linux c设置mtu

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

int main(int argc, char *argv[])
{
    int sockfd;
    struct sockaddr_in serv_addr;
    socklen_t length;

    if (argc != 3) {
        fprintf(stderr, "Usage: %s<ip> <mtu>\n", argv[0]);
        exit(1);
    }

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        perror("socket");
        exit(1);
    }

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(0);

    if (inet_pton(AF_INET, argv[1], &serv_addr.sin_addr) <= 0) {
        perror("inet_pton");
        exit(1);
    }

    int mtu = atoi(argv[2]);
    if (setsockopt(sockfd, IPPROTO_IP, IP_MTU, &mtu, sizeof(mtu)) < 0) {
        perror("setsockopt");
        exit(1);
    }

    printf("MTU set to %d\n", mtu);

    close(sockfd);
    return 0;
}