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

  /*

   * net/sched/act_gact.c		Generic actions

   *

   * copyright 	Jamal Hadi Salim (2002-4)

   */

  #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 <net/netlink.h>

  #include <net/pkt_sched.h>

  #include <net/pkt_cls.h>

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

  static unsigned int gact_net_id;

  static struct tc_action_ops act_gact_ops;

  #ifdef CONFIG_GACT_PROB

  static int gact_net_rand(struct tcf_gact *gact)

  {

  	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  	if (prandom_u32() % gact->tcfg_pval)

  		return gact->tcf_action;
  	return gact->tcfg_paction;

  }

  static int gact_determ(struct tcf_gact *gact)

  {

  	u32 pack = atomic_inc_return(&gact->packets);

  	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */

  	if (pack % gact->tcfg_pval)

  		return gact->tcf_action;
  	return gact->tcfg_paction;

  }

  typedef int (*g_rand)(struct tcf_gact *gact);

  static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };

  #endif /* CONFIG_GACT_PROB */

  static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  	[TCA_GACT_PARMS]	= { .len = sizeof(struct tc_gact) },
  	[TCA_GACT_PROB]		= { .len = sizeof(struct tc_gact_p) },
  };

  static int tcf_gact_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, gact_net_id);

  	struct nlattr *tb[TCA_GACT_MAX + 1];

  	struct tcf_chain *goto_ch = NULL;

  	struct tc_gact *parm;

  	struct tcf_gact *gact;

  	int ret = 0;

  	u32 index;

  	int err;

  #ifdef CONFIG_GACT_PROB
  	struct tc_gact_p *p_parm = NULL;
  #endif

  	if (nla == NULL)

  		return -EINVAL;

  	err = nla_parse_nested_deprecated(tb, TCA_GACT_MAX, nla, gact_policy,
  					  NULL);

  	if (err < 0)
  		return err;

  	if (tb[TCA_GACT_PARMS] == NULL)

  		return -EINVAL;

  	parm = nla_data(tb[TCA_GACT_PARMS]);

  	index = parm->index;

  #ifndef CONFIG_GACT_PROB

  	if (tb[TCA_GACT_PROB] != NULL)

  		return -EOPNOTSUPP;

  #else
  	if (tb[TCA_GACT_PROB]) {
  		p_parm = nla_data(tb[TCA_GACT_PROB]);
  		if (p_parm->ptype >= MAX_RAND)
  			return -EINVAL;

  		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
  			NL_SET_ERR_MSG(extack,
  				       "goto chain not allowed on fallback");
  			return -EINVAL;
  		}

  	}

  #endif

  	err = tcf_idr_check_alloc(tn, &index, a, bind);

  	if (!err) {

  		ret = tcf_idr_create_from_flags(tn, index, est, a,
  						&act_gact_ops, bind, flags);

  		if (ret) {

  			tcf_idr_cleanup(tn, index);

  			return ret;

  		}

  		ret = ACT_P_CREATED;

  	} else if (err > 0) {

  		if (bind)/* dont override defaults */
  			return 0;

  		if (!ovr) {
  			tcf_idr_release(*a, bind);

  			return -EEXIST;

  		}

  	} else {
  		return err;

  	}

  	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
  	if (err < 0)
  		goto release_idr;

  	gact = to_gact(*a);

  	spin_lock_bh(&gact->tcf_lock);

  	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);

  #ifdef CONFIG_GACT_PROB

  	if (p_parm) {

  		gact->tcfg_paction = p_parm->paction;

  		gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
  		/* Make sure tcfg_pval is written before tcfg_ptype
  		 * coupled with smp_rmb() in gact_net_rand() & gact_determ()
  		 */
  		smp_wmb();

  		gact->tcfg_ptype   = p_parm->ptype;

  	}
  #endif

  	spin_unlock_bh(&gact->tcf_lock);

  	if (goto_ch)
  		tcf_chain_put_by_act(goto_ch);

  	return ret;

  release_idr:
  	tcf_idr_release(*a, bind);
  	return err;

