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

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * net/sched/cls_route.c	ROUTE4 classifier.
  *
  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  */

 #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/dst.h>
 #include <net/route.h>
 #include <net/netlink.h>
 #include <net/act_api.h>
 #include <net/pkt_cls.h>

 /*
  * 1. For now we assume that route tags < 256.
  *    It allows to use direct table lookups, instead of hash tables.
  * 2. For now we assume that "from TAG" and "fromdev DEV" statements
  *    are mutually  exclusive.
  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  */
 struct route4_fastmap {
 	struct route4_filter		*filter;
 	u32				id;
 	int				iif;
 };

 struct route4_head {
 	struct route4_fastmap		fastmap[16];
 	struct route4_bucket __rcu	*table[256 + 1];
 	struct rcu_head			rcu;
 };

 struct route4_bucket {
 	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
 	struct route4_filter __rcu	*ht[16 + 16 + 1];
 	struct rcu_head			rcu;
 };

 struct route4_filter {
 	struct route4_filter __rcu	*next;
 	u32			id;
 	int			iif;

 	struct tcf_result	res;
 	struct tcf_exts		exts;
 	u32			handle;
 	struct route4_bucket	*bkt;
 	struct tcf_proto	*tp;
 	struct rcu_work		rwork;
 };

 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))

 static inline int route4_fastmap_hash(u32 id, int iif)
 {
 	return id & 0xF;
 }

 static DEFINE_SPINLOCK(fastmap_lock);
 static void
 route4_reset_fastmap(struct route4_head *head)
 {
 	spin_lock_bh(&fastmap_lock);
 	memset(head->fastmap, 0, sizeof(head->fastmap));
 	spin_unlock_bh(&fastmap_lock);
 }

 static void
 route4_set_fastmap(struct route4_head *head, u32 id, int iif,
 		   struct route4_filter *f)
 {
 	int h = route4_fastmap_hash(id, iif);

 	/* fastmap updates must look atomic to aling id, iff, filter */
 	spin_lock_bh(&fastmap_lock);
 	head->fastmap[h].id = id;
 	head->fastmap[h].iif = iif;
 	head->fastmap[h].filter = f;
 	spin_unlock_bh(&fastmap_lock);
 }

 static inline int route4_hash_to(u32 id)
 {
 	return id & 0xFF;
 }

 static inline int route4_hash_from(u32 id)
 {
 	return (id >> 16) & 0xF;
 }

 static inline int route4_hash_iif(int iif)
 {
 	return 16 + ((iif >> 16) & 0xF);
 }

 static inline int route4_hash_wild(void)
 {
 	return 32;
 }

 #define ROUTE4_APPLY_RESULT()					\
 {								\
 	*res = f->res;						\
 	if (tcf_exts_has_actions(&f->exts)) {			\
 		int r = tcf_exts_exec(skb, &f->exts, res);	\
 		if (r < 0) {					\
 			dont_cache = 1;				\
 			continue;				\
 		}						\
 		return r;					\
 	} else if (!dont_cache)					\
 		route4_set_fastmap(head, id, iif, f);		\
 	return 0;						\
 }

 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 			   struct tcf_result *res)
 {
 	struct route4_head *head = rcu_dereference_bh(tp->root);
 	struct dst_entry *dst;
 	struct route4_bucket *b;
 	struct route4_filter *f;
 	u32 id, h;
 	int iif, dont_cache = 0;

 	dst = skb_dst(skb);
 	if (!dst)
 		goto failure;

 	id = dst->tclassid;

 	iif = inet_iif(skb);

 	h = route4_fastmap_hash(id, iif);

 	spin_lock(&fastmap_lock);
 	if (id == head->fastmap[h].id &&
 	    iif == head->fastmap[h].iif &&
 	    (f = head->fastmap[h].filter) != NULL) {
 		if (f == ROUTE4_FAILURE) {
 			spin_unlock(&fastmap_lock);
 			goto failure;
 		}

 		*res = f->res;
 		spin_unlock(&fastmap_lock);
 		return 0;
 	}
 	spin_unlock(&fastmap_lock);

 	h = route4_hash_to(id);

 restart:
 	b = rcu_dereference_bh(head->table[h]);
 	if (b) {
 		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
 		     f;
 		     f = rcu_dereference_bh(f->next))
 			if (f->id == id)
 				ROUTE4_APPLY_RESULT();

