#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <strings.h>

void error(char *msg)
{
	perror(msg);
	exit(0);
}

int server(int port)
{
	int sockfd, newsockfd, clilen;
	struct sockaddr_in serv_addr, cli_addr;
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) 
		error("ERROR opening socket");
	bzero((char *) &serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = INADDR_ANY;
	serv_addr.sin_port = htons(port);
	if (bind(sockfd, (struct sockaddr *) &serv_addr,
		sizeof(serv_addr)) < 0) 
		error("ERROR on binding");
	listen(sockfd,5);
	clilen = sizeof(cli_addr);
	newsockfd = accept(sockfd, 
			 (struct sockaddr *) &cli_addr, 
			 &clilen);
	if (newsockfd < 0)
		error("ERROR on accept");

	return newsockfd;
}

int client(struct hostent *server, int port)
{
	int sockfd, n;
	struct sockaddr_in serv_addr;
	char buffer[25];
	
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	
	if (sockfd < 0) 
		error("ERROR opening socket");
		
	if (server == NULL) {
		fprintf(stderr,"ERROR, no such host\n");
		exit(0);
	}
		
	bzero((char *) &serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	bcopy((char *)server->h_addr, 
		(char *)&serv_addr.sin_addr.s_addr,
		server->h_length);
	serv_addr.sin_port = htons(port);
		
	if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0) 
		error("ERROR connecting");
	
	return sockfd;
}

int main(int argc, char *argv[])
{
	int clientfd, serverfd;
	
	if (argc < 4) {
		fprintf(stderr,"usage %s hostname con_port listen_port\n", argv[0]);
		exit(0);
	}
	
	clientfd = client(gethostbyname(argv[1]), atoi(argv[2]));
	serverfd = server(atoi(argv[3]));
	
	pid_t pID1 = fork();
	if (pID1 == 0) {
		int n;
		char buffer[25];
		bzero(buffer,25);
		while ((n = recv(clientfd,buffer,25, 0)) > 0) {
			char* t = strstr(buffer, "bug26489");
			if (t) {
				write(serverfd, buffer, n);
				write(serverfd, t, n);
			} else
				write(serverfd, buffer, n);
			bzero(buffer,25);
		}
	} else if (pID1 < 0) {
		fprintf(stderr,"Failed to fork");
		exit(1);
	} else {
		pid_t pID2 = fork();
		if (pID2 == 0) {
			int n;
			char buffer[25];
			bzero(buffer,25);
			while ((n = recv(serverfd,buffer,25, 0)) > 0) {
				write(clientfd, buffer, n);
				bzero(buffer,25);
			}
		} else if (pID2 < 0) {
			fprintf(stderr,"Failed to fork");
			exit(1);
		}
	}
	
	return 0;
}