[mirror_ubuntu-focal-kernel.git] / net / sched / act_mirred.c

/*
 * 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 <linux/if_arp.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <linux/tc_act/tc_mirred.h>
#include <net/tc_act/tc_mirred.h>

static LIST_HEAD(mirred_list);
static DEFINE_SPINLOCK(mirred_list_lock);

static bool tcf_mirred_is_act_redirect(int action)
{
	return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
}

static bool tcf_mirred_act_wants_ingress(int action)
{
	switch (action) {
	case TCA_EGRESS_REDIR:
	case TCA_EGRESS_MIRROR:
		return false;
	case TCA_INGRESS_REDIR:
	case TCA_INGRESS_MIRROR:
		return true;
	default:
		BUG();
	}
}

static bool tcf_mirred_can_reinsert(int action)
{
	switch (action) {
	case TC_ACT_SHOT:
	case TC_ACT_STOLEN:
	case TC_ACT_QUEUED:
	case TC_ACT_TRAP:
		return true;
	}
	return false;
}

static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
{
	return rcu_dereference_protected(m->tcfm_dev,
					 lockdep_is_held(&m->tcf_lock));
}

static void tcf_mirred_release(struct tc_action *a)
{
	struct tcf_mirred *m = to_mirred(a);
	struct net_device *dev;

	spin_lock(&mirred_list_lock);
	list_del(&m->tcfm_list);
	spin_unlock(&mirred_list_lock);

	/* last reference to action, no need to lock */
	dev = rcu_dereference_protected(m->tcfm_dev, 1);
	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 unsigned int mirred_net_id;
static struct tc_action_ops act_mirred_ops;

static int tcf_mirred_init(struct net *net, struct nlattr *nla,
			   struct nlattr *est, struct tc_action **a,
			   int ovr, int bind, bool rtnl_held,
			   struct netlink_ext_ack *extack)
{
	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	struct nlattr *tb[TCA_MIRRED_MAX + 1];
	bool mac_header_xmit = false;
	struct tc_mirred *parm;
	struct tcf_mirred *m;
	struct net_device *dev;
	bool exists = false;
	int ret, err;

	if (!nla) {
		NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
		return -EINVAL;
	}
	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy, extack);
	if (ret < 0)
		return ret;
	if (!tb[TCA_MIRRED_PARMS]) {
		NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
		return -EINVAL;
	}
	parm = nla_data(tb[TCA_MIRRED_PARMS]);

	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
	if (err < 0)
		return err;
	exists = err;
	if (exists && bind)
		return 0;

	switch (parm->eaction) {
	case TCA_EGRESS_MIRROR:
	case TCA_EGRESS_REDIR:
	case TCA_INGRESS_REDIR:
	case TCA_INGRESS_MIRROR:
		break;
	default:
		if (exists)
			tcf_idr_release(*a, bind);
		else
			tcf_idr_cleanup(tn, parm->index);
		NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
		return -EINVAL;
	}

	if (!exists) {
		if (!parm->ifindex) {
			tcf_idr_cleanup(tn, parm->index);
			NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
			return -EINVAL;
		}
		ret = tcf_idr_create(tn, parm->index, est, a,
				     &act_mirred_ops, bind, true);
		if (ret) {
			tcf_idr_cleanup(tn, parm->index);
			return ret;
		}
		ret = ACT_P_CREATED;
	} else if (!ovr) {
		tcf_idr_release(*a, bind);
		return -EEXIST;
	}
	m = to_mirred(*a);

	spin_lock_bh(&m->tcf_lock);
	m->tcf_action = parm->action;
	m->tcfm_eaction = parm->eaction;

	if (parm->ifindex) {
		dev = dev_get_by_index(net, parm->ifindex);
		if (!dev) {
			spin_unlock_bh(&m->tcf_lock);
			tcf_idr_release(*a, bind);
			return -ENODEV;
		}
		mac_header_xmit = dev_is_mac_header_xmit(dev);
		rcu_swap_protected(m->tcfm_dev, dev,
				   lockdep_is_held(&m->tcf_lock));
		if (dev)
			dev_put(dev);
		m->tcfm_mac_header_xmit = mac_header_xmit;
	}
	spin_unlock_bh(&m->tcf_lock);

	if (ret == ACT_P_CREATED) {
		spin_lock(&mirred_list_lock);
		list_add(&m->tcfm_list, &mirred_list);
		spin_unlock(&mirred_list_lock);

		tcf_idr_insert(tn, *a);
	}

	return ret;
}

static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
			  struct tcf_result *res)
{
	struct tcf_mirred *m = to_mirred(a);
	struct sk_buff *skb2 = skb;
	bool m_mac_header_xmit;
	struct net_device *dev;
	int retval, err = 0;
	bool use_reinsert;
	bool want_ingress;
	bool is_redirect;
	int m_eaction;
	int mac_len;

