[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/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,
			   u32 flags, 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;
	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 (!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);
		dev = rcu_replace_pointer(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);
	}

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

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

	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;
	bool expects_nh;
	int m_eaction;
	int mac_len;
	bool at_nh;

	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);
	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))) {
		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;
	}

	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);

	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_header(skb) - skb_mac_header(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) {
			res->ingress = want_ingress;
			err = tcf_mirred_forward(res->ingress, skb);
			if (err)
				tcf_action_inc_overlimit_qstats(&m->common);
			__this_cpu_dec(mirred_rec_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_rec_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 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 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 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,
};

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(net, 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");
	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>
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,
abbb0d33	96	u32 flags, 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;
7be8ef2c	107	u32 index;
1da177e4	108
1d4760c7 AA	109	if (!nla) {
1d4760c7 AA	110	NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
1da177e4	111	return -EINVAL;
1d4760c7	112	}
8cb08174 JB	113	ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
8cb08174 JB	114	mirred_policy, extack);
b76965e0 CG	115	if (ret < 0)
b76965e0 CG	116	return ret;
1d4760c7 AA	117	if (!tb[TCA_MIRRED_PARMS]) {
1d4760c7 AA	118	NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
1da177e4	119	return -EINVAL;
1d4760c7	120	}
7ba699c6	121	parm = nla_data(tb[TCA_MIRRED_PARMS]);
7be8ef2c DL	122	index = parm->index;
7be8ef2c DL	123	err = tcf_idr_check_alloc(tn, &index, a, bind);
0190c1d4 VB	124	if (err < 0)
	125	return err;
	126	exists = err;
87dfbdc6 JHS	127	if (exists && bind)
	128	return 0;
	129
b76965e0 CG	130	switch (parm->eaction) {
	131	case TCA_EGRESS_MIRROR:
	132	case TCA_EGRESS_REDIR:
53592b36 SL	133	case TCA_INGRESS_REDIR:
53592b36 SL	134	case TCA_INGRESS_MIRROR:
b76965e0 CG	135	break;
b76965e0 CG	136	default:
87dfbdc6	137	if (exists)
65a206c0	138	tcf_idr_release(*a, bind);
0190c1d4	139	else
7be8ef2c	140	tcf_idr_cleanup(tn, index);
1d4760c7	141	NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
b76965e0 CG	142	return -EINVAL;
b76965e0 CG	143	}
1da177e4	144
87dfbdc6	145	if (!exists) {
4e232818	146	if (!parm->ifindex) {
7be8ef2c	147	tcf_idr_cleanup(tn, index);
1d4760c7	148	NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
1da177e4	149	return -EINVAL;
1d4760c7	150	}
e3822678 VB	151	ret = tcf_idr_create_from_flags(tn, index, est, a,
e3822678 VB	152	&act_mirred_ops, bind, flags);
0190c1d4	153	if (ret) {
7be8ef2c	154	tcf_idr_cleanup(tn, index);
86062033	155	return ret;
0190c1d4	156	}
1da177e4	157	ret = ACT_P_CREATED;
4e8ddd7f	158	} else if (!ovr) {
65a206c0	159	tcf_idr_release(*a, bind);
4e8ddd7f	160	return -EEXIST;
1da177e4	161	}
064c5d68 JH	162
	163	m = to_mirred(*a);
	164	if (ret == ACT_P_CREATED)
	165	INIT_LIST_HEAD(&m->tcfm_list);
	166
ff9721d3 DC	167	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
	168	if (err < 0)
	169	goto release_idr;
	170
653cd284	171	spin_lock_bh(&m->tcf_lock);
