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[NETFILTER]: nf_conntrack: automatic sysctl registation for conntrack protocols 

Add helper functions for sysctl registration with optional instantiating
of common path elements (like net/netfilter) and use it for support for
automatic registation of conntrack protocol sysctls.

Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy 2006-11-29 02:35:17 +01:00 committed by David S. Miller
parent f8eb24a89a
commit d62f9ed4a4
6 changed files with 259 additions and 0 deletions
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10
include/linux/netfilter.h
View File

@ -117,6 +117,16 @@ void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
int nf_register_sockopt(struct nf_sockopt_ops *reg);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
#ifdef CONFIG_SYSCTL
/* Sysctl registration */
struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
struct ctl_table *table);
void nf_unregister_sysctl_table(struct ctl_table_header *header,
struct ctl_table *table);
extern struct ctl_table nf_net_netfilter_sysctl_path[];
extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
#endif /* CONFIG_SYSCTL */
extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will

6
include/net/netfilter/nf_conntrack_l3proto.h
View File

@ -75,6 +75,12 @@ struct nf_conntrack_l3proto
int (*nfattr_to_tuple)(struct nfattr *tb[],
struct nf_conntrack_tuple *t);
#ifdef CONFIG_SYSCTL
struct ctl_table_header *ctl_table_header;
struct ctl_table *ctl_table_path;
struct ctl_table *ctl_table;
#endif /* CONFIG_SYSCTL */
/* Module (if any) which this is connected to. */
struct module *me;
};

6
include/net/netfilter/nf_conntrack_l4proto.h
View File

@ -76,6 +76,12 @@ struct nf_conntrack_l4proto
int (*nfattr_to_tuple)(struct nfattr *tb[],
struct nf_conntrack_tuple *t);
#ifdef CONFIG_SYSCTL
struct ctl_table_header **ctl_table_header;
struct ctl_table *ctl_table;
unsigned int *ctl_table_users;
#endif /* CONFIG_SYSCTL */
/* Module (if any) which this is connected to. */
struct module *me;
};

1
net/netfilter/Makefile
View File

@ -4,6 +4,7 @@ nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_exp
nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o
obj-$(CONFIG_NETFILTER) = netfilter.o
obj-$(CONFIG_SYSCTL) += nf_sysctl.o
obj-$(CONFIG_NETFILTER_NETLINK) += nfnetlink.o
obj-$(CONFIG_NETFILTER_NETLINK_QUEUE) += nfnetlink_queue.o

102
net/netfilter/nf_conntrack_proto.c
View File

@ -12,6 +12,7 @@
#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/stddef.h>
@ -30,6 +31,34 @@
struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
#ifdef CONFIG_SYSCTL
static DEFINE_MUTEX(nf_ct_proto_sysctl_mutex);
static int
nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_table *path,
struct ctl_table *table, unsigned int *users)
{
if (*header == NULL) {
*header = nf_register_sysctl_table(path, table);
if (*header == NULL)
return -ENOMEM;
}
if (users != NULL)
(*users)++;
return 0;
}
static void
nf_ct_unregister_sysctl(struct ctl_table_header **header,
struct ctl_table *table, unsigned int *users)
{
if (users != NULL && --*users > 0)
return;
nf_unregister_sysctl_table(*header, table);
*header = NULL;
}
#endif
struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
{
@ -124,6 +153,33 @@ static int kill_l4proto(struct nf_conn *i, void *data)
l4proto->l3proto);
}
static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
{
int err = 0;
#ifdef CONFIG_SYSCTL
mutex_lock(&nf_ct_proto_sysctl_mutex);
if (l3proto->ctl_table != NULL) {
err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
l3proto->ctl_table_path,
l3proto->ctl_table, NULL);
}
mutex_unlock(&nf_ct_proto_sysctl_mutex);
#endif
return err;
}
static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
{
#ifdef CONFIG_SYSCTL
mutex_lock(&nf_ct_proto_sysctl_mutex);
if (l3proto->ctl_table_header != NULL)
nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
l3proto->ctl_table, NULL);
mutex_unlock(&nf_ct_proto_sysctl_mutex);
#endif
}
int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
{
int ret = 0;
@ -139,6 +195,12 @@ int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
goto out_unlock;
}
nf_ct_l3protos[proto->l3proto] = proto;
write_unlock_bh(&nf_conntrack_lock);
ret = nf_ct_l3proto_register_sysctl(proto);
if (ret < 0)
nf_conntrack_l3proto_unregister(proto);
return ret;
out_unlock:
write_unlock_bh(&nf_conntrack_lock);
@ -165,6 +227,8 @@ int nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
nf_ct_l3protos[proto->l3proto] = &nf_conntrack_l3proto_generic;
write_unlock_bh(&nf_conntrack_lock);
nf_ct_l3proto_unregister_sysctl(proto);
/* Somebody could be still looking at the proto in bh. */
synchronize_net();
@ -175,6 +239,36 @@ out:
return ret;
}
static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
{
int err = 0;
#ifdef CONFIG_SYSCTL
mutex_lock(&nf_ct_proto_sysctl_mutex);
if (l4proto->ctl_table != NULL) {
err = nf_ct_register_sysctl(l4proto->ctl_table_header,
nf_net_netfilter_sysctl_path,
l4proto->ctl_table,
l4proto->ctl_table_users);
}
mutex_unlock(&nf_ct_proto_sysctl_mutex);
#endif
return err;
}
static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
{
#ifdef CONFIG_SYSCTL
mutex_lock(&nf_ct_proto_sysctl_mutex);
if (l4proto->ctl_table_header != NULL &&
*l4proto->ctl_table_header != NULL)
nf_ct_unregister_sysctl(l4proto->ctl_table_header,
l4proto->ctl_table,
l4proto->ctl_table_users);
mutex_unlock(&nf_ct_proto_sysctl_mutex);
#endif
}
/* FIXME: Allow NULL functions and sub in pointers to generic for
them. --RR */
int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
@ -230,6 +324,12 @@ retry:
}
nf_ct_protos[l4proto->l3proto][l4proto->l4proto] = l4proto;
write_unlock_bh(&nf_conntrack_lock);
ret = nf_ct_l4proto_register_sysctl(l4proto);
if (ret < 0)
nf_conntrack_l4proto_unregister(l4proto);
return ret;
out_unlock:
write_unlock_bh(&nf_conntrack_lock);
@ -257,6 +357,8 @@ int nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
= &nf_conntrack_l4proto_generic;
write_unlock_bh(&nf_conntrack_lock);
nf_ct_l4proto_unregister_sysctl(l4proto);
/* Somebody could be still looking at the proto in bh. */
synchronize_net();

