[linux-2.6-block.git] / net / sched / act_mirred.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/act_mirred.c	packet mirroring and redirect actions
 *
 * 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);

#define MIRRED_RECURSION_LIMIT    4
static DEFINE_PER_CPU(unsigned int, mirred_rec_level);

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 tcf_proto *tp,
			   struct netlink_ext_ack *extack)
{
	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	struct nlattr *tb[TCA_MIRRED_MAX + 1];
	struct tcf_chain *goto_ch = NULL;
	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_deprecated(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);
	if (ret == ACT_P_CREATED)
		INIT_LIST_HEAD(&m->tcfm_list);

	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
	if (err < 0)
		goto release_idr;

	spin_lock_bh(&m->tcf_lock);

	if (parm->ifindex) {
		dev = dev_get_by_index(net, parm->ifindex);
		if (!dev) {
			spin_unlock_bh(&m->tcf_lock);
			err = -ENODEV;
			goto put_chain;
		}
		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;
	}
	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
	m->tcfm_eaction = parm->eaction;
	spin_unlock_bh(&m->tcf_lock);
	if (goto_ch)
		tcf_chain_put_by_act(goto_ch);

	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;
put_chain:
	if (goto_ch)
		tcf_chain_put_by_act(goto_ch);
release_idr:
	tcf_idr_release(*a, bind);
	return err;
}

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;
	unsigned int rec_level;
	int retval, err = 0;
	bool use_reinsert;
	bool want_ingress;
	bool is_redirect;
	int m_eaction;
	int mac_len;

	rec_level = __this_cpu_inc_return(mirred_rec_level);
	if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
		net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
				     netdev_name(skb->dev));
		__this_cpu_dec(mirred_rec_level);
		return TC_ACT_SHOT;
	}

	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;
		if (skb2->tc_from_ingress)
			skb2->tstamp = 0;
		/* 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);
			skb_tc_reinsert(skb, res);
			__this_cpu_dec(mirred_rec_level);
			return TC_ACT_CONSUMED;
		}
	}

	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;
	}
	__this_cpu_dec(mirred_rec_level);

	return retval;
}

static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
			     u64 lastuse, bool hw)
{
	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);
	if (hw)
		_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats_hw),
				   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 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 size_t tcf_mirred_get_fill_size(const struct tc_action *act)
{
	return nla_total_size(sizeof(struct tc_mirred));
}

