/*
   * net/sched/act_api.c	Packet action API.
   *
   *		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.
   *
   * 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/act_api.h>

  #include <net/netlink.h>

  static void free_tcf(struct rcu_head *head)
  {

  	struct tc_action *p = container_of(head, struct tc_action, tcfa_rcu);

  
  	free_percpu(p->cpu_bstats);
  	free_percpu(p->cpu_qstats);
  	kfree(p);
  }

  static void tcf_hash_destroy(struct tcf_hashinfo *hinfo, struct tc_action *p)

  {

  	spin_lock_bh(&hinfo->lock);

  	hlist_del(&p->tcfa_head);

  	spin_unlock_bh(&hinfo->lock);

  	gen_kill_estimator(&p->tcfa_bstats,
  			   &p->tcfa_rate_est);

  	/*

  	 * gen_estimator est_timer() might access p->tcfa_lock

  	 * or bstats, wait a RCU grace period before freeing p
  	 */

  	call_rcu(&p->tcfa_rcu, free_tcf);

  }

  int __tcf_hash_release(struct tc_action *p, bool bind, bool strict)

  {
  	int ret = 0;
  
  	if (p) {
  		if (bind)

  			p->tcfa_bindcnt--;
  		else if (strict && p->tcfa_bindcnt > 0)

  			return -EPERM;

  		p->tcfa_refcnt--;
  		if (p->tcfa_bindcnt <= 0 && p->tcfa_refcnt <= 0) {
  			if (p->ops->cleanup)
  				p->ops->cleanup(p, bind);

  			tcf_hash_destroy(p->hinfo, p);

  			ret = ACT_P_DELETED;

  		}
  	}

  	return ret;
  }

  EXPORT_SYMBOL(__tcf_hash_release);

  static int tcf_dump_walker(struct tcf_hashinfo *hinfo, struct sk_buff *skb,

  			   struct netlink_callback *cb)

  {

  	int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;

  	struct nlattr *nest;

  	spin_lock_bh(&hinfo->lock);

  
  	s_i = cb->args[0];
  
  	for (i = 0; i < (hinfo->hmask + 1); i++) {

  		struct hlist_head *head;

  		struct tc_action *p;

  		head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];

  		hlist_for_each_entry_rcu(p, head, tcfa_head) {

  			index++;
  			if (index < s_i)
  				continue;

  			nest = nla_nest_start(skb, n_i);

  			if (nest == NULL)
  				goto nla_put_failure;

  			err = tcf_action_dump_1(skb, p, 0, 0);

  			if (err < 0) {
  				index--;

  				nlmsg_trim(skb, nest);

  				goto done;
  			}

  			nla_nest_end(skb, nest);

  			n_i++;
  			if (n_i >= TCA_ACT_MAX_PRIO)
  				goto done;
  		}
  	}
  done:

  	spin_unlock_bh(&hinfo->lock);

  	if (n_i)
  		cb->args[0] += n_i;
  	return n_i;

  nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	goto done;
  }

  static int tcf_del_walker(struct tcf_hashinfo *hinfo, struct sk_buff *skb,

  			  const struct tc_action_ops *ops)

  {

  	struct nlattr *nest;

  	int i = 0, n_i = 0;

  	int ret = -EINVAL;

  	nest = nla_nest_start(skb, 0);

  	if (nest == NULL)
  		goto nla_put_failure;

  	if (nla_put_string(skb, TCA_KIND, ops->kind))

  		goto nla_put_failure;

  	for (i = 0; i < (hinfo->hmask + 1); i++) {

  		struct hlist_head *head;
  		struct hlist_node *n;

  		struct tc_action *p;

  		head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];

  		hlist_for_each_entry_safe(p, n, head, tcfa_head) {
  			ret = __tcf_hash_release(p, false, true);

  			if (ret == ACT_P_DELETED) {

  				module_put(p->ops->owner);

  				n_i++;

  			} else if (ret < 0)
  				goto nla_put_failure;

  		}
  	}

  	if (nla_put_u32(skb, TCA_FCNT, n_i))
  		goto nla_put_failure;

  	nla_nest_end(skb, nest);

  
  	return n_i;

  nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	return ret;