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

	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
	m_eaction = READ_ONCE(m->tcfm_eaction);
	retval = READ_ONCE(m->tcf_action);
	dev = rcu_dereference_bh(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;
	}

	/* we could easily avoid the clone only if called by ingress and clsact;
	 * since we can't easily detect the clsact caller, skip clone only for
	 * ingress - that covers the TC S/W datapath.
	 */
	is_redirect = tcf_mirred_is_act_redirect(m_eaction);
	use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
		       tcf_mirred_can_reinsert(retval);
	if (!use_reinsert) {
		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (!skb2)
			goto out;
	}

	/* If action's target direction differs than filter's direction,
	 * and devices expect a mac header on xmit, then mac push/pull is
	 * needed.
	 */
	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
	if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
		if (!skb_at_tc_ingress(skb)) {
			/* caught at egress, act ingress: pull mac */
			mac_len = skb_network_header(skb) - skb_mac_header(skb);
			skb_pull_rcsum(skb2, mac_len);
		} else {
			/* caught at ingress, act egress: push mac */
			skb_push_rcsum(skb2, skb->mac_len);
		}
	}

	skb2->skb_iif = skb->dev->ifindex;
	skb2->dev = dev;

	/* mirror is always swallowed */
	if (is_redirect) {
		skb2->tc_redirected = 1;
		skb2->tc_from_ingress = skb2->tc_at_ingress;

		/* let's the caller reinsert the packet, if possible */
		if (use_reinsert) {
			res->ingress = want_ingress;
			res->qstats = this_cpu_ptr(m->common.cpu_qstats);
			return TC_ACT_REINSERT;
		}
	}

	if (!want_ingress)
		err = dev_queue_xmit(skb2);
	else
		err = netif_receive_skb(skb2);

	if (err) {
out:
		qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
		if (tcf_mirred_is_act_redirect(m_eaction))
			retval = TC_ACT_SHOT;
	}

	return retval;
}

static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
			     u64 lastuse)
{
	struct tcf_mirred *m = to_mirred(a);
	struct tcf_t *tm = &m->tcf_tm;

	_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
}

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 = to_mirred(a);
	struct tc_mirred opt = {
		.index   = m->tcf_index,
		.refcnt  = refcount_read(&m->tcf_refcnt) - ref,
		.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
	};
	struct net_device *dev;
	struct tcf_t t;

	spin_lock_bh(&m->tcf_lock);
	opt.action = m->tcf_action;
	opt.eaction = m->tcfm_eaction;
	dev = tcf_mirred_dev_dereference(m);
	if (dev)
		opt.ifindex = dev->ifindex;

	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
		goto nla_put_failure;

	tcf_tm_dump(&t, &m->tcf_tm);
	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
		goto nla_put_failure;
	spin_unlock_bh(&m->tcf_lock);

	return skb->len;

nla_put_failure:
	spin_unlock_bh(&m->tcf_lock);
	nlmsg_trim(skb, b);
	return -1;
}

static int tcf_mirred_walker(struct net *net, struct sk_buff *skb,
			     struct netlink_callback *cb, int type,
			     const struct tc_action_ops *ops,
			     struct netlink_ext_ack *extack)
{
	struct tc_action_net *tn = net_generic(net, mirred_net_id);

	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
}

static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index,
			     struct netlink_ext_ack *extack)
{
	struct tc_action_net *tn = net_generic(net, mirred_net_id);

	return tcf_idr_search(tn, a, index);
}

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(&mirred_list_lock);
		list_for_each_entry(m, &mirred_list, tcfm_list) {
			spin_lock_bh(&m->tcf_lock);
			if (tcf_mirred_dev_dereference(m) == 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(&m->tcf_lock);
		}
		spin_unlock(&mirred_list_lock);
	}

	return NOTIFY_DONE;
}

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

static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
{
	struct tcf_mirred *m = to_mirred(a);
	struct net_device *dev;

