Pull request: all: add $dnsrewrite handling

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

Updates #2102.

Squashed commit of the following:

commit 8490fc18179d38c4b162ff9b257fea1f8535afbd
Merge: d9448ddca e7f7799b3
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 21 16:44:00 2020 +0300

    Merge branch 'master' into 2102-dnsrewrite

commit d9448ddca6d4ef3635d767e3e496e44c35d3fc6e
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Dec 21 15:44:54 2020 +0300

    querylog: support dnsrewrite rules

commit 40aa5d30acddf29fb90d249d8806941c6e1915a4
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 18 19:27:40 2020 +0300

    all: improve documentation

commit f776a0cd63b1640ba1e5210d9301e2a2801fd824
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 18 19:09:08 2020 +0300

    dnsfilter: prevent panics, improve docs

commit e14073b7500d9ed827a151c5b8fb863c980c10e8
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 4 15:51:02 2020 +0300

    all: add $dnsrewrite handling

.githooks/pre-commit

@@ -2,12 +2,12 @@
 
 set -e -f -u
 
-if [ "$(git diff --cached --name-only '*.js')" ]
+if [ "$(git diff --cached --name-only -- '*.js')" ]
 then
 	make js-lint js-test
 fi
 
-if [ "$(git diff --cached --name-only '*.go')" ]
+if [ "$(git diff --cached --name-only -- '*.go' 'go.mod')" ]
 then
 	make go-lint go-test
 fi

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to
 
 ### Added
 
+- `$dnsrewrite` modifier for filters ([#2102]).
 - The host checking API and the query logs API can now return multiple matched
   rules ([#2102]).
 - Detecting of network interface configured to have static IP address via

Makefile

@@ -35,6 +35,7 @@ GPG_KEY := devteam@adguard.com
 GPG_KEY_PASSPHRASE :=
 GPG_CMD := gpg --detach-sig --default-key $(GPG_KEY) --pinentry-mode loopback --passphrase $(GPG_KEY_PASSPHRASE)
 VERBOSE := -v
+REBUILD_CLIENT = 1
 
 # See release target
 DIST_DIR=dist
@@ -124,7 +125,8 @@ all: build
 init:
 	git config core.hooksPath .githooks
 
-build: client_with_deps
+build:
+	test '$(REBUILD_CLIENT)' = '1' && $(MAKE) client_with_deps || exit 0
 	$(GO) mod download
 	PATH=$(GOPATH)/bin:$(PATH) $(GO) generate ./...
 	CGO_ENABLED=0 $(GO) build -ldflags="-s -w -X main.version=$(VERSION) -X main.channel=$(CHANNEL) -X main.goarm=$(GOARM)"

README.md

@@ -255,7 +255,7 @@ curl -sSL https://raw.githubusercontent.com/AdguardTeam/AdGuardHome/master/scrip
 
 * Beta channel builds
     * Linux: [64-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_amd64.tar.gz), [32-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_386.tar.gz)
-    * Linux ARM: [32-bit ARMv6](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv6.tar.gz) (recommended for Rapsberry Pi), [64-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_arm64.tar.gz), [32-bit ARMv5](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv5.tar.gz), [32-bit ARMv7](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv7.tar.gz)
+    * Linux ARM: [32-bit ARMv6](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv6.tar.gz) (recommended for Raspberry Pi), [64-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_arm64.tar.gz), [32-bit ARMv5](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv5.tar.gz), [32-bit ARMv7](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_armv7.tar.gz)
     * Linux MIPS: [32-bit MIPS](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_mips_softfloat.tar.gz), [32-bit MIPSLE](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_mipsle_softfloat.tar.gz), [64-bit MIPS](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_mips64_softfloat.tar.gz), [64-bit MIPSLE](https://static.adguard.com/adguardhome/beta/AdGuardHome_linux_mips64le_softfloat.tar.gz)
     * Windows: [64-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_windows_amd64.zip), [32-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_windows_386.zip)
     * MacOS: [64-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_darwin_amd64.zip), [32-bit](https://static.adguard.com/adguardhome/beta/AdGuardHome_darwin_386.zip)
@@ -264,7 +264,7 @@ curl -sSL https://raw.githubusercontent.com/AdguardTeam/AdGuardHome/master/scrip
 
 * Edge channel builds
     * Linux: [64-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_amd64.tar.gz), [32-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_386.tar.gz)
-    * Linux ARM: [32-bit ARMv6](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv6.tar.gz) (recommended for Rapsberry Pi), [64-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_arm64.tar.gz), [32-bit ARMv5](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv5.tar.gz), [32-bit ARMv7](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv7.tar.gz)
+    * Linux ARM: [32-bit ARMv6](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv6.tar.gz) (recommended for Raspberry Pi), [64-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_arm64.tar.gz), [32-bit ARMv5](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv5.tar.gz), [32-bit ARMv7](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_armv7.tar.gz)
     * Linux MIPS: [32-bit MIPS](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_mips_softfloat.tar.gz), [32-bit MIPSLE](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_mipsle_softfloat.tar.gz), [64-bit MIPS](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_mips64_softfloat.tar.gz), [64-bit MIPSLE](https://static.adguard.com/adguardhome/edge/AdGuardHome_linux_mips64le_softfloat.tar.gz)
     * Windows: [64-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_windows_amd64.zip), [32-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_windows_386.zip)
     * MacOS: [64-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_darwin_amd64.zip), [32-bit](https://static.adguard.com/adguardhome/edge/AdGuardHome_darwin_386.zip)

go.mod

@@ -5,7 +5,7 @@ go 1.14
 require (
 	github.com/AdguardTeam/dnsproxy v0.33.7
 	github.com/AdguardTeam/golibs v0.4.4
-	github.com/AdguardTeam/urlfilter v0.13.0
+	github.com/AdguardTeam/urlfilter v0.14.0
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/ameshkov/dnscrypt/v2 v2.0.1
 	github.com/fsnotify/fsnotify v1.4.9

go.sum

@@ -26,8 +26,8 @@ github.com/AdguardTeam/golibs v0.4.2/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKU
 github.com/AdguardTeam/golibs v0.4.4 h1:cM9UySQiYFW79zo5XRwnaIWVzfW4eNXmZktMrWbthpw=
 github.com/AdguardTeam/golibs v0.4.4/go.mod h1:skKsDKIBB7kkFflLJBpfGX+G8QFTx0WKUzB6TIgtUj4=
 github.com/AdguardTeam/gomitmproxy v0.2.0/go.mod h1:Qdv0Mktnzer5zpdpi5rAwixNJzW2FN91LjKJCkVbYGU=
-github.com/AdguardTeam/urlfilter v0.13.0 h1:MfO46K81JVTkhgP6gRu/buKl5wAOSfusjiDwjT1JN1c=
+github.com/AdguardTeam/urlfilter v0.14.0 h1:+aAhOvZDVGzl5gTERB4pOJCL1zxMyw7vLecJJ6TQTCw=
-github.com/AdguardTeam/urlfilter v0.13.0/go.mod h1:klx4JbOfc4EaNb5lWLqOwfg+pVcyRukmoJRvO55lL5U=
+github.com/AdguardTeam/urlfilter v0.14.0/go.mod h1:klx4JbOfc4EaNb5lWLqOwfg+pVcyRukmoJRvO55lL5U=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=

internal/dnsfilter/dnsfilter.go

@@ -1,4 +1,4 @@
-// Package dnsfilter implements a DNS filter.
+// Package dnsfilter implements a DNS request and response filter.
 package dnsfilter
 
 import (
@@ -95,8 +95,8 @@ type filtersInitializerParams struct {
 type DNSFilter struct {
 	rulesStorage         *filterlist.RuleStorage
 	filteringEngine      *urlfilter.DNSEngine
-	rulesStorageWhite    *filterlist.RuleStorage
+	rulesStorageAllow    *filterlist.RuleStorage
-	filteringEngineWhite *urlfilter.DNSEngine
+	filteringEngineAllow *urlfilter.DNSEngine
 	engineLock           sync.RWMutex
 
 	parentalServer       string // access via methods
@@ -127,16 +127,16 @@ const (
 
 	// NotFilteredNotFound - host was not find in any checks, default value for result
 	NotFilteredNotFound Reason = iota
-	// NotFilteredWhiteList - the host is explicitly whitelisted
+	// NotFilteredAllowList - the host is explicitly allowed
-	NotFilteredWhiteList
+	NotFilteredAllowList
 	// NotFilteredError is returned when there was an error during
 	// checking.  Reserved, currently unused.
 	NotFilteredError
 
