[linux-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/dst.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>
#include <net/tc_wrapper.h>

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

#define MIRRED_NEST_LIMIT    4
static DEFINE_PER_CPU(unsigned int, mirred_nest_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);
	netdev_put(dev, &m->tcfm_dev_tracker);
}

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

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,
			   struct tcf_proto *tp,
			   u32 flags, struct netlink_ext_ack *extack)
{
	struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
	bool bind = flags & TCA_ACT_FLAGS_BIND;
	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;
	bool exists = false;
	int ret, err;
	u32 index;

	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]);
	index = parm->index;
	err = tcf_idr_check_alloc(tn, &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, index);
		NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
		return -EINVAL;
	}

	if (!exists) {
		if (!parm->ifindex) {
			tcf_idr_cleanup(tn, index);
			NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
			return -EINVAL;
		}
		ret = tcf_idr_create_from_flags(tn, index, est, a,
						&act_mirred_ops, bind, flags);
		if (ret) {
			tcf_idr_cleanup(tn, index);
			return ret;
		}
		ret = ACT_P_CREATED;
	} else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
		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) {
		struct net_device *odev, *ndev;

		ndev = dev_get_by_index(net, parm->ifindex);
		if (!ndev) {
			spin_unlock_bh(&m->tcf_lock);
			err = -ENODEV;
			goto put_chain;
		}
		mac_header_xmit = dev_is_mac_header_xmit(ndev);
		odev = rcu_replace_pointer(m->tcfm_dev, ndev,
					  lockdep_is_held(&m->tcf_lock));
		netdev_put(odev, &m->tcfm_dev_tracker);
		netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
		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);
	}

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

static bool is_mirred_nested(void)
{
	return unlikely(__this_cpu_read(mirred_nest_level) > 1);
}

static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
{
	int err;

	if (!want_ingress)
		err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
	else if (is_mirred_nested())
		err = netif_rx(skb);
	else
		err = netif_receive_skb(skb);

	return err;
}

TC_INDIRECT_SCOPE 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 nest_level;
	int retval, err = 0;
	bool use_reinsert;
	bool want_ingress;
	bool is_redirect;
	bool expects_nh;
	bool at_ingress;
	int m_eaction;
	int mac_len;
	bool at_nh;

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

	tcf_lastuse_update(&m->tcf_tm);
	tcf_action_update_bstats(&m->common, 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)) || !netif_carrier_ok(dev)) {
		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);
	at_ingress = skb_at_tc_ingress(skb);
	use_reinsert = at_ingress && is_redirect &&
		       tcf_mirred_can_reinsert(retval);
	if (!use_reinsert) {
		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (!skb2)
			goto out;
	}

	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);

	/* All mirred/redirected skbs should clear previous ct info */
	nf_reset_ct(skb2);
	if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
		skb_dst_drop(skb2);

	expects_nh = want_ingress || !m_mac_header_xmit;
	at_nh = skb->data == skb_network_header(skb);
	if (at_nh != expects_nh) {
		mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
			  skb_network_offset(skb);
		if (expects_nh) {
			/* target device/action expect data at nh */
			skb_pull_rcsum(skb2, mac_len);
		} else {
			/* target device/action expect data at mac */
			skb_push_rcsum(skb2, mac_len);
		}
	}

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

	/* mirror is always swallowed */
	if (is_redirect) {
		skb_set_redirected(skb2, skb2->tc_at_ingress);

		/* let's the caller reinsert the packet, if possible */
		if (use_reinsert) {
			err = tcf_mirred_forward(want_ingress, skb);
			if (err)
				tcf_action_inc_overlimit_qstats(&m->common);
			__this_cpu_dec(mirred_nest_level);
			return TC_ACT_CONSUMED;
		}
	}

	err = tcf_mirred_forward(want_ingress, skb2);
	if (err) {
out:
		tcf_action_inc_overlimit_qstats(&m->common);
		if (tcf_mirred_is_act_redirect(m_eaction))
			retval = TC_ACT_SHOT;
	}
	__this_cpu_dec(mirred_nest_level);

	return retval;
}

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

	tcf_action_update_stats(a, bytes, packets, drops, hw);
	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 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) {
				netdev_put(dev, &m->tcfm_dev_tracker);
				/* 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 void tcf_mirred_dev_put(void *priv)
{
	struct net_device *dev = priv;

