1 files changed, 429 insertions, 0 deletions

diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c
new file mode 100644
index 000000000000..fec29a43de4d
--- /dev/null
+++ b/net/netfilter/nfnetlink_cttimeout.c
@@ -0,0 +1,429 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * (C) 2012 by Vyatta Inc. <http://www.vyatta.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/rculist.h>
+#include <linux/rculist_nulls.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/security.h>
+#include <linux/skbuff.h>
+#include <linux/errno.h>
+#include <linux/netlink.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+
+#include <linux/netfilter.h>
+#include <net/netlink.h>
+#include <net/sock.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_l3proto.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_tuple.h>
+#include <net/netfilter/nf_conntrack_timeout.h>
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_cttimeout.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
+MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
+
+static LIST_HEAD(cttimeout_list);
+
+static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
+	[CTA_TIMEOUT_NAME]	= { .type = NLA_NUL_STRING },
+	[CTA_TIMEOUT_L3PROTO]	= { .type = NLA_U16 },
+	[CTA_TIMEOUT_L4PROTO]	= { .type = NLA_U8 },
+	[CTA_TIMEOUT_DATA]	= { .type = NLA_NESTED },
+};
+
+static int
+ctnl_timeout_parse_policy(struct ctnl_timeout *timeout,
+			       struct nf_conntrack_l4proto *l4proto,
+			       const struct nlattr *attr)
+{
+	int ret = 0;
+
+	if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
+		struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
+
+		nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
+				 attr, l4proto->ctnl_timeout.nla_policy);
+
+		ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, &timeout->data);
+	}
+	return ret;
+}
+
+static int
+cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
+		      const struct nlmsghdr *nlh,
+		      const struct nlattr * const cda[])
+{
+	__u16 l3num;
+	__u8 l4num;
+	struct nf_conntrack_l4proto *l4proto;
+	struct ctnl_timeout *timeout, *matching = NULL;
+	char *name;
+	int ret;
+
+	if (!cda[CTA_TIMEOUT_NAME] ||
+	    !cda[CTA_TIMEOUT_L3PROTO] ||
+	    !cda[CTA_TIMEOUT_L4PROTO] ||
+	    !cda[CTA_TIMEOUT_DATA])
+		return -EINVAL;
+
+	name = nla_data(cda[CTA_TIMEOUT_NAME]);
+	l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
+	l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
+
+	list_for_each_entry(timeout, &cttimeout_list, head) {
+		if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
+			continue;
+
+		if (nlh->nlmsg_flags & NLM_F_EXCL)
+			return -EEXIST;
+
+		matching = timeout;
+		break;
+	}
+
+	l4proto = __nf_ct_l4proto_find(l3num, l4num);
+
+	/* This protocol is not supportted, skip. */
+	if (l4proto->l4proto != l4num)
+		return -EOPNOTSUPP;
+
+	if (matching) {
+		if (nlh->nlmsg_flags & NLM_F_REPLACE) {
+			/* You cannot replace one timeout policy by another of
+			 * different kind, sorry.
+			 */
+			if (matching->l3num != l3num ||
+			    matching->l4num != l4num)
+				return -EINVAL;
+
+			ret = ctnl_timeout_parse_policy(matching, l4proto,
+							cda[CTA_TIMEOUT_DATA]);
+			return ret;
+		}
+		return -EBUSY;
+	}
+
+	timeout = kzalloc(sizeof(struct ctnl_timeout) +
+			  l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
+	if (timeout == NULL)
+		return -ENOMEM;
+
+	ret = ctnl_timeout_parse_policy(timeout, l4proto,
+					cda[CTA_TIMEOUT_DATA]);
+	if (ret < 0)
+		goto err;
+
+	strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
+	timeout->l3num = l3num;
+	timeout->l4num = l4num;
+	atomic_set(&timeout->refcnt, 1);
+	list_add_tail_rcu(&timeout->head, &cttimeout_list);
+
+	return 0;
+err:
+	kfree(timeout);
+	return ret;
+}
+
+static int
+ctnl_timeout_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type,
+		       int event, struct ctnl_timeout *timeout)
+{
+	struct nlmsghdr *nlh;
+	struct nfgenmsg *nfmsg;
+	unsigned int flags = pid ? NLM_F_MULTI : 0;
+	struct nf_conntrack_l4proto *l4proto;
+
+	event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 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, CTA_TIMEOUT_NAME, timeout->name);
+	NLA_PUT_BE16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num));
+	NLA_PUT_U8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4num);
+	NLA_PUT_BE32(skb, CTA_TIMEOUT_USE,
+			htonl(atomic_read(&timeout->refcnt)));
+
+	l4proto = __nf_ct_l4proto_find(timeout->l3num, timeout->l4num);
+
+	/* If the timeout object does not match the layer 4 protocol tracker,
+	 * then skip dumping the data part since we don't know how to
+	 * interpret it. This may happen for UPDlite, SCTP and DCCP since
+	 * you can unload the module.
