Implement WireGuard protocol as outbound (client) (#1344)

* implement WireGuard protocol for Outbound

* upload license

* fix build for openbsd & dragonfly os

* updated wireguard-go

* fix up

* switch to another wireguard fork

* fix

* switch to upstream

* open connection through internet.Dialer (#1)

* use internet.Dialer

* maybe better code

* fix

* real fix

Co-authored-by: nanoda0523 <nanoda0523@users.noreply.github.com>

* fix bugs & add ability to recover during connection reset on UDP over TCP parent protocols

* improve performance

improve performance

* dns lookup endpoint && remove unused code

* interface address fallback

* better code && add config test case

Co-authored-by: nanoda0523 <nanoda0523@users.noreply.github.com>

infra/conf/wireguard.go

@@ -0,0 +1,111 @@
+package conf
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/xtls/xray-core/proxy/wireguard"
+)
+
+type WireGuardPeerConfig struct {
+	PublicKey    string   `json:"publicKey"`
+	PreSharedKey string   `json:"preSharedKey"`
+	Endpoint     string   `json:"endpoint"`
+	KeepAlive    int      `json:"keepAlive"`
+	AllowedIPs   []string `json:"allowedIPs,omitempty"`
+}
+
+func (c *WireGuardPeerConfig) Build() (proto.Message, error) {
+	var err error
+	config := new(wireguard.PeerConfig)
+
+	config.PublicKey, err = parseWireGuardKey(c.PublicKey)
+	if err != nil {
+		return nil, err
+	}
+
+	if c.PreSharedKey != "" {
+		config.PreSharedKey, err = parseWireGuardKey(c.PreSharedKey)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		config.PreSharedKey = "0000000000000000000000000000000000000000000000000000000000000000"
+	}
+
+	config.Endpoint = c.Endpoint
+	// default 0
+	config.KeepAlive = int32(c.KeepAlive)
+	if c.AllowedIPs == nil {
+		config.AllowedIps = []string{"0.0.0.0/0", "::0/0"}
+	} else {
+		config.AllowedIps = c.AllowedIPs
+	}
+
+	return config, nil
+}
+
+type WireGuardConfig struct {
+	SecretKey  string                 `json:"secretKey"`
+	Address    []string               `json:"address"`
+	Peers      []*WireGuardPeerConfig `json:"peers"`
+	MTU        int                    `json:"mtu"`
+	NumWorkers int                    `json:"workers"`
+}
+
+func (c *WireGuardConfig) Build() (proto.Message, error) {
+	config := new(wireguard.DeviceConfig)
+
+	var err error
+	config.SecretKey, err = parseWireGuardKey(c.SecretKey)
+	if err != nil {
+		return nil, err
+	}
+
+	if c.Address == nil {
+		// bogon ips
+		config.Endpoint = []string{"10.0.0.1", "fd59:7153:2388:b5fd:0000:0000:0000:0001"}
+	} else {
+		config.Endpoint = c.Address
+	}
+
+	if c.Peers != nil {
+		config.Peers = make([]*wireguard.PeerConfig, len(c.Peers))
+		for i, p := range c.Peers {
+			msg, err := p.Build()
+			if err != nil {
+				return nil, err
+			}
+			config.Peers[i] = msg.(*wireguard.PeerConfig)
+		}
+	}
+
+	if c.MTU == 0 {
+		config.Mtu = 1420
+	} else {
+		config.Mtu = int32(c.MTU)
+	}
+	// these a fallback code exists in github.com/nanoda0523/wireguard-go code,
+	// we don't need to process fallback manually
+	config.NumWorkers = int32(c.NumWorkers)
+
+	return config, nil
+}
+
+func parseWireGuardKey(str string) (string, error) {
+	if len(str) != 64 {
+		// may in base64 form
+		dat, err := base64.StdEncoding.DecodeString(str)
+		if err != nil {
+			return "", err
+		}
+		if len(dat) != 32 {
+			return "", newError("key should be 32 bytes: " + str)
+		}
+		return hex.EncodeToString(dat), err
+	} else {
+		// already hex form
+		return str, nil
+	}
+}