#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

unsigned int ip2int(const char * s) {
	int ip[4];
	sscanf(s,"%d.%d.%d.%d",ip,ip+1,ip+2,ip+3);
	return ip[0]<<24|ip[1]<<16|ip[2]<<8|ip[3];
}

int sendall(int s, char *buf, int len, int flags)
{
    int total = 0;
    int n;

    while(total < len)
    {
        n = send(s, buf+total, len-total, flags);
        if(n == -1) { break; }
        total += n;
    }

    return (n==-1 ? -1 : total);
}

char message[] = "Hello there!\n";
char buf[sizeof(message)];

int main()
{
    int sock;
    struct sockaddr_in addr;

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

    addr.sin_family = AF_INET;
    addr.sin_port = htons(3425); // или любой другой порт...
    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);	// (ip2int("192.168.2.1"));
    if(connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
    {
        perror("connect");
        exit(2);
    }

    send(sock, message, sizeof(message), 0);
    recv(sock, buf, sizeof(message), 0);

    printf("%s\n",buf);
    close(sock);

    return 0;
}