/*
 *  Quicktun tunnel driver - userspace cli tool
 *  Copyright (C) 2011 Matthias Schiffer <mschiffer@universe-factory.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 */

#include <stdio.h>
#include <string.h>

#include <netlink/netlink.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/ctrl.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "quicktun.h"


static void usage()
{
	fputs("Usage: qtctl show [ dev NAME ]\n"
	      "       qtctl add [ dev NAME ] [ mode { ethernet | ip } ]\n"
	      "                 [ local_address ADDRESS ] [ local_port PORT ]\n"
	      "                 [ remote_address ADDRESS ] [ remote_port PORT ]\n"
	      "                 [ remote_float { on | off } ]\n"
	      "       qtctl change dev NAME [ remote_address ADDRESS ] [ remote_port PORT ]\n"
	      "                    [ remote_float { on | off } ]\n"
	      "       qtctl del dev NAME\n", stderr);

	exit(2);
}

static int print_error(struct sockaddr_nl *nla, struct nlmsgerr *nlerr, void *arg)
{
	fprintf(stderr, "Error received: %s\n", strerror(-nlerr->error));
	exit(1);
}

static void add(int argc, char *argv[], struct nl_handle *sock, int family)
{
	struct nl_msg *msg;
	struct nl_cb *cb;

	int p = 0;
	uint16_t mode = QUICKTUN_MODE_ETHERNET;

	char *tmp_charp;
	struct in_addr tmp_addr;
	unsigned long tmp_ul;


	msg = nlmsg_alloc();
	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_ECHO, QUICKTUN_CMD_CREATE_DEVICE, 1);

	while ((++p) < argc) {
		if (!strcmp(argv[p], "dev")) {
			if ((++p) >= argc)
				usage();

			tmp_charp = strndup(argv[p], IFNAMSIZ - 1);
			nla_put_string(msg, QUICKTUN_A_IFNAME, tmp_charp);
			free(tmp_charp);
		}
		else if (!strcmp(argv[p], "mode")) {
			if ((++p) >= argc)
				usage();

			if (!strcmp(argv[p], "ethernet"))
				mode = QUICKTUN_MODE_ETHERNET;
			else if (!strcmp(argv[p], "ip"))
				mode = QUICKTUN_MODE_IP;
			else
				usage();
		}
		else if (!strcmp(argv[p], "local_address")) {
			if ((++p) >= argc)
				usage();

			if (!(inet_aton(argv[p], &tmp_addr)))
				usage();

			nla_put_u32(msg, QUICKTUN_A_LOCAL_ADDRESS, tmp_addr.s_addr);
		}
		else if (!strcmp(argv[p], "local_port")) {
			if ((++p) >= argc)
				usage();

			tmp_ul = strtoul(argv[p], &tmp_charp, 10);

			if (*tmp_charp)
				usage();

			nla_put_u16(msg, QUICKTUN_A_LOCAL_PORT, htons((short)tmp_ul));
		}
		else if (!strcmp(argv[p], "remote_address")) {
			if ((++p) >= argc)
				usage();

			if (!(inet_aton(argv[p], &tmp_addr)))
				usage();

			nla_put_u32(msg, QUICKTUN_A_REMOTE_ADDRESS, tmp_addr.s_addr);
		}
		else if (!strcmp(argv[p], "remote_port")) {
			if ((++p) >= argc)
				usage();

			tmp_ul = strtoul(argv[p], &tmp_charp, 10);

			if (*tmp_charp)
				usage();

			nla_put_u16(msg, QUICKTUN_A_REMOTE_PORT, htons((short)tmp_ul));
		}
		else if (!strcmp(argv[p], "remote_float")) {
			if ((++p) >= argc)
				usage();

			if (!strcmp(argv[p], "on"))
				nla_put_u8(msg, QUICKTUN_A_REMOTE_FLOAT, 1);
			else if (!strcmp(argv[p], "off"))
				nla_put_u8(msg, QUICKTUN_A_REMOTE_FLOAT, 0);
			else
				usage();
		}
		else
			usage();
	}

