Initial import

1 files changed, 512 insertions, 0 deletions

diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c
new file mode 100644
index 000000000..c18af2f63
--- /dev/null
+++ b/net/netfilter/nfnetlink_acct.c
@@ -0,0 +1,512 @@
+/*
+ * (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;
+	unsigned long		flags;
+	struct list_head	head;
+	atomic_t		refcnt;
+	char			name[NFACCT_NAME_MAX];
+	struct rcu_head		rcu_head;
+	char			data[0];
+};
+
+struct nfacct_filter {
+	u32 value;
+	u32 mask;
+};
+
+#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 sock *nfnl, struct sk_buff *skb,
+	     const struct nlmsghdr *nlh, const struct nlattr * const tb[])
+{
+	struct nf_acct *nfacct, *matching = NULL;
+	char *acct_name;
+	unsigned int size = 0;
+	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_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);
+			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;
+
+		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;
+	}
+
+	strncpy(nfacct->name, nla_data(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])));
+	}
+	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 portid, u32 seq, u32 type,
+		   int event, struct nf_acct *acct)
+{
+	struct nlmsghdr *nlh;
+	struct nfgenmsg *nfmsg;
+	unsigned int flags = portid ? NLM_F_MULTI : 0;
+	u64 pkts, bytes;
+	u32 old_flags;
+
+	event |= NFNL_SUBSYS_ACCT << 8;
+	nlh = nlmsg_put(skb, portid, 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;
+
+	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)) ||
+	    nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) ||
+	    nla_put_be32(skb, NFACCT_USE, htonl(atomic_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)))
+			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 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_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 struct nfacct_filter *
+nfacct_filter_alloc(const struct nlattr * const attr)
+{
+	struct nfacct_filter *filter;
+	struct nlattr *tb[NFACCT_FILTER_MAX + 1];
+	int err;
+
+	err = nla_parse_nested(tb, NFACCT_FILTER_MAX, attr, filter_policy);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
+	if (!filter)
+		return ERR_PTR(-ENOMEM);
+
+	filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
+	filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
+
+	return filter;
+}
+
+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,
+			.done = nfnl_acct_done,
+		};
+
+		if (tb[NFACCT_FILTER]) {
+			struct nfacct_filter *filter;
+
+			filter = nfacct_filter_alloc(tb[NFACCT_FILTER]);
+			if (IS_ERR(filter))
+				return PTR_ERR(filter);
+
+			c.data = filter;
+		}
+		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).portid,
+					 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).portid,
+					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 },
+	[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,
+					    .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 void nfnl_overquota_report(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(init_net.nfnl, skb, 0, NFNLGRP_ACCT_QUOTA,
+			  GFP_ATOMIC);
+}
+
+int nfnl_acct_overquota(const struct sk_buff *skb, 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(nfacct);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nfnl_acct_overquota);
+
+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);