all: sync with master; upd chlog

internal/aghnet/hostgen.go

@@ -1,47 +1,14 @@
 package aghnet
 
 import (
-	"net"
-	"strconv"
+	"fmt"
+	"net/netip"
+	"strings"
+
+	"github.com/AdguardTeam/golibs/errors"
+	"github.com/AdguardTeam/golibs/stringutil"
 )
 
-// The maximum lengths of generated hostnames for different IP versions.
-const (
-	ipv4HostnameMaxLen = len("192-168-100-100")
-	ipv6HostnameMaxLen = len("ff80-f076-0000-0000-0000-0000-0000-0010")
-)
-
-// generateIPv4Hostname generates the hostname by IP address version 4.
-func generateIPv4Hostname(ipv4 net.IP) (hostname string) {
-	hnData := make([]byte, 0, ipv4HostnameMaxLen)
-	for i, part := range ipv4 {
-		if i > 0 {
-			hnData = append(hnData, '-')
-		}
-		hnData = strconv.AppendUint(hnData, uint64(part), 10)
-	}
-
-	return string(hnData)
-}
-
-// generateIPv6Hostname generates the hostname by IP address version 6.
-func generateIPv6Hostname(ipv6 net.IP) (hostname string) {
-	hnData := make([]byte, 0, ipv6HostnameMaxLen)
-	for i, partsNum := 0, net.IPv6len/2; i < partsNum; i++ {
-		if i > 0 {
-			hnData = append(hnData, '-')
-		}
-		for _, val := range ipv6[i*2 : i*2+2] {
-			if val < 10 {
-				hnData = append(hnData, '0')
-			}
-			hnData = strconv.AppendUint(hnData, uint64(val), 16)
-		}
-	}
-
-	return string(hnData)
-}
-
 // GenerateHostname generates the hostname from ip.  In case of using IPv4 the
 // result should be like:
 //
@@ -52,10 +19,42 @@ func generateIPv6Hostname(ipv6 net.IP) (hostname string) {
 //	ff80-f076-0000-0000-0000-0000-0000-0010
 //
 // ip must be either an IPv4 or an IPv6.
-func GenerateHostname(ip net.IP) (hostname string) {
-	if ipv4 := ip.To4(); ipv4 != nil {
-		return generateIPv4Hostname(ipv4)
+func GenerateHostname(ip netip.Addr) (hostname string) {
+	if !ip.IsValid() {
+		// TODO(s.chzhen):  Get rid of it.
+		panic("aghnet generate hostname: invalid ip")
 	}
 
-	return generateIPv6Hostname(ip)
+	ip = ip.Unmap()
+	hostname = ip.StringExpanded()
+
+	if ip.Is4() {
+		return strings.Replace(hostname, ".", "-", -1)
+	}
+
+	return strings.Replace(hostname, ":", "-", -1)
+}
+
+// NewDomainNameSet returns nil and error, if list has duplicate or empty
+// domain name.  Otherwise returns a set, which contains non-FQDN domain names,
+// and nil error.
+func NewDomainNameSet(list []string) (set *stringutil.Set, err error) {
+	set = stringutil.NewSet()
+
+	for i, v := range list {
+		host := strings.ToLower(strings.TrimSuffix(v, "."))
+		// TODO(a.garipov): Think about ignoring empty (".") names in the
+		// future.
+		if host == "" {
+			return nil, errors.Error("host name is empty")
+		}
+
+		if set.Has(host) {
+			return nil, fmt.Errorf("duplicate host name %q at index %d", host, i)
+		}
+
+		set.Add(host)
+	}
+
+	return set, nil
 }