openwrt-xburst/target/linux/generic-2.6/patches-2.6.27/200-sched_esfq.patch

--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -173,8 +173,37 @@
  *
  *	The only reason for this is efficiency, it is possible
  *	to change these parameters in compile time.
+ *
+ *	If you need to play with these values, use esfq instead.
  */
 
+/* ESFQ section */
+
+enum
+{
+        /* traditional */
+	TCA_SFQ_HASH_CLASSIC,
+	TCA_SFQ_HASH_DST,
+	TCA_SFQ_HASH_SRC,
+	TCA_SFQ_HASH_FWMARK,
+	/* conntrack */
+	TCA_SFQ_HASH_CTORIGDST,
+	TCA_SFQ_HASH_CTORIGSRC,
+	TCA_SFQ_HASH_CTREPLDST,
+	TCA_SFQ_HASH_CTREPLSRC,
+	TCA_SFQ_HASH_CTNATCHG,
+};
+
+struct tc_esfq_qopt
+{
+	unsigned	quantum;	/* Bytes per round allocated to flow */
+	int		perturb_period;	/* Period of hash perturbation */
+	__u32		limit;		/* Maximal packets in queue */
+	unsigned	divisor;	/* Hash divisor  */
+	unsigned	flows;		/* Maximal number of flows  */
+	unsigned	hash_kind;	/* Hash function to use for flow identification */
+};
+
 /* RED section */
 
 enum
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -128,6 +128,37 @@
 	  To compile this code as a module, choose M here: the
 	  module will be called sch_sfq.
 