	rcu_read_lock();
	dev = rcu_dereference(m->tcfm_dev);
	if (dev)
		dev_hold(dev);
	rcu_read_unlock();

	return dev;
}

static void tcf_mirred_put_dev(struct net_device *dev)
{
	dev_put(dev);
}

static struct tc_action_ops act_mirred_ops = {
	.kind		=	"mirred",
	.type		=	TCA_ACT_MIRRED,
	.owner		=	THIS_MODULE,
	.act		=	tcf_mirred_act,
	.stats_update	=	tcf_stats_update,
	.dump		=	tcf_mirred_dump,
	.cleanup	=	tcf_mirred_release,
	.init		=	tcf_mirred_init,
	.walk		=	tcf_mirred_walker,
	.lookup		=	tcf_mirred_search,
	.size		=	sizeof(struct tcf_mirred),
	.get_dev	=	tcf_mirred_get_dev,
	.put_dev	=	tcf_mirred_put_dev,
};

static __net_init int mirred_init_net(struct net *net)
{
	struct tc_action_net *tn = net_generic(net, mirred_net_id);

	return tc_action_net_init(tn, &act_mirred_ops);
}

static void __net_exit mirred_exit_net(struct list_head *net_list)
{
	tc_action_net_exit(net_list, mirred_net_id);
}

static struct pernet_operations mirred_net_ops = {
	.init = mirred_init_net,
	.exit_batch = mirred_exit_net,
	.id   = &mirred_net_id,
	.size = sizeof(struct tc_action_net),
};