 		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
 		     f;
 		     f = rcu_dereference_bh(f->next))
 			if (f->iif == iif)
 				ROUTE4_APPLY_RESULT();

 		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
 		     f;
 		     f = rcu_dereference_bh(f->next))
 			ROUTE4_APPLY_RESULT();
 	}
 	if (h < 256) {
 		h = 256;
 		id &= ~0xFFFF;
 		goto restart;
 	}

 	if (!dont_cache)
 		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
 failure:
 	return -1;
 }

 static inline u32 to_hash(u32 id)
 {
 	u32 h = id & 0xFF;

 	if (id & 0x8000)
 		h += 256;
 	return h;
 }

 static inline u32 from_hash(u32 id)
 {
 	id &= 0xFFFF;
 	if (id == 0xFFFF)
 		return 32;
 	if (!(id & 0x8000)) {
 		if (id > 255)
 			return 256;
 		return id & 0xF;
 	}
 	return 16 + (id & 0xF);
 }

 static void *route4_get(struct tcf_proto *tp, u32 handle)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	struct route4_bucket *b;
 	struct route4_filter *f;
 	unsigned int h1, h2;

 	h1 = to_hash(handle);
 	if (h1 > 256)
 		return NULL;

 	h2 = from_hash(handle >> 16);
 	if (h2 > 32)
 		return NULL;

 	b = rtnl_dereference(head->table[h1]);
 	if (b) {
 		for (f = rtnl_dereference(b->ht[h2]);
 		     f;
 		     f = rtnl_dereference(f->next))
 			if (f->handle == handle)
 				return f;
 	}
 	return NULL;
 }

 static int route4_init(struct tcf_proto *tp)
 {
 	struct route4_head *head;

 	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 	if (head == NULL)
 		return -ENOBUFS;

 	rcu_assign_pointer(tp->root, head);
 	return 0;
 }

 static void __route4_delete_filter(struct route4_filter *f)
 {
 	tcf_exts_destroy(&f->exts);
 	tcf_exts_put_net(&f->exts);
 	kfree(f);
 }

 static void route4_delete_filter_work(struct work_struct *work)
 {
 	struct route4_filter *f = container_of(to_rcu_work(work),
 					       struct route4_filter,
 					       rwork);
 	rtnl_lock();
 	__route4_delete_filter(f);
 	rtnl_unlock();
 }

 static void route4_queue_work(struct route4_filter *f)
 {
 	tcf_queue_work(&f->rwork, route4_delete_filter_work);
 }

 static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
 			   struct netlink_ext_ack *extack)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	int h1, h2;

 	if (head == NULL)
 		return;

 	for (h1 = 0; h1 <= 256; h1++) {
 		struct route4_bucket *b;

 		b = rtnl_dereference(head->table[h1]);
 		if (b) {
 			for (h2 = 0; h2 <= 32; h2++) {
 				struct route4_filter *f;

 				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
 					struct route4_filter *next;

 					next = rtnl_dereference(f->next);
 					RCU_INIT_POINTER(b->ht[h2], next);
 					tcf_unbind_filter(tp, &f->res);
 					if (tcf_exts_get_net(&f->exts))
 						route4_queue_work(f);
 					else
 						__route4_delete_filter(f);
 				}
 			}
 			RCU_INIT_POINTER(head->table[h1], NULL);
 			kfree_rcu(b, rcu);
 		}
 	}
 	kfree_rcu(head, rcu);
 }

 static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
 			 bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	struct route4_filter *f = arg;
 	struct route4_filter __rcu **fp;
 	struct route4_filter *nf;
 	struct route4_bucket *b;
 	unsigned int h = 0;
 	int i, h1;

 	if (!head || !f)
 		return -EINVAL;

 	h = f->handle;
 	b = f->bkt;

 	fp = &b->ht[from_hash(h >> 16)];
 	for (nf = rtnl_dereference(*fp); nf;
 	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
 		if (nf == f) {
 			/* unlink it */
 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));

