#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>
#include <string.h>
 
#define MAXPENDING 5
#define BUFFER_SIZE 1024
#define EXIT_CALL "exit"
 
int main()
{
	int local_socket = 0, remote_socket = 0, message_length = 0, remote_length = 0;
	unsigned short local_port = 0, remote_port = 0;
	struct sockaddr_in local_address, remote_address;
	WSADATA wsa_data;
	char message[BUFFER_SIZE], remote_ip[32];
 
	printf("Enter local port to use: ");
	scanf("%d", &local_port);
	fflush(stdin);
 
	if(WSAStartup(MAKEWORD(2, 0), &wsa_data) != 0){
		fprintf(stderr, "WSAStartup() failed.\n");
		return (1);
	}
 
	if((local_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
		fprintf(stderr, "socket() failed.\n");
		return(1);
	}
 
	memset(&local_address, 0, sizeof(local_address));
	local_address.sin_family = AF_INET;
	local_address.sin_addr.s_addr = htonl(INADDR_ANY);
	local_address.sin_port = htons(local_port);
 
	if(bind(local_socket, (struct sockaddr *) &local_address, sizeof(local_address)) < 0){
		fprintf(stderr, "bind() failed.\n");
		return(1);
	}
 
	printf("Enter client IP: ");
	scanf("%s", remote_ip);
	fflush(stdin);
 
	printf("Enter client Port: ");
	scanf("%d", &remote_port);
	fflush(stdin);
 
	if((remote_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
		fprintf(stderr, "socket() failed.\n");
		return(1);
	}
 
	memset(&remote_address, 0, sizeof(remote_address));
	remote_address.sin_family = AF_INET;
	remote_address.sin_addr.s_addr = inet_addr(remote_ip);
	remote_address.sin_port = htons(remote_port);
 
	if(connect(remote_socket, (struct sockaddr *) &remote_address, sizeof(remote_address)) < 0){
		fprintf(stderr, "connect() failed.\n");
		return(1);
	}
 
	if(listen(local_socket, MAXPENDING) < 0){
		fprintf(stderr, "listen() failed\n");
		return(1);
	}
 
	do{
		memset(&message, 0, BUFFER_SIZE);
		if((message_length = recv(remote_socket, message, BUFFER_SIZE, 0)) < 0)
		{
			fprintf(stderr, "recv() failed.\n");
			return(1);
		}
 
		printf("From client %s: %s\n", inet_ntoa(remote_address.sin_addr), message);
	}while(strcmp(message, EXIT_CALL));
 
	WSACleanup();
	closesocket(local_socket);
	closesocket(remote_socket);
	return(0);
}

#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>
#include <string.h>
 
#define MAXPENDING 5
#define BUFFER_SIZE 1024
#define EXIT_CALL "exit"
 
int main()
{
	int local_socket = 0, remote_socket = 0, message_length = 0, remote_length = 0;
	unsigned short local_port = 0, remote_port = 0;
	struct sockaddr_in local_address, remote_address;
	WSADATA wsa_data;
	char message[BUFFER_SIZE];
 
	printf("Enter local port to use: ");
	scanf("%d", &local_port);
	fflush(stdin);
 
	if(WSAStartup(MAKEWORD(2, 0), &wsa_data) != 0){
		fprintf(stderr, "WSAStartup() failed.\n");
		return (1);
	}
 
	if((local_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
		fprintf(stderr, "socket() failed.\n");
		return(1);
	}
 
	memset(&local_address, 0, sizeof(local_address));
	local_address.sin_family = AF_INET;
	local_address.sin_addr.s_addr = htonl(INADDR_ANY);
	local_address.sin_port = htons(local_port);
 
	if(bind(local_socket, (struct sockaddr *) &local_address, sizeof(local_address)) < 0){
		fprintf(stderr, "bind() failed.\n");
		return(1);
	}
 
	if(listen(local_socket, MAXPENDING) < 0){
		fprintf(stderr, "listen() failed\n");
		return(1);
	}
 
	remote_length = sizeof(remote_address);
 
	for(;;){
		if((remote_socket = accept(local_socket, (struct sockaddr *) &remote_address, &remote_length) ) < 0){
			fprintf(stderr, "accept() failed.\n");
			return(1);
		}
		else{
			break;
		}
	}
 
	do{
		memset(&message, 0, BUFFER_SIZE);
		printf("Enter message to send: ");
		gets(message);
		fflush(stdin);
 
		message_length = (strlen(message));
 
		if (send(remote_socket, message, message_length, 0) != message_length){
			fprintf(stderr, "send() failed.\n");
			return(1);
		}
	}while(strcmp(message, EXIT_CALL));
 
	WSACleanup();
	closesocket(local_socket);
	closesocket(remote_socket);
	return(0);
}