net/sched/act_sample.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * net/sched/act_sample.c - Packet sampling tc action
  * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
  */

 #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 <net/net_namespace.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <linux/tc_act/tc_sample.h>
 #include <net/tc_act/tc_sample.h>
 #include <net/psample.h>
 #include <net/pkt_cls.h>

 #include <linux/if_arp.h>

 static unsigned int sample_net_id;
 static struct tc_action_ops act_sample_ops;

 static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
 	[TCA_SAMPLE_PARMS]		= { .len = sizeof(struct tc_sample) },
 	[TCA_SAMPLE_RATE]		= { .type = NLA_U32 },
 	[TCA_SAMPLE_TRUNC_SIZE]		= { .type = NLA_U32 },
 	[TCA_SAMPLE_PSAMPLE_GROUP]	= { .type = NLA_U32 },
 };

 static int tcf_sample_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, sample_net_id);
 	struct nlattr *tb[TCA_SAMPLE_MAX + 1];
 	struct psample_group *psample_group;
 	u32 psample_group_num, rate, index;
 	struct tcf_chain *goto_ch = NULL;
 	struct tc_sample *parm;
 	struct tcf_sample *s;
 	bool exists = false;
 	int ret, err;

 	if (!nla)
 		return -EINVAL;
 	ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
 					  sample_policy, NULL);
 	if (ret < 0)
 		return ret;
 	if (!tb[TCA_SAMPLE_PARMS] || !tb[TCA_SAMPLE_RATE] ||
 	    !tb[TCA_SAMPLE_PSAMPLE_GROUP])
 		return -EINVAL;

 	parm = nla_data(tb[TCA_SAMPLE_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;

 	if (!exists) {
 		ret = tcf_idr_create(tn, index, est, a,
 				     &act_sample_ops, bind, true);
 		if (ret) {
 			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
 		return -EEXIST;
 	}
 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 	if (err < 0)
 		goto release_idr;

 	rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
 	if (!rate) {
 		NL_SET_ERR_MSG(extack, "invalid sample rate");
 		err = -EINVAL;
 		goto put_chain;
 	}
 	psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
 	psample_group = psample_group_get(net, psample_group_num);
 	if (!psample_group) {
 		err = -ENOMEM;
 		goto put_chain;
 	}

 	s = to_sample(*a);

 	spin_lock_bh(&s->tcf_lock);
 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 	s->rate = rate;
 	s->psample_group_num = psample_group_num;
 	rcu_swap_protected(s->psample_group, psample_group,
 			   lockdep_is_held(&s->tcf_lock));

 	if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
 		s->truncate = true;
 		s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
 	}
 	spin_unlock_bh(&s->tcf_lock);

 	if (psample_group)
 		psample_group_put(psample_group);
 	if (goto_ch)
 		tcf_chain_put_by_act(goto_ch);

 	if (ret == ACT_P_CREATED)
 		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 void tcf_sample_cleanup(struct tc_action *a)
 {
 	struct tcf_sample *s = to_sample(a);
 	struct psample_group *psample_group;

 	/* last reference to action, no need to lock */
 	psample_group = rcu_dereference_protected(s->psample_group, 1);
 	RCU_INIT_POINTER(s->psample_group, NULL);
 	if (psample_group)
 		psample_group_put(psample_group);
 }

 static bool tcf_sample_dev_ok_push(struct net_device *dev)
 {
 	switch (dev->type) {
 	case ARPHRD_TUNNEL:
 	case ARPHRD_TUNNEL6:
 	case ARPHRD_SIT:
 	case ARPHRD_IPGRE:
 	case ARPHRD_IP6GRE:
 	case ARPHRD_VOID:
 	case ARPHRD_NONE:
 		return false;
 	default:
 		return true;
 	}
 }

 static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
 			  struct tcf_result *res)
 {
 	struct tcf_sample *s = to_sample(a);
 	struct psample_group *psample_group;
 	int retval;
 	int size;
 	int iif;
 	int oif;

 	tcf_lastuse_update(&s->tcf_tm);
 	bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
 	retval = READ_ONCE(s->tcf_action);

 	psample_group = rcu_dereference_bh(s->psample_group);

