net/sched/act_mirred.c - third_party/linux - Git at Google

 /*
  * net/sched/act_mirred.c	packet mirroring and redirect actions
  *
  *		This program is free software; you can redistribute it and/or
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
  *
  * Authors:	Jamal Hadi Salim (2002-4)
  *
  * TODO: Add ingress support (and socket redirect support)
  *
  */

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/rtnetlink.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/gfp.h>
 #include <net/net_namespace.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <linux/tc_act/tc_mirred.h>
 #include <net/tc_act/tc_mirred.h>

 #include <linux/if_arp.h>

 #define MIRRED_TAB_MASK     7
 static LIST_HEAD(mirred_list);
 static DEFINE_SPINLOCK(mirred_list_lock);

 static void tcf_mirred_release(struct tc_action *a, int bind)
 {
 	struct tcf_mirred *m = to_mirred(a);
 	struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1);

 	/* We could be called either in a RCU callback or with RTNL lock held. */
 	spin_lock_bh(&mirred_list_lock);
 	list_del(&m->tcfm_list);
 	spin_unlock_bh(&mirred_list_lock);
 	if (dev)
 		dev_put(dev);
 }

 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
 	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
 };

 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 			   struct nlattr *est, struct tc_action *a, int ovr,
 			   int bind)
 {
 	struct nlattr *tb[TCA_MIRRED_MAX + 1];
 	struct tc_mirred *parm;
 	struct tcf_mirred *m;
 	struct net_device *dev;
 	int ret, ok_push = 0;

 	if (nla == NULL)
 		return -EINVAL;
 	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
 	if (ret < 0)
 		return ret;
 	if (tb[TCA_MIRRED_PARMS] == NULL)
 		return -EINVAL;
 	parm = nla_data(tb[TCA_MIRRED_PARMS]);
 	switch (parm->eaction) {
 	case TCA_EGRESS_MIRROR:
 	case TCA_EGRESS_REDIR:
 		break;
 	default:
 		return -EINVAL;
 	}
 	if (parm->ifindex) {
 		dev = __dev_get_by_index(net, parm->ifindex);
 		if (dev == NULL)
 			return -ENODEV;
 		switch (dev->type) {
 		case ARPHRD_TUNNEL:
 		case ARPHRD_TUNNEL6:
 		case ARPHRD_SIT:
 		case ARPHRD_IPGRE:
 		case ARPHRD_VOID:
 		case ARPHRD_NONE:
 			ok_push = 0;
 			break;
 		default:
 			ok_push = 1;
 			break;
 		}
 	} else {
 		dev = NULL;
 	}

 	if (!tcf_hash_check(parm->index, a, bind)) {
 		if (dev == NULL)
 			return -EINVAL;
 		ret = tcf_hash_create(parm->index, est, a, sizeof(*m),
 				      bind, true);
 		if (ret)
 			return ret;
 		ret = ACT_P_CREATED;
 	} else {
 		if (bind)
 			return 0;

 		tcf_hash_release(a, bind);
 		if (!ovr)
 			return -EEXIST;
 	}
 	m = to_mirred(a);

 	ASSERT_RTNL();
 	m->tcf_action = parm->action;
 	m->tcfm_eaction = parm->eaction;
 	if (dev != NULL) {
 		m->tcfm_ifindex = parm->ifindex;
 		if (ret != ACT_P_CREATED)
 			dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
 		dev_hold(dev);
 		rcu_assign_pointer(m->tcfm_dev, dev);
 		m->tcfm_ok_push = ok_push;
 	}

 	if (ret == ACT_P_CREATED) {
 		spin_lock_bh(&mirred_list_lock);
 		list_add(&m->tcfm_list, &mirred_list);
 		spin_unlock_bh(&mirred_list_lock);
 		tcf_hash_insert(a);
 	}

 	return ret;
 }

 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 		      struct tcf_result *res)
 {
 	struct tcf_mirred *m = a->priv;
 	struct net_device *dev;
 	struct sk_buff *skb2;
 	int retval, err;
 	u32 at;

 	tcf_lastuse_update(&m->tcf_tm);

 	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);

 	rcu_read_lock();
 	retval = READ_ONCE(m->tcf_action);
 	dev = rcu_dereference(m->tcfm_dev);
 	if (unlikely(!dev)) {
 		pr_notice_once("tc mirred: target device is gone\n");
 		goto out;
 	}

 	if (unlikely(!(dev->flags & IFF_UP))) {
 		net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 				       dev->name);
 		goto out;
 	}

 	at = G_TC_AT(skb->tc_verd);
 	skb2 = skb_clone(skb, GFP_ATOMIC);
 	if (!skb2)
 		goto out;

 	if (!(at & AT_EGRESS)) {
 		if (m->tcfm_ok_push)
 			skb_push(skb2, skb->mac_len);
 	}

