--- /dev/null
+/*
+ * (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/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 <asm/atomic.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 = 0;
+ struct nf_acct *cur;
+ char *acct_name;
+
+ if (nlh->nlmsg_flags & NLM_F_DUMP) {
+ return netlink_dump_start(nfnl, skb, nlh, nfnl_acct_dump,
+ NULL, 0);
+ }
+
+ 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)
+ 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;
+ }
+ 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);
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