Independent source_ip_is_private and ip_is_private rules

route/rule_default.go

@@ -120,6 +120,11 @@ func NewDefaultRule(router adapter.Router, logger log.ContextLogger, options opt
 		rule.sourceAddressItems = append(rule.sourceAddressItems, item)
 		rule.allItems = append(rule.allItems, item)
 	}
+	if options.SourceIPIsPrivate {
+		item := NewIPIsPrivateItem(true)
+		rule.sourceAddressItems = append(rule.sourceAddressItems, item)
+		rule.allItems = append(rule.allItems, item)
+	}
 	if len(options.IPCIDR) > 0 {
 		item, err := NewIPCIDRItem(false, options.IPCIDR)
 		if err != nil {
@@ -128,6 +133,11 @@ func NewDefaultRule(router adapter.Router, logger log.ContextLogger, options opt
 		rule.destinationAddressItems = append(rule.destinationAddressItems, item)
 		rule.allItems = append(rule.allItems, item)
 	}
+	if options.IPIsPrivate {
+		item := NewIPIsPrivateItem(false)
+		rule.destinationAddressItems = append(rule.destinationAddressItems, item)
+		rule.allItems = append(rule.allItems, item)
+	}
 	if len(options.SourcePort) > 0 {
 		item := NewPortItem(true, options.SourcePort)
 		rule.sourcePortItems = append(rule.sourcePortItems, item)

route/rule_dns.go

@@ -119,6 +119,11 @@ func NewDefaultDNSRule(router adapter.Router, logger log.ContextLogger, options
 		rule.sourceAddressItems = append(rule.sourceAddressItems, item)
 		rule.allItems = append(rule.allItems, item)
 	}
+	if options.SourceIPIsPrivate {
+		item := NewIPIsPrivateItem(true)
+		rule.sourceAddressItems = append(rule.sourceAddressItems, item)
+		rule.allItems = append(rule.allItems, item)
+	}
 	if len(options.SourcePort) > 0 {
 		item := NewPortItem(true, options.SourcePort)
 		rule.sourcePortItems = append(rule.sourcePortItems, item)

route/rule_item_ip_is_private.go

@@ -0,0 +1,44 @@
+package route
+
+import (
+	"net/netip"
+
+	"github.com/sagernet/sing-box/adapter"
+	N "github.com/sagernet/sing/common/network"
+)
+
+var _ RuleItem = (*IPIsPrivateItem)(nil)
+
+type IPIsPrivateItem struct {
+	isSource bool
+}
+
+func NewIPIsPrivateItem(isSource bool) *IPIsPrivateItem {
+	return &IPIsPrivateItem{isSource}
+}
+
+func (r *IPIsPrivateItem) Match(metadata *adapter.InboundContext) bool {
+	var destination netip.Addr
+	if r.isSource {
+		destination = metadata.Source.Addr
+	} else {
+		destination = metadata.Destination.Addr
+	}
+	if destination.IsValid() && !N.IsPublicAddr(destination) {
+		return true
+	}
+	for _, destinationAddress := range metadata.DestinationAddresses {
+		if !N.IsPublicAddr(destinationAddress) {
+			return true
+		}
+	}
+	return false
+}
+
+func (r *IPIsPrivateItem) String() string {
+	if r.isSource {
+		return "source_ip_is_private=true"
+	} else {
+		return "ip_is_private=true"
+	}
+}