 			/* Remove any fastmap lookups that might ref filter
 			 * notice we unlink'd the filter so we can't get it
 			 * back in the fastmap.
 			 */
 			route4_reset_fastmap(head);

 			/* Delete it */
 			tcf_unbind_filter(tp, &f->res);
 			tcf_exts_get_net(&f->exts);
 			tcf_queue_work(&f->rwork, route4_delete_filter_work);

 			/* Strip RTNL protected tree */
 			for (i = 0; i <= 32; i++) {
 				struct route4_filter *rt;

 				rt = rtnl_dereference(b->ht[i]);
 				if (rt)
 					goto out;
 			}

 			/* OK, session has no flows */
 			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
 			kfree_rcu(b, rcu);
 			break;
 		}
 	}

 out:
 	*last = true;
 	for (h1 = 0; h1 <= 256; h1++) {
 		if (rcu_access_pointer(head->table[h1])) {
 			*last = false;
 			break;
 		}
 	}

 	return 0;
 }

 static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
 	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
 	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
 	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
 	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
 };

 static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 			    unsigned long base, struct route4_filter *f,
 			    u32 handle, struct route4_head *head,
 			    struct nlattr **tb, struct nlattr *est, int new,
 			    bool ovr, struct netlink_ext_ack *extack)
 {
 	u32 id = 0, to = 0, nhandle = 0x8000;
 	struct route4_filter *fp;
 	unsigned int h1;
 	struct route4_bucket *b;
 	int err;

 	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
 	if (err < 0)
 		return err;

 	if (tb[TCA_ROUTE4_TO]) {
 		if (new && handle & 0x8000)
 			return -EINVAL;
 		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
 		if (to > 0xFF)
 			return -EINVAL;
 		nhandle = to;
 	}

 	if (tb[TCA_ROUTE4_FROM]) {
 		if (tb[TCA_ROUTE4_IIF])
 			return -EINVAL;
 		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
 		if (id > 0xFF)
 			return -EINVAL;
 		nhandle |= id << 16;
 	} else if (tb[TCA_ROUTE4_IIF]) {
 		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
 		if (id > 0x7FFF)
 			return -EINVAL;
 		nhandle |= (id | 0x8000) << 16;
 	} else
 		nhandle |= 0xFFFF << 16;

 	if (handle && new) {
 		nhandle |= handle & 0x7F00;
 		if (nhandle != handle)
 			return -EINVAL;
 	}

 	h1 = to_hash(nhandle);
 	b = rtnl_dereference(head->table[h1]);
 	if (!b) {
 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 		if (b == NULL)
 			return -ENOBUFS;

 		rcu_assign_pointer(head->table[h1], b);
 	} else {
 		unsigned int h2 = from_hash(nhandle >> 16);

 		for (fp = rtnl_dereference(b->ht[h2]);
 		     fp;
 		     fp = rtnl_dereference(fp->next))
 			if (fp->handle == f->handle)
 				return -EEXIST;
 	}

 	if (tb[TCA_ROUTE4_TO])
 		f->id = to;

 	if (tb[TCA_ROUTE4_FROM])
 		f->id = to | id<<16;
 	else if (tb[TCA_ROUTE4_IIF])
 		f->iif = id;

 	f->handle = nhandle;
 	f->bkt = b;
 	f->tp = tp;

 	if (tb[TCA_ROUTE4_CLASSID]) {
 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
 		tcf_bind_filter(tp, &f->res, base);
 	}

 	return 0;
 }

 static int route4_change(struct net *net, struct sk_buff *in_skb,
 			 struct tcf_proto *tp, unsigned long base, u32 handle,
 			 struct nlattr **tca, void **arg, bool ovr,
 			 bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	struct route4_filter __rcu **fp;
 	struct route4_filter *fold, *f1, *pfp, *f = NULL;
 	struct route4_bucket *b;
 	struct nlattr *opt = tca[TCA_OPTIONS];
 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 	unsigned int h, th;
 	int err;
 	bool new = true;

 	if (opt == NULL)
 		return handle ? -EINVAL : 0;

 	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
 	if (err < 0)
 		return err;

 	fold = *arg;
 	if (fold && handle && fold->handle != handle)
 			return -EINVAL;

 	err = -ENOBUFS;
 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
 	if (!f)
 		goto errout;

