iwd/src/netconfig.c

/*
 *
 *  Wireless daemon for Linux
 *
 *  Copyright (C) 2019  Intel Corporation. All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <errno.h>
#include <linux/rtnetlink.h>

#include <ell/ell.h>

#include "src/iwd.h"
#include "src/rtnlutil.h"
#include "src/netconfig.h"

struct netconfig {
	uint32_t ifindex;
	struct l_queue *ifaddr_list;
};

struct netconfig_ifaddr {
	uint8_t family;
	uint8_t prefix_len;
	char *ip;
	char *broadcast;
};

static struct l_netlink *rtnl;
static struct l_queue *netconfig_list;

static void do_debug(const char *str, void *user_data)
{
	const char *prefix = user_data;

	l_info("%s%s", prefix, str);
}

static void netconfig_ifaddr_destroy(void *data)
{
	struct netconfig_ifaddr *ifaddr = data;

	l_free(ifaddr->ip);
	l_free(ifaddr->broadcast);

	l_free(ifaddr);
}

static void netconfig_destroy(void *data)
{
	struct netconfig *netconfig = data;

	l_queue_destroy(netconfig->ifaddr_list, netconfig_ifaddr_destroy);

	l_free(netconfig);
}

static bool netconfig_match(const void *a, const void *b)
{
	const struct netconfig *netconfig = a;
	uint32_t ifindex = L_PTR_TO_UINT(b);

	if (netconfig->ifindex == ifindex)
		return true;

	return false;
}

static struct netconfig *netconfig_find(uint32_t ifindex)
{
	const struct l_queue_entry *entry;

	for (entry = l_queue_get_entries(netconfig_list); entry;
							entry = entry->next) {
		struct netconfig *netconfig = entry->data;

		if (netconfig->ifindex != ifindex)
			continue;

		return netconfig;
	}

	return NULL;
}

static struct netconfig_ifaddr *netconfig_ifaddr_find(
					const struct netconfig *netconfig,
					uint8_t family, uint8_t prefix_len,
					const char *ip)
{
	const struct l_queue_entry *entry;

	for (entry = l_queue_get_entries(netconfig->ifaddr_list); entry;
							entry = entry->next) {
		struct netconfig_ifaddr *ifaddr = entry->data;

		if (ifaddr->family != family)
			continue;

		if (ifaddr->prefix_len != prefix_len)
			continue;

		if (strcmp(ifaddr->ip, ip))
			continue;

		return ifaddr;
	}

	return NULL;
}

static void netconfig_ifaddr_added(struct netconfig *netconfig,
					const struct ifaddrmsg *ifa, int bytes)
{
	struct netconfig_ifaddr *ifaddr;
	char *label;

	ifaddr = l_new(struct netconfig_ifaddr, 1);
	ifaddr->family = ifa->ifa_family;
	ifaddr->prefix_len = ifa->ifa_prefixlen;

	rtnl_ifaddr_extract(ifa, bytes, &label, &ifaddr->ip,
							&ifaddr->broadcast);

	l_debug("%s: ifaddr %s/%u broadcast %s", label, ifaddr->ip,
					ifaddr->prefix_len, ifaddr->broadcast);
	l_free(label);

	l_queue_push_tail(netconfig->ifaddr_list, ifaddr);
}

static void netconfig_ifaddr_deleted(struct netconfig *netconfig,
					const struct ifaddrmsg *ifa, int bytes)
{
	struct netconfig_ifaddr *ifaddr;
	char *ip;

	rtnl_ifaddr_extract(ifa, bytes, NULL, &ip, NULL);

	ifaddr = netconfig_ifaddr_find(netconfig, ifa->ifa_family,
							ifa->ifa_prefixlen, ip);

	l_free(ip);

	if (!ifaddr)
		return;

	l_debug("ifaddr %s/%u", ifaddr->ip, ifaddr->prefix_len);

