net/sched/cls_tcindex.c - linux - Git at Google

 /*
  * net/sched/cls_tcindex.c	Packet classifier for skb->tc_index
  *
  * Written 1998,1999 by Werner Almesberger, EPFL ICA
  */

 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <net/act_api.h>
 #include <net/netlink.h>
 #include <net/pkt_cls.h>

 /*
  * Passing parameters to the root seems to be done more awkwardly than really
  * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
  * verified. FIXME.
  */

 #define PERFECT_HASH_THRESHOLD	64	/* use perfect hash if not bigger */
 #define DEFAULT_HASH_SIZE	64	/* optimized for diffserv */


 struct tcindex_filter_result {
 	struct tcf_exts		exts;
 	struct tcf_result	res;
 };

 struct tcindex_filter {
 	u16 key;
 	struct tcindex_filter_result result;
 	struct tcindex_filter *next;
 };


 struct tcindex_data {
 	struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
 	struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
 				      NULL if unused */
 	u16 mask;		/* AND key with mask */
 	int shift;		/* shift ANDed key to the right */
 	int hash;		/* hash table size; 0 if undefined */
 	int alloc_hash;		/* allocated size */
 	int fall_through;	/* 0: only classify if explicit match */
 };

 static inline int
 tcindex_filter_is_set(struct tcindex_filter_result *r)
 {
 	return tcf_exts_is_predicative(&r->exts) || r->res.classid;
 }

 static struct tcindex_filter_result *
 tcindex_lookup(struct tcindex_data *p, u16 key)
 {
 	struct tcindex_filter *f;

 	if (p->perfect)
 		return tcindex_filter_is_set(p->perfect + key) ?
 			p->perfect + key : NULL;
 	else if (p->h) {
 		for (f = p->h[key % p->hash]; f; f = f->next)
 			if (f->key == key)
 				return &f->result;
 	}

 	return NULL;
 }


 static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 			    struct tcf_result *res)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter_result *f;
 	int key = (skb->tc_index & p->mask) >> p->shift;

 	pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
 		 skb, tp, res, p);

 	f = tcindex_lookup(p, key);
 	if (!f) {
 		if (!p->fall_through)
 			return -1;
 		res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
 		res->class = 0;
 		pr_debug("alg 0x%x\n", res->classid);
 		return 0;
 	}
 	*res = f->res;
 	pr_debug("map 0x%x\n", res->classid);

 	return tcf_exts_exec(skb, &f->exts, res);
 }


 static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter_result *r;

 	pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
 	if (p->perfect && handle >= p->alloc_hash)
 		return 0;
 	r = tcindex_lookup(p, handle);
 	return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
 }


 static void tcindex_put(struct tcf_proto *tp, unsigned long f)
 {
 	pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
 }


 static int tcindex_init(struct tcf_proto *tp)
 {
 	struct tcindex_data *p;

 	pr_debug("tcindex_init(tp %p)\n", tp);
 	p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
 	if (!p)
 		return -ENOMEM;

 	p->mask = 0xffff;
 	p->hash = DEFAULT_HASH_SIZE;
 	p->fall_through = 1;

 	tp->root = p;
 	return 0;
 }


 static int
 __tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
 	struct tcindex_filter *f = NULL;

 	pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
 	if (p->perfect) {
 		if (!r->res.class)
 			return -ENOENT;
 	} else {
 		int i;
 		struct tcindex_filter **walk = NULL;

 		for (i = 0; i < p->hash; i++)
 			for (walk = p->h+i; *walk; walk = &(*walk)->next)
 				if (&(*walk)->result == r)
 					goto found;
 		return -ENOENT;

 found:
 		f = *walk;
 		if (lock)
 			tcf_tree_lock(tp);
 		*walk = f->next;
 		if (lock)
 			tcf_tree_unlock(tp);
 	}
 	tcf_unbind_filter(tp, &r->res);
 	tcf_exts_destroy(tp, &r->exts);
 	kfree(f);
 	return 0;
 }

 static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 {
 	return __tcindex_delete(tp, arg, 1);
 }

 static inline int
 valid_perfect_hash(struct tcindex_data *p)
 {
 	return  p->hash > (p->mask >> p->shift);
 }

 static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
 	[TCA_TCINDEX_HASH]		= { .type = NLA_U32 },
 	[TCA_TCINDEX_MASK]		= { .type = NLA_U16 },
 	[TCA_TCINDEX_SHIFT]		= { .type = NLA_U32 },
 	[TCA_TCINDEX_FALL_THROUGH]	= { .type = NLA_U32 },
 	[TCA_TCINDEX_CLASSID]		= { .type = NLA_U32 },
 };

