/*
   * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
   *
   *		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:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   *
   * Changes:
   * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
   * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
   * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
   *
   * JHS: We should remove the CONFIG_NET_CLS_IND from here
   * eventually when the meta match extension is made available
   *
   */

  #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/skbuff.h>

  #include <net/netlink.h>

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

  #define HTSIZE 256

  struct fw_head {

  	u32			mask;

  	struct fw_filter __rcu	*ht[HTSIZE];
  	struct rcu_head		rcu;

  };

  struct fw_filter {

  	struct fw_filter __rcu	*next;

  	u32			id;
  	struct tcf_result	res;
  #ifdef CONFIG_NET_CLS_IND

  	int			ifindex;

  #endif /* CONFIG_NET_CLS_IND */
  	struct tcf_exts		exts;

  	struct tcf_proto	*tp;
  	struct rcu_head		rcu;

  };

  static u32 fw_hash(u32 handle)

  {

  	handle ^= (handle >> 16);
  	handle ^= (handle >> 8);
  	return handle % HTSIZE;

  }

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

  			  struct tcf_result *res)
  {

  	struct fw_head *head = rcu_dereference_bh(tp->root);

  	struct fw_filter *f;
  	int r;

  	u32 id = skb->mark;

  
  	if (head != NULL) {

  		id &= head->mask;

  
  		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
  		     f = rcu_dereference_bh(f->next)) {

  			if (f->id == id) {
  				*res = f->res;
  #ifdef CONFIG_NET_CLS_IND

  				if (!tcf_match_indev(skb, f->ifindex))

  					continue;
  #endif /* CONFIG_NET_CLS_IND */
  				r = tcf_exts_exec(skb, &f->exts, res);
  				if (r < 0)
  					continue;
  
  				return r;
  			}
  		}
  	} else {
  		/* old method */

  		if (id && (TC_H_MAJ(id) == 0 ||
  			   !(TC_H_MAJ(id ^ tp->q->handle)))) {

  			res->classid = id;
  			res->class = 0;
  			return 0;
  		}
  	}
  
  	return -1;
  }
  
  static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f;
  
  	if (head == NULL)
  		return 0;

  	f = rtnl_dereference(head->ht[fw_hash(handle)]);
  	for (; f; f = rtnl_dereference(f->next)) {

  		if (f->id == handle)
  			return (unsigned long)f;
  	}
  	return 0;
  }

  static int fw_init(struct tcf_proto *tp)
  {
  	return 0;
  }

  static void fw_delete_filter(struct rcu_head *head)

  {

  	struct fw_filter *f = container_of(head, struct fw_filter, rcu);

  	tcf_exts_destroy(&f->exts);

  	kfree(f);
  }
  
  static void fw_destroy(struct tcf_proto *tp)
  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f;
  	int h;
  
  	if (head == NULL)
  		return;

  	for (h = 0; h < HTSIZE; h++) {

  		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
  			RCU_INIT_POINTER(head->ht[h],
  					 rtnl_dereference(f->next));

  			tcf_unbind_filter(tp, &f->res);

  			call_rcu(&f->rcu, fw_delete_filter);

  		}
  	}

  	RCU_INIT_POINTER(tp->root, NULL);
  	kfree_rcu(head, rcu);

  }
  
  static int fw_delete(struct tcf_proto *tp, unsigned long arg)
  {

  	struct fw_head *head = rtnl_dereference(tp->root);

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

  	struct fw_filter __rcu **fp;
  	struct fw_filter *pfp;

  
  	if (head == NULL || f == NULL)
  		goto out;

  	fp = &head->ht[fw_hash(f->id)];
  
  	for (pfp = rtnl_dereference(*fp); pfp;
  	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
  		if (pfp == f) {
  			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));

  			tcf_unbind_filter(tp, &f->res);

  			call_rcu(&f->rcu, fw_delete_filter);

  			return 0;
  		}
  	}
  out:
  	return -EINVAL;
  }

  static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
  	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
  	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
  	[TCA_FW_MASK]		= { .type = NLA_U32 },
  };

  static int

  fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,

  	struct nlattr **tb, struct nlattr **tca, unsigned long base, bool ovr)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct tcf_exts e;

  	u32 mask;

  	int err;

  	tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);

  	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);

  	if (err < 0)
  		return err;

  	if (tb[TCA_FW_CLASSID]) {

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

  		tcf_bind_filter(tp, &f->res, base);
  	}
  
  #ifdef CONFIG_NET_CLS_IND

  	if (tb[TCA_FW_INDEV]) {

  		int ret;
  		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);

  		if (ret < 0) {
  			err = ret;

  			goto errout;

  		}

  		f->ifindex = ret;

  	}
  #endif /* CONFIG_NET_CLS_IND */

  	err = -EINVAL;

  	if (tb[TCA_FW_MASK]) {

  		mask = nla_get_u32(tb[TCA_FW_MASK]);

  		if (mask != head->mask)
  			goto errout;
  	} else if (head->mask != 0xFFFFFFFF)
  		goto errout;

  	tcf_exts_change(tp, &f->exts, &e);
  
  	return 0;
  errout:

  	tcf_exts_destroy(&e);

  	return err;
  }

  static int fw_change(struct net *net, struct sk_buff *in_skb,

  		     struct tcf_proto *tp, unsigned long base,

  		     u32 handle,

  		     struct nlattr **tca,

  		     unsigned long *arg, bool ovr)

