帮我写一个利用http ping进行链路检测的C语言代码

以下是一个简单的利用http ping进行链路检测的C语言代码：

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

int main(int argc, char *argv[]) {
    if (argc 2) {
        printf("Usage: %s <hostname>\n", argv[0        exit(1);
    }

    char *hostname = argv[1];
    struct host *host = gethostbyname(hostname);

    if (!host) {
        printf("Error: not resolve hostname.\n");
        exit(1);
    }

    struct sockaddr_in addr;
 memcpy(&addr.sin_addr.s_addr, host->h_addr, 4);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(80);

    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        printf("Error: could not create socket.\n");
        exit(1);
    }

    if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
        printf("Error: could not connect to host.\n");
        exit(1);
    }

    char *request = "GET / HTTP/1.1\r\nHost: %s\r\nConnection: close\r\n\r\n";
    char buffer[1024] = {0};
    sprintf(buffer, request, hostname);

    clock_t start = clock();
    if (send(sock, buffer, strlen(buffer), 0) < 0) {
        printf("Error: could not send request.\n");
        exit(1);
    }

    if (recv(sock, buffer, sizeof(buffer), 0) < 0) {
        printf("Error: could not receive response.\n");
        exit(1);
    }
    clock_t end = clock();

    double time_spent = (double)(end - start) / CLOCKS_PER_SEC;
    printf("Response received in %lf seconds.\n", time_spent);

    close(sock);

    return 0;
}

该代码通过获取用户输入的主机名，使用 `gethostbyname()` 函数解析主机名，获取主机的 IP 地址。然后创建一个 TCP 套接字并连接到主机的 HTTP 端口（端口号为 80）。接着发送 HTTP GET 请求，并计算请求到响应的时间。最后关闭套接字。

需要注意的是，该代码只能测试主机是否能够响应 HTTP 请求，不能测试完整的网络链路的可用性。