 	/* mirror is always swallowed */
 	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 		skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);

 	skb2->skb_iif = skb->dev->ifindex;
 	skb2->dev = dev;
 	skb_sender_cpu_clear(skb2);
 	err = dev_queue_xmit(skb2);

 	if (err) {
 out:
 		qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
 		if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 			retval = TC_ACT_SHOT;
 	}
 	rcu_read_unlock();

 	return retval;
 }

 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 {
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tcf_mirred *m = a->priv;
 	struct tc_mirred opt = {
 		.index   = m->tcf_index,
 		.action  = m->tcf_action,
 		.refcnt  = m->tcf_refcnt - ref,
 		.bindcnt = m->tcf_bindcnt - bind,
 		.eaction = m->tcfm_eaction,
 		.ifindex = m->tcfm_ifindex,
 	};
 	struct tcf_t t;

 	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 	if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
 		goto nla_put_failure;
 	return skb->len;

 nla_put_failure:
 	nlmsg_trim(skb, b);
 	return -1;
 }

 static int mirred_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct tcf_mirred *m;

 	ASSERT_RTNL();
 	if (event == NETDEV_UNREGISTER) {
 		spin_lock_bh(&mirred_list_lock);
 		list_for_each_entry(m, &mirred_list, tcfm_list) {
 			if (rcu_access_pointer(m->tcfm_dev) == dev) {
 				dev_put(dev);
 				/* Note : no rcu grace period necessary, as
 				 * net_device are already rcu protected.
 				 */
 				RCU_INIT_POINTER(m->tcfm_dev, NULL);
 			}
 		}
 		spin_unlock_bh(&mirred_list_lock);
 	}

 	return NOTIFY_DONE;
 }

 static struct notifier_block mirred_device_notifier = {
 	.notifier_call = mirred_device_event,
 };

 static struct tc_action_ops act_mirred_ops = {
 	.kind		=	"mirred",
 	.type		=	TCA_ACT_MIRRED,
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_mirred,
 	.dump		=	tcf_mirred_dump,
 	.cleanup	=	tcf_mirred_release,
 	.init		=	tcf_mirred_init,
 };

 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 MODULE_LICENSE("GPL");

 static int __init mirred_init_module(void)
 {
 	int err = register_netdevice_notifier(&mirred_device_notifier);
 	if (err)
 		return err;

 	pr_info("Mirror/redirect action on\n");
 	return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
 }

 static void __exit mirred_cleanup_module(void)
 {
 	tcf_unregister_action(&act_mirred_ops);
 	unregister_netdevice_notifier(&mirred_device_notifier);
 }

 module_init(mirred_init_module);
 module_exit(mirred_cleanup_module);
	/*
	* net/sched/act_mirred.c packet mirroring and redirect actions
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*
	* Authors: Jamal Hadi Salim (2002-4)
	*
	* TODO: Add ingress support (and socket redirect support)
	*
	*/

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/errno.h>
	#include <linux/skbuff.h>
	#include <linux/rtnetlink.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/gfp.h>
	#include <net/net_namespace.h>
	#include <net/netlink.h>
	#include <net/pkt_sched.h>
	#include <linux/tc_act/tc_mirred.h>
	#include <net/tc_act/tc_mirred.h>

	#include <linux/if_arp.h>

	#define MIRRED_TAB_MASK 7
	static LIST_HEAD(mirred_list);
	static DEFINE_SPINLOCK(mirred_list_lock);

	static void tcf_mirred_release(struct tc_action *a, int bind)
	{
	struct tcf_mirred *m = to_mirred(a);
	struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1);

	/* We could be called either in a RCU callback or with RTNL lock held. */
	spin_lock_bh(&mirred_list_lock);
	list_del(&m->tcfm_list);
	spin_unlock_bh(&mirred_list_lock);
	if (dev)
	dev_put(dev);
	}

	static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
	[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
	};

	static int tcf_mirred_init(struct net net, struct nlattr nla,
	struct nlattr est, struct tc_action a, int ovr,
	int bind)
	{
	struct nlattr *tb[TCA_MIRRED_MAX + 1];
	struct tc_mirred *parm;
	struct tcf_mirred *m;
	struct net_device *dev;
	int ret, ok_push = 0;

	if (nla == NULL)
	return -EINVAL;
	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
	if (ret < 0)
	return ret;
	if (tb[TCA_MIRRED_PARMS] == NULL)
	return -EINVAL;
	parm = nla_data(tb[TCA_MIRRED_PARMS]);
	switch (parm->eaction) {
	case TCA_EGRESS_MIRROR:
	case TCA_EGRESS_REDIR:
	break;
	default:
	return -EINVAL;
	}
	if (parm->ifindex) {
	dev = __dev_get_by_index(net, parm->ifindex);
	if (dev == NULL)
	return -ENODEV;
	switch (dev->type) {
	case ARPHRD_TUNNEL:
	case ARPHRD_TUNNEL6:
	case ARPHRD_SIT:
	case ARPHRD_IPGRE:
	case ARPHRD_VOID:
	case ARPHRD_NONE:
	ok_push = 0;
	break;
	default:
	ok_push = 1;
	break;
	}
	} else {
	dev = NULL;
	}

	if (!tcf_hash_check(parm->index, a, bind)) {
	if (dev == NULL)
	return -EINVAL;
	ret = tcf_hash_create(parm->index, est, a, sizeof(*m),
	bind, true);
	if (ret)
	return ret;
	ret = ACT_P_CREATED;
	} else {
	if (bind)
	return 0;

	tcf_hash_release(a, bind);
	if (!ovr)
	return -EEXIST;
	}
	m = to_mirred(a);

