mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Xin Long](/assets/img/avatar_default.png)
Similar to nf_nat_ovs created by Commit ebddb14049
("net: move the
nat function to nf_nat_ovs for ovs and tc"), this patch is to create
nf_conntrack_ovs to get these functions shared by OVS and TC only.
There are nf_ct_helper() and nf_ct_add_helper() from nf_conntrak_helper
in this patch, and will be more in the following patches.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
518 lines
13 KiB
C
518 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* 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>
|
|
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
|
|
*/
|
|
|
|
#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/random.h>
|
|
#include <linux/err.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/rtnetlink.h>
|
|
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_core.h>
|
|
#include <net/netfilter/nf_conntrack_ecache.h>
|
|
#include <net/netfilter/nf_conntrack_extend.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_l4proto.h>
|
|
#include <net/netfilter/nf_conntrack_seqadj.h>
|
|
#include <net/netfilter/nf_log.h>
|
|
#include <net/ip.h>
|
|
|
|
static DEFINE_MUTEX(nf_ct_helper_mutex);
|
|
struct hlist_head *nf_ct_helper_hash __read_mostly;
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_hash);
|
|
unsigned int nf_ct_helper_hsize __read_mostly;
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_hsize);
|
|
static unsigned int nf_ct_helper_count __read_mostly;
|
|
|
|
static DEFINE_MUTEX(nf_ct_nat_helpers_mutex);
|
|
static struct list_head nf_ct_nat_helpers __read_mostly;
|
|
|
|
/* 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) ^
|
|
(__force __u16)tuple->src.u.all) % nf_ct_helper_hsize;
|
|
}
|
|
|
|
struct nf_conntrack_helper *
|
|
__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < nf_ct_helper_hsize; i++) {
|
|
hlist_for_each_entry_rcu(h, &nf_ct_helper_hash[i], hnode) {
|
|
if (strcmp(h->name, name))
|
|
continue;
|
|
|
|
if (h->tuple.src.l3num != NFPROTO_UNSPEC &&
|
|
h->tuple.src.l3num != l3num)
|
|
continue;
|
|
|
|
if (h->tuple.dst.protonum == protonum)
|
|
return h;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find);
|
|
|
|
struct nf_conntrack_helper *
|
|
nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
|
|
rcu_read_lock();
|
|
|
|
h = __nf_conntrack_helper_find(name, l3num, protonum);
|
|
#ifdef CONFIG_MODULES
|
|
if (h == NULL) {
|
|
rcu_read_unlock();
|
|
if (request_module("nfct-helper-%s", name) == 0) {
|
|
rcu_read_lock();
|
|
h = __nf_conntrack_helper_find(name, l3num, protonum);
|
|
} else {
|
|
return h;
|
|
}
|
|
}
|
|
#endif
|
|
if (h != NULL && !try_module_get(h->me))
|
|
h = NULL;
|
|
if (h != NULL && !refcount_inc_not_zero(&h->refcnt)) {
|
|
module_put(h->me);
|
|
h = NULL;
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
return h;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get);
|
|
|
|
void nf_conntrack_helper_put(struct nf_conntrack_helper *helper)
|
|
{
|
|
refcount_dec(&helper->refcnt);
|
|
module_put(helper->me);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_put);
|
|
|
|
static struct nf_conntrack_nat_helper *
|
|
nf_conntrack_nat_helper_find(const char *mod_name)
|
|
{
|
|
struct nf_conntrack_nat_helper *cur;
|
|
bool found = false;
|
|
|
|
list_for_each_entry_rcu(cur, &nf_ct_nat_helpers, list) {
|
|
if (!strcmp(cur->mod_name, mod_name)) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
return found ? cur : NULL;
|
|
}
|
|
|
|
int
|
|
