// SPDX-License-Identifier: GPL-2.0-or-later
/*
* (C) 2011 Pablo Neira Ayuso <[email protected]>
* (C) 2011 Intra2net AG <https://www.intra2net.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <net/netlink.h>
#include <net/sock.h>
#include <net/netns/generic.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_acct.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <[email protected]>");
MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
struct nf_acct {
atomic64_t pkts;
atomic64_t bytes;
unsigned long flags;
struct list_head head;
refcount_t refcnt;
char name[NFACCT_NAME_MAX];
struct rcu_head rcu_head;
char data[];
};
struct nfacct_filter {
u32 value;
u32 mask;
};
struct nfnl_acct_net {
struct list_head nfnl_acct_list;
};
static unsigned int nfnl_acct_net_id __read_mostly;
static inline struct nfnl_acct_net *nfnl_acct_pernet(struct net *net)
{
return net_generic(net, nfnl_acct_net_id);
}
#define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
#define NFACCT_OVERQUOTA_BIT 2 /* NFACCT_F_OVERQUOTA */
static int nfnl_acct_new(struct sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const tb[])
{
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
struct nf_acct *nfacct, *matching = NULL;
unsigned int size = 0;
char *acct_name;
u32 flags = 0;
if (!tb[NFACCT_NAME])
return -EINVAL;
acct_name = nla_data(tb[NFACCT_NAME]);
if (strlen(acct_name) == 0)
return -EINVAL;
list_for_each_entry(nfacct, &nfnl_acct_net->nfnl_acct_list, head) {
if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
continue;
if (info->nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
matching = nfacct;
break;
}
if (matching) {
if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
/* reset counters if you request a replacement. */
atomic64_set(&matching->pkts, 0);
atomic64_set(&matching->bytes, 0);
smp_mb__before_atomic();
/* reset overquota flag if quota is enabled. */
if ((matching->flags & NFACCT_F_QUOTA))
clear_bit(NFACCT_OVERQUOTA_BIT,
&matching->flags);
return 0;
}
return -EBUSY;
}
if (tb[NFACCT_FLAGS]) {
flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
if (flags & ~NFACCT_F_QUOTA)
return -EOPNOTSUPP;
if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
return -EINVAL;
if (flags & NFACCT_F_OVERQUOTA)
return -EINVAL;
if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
return -EINVAL;
size += sizeof(u64);
}
nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
if (nfacct == NULL)
return -ENOMEM;
if (flags & NFACCT_F_QUOTA) {
u64 *quota = (u64 *)nfacct->data;
*quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
nfacct->flags = flags;
}
nla_strscpy(nfacct->name, tb[NFACCT_NAME], NFACCT_NAME_MAX);
if (tb[NFACCT_BYTES]) {
atomic64_set(&nfacct->bytes,
be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
}
if (tb[NFACCT_PKTS]) {
atomic64_set(&nfacct->pkts,
be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
}
refcount_set(&nfacct->refcnt, 1);
list_add_tail_rcu(&nfacct->head, &nfnl_acct_net->nfnl_acct_list);
return 0;
}
static int
nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
int event, struct nf_acct *acct)
{
struct nlmsghdr *nlh;
unsigned int flags = portid ? NLM_F_MULTI : 0;
u64 pkts, bytes;
u32 old_flags;
event = nfnl_msg_type(NFNL_SUBSYS_ACCT, event);
nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
NFNETLINK_V0, 0);
if (!nlh)
goto nlmsg_failure;
if (nla_put_string(skb, NFACCT_NAME, acct->name))
goto nla_put_failure;
old_flags = acct->flags;
if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
pkts = atomic64_xchg(&acct->pkts, 0);