	dev_put(dev);
}

static struct net_device *
tcf_mirred_get_dev(const struct tc_action *a,
		   tc_action_priv_destructor *destructor)
{
	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);
		*destructor = tcf_mirred_dev_put;
	}
	rcu_read_unlock();

	return dev;
}

static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
{
	return nla_total_size(sizeof(struct tc_mirred));
}

static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
				       const struct tc_action *act)
{
	entry->dev = act->ops->get_dev(act, &entry->destructor);
	if (!entry->dev)
		return;
	entry->destructor_priv = entry->dev;
}

static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data,
					u32 *index_inc, bool bind,
					struct netlink_ext_ack *extack)
{
	if (bind) {
		struct flow_action_entry *entry = entry_data;

		if (is_tcf_mirred_egress_redirect(act)) {
			entry->id = FLOW_ACTION_REDIRECT;
			tcf_offload_mirred_get_dev(entry, act);
		} else if (is_tcf_mirred_egress_mirror(act)) {
			entry->id = FLOW_ACTION_MIRRED;
			tcf_offload_mirred_get_dev(entry, act);
		} else if (is_tcf_mirred_ingress_redirect(act)) {
			entry->id = FLOW_ACTION_REDIRECT_INGRESS;
			tcf_offload_mirred_get_dev(entry, act);
		} else if (is_tcf_mirred_ingress_mirror(act)) {
			entry->id = FLOW_ACTION_MIRRED_INGRESS;
			tcf_offload_mirred_get_dev(entry, act);
		} else {
			NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
			return -EOPNOTSUPP;
		}
		*index_inc = 1;
	} else {
		struct flow_offload_action *fl_action = entry_data;

		if (is_tcf_mirred_egress_redirect(act))
			fl_action->id = FLOW_ACTION_REDIRECT;
		else if (is_tcf_mirred_egress_mirror(act))
			fl_action->id = FLOW_ACTION_MIRRED;
		else if (is_tcf_mirred_ingress_redirect(act))
			fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
		else if (is_tcf_mirred_ingress_mirror(act))
			fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
		else
			return -EOPNOTSUPP;
	}

	return 0;
}

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,
	.get_fill_size	=	tcf_mirred_get_fill_size,
	.offload_act_setup =	tcf_mirred_offload_act_setup,
	.size		=	sizeof(struct tcf_mirred),
	.get_dev	=	tcf_mirred_get_dev,
};

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

	return tc_action_net_init(net, tn, &act_mirred_ops);
}

static void __net_exit mirred_exit_net(struct list_head *net_list)
{
	tc_action_net_exit(net_list, act_mirred_ops.net_id);
}

static struct pernet_operations mirred_net_ops = {
	.init = mirred_init_net,
	.exit_batch = mirred_exit_net,
	.id   = &act_mirred_ops.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");
	err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
	if (err)
		unregister_netdevice_notifier(&mirred_device_notifier);

