net/sched/cls_api.c - arm/linux - Git at Google

 /*
  * net/sched/cls_api.c	Packet classifier API.
  *
  *		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:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  *
  * Changes:
  *
  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
  *
  */

 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/netlink.h>
 #include <linux/err.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/pkt_cls.h>

 /* The list of all installed classifier types */

 static struct tcf_proto_ops *tcf_proto_base __read_mostly;

 /* Protects list of registered TC modules. It is pure SMP lock. */
 static DEFINE_RWLOCK(cls_mod_lock);

 /* Find classifier type by string name */

 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
 {
 	struct tcf_proto_ops *t = NULL;

 	if (kind) {
 		read_lock(&cls_mod_lock);
 		for (t = tcf_proto_base; t; t = t->next) {
 			if (nla_strcmp(kind, t->kind) == 0) {
 				if (!try_module_get(t->owner))
 					t = NULL;
 				break;
 			}
 		}
 		read_unlock(&cls_mod_lock);
 	}
 	return t;
 }

 /* Register(unregister) new classifier type */

 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
 {
 	struct tcf_proto_ops *t, **tp;
 	int rc = -EEXIST;

 	write_lock(&cls_mod_lock);
 	for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
 		if (!strcmp(ops->kind, t->kind))
 			goto out;

 	ops->next = NULL;
 	*tp = ops;
 	rc = 0;
 out:
 	write_unlock(&cls_mod_lock);
 	return rc;
 }
 EXPORT_SYMBOL(register_tcf_proto_ops);

 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
 {
 	struct tcf_proto_ops *t, **tp;
 	int rc = -ENOENT;

 	write_lock(&cls_mod_lock);
 	for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
 		if (t == ops)
 			break;

 	if (!t)
 		goto out;
 	*tp = t->next;
 	rc = 0;
 out:
 	write_unlock(&cls_mod_lock);
 	return rc;
 }
 EXPORT_SYMBOL(unregister_tcf_proto_ops);

 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 			  struct tcf_proto *tp, unsigned long fh, int event);


 /* Select new prio value from the range, managed by kernel. */

 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 {
 	u32 first = TC_H_MAKE(0xC0000000U, 0U);

 	if (tp)
 		first = tp->prio-1;

 	return first;
 }

 /* Add/change/delete/get a filter node */

 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nlattr *tca[TCA_MAX + 1];
 	struct tcmsg *t;
 	u32 protocol;
 	u32 prio;
 	u32 nprio;
 	u32 parent;
 	struct net_device *dev;
 	struct Qdisc  *q;
 	struct tcf_proto **back, **chain;
 	struct tcf_proto *tp;
 	struct tcf_proto_ops *tp_ops;
 	const struct Qdisc_class_ops *cops;
 	unsigned long cl;
 	unsigned long fh;
 	int err;

 	if (net != &init_net)
 		return -EINVAL;

 replay:
 	t = NLMSG_DATA(n);
 	protocol = TC_H_MIN(t->tcm_info);
 	prio = TC_H_MAJ(t->tcm_info);
 	nprio = prio;
 	parent = t->tcm_parent;
 	cl = 0;

 	if (prio == 0) {
 		/* If no priority is given, user wants we allocated it. */
 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 			return -ENOENT;
 		prio = TC_H_MAKE(0x80000000U, 0U);
 	}

 	/* Find head of filter chain. */

 	/* Find link */
 	dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
 	if (dev == NULL)
 		return -ENODEV;

 	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 	if (err < 0)
 		return err;

 	/* Find qdisc */
 	if (!parent) {
 		struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
 		q = dev_queue->qdisc_sleeping;
 		parent = q->handle;
 	} else {
 		q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 		if (q == NULL)
 			return -EINVAL;
 	}

 	/* Is it classful? */
 	if ((cops = q->ops->cl_ops) == NULL)
 		return -EINVAL;

 	/* Do we search for filter, attached to class? */
 	if (TC_H_MIN(parent)) {
 		cl = cops->get(q, parent);
 		if (cl == 0)
 			return -ENOENT;
 	}

 	/* And the last stroke */
 	chain = cops->tcf_chain(q, cl);
 	err = -EINVAL;
 	if (chain == NULL)
 		goto errout;

