Merge pull request #36 from wiretrustee/avoid-proxy-when-local-net

feature: initial implementation of avoiding local proxy if peers are …

connection/connection.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	ice "github.com/pion/ice/v2"
 	log "github.com/sirupsen/logrus"
+	"github.com/wiretrustee/wiretrustee/iface"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 	"sync"
 	"time"
@@ -93,6 +94,7 @@ func (conn *Connection) Open(timeout time.Duration) error {
 
 	// create an ice.Agent that will be responsible for negotiating and establishing actual peer-to-peer connection
 	a, err := ice.NewAgent(&ice.AgentConfig{
+		// MulticastDNSMode: ice.MulticastDNSModeQueryAndGather,
 		NetworkTypes: []ice.NetworkType{ice.NetworkTypeUDP4},
 		Urls:         conn.Config.StunTurnURLS,
 		InterfaceFilter: func(s string) bool {
@@ -144,10 +146,23 @@ func (conn *Connection) Open(timeout time.Duration) error {
 			return err
 		}
 
-		err = conn.wgProxy.Start(remoteConn)
+		pair, err := conn.agent.GetSelectedCandidatePair()
 		if err != nil {
 			return err
 		}
+		// in case the remote peer is in the local network we don't need a Wireguard proxy, direct communication is possible.
+		if pair.Local.Type() == ice.CandidateTypeHost && pair.Remote.Type() == ice.CandidateTypeHost {
+			log.Debugf("remote peer %s is in the local network with an address %s", conn.Config.RemoteWgKey.String(), pair.Remote.Address())
+			err = conn.wgProxy.StartLocal(fmt.Sprintf("%s:%d", pair.Remote.Address(), iface.WgPort))
+			if err != nil {
+				return err
+			}
+		} else {
+			err = conn.wgProxy.Start(remoteConn)
+			if err != nil {
+				return err
+			}
+		}
 
 		log.Infof("opened connection to peer %s", conn.Config.RemoteWgKey.String())
 	case <-time.After(timeout):
@@ -298,7 +313,6 @@ func (conn *Connection) listenOnConnectionStateChanges() error {
 			}
 			log.Infof("will connect to peer %s via a selected connnection candidate pair %s", conn.Config.RemoteWgKey.String(), pair)
 		} else if state == ice.ConnectionStateDisconnected || state == ice.ConnectionStateFailed {
-			// todo do we really wanna have a connection restart within connection itself? Think of moving it outside
 			err := conn.Close()
 			if err != nil {
 				log.Warnf("error while closing connection to peer %s -> %s", conn.Config.RemoteWgKey.String(), err.Error())

connection/wgproxy.go

@@ -42,6 +42,15 @@ func (p *WgProxy) Close() error {
 	return nil
 }
 
+func (p *WgProxy) StartLocal(host string) error {
+	err := iface.UpdatePeer(p.iface, p.remoteKey, p.allowedIps, DefaultWgKeepAlive, host)
+	if err != nil {
+		log.Errorf("error while configuring Wireguard peer [%s] %s", p.remoteKey, err.Error())
+		return err
+	}
+	return nil
+}
+
 // Start starts a new proxy using the ICE connection
 func (p *WgProxy) Start(remoteConn *ice.Conn) error {
 

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/vishvananda/netlink v1.1.0
 	github.com/vishvananda/netns v0.0.0-20191106174202-0a2b9b5464df
 	golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf
+	golang.org/x/sys v0.0.0-20210510120138-977fb7262007
 	golang.zx2c4.com/wireguard v0.0.0-20210604143328-f9b48a961cd2
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20210506160403-92e472f520a5
 	golang.zx2c4.com/wireguard/windows v0.3.14

iface/iface.go

@@ -1,27 +1,25 @@
 package iface
 
 import (
-	"net"
-	"time"
-
 	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/device"
 	"golang.zx2c4.com/wireguard/tun"
 	"golang.zx2c4.com/wireguard/wgctrl"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+	"net"
+	"time"
 )
 
 const (
 	defaultMTU = 1280
+	WgPort     = 51820
 )
 
-// Saves tun device object - is it required?
 var tunIface tun.Device
 
-// Create Creates a new Wireguard interface, sets a given IP and brings it up.
-// Will reuse an existing one.
-func Create(iface string, address string) error {
+// CreateWithUserspace Creates a new Wireguard interface, using wireguard-go userspace implementation
+func CreateWithUserspace(iface string, address string) error {
 	var err error
 	tunIface, err = tun.CreateTUN(iface, defaultMTU)
 	if err != nil {
@@ -52,7 +50,7 @@ func Create(iface string, address string) error {
 
 	log.Debugln("UAPI listener started")
 