 	/* randomly sample packets according to rate */
 	if (psample_group && (prandom_u32() % s->rate == 0)) {
 		if (!skb_at_tc_ingress(skb)) {
 			iif = skb->skb_iif;
 			oif = skb->dev->ifindex;
 		} else {
 			iif = skb->dev->ifindex;
 			oif = 0;
 		}

 		/* on ingress, the mac header gets popped, so push it back */
 		if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
 			skb_push(skb, skb->mac_len);

 		size = s->truncate ? s->trunc_size : skb->len;
 		psample_sample_packet(psample_group, skb, size, iif, oif,
 				      s->rate);

 		if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
 			skb_pull(skb, skb->mac_len);
 	}

 	return retval;
 }

 static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
 			   int bind, int ref)
 {
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tcf_sample *s = to_sample(a);
 	struct tc_sample opt = {
 		.index      = s->tcf_index,
 		.refcnt     = refcount_read(&s->tcf_refcnt) - ref,
 		.bindcnt    = atomic_read(&s->tcf_bindcnt) - bind,
 	};
 	struct tcf_t t;

 	spin_lock_bh(&s->tcf_lock);
 	opt.action = s->tcf_action;
 	if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;

 	tcf_tm_dump(&t, &s->tcf_tm);
 	if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
 		goto nla_put_failure;

 	if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
 		goto nla_put_failure;

 	if (s->truncate)
 		if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
 			goto nla_put_failure;

 	if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
 		goto nla_put_failure;
 	spin_unlock_bh(&s->tcf_lock);

 	return skb->len;

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

 static int tcf_sample_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, sample_net_id);

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

 static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index)
 {
 	struct tc_action_net *tn = net_generic(net, sample_net_id);

 	return tcf_idr_search(tn, a, index);
 }

 static void tcf_psample_group_put(void *priv)
 {
 	struct psample_group *group = priv;

 	psample_group_put(group);
 }

 static struct psample_group *
 tcf_sample_get_group(const struct tc_action *a,
 		     tc_action_priv_destructor *destructor)
 {
 	struct tcf_sample *s = to_sample(a);
 	struct psample_group *group;

 	spin_lock_bh(&s->tcf_lock);
 	group = rcu_dereference_protected(s->psample_group,
 					  lockdep_is_held(&s->tcf_lock));
 	if (group) {
 		psample_group_take(group);
 		*destructor = tcf_psample_group_put;
 	}
 	spin_unlock_bh(&s->tcf_lock);

 	return group;
 }

 static struct tc_action_ops act_sample_ops = {
 	.kind	  = "sample",
 	.id	  = TCA_ID_SAMPLE,
 	.owner	  = THIS_MODULE,
 	.act	  = tcf_sample_act,
 	.dump	  = tcf_sample_dump,
 	.init	  = tcf_sample_init,
 	.cleanup  = tcf_sample_cleanup,
 	.walk	  = tcf_sample_walker,
 	.lookup	  = tcf_sample_search,
 	.get_psample_group = tcf_sample_get_group,
 	.size	  = sizeof(struct tcf_sample),
 };

 static __net_init int sample_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, sample_net_id);

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

 static void __net_exit sample_exit_net(struct list_head *net_list)
 {
 	tc_action_net_exit(net_list, sample_net_id);
 }

 static struct pernet_operations sample_net_ops = {
 	.init = sample_init_net,
 	.exit_batch = sample_exit_net,
 	.id   = &sample_net_id,
 	.size = sizeof(struct tc_action_net),
 };

 static int __init sample_init_module(void)
 {
 	return tcf_register_action(&act_sample_ops, &sample_net_ops);
 }

 static void __exit sample_cleanup_module(void)
 {
 	tcf_unregister_action(&act_sample_ops, &sample_net_ops);
 }

 module_init(sample_init_module);
 module_exit(sample_cleanup_module);

 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
 MODULE_DESCRIPTION("Packet sampling action");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* net/sched/act_sample.c - Packet sampling tc action
	* Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
	*/

	#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 <net/net_namespace.h>
	#include <net/netlink.h>
	#include <net/pkt_sched.h>
	#include <linux/tc_act/tc_sample.h>
	#include <net/tc_act/tc_sample.h>
	#include <net/psample.h>
	#include <net/pkt_cls.h>