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_net_ops);
}

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

module_init(mirred_init_module);
module_exit(mirred_cleanup_module);
Commit	Line	Data
1da177e4	1	/*
0c6965dd	2	* net/sched/act_mirred.c packet mirroring and redirect actions
1da177e4 LT	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*
	9	* Authors: Jamal Hadi Salim (2002-4)
	10	*
	11	* TODO: Add ingress support (and socket redirect support)
	12	*
	13	*/
	14
1da177e4 LT	15	#include <linux/types.h>
1da177e4 LT	16	#include <linux/kernel.h>
1da177e4	17	#include <linux/string.h>
1da177e4	18	#include <linux/errno.h>
1da177e4 LT	19	#include <linux/skbuff.h>
	20	#include <linux/rtnetlink.h>
	21	#include <linux/module.h>
	22	#include <linux/init.h>
5a0e3ad6	23	#include <linux/gfp.h>
c491680f	24	#include <linux/if_arp.h>
881d966b	25	#include <net/net_namespace.h>
dc5fc579	26	#include <net/netlink.h>
1da177e4	27	#include <net/pkt_sched.h>
e5cf1baf	28	#include <net/pkt_cls.h>
1da177e4 LT	29	#include <linux/tc_act/tc_mirred.h>
	30	#include <net/tc_act/tc_mirred.h>
	31
3b87956e	32	static LIST_HEAD(mirred_list);
4e232818	33	static DEFINE_SPINLOCK(mirred_list_lock);
1da177e4	34
53592b36 SL	35	static bool tcf_mirred_is_act_redirect(int action)
	36	{
	37	return action == TCA_EGRESS_REDIR \|\| action == TCA_INGRESS_REDIR;
	38	}
	39
8dc07fdb	40	static bool tcf_mirred_act_wants_ingress(int action)
53592b36 SL	41	{
	42	switch (action) {
	43	case TCA_EGRESS_REDIR:
	44	case TCA_EGRESS_MIRROR:
8dc07fdb	45	return false;
53592b36 SL	46	case TCA_INGRESS_REDIR:
53592b36 SL	47	case TCA_INGRESS_MIRROR:
8dc07fdb	48	return true;
53592b36 SL	49	default:
	50	BUG();
	51	}
	52	}
	53
e5cf1baf PA	54	static bool tcf_mirred_can_reinsert(int action)
	55	{
	56	switch (action) {
	57	case TC_ACT_SHOT:
	58	case TC_ACT_STOLEN:
	59	case TC_ACT_QUEUED:
	60	case TC_ACT_TRAP:
	61	return true;
	62	}
	63	return false;
	64	}
	65
4e232818 VB	66	static struct net_device tcf_mirred_dev_dereference(struct tcf_mirred m)
	67	{
	68	return rcu_dereference_protected(m->tcfm_dev,
	69	lockdep_is_held(&m->tcf_lock));
	70	}
	71
9a63b255	72	static void tcf_mirred_release(struct tc_action *a)
1da177e4	73	{
86062033	74	struct tcf_mirred *m = to_mirred(a);
dc327f89	75	struct net_device *dev;
2ee22a90	76
4e232818	77	spin_lock(&mirred_list_lock);
a5b5c958	78	list_del(&m->tcfm_list);
4e232818 VB	79	spin_unlock(&mirred_list_lock);
	80
	81	/* last reference to action, no need to lock */
	82	dev = rcu_dereference_protected(m->tcfm_dev, 1);
2ee22a90 ED	83	if (dev)
2ee22a90 ED	84	dev_put(dev);
1da177e4 LT	85	}
1da177e4 LT	86
53b2bf3f PM	87	static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
	88	[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
	89	};
	90
c7d03a00	91	static unsigned int mirred_net_id;
a85a970a	92	static struct tc_action_ops act_mirred_ops;
ddf97ccd	93
c1b52739	94	static int tcf_mirred_init(struct net net, struct nlattr nla,
789871bb VB	95	struct nlattr est, struct tc_action *a,
	96	int ovr, int bind, bool rtnl_held,
	97	struct netlink_ext_ack *extack)
1da177e4	98	{
ddf97ccd	99	struct tc_action_net *tn = net_generic(net, mirred_net_id);
7ba699c6	100	struct nlattr *tb[TCA_MIRRED_MAX + 1];
16577923	101	bool mac_header_xmit = false;
1da177e4	102	struct tc_mirred *parm;
e9ce1cd3	103	struct tcf_mirred *m;
b76965e0	104	struct net_device *dev;
b2313077	105	bool exists = false;
0190c1d4	106	int ret, err;
1da177e4	107
1d4760c7 AA	108	if (!nla) {
1d4760c7 AA	109	NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
1da177e4	110	return -EINVAL;
1d4760c7 AA	111	}
1d4760c7 AA	112	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy, extack);
b76965e0 CG	113	if (ret < 0)
b76965e0 CG	114	return ret;
1d4760c7 AA	115	if (!tb[TCA_MIRRED_PARMS]) {
1d4760c7 AA	116	NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
1da177e4	117	return -EINVAL;
