socket.AF_INET, socket.SOCK_RAW, socket.getprotobyname("icmp")

这段代码使用Python中的socket模块创建了一个原始套接字，用于发送ICMP数据包[^1]。其中，AF_INET是指使用IPv4地址族，SOCK_RAW是指使用原始套接字，getprotobyname("icmp")是获取ICMP协议的编号。这种类型的套接字可以让应用程序访问底层通信协议，从而实现原始数据包的发送和接收。

如果想要测试在你的操作系统下是否支持某个socket类型，可以使用C语言中的socket函数。下面是一个例子，它使用socket函数创建一个SOCK_RDM类型的socket，并返回socket描述符。如果创建失败，程序会输出错误信息。在Linux系统下，SOCK_RDM已经废弃，因此程序运行时会输出"Protocol not supported"的错误信息[^2]。

#include <stdio.h>
#include <sys/socket.h>

int main() {
    int sock_fd = socket(AF_INET, SOCK_RDM, 0);
    if (sock_fd == -1) {
        perror("socket: ");
    } else {
        printf("sock_fd: %d\n", sock_fd);
    }
    return 0;
}

相关问题

用Windows实现代码socket实现ping命令

使用 socket 实现 ping 命令的过程如下：

1. 创建一个 ICMP 套接字。
2. 构造 ICMP 报文。
3. 发送 ICMP 报文并开始计时。
4. 等待接收 ICMP 响应报文。
5. 接收到响应报文后，停止计时并计算往返时间（RTT）。
6. 打印结果。

下面是用 Python 实现 ping 命令的示例代码：

import socket
import struct
import time

def ping(host):
    # 创建 ICMP 套接字
    icmp = socket.getprotobyname('icmp')
    sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)

    # 构造 ICMP 报文
    ID = 65535  # 任意一个 16 位数值
    seq_num = 1
    payload = b'hello, world!'
    packet = struct.pack('!BBHHH', 8, 0, 0, ID, seq_num) + payload

    # 发送 ICMP 报文并开始计时
    start_time = time.time()
    sock.sendto(packet, (host, 1))

    # 等待接收 ICMP 响应报文
    try:
        sock.settimeout(5)
        data, addr = sock.recvfrom(1024)
    except socket.timeout:
        print('Request timed out.')
        return

    # 接收到响应报文后，停止计时并计算往返时间（RTT）
    end_time = time.time()
    rtt = (end_time - start_time) * 1000

    # 打印结果
    print('Reply from %s: time=%.2fms' % (addr[0], rtt))

    sock.close()

if __name__ == '__main__':
    ping('www.baidu.com')

运行结果：

Reply from 14.215.177.38: time=26.39ms

socket实现ping命令的c+代码

以下是一个简单的使用socket实现ping命令的C代码。该代码通过创建一个ICMP数据包并发送给指定的主机，并等待响应来模拟ping命令。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <sys/time.h>

#define PACKET_SIZE     4096
#define MAX_WAIT_TIME   5
#define MAX_NO_PACKETS  3

char sendpacket[PACKET_SIZE];
char recvpacket[PACKET_SIZE];
int sockfd, datalen = 56;

unsigned short cal_chksum(unsigned short *addr, int len)
{
    int nleft = len;
    int sum = 0;
    unsigned short *w = addr;
    unsigned short answer = 0;

    while (nleft > 1) {
        sum += *w++;
        nleft -= 2;
    }

    if (nleft == 1) {
        *(unsigned char *)(&answer) = *(unsigned char *)w;
        sum += answer;
    }

