Add rewriteTo

clients/clients.go

@@ -37,6 +37,7 @@ type WgConfig struct {
 type Target struct {
 	SourcePrefix string      `json:"sourcePrefix"`
 	DestPrefix   string      `json:"destPrefix"`
+	RewriteTo    string      `json:"rewriteTo,omitempty"`
 	PortRange    []PortRange `json:"portRange,omitempty"`
 }
 
@@ -472,6 +473,15 @@ func (s *WireGuardService) ensureTargets(targets []Target) error {
 			return fmt.Errorf("invalid CIDR %s: %v", target.DestPrefix, err)
 		}
 
+		var rewriteTo netip.Prefix
+		if target.RewriteTo != "" {
+			rewriteTo, err = netip.ParsePrefix(target.RewriteTo)
+			if err != nil {
+				logger.Info("Invalid CIDR %s: %v", target.RewriteTo, err)
+				continue
+			}
+		}
+
 		var portRanges []netstack2.PortRange
 		for _, pr := range target.PortRange {
 			portRanges = append(portRanges, netstack2.PortRange{
@@ -480,7 +490,7 @@ func (s *WireGuardService) ensureTargets(targets []Target) error {
 			})
 		}
 
-		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, portRanges)
+		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, rewriteTo, portRanges)
 
 		logger.Info("Added target subnet from %s to %s with port ranges: %v", target.SourcePrefix, target.DestPrefix, target.PortRange)
 	}
@@ -864,6 +874,15 @@ func (s *WireGuardService) handleAddTarget(msg websocket.WSMessage) {
 			continue
 		}
 
+		var rewriteTo netip.Prefix
+		if target.RewriteTo != "" {
+			rewriteTo, err = netip.ParsePrefix(target.RewriteTo)
+			if err != nil {
+				logger.Info("Invalid CIDR %s: %v", target.RewriteTo, err)
+				continue
+			}
+		}
+
 		var portRanges []netstack2.PortRange
 		for _, pr := range target.PortRange {
 			portRanges = append(portRanges, netstack2.PortRange{
@@ -872,7 +891,7 @@ func (s *WireGuardService) handleAddTarget(msg websocket.WSMessage) {
 			})
 		}
 
-		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, portRanges)
+		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, rewriteTo, portRanges)
 
 		logger.Info("Added target subnet from %s to %s with port ranges: %v", target.SourcePrefix, target.DestPrefix, target.PortRange)
 	}
@@ -979,6 +998,15 @@ func (s *WireGuardService) handleUpdateTarget(msg websocket.WSMessage) {
 			continue
 		}
 
+		var rewriteTo netip.Prefix
+		if target.RewriteTo != "" {
+			rewriteTo, err = netip.ParsePrefix(target.RewriteTo)
+			if err != nil {
+				logger.Info("Invalid CIDR %s: %v", target.RewriteTo, err)
+				continue
+			}
+		}
+
 		var portRanges []netstack2.PortRange
 		for _, pr := range target.PortRange {
 			portRanges = append(portRanges, netstack2.PortRange{
@@ -987,7 +1015,7 @@ func (s *WireGuardService) handleUpdateTarget(msg websocket.WSMessage) {
 			})
 		}
 
-		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, portRanges)
+		s.tnet.AddProxySubnetRule(sourcePrefix, destPrefix, rewriteTo, portRanges)
 		logger.Info("Added target subnet from %s to %s with port ranges: %v", target.SourcePrefix, target.DestPrefix, target.PortRange)
 	}
 }

netstack2/proxy.go

@@ -27,6 +27,7 @@ type PortRange struct {
 type SubnetRule struct {
 	SourcePrefix netip.Prefix // Source IP prefix (who is sending)
 	DestPrefix   netip.Prefix // Destination IP prefix (where it's going)
+	RewriteTo    netip.Prefix // Optional rewrite address for destination
 	PortRanges   []PortRange  // empty slice means all ports allowed
 }
 
@@ -51,7 +52,7 @@ func NewSubnetLookup() *SubnetLookup {
 
 // AddSubnet adds a subnet rule with source and destination prefixes and optional port restrictions
 // If portRanges is nil or empty, all ports are allowed for this subnet
-func (sl *SubnetLookup) AddSubnet(sourcePrefix, destPrefix netip.Prefix, portRanges []PortRange) {
+func (sl *SubnetLookup) AddSubnet(sourcePrefix, destPrefix, rewriteTo netip.Prefix, portRanges []PortRange) {
 	sl.mu.Lock()
 	defer sl.mu.Unlock()
 
@@ -63,6 +64,7 @@ func (sl *SubnetLookup) AddSubnet(sourcePrefix, destPrefix netip.Prefix, portRan
 	sl.rules[key] = &SubnetRule{
 		SourcePrefix: sourcePrefix,
 		DestPrefix:   destPrefix,
+		RewriteTo:    rewriteTo,
 		PortRanges:   portRanges,
 	}
 }
@@ -200,11 +202,11 @@ func NewProxyHandler(options ProxyHandlerOptions) (*ProxyHandler, error) {
 // sourcePrefix: The IP prefix of the peer sending the data
 // destPrefix: The IP prefix of the destination
 // If portRanges is nil or empty, all ports are allowed for this subnet
-func (p *ProxyHandler) AddSubnetRule(sourcePrefix, destPrefix netip.Prefix, portRanges []PortRange) {
+func (p *ProxyHandler) AddSubnetRule(sourcePrefix, destPrefix, rewriteTo netip.Prefix, portRanges []PortRange) {
 	if p == nil || !p.enabled {
 		return
 	}
-	p.subnetLookup.AddSubnet(sourcePrefix, destPrefix, portRanges)
+	p.subnetLookup.AddSubnet(sourcePrefix, destPrefix, rewriteTo, portRanges)
 }
 
 // RemoveSubnetRule removes a subnet from the proxy handler

netstack2/tun.go

@@ -350,10 +350,10 @@ func (net *Net) ListenUDP(laddr *net.UDPAddr) (*gonet.UDPConn, error) {
 
 // AddProxySubnetRule adds a subnet rule to the proxy handler
 // If portRanges is nil or empty, all ports are allowed for this subnet
-func (net *Net) AddProxySubnetRule(sourcePrefix, destPrefix netip.Prefix, portRanges []PortRange) {
+func (net *Net) AddProxySubnetRule(sourcePrefix, destPrefix, rewriteTo netip.Prefix, portRanges []PortRange) {
 	tun := (*netTun)(net)
 	if tun.proxyHandler != nil {
-		tun.proxyHandler.AddSubnetRule(sourcePrefix, destPrefix, portRanges)
+		tun.proxyHandler.AddSubnetRule(sourcePrefix, destPrefix, rewriteTo, portRanges)
 	}
 }