- 根目录:
- net
- netfilter
- nfnetlink_acct.c
/*
* (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
* (C) 2011 Intra2net AG <http://www.intra2net.com>
*
* 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 (or any later at your option).
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/atomic.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 <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_acct.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
static LIST_HEAD(nfnl_acct_list);
struct nf_acct {
atomic64_t pkts;
atomic64_t bytes;
struct list_head head;
atomic_t refcnt;
char name[NFACCT_NAME_MAX];
struct rcu_head rcu_head;
};
static int
nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb,
const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
struct nf_acct *nfacct, *matching = NULL;
char *acct_name;
if (!tb[NFACCT_NAME])
return -EINVAL;
acct_name = nla_data(tb[NFACCT_NAME]);
list_for_each_entry(nfacct, &nfnl_acct_list, head) {
if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
continue;
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
matching = nfacct;
break;
}
if (matching) {
if (nlh->nlmsg_flags & NLM_F_REPLACE) {
/* reset counters if you request a replacement. */
atomic64_set(&matching->pkts, 0);
atomic64_set(&matching->bytes, 0);
return 0;
}
return -EBUSY;
}
nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL);
if (nfacct == NULL)
return -ENOMEM;
strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
if (tb[NFACCT_BYTES]) {
atomic64_set(&nfacct->bytes,
be64_to_cpu(nla_get_u64(tb[NFACCT_BYTES])));
}
if (tb[NFACCT_PKTS]) {
atomic64_set(&nfacct->pkts,
be64_to_cpu(nla_get_u64(tb[NFACCT_PKTS])));
}
atomic_set(&nfacct->refcnt, 1);
list_add_tail_rcu(&nfacct->head, &nfnl_acct_list);
return 0;
}
static int
nfnl_acct_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
int event, struct nf_acct *acct)
{
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
unsigned int flags = pid ? NLM_F_MULTI : 0;
u64 pkts, bytes;
event |= NFNL_SUBSYS_ACCT << 8;
nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags);
if (nlh == NULL)
goto nlmsg_failure;
nfmsg = nlmsg_data(nlh);
nfmsg->nfgen_family = AF_UNSPEC;
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = 0;
NLA_PUT_STRING(skb, NFACCT_NAME, acct->name);
if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
pkts = atomic64_xchg(&acct->pkts, 0);
bytes = atomic64_xchg(&acct->bytes, 0);
} else {
pkts = atomic64_read(&acct->pkts);
bytes = atomic64_read(&acct->bytes);
}
NLA_PUT_BE64(skb, NFACCT_PKTS, cpu_to_be64(pkts));
NLA_PUT_BE64(skb, NFACCT_BYTES, cpu_to_be64(bytes));
NLA_PUT_BE32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt)));
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 nf_acct *cur, *last;
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_list, head) {
if (last && cur != last)
continue;
if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).pid,
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_get(struct sock *nfnl, struct sk_buff *skb,
const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
int ret = -ENOENT;
struct nf_acct *cur;
char *acct_name;
if (nlh->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
.dump = nfnl_acct_dump,
};
return netlink_dump_start(nfnl, skb, nlh, &c);
}
if (!tb[NFACCT_NAME])
return -EINVAL;
acct_name = nla_data(tb[NFACCT_NAME]);
list_for_each_entry(cur, &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).pid,
nlh->nlmsg_seq,
NFNL_MSG_TYPE(nlh->nlmsg_type),
NFNL_MSG_ACCT_NEW, cur);
if (ret <= 0) {
kfree_skb(skb2);
break;
}
ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid,
MSG_DONTWAIT);
if (ret > 0)
ret = 0;
/* this avoids a loop in nfnetlink. */
return ret == -EAGAIN ? -ENOBUFS : ret;
}
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_find_get. */
if (atomic_dec_and_test(&cur->refcnt)) {
/* We are protected by nfnl mutex. */
list_del_rcu(&cur->head);
kfree_rcu(cur, rcu_head);
} else {
/* still in use, restore reference counter. */
atomic_inc(&cur->refcnt);
ret = -EBUSY;
}
return ret;
}
static int
nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
const struct nlmsghdr *nlh, const struct nlattr * const tb[])
{
char *acct_name;
struct nf_acct *cur;
int ret = -ENOENT;
if (!tb[NFACCT_NAME]) {
list_for_each_entry(cur, &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_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 },
};
static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
[NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy },
[NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy },
[NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
.attr_count = NFACCT_MAX,
.policy = nfnl_acct_policy },
[NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
.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(const char *acct_name)
{
struct nf_acct *cur, *acct = NULL;
rcu_read_lock();
list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
continue;
if (!try_module_get(THIS_MODULE))
goto err;
if (!atomic_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)
{
atomic_dec(&acct->refcnt);
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 int __init nfnl_acct_init(void)
{
int ret;
pr_info("nfnl_acct: registering with nfnetlink.\n");
ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
if (ret < 0) {
pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
goto err_out;
}
return 0;
err_out:
return ret;
}
static void __exit nfnl_acct_exit(void)
{
struct nf_acct *cur, *tmp;
pr_info("nfnl_acct: unregistering from nfnetlink.\n");
nfnetlink_subsys_unregister(&nfnl_acct_subsys);
list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) {
list_del_rcu(&cur->head);
/* We are sure that our objects have no clients at this point,
* it's safe to release them all without checking refcnt. */
kfree_rcu(cur, rcu_head);
}
}
module_init(nfnl_acct_init);
module_exit(nfnl_acct_exit);