	nla_put_u16(msg, QUICKTUN_A_MODE, mode);

	nl_send_auto_complete(sock, msg);

	nlmsg_free(msg);

	cb = nl_cb_alloc(NL_CB_DEFAULT);
	nl_cb_err(cb, NL_CB_CUSTOM, print_error, NULL);

	nl_recvmsgs(sock, cb);
}

static void del(int argc, char *argv[], struct nl_handle *sock, int family)
{
	struct nl_msg *msg;
	struct nl_cb *cb;

	int p = 0;
	char *tmp_charp;

	int has_dev = 0;


	msg = nlmsg_alloc();
	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_ECHO, QUICKTUN_CMD_DELETE_DEVICE, 1);

	while ((++p) < argc) {
		if (!strcmp(argv[p], "dev")) {
			if ((++p) >= argc)
				usage();

			if (has_dev)
				usage();

			tmp_charp = strndup(argv[p], IFNAMSIZ - 1);
			nla_put_string(msg, QUICKTUN_A_IFNAME, tmp_charp);
			free(tmp_charp);

			has_dev = 1;
		}
		else
			usage();
	}

	if (!has_dev)
		usage();

	nl_send_auto_complete(sock, msg);

	nlmsg_free(msg);

	cb = nl_cb_alloc(NL_CB_DEFAULT);
	nl_cb_err(cb, NL_CB_CUSTOM, print_error, NULL);

	nl_recvmsgs(sock, cb);
}

static void change(int argc, char *argv[], struct nl_handle *sock, int family)
{
	struct nl_msg *msg;
	struct nl_cb *cb;

	int p = 0;

	char *tmp_charp;
	struct in_addr tmp_addr;
	unsigned long tmp_ul;

	int has_dev = 0;


	msg = nlmsg_alloc();
	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_ECHO, QUICKTUN_CMD_CHANGE_DEVICE, 1);

	while ((++p) < argc) {
		if (!strcmp(argv[p], "dev")) {
			if ((++p) >= argc)
				usage();

			if (has_dev)
				usage();

			tmp_charp = strndup(argv[p], IFNAMSIZ - 1);
			nla_put_string(msg, QUICKTUN_A_IFNAME, tmp_charp);
			free(tmp_charp);

			has_dev = 1;
		}
		else if (!strcmp(argv[p], "remote_address")) {
			if ((++p) >= argc)
				usage();

			if (!(inet_aton(argv[p], &tmp_addr)))
				usage();

			nla_put_u32(msg, QUICKTUN_A_REMOTE_ADDRESS, tmp_addr.s_addr);
		}
		else if (!strcmp(argv[p], "remote_port")) {
			if ((++p) >= argc)
				usage();

			tmp_ul = strtoul(argv[p], &tmp_charp, 10);

			if (*tmp_charp)
				usage();

			nla_put_u16(msg, QUICKTUN_A_REMOTE_PORT, htons((short)tmp_ul));
		}
		else if (!strcmp(argv[p], "remote_float")) {
			if ((++p) >= argc)
				usage();

			if (!strcmp(argv[p], "on"))
				nla_put_u8(msg, QUICKTUN_A_REMOTE_FLOAT, 1);
			else if (!strcmp(argv[p], "off"))
				nla_put_u8(msg, QUICKTUN_A_REMOTE_FLOAT, 0);
			else
				usage();
		}
		else
			usage();
	}

	if (!has_dev)
		usage();


	nl_send_auto_complete(sock, msg);

	nlmsg_free(msg);

	cb = nl_cb_alloc(NL_CB_DEFAULT);
	nl_cb_err(cb, NL_CB_CUSTOM, print_error, NULL);

	nl_recvmsgs(sock, cb);
}

static int show_callback(struct nl_msg *msg, void *arg)
{
	struct nlmsghdr *nlh = nlmsg_hdr(msg);
	struct genlmsghdr *ghdr;
	struct nlattr *pos, *pos2;
	struct nlattr *nested[__QUICKTUN_A_MAX];
	struct in_addr addr;
	int rem;