  }

  int tcf_generic_walker(struct tc_action_net *tn, struct sk_buff *skb,
  		       struct netlink_callback *cb, int type,

  		       const struct tc_action_ops *ops)

  {

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	if (type == RTM_DELACTION) {

  		return tcf_del_walker(hinfo, skb, ops);

  	} else if (type == RTM_GETACTION) {

  		return tcf_dump_walker(hinfo, skb, cb);

  	} else {

  		WARN(1, "tcf_generic_walker: unknown action %d
  ", type);

  		return -EINVAL;
  	}
  }

  EXPORT_SYMBOL(tcf_generic_walker);

  static struct tc_action *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo)

  {

  	struct tc_action *p = NULL;

  	struct hlist_head *head;

  	spin_lock_bh(&hinfo->lock);
  	head = &hinfo->htab[tcf_hash(index, hinfo->hmask)];

  	hlist_for_each_entry_rcu(p, head, tcfa_head)
  		if (p->tcfa_index == index)

  			break;

  	spin_unlock_bh(&hinfo->lock);

  
  	return p;
  }

  u32 tcf_hash_new_index(struct tc_action_net *tn)

  {

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	u32 val = hinfo->index;

  
  	do {
  		if (++val == 0)
  			val = 1;
  	} while (tcf_hash_lookup(val, hinfo));

  	hinfo->index = val;

  	return val;

  }
  EXPORT_SYMBOL(tcf_hash_new_index);

  int tcf_hash_search(struct tc_action_net *tn, struct tc_action **a, u32 index)

  {

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	struct tc_action *p = tcf_hash_lookup(index, hinfo);

  
  	if (p) {

  		*a = p;

  		return 1;
  	}
  	return 0;
  }

  EXPORT_SYMBOL(tcf_hash_search);

  bool tcf_hash_check(struct tc_action_net *tn, u32 index, struct tc_action **a,

  		    int bind)

  {

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	struct tc_action *p = NULL;

  	if (index && (p = tcf_hash_lookup(index, hinfo)) != NULL) {

  		if (bind)

  			p->tcfa_bindcnt++;
  		p->tcfa_refcnt++;
  		*a = p;

  		return true;

  	}

  	return false;

  }
  EXPORT_SYMBOL(tcf_hash_check);

  void tcf_hash_cleanup(struct tc_action *a, struct nlattr *est)
  {

  	if (est)

  		gen_kill_estimator(&a->tcfa_bstats,
  				   &a->tcfa_rate_est);
  	call_rcu(&a->tcfa_rcu, free_tcf);

  }
  EXPORT_SYMBOL(tcf_hash_cleanup);

  int tcf_hash_create(struct tc_action_net *tn, u32 index, struct nlattr *est,

  		    struct tc_action **a, const struct tc_action_ops *ops,
  		    int bind, bool cpustats)

  {

  	struct tc_action *p = kzalloc(ops->size, GFP_KERNEL);

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	int err = -ENOMEM;

  
  	if (unlikely(!p))

  		return -ENOMEM;

  	p->tcfa_refcnt = 1;

  	if (bind)

  		p->tcfa_bindcnt = 1;

  	if (cpustats) {
  		p->cpu_bstats = netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
  		if (!p->cpu_bstats) {
  err1:
  			kfree(p);
  			return err;
  		}
  		p->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
  		if (!p->cpu_qstats) {
  err2:
  			free_percpu(p->cpu_bstats);
  			goto err1;
  		}
  	}

  	spin_lock_init(&p->tcfa_lock);
  	INIT_HLIST_NODE(&p->tcfa_head);
  	p->tcfa_index = index ? index : tcf_hash_new_index(tn);
  	p->tcfa_tm.install = jiffies;
  	p->tcfa_tm.lastuse = jiffies;
  	p->tcfa_tm.firstuse = 0;

  	if (est) {

  		err = gen_new_estimator(&p->tcfa_bstats, p->cpu_bstats,
  					&p->tcfa_rate_est,
  					&p->tcfa_lock, NULL, est);

  		if (err) {

  			free_percpu(p->cpu_qstats);
  			goto err2;

