Feature: support outbound socks5 udp

adapters/outbound/util.go

@@ -1,13 +1,16 @@
 package adapters
 
 import (
+	"bytes"
 	"crypto/tls"
 	"fmt"
 	"net"
 	"net/url"
+	"strconv"
 	"sync"
 	"time"
 
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
 )
 
@@ -60,3 +63,36 @@ func getClientSessionCache() tls.ClientSessionCache {
 	})
 	return globalClientSessionCache
 }
+
+func serializesSocksAddr(metadata *C.Metadata) []byte {
+	var buf [][]byte
+	aType := uint8(metadata.AddrType)
+	p, _ := strconv.Atoi(metadata.Port)
+	port := []byte{uint8(p >> 8), uint8(p & 0xff)}
+	switch metadata.AddrType {
+	case socks5.AtypDomainName:
+		len := uint8(len(metadata.Host))
+		host := []byte(metadata.Host)
+		buf = [][]byte{{aType, len}, host, port}
+	case socks5.AtypIPv4:
+		host := metadata.IP.To4()
+		buf = [][]byte{{aType}, host, port}
+	case socks5.AtypIPv6:
+		host := metadata.IP.To16()
+		buf = [][]byte{{aType}, host, port}
+	}
+	return bytes.Join(buf, nil)
+}
+
+type fakeUDPConn struct {
+	net.Conn
+}
+
+func (fuc *fakeUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	return fuc.Conn.Write(b)
+}
+
+func (fuc *fakeUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	n, err := fuc.Conn.Read(b)
+	return n, fuc.RemoteAddr(), err
+}