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

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
  *
  * 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
  */

 #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>
 #include <net/sch_generic.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;
 	int			ifindex;
 	struct tcf_exts		exts;
 	struct tcf_proto	*tp;
 	struct rcu_work		rwork;
 };

 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;
 				if (!tcf_match_indev(skb, f->ifindex))
 					continue;
 				r = tcf_exts_exec(skb, &f->exts, res);
 				if (r < 0)
 					continue;

 				return r;
 			}
 		}
 	} else {
 		struct Qdisc *q = tcf_block_q(tp->chain->block);

 		/* Old method: classify the packet using its skb mark. */
 		if (id && (TC_H_MAJ(id) == 0 ||
 			   !(TC_H_MAJ(id ^ q->handle)))) {
 			res->classid = id;
 			res->class = 0;
 			return 0;
 		}
 	}

 	return -1;
 }

 static void *fw_get(struct tcf_proto *tp, u32 handle)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f;

 	if (head == NULL)
 		return NULL;

 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
 	for (; f; f = rtnl_dereference(f->next)) {
 		if (f->id == handle)
 			return f;
 	}
 	return NULL;
 }

 static int fw_init(struct tcf_proto *tp)
 {
 	/* We don't allocate fw_head here, because in the old method
 	 * we don't need it at all.
 	 */
 	return 0;
 }

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

 static void fw_delete_filter_work(struct work_struct *work)
 {
 	struct fw_filter *f = container_of(to_rcu_work(work),
 					   struct fw_filter,
 					   rwork);
 	rtnl_lock();
 	__fw_delete_filter(f);
 	rtnl_unlock();
 }

 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
 		       struct netlink_ext_ack *extack)
 {
 	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);
 			if (tcf_exts_get_net(&f->exts))
 				tcf_queue_work(&f->rwork, fw_delete_filter_work);
 			else
 				__fw_delete_filter(f);
 		}
 	}
 	kfree_rcu(head, rcu);
 }

 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
 		     bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f = arg;
 	struct fw_filter __rcu **fp;
 	struct fw_filter *pfp;
 	int ret = -EINVAL;
 	int h;

 	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);
 			tcf_exts_get_net(&f->exts);
 			tcf_queue_work(&f->rwork, fw_delete_filter_work);
 			ret = 0;
 			break;
 		}
 	}

 	*last = true;
 	for (h = 0; h < HTSIZE; h++) {
 		if (rcu_access_pointer(head->ht[h])) {
 			*last = false;
 			break;
 		}
 	}

 out:
 	return ret;
 }

 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_set_parms(struct net *net, struct tcf_proto *tp,
 			struct fw_filter *f, struct nlattr **tb,
 			struct nlattr **tca, unsigned long base, u32 flags,
 			struct netlink_ext_ack *extack)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	u32 mask;
 	int err;

 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, flags,
 				extack);
 	if (err < 0)
 		return err;

 	if (tb[TCA_FW_INDEV]) {
 		int ret;
 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
 		if (ret < 0)
 			return ret;
 		f->ifindex = ret;
 	}

 	err = -EINVAL;
 	if (tb[TCA_FW_MASK]) {
 		mask = nla_get_u32(tb[TCA_FW_MASK]);
 		if (mask != head->mask)
 			return err;
 	} else if (head->mask != 0xFFFFFFFF)
 		return err;

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

 	return 0;
 }

 static int fw_change(struct net *net, struct sk_buff *in_skb,
 		     struct tcf_proto *tp, unsigned long base,
 		     u32 handle, struct nlattr **tca, void **arg,
 		     u32 flags, struct netlink_ext_ack *extack)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f = *arg;
 	struct nlattr *opt = tca[TCA_OPTIONS];
 	struct nlattr *tb[TCA_FW_MAX + 1];
 	int err;

 	if (!opt)
 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */

 	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
 					  NULL);
 	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->ifindex = f->ifindex;
 		fnew->tp = f->tp;