  }

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

  {

  	struct tcf_gact *gact = to_gact(a);

  	int action = READ_ONCE(gact->tcf_action);

  #ifdef CONFIG_GACT_PROB

  	{
  	u32 ptype = READ_ONCE(gact->tcfg_ptype);
  
  	if (ptype)
  		action = gact_rand[ptype](gact);
  	}

  #endif

  	tcf_action_update_bstats(&gact->common, skb);

  	if (action == TC_ACT_SHOT)

  		tcf_action_inc_drop_qstats(&gact->common);

  
  	tcf_lastuse_update(&gact->tcf_tm);

  
  	return action;
  }

  static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u64 packets,
  				  u64 drops, u64 lastuse, bool hw)

  {

  	struct tcf_gact *gact = to_gact(a);

  	int action = READ_ONCE(gact->tcf_action);
  	struct tcf_t *tm = &gact->tcf_tm;

  	tcf_action_update_stats(a, bytes, packets,
  				action == TC_ACT_SHOT ? packets : drops, hw);

  	tm->lastuse = max_t(u64, tm->lastuse, lastuse);

  }

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

  {

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_gact *gact = to_gact(a);

  	struct tc_gact opt = {
  		.index   = gact->tcf_index,

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

  	};

  	struct tcf_t t;

  	spin_lock_bh(&gact->tcf_lock);

  	opt.action = gact->tcf_action;

  	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
  		goto nla_put_failure;

  #ifdef CONFIG_GACT_PROB

  	if (gact->tcfg_ptype) {

  		struct tc_gact_p p_opt = {
  			.paction = gact->tcfg_paction,
  			.pval    = gact->tcfg_pval,
  			.ptype   = gact->tcfg_ptype,
  		};

  		if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
  			goto nla_put_failure;

  	}
  #endif

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

  	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))

  		goto nla_put_failure;

  	spin_unlock_bh(&gact->tcf_lock);

  	return skb->len;

  nla_put_failure:

  	spin_unlock_bh(&gact->tcf_lock);

  	nlmsg_trim(skb, b);

  	return -1;
  }

  static int tcf_gact_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, gact_net_id);

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

  }

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

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

  	return tcf_idr_search(tn, a, index);

  }

  static size_t tcf_gact_get_fill_size(const struct tc_action *act)
  {
  	size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
  
  #ifdef CONFIG_GACT_PROB
  	if (to_gact(act)->tcfg_ptype)
  		/* TCA_GACT_PROB */
  		sz += nla_total_size(sizeof(struct tc_gact_p));
  #endif
  
  	return sz;
  }

  static struct tc_action_ops act_gact_ops = {
  	.kind		=	"gact",

  	.id		=	TCA_ID_GACT,

  	.owner		=	THIS_MODULE,

  	.act		=	tcf_gact_act,

  	.stats_update	=	tcf_gact_stats_update,

  	.dump		=	tcf_gact_dump,

  	.init		=	tcf_gact_init,

  	.walk		=	tcf_gact_walker,
  	.lookup		=	tcf_gact_search,

  	.get_fill_size	=	tcf_gact_get_fill_size,

  	.size		=	sizeof(struct tcf_gact),

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

  	return tc_action_net_init(net, tn, &act_gact_ops);

  }

  static void __net_exit gact_exit_net(struct list_head *net_list)

  {

  	tc_action_net_exit(net_list, gact_net_id);

  }
  
  static struct pernet_operations gact_net_ops = {
  	.init = gact_init_net,

  	.exit_batch = gact_exit_net,

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

  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
  MODULE_DESCRIPTION("Generic Classifier actions");
  MODULE_LICENSE("GPL");

  static int __init gact_init_module(void)

  {
  #ifdef CONFIG_GACT_PROB

  	pr_info("GACT probability on
  ");

  #else

  	pr_info("GACT probability NOT on
  ");

  #endif

  
  	return tcf_register_action(&act_gact_ops, &gact_net_ops);

  }

  static void __exit gact_cleanup_module(void)

  {

  	tcf_unregister_action(&act_gact_ops, &gact_net_ops);

  }
  
  module_init(gact_init_module);
  module_exit(gact_cleanup_module);