Commit e2849863 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

[RTNL]: Message handler registration interface 



This patch adds a new interface to register rtnetlink message
handlers replacing the exported rtnl_links[] array which
required many message handlers to be exported unnecessarly.

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 30833ffe

include/linux/rtnetlink.h

+0 −7
Original line number Diff line number Diff line
@@ -574,13 +574,6 @@ extern int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, in 
#define rtattr_parse_nested(tb, max, rta) \

	rtattr_parse((tb), (max), RTA_DATA((rta)), RTA_PAYLOAD((rta)))



struct rtnetlink_link

{

	int (*doit)(struct sk_buff *, struct nlmsghdr*, void *attr);

	int (*dumpit)(struct sk_buff *, struct netlink_callback *cb);

};



extern struct rtnetlink_link * rtnetlink_links[NPROTO];

extern int rtnetlink_send(struct sk_buff *skb, u32 pid, u32 group, int echo);

extern int rtnl_unicast(struct sk_buff *skb, u32 pid);

extern int rtnl_notify(struct sk_buff *skb, u32 pid, u32 group,

include/net/rtnetlink.h

0 → 100644
+18 −0
Original line number Diff line number Diff line 
#ifndef __NET_RTNETLINK_H

#define __NET_RTNETLINK_H



#include <linux/rtnetlink.h>

#include <net/netlink.h>



typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, void *);

typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);



extern int	__rtnl_register(int protocol, int msgtype,

				rtnl_doit_func, rtnl_dumpit_func);

extern void	rtnl_register(int protocol, int msgtype,

			      rtnl_doit_func, rtnl_dumpit_func);

extern int	rtnl_unregister(int protocol, int msgtype);

extern void	rtnl_unregister_all(int protocol);

extern int	rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb);



#endif

net/core/rtnetlink.c

+166 −22
Original line number Diff line number Diff line
@@ -50,12 +50,18 @@ 
#include <net/sock.h>

#include <net/pkt_sched.h>

#include <net/fib_rules.h>

#include <net/netlink.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;
@@ -95,7 +101,151 @@ int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len) 
	return 0;

}



struct rtnetlink_link * rtnetlink_links[NPROTO];

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->doit == NULL)

		tab = rtnl_msg_handlers[PF_UNSPEC];



	return tab ? tab->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->dumpit == NULL)

		tab = rtnl_msg_handlers[PF_UNSPEC];



	return tab ? tab->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 only happen due

 * to lack of memory when allocating the chain to store all message

 * handlers for a protocol. Meant for use in init functions where lack

 * of memory implies no sense in continueing.

 */

void rtnl_register(int protocol, int msgtype,

		   rtnl_doit_func doit, rtnl_dumpit_func dumpit)

{

	if (__rtnl_register(protocol, msgtype, doit, dumpit) < 0)

		panic("Unable to register rtnetlink message handler, "

		      "protocol = %d, message type = %d\n",

		      protocol, msgtype);

}



EXPORT_SYMBOL_GPL(rtnl_register);



/**

 * rtnl_unregister - Unregister a rtnetlink message type

 * @protocol: Protocol family or PF_UNSPEC

 * @msgtype: rtnetlink message type

 *

 * Returns 0 on success or a negative error code.

 */

int rtnl_unregister(int protocol, int msgtype)

{

	int msgindex;



	BUG_ON(protocol < 0 || protocol >= NPROTO);

	msgindex = rtm_msgindex(msgtype);



	if (rtnl_msg_handlers[protocol] == NULL)

		return -ENOENT;



	rtnl_msg_handlers[protocol][msgindex].doit = NULL;

	rtnl_msg_handlers[protocol][msgindex].dumpit = NULL;



	return 0;

}



EXPORT_SYMBOL_GPL(rtnl_unregister);



/**

 * rtnl_unregister_all - Unregister all rtnetlink message type of a protocol

 * @protocol : Protocol family or PF_UNSPEC

 *

 * Identical to calling rtnl_unregster() for all registered message types

 * of a certain protocol family.

 */

void rtnl_unregister_all(int protocol)

{

	BUG_ON(protocol < 0 || protocol >= NPROTO);



	kfree(rtnl_msg_handlers[protocol]);

	rtnl_msg_handlers[protocol] = NULL;

}



EXPORT_SYMBOL_GPL(rtnl_unregister_all);



static const int rtm_min[RTM_NR_FAMILIES] =

{
@@ -648,7 +798,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 
	return err;

}



static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)

int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)

{

	int idx;

	int s_idx = cb->family;
@@ -659,12 +809,12 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) 
		int type = cb->nlh->nlmsg_type-RTM_BASE;

		if (idx < s_idx || idx == PF_PACKET)

			continue;

		if (rtnetlink_links[idx] == NULL ||

		    rtnetlink_links[idx][type].dumpit == NULL)

		if (rtnl_msg_handlers[idx] == NULL ||

		    rtnl_msg_handlers[idx][type].dumpit == NULL)

			continue;

		if (idx > s_idx)

			memset(&cb->args[0], 0, sizeof(cb->args));

		if (rtnetlink_links[idx][type].dumpit(skb, cb))

		if (rtnl_msg_handlers[idx][type].dumpit(skb, cb))

			break;

	}

	cb->family = idx;
@@ -672,6 +822,8 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) 
	return skb->len;

}



EXPORT_SYMBOL_GPL(rtnl_dump_all);



void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)

{

	struct sk_buff *skb;
@@ -703,8 +855,7 @@ static int rtattr_max; 
static __inline__ int

rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)

{

	struct rtnetlink_link *link;

	struct rtnetlink_link *link_tab;

	rtnl_doit_func doit;

	int sz_idx, kind;

	int min_len;

	int family;
@@ -737,11 +888,6 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp) 
		return -1;

	}



	link_tab = rtnetlink_links[family];

	if (link_tab == NULL)

		link_tab = rtnetlink_links[PF_UNSPEC];

	link = &link_tab[type];



	sz_idx = type>>2;

	kind = type&3;
@@ -751,14 +897,14 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp) 
	}



	if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {

		if (link->dumpit == NULL)

			link = &(rtnetlink_links[PF_UNSPEC][type]);

		rtnl_dumpit_func dumpit;



		if (link->dumpit == NULL)

		dumpit = rtnl_get_dumpit(family, type);

		if (dumpit == NULL)

			goto err_inval;



		if ((*errp = netlink_dump_start(rtnl, skb, nlh,

						link->dumpit, NULL)) != 0) {

						dumpit, NULL)) != 0) {

			return -1;

		}
@@ -787,11 +933,10 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp) 
		}

	}



	if (link->doit == NULL)

		link = &(rtnetlink_links[PF_UNSPEC][type]);

	if (link->doit == NULL)

	doit = rtnl_get_doit(family, type);

	if (doit == NULL)

		goto err_inval;

	err = link->doit(skb, nlh, (void *)&rta_buf[0]);

	err = doit(skb, nlh, (void *)&rta_buf[0]);



	*errp = err;

	return err;
@@ -886,7 +1031,6 @@ void __init rtnetlink_init(void) 
EXPORT_SYMBOL(__rta_fill);

EXPORT_SYMBOL(rtattr_strlcpy);

EXPORT_SYMBOL(rtattr_parse);

EXPORT_SYMBOL(rtnetlink_links);

EXPORT_SYMBOL(rtnetlink_put_metrics);

EXPORT_SYMBOL(rtnl_lock);

EXPORT_SYMBOL(rtnl_trylock);