/*

 * 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];

	spinlock_t *root_lock;

	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;

		}

	}

	root_lock = qdisc_root_sleeping_lock(q);

	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_MODULES

			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;

		}

		spin_lock_bh(root_lock);

		tp->next = *back;

		*back = tp;

		spin_unlock_bh(root_lock);

	} 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) {

			spin_lock_bh(root_lock);

			*back = tp->next;

			spin_unlock_bh(root_lock);

			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)

{