 	// reasons for filtering
 
-	// FilteredBlackList - the host was matched to be advertising host
+	// FilteredBlockList - the host was matched to be advertising host
-	FilteredBlackList
+	FilteredBlockList
 	// FilteredSafeBrowsing - the host was matched to be malicious/phishing
 	FilteredSafeBrowsing
 	// FilteredParental - the host was matched to be outside of parental control settings
@@ -155,16 +155,20 @@ const (
 	// RewriteAutoHosts is returned when there was a rewrite by
 	// autohosts rules (/etc/hosts and so on).
 	RewriteAutoHosts
+
+	// DNSRewriteRule is returned when a $dnsrewrite filter rule was
+	// applied.
+	DNSRewriteRule
 )
 
 // TODO(a.garipov): Resync with actual code names or replace completely
 // in HTTP API v1.
 var reasonNames = []string{
 	NotFilteredNotFound:  "NotFilteredNotFound",
-	NotFilteredWhiteList: "NotFilteredWhiteList",
+	NotFilteredAllowList: "NotFilteredWhiteList",
 	NotFilteredError:     "NotFilteredError",
 
-	FilteredBlackList:      "FilteredBlackList",
+	FilteredBlockList:      "FilteredBlackList",
 	FilteredSafeBrowsing:   "FilteredSafeBrowsing",
 	FilteredParental:       "FilteredParental",
 	FilteredInvalid:        "FilteredInvalid",
@@ -174,12 +178,15 @@ var reasonNames = []string{
 	ReasonRewrite: "Rewrite",
 
 	RewriteAutoHosts: "RewriteEtcHosts",
+
+	DNSRewriteRule: "DNSRewriteRule",
 }
 
 func (r Reason) String() string {
-	if uint(r) >= uint(len(reasonNames)) {
+	if r < 0 || int(r) >= len(reasonNames) {
 		return ""
 	}
+
 	return reasonNames[r]
 }
 
@@ -278,16 +285,15 @@ func (d *DNSFilter) reset() {
 		}
 	}
 
-	if d.rulesStorageWhite != nil {
+	if d.rulesStorageAllow != nil {
-		err = d.rulesStorageWhite.Close()
+		err = d.rulesStorageAllow.Close()
 		if err != nil {
-			log.Error("dnsfilter: rulesStorageWhite.Close: %s", err)
+			log.Error("dnsfilter: rulesStorageAllow.Close: %s", err)
 		}
 	}
 }
 
 type dnsFilterContext struct {
-	stats             Stats
 	safebrowsingCache cache.Cache
 	parentalCache     cache.Cache
 	safeSearchCache   cache.Cache
@@ -339,6 +345,9 @@ type Result struct {
 	// ServiceName is the name of the blocked service.  It is empty
 	// unless Reason is set to FilteredBlockedService.
 	ServiceName string `json:",omitempty"`
+
+	// DNSRewriteResult is the $dnsrewrite filter rule result.
+	DNSRewriteResult *DNSRewriteResult `json:",omitempty"`
 }
 
 // Matched returns true if any match at all was found regardless of
@@ -383,9 +392,6 @@ func (d *DNSFilter) CheckHost(host string, qtype uint16, setts *RequestFiltering
 		}
 	}
 
-	// Then check the filter lists.
-	// if request is blocked -- it should be blocked.
-	// if it is whitelisted -- we should do nothing with it anymore.
 	if setts.FilteringEnabled {
 		result, err = d.matchHost(host, qtype, *setts)
 		if err != nil {
@@ -476,9 +482,7 @@ func (d *DNSFilter) checkAutoHosts(host string, qtype uint16, result *Result) (m
 //  . repeat for the new domain name (Note: we return only the last CNAME)
 // . Find A or AAAA record for a domain name (exact match or by wildcard)
 //  . if found, set IP addresses (IPv4 or IPv6 depending on qtype) in Result.IPList array
-func (d *DNSFilter) processRewrites(host string, qtype uint16) Result {
+func (d *DNSFilter) processRewrites(host string, qtype uint16) (res Result) {
-	var res Result
-
 	d.confLock.RLock()
 	defer d.confLock.RUnlock()
 
@@ -493,7 +497,8 @@ func (d *DNSFilter) processRewrites(host string, qtype uint16) Result {
 		log.Debug("Rewrite: CNAME for %s is %s", host, rr[0].Answer)
 
 		if host == rr[0].Answer { // "host == CNAME" is an exception
-			res.Reason = 0
+			res.Reason = NotFilteredNotFound
+
 			return res
 		}
 
@@ -616,7 +621,7 @@ func (d *DNSFilter) initFiltering(allowFilters, blockFilters []Filter) error {
 	if err != nil {
 		return err
 	}
-	rulesStorageWhite, filteringEngineWhite, err := createFilteringEngine(allowFilters)
+	rulesStorageAllow, filteringEngineAllow, err := createFilteringEngine(allowFilters)
 	if err != nil {
 		return err
 	}
@@ -625,8 +630,8 @@ func (d *DNSFilter) initFiltering(allowFilters, blockFilters []Filter) error {
 	d.reset()
 	d.rulesStorage = rulesStorage
 	d.filteringEngine = filteringEngine
-	d.rulesStorageWhite = rulesStorageWhite
+	d.rulesStorageAllow = rulesStorageAllow
-	d.filteringEngineWhite = filteringEngineWhite
+	d.filteringEngineAllow = filteringEngineAllow
 	d.engineLock.Unlock()
 
 	// Make sure that the OS reclaims memory as soon as possible
@@ -636,9 +641,31 @@ func (d *DNSFilter) initFiltering(allowFilters, blockFilters []Filter) error {
 	return nil
 }
 
+// matchHostProcessAllowList processes the allowlist logic of host
+// matching.
+func (d *DNSFilter) matchHostProcessAllowList(host string, dnsres urlfilter.DNSResult) (res Result, err error) {
+	var rule rules.Rule
+	if dnsres.NetworkRule != nil {
+		rule = dnsres.NetworkRule
+	} else if len(dnsres.HostRulesV4) > 0 {
+		rule = dnsres.HostRulesV4[0]
+	} else if len(dnsres.HostRulesV6) > 0 {
+		rule = dnsres.HostRulesV6[0]
+	}
+
+	if rule == nil {
+		return Result{}, fmt.Errorf("invalid dns result: rules are empty")
+	}
+
+	log.Debug("Filtering: found allowlist rule for host %q: %q  list_id: %d",
+		host, rule.Text(), rule.GetFilterListID())
+
+	return makeResult(rule, NotFilteredAllowList), nil
+}
+
 // matchHost is a low-level way to check only if hostname is filtered by rules,
 // skipping expensive safebrowsing and parental lookups.
-func (d *DNSFilter) matchHost(host string, qtype uint16, setts RequestFilteringSettings) (Result, error) {
+func (d *DNSFilter) matchHost(host string, qtype uint16, setts RequestFilteringSettings) (res Result, err error) {
 	d.engineLock.RLock()
 	// Keep in mind that this lock must be held no just when calling Match()
 	//  but also while using the rules returned by it.
@@ -652,22 +679,10 @@ func (d *DNSFilter) matchHost(host string, qtype uint16, setts RequestFilteringS
 		DNSType:          qtype,
 	}
 
-	if d.filteringEngineWhite != nil {
+	if d.filteringEngineAllow != nil {
-		rr, ok := d.filteringEngineWhite.MatchRequest(ureq)
+		dnsres, ok := d.filteringEngineAllow.MatchRequest(ureq)
 		if ok {
-			var rule rules.Rule
+			return d.matchHostProcessAllowList(host, dnsres)
-			if rr.NetworkRule != nil {
-				rule = rr.NetworkRule
-			} else if rr.HostRulesV4 != nil {
-				rule = rr.HostRulesV4[0]
-			} else if rr.HostRulesV6 != nil {
-				rule = rr.HostRulesV6[0]
-			}
-
-			log.Debug("Filtering: found whitelist rule for host %q: %q  list_id: %d",
-				host, rule.Text(), rule.GetFilterListID())
-			res := makeResult(rule, NotFilteredWhiteList)
-			return res, nil
 		}
 	}
 
@@ -675,54 +690,65 @@ func (d *DNSFilter) matchHost(host string, qtype uint16, setts RequestFilteringS
 		return Result{}, nil
 	}
 
