/*
 * net/sched/cls_route.c	ROUTE4 classifier.
 *
 *		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>
 */

#include <linux/module.h>
#include <linux/config.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/pkt_sched.h>


struct route4_fastmap
{
	struct route4_filter	*filter;
	u32			id;
	int			iif;
};

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

struct route4_bucket
{
	struct route4_filter	*ht[16+16+1];
};

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

	struct tcf_result	res;
#ifdef CONFIG_NET_CLS_POLICE
	struct tcf_police	*police;
#endif

	u32			handle;
	struct route4_bucket	*bkt;
};

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

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

static void route4_reset_fastmap(struct net_device *dev, struct route4_head *head, u32 id)
{
	spin_lock_bh(&dev->queue_lock);
	memset(head->fastmap, 0, sizeof(head->fastmap));
	spin_unlock_bh(&dev->queue_lock);
}

static void __inline__
route4_set_fastmap(struct route4_head *head, u32 id, int iif,
		   struct route4_filter *f)
{
	int h = route4_fastmap_hash(id, iif);
	head->fastmap[h].id = id;
	head->fastmap[h].iif = iif;
	head->fastmap[h].filter = f;
}

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;
}

#ifdef CONFIG_NET_CLS_POLICE
#define IF_ROUTE_POLICE \
if (f->police) { \
	int pol_res = tcf_police(skb, f->police); \
	if (pol_res >= 0) return pol_res; \
	dont_cache = 1; \
	continue; \
} \
if (!dont_cache)
#else
#define IF_ROUTE_POLICE
#endif


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

	if ((dst = skb->dst) == NULL)
		goto failure;

	id = dst->tclassid;
	if (head == NULL)
		goto old_method;

	iif = ((struct rtable*)dst)->key.iif;

	h = route4_fastmap_hash(id, iif);
	if (id == head->fastmap[h].id &&
	    iif == head->fastmap[h].iif &&
	    (f = head->fastmap[h].filter) != NULL) {
		if (f == ROUTE4_FAILURE)
			goto failure;

		*res = f->res;
		return 0;
	}

	h = route4_hash_to(id);

restart:
	if ((b = head->table[h]) != NULL) {
		f = b->ht[route4_hash_from(id)];

		for ( ; f; f = f->next) {
			if (f->id == id) {
				*res = f->res;
				IF_ROUTE_POLICE route4_set_fastmap(head, id, iif, f);
				return 0;
			}
		}

		for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next) {
			if (f->iif == iif) {
				*res = f->res;
				IF_ROUTE_POLICE route4_set_fastmap(head, id, iif, f);
				return 0;
			}
		}

		for (f = b->ht[route4_hash_wild()]; f; f = f->next) {
			*res = f->res;
			IF_ROUTE_POLICE route4_set_fastmap(head, id, iif, f);
			return 0;
		}

	}
	if (h < 256) {
		h = 256;
		id &= ~0xFFFF;
		goto restart;
	}

#ifdef CONFIG_NET_CLS_POLICE
	if (!dont_cache)
#endif
		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
failure:
	return -1;

old_method:
	if (id && (TC_H_MAJ(id) == 0 ||
		   !(TC_H_MAJ(id^tp->q->handle)))) {
		res->classid = id;
		res->class = 0;
		return 0;
	}
	return -1;
}

static u32 to_hash(u32 id)
{
	u32 h = id&0xFF;
	if (id&0x8000)
		h += 256;
	return h;
}

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

	if (!head)
		return 0;

	h1 = to_hash(handle);
	if (h1 > 256)
		return 0;

	h2 = from_hash(handle>>16);
	if (h2 > 32)
		return 0;

	if ((b = head->table[h1]) != NULL) {
		for (f = b->ht[h2]; f; f = f->next)
			if (f->handle == handle)
				return (unsigned long)f;
	}
	return 0;
}

static void route4_put(struct tcf_proto *tp, unsigned long f)
{
}

static int route4_init(struct tcf_proto *tp)
{
	MOD_INC_USE_COUNT;
	return 0;
}

static void route4_destroy(struct tcf_proto *tp)
{
	struct route4_head *head = xchg(&tp->root, NULL);
	int h1, h2;

	if (head == NULL) {
		MOD_DEC_USE_COUNT;
		return;
	}

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

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

				while ((f = b->ht[h2]) != NULL) {
					unsigned long cl;

					b->ht[h2] = f->next;
					if ((cl = __cls_set_class(&f->res.class, 0)) != 0)
						tp->q->ops->cl_ops->unbind_tcf(tp->q, cl);
#ifdef CONFIG_NET_CLS_POLICE
					tcf_police_release(f->police);
#endif
					kfree(f);
				}
			}
			kfree(b);
		}
	}
	kfree(head);
	MOD_DEC_USE_COUNT;
}

static int route4_delete(struct tcf_proto *tp, unsigned long arg)
{
	struct route4_head *head = (struct route4_head*)tp->root;
	struct route4_filter **fp, *f = (struct route4_filter*)arg;
	unsigned h = 0;
	struct route4_bucket *b;
	int i;