	return err;
}

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>
f799ada6	22	#include <net/dst.h>
1da177e4	23	#include <net/pkt_sched.h>
e5cf1baf	24	#include <net/pkt_cls.h>
1da177e4 LT	25	#include <linux/tc_act/tc_mirred.h>
1da177e4 LT	26	#include <net/tc_act/tc_mirred.h>
871cf386	27	#include <net/tc_wrapper.h>
1da177e4	28
3b87956e	29	static LIST_HEAD(mirred_list);
4e232818	30	static DEFINE_SPINLOCK(mirred_list_lock);
1da177e4	31
78dcdffe DC	32	#define MIRRED_NEST_LIMIT 4
78dcdffe DC	33	static DEFINE_PER_CPU(unsigned int, mirred_nest_level);
e2ca070f	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);
d62607c3	83	netdev_put(dev, &m->tcfm_dev_tracker);
1da177e4 LT	84	}
1da177e4 LT	85
53b2bf3f PM	86	static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
	87	[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
	88	};
	89
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	93	struct nlattr est, struct tc_action *a,
85d0966f	94	struct tcf_proto *tp,
abbb0d33	95	u32 flags, struct netlink_ext_ack *extack)
1da177e4	96	{
acd0a7ab	97	struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
695176bf	98	bool bind = flags & TCA_ACT_FLAGS_BIND;
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;
b2313077	104	bool exists = false;
0190c1d4	105	int ret, err;
7be8ef2c	106	u32 index;
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]);
7be8ef2c DL	121	index = parm->index;
7be8ef2c DL	122	err = tcf_idr_check_alloc(tn, &index, a, bind);
0190c1d4 VB	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	138	else
7be8ef2c	139	tcf_idr_cleanup(tn, 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) {
7be8ef2c	146	tcf_idr_cleanup(tn, index);
1d4760c7	147	NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
1da177e4	148	return -EINVAL;
1d4760c7	149	}
e3822678 VB	150	ret = tcf_idr_create_from_flags(tn, index, est, a,
e3822678 VB	151	&act_mirred_ops, bind, flags);
0190c1d4	152	if (ret) {
7be8ef2c	153	tcf_idr_cleanup(tn, index);
86062033	154	return ret;
0190c1d4	155	}
1da177e4	156	ret = ACT_P_CREATED;
695176bf	157	} else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
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
4e232818 VB	172	if (parm->ifindex) {
ada066b2 ED	173	struct net_device odev, ndev;
	174
	175	ndev = dev_get_by_index(net, parm->ifindex);
	176	if (!ndev) {
653cd284	177	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	178	err = -ENODEV;
ff9721d3 DC	179	goto put_chain;
4e232818	180	}
ada066b2 ED	181	mac_header_xmit = dev_is_mac_header_xmit(ndev);
ada066b2 ED	182	odev = rcu_replace_pointer(m->tcfm_dev, ndev,
445d3749	183	lockdep_is_held(&m->tcf_lock));
d62607c3	184	netdev_put(odev, &m->tcfm_dev_tracker);
ada066b2	185	netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC);
16577923	186	m->tcfm_mac_header_xmit = mac_header_xmit;
1da177e4	187	}
ff9721d3 DC	188	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
ff9721d3 DC	189	m->tcfm_eaction = parm->eaction;
653cd284	190	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	191	if (goto_ch)
ff9721d3 DC	192	tcf_chain_put_by_act(goto_ch);
2ee22a90	193
3b87956e	194	if (ret == ACT_P_CREATED) {
4e232818	195	spin_lock(&mirred_list_lock);
3b87956e	196	list_add(&m->tcfm_list, &mirred_list);
4e232818	197	spin_unlock(&mirred_list_lock);
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
ca22da2f DC	209	static bool is_mirred_nested(void)
	210	{
	211	return unlikely(__this_cpu_read(mirred_nest_level) > 1);
	212	}
	213
fa6d6399	214	static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
	215	{
	216	int err;
	217
	218	if (!want_ingress)
c129412f	219	err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
ca22da2f DC	220	else if (is_mirred_nested())
ca22da2f DC	221	err = netif_rx(skb);
fa6d6399	222	else
	223	err = netif_receive_skb(skb);
	224
	225	return err;
	226	}
	227
871cf386 PT	228	TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,
