#include <arpa/inet.h>
#include <fcntl.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>


#define BUFSIZE 1024


void ext_out(int port, int out) {
	int server = socket(AF_INET6, SOCK_STREAM, 0);
	if (server == -1) {
		perror("socket");
		exit(1);
	}

	setsockopt(server, SOL_SOCKET, SO_REUSEADDR, &(int) {1}, sizeof (int));

	struct sockaddr_in6 server_addr = {0};
	server_addr.sin6_family = AF_INET6;
	server_addr.sin6_port = htons(port);
	server_addr.sin6_addr = in6addr_any;
	if (bind(server, (struct sockaddr *) &server_addr, sizeof server_addr) == -1) {
		perror("bind");
		exit(1);
	}
	char server_addr_pretty[INET6_ADDRSTRLEN] = "";
	inet_ntop(AF_INET6, &(server_addr.sin6_addr), server_addr_pretty, sizeof server_addr_pretty);
	printf("Écoute sur : %s\n", server_addr_pretty);

	if (listen(server, SOMAXCONN) == -1) {
		perror("listen");
		exit(1);
	}

	struct sockaddr_in6 client_addr;
	socklen_t client_addr_len;
	puts("Attente d’un client.");
	int client = accept(server, (struct sockaddr *) &client_addr, &client_addr_len);
	char client_addr_pretty[INET6_ADDRSTRLEN] = "";
	inet_ntop(AF_INET6, &(client_addr.sin6_addr), client_addr_pretty, sizeof client_addr_pretty);
	printf("Client connecté : %s\n", client_addr_pretty);

	char buf[BUFSIZE];
	ssize_t n;
	while (1) {
		n = read(client, buf, sizeof buf);
		if (n == -1) {
			perror("read");
			exit(1);
		}
		n = write(out, buf, n);
		if (n == -1) {
			perror("write");
			exit(1);
		}
	}

	close(client);
	close(server);
}


void ext_in(const char addr[], int port, int in) {
	int s = socket(AF_INET6, SOCK_STREAM, 0);
	if (s == -1) {
		perror("socket");
		exit(1);
	}

	struct sockaddr_in6 sa = {0};
	sa.sin6_family = AF_INET6;
	sa.sin6_port = htons(port);
	inet_pton(AF_INET6, addr, &sa.sin6_addr);

	puts("Connexion.");
	while (connect(s, (struct sockaddr *) &sa, sizeof sa) == -1) {
		perror("connect");
		sleep(1);
	}
	char addr_pretty[INET6_ADDRSTRLEN] = "";
	inet_ntop(AF_INET6, &(sa.sin6_addr), addr_pretty, sizeof addr_pretty);
	printf("Connecté à : %s\n", addr_pretty);

	char buf[BUFSIZE];
	ssize_t n;
	while (1) {
		n = read(in, buf, sizeof buf);
		if (n == -1) {
			perror("read");
			exit(1);
		}
		n = write(s, buf, n);
		if (n == -1) {
			perror("write");
			exit(1);
		}
	}

	close(s);
}


void ext_bidir(const char addr[], int port, int in, int out) {
	pid_t pid = fork();
	if (pid == 0) {
		ext_in(addr, port, in);
	}
	else {
		ext_out(port, out);
		waitpid(pid, NULL, 0);
	}
}