  		}
  	}

  	p->hinfo = hinfo;
  	p->ops = ops;
  	INIT_LIST_HEAD(&p->list);
  	*a = p;

  	return 0;

  }
  EXPORT_SYMBOL(tcf_hash_create);

  void tcf_hash_insert(struct tc_action_net *tn, struct tc_action *a)

  {

  	struct tcf_hashinfo *hinfo = tn->hinfo;

  	unsigned int h = tcf_hash(a->tcfa_index, hinfo->hmask);

  	spin_lock_bh(&hinfo->lock);

  	hlist_add_head(&a->tcfa_head, &hinfo->htab[h]);

  	spin_unlock_bh(&hinfo->lock);

  }
  EXPORT_SYMBOL(tcf_hash_insert);

  void tcf_hashinfo_destroy(const struct tc_action_ops *ops,
  			  struct tcf_hashinfo *hinfo)

  {

  	int i;
  
  	for (i = 0; i < hinfo->hmask + 1; i++) {

  		struct tc_action *p;

  		struct hlist_node *n;

  		hlist_for_each_entry_safe(p, n, &hinfo->htab[i], tcfa_head) {

  			int ret;

  			ret = __tcf_hash_release(p, false, true);

  			if (ret == ACT_P_DELETED)
  				module_put(ops->owner);
  			else if (ret < 0)
  				return;
  		}
  	}
  	kfree(hinfo->htab);
  }

  EXPORT_SYMBOL(tcf_hashinfo_destroy);

  static LIST_HEAD(act_base);

  static DEFINE_RWLOCK(act_mod_lock);

  int tcf_register_action(struct tc_action_ops *act,
  			struct pernet_operations *ops)

  {

  	struct tc_action_ops *a;

  	int ret;

  	if (!act->act || !act->dump || !act->init || !act->walk || !act->lookup)

  		return -EINVAL;

  	/* We have to register pernet ops before making the action ops visible,
  	 * otherwise tcf_action_init_1() could get a partially initialized
  	 * netns.
  	 */
  	ret = register_pernet_subsys(ops);
  	if (ret)
  		return ret;

  	write_lock(&act_mod_lock);

  	list_for_each_entry(a, &act_base, head) {

  		if (act->type == a->type || (strcmp(act->kind, a->kind) == 0)) {
  			write_unlock(&act_mod_lock);

  			unregister_pernet_subsys(ops);

  			return -EEXIST;
  		}
  	}

  	list_add_tail(&act->head, &act_base);

  	write_unlock(&act_mod_lock);

  	return 0;
  }

  EXPORT_SYMBOL(tcf_register_action);

  int tcf_unregister_action(struct tc_action_ops *act,
  			  struct pernet_operations *ops)

  {

  	struct tc_action_ops *a;

  	int err = -ENOENT;
  
  	write_lock(&act_mod_lock);

  	list_for_each_entry(a, &act_base, head) {
  		if (a == act) {
  			list_del(&act->head);
  			err = 0;

  			break;

  		}

  	}
  	write_unlock(&act_mod_lock);

  	if (!err)
  		unregister_pernet_subsys(ops);

  	return err;
  }

  EXPORT_SYMBOL(tcf_unregister_action);

  
  /* lookup by name */
  static struct tc_action_ops *tc_lookup_action_n(char *kind)
  {

  	struct tc_action_ops *a, *res = NULL;

  
  	if (kind) {
  		read_lock(&act_mod_lock);

  		list_for_each_entry(a, &act_base, head) {

  			if (strcmp(kind, a->kind) == 0) {

  				if (try_module_get(a->owner))
  					res = a;

  				break;
  			}
  		}
  		read_unlock(&act_mod_lock);
  	}

  	return res;

  }

  /* lookup by nlattr */
  static struct tc_action_ops *tc_lookup_action(struct nlattr *kind)

  {

  	struct tc_action_ops *a, *res = NULL;

  
  	if (kind) {
  		read_lock(&act_mod_lock);

  		list_for_each_entry(a, &act_base, head) {

  			if (nla_strcmp(kind, a->kind) == 0) {

  				if (try_module_get(a->owner))
  					res = a;

  				break;
  			}
  		}
  		read_unlock(&act_mod_lock);
  	}

  	return res;

