text: #ifndef __NET_PKT_CLS_H
  #define __NET_PKT_CLS_H
  
  #include <linux/pkt_cls.h>
  #include <net/sch_generic.h>
  #include <net/act_api.h>
  
  /* Basic packet classifier frontend definitions. */
  
  struct tcf_walker
  {
  	int	stop;
  	int	skip;
  	int	count;
  	int	(*fn)(struct tcf_proto *, unsigned long node, struct tcf_walker *);
  };
  
  extern int register_tcf_proto_ops(struct tcf_proto_ops *ops);
  extern int unregister_tcf_proto_ops(struct tcf_proto_ops *ops);
  
  static inline unsigned long
  __cls_set_class(unsigned long *clp, unsigned long cl)
  {
  	unsigned long old_cl;
   
  	old_cl = *clp;
  	*clp = cl;
  	return old_cl;
  }
  
  static inline unsigned long
  cls_set_class(struct tcf_proto *tp, unsigned long *clp, 
  	unsigned long cl)
  {
  	unsigned long old_cl;
  	
  	tcf_tree_lock(tp);
  	old_cl = __cls_set_class(clp, cl);
  	tcf_tree_unlock(tp);
   
  	return old_cl;
  }
  
  static inline void
  tcf_bind_filter(struct tcf_proto *tp, struct tcf_result *r, unsigned long base)
  {
  	unsigned long cl;
  
  	cl = tp->q->ops->cl_ops->bind_tcf(tp->q, base, r->classid);
  	cl = cls_set_class(tp, &r->class, cl);
  	if (cl)
  		tp->q->ops->cl_ops->unbind_tcf(tp->q, cl);
  }
  
  static inline void
  tcf_unbind_filter(struct tcf_proto *tp, struct tcf_result *r)
  {
  	unsigned long cl;
  
  	if ((cl = __cls_set_class(&r->class, 0)) != 0)
  		tp->q->ops->cl_ops->unbind_tcf(tp->q, cl);
  }
  
  struct tcf_exts
  {
  #ifdef CONFIG_NET_CLS_ACT
  	struct tc_action *action;
  #endif
  };
  
  /* Map to export classifier specific extension TLV types to the
   * generic extensions API. Unsupported extensions must be set to 0.
   */
  struct tcf_ext_map
  {
  	int action;
  	int police;
  };
  
  /**
   * tcf_exts_is_predicative - check if a predicative extension is present
   * @exts: tc filter extensions handle
   *
   * Returns 1 if a predicative extension is present, i.e. an extension which
   * might cause further actions and thus overrule the regular tcf_result.
   */
  static inline int
  tcf_exts_is_predicative(struct tcf_exts *exts)
  {
  #ifdef CONFIG_NET_CLS_ACT
  	return !!exts->action;
  #else
  	return 0;
  #endif
  }
  
  /**
   * tcf_exts_is_available - check if at least one extension is present
   * @exts: tc filter extensions handle
   *
   * Returns 1 if at least one extension is present.
   */
  static inline int
  tcf_exts_is_available(struct tcf_exts *exts)
  {
  	/* All non-predicative extensions must be added here. */
  	return tcf_exts_is_predicative(exts);
  }
  
  /**
   * tcf_exts_exec - execute tc filter extensions
   * @skb: socket buffer
   * @exts: tc filter extensions handle
   * @res: desired result
   *
   * Executes all configured extensions. Returns 0 on a normal execution,
   * a negative number if the filter must be considered unmatched or
   * a positive action code (TC_ACT_*) which must be returned to the
   * underlying layer.
   */
  static inline int
  tcf_exts_exec(struct sk_buff *skb, struct tcf_exts *exts,
  	       struct tcf_result *res)
  {
  #ifdef CONFIG_NET_CLS_ACT
  	if (exts->action)
  		return tcf_action_exec(skb, exts->action, res);
  #endif
  	return 0;
  }
  
  extern int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
  	                     struct nlattr *rate_tlv, struct tcf_exts *exts,
  	                     const struct tcf_ext_map *map);
  extern void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts);
  extern void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
  	                     struct tcf_exts *src);
  extern int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
  	                 const struct tcf_ext_map *map);
  extern int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
  	                       const struct tcf_ext_map *map);
  