static struct tc_action_ops act_mirred_ops = {
	.kind		=	"mirred",
	.id		=	TCA_ID_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,
	.get_fill_size	=	tcf_mirred_get_fill_size,
	.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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
0c6965dd	3	* net/sched/act_mirred.c packet mirroring and redirect actions
1da177e4	4	*
1da177e4 LT	5	* Authors: Jamal Hadi Salim (2002-4)
	6	*
	7	* TODO: Add ingress support (and socket redirect support)
1da177e4 LT	8	*/
1da177e4 LT	9
1da177e4 LT	10	#include <linux/types.h>
1da177e4 LT	11	#include <linux/kernel.h>
1da177e4	12	#include <linux/string.h>
1da177e4	13	#include <linux/errno.h>
1da177e4 LT	14	#include <linux/skbuff.h>
	15	#include <linux/rtnetlink.h>
	16	#include <linux/module.h>
	17	#include <linux/init.h>
5a0e3ad6	18	#include <linux/gfp.h>
c491680f	19	#include <linux/if_arp.h>
881d966b	20	#include <net/net_namespace.h>
dc5fc579	21	#include <net/netlink.h>
1da177e4	22	#include <net/pkt_sched.h>
e5cf1baf	23	#include <net/pkt_cls.h>
1da177e4 LT	24	#include <linux/tc_act/tc_mirred.h>
	25	#include <net/tc_act/tc_mirred.h>
	26
3b87956e	27	static LIST_HEAD(mirred_list);
4e232818	28	static DEFINE_SPINLOCK(mirred_list_lock);
1da177e4	29
e2ca070f JH	30	#define MIRRED_RECURSION_LIMIT 4
	31	static DEFINE_PER_CPU(unsigned int, mirred_rec_level);
	32
53592b36 SL	33	static bool tcf_mirred_is_act_redirect(int action)
	34	{
	35	return action == TCA_EGRESS_REDIR \|\| action == TCA_INGRESS_REDIR;
	36	}
	37
8dc07fdb	38	static bool tcf_mirred_act_wants_ingress(int action)
53592b36 SL	39	{
	40	switch (action) {
	41	case TCA_EGRESS_REDIR:
	42	case TCA_EGRESS_MIRROR:
8dc07fdb	43	return false;
53592b36 SL	44	case TCA_INGRESS_REDIR:
53592b36 SL	45	case TCA_INGRESS_MIRROR:
8dc07fdb	46	return true;
53592b36 SL	47	default:
	48	BUG();
	49	}
	50	}
	51
e5cf1baf PA	52	static bool tcf_mirred_can_reinsert(int action)
	53	{
	54	switch (action) {
	55	case TC_ACT_SHOT:
	56	case TC_ACT_STOLEN:
	57	case TC_ACT_QUEUED:
	58	case TC_ACT_TRAP:
	59	return true;
	60	}
	61	return false;
	62	}
	63
4e232818 VB	64	static struct net_device tcf_mirred_dev_dereference(struct tcf_mirred m)
	65	{
	66	return rcu_dereference_protected(m->tcfm_dev,
	67	lockdep_is_held(&m->tcf_lock));
	68	}
	69
9a63b255	70	static void tcf_mirred_release(struct tc_action *a)
1da177e4	71	{
86062033	72	struct tcf_mirred *m = to_mirred(a);
dc327f89	73	struct net_device *dev;
2ee22a90	74
4e232818	75	spin_lock(&mirred_list_lock);
a5b5c958	76	list_del(&m->tcfm_list);
4e232818 VB	77	spin_unlock(&mirred_list_lock);
	78
	79	/* last reference to action, no need to lock */
	80	dev = rcu_dereference_protected(m->tcfm_dev, 1);
2ee22a90 ED	81	if (dev)
2ee22a90 ED	82	dev_put(dev);
1da177e4 LT	83	}
1da177e4 LT	84
53b2bf3f PM	85	static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
	86	[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
	87	};
	88
c7d03a00	89	static unsigned int mirred_net_id;
a85a970a	90	static struct tc_action_ops act_mirred_ops;
ddf97ccd	91
c1b52739	92	static int tcf_mirred_init(struct net net, struct nlattr nla,
789871bb VB	93	struct nlattr est, struct tc_action *a,
789871bb VB	94	int ovr, int bind, bool rtnl_held,
85d0966f	95	struct tcf_proto *tp,
789871bb	96	struct netlink_ext_ack *extack)
1da177e4	97	{
ddf97ccd	98	struct tc_action_net *tn = net_generic(net, mirred_net_id);