-	rr, ok := d.filteringEngine.MatchRequest(ureq)
+	dnsres, ok := d.filteringEngine.MatchRequest(ureq)
-	if !ok {
+
+	// Check DNS rewrites first, because the API there is a bit
+	// awkward.
+	if dnsr := dnsres.DNSRewrites(); len(dnsr) > 0 {
+		res = d.processDNSRewrites(dnsr)
+		if res.Reason == DNSRewriteRule && res.CanonName == host {
+			// A rewrite of a host to itself.  Go on and
+			// try matching other things.
+		} else {
+			return res, nil
+		}
+	} else if !ok {
 		return Result{}, nil
 	}
 
-	if rr.NetworkRule != nil {
+	if dnsres.NetworkRule != nil {
 		log.Debug("Filtering: found rule for host %q: %q  list_id: %d",
-			host, rr.NetworkRule.Text(), rr.NetworkRule.GetFilterListID())
+			host, dnsres.NetworkRule.Text(), dnsres.NetworkRule.GetFilterListID())
-		reason := FilteredBlackList
+		reason := FilteredBlockList
-		if rr.NetworkRule.Whitelist {
+		if dnsres.NetworkRule.Whitelist {
-			reason = NotFilteredWhiteList
+			reason = NotFilteredAllowList
-		}
-		res := makeResult(rr.NetworkRule, reason)
-		return res, nil
 		}
 
-	if qtype == dns.TypeA && rr.HostRulesV4 != nil {
+		return makeResult(dnsres.NetworkRule, reason), nil
-		rule := rr.HostRulesV4[0] // note that we process only 1 matched rule
+	}
+
+	if qtype == dns.TypeA && dnsres.HostRulesV4 != nil {
+		rule := dnsres.HostRulesV4[0] // note that we process only 1 matched rule
 		log.Debug("Filtering: found rule for host %q: %q  list_id: %d",
 			host, rule.Text(), rule.GetFilterListID())
-		res := makeResult(rule, FilteredBlackList)
+		res = makeResult(rule, FilteredBlockList)
 		res.Rules[0].IP = rule.IP.To4()
 
 		return res, nil
 	}
 
-	if qtype == dns.TypeAAAA && rr.HostRulesV6 != nil {
+	if qtype == dns.TypeAAAA && dnsres.HostRulesV6 != nil {
-		rule := rr.HostRulesV6[0] // note that we process only 1 matched rule
+		rule := dnsres.HostRulesV6[0] // note that we process only 1 matched rule
 		log.Debug("Filtering: found rule for host %q: %q  list_id: %d",
 			host, rule.Text(), rule.GetFilterListID())
-		res := makeResult(rule, FilteredBlackList)
+		res = makeResult(rule, FilteredBlockList)
 		res.Rules[0].IP = rule.IP
 
 		return res, nil
 	}
 
-	if rr.HostRulesV4 != nil || rr.HostRulesV6 != nil {
+	if dnsres.HostRulesV4 != nil || dnsres.HostRulesV6 != nil {
 		// Question Type doesn't match the host rules
 		// Return the first matched host rule, but without an IP address
 		var rule rules.Rule
-		if rr.HostRulesV4 != nil {
+		if dnsres.HostRulesV4 != nil {
-			rule = rr.HostRulesV4[0]
+			rule = dnsres.HostRulesV4[0]
-		} else if rr.HostRulesV6 != nil {
+		} else if dnsres.HostRulesV6 != nil {
-			rule = rr.HostRulesV6[0]
+			rule = dnsres.HostRulesV6[0]
 		}
 		log.Debug("Filtering: found rule for host %q: %q  list_id: %d",
 			host, rule.Text(), rule.GetFilterListID())
-		res := makeResult(rule, FilteredBlackList)
+		res = makeResult(rule, FilteredBlockList)
 		res.Rules[0].IP = net.IP{}
 
 		return res, nil
@@ -741,7 +767,7 @@ func makeResult(rule rules.Rule, reason Reason) Result {
 		}},
 	}
 
-	if reason == FilteredBlackList {
+	if reason == FilteredBlockList {
 		res.IsFiltered = true
 	}
 

internal/dnsfilter/dnsfilter_test.go

@@ -178,7 +178,6 @@ func TestSafeBrowsing(t *testing.T) {
 
 	d := NewForTest(&Config{SafeBrowsingEnabled: true}, nil)
 	defer d.Close()
-	gctx.stats.Safebrowsing.Requests = 0
 	d.checkMatch(t, "wmconvirus.narod.ru")
 
 	assert.True(t, strings.Contains(logOutput.String(), "SafeBrowsing lookup for wmconvirus.narod.ru"))
@@ -366,7 +365,7 @@ const nl = "\n"
 
 const (
 	blockingRules  = `||example.org^` + nl
-	whitelistRules = `||example.org^` + nl + `@@||test.example.org` + nl
+	allowlistRules = `||example.org^` + nl + `@@||test.example.org` + nl
 	importantRules = `@@||example.org^` + nl + `||test.example.org^$important` + nl
 	regexRules     = `/example\.org/` + nl + `@@||test.example.org^` + nl
 	maskRules      = `test*.example.org^` + nl + `exam*.com` + nl
@@ -381,49 +380,49 @@ var tests = []struct {
 	reason     Reason
 	dnsType    uint16
 }{
-	{"sanity", "||doubleclick.net^", "www.doubleclick.net", true, FilteredBlackList, dns.TypeA},
+	{"sanity", "||doubleclick.net^", "www.doubleclick.net", true, FilteredBlockList, dns.TypeA},
 	{"sanity", "||doubleclick.net^", "nodoubleclick.net", false, NotFilteredNotFound, dns.TypeA},
 	{"sanity", "||doubleclick.net^", "doubleclick.net.ru", false, NotFilteredNotFound, dns.TypeA},
 	{"sanity", "||doubleclick.net^", "wmconvirus.narod.ru", false, NotFilteredNotFound, dns.TypeA},
 
-	{"blocking", blockingRules, "example.org", true, FilteredBlackList, dns.TypeA},
+	{"blocking", blockingRules, "example.org", true, FilteredBlockList, dns.TypeA},
-	{"blocking", blockingRules, "test.example.org", true, FilteredBlackList, dns.TypeA},
+	{"blocking", blockingRules, "test.example.org", true, FilteredBlockList, dns.TypeA},
-	{"blocking", blockingRules, "test.test.example.org", true, FilteredBlackList, dns.TypeA},
+	{"blocking", blockingRules, "test.test.example.org", true, FilteredBlockList, dns.TypeA},
 	{"blocking", blockingRules, "testexample.org", false, NotFilteredNotFound, dns.TypeA},
 	{"blocking", blockingRules, "onemoreexample.org", false, NotFilteredNotFound, dns.TypeA},
 
-	{"whitelist", whitelistRules, "example.org", true, FilteredBlackList, dns.TypeA},
+	{"allowlist", allowlistRules, "example.org", true, FilteredBlockList, dns.TypeA},
-	{"whitelist", whitelistRules, "test.example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"allowlist", allowlistRules, "test.example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"whitelist", whitelistRules, "test.test.example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"allowlist", allowlistRules, "test.test.example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"whitelist", whitelistRules, "testexample.org", false, NotFilteredNotFound, dns.TypeA},
+	{"allowlist", allowlistRules, "testexample.org", false, NotFilteredNotFound, dns.TypeA},
-	{"whitelist", whitelistRules, "onemoreexample.org", false, NotFilteredNotFound, dns.TypeA},
+	{"allowlist", allowlistRules, "onemoreexample.org", false, NotFilteredNotFound, dns.TypeA},
 
-	{"important", importantRules, "example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"important", importantRules, "example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"important", importantRules, "test.example.org", true, FilteredBlackList, dns.TypeA},
+	{"important", importantRules, "test.example.org", true, FilteredBlockList, dns.TypeA},
-	{"important", importantRules, "test.test.example.org", true, FilteredBlackList, dns.TypeA},
+	{"important", importantRules, "test.test.example.org", true, FilteredBlockList, dns.TypeA},
 	{"important", importantRules, "testexample.org", false, NotFilteredNotFound, dns.TypeA},
 	{"important", importantRules, "onemoreexample.org", false, NotFilteredNotFound, dns.TypeA},
 
-	{"regex", regexRules, "example.org", true, FilteredBlackList, dns.TypeA},
+	{"regex", regexRules, "example.org", true, FilteredBlockList, dns.TypeA},
-	{"regex", regexRules, "test.example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"regex", regexRules, "test.example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"regex", regexRules, "test.test.example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"regex", regexRules, "test.test.example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"regex", regexRules, "testexample.org", true, FilteredBlackList, dns.TypeA},
+	{"regex", regexRules, "testexample.org", true, FilteredBlockList, dns.TypeA},
-	{"regex", regexRules, "onemoreexample.org", true, FilteredBlackList, dns.TypeA},
+	{"regex", regexRules, "onemoreexample.org", true, FilteredBlockList, dns.TypeA},
 
