#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/un.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

/*
    Remote server: socat - tcp4-listen:667
*/

int main()
{
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);

    struct sockaddr_in servaddr;
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr=inet_addr("192.168.12.254");
    servaddr.sin_port=htons(667);

    int result = connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
    if(result != 0)
    {
        perror("failed to connect");
        exit(1);
    }

    char sendbuf[4096];
    memset(sendbuf, 0, sizeof(sendbuf));
    strcpy(sendbuf, "NOOP\n");

    int max_seg = 0, max_seg_len = sizeof(max_seg), get_res = 0;

    for (int i = 0; i < 10; ++i)
    {
        errno = 0;
        int send_res = send(sockfd, sendbuf, sizeof(sendbuf), 0);
        printf("[%d SEND result: %d, strerror: %s]\n", time(NULL), send_res, strerror(errno));

        get_res = getsockopt(sockfd, SOL_TCP, TCP_MAXSEG, &max_seg, &max_seg_len);
        printf("tcp max seg: res: %d, max_seg: %d\n", get_res, max_seg);
    }

    printf("All sent.\n");

    close(sockfd);
    exit(0);
}