bytes = atomic64_xchg(&acct->bytes, 0);
smp_mb__before_atomic();
if (acct->flags & NFACCT_F_QUOTA)
clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
} else {
pkts = atomic64_read(&acct->pkts);
bytes = atomic64_read(&acct->bytes);
}
if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts),
NFACCT_PAD) ||
nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes),
NFACCT_PAD) ||
nla_put_be32(skb, NFACCT_USE, htonl(refcount_read(&acct->refcnt))))
goto nla_put_failure;
if (acct->flags & NFACCT_F_QUOTA) {
u64 *quota = (u64 *)acct->data;
if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) ||
nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota),
NFACCT_PAD))
goto nla_put_failure;
}
nlmsg_end(skb, nlh);
return skb->len;
nlmsg_failure:
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -1;
}
static int
nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
struct nf_acct *cur, *last;
const struct nfacct_filter *filter = cb->data;
if (cb->args[2])
return 0;
last = (struct nf_acct *)cb->args[1];
if (cb->args[1])
cb->args[1] = 0;
rcu_read_lock();
list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
if (last) {
if (cur != last)
continue;
last = NULL;
}
if (filter && (cur->flags & filter->mask) != filter->value)
continue;
if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
NFNL_MSG_ACCT_NEW, cur) < 0) {
cb->args[1] = (unsigned long)cur;
break;
}
}
if (!cb->args[1])
cb->args[2] = 1;
rcu_read_unlock();
return skb->len;
}
static int nfnl_acct_done(struct netlink_callback *cb)
{
kfree(cb->data);
return 0;
}
static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
[NFACCT_FILTER_MASK] = { .type = NLA_U32 },
[NFACCT_FILTER_VALUE] = { .type = NLA_U32 },
};
static int nfnl_acct_start(struct netlink_callback *cb)
{
const struct nlattr *const attr = cb->data;
struct nlattr *tb[NFACCT_FILTER_MAX + 1];
struct nfacct_filter *filter;
int err;
if (!attr)
return 0;
err = nla_parse_nested_deprecated(tb, NFACCT_FILTER_MAX, attr,
filter_policy, NULL);
if (err < 0)
return err;
if (!tb[NFACCT_FILTER_MASK] || !tb[NFACCT_FILTER_VALUE])
return -EINVAL;
filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
if (!filter)
return -ENOMEM;
filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
cb->data = filter;
return 0;
}
static int nfnl_acct_get(struct sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const tb[])
{
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
int ret = -ENOENT;
struct nf_acct *cur;
char *acct_name;
if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
.dump = nfnl_acct_dump,
.start = nfnl_acct_start,
.done = nfnl_acct_done,
.data = (void *)tb[NFACCT_FILTER],
};
return netlink_dump_start(info->sk, skb, info->nlh, &c);
}
if (!tb[NFACCT_NAME])
return -EINVAL;
acct_name = nla_data(tb[NFACCT_NAME]);
list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
struct sk_buff *skb2;
if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
continue;
skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (skb2 == NULL) {
ret = -ENOMEM;
break;
}
ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
info->nlh->nlmsg_seq,
NFNL_MSG_TYPE(info->nlh->nlmsg_type),
NFNL_MSG_ACCT_NEW, cur);
if (ret <= 0) {
kfree_skb(skb2);
break;
}
ret = nfnetlink_unicast(skb2, info->net, NETLINK_CB(skb).portid);
break;
}
return ret;
}
/* try to delete object, fail if it is still in use. */
static int nfnl_acct_try_del(struct nf_acct *cur)
{
int ret = 0;
/* We want to avoid races with nfnl_acct_put. So only when the current
* refcnt is 1, we decrease it to 0.