 	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
 	if (err < 0)
 		goto errout;

 	if (fold) {
 		f->id = fold->id;
 		f->iif = fold->iif;
 		f->res = fold->res;
 		f->handle = fold->handle;

 		f->tp = fold->tp;
 		f->bkt = fold->bkt;
 		new = false;
 	}

 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
 			       tca[TCA_RATE], new, ovr, extack);
 	if (err < 0)
 		goto errout;

 	h = from_hash(f->handle >> 16);
 	fp = &f->bkt->ht[h];
 	for (pfp = rtnl_dereference(*fp);
 	     (f1 = rtnl_dereference(*fp)) != NULL;
 	     fp = &f1->next)
 		if (f->handle < f1->handle)
 			break;

 	tcf_block_netif_keep_dst(tp->chain->block);
 	rcu_assign_pointer(f->next, f1);
 	rcu_assign_pointer(*fp, f);

 	if (fold && fold->handle && f->handle != fold->handle) {
 		th = to_hash(fold->handle);
 		h = from_hash(fold->handle >> 16);
 		b = rtnl_dereference(head->table[th]);
 		if (b) {
 			fp = &b->ht[h];
 			for (pfp = rtnl_dereference(*fp); pfp;
 			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
 				if (pfp == f) {
 					*fp = f->next;
 					break;
 				}
 			}
 		}
 	}

 	route4_reset_fastmap(head);
 	*arg = f;
 	if (fold) {
 		tcf_unbind_filter(tp, &fold->res);
 		tcf_exts_get_net(&fold->exts);
 		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
 	}
 	return 0;

 errout:
 	if (f)
 		tcf_exts_destroy(&f->exts);
 	kfree(f);
 	return err;
 }

 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 			bool rtnl_held)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	unsigned int h, h1;

 	if (head == NULL || arg->stop)
 		return;

 	for (h = 0; h <= 256; h++) {
 		struct route4_bucket *b = rtnl_dereference(head->table[h]);

 		if (b) {
 			for (h1 = 0; h1 <= 32; h1++) {
 				struct route4_filter *f;

 				for (f = rtnl_dereference(b->ht[h1]);
 				     f;
 				     f = rtnl_dereference(f->next)) {
 					if (arg->count < arg->skip) {
 						arg->count++;
 						continue;
 					}
 					if (arg->fn(tp, f, arg) < 0) {
 						arg->stop = 1;
 						return;
 					}
 					arg->count++;
 				}
 			}
 		}
 	}
 }

 static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
 		       struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 {
 	struct route4_filter *f = fh;
 	struct nlattr *nest;
 	u32 id;

 	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->handle & 0x8000)) {
 		id = f->id & 0xFF;
 		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
 			goto nla_put_failure;
 	}
 	if (f->handle & 0x80000000) {
 		if ((f->handle >> 16) != 0xFFFF &&
 		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
 			goto nla_put_failure;
 	} else {
 		id = f->id >> 16;
 		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
 			goto nla_put_failure;
 	}
 	if (f->res.classid &&
 	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
 		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 void route4_bind_class(void *fh, u32 classid, unsigned long cl)
 {
 	struct route4_filter *f = fh;

 	if (f && f->res.classid == classid)
 		f->res.class = cl;
 }

 static struct tcf_proto_ops cls_route4_ops __read_mostly = {
 	.kind		=	"route",
 	.classify	=	route4_classify,
 	.init		=	route4_init,
 	.destroy	=	route4_destroy,
 	.get		=	route4_get,
 	.change		=	route4_change,
 	.delete		=	route4_delete,
 	.walk		=	route4_walk,
 	.dump		=	route4_dump,
 	.bind_class	=	route4_bind_class,
 	.owner		=	THIS_MODULE,
 };

 static int __init init_route4(void)
 {
 	return register_tcf_proto_ops(&cls_route4_ops);
 }

 static void __exit exit_route4(void)
 {
 	unregister_tcf_proto_ops(&cls_route4_ops);
 }

 module_init(init_route4)
 module_exit(exit_route4)
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* net/sched/cls_route.c ROUTE4 classifier.
	*
	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	*/

