新增加密udp工具类

commonutil/udp.go

@@ -0,0 +1,93 @@
+package commonutil
+
+import (
+	"bytes"
+	"encoding/binary"
+	"net"
+	"time"
+)
+
+//
+type UdpClient struct {
+	Local   string
+	Connect *net.UDPConn
+	BufSize int
+}
+
+//指令
+const (
+	OP_NOOP = byte(iota)
+	OP_JOIN
+	OP_BYE
+	OP_SAY_ONLINE
+	OP_TYPE_DATA
+	OP_GET_DOWNLOADERCODE     //上报下载器代码
+	OP_WILLCHANGEIP           //将要切换IP
+	OP_PUSH_DOWNLOADERCODES   //
+	OP_DELETE_DOWNLOADERCODES //需要删除
+	OP_NEWCLIENT              //下载器重新链接
+)
+
+//
+func (c *UdpClient) Listen(fn func(byte, []byte, *net.UDPAddr)) {
+	listenAddr, _ := net.ResolveUDPAddr("udp4", c.Local)
+	c.Connect, _ = net.ListenUDP("udp4", listenAddr)
+	go c.readUdp(fn)
+}
+
+//写
+func (c *UdpClient) WriteUdp(data []byte /*写入数据*/, act byte /*动作*/, toaddr *net.UDPAddr /*目标端地址*/) error {
+	bs := make([]byte, 1)
+	bs[0] = act
+	sizebs := Int2Byte(int32(len(data)))
+	bs = append(bs, sizebs...)
+	bs = append(bs, data...)
+	if len(bs) > c.BufSize {
+		bs = bs[:c.BufSize]
+	} else if len(bs) < c.BufSize {
+		bs = append(bs, bytes.Repeat([]byte{0}, c.BufSize-len(bs))...)
+	}
+	for i := 0; i < 5; i++ { //尝试5次
+		_, err := c.Connect.WriteToUDP(bs, toaddr)
+		if err == nil {
+			break
+		}
+		time.Sleep(1 * time.Second)
+	}
+	return nil
+}
+
+//读
+func (c *UdpClient) readUdp(fn func(byte, []byte, *net.UDPAddr)) {
+	for {
+		head := make([]byte, c.BufSize)
+		n, ra, err := c.Connect.ReadFromUDP(head)
+		if err != nil || n == 0 { //取不到数据
+			time.Sleep(1 * time.Second)
+			continue
+		}
+		size := int(Byte2Int(head[1:5]))
+		if size < 1 { //无数据，仅仅是控制指令
+			go fn(head[0], []byte{}, ra)
+		} else {
+			if size > c.BufSize-5 {
+				size = c.BufSize - 5
+			}
+			go fn(head[0], head[5:5+size], ra)
+		}
+	}
+}
+
+//
+func Byte2Int(src []byte) int32 {
+	var ret int32
+	binary.Read(bytes.NewReader(src), binary.BigEndian, &ret)
+	return ret
+}
+
+//
+func Int2Byte(src int32) []byte {
+	buf := bytes.NewBuffer([]byte{})
+	binary.Write(buf, binary.BigEndian, src)
+	return buf.Bytes()
+}