path: root/net/sched/act_api.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/act_api.c	Packet action API.
 *
 * Author:	Jamal Hadi Salim
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/err.h>
#include <linux/module.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/sch_generic.h>
#include <net/pkt_cls.h>
#include <net/act_api.h>
#include <net/netlink.h>

static void tcf_action_goto_chain_exec(const struct tc_action *a,
				       struct tcf_result *res)
{
	const struct tcf_chain *chain = rcu_dereference_bh(a->goto_chain);

	res->goto_tp = rcu_dereference_bh(chain->filter_chain);
}

static void tcf_free_cookie_rcu(struct rcu_head *p)
{
	struct tc_cookie *cookie = container_of(p, struct tc_cookie, rcu);

	kfree(cookie->data);
	kfree(cookie);
}

static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie,
				  struct tc_cookie *new_cookie)
{
	struct tc_cookie *old;

	old = xchg((__force struct tc_cookie **)old_cookie, new_cookie);
	if (old)
		call_rcu(&old->rcu, tcf_free_cookie_rcu);
}

int tcf_action_check_ctrlact(int action, struct tcf_proto *tp,
			     struct tcf_chain **newchain,
			     struct netlink_ext_ack *extack)
{
	int opcode = TC_ACT_EXT_OPCODE(action), ret = -EINVAL;
	u32 chain_index;

	if (!opcode)
		ret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;
	else if (opcode <= TC_ACT_EXT_OPCODE_MAX || action == TC_ACT_UNSPEC)
		ret = 0;
	if (ret) {
		NL_SET_ERR_MSG(extack, "invalid control action");
		goto end;
	}

	if (TC_ACT_EXT_CMP(action, TC_ACT_GOTO_CHAIN)) {
		chain_index = action & TC_ACT_EXT_VAL_MASK;
		if (!tp || !newchain) {
			ret = -EINVAL;
			NL_SET_ERR_MSG(extack,
				       "can't goto NULL proto/chain");
			goto end;
		}
		*newchain = tcf_chain_get_by_act(tp->chain->block, chain_index);
		if (!*newchain) {
			ret = -ENOMEM;
			NL_SET_ERR_MSG(extack,
				       "can't allocate goto_chain");
		}
	}
end:
	return ret;
}
EXPORT_SYMBOL(tcf_action_check_ctrlact);

struct tcf_chain *tcf_action_set_ctrlact(struct tc_action *a, int action,
					 struct tcf_chain *goto_chain)
{
	a->tcfa_action = action;
	goto_chain = rcu_replace_pointer(a->goto_chain, goto_chain, 1);
	return goto_chain;
}
EXPORT_SYMBOL(tcf_action_set_ctrlact);

/* XXX: For standalone actions, we don't need a RCU grace period either, because
 * actions are always connected to filters and filters are already destroyed in
 * RCU callbacks, so after a RCU grace period actions are already disconnected
 * from filters. Readers later can not find us.
 */
static void free_tcf(struct tc_action *p)
{
	struct tcf_chain *chain = rcu_dereference_protected(p->goto_chain, 1);

	free_percpu(p->cpu_bstats);
	free_percpu(p->cpu_bstats_hw);
	free_percpu(p->cpu_qstats);

	tcf_set_action_cookie(&p->act_cookie, NULL);
	if (chain)
		tcf_chain_put_by_act(chain);

	kfree(p);
}

static void tcf_action_cleanup(struct tc_action *p)
{
	if (p->ops->cleanup)
		p->ops->cleanup(p);

	gen_kill_estimator(&p->tcfa_rate_est);
	free_tcf(p);
}

static int __tcf_action_put(struct tc_action *p, bool bind)
{
	struct tcf_idrinfo *idrinfo = p->idrinfo;

	if (refcount_dec_and_mutex_lock(&p->tcfa_refcnt, &idrinfo->lock)) {
		if (bind)
			atomic_dec(&p->tcfa_bindcnt);
		idr_remove(&idrinfo->action_idr, p->tcfa_index);
		mutex_unlock(&idrinfo->lock);

		tcf_action_cleanup(p);
		return 1;
	}

	if (bind)
		atomic_dec(&p->tcfa_bindcnt);

	return 0;
}

int __tcf_idr_release(struct tc_action *p, bool