	#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/dst.h>
	#include <net/route.h>
	#include <net/netlink.h>
	#include <net/act_api.h>
	#include <net/pkt_cls.h>

	/*
	* 1. For now we assume that route tags < 256.
	* It allows to use direct table lookups, instead of hash tables.
	* 2. For now we assume that "from TAG" and "fromdev DEV" statements
	* are mutually exclusive.
	* 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
	*/
	struct route4_fastmap {
	struct route4_filter *filter;
	u32 id;
	int iif;
	};

	struct route4_head {
	struct route4_fastmap fastmap[16];
	struct route4_bucket __rcu *table[256 + 1];
	struct rcu_head rcu;
	};

	struct route4_bucket {
	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
	struct route4_filter __rcu *ht[16 + 16 + 1];
	struct rcu_head rcu;
	};

	struct route4_filter {
	struct route4_filter __rcu *next;
	u32 id;
	int iif;

	struct tcf_result res;
	struct tcf_exts exts;
	u32 handle;
	struct route4_bucket *bkt;
	struct tcf_proto *tp;
	struct rcu_work rwork;
	};

	#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))

	static inline int route4_fastmap_hash(u32 id, int iif)
	{
	return id & 0xF;
	}

	static DEFINE_SPINLOCK(fastmap_lock);
	static void
	route4_reset_fastmap(struct route4_head *head)
	{
	spin_lock_bh(&fastmap_lock);
	memset(head->fastmap, 0, sizeof(head->fastmap));
	spin_unlock_bh(&fastmap_lock);
	}

	static void
	route4_set_fastmap(struct route4_head *head, u32 id, int iif,
	struct route4_filter *f)
	{
	int h = route4_fastmap_hash(id, iif);

	/* fastmap updates must look atomic to aling id, iff, filter */
	spin_lock_bh(&fastmap_lock);
	head->fastmap[h].id = id;
	head->fastmap[h].iif = iif;
	head->fastmap[h].filter = f;
	spin_unlock_bh(&fastmap_lock);
	}

	static inline int route4_hash_to(u32 id)
	{
	return id & 0xFF;
	}

	static inline int route4_hash_from(u32 id)
	{
	return (id >> 16) & 0xF;
	}

	static inline int route4_hash_iif(int iif)
	{
	return 16 + ((iif >> 16) & 0xF);
	}

	static inline int route4_hash_wild(void)
	{
	return 32;
	}

	#define ROUTE4_APPLY_RESULT() \
	{ \
	*res = f->res; \
	if (tcf_exts_has_actions(&f->exts)) { \
	int r = tcf_exts_exec(skb, &f->exts, res); \
	if (r < 0) { \
	dont_cache = 1; \
	continue; \
	} \
	return r; \
	} else if (!dont_cache) \
	route4_set_fastmap(head, id, iif, f); \
	return 0; \
	}

	static int route4_classify(struct sk_buff skb, const struct tcf_proto tp,
	struct tcf_result *res)
	{
	struct route4_head *head = rcu_dereference_bh(tp->root);
	struct dst_entry *dst;
	struct route4_bucket *b;
	struct route4_filter *f;
	u32 id, h;
	int iif, dont_cache = 0;

	dst = skb_dst(skb);
	if (!dst)
	goto failure;

	id = dst->tclassid;

	iif = inet_iif(skb);

	h = route4_fastmap_hash(id, iif);

	spin_lock(&fastmap_lock);
	if (id == head->fastmap[h].id &&
	iif == head->fastmap[h].iif &&
	(f = head->fastmap[h].filter) != NULL) {
	if (f == ROUTE4_FAILURE) {
	spin_unlock(&fastmap_lock);
	goto failure;
	}

