// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
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* (C) 2011 Intra2net AG <https://www.intra2net.com>
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/atomic.h>
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#include <linux/refcount.h>
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#include <linux/netlink.h>
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#include <linux/rculist.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <net/netlink.h>
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#include <net/sock.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nfnetlink_acct.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
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MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
|
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struct nf_acct {
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atomic64_t pkts;
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atomic64_t bytes;
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unsigned long flags;
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struct list_head head;
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refcount_t refcnt;
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char name[NFACCT_NAME_MAX];
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struct rcu_head rcu_head;
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char data[];
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};
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struct nfacct_filter {
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u32 value;
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u32 mask;
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};
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#define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
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#define NFACCT_OVERQUOTA_BIT 2 /* NFACCT_F_OVERQUOTA */
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static int nfnl_acct_new(struct net *net, struct sock *nfnl,
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struct sk_buff *skb, const struct nlmsghdr *nlh,
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const struct nlattr * const tb[],
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struct netlink_ext_ack *extack)
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{
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struct nf_acct *nfacct, *matching = NULL;
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char *acct_name;
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unsigned int size = 0;
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u32 flags = 0;
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if (!tb[NFACCT_NAME])
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return -EINVAL;
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acct_name = nla_data(tb[NFACCT_NAME]);
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if (strlen(acct_name) == 0)
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return -EINVAL;
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list_for_each_entry(nfacct, &net->nfnl_acct_list, head) {
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if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
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continue;
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if (nlh->nlmsg_flags & NLM_F_EXCL)
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return -EEXIST;
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matching = nfacct;
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break;
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}
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if (matching) {
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if (nlh->nlmsg_flags & NLM_F_REPLACE) {
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/* reset counters if you request a replacement. */
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atomic64_set(&matching->pkts, 0);
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atomic64_set(&matching->bytes, 0);
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smp_mb__before_atomic();
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/* reset overquota flag if quota is enabled. */
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if ((matching->flags & NFACCT_F_QUOTA))
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clear_bit(NFACCT_OVERQUOTA_BIT,
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&matching->flags);
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return 0;
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}
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return -EBUSY;
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}
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if (tb[NFACCT_FLAGS]) {
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flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
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if (flags & ~NFACCT_F_QUOTA)
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return -EOPNOTSUPP;
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if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
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return -EINVAL;
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if (flags & NFACCT_F_OVERQUOTA)
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return -EINVAL;
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if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
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return -EINVAL;
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size += sizeof(u64);
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}
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nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
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if (nfacct == NULL)
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return -ENOMEM;
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if (flags & NFACCT_F_QUOTA) {
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u64 *quota = (u64 *)nfacct->data;
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*quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
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nfacct->flags = flags;
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}
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nla_strlcpy(nfacct->name, tb[NFACCT_NAME], NFACCT_NAME_MAX);
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if (tb[NFACCT_BYTES]) {
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atomic64_set(&nfacct->bytes,
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be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
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}
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if (tb[NFACCT_PKTS]) {
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atomic64_set(&nfacct->pkts,
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be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
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}
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refcount_set(&nfacct->refcnt, 1);
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list_add_tail_rcu(&nfacct->head, &net->nfnl_acct_list);
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return 0;
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}
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static int
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nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
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int event, struct nf_acct *acct)
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{
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struct nlmsghdr *nlh;
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unsigned int flags = portid ? NLM_F_MULTI : 0;
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u64 pkts, bytes;
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u32 old_flags;
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event = nfnl_msg_type(NFNL_SUBSYS_ACCT, event);
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nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
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NFNETLINK_V0, 0);
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if (!nlh)
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goto nlmsg_failure;
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if (nla_put_string(skb, NFACCT_NAME, acct->name))
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goto nla_put_failure;
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old_flags = acct->flags;
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if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
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pkts = atomic64_xchg(&acct->pkts, 0);
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bytes = atomic64_xchg(&acct->bytes, 0);
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smp_mb__before_atomic();
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if (acct->flags & NFACCT_F_QUOTA)
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clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
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} else {
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pkts = atomic64_read(&acct->pkts);
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bytes = atomic64_read(&acct->bytes);
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}
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if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts),
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NFACCT_PAD) ||
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nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes),
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NFACCT_PAD) ||
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nla_put_be32(skb, NFACCT_USE, htonl(refcount_read(&acct->refcnt))))
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goto nla_put_failure;
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if (acct->flags & NFACCT_F_QUOTA) {
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u64 *quota = (u64 *)acct->data;
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if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) ||
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nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota),
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NFACCT_PAD))
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goto nla_put_failure;
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}
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nlmsg_end(skb, nlh);
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return skb->len;
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nlmsg_failure:
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nla_put_failure:
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nlmsg_cancel(skb, nlh);
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return -1;
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}
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static int
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nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct net *net = sock_net(skb->sk);
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struct nf_acct *cur, *last;
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const struct nfacct_filter *filter = cb->data;
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if (cb->args[2])
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return 0;
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last = (struct nf_acct *)cb->args[1];
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if (cb->args[1])
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cb->args[1] = 0;
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rcu_read_lock();
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list_for_each_entry_rcu(cur, &net->nfnl_acct_list, head) {
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if (last) {
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if (cur != last)
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continue;
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last = NULL;
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}
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if (filter && (cur->flags & filter->mask) != filter->value)
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continue;
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if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq,