7ba699c6	99	struct nlattr *tb[TCA_MIRRED_MAX + 1];
ff9721d3	100	struct tcf_chain *goto_ch = NULL;
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	111	}
8cb08174 JB	112	ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
8cb08174 JB	113	mirred_policy, extack);
b76965e0 CG	114	if (ret < 0)
b76965e0 CG	115	return ret;
1d4760c7 AA	116	if (!tb[TCA_MIRRED_PARMS]) {
1d4760c7 AA	117	NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
1da177e4	118	return -EINVAL;
1d4760c7	119	}
7ba699c6	120	parm = nla_data(tb[TCA_MIRRED_PARMS]);
87dfbdc6	121
0190c1d4 VB	122	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
	123	if (err < 0)
	124	return err;
	125	exists = err;
87dfbdc6 JHS	126	if (exists && bind)
	127	return 0;
	128
b76965e0 CG	129	switch (parm->eaction) {
	130	case TCA_EGRESS_MIRROR:
	131	case TCA_EGRESS_REDIR:
53592b36 SL	132	case TCA_INGRESS_REDIR:
53592b36 SL	133	case TCA_INGRESS_MIRROR:
b76965e0 CG	134	break;
b76965e0 CG	135	default:
87dfbdc6	136	if (exists)
65a206c0	137	tcf_idr_release(*a, bind);
0190c1d4 VB	138	else
0190c1d4 VB	139	tcf_idr_cleanup(tn, parm->index);
1d4760c7	140	NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
b76965e0 CG	141	return -EINVAL;
b76965e0 CG	142	}
1da177e4	143
87dfbdc6	144	if (!exists) {
4e232818	145	if (!parm->ifindex) {
0190c1d4	146	tcf_idr_cleanup(tn, parm->index);
1d4760c7	147	NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
1da177e4	148	return -EINVAL;
1d4760c7	149	}
65a206c0 CM	150	ret = tcf_idr_create(tn, parm->index, est, a,
65a206c0 CM	151	&act_mirred_ops, bind, true);
0190c1d4 VB	152	if (ret) {
0190c1d4 VB	153	tcf_idr_cleanup(tn, parm->index);
86062033	154	return ret;
0190c1d4	155	}
1da177e4	156	ret = ACT_P_CREATED;
4e8ddd7f	157	} else if (!ovr) {
65a206c0	158	tcf_idr_release(*a, bind);
4e8ddd7f	159	return -EEXIST;
1da177e4	160	}
064c5d68 JH	161
	162	m = to_mirred(*a);
	163	if (ret == ACT_P_CREATED)
	164	INIT_LIST_HEAD(&m->tcfm_list);
	165
ff9721d3 DC	166	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
	167	if (err < 0)
	168	goto release_idr;
	169
653cd284	170	spin_lock_bh(&m->tcf_lock);
4e232818 VB	171
	172	if (parm->ifindex) {
	173	dev = dev_get_by_index(net, parm->ifindex);
	174	if (!dev) {
653cd284	175	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	176	err = -ENODEV;
ff9721d3 DC	177	goto put_chain;
4e232818 VB	178	}
	179	mac_header_xmit = dev_is_mac_header_xmit(dev);
	180	rcu_swap_protected(m->tcfm_dev, dev,
	181	lockdep_is_held(&m->tcf_lock));
	182	if (dev)
	183	dev_put(dev);
16577923	184	m->tcfm_mac_header_xmit = mac_header_xmit;
1da177e4	185	}
ff9721d3 DC	186	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
ff9721d3 DC	187	m->tcfm_eaction = parm->eaction;
653cd284	188	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	189	if (goto_ch)
ff9721d3 DC	190	tcf_chain_put_by_act(goto_ch);
2ee22a90	191
3b87956e	192	if (ret == ACT_P_CREATED) {
4e232818	193	spin_lock(&mirred_list_lock);
3b87956e	194	list_add(&m->tcfm_list, &mirred_list);
4e232818 VB	195	spin_unlock(&mirred_list_lock);
4e232818 VB	196
65a206c0	197	tcf_idr_insert(tn, *a);
3b87956e	198	}
1da177e4	199
1da177e4	200	return ret;
ff9721d3 DC	201	put_chain:
	202	if (goto_ch)
	203	tcf_chain_put_by_act(goto_ch);
	204	release_idr:
	205	tcf_idr_release(*a, bind);
	206	return err;
1da177e4 LT	207	}
1da177e4 LT	208
7c5790c4 JHS	209	static int tcf_mirred_act(struct sk_buff skb, const struct tc_action a,
