Golang tcp 轉發

第一版本

accept獲取的Conn里的localAddr做為源地址，remoteAddr來做為目的地址

// tcpForward package mainimport ("fmt""net""os" )func TcpForward(port int) {lisPort := fmt.Sprint(":", port)listen, err := net.Listen("tcp", lisPort)if err != nil {fmt.Println("fault to listen,err: %s", err.Error())os.Exit(1)}defer listen.Close()fmt.Println("listenning now!")for {fromConn, err := listen.Accept()if err != nil {fmt.Println("fault,err: %s", err.Error())fromConn.Close()continue}go toDial(fromConn)}}func toDial(fromConn net.Conn) {toAddr := fromConn.RemoteAddr()toConn, err := net.Dial("tcp", toAddr.String())if err != nil {fmt.Println("fault,err: %s", err.Error())toConn.Close()}fmt.Println("%s to %s", fromConn.LocalAddr().String(), toConn.RemoteAddr().String())go copy(fromConn, toConn, 512)go copy(toConn, fromConn, 512) }func copy(f, t net.Conn, n int) {defer f.Close()defer t.Close()var buf = make([]byte, n)for {count, err := f.Read(buf)if err != nil {fmt.Println("fault,err: %s", err.Error())break}count, err = t.Write(buf[:count])if err != nil {fmt.Println("fault,err: %s", err.Error())break}} }

win設置代理，用edge訪問網頁報錯！！！

報錯信息：

C:/Go/bin/go.exe build [C:/Users/imcjb/Desktop/egoweb] 成功: 進程退出代碼 0. C:/Users/imcjb/Desktop/egoweb/egoweb.exe [C:/Users/imcjb/Desktop/egoweb] Hello World! C:\Users\imcjb\Desktop\egoweb\egoweb.exe listenning now! fault,err: %s dial tcp 127.0.0.1:53391: connectex: No connection could be made because the target machine actively refused it. panic: runtime error: invalid memory address or nil pointer dereference [signal 0xc0000005 code=0x0 addr=0x18 pc=0x6154cf]goroutine 20 [running]: main.toDial(0x6f4a20, 0xc000092038)C:/Users/imcjb/Desktop/egoweb/tcpForward.go:36 +0x3bf created by main.TcpForwardC:/Users/imcjb/Desktop/egoweb/tcpForward.go:26 +0x2db fault,err: %s dial tcp 127.0.0.1:53392: connectex: No connection could be made because the target machine actively refused it. panic: runtime error: invalid memory address or nil pointer dereference [signal 0xc0000005 code=0x0 addr=0x18 pc=0x6154cf]goroutine 19 [running]: main.toDial(0x6f4a20, 0xc000092030)C:/Users/imcjb/Desktop/egoweb/tcpForward.go:36 +0x3bf created by main.TcpForwardC:/Users/imcjb/Desktop/egoweb/tcpForward.go:26 +0x2db 錯誤: 進程退出代碼 2.

錯誤猜測

這里的remoteaddr返回的其實是轉發前的真實ip，而非目的ip

代碼部分還有一個小問題println、sprintf使用錯誤，他們的參數是interface{}

轉載于:https://www.cnblogs.com/boxker/p/11041049.html

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