	#include <linux/if_arp.h>

	static unsigned int sample_net_id;
	static struct tc_action_ops act_sample_ops;

	static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
	[TCA_SAMPLE_PARMS] = { .len = sizeof(struct tc_sample) },
	[TCA_SAMPLE_RATE] = { .type = NLA_U32 },
	[TCA_SAMPLE_TRUNC_SIZE] = { .type = NLA_U32 },
	[TCA_SAMPLE_PSAMPLE_GROUP] = { .type = NLA_U32 },
	};

	static int tcf_sample_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, sample_net_id);
	struct nlattr *tb[TCA_SAMPLE_MAX + 1];
	struct psample_group *psample_group;
	u32 psample_group_num, rate, index;
	struct tcf_chain *goto_ch = NULL;
	struct tc_sample *parm;
	struct tcf_sample *s;
	bool exists = false;
	int ret, err;

	if (!nla)
	return -EINVAL;
	ret = nla_parse_nested_deprecated(tb, TCA_SAMPLE_MAX, nla,
	sample_policy, NULL);
	if (ret < 0)
	return ret;
	if (!tb[TCA_SAMPLE_PARMS] \|\| !tb[TCA_SAMPLE_RATE] \|\|
	!tb[TCA_SAMPLE_PSAMPLE_GROUP])
	return -EINVAL;

	parm = nla_data(tb[TCA_SAMPLE_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;

	if (!exists) {
	ret = tcf_idr_create(tn, index, est, a,
	&act_sample_ops, bind, true);
	if (ret) {
	tcf_idr_cleanup(tn, index);
	return ret;
	}
	ret = ACT_P_CREATED;
	} else if (!ovr) {
	tcf_idr_release(*a, bind);
	return -EEXIST;
	}
	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
	if (err < 0)
	goto release_idr;

	rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
	if (!rate) {
	NL_SET_ERR_MSG(extack, "invalid sample rate");
	err = -EINVAL;
	goto put_chain;
	}
	psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
	psample_group = psample_group_get(net, psample_group_num);
	if (!psample_group) {
	err = -ENOMEM;
	goto put_chain;
	}

	s = to_sample(*a);

	spin_lock_bh(&s->tcf_lock);
	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
	s->rate = rate;
	s->psample_group_num = psample_group_num;
	rcu_swap_protected(s->psample_group, psample_group,
	lockdep_is_held(&s->tcf_lock));

	if (tb[TCA_SAMPLE_TRUNC_SIZE]) {
	s->truncate = true;
	s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
	}
	spin_unlock_bh(&s->tcf_lock);

	if (psample_group)
	psample_group_put(psample_group);
	if (goto_ch)
	tcf_chain_put_by_act(goto_ch);

	if (ret == ACT_P_CREATED)
	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 void tcf_sample_cleanup(struct tc_action *a)
	{
	struct tcf_sample *s = to_sample(a);
	struct psample_group *psample_group;

	/* last reference to action, no need to lock */
	psample_group = rcu_dereference_protected(s->psample_group, 1);
	RCU_INIT_POINTER(s->psample_group, NULL);
	if (psample_group)
	psample_group_put(psample_group);
	}

	static bool tcf_sample_dev_ok_push(struct net_device *dev)
	{
	switch (dev->type) {
	case ARPHRD_TUNNEL:
	case ARPHRD_TUNNEL6:
	case ARPHRD_SIT:
	case ARPHRD_IPGRE:
	case ARPHRD_IP6GRE:
	case ARPHRD_VOID:
	case ARPHRD_NONE:
	return false;
	default:
	return true;
	}
	}

	static int tcf_sample_act(struct sk_buff skb, const struct tc_action a,
	struct tcf_result *res)
	{
	struct tcf_sample *s = to_sample(a);
	struct psample_group *psample_group;
	int retval;
	int size;
	int iif;
	int oif;

	tcf_lastuse_update(&s->tcf_tm);
	bstats_cpu_update(this_cpu_ptr(s->common.cpu_bstats), skb);
	retval = READ_ONCE(s->tcf_action);

	psample_group = rcu_dereference_bh(s->psample_group);