  }

  int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
  		    int nr_actions, struct tcf_result *res)

  {

  	int ret = -1, i;

  
  	if (skb->tc_verd & TC_NCLS) {
  		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);

  		ret = TC_ACT_OK;
  		goto exec_done;
  	}

  	for (i = 0; i < nr_actions; i++) {
  		const struct tc_action *a = actions[i];

  repeat:

  		ret = a->ops->act(skb, a, res);

  		if (ret == TC_ACT_REPEAT)
  			goto repeat;	/* we need a ttl - JHS */
  		if (ret != TC_ACT_PIPE)
  			goto exec_done;

  	}
  exec_done:

  	return ret;
  }

  EXPORT_SYMBOL(tcf_action_exec);

  int tcf_action_destroy(struct list_head *actions, int bind)

  {

  	struct tc_action *a, *tmp;

  	int ret = 0;

  	list_for_each_entry_safe(a, tmp, actions, list) {

  		ret = __tcf_hash_release(a, bind, true);

  		if (ret == ACT_P_DELETED)

  			module_put(a->ops->owner);

  		else if (ret < 0)
  			return ret;

  	}

  	return ret;

  }
  
  int
  tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
  {

  	return a->ops->dump(skb, a, bind, ref);
  }
  
  int
  tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
  {
  	int err = -EINVAL;

  	unsigned char *b = skb_tail_pointer(skb);

  	struct nlattr *nest;

  	if (nla_put_string(skb, TCA_KIND, a->ops->kind))
  		goto nla_put_failure;

  	if (tcf_action_copy_stats(skb, a, 0))

  		goto nla_put_failure;

  	nest = nla_nest_start(skb, TCA_OPTIONS);
  	if (nest == NULL)
  		goto nla_put_failure;

  	err = tcf_action_dump_old(skb, a, bind, ref);
  	if (err > 0) {

  		nla_nest_end(skb, nest);

  		return err;
  	}

  nla_put_failure:

  	nlmsg_trim(skb, b);

  	return -1;
  }

  EXPORT_SYMBOL(tcf_action_dump_1);

  int tcf_action_dump(struct sk_buff *skb, struct list_head *actions,
  		    int bind, int ref)

  {
  	struct tc_action *a;
  	int err = -EINVAL;

  	struct nlattr *nest;

  	list_for_each_entry(a, actions, list) {

  		nest = nla_nest_start(skb, a->order);
  		if (nest == NULL)
  			goto nla_put_failure;

  		err = tcf_action_dump_1(skb, a, bind, ref);
  		if (err < 0)

  			goto errout;

  		nla_nest_end(skb, nest);

  	}
  
  	return 0;

  nla_put_failure:

  	err = -EINVAL;
  errout:

  	nla_nest_cancel(skb, nest);

  	return err;

  }

  struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla,
  				    struct nlattr *est, char *name, int ovr,
  				    int bind)

  {
  	struct tc_action *a;
  	struct tc_action_ops *a_o;
  	char act_name[IFNAMSIZ];

  	struct nlattr *tb[TCA_ACT_MAX + 1];

  	struct nlattr *kind;

  	int err;

  	if (name == NULL) {

  		err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
  		if (err < 0)

  			goto err_out;

  		err = -EINVAL;

  		kind = tb[TCA_ACT_KIND];

  		if (kind == NULL)
  			goto err_out;

  		if (nla_strlcpy(act_name, kind, IFNAMSIZ) >= IFNAMSIZ)

  			goto err_out;
  	} else {

  		err = -EINVAL;

  		if (strlcpy(act_name, name, IFNAMSIZ) >= IFNAMSIZ)
  			goto err_out;
  	}
  
  	a_o = tc_lookup_action_n(act_name);
  	if (a_o == NULL) {

  #ifdef CONFIG_MODULES

  		rtnl_unlock();

  		request_module("act_%s", act_name);

  		rtnl_lock();
  
  		a_o = tc_lookup_action_n(act_name);
  