	229	const struct tc_action *a,
	230	struct tcf_result *res)
1da177e4	231	{
a85a970a	232	struct tcf_mirred *m = to_mirred(a);
e5cf1baf	233	struct sk_buff *skb2 = skb;
53592b36	234	bool m_mac_header_xmit;
1da177e4	235	struct net_device *dev;
78dcdffe	236	unsigned int nest_level;
53592b36	237	int retval, err = 0;
e5cf1baf PA	238	bool use_reinsert;
	239	bool want_ingress;
	240	bool is_redirect;
70cf3dc7	241	bool expects_nh;
f799ada6	242	bool at_ingress;
53592b36 SL	243	int m_eaction;
53592b36 SL	244	int mac_len;
70cf3dc7	245	bool at_nh;
1da177e4	246
78dcdffe DC	247	nest_level = __this_cpu_inc_return(mirred_nest_level);
78dcdffe DC	248	if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {
e2ca070f JH	249	net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
e2ca070f JH	250	netdev_name(skb->dev));
78dcdffe	251	__this_cpu_dec(mirred_nest_level);
e2ca070f JH	252	return TC_ACT_SHOT;
	253	}
	254
2ee22a90	255	tcf_lastuse_update(&m->tcf_tm);
5e1ad95b	256	tcf_action_update_bstats(&m->common, skb);
1da177e4	257
53592b36 SL	258	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
53592b36 SL	259	m_eaction = READ_ONCE(m->tcfm_eaction);
2ee22a90	260	retval = READ_ONCE(m->tcf_action);
7fd4b288	261	dev = rcu_dereference_bh(m->tcfm_dev);
2ee22a90 ED	262	if (unlikely(!dev)) {
2ee22a90 ED	263	pr_notice_once("tc mirred: target device is gone\n");
3b87956e	264	goto out;
	265	}
	266
526f28bd	267	if (unlikely(!(dev->flags & IFF_UP)) \|\| !netif_carrier_ok(dev)) {
e87cc472 JP	268	net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
e87cc472 JP	269	dev->name);
feed1f17	270	goto out;
1da177e4 LT	271	}
1da177e4 LT	272
e5cf1baf PA	273	/* we could easily avoid the clone only if called by ingress and clsact;
	274	* since we can't easily detect the clsact caller, skip clone only for
	275	* ingress - that covers the TC S/W datapath.
	276	*/
	277	is_redirect = tcf_mirred_is_act_redirect(m_eaction);
f799ada6 XL	278	at_ingress = skb_at_tc_ingress(skb);
f799ada6 XL	279	use_reinsert = at_ingress && is_redirect &&
e5cf1baf PA	280	tcf_mirred_can_reinsert(retval);
	281	if (!use_reinsert) {
	282	skb2 = skb_clone(skb, GFP_ATOMIC);
	283	if (!skb2)
	284	goto out;
	285	}
1da177e4	286
f799ada6 XL	287	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
f799ada6 XL	288
d09c548d HL	289	/* All mirred/redirected skbs should clear previous ct info */
d09c548d HL	290	nf_reset_ct(skb2);
f799ada6 XL	291	if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */
f799ada6 XL	292	skb_dst_drop(skb2);
70cf3dc7 SL	293
	294	expects_nh = want_ingress \|\| !m_mac_header_xmit;
	295	at_nh = skb->data == skb_network_header(skb);
	296	if (at_nh != expects_nh) {
	297	mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
b3be9488	298	skb_network_offset(skb);
70cf3dc7 SL	299	if (expects_nh) {
70cf3dc7 SL	300	/* target device/action expect data at nh */
53592b36 SL	301	skb_pull_rcsum(skb2, mac_len);
53592b36 SL	302	} else {
70cf3dc7 SL	303	/* target device/action expect data at mac */
70cf3dc7 SL	304	skb_push_rcsum(skb2, mac_len);
53592b36	305	}
feed1f17	306	}
1da177e4	307
e5cf1baf PA	308	skb2->skb_iif = skb->dev->ifindex;
	309	skb2->dev = dev;
	310
1da177e4	311	/* mirror is always swallowed */
e5cf1baf	312	if (is_redirect) {
2c64605b PNA	313	skb_set_redirected(skb2, skb2->tc_at_ingress);
2c64605b PNA	314
e5cf1baf PA	315	/* let's the caller reinsert the packet, if possible */
e5cf1baf PA	316	if (use_reinsert) {
1d14b30b	317	err = tcf_mirred_forward(want_ingress, skb);
fa6d6399	318	if (err)
ef816f3c	319	tcf_action_inc_overlimit_qstats(&m->common);
78dcdffe	320	__this_cpu_dec(mirred_nest_level);
720f22fe	321	return TC_ACT_CONSUMED;
e5cf1baf	322	}
bc31c905	323	}
1da177e4	324
fa6d6399	325	err = tcf_mirred_forward(want_ingress, skb2);
feed1f17	326	if (err) {
2ee22a90	327	out:
26b537a8	328	tcf_action_inc_overlimit_qstats(&m->common);
