all: sync with master; upd chlog

internal/aghnet/addr.go

@@ -0,0 +1,43 @@
+package aghnet
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/AdguardTeam/golibs/stringutil"
+)
+
+// NormalizeDomain returns a lowercased version of host without the final dot,
+// unless host is ".", in which case it returns it unchanged.  That is a special
+// case that to allow matching queries like:
+//
+//	dig IN NS '.'
+func NormalizeDomain(host string) (norm string) {
+	if host == "." {
+		return host
+	}
+
+	return strings.ToLower(strings.TrimSuffix(host, "."))
+}
+
+// NewDomainNameSet returns nil and error, if list has duplicate or empty domain
+// name.  Otherwise returns a set, which contains domain names normalized using
+// [NormalizeDomain].
+func NewDomainNameSet(list []string) (set *stringutil.Set, err error) {
+	set = stringutil.NewSet()
+
+	for i, host := range list {
+		if host == "" {
+			return nil, fmt.Errorf("at index %d: hostname is empty", i)
+		}
+
+		host = NormalizeDomain(host)
+		if set.Has(host) {
+			return nil, fmt.Errorf("duplicate hostname %q at index %d", host, i)
+		}
+
+		set.Add(host)
+	}
+
+	return set, nil
+}