  		/* We dropped the RTNL semaphore in order to
  		 * perform the module load.  So, even if we
  		 * succeeded in loading the module we have to
  		 * tell the caller to replay the request.  We
  		 * indicate this using -EAGAIN.
  		 */
  		if (a_o != NULL) {

  			err = -EAGAIN;

  			goto err_mod;
  		}
  #endif

  		err = -ENOENT;

  		goto err_out;
  	}

  	/* backward compatibility for policer */
  	if (name == NULL)

  		err = a_o->init(net, tb[TCA_ACT_OPTIONS], est, &a, ovr, bind);

  	else

  		err = a_o->init(net, nla, est, &a, ovr, bind);

  	if (err < 0)

  		goto err_mod;

  
  	/* module count goes up only when brand new policy is created

  	 * if it exists and is only bound to in a_o->init() then
  	 * ACT_P_CREATED is not returned (a zero is).
  	 */

  	if (err != ACT_P_CREATED)

  		module_put(a_o->owner);

  	return a;

  err_mod:
  	module_put(a_o->owner);
  err_out:

  	return ERR_PTR(err);

  }

  static void cleanup_a(struct list_head *actions, int ovr)
  {
  	struct tc_action *a;
  
  	if (!ovr)
  		return;
  
  	list_for_each_entry(a, actions, list)
  		a->tcfa_refcnt--;
  }

  int tcf_action_init(struct net *net, struct nlattr *nla, struct nlattr *est,
  		    char *name, int ovr, int bind, struct list_head *actions)

  {

  	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];

  	struct tc_action *act;

  	int err;

  	int i;

  	err = nla_parse_nested(tb, TCA_ACT_MAX_PRIO, nla, NULL);
  	if (err < 0)

  		return err;

  	for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {

  		act = tcf_action_init_1(net, tb[i], est, name, ovr, bind);

  		if (IS_ERR(act)) {
  			err = PTR_ERR(act);

  			goto err;

  		}

  		act->order = i;

  		if (ovr)
  			act->tcfa_refcnt++;

  		list_add_tail(&act->list, actions);

  	}

  
  	/* Remove the temp refcnt which was necessary to protect against
  	 * destroying an existing action which was being replaced
  	 */
  	cleanup_a(actions, ovr);

  	return 0;

  
  err:

  	tcf_action_destroy(actions, bind);
  	return err;

  }

  int tcf_action_copy_stats(struct sk_buff *skb, struct tc_action *p,

  			  int compat_mode)
  {
  	int err = 0;
  	struct gnet_dump d;

  	if (p == NULL)

  		goto errout;
  
  	/* compat_mode being true specifies a call that is supposed

  	 * to add additional backward compatibility statistic TLVs.

  	 */
  	if (compat_mode) {

  		if (p->type == TCA_OLD_COMPAT)

  			err = gnet_stats_start_copy_compat(skb, 0,

  							   TCA_STATS,
  							   TCA_XSTATS,

  							   &p->tcfa_lock, &d,

  							   TCA_PAD);

  		else
  			return 0;
  	} else
  		err = gnet_stats_start_copy(skb, TCA_ACT_STATS,

  					    &p->tcfa_lock, &d, TCA_ACT_PAD);

  
  	if (err < 0)
  		goto errout;

  	if (gnet_stats_copy_basic(NULL, &d, p->cpu_bstats, &p->tcfa_bstats) < 0 ||
  	    gnet_stats_copy_rate_est(&d, &p->tcfa_bstats,
  				     &p->tcfa_rate_est) < 0 ||

  	    gnet_stats_copy_queue(&d, p->cpu_qstats,

  				  &p->tcfa_qstats,
  				  p->tcfa_qstats.qlen) < 0)

  		goto errout;
  
  	if (gnet_stats_finish_copy(&d) < 0)
  		goto errout;
  
  	return 0;
  
  errout:
  	return -1;
  }

  static int tca_get_fill(struct sk_buff *skb, struct list_head *actions,
  			u32 portid, u32 seq, u16 flags, int event, int bind,
  			int ref)

  {
  	struct tcamsg *t;
  	struct nlmsghdr *nlh;

  	unsigned char *b = skb_tail_pointer(skb);

  	struct nlattr *nest;

