cherry-pick: upd-go

Merge in DNS/adguard-home from upd-go to master

Squashed commit of the following:

commit 8edfb5cc3466c1e4ee2eacae5157bd93c135a284
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Aug 3 14:25:45 2022 +0300

    all: imp docs; fmt

commit 080b8a85c02afbdaa079c0da47cb7b6311d50fbe
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Tue Aug 2 20:51:20 2022 +0300

    all: upd go, imp generic code

internal/dnsforward/access.go

@@ -214,7 +214,7 @@ func validateAccessSet(list *accessListJSON) (err error) {
 	}
 
 	merged := allowed.Merge(disallowed)
-	err = merged.Validate(aghalg.StringIsBefore)
+	err = merged.Validate()
 	if err != nil {
 		return fmt.Errorf("items in allowed and disallowed clients intersect: %w", err)
 	}
@@ -223,13 +223,13 @@ func validateAccessSet(list *accessListJSON) (err error) {
 }
 
 // validateStrUniq returns an informative error if clients are not unique.
-func validateStrUniq(clients []string) (uc aghalg.UniqChecker, err error) {
-	uc = make(aghalg.UniqChecker, len(clients))
+func validateStrUniq(clients []string) (uc aghalg.UniqChecker[string], err error) {
+	uc = make(aghalg.UniqChecker[string], len(clients))
 	for _, c := range clients {
 		uc.Add(c)
 	}
 
-	return uc, uc.Validate(aghalg.StringIsBefore)
+	return uc, uc.Validate()
 }
 
 func (s *Server) handleAccessSet(w http.ResponseWriter, r *http.Request) {

internal/dnsforward/dns.go

@@ -409,7 +409,7 @@ func (s *Server) ipToHost(ip net.IP) (host string, ok bool) {
 		return "", false
 	}
 
-	var v interface{}
+	var v any
 	v, ok = s.tableIPToHost.Get(ip)
 	if !ok {
 		return "", false

internal/dnsforward/dnsforward_test.go

@@ -988,7 +988,7 @@ func TestRewrite(t *testing.T) {
 	}
 }
 
-func publicKey(priv interface{}) interface{} {
+func publicKey(priv any) any {
 	switch k := priv.(type) {
 	case *rsa.PrivateKey:
 		return &k.PublicKey

internal/dnsforward/http.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net"
 	"net/http"
-	"sort"
 	"strings"
 	"time"
 
@@ -17,6 +16,8 @@ import (
 	"github.com/AdguardTeam/golibs/netutil"
 	"github.com/AdguardTeam/golibs/stringutil"
 	"github.com/miekg/dns"
+	"golang.org/x/exp/maps"
+	"golang.org/x/exp/slices"
 )
 
 type dnsConfig struct {
@@ -401,20 +402,6 @@ func ValidateUpstreams(upstreams []string) (err error) {
 	return err
 }
 
-// stringKeysSorted returns the sorted slice of string keys of m.
-//
-// TODO(e.burkov):  Use generics in Go 1.18.  Move into golibs.
-func stringKeysSorted(m map[string][]upstream.Upstream) (sorted []string) {
-	sorted = make([]string, 0, len(m))
-	for s := range m {
-		sorted = append(sorted, s)
-	}
-
-	sort.Strings(sorted)
-
-	return sorted
-}
-
 // ValidateUpstreamsPrivate validates each upstream and returns an error if any
 // upstream is invalid or if there are no default upstreams specified.  It also
 // checks each domain of domain-specific upstreams for being ARPA pointing to
@@ -429,9 +416,11 @@ func ValidateUpstreamsPrivate(upstreams []string, privateNets netutil.SubnetSet)
 		return nil
 	}
 
-	var errs []error
+	keys := maps.Keys(conf.DomainReservedUpstreams)
+	slices.Sort(keys)
 
-	for _, domain := range stringKeysSorted(conf.DomainReservedUpstreams) {
+	var errs []error
+	for _, domain := range keys {
 		var subnet *net.IPNet
 		subnet, err = netutil.SubnetFromReversedAddr(domain)
 		if err != nil {

internal/dnsforward/http_test.go

@@ -34,7 +34,7 @@ func (fsr *fakeSystemResolvers) Get() (rs []string) {
 	return nil
 }
 
-func loadTestData(t *testing.T, casesFileName string, cases interface{}) {
+func loadTestData(t *testing.T, casesFileName string, cases any) {
 	t.Helper()
 
 	var f *os.File