	*res = f->res;
	spin_unlock(&fastmap_lock);
	return 0;
	}
	spin_unlock(&fastmap_lock);

	h = route4_hash_to(id);

	restart:
	b = rcu_dereference_bh(head->table[h]);
	if (b) {
	for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
	f;
	f = rcu_dereference_bh(f->next))
	if (f->id == id)
	ROUTE4_APPLY_RESULT();

	for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
	f;
	f = rcu_dereference_bh(f->next))
	if (f->iif == iif)
	ROUTE4_APPLY_RESULT();

	for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
	f;
	f = rcu_dereference_bh(f->next))
	ROUTE4_APPLY_RESULT();
	}
	if (h < 256) {
	h = 256;
	id &= ~0xFFFF;
	goto restart;
	}

	if (!dont_cache)
	route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
	failure:
	return -1;
	}

	static inline u32 to_hash(u32 id)
	{
	u32 h = id & 0xFF;

	if (id & 0x8000)
	h += 256;
	return h;
	}

	static inline u32 from_hash(u32 id)
	{
	id &= 0xFFFF;
	if (id == 0xFFFF)
	return 32;
	if (!(id & 0x8000)) {
	if (id > 255)
	return 256;
	return id & 0xF;
	}
	return 16 + (id & 0xF);
	}

	static void route4_get(struct tcf_proto tp, u32 handle)
	{
	struct route4_head *head = rtnl_dereference(tp->root);
	struct route4_bucket *b;
	struct route4_filter *f;
	unsigned int h1, h2;

	h1 = to_hash(handle);
	if (h1 > 256)
	return NULL;

	h2 = from_hash(handle >> 16);
	if (h2 > 32)
	return NULL;

	b = rtnl_dereference(head->table[h1]);
	if (b) {
	for (f = rtnl_dereference(b->ht[h2]);
	f;
	f = rtnl_dereference(f->next))
	if (f->handle == handle)
	return f;
	}
	return NULL;
	}

	static int route4_init(struct tcf_proto *tp)
	{
	struct route4_head *head;

	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
	if (head == NULL)
	return -ENOBUFS;

	rcu_assign_pointer(tp->root, head);
	return 0;
	}

	static void __route4_delete_filter(struct route4_filter *f)
	{
	tcf_exts_destroy(&f->exts);
	tcf_exts_put_net(&f->exts);
	kfree(f);
	}

	static void route4_delete_filter_work(struct work_struct *work)
	{
	struct route4_filter *f = container_of(to_rcu_work(work),
	struct route4_filter,
	rwork);
	rtnl_lock();
	__route4_delete_filter(f);
	rtnl_unlock();
	}

	static void route4_queue_work(struct route4_filter *f)
	{
	tcf_queue_work(&f->rwork, route4_delete_filter_work);
	}

	static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
	struct netlink_ext_ack *extack)
	{
	struct route4_head *head = rtnl_dereference(tp->root);
	int h1, h2;

	if (head == NULL)
	return;

	for (h1 = 0; h1 <= 256; h1++) {
	struct route4_bucket *b;

	b = rtnl_dereference(head->table[h1]);
	if (b) {
	for (h2 = 0; h2 <= 32; h2++) {
	struct route4_filter *f;

	while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
	struct route4_filter *next;

	next = rtnl_dereference(f->next);
	RCU_INIT_POINTER(b->ht[h2], next);
	tcf_unbind_filter(tp, &f->res);
	if (tcf_exts_get_net(&f->exts))
	route4_queue_work(f);
	else
	__route4_delete_filter(f);
	}
	}
	RCU_INIT_POINTER(head->table[h1], NULL);
	kfree_rcu(b, rcu);
	}
	}
	kfree_rcu(head, rcu);
	}

	static int route4_delete(struct tcf_proto tp, void arg, bool *last,
	bool rtnl_held, struct netlink_ext_ack *extack)
	{
	struct route4_head *head = rtnl_dereference(tp->root);
	struct route4_filter *f = arg;
	struct route4_filter __rcu **fp;
	struct route4_filter *nf;
	struct route4_bucket *b;
	unsigned int h = 0;
	int i, h1;

	if (!head \|\| !f)
	return -EINVAL;

	h = f->handle;
	b = f->bkt;

	fp = &b->ht[from_hash(h >> 16)];
	for (nf = rtnl_dereference(*fp); nf;
	fp = &nf->next, nf = rtnl_dereference(*fp)) {
	if (nf == f) {
	/* unlink it */
	RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));

	/* Remove any fastmap lookups that might ref filter
	* notice we unlink'd the filter so we can't get it
	* back in the fastmap.
	*/
	route4_reset_fastmap(head);

	/* Delete it */
	tcf_unbind_filter(tp, &f->res);
	tcf_exts_get_net(&f->exts);
	tcf_queue_work(&f->rwork, route4_delete_filter_work);