1d4760c7	118	}
7ba699c6	119	parm = nla_data(tb[TCA_MIRRED_PARMS]);
87dfbdc6	120
0190c1d4 VB	121	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
	122	if (err < 0)
	123	return err;
	124	exists = err;
87dfbdc6 JHS	125	if (exists && bind)
	126	return 0;
	127
b76965e0 CG	128	switch (parm->eaction) {
	129	case TCA_EGRESS_MIRROR:
	130	case TCA_EGRESS_REDIR:
53592b36 SL	131	case TCA_INGRESS_REDIR:
53592b36 SL	132	case TCA_INGRESS_MIRROR:
b76965e0 CG	133	break;
b76965e0 CG	134	default:
87dfbdc6	135	if (exists)
65a206c0	136	tcf_idr_release(*a, bind);
0190c1d4 VB	137	else
0190c1d4 VB	138	tcf_idr_cleanup(tn, parm->index);
1d4760c7	139	NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
b76965e0 CG	140	return -EINVAL;
b76965e0 CG	141	}
1da177e4	142
87dfbdc6	143	if (!exists) {
4e232818	144	if (!parm->ifindex) {
0190c1d4	145	tcf_idr_cleanup(tn, parm->index);
1d4760c7	146	NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
1da177e4	147	return -EINVAL;
1d4760c7	148	}
65a206c0 CM	149	ret = tcf_idr_create(tn, parm->index, est, a,
65a206c0 CM	150	&act_mirred_ops, bind, true);
0190c1d4 VB	151	if (ret) {
0190c1d4 VB	152	tcf_idr_cleanup(tn, parm->index);
86062033	153	return ret;
0190c1d4	154	}
1da177e4	155	ret = ACT_P_CREATED;
4e8ddd7f	156	} else if (!ovr) {
65a206c0	157	tcf_idr_release(*a, bind);
4e8ddd7f	158	return -EEXIST;
1da177e4	159	}
a85a970a	160	m = to_mirred(*a);
1da177e4	161
653cd284	162	spin_lock_bh(&m->tcf_lock);
e9ce1cd3 DM	163	m->tcf_action = parm->action;
e9ce1cd3 DM	164	m->tcfm_eaction = parm->eaction;
4e232818 VB	165
	166	if (parm->ifindex) {
	167	dev = dev_get_by_index(net, parm->ifindex);
	168	if (!dev) {
653cd284	169	spin_unlock_bh(&m->tcf_lock);
4e232818 VB	170	tcf_idr_release(*a, bind);
	171	return -ENODEV;
	172	}
	173	mac_header_xmit = dev_is_mac_header_xmit(dev);
	174	rcu_swap_protected(m->tcfm_dev, dev,
	175	lockdep_is_held(&m->tcf_lock));
	176	if (dev)
	177	dev_put(dev);
16577923	178	m->tcfm_mac_header_xmit = mac_header_xmit;
1da177e4	179	}
653cd284	180	spin_unlock_bh(&m->tcf_lock);
2ee22a90	181
3b87956e	182	if (ret == ACT_P_CREATED) {
4e232818	183	spin_lock(&mirred_list_lock);
3b87956e	184	list_add(&m->tcfm_list, &mirred_list);
4e232818 VB	185	spin_unlock(&mirred_list_lock);
4e232818 VB	186
65a206c0	187	tcf_idr_insert(tn, *a);
3b87956e	188	}
1da177e4	189
1da177e4 LT	190	return ret;
	191	}
	192
7c5790c4 JHS	193	static int tcf_mirred_act(struct sk_buff skb, const struct tc_action a,
7c5790c4 JHS	194	struct tcf_result *res)
1da177e4	195	{
a85a970a	196	struct tcf_mirred *m = to_mirred(a);
e5cf1baf	197	struct sk_buff *skb2 = skb;
53592b36	198	bool m_mac_header_xmit;
1da177e4	199	struct net_device *dev;
53592b36	200	int retval, err = 0;
e5cf1baf PA	201	bool use_reinsert;
	202	bool want_ingress;
	203	bool is_redirect;
53592b36 SL	204	int m_eaction;
53592b36 SL	205	int mac_len;
1da177e4	206
2ee22a90	207	tcf_lastuse_update(&m->tcf_tm);
2ee22a90	208	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
1da177e4	209
53592b36 SL	210	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
53592b36 SL	211	m_eaction = READ_ONCE(m->tcfm_eaction);
2ee22a90	212	retval = READ_ONCE(m->tcf_action);
7fd4b288	213	dev = rcu_dereference_bh(m->tcfm_dev);
2ee22a90 ED	214	if (unlikely(!dev)) {
2ee22a90 ED	215	pr_notice_once("tc mirred: target device is gone\n");
3b87956e	216	goto out;
	217	}
	218
2ee22a90	219	if (unlikely(!(dev->flags & IFF_UP))) {
e87cc472 JP	220	net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
e87cc472 JP	221	dev->name);
feed1f17	222	goto out;
1da177e4 LT	223	}
1da177e4 LT	224
e5cf1baf PA	225	/* we could easily avoid the clone only if called by ingress and clsact;
	226	* since we can't easily detect the clsact caller, skip clone only for
	227	* ingress - that covers the TC S/W datapath.
	228	*/
	229	is_redirect = tcf_mirred_is_act_redirect(m_eaction);
	230	use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