	/* randomly sample packets according to rate */
	if (psample_group && (prandom_u32() % s->rate == 0)) {
	if (!skb_at_tc_ingress(skb)) {
	iif = skb->skb_iif;
	oif = skb->dev->ifindex;
	} else {
	iif = skb->dev->ifindex;
	oif = 0;
	}

	/* on ingress, the mac header gets popped, so push it back */
	if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
	skb_push(skb, skb->mac_len);

	size = s->truncate ? s->trunc_size : skb->len;
	psample_sample_packet(psample_group, skb, size, iif, oif,
	s->rate);

	if (skb_at_tc_ingress(skb) && tcf_sample_dev_ok_push(skb->dev))
	skb_pull(skb, skb->mac_len);
	}

	return retval;
	}

	static int tcf_sample_dump(struct sk_buff skb, struct tc_action a,
	int bind, int ref)
	{
	unsigned char *b = skb_tail_pointer(skb);
	struct tcf_sample *s = to_sample(a);
	struct tc_sample opt = {
	.index = s->tcf_index,
	.refcnt = refcount_read(&s->tcf_refcnt) - ref,
	.bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
	};
	struct tcf_t t;

	spin_lock_bh(&s->tcf_lock);
	opt.action = s->tcf_action;
	if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
	goto nla_put_failure;

	tcf_tm_dump(&t, &s->tcf_tm);
	if (nla_put_64bit(skb, TCA_SAMPLE_TM, sizeof(t), &t, TCA_SAMPLE_PAD))
	goto nla_put_failure;

	if (nla_put_u32(skb, TCA_SAMPLE_RATE, s->rate))
	goto nla_put_failure;

	if (s->truncate)
	if (nla_put_u32(skb, TCA_SAMPLE_TRUNC_SIZE, s->trunc_size))
	goto nla_put_failure;

	if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
	goto nla_put_failure;
	spin_unlock_bh(&s->tcf_lock);

	return skb->len;

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

	static int tcf_sample_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, sample_net_id);

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

	static int tcf_sample_search(struct net net, struct tc_action *a, u32 index)
	{
	struct tc_action_net *tn = net_generic(net, sample_net_id);

	return tcf_idr_search(tn, a, index);
	}

	static void tcf_psample_group_put(void *priv)
	{
	struct psample_group *group = priv;

	psample_group_put(group);
	}

	static struct psample_group *
	tcf_sample_get_group(const struct tc_action *a,
	tc_action_priv_destructor *destructor)
	{
	struct tcf_sample *s = to_sample(a);
	struct psample_group *group;

	spin_lock_bh(&s->tcf_lock);
	group = rcu_dereference_protected(s->psample_group,
	lockdep_is_held(&s->tcf_lock));
	if (group) {
	psample_group_take(group);
	*destructor = tcf_psample_group_put;
	}
	spin_unlock_bh(&s->tcf_lock);

	return group;
	}

	static struct tc_action_ops act_sample_ops = {
	.kind = "sample",
	.id = TCA_ID_SAMPLE,
	.owner = THIS_MODULE,
	.act = tcf_sample_act,
	.dump = tcf_sample_dump,
	.init = tcf_sample_init,
	.cleanup = tcf_sample_cleanup,
	.walk = tcf_sample_walker,
	.lookup = tcf_sample_search,
	.get_psample_group = tcf_sample_get_group,
	.size = sizeof(struct tcf_sample),
	};

	static __net_init int sample_init_net(struct net *net)
	{
	struct tc_action_net *tn = net_generic(net, sample_net_id);

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

	static void __net_exit sample_exit_net(struct list_head *net_list)
	{
	tc_action_net_exit(net_list, sample_net_id);
	}

	static struct pernet_operations sample_net_ops = {
	.init = sample_init_net,
	.exit_batch = sample_exit_net,
	.id = &sample_net_id,
	.size = sizeof(struct tc_action_net),
	};

	static int __init sample_init_module(void)
	{
	return tcf_register_action(&act_sample_ops, &sample_net_ops);
	}

	static void __exit sample_cleanup_module(void)
	{
	tcf_unregister_action(&act_sample_ops, &sample_net_ops);
	}

	module_init(sample_init_module);
	module_exit(sample_cleanup_module);

	MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
	MODULE_DESCRIPTION("Packet sampling action");
	MODULE_LICENSE("GPL v2");