nf_nat_helper_try_module_get(const char *name, u16 l3num, u8 protonum)
|
|
{
|
|
struct nf_conntrack_helper *h;
|
|
struct nf_conntrack_nat_helper *nat;
|
|
char mod_name[NF_CT_HELPER_NAME_LEN];
|
|
int ret = 0;
|
|
|
|
rcu_read_lock();
|
|
h = __nf_conntrack_helper_find(name, l3num, protonum);
|
|
if (!h) {
|
|
rcu_read_unlock();
|
|
return -ENOENT;
|
|
}
|
|
|
|
nat = nf_conntrack_nat_helper_find(h->nat_mod_name);
|
|
if (!nat) {
|
|
snprintf(mod_name, sizeof(mod_name), "%s", h->nat_mod_name);
|
|
rcu_read_unlock();
|
|
request_module("%s", mod_name);
|
|
|
|
rcu_read_lock();
|
|
nat = nf_conntrack_nat_helper_find(mod_name);
|
|
if (!nat) {
|
|
rcu_read_unlock();
|
|
return -ENOENT;
|
|
}
|
|
}
|
|
|
|
if (!try_module_get(nat->module))
|
|
ret = -ENOENT;
|
|
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_nat_helper_try_module_get);
|
|
|
|
void nf_nat_helper_put(struct nf_conntrack_helper *helper)
|
|
{
|
|
struct nf_conntrack_nat_helper *nat;
|
|
|
|
nat = nf_conntrack_nat_helper_find(helper->nat_mod_name);
|
|
if (WARN_ON_ONCE(!nat))
|
|
return;
|
|
|
|
module_put(nat->module);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_nat_helper_put);
|
|
|
|
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);
|
|
|
|
int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
|
|
gfp_t flags)
|
|
{
|
|
struct nf_conntrack_helper *helper = NULL;
|
|
struct nf_conn_help *help;
|
|
|
|
/* We already got a helper explicitly attached. The function
|
|
* nf_conntrack_alter_reply - in case NAT is in use - asks for looking
|
|
* the helper up again. Since now the user is in full control of
|
|
* making consistent helper configurations, skip this automatic
|
|
* re-lookup, otherwise we'll lose the helper.
|
|
*/
|
|
if (test_bit(IPS_HELPER_BIT, &ct->status))
|
|
return 0;
|
|
|
|
if (WARN_ON_ONCE(!tmpl))
|
|
return 0;
|
|
|
|
help = nfct_help(tmpl);
|
|
if (help != NULL) {
|
|
helper = rcu_dereference(help->helper);
|
|
set_bit(IPS_HELPER_BIT, &ct->status);
|
|
}
|
|
|
|
help = nfct_help(ct);
|
|
|
|
if (helper == NULL) {
|
|
if (help)
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
return 0;
|
|
}
|
|
|
|
if (help == NULL) {
|
|
help = nf_ct_helper_ext_add(ct, flags);
|
|
if (help == NULL)
|
|
return -ENOMEM;
|
|
} else {
|
|
/* We only allow helper re-assignment of the same sort since
|
|
* we cannot reallocate the helper extension area.
|
|
*/
|
|
struct nf_conntrack_helper *tmp = rcu_dereference(help->helper);
|
|
|
|
if (tmp && tmp->help != helper->help) {
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
rcu_assign_pointer(help->helper, helper);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper);
|
|
|
|
/* appropriate ct lock protecting must be taken by caller */
|
|
static int unhelp(struct nf_conn *ct, void *me)
|
|
{
|
|
struct nf_conn_help *help = nfct_help(ct);
|
|
|
|
if (help && rcu_dereference_raw(help->helper) == me) {
|
|
nf_conntrack_event(IPCT_HELPER, ct);
|
|
RCU_INIT_POINTER(help->helper, NULL);
|
|
}
|
|
|
|
/* We are not intended to delete this conntrack. */
|
|
return 0;
|
|
}
|
|
|
|
void nf_ct_helper_destroy(struct nf_conn *ct)
|
|
{
|
|
struct nf_conn_help *help = nfct_help(ct);
|
|
struct nf_conntrack_helper *helper;
|
|
|
|
if (help) {
|
|
rcu_read_lock();
|
|
helper = rcu_dereference(help->helper);
|
|
if (helper && helper->destroy)
|
|
helper->destroy(ct);
|
|
rcu_read_unlock();
|
|
}
|
|
}
|
|
|
|
static LIST_HEAD(nf_ct_helper_expectfn_list);
|
|
|
|
void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n)
|
|
{
|
|
spin_lock_bh(&nf_conntrack_expect_lock);
