// SPDX-License-Identifier: GPL-2.0-or-later

  /*

   * net/sched/act_simple.c	Simple example of an action

   *

   * Authors:	Jamal Hadi Salim (2005-8)

   */

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/init.h>

  #include <linux/kernel.h>

  #include <linux/skbuff.h>
  #include <linux/rtnetlink.h>

  #include <net/netlink.h>

  #include <net/pkt_sched.h>

  #include <net/pkt_cls.h>

  #include <linux/tc_act/tc_defact.h>
  #include <net/tc_act/tc_defact.h>

  static unsigned int simp_net_id;

  static struct tc_action_ops act_simp_ops;

  #define SIMP_MAX_DATA	32

  static int tcf_simp_act(struct sk_buff *skb, const struct tc_action *a,
  			struct tcf_result *res)

  {

  	struct tcf_defact *d = to_defact(a);

  	spin_lock(&d->tcf_lock);

  	tcf_lastuse_update(&d->tcf_tm);

  	bstats_update(&d->tcf_bstats, skb);

  	/* print policy string followed by _ then packet count
  	 * Example if this was the 3rd packet and the string was "hello"
  	 * then it would look like "hello_3" (without quotes)

  	 */

  	pr_info("simple: %s_%llu
  ",

  	       (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  	spin_unlock(&d->tcf_lock);
  	return d->tcf_action;
  }

  static void tcf_simp_release(struct tc_action *a)

  {

  	struct tcf_defact *d = to_defact(a);

  	kfree(d->tcfd_defdata);

  }

  static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)

  {

  	d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);

  	if (unlikely(!d->tcfd_defdata))
  		return -ENOMEM;

  	nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);

  	return 0;
  }

  static int reset_policy(struct tc_action *a, const struct nlattr *defdata,
  			struct tc_defact *p, struct tcf_proto *tp,
  			struct netlink_ext_ack *extack)

  {

  	struct tcf_chain *goto_ch = NULL;
  	struct tcf_defact *d;
  	int err;
  
  	err = tcf_action_check_ctrlact(p->action, tp, &goto_ch, extack);
  	if (err < 0)
  		return err;
  	d = to_defact(a);

  	spin_lock_bh(&d->tcf_lock);

  	goto_ch = tcf_action_set_ctrlact(a, p->action, goto_ch);

  	memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);

  	nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);

  	spin_unlock_bh(&d->tcf_lock);

  	if (goto_ch)
  		tcf_chain_put_by_act(goto_ch);
  	return 0;

  }

  static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },

  	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },

  };

  static int tcf_simp_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, simp_net_id);

  	struct nlattr *tb[TCA_DEF_MAX + 1];

  	struct tcf_chain *goto_ch = NULL;

  	struct tc_defact *parm;
  	struct tcf_defact *d;

  	bool exists = false;
  	int ret = 0, err;

  	u32 index;

  	if (nla == NULL)

  		return -EINVAL;

  	err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
  					  NULL);

  	if (err < 0)
  		return err;

  	if (tb[TCA_DEF_PARMS] == NULL)

  		return -EINVAL;

  	parm = nla_data(tb[TCA_DEF_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 (tb[TCA_DEF_DATA] == NULL) {
  		if (exists)

  			tcf_idr_release(*a, bind);

  		else

  			tcf_idr_cleanup(tn, index);

  		return -EINVAL;
  	}

  	if (!exists) {

  		ret = tcf_idr_create(tn, index, est, a,

  				     &act_simp_ops, bind, false, 0);

  		if (ret) {

  			tcf_idr_cleanup(tn, index);

  			return ret;

  		}

  		d = to_defact(*a);

  		err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
  					       extack);
  		if (err < 0)
  			goto release_idr;
  
  		err = alloc_defdata(d, tb[TCA_DEF_DATA]);
  		if (err < 0)
  			goto put_chain;
  
  		tcf_action_set_ctrlact(*a, parm->action, goto_ch);

  		ret = ACT_P_CREATED;
  	} else {

  		if (!ovr) {

  			err = -EEXIST;
  			goto release_idr;

  		}

  		err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
  		if (err)
  			goto release_idr;

  	}

  	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 int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
  			 int bind, int ref)

  {

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_defact *d = to_defact(a);

  	struct tc_defact opt = {
  		.index   = d->tcf_index,

  		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
  		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,

  	};

  	struct tcf_t t;

  	spin_lock_bh(&d->tcf_lock);
  	opt.action = d->tcf_action;

  	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
  	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
  		goto nla_put_failure;

  
  	tcf_tm_dump(&t, &d->tcf_tm);

  	if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))

  		goto nla_put_failure;

  	spin_unlock_bh(&d->tcf_lock);

  	return skb->len;

  nla_put_failure:

  	spin_unlock_bh(&d->tcf_lock);

  	nlmsg_trim(skb, b);

  	return -1;

  }

  static int tcf_simp_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, simp_net_id);

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

  }

  static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index)

  {
  	struct tc_action_net *tn = net_generic(net, simp_net_id);

  	return tcf_idr_search(tn, a, index);

  }

  static struct tc_action_ops act_simp_ops = {

  	.kind		=	"simple",

  	.id		=	TCA_ID_SIMP,

  	.owner		=	THIS_MODULE,

  	.act		=	tcf_simp_act,

  	.dump		=	tcf_simp_dump,

  	.cleanup	=	tcf_simp_release,

  	.init		=	tcf_simp_init,

  	.walk		=	tcf_simp_walker,
  	.lookup		=	tcf_simp_search,

  	.size		=	sizeof(struct tcf_defact),

  };
  
  static __net_init int simp_init_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, simp_net_id);

  	return tc_action_net_init(net, tn, &act_simp_ops);

  }

  static void __net_exit simp_exit_net(struct list_head *net_list)

  {

  	tc_action_net_exit(net_list, simp_net_id);

  }
  
  static struct pernet_operations simp_net_ops = {
  	.init = simp_init_net,

  	.exit_batch = simp_exit_net,

  	.id   = &simp_net_id,
  	.size = sizeof(struct tc_action_net),

  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2005)");
  MODULE_DESCRIPTION("Simple example action");
  MODULE_LICENSE("GPL");
  
  static int __init simp_init_module(void)
  {

  	int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);

  	if (!ret)

  		pr_info("Simple TC action Loaded
  ");

  	return ret;
  }
  
  static void __exit simp_cleanup_module(void)
  {

  	tcf_unregister_action(&act_simp_ops, &simp_net_ops);

  }
  
  module_init(simp_init_module);
  module_exit(simp_cleanup_module);