-	{"mask", maskRules, "test.example.org", true, FilteredBlackList, dns.TypeA},
+	{"mask", maskRules, "test.example.org", true, FilteredBlockList, dns.TypeA},
-	{"mask", maskRules, "test2.example.org", true, FilteredBlackList, dns.TypeA},
+	{"mask", maskRules, "test2.example.org", true, FilteredBlockList, dns.TypeA},
-	{"mask", maskRules, "example.com", true, FilteredBlackList, dns.TypeA},
+	{"mask", maskRules, "example.com", true, FilteredBlockList, dns.TypeA},
-	{"mask", maskRules, "exampleeee.com", true, FilteredBlackList, dns.TypeA},
+	{"mask", maskRules, "exampleeee.com", true, FilteredBlockList, dns.TypeA},
-	{"mask", maskRules, "onemoreexamsite.com", true, FilteredBlackList, dns.TypeA},
+	{"mask", maskRules, "onemoreexamsite.com", true, FilteredBlockList, dns.TypeA},
 	{"mask", maskRules, "example.org", false, NotFilteredNotFound, dns.TypeA},
 	{"mask", maskRules, "testexample.org", false, NotFilteredNotFound, dns.TypeA},
 	{"mask", maskRules, "example.co.uk", false, NotFilteredNotFound, dns.TypeA},
 
 	{"dnstype", dnstypeRules, "onemoreexample.org", false, NotFilteredNotFound, dns.TypeA},
 	{"dnstype", dnstypeRules, "example.org", false, NotFilteredNotFound, dns.TypeA},
-	{"dnstype", dnstypeRules, "example.org", true, FilteredBlackList, dns.TypeAAAA},
+	{"dnstype", dnstypeRules, "example.org", true, FilteredBlockList, dns.TypeAAAA},
-	{"dnstype", dnstypeRules, "test.example.org", false, NotFilteredWhiteList, dns.TypeA},
+	{"dnstype", dnstypeRules, "test.example.org", false, NotFilteredAllowList, dns.TypeA},
-	{"dnstype", dnstypeRules, "test.example.org", false, NotFilteredWhiteList, dns.TypeAAAA},
+	{"dnstype", dnstypeRules, "test.example.org", false, NotFilteredAllowList, dns.TypeAAAA},
 }
 
 func TestMatching(t *testing.T) {
@@ -470,7 +469,7 @@ func TestWhitelist(t *testing.T) {
 	// matched by white filter
 	res, err := d.CheckHost("host1", dns.TypeA, &setts)
 	assert.True(t, err == nil)
-	assert.True(t, !res.IsFiltered && res.Reason == NotFilteredWhiteList)
+	assert.True(t, !res.IsFiltered && res.Reason == NotFilteredAllowList)
 	if assert.Len(t, res.Rules, 1) {
 		assert.True(t, res.Rules[0].Text == "||host1^")
 	}
@@ -478,7 +477,7 @@ func TestWhitelist(t *testing.T) {
 	// not matched by white filter, but matched by block filter
 	res, err = d.CheckHost("host2", dns.TypeA, &setts)
 	assert.True(t, err == nil)
-	assert.True(t, res.IsFiltered && res.Reason == FilteredBlackList)
+	assert.True(t, res.IsFiltered && res.Reason == FilteredBlockList)
 	if assert.Len(t, res.Rules, 1) {
 		assert.True(t, res.Rules[0].Text == "||host2^")
 	}
@@ -512,8 +511,8 @@ func TestClientSettings(t *testing.T) {
 
 	// blocked by filters
 	r, _ = d.CheckHost("example.org", dns.TypeA, &setts)
-	if !r.IsFiltered || r.Reason != FilteredBlackList {
+	if !r.IsFiltered || r.Reason != FilteredBlockList {
-		t.Fatalf("CheckHost FilteredBlackList")
+		t.Fatalf("CheckHost FilteredBlockList")
 	}
 
 	// blocked by parental

internal/dnsfilter/dnsrewrite.go

@@ -0,0 +1,80 @@
+package dnsfilter
+
+import (
+	"github.com/AdguardTeam/urlfilter/rules"
+	"github.com/miekg/dns"
+)
+
+// DNSRewriteResult is the result of application of $dnsrewrite rules.
+type DNSRewriteResult struct {
+	RCode    rules.RCode              `json:",omitempty"`
+	Response DNSRewriteResultResponse `json:",omitempty"`
+}
+
+// DNSRewriteResultResponse is the collection of DNS response records
+// the server returns.
+type DNSRewriteResultResponse map[rules.RRType][]rules.RRValue
+
+// processDNSRewrites processes DNS rewrite rules in dnsr.  It returns
+// an empty result if dnsr is empty.  Otherwise, the result will have
+// either CanonName or DNSRewriteResult set.
+func (d *DNSFilter) processDNSRewrites(dnsr []*rules.NetworkRule) (res Result) {
+	if len(dnsr) == 0 {
+		return Result{}
+	}
+
+	var rules []*ResultRule
+	dnsrr := &DNSRewriteResult{
+		Response: DNSRewriteResultResponse{},
+	}
+
+	for _, nr := range dnsr {
+		dr := nr.DNSRewrite
+		if dr.NewCNAME != "" {
+			// NewCNAME rules have a higher priority than
+			// the other rules.
+			rules := []*ResultRule{{
+				FilterListID: int64(nr.GetFilterListID()),
+				Text:         nr.RuleText,
+			}}
+
+			return Result{
+				Reason:    DNSRewriteRule,
+				Rules:     rules,
+				CanonName: dr.NewCNAME,
+			}
+		}
+
+		switch dr.RCode {
+		case dns.RcodeSuccess:
+			dnsrr.RCode = dr.RCode
+			dnsrr.Response[dr.RRType] = append(dnsrr.Response[dr.RRType], dr.Value)
+			rules = append(rules, &ResultRule{
+				FilterListID: int64(nr.GetFilterListID()),
+				Text:         nr.RuleText,
+			})
+		default:
+			// RcodeRefused and other such codes have higher
+			// priority.  Return immediately.
+			rules := []*ResultRule{{
+				FilterListID: int64(nr.GetFilterListID()),
+				Text:         nr.RuleText,
+			}}
+			dnsrr = &DNSRewriteResult{
+				RCode: dr.RCode,
+			}
+
+			return Result{
+				Reason:           DNSRewriteRule,
+				Rules:            rules,
+				DNSRewriteResult: dnsrr,
+			}
+		}
+	}
+
+	return Result{
+		Reason:           DNSRewriteRule,
+		Rules:            rules,
+		DNSRewriteResult: dnsrr,
+	}
+}

