text: /*
   * 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 rcu_head		rcu;
  };
  
  struct basic_filter {
  	u32			handle;
  	struct tcf_exts		exts;
  	struct tcf_ematch_tree	ematches;
  	struct tcf_result	res;
  	struct tcf_proto	*tp;
  	struct list_head	link;
  	struct rcu_head		rcu;
  };
  
  static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  			  struct tcf_result *res)
  {
  	int r;
  	struct basic_head *head = rcu_dereference_bh(tp->root);
  	struct basic_filter *f;
  
  	list_for_each_entry_rcu(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 = rtnl_dereference(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;
  			break;
  		}
  	}
  
  	return l;
  }
  
  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);
  	rcu_assign_pointer(tp->root, head);
  	return 0;
  }
  
  static void basic_delete_filter(struct rcu_head *head)
  {
  	struct basic_filter *f = container_of(head, struct basic_filter, rcu);
  
  	tcf_exts_destroy(&f->exts);
  	tcf_em_tree_destroy(&f->ematches);
  	kfree(f);
  }
  
  static void basic_destroy(struct tcf_proto *tp)
  {
  	struct basic_head *head = rtnl_dereference(tp->root);
  	struct basic_filter *f, *n;
  
  	list_for_each_entry_safe(f, n, &head->flist, link) {
  		list_del_rcu(&f->link);
  		tcf_unbind_filter(tp, &f->res);
  		call_rcu(&f->rcu, basic_delete_filter);
  	}
  	RCU_INIT_POINTER(tp->root, NULL);
  	kfree_rcu(head, rcu);
  }
  
  static int basic_delete(struct tcf_proto *tp, unsigned long arg)
  {
  	struct basic_filter *f = (struct basic_filter *) arg;
  
  	list_del_rcu(&f->link);
  	tcf_unbind_filter(tp, &f->res);
  	call_rcu(&f->rcu, basic_delete_filter);
  	return 0;
  }
  
  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 net *net, struct tcf_proto *tp,
  			   struct basic_filter *f, unsigned long base,
  			   struct nlattr **tb,
  			   struct nlattr *est, bool ovr)
  {
  	int err;
  	struct tcf_exts e;
  	struct tcf_ematch_tree t;
  
  	tcf_exts_init(&e, TCA_BASIC_ACT, TCA_BASIC_POLICE);
  	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
  	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);
  	f->tp = tp;
  
  	return 0;
  errout:
  	tcf_exts_destroy(&e);
  	return err;
  }
  
  static int basic_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)
  {
  	int err;
  	struct basic_head *head = rtnl_dereference(tp->root);
  	struct nlattr *tb[TCA_BASIC_MAX + 1];
  	struct basic_filter *fold = (struct basic_filter *) *arg;
  	struct basic_filter *fnew;
  
  	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 (fold != NULL) {
  		if (handle && fold->handle != handle)
  			return -EINVAL;
  	}
  
  	fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
  	if (!fnew)
  		return -ENOBUFS;
  
  	tcf_exts_init(&fnew->exts, TCA_BASIC_ACT, TCA_BASIC_POLICE);
  	err = -EINVAL;
  	if (handle) {
  		fnew->handle = handle;
  	} else if (fold) {
  		fnew->handle = fold->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\n");
  			goto errout;
  		}
  
  		fnew->handle = head->hgenerator;
  	}
  
  	err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr);
  	if (err < 0)
  		goto errout;
  
  	*arg = (unsigned long)fnew;
  
  	if (fold) {
  		list_replace_rcu(&fold->link, &fnew->link);
  		tcf_unbind_filter(tp, &fold->res);
  		call_rcu(&fold->rcu, basic_delete_filter);
  	} else {
  		list_add_rcu(&fnew->link, &head->flist);
  	}
  
  	return 0;
  errout:
  	kfree(fnew);
  	return err;
  }
  
  static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
  {
  	struct basic_head *head = rtnl_dereference(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 net *net, 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))
  		goto nla_put_failure;
  
  	if (tcf_exts_dump(skb, &f->exts) < 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) < 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,
  	.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");
  
  