 static void tcindex_filter_result_init(struct tcindex_filter_result *r)
 {
 	memset(r, 0, sizeof(*r));
 	tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
 }

 static int
 tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		  u32 handle, struct tcindex_data *p,
 		  struct tcindex_filter_result *r, struct nlattr **tb,
 		  struct nlattr *est, bool ovr)
 {
 	int err, balloc = 0;
 	struct tcindex_filter_result new_filter_result, *old_r = r;
 	struct tcindex_filter_result cr;
 	struct tcindex_data cp;
 	struct tcindex_filter *f = NULL; /* make gcc behave */
 	struct tcf_exts e;

 	tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
 	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
 	if (err < 0)
 		return err;

 	memcpy(&cp, p, sizeof(cp));
 	tcindex_filter_result_init(&new_filter_result);

 	tcindex_filter_result_init(&cr);
 	if (old_r)
 		cr.res = r->res;

 	if (tb[TCA_TCINDEX_HASH])
 		cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);

 	if (tb[TCA_TCINDEX_MASK])
 		cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);

 	if (tb[TCA_TCINDEX_SHIFT])
 		cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);

 	err = -EBUSY;
 	/* Hash already allocated, make sure that we still meet the
 	 * requirements for the allocated hash.
 	 */
 	if (cp.perfect) {
 		if (!valid_perfect_hash(&cp) ||
 		    cp.hash > cp.alloc_hash)
 			goto errout;
 	} else if (cp.h && cp.hash != cp.alloc_hash)
 		goto errout;

 	err = -EINVAL;
 	if (tb[TCA_TCINDEX_FALL_THROUGH])
 		cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);

 	if (!cp.hash) {
 		/* Hash not specified, use perfect hash if the upper limit
 		 * of the hashing index is below the threshold.
 		 */
 		if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
 			cp.hash = (cp.mask >> cp.shift) + 1;
 		else
 			cp.hash = DEFAULT_HASH_SIZE;
 	}

 	if (!cp.perfect && !cp.h)
 		cp.alloc_hash = cp.hash;

 	/* Note: this could be as restrictive as if (handle & ~(mask >> shift))
 	 * but then, we'd fail handles that may become valid after some future
 	 * mask change. While this is extremely unlikely to ever matter,
 	 * the check below is safer (and also more backwards-compatible).
 	 */
 	if (cp.perfect || valid_perfect_hash(&cp))
 		if (handle >= cp.alloc_hash)
 			goto errout;


 	err = -ENOMEM;
 	if (!cp.perfect && !cp.h) {
 		if (valid_perfect_hash(&cp)) {
 			int i;

 			cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
 			if (!cp.perfect)
 				goto errout;
 			for (i = 0; i < cp.hash; i++)
 				tcf_exts_init(&cp.perfect[i].exts, TCA_TCINDEX_ACT,
 					      TCA_TCINDEX_POLICE);
 			balloc = 1;
 		} else {
 			cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
 			if (!cp.h)
 				goto errout;
 			balloc = 2;
 		}
 	}

 	if (cp.perfect)
 		r = cp.perfect + handle;
 	else
 		r = tcindex_lookup(&cp, handle) ? : &new_filter_result;

 	if (r == &new_filter_result) {
 		f = kzalloc(sizeof(*f), GFP_KERNEL);
 		if (!f)
 			goto errout_alloc;
 	}

 	if (tb[TCA_TCINDEX_CLASSID]) {
 		cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
 		tcf_bind_filter(tp, &cr.res, base);
 	}

 	if (old_r)
 		tcf_exts_change(tp, &r->exts, &e);
 	else
 		tcf_exts_change(tp, &cr.exts, &e);

 	tcf_tree_lock(tp);
 	if (old_r && old_r != r)
 		tcindex_filter_result_init(old_r);

 	memcpy(p, &cp, sizeof(cp));
 	r->res = cr.res;

 	if (r == &new_filter_result) {
 		struct tcindex_filter **fp;

 		f->key = handle;
 		f->result = new_filter_result;
 		f->next = NULL;
 		for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
 			/* nothing */;
 		*fp = f;
 	}
 	tcf_tree_unlock(tp);

 	return 0;