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NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
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NFNL_MSG_ACCT_NEW, cur) < 0) {
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cb->args[1] = (unsigned long)cur;
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break;
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}
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}
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if (!cb->args[1])
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cb->args[2] = 1;
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rcu_read_unlock();
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return skb->len;
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}
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static int nfnl_acct_done(struct netlink_callback *cb)
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{
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kfree(cb->data);
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return 0;
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}
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static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
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[NFACCT_FILTER_MASK] = { .type = NLA_U32 },
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[NFACCT_FILTER_VALUE] = { .type = NLA_U32 },
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};
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static int nfnl_acct_start(struct netlink_callback *cb)
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{
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const struct nlattr *const attr = cb->data;
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struct nlattr *tb[NFACCT_FILTER_MAX + 1];
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struct nfacct_filter *filter;
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int err;
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if (!attr)
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return 0;
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err = nla_parse_nested_deprecated(tb, NFACCT_FILTER_MAX, attr,
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filter_policy, NULL);
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if (err < 0)
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return err;
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if (!tb[NFACCT_FILTER_MASK] || !tb[NFACCT_FILTER_VALUE])
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return -EINVAL;
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filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
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if (!filter)
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return -ENOMEM;
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filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
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filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
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cb->data = filter;
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return 0;
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}
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static int nfnl_acct_get(struct net *net, struct sock *nfnl,
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struct sk_buff *skb, const struct nlmsghdr *nlh,
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const struct nlattr * const tb[],
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struct netlink_ext_ack *extack)
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{
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int ret = -ENOENT;
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struct nf_acct *cur;
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char *acct_name;
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if (nlh->nlmsg_flags & NLM_F_DUMP) {
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struct netlink_dump_control c = {
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.dump = nfnl_acct_dump,
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.start = nfnl_acct_start,
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.done = nfnl_acct_done,
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.data = (void *)tb[NFACCT_FILTER],
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};
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return netlink_dump_start(nfnl, skb, nlh, &c);
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}
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if (!tb[NFACCT_NAME])
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return -EINVAL;
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acct_name = nla_data(tb[NFACCT_NAME]);
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list_for_each_entry(cur, &net->nfnl_acct_list, head) {
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struct sk_buff *skb2;
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if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
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continue;
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skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
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if (skb2 == NULL) {
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ret = -ENOMEM;
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break;
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}
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ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
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nlh->nlmsg_seq,
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NFNL_MSG_TYPE(nlh->nlmsg_type),
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NFNL_MSG_ACCT_NEW, cur);
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if (ret <= 0) {
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kfree_skb(skb2);
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break;
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}
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ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
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MSG_DONTWAIT);
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if (ret > 0)
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ret = 0;
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/* this avoids a loop in nfnetlink. */
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return ret == -EAGAIN ? -ENOBUFS : ret;
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}
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return ret;
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}
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/* try to delete object, fail if it is still in use. */
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static int nfnl_acct_try_del(struct nf_acct *cur)
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{
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int ret = 0;
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/* We want to avoid races with nfnl_acct_put. So only when the current
|
* refcnt is 1, we decrease it to 0.
|
*/
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if (refcount_dec_if_one(&cur->refcnt)) {
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/* We are protected by nfnl mutex. */
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list_del_rcu(&cur->head);
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kfree_rcu(cur, rcu_head);
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} else {
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ret = -EBUSY;
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}
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return ret;
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}
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static int nfnl_acct_del(struct net *net, struct sock *nfnl,
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struct sk_buff *skb, const struct nlmsghdr *nlh,
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const struct nlattr * const tb[],
|
struct netlink_ext_ack *extack)
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{
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struct nf_acct *cur, *tmp;
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int ret = -ENOENT;
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char *acct_name;
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if (!tb[NFACCT_NAME]) {
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list_for_each_entry_safe(cur, tmp, &net->nfnl_acct_list, head)
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nfnl_acct_try_del(cur);
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return 0;
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}
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acct_name = nla_data(tb[NFACCT_NAME]);
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list_for_each_entry(cur, &net->nfnl_acct_list, head) {
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if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
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continue;
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ret = nfnl_acct_try_del(cur);
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if (ret < 0)
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return ret;
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|
break;
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}
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return ret;
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}
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static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
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[NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
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[NFACCT_BYTES] = { .type = NLA_U64 },
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[NFACCT_PKTS] = { .type = NLA_U64 },
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[NFACCT_FLAGS] = { .type = NLA_U32 },
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[NFACCT_QUOTA] = { .type = NLA_U64 },
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[NFACCT_FILTER] = {.type = NLA_NESTED },
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};
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static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
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[NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
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.attr_count = NFACCT_MAX,
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.policy = nfnl_acct_policy },
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[NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
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.attr_count = NFACCT_MAX,
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.policy = nfnl_acct_policy },
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[NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
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.attr_count = NFACCT_MAX,
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.policy = nfnl_acct_policy },
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[NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
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.attr_count = NFACCT_MAX,
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.policy = nfnl_acct_policy },
|
};
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static const struct nfnetlink_subsystem nfnl_acct_subsys = {
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.name = "acct",
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.subsys_id = NFNL_SUBSYS_ACCT,
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.cb_count = NFNL_MSG_ACCT_MAX,
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.cb = nfnl_acct_cb,
|
};
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|
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
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struct nf_acct *nfnl_acct_find_get(struct net *net, const char *acct_name)
|
{
|
struct nf_acct *cur, *acct = NULL;
|
|
rcu_read_lock();
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list_for_each_entry_rcu(cur, &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;
|
}
|
netlink_broadcast(net->nfnl, 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(&net->nfnl_acct_list);
|
|
return 0;
|
}
|
|
static void __net_exit nfnl_acct_net_exit(struct net *net)
|
{
|
struct nf_acct *cur, *tmp;
|
|
list_for_each_entry_safe(cur, tmp, &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,
|
};
|
|
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);
|