 	/* Check the chain for existence of proto-tcf with this priority */
 	for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 		if (tp->prio >= prio) {
 			if (tp->prio == prio) {
 				if (!nprio || (tp->protocol != protocol && protocol))
 					goto errout;
 			} else
 				tp = NULL;
 			break;
 		}
 	}

 	if (tp == NULL) {
 		/* Proto-tcf does not exist, create new one */

 		if (tca[TCA_KIND] == NULL || !protocol)
 			goto errout;

 		err = -ENOENT;
 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 			goto errout;


 		/* Create new proto tcf */

 		err = -ENOBUFS;
 		tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 		if (tp == NULL)
 			goto errout;
 		err = -ENOENT;
 		tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 		if (tp_ops == NULL) {
 #ifdef CONFIG_KMOD
 			struct nlattr *kind = tca[TCA_KIND];
 			char name[IFNAMSIZ];

 			if (kind != NULL &&
 			    nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 				rtnl_unlock();
 				request_module("cls_%s", name);
 				rtnl_lock();
 				tp_ops = tcf_proto_lookup_ops(kind);
 				/* We dropped the RTNL semaphore in order to
 				 * perform the module load.  So, even if we
 				 * succeeded in loading the module we have to
 				 * replay the request.  We indicate this using
 				 * -EAGAIN.
 				 */
 				if (tp_ops != NULL) {
 					module_put(tp_ops->owner);
 					err = -EAGAIN;
 				}
 			}
 #endif
 			kfree(tp);
 			goto errout;
 		}
 		tp->ops = tp_ops;
 		tp->protocol = protocol;
 		tp->prio = nprio ? : tcf_auto_prio(*back);
 		tp->q = q;
 		tp->classify = tp_ops->classify;
 		tp->classid = parent;

 		err = tp_ops->init(tp);
 		if (err != 0) {
 			module_put(tp_ops->owner);
 			kfree(tp);
 			goto errout;
 		}

 		qdisc_lock_tree(dev);
 		tp->next = *back;
 		*back = tp;
 		qdisc_unlock_tree(dev);

 	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 		goto errout;

 	fh = tp->ops->get(tp, t->tcm_handle);

 	if (fh == 0) {
 		if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 			qdisc_lock_tree(dev);
 			*back = tp->next;
 			qdisc_unlock_tree(dev);

 			tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 			tcf_destroy(tp);
 			err = 0;
 			goto errout;
 		}

 		err = -ENOENT;
 		if (n->nlmsg_type != RTM_NEWTFILTER ||
 		    !(n->nlmsg_flags & NLM_F_CREATE))
 			goto errout;
 	} else {
 		switch (n->nlmsg_type) {
 		case RTM_NEWTFILTER:
 			err = -EEXIST;
 			if (n->nlmsg_flags & NLM_F_EXCL)
 				goto errout;
 			break;
 		case RTM_DELTFILTER:
 			err = tp->ops->delete(tp, fh);
 			if (err == 0)
 				tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 			goto errout;
 		case RTM_GETTFILTER:
 			err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 			goto errout;
 		default:
 			err = -EINVAL;
 			goto errout;
 		}
 	}

 	err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 	if (err == 0)
 		tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);

 errout:
 	if (cl)
 		cops->put(q, cl);
 	if (err == -EAGAIN)
 		/* Replay the request. */
 		goto replay;
 	return err;
 }

 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 			 unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
 {
 	struct tcmsg *tcm;
 	struct nlmsghdr  *nlh;
 	unsigned char *b = skb_tail_pointer(skb);

 	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 	tcm = NLMSG_DATA(nlh);
 	tcm->tcm_family = AF_UNSPEC;
 	tcm->tcm__pad1 = 0;
 	tcm->tcm__pad1 = 0;
 	tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 	tcm->tcm_parent = tp->classid;
 	tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 	NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
 	tcm->tcm_handle = fh;
 	if (RTM_DELTFILTER != event) {
 		tcm->tcm_handle = 0;
 		if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 			goto nla_put_failure;
 	}
 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 	return skb->len;

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

 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 			  struct tcf_proto *tp, unsigned long fh, int event)
 {
 	struct sk_buff *skb;
 	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;