|
|
list_add_rcu(&n->head, &nf_ct_helper_expectfn_list);
|
|
spin_unlock_bh(&nf_conntrack_expect_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_register);
|
|
|
|
void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n)
|
|
{
|
|
spin_lock_bh(&nf_conntrack_expect_lock);
|
|
list_del_rcu(&n->head);
|
|
spin_unlock_bh(&nf_conntrack_expect_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister);
|
|
|
|
/* Caller should hold the rcu lock */
|
|
struct nf_ct_helper_expectfn *
|
|
nf_ct_helper_expectfn_find_by_name(const char *name)
|
|
{
|
|
struct nf_ct_helper_expectfn *cur;
|
|
bool found = false;
|
|
|
|
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
|
|
if (!strcmp(cur->name, name)) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
return found ? cur : NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name);
|
|
|
|
/* Caller should hold the rcu lock */
|
|
struct nf_ct_helper_expectfn *
|
|
nf_ct_helper_expectfn_find_by_symbol(const void *symbol)
|
|
{
|
|
struct nf_ct_helper_expectfn *cur;
|
|
bool found = false;
|
|
|
|
list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) {
|
|
if (cur->expectfn == symbol) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
return found ? cur : NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol);
|
|
|
|
__printf(3, 4)
|
|
void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
|
|
const char *fmt, ...)
|
|
{
|
|
const struct nf_conn_help *help;
|
|
const struct nf_conntrack_helper *helper;
|
|
struct va_format vaf;
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
|
|
vaf.fmt = fmt;
|
|
vaf.va = &args;
|
|
|
|
/* Called from the helper function, this call never fails */
|
|
help = nfct_help(ct);
|
|
|
|
/* rcu_read_lock()ed by nf_hook_thresh */
|
|
helper = rcu_dereference(help->helper);
|
|
|
|
nf_log_packet(nf_ct_net(ct), nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL,
|
|
"nf_ct_%s: dropping packet: %pV ", helper->name, &vaf);
|
|
|
|
va_end(args);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_log);
|
|
|
|
int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
|
|
{
|
|
struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) };
|
|
unsigned int h = helper_hash(&me->tuple);
|
|
struct nf_conntrack_helper *cur;
|
|
int ret = 0, i;
|
|
|
|
BUG_ON(me->expect_policy == NULL);
|
|
BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES);
|
|
BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1);
|
|
|
|
if (me->expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&nf_ct_helper_mutex);
|
|
for (i = 0; i < nf_ct_helper_hsize; i++) {
|
|
hlist_for_each_entry(cur, &nf_ct_helper_hash[i], hnode) {
|
|
if (!strcmp(cur->name, me->name) &&
|
|
(cur->tuple.src.l3num == NFPROTO_UNSPEC ||
|
|
cur->tuple.src.l3num == me->tuple.src.l3num) &&
|
|
cur->tuple.dst.protonum == me->tuple.dst.protonum) {
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* avoid unpredictable behaviour for auto_assign_helper */
|
|
if (!(me->flags & NF_CT_HELPER_F_USERSPACE)) {
|
|
hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) {
|
|
if (nf_ct_tuple_src_mask_cmp(&cur->tuple, &me->tuple,
|
|
&mask)) {
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
refcount_set(&me->refcnt, 1);
|
|
hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
|
|
nf_ct_helper_count++;
|
|
out:
|
|
mutex_unlock(&nf_ct_helper_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_register);
|
|
|
|
static bool expect_iter_me(struct nf_conntrack_expect *exp, void *data)
|
|
{
|
|