  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*t), flags);

  	if (!nlh)
  		goto out_nlmsg_trim;
  	t = nlmsg_data(nlh);

  	t->tca_family = AF_UNSPEC;

  	t->tca__pad1 = 0;
  	t->tca__pad2 = 0;

  	nest = nla_nest_start(skb, TCA_ACT_TAB);
  	if (nest == NULL)

  		goto out_nlmsg_trim;

  	if (tcf_action_dump(skb, actions, bind, ref) < 0)

  		goto out_nlmsg_trim;

  	nla_nest_end(skb, nest);

  	nlh->nlmsg_len = skb_tail_pointer(skb) - b;

  	return skb->len;

  out_nlmsg_trim:

  	nlmsg_trim(skb, b);

  	return -1;
  }
  
  static int

  act_get_notify(struct net *net, u32 portid, struct nlmsghdr *n,

  	       struct list_head *actions, int event)

  {
  	struct sk_buff *skb;

  
  	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
  	if (!skb)
  		return -ENOBUFS;

  	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, event,
  			 0, 0) <= 0) {

  		kfree_skb(skb);
  		return -EINVAL;
  	}

  	return rtnl_unicast(skb, net, portid);

  }

  static struct tc_action *tcf_action_get_1(struct net *net, struct nlattr *nla,
  					  struct nlmsghdr *n, u32 portid)

  {

  	struct nlattr *tb[TCA_ACT_MAX + 1];

  	const struct tc_action_ops *ops;

  	struct tc_action *a;
  	int index;

  	int err;

  	err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
  	if (err < 0)

  		goto err_out;

  	err = -EINVAL;

  	if (tb[TCA_ACT_INDEX] == NULL ||
  	    nla_len(tb[TCA_ACT_INDEX]) < sizeof(index))

  		goto err_out;

  	index = nla_get_u32(tb[TCA_ACT_INDEX]);

  	err = -EINVAL;

  	ops = tc_lookup_action(tb[TCA_ACT_KIND]);
  	if (!ops) /* could happen in batch of actions */
  		goto err_out;

  	err = -ENOENT;

  	if (ops->lookup(net, &a, index) == 0)

  		goto err_mod;

  	module_put(ops->owner);

  	return a;

  err_mod:

  	module_put(ops->owner);

  err_out:
  	return ERR_PTR(err);

  }

  static int tca_action_flush(struct net *net, struct nlattr *nla,

  			    struct nlmsghdr *n, u32 portid)

  {
  	struct sk_buff *skb;
  	unsigned char *b;
  	struct nlmsghdr *nlh;
  	struct tcamsg *t;
  	struct netlink_callback dcb;

  	struct nlattr *nest;

  	struct nlattr *tb[TCA_ACT_MAX + 1];

  	const struct tc_action_ops *ops;

  	struct nlattr *kind;

  	int err = -ENOMEM;

  	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
  	if (!skb) {

  		pr_debug("tca_action_flush: failed skb alloc
  ");

  		return err;

  	}

  	b = skb_tail_pointer(skb);

  	err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
  	if (err < 0)

  		goto err_out;

  	err = -EINVAL;

  	kind = tb[TCA_ACT_KIND];

  	ops = tc_lookup_action(kind);
  	if (!ops) /*some idjot trying to flush unknown action */

  		goto err_out;

  	nlh = nlmsg_put(skb, portid, n->nlmsg_seq, RTM_DELACTION,
  			sizeof(*t), 0);

  	if (!nlh)
  		goto out_module_put;
  	t = nlmsg_data(nlh);

  	t->tca_family = AF_UNSPEC;

  	t->tca__pad1 = 0;
  	t->tca__pad2 = 0;

  	nest = nla_nest_start(skb, TCA_ACT_TAB);
  	if (nest == NULL)

  		goto out_module_put;

  	err = ops->walk(net, skb, &dcb, RTM_DELACTION, ops);

  	if (err < 0)

  		goto out_module_put;

  	if (err == 0)
  		goto noflush_out;

  	nla_nest_end(skb, nest);

  	nlh->nlmsg_len = skb_tail_pointer(skb) - b;

  	nlh->nlmsg_flags |= NLM_F_ROOT;

  	module_put(ops->owner);

