server.c

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

#define SAMPLE_SERVER_CONN 10

int main(int argc, char **argv)
{
    int ret;
    int sock;
    int conn;
    int set_reuse = 1;
    struct sockaddr_in remote;
    socklen_t remote_len;

    if (argc != 3) {
        fprintf(stderr, "%s [ip] [port]\n", argv[0]);
        return -1;
    }

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("failed to socket\n");
        return -1;
    }

    ret = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &set_reuse, sizeof(set_reuse));
    if (ret < 0) {
        perror("failed to setsockopt\n");
        close(sock);
        return -1;
    }

    remote.sin_family = AF_INET;
    remote.sin_addr.s_addr = inet_addr(argv[1]);
    remote.sin_port = htons(atoi(argv[2]));

    ret = bind(sock, (struct sockaddr *)&remote, sizeof(remote));
    if (ret < 0) {
        perror("failed to bind\n");
        close(sock);
        return -1;
    }

    ret = listen(sock, SAMPLE_SERVER_CONN);
    if (ret < 0) {
        perror("failed to listen\n");
        close(sock);
        return -1;
    }

    remote_len = sizeof(struct sockaddr_in);

    conn = accept(sock, (struct sockaddr *)&remote, &remote_len);
    if (conn < 0) {
        perror("failed to accept\n");
        close(sock);
        return -1;
    }

    printf("new client %d\n", conn);

    close(conn);

    return 0;
}