	/* Strip RTNL protected tree */
	for (i = 0; i <= 32; i++) {
	struct route4_filter *rt;

	rt = rtnl_dereference(b->ht[i]);
	if (rt)
	goto out;
	}

	/* OK, session has no flows */
	RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
	kfree_rcu(b, rcu);
	break;
	}
	}

	out:
	*last = true;
	for (h1 = 0; h1 <= 256; h1++) {
	if (rcu_access_pointer(head->table[h1])) {
	*last = false;
	break;
	}
	}

	return 0;
	}

	static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
	[TCA_ROUTE4_CLASSID] = { .type = NLA_U32 },
	[TCA_ROUTE4_TO] = { .type = NLA_U32 },
	[TCA_ROUTE4_FROM] = { .type = NLA_U32 },
	[TCA_ROUTE4_IIF] = { .type = NLA_U32 },
	};

	static int route4_set_parms(struct net net, struct tcf_proto tp,
	unsigned long base, struct route4_filter *f,
	u32 handle, struct route4_head *head,
	struct nlattr *tb, struct nlattr est, int new,
	bool ovr, struct netlink_ext_ack *extack)
	{
	u32 id = 0, to = 0, nhandle = 0x8000;
	struct route4_filter *fp;
	unsigned int h1;
	struct route4_bucket *b;
	int err;

	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
	if (err < 0)
	return err;

	if (tb[TCA_ROUTE4_TO]) {
	if (new && handle & 0x8000)
	return -EINVAL;
	to = nla_get_u32(tb[TCA_ROUTE4_TO]);
	if (to > 0xFF)
	return -EINVAL;
	nhandle = to;
	}

	if (tb[TCA_ROUTE4_FROM]) {
	if (tb[TCA_ROUTE4_IIF])
	return -EINVAL;
	id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
	if (id > 0xFF)
	return -EINVAL;
	nhandle \|= id << 16;
	} else if (tb[TCA_ROUTE4_IIF]) {
	id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
	if (id > 0x7FFF)
	return -EINVAL;
	nhandle \|= (id \| 0x8000) << 16;
	} else
	nhandle \|= 0xFFFF << 16;

	if (handle && new) {
	nhandle \|= handle & 0x7F00;
	if (nhandle != handle)
	return -EINVAL;
	}

	h1 = to_hash(nhandle);
	b = rtnl_dereference(head->table[h1]);
	if (!b) {
	b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
	if (b == NULL)
	return -ENOBUFS;

	rcu_assign_pointer(head->table[h1], b);
	} else {
	unsigned int h2 = from_hash(nhandle >> 16);

	for (fp = rtnl_dereference(b->ht[h2]);
	fp;
	fp = rtnl_dereference(fp->next))
	if (fp->handle == f->handle)
	return -EEXIST;
	}

	if (tb[TCA_ROUTE4_TO])
	f->id = to;

	if (tb[TCA_ROUTE4_FROM])
	f->id = to \| id<<16;
	else if (tb[TCA_ROUTE4_IIF])
	f->iif = id;

	f->handle = nhandle;
	f->bkt = b;
	f->tp = tp;

	if (tb[TCA_ROUTE4_CLASSID]) {
	f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
	tcf_bind_filter(tp, &f->res, base);
	}

	return 0;
	}

	static int route4_change(struct net net, struct sk_buff in_skb,
	struct tcf_proto *tp, unsigned long base, u32 handle,
	struct nlattr tca, void arg, bool ovr,
	bool rtnl_held, struct netlink_ext_ack *extack)
	{
	struct route4_head *head = rtnl_dereference(tp->root);
	struct route4_filter __rcu **fp;
	struct route4_filter fold, f1, pfp, f = NULL;
	struct route4_bucket *b;
	struct nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
	unsigned int h, th;
	int err;
	bool new = true;

	if (opt == NULL)
	return handle ? -EINVAL : 0;

	err = nla_parse_nested(tb, TCA_ROUTE4_MAX, opt, route4_policy, NULL);
	if (err < 0)
	return err;

	fold = *arg;
	if (fold && handle && fold->handle != handle)
	return -EINVAL;

	err = -ENOBUFS;
	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
	if (!f)
	goto errout;