7c5790c4 JHS	210	struct tcf_result *res)
1da177e4	211	{
a85a970a	212	struct tcf_mirred *m = to_mirred(a);
e5cf1baf	213	struct sk_buff *skb2 = skb;
53592b36	214	bool m_mac_header_xmit;
1da177e4	215	struct net_device *dev;
e2ca070f	216	unsigned int rec_level;
53592b36	217	int retval, err = 0;
e5cf1baf PA	218	bool use_reinsert;
	219	bool want_ingress;
	220	bool is_redirect;
53592b36 SL	221	int m_eaction;
53592b36 SL	222	int mac_len;
1da177e4	223
e2ca070f JH	224	rec_level = __this_cpu_inc_return(mirred_rec_level);
	225	if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
	226	net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
	227	netdev_name(skb->dev));
	228	__this_cpu_dec(mirred_rec_level);
	229	return TC_ACT_SHOT;
	230	}
	231
2ee22a90	232	tcf_lastuse_update(&m->tcf_tm);
2ee22a90	233	bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
1da177e4	234
53592b36 SL	235	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
53592b36 SL	236	m_eaction = READ_ONCE(m->tcfm_eaction);
2ee22a90	237	retval = READ_ONCE(m->tcf_action);
7fd4b288	238	dev = rcu_dereference_bh(m->tcfm_dev);
2ee22a90 ED	239	if (unlikely(!dev)) {
2ee22a90 ED	240	pr_notice_once("tc mirred: target device is gone\n");
3b87956e	241	goto out;
	242	}
	243
2ee22a90	244	if (unlikely(!(dev->flags & IFF_UP))) {
e87cc472 JP	245	net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
e87cc472 JP	246	dev->name);
feed1f17	247	goto out;
1da177e4 LT	248	}
1da177e4 LT	249
e5cf1baf PA	250	/* we could easily avoid the clone only if called by ingress and clsact;
	251	* since we can't easily detect the clsact caller, skip clone only for
	252	* ingress - that covers the TC S/W datapath.
	253	*/
	254	is_redirect = tcf_mirred_is_act_redirect(m_eaction);
	255	use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
	256	tcf_mirred_can_reinsert(retval);
	257	if (!use_reinsert) {
	258	skb2 = skb_clone(skb, GFP_ATOMIC);
	259	if (!skb2)
	260	goto out;
	261	}
1da177e4	262
53592b36 SL	263	/* If action's target direction differs than filter's direction,
	264	* and devices expect a mac header on xmit, then mac push/pull is
	265	* needed.
	266	*/
e5cf1baf PA	267	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
e5cf1baf PA	268	if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
a5135bcf	269	if (!skb_at_tc_ingress(skb)) {
53592b36 SL	270	/* caught at egress, act ingress: pull mac */
	271	mac_len = skb_network_header(skb) - skb_mac_header(skb);
	272	skb_pull_rcsum(skb2, mac_len);
	273	} else {
	274	/* caught at ingress, act egress: push mac */
82a31b92	275	skb_push_rcsum(skb2, skb->mac_len);
53592b36	276	}
feed1f17	277	}
1da177e4	278
e5cf1baf PA	279	skb2->skb_iif = skb->dev->ifindex;
	280	skb2->dev = dev;
	281
1da177e4	282	/* mirror is always swallowed */
e5cf1baf	283	if (is_redirect) {
bc31c905 WB	284	skb2->tc_redirected = 1;
bc31c905 WB	285	skb2->tc_from_ingress = skb2->tc_at_ingress;
7236ead1 ED	286	if (skb2->tc_from_ingress)
7236ead1 ED	287	skb2->tstamp = 0;
e5cf1baf PA	288	/* let's the caller reinsert the packet, if possible */
	289	if (use_reinsert) {
	290	res->ingress = want_ingress;
	291	res->qstats = this_cpu_ptr(m->common.cpu_qstats);
720f22fe	292	skb_tc_reinsert(skb, res);
e2ca070f	293	__this_cpu_dec(mirred_rec_level);
720f22fe	294	return TC_ACT_CONSUMED;
e5cf1baf	295	}
bc31c905	296	}
1da177e4	297
e5cf1baf	298	if (!want_ingress)