internal/dnsfilter/dnsrewrite_test.go

@@ -0,0 +1,202 @@
+package dnsfilter
+
+import (
+	"net"
+	"path"
+	"testing"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDNSFilter_CheckHostRules_dnsrewrite(t *testing.T) {
+	const text = `
+|cname^$dnsrewrite=new_cname
+
+|a_record^$dnsrewrite=127.0.0.1
+
+|aaaa_record^$dnsrewrite=::1
+
+|txt_record^$dnsrewrite=NOERROR;TXT;hello_world
+
+|refused^$dnsrewrite=REFUSED
+
+|a_records^$dnsrewrite=127.0.0.1
+|a_records^$dnsrewrite=127.0.0.2
+
+|aaaa_records^$dnsrewrite=::1
+|aaaa_records^$dnsrewrite=::2
+
+|disable_one^$dnsrewrite=127.0.0.1
+|disable_one^$dnsrewrite=127.0.0.2
+@@||disable_one^$dnsrewrite=127.0.0.1
+
+|disable_cname^$dnsrewrite=127.0.0.1
+|disable_cname^$dnsrewrite=new_cname
+@@||disable_cname^$dnsrewrite=new_cname
+
+|disable_cname_many^$dnsrewrite=127.0.0.1
+|disable_cname_many^$dnsrewrite=new_cname_1
+|disable_cname_many^$dnsrewrite=new_cname_2
+@@||disable_cname_many^$dnsrewrite=new_cname_1
+
+|disable_all^$dnsrewrite=127.0.0.1
+|disable_all^$dnsrewrite=127.0.0.2
+@@||disable_all^$dnsrewrite
+`
+	f := NewForTest(nil, []Filter{{ID: 0, Data: []byte(text)}})
+	setts := &RequestFilteringSettings{
+		FilteringEnabled: true,
+	}
+
+	ipv4p1 := net.IPv4(127, 0, 0, 1)
+	ipv4p2 := net.IPv4(127, 0, 0, 2)
+	ipv6p1 := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	ipv6p2 := net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2}
+
+	t.Run("cname", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+		assert.Equal(t, "new_cname", res.CanonName)
+	})
+
+	t.Run("a_record", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 1) {
+				assert.Equal(t, ipv4p1, ipVals[0])
+			}
+		}
+	})
+
+	t.Run("aaaa_record", func(t *testing.T) {
+		dtyp := dns.TypeAAAA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 1) {
+				assert.Equal(t, ipv6p1, ipVals[0])
+			}
+		}
+	})
+
+	t.Run("txt_record", func(t *testing.T) {
+		dtyp := dns.TypeTXT
+		host := path.Base(t.Name())
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if strVals := dnsrr.Response[dtyp]; assert.Len(t, strVals, 1) {
+				assert.Equal(t, "hello_world", strVals[0])
+			}
+		}
+	})
+
+	t.Run("refused", func(t *testing.T) {
+		host := path.Base(t.Name())
+		res, err := f.CheckHostRules(host, dns.TypeA, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeRefused, dnsrr.RCode)
+		}
+	})
+
+	t.Run("a_records", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 2) {
+				assert.Equal(t, ipv4p1, ipVals[0])
+				assert.Equal(t, ipv4p2, ipVals[1])
+			}
+		}
+	})
+
+	t.Run("aaaa_records", func(t *testing.T) {
+		dtyp := dns.TypeAAAA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 2) {
+				assert.Equal(t, ipv6p1, ipVals[0])
+				assert.Equal(t, ipv6p2, ipVals[1])
+			}
+		}
+	})
+
+	t.Run("disable_one", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 1) {
+				assert.Equal(t, ipv4p2, ipVals[0])
+			}
+		}
+	})
+
+	t.Run("disable_cname", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+		assert.Equal(t, "", res.CanonName)
+
+		if dnsrr := res.DNSRewriteResult; assert.NotNil(t, dnsrr) {
+			assert.Equal(t, dns.RcodeSuccess, dnsrr.RCode)
+			if ipVals := dnsrr.Response[dtyp]; assert.Len(t, ipVals, 1) {
+				assert.Equal(t, ipv4p1, ipVals[0])
+			}
+		}
+	})
+
+	t.Run("disable_cname_many", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+		assert.Equal(t, "new_cname_2", res.CanonName)
+		assert.Nil(t, res.DNSRewriteResult)
+	})
+
+	t.Run("disable_all", func(t *testing.T) {
+		dtyp := dns.TypeA
+		host := path.Base(t.Name())
+
+		res, err := f.CheckHostRules(host, dtyp, setts)
+		assert.Nil(t, err)
+		assert.Equal(t, "", res.CanonName)
+		assert.Len(t, res.Rules, 0)
+	})
+}

internal/dnsforward/dns.go

@@ -366,7 +366,9 @@ func processFilteringAfterResponse(ctx *dnsContext) int {
 	var err error
 
 	switch res.Reason {
-	case dnsfilter.ReasonRewrite:
+	case dnsfilter.ReasonRewrite,
+		dnsfilter.DNSRewriteRule:
+
 		if len(ctx.origQuestion.Name) == 0 {
 			// origQuestion is set in case we get only CNAME without IP from rewrites table
 			break
@@ -378,11 +380,11 @@ func processFilteringAfterResponse(ctx *dnsContext) int {
 		if len(d.Res.Answer) != 0 {
 			answer := []dns.RR{}
 			answer = append(answer, s.genCNAMEAnswer(d.Req, res.CanonName))
-			answer = append(answer, d.Res.Answer...) // host -> IP
+			answer = append(answer, d.Res.Answer...)
 			d.Res.Answer = answer
 		}
 
-	case dnsfilter.NotFilteredWhiteList:
+	case dnsfilter.NotFilteredAllowList:
 		// nothing
 
 	default:

internal/dnsforward/dnsrewrite.go

@@ -0,0 +1,79 @@
+package dnsforward
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
+	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
+	"github.com/AdguardTeam/dnsproxy/proxy"
+	"github.com/AdguardTeam/golibs/log"
+	"github.com/AdguardTeam/urlfilter/rules"
+	"github.com/miekg/dns"
+)
+
+// filterDNSRewriteResponse handles a single DNS rewrite response entry.
+// It returns the constructed answer resource record.
+func (s *Server) filterDNSRewriteResponse(req *dns.Msg, rr rules.RRType, v rules.RRValue) (ans dns.RR, err error) {
+	switch rr {
+	case dns.TypeA, dns.TypeAAAA:
+		ip, ok := v.(net.IP)
+		if !ok {
+			return nil, fmt.Errorf("value has type %T, not net.IP", v)
+		}
+
+		if rr == dns.TypeA {
+			return s.genAAnswer(req, ip.To4()), nil
+		}
+
+		return s.genAAAAAnswer(req, ip), nil
+	case dns.TypeTXT:
+		str, ok := v.(string)
+		if !ok {
+			return nil, fmt.Errorf("value has type %T, not string", v)
+		}
+
+		return s.genTXTAnswer(req, []string{str}), nil
+	default:
+		log.Debug("don't know how to handle dns rr type %d, skipping", rr)
+
+		return nil, nil
+	}
+}
+
+// filterDNSRewrite handles dnsrewrite filters.  It constructs a DNS
+// response and sets it into d.Res.
+func (s *Server) filterDNSRewrite(req *dns.Msg, res dnsfilter.Result, d *proxy.DNSContext) (err error) {
+	resp := s.makeResponse(req)
+	dnsrr := res.DNSRewriteResult
+	if dnsrr == nil {
+		return agherr.Error("no dns rewrite rule content")
+	}
+
+	resp.Rcode = dnsrr.RCode
+	if resp.Rcode != dns.RcodeSuccess {
+		d.Res = resp
+
+		return nil
+	}
+
+	if dnsrr.Response == nil {
+		return agherr.Error("no dns rewrite rule responses")
+	}
+
+	rr := req.Question[0].Qtype
+	values := dnsrr.Response[rr]
+	for i, v := range values {
+		var ans dns.RR
+		ans, err = s.filterDNSRewriteResponse(req, rr, v)
+		if err != nil {
+			return fmt.Errorf("dns rewrite response for %d[%d]: %w", rr, i, err)
+		}
+
+		resp.Answer = append(resp.Answer, ans)
+	}
+
+	d.Res = resp
+
+	return nil
+}

internal/dnsforward/filter.go

@@ -42,7 +42,8 @@ func (s *Server) getClientRequestFilteringSettings(d *proxy.DNSContext) *dnsfilt
 	return &setts
 }
 
-// filterDNSRequest applies the dnsFilter and sets d.Res if the request was filtered
+// filterDNSRequest applies the dnsFilter and sets d.Res if the request
+// was filtered.
 func (s *Server) filterDNSRequest(ctx *dnsContext) (*dnsfilter.Result, error) {
 	d := ctx.proxyCtx
 	req := d.Req
@@ -54,9 +55,13 @@ func (s *Server) filterDNSRequest(ctx *dnsContext) (*dnsfilter.Result, error) {
 	} else if res.IsFiltered {
 		log.Tracef("Host %s is filtered, reason - %q, matched rule: %q", host, res.Reason, res.Rules[0].Text)
 		d.Res = s.genDNSFilterMessage(d, &res)
-	} else if res.Reason == dnsfilter.ReasonRewrite && len(res.CanonName) != 0 && len(res.IPList) == 0 {
+	} else if res.Reason.In(dnsfilter.ReasonRewrite, dnsfilter.DNSRewriteRule) &&
+		res.CanonName != "" &&
+		len(res.IPList) == 0 {
+		// Resolve the new canonical name, not the original host
+		// name.  The original question is readded in
+		// processFilteringAfterResponse.
 		ctx.origQuestion = d.Req.Question[0]
-		// resolve canonical name, not the original host name
 		d.Req.Question[0].Name = dns.Fqdn(res.CanonName)
 	} else if res.Reason == dnsfilter.RewriteAutoHosts && len(res.ReverseHosts) != 0 {
 		resp := s.makeResponse(req)
@@ -99,6 +104,11 @@ func (s *Server) filterDNSRequest(ctx *dnsContext) (*dnsfilter.Result, error) {
 		}
 
 		d.Res = resp
+	} else if res.Reason == dnsfilter.DNSRewriteRule {
+		err = s.filterDNSRewrite(req, res, d)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	return &res, err

internal/dnsforward/msg.go

@@ -11,12 +11,17 @@ import (
 )
 