53592b36	329	if (tcf_mirred_is_act_redirect(m_eaction))
16c0b164	330	retval = TC_ACT_SHOT;
2ee22a90	331	}
78dcdffe	332	__this_cpu_dec(mirred_nest_level);
feed1f17 CG	333
feed1f17 CG	334	return retval;
1da177e4 LT	335	}
1da177e4 LT	336
4b61d3e8 PL	337	static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
4b61d3e8 PL	338	u64 drops, u64 lastuse, bool hw)
9798e6fe	339	{
5712bf9c PB	340	struct tcf_mirred *m = to_mirred(a);
	341	struct tcf_t *tm = &m->tcf_tm;
	342
4b61d3e8	343	tcf_action_update_stats(a, bytes, packets, drops, hw);
3bb23421	344	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
9798e6fe JK	345	}
9798e6fe JK	346
5a7a5555 JHS	347	static int tcf_mirred_dump(struct sk_buff skb, struct tc_action a, int bind,
5a7a5555 JHS	348	int ref)
1da177e4	349	{
27a884dc	350	unsigned char *b = skb_tail_pointer(skb);
a85a970a	351	struct tcf_mirred *m = to_mirred(a);
1c40be12 ED	352	struct tc_mirred opt = {
1c40be12 ED	353	.index = m->tcf_index,
036bb443 VB	354	.refcnt = refcount_read(&m->tcf_refcnt) - ref,
036bb443 VB	355	.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
1c40be12	356	};
4e232818	357	struct net_device *dev;
1da177e4 LT	358	struct tcf_t t;
1da177e4 LT	359
653cd284	360	spin_lock_bh(&m->tcf_lock);
4e232818 VB	361	opt.action = m->tcf_action;
	362	opt.eaction = m->tcfm_eaction;
	363	dev = tcf_mirred_dev_dereference(m);
	364	if (dev)
	365	opt.ifindex = dev->ifindex;
	366
1b34ec43 DM	367	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
1b34ec43 DM	368	goto nla_put_failure;
48d8ee16 JHS	369
48d8ee16 JHS	370	tcf_tm_dump(&t, &m->tcf_tm);
9854518e	371	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
1b34ec43	372	goto nla_put_failure;
653cd284	373	spin_unlock_bh(&m->tcf_lock);
4e232818	374
1da177e4 LT	375	return skb->len;
1da177e4 LT	376
7ba699c6	377	nla_put_failure:
653cd284	378	spin_unlock_bh(&m->tcf_lock);
dc5fc579	379	nlmsg_trim(skb, b);
1da177e4 LT	380	return -1;
	381	}
	382
3b87956e	383	static int mirred_device_event(struct notifier_block *unused,
	384	unsigned long event, void *ptr)
	385	{
351638e7	386	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3b87956e	387	struct tcf_mirred *m;
3b87956e	388
2ee22a90	389	ASSERT_RTNL();
6bd00b85	390	if (event == NETDEV_UNREGISTER) {
4e232818	391	spin_lock(&mirred_list_lock);
3b87956e	392	list_for_each_entry(m, &mirred_list, tcfm_list) {
653cd284	393	spin_lock_bh(&m->tcf_lock);
4e232818	394	if (tcf_mirred_dev_dereference(m) == dev) {
d62607c3	395	netdev_put(dev, &m->tcfm_dev_tracker);
2ee22a90 ED	396	/* Note : no rcu grace period necessary, as
	397	* net_device are already rcu protected.
	398	*/
	399	RCU_INIT_POINTER(m->tcfm_dev, NULL);
3b87956e	400	}
653cd284	401	spin_unlock_bh(&m->tcf_lock);
3b87956e	402	}
4e232818	403	spin_unlock(&mirred_list_lock);
6bd00b85	404	}
3b87956e	405
	406	return NOTIFY_DONE;
	407	}
	408
	409	static struct notifier_block mirred_device_notifier = {
	410	.notifier_call = mirred_device_event,
	411	};
	412
470d5060 VB	413	static void tcf_mirred_dev_put(void *priv)
	414	{
	415	struct net_device *dev = priv;
	416
	417	dev_put(dev);
	418	}
	419
	420	static struct net_device *
	421	tcf_mirred_get_dev(const struct tc_action *a,
	422	tc_action_priv_destructor *destructor)
255cb304	423	{
843e79d0	424	struct tcf_mirred *m = to_mirred(a);
4e232818	425	struct net_device *dev;
84a75b32	426
4e232818 VB	427	rcu_read_lock();
4e232818 VB	428	dev = rcu_dereference(m->tcfm_dev);
470d5060	429	if (dev) {
84a75b32	430	dev_hold(dev);
470d5060 VB	431	*destructor = tcf_mirred_dev_put;
470d5060 VB	432	}
4e232818	433	rcu_read_unlock();
255cb304	434
84a75b32 VB	435	return dev;
	436	}
	437
b84b2d4e RM	438	static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
	439	{
	440	return nla_total_size(sizeof(struct tc_mirred));
	441	}
	442
c54e1d92 BZ	443	static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry,
	444	const struct tc_action *act)
	445	{
