TypeAAAA, "::1"), nil
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},
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MockRequiresPadding: func() bool {
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return true
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},
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}
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r := NewUnwrappedParallelResolver(txp)
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if err != nil {
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t.Fatal(err)
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}
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if len(addrs) != 1 || addrs[0] != "::1" {
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t.Fatal("not the result we expected")
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}
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})
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t.Run("A failure takes precedence over AAAA failure", func(t *testing.T) {
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afailure := errors.New("a failure")
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aaaafailure := errors.New("aaaa failure")
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txp := &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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msg := &dns.Msg{}
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if err := msg.Unpack(query); err != nil {
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return nil, err
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}
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if len(msg.Question) != 1 {
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return nil, errors.New("expected just one question")
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}
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q := msg.Question[0]
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if q.Qtype == dns.TypeA {
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return nil, afailure
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}
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if q.Qtype == dns.TypeAAAA {
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return nil, aaaafailure
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}
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return nil, errors.New("expected A or AAAA query")
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},
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MockRequiresPadding: func() bool {
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return true
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},
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}
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r := NewUnwrappedParallelResolver(txp)
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addrs, err := r.LookupHost(context.Background(), "www.gogle.com")
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if !errors.Is(err, afailure) {
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t.Fatal("unexpected error", err)
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}
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if len(addrs) != 0 {
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t.Fatal("not the result we expected")
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}
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})
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})
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t.Run("CloseIdleConnections", func(t *testing.T) {
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var called bool
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r := &ParallelResolver{
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Txp: &mocks.DNSTransport{
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MockCloseIdleConnections: func() {
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called = true
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},
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},
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}
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r.CloseIdleConnections()
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if !called {
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t.Fatal("not called")
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}
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})
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t.Run("LookupHTTPS", func(t *testing.T) {
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t.Run("for encoding error", func(t *testing.T) {
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expected := errors.New("mocked error")
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r := &ParallelResolver{
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Encoder: &mocks.DNSEncoder{
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MockEncode: func(domain string, qtype uint16, padding bool) ([]byte, error) {
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return nil, expected
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},
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},
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Decoder: nil,
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NumTimeouts: &atomicx.Int64{},
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Txp: &mocks.DNSTransport{
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MockRequiresPadding: func() bool {
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return false
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},
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},
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}
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ctx := context.Background()
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https, err := r.LookupHTTPS(ctx, "example.com")
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if !errors.Is(err, expected) {
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t.Fatal("unexpected err", err)
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}
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if https != nil {
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t.Fatal("unexpected result")
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}
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})
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t.Run("for round-trip error", func(t *testing.T) {
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expected := errors.New("mocked error")
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r := &ParallelResolver{
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Encoder: &mocks.DNSEncoder{
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MockEncode: func(domain string, qtype uint16, padding bool) ([]byte, error) {
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return make([]byte, 64), nil
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},
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},
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Decoder: nil,
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NumTimeouts: &atomicx.Int64{},
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Txp: &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return nil, expected
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},
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MockRequiresPadding: func() bool {
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return false
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},
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},
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}
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ctx := context.Background()
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https, err := r.LookupHTTPS(ctx, "example.com")
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if !errors.Is(err, expected) {
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t.Fatal("unexpected err", err)
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}
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if https != nil {
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t.Fatal("unexpected result")
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}
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})
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t.Run("for decode error", func(t *testing.T) {
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expected := errors.New("mocked error")
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r := &ParallelResolver{
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Encoder: &mocks.DNSEncoder{
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MockEncode: func(domain string, qtype uint16, padding bool) ([]byte, error) {
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return make([]byte, 64), nil
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},
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},
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Decoder: &mocks.DNSDecoder{
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MockDecodeHTTPS: func(reply []byte) (*model.HTTPSSvc, error) {
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return nil, expected
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},
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},
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NumTimeouts: &atomicx.Int64{},
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Txp: &mocks.DNSTransport{
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MockRoundTrip: func(ctx context.Context, query []byte) (reply []byte, err error) {
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return make([]byte, 128), nil
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},
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MockRequiresPadding: func() bool {
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return false
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},
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},
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}
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ctx := context.Background()
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https, err := r.LookupHTTPS(ctx, "example.com")
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if !errors.Is(err, expected) {
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t.Fatal("unexpected err", err)
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}
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if https != nil {
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t.Fatal("unexpected result")
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}
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})
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})
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}
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@ -1,5 +1,9 @@
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package netxlite
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//
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// Serial resolver implementation
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//
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import (
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"context"
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"errors"
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@ -10,11 +14,13 @@ import (
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"github.com/ooni/probe-cli/v3/internal/model"
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)
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// SerialResolver uses a transport and sends performs a LookupHost
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// SerialResolver uses a transport and performs a LookupHost
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// operation in a serial fashion (query for A first, wait for response,
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// then query for AAAA, and wait for response), hence its name.
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//
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// You should probably use NewSerialResolver to create a new instance.
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//
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// Deprecated: please use ParallelResolver in new code.
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type SerialResolver struct {
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// Encoder is the MANDATORY encoder to use.
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Encoder model.DNSEncoder
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@ -25,7 +31,7 @@ type SerialResolver struct {
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// NumTimeouts is MANDATORY and counts the number of timeouts.
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NumTimeouts *atomicx.Int64
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// Txp is the underlying DNS transport.
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// Txp is the MANDATORY underlying DNS transport.
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Txp model.DNSTransport
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}
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