53592b36 SL	299	err = dev_queue_xmit(skb2);
	300	else
	301	err = netif_receive_skb(skb2);
feed1f17	302
feed1f17	303	if (err) {
2ee22a90 ED	304	out:
2ee22a90 ED	305	qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
53592b36	306	if (tcf_mirred_is_act_redirect(m_eaction))
16c0b164	307	retval = TC_ACT_SHOT;
2ee22a90	308	}
e2ca070f	309	__this_cpu_dec(mirred_rec_level);
feed1f17 CG	310
feed1f17 CG	311	return retval;
1da177e4 LT	312	}
1da177e4 LT	313
9798e6fe	314	static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
28169aba	315	u64 lastuse, bool hw)
9798e6fe	316	{
5712bf9c PB	317	struct tcf_mirred *m = to_mirred(a);
	318	struct tcf_t *tm = &m->tcf_tm;
	319
9798e6fe	320	_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
28169aba EC	321	if (hw)
	322	_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats_hw),
	323	bytes, packets);
3bb23421	324	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
9798e6fe JK	325	}
9798e6fe JK	326
5a7a5555 JHS	327	static int tcf_mirred_dump(struct sk_buff skb, struct tc_action a, int bind,
5a7a5555 JHS	328	int ref)
1da177e4	329	{
27a884dc	330	unsigned char *b = skb_tail_pointer(skb);
a85a970a	331	struct tcf_mirred *m = to_mirred(a);
1c40be12 ED	332	struct tc_mirred opt = {
1c40be12 ED	333	.index = m->tcf_index,
036bb443 VB	334	.refcnt = refcount_read(&m->tcf_refcnt) - ref,
036bb443 VB	335	.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
1c40be12	336	};
4e232818	337	struct net_device *dev;
1da177e4 LT	338	struct tcf_t t;
1da177e4 LT	339
653cd284	340	spin_lock_bh(&m->tcf_lock);
4e232818 VB	341	opt.action = m->tcf_action;
	342	opt.eaction = m->tcfm_eaction;
	343	dev = tcf_mirred_dev_dereference(m);
	344	if (dev)
	345	opt.ifindex = dev->ifindex;
	346
1b34ec43 DM	347	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
1b34ec43 DM	348	goto nla_put_failure;
48d8ee16 JHS	349
48d8ee16 JHS	350	tcf_tm_dump(&t, &m->tcf_tm);
9854518e	351	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
1b34ec43	352	goto nla_put_failure;
653cd284	353	spin_unlock_bh(&m->tcf_lock);
4e232818	354
1da177e4 LT	355	return skb->len;
1da177e4 LT	356
7ba699c6	357	nla_put_failure:
653cd284	358	spin_unlock_bh(&m->tcf_lock);
dc5fc579	359	nlmsg_trim(skb, b);
1da177e4 LT	360	return -1;
	361	}
	362
ddf97ccd WC	363	static int tcf_mirred_walker(struct net net, struct sk_buff skb,
ddf97ccd WC	364	struct netlink_callback *cb, int type,
41780105 AA	365	const struct tc_action_ops *ops,
41780105 AA	366	struct netlink_ext_ack *extack)
ddf97ccd WC	367	{
	368	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	369
b3620145	370	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
ddf97ccd WC	371	}
ddf97ccd WC	372
f061b48c	373	static int tcf_mirred_search(struct net net, struct tc_action *a, u32 index)
ddf97ccd WC	374	{
	375	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	376
65a206c0	377	return tcf_idr_search(tn, a, index);
ddf97ccd WC	378	}
ddf97ccd WC	379
3b87956e	380	static int mirred_device_event(struct notifier_block *unused,
	381	unsigned long event, void *ptr)
	382	{
351638e7	383	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3b87956e	384	struct tcf_mirred *m;
3b87956e	385
2ee22a90	386	ASSERT_RTNL();
6bd00b85	387	if (event == NETDEV_UNREGISTER) {
4e232818	388	spin_lock(&mirred_list_lock);
3b87956e	389	list_for_each_entry(m, &mirred_list, tcfm_list) {
653cd284	390	spin_lock_bh(&m->tcf_lock);