134
net/netfilter/nf_sysctl.c Normal file
View File

@ -0,0 +1,134 @@
/* nf_sysctl.c netfilter sysctl registration/unregistation
*
* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
*/
#include <linux/module.h>
#include <linux/sysctl.h>
#include <linux/string.h>
#include <linux/slab.h>
static void
path_free(struct ctl_table *path, struct ctl_table *table)
{
struct ctl_table *t, *next;
for (t = path; t != NULL && t != table; t = next) {
next = t->child;
kfree(t);
}
}
static struct ctl_table *
path_dup(struct ctl_table *path, struct ctl_table *table)
{
struct ctl_table *t, *last = NULL, *tmp;
for (t = path; t != NULL; t = t->child) {
/* twice the size since path elements are terminated by an
* empty element */
tmp = kmemdup(t, 2 * sizeof(*t), GFP_KERNEL);
if (tmp == NULL) {
if (last != NULL)
path_free(path, table);
return NULL;
}
if (last != NULL)
last->child = tmp;
else
path = tmp;
last = tmp;
}
if (last != NULL)
last->child = table;
else
path = table;
return path;
}
struct ctl_table_header *
nf_register_sysctl_table(struct ctl_table *path, struct ctl_table *table)
{
struct ctl_table_header *header;
path = path_dup(path, table);
if (path == NULL)
return NULL;
header = register_sysctl_table(path, 0);
if (header == NULL)
path_free(path, table);
return header;
}
EXPORT_SYMBOL_GPL(nf_register_sysctl_table);
void
nf_unregister_sysctl_table(struct ctl_table_header *header,
struct ctl_table *table)
{
struct ctl_table *path = header->ctl_table;
unregister_sysctl_table(header);
path_free(path, table);
}
EXPORT_SYMBOL_GPL(nf_unregister_sysctl_table);
/* net/netfilter */
static struct ctl_table nf_net_netfilter_table[] = {
{
.ctl_name = NET_NETFILTER,
.procname = "netfilter",
.mode = 0555,
},
{
.ctl_name = 0
}
};
struct ctl_table nf_net_netfilter_sysctl_path[] = {
{
.ctl_name = CTL_NET,
.procname = "net",
.mode = 0555,
.child = nf_net_netfilter_table,
},
{
.ctl_name = 0
}
};
EXPORT_SYMBOL_GPL(nf_net_netfilter_sysctl_path);
/* net/ipv4/netfilter */
static struct ctl_table nf_net_ipv4_netfilter_table[] = {
{
.ctl_name = NET_IPV4_NETFILTER,
.procname = "netfilter",
.mode = 0555,
},
{
.ctl_name = 0
}
};
static struct ctl_table nf_net_ipv4_table[] = {
{
.ctl_name = NET_IPV4,
.procname = "ipv4",
.mode = 0555,
.child = nf_net_ipv4_netfilter_table,
},
{
.ctl_name = 0
}
};
struct ctl_table nf_net_ipv4_netfilter_sysctl_path[] = {
{
.ctl_name = CTL_NET,
.procname = "net",
.mode = 0555,
.child = nf_net_ipv4_table,
},
{
.ctl_name = 0
}
};
EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path);