	231	tcf_mirred_can_reinsert(retval);
	232	if (!use_reinsert) {
	233	skb2 = skb_clone(skb, GFP_ATOMIC);
	234	if (!skb2)
	235	goto out;
	236	}
1da177e4	237
53592b36 SL	238	/* If action's target direction differs than filter's direction,
	239	* and devices expect a mac header on xmit, then mac push/pull is
	240	* needed.
	241	*/
e5cf1baf PA	242	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
e5cf1baf PA	243	if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
a5135bcf	244	if (!skb_at_tc_ingress(skb)) {
53592b36 SL	245	/* caught at egress, act ingress: pull mac */
	246	mac_len = skb_network_header(skb) - skb_mac_header(skb);
	247	skb_pull_rcsum(skb2, mac_len);
	248	} else {
	249	/* caught at ingress, act egress: push mac */
82a31b92	250	skb_push_rcsum(skb2, skb->mac_len);
53592b36	251	}
feed1f17	252	}
1da177e4	253
e5cf1baf PA	254	skb2->skb_iif = skb->dev->ifindex;
	255	skb2->dev = dev;
	256
1da177e4	257	/* mirror is always swallowed */
e5cf1baf	258	if (is_redirect) {
bc31c905 WB	259	skb2->tc_redirected = 1;
bc31c905 WB	260	skb2->tc_from_ingress = skb2->tc_at_ingress;
e5cf1baf PA	261
	262	/* let's the caller reinsert the packet, if possible */
	263	if (use_reinsert) {
	264	res->ingress = want_ingress;
	265	res->qstats = this_cpu_ptr(m->common.cpu_qstats);
	266	return TC_ACT_REINSERT;
	267	}
bc31c905	268	}
1da177e4	269
e5cf1baf	270	if (!want_ingress)
53592b36 SL	271	err = dev_queue_xmit(skb2);
	272	else
	273	err = netif_receive_skb(skb2);
feed1f17	274
feed1f17	275	if (err) {
2ee22a90 ED	276	out:
2ee22a90 ED	277	qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
53592b36	278	if (tcf_mirred_is_act_redirect(m_eaction))
16c0b164	279	retval = TC_ACT_SHOT;
2ee22a90	280	}
feed1f17 CG	281
feed1f17 CG	282	return retval;
1da177e4 LT	283	}
1da177e4 LT	284
9798e6fe JK	285	static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
	286	u64 lastuse)
	287	{
5712bf9c PB	288	struct tcf_mirred *m = to_mirred(a);
	289	struct tcf_t *tm = &m->tcf_tm;
	290
9798e6fe	291	_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
3bb23421	292	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
9798e6fe JK	293	}
9798e6fe JK	294
5a7a5555 JHS	295	static int tcf_mirred_dump(struct sk_buff skb, struct tc_action a, int bind,
5a7a5555 JHS	296	int ref)
1da177e4	297	{
27a884dc	298	unsigned char *b = skb_tail_pointer(skb);
a85a970a	299	struct tcf_mirred *m = to_mirred(a);
1c40be12 ED	300	struct tc_mirred opt = {
1c40be12 ED	301	.index = m->tcf_index,
036bb443 VB	302	.refcnt = refcount_read(&m->tcf_refcnt) - ref,
036bb443 VB	303	.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
1c40be12	304	};
4e232818	305	struct net_device *dev;
1da177e4 LT	306	struct tcf_t t;
1da177e4 LT	307
653cd284	308	spin_lock_bh(&m->tcf_lock);
4e232818 VB	309	opt.action = m->tcf_action;
	310	opt.eaction = m->tcfm_eaction;
	311	dev = tcf_mirred_dev_dereference(m);
	312	if (dev)
	313	opt.ifindex = dev->ifindex;
	314
1b34ec43 DM	315	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
1b34ec43 DM	316	goto nla_put_failure;
48d8ee16 JHS	317
48d8ee16 JHS	318	tcf_tm_dump(&t, &m->tcf_tm);
9854518e	319	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
1b34ec43	320	goto nla_put_failure;
653cd284	321	spin_unlock_bh(&m->tcf_lock);
4e232818	322
1da177e4 LT	323	return skb->len;
1da177e4 LT	324
7ba699c6	325	nla_put_failure:
653cd284	326	spin_unlock_bh(&m->tcf_lock);
dc5fc579	327	nlmsg_trim(skb, b);
1da177e4 LT	328	return -1;
	329	}
	330
ddf97ccd WC	331	static int tcf_mirred_walker(struct net net, struct sk_buff skb,
ddf97ccd WC	332	struct netlink_callback *cb, int type,
41780105 AA	333	const struct tc_action_ops *ops,
41780105 AA	334	struct netlink_ext_ack *extack)
ddf97ccd WC	335	{
	336	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	337
b3620145	338	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
ddf97ccd WC	339	}
ddf97ccd WC	340
