GO语言练习：网络编程 ICMP 示例

1、代码

2、编译及运行

---

1、Go语言网络编程：ICMP示例代码 icmptest.go

 package main

 import (
     "fmt"
     "net"
     "os"
     "io"
     "bytes"
 )

 func main() {
     if len(os.Args) !=  {
         fmt.Println("Usage : ", os.Args[], "host")
         os.Exit()
     }
     service := os.Args[]

     conn, err := net.Dial("ip4:icmp", service)
     checkError(err)

     var msg []byte
     msg[] =
     msg[] =
     msg[] =
     msg[] =
     msg[] =
     msg[] =
     msg[] =
     msg[] =
     len :=
     check := checkSum(msg[:len])
     msg[] = byte(check >> )
     msg[] = byte(check & )

     _, err = conn.Write(msg[:len])
     checkError(err)

     fmt.Println("Got response")
     if msg[] ==  {
         fmt.Println("Identifier matches")
     }
     if msg[] ==  {
         fmt.Println("Sequence matches")
     }

     os.Exit()
 }

 func checkSum(msg []byte) uint16 {
     sum := 

     for n := ; n < len(msg) - ; n +=  {
         sum += int(msg[n]) *  + int(msg[n+])
     }
     sum = (sum >>  ) + (sum & 0xffff)
     sum += (sum >> )
     var answer uint16 = uint16(^sum)
     return answer
 }

 func checkError(err error) {
     if err != nil {
         fmt.Fprintf(os.Stderr, "Fatal error : %s\n", err.Error())
         os.Exit()
     }
 }

 func readFully(conn net.Conn) ([]byte, error) {
     defer conn.Close()

     result := bytes.NewBuffer(nil)
     var buf []byte
     for {
         n, err := conn.Read(buf[:])
         result.Write(buf[:n])
         if err != nil {
             if err == io.EOF {
                 break
             }
             return nil, err
         }
     }

     return result.Bytes(), nil
 }

2、编译及运行

$ go build icmptest.go
$ ls
icmptest  icmptest.go
$ ./icmptest www.baidu.com
Got response
Identifier matches
Sequence matches