WIP working ipv4/ipv6 forward

1 files changed, 105 insertions, 31 deletions

diff --git a/tunnel/tools/libwg-go/api-android.go b/tunnel/tools/libwg-go/api-android.go
index 4e3724ad..dedbdca4 100644
--- a/tunnel/tools/libwg-go/api-android.go
+++ b/tunnel/tools/libwg-go/api-android.go
@@ -18,6 +18,7 @@ import (
 	"os/signal"
 	"runtime"
 	"runtime/debug"
+	"sort"
 	"strings"
 	"unsafe"
 
@@ -27,10 +28,9 @@ import (
 	"github.com/insomniacslk/dhcp/iana"
 
 	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/link/fdbased"
-	"gvisor.dev/gvisor/pkg/tcpip/link/rawfile"
 	"gvisor.dev/gvisor/pkg/tcpip/link/sniffer"
-	tunlink "gvisor.dev/gvisor/pkg/tcpip/link/tun"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
@@ -69,6 +69,8 @@ type TunnelHandle struct {
 	stack  *stack.Stack
 	tnet   *netstack.Net
 	logger *device.Logger
+	interfaceName string
+	tunFd  int
 }
 
 var tunnelHandles map[int32]TunnelHandle
@@ -107,6 +109,9 @@ func wgTurnOn(interfaceName string, tunFd int32, settings string) int32 {
 		return -1
 	}
 
+	handle.interfaceName = interfaceName
+	handle.tunFd = int(tunFd)
+
 	name := "foobar"
 	logger.Verbosef("Attaching to interface %v", name)
 	device := device.NewDevice(tun, conn.NewStdNetBind(), logger)
@@ -275,6 +280,15 @@ func NewDHCPv4Query(flags uint32, modifiers ...dhcpv6.Modifier) (*dhcpv6.Message
 	return msg, nil
 }
 
+func parseIP(s string) tcpip.Address {
+        addr := tcpip.Address(net.ParseIP(s))
+        ip4addr := addr.To4(); if ip4addr != "" {
+                return ip4addr
+        } else {
+                return addr
+        }
+}
+
 func newTunnel(logger *device.Logger) (TunnelHandle, tun.Device, error) {
 	// TODO: Configurable local address
 	localAddresses := []net.IP{net.ParseIP("fe80::104")}
@@ -402,64 +416,124 @@ func (handle *TunnelHandle) startDHCPv6() {
 	}
 	ack := msgOpt.(*dhcpv6.OptDHCPv4Msg).Msg
 
+	handle.logger.Verbosef("DHCP done")
+
+	var nic tcpip.NICID = 2
+	handle.createNetTUNFromFD(nic)
+
 	// TODO: Close clients?
 	//	client.Close()
 	handle.logger.Verbosef("doClient end %v %v", ack.YourIPAddr, ack.SubnetMask())
-	if ip4 := ack.YourIPAddr.To4(); ip4 == nil {
-		handle.logger.Errorf("Not IPv4! %v", ack.YourIPAddr)
-		return
+	if ip4 := ack.YourIPAddr.To4(); ip4 != nil {
+		handle.logger.Errorf("IPv4! %v", ack.YourIPAddr)
+
+		addr := tcpip.Address(ack.YourIPAddr)
+		subnet, err := tcpip.NewSubnet(
+			addr,
+			tcpip.AddressMask(parseIP("255.255.255.255")))
+		if err != nil {
+			handle.logger.Errorf("NewSubnet: %v", err)
+			return
+		}
+
+		// The TUN interface need a link address for some reason
+		linkAddr := tcpip.Address(parseIP("169.254.0.1"))
+		tcperr := handle.stack.AddAddress(nic, ipv4.ProtocolNumber, linkAddr)
+		if tcperr != nil {
+			handle.logger.Errorf("AddAddress: %v", tcperr)
+			return
+		}
+
+		handle.stack.AddRoute(tcpip.Route{
+			Destination: subnet,
+			NIC: nic,
+		})
+		handle.stack.AddRoute(tcpip.Route{
+			Destination: header.IPv4EmptySubnet,
+			NIC: 1,
+		})
 	}
 