	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
	if (err < 0)
	goto errout;

	if (fold) {
	f->id = fold->id;
	f->iif = fold->iif;
	f->res = fold->res;
	f->handle = fold->handle;

	f->tp = fold->tp;
	f->bkt = fold->bkt;
	new = false;
	}

	err = route4_set_parms(net, tp, base, f, handle, head, tb,
	tca[TCA_RATE], new, ovr, extack);
	if (err < 0)
	goto errout;

	h = from_hash(f->handle >> 16);
	fp = &f->bkt->ht[h];
	for (pfp = rtnl_dereference(*fp);
	(f1 = rtnl_dereference(*fp)) != NULL;
	fp = &f1->next)
	if (f->handle < f1->handle)
	break;

	tcf_block_netif_keep_dst(tp->chain->block);
	rcu_assign_pointer(f->next, f1);
	rcu_assign_pointer(*fp, f);

	if (fold && fold->handle && f->handle != fold->handle) {
	th = to_hash(fold->handle);
	h = from_hash(fold->handle >> 16);
	b = rtnl_dereference(head->table[th]);
	if (b) {
	fp = &b->ht[h];
	for (pfp = rtnl_dereference(*fp); pfp;
	fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
	if (pfp == f) {
	*fp = f->next;
	break;
	}
	}
	}
	}

	route4_reset_fastmap(head);
	*arg = f;
	if (fold) {
	tcf_unbind_filter(tp, &fold->res);
	tcf_exts_get_net(&fold->exts);
	tcf_queue_work(&fold->rwork, route4_delete_filter_work);
	}
	return 0;

	errout:
	if (f)
	tcf_exts_destroy(&f->exts);
	kfree(f);
	return err;
	}

	static void route4_walk(struct tcf_proto tp, struct tcf_walker arg,
	bool rtnl_held)
	{
	struct route4_head *head = rtnl_dereference(tp->root);
	unsigned int h, h1;

	if (head == NULL \|\| arg->stop)
	return;

	for (h = 0; h <= 256; h++) {
	struct route4_bucket *b = rtnl_dereference(head->table[h]);

	if (b) {
	for (h1 = 0; h1 <= 32; h1++) {
	struct route4_filter *f;

	for (f = rtnl_dereference(b->ht[h1]);
	f;
	f = rtnl_dereference(f->next)) {
	if (arg->count < arg->skip) {
	arg->count++;
	continue;
	}
	if (arg->fn(tp, f, arg) < 0) {
	arg->stop = 1;
	return;
	}
	arg->count++;
	}
	}
	}
	}
	}

	static int route4_dump(struct net net, struct tcf_proto tp, void *fh,
	struct sk_buff skb, struct tcmsg t, bool rtnl_held)
	{
	struct route4_filter *f = fh;
	struct nlattr *nest;
	u32 id;

	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->handle & 0x8000)) {
	id = f->id & 0xFF;
	if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
	goto nla_put_failure;
	}
	if (f->handle & 0x80000000) {
	if ((f->handle >> 16) != 0xFFFF &&
	nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
	goto nla_put_failure;
	} else {
	id = f->id >> 16;
	if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
	goto nla_put_failure;
	}
	if (f->res.classid &&
	nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
	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 void route4_bind_class(void *fh, u32 classid, unsigned long cl)
	{
	struct route4_filter *f = fh;

	if (f && f->res.classid == classid)
	f->res.class = cl;
	}

	static struct tcf_proto_ops cls_route4_ops __read_mostly = {
	.kind = "route",
	.classify = route4_classify,
	.init = route4_init,
	.destroy = route4_destroy,
	.get = route4_get,
	.change = route4_change,
	.delete = route4_delete,
	.walk = route4_walk,
	.dump = route4_dump,
	.bind_class = route4_bind_class,
	.owner = THIS_MODULE,
	};

	static int __init init_route4(void)
	{
	return register_tcf_proto_ops(&cls_route4_ops);
	}

	static void __exit exit_route4(void)
	{
	unregister_tcf_proto_ops(&cls_route4_ops);
	}

	module_init(init_route4)
	module_exit(exit_route4)
	MODULE_LICENSE("GPL");