4e232818 VB	172
	173	if (parm->ifindex) {
	174	dev = dev_get_by_index(net, parm->ifindex);
	175	if (!dev) {
653cd284	176	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	177	err = -ENODEV;
ff9721d3 DC	178	goto put_chain;
4e232818 VB	179	}
4e232818 VB	180	mac_header_xmit = dev_is_mac_header_xmit(dev);
445d3749 PM	181	dev = rcu_replace_pointer(m->tcfm_dev, dev,
445d3749 PM	182	lockdep_is_held(&m->tcf_lock));
4e232818 VB	183	if (dev)
4e232818 VB	184	dev_put(dev);
16577923	185	m->tcfm_mac_header_xmit = mac_header_xmit;
1da177e4	186	}
ff9721d3 DC	187	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
ff9721d3 DC	188	m->tcfm_eaction = parm->eaction;
653cd284	189	spin_unlock_bh(&m->tcf_lock);
ff9721d3 DC	190	if (goto_ch)
ff9721d3 DC	191	tcf_chain_put_by_act(goto_ch);
2ee22a90	192
3b87956e	193	if (ret == ACT_P_CREATED) {
4e232818	194	spin_lock(&mirred_list_lock);
3b87956e	195	list_add(&m->tcfm_list, &mirred_list);
4e232818	196	spin_unlock(&mirred_list_lock);
3b87956e	197	}
1da177e4	198
1da177e4	199	return ret;
ff9721d3 DC	200	put_chain:
	201	if (goto_ch)
	202	tcf_chain_put_by_act(goto_ch);
	203	release_idr:
	204	tcf_idr_release(*a, bind);
	205	return err;
1da177e4 LT	206	}
1da177e4 LT	207
fa6d6399	208	static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
	209	{
	210	int err;
	211
	212	if (!want_ingress)
	213	err = dev_queue_xmit(skb);
	214	else
	215	err = netif_receive_skb(skb);
	216
	217	return err;
	218	}
	219
7c5790c4 JHS	220	static int tcf_mirred_act(struct sk_buff skb, const struct tc_action a,
7c5790c4 JHS	221	struct tcf_result *res)
1da177e4	222	{
a85a970a	223	struct tcf_mirred *m = to_mirred(a);
e5cf1baf	224	struct sk_buff *skb2 = skb;
53592b36	225	bool m_mac_header_xmit;
1da177e4	226	struct net_device *dev;
e2ca070f	227	unsigned int rec_level;
53592b36	228	int retval, err = 0;
e5cf1baf PA	229	bool use_reinsert;
	230	bool want_ingress;
	231	bool is_redirect;
70cf3dc7	232	bool expects_nh;
53592b36 SL	233	int m_eaction;
53592b36 SL	234	int mac_len;
70cf3dc7	235	bool at_nh;
1da177e4	236
e2ca070f JH	237	rec_level = __this_cpu_inc_return(mirred_rec_level);
	238	if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
	239	net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
	240	netdev_name(skb->dev));
	241	__this_cpu_dec(mirred_rec_level);
	242	return TC_ACT_SHOT;
	243	}
	244
2ee22a90	245	tcf_lastuse_update(&m->tcf_tm);
5e1ad95b	246	tcf_action_update_bstats(&m->common, skb);
1da177e4	247
53592b36 SL	248	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
53592b36 SL	249	m_eaction = READ_ONCE(m->tcfm_eaction);
2ee22a90	250	retval = READ_ONCE(m->tcf_action);
7fd4b288	251	dev = rcu_dereference_bh(m->tcfm_dev);
2ee22a90 ED	252	if (unlikely(!dev)) {
2ee22a90 ED	253	pr_notice_once("tc mirred: target device is gone\n");
3b87956e	254	goto out;
	255	}
	256
2ee22a90	257	if (unlikely(!(dev->flags & IFF_UP))) {
e87cc472 JP	258	net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
e87cc472 JP	259	dev->name);
feed1f17	260	goto out;
1da177e4 LT	261	}
1da177e4 LT	262
e5cf1baf PA	263	/* we could easily avoid the clone only if called by ingress and clsact;
	264	* since we can't easily detect the clsact caller, skip clone only for
	265	* ingress - that covers the TC S/W datapath.
	266	*/
	267	is_redirect = tcf_mirred_is_act_redirect(m_eaction);
	268	use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
	269	tcf_mirred_can_reinsert(retval);
	270	if (!use_reinsert) {
	271	skb2 = skb_clone(skb, GFP_ATOMIC);
	272	if (!skb2)
	273	goto out;
	274	}
1da177e4	275
e5cf1baf	276	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
70cf3dc7 SL	277
	278	expects_nh = want_ingress \|\| !m_mac_header_xmit;
	279	at_nh = skb->data == skb_network_header(skb);
	280	if (at_nh != expects_nh) {
	281	mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :
	282	skb_network_header(skb) - skb_mac_header(skb);