 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (!skb)
 		return -ENOBUFS;

 	if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 		kfree_skb(skb);
 		return -EINVAL;
 	}

 	return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
 			      n->nlmsg_flags & NLM_F_ECHO);
 }

 struct tcf_dump_args {
 	struct tcf_walker w;
 	struct sk_buff *skb;
 	struct netlink_callback *cb;
 };

 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 			 struct tcf_walker *arg)
 {
 	struct tcf_dump_args *a = (void *)arg;

 	return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 			     a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 }

 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net *net = sock_net(skb->sk);
 	struct netdev_queue *dev_queue;
 	int t;
 	int s_t;
 	struct net_device *dev;
 	struct Qdisc *q;
 	struct tcf_proto *tp, **chain;
 	struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
 	unsigned long cl = 0;
 	const struct Qdisc_class_ops *cops;
 	struct tcf_dump_args arg;

 	if (net != &init_net)
 		return 0;

 	if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 		return skb->len;
 	if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 		return skb->len;

 	dev_queue = netdev_get_tx_queue(dev, 0);
 	if (!tcm->tcm_parent)
 		q = dev_queue->qdisc_sleeping;
 	else
 		q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 	if (!q)
 		goto out;
 	if ((cops = q->ops->cl_ops) == NULL)
 		goto errout;
 	if (TC_H_MIN(tcm->tcm_parent)) {
 		cl = cops->get(q, tcm->tcm_parent);
 		if (cl == 0)
 			goto errout;
 	}
 	chain = cops->tcf_chain(q, cl);
 	if (chain == NULL)
 		goto errout;

 	s_t = cb->args[0];

 	for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 		if (t < s_t) continue;
 		if (TC_H_MAJ(tcm->tcm_info) &&
 		    TC_H_MAJ(tcm->tcm_info) != tp->prio)
 			continue;
 		if (TC_H_MIN(tcm->tcm_info) &&
 		    TC_H_MIN(tcm->tcm_info) != tp->protocol)
 			continue;
 		if (t > s_t)
 			memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 		if (cb->args[1] == 0) {
 			if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 					  cb->nlh->nlmsg_seq, NLM_F_MULTI,
 					  RTM_NEWTFILTER) <= 0)
 				break;

 			cb->args[1] = 1;
 		}
 		if (tp->ops->walk == NULL)
 			continue;
 		arg.w.fn = tcf_node_dump;
 		arg.skb = skb;
 		arg.cb = cb;
 		arg.w.stop = 0;
 		arg.w.skip = cb->args[1]-1;
 		arg.w.count = 0;
 		tp->ops->walk(tp, &arg.w);
 		cb->args[1] = arg.w.count+1;
 		if (arg.w.stop)
 			break;
 	}

 	cb->args[0] = t;

 errout:
 	if (cl)
 		cops->put(q, cl);
 out:
 	dev_put(dev);
 	return skb->len;
 }

 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	if (exts->action) {
 		tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 		exts->action = NULL;
 	}
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_destroy);

 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)
 {
 	memset(exts, 0, sizeof(*exts));

 #ifdef CONFIG_NET_CLS_ACT
 	{
 		struct tc_action *act;

 		if (map->police && tb[map->police]) {
 			act = tcf_action_init_1(tb[map->police], rate_tlv,
 						"police", TCA_ACT_NOREPLACE,
 						TCA_ACT_BIND);
 			if (IS_ERR(act))
 				return PTR_ERR(act);

 			act->type = TCA_OLD_COMPAT;
 			exts->action = act;
 		} else if (map->action && tb[map->action]) {
 			act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 					      TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 			if (IS_ERR(act))
 				return PTR_ERR(act);

 			exts->action = act;
 		}
 	}
 #else
 	if ((map->action && tb[map->action]) ||
 	    (map->police && tb[map->police]))
 		return -EOPNOTSUPP;
 #endif

 	return 0;
 }
 EXPORT_SYMBOL(tcf_exts_validate);

 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 		     struct tcf_exts *src)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	if (src->action) {
 		struct tc_action *act;
 		tcf_tree_lock(tp);
 		act = xchg(&dst->action, src->action);
 		tcf_tree_unlock(tp);
 		if (act)
 			tcf_action_destroy(act, TCA_ACT_UNBIND);
 	}
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_change);