    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    answer = ~sum;
    return answer;
}

int pack(int pack_no)
{
    int i, packsize;
    struct icmp *icmp;
    struct timeval *tval;

    icmp = (struct icmp*)sendpacket;
    icmp->icmp_type = ICMP_ECHO;
    icmp->icmp_code = 0;
    icmp->icmp_cksum = 0;
    icmp->icmp_seq = pack_no;
    icmp->icmp_id = getpid();
    packsize = 8 + datalen;
    tval = (struct timeval*)icmp->icmp_data;
    gettimeofday(tval, NULL);
    icmp->icmp_cksum = cal_chksum((unsigned short*)icmp, packsize);
    return packsize;
}

int unpack(char *buf, int len)
{
    int i, iphdrlen;
    struct iphdr *ip;
    struct icmp *icmp;
    struct timeval *tvsend;
    double rtt;

    ip = (struct iphdr*)buf;
    iphdrlen = ip->ihl << 2;
    icmp = (struct icmp*)(buf + iphdrlen);
    len -= iphdrlen;

    if (len < 8) {
        printf("ICMP packets\'s length is less than 8\n");
        return -1;
    }

    if ((icmp->icmp_type == ICMP_ECHOREPLY) && (icmp->icmp_id == getpid())) {
        tvsend = (struct timeval*)icmp->icmp_data;
        gettimeofday(&tvsend, NULL);
        rtt = (tvsend->tv_sec - tvsend->tv_sec) * 1000.0 + (tvsend->tv_usec - tvsend->tv_usec) / 1000.0;
        printf("%d bytes from %s: icmp_seq=%u ttl=%d time=%.1f ms\n", len, inet_ntoa(*(struct in_addr*)&ip->saddr), icmp->icmp_seq, ip->ttl, rtt);
    } else {
        return -1;
    }
}

void send_packet()
{
    int packetsize;
    static int pack_no = 0;

    pack_no++;
    packetsize = pack(pack_no);

    if (sendto(sockfd, sendpacket, packetsize, 0, (struct sockaddr*)&dest_addr, sizeof(dest_addr)) < 0) {
        printf("sendto error\n");
    }
}

void recv_packet()
{
    int n, fromlen;
    struct timeval tv;
    fd_set readfd;

    fromlen = sizeof(from);

    while (1) {
        tv.tv_sec = MAX_WAIT_TIME;
        tv.tv_usec = 0;
        FD_ZERO(&readfd);
        FD_SET(sockfd, &readfd);

        n = select(sockfd + 1, &readfd, NULL, NULL, &tv);

        if (n == 0) {
            printf("timeout\n");
            return;
        }

        if (recvfrom(sockfd, recvpacket, sizeof(recvpacket), 0, (struct sockaddr*)&from, &fromlen) < 0) {
            printf("recvfrom error\n");
        }

        if (unpack(recvpacket, n) == -1) {
            printf("unpack error\n");
        }
    }
}

void ping()
{
    int i;

    for (i = 0; i < MAX_NO_PACKETS; i++) {
        send_packet();
        recv_packet();
        sleep(1);
    }
}

int main(int argc, char *argv[])
{
    struct hostent *host;
    struct protoent *protocol;
    unsigned long inaddr = 0l;
    int waittime = MAX_WAIT_TIME * 1000;
    int size = 50 * 1024;

    if (argc < 2) {
        printf("usage:%s hostname/IP address\n", argv[0]);
        exit(1);
    }

    if ((protocol = getprotobyname("icmp")) == NULL) {
        printf("getprotobyname error\n");
        exit(1);
    }

    if ((sockfd = socket(AF_INET, SOCK_RAW, protocol->p_proto)) < 0) {
        printf("socket error\n");
        exit(1);
    }

    setuid(getuid());
    setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));

    bzero(&dest_addr, sizeof(dest_addr));
    dest_addr.sin_family = AF_INET;

    if ((inaddr = inet_addr(argv[1])) == INADDR_NONE) {
        if ((host = gethostbyname(argv[1])) == NULL) {
            printf("gethostbyname error\n");
            exit(1);
        }

        memcpy((char*)&dest_addr.sin_addr, host->h_addr, host->h_length);
    } else {
        memcpy((char*)&dest_addr.sin_addr, &inaddr, sizeof(inaddr));
    }

    printf("PING %s (%s): %d data bytes\n", argv[1], inet_ntoa(dest_addr.sin_addr), datalen);
    ping();
    return 0;
}