some-usable-scripts/c/libipc/client-tcp.c

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2020-01-28 12:41:11 +01:00
/**
* @section LICENSE
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details at
* http://www.gnu.org/copyleft/gpl.html
*
* @section DESCRIPTION
*
* Simple program that creates an IPv4 TCP socket and tries to connect
* to a remote host before sending a string to this host. The string,
* IPv4 addr and port number of the remote host are passed as command
* line parameters as follow:
* ./pg_name IPv4_addr port_number string
*/
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
int setup_connection (char *str_serveraddr, char *str_port)
{
int sockfd;
struct sockaddr_in server;
socklen_t addrlen;
// socket factory
if ((sockfd = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
perror ("socket");
exit (EXIT_FAILURE);
}
// init remote addr structure and other params
server.sin_family = AF_INET;
server.sin_port = htons (atoi (str_port));
addrlen = sizeof (struct sockaddr_in);
// get addr from command line and convert it
if (inet_pton (AF_INET, str_serveraddr, &server.sin_addr) != 1) {
perror ("inet_pton");
close (sockfd);
exit (EXIT_FAILURE);
}
printf ("Trying to connect to the remote host\n");
if (connect (sockfd, (struct sockaddr *)&server, addrlen) == -1) {
perror ("connect");
exit (EXIT_FAILURE);
}
return sockfd;
}
int send_msg(int sockfd, char *message)
{
int ret;
// send string
if ((ret = send (sockfd, message, strlen (message), 0)) == -1) {
perror ("send");
close (sockfd);
exit (EXIT_FAILURE);
}
return ret;
}
int recv_msg(int sockfd)
{
char buf[1024] = { 0 };
int ret;
// send string
if ((ret = recv (sockfd, buf, sizeof(buf), 0)) == -1) {
perror ("recv");
close (sockfd);
exit (EXIT_FAILURE);
}
printf ("message received: %s\n", buf);
return ret;
}
int main (int argc, char **argv)
{
int sockfd;
// check the number of args on command line
if (argc != 4) {
printf ("USAGE: %s @server port_num string\n", argv[0]);
exit (-1);
}
sockfd = setup_connection(argv[1], argv[2]);
printf ("Connection OK\n");
send_msg (sockfd, argv[3]);
send_msg (sockfd, argv[3]);
send_msg (sockfd, argv[3]);
send_msg (sockfd, argv[3]);
send_msg (sockfd, argv[3]);
recv_msg (sockfd);
printf ("Disconnection\n");
// close the socket
close (sockfd);
return 0;
}