/*
   * net/sched/cls_basic.c	Basic Packet Classifier.
   *
   *		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:	Thomas Graf <tgraf@suug.ch>
   */

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/types.h>
  #include <linux/kernel.h>

  #include <linux/string.h>

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

  #include <net/netlink.h>

  #include <net/act_api.h>
  #include <net/pkt_cls.h>

  struct basic_head {

  	u32			hgenerator;
  	struct list_head	flist;
  };

  struct basic_filter {

  	u32			handle;
  	struct tcf_exts		exts;
  	struct tcf_ematch_tree	ematches;
  	struct tcf_result	res;
  	struct list_head	link;
  };

  static const struct tcf_ext_map basic_ext_map = {

  	.action = TCA_BASIC_ACT,
  	.police = TCA_BASIC_POLICE
  };

  static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,

  			  struct tcf_result *res)
  {
  	int r;
  	struct basic_head *head = (struct basic_head *) tp->root;
  	struct basic_filter *f;
  
  	list_for_each_entry(f, &head->flist, link) {
  		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  			continue;
  		*res = f->res;
  		r = tcf_exts_exec(skb, &f->exts, res);
  		if (r < 0)
  			continue;
  		return r;
  	}
  	return -1;
  }
  
  static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  {
  	unsigned long l = 0UL;
  	struct basic_head *head = (struct basic_head *) tp->root;
  	struct basic_filter *f;
  
  	if (head == NULL)
  		return 0UL;
  
  	list_for_each_entry(f, &head->flist, link)
  		if (f->handle == handle)
  			l = (unsigned long) f;
  
  	return l;
  }
  
  static void basic_put(struct tcf_proto *tp, unsigned long f)
  {
  }
  
  static int basic_init(struct tcf_proto *tp)
  {

  	struct basic_head *head;
  
  	head = kzalloc(sizeof(*head), GFP_KERNEL);
  	if (head == NULL)
  		return -ENOBUFS;
  	INIT_LIST_HEAD(&head->flist);
  	tp->root = head;

  	return 0;
  }

  static void basic_delete_filter(struct tcf_proto *tp, struct basic_filter *f)

  {
  	tcf_unbind_filter(tp, &f->res);
  	tcf_exts_destroy(tp, &f->exts);
  	tcf_em_tree_destroy(tp, &f->ematches);
  	kfree(f);
  }
  
  static void basic_destroy(struct tcf_proto *tp)
  {

  	struct basic_head *head = tp->root;

  	struct basic_filter *f, *n;

  	list_for_each_entry_safe(f, n, &head->flist, link) {
  		list_del(&f->link);
  		basic_delete_filter(tp, f);
  	}

  	kfree(head);

  }
  
  static int basic_delete(struct tcf_proto *tp, unsigned long arg)
  {
  	struct basic_head *head = (struct basic_head *) tp->root;
  	struct basic_filter *t, *f = (struct basic_filter *) arg;
  
  	list_for_each_entry(t, &head->flist, link)
  		if (t == f) {
  			tcf_tree_lock(tp);
  			list_del(&t->link);
  			tcf_tree_unlock(tp);
  			basic_delete_filter(tp, t);
  			return 0;
  		}
  
  	return -ENOENT;
  }

  static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
  	[TCA_BASIC_CLASSID]	= { .type = NLA_U32 },
  	[TCA_BASIC_EMATCHES]	= { .type = NLA_NESTED },
  };

  static int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
  			   unsigned long base, struct nlattr **tb,
  			   struct nlattr *est)

  {
  	int err = -EINVAL;
  	struct tcf_exts e;
  	struct tcf_ematch_tree t;

  	err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
  	if (err < 0)
  		return err;

  	err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &t);

  	if (err < 0)
  		goto errout;

  	if (tb[TCA_BASIC_CLASSID]) {

  		f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);

  		tcf_bind_filter(tp, &f->res, base);
  	}
  
  	tcf_exts_change(tp, &f->exts, &e);
  	tcf_em_tree_change(tp, &f->ematches, &t);
  
  	return 0;
  errout:
  	tcf_exts_destroy(tp, &e);
  	return err;
  }
  
  static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,

  			struct nlattr **tca, unsigned long *arg)

