passt, funktion unklar

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bufio"
 	"context"
+	"encoding/binary"
 	"encoding/json"
 	"expvar"
 	"fmt"
@@ -151,31 +152,79 @@ func handleCheck(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+// liefert alle möglichen Präfixe dieser IP, beginnend beim längsten (/32 oder /128)
+func supernets(ip netip.Addr) []string {
+	if ip.Is4() {
+		a := ip.As4()                      // Kopie addressierbar machen
+		u := binary.BigEndian.Uint32(a[:]) // jetzt darf man slicen
+
+		supers := make([]string, 33) // /32 … /0
+		for bits := 32; bits >= 0; bits-- {
+			mask := uint32(0xffffffff) << (32 - bits)
+			n := u & mask
+			addr := netip.AddrFrom4([4]byte{
+				byte(n >> 24), byte(n >> 16), byte(n >> 8), byte(n),
+			})
+			supers[32-bits] = fmt.Sprintf("%s/%d", addr, bits)
+		}
+		return supers
+	}
+
+	a := ip.As16()                // Kopie addressierbar
+	supers := make([]string, 129) // /128 … /0
+	for bits := 128; bits >= 0; bits-- {
+		b := a // Wert-Kopie für Modifikation
+
+		// vollständige Bytes auf 0 setzen
+		full := (128 - bits) / 8
+		for i := 0; i < full; i++ {
+			b[15-i] = 0
+		}
+		// Restbits maskieren
+		rem := (128 - bits) % 8
+		if rem != 0 {
+			b[15-full] &= 0xFF << rem
+		}
+
+		addr := netip.AddrFrom16(b)
+		supers[128-bits] = fmt.Sprintf("%s/%d", addr, bits)
+	}
+	return supers
+}
+
 func checkIP(ip netip.Addr, cats []string) ([]string, error) {
 	if res, ok := ipCache.Get(ip.String()); ok {
 		hits.Add(1)
 		return res, nil
 	}
 
-	matches := []string{}
+	supers := supernets(ip)
+	pipe := rdb.Pipeline()
+	cmds := make([]*redis.IntCmd, 0, len(cats)*len(supers))
+
+	// *einen* Redis-Roundtrip bauen
 	for _, cat := range cats {
-		iter := rdb.Scan(ctx, 0, "bl:"+cat+":*", 0).Iterator()
-		for iter.Next(ctx) {
-			key := iter.Val()
-			parts := strings.SplitN(key, ":", 3)
-			if len(parts) != 3 {
-				continue
-			}
-			pfx, err := netip.ParsePrefix(parts[2])
-			if err != nil {
-				continue
-			}
-			if pfx.Contains(ip) {
-				matches = append(matches, cat)
-				break
-			}
+		for _, pfx := range supers {
+			key := "bl:" + cat + ":" + pfx
+			cmds = append(cmds, pipe.Exists(ctx, key))
 		}
 	}
+	if _, err := pipe.Exec(ctx); err != nil && err != redis.Nil {
+		return nil, err
+	}
+
+	matches := make([]string, 0, len(cats))
+	idx := 0
+	for _, cat := range cats {
+		for range supers {
+			if cmds[idx].Val() == 1 {
+				matches = append(matches, cat)
+				break // Kategorie gefunden → nächste
+			}
+			idx++
+		}
+	}
+
 	misses.Add(1)
 	ipCache.Add(ip.String(), matches)
 	return matches, nil