1 files changed, 520 insertions, 0 deletions

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
new file mode 100644
index 000000000..91a19460c
--- /dev/null
+++ b/net/sched/act_mirred.c
@@ -0,0 +1,520 @@
+// 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>
+
+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);
+	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 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 = dev_queue_xmit(skb);
+	else if (is_mirred_nested())
+		err = netif_rx(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 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_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_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 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);