 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 		  const struct tcf_ext_map *map)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	if (map->action && exts->action) {
 		/*
 		 * again for backward compatible mode - we want
 		 * to work with both old and new modes of entering
 		 * tc data even if iproute2  was newer - jhs
 		 */
 		struct nlattr *nest;

 		if (exts->action->type != TCA_OLD_COMPAT) {
 			nest = nla_nest_start(skb, map->action);
 			if (nest == NULL)
 				goto nla_put_failure;
 			if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 				goto nla_put_failure;
 			nla_nest_end(skb, nest);
 		} else if (map->police) {
 			nest = nla_nest_start(skb, map->police);
 			if (nest == NULL)
 				goto nla_put_failure;
 			if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 				goto nla_put_failure;
 			nla_nest_end(skb, nest);
 		}
 	}
 #endif
 	return 0;
 nla_put_failure: __attribute__ ((unused))
 	return -1;
 }
 EXPORT_SYMBOL(tcf_exts_dump);


 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 			const struct tcf_ext_map *map)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	if (exts->action)
 		if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 			goto nla_put_failure;
 #endif
 	return 0;
 nla_put_failure: __attribute__ ((unused))
 	return -1;
 }
 EXPORT_SYMBOL(tcf_exts_dump_stats);

 static int __init tc_filter_init(void)
 {
 	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 						 tc_dump_tfilter);

 	return 0;
 }

 subsys_initcall(tc_filter_init);
	/*
	* net/sched/cls_api.c Packet classifier API.
	*
	* 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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	*
	* Changes:
	*
	* Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
	*
	*/

	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/errno.h>
	#include <linux/skbuff.h>
	#include <linux/init.h>
	#include <linux/kmod.h>
	#include <linux/netlink.h>
	#include <linux/err.h>
	#include <net/net_namespace.h>
	#include <net/sock.h>
	#include <net/netlink.h>
	#include <net/pkt_sched.h>
	#include <net/pkt_cls.h>

	/* The list of all installed classifier types */

	static struct tcf_proto_ops *tcf_proto_base __read_mostly;

	/* Protects list of registered TC modules. It is pure SMP lock. */
	static DEFINE_RWLOCK(cls_mod_lock);

	/* Find classifier type by string name */

	static struct tcf_proto_ops tcf_proto_lookup_ops(struct nlattr kind)
	{
	struct tcf_proto_ops *t = NULL;

	if (kind) {
	read_lock(&cls_mod_lock);
	for (t = tcf_proto_base; t; t = t->next) {
	if (nla_strcmp(kind, t->kind) == 0) {
	if (!try_module_get(t->owner))
	t = NULL;
	break;
	}
	}
	read_unlock(&cls_mod_lock);
	}
	return t;
	}

	/* Register(unregister) new classifier type */

	int register_tcf_proto_ops(struct tcf_proto_ops *ops)
	{
	struct tcf_proto_ops t, *tp;
	int rc = -EEXIST;

	write_lock(&cls_mod_lock);
	for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
	if (!strcmp(ops->kind, t->kind))
	goto out;

	ops->next = NULL;
	*tp = ops;
	rc = 0;
	out:
	write_unlock(&cls_mod_lock);
	return rc;
	}
	EXPORT_SYMBOL(register_tcf_proto_ops);

	int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
	{
	struct tcf_proto_ops t, *tp;
	int rc = -ENOENT;

	write_lock(&cls_mod_lock);
	for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
	if (t == ops)
	break;

	if (!t)
	goto out;
	*tp = t->next;
	rc = 0;
	out:
	write_unlock(&cls_mod_lock);
	return rc;
	}
	EXPORT_SYMBOL(unregister_tcf_proto_ops);

	static int tfilter_notify(struct sk_buff oskb, struct nlmsghdr n,
	struct tcf_proto *tp, unsigned long fh, int event);


