Pull request: 2704 local addresses vol.4

Updates #2704.

Squashed commit of the following:

commit bbc292a1c9dc7382e1116cfd85fea22ab8de6949
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Apr 9 19:22:46 2021 +0300

    all: replace exchanger with proxy

internal/aghnet/exchanger.go

@@ -1,86 +0,0 @@
-package aghnet
-
-import (
-	"time"
-
-	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
-	"github.com/AdguardTeam/dnsproxy/upstream"
-	"github.com/miekg/dns"
-)
-
-// This package is not the best place for this functionality, but we put it here
-// since we need to use it in both rDNS (home) and dnsServer (dnsforward).
-
-// NoUpstreamsErr should be returned when there are no upstreams inside
-// Exchanger implementation.
-const NoUpstreamsErr agherr.Error = "no upstreams specified"
-
-// Exchanger represents an object able to resolve DNS messages.
-//
-// TODO(e.burkov): Maybe expand with method like ExchangeParallel to be able to
-// use user's upstream mode settings.  Also, think about Update method to
-// refresh the internal state.
-type Exchanger interface {
-	Exchange(req *dns.Msg) (resp *dns.Msg, err error)
-}
-
-// multiAddrExchanger is the default implementation of Exchanger interface.
-type multiAddrExchanger struct {
-	ups []upstream.Upstream
-}
-
-// NewMultiAddrExchanger creates an Exchanger instance from passed addresses.
-// It returns an error if any of addrs failed to become an upstream.
-func NewMultiAddrExchanger(
-	addrs []string,
-	bootstraps []string,
-	timeout time.Duration,
-) (e Exchanger, err error) {
-	defer agherr.Annotate("exchanger: %w", &err)
-
-	if len(addrs) == 0 {
-		return &multiAddrExchanger{}, nil
-	}
-
-	var ups []upstream.Upstream = make([]upstream.Upstream, 0, len(addrs))
-	for _, addr := range addrs {
-		var u upstream.Upstream
-		u, err = upstream.AddressToUpstream(addr, upstream.Options{
-			Bootstrap: bootstraps,
-			Timeout:   timeout,
-		})
-		if err != nil {
-			return nil, err
-		}
-
-		ups = append(ups, u)
-	}
-
-	return &multiAddrExchanger{ups: ups}, nil
-}
-
-// Exсhange performs a query to each resolver until first response.
-func (e *multiAddrExchanger) Exchange(req *dns.Msg) (resp *dns.Msg, err error) {
-	defer agherr.Annotate("exchanger: %w", &err)
-
-	// TODO(e.burkov): Maybe prohibit the initialization without upstreams.
-	if len(e.ups) == 0 {
-		return nil, NoUpstreamsErr
-	}
-
-	var errs []error
-	for _, u := range e.ups {
-		resp, err = u.Exchange(req)
-		if err != nil {
-			errs = append(errs, err)
-
-			continue
-		}
-
-		if resp != nil {
-			return resp, nil
-		}
-	}
-
-	return nil, agherr.Many("can't exchange", errs...)
-}

internal/aghnet/exchanger_test.go

@@ -1,64 +0,0 @@
-package aghnet
-
-import (
-	"testing"
-
-	"github.com/AdguardTeam/AdGuardHome/internal/aghtest"
-	"github.com/AdguardTeam/dnsproxy/upstream"
-	"github.com/miekg/dns"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestNewMultiAddrExchanger(t *testing.T) {
-	var e Exchanger
-	var err error
-
-	t.Run("empty", func(t *testing.T) {
-		e, err = NewMultiAddrExchanger([]string{}, nil, 0)
-		require.NoError(t, err)
-		assert.NotNil(t, e)
-	})
-
-	t.Run("successful", func(t *testing.T) {
-		e, err = NewMultiAddrExchanger([]string{"www.example.com"}, nil, 0)
-		require.NoError(t, err)
-		assert.NotNil(t, e)
-	})
-
-	t.Run("unsuccessful", func(t *testing.T) {
-		e, err = NewMultiAddrExchanger([]string{"invalid-proto://www.example.com"}, nil, 0)
-		require.Error(t, err)
-		assert.Nil(t, e)
-	})
-}
-
-func TestMultiAddrExchanger_Exchange(t *testing.T) {
-	e := &multiAddrExchanger{}
-
-	t.Run("error", func(t *testing.T) {
-		e.ups = []upstream.Upstream{&aghtest.TestErrUpstream{}}
-
-		resp, err := e.Exchange(nil)
-		require.Error(t, err)
-		assert.Nil(t, resp)
-	})
-
-	t.Run("success", func(t *testing.T) {
-		e.ups = []upstream.Upstream{&aghtest.TestUpstream{
-			Reverse: map[string][]string{
-				"abc": {"cba"},
-			},
-		}}
-
-		resp, err := e.Exchange(&dns.Msg{
-			Question: []dns.Question{{
-				Name:  "abc",
-				Qtype: dns.TypePTR,
-			}},
-		})
-		require.NoError(t, err)
-		require.Len(t, resp.Answer, 1)
-		assert.Equal(t, "cba", resp.Answer[0].Header().Name)
-	})
-}