  	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,

  			     n->nlmsg_flags & NLM_F_ECHO);

  	if (err > 0)
  		return 0;
  
  	return err;

  out_module_put:

  	module_put(ops->owner);

  err_out:

  noflush_out:

  	kfree_skb(skb);

  	return err;
  }
  
  static int

  tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
  	       u32 portid)
  {
  	int ret;
  	struct sk_buff *skb;
  
  	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
  	if (!skb)
  		return -ENOBUFS;
  
  	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, RTM_DELACTION,
  			 0, 1) <= 0) {
  		kfree_skb(skb);
  		return -EINVAL;
  	}
  
  	/* now do the delete */

  	ret = tcf_action_destroy(actions, 0);
  	if (ret < 0) {
  		kfree_skb(skb);
  		return ret;
  	}

  
  	ret = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
  			     n->nlmsg_flags & NLM_F_ECHO);
  	if (ret > 0)
  		return 0;
  	return ret;
  }
  
  static int

  tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,

  	      u32 portid, int event)

  {

  	int i, ret;

  	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];

  	struct tc_action *act;
  	LIST_HEAD(actions);

  	ret = nla_parse_nested(tb, TCA_ACT_MAX_PRIO, nla, NULL);
  	if (ret < 0)
  		return ret;

  	if (event == RTM_DELACTION && n->nlmsg_flags & NLM_F_ROOT) {

  		if (tb[1] != NULL)

  			return tca_action_flush(net, tb[1], n, portid);

  		else
  			return -EINVAL;

  	}

  	for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {

  		act = tcf_action_get_1(net, tb[i], n, portid);

  		if (IS_ERR(act)) {
  			ret = PTR_ERR(act);

  			goto err;

  		}

  		act->order = i;

  		list_add_tail(&act->list, &actions);

  	}
  
  	if (event == RTM_GETACTION)

  		ret = act_get_notify(net, portid, n, &actions, event);

  	else { /* delete */

  		ret = tcf_del_notify(net, n, &actions, portid);
  		if (ret)

  			goto err;

  		return ret;
  	}
  err:

  	if (event != RTM_GETACTION)
  		tcf_action_destroy(&actions, 0);

  	return ret;
  }

  static int
  tcf_add_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
  	       u32 portid)

  {

  	struct sk_buff *skb;

  	int err = 0;
  
  	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
  	if (!skb)
  		return -ENOBUFS;

  	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, n->nlmsg_flags,
  			 RTM_NEWACTION, 0, 0) <= 0) {
  		kfree_skb(skb);
  		return -EINVAL;
  	}

  	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
  			     n->nlmsg_flags & NLM_F_ECHO);

  	if (err > 0)
  		err = 0;
  	return err;

  }

  static int tcf_action_add(struct net *net, struct nlattr *nla,
  			  struct nlmsghdr *n, u32 portid, int ovr)

  {
  	int ret = 0;

  	LIST_HEAD(actions);

  	ret = tcf_action_init(net, nla, NULL, NULL, ovr, 0, &actions);
  	if (ret)

  		return ret;

  	return tcf_add_notify(net, n, &actions, portid);

  }

  static int tc_ctl_action(struct sk_buff *skb, struct nlmsghdr *n)

  {

  	struct net *net = sock_net(skb->sk);

  	struct nlattr *tca[TCA_ACT_MAX + 1];

  	u32 portid = skb ? NETLINK_CB(skb).portid : 0;

  	int ret = 0, ovr = 0;

  	if ((n->nlmsg_type != RTM_GETACTION) &&
  	    !netlink_capable(skb, CAP_NET_ADMIN))

  		return -EPERM;

  	ret = nlmsg_parse(n, sizeof(struct tcamsg), tca, TCA_ACT_MAX, NULL);
  	if (ret < 0)
  		return ret;
  
  	if (tca[TCA_ACT_TAB] == NULL) {

  		pr_notice("tc_ctl_action: received NO action attribs
  ");

  		return -EINVAL;
  	}

  	/* n->nlmsg_flags & NLM_F_CREATE */

  	switch (n->nlmsg_type) {
  	case RTM_NEWACTION:
  		/* we are going to assume all other flags

