Pull request: dnsforward: add dnsrewrite tests

Merge in DNS/adguard-home from 2102-dnsrewrite-tests to master

Updates #2102.

Squashed commit of the following:

commit 894ff4baf8378d6e3386e09c416d55241a01f79e
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Jan 14 14:49:28 2021 +0300

    dnsforward: add dnsrewrite tests

internal/dnsfilter/dnsrewrite.go

@@ -33,7 +33,7 @@ func (d *DNSFilter) processDNSRewrites(dnsr []*rules.NetworkRule) (res Result) {
 		if dr.NewCNAME != "" {
 			// NewCNAME rules have a higher priority than
 			// the other rules.
-			rules := []*ResultRule{{
+			rules = []*ResultRule{{
 				FilterListID: int64(nr.GetFilterListID()),
 				Text:         nr.RuleText,
 			}}
@@ -56,7 +56,7 @@ func (d *DNSFilter) processDNSRewrites(dnsr []*rules.NetworkRule) (res Result) {
 		default:
 			// RcodeRefused and other such codes have higher
 			// priority.  Return immediately.
-			rules := []*ResultRule{{
+			rules = []*ResultRule{{
 				FilterListID: int64(nr.GetFilterListID()),
 				Text:         nr.RuleText,
 			}}

internal/dnsfilter/safebrowsing.go

@@ -46,12 +46,12 @@ func (d *DNSFilter) initSecurityServices() error {
 
 	d.parentalUpstream, err = upstream.AddressToUpstream(d.parentalServer, opts)
 	if err != nil {
-		return err
+		return fmt.Errorf("converting parental server: %w", err)
 	}
 
 	d.safeBrowsingUpstream, err = upstream.AddressToUpstream(d.safeBrowsingServer, opts)
 	if err != nil {
-		return err
+		return fmt.Errorf("converting safe browsing server: %w", err)
 	}
 
 	return nil

internal/dnsforward/dnsrewrite_test.go

@@ -0,0 +1,172 @@
+package dnsforward
+
+import (
+	"net"
+	"testing"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
+	"github.com/AdguardTeam/dnsproxy/proxy"
+	"github.com/AdguardTeam/urlfilter/rules"
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestServer_FilterDNSRewrite(t *testing.T) {
+	// Helper data.
+	ip4 := net.IP{127, 0, 0, 1}
+	ip6 := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	mx := &rules.DNSMX{
+		Exchange:   "mail.example.com",
+		Preference: 32,
+	}
+	svcb := &rules.DNSSVCB{
+		Params:   map[string]string{"alpn": "h3"},
+		Target:   "example.com",
+		Priority: 32,
+	}
+	const domain = "example.com"
+
+	// Helper functions and entities.
+	srv := &Server{}
+	makeQ := func(qtype rules.RRType) (req *dns.Msg) {
+		return &dns.Msg{
+			Question: []dns.Question{{
+				Qtype: qtype,
+			}},
+		}
+	}
+	makeRes := func(rcode rules.RCode, rr rules.RRType, v rules.RRValue) (res dnsfilter.Result) {
+		resp := dnsfilter.DNSRewriteResultResponse{
+			rr: []rules.RRValue{v},
+		}
+		return dnsfilter.Result{
+			DNSRewriteResult: &dnsfilter.DNSRewriteResult{
+				RCode:    rcode,
+				Response: resp,
+			},
+		}
+	}
+
+	// Tests.
+	t.Run("nxdomain", func(t *testing.T) {
+		req := makeQ(dns.TypeA)
+		res := makeRes(dns.RcodeNameError, 0, nil)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeNameError, d.Res.Rcode)
+	})
+
+	t.Run("noerror_empty", func(t *testing.T) {
+		req := makeQ(dns.TypeA)
+		res := makeRes(dns.RcodeSuccess, 0, nil)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		assert.Empty(t, d.Res.Answer)
+	})
+
+	t.Run("noerror_a", func(t *testing.T) {
+		req := makeQ(dns.TypeA)
+		res := makeRes(dns.RcodeSuccess, dns.TypeA, ip4)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			assert.Equal(t, ip4, d.Res.Answer[0].(*dns.A).A)
+		}
+	})
+
+	t.Run("noerror_aaaa", func(t *testing.T) {
+		req := makeQ(dns.TypeAAAA)
+		res := makeRes(dns.RcodeSuccess, dns.TypeAAAA, ip6)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			assert.Equal(t, ip6, d.Res.Answer[0].(*dns.AAAA).AAAA)
+		}
+	})
+
+	t.Run("noerror_ptr", func(t *testing.T) {
+		req := makeQ(dns.TypePTR)
+		res := makeRes(dns.RcodeSuccess, dns.TypePTR, domain)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			assert.Equal(t, domain, d.Res.Answer[0].(*dns.PTR).Ptr)
+		}
+	})
+
+	t.Run("noerror_txt", func(t *testing.T) {
+		req := makeQ(dns.TypeTXT)
+		res := makeRes(dns.RcodeSuccess, dns.TypeTXT, domain)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			assert.Equal(t, []string{domain}, d.Res.Answer[0].(*dns.TXT).Txt)
+		}
+	})
+
+	t.Run("noerror_mx", func(t *testing.T) {
+		req := makeQ(dns.TypeMX)
+		res := makeRes(dns.RcodeSuccess, dns.TypeMX, mx)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			ans := d.Res.Answer[0].(*dns.MX)
+			assert.Equal(t, mx.Exchange, ans.Mx)
+			assert.Equal(t, mx.Preference, ans.Preference)
+		}
+	})
+
+	t.Run("noerror_svcb", func(t *testing.T) {
+		req := makeQ(dns.TypeSVCB)
+		res := makeRes(dns.RcodeSuccess, dns.TypeSVCB, svcb)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			ans := d.Res.Answer[0].(*dns.SVCB)
+			assert.Equal(t, dns.SVCB_ALPN, ans.Value[0].Key())
+			assert.Equal(t, svcb.Params["alpn"], ans.Value[0].String())
+			assert.Equal(t, svcb.Target, ans.Target)
+			assert.Equal(t, svcb.Priority, ans.Priority)
+		}
+	})
+
+	t.Run("noerror_https", func(t *testing.T) {
+		req := makeQ(dns.TypeHTTPS)
+		res := makeRes(dns.RcodeSuccess, dns.TypeHTTPS, svcb)
+		d := &proxy.DNSContext{}
+
+		err := srv.filterDNSRewrite(req, res, d)
+		assert.Nil(t, err)
+		assert.Equal(t, dns.RcodeSuccess, d.Res.Rcode)
+		if assert.Len(t, d.Res.Answer, 1) {
+			ans := d.Res.Answer[0].(*dns.HTTPS)
+			assert.Equal(t, dns.SVCB_ALPN, ans.Value[0].Key())
+			assert.Equal(t, svcb.Params["alpn"], ans.Value[0].String())
+			assert.Equal(t, svcb.Target, ans.Target)
+			assert.Equal(t, svcb.Priority, ans.Priority)
+		}
+	})
+}