	if (!genlmsg_valid_hdr(nlh, 0)) {
		fputs("Received invalid data from kernel.", stderr);
		exit(1);
	}

	ghdr = nlmsg_data(nlh);

	if (ghdr->cmd != QUICKTUN_CMD_GET_DEVICE)
		return NL_OK;

	nla_for_each_attr(pos, genlmsg_attrdata(ghdr, 0), genlmsg_len(ghdr), rem) {
		nla_parse_nested(nested, QUICKTUN_A_MAX, pos, NULL);

		if(!nested[QUICKTUN_A_IFNAME] || !nested[QUICKTUN_A_MODE] || !nested[QUICKTUN_A_LOCAL_ADDRESS] || !nested[QUICKTUN_A_LOCAL_PORT]
		   || !nested[QUICKTUN_A_REMOTE_ADDRESS] || !nested[QUICKTUN_A_REMOTE_PORT] || !nested[QUICKTUN_A_REMOTE_FLOAT])
			continue;

		printf("%s: %s  ", nla_get_string(nested[QUICKTUN_A_IFNAME]), (nla_get_u16(nested[QUICKTUN_A_MODE]) == QUICKTUN_MODE_ETHERNET) ? "ethernet" : (nla_get_u16(nested[QUICKTUN_A_MODE]) == QUICKTUN_MODE_IP) ? "ip" : "unknown" );

		addr.s_addr = nla_get_u32(nested[QUICKTUN_A_LOCAL_ADDRESS]);
		printf("local %s:%u  ", inet_ntoa(addr), ntohs(nla_get_u16(nested[QUICKTUN_A_LOCAL_PORT])));

		addr.s_addr = nla_get_u32(nested[QUICKTUN_A_REMOTE_ADDRESS]);
		printf("remote %s:%u  ", inet_ntoa(addr), ntohs(nla_get_u16(nested[QUICKTUN_A_REMOTE_PORT])));

		printf("remote_float %s\n", nla_get_u8(nested[QUICKTUN_A_REMOTE_FLOAT]) ? "on" : "off");
	}

	return NL_STOP;
}

static void show(int argc, char *argv[], struct nl_handle *sock, int family)
{
	struct nl_msg *msg;
	struct nl_cb *cb;

	int p = 0;
	char *tmp_charp;

	int has_dev = 0;

	msg = nlmsg_alloc();
	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_ECHO, QUICKTUN_CMD_GET_DEVICE, 1);

	while ((++p) < argc) {
		if (!strcmp(argv[p], "dev")) {
			if ((++p) >= argc)
				usage();

			if (has_dev)
				usage();

			tmp_charp = strndup(argv[p], IFNAMSIZ - 1);
			nla_put_string(msg, QUICKTUN_A_IFNAME, tmp_charp);
			free(tmp_charp);

			has_dev = 1;
		}
	}

	nl_send_auto_complete(sock, msg);

	nlmsg_free(msg);

	cb = nl_cb_alloc(NL_CB_DEFAULT);
	nl_cb_set (cb, NL_CB_VALID, NL_CB_CUSTOM, show_callback, NULL);
	nl_cb_err(cb, NL_CB_CUSTOM, print_error, NULL);

	nl_recvmsgs(sock, cb);
}

int main(int argc, char *argv[])
{
	struct nl_handle *sock;
	int family;

	sock = nl_handle_alloc();
	genl_connect(sock);

	family = genl_ctrl_resolve(sock, "quicktun");
	if (family < 0) {
		fputs("Your kernel doesn't support Quicktun.\n", stderr);
		exit(1);
	}


	if (argc < 2)
		show(argc, argv, sock, family);
	else if (!strcmp(argv[1], "add"))
		add(argc-1, argv+1, sock, family);
	else if (!strcmp(argv[1], "del"))
		del(argc-1, argv+1, sock, family);
	else if (!strcmp(argv[1], "change"))
		change(argc-1, argv+1, sock, family);
	else if (!strcmp(argv[1], "show"))
		show(argc-1, argv+1, sock, family);
	else
		usage();

	return 0;
}