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

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

	for (fp = &b->ht[from_hash(h>>16)]; *fp; fp = &(*fp)->next) {
		if (*fp == f) {
			unsigned long cl;

			tcf_tree_lock(tp);
			*fp = f->next;
			tcf_tree_unlock(tp);

			route4_reset_fastmap(tp->q->dev, head, f->id);

			if ((cl = cls_set_class(tp, &f->res.class, 0)) != 0)
				tp->q->ops->cl_ops->unbind_tcf(tp->q, cl);

#ifdef CONFIG_NET_CLS_POLICE
			tcf_police_release(f->police);
#endif
			kfree(f);

			/* Strip tree */

			for (i=0; i<=32; i++)
				if (b->ht[i])
					return 0;

			/* OK, session has no flows */
			tcf_tree_lock(tp);
			head->table[to_hash(h)] = NULL;
			tcf_tree_unlock(tp);

			kfree(b);
			return 0;
		}
	}
	return 0;
}

static int route4_change(struct tcf_proto *tp, unsigned long base,
		       u32 handle,
		       struct rtattr **tca,
		       unsigned long *arg)
{
	struct route4_head *head = tp->root;
	struct route4_filter *f, *f1, **ins_f;
	struct route4_bucket *b;
	struct rtattr *opt = tca[TCA_OPTIONS-1];
	struct rtattr *tb[TCA_ROUTE4_MAX];
	unsigned h1, h2;
	int err;

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

	if (rtattr_parse(tb, TCA_ROUTE4_MAX, RTA_DATA(opt), RTA_PAYLOAD(opt)) < 0)
		return -EINVAL;

	if ((f = (struct route4_filter*)*arg) != NULL) {
		/* Node exists: adjust only classid */

		if (f->handle != handle && handle)
			return -EINVAL;
		if (tb[TCA_ROUTE4_CLASSID-1]) {
			unsigned long cl;

			f->res.classid = *(u32*)RTA_DATA(tb[TCA_ROUTE4_CLASSID-1]);
			cl = cls_set_class(tp, &f->res.class, tp->q->ops->cl_ops->bind_tcf(tp->q, base, f->res.classid));
			if (cl)
				tp->q->ops->cl_ops->unbind_tcf(tp->q, cl);
		}
#ifdef CONFIG_NET_CLS_POLICE
		if (tb[TCA_ROUTE4_POLICE-1]) {
			struct tcf_police *police = tcf_police_locate(tb[TCA_ROUTE4_POLICE-1], tca[TCA_RATE-1]);

			tcf_tree_lock(tp);
			police = xchg(&f->police, police);
			tcf_tree_unlock(tp);

			tcf_police_release(police);
		}
#endif
		return 0;
	}

	/* Now more serious part... */

	if (head == NULL) {
		head = kmalloc(sizeof(struct route4_head), GFP_KERNEL);
		if (head == NULL)
			return -ENOBUFS;
		memset(head, 0, sizeof(struct route4_head));

		tcf_tree_lock(tp);
		tp->root = head;
		tcf_tree_unlock(tp);
	}

	f = kmalloc(sizeof(struct route4_filter), GFP_KERNEL);
	if (f == NULL)
		return -ENOBUFS;

	memset(f, 0, sizeof(*f));

	err = -EINVAL;
	f->handle = 0x8000;
	if (tb[TCA_ROUTE4_TO-1]) {
		if (handle&0x8000)
			goto errout;
		if (RTA_PAYLOAD(tb[TCA_ROUTE4_TO-1]) < 4)
			goto errout;
		f->id = *(u32*)RTA_DATA(tb[TCA_ROUTE4_TO-1]);
		if (f->id > 0xFF)
			goto errout;
		f->handle = f->id;
	}
	if (tb[TCA_ROUTE4_FROM-1]) {
		u32 sid;
		if (tb[TCA_ROUTE4_IIF-1])
			goto errout;
		if (RTA_PAYLOAD(tb[TCA_ROUTE4_FROM-1]) < 4)
			goto errout;
		sid = (*(u32*)RTA_DATA(tb[TCA_ROUTE4_FROM-1]));
		if (sid > 0xFF)
			goto errout;
		f->handle |= sid<<16;
		f->id |= sid<<16;
	} else if (tb[TCA_ROUTE4_IIF-1]) {
		if (RTA_PAYLOAD(tb[TCA_ROUTE4_IIF-1]) < 4)
			goto errout;
		f->iif = *(u32*)RTA_DATA(tb[TCA_ROUTE4_IIF-1]);
		if (f->iif > 0x7FFF)
			goto errout;
		f->handle |= (f->iif|0x8000)<<16;
	} else
		f->handle |= 0xFFFF<<16;