struct nf_conn_help *help = nfct_help(exp->master);
|
|
const struct nf_conntrack_helper *me = data;
|
|
const struct nf_conntrack_helper *this;
|
|
|
|
if (exp->helper == me)
|
|
return true;
|
|
|
|
this = rcu_dereference_protected(help->helper,
|
|
lockdep_is_held(&nf_conntrack_expect_lock));
|
|
return this == me;
|
|
}
|
|
|
|
void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
|
|
{
|
|
mutex_lock(&nf_ct_helper_mutex);
|
|
hlist_del_rcu(&me->hnode);
|
|
nf_ct_helper_count--;
|
|
mutex_unlock(&nf_ct_helper_mutex);
|
|
|
|
/* Make sure every nothing is still using the helper unless its a
|
|
* connection in the hash.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
nf_ct_expect_iterate_destroy(expect_iter_me, NULL);
|
|
nf_ct_iterate_destroy(unhelp, me);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
|
|
|
|
void nf_ct_helper_init(struct nf_conntrack_helper *helper,
|
|
u16 l3num, u16 protonum, const char *name,
|
|
u16 default_port, u16 spec_port, u32 id,
|
|
const struct nf_conntrack_expect_policy *exp_pol,
|
|
u32 expect_class_max,
|
|
int (*help)(struct sk_buff *skb, unsigned int protoff,
|
|
struct nf_conn *ct,
|
|
enum ip_conntrack_info ctinfo),
|
|
int (*from_nlattr)(struct nlattr *attr,
|
|
struct nf_conn *ct),
|
|
struct module *module)
|
|
{
|
|
helper->tuple.src.l3num = l3num;
|
|
helper->tuple.dst.protonum = protonum;
|
|
helper->tuple.src.u.all = htons(spec_port);
|
|
helper->expect_policy = exp_pol;
|
|
helper->expect_class_max = expect_class_max;
|
|
helper->help = help;
|
|
helper->from_nlattr = from_nlattr;
|
|
helper->me = module;
|
|
snprintf(helper->nat_mod_name, sizeof(helper->nat_mod_name),
|
|
NF_NAT_HELPER_PREFIX "%s", name);
|
|
|
|
if (spec_port == default_port)
|
|
snprintf(helper->name, sizeof(helper->name), "%s", name);
|
|
else
|
|
snprintf(helper->name, sizeof(helper->name), "%s-%u", name, id);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ct_helper_init);
|
|
|
|
int nf_conntrack_helpers_register(struct nf_conntrack_helper *helper,
|
|
unsigned int n)
|
|
{
|
|
unsigned int i;
|
|
int err = 0;
|
|
|
|
for (i = 0; i < n; i++) {
|
|
err = nf_conntrack_helper_register(&helper[i]);
|
|
if (err < 0)
|
|
goto err;
|
|
}
|
|
|
|
return err;
|
|
err:
|
|
if (i > 0)
|
|
nf_conntrack_helpers_unregister(helper, i);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helpers_register);
|
|
|
|
void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *helper,
|
|
unsigned int n)
|
|
{
|
|
while (n-- > 0)
|
|
nf_conntrack_helper_unregister(&helper[n]);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_conntrack_helpers_unregister);
|
|
|
|
void nf_nat_helper_register(struct nf_conntrack_nat_helper *nat)
|
|
{
|
|
mutex_lock(&nf_ct_nat_helpers_mutex);
|
|
list_add_rcu(&nat->list, &nf_ct_nat_helpers);
|
|
mutex_unlock(&nf_ct_nat_helpers_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_nat_helper_register);
|
|
|
|
void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat)
|
|
{
|
|
mutex_lock(&nf_ct_nat_helpers_mutex);
|
|
list_del_rcu(&nat->list);
|
|
mutex_unlock(&nf_ct_nat_helpers_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_nat_helper_unregister);
|
|
|
|
int nf_conntrack_helper_init(void)
|
|
{
|
|
nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
|
|
nf_ct_helper_hash =
|
|
nf_ct_alloc_hashtable(&nf_ct_helper_hsize, 0);
|
|
if (!nf_ct_helper_hash)
|
|
return -ENOMEM;
|
|
|
|
INIT_LIST_HEAD(&nf_ct_nat_helpers);
|
|
return 0;
|
|
}
|
|
|
|
void nf_conntrack_helper_fini(void)
|
|
{
|
|
kvfree(nf_ct_helper_hash);
|
|
}
|