-	err = assignAddr(address, tunIface)
+	err = assignAddr(address, iface)
 	if err != nil {
 		return err
 	}
@@ -85,10 +83,12 @@ func Configure(iface string, privateKey string) error {
 		return err
 	}
 	fwmark := 0
+	p := WgPort
 	cfg := wgtypes.Config{
 		PrivateKey:   &key,
 		ReplacePeers: false,
 		FirewallMark: &fwmark,
+		ListenPort:   &p,
 	}
 	err = wg.ConfigureDevice(iface, cfg)
 	if err != nil {

iface/iface_darwin.go

@@ -2,19 +2,18 @@ package iface
 
 import (
 	log "github.com/sirupsen/logrus"
-	"golang.zx2c4.com/wireguard/tun"
 	"net"
 	"os/exec"
 	"strings"
 )
 
-//const (
-//	interfacePrefix = "utun"
-//)
+// Create Creates a new Wireguard interface, sets a given IP and brings it up.
+func Create(iface string, address string) error {
+	return CreateWithUserspace(iface, address)
+}
 
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided
-func assignAddr(address string, tunDevice tun.Device) error {
-	ifaceName, err := tunDevice.Name()
+func assignAddr(address string, ifaceName string) error {
 	ip := strings.Split(address, "/")
 	cmd := exec.Command("ifconfig", ifaceName, "inet", address, ip[0])
 	if out, err := cmd.CombinedOutput(); err != nil {

iface/iface_linux.go

@@ -3,24 +3,76 @@ package iface
 import (
 	log "github.com/sirupsen/logrus"
 	"github.com/vishvananda/netlink"
-	"golang.zx2c4.com/wireguard/tun"
-
 	"os"
 )
 
-//const (
-//	interfacePrefix = "wg"
-//)
+// Create Creates a new Wireguard interface, sets a given IP and brings it up.
+// Will reuse an existing one.
+func Create(iface string, address string) error {
 
-// assignAddr Adds IP address to the tunnel interface
-func assignAddr(address string, tunDevice tun.Device) error {
-	var err error
+	if WireguardModExists() {
+		log.Debug("using kernel Wireguard module")
+		return CreateWithKernel(iface, address)
+	} else {
+		return CreateWithUserspace(iface, address)
+	}
+}
+
+// CreateWithKernel Creates a new Wireguard interface using kernel Wireguard module.
+// Works for Linux and offers much better network performance
+func CreateWithKernel(iface string, address string) error {
 	attrs := netlink.NewLinkAttrs()
-	attrs.Name, err = tunDevice.Name()
+	attrs.Name = iface
+
+	link := wgLink{
+		attrs: &attrs,
+	}
+
+	log.Debugf("adding device: %s", iface)
+	err := netlink.LinkAdd(&link)
+	if os.IsExist(err) {
+		log.Infof("interface %s already exists. Will reuse.", iface)
+	} else if err != nil {
+		return err
+	}
+
+	log.Debugf("adding address %s to interface: %s", address, iface)
+	addr, _ := netlink.ParseAddr(address)
+	err = netlink.AddrAdd(&link, addr)
+	if os.IsExist(err) {
+		log.Infof("interface %s already has the address: %s", iface, address)
+	} else if err != nil {
+		return err
+	}
+	err = assignAddr(address, iface)
 	if err != nil {
 		return err
 	}
 
+	// todo do a discovery
+	log.Debugf("setting MTU: %s", iface)
+	err = netlink.LinkSetMTU(&link, defaultMTU)
+	if err != nil {
+		log.Errorf("error setting MTU on interface: %s", iface)
+		return err
+	}
+
+	log.Debugf("bringing up interface: %s", iface)
+	err = netlink.LinkSetUp(&link)
+	if err != nil {
+		log.Errorf("error bringing up interface: %s", iface)
+		return err
+	}
+
+	return nil
+}
+
+// assignAddr Adds IP address to the tunnel interface
+func assignAddr(address, name string) error {
+	var err error
+	attrs := netlink.NewLinkAttrs()
+	attrs.Name = name
+
 	link := wgLink{
 		attrs: &attrs,
 	}

iface/iface_windows.go

@@ -8,16 +8,21 @@ import (
 	"net"
 )
 