 		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
 				    TCA_FW_POLICE);
 		if (err < 0) {
 			kfree(fnew);
 			return err;
 		}

 		err = fw_set_parms(net, tp, fnew, tb, tca, base, flags, extack);
 		if (err < 0) {
 			tcf_exts_destroy(&fnew->exts);
 			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);
 		tcf_exts_get_net(&f->exts);
 		tcf_queue_work(&f->rwork, fw_delete_filter_work);

 		*arg = fnew;
 		return err;
 	}

 	if (!handle)
 		return -EINVAL;

 	if (!head) {
 		u32 mask = 0xFFFFFFFF;
 		if (tb[TCA_FW_MASK])
 			mask = nla_get_u32(tb[TCA_FW_MASK]);

 		head = kzalloc(sizeof(*head), GFP_KERNEL);
 		if (!head)
 			return -ENOBUFS;
 		head->mask = mask;

 		rcu_assign_pointer(tp->root, head);
 	}

 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
 	if (f == NULL)
 		return -ENOBUFS;

 	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
 	if (err < 0)
 		goto errout;
 	f->id = handle;
 	f->tp = tp;

 	err = fw_set_parms(net, tp, f, tb, tca, base, flags, extack);
 	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 = f;
 	return 0;

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

 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 		    bool rtnl_held)
 {
 	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 (!tc_cls_stats_dump(tp, arg, f))
 				return;
 		}
 	}
 }

 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
 		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f = fh;
 	struct nlattr *nest;

 	if (f == NULL)
 		return skb->len;

 	t->tcm_handle = f->id;

 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
 		return skb->len;

 	nest = nla_nest_start_noflag(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;
 	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;
 	}
 	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 void fw_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
 			  unsigned long base)
 {
 	struct fw_filter *f = fh;

 	tc_cls_bind_class(classid, cl, q, &f->res, base);
 }

 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,
 	.bind_class	=	fw_bind_class,
 	.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");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* net/sched/cls_fw.c Classifier mapping ipchains' fwmark to traffic class.
	*
	* 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
	*/

	#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>
	#include <net/sch_generic.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;
	int ifindex;
	struct tcf_exts exts;
	struct tcf_proto *tp;
	struct rcu_work rwork;
	};

	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;
	if (!tcf_match_indev(skb, f->ifindex))
	continue;
	r = tcf_exts_exec(skb, &f->exts, res);
	if (r < 0)
	continue;

	return r;
	}
	}
	} else {
	struct Qdisc *q = tcf_block_q(tp->chain->block);

	/* Old method: classify the packet using its skb mark. */
	if (id && (TC_H_MAJ(id) == 0 \|\|
	!(TC_H_MAJ(id ^ q->handle)))) {
	res->classid = id;
	res->class = 0;
	return 0;
	}
	}

	return -1;
	}

	static void fw_get(struct tcf_proto tp, u32 handle)
	{
	struct fw_head *head = rtnl_dereference(tp->root);
	struct fw_filter *f;

	if (head == NULL)
	return NULL;

	f = rtnl_dereference(head->ht[fw_hash(handle)]);
	for (; f; f = rtnl_dereference(f->next)) {
	if (f->id == handle)
	return f;
	}
	return NULL;
	}

	static int fw_init(struct tcf_proto *tp)
	{
	/* We don't allocate fw_head here, because in the old method
	* we don't need it at all.
	*/
	return 0;
	}

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

	static void fw_delete_filter_work(struct work_struct *work)
	{
	struct fw_filter *f = container_of(to_rcu_work(work),
	struct fw_filter,
	rwork);
	rtnl_lock();
	__fw_delete_filter(f);
	rtnl_unlock();
	}

	static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
	struct netlink_ext_ack *extack)
	{
	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);
	if (tcf_exts_get_net(&f->exts))
	tcf_queue_work(&f->rwork, fw_delete_filter_work);
	else
	__fw_delete_filter(f);
	}
	}
	kfree_rcu(head, rcu);
	}

	static int fw_delete(struct tcf_proto tp, void arg, bool *last,
	bool rtnl_held, struct netlink_ext_ack *extack)
	{
	struct fw_head *head = rtnl_dereference(tp->root);
	struct fw_filter *f = arg;
	struct fw_filter __rcu **fp;
	struct fw_filter *pfp;
	int ret = -EINVAL;
	int h;