  /**
   * struct tcf_pkt_info - packet information
   */
  struct tcf_pkt_info
  {
  	unsigned char *		ptr;
  	int			nexthdr;
  };
  
  #ifdef CONFIG_NET_EMATCH
  
  struct tcf_ematch_ops;
  
  /**
   * struct tcf_ematch - extended match (ematch)
   * 
   * @matchid: identifier to allow userspace to reidentify a match
   * @flags: flags specifying attributes and the relation to other matches
   * @ops: the operations lookup table of the corresponding ematch module
   * @datalen: length of the ematch specific configuration data
   * @data: ematch specific data
   */
  struct tcf_ematch
  {
  	struct tcf_ematch_ops * ops;
  	unsigned long		data;
  	unsigned int		datalen;
  	u16			matchid;
  	u16			flags;
  };
  
  static inline int tcf_em_is_container(struct tcf_ematch *em)
  {
  	return !em->ops;
  }
  
  static inline int tcf_em_is_simple(struct tcf_ematch *em)
  {
  	return em->flags & TCF_EM_SIMPLE;
  }
  
  static inline int tcf_em_is_inverted(struct tcf_ematch *em)
  {
  	return em->flags & TCF_EM_INVERT;
  }
  
  static inline int tcf_em_last_match(struct tcf_ematch *em)
  {
  	return (em->flags & TCF_EM_REL_MASK) == TCF_EM_REL_END;
  }
  
  static inline int tcf_em_early_end(struct tcf_ematch *em, int result)
  {
  	if (tcf_em_last_match(em))
  		return 1;
  
  	if (result == 0 && em->flags & TCF_EM_REL_AND)
  		return 1;
  
  	if (result != 0 && em->flags & TCF_EM_REL_OR)
  		return 1;
  
  	return 0;
  }
  	
  /**
   * struct tcf_ematch_tree - ematch tree handle
   *
   * @hdr: ematch tree header supplied by userspace
   * @matches: array of ematches
   */
  struct tcf_ematch_tree
  {
  	struct tcf_ematch_tree_hdr hdr;
  	struct tcf_ematch *	matches;
  	
  };
  
  /**
   * struct tcf_ematch_ops - ematch module operations
   * 
   * @kind: identifier (kind) of this ematch module
   * @datalen: length of expected configuration data (optional)
   * @change: called during validation (optional)
   * @match: called during ematch tree evaluation, must return 1/0
   * @destroy: called during destroyage (optional)
   * @dump: called during dumping process (optional)
   * @owner: owner, must be set to THIS_MODULE
   * @link: link to previous/next ematch module (internal use)
   */
  struct tcf_ematch_ops
  {
  	int			kind;
  	int			datalen;
  	int			(*change)(struct tcf_proto *, void *,
  					  int, struct tcf_ematch *);
  	int			(*match)(struct sk_buff *, struct tcf_ematch *,
  					 struct tcf_pkt_info *);
  	void			(*destroy)(struct tcf_proto *,
  					   struct tcf_ematch *);
  	int			(*dump)(struct sk_buff *, struct tcf_ematch *);
  	struct module		*owner;
  	struct list_head	link;
  };
  
  extern int tcf_em_register(struct tcf_ematch_ops *);
  extern void tcf_em_unregister(struct tcf_ematch_ops *);
  extern int tcf_em_tree_validate(struct tcf_proto *, struct nlattr *,
  				struct tcf_ematch_tree *);
  extern void tcf_em_tree_destroy(struct tcf_proto *, struct tcf_ematch_tree *);
  extern int tcf_em_tree_dump(struct sk_buff *, struct tcf_ematch_tree *, int);
  extern int __tcf_em_tree_match(struct sk_buff *, struct tcf_ematch_tree *,
  			       struct tcf_pkt_info *);
  
