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[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: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Thomas Graf 2007-03-22 11:48:11 -07:00 committed by David S. Miller
parent 30833ffead
commit e284986385
3 changed files with 184 additions and 29 deletions
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7
include/linux/rtnetlink.h
View File

@ -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,

18
include/net/rtnetlink.h Normal file
View File

@ -0,0 +1,18 @@
#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

188
net/core/rtnetlink.c
View File

@ -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 @@ errout:
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);