	if (handle) {
		f->handle |= handle&0x7F00;
		if (f->handle != handle)
			goto errout;
	}

	if (tb[TCA_ROUTE4_CLASSID-1]) {
		if (RTA_PAYLOAD(tb[TCA_ROUTE4_CLASSID-1]) < 4)
			goto errout;
		f->res.classid = *(u32*)RTA_DATA(tb[TCA_ROUTE4_CLASSID-1]);
	}

	h1 = to_hash(f->handle);
	if ((b = head->table[h1]) == NULL) {
		err = -ENOBUFS;
		b = kmalloc(sizeof(struct route4_bucket), GFP_KERNEL);
		if (b == NULL)
			goto errout;
		memset(b, 0, sizeof(*b));

		tcf_tree_lock(tp);
		head->table[h1] = b;
		tcf_tree_unlock(tp);
	}
	f->bkt = b;

	err = -EEXIST;
	h2 = from_hash(f->handle>>16);
	for (ins_f = &b->ht[h2]; (f1=*ins_f) != NULL; ins_f = &f1->next) {
		if (f->handle < f1->handle)
			break;
		if (f1->handle == f->handle)
			goto errout;
	}

	cls_set_class(tp, &f->res.class, tp->q->ops->cl_ops->bind_tcf(tp->q, base, f->res.classid));
#ifdef CONFIG_NET_CLS_POLICE
	if (tb[TCA_ROUTE4_POLICE-1])
		f->police = tcf_police_locate(tb[TCA_ROUTE4_POLICE-1], tca[TCA_RATE-1]);
#endif

	f->next = f1;
	tcf_tree_lock(tp);
	*ins_f = f;
	tcf_tree_unlock(tp);

	route4_reset_fastmap(tp->q->dev, head, f->id);
	*arg = (unsigned long)f;
	return 0;

errout:
	if (f)
		kfree(f);
	return err;
}

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

	if (head == NULL)
		arg->stop = 1;

	if (arg->stop)
		return;

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

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

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

static int route4_dump(struct tcf_proto *tp, unsigned long fh,
		       struct sk_buff *skb, struct tcmsg *t)
{
	struct route4_filter *f = (struct route4_filter*)fh;
	unsigned char	 *b = skb->tail;
	struct rtattr *rta;
	u32 id;

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

	t->tcm_handle = f->handle;

	rta = (struct rtattr*)b;
	RTA_PUT(skb, TCA_OPTIONS, 0, NULL);

	if (!(f->handle&0x8000)) {
		id = f->id&0xFF;
		RTA_PUT(skb, TCA_ROUTE4_TO, sizeof(id), &id);
	}
	if (f->handle&0x80000000) {
		if ((f->handle>>16) != 0xFFFF)
			RTA_PUT(skb, TCA_ROUTE4_IIF, sizeof(f->iif), &f->iif);
	} else {
		id = f->id>>16;
		RTA_PUT(skb, TCA_ROUTE4_FROM, sizeof(id), &id);
	}
	if (f->res.classid)
		RTA_PUT(skb, TCA_ROUTE4_CLASSID, 4, &f->res.classid);
#ifdef CONFIG_NET_CLS_POLICE
	if (f->police) {
		struct rtattr * p_rta = (struct rtattr*)skb->tail;

		RTA_PUT(skb, TCA_ROUTE4_POLICE, 0, NULL);

		if (tcf_police_dump(skb, f->police) < 0)
			goto rtattr_failure;

		p_rta->rta_len = skb->tail - (u8*)p_rta;
	}
#endif

	rta->rta_len = skb->tail - b;
#ifdef CONFIG_NET_CLS_POLICE
	if (f->police) {
		if (qdisc_copy_stats(skb, &f->police->stats))
			goto rtattr_failure;
	}
#endif
	return skb->len;

rtattr_failure:
	skb_trim(skb, b - skb->data);
	return -1;
}

struct tcf_proto_ops cls_route4_ops = {
	NULL,
	"route",
	route4_classify,
	route4_init,
	route4_destroy,

	route4_get,
	route4_put,
	route4_change,
	route4_delete,
	route4_walk,
	route4_dump
};

#ifdef MODULE
int init_module(void)
{
	return register_tcf_proto_ops(&cls_route4_ops);
}

void cleanup_module(void)
{
	unregister_tcf_proto_ops(&cls_route4_ops);
}
#endif
MODULE_LICENSE("GPL");