	283	if (expects_nh) {
	284	/* target device/action expect data at nh */
53592b36 SL	285	skb_pull_rcsum(skb2, mac_len);
53592b36 SL	286	} else {
70cf3dc7 SL	287	/* target device/action expect data at mac */
70cf3dc7 SL	288	skb_push_rcsum(skb2, mac_len);
53592b36	289	}
feed1f17	290	}
1da177e4	291
e5cf1baf PA	292	skb2->skb_iif = skb->dev->ifindex;
	293	skb2->dev = dev;
	294
1da177e4	295	/* mirror is always swallowed */
e5cf1baf	296	if (is_redirect) {
2c64605b PNA	297	skb_set_redirected(skb2, skb2->tc_at_ingress);
2c64605b PNA	298
e5cf1baf PA	299	/* let's the caller reinsert the packet, if possible */
	300	if (use_reinsert) {
	301	res->ingress = want_ingress;
fa6d6399	302	err = tcf_mirred_forward(res->ingress, skb);
fa6d6399	303	if (err)
ef816f3c	304	tcf_action_inc_overlimit_qstats(&m->common);
e2ca070f	305	__this_cpu_dec(mirred_rec_level);
720f22fe	306	return TC_ACT_CONSUMED;
e5cf1baf	307	}
bc31c905	308	}
1da177e4	309
fa6d6399	310	err = tcf_mirred_forward(want_ingress, skb2);
feed1f17	311	if (err) {
2ee22a90	312	out:
26b537a8	313	tcf_action_inc_overlimit_qstats(&m->common);
53592b36	314	if (tcf_mirred_is_act_redirect(m_eaction))
16c0b164	315	retval = TC_ACT_SHOT;
2ee22a90	316	}
e2ca070f	317	__this_cpu_dec(mirred_rec_level);
feed1f17 CG	318
feed1f17 CG	319	return retval;
1da177e4 LT	320	}
1da177e4 LT	321
4b61d3e8 PL	322	static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets,
4b61d3e8 PL	323	u64 drops, u64 lastuse, bool hw)
9798e6fe	324	{
5712bf9c PB	325	struct tcf_mirred *m = to_mirred(a);
	326	struct tcf_t *tm = &m->tcf_tm;
	327
4b61d3e8	328	tcf_action_update_stats(a, bytes, packets, drops, hw);
3bb23421	329	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
9798e6fe JK	330	}
9798e6fe JK	331
5a7a5555 JHS	332	static int tcf_mirred_dump(struct sk_buff skb, struct tc_action a, int bind,
5a7a5555 JHS	333	int ref)
1da177e4	334	{
27a884dc	335	unsigned char *b = skb_tail_pointer(skb);
a85a970a	336	struct tcf_mirred *m = to_mirred(a);
1c40be12 ED	337	struct tc_mirred opt = {
1c40be12 ED	338	.index = m->tcf_index,
036bb443 VB	339	.refcnt = refcount_read(&m->tcf_refcnt) - ref,
036bb443 VB	340	.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
1c40be12	341	};
4e232818	342	struct net_device *dev;
1da177e4 LT	343	struct tcf_t t;
1da177e4 LT	344
653cd284	345	spin_lock_bh(&m->tcf_lock);
4e232818 VB	346	opt.action = m->tcf_action;
	347	opt.eaction = m->tcfm_eaction;
	348	dev = tcf_mirred_dev_dereference(m);
	349	if (dev)
	350	opt.ifindex = dev->ifindex;
	351
1b34ec43 DM	352	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
1b34ec43 DM	353	goto nla_put_failure;
48d8ee16 JHS	354
48d8ee16 JHS	355	tcf_tm_dump(&t, &m->tcf_tm);
9854518e	356	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
1b34ec43	357	goto nla_put_failure;
653cd284	358	spin_unlock_bh(&m->tcf_lock);
4e232818	359
1da177e4 LT	360	return skb->len;
1da177e4 LT	361
7ba699c6	362	nla_put_failure:
653cd284	363	spin_unlock_bh(&m->tcf_lock);
dc5fc579	364	nlmsg_trim(skb, b);
1da177e4 LT	365	return -1;
	366	}
	367
ddf97ccd WC	368	static int tcf_mirred_walker(struct net net, struct sk_buff skb,
ddf97ccd WC	369	struct netlink_callback *cb, int type,
41780105 AA	370	const struct tc_action_ops *ops,
41780105 AA	371	struct netlink_ext_ack *extack)
ddf97ccd WC	372	{
	373	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	374
b3620145	375	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
ddf97ccd WC	376	}
ddf97ccd WC	377
f061b48c	378	static int tcf_mirred_search(struct net net, struct tc_action *a, u32 index)
ddf97ccd WC	379	{
	380	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	381
65a206c0	382	return tcf_idr_search(tn, a, index);
ddf97ccd WC	383	}
ddf97ccd WC	384
3b87956e	385	static int mirred_device_event(struct notifier_block *unused,
	386	unsigned long event, void *ptr)
	387	{
