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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Eric W. Biederman](/assets/img/avatar_default.png)
It is a frequent mistake to confuse the netlink port identifier with a process identifier. Try to reduce this confusion by renaming fields that hold port identifiers portid instead of pid. I have carefully avoided changing the structures exported to userspace to avoid changing the userspace API. I have successfully built an allyesconfig kernel with this change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
365 lines
8.6 KiB
C
365 lines
8.6 KiB
C
/*
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* (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
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* (C) 2011 Intra2net AG <http://www.intra2net.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation (or any later at your option).
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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/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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static LIST_HEAD(nfnl_acct_list);
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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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struct list_head head;
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atomic_t refcnt;
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char name[NFACCT_NAME_MAX];
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struct rcu_head rcu_head;
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};
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static int
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nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb,
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const struct nlmsghdr *nlh, const struct nlattr * const tb[])
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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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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(nfacct, &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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return 0;
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}
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return -EBUSY;
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}
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nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL);
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if (nfacct == NULL)
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return -ENOMEM;
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strncpy(nfacct->name, nla_data(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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atomic_set(&nfacct->refcnt, 1);
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list_add_tail_rcu(&nfacct->head, &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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struct nfgenmsg *nfmsg;
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unsigned int flags = portid ? NLM_F_MULTI : 0;
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u64 pkts, bytes;
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event |= NFNL_SUBSYS_ACCT << 8;
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nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
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if (nlh == NULL)
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goto nlmsg_failure;
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nfmsg = nlmsg_data(nlh);
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nfmsg->nfgen_family = AF_UNSPEC;
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nfmsg->version = NFNETLINK_V0;
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nfmsg->res_id = 0;
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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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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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} 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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nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) ||
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nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))))
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goto nla_put_failure;
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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 nf_acct *cur, *last;
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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, &nfnl_acct_list, head) {
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if (last && cur != last)
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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
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nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
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const struct nlmsghdr *nlh, const struct nlattr * const tb[])
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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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};
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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, &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_find_get. */
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if (atomic_dec_and_test(&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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/* still in use, restore reference counter. */
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atomic_inc(&cur->refcnt);
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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
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nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
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const struct nlmsghdr *nlh, const struct nlattr * const tb[])
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{
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char *acct_name;
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struct nf_acct *cur;
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int ret = -ENOENT;
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if (!tb[NFACCT_NAME]) {
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list_for_each_entry(cur, &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, &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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};
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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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};
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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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};
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MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
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struct nf_acct *nfnl_acct_find_get(const char *acct_name)
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{
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struct nf_acct *cur, *acct = NULL;
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rcu_read_lock();
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list_for_each_entry_rcu(cur, &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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if (!try_module_get(THIS_MODULE))
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goto err;
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if (!atomic_inc_not_zero(&cur->refcnt)) {
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module_put(THIS_MODULE);
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goto err;
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}
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acct = cur;
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break;
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}
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err:
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rcu_read_unlock();
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return acct;
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}
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EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
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void nfnl_acct_put(struct nf_acct *acct)
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{
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atomic_dec(&acct->refcnt);
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module_put(THIS_MODULE);
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}
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EXPORT_SYMBOL_GPL(nfnl_acct_put);
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void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
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{
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atomic64_inc(&nfacct->pkts);
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atomic64_add(skb->len, &nfacct->bytes);
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}
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EXPORT_SYMBOL_GPL(nfnl_acct_update);
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static int __init nfnl_acct_init(void)
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{
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int ret;
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pr_info("nfnl_acct: registering with nfnetlink.\n");
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ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
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if (ret < 0) {
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pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
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goto err_out;
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}
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return 0;
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err_out:
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return ret;
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}
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static void __exit nfnl_acct_exit(void)
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{
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struct nf_acct *cur, *tmp;
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pr_info("nfnl_acct: unregistering from nfnetlink.\n");
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nfnetlink_subsys_unregister(&nfnl_acct_subsys);
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list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) {
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list_del_rcu(&cur->head);
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/* We are sure that our objects have no clients at this point,
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* it's safe to release them all without checking refcnt. */
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kfree_rcu(cur, rcu_head);
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}
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}
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module_init(nfnl_acct_init);
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module_exit(nfnl_acct_exit);
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