#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <pthread.h>

using namespace std;

const unsigned port = 51000;
const unsigned MAXBUFLEN = 512;

void *process_connection(void *arg) {
	int sockfd;
	ssize_t n;
	char buf[MAXBUFLEN];

	sockfd = *((int *)arg);
	free(arg);

	pthread_detach(pthread_self());
	while ((n = read(sockfd, buf, MAXBUFLEN)) > 0) {
		buf[n] = '\0';
		cout << buf << endl;
		write(sockfd, buf, strlen(buf));
	}
	if (n == 0) {
		cout << "client closed" << endl;
	} else {
		cout << "something wrong" << endl;
	}
	close(sockfd);
	return(NULL);
}

int main() {
	int serv_sockfd, cli_sockfd, *sock_ptr;
	struct sockaddr_in serv_addr, cli_addr;
	socklen_t sock_len;
	pthread_t tid;

	cout << "port = " << port << endl;
	serv_sockfd = socket(AF_INET, SOCK_STREAM, 0);

	bzero((void*)&serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	serv_addr.sin_port = htons(port);

	bind(serv_sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));

	listen(serv_sockfd, 5);

	for (; ;) {
		sock_len = sizeof(cli_addr);
		cli_sockfd = accept(serv_sockfd, (struct sockaddr *)&cli_addr, &sock_len);

		cout << "remote client IP == " << inet_ntoa(cli_addr.sin_addr);
		cout << ", port == " << ntohs(cli_addr.sin_port) << endl;

		sock_ptr = (int *)malloc(sizeof(int));
		*sock_ptr = cli_sockfd;

		pthread_create(&tid, NULL, &process_connection, (void
					*)sock_ptr);
	}
}