	ASSERT_RTNL();
	m->tcf_action = parm->action;
	m->tcfm_eaction = parm->eaction;
	if (dev != NULL) {
	m->tcfm_ifindex = parm->ifindex;
	if (ret != ACT_P_CREATED)
	dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
	dev_hold(dev);
	rcu_assign_pointer(m->tcfm_dev, dev);
	m->tcfm_ok_push = ok_push;
	}

	if (ret == ACT_P_CREATED) {
	spin_lock_bh(&mirred_list_lock);
	list_add(&m->tcfm_list, &mirred_list);
	spin_unlock_bh(&mirred_list_lock);
	tcf_hash_insert(a);
	}

	return ret;
	}

	static int tcf_mirred(struct sk_buff skb, const struct tc_action a,
	struct tcf_result *res)
	{
	struct tcf_mirred *m = a->priv;
	struct net_device *dev;
	struct sk_buff *skb2;
	int retval, err;
	u32 at;

	tcf_lastuse_update(&m->tcf_tm);

	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);

	rcu_read_lock();
	retval = READ_ONCE(m->tcf_action);
	dev = rcu_dereference(m->tcfm_dev);
	if (unlikely(!dev)) {
	pr_notice_once("tc mirred: target device is gone\n");
	goto out;
	}

	if (unlikely(!(dev->flags & IFF_UP))) {
	net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
	dev->name);
	goto out;
	}

	at = G_TC_AT(skb->tc_verd);
	skb2 = skb_clone(skb, GFP_ATOMIC);
	if (!skb2)
	goto out;

	if (!(at & AT_EGRESS)) {
	if (m->tcfm_ok_push)
	skb_push(skb2, skb->mac_len);
	}

	/* mirror is always swallowed */
	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
	skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);

	skb2->skb_iif = skb->dev->ifindex;
	skb2->dev = dev;
	skb_sender_cpu_clear(skb2);
	err = dev_queue_xmit(skb2);

	if (err) {
	out:
	qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
	retval = TC_ACT_SHOT;
	}
	rcu_read_unlock();

	return retval;
	}

	static int tcf_mirred_dump(struct sk_buff skb, struct tc_action a, int bind, int ref)
	{
	unsigned char *b = skb_tail_pointer(skb);
	struct tcf_mirred *m = a->priv;
	struct tc_mirred opt = {
	.index = m->tcf_index,
	.action = m->tcf_action,
	.refcnt = m->tcf_refcnt - ref,
	.bindcnt = m->tcf_bindcnt - bind,
	.eaction = m->tcfm_eaction,
	.ifindex = m->tcfm_ifindex,
	};
	struct tcf_t t;

	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
	goto nla_put_failure;
	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
	if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
	goto nla_put_failure;
	return skb->len;

	nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
	}

	static int mirred_device_event(struct notifier_block *unused,
	unsigned long event, void *ptr)
	{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct tcf_mirred *m;

	ASSERT_RTNL();
	if (event == NETDEV_UNREGISTER) {
	spin_lock_bh(&mirred_list_lock);
	list_for_each_entry(m, &mirred_list, tcfm_list) {
	if (rcu_access_pointer(m->tcfm_dev) == dev) {
	dev_put(dev);
	/* Note : no rcu grace period necessary, as
	* net_device are already rcu protected.
	*/
	RCU_INIT_POINTER(m->tcfm_dev, NULL);
	}
	}
	spin_unlock_bh(&mirred_list_lock);
	}

	return NOTIFY_DONE;
	}

	static struct notifier_block mirred_device_notifier = {
	.notifier_call = mirred_device_event,
	};

	static struct tc_action_ops act_mirred_ops = {
	.kind = "mirred",
	.type = TCA_ACT_MIRRED,
	.owner = THIS_MODULE,
	.act = tcf_mirred,
	.dump = tcf_mirred_dump,
	.cleanup = tcf_mirred_release,
	.init = tcf_mirred_init,
	};

	MODULE_AUTHOR("Jamal Hadi Salim(2002)");
	MODULE_DESCRIPTION("Device Mirror/redirect actions");
	MODULE_LICENSE("GPL");

	static int __init mirred_init_module(void)
	{
	int err = register_netdevice_notifier(&mirred_device_notifier);
	if (err)
	return err;

	pr_info("Mirror/redirect action on\n");
	return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
	}

	static void __exit mirred_cleanup_module(void)
	{
	tcf_unregister_action(&act_mirred_ops);
	unregister_netdevice_notifier(&mirred_device_notifier);
	}

	module_init(mirred_init_module);
	module_exit(mirred_cleanup_module);