	l_queue_remove(netconfig->ifaddr_list, ifaddr);

	netconfig_ifaddr_destroy(ifaddr);
}

static void netconfig_ifaddr_notify(uint16_t type, const void *data,
						uint32_t len, void *user_data)
{
	const struct ifaddrmsg *ifa = data;
	struct netconfig *netconfig;
	unsigned int bytes;

	netconfig = netconfig_find(ifa->ifa_index);
	if (!netconfig)
		/* Ignore the interfaces which aren't managed by iwd. */
		return;

	bytes = len - NLMSG_ALIGN(sizeof(struct ifaddrmsg));

	switch (type) {
	case RTM_NEWADDR:
		netconfig_ifaddr_added(netconfig, ifa, bytes);
		break;
	case RTM_DELADDR:
		netconfig_ifaddr_deleted(netconfig, ifa, bytes);
		break;
	}
}

static void netconfig_ifaddr_cmd_cb(int error, uint16_t type,
						const void *data, uint32_t len,
						void *user_data)
{
	if (error) {
		l_error("netconfig: ifaddr command failure. "
				"Error %d: %s", error, strerror(-error));
		return;
	}

	if (type != RTM_NEWADDR)
		return;

	netconfig_ifaddr_notify(type, data, len, user_data);
}

bool netconfig_ifindex_add(uint32_t ifindex)
{
	struct netconfig *netconfig;

	if (!netconfig_list)
		return false;

	l_debug("Starting netconfig for interface: %d", ifindex);

	netconfig = netconfig_find(ifindex);
	if (netconfig)
		return true;

	netconfig = l_new(struct netconfig, 1);
	netconfig->ifindex = ifindex;
	netconfig->ifaddr_list = l_queue_new();

	l_queue_push_tail(netconfig_list, netconfig);

	return true;
}

bool netconfig_ifindex_remove(uint32_t ifindex)
{
	struct netconfig *netconfig;

	if (!netconfig_list)
		return false;

	l_debug();

	netconfig = l_queue_remove_if(netconfig_list, netconfig_match,
							L_UINT_TO_PTR(ifindex));
	if (!netconfig)
		return false;

	netconfig_destroy(netconfig);

	return true;
}

static int netconfig_init(void)
{
	bool enabled;
	uint32_t r;

	if (netconfig_list)
		return -EALREADY;

	if (!l_settings_get_bool(iwd_get_config(), "General",
					"enable_network_config", &enabled) ||
								!enabled) {
		l_warn("netconfig: Network configuration with the IP addresses "
								"is disabled.");
		return false;
	}

	rtnl = l_netlink_new(NETLINK_ROUTE);
	if (!rtnl) {
		l_error("netconfig: Failed to open route netlink socket");
		return -EPERM;
	}

	if (getenv("IWD_RTNL_DEBUG"))
		l_netlink_set_debug(rtnl, do_debug, "[NETCONFIG RTNL] ", NULL);

	r = l_netlink_register(rtnl, RTNLGRP_IPV4_IFADDR,
					netconfig_ifaddr_notify, NULL, NULL);
	if (!r) {
		l_error("netconfig: Failed to register for RTNL link address"
							" notifications.");
		l_netlink_destroy(rtnl);
		rtnl = NULL;

		return r;
	}

	r = rtnl_ifaddr_get(rtnl, netconfig_ifaddr_cmd_cb, NULL, NULL);
	if (!r) {
		l_error("netconfig: Failed to get addresses from RTNL link.");
		l_netlink_destroy(rtnl);
		rtnl = NULL;

		return r;
	}

	netconfig_list = l_queue_new();

	return 0;
}

static void netconfig_exit(void)
{
	if (!netconfig_list)
		return;

	l_netlink_destroy(rtnl);
	rtnl = NULL;

	l_queue_destroy(netconfig_list, netconfig_destroy);
}

IWD_MODULE(netconfig, netconfig_init, netconfig_exit)