/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/* nm-openvpn-service-openvpn-helper - helper called after OpenVPN established
 * a connection, uses DBUS to send information back to nm-openvpn-service
 *
 * Tim Niemueller [www.niemueller.de]
 * Based on work by Dan Williams <dcbw@redhat.com>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * (C) Copyright 2005 Red Hat, Inc.
 * (C) Copyright 2005 Tim Niemueller
 *
 * $Id: nm-openvpn-service-openvpn-helper.c 4170 2008-10-11 14:44:45Z dcbw $
 * 
 */

#include <glib.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <regex.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <netdb.h>

#include <dbus/dbus.h>
#include <dbus/dbus-glib-lowlevel.h>
#include <dbus/dbus-glib.h>
#include <NetworkManager.h>

#include "nm-openvpn-service.h"
#include "nm-utils.h"

extern char **environ;

/* These are here because nm-dbus-glib-types.h isn't exported */
#define DBUS_TYPE_G_ARRAY_OF_UINT          (dbus_g_type_get_collection ("GArray", G_TYPE_UINT))
#define DBUS_TYPE_G_ARRAY_OF_ARRAY_OF_UINT (dbus_g_type_get_collection ("GPtrArray", DBUS_TYPE_G_ARRAY_OF_UINT))
#define DBUS_TYPE_G_PTR_ARRAY_OF_STRING    (dbus_g_type_get_collection ("GPtrArray", G_TYPE_STRING))

static void
helper_failed (DBusGConnection *connection, const char *reason)
{
	DBusGProxy *proxy;
	GError *err = NULL;

	g_warning ("nm-openvpn-service-openvpn-helper did not receive a valid %s from openvpn", reason);

	proxy = dbus_g_proxy_new_for_name (connection,
								NM_DBUS_SERVICE_OPENVPN,
								NM_VPN_DBUS_PLUGIN_PATH,
								NM_VPN_DBUS_PLUGIN_INTERFACE);

	dbus_g_proxy_call (proxy, "SetFailure", &err,
				    G_TYPE_STRING, reason,
				    G_TYPE_INVALID,
				    G_TYPE_INVALID);

	if (err) {
		g_warning ("Could not send failure information: %s", err->message);
		g_error_free (err);
	}

	g_object_unref (proxy);

	exit (1);
}

static void
send_ip4_config (DBusGConnection *connection, GHashTable *config)
{
	DBusGProxy *proxy;
	GError *err = NULL;

	proxy = dbus_g_proxy_new_for_name (connection,
								NM_DBUS_SERVICE_OPENVPN,
								NM_VPN_DBUS_PLUGIN_PATH,
								NM_VPN_DBUS_PLUGIN_INTERFACE);

	dbus_g_proxy_call (proxy, "SetIp4Config", &err,
				    dbus_g_type_get_map ("GHashTable", G_TYPE_STRING, G_TYPE_VALUE),
				    config,
				    G_TYPE_INVALID,
				    G_TYPE_INVALID);

	if (err) {
		g_warning ("Could not send failure information: %s", err->message);
		g_error_free (err);
	}

	g_object_unref (proxy);
}

static GValue *
str_to_gvalue (const char *str, gboolean try_convert)
{
	GValue *val;

	/* Empty */
	if (!str || strlen (str) < 1)
		return NULL;

	if (!g_utf8_validate (str, -1, NULL)) {
		if (try_convert && !(str = g_convert (str, -1, "ISO-8859-1", "UTF-8", NULL, NULL, NULL)))
			str = g_convert (str, -1, "C", "UTF-8", NULL, NULL, NULL);

		if (!str)
			/* Invalid */
			return NULL;
	}

	val = g_slice_new0 (GValue);
	g_value_init (val, G_TYPE_STRING);
	g_value_set_string (val, str);

	return val;
}

static GValue *
uint_to_gvalue (guint32 num)
{
	GValue *val;

	if (num == 0)
		return NULL;

	val = g_slice_new0 (GValue);
	g_value_init (val, G_TYPE_UINT);
	g_value_set_uint (val, num);

	return val;
}

static GValue *
addr_to_gvalue (const char *str)
{
	struct in_addr	temp_addr;
	GValue *val;