+config NET_SCH_ESFQ
+	tristate "Enhanced Stochastic Fairness Queueing (ESFQ)"
+	---help---
+	  Say Y here if you want to use the Enhanced Stochastic Fairness
+	  Queueing (ESFQ) packet scheduling algorithm for some of your network
+	  devices or as a leaf discipline for a classful qdisc such as HTB or
+	  CBQ (see the top of <file:net/sched/sch_esfq.c> for details and
+	  references to the SFQ algorithm).
+
+	  This is an enchanced SFQ version which allows you to control some
+	  hardcoded values in the SFQ scheduler.
+
+	  ESFQ also adds control of the hash function used to identify packet
+	  flows. The original SFQ discipline hashes by connection; ESFQ add
+	  several other hashing methods, such as by src IP or by dst IP, which
+	  can be more fair to users in some networking situations.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called sch_esfq.
+
+config NET_SCH_ESFQ_NFCT
+	bool "Connection Tracking Hash Types"
+	depends on NET_SCH_ESFQ && NF_CONNTRACK
+	---help---
+	  Say Y here to enable support for hashing based on netfilter connection
+	  tracking information. This is useful for a router that is also using
+	  NAT to connect privately-addressed hosts to the Internet. If you want
+	  to provide fair distribution of upstream bandwidth, ESFQ must use
+	  connection tracking information, since all outgoing packets will share
+	  the same source address.
+
 config NET_SCH_TEQL
 	tristate "True Link Equalizer (TEQL)"
 	---help---
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -23,6 +23,7 @@
 obj-$(CONFIG_NET_SCH_INGRESS)	+= sch_ingress.o 
 obj-$(CONFIG_NET_SCH_DSMARK)	+= sch_dsmark.o
 obj-$(CONFIG_NET_SCH_SFQ)	+= sch_sfq.o
+obj-$(CONFIG_NET_SCH_ESFQ)	+= sch_esfq.o
 obj-$(CONFIG_NET_SCH_TBF)	+= sch_tbf.o
 obj-$(CONFIG_NET_SCH_TEQL)	+= sch_teql.o
 obj-$(CONFIG_NET_SCH_PRIO)	+= sch_prio.o
--- /dev/null
+++ b/net/sched/sch_esfq.c
@@ -0,0 +1,702 @@
+/*
+ * net/sched/sch_esfq.c	Extended Stochastic Fairness Queueing discipline.
+ *
+ *		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:	Alexander Atanasov, <alex@ssi.bg>
+ *		Added dynamic depth,limit,divisor,hash_kind options.
+ *		Added dst and src hashes.
+ *
+ * 		Alexander Clouter, <alex@digriz.org.uk>
+ *		Ported ESFQ to Linux 2.6.
+ *
+ * 		Corey Hickey, <bugfood-c@fatooh.org>
+ *		Maintenance of the Linux 2.6 port.
+ *		Added fwmark hash (thanks to Robert Kurjata).
+ *		Added usage of jhash.
+ *		Added conntrack support.
+ *		Added ctnatchg hash (thanks to Ben Pfountz).
+ */
+
+#include <linux/module.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.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 <linux/init.h>
+#include <net/ip.h>
+#include <linux/ipv6.h>
+#include <net/route.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/pkt_sched.h>
+#include <linux/jhash.h>
+#include <net/netfilter/nf_conntrack.h>
+
+/*	Stochastic Fairness Queuing algorithm.
+	For more comments look at sch_sfq.c.
+	The difference is that you can change limit, depth,
+	hash table size and choose alternate hash types.
+
+	classic:	same as in sch_sfq.c
+	dst:		destination IP address
+	src:		source IP address
+	fwmark:		netfilter mark value
+	ctorigdst:	original destination IP address
+	ctorigsrc:	original source IP address
+	ctrepldst:	reply destination IP address
+	ctreplsrc:	reply source IP
+
+*/
+
+#define ESFQ_HEAD 0
+#define ESFQ_TAIL 1
+
+/* This type should contain at least SFQ_DEPTH*2 values */
+typedef unsigned int esfq_index;
+
+struct esfq_head
+{
+	esfq_index	next;
+	esfq_index	prev;
+};
+
+struct esfq_sched_data
+{
+/* Parameters */
+	int		perturb_period;
+	unsigned	quantum;	/* Allotment per round: MUST BE >= MTU */
+	int		limit;
+	unsigned	depth;
+	unsigned	hash_divisor;
+	unsigned	hash_kind;
+/* Variables */
+	struct timer_list perturb_timer;
+	int		perturbation;
+	esfq_index	tail;		/* Index of current slot in round */
+	esfq_index	max_depth;	/* Maximal depth */
+
+	esfq_index	*ht;			/* Hash table */
+	esfq_index	*next;			/* Active slots link */
+	short		*allot;			/* Current allotment per slot */
+	unsigned short	*hash;			/* Hash value indexed by slots */
+	struct sk_buff_head	*qs;		/* Slot queue */
+	struct esfq_head	*dep;		/* Linked list of slots, indexed by depth */
+};
+
+/* This contains the info we will hash. */
+struct esfq_packet_info
+{
+	u32	proto;		/* protocol or port */
+	u32	src;		/* source from packet header */
+	u32	dst;		/* destination from packet header */
+	u32	ctorigsrc;	/* original source from conntrack */
+	u32	ctorigdst;	/* original destination from conntrack */
+	u32	ctreplsrc;	/* reply source from conntrack */
+	u32	ctrepldst;	/* reply destination from conntrack */
+	u32	mark;		/* netfilter mark (fwmark) */
+};
+
+static __inline__ unsigned esfq_jhash_1word(struct esfq_sched_data *q,u32 a)
+{
+	return jhash_1word(a, q->perturbation) & (q->hash_divisor-1);
+}
+
+static __inline__ unsigned esfq_jhash_2words(struct esfq_sched_data *q, u32 a, u32 b)
+{
+	return jhash_2words(a, b, q->perturbation) & (q->hash_divisor-1);
+}
+
+static __inline__ unsigned esfq_jhash_3words(struct esfq_sched_data *q, u32 a, u32 b, u32 c)
+{
+	return jhash_3words(a, b, c, q->perturbation) & (q->hash_divisor-1);
+}
+
+static unsigned esfq_hash(struct esfq_sched_data *q, struct sk_buff *skb)
+{
+	struct esfq_packet_info info;
+#ifdef CONFIG_NET_SCH_ESFQ_NFCT
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+#endif
+
+	switch (skb->protocol) {
+	case __constant_htons(ETH_P_IP):
+	{
+		struct iphdr *iph = ip_hdr(skb);
+		info.dst = iph->daddr;
+		info.src = iph->saddr;
+		if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
+		    (iph->protocol == IPPROTO_TCP ||
+		     iph->protocol == IPPROTO_UDP ||
+		     iph->protocol == IPPROTO_SCTP ||
+		     iph->protocol == IPPROTO_DCCP ||
+		     iph->protocol == IPPROTO_ESP))
+			info.proto = *(((u32*)iph) + iph->ihl);
+		else
+			info.proto = iph->protocol;
+		break;
+	}
+	case __constant_htons(ETH_P_IPV6):
+	{
+		struct ipv6hdr *iph = ipv6_hdr(skb);
+		/* Hash ipv6 addresses into a u32. This isn't ideal,
+		 * but the code is simple. */
+		info.dst = jhash2(iph->daddr.s6_addr32, 4, q->perturbation);
+		info.src = jhash2(iph->saddr.s6_addr32, 4, q->perturbation);
+		if (iph->nexthdr == IPPROTO_TCP ||
+		    iph->nexthdr == IPPROTO_UDP ||
+		    iph->nexthdr == IPPROTO_SCTP ||
+		    iph->nexthdr == IPPROTO_DCCP ||
+		    iph->nexthdr == IPPROTO_ESP)
+			info.proto = *(u32*)&iph[1];
+		else
+			info.proto = iph->nexthdr;
+		break;
+	}
+	default:
+		info.dst   = (u32)(unsigned long)skb->dst;
+		info.src   = (u32)(unsigned long)skb->sk;
+		info.proto = skb->protocol;
+	}
+
+	info.mark = skb->mark;
+
+#ifdef CONFIG_NET_SCH_ESFQ_NFCT
+	/* defaults if there is no conntrack info */
+	info.ctorigsrc = info.src;
+	info.ctorigdst = info.dst;
+	info.ctreplsrc = info.dst;
+	info.ctrepldst = info.src;
+	/* collect conntrack info */
+	if (ct && ct != &nf_conntrack_untracked) {
+		if (skb->protocol == __constant_htons(ETH_