 errout_alloc:
 	if (balloc == 1)
 		kfree(cp.perfect);
 	else if (balloc == 2)
 		kfree(cp.h);
 errout:
 	tcf_exts_destroy(tp, &e);
 	return err;
 }

 static int
 tcindex_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 nlattr *opt = tca[TCA_OPTIONS];
 	struct nlattr *tb[TCA_TCINDEX_MAX + 1];
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
 	int err;

 	pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
 	    "p %p,r %p,*arg 0x%lx\n",
 	    tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);

 	if (!opt)
 		return 0;

 	err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
 	if (err < 0)
 		return err;

 	return tcindex_set_parms(net, tp, base, handle, p, r, tb,
 				 tca[TCA_RATE], ovr);
 }


 static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter *f, *next;
 	int i;

 	pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
 	if (p->perfect) {
 		for (i = 0; i < p->hash; i++) {
 			if (!p->perfect[i].res.class)
 				continue;
 			if (walker->count >= walker->skip) {
 				if (walker->fn(tp,
 				    (unsigned long) (p->perfect+i), walker)
 				     < 0) {
 					walker->stop = 1;
 					return;
 				}
 			}
 			walker->count++;
 		}
 	}
 	if (!p->h)
 		return;
 	for (i = 0; i < p->hash; i++) {
 		for (f = p->h[i]; f; f = next) {
 			next = f->next;
 			if (walker->count >= walker->skip) {
 				if (walker->fn(tp, (unsigned long) &f->result,
 				    walker) < 0) {
 					walker->stop = 1;
 					return;
 				}
 			}
 			walker->count++;
 		}
 	}
 }


 static int tcindex_destroy_element(struct tcf_proto *tp,
     unsigned long arg, struct tcf_walker *walker)
 {
 	return __tcindex_delete(tp, arg, 0);
 }


 static void tcindex_destroy(struct tcf_proto *tp)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcf_walker walker;

 	pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
 	walker.count = 0;
 	walker.skip = 0;
 	walker.fn = tcindex_destroy_element;
 	tcindex_walk(tp, &walker);
 	kfree(p->perfect);
 	kfree(p->h);
 	kfree(p);
 	tp->root = NULL;
 }


 static int tcindex_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
     struct sk_buff *skb, struct tcmsg *t)
 {
 	struct tcindex_data *p = tp->root;
 	struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
 	unsigned char *b = skb_tail_pointer(skb);
 	struct nlattr *nest;

 	pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
 		 tp, fh, skb, t, p, r, b);
 	pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);

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

 	if (!fh) {
 		t->tcm_handle = ~0; /* whatever ... */
 		if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) ||
 		    nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) ||
 		    nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) ||
 		    nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
 			goto nla_put_failure;
 		nla_nest_end(skb, nest);
 	} else {
 		if (p->perfect) {
 			t->tcm_handle = r-p->perfect;
 		} else {
 			struct tcindex_filter *f;
 			int i;

 			t->tcm_handle = 0;
 			for (i = 0; !t->tcm_handle && i < p->hash; i++) {
 				for (f = p->h[i]; !t->tcm_handle && f;
 				     f = f->next) {
 					if (&f->result == r)
 						t->tcm_handle = f->key;
 				}
 			}
 		}
 		pr_debug("handle = %d\n", t->tcm_handle);
 		if (r->res.class &&
 		    nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
 			goto nla_put_failure;

 		if (tcf_exts_dump(skb, &r->exts) < 0)
 			goto nla_put_failure;
 		nla_nest_end(skb, nest);

 		if (tcf_exts_dump_stats(skb, &r->exts) < 0)
 			goto nla_put_failure;
 	}

 	return skb->len;

 nla_put_failure:
 	nlmsg_trim(skb, b);
 	return -1;
 }

 static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
 	.kind		=	"tcindex",
 	.classify	=	tcindex_classify,
 	.init		=	tcindex_init,
 	.destroy	=	tcindex_destroy,
 	.get		=	tcindex_get,
 	.put		=	tcindex_put,
 	.change		=	tcindex_change,
 	.delete		=	tcindex_delete,
 	.walk		=	tcindex_walk,
 	.dump		=	tcindex_dump,
 	.owner		=	THIS_MODULE,
 };

 static int __init init_tcindex(void)
 {
 	return register_tcf_proto_ops(&cls_tcindex_ops);
 }

 static void __exit exit_tcindex(void)
 {
 	unregister_tcf_proto_ops(&cls_tcindex_ops);
 }

 module_init(init_tcindex)
 module_exit(exit_tcindex)
 MODULE_LICENSE("GPL");
	/*
	* net/sched/cls_tcindex.c Packet classifier for skb->tc_index
	*
	* Written 1998,1999 by Werner Almesberger, EPFL ICA
	*/