	/* Empty */
	if (!str || strlen (str) < 1)
		return NULL;

	if (inet_pton (AF_INET, str, &temp_addr) <= 0)
		return NULL;

	val = g_slice_new0 (GValue);
	g_value_init (val, G_TYPE_UINT);
	g_value_set_uint (val, temp_addr.s_addr);

	return val;
}

static GValue *
parse_addr_list (GValue *value_array, const char *str)
{
	char **split;
	int i;
	struct in_addr	temp_addr;
	GArray *array;

	/* Empty */
	if (!str || strlen (str) < 1)
		return value_array;

	if (value_array)
		array = (GArray *) g_value_get_boxed (value_array);
	else
		array = g_array_new (FALSE, FALSE, sizeof (guint));

	split = g_strsplit (str, " ", -1);
	for (i = 0; split[i]; i++) {
		if (inet_pton (AF_INET, split[i], &temp_addr) > 0)
			g_array_append_val (array, temp_addr.s_addr);
	}

	g_strfreev (split);

	if (!value_array && array->len > 0) {
		value_array = g_slice_new0 (GValue);
		g_value_init (value_array, DBUS_TYPE_G_UINT_ARRAY);
		g_value_set_boxed (value_array, array);
	}

	return value_array;
}

static inline gboolean
is_domain_valid (const char *str)
{
	return (str && (strlen(str) >= 1) && (strlen(str) <= 255));
}

static GValue *
get_routes (void)
{
	GValue *value = NULL;
	GPtrArray *routes;
	char *tmp;
	int i;

#define BUFLEN 256

	routes = g_ptr_array_new ();

	for (i = 1; i < 256; i++) {
		GArray *array;
		char buf[BUFLEN];
		struct in_addr network;
		struct in_addr netmask;
		struct in_addr gateway = { 0, };
		guint32 prefix, metric = 0;

		snprintf (buf, BUFLEN, "route_network_%d", i);
		tmp = getenv (buf);
		if (!tmp || strlen (tmp) < 1)
			break;

		if (inet_pton (AF_INET, tmp, &network) <= 0) {
			g_warning ("Ignoring invalid static route address '%s'", tmp ? tmp : "NULL");
			continue;
		}

		snprintf (buf, BUFLEN, "route_netmask_%d", i);
		tmp = getenv (buf);
		if (!tmp || inet_pton (AF_INET, tmp, &netmask) <= 0) {
			g_warning ("Ignoring invalid static route netmask '%s'", tmp ? tmp : "NULL");
			continue;
		}

		snprintf (buf, BUFLEN, "route_gateway_%d", i);
		tmp = getenv (buf);
		/* gateway can be missing */
		if (tmp && (inet_pton (AF_INET, tmp, &gateway) <= 0)) {
			g_warning ("Ignoring invalid static route gateway '%s'", tmp ? tmp : "NULL");
			continue;
		}

		snprintf (buf, BUFLEN, "route_metric_%d", i);
		tmp = getenv (buf);
		/* metric can be missing */
		if (tmp && strlen (tmp)) {
			long int tmp_metric;

			errno = 0;
			tmp_metric = strtol (tmp, NULL, 10);
			if (errno || tmp_metric < 0 || tmp_metric > G_MAXUINT32) {
				g_warning ("Ignoring invalid static route metric '%s'", tmp);
				continue;
			}
			metric = (guint32) tmp_metric;
		}

		array = g_array_sized_new (FALSE, TRUE, sizeof (guint32), 4);
		g_array_append_val (array, network.s_addr);
		prefix = nm_utils_ip4_netmask_to_prefix (netmask.s_addr);
		g_array_append_val (array, prefix);
		g_array_append_val (array, gateway.s_addr);
		g_array_append_val (array, metric);
		g_ptr_array_add (routes, array);
	}

	if (routes->len > 0) {
		value = g_new0 (GValue, 1);
		g_value_init (value, DBUS_TYPE_G_ARRAY_OF_ARRAY_OF_UINT);
		g_value_take_boxed (value, routes);
	} else
		g_ptr_array_free (routes, TRUE);

	return value;
}

static GValue *
trusted_remote_to_gvalue (void)
{
	char *tmp;
	GValue *val = NULL;
	struct in_addr addr;
	const char *p;
	gboolean is_name = FALSE;

	tmp = getenv ("trusted_ip");
	if (!tmp)
		tmp = getenv ("remote_1");
	if (!tmp) {
		g_warning ("%s: did not receive remote gateway address", __func__);
		return NULL;
	}