	/* Select new prio value from the range, managed by kernel. */

	static inline u32 tcf_auto_prio(struct tcf_proto *tp)
	{
	u32 first = TC_H_MAKE(0xC0000000U, 0U);

	if (tp)
	first = tp->prio-1;

	return first;
	}

	/* Add/change/delete/get a filter node */

	static int tc_ctl_tfilter(struct sk_buff skb, struct nlmsghdr n, void *arg)
	{
	struct net *net = sock_net(skb->sk);
	struct nlattr *tca[TCA_MAX + 1];
	struct tcmsg *t;
	u32 protocol;
	u32 prio;
	u32 nprio;
	u32 parent;
	struct net_device *dev;
	struct Qdisc *q;
	struct tcf_proto back, chain;
	struct tcf_proto *tp;
	struct tcf_proto_ops *tp_ops;
	const struct Qdisc_class_ops *cops;
	unsigned long cl;
	unsigned long fh;
	int err;

	if (net != &init_net)
	return -EINVAL;

	replay:
	t = NLMSG_DATA(n);
	protocol = TC_H_MIN(t->tcm_info);
	prio = TC_H_MAJ(t->tcm_info);
	nprio = prio;
	parent = t->tcm_parent;
	cl = 0;

	if (prio == 0) {
	/* If no priority is given, user wants we allocated it. */
	if (n->nlmsg_type != RTM_NEWTFILTER \|\| !(n->nlmsg_flags&NLM_F_CREATE))
	return -ENOENT;
	prio = TC_H_MAKE(0x80000000U, 0U);
	}

	/* Find head of filter chain. */

	/* Find link */
	dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
	if (dev == NULL)
	return -ENODEV;

	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
	if (err < 0)
	return err;

	/* Find qdisc */
	if (!parent) {
	struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
	q = dev_queue->qdisc_sleeping;
	parent = q->handle;
	} else {
	q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
	if (q == NULL)
	return -EINVAL;
	}

	/* Is it classful? */
	if ((cops = q->ops->cl_ops) == NULL)
	return -EINVAL;

	/* Do we search for filter, attached to class? */
	if (TC_H_MIN(parent)) {
	cl = cops->get(q, parent);
	if (cl == 0)
	return -ENOENT;
	}

	/* And the last stroke */
	chain = cops->tcf_chain(q, cl);
	err = -EINVAL;
	if (chain == NULL)
	goto errout;

	/* Check the chain for existence of proto-tcf with this priority */
	for (back = chain; (tp=*back) != NULL; back = &tp->next) {
	if (tp->prio >= prio) {
	if (tp->prio == prio) {
	if (!nprio \|\| (tp->protocol != protocol && protocol))
	goto errout;
	} else
	tp = NULL;
	break;
	}
	}

	if (tp == NULL) {
	/* Proto-tcf does not exist, create new one */

	if (tca[TCA_KIND] == NULL \|\| !protocol)
	goto errout;

	err = -ENOENT;
	if (n->nlmsg_type != RTM_NEWTFILTER \|\| !(n->nlmsg_flags&NLM_F_CREATE))
	goto errout;


	/* Create new proto tcf */

	err = -ENOBUFS;
	tp = kzalloc(sizeof(*tp), GFP_KERNEL);
	if (tp == NULL)
	goto errout;
	err = -ENOENT;
	tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
	if (tp_ops == NULL) {
	#ifdef CONFIG_KMOD
	struct nlattr *kind = tca[TCA_KIND];
	char name[IFNAMSIZ];

	if (kind != NULL &&
	nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
	rtnl_unlock();
	request_module("cls_%s", name);
	rtnl_lock();
	tp_ops = tcf_proto_lookup_ops(kind);
	/* We dropped the RTNL semaphore in order to
	* perform the module load. So, even if we
	* succeeded in loading the module we have to
	* replay the request. We indicate this using
	* -EAGAIN.
	*/
	if (tp_ops != NULL) {
	module_put(tp_ops->owner);
	err = -EAGAIN;
	}
	}
	#endif
	kfree(tp);
	goto errout;
	}
	tp->ops = tp_ops;
	tp->protocol = protocol;
	tp->prio = nprio ? : tcf_auto_prio(*back);
	tp->q = q;
	tp->classify = tp_ops->classify;
	tp->classid = parent;

	err = tp_ops->init(tp);
	if (err != 0) {
	module_put(tp_ops->owner);
	kfree(tp);
	goto errout;
	}

	qdisc_lock_tree(dev);
	tp->next = *back;
	*back = tp;
	qdisc_unlock_tree(dev);