	446	entry->dev = act->ops->get_dev(act, &entry->destructor);
	447	if (!entry->dev)
	448	return;
	449	entry->destructor_priv = entry->dev;
	450	}
	451
	452	static int tcf_mirred_offload_act_setup(struct tc_action act, void entry_data,
c2ccf84e IS	453	u32 *index_inc, bool bind,
c2ccf84e IS	454	struct netlink_ext_ack *extack)
c54e1d92 BZ	455	{
	456	if (bind) {
	457	struct flow_action_entry *entry = entry_data;
	458
	459	if (is_tcf_mirred_egress_redirect(act)) {
	460	entry->id = FLOW_ACTION_REDIRECT;
	461	tcf_offload_mirred_get_dev(entry, act);
	462	} else if (is_tcf_mirred_egress_mirror(act)) {
	463	entry->id = FLOW_ACTION_MIRRED;
	464	tcf_offload_mirred_get_dev(entry, act);
	465	} else if (is_tcf_mirred_ingress_redirect(act)) {
	466	entry->id = FLOW_ACTION_REDIRECT_INGRESS;
	467	tcf_offload_mirred_get_dev(entry, act);
	468	} else if (is_tcf_mirred_ingress_mirror(act)) {
	469	entry->id = FLOW_ACTION_MIRRED_INGRESS;
	470	tcf_offload_mirred_get_dev(entry, act);
	471	} else {
4dcaa50d	472	NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload");
c54e1d92 BZ	473	return -EOPNOTSUPP;
	474	}
	475	*index_inc = 1;
	476	} else {
8cbfe939 BZ	477	struct flow_offload_action *fl_action = entry_data;
	478
	479	if (is_tcf_mirred_egress_redirect(act))
	480	fl_action->id = FLOW_ACTION_REDIRECT;
	481	else if (is_tcf_mirred_egress_mirror(act))
	482	fl_action->id = FLOW_ACTION_MIRRED;
	483	else if (is_tcf_mirred_ingress_redirect(act))
	484	fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
	485	else if (is_tcf_mirred_ingress_mirror(act))
	486	fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
	487	else
	488	return -EOPNOTSUPP;
c54e1d92 BZ	489	}
	490
	491	return 0;
	492	}
	493
1da177e4 LT	494	static struct tc_action_ops act_mirred_ops = {
1da177e4 LT	495	.kind = "mirred",
eddd2cf1	496	.id = TCA_ID_MIRRED,
1da177e4	497	.owner = THIS_MODULE,
7c5790c4	498	.act = tcf_mirred_act,
9798e6fe	499	.stats_update = tcf_stats_update,
1da177e4	500	.dump = tcf_mirred_dump,
86062033	501	.cleanup = tcf_mirred_release,
1da177e4	502	.init = tcf_mirred_init,
b84b2d4e	503	.get_fill_size = tcf_mirred_get_fill_size,
c54e1d92	504	.offload_act_setup = tcf_mirred_offload_act_setup,
a85a970a	505	.size = sizeof(struct tcf_mirred),
843e79d0	506	.get_dev = tcf_mirred_get_dev,
ddf97ccd WC	507	};
	508
	509	static __net_init int mirred_init_net(struct net *net)
	510	{
acd0a7ab	511	struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id);
ddf97ccd	512
981471bd	513	return tc_action_net_init(net, tn, &act_mirred_ops);
ddf97ccd WC	514	}
ddf97ccd WC	515
039af9c6	516	static void __net_exit mirred_exit_net(struct list_head *net_list)
ddf97ccd	517	{
acd0a7ab	518	tc_action_net_exit(net_list, act_mirred_ops.net_id);
ddf97ccd WC	519	}
	520
	521	static struct pernet_operations mirred_net_ops = {
	522	.init = mirred_init_net,
039af9c6	523	.exit_batch = mirred_exit_net,
acd0a7ab	524	.id = &act_mirred_ops.net_id,
ddf97ccd	525	.size = sizeof(struct tc_action_net),
1da177e4 LT	526	};
	527
	528	MODULE_AUTHOR("Jamal Hadi Salim(2002)");
	529	MODULE_DESCRIPTION("Device Mirror/redirect actions");
	530	MODULE_LICENSE("GPL");
	531
e9ce1cd3	532	static int __init mirred_init_module(void)
1da177e4	533	{
3b87956e	534	int err = register_netdevice_notifier(&mirred_device_notifier);
	535	if (err)
	536	return err;
	537
6ff9c364	538	pr_info("Mirror/redirect action on\n");
11c9a7d3 Y	539	err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
	540	if (err)
	541	unregister_netdevice_notifier(&mirred_device_notifier);
	542
	543	return err;
1da177e4 LT	544	}
1da177e4 LT	545
e9ce1cd3	546	static void __exit mirred_cleanup_module(void)
1da177e4	547	{
ddf97ccd	548	tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
568a153a	549	unregister_netdevice_notifier(&mirred_device_notifier);
1da177e4 LT	550	}
	551
	552	module_init(mirred_init_module);
	553	module_exit(mirred_cleanup_module);