	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/skbuff.h>
	#include <linux/errno.h>
	#include <linux/slab.h>
	#include <net/act_api.h>
	#include <net/netlink.h>
	#include <net/pkt_cls.h>

	/*
	* Passing parameters to the root seems to be done more awkwardly than really
	* necessary. At least, u32 doesn't seem to use such dirty hacks. To be
	* verified. FIXME.
	*/

	#define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */
	#define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */


	struct tcindex_filter_result {
	struct tcf_exts exts;
	struct tcf_result res;
	};

	struct tcindex_filter {
	u16 key;
	struct tcindex_filter_result result;
	struct tcindex_filter *next;
	};


	struct tcindex_data {
	struct tcindex_filter_result perfect; / perfect hash; NULL if none */
	struct tcindex_filter *h; / imperfect hash; only used if !perfect;
	NULL if unused */
	u16 mask; /* AND key with mask */
	int shift; /* shift ANDed key to the right */
	int hash; /* hash table size; 0 if undefined */
	int alloc_hash; /* allocated size */
	int fall_through; /* 0: only classify if explicit match */
	};

	static inline int
	tcindex_filter_is_set(struct tcindex_filter_result *r)
	{
	return tcf_exts_is_predicative(&r->exts) \|\| r->res.classid;
	}

	static struct tcindex_filter_result *
	tcindex_lookup(struct tcindex_data *p, u16 key)
	{
	struct tcindex_filter *f;

	if (p->perfect)
	return tcindex_filter_is_set(p->perfect + key) ?
	p->perfect + key : NULL;
	else if (p->h) {
	for (f = p->h[key % p->hash]; f; f = f->next)
	if (f->key == key)
	return &f->result;
	}

	return NULL;
	}


	static int tcindex_classify(struct sk_buff skb, const struct tcf_proto tp,
	struct tcf_result *res)
	{
	struct tcindex_data *p = tp->root;
	struct tcindex_filter_result *f;
	int key = (skb->tc_index & p->mask) >> p->shift;

	pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
	skb, tp, res, p);

	f = tcindex_lookup(p, key);
	if (!f) {
	if (!p->fall_through)
	return -1;
	res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
	res->class = 0;
	pr_debug("alg 0x%x\n", res->classid);
	return 0;
	}
	*res = f->res;
	pr_debug("map 0x%x\n", res->classid);

	return tcf_exts_exec(skb, &f->exts, res);
	}


	static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
	{
	struct tcindex_data *p = tp->root;
	struct tcindex_filter_result *r;

	pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
	if (p->perfect && handle >= p->alloc_hash)
	return 0;
	r = tcindex_lookup(p, handle);
	return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
	}


	static void tcindex_put(struct tcf_proto *tp, unsigned long f)
	{
	pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
	}


	static int tcindex_init(struct tcf_proto *tp)
	{
	struct tcindex_data *p;

	pr_debug("tcindex_init(tp %p)\n", tp);
	p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
	if (!p)
	return -ENOMEM;

	p->mask = 0xffff;
	p->hash = DEFAULT_HASH_SIZE;
	p->fall_through = 1;

	tp->root = p;
	return 0;
	}


	static int
	__tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
	{
	struct tcindex_data *p = tp->root;
	struct tcindex_filter_result r = (struct tcindex_filter_result ) arg;
	struct tcindex_filter *f = NULL;

	pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
	if (p->perfect) {
	if (!r->res.class)
	return -ENOENT;
	} else {
	int i;
	struct tcindex_filter **walk = NULL;

	for (i = 0; i < p->hash; i++)
	for (walk = p->h+i; walk; walk = &(walk)->next)
	if (&(*walk)->result == r)
	goto found;
	return -ENOENT;

	found:
	f = *walk;
	if (lock)
	tcf_tree_lock(tp);
	*walk = f->next;
	if (lock)
	tcf_tree_unlock(tp);
	}
	tcf_unbind_filter(tp, &r->res);
	tcf_exts_destroy(tp, &r->exts);
	kfree(f);
	return 0;
	}

	static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
	{
	return __tcindex_delete(tp, arg, 1);
	}

	static inline int
	valid_perfect_hash(struct tcindex_data *p)
	{
	return p->hash > (p->mask >> p->shift);
	}