  {

  	int err;

  	struct basic_head *head = (struct basic_head *) tp->root;

  	struct nlattr *tb[TCA_BASIC_MAX + 1];

  	struct basic_filter *f = (struct basic_filter *) *arg;

  	if (tca[TCA_OPTIONS] == NULL)

  		return -EINVAL;

  	err = nla_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
  			       basic_policy);

  	if (err < 0)
  		return err;

  
  	if (f != NULL) {
  		if (handle && f->handle != handle)
  			return -EINVAL;

  		return basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);

  	}
  
  	err = -ENOBUFS;

  	f = kzalloc(sizeof(*f), GFP_KERNEL);

  	if (f == NULL)
  		goto errout;

  
  	err = -EINVAL;
  	if (handle)
  		f->handle = handle;
  	else {

  		unsigned int i = 0x80000000;

  		do {
  			if (++head->hgenerator == 0x7FFFFFFF)
  				head->hgenerator = 1;
  		} while (--i > 0 && basic_get(tp, head->hgenerator));
  
  		if (i <= 0) {

  			pr_err("Insufficient number of handles
  ");

  			goto errout;
  		}
  
  		f->handle = head->hgenerator;
  	}

  	err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE]);

  	if (err < 0)
  		goto errout;
  
  	tcf_tree_lock(tp);
  	list_add(&f->link, &head->flist);
  	tcf_tree_unlock(tp);
  	*arg = (unsigned long) f;
  
  	return 0;
  errout:
  	if (*arg == 0UL && f)
  		kfree(f);
  
  	return err;
  }
  
  static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
  {
  	struct basic_head *head = (struct basic_head *) tp->root;
  	struct basic_filter *f;
  
  	list_for_each_entry(f, &head->flist, link) {
  		if (arg->count < arg->skip)
  			goto skip;
  
  		if (arg->fn(tp, (unsigned long) f, arg) < 0) {
  			arg->stop = 1;
  			break;
  		}
  skip:
  		arg->count++;
  	}
  }
  
  static int basic_dump(struct tcf_proto *tp, unsigned long fh,
  		      struct sk_buff *skb, struct tcmsg *t)
  {
  	struct basic_filter *f = (struct basic_filter *) fh;

  	struct nlattr *nest;

  
  	if (f == NULL)
  		return skb->len;
  
  	t->tcm_handle = f->handle;

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

  	if (f->res.classid)

  		NLA_PUT_U32(skb, TCA_BASIC_CLASSID, f->res.classid);

  	if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
  	    tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)

  		goto nla_put_failure;

  	nla_nest_end(skb, nest);

  
  	if (tcf_exts_dump_stats(skb, &f->exts, &basic_ext_map) < 0)
  		goto nla_put_failure;

  	return skb->len;

  nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	return -1;
  }

  static struct tcf_proto_ops cls_basic_ops __read_mostly = {

  	.kind		=	"basic",
  	.classify	=	basic_classify,
  	.init		=	basic_init,
  	.destroy	=	basic_destroy,
  	.get		=	basic_get,
  	.put		=	basic_put,
  	.change		=	basic_change,
  	.delete		=	basic_delete,
  	.walk		=	basic_walk,
  	.dump		=	basic_dump,
  	.owner		=	THIS_MODULE,
  };
  
  static int __init init_basic(void)
  {
  	return register_tcf_proto_ops(&cls_basic_ops);
  }

  static void __exit exit_basic(void)

  {
  	unregister_tcf_proto_ops(&cls_basic_ops);
  }
  
  module_init(init_basic)
  module_exit(exit_basic)
  MODULE_LICENSE("GPL");