  		 * imply create only if it doesn't exist

  		 * Note that CREATE | EXCL implies that
  		 * but since we want avoid ambiguity (eg when flags
  		 * is zero) then just set this
  		 */

  		if (n->nlmsg_flags & NLM_F_REPLACE)

  			ovr = 1;
  replay:

  		ret = tcf_action_add(net, tca[TCA_ACT_TAB], n, portid, ovr);

  		if (ret == -EAGAIN)
  			goto replay;
  		break;
  	case RTM_DELACTION:

  		ret = tca_action_gd(net, tca[TCA_ACT_TAB], n,

  				    portid, RTM_DELACTION);

  		break;
  	case RTM_GETACTION:

  		ret = tca_action_gd(net, tca[TCA_ACT_TAB], n,

  				    portid, RTM_GETACTION);

  		break;
  	default:
  		BUG();
  	}
  
  	return ret;
  }

  static struct nlattr *find_dump_kind(const struct nlmsghdr *n)

  {

  	struct nlattr *tb1, *tb2[TCA_ACT_MAX + 1];

  	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
  	struct nlattr *nla[TCAA_MAX + 1];
  	struct nlattr *kind;

  	if (nlmsg_parse(n, sizeof(struct tcamsg), nla, TCAA_MAX, NULL) < 0)

  		return NULL;

  	tb1 = nla[TCA_ACT_TAB];

  	if (tb1 == NULL)
  		return NULL;

  	if (nla_parse(tb, TCA_ACT_MAX_PRIO, nla_data(tb1),
  		      NLMSG_ALIGN(nla_len(tb1)), NULL) < 0)

  		return NULL;

  	if (tb[1] == NULL)
  		return NULL;

  	if (nla_parse_nested(tb2, TCA_ACT_MAX, tb[1], NULL) < 0)

  		return NULL;

  	kind = tb2[TCA_ACT_KIND];

  	return kind;

  }

  static int tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)

  {

  	struct net *net = sock_net(skb->sk);

  	struct nlmsghdr *nlh;

  	unsigned char *b = skb_tail_pointer(skb);

  	struct nlattr *nest;

  	struct tc_action_ops *a_o;

  	int ret = 0;

  	struct tcamsg *t = (struct tcamsg *) nlmsg_data(cb->nlh);

  	struct nlattr *kind = find_dump_kind(cb->nlh);

  
  	if (kind == NULL) {

  		pr_info("tc_dump_action: action bad kind
  ");

  		return 0;
  	}

  	a_o = tc_lookup_action(kind);

  	if (a_o == NULL)

  		return 0;

  	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,

  			cb->nlh->nlmsg_type, sizeof(*t), 0);
  	if (!nlh)
  		goto out_module_put;
  	t = nlmsg_data(nlh);

  	t->tca_family = AF_UNSPEC;

  	t->tca__pad1 = 0;
  	t->tca__pad2 = 0;

  	nest = nla_nest_start(skb, TCA_ACT_TAB);
  	if (nest == NULL)

  		goto out_module_put;

  	ret = a_o->walk(net, skb, cb, RTM_GETACTION, a_o);

  	if (ret < 0)

  		goto out_module_put;

  
  	if (ret > 0) {

  		nla_nest_end(skb, nest);

  		ret = skb->len;
  	} else

  		nlmsg_trim(skb, b);

  	nlh->nlmsg_len = skb_tail_pointer(skb) - b;

  	if (NETLINK_CB(cb->skb).portid && ret)

  		nlh->nlmsg_flags |= NLM_F_MULTI;
  	module_put(a_o->owner);
  	return skb->len;

  out_module_put:

  	module_put(a_o->owner);

  	nlmsg_trim(skb, b);

  	return skb->len;
  }
  
  static int __init tc_action_init(void)
  {

  	rtnl_register(PF_UNSPEC, RTM_NEWACTION, tc_ctl_action, NULL, NULL);
  	rtnl_register(PF_UNSPEC, RTM_DELACTION, tc_ctl_action, NULL, NULL);
  	rtnl_register(PF_UNSPEC, RTM_GETACTION, tc_ctl_action, tc_dump_action,
  		      NULL);

  	return 0;
  }
  
  subsys_initcall(tc_action_init);