第一版本
accept获取的Conn里的localAddr做为源地址，remoteAddr来做为目的地址
// 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设置代理，用edge访问网页报错！！！
报错信息：
C:/Go/bin/go.exe build [C:/Users/imcjb/Desktop/egoweb]
成功: 进程退出代码 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
错误: 进程退出代码 2.
错误猜测
这里的remoteaddr返回的其实是转发前的真实ip，而非目的ip
代码部分还有一个小问题println、sprintf使用错误，他们的参数是interface{}