+// Create Creates a new Wireguard interface, sets a given IP and brings it up.
+func Create(iface string, address string) error {
+	return CreateWithUserspace(iface, address)
+}
+
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided
-func assignAddr(address string, tunDevice tun.Device) error {
-	ifaceName, err := tunDevice.Name()
-	nativeTunDevice := tunDevice.(*tun.NativeTun)
+func assignAddr(address string, ifaceName string) error {
+
+	nativeTunDevice := tunIface.(*tun.NativeTun)
 	luid := winipcfg.LUID(nativeTunDevice.LUID())
 
 	ip, ipnet, _ := net.ParseCIDR(address)
 
 	log.Debugf("adding address %s to interface: %s", address, ifaceName)
-	err = luid.SetIPAddresses([]net.IPNet{{ip, ipnet.Mask}})
+	err := luid.SetIPAddresses([]net.IPNet{{ip, ipnet.Mask}})
 	if err != nil {
 		return err
 	}

iface/mod.go

@@ -0,0 +1,144 @@
+// +build linux
+
+package iface
+
+// Holds logic to check existence of Wireguard kernel module
+// Copied from https://github.com/paultag/go-modprobe
+
+import (
+	"debug/elf"
+	"fmt"
+	"golang.org/x/sys/unix"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var (
+	// get the root directory for the kernel modules. If this line panics,
+	// it's because getModuleRoot has failed to get the uname of the running
+	// kernel (likely a non-POSIX system, but maybe a broken kernel?)
+	moduleRoot = getModuleRoot()
+)
+
+// Get the module root (/lib/modules/$(uname -r)/)
+func getModuleRoot() string {
+	uname := unix.Utsname{}
+	if err := unix.Uname(&uname); err != nil {
+		panic(err)
+	}
+
+	i := 0
+	for ; uname.Release[i] != 0; i++ {
+	}
+
+	return filepath.Join(
+		"/lib/modules",
+		string(uname.Release[:i]),
+	)
+}
+
+// modName will, given a file descriptor to a Kernel Module (.ko file), parse the
+// binary to get the module name. For instance, given a handle to the file at
+// `kernel/drivers/usb/gadget/legacy/g_ether.ko`, return `g_ether`.
+func modName(file *os.File) (string, error) {
+	f, err := elf.NewFile(file)
+	if err != nil {
+		return "", err
+	}
+
+	syms, err := f.Symbols()
+	if err != nil {
+		return "", err
+	}
+
+	for _, sym := range syms {
+		if strings.Compare(sym.Name, "__this_module") == 0 {
+			section := f.Sections[sym.Section]
+			data, err := section.Data()
+			if err != nil {
+				return "", err
+			}
+
+			if len(data) < 25 {
+				return "", fmt.Errorf("modprobe: data is short, __this_module is '%s'", data)
+			}
+
+			data = data[24:]
+			i := 0
+			for ; data[i] != 0x00; i++ {
+			}
+			return string(data[:i]), nil
+		}
+	}
+
+	return "", fmt.Errorf("No name found. Is this a .ko or just an ELF?")
+}
+
+// Open every single kernel module under the root, and parse the ELF headers to
+// extract the module name.
+func elfMap(root string) (map[string]string, error) {
+	ret := map[string]string{}
+
+	err := filepath.Walk(
+		root,
+		func(path string, info os.FileInfo, err error) error {
+
+			if err != nil {
+				// skip broken files
+				return nil
+			}
+
+			if !info.Mode().IsRegular() {
+				return nil
+			}
+			fd, err := os.Open(path)
+			if err != nil {
+				return err
+			}
+			defer fd.Close()
+			name, err := modName(fd)
+			if err != nil {
+				/* For now, let's just ignore that and avoid adding to it */
+				return nil
+			}
+
+			ret[name] = path
+			return nil
+		})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}
+
+// Open every single kernel module under the kernel module directory
+// (/lib/modules/$(uname -r)/), and parse the ELF headers to extract the
+// module name.
+func generateMap() (map[string]string, error) {
+	return elfMap(moduleRoot)
+}
+
+// WireguardModExists returns true if Wireguard kernel module exists.
+func WireguardModExists() bool {
+	_, err := resolveModName("wireguard")
+	return err == nil
+}
+
+// resolveModName will, given a module name (such as `wireguard`) return an absolute
+// path to the .ko that provides that module.
+func resolveModName(name string) (string, error) {
+	paths, err := generateMap()
+	if err != nil {
+		return "", err
+	}
+
+	fsPath := paths[name]
+	if !strings.HasPrefix(fsPath, moduleRoot) {
+		return "", fmt.Errorf("module isn't in the module directory")
+	}
+
+	return fsPath, nil
+}