4e232818	391	if (tcf_mirred_dev_dereference(m) == dev) {
3b87956e	392	dev_put(dev);
2ee22a90 ED	393	/* Note : no rcu grace period necessary, as
	394	* net_device are already rcu protected.
	395	*/
	396	RCU_INIT_POINTER(m->tcfm_dev, NULL);
3b87956e	397	}
653cd284	398	spin_unlock_bh(&m->tcf_lock);
3b87956e	399	}
4e232818	400	spin_unlock(&mirred_list_lock);
6bd00b85	401	}
3b87956e	402
	403	return NOTIFY_DONE;
	404	}
	405
	406	static struct notifier_block mirred_device_notifier = {
	407	.notifier_call = mirred_device_event,
	408	};
	409
843e79d0	410	static struct net_device tcf_mirred_get_dev(const struct tc_action a)
255cb304	411	{
843e79d0	412	struct tcf_mirred *m = to_mirred(a);
4e232818	413	struct net_device *dev;
84a75b32	414
4e232818 VB	415	rcu_read_lock();
4e232818 VB	416	dev = rcu_dereference(m->tcfm_dev);
84a75b32 VB	417	if (dev)
84a75b32 VB	418	dev_hold(dev);
4e232818	419	rcu_read_unlock();
255cb304	420
84a75b32 VB	421	return dev;
	422	}
	423
	424	static void tcf_mirred_put_dev(struct net_device *dev)
	425	{
	426	dev_put(dev);
255cb304 HHZ	427	}
255cb304 HHZ	428
b84b2d4e RM	429	static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
	430	{
	431	return nla_total_size(sizeof(struct tc_mirred));
	432	}
	433
1da177e4 LT	434	static struct tc_action_ops act_mirred_ops = {
1da177e4 LT	435	.kind = "mirred",
eddd2cf1	436	.id = TCA_ID_MIRRED,
1da177e4	437	.owner = THIS_MODULE,
7c5790c4	438	.act = tcf_mirred_act,
9798e6fe	439	.stats_update = tcf_stats_update,
1da177e4	440	.dump = tcf_mirred_dump,
86062033	441	.cleanup = tcf_mirred_release,
1da177e4	442	.init = tcf_mirred_init,
ddf97ccd WC	443	.walk = tcf_mirred_walker,
ddf97ccd WC	444	.lookup = tcf_mirred_search,
b84b2d4e	445	.get_fill_size = tcf_mirred_get_fill_size,
a85a970a	446	.size = sizeof(struct tcf_mirred),
843e79d0	447	.get_dev = tcf_mirred_get_dev,
84a75b32	448	.put_dev = tcf_mirred_put_dev,
ddf97ccd WC	449	};
	450
	451	static __net_init int mirred_init_net(struct net *net)
	452	{
	453	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	454
c7e460ce	455	return tc_action_net_init(tn, &act_mirred_ops);
ddf97ccd WC	456	}
ddf97ccd WC	457
039af9c6	458	static void __net_exit mirred_exit_net(struct list_head *net_list)
ddf97ccd	459	{
039af9c6	460	tc_action_net_exit(net_list, mirred_net_id);
ddf97ccd WC	461	}
	462
	463	static struct pernet_operations mirred_net_ops = {
	464	.init = mirred_init_net,
039af9c6	465	.exit_batch = mirred_exit_net,
ddf97ccd WC	466	.id = &mirred_net_id,
ddf97ccd WC	467	.size = sizeof(struct tc_action_net),
1da177e4 LT	468	};
	469
	470	MODULE_AUTHOR("Jamal Hadi Salim(2002)");
	471	MODULE_DESCRIPTION("Device Mirror/redirect actions");
	472	MODULE_LICENSE("GPL");
	473
e9ce1cd3	474	static int __init mirred_init_module(void)
1da177e4	475	{
3b87956e	476	int err = register_netdevice_notifier(&mirred_device_notifier);
	477	if (err)
	478	return err;
	479
6ff9c364	480	pr_info("Mirror/redirect action on\n");
ddf97ccd	481	return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
1da177e4 LT	482	}
1da177e4 LT	483
e9ce1cd3	484	static void __exit mirred_cleanup_module(void)
1da177e4	485	{
ddf97ccd	486	tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
568a153a	487	unregister_netdevice_notifier(&mirred_device_notifier);
1da177e4 LT	488	}
	489
	490	module_init(mirred_init_module);
	491	module_exit(mirred_cleanup_module);