	static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
	[TCA_TCINDEX_HASH] = { .type = NLA_U32 },
	[TCA_TCINDEX_MASK] = { .type = NLA_U16 },
	[TCA_TCINDEX_SHIFT] = { .type = NLA_U32 },
	[TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 },
	[TCA_TCINDEX_CLASSID] = { .type = NLA_U32 },
	};

	static void tcindex_filter_result_init(struct tcindex_filter_result *r)
	{
	memset(r, 0, sizeof(*r));
	tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
	}

	static int
	tcindex_set_parms(struct net net, struct tcf_proto tp, unsigned long base,
	u32 handle, struct tcindex_data *p,
	struct tcindex_filter_result r, struct nlattr *tb,
	struct nlattr *est, bool ovr)
	{
	int err, balloc = 0;
	struct tcindex_filter_result new_filter_result, *old_r = r;
	struct tcindex_filter_result cr;
	struct tcindex_data cp;
	struct tcindex_filter f = NULL; / make gcc behave */
	struct tcf_exts e;

	tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
	err = tcf_exts_validate(net, tp, tb, est, &e, ovr);
	if (err < 0)
	return err;

	memcpy(&cp, p, sizeof(cp));
	tcindex_filter_result_init(&new_filter_result);

	tcindex_filter_result_init(&cr);
	if (old_r)
	cr.res = r->res;

	if (tb[TCA_TCINDEX_HASH])
	cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);

	if (tb[TCA_TCINDEX_MASK])
	cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);

	if (tb[TCA_TCINDEX_SHIFT])
	cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);

	err = -EBUSY;
	/* Hash already allocated, make sure that we still meet the
	* requirements for the allocated hash.
	*/
	if (cp.perfect) {
	if (!valid_perfect_hash(&cp) \|\|
	cp.hash > cp.alloc_hash)
	goto errout;
	} else if (cp.h && cp.hash != cp.alloc_hash)
	goto errout;

	err = -EINVAL;
	if (tb[TCA_TCINDEX_FALL_THROUGH])
	cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);

	if (!cp.hash) {
	/* Hash not specified, use perfect hash if the upper limit
	* of the hashing index is below the threshold.
	*/
	if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
	cp.hash = (cp.mask >> cp.shift) + 1;
	else
	cp.hash = DEFAULT_HASH_SIZE;
	}

	if (!cp.perfect && !cp.h)
	cp.alloc_hash = cp.hash;

	/* Note: this could be as restrictive as if (handle & ~(mask >> shift))
	* but then, we'd fail handles that may become valid after some future
	* mask change. While this is extremely unlikely to ever matter,
	* the check below is safer (and also more backwards-compatible).
	*/
	if (cp.perfect \|\| valid_perfect_hash(&cp))
	if (handle >= cp.alloc_hash)
	goto errout;


	err = -ENOMEM;
	if (!cp.perfect && !cp.h) {
	if (valid_perfect_hash(&cp)) {
	int i;

	cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
	if (!cp.perfect)
	goto errout;
	for (i = 0; i < cp.hash; i++)
	tcf_exts_init(&cp.perfect[i].exts, TCA_TCINDEX_ACT,
	TCA_TCINDEX_POLICE);
	balloc = 1;
	} else {
	cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
	if (!cp.h)
	goto errout;
	balloc = 2;
	}
	}

	if (cp.perfect)
	r = cp.perfect + handle;
	else
	r = tcindex_lookup(&cp, handle) ? : &new_filter_result;

	if (r == &new_filter_result) {
	f = kzalloc(sizeof(*f), GFP_KERNEL);
	if (!f)
	goto errout_alloc;
	}

	if (tb[TCA_TCINDEX_CLASSID]) {
	cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
	tcf_bind_filter(tp, &cr.res, base);
	}

	if (old_r)
	tcf_exts_change(tp, &r->exts, &e);
	else
	tcf_exts_change(tp, &cr.exts, &e);

	tcf_tree_lock(tp);
	if (old_r && old_r != r)
	tcindex_filter_result_init(old_r);

	memcpy(p, &cp, sizeof(cp));
	r->res = cr.res;

	if (r == &new_filter_result) {
	struct tcindex_filter **fp;

	f->key = handle;
	f->result = new_filter_result;
	f->next = NULL;
	for (fp = p->h+(handle % p->hash); fp; fp = &(fp)->next)
	/* nothing */;
	*fp = f;
	}
	tcf_tree_unlock(tp);

	return 0;