 // Create a DNS response by DNS request and set necessary flags
-func (s *Server) makeResponse(req *dns.Msg) *dns.Msg {
+func (s *Server) makeResponse(req *dns.Msg) (resp *dns.Msg) {
-	resp := dns.Msg{}
+	resp = &dns.Msg{
+		MsgHdr: dns.MsgHdr{
+			RecursionAvailable: true,
+		},
+		Compress: true,
+	}
+
 	resp.SetReply(req)
-	resp.RecursionAvailable = true
+
-	resp.Compress = true
+	return resp
-	return &resp
 }
 
 // genDNSFilterMessage generates a DNS message corresponding to the filtering result
@@ -121,6 +126,18 @@ func (s *Server) genAAAAAnswer(req *dns.Msg, ip net.IP) *dns.AAAA {
 	return answer
 }
 
+func (s *Server) genTXTAnswer(req *dns.Msg, strs []string) (answer *dns.TXT) {
+	return &dns.TXT{
+		Hdr: dns.RR_Header{
+			Name:   req.Question[0].Name,
+			Rrtype: dns.TypeTXT,
+			Ttl:    s.conf.BlockedResponseTTL,
+			Class:  dns.ClassINET,
+		},
+		Txt: strs,
+	}
+}
+
 // generate DNS response message with an IP address
 func (s *Server) genResponseWithIP(req *dns.Msg, ip net.IP) *dns.Msg {
 	if req.Question[0].Qtype == dns.TypeA && ip.To4() != nil {

internal/dnsforward/stats.go

@@ -91,7 +91,7 @@ func (s *Server) updateStats(d *proxy.DNSContext, elapsed time.Duration, res dns
 	case dnsfilter.FilteredSafeSearch:
 		e.Result = stats.RSafeSearch
 
-	case dnsfilter.FilteredBlackList:
+	case dnsfilter.FilteredBlockList:
 		fallthrough
 	case dnsfilter.FilteredInvalid:
 		fallthrough

internal/home/controlfiltering.go

@@ -359,6 +359,9 @@ type checkHostResp struct {
 	// Deprecated: Use Rules[*].FilterListID.
 	FilterID int64 `json:"filter_id"`
 
+	// Rule is the text of the matched rule.
+	//
+	// Deprecated: Use Rules[*].Text.
 	Rule string `json:"rule"`
 
 	Rules []*checkHostRespRule `json:"rules"`
@@ -386,12 +389,15 @@ func (f *Filtering) handleCheckHost(w http.ResponseWriter, r *http.Request) {
 
 	resp := checkHostResp{}
 	resp.Reason = result.Reason.String()
-	resp.FilterID = result.Rules[0].FilterListID
-	resp.Rule = result.Rules[0].Text
 	resp.SvcName = result.ServiceName
 	resp.CanonName = result.CanonName
 	resp.IPList = result.IPList
 
+	if len(result.Rules) > 0 {
+		resp.FilterID = result.Rules[0].FilterListID
+		resp.Rule = result.Rules[0].Text
+	}
+
 	resp.Rules = make([]*checkHostRespRule, len(result.Rules))
 	for i, r := range result.Rules {
 		resp.Rules[i] = &checkHostRespRule{

internal/querylog/decode.go

@@ -4,11 +4,14 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"io"
+	"net"
 	"strings"
 	"time"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
 	"github.com/AdguardTeam/golibs/log"
+	"github.com/AdguardTeam/urlfilter/rules"
+	"github.com/miekg/dns"
 )
 
 type logEntryHandler (func(t json.Token, ent *logEntry) error)
@@ -165,13 +168,285 @@ var resultHandlers = map[string]logEntryHandler{
 		return nil
 	},
 	"ServiceName": func(t json.Token, ent *logEntry) error {
-		v, ok := t.(string)
+		s, ok := t.(string)
 		if !ok {
 			return nil
 		}
-		ent.Result.ServiceName = v
+
+		ent.Result.ServiceName = s
+
 		return nil
 	},
+	"CanonName": func(t json.Token, ent *logEntry) error {
+		s, ok := t.(string)
+		if !ok {
+			return nil
+		}
+
+		ent.Result.CanonName = s
+
+		return nil
+	},
+}
+
+func decodeResultRuleKey(key string, i int, dec *json.Decoder, ent *logEntry) {
+	switch key {
+	case "FilterListID":
+		vToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultRuleKey %s err: %s", key, err)
+			}
+
+			return
+		}
+
+		if len(ent.Result.Rules) < i+1 {
+			ent.Result.Rules = append(ent.Result.Rules, &dnsfilter.ResultRule{})
+		}
+
+		if n, ok := vToken.(json.Number); ok {
+			ent.Result.Rules[i].FilterListID, _ = n.Int64()
+		}
+	case "IP":
+		vToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultRuleKey %s err: %s", key, err)
+			}
+
+			return
+		}
+
+		if len(ent.Result.Rules) < i+1 {
+			ent.Result.Rules = append(ent.Result.Rules, &dnsfilter.ResultRule{})
+		}
+
+		if ipStr, ok := vToken.(string); ok {
+			ent.Result.Rules[i].IP = net.ParseIP(ipStr)
+		}
+	case "Text":
+		vToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultRuleKey %s err: %s", key, err)
+			}
+
+			return
+		}
+
+		if len(ent.Result.Rules) < i+1 {
+			ent.Result.Rules = append(ent.Result.Rules, &dnsfilter.ResultRule{})
+		}
+
+		if s, ok := vToken.(string); ok {
+			ent.Result.Rules[i].Text = s
+		}
+	default:
+		// Go on.
+	}
+}
+
+func decodeResultRules(dec *json.Decoder, ent *logEntry) {
+	for {
+		delimToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultRules err: %s", err)
+			}
+
+			return
+		}
+
+		if d, ok := delimToken.(json.Delim); ok {
+			if d != '[' {
+				log.Debug("decodeResultRules: unexpected delim %q", d)
+			}
+		} else {
+			return
+		}
+
+		i := 0
+		for {
+			keyToken, err := dec.Token()
+			if err != nil {
+				if err != io.EOF {
+					log.Debug("decodeResultRules err: %s", err)
+				}
+
+				return
+			}
+
+			if d, ok := keyToken.(json.Delim); ok {
+				if d == '}' {
+					i++
+				} else if d == ']' {
+					return
+				}
+
+				continue
+			}
+
+			key, ok := keyToken.(string)
+			if !ok {
+				log.Debug("decodeResultRules: keyToken is %T (%[1]v) and not string", keyToken)
+
+				return
+			}
+
+			decodeResultRuleKey(key, i, dec, ent)
+		}
+	}
+}
+
+func decodeResultReverseHosts(dec *json.Decoder, ent *logEntry) {
+	for {
+		itemToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultReverseHosts err: %s", err)
+			}
+
+			return
+		}
+
+		switch v := itemToken.(type) {
+		case json.Delim:
+			if v == '[' {
+				continue
+			} else if v == ']' {
+				return
+			}
+
+			log.Debug("decodeResultReverseHosts: unexpected delim %q", v)
+
+			return
+		case string:
+			ent.Result.ReverseHosts = append(ent.Result.ReverseHosts, v)
+		default:
+			continue
+		}
+	}
+}
+
+func decodeResultIPList(dec *json.Decoder, ent *logEntry) {
+	for {
+		itemToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultIPList err: %s", err)
+			}
+
+			return
+		}
+
+		switch v := itemToken.(type) {
+		case json.Delim:
+			if v == '[' {
+				continue
+			} else if v == ']' {
+				return
+			}
+
+			log.Debug("decodeResultIPList: unexpected delim %q", v)
+
+			return
+		case string:
+			ip := net.ParseIP(v)
+			if ip != nil {
+				ent.Result.IPList = append(ent.Result.IPList, ip)
+			}
+		default:
+			continue
+		}
+	}
+}
+
+func decodeResultDNSRewriteResult(dec *json.Decoder, ent *logEntry) {
+	for {
+		keyToken, err := dec.Token()
+		if err != nil {
+			if err != io.EOF {
+				log.Debug("decodeResultDNSRewriteResult err: %s", err)
+			}
+
+			return
+		}
+
+		if d, ok := keyToken.(json.Delim); ok {
+			if d == '}' {
+				return
+			}
+
+			continue
+		}
+
+		key, ok := keyToken.(string)
+		if !ok {
+			log.Debug("decodeResultDNSRewriteResult: keyToken is %T (%[1]v) and not string", keyToken)
+
+			return
+		}
+
+		// TODO(a.garipov): Refactor this into a separate
+		// function à la decodeResultRuleKey if we keep this
+		// code for a longer time than planned.
+		switch key {
+		case "RCode":
+			vToken, err := dec.Token()
+			if err != nil {
+				if err != io.EOF {
+					log.Debug("decodeResultDNSRewriteResult err: %s", err)
+				}
+
+				return
+			}
+
+			if ent.Result.DNSRewriteResult == nil {
+				ent.Result.DNSRewriteResult = &dnsfilter.DNSRewriteResult{}
+			}
+
+			if n, ok := vToken.(json.Number); ok {
+				rcode64, _ := n.Int64()
+				ent.Result.DNSRewriteResult.RCode = rules.RCode(rcode64)
+			}
+
+			continue
+		case "Response":
+			if ent.Result.DNSRewriteResult == nil {
+				ent.Result.DNSRewriteResult = &dnsfilter.DNSRewriteResult{}
+			}
+
+			if ent.Result.DNSRewriteResult.Response == nil {
+				ent.Result.DNSRewriteResult.Response = dnsfilter.DNSRewriteResultResponse{}
+			}
+
+			// TODO(a.garipov): I give up.  This whole file
+			// is a mess.  Luckily, we can assume that this
+			// field is relatively rare and just use the
+			// normal decoding and correct the values.
+			err = dec.Decode(&ent.Result.DNSRewriteResult.Response)
+			if err != nil {
+				log.Debug("decodeResultDNSRewriteResult response err: %s", err)
+			}
+
+			for rrType, rrValues := range ent.Result.DNSRewriteResult.Response {
+				switch rrType {
+				case dns.TypeA, dns.TypeAAAA:
+					for i, v := range rrValues {
+						s, _ := v.(string)
+						rrValues[i] = net.ParseIP(s)
+					}
+				default:
+					// Go on.
+				}
+			}
+
+			continue
+		default:
+			// Go on.
+		}
+	}
 }
 