	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);
	tcf_exts_get_net(&f->exts);
	tcf_queue_work(&f->rwork, fw_delete_filter_work);
	ret = 0;
	break;
	}
	}

	*last = true;
	for (h = 0; h < HTSIZE; h++) {
	if (rcu_access_pointer(head->ht[h])) {
	*last = false;
	break;
	}
	}

	out:
	return ret;
	}

	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_set_parms(struct net net, struct tcf_proto tp,
	struct fw_filter f, struct nlattr *tb,
	struct nlattr **tca, unsigned long base, u32 flags,
	struct netlink_ext_ack *extack)
	{
	struct fw_head *head = rtnl_dereference(tp->root);
	u32 mask;
	int err;

	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, flags,
	extack);
	if (err < 0)
	return err;

	if (tb[TCA_FW_INDEV]) {
	int ret;
	ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
	if (ret < 0)
	return ret;
	f->ifindex = ret;
	}

	err = -EINVAL;
	if (tb[TCA_FW_MASK]) {
	mask = nla_get_u32(tb[TCA_FW_MASK]);
	if (mask != head->mask)
	return err;
	} else if (head->mask != 0xFFFFFFFF)
	return err;

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

	return 0;
	}

	static int fw_change(struct net net, struct sk_buff in_skb,
	struct tcf_proto *tp, unsigned long base,
	u32 handle, struct nlattr tca, void arg,
	u32 flags, struct netlink_ext_ack *extack)
	{
	struct fw_head *head = rtnl_dereference(tp->root);
	struct fw_filter f = arg;
	struct nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_FW_MAX + 1];
	int err;

	if (!opt)
	return handle ? -EINVAL : 0; /* Succeed if it is old method. */

	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
	NULL);
	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->ifindex = f->ifindex;
	fnew->tp = f->tp;

	err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
	TCA_FW_POLICE);
	if (err < 0) {
	kfree(fnew);
	return err;
	}

	err = fw_set_parms(net, tp, fnew, tb, tca, base, flags, extack);
	if (err < 0) {
	tcf_exts_destroy(&fnew->exts);
	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);
	tcf_exts_get_net(&f->exts);
	tcf_queue_work(&f->rwork, fw_delete_filter_work);

	*arg = fnew;
	return err;
	}

	if (!handle)
	return -EINVAL;

	if (!head) {
	u32 mask = 0xFFFFFFFF;
	if (tb[TCA_FW_MASK])
	mask = nla_get_u32(tb[TCA_FW_MASK]);

	head = kzalloc(sizeof(*head), GFP_KERNEL);
	if (!head)
	return -ENOBUFS;
	head->mask = mask;

	rcu_assign_pointer(tp->root, head);
	}

	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
	if (f == NULL)
	return -ENOBUFS;

	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
	if (err < 0)
	goto errout;
	f->id = handle;
	f->tp = tp;

	err = fw_set_parms(net, tp, f, tb, tca, base, flags, extack);
	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 = f;
	return 0;

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

	static void fw_walk(struct tcf_proto tp, struct tcf_walker arg,
	bool rtnl_held)
	{
	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 (!tc_cls_stats_dump(tp, arg, f))
	return;
	}
	}
	}

	static int fw_dump(struct net net, struct tcf_proto tp, void *fh,
	struct sk_buff skb, struct tcmsg t, bool rtnl_held)
	{
	struct fw_head *head = rtnl_dereference(tp->root);
	struct fw_filter *f = fh;
	struct nlattr *nest;

	if (f == NULL)
	return skb->len;

	t->tcm_handle = f->id;

	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
	return skb->len;

	nest = nla_nest_start_noflag(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;
	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;
	}
	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 void fw_bind_class(void fh, u32 classid, unsigned long cl, void q,
	unsigned long base)
	{
	struct fw_filter *f = fh;

	tc_cls_bind_class(classid, cl, q, &f->res, base);
	}

	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,
	.bind_class = fw_bind_class,
	.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");