	errout_alloc:
	if (balloc == 1)
	kfree(cp.perfect);
	else if (balloc == 2)
	kfree(cp.h);
	errout:
	tcf_exts_destroy(tp, &e);
	return err;
	}

	static int
	tcindex_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 nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_TCINDEX_MAX + 1];
	struct tcindex_data *p = tp->root;
	struct tcindex_filter_result r = (struct tcindex_filter_result ) *arg;
	int err;

	pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
	"p %p,r %p,*arg 0x%lx\n",
	tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);

	if (!opt)
	return 0;

	err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
	if (err < 0)
	return err;

	return tcindex_set_parms(net, tp, base, handle, p, r, tb,
	tca[TCA_RATE], ovr);
	}


	static void tcindex_walk(struct tcf_proto tp, struct tcf_walker walker)
	{
	struct tcindex_data *p = tp->root;
	struct tcindex_filter f, next;
	int i;

	pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
	if (p->perfect) {
	for (i = 0; i < p->hash; i++) {
	if (!p->perfect[i].res.class)
	continue;
	if (walker->count >= walker->skip) {
	if (walker->fn(tp,
	(unsigned long) (p->perfect+i), walker)
	< 0) {
	walker->stop = 1;
	return;
	}
	}
	walker->count++;
	}
	}
	if (!p->h)
	return;
	for (i = 0; i < p->hash; i++) {
	for (f = p->h[i]; f; f = next) {
	next = f->next;
	if (walker->count >= walker->skip) {
	if (walker->fn(tp, (unsigned long) &f->result,
	walker) < 0) {
	walker->stop = 1;
	return;
	}
	}
	walker->count++;
	}
	}
	}


	static int tcindex_destroy_element(struct tcf_proto *tp,
	unsigned long arg, struct tcf_walker *walker)
	{
	return __tcindex_delete(tp, arg, 0);
	}


	static void tcindex_destroy(struct tcf_proto *tp)
	{
	struct tcindex_data *p = tp->root;
	struct tcf_walker walker;

	pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
	walker.count = 0;
	walker.skip = 0;
	walker.fn = tcindex_destroy_element;
	tcindex_walk(tp, &walker);
	kfree(p->perfect);
	kfree(p->h);
	kfree(p);
	tp->root = NULL;
	}


	static int tcindex_dump(struct net net, struct tcf_proto tp, unsigned long fh,
	struct sk_buff skb, struct tcmsg t)
	{
	struct tcindex_data *p = tp->root;
	struct tcindex_filter_result r = (struct tcindex_filter_result ) fh;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;

	pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
	tp, fh, skb, t, p, r, b);
	pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);

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

	if (!fh) {
	t->tcm_handle = ~0; /* whatever ... */
	if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) \|\|
	nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) \|\|
	nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) \|\|
	nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through))
	goto nla_put_failure;
	nla_nest_end(skb, nest);
	} else {
	if (p->perfect) {
	t->tcm_handle = r-p->perfect;
	} else {
	struct tcindex_filter *f;
	int i;

	t->tcm_handle = 0;
	for (i = 0; !t->tcm_handle && i < p->hash; i++) {
	for (f = p->h[i]; !t->tcm_handle && f;
	f = f->next) {
	if (&f->result == r)
	t->tcm_handle = f->key;
	}
	}
	}
	pr_debug("handle = %d\n", t->tcm_handle);
	if (r->res.class &&
	nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid))
	goto nla_put_failure;

	if (tcf_exts_dump(skb, &r->exts) < 0)
	goto nla_put_failure;
	nla_nest_end(skb, nest);

	if (tcf_exts_dump_stats(skb, &r->exts) < 0)
	goto nla_put_failure;
	}

	return skb->len;

	nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
	}

	static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
	.kind = "tcindex",
	.classify = tcindex_classify,
	.init = tcindex_init,
	.destroy = tcindex_destroy,
	.get = tcindex_get,
	.put = tcindex_put,
	.change = tcindex_change,
	.delete = tcindex_delete,
	.walk = tcindex_walk,
	.dump = tcindex_dump,
	.owner = THIS_MODULE,
	};

	static int __init init_tcindex(void)
	{
	return register_tcf_proto_ops(&cls_tcindex_ops);
	}

	static void __exit exit_tcindex(void)
	{
	unregister_tcf_proto_ops(&cls_tcindex_ops);
	}

	module_init(init_tcindex)
	module_exit(exit_tcindex)
	MODULE_LICENSE("GPL");