 func decodeResult(dec *json.Decoder, ent *logEntry) {
@@ -200,6 +475,27 @@ func decodeResult(dec *json.Decoder, ent *logEntry) {
 			return
 		}
 
+		switch key {
+		case "ReverseHosts":
+			decodeResultReverseHosts(dec, ent)
+
+			continue
+		case "IPList":
+			decodeResultIPList(dec, ent)
+
+			continue
+		case "Rules":
+			decodeResultRules(dec, ent)
+
+			continue
+		case "DNSRewriteResult":
+			decodeResultDNSRewriteResult(dec, ent)
+
+			continue
+		default:
+			// Go on.
+		}
+
 		handler, ok := resultHandlers[key]
 		if !ok {
 			continue

internal/querylog/decode_test.go

@@ -2,95 +2,181 @@ package querylog
 
 import (
 	"bytes"
+	"encoding/base64"
+	"net"
 	"strings"
 	"testing"
+	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
 	"github.com/AdguardTeam/AdGuardHome/internal/testutil"
 	"github.com/AdguardTeam/golibs/log"
+	"github.com/AdguardTeam/urlfilter/rules"
+	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestDecode_decodeQueryLog(t *testing.T) {
+func TestDecodeLogEntry(t *testing.T) {
 	logOutput := &bytes.Buffer{}
 
 	testutil.ReplaceLogWriter(t, logOutput)
 	testutil.ReplaceLogLevel(t, log.DEBUG)
 
+	t.Run("success", func(t *testing.T) {
+		const ansStr = `Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==`
+		const data = `{"IP":"127.0.0.1",` +
+			`"T":"2020-11-25T18:55:56.519796+03:00",` +
+			`"QH":"an.yandex.ru",` +
+			`"QT":"A",` +
+			`"QC":"IN",` +
+			`"CP":"",` +
+			`"Answer":"` + ansStr + `",` +
+			`"Result":{` +
+			`"IsFiltered":true,` +
+			`"Reason":3,` +
+			`"ReverseHosts":["example.net"],` +
+			`"IPList":["127.0.0.2"],` +
+			`"Rules":[{"FilterListID":42,"Text":"||an.yandex.ru","IP":"127.0.0.2"},` +
+			`{"FilterListID":43,"Text":"||an2.yandex.ru","IP":"127.0.0.3"}],` +
+			`"CanonName":"example.com",` +
+			`"ServiceName":"example.org",` +
+			`"DNSRewriteResult":{"RCode":0,"Response":{"1":["127.0.0.2"]}}},` +
+			`"Elapsed":837429}`
+
+		ans, err := base64.StdEncoding.DecodeString(ansStr)
+		assert.Nil(t, err)
+
+		want := &logEntry{
+			IP:          "127.0.0.1",
+			Time:        time.Date(2020, 11, 25, 15, 55, 56, 519796000, time.UTC),
+			QHost:       "an.yandex.ru",
+			QType:       "A",
+			QClass:      "IN",
+			ClientProto: "",
+			Answer:      ans,
+			Result: dnsfilter.Result{
+				IsFiltered:   true,
+				Reason:       dnsfilter.FilteredBlockList,
+				ReverseHosts: []string{"example.net"},
+				IPList:       []net.IP{net.IPv4(127, 0, 0, 2)},
+				Rules: []*dnsfilter.ResultRule{{
+					FilterListID: 42,
+					Text:         "||an.yandex.ru",
+					IP:           net.IPv4(127, 0, 0, 2),
+				}, {
+					FilterListID: 43,
+					Text:         "||an2.yandex.ru",
+					IP:           net.IPv4(127, 0, 0, 3),
+				}},
+				CanonName:   "example.com",
+				ServiceName: "example.org",
+				DNSRewriteResult: &dnsfilter.DNSRewriteResult{
+					RCode: dns.RcodeSuccess,
+					Response: dnsfilter.DNSRewriteResultResponse{
+						dns.TypeA: []rules.RRValue{net.IPv4(127, 0, 0, 2)},
+					},
+				},
+			},
+			Elapsed: 837429,
+		}
+
+		got := &logEntry{}
+		decodeLogEntry(got, data)
+
+		s := logOutput.String()
+		assert.Equal(t, "", s)
+
+		// Correct for time zones.
+		got.Time = got.Time.UTC()
+		assert.Equal(t, want, got)
+	})
+
 	testCases := []struct {
 		name string
 		log  string
 		want string
 	}{{
-		name: "all_right",
+		name: "all_right_old_rule",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1,"ReverseHosts":["example.com"],"IPList":["127.0.0.1"]},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
-		name: "bad_filter_id",
+		name: "bad_filter_id_old_rule",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1.5},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"FilterID":1.5},"Elapsed":837429}`,
 		want: "decodeResult handler err: strconv.ParseInt: parsing \"1.5\": invalid syntax\n",
 	}, {
 		name: "bad_is_filtered",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":trooe,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":trooe,"Reason":3},"Elapsed":837429}`,
 		want: "decodeLogEntry err: invalid character 'o' in literal true (expecting 'u')\n",
 	}, {
 		name: "bad_elapsed",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":-1}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":-1}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_ip",
-		log:  `{"IP":127001,"T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":127001,"T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_time",
-		log:  `{"IP":"127.0.0.1","T":"12/09/1998T15:00:00.000000+05:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"12/09/1998T15:00:00.000000+05:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
 		want: "decodeLogEntry handler err: parsing time \"12/09/1998T15:00:00.000000+05:00\" as \"2006-01-02T15:04:05Z07:00\": cannot parse \"9/1998T15:00:00.000000+05:00\" as \"2006\"\n",
 	}, {
 		name: "bad_host",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":6,"QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":6,"QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_type",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":true,"QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":true,"QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_class",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":false,"CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":false,"CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_client_proto",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":8,"Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":8,"Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "very_bad_client_proto",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"dog","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"dog","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
 		want: "decodeLogEntry handler err: invalid client proto: \"dog\"\n",
 	}, {
 		name: "bad_answer",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":0.9,"Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":0.9,"Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "very_bad_answer",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3},"Elapsed":837429}`,
 		want: "decodeLogEntry handler err: illegal base64 data at input byte 61\n",
 	}, {
 		name: "bad_rule",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":false,"FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"Rule":false},"Elapsed":837429}`,
-		want: "default",
+		want: "",
 	}, {
 		name: "bad_reason",
-		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":true,"Rule":"||an.yandex.","FilterID":1},"Elapsed":837429}`,
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":true},"Elapsed":837429}`,
-		want: "default",
+		want: "",
+	}, {
+		name: "bad_reverse_hosts",
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"ReverseHosts":[{}]},"Elapsed":837429}`,
+		want: "decodeResultReverseHosts: unexpected delim \"{\"\n",
+	}, {
+		name: "bad_ip_list",
+		log:  `{"IP":"127.0.0.1","T":"2020-11-25T18:55:56.519796+03:00","QH":"an.yandex.ru","QT":"A","QC":"IN","CP":"","Answer":"Qz+BgAABAAEAAAAAAmFuBnlhbmRleAJydQAAAQABwAwAAQABAAAACgAEAAAAAA==","Result":{"IsFiltered":true,"Reason":3,"ReverseHosts":["example.net"],"IPList":[{}]},"Elapsed":837429}`,
+		want: "decodeResultIPList: unexpected delim \"{\"\n",
 	}}
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			_, err := logOutput.Write([]byte("default"))
-			assert.Nil(t, err)
-
 			l := &logEntry{}
 			decodeLogEntry(l, tc.log)
 