	/* Check if it seems to be a hostname hostname */
	p = tmp;
	while (*p) {
		if (*p != '.' && !isdigit (*p)) {
			is_name = TRUE;
			break;
		}
		p++;
	}

	/* Resolve a hostname if required */
	if (is_name) {
		struct addrinfo hints;
		struct addrinfo *result = NULL, *rp;
		int err;

		memset (&hints, 0, sizeof (hints));

		hints.ai_family = AF_INET;
		hints.ai_flags = AI_ADDRCONFIG;
		err = getaddrinfo (tmp, NULL, &hints, &result);
		if (err != 0) {
			g_warning ("%s: failed to look up VPN gateway address '%s' (%d)",
			           __func__, tmp, err);
			return NULL;
		}

		/* FIXME: so what if the name resolves to multiple IP addresses?  We
		 * don't know which one pptp decided to use so we could end up using a
		 * different one here, and the VPN just won't work.
		 */
		for (rp = result; rp; rp = rp->ai_next) {
			if (   (rp->ai_family == AF_INET)
			    && (rp->ai_addrlen == sizeof (struct sockaddr_in))) {
				struct sockaddr_in *inptr = (struct sockaddr_in *) rp->ai_addr;

				memcpy (&addr, &(inptr->sin_addr), sizeof (struct in_addr));
				break;
			}
		}

		freeaddrinfo (result);
	} else {
		errno = 0;
		if (inet_pton (AF_INET, tmp, &addr) <= 0) {
			g_warning ("%s: failed to convert VPN gateway address '%s' (%d)",
			           __func__, tmp, errno);
			return NULL;
		}
	}

	if (addr.s_addr != 0) {
		val = g_slice_new0 (GValue);
		g_value_init (val, G_TYPE_UINT);
		g_value_set_uint (val, addr.s_addr);
	} else {
		g_warning ("%s: failed to convert or look up VPN gateway address '%s'",
		           __func__, tmp);
	}

	return val;
}

int
main (int argc, char *argv[])
{
	DBusGConnection *connection;
	GHashTable *config;
	char *tmp;
	GValue *val;
	int i;
	GError *err = NULL;
	GValue *dns_list = NULL;
	GValue *nbns_list = NULL;
	GPtrArray *dns_domains = NULL;
	struct in_addr temp_addr;
	gboolean tapdev = FALSE;
	char **iter;

#if !GLIB_CHECK_VERSION (2, 35, 0)
	g_type_init ();
#endif

	connection = dbus_g_bus_get (DBUS_BUS_SYSTEM, &err);
	if (!connection) {
		g_warning ("Could not get the system bus: %s", err->message);
		exit (1);
	}

	if (argc >= 2 && !g_strcmp0 (argv[1], "--helper-debug")) {
		g_message ("openvpn script environment ---------------------------");
		iter = environ;
		while (iter && *iter)
			g_print ("%s\n", *iter++);
		g_message ("------------------------------------------------------");
	}

	config = g_hash_table_new (g_str_hash, g_str_equal);

	/* External world-visible VPN gateway */
	val = trusted_remote_to_gvalue ();
	if (val)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_EXT_GATEWAY, val);
	else
		helper_failed (connection, "VPN Gateway");

	/* Internal VPN subnet gateway */
	val = addr_to_gvalue (getenv ("route_vpn_gateway"));
	if (val)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_INT_GATEWAY, val);

	/* VPN device */
	tmp = getenv ("dev");
	val = str_to_gvalue (tmp, FALSE);
	if (val)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_TUNDEV, val);
	else
		helper_failed (connection, "Tunnel Device");

	if (strncmp (tmp, "tap", 3) == 0)
		tapdev = TRUE;