*/
if (refcount_dec_if_one(&cur->refcnt)) {
/* We are protected by nfnl mutex. */
list_del_rcu(&cur->head);
kfree_rcu(cur, rcu_head);
} else {
ret = -EBUSY;
}
return ret;
}
static int nfnl_acct_del(struct sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const tb[])
{
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
struct nf_acct *cur, *tmp;
int ret = -ENOENT;
char *acct_name;
if (!tb[NFACCT_NAME]) {
list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head)
nfnl_acct_try_del(cur);
return 0;
}
acct_name = nla_data(tb[NFACCT_NAME]);
list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
continue;
ret = nfnl_acct_try_del(cur);
if (ret < 0)
return ret;
break;
}
return ret;
}
static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
[NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
[NFACCT_BYTES] = { .type = NLA_U64 },
[NFACCT_PKTS] = { .type = NLA_U64 },
[NFACCT_FLAGS] = { .type = NLA_U32 },
[NFACCT_QUOTA] = { .type = NLA_U64 },
[NFACCT_FILTER] = {.type = NLA_NESTED },
};
static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
[NFNL_MSG_ACCT_NEW] = {
.call = nfnl_acct_new,
.type = NFNL_CB_MUTEX,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy
},
[NFNL_MSG_ACCT_GET] = {
.call = nfnl_acct_get,
.type = NFNL_CB_MUTEX,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy
},
[NFNL_MSG_ACCT_GET_CTRZERO] = {
.call = nfnl_acct_get,
.type = NFNL_CB_MUTEX,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy
},
[NFNL_MSG_ACCT_DEL] = {
.call = nfnl_acct_del,
.type = NFNL_CB_MUTEX,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy
},
};
static const struct nfnetlink_subsystem nfnl_acct_subsys = {
.name = "acct",
.subsys_id = NFNL_SUBSYS_ACCT,
.cb_count = NFNL_MSG_ACCT_MAX,
.cb = nfnl_acct_cb,
};
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
struct nf_acct *nfnl_acct_find_get(struct net *net, const char *acct_name)
{
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
struct nf_acct *cur, *acct = NULL;
rcu_read_lock();
list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
continue;
if (!try_module_get(THIS_MODULE))
goto err;
if (!refcount_inc_not_zero(&cur->refcnt)) {
module_put(THIS_MODULE);
goto err;
}
acct = cur;
break;
}
err:
rcu_read_unlock();
return acct;
}
EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
void nfnl_acct_put(struct nf_acct *acct)
{
if (refcount_dec_and_test(&acct->refcnt))
kfree_rcu(acct, rcu_head);
module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(nfnl_acct_put);
void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
{
atomic64_inc(&nfacct->pkts);
atomic64_add(skb->len, &nfacct->bytes);
}
EXPORT_SYMBOL_GPL(nfnl_acct_update);
static void nfnl_overquota_report(struct net *net, struct nf_acct *nfacct)
{
int ret;
struct sk_buff *skb;
skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
if (skb == NULL)
return;
ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0,
nfacct);
if (ret <= 0) {
kfree_skb(skb);
return;
}
nfnetlink_broadcast(net, skb, 0, NFNLGRP_ACCT_QUOTA, GFP_ATOMIC);
}
int nfnl_acct_overquota(struct net *net, struct nf_acct *nfacct)
{
u64 now;
u64 *quota;
int ret = NFACCT_UNDERQUOTA;
/* no place here if we don't have a quota */
if (!(nfacct->flags & NFACCT_F_QUOTA))
return NFACCT_NO_QUOTA;
quota = (u64 *)nfacct->data;
now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ?
atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes);
ret = now > *quota;
if (now >= *quota &&
!test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) {
nfnl_overquota_report(net, nfacct);
}
return ret;
}
EXPORT_SYMBOL_GPL(nfnl_acct_overquota);
static int __net_init nfnl_acct_net_init(struct net *net)
{
INIT_LIST_HEAD(&nfnl_acct_pernet(net)->nfnl_acct_list);
return 0;
}
static void __net_exit nfnl_acct_net_exit(struct net *net)
{
struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
struct nf_acct *cur, *tmp;
list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head) {
list_del_rcu(&cur->head);
if (refcount_dec_and_test(&cur->refcnt))
kfree_rcu(cur, rcu_head);
}
}
static struct pernet_operations nfnl_acct_ops = {
.init = nfnl_acct_net_init,
.exit = nfnl_acct_net_exit,
.id = &nfnl_acct_net_id,
.size = sizeof(struct nfnl_acct_net),
};
static int __init nfnl_acct_init(void)
{
int ret;
ret = register_pernet_subsys(&nfnl_acct_ops);
if (ret < 0) {
pr_err("nfnl_acct_init: failed to register pernet ops\n");
goto err_out;
}
ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
if (ret < 0) {
pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
goto cleanup_pernet;
}
return 0;
cleanup_pernet:
unregister_pernet_subsys(&nfnl_acct_ops);
err_out:
return ret;
}
static void __exit nfnl_acct_exit(void)
{
nfnetlink_subsys_unregister(&nfnl_acct_subsys);
unregister_pernet_subsys(&nfnl_acct_ops);
}
module_init(nfnl_acct_init);
module_exit(nfnl_acct_exit);
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