+	 */
+	if (timeout->l4num != l4proto->l4proto)
+		goto out;
+
+	if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
+		struct nlattr *nest_parms;
+		int ret;
+
+		nest_parms = nla_nest_start(skb,
+					    CTA_TIMEOUT_DATA | NLA_F_NESTED);
+		if (!nest_parms)
+			goto nla_put_failure;
+
+		ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
+		if (ret < 0)
+			goto nla_put_failure;
+
+		nla_nest_end(skb, nest_parms);
+	}
+out:
+	nlmsg_end(skb, nlh);
+	return skb->len;
+
+nlmsg_failure:
+nla_put_failure:
+	nlmsg_cancel(skb, nlh);
+	return -1;
+}
+
+static int
+ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct ctnl_timeout *cur, *last;
+
+	if (cb->args[2])
+		return 0;
+
+	last = (struct ctnl_timeout *)cb->args[1];
+	if (cb->args[1])
+		cb->args[1] = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(cur, &cttimeout_list, head) {
+		if (last && cur != last)
+			continue;
+
+		if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).pid,
+					   cb->nlh->nlmsg_seq,
+					   NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
+					   IPCTNL_MSG_TIMEOUT_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
+cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
+		      const struct nlmsghdr *nlh,
+		      const struct nlattr * const cda[])
+{
+	int ret = -ENOENT;
+	char *name;
+	struct ctnl_timeout *cur;
+
+	if (nlh->nlmsg_flags & NLM_F_DUMP) {
+		struct netlink_dump_control c = {
+			.dump = ctnl_timeout_dump,
+		};
+		return netlink_dump_start(ctnl, skb, nlh, &c);
+	}
+
+	if (!cda[CTA_TIMEOUT_NAME])
+		return -EINVAL;
+	name = nla_data(cda[CTA_TIMEOUT_NAME]);
+
+	list_for_each_entry(cur, &cttimeout_list, head) {
+		struct sk_buff *skb2;
+
+		if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
+			continue;
+
+		skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+		if (skb2 == NULL) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).pid,
+					     nlh->nlmsg_seq,
+					     NFNL_MSG_TYPE(nlh->nlmsg_type),
+					     IPCTNL_MSG_TIMEOUT_NEW, cur);
+		if (ret <= 0) {
+			kfree_skb(skb2);
+			break;
+		}
+		ret = netlink_unicast(ctnl, 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 ctnl_timeout_try_del(struct ctnl_timeout *timeout)
+{
+	int ret = 0;
+
+	/* we want to avoid races with nf_ct_timeout_find_get. */
+	if (atomic_dec_and_test(&timeout->refcnt)) {
+		/* We are protected by nfnl mutex. */
+		list_del_rcu(&timeout->head);
+		kfree_rcu(timeout, rcu_head);
+	} else {
+		/* still in use, restore reference counter. */
+		atomic_inc(&timeout->refcnt);
+		ret = -EBUSY;
+	}
+	return ret;
+}
+
+static int
+cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
+		      const struct nlmsghdr *nlh,
+		      const struct nlattr * const cda[])
+{
+	char *name;
+	struct ctnl_timeout *cur;
+	int ret = -ENOENT;
+
+	if (!cda[CTA_TIMEOUT_NAME]) {
+		list_for_each_entry(cur, &cttimeout_list, head)
+			ctnl_timeout_try_del(cur);
+
+		return 0;
+	}
+	name = nla_data(cda[CTA_TIMEOUT_NAME]);
+
+	list_for_each_entry(cur, &cttimeout_list, head) {
+		if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
+			continue;
+
+		ret = ctnl_timeout_try_del(cur);
+		if (ret < 0)
+			return ret;
+
+		break;
+	}
+	return ret;
+}
+
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
+{
+	struct ctnl_timeout *timeout, *matching = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
+		if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
+			continue;
+
+		if (!try_module_get(THIS_MODULE))
+			goto err;
+
+		if (!atomic_inc_not_zero(&timeout->refcnt)) {
+			module_put(THIS_MODULE);
+			goto err;
+		}
+		matching = timeout;
+		break;
+	}
+err:
+	rcu_read_unlock();
+	return matching;
+}
+
+static void ctnl_timeout_put(struct ctnl_timeout *timeout)
+{
+	atomic_dec(&timeout->refcnt);
+	module_put(THIS_MODULE);
+}
+#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
+
+static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
+	[IPCTNL_MSG_TIMEOUT_NEW]	= { .call = cttimeout_new_timeout,
+					    .attr_count = CTA_TIMEOUT_MAX,
+					    .policy = cttimeout_nla_policy },
+	[IPCTNL_MSG_TIMEOUT_GET]	= { .call = cttimeout_get_timeout,
+					    .attr_count = CTA_TIMEOUT_MAX,
+					    .policy = cttimeout_nla_policy },
+	[IPCTNL_MSG_TIMEOUT_DELETE]	= { .call = cttimeout_del_timeout,
+					    .attr_count = CTA_TIMEOUT_MAX,
+					    .policy = cttimeout_nla_policy },
+};
+
+static const struct nfnetlink_subsystem cttimeout_subsys = {
+	.name				= "conntrack_timeout",
+	.subsys_id			= NFNL_SUBSYS_CTNETLINK_TIMEOUT,
+	.cb_count			= IPCTNL_MSG_TIMEOUT_MAX,
+	.cb				= cttimeout_cb,
+};
+
+MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
+
+static int __init cttimeout_init(void)
+{
+	int ret;
+
+	ret = nfnetlink_subsys_register(&cttimeout_subsys);
+	if (ret < 0) {
+		pr_err("cttimeout_init: cannot register cttimeout with "
+			"nfnetlink.\n");
+		goto err_out;
+	}
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
+	RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
+#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
+	return 0;
+
+err_out:
+	return ret;
+}
+
+static void __exit cttimeout_exit(void)
+{
+	struct ctnl_timeout *cur, *tmp;
+
+	pr_info("cttimeout: unregistering from nfnetlink.\n");
+
+	nfnetlink_subsys_unregister(&cttimeout_subsys);
+	list_for_each_entry_safe(cur, tmp, &cttimeout_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);
+	}
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+	RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
+	RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
+#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
+}
+
+module_init(cttimeout_init);
+module_exit(cttimeout_exit);