	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
	goto errout;

	fh = tp->ops->get(tp, t->tcm_handle);

	if (fh == 0) {
	if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
	qdisc_lock_tree(dev);
	*back = tp->next;
	qdisc_unlock_tree(dev);

	tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
	tcf_destroy(tp);
	err = 0;
	goto errout;
	}

	err = -ENOENT;
	if (n->nlmsg_type != RTM_NEWTFILTER \|\|
	!(n->nlmsg_flags & NLM_F_CREATE))
	goto errout;
	} else {
	switch (n->nlmsg_type) {
	case RTM_NEWTFILTER:
	err = -EEXIST;
	if (n->nlmsg_flags & NLM_F_EXCL)
	goto errout;
	break;
	case RTM_DELTFILTER:
	err = tp->ops->delete(tp, fh);
	if (err == 0)
	tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
	goto errout;
	case RTM_GETTFILTER:
	err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
	goto errout;
	default:
	err = -EINVAL;
	goto errout;
	}
	}

	err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
	if (err == 0)
	tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);

	errout:
	if (cl)
	cops->put(q, cl);
	if (err == -EAGAIN)
	/* Replay the request. */
	goto replay;
	return err;
	}

	static int tcf_fill_node(struct sk_buff skb, struct tcf_proto tp,
	unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
	{
	struct tcmsg *tcm;
	struct nlmsghdr *nlh;
	unsigned char *b = skb_tail_pointer(skb);

	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
	tcm = NLMSG_DATA(nlh);
	tcm->tcm_family = AF_UNSPEC;
	tcm->tcm__pad1 = 0;
	tcm->tcm__pad1 = 0;
	tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
	tcm->tcm_parent = tp->classid;
	tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
	NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
	tcm->tcm_handle = fh;
	if (RTM_DELTFILTER != event) {
	tcm->tcm_handle = 0;
	if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
	goto nla_put_failure;
	}
	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	return skb->len;

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

	static int tfilter_notify(struct sk_buff oskb, struct nlmsghdr n,
	struct tcf_proto *tp, unsigned long fh, int event)
	{
	struct sk_buff *skb;
	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
	return -ENOBUFS;

	if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
	kfree_skb(skb);
	return -EINVAL;
	}

	return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
	n->nlmsg_flags & NLM_F_ECHO);
	}

	struct tcf_dump_args {
	struct tcf_walker w;
	struct sk_buff *skb;
	struct netlink_callback *cb;
	};

	static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
	struct tcf_walker *arg)
	{
	struct tcf_dump_args a = (void )arg;

	return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
	a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
	}

	static int tc_dump_tfilter(struct sk_buff skb, struct netlink_callback cb)
	{
	struct net *net = sock_net(skb->sk);
	struct netdev_queue *dev_queue;
	int t;
	int s_t;
	struct net_device *dev;
	struct Qdisc *q;
	struct tcf_proto tp, *chain;
	struct tcmsg tcm = (struct tcmsg )NLMSG_DATA(cb->nlh);
	unsigned long cl = 0;
	const struct Qdisc_class_ops *cops;
	struct tcf_dump_args arg;

	if (net != &init_net)
	return 0;

	if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
	return skb->len;
	if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
	return skb->len;

	dev_queue = netdev_get_tx_queue(dev, 0);
	if (!tcm->tcm_parent)
	q = dev_queue->qdisc_sleeping;
	else
	q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
	if (!q)
	goto out;
	if ((cops = q->ops->cl_ops) == NULL)
	goto errout;
	if (TC_H_MIN(tcm->tcm_parent)) {
	cl = cops->get(q, tcm->tcm_parent);
	if (cl == 0)
	goto errout;
	}
	chain = cops->tcf_chain(q, cl);
	if (chain == NULL)
	goto errout;

	s_t = cb->args[0];

	for (tp=*chain, t=0; tp; tp = tp->next, t++) {
	if (t < s_t) continue;
	if (TC_H_MAJ(tcm->tcm_info) &&
	TC_H_MAJ(tcm->tcm_info) != tp->prio)
	continue;
	if (TC_H_MIN(tcm->tcm_info) &&
	TC_H_MIN(tcm->tcm_info) != tp->protocol)
	continue;
	if (t > s_t)
	memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
	if (cb->args[1] == 0) {
	if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
	cb->nlh->nlmsg_seq, NLM_F_MULTI,
	RTM_NEWTFILTER) <= 0)
	break;