-			assert.True(t, strings.HasSuffix(logOutput.String(), tc.want), "%q\ndoes not end with\n%q", logOutput.String(), tc.want)
+			s := logOutput.String()
+			if tc.want == "" {
+				assert.Equal(t, "", s)
+			} else {
+				assert.True(t, strings.HasSuffix(s, tc.want),
+					"got %q", s)
+			}
 
 			logOutput.Reset()
 		})

internal/querylog/searchcriteria.go

@@ -115,14 +115,14 @@ func (c *searchCriteria) ctFilteringStatusCase(res dnsfilter.Result) bool {
 	case filteringStatusFiltered:
 		return res.IsFiltered ||
 			res.Reason.In(
-				dnsfilter.NotFilteredWhiteList,
+				dnsfilter.NotFilteredAllowList,
 				dnsfilter.ReasonRewrite,
 				dnsfilter.RewriteAutoHosts,
 			)
 
 	case filteringStatusBlocked:
 		return res.IsFiltered &&
-			res.Reason.In(dnsfilter.FilteredBlackList, dnsfilter.FilteredBlockedService)
+			res.Reason.In(dnsfilter.FilteredBlockList, dnsfilter.FilteredBlockedService)
 
 	case filteringStatusBlockedService:
 		return res.IsFiltered && res.Reason == dnsfilter.FilteredBlockedService
@@ -134,7 +134,7 @@ func (c *searchCriteria) ctFilteringStatusCase(res dnsfilter.Result) bool {
 		return res.IsFiltered && res.Reason == dnsfilter.FilteredSafeBrowsing
 
 	case filteringStatusWhitelisted:
-		return res.Reason == dnsfilter.NotFilteredWhiteList
+		return res.Reason == dnsfilter.NotFilteredAllowList
 
 	case filteringStatusRewritten:
 		return res.Reason.In(dnsfilter.ReasonRewrite, dnsfilter.RewriteAutoHosts)
@@ -144,9 +144,9 @@ func (c *searchCriteria) ctFilteringStatusCase(res dnsfilter.Result) bool {
 
 	case filteringStatusProcessed:
 		return !res.Reason.In(
-			dnsfilter.FilteredBlackList,
+			dnsfilter.FilteredBlockList,
 			dnsfilter.FilteredBlockedService,
-			dnsfilter.NotFilteredWhiteList,
+			dnsfilter.NotFilteredAllowList,
 		)
 
 	default:

openapi/CHANGELOG.md

@@ -4,15 +4,21 @@
 
 ## v0.105: API changes
 
+### New `"reason"` in `GET /filtering/check_host` and `GET /querylog`
+
+* The new `DNSRewriteRule` reason is added to `GET /filtering/check_host` and
+  `GET /querylog`.
+
+* Also, the reason which was incorrectly documented as `"ReasonRewrite"` is now
+  correctly documented as `"Rewrite"`, and the previously undocumented
+  `"RewriteEtcHosts"` is now documented as well.
+
 ### Multiple matched rules in `GET /filtering/check_host` and `GET /querylog`
 
-<!-- TODO(a.garipov): Update with better examples once $dnsrewrite rules are
-checked in. -->
-
 * The properties `rule` and `filter_id` are now deprecated.  API users should
-  inspect the newly-added `rules` object array instead.  Currently, it's either
+  inspect the newly-added `rules` object array instead.  For most rules, it's
-  empty or contains one object, which contains the same things as the old two
+  either empty or contains one object, which contains the same things as the old
-  properties did, but under more correct names:
+  two properties did, but under more correct names:
 
   ```js
   {
@@ -30,6 +36,30 @@ checked in. -->
   }
   ```
 
+  For `$dnsrewrite` rules, they contain all rules that contributed to the
+  result.  For example, if you have the following filtering rules:
+
+  ```
+  ||example.com^$dnsrewrite=127.0.0.1
+  ||example.com^$dnsrewrite=127.0.0.2
+  ```
+
+  The `"rules"` will be something like:
+
+  ```js
+  {
+    // …
+
+    "rules": [{
+      "text": "||example.com^$dnsrewrite=127.0.0.1",
+      "filter_list_id": 0
+    }, {
+      "text": "||example.com^$dnsrewrite=127.0.0.2",
+      "filter_list_id": 0
+    }]
+  }
+  ```
+
   The old fields will be removed in v0.106.0.
 
 ## v0.103: API changes

openapi/openapi.yaml

@@ -523,7 +523,7 @@
         Reload filtering rules from URLs.  This might be needed if new URL was
         just added and you dont want to wait for automatic refresh to kick in.
         This API request is ratelimited, so you can call it freely as often as
-        you like, it wont create unneccessary burden on servers that host the
+        you like, it wont create unnecessary burden on servers that host the
         URL.  This should work as intended, a `force` parameter is offered as
         last-resort attempt to make filter lists fresh.  If you ever find
         yourself using `force` to make something work that otherwise wont, this
@@ -1246,7 +1246,7 @@
       'properties':
         'reason':
           'type': 'string'
-          'description': 'DNS filter status'
+          'description': 'Request filtering status.'
           'enum':
           - 'NotFilteredNotFound'
           - 'NotFilteredWhiteList'
@@ -1257,7 +1257,9 @@
           - 'FilteredInvalid'
           - 'FilteredSafeSearch'
           - 'FilteredBlockedService'
-          - 'ReasonRewrite'
+          - 'Rewrite'
+          - 'RewriteEtcHosts'
+          - 'DNSRewriteRule'
         'filter_id':
           'deprecated': true
           'description': >
@@ -1284,12 +1286,12 @@
           'description': 'Set if reason=FilteredBlockedService'
         'cname':
           'type': 'string'
-          'description': 'Set if reason=ReasonRewrite'
+          'description': 'Set if reason=Rewrite'
         'ip_addrs':
           'type': 'array'
           'items':
             'type': 'string'
-          'description': 'Set if reason=ReasonRewrite'
+          'description': 'Set if reason=Rewrite'
     'FilterRefreshResponse':
       'type': 'object'
       'description': '/filtering/refresh response data'
@@ -1648,7 +1650,7 @@
             '$ref': '#/components/schemas/ResultRule'
         'reason':
           'type': 'string'
-          'description': 'DNS filter status'
+          'description': 'Request filtering status.'
           'enum':
           - 'NotFilteredNotFound'
           - 'NotFilteredWhiteList'
@@ -1659,7 +1661,9 @@
           - 'FilteredInvalid'
           - 'FilteredSafeSearch'
           - 'FilteredBlockedService'
-          - 'ReasonRewrite'
+          - 'Rewrite'
+          - 'RewriteEtcHosts'
+          - 'DNSRewriteRule'
         'service_name':
           'type': 'string'
           'description': 'Set if reason=FilteredBlockedService'

scripts/go-lint.sh

@@ -95,7 +95,7 @@ ineffassign .
 
 unparam ./...
 
-misspell --error ./...
+git ls-files -- '*.go' '*.md' '*.yaml' '*.yml' | xargs misspell --error
 
 looppointer ./...
 

scripts/translations/README.md

@@ -1,4 +1,4 @@
-## Twosky intergration script
+## Twosky integration script
 
 ### Usage