/*
   * net/sched/simp.c	Simple example of an action
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   *
   * 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>
  
  #define TCA_ACT_SIMP 22
  
  #include <linux/tc_act/tc_defact.h>
  #include <net/tc_act/tc_defact.h>
  
  #define SIMP_TAB_MASK     7
  static struct tcf_hashinfo simp_hash_info;
  
  #define SIMP_MAX_DATA	32
  static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  		    struct tcf_result *res)
  {
  	struct tcf_defact *d = a->priv;
  
  	spin_lock(&d->tcf_lock);
  	d->tcf_tm.lastuse = jiffies;
  	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_%d
  ",
  	       (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  	spin_unlock(&d->tcf_lock);
  	return d->tcf_action;
  }
  
  static int tcf_simp_release(struct tcf_defact *d, int bind)
  {
  	int ret = 0;
  	if (d) {
  		if (bind)
  			d->tcf_bindcnt--;
  		d->tcf_refcnt--;
  		if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  			kfree(d->tcfd_defdata);
  			tcf_hash_destroy(&d->common, &simp_hash_info);
  			ret = 1;
  		}
  	}
  	return ret;
  }
  
  static int alloc_defdata(struct tcf_defact *d, char *defdata)
  {
  	d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  	if (unlikely(!d->tcfd_defdata))
  		return -ENOMEM;
  	strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  	return 0;
  }
  
  static void reset_policy(struct tcf_defact *d, char *defdata,
  			 struct tc_defact *p)
  {
  	spin_lock_bh(&d->tcf_lock);
  	d->tcf_action = p->action;
  	memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  	strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  	spin_unlock_bh(&d->tcf_lock);
  }
  
  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)
  {
  	struct nlattr *tb[TCA_DEF_MAX + 1];
  	struct tc_defact *parm;
  	struct tcf_defact *d;
  	struct tcf_common *pc;
  	char *defdata;
  	int ret = 0, err;
  
  	if (nla == NULL)
  		return -EINVAL;
  
  	err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
  	if (err < 0)
  		return err;
  
  	if (tb[TCA_DEF_PARMS] == NULL)
  		return -EINVAL;
  
  	if (tb[TCA_DEF_DATA] == NULL)
  		return -EINVAL;
  
  	parm = nla_data(tb[TCA_DEF_PARMS]);
  	defdata = nla_data(tb[TCA_DEF_DATA]);
  
  	pc = tcf_hash_check(parm->index, a, bind);
  	if (!pc) {
  		pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind);
  		if (IS_ERR(pc))
  			return PTR_ERR(pc);
  
  		d = to_defact(pc);
  		ret = alloc_defdata(d, defdata);
  		if (ret < 0) {
  			if (est)
  				gen_kill_estimator(&pc->tcfc_bstats,
  						   &pc->tcfc_rate_est);
  			kfree_rcu(pc, tcfc_rcu);
  			return ret;
  		}
  		d->tcf_action = parm->action;
  		ret = ACT_P_CREATED;
  	} else {
  		d = to_defact(pc);
  
  		if (bind)
  			return 0;
  		tcf_simp_release(d, bind);
  		if (!ovr)
  			return -EEXIST;
  
  		reset_policy(d, defdata, parm);
  	}
  
  	if (ret == ACT_P_CREATED)
  		tcf_hash_insert(pc, a->ops->hinfo);
  	return ret;
  }
  
  static int tcf_simp_cleanup(struct tc_action *a, int bind)
  {
  	struct tcf_defact *d = a->priv;
  
  	if (d)
  		return tcf_simp_release(d, bind);
  	return 0;
  }
  
  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 = a->priv;
  	struct tc_defact opt = {
  		.index   = d->tcf_index,
  		.refcnt  = d->tcf_refcnt - ref,
  		.bindcnt = d->tcf_bindcnt - bind,
  		.action  = d->tcf_action,
  	};
  	struct tcf_t t;
  
  	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
  	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
  		goto nla_put_failure;
  	t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
  	t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
  	t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
  	if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
  		goto nla_put_failure;
  	return skb->len;
  
  nla_put_failure:
  	nlmsg_trim(skb, b);
  	return -1;
  }
  
  static struct tc_action_ops act_simp_ops = {
  	.kind		=	"simple",
  	.hinfo		=	&simp_hash_info,
  	.type		=	TCA_ACT_SIMP,
  	.owner		=	THIS_MODULE,
  	.act		=	tcf_simp,
  	.dump		=	tcf_simp_dump,
  	.cleanup	=	tcf_simp_cleanup,
  	.init		=	tcf_simp_init,
  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2005)");
  MODULE_DESCRIPTION("Simple example action");
  MODULE_LICENSE("GPL");
  
  static int __init simp_init_module(void)
  {
  	int err, ret;
  	err = tcf_hashinfo_init(&simp_hash_info, SIMP_TAB_MASK);
  	if (err)
  		return err;
  
  	ret = tcf_register_action(&act_simp_ops);
  	if (!ret)
  		pr_info("Simple TC action Loaded
  ");
  	else
  		tcf_hashinfo_destroy(&simp_hash_info);
  
  	return ret;
  }
  
  static void __exit simp_cleanup_module(void)
  {
  	tcf_hashinfo_destroy(&simp_hash_info);
  	tcf_unregister_action(&act_simp_ops);
  }
  
  module_init(simp_init_module);
  module_exit(simp_cleanup_module);