  /**
   * tcf_em_tree_change - replace ematch tree of a running classifier
   *
   * @tp: classifier kind handle
   * @dst: destination ematch tree variable
   * @src: source ematch tree (temporary tree from tcf_em_tree_validate)
   *
   * This functions replaces the ematch tree in @dst with the ematch
   * tree in @src. The classifier in charge of the ematch tree may be
   * running.
   */
  static inline void tcf_em_tree_change(struct tcf_proto *tp,
  				      struct tcf_ematch_tree *dst,
  				      struct tcf_ematch_tree *src)
  {
  	tcf_tree_lock(tp);
  	memcpy(dst, src, sizeof(*dst));
  	tcf_tree_unlock(tp);
  }
  
  /**
   * tcf_em_tree_match - evaulate an ematch tree
   *
   * @skb: socket buffer of the packet in question
   * @tree: ematch tree to be used for evaluation
   * @info: packet information examined by classifier
   *
   * This function matches @skb against the ematch tree in @tree by going
   * through all ematches respecting their logic relations returning
   * as soon as the result is obvious.
   *
   * Returns 1 if the ematch tree as-one matches, no ematches are configured
   * or ematch is not enabled in the kernel, otherwise 0 is returned.
   */
  static inline int tcf_em_tree_match(struct sk_buff *skb,
  				    struct tcf_ematch_tree *tree,
  				    struct tcf_pkt_info *info)
  {
  	if (tree->hdr.nmatches)
  		return __tcf_em_tree_match(skb, tree, info);
  	else
  		return 1;
  }
  
  #define MODULE_ALIAS_TCF_EMATCH(kind)	MODULE_ALIAS("ematch-kind-" __stringify(kind))
  
  #else /* CONFIG_NET_EMATCH */
  
  struct tcf_ematch_tree
  {
  };
  
  #define tcf_em_tree_validate(tp, tb, t) ((void)(t), 0)
  #define tcf_em_tree_destroy(tp, t) do { (void)(t); } while(0)
  #define tcf_em_tree_dump(skb, t, tlv) (0)
  #define tcf_em_tree_change(tp, dst, src) do { } while(0)
  #define tcf_em_tree_match(skb, t, info) ((void)(info), 1)
  
  #endif /* CONFIG_NET_EMATCH */
  
  static inline unsigned char * tcf_get_base_ptr(struct sk_buff *skb, int layer)
  {
  	switch (layer) {
  		case TCF_LAYER_LINK:
  			return skb->data;
  		case TCF_LAYER_NETWORK:
  			return skb_network_header(skb);
  		case TCF_LAYER_TRANSPORT:
  			return skb_transport_header(skb);
  	}
  
  	return NULL;
  }
  
  static inline int tcf_valid_offset(const struct sk_buff *skb,
  				   const unsigned char *ptr, const int len)
  {
  	return unlikely((ptr + len) < skb_tail_pointer(skb) && ptr > skb->head);
  }
  
  #ifdef CONFIG_NET_CLS_IND
  #include <net/net_namespace.h>
  
  static inline int
  tcf_change_indev(struct tcf_proto *tp, char *indev, struct nlattr *indev_tlv)
  {
  	if (nla_strlcpy(indev, indev_tlv, IFNAMSIZ) >= IFNAMSIZ)
  		return -EINVAL;
  	return 0;
  }
  
  static inline int
  tcf_match_indev(struct sk_buff *skb, char *indev)
  {
  	struct net_device *dev;
  
  	if (indev[0]) {
  		if  (!skb->iif)
  			return 0;
  		dev = __dev_get_by_index(dev_net(skb->dev), skb->iif);
  		if (!dev || strcmp(indev, dev->name))
  			return 0;
  	}
  
  	return 1;
  }
  #endif /* CONFIG_NET_CLS_IND */
  
  #endif
  