path: root/net/core/rtnetlink.c

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Routing netlink socket interface: protocol independent part.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *		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.
 *
 *	Fixes:
 *	Vitaly E. Lavrov		RTA_OK arithmetics was wrong.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/if_addr.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/string.h>

#include <linux/inet.h>
#include <linux/netdevice.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/arp.h>
#include <net/route.h>
#include <net/udp.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/fib_rules.h>
#include <net/rtnetlink.h>
#ifdef CONFIG_NET_WIRELESS_RTNETLINK
#include <linux/wireless.h>
#include <net/iw_handler.h>
#endif	/* CONFIG_NET_WIRELESS_RTNETLINK */

struct rtnl_link
{
	rtnl_doit_func		doit;
	rtnl_dumpit_func	dumpit;
};

static DEFINE_MUTEX(rtnl_mutex);
static struct sock *rtnl;

void rtnl_lock(void)
{
	mutex_lock(&rtnl_mutex);
}

void __rtnl_unlock(void)
{
	mutex_unlock(&rtnl_mutex);
}

void rtnl_unlock(void)
{
	mutex_unlock(&rtnl_mutex);
	if (rtnl && rtnl->sk_receive_queue.qlen)
		rtnl->sk_data_ready(rtnl, 0);
	netdev_run_todo();
}

int rtnl_trylock(void)
{
	return mutex_trylock(&rtnl_mutex);
}

int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len)
{
	memset(tb, 0, sizeof(struct rtattr*)*maxattr);

	while (RTA_OK(rta, len)) {
		unsigned flavor = rta->rta_type;
		if (flavor && flavor <= maxattr)
			tb[flavor-1] = rta;
		rta = RTA_NEXT(rta, len);
	}
	return 0;
}

struct rtnl_link *rtnl_msg_handlers[NPROTO];

static inline int rtm_msgindex(int msgtype)
{
	int msgindex = msgtype - RTM_BASE;

	/*
	 * msgindex < 0 implies someone tried to register a netlink
	 * control code. msgindex >= RTM_NR_MSGTYPES may indicate that
	 * the message type has not been added to linux/rtnetlink.h
	 */
	BUG_ON(msgindex < 0 || msgindex >= RTM_NR_MSGTYPES);

	return msgindex;
}

static rtnl_doit_func rtnl_get_doit(int protocol, int msgindex)
{
	struct rtnl_link *tab;

	tab = rtnl_msg_handlers[protocol];
	if (tab == NULL || tab[msgindex].doit == NULL)
		tab = rtnl_msg_handlers[PF_UNSPEC];

	return tab ? tab[msgindex].doit : NULL;
}

static rtnl_dumpit_func rtnl_get_dumpit(int protocol, int msgindex)
{
	struct rtnl_link *tab;

	tab = rtnl_msg_handlers[protocol];
	if (tab == NULL || tab[msgindex].dumpit == NULL)
		tab = rtnl_msg_handlers[PF_UNSPEC];

	return tab ? tab[msgindex].dumpit : NULL;
}

/**
 * __rtnl_register - Register a rtnetlink message type
 * @protocol: Protocol family or PF_UNSPEC
 * @msgtype: rtnetlink message type
 * @doit: Function pointer called for each request message
 * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message
 *
 * Registers the specified function pointers (at least one of them has
 * to be non-NULL) to be called whenever a request message for the
 * specified protocol family and message type is received.
 *
 * The special protocol family PF_UNSPEC may be used to define fallback
 * function pointers for the case when no entry for the specific protocol
 * family exists.
 *
 * Returns 0 on success or a negative error code.
 */
int __rtnl_register(int protocol, int msgtype,
		    rtnl_doit_func doit, rtnl_dumpit_func dumpit)
{
	struct rtnl_link *tab;
	int msgindex;

	BUG_ON(protocol < 0 || protocol >= NPROTO);
	msgindex = rtm_msgindex(msgtype);

	tab = rtnl_msg_handlers[protocol];
	if (tab == NULL) {
		tab = kcalloc(RTM_NR_MSGTYPES, sizeof(*tab), GFP_KERNEL);
		if (tab == NULL)
			return -ENOBUFS;

		rtnl_msg_handlers[protocol] = tab;
	}

	if (doit)
		tab[msgindex].doit = doit;

	if (dumpit)
		tab[msgindex].dumpit = dumpit;

	return 0;
}

EXPORT_SYMBOL_GPL(__rtnl_register);

/**
 * rtnl_register - Register a rtnetlink message type
 *
 * Identical to __rtnl_register() but panics on failure. This is useful
 * as failure of this function is very unlikely, it can o