golang实现ping

以下是使用Golang实现ping的示例代码：

package main

import (
    "fmt"
    "net"
    "os"
    "time"
)

func main() {
    if len(os.Args) != 2 {
        fmt.Println("Usage: go run ping.go <host>")
        os.Exit(1)
    }

    host := os.Args[1]
    addr, err := net.ResolveIPAddr("ip4", host)
    if err != nil {
        fmt.Println("Error resolving host:", err)
        os.Exit(1)
    }

    conn, err := net.DialIP("ip4:icmp", nil, addr)
    if err != nil {
        fmt.Println("Error connecting to host:", err)
        os.Exit(1)
    }

    defer conn.Close()

    seq := 1
    for {
        start := time.Now()

        msg := make([]byte, 64)
        msg[0] = 8 // echo
        msg[1] = 0 // code
        msg[2] = 0 // checksum
        msg[3] = 0 // checksum
        msg[4] = byte(seq) // identifier
        msg[5] = 0 // identifier
        msg[6] = 0 // sequence number
        msg[7] = 0 // sequence number

        check := checkSum(msg)
        msg[2] = byte(check >> 8)
        msg[3] = byte(check & 255)

        conn.SetDeadline(time.Now().Add(time.Second))

        _, err := conn.Write(msg)
        if err != nil {
            fmt.Println("Error sending ping:", err)
            os.Exit(1)
        }

        reply := make([]byte, 64)
        _, err = conn.Read(reply)
        if err != nil {
            fmt.Println("Error receiving ping reply:", err)
            os.Exit(1)
        }

        elapsed := time.Since(start)
        fmt.Printf("Ping reply from %s seq=%d time=%v\n", addr.String(), seq, elapsed)

        time.Sleep(time.Second)
        seq++
    }
}

func checkSum(msg []byte) uint16 {
    sum := uint32(0)
    for i := 0; i < len(msg)-1; i += 2 {
        sum += uint32(msg[i+1])<<8 | uint32(msg[i])
    }
    if len(msg)%2 == 1 {
        sum += uint32(msg[len(msg)-1])
    }
    sum = (sum >> 16) + (sum & 0xffff)
    sum += sum >> 16
    return ^uint16(sum)
}

该程序实现了使用ICMP协议向指定主机发送ping并接收回复。程序首先解析传入的主机名，然后使用DialIP函数连接到主机。在循环中，程序构造一个ICMP消息并发送到主机，然后等待主机的回复。程序在每次收到回复时计算延迟并打印出来，然后等待一秒钟并发送下一个ping。checkSum函数用于计算ICMP消息的校验和。