 	// tcperr := tnet.AddAddress(ack.YourIPAddr); if tcperr != nil {
 	//	 log.Fatal(tcperr)
 	// }
 
+	// Maybe
+	// The TUN interface need a link address for some reason
+	linkAddr := tcpip.Address(parseIP("fe80::104"))
+	tcperr := handle.stack.AddAddress(nic, ipv6.ProtocolNumber, linkAddr)
+	if tcperr != nil {
+		handle.logger.Errorf("AddAddress: %v", tcperr)
+		return
+	}
+
+	handle.stack.AddRoute(tcpip.Route{
+		Destination: header.IPv6EmptySubnet,
+		NIC: 1,
+	})
+
 	iana := msg.GetOneOption(dhcpv6.OptionIANA).(*dhcpv6.OptIANA)
 	for _, addr := range iana.Options.Get(dhcpv6.OptionIAAddr) {
 		ip := addr.(*dhcpv6.OptIAAddress).IPv6Addr
 		str := ip.String() + "/128"
 		handle.logger.Verbosef("Addr %v", str)
 
-		// err := tnet.AddAddress(ip); if err != nil {
-		// 	log.Fatal(err)
-		// }
+		addr := tcpip.Address(ip)
+		subnet, err := tcpip.NewSubnet(
+			addr,
+			tcpip.AddressMask(parseIP("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")))
+		if err != nil {
+			handle.logger.Errorf("NewSubnet: %v", err)
+			return
+		}
+
+		handle.stack.AddRoute(tcpip.Route{
+			Destination: subnet,
+			NIC: nic,
+		})
 	}
 
-	handle.logger.Verbosef("DHCP done")
-}
+        // Sort route table for longest prefix match
+        routes := handle.stack.GetRouteTable()
+        sort.Slice(routes, func(i, j int) bool {
+		return routes[i].Destination.Prefix() > routes[j].Destination.Prefix()
+	})
+        handle.stack.SetRouteTable(routes)
 
-func (handle *TunnelHandle) newTun(id tcpip.NICID, tunName string) {
-        mtu, err := rawfile.GetMTU(tunName)
-	if err != nil {
-		handle.logger.Errorf("GetMTU: %v", err)
-		return
-	}
+        handle.stack.SetForwarding(ipv4.ProtocolNumber, true)
+        handle.stack.SetForwarding(ipv6.ProtocolNumber, true)
+	handle.logger.Verbosef("DHCP addresses set up")
+	// TODO update WireGuard settings
+}
 
-	fd, err := tunlink.Open(tunName)
+func (handle *TunnelHandle) newTun(nic tcpip.NICID) error {
+	err := unix.SetNonblock(handle.tunFd, true)
 	if err != nil {
-		handle.logger.Errorf("Open: %v", err)
-		return
+		return err
 	}
 
-	linkEP, err := fdbased.New(&fdbased.Options{FDs: []int{fd}, MTU: mtu})
+	var mtu uint32 = 1420
+	linkEP, err := fdbased.New(&fdbased.Options{FDs: []int{handle.tunFd}, MTU: mtu})
 	if err != nil {
 		handle.logger.Errorf("fdbased.New: %v", err)
-		return
+		return err
 	}
-	if err := handle.stack.CreateNIC(id, sniffer.New(linkEP)); err != nil {
+
+	if err := handle.stack.CreateNIC(nic, sniffer.New(linkEP)); err != nil {
 		handle.logger.Errorf("CreateNIC: %v", err)
-		return
+		// TODO: Return error
+		return nil
 	}
+
+	return nil
 }
 
-func (handle *TunnelHandle) createNetTUNFromFD(tunFd int) {
-	// newTun(2, "tun0")
-	// tun, name, err := handle.createNetTUNFromFD(int(tunFd))
-	// if err != nil {
-	// 	unix.Close(int(tunFd))
-	// 	logger.Errorf("createNetTUNFromFD: %v", err)
-	// 	return -1
-	// }
+func (handle *TunnelHandle) createNetTUNFromFD(nic tcpip.NICID) {
+	err := handle.newTun(nic)
+	if err != nil {
+		handle.logger.Errorf("newTun: %v", err)
+		return
+	}
 }
 
 func main() {}