  {

  	struct fw_head *head = rtnl_dereference(tp->root);

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

  	struct nlattr *opt = tca[TCA_OPTIONS];
  	struct nlattr *tb[TCA_FW_MAX + 1];

  	int err;
  
  	if (!opt)
  		return handle ? -EINVAL : 0;

  	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);

  	if (err < 0)
  		return err;

  	if (f) {
  		struct fw_filter *pfp, *fnew;
  		struct fw_filter __rcu **fp;

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

  
  		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
  		if (!fnew)
  			return -ENOBUFS;
  
  		fnew->id = f->id;
  		fnew->res = f->res;
  #ifdef CONFIG_NET_CLS_IND
  		fnew->ifindex = f->ifindex;
  #endif /* CONFIG_NET_CLS_IND */
  		fnew->tp = f->tp;

  		tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);

  		err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
  		if (err < 0) {
  			kfree(fnew);
  			return err;
  		}
  
  		fp = &head->ht[fw_hash(fnew->id)];
  		for (pfp = rtnl_dereference(*fp); pfp;
  		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
  			if (pfp == f)
  				break;
  
  		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
  		rcu_assign_pointer(*fp, fnew);

  		tcf_unbind_filter(tp, &f->res);

  		call_rcu(&f->rcu, fw_delete_filter);
  
  		*arg = (unsigned long)fnew;
  		return err;

  	}
  
  	if (!handle)
  		return -EINVAL;
  
  	if (head == NULL) {

  		u32 mask = 0xFFFFFFFF;

  		if (tb[TCA_FW_MASK])

  			mask = nla_get_u32(tb[TCA_FW_MASK]);

  		head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);

  		if (head == NULL)
  			return -ENOBUFS;

  		head->mask = mask;

  		rcu_assign_pointer(tp->root, head);

  	}

  	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);

  	if (f == NULL)
  		return -ENOBUFS;

  	tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);

  	f->id = handle;

  	f->tp = tp;

  	err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);

  	if (err < 0)
  		goto errout;

  	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
  	rcu_assign_pointer(head->ht[fw_hash(handle)], f);

  
  	*arg = (unsigned long)f;
  	return 0;
  
  errout:

  	kfree(f);

  	return err;
  }
  
  static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	int h;
  
  	if (head == NULL)
  		arg->stop = 1;
  
  	if (arg->stop)
  		return;

  	for (h = 0; h < HTSIZE; h++) {

  		struct fw_filter *f;

  		for (f = rtnl_dereference(head->ht[h]); f;
  		     f = rtnl_dereference(f->next)) {

  			if (arg->count < arg->skip) {
  				arg->count++;
  				continue;
  			}
  			if (arg->fn(tp, (unsigned long)f, arg) < 0) {
  				arg->stop = 1;
  				return;
  			}
  			arg->count++;
  		}
  	}
  }

  static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,

  		   struct sk_buff *skb, struct tcmsg *t)
  {

  	struct fw_head *head = rtnl_dereference(tp->root);

  	struct fw_filter *f = (struct fw_filter *)fh;

  	struct nlattr *nest;

  
  	if (f == NULL)
  		return skb->len;
  
  	t->tcm_handle = f->id;
  
  	if (!f->res.classid && !tcf_exts_is_available(&f->exts))
  		return skb->len;

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

  	if (f->res.classid &&
  	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
  		goto nla_put_failure;

  #ifdef CONFIG_NET_CLS_IND

  	if (f->ifindex) {
  		struct net_device *dev;
  		dev = __dev_get_by_index(net, f->ifindex);
  		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
  			goto nla_put_failure;
  	}

  #endif /* CONFIG_NET_CLS_IND */

  	if (head->mask != 0xFFFFFFFF &&
  	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
  		goto nla_put_failure;

  	if (tcf_exts_dump(skb, &f->exts) < 0)

  		goto nla_put_failure;

  	nla_nest_end(skb, nest);

  	if (tcf_exts_dump_stats(skb, &f->exts) < 0)

  		goto nla_put_failure;

  
  	return skb->len;

  nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	return -1;
  }

  static struct tcf_proto_ops cls_fw_ops __read_mostly = {

  	.kind		=	"fw",
  	.classify	=	fw_classify,
  	.init		=	fw_init,
  	.destroy	=	fw_destroy,
  	.get		=	fw_get,

  	.change		=	fw_change,
  	.delete		=	fw_delete,
  	.walk		=	fw_walk,
  	.dump		=	fw_dump,
  	.owner		=	THIS_MODULE,
  };
  
  static int __init init_fw(void)
  {
  	return register_tcf_proto_ops(&cls_fw_ops);
  }

  static void __exit exit_fw(void)

  {
  	unregister_tcf_proto_ops(&cls_fw_ops);
  }
  
  module_init(init_fw)
  module_exit(exit_fw)
  MODULE_LICENSE("GPL");