	/* IP address */
	val = addr_to_gvalue (getenv ("ifconfig_local"));
	if (val)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_ADDRESS, val);
	else
		helper_failed (connection, "IP4 Address");

	/* PTP address; for vpnc PTP address == internal IP4 address */
	val = addr_to_gvalue (getenv ("ifconfig_remote"));
	if (val) {
		/* Sigh.  Openvpn added 'topology' stuff in 2.1 that changes the meaning
		 * of the ifconfig bits without actually telling you what they are
		 * supposed to mean; basically relying on specific 'ifconfig' behavior.
		 */
		tmp = getenv ("ifconfig_remote");
		if (tmp && !strncmp (tmp, "255.", 4)) {
			guint32 addr;

			/* probably a netmask, not a PTP address; topology == subnet */
			addr = g_value_get_uint (val);
			g_value_set_uint (val, nm_utils_ip4_netmask_to_prefix (addr));
			g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_PREFIX, val);
		} else
			g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_PTP, val);
	}

	/* Netmask
	 *
	 * Either TAP or TUN modes can have an arbitrary netmask in newer versions
	 * of openvpn, while in older versions only TAP mode would.  So accept a
	 * netmask if passed, otherwise default to /32 for TUN devices since they
	 * are usually point-to-point.
	 */
	tmp = getenv ("ifconfig_netmask");
	if (tmp && inet_pton (AF_INET, tmp, &temp_addr) > 0) {
		val = g_slice_new0 (GValue);
		g_value_init (val, G_TYPE_UINT);
		g_value_set_uint (val, nm_utils_ip4_netmask_to_prefix (temp_addr.s_addr));
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_PREFIX, val);
	} else if (!tapdev) {
		if (!g_hash_table_lookup (config, NM_VPN_PLUGIN_IP4_CONFIG_PREFIX)) {
			val = g_slice_new0 (GValue);
			g_value_init (val, G_TYPE_UINT);
			g_value_set_uint (val, 32);
			g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_PREFIX, val);
		}
	} else
		g_warning ("No IP4 netmask/prefix (missing or invalid 'ifconfig_netmask')");

	val = get_routes ();
	if (val)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_ROUTES, val);

    	/* DNS and WINS servers */
	dns_domains = g_ptr_array_sized_new (3);
	for (i = 1; i < 256; i++) {
		char *env_name;

		env_name = g_strdup_printf ("foreign_option_%d", i);
		tmp = getenv (env_name);
		g_free (env_name);

		if (!tmp || strlen (tmp) < 1)
			break;

		if (!g_str_has_prefix (tmp, "dhcp-option "))
			continue;

		tmp += 12; /* strlen ("dhcp-option ") */

		if (g_str_has_prefix (tmp, "DNS "))
			dns_list = parse_addr_list (dns_list, tmp + 4);
		else if (g_str_has_prefix (tmp, "WINS "))
			nbns_list = parse_addr_list (nbns_list, tmp + 5);
		else if (g_str_has_prefix (tmp, "DOMAIN ") && is_domain_valid (tmp + 7))
			g_ptr_array_add (dns_domains, tmp + 7);
	}

	if (dns_list)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_DNS, dns_list);
	if (nbns_list)
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_NBNS, nbns_list);
	if (dns_domains->len) {
		val = g_slice_new0 (GValue);
		g_value_init (val, DBUS_TYPE_G_PTR_ARRAY_OF_STRING);
		g_value_take_boxed (val, dns_domains);
		g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_DOMAINS, val);
	} else
		g_ptr_array_free (dns_domains, TRUE);

	/* Tunnel MTU */
	tmp = getenv ("tun_mtu");
	if (tmp && strlen (tmp)) {
		long int mtu;

		errno = 0;
		mtu = strtol (tmp, NULL, 10);
		if (errno || mtu < 0 || mtu > 20000) {
			g_warning ("Ignoring invalid tunnel MTU '%s'", tmp);
		} else {
			val = uint_to_gvalue ((guint32) mtu);
			g_hash_table_insert (config, NM_VPN_PLUGIN_IP4_CONFIG_MTU, val);
		}
	}

	/* Send the config info to nm-openvpn-service */
	send_ip4_config (connection, config);

	return 0;
}