	cb->args[1] = 1;
	}
	if (tp->ops->walk == NULL)
	continue;
	arg.w.fn = tcf_node_dump;
	arg.skb = skb;
	arg.cb = cb;
	arg.w.stop = 0;
	arg.w.skip = cb->args[1]-1;
	arg.w.count = 0;
	tp->ops->walk(tp, &arg.w);
	cb->args[1] = arg.w.count+1;
	if (arg.w.stop)
	break;
	}

	cb->args[0] = t;

	errout:
	if (cl)
	cops->put(q, cl);
	out:
	dev_put(dev);
	return skb->len;
	}

	void tcf_exts_destroy(struct tcf_proto tp, struct tcf_exts exts)
	{
	#ifdef CONFIG_NET_CLS_ACT
	if (exts->action) {
	tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
	exts->action = NULL;
	}
	#endif
	}
	EXPORT_SYMBOL(tcf_exts_destroy);

	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)
	{
	memset(exts, 0, sizeof(*exts));

	#ifdef CONFIG_NET_CLS_ACT
	{
	struct tc_action *act;

	if (map->police && tb[map->police]) {
	act = tcf_action_init_1(tb[map->police], rate_tlv,
	"police", TCA_ACT_NOREPLACE,
	TCA_ACT_BIND);
	if (IS_ERR(act))
	return PTR_ERR(act);

	act->type = TCA_OLD_COMPAT;
	exts->action = act;
	} else if (map->action && tb[map->action]) {
	act = tcf_action_init(tb[map->action], rate_tlv, NULL,
	TCA_ACT_NOREPLACE, TCA_ACT_BIND);
	if (IS_ERR(act))
	return PTR_ERR(act);

	exts->action = act;
	}
	}
	#else
	if ((map->action && tb[map->action]) \|\|
	(map->police && tb[map->police]))
	return -EOPNOTSUPP;
	#endif

	return 0;
	}
	EXPORT_SYMBOL(tcf_exts_validate);

	void tcf_exts_change(struct tcf_proto tp, struct tcf_exts dst,
	struct tcf_exts *src)
	{
	#ifdef CONFIG_NET_CLS_ACT
	if (src->action) {
	struct tc_action *act;
	tcf_tree_lock(tp);
	act = xchg(&dst->action, src->action);
	tcf_tree_unlock(tp);
	if (act)
	tcf_action_destroy(act, TCA_ACT_UNBIND);
	}
	#endif
	}
	EXPORT_SYMBOL(tcf_exts_change);

	int tcf_exts_dump(struct sk_buff skb, struct tcf_exts exts,
	const struct tcf_ext_map *map)
	{
	#ifdef CONFIG_NET_CLS_ACT
	if (map->action && exts->action) {
	/*
	* again for backward compatible mode - we want
	* to work with both old and new modes of entering
	* tc data even if iproute2 was newer - jhs
	*/
	struct nlattr *nest;

	if (exts->action->type != TCA_OLD_COMPAT) {
	nest = nla_nest_start(skb, map->action);
	if (nest == NULL)
	goto nla_put_failure;
	if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
	goto nla_put_failure;
	nla_nest_end(skb, nest);
	} else if (map->police) {
	nest = nla_nest_start(skb, map->police);
	if (nest == NULL)
	goto nla_put_failure;
	if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
	goto nla_put_failure;
	nla_nest_end(skb, nest);
	}
	}
	#endif
	return 0;
	nla_put_failure: __attribute__ ((unused))
	return -1;
	}
	EXPORT_SYMBOL(tcf_exts_dump);


	int tcf_exts_dump_stats(struct sk_buff skb, struct tcf_exts exts,
	const struct tcf_ext_map *map)
	{
	#ifdef CONFIG_NET_CLS_ACT
	if (exts->action)
	if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
	goto nla_put_failure;
	#endif
	return 0;
	nla_put_failure: __attribute__ ((unused))
	return -1;
	}
	EXPORT_SYMBOL(tcf_exts_dump_stats);

	static int __init tc_filter_init(void)
	{
	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
	tc_dump_tfilter);

	return 0;
	}

	subsys_initcall(tc_filter_init);