351638e7	388	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3b87956e	389	struct tcf_mirred *m;
3b87956e	390
2ee22a90	391	ASSERT_RTNL();
6bd00b85	392	if (event == NETDEV_UNREGISTER) {
4e232818	393	spin_lock(&mirred_list_lock);
3b87956e	394	list_for_each_entry(m, &mirred_list, tcfm_list) {
653cd284	395	spin_lock_bh(&m->tcf_lock);
4e232818	396	if (tcf_mirred_dev_dereference(m) == dev) {
3b87956e	397	dev_put(dev);
2ee22a90 ED	398	/* Note : no rcu grace period necessary, as
	399	* net_device are already rcu protected.
	400	*/
	401	RCU_INIT_POINTER(m->tcfm_dev, NULL);
3b87956e	402	}
653cd284	403	spin_unlock_bh(&m->tcf_lock);
3b87956e	404	}
4e232818	405	spin_unlock(&mirred_list_lock);
6bd00b85	406	}
3b87956e	407
	408	return NOTIFY_DONE;
	409	}
	410
	411	static struct notifier_block mirred_device_notifier = {
	412	.notifier_call = mirred_device_event,
	413	};
	414
470d5060 VB	415	static void tcf_mirred_dev_put(void *priv)
	416	{
	417	struct net_device *dev = priv;
	418
	419	dev_put(dev);
	420	}
	421
	422	static struct net_device *
	423	tcf_mirred_get_dev(const struct tc_action *a,
	424	tc_action_priv_destructor *destructor)
255cb304	425	{
843e79d0	426	struct tcf_mirred *m = to_mirred(a);
4e232818	427	struct net_device *dev;
84a75b32	428
4e232818 VB	429	rcu_read_lock();
4e232818 VB	430	dev = rcu_dereference(m->tcfm_dev);
470d5060	431	if (dev) {
84a75b32	432	dev_hold(dev);
470d5060 VB	433	*destructor = tcf_mirred_dev_put;
470d5060 VB	434	}
4e232818	435	rcu_read_unlock();
255cb304	436
84a75b32 VB	437	return dev;
	438	}
	439
b84b2d4e RM	440	static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
	441	{
	442	return nla_total_size(sizeof(struct tc_mirred));
	443	}
	444
1da177e4 LT	445	static struct tc_action_ops act_mirred_ops = {
1da177e4 LT	446	.kind = "mirred",
eddd2cf1	447	.id = TCA_ID_MIRRED,
1da177e4	448	.owner = THIS_MODULE,
7c5790c4	449	.act = tcf_mirred_act,
9798e6fe	450	.stats_update = tcf_stats_update,
1da177e4	451	.dump = tcf_mirred_dump,
86062033	452	.cleanup = tcf_mirred_release,
1da177e4	453	.init = tcf_mirred_init,
ddf97ccd WC	454	.walk = tcf_mirred_walker,
ddf97ccd WC	455	.lookup = tcf_mirred_search,
b84b2d4e	456	.get_fill_size = tcf_mirred_get_fill_size,
a85a970a	457	.size = sizeof(struct tcf_mirred),
843e79d0	458	.get_dev = tcf_mirred_get_dev,
ddf97ccd WC	459	};
	460
	461	static __net_init int mirred_init_net(struct net *net)
	462	{
	463	struct tc_action_net *tn = net_generic(net, mirred_net_id);
	464
981471bd	465	return tc_action_net_init(net, tn, &act_mirred_ops);
ddf97ccd WC	466	}
ddf97ccd WC	467
039af9c6	468	static void __net_exit mirred_exit_net(struct list_head *net_list)
ddf97ccd	469	{
039af9c6	470	tc_action_net_exit(net_list, mirred_net_id);
ddf97ccd WC	471	}
	472
	473	static struct pernet_operations mirred_net_ops = {
	474	.init = mirred_init_net,
039af9c6	475	.exit_batch = mirred_exit_net,
ddf97ccd WC	476	.id = &mirred_net_id,
ddf97ccd WC	477	.size = sizeof(struct tc_action_net),
1da177e4 LT	478	};
	479
	480	MODULE_AUTHOR("Jamal Hadi Salim(2002)");
	481	MODULE_DESCRIPTION("Device Mirror/redirect actions");
	482	MODULE_LICENSE("GPL");
	483
e9ce1cd3	484	static int __init mirred_init_module(void)
1da177e4	485	{
3b87956e	486	int err = register_netdevice_notifier(&mirred_device_notifier);
	487	if (err)
	488	return err;
	489
6ff9c364	490	pr_info("Mirror/redirect action on\n");
11c9a7d3 Y	491	err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
	492	if (err)
	493	unregister_netdevice_notifier(&mirred_device_notifier);
	494
	495	return err;
1da177e4 LT	496	}
1da177e4 LT	497
e9ce1cd3	498	static void __exit mirred_cleanup_module(void)
1da177e4	499	{
ddf97ccd	500	tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
568a153a	501	unregister_netdevice_notifier(&mirred_device_notifier);
1da177e4 LT	502	}
	503
	504	module_init(mirred_init_module);
	505	module_exit(mirred_cleanup_module);