It's C, not C++... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
225 lines
5.8 KiB
C
225 lines
5.8 KiB
C
/* Helper handling for netfilter. */
|
|
|
|
/* (C) 1999-2001 Paul `Rusty' Russell
|
|
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
|
|
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/random.h>
|
|
#include <linux/err.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/netdevice.h>
|
|
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_l3proto.h>
|
|
#include <net/netfilter/nf_conntrack_l4proto.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_core.h>
|
|
#include <net/netfilter/nf_conntrack_extend.h>
|
|
|
|
static struct hlist_head *nf_ct_helper_hash __read_mostly;
|
|
static unsigned int nf_ct_helper_hsize __read_mostly;
|
|
static unsigned int nf_ct_helper_count __read_mostly;
|
|
static int nf_ct_helper_vmalloc;
|
|
|
|
|
|
/* Stupid hash, but collision free for the default registrations of the
|
|
* helpers currently in the kernel. */
|
|
static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^
|
|
tuple->src.u.all) % nf_ct_helper_hsize;
|
|
}
|
|
|
|
struct nf_conntrack_helper *
|
|
__nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
struct nf_conntrack_helper *helper;
|
|
struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) };
|
|
struct hlist_node *n;
|
|
unsigned int h;
|
|
|
|
if (!nf_ct_helper_count)
|
|
return NULL;
|
|
|
|
h = helper_hash(tuple);
|
|
hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) {
|
|
if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
|
|
return helper;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
struct nf_conntrack_helper *
|
|
nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple)
|
|
{
|
|
struct nf_conntrack_helper *helper;
|
|
|
|
/* need nf_conntrack_lock to assure that helper exists until
|
|
* try_module_get() is called */
|
|
read_lock_bh(&nf_conntrack_lock);
|
|
|
|
helper = __nf_ct_helper_find(tuple);
|
|
if (helper) {
|
|
/* need to increase module usage count to assure helper will
|
|
* not go away while the caller is e.g. busy putting a
|
|
* conntrack in the hash that uses the helper */
|
|
if (!try_module_get(helper->me))
|
|
helper = NULL;
|
|
}
|
|
|
|
read_unlock_bh(&nf_conntrack_lock);
|
|
|
|
return helper;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_find_get);
|
|
|
|
void nf_ct_helper_put(struct nf_conntrack_helper *helper)
|
|
{
|
|
module_put(helper->me);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_put);
|
|
|
|
struct nf_conntrack_helper *
|
|
__nf_conntrack_helper_find_byname(const char *name)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
struct hlist_node *n;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < nf_ct_helper_hsize; i++) {
|
|
hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) {
|
|
if (!strcmp(h->name, name))
|
|
return h;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname);
|
|
|
|
struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
|
|
{
|
|
struct nf_conn_help *help;
|
|
|
|
help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp);
|
|
if (help)
|
|
INIT_HLIST_HEAD(&help->expectations);
|
|
else
|
|
pr_debug("failed to add helper extension area");
|
|
return help;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add);
|
|
|
|
static inline int unhelp(struct nf_conntrack_tuple_hash *i,
|
|
const struct nf_conntrack_helper *me)
|
|
{
|
|
struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i);
|
|
struct nf_conn_help *help = nfct_help(ct);
|
|
|
|
if (help && help->helper == me) {
|
|
nf_conntrack_event(IPCT_HELPER, ct);
|
|
rcu_assign_pointer(help->helper, NULL);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
|
|
{
|
|
unsigned int h = helper_hash(&me->tuple);
|
|
|
|
BUG_ON(me->timeout == 0);
|
|
|
|
write_lock_bh(&nf_conntrack_lock);
|
|
hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]);
|
|
nf_ct_helper_count++;
|
|
write_unlock_bh(&nf_conntrack_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_register);
|
|
|
|
void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
|
|
{
|
|
struct nf_conntrack_tuple_hash *h;
|
|
struct nf_conntrack_expect *exp;
|
|
struct hlist_node *n, *next;
|
|
unsigned int i;
|
|
|
|
/* Need write lock here, to delete helper. */
|
|
write_lock_bh(&nf_conntrack_lock);
|
|
hlist_del(&me->hnode);
|
|
nf_ct_helper_count--;
|
|
|
|
/* Get rid of expectations */
|
|
for (i = 0; i < nf_ct_expect_hsize; i++) {
|
|
hlist_for_each_entry_safe(exp, n, next,
|
|
&nf_ct_expect_hash[i], hnode) {
|
|
struct nf_conn_help *help = nfct_help(exp->master);
|
|
if ((help->helper == me || exp->helper == me) &&
|
|
del_timer(&exp->timeout)) {
|
|
nf_ct_unlink_expect(exp);
|
|
nf_ct_expect_put(exp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Get rid of expecteds, set helpers to NULL. */
|
|
hlist_for_each_entry(h, n, &unconfirmed, hnode)
|
|
unhelp(h, me);
|
|
for (i = 0; i < nf_conntrack_htable_size; i++) {
|
|
hlist_for_each_entry(h, n, &nf_conntrack_hash[i], hnode)
|
|
unhelp(h, me);
|
|
}
|
|
write_unlock_bh(&nf_conntrack_lock);
|
|
|
|
/* Someone could be still looking at the helper in a bh. */
|
|
synchronize_net();
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
|
|
|
|
static struct nf_ct_ext_type helper_extend __read_mostly = {
|
|
.len = sizeof(struct nf_conn_help),
|
|
.align = __alignof__(struct nf_conn_help),
|
|
.id = NF_CT_EXT_HELPER,
|
|
};
|
|
|
|
int nf_conntrack_helper_init(void)
|
|
{
|
|
int err;
|
|
|
|
nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
|
|
nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize,
|
|
&nf_ct_helper_vmalloc);
|
|
if (!nf_ct_helper_hash)
|
|
return -ENOMEM;
|
|
|
|
err = nf_ct_extend_register(&helper_extend);
|
|
if (err < 0)
|
|
goto err1;
|
|
|
|
return 0;
|
|
|
|
err1:
|
|
nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
|
|
nf_ct_helper_hsize);
|
|
return err;
|
|
}
|
|
|
|
void nf_conntrack_helper_fini(void)
|
|
{
|
|
nf_ct_extend_unregister(&helper_extend);
|
|
nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
|
|
nf_ct_helper_hsize);
|
|
}
|