chore: check fake-ip-range and fake-ip-range6 are indeed ipv4 and ipv6 prefixes

config/config.go

@@ -685,6 +685,8 @@ func ParseRawConfig(rawCfg *RawConfig) (*Config, error) {
 	}
 	config.Hosts = hosts
 
+	parseIPV6(rawCfg) // must before DNS and Tun
+
 	dnsCfg, err := parseDNS(rawCfg, ruleProviders)
 	if err != nil {
 		return nil, err
@@ -1417,6 +1419,9 @@ func parseDNS(rawCfg *RawConfig, ruleProviders map[string]providerTypes.RuleProv
 		if err != nil {
 			return nil, err
 		}
+		if !dnsCfg.FakeIPRange.Addr().Is4() {
+			return nil, errors.New("dns.fake-ip-range must be a IPv4 prefix")
+		}
 	}
 
 	if cfg.FakeIPRange6 != "" {
@@ -1424,6 +1429,9 @@ func parseDNS(rawCfg *RawConfig, ruleProviders map[string]providerTypes.RuleProv
 		if err != nil {
 			return nil, err
 		}
+		if !dnsCfg.FakeIPRange6.Addr().Is6() {
+			return nil, errors.New("dns.fake-ip-range6 must be a IPv6 prefix")
+		}
 	}
 
 	if cfg.EnhancedMode == C.DNSFakeIP {
@@ -1538,17 +1546,20 @@ func parseAuthentication(rawRecords []string) []auth.AuthUser {
 	return users
 }
 
+func parseIPV6(rawCfg *RawConfig) {
+	if !rawCfg.IPv6 || !verifyIP6() {
+		rawCfg.DNS.FakeIPRange6 = ""
+		rawCfg.Tun.Inet6Address = nil
+	}
+}
+
 func parseTun(rawTun RawTun, dns *DNS, general *General) error {
 	tunAddressPrefix := dns.FakeIPRange
-	if !tunAddressPrefix.IsValid() || !tunAddressPrefix.Addr().Is4() {
+	if !tunAddressPrefix.IsValid() {
 		tunAddressPrefix = netip.MustParsePrefix("198.18.0.1/16")
 	}
 	tunAddressPrefix = netip.PrefixFrom(tunAddressPrefix.Addr(), 30)
 
-	if !general.IPv6 || !verifyIP6() {
-		rawTun.Inet6Address = nil
-	}
-
 	general.Tun = LC.Tun{
 		Enable:              rawTun.Enable,
 		Device:              rawTun.Device,