331a9295 AA	341	static int tcf_mirred_search(struct net net, struct tc_action *a, u32 index,
331a9295 AA	342	struct netlink_ext_ack *extack)
ddf97ccd WC	343	{
	344	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	345
65a206c0	346	return tcf_idr_search(tn, a, index);
ddf97ccd WC	347	}
ddf97ccd WC	348
3b87956e	349	static int mirred_device_event(struct notifier_block *unused,
	350	unsigned long event, void *ptr)
	351	{
351638e7	352	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3b87956e	353	struct tcf_mirred *m;
3b87956e	354
2ee22a90	355	ASSERT_RTNL();
6bd00b85	356	if (event == NETDEV_UNREGISTER) {
4e232818	357	spin_lock(&mirred_list_lock);
3b87956e	358	list_for_each_entry(m, &mirred_list, tcfm_list) {
653cd284	359	spin_lock_bh(&m->tcf_lock);
4e232818	360	if (tcf_mirred_dev_dereference(m) == dev) {
3b87956e	361	dev_put(dev);
2ee22a90 ED	362	/* Note : no rcu grace period necessary, as
	363	* net_device are already rcu protected.
	364	*/
	365	RCU_INIT_POINTER(m->tcfm_dev, NULL);
3b87956e	366	}
653cd284	367	spin_unlock_bh(&m->tcf_lock);
3b87956e	368	}
4e232818	369	spin_unlock(&mirred_list_lock);
6bd00b85	370	}
3b87956e	371
	372	return NOTIFY_DONE;
	373	}
	374
	375	static struct notifier_block mirred_device_notifier = {
	376	.notifier_call = mirred_device_event,
	377	};
	378
843e79d0	379	static struct net_device tcf_mirred_get_dev(const struct tc_action a)
255cb304	380	{
843e79d0	381	struct tcf_mirred *m = to_mirred(a);
4e232818	382	struct net_device *dev;
84a75b32	383
4e232818 VB	384	rcu_read_lock();
4e232818 VB	385	dev = rcu_dereference(m->tcfm_dev);
84a75b32 VB	386	if (dev)
84a75b32 VB	387	dev_hold(dev);
4e232818	388	rcu_read_unlock();
255cb304	389
84a75b32 VB	390	return dev;
	391	}
	392
	393	static void tcf_mirred_put_dev(struct net_device *dev)
	394	{
	395	dev_put(dev);
255cb304 HHZ	396	}
255cb304 HHZ	397
1da177e4 LT	398	static struct tc_action_ops act_mirred_ops = {
	399	.kind = "mirred",
	400	.type = TCA_ACT_MIRRED,
1da177e4	401	.owner = THIS_MODULE,
7c5790c4	402	.act = tcf_mirred_act,
9798e6fe	403	.stats_update = tcf_stats_update,
1da177e4	404	.dump = tcf_mirred_dump,
86062033	405	.cleanup = tcf_mirred_release,
1da177e4	406	.init = tcf_mirred_init,
ddf97ccd WC	407	.walk = tcf_mirred_walker,
ddf97ccd WC	408	.lookup = tcf_mirred_search,
a85a970a	409	.size = sizeof(struct tcf_mirred),
843e79d0	410	.get_dev = tcf_mirred_get_dev,
84a75b32	411	.put_dev = tcf_mirred_put_dev,
ddf97ccd WC	412	};
	413
	414	static __net_init int mirred_init_net(struct net *net)
	415	{
	416	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	417
c7e460ce	418	return tc_action_net_init(tn, &act_mirred_ops);
ddf97ccd WC	419	}
ddf97ccd WC	420
039af9c6	421	static void __net_exit mirred_exit_net(struct list_head *net_list)
ddf97ccd	422	{
039af9c6	423	tc_action_net_exit(net_list, mirred_net_id);
ddf97ccd WC	424	}
	425
	426	static struct pernet_operations mirred_net_ops = {
	427	.init = mirred_init_net,
039af9c6	428	.exit_batch = mirred_exit_net,
ddf97ccd WC	429	.id = &mirred_net_id,
ddf97ccd WC	430	.size = sizeof(struct tc_action_net),
1da177e4 LT	431	};
	432
	433	MODULE_AUTHOR("Jamal Hadi Salim(2002)");
	434	MODULE_DESCRIPTION("Device Mirror/redirect actions");
	435	MODULE_LICENSE("GPL");
	436
e9ce1cd3	437	static int __init mirred_init_module(void)
1da177e4	438	{
3b87956e	439	int err = register_netdevice_notifier(&mirred_device_notifier);
	440	if (err)
	441	return err;
	442
6ff9c364	443	pr_info("Mirror/redirect action on\n");
ddf97ccd	444	return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
1da177e4 LT	445	}
1da177e4 LT	446
e9ce1cd3	447	static void __exit mirred_cleanup_module(void)
1da177e4	448	{
ddf97ccd	449	tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
568a153a	450	unregister_netdevice_notifier(&mirred_device_notifier);
1da177e4 LT	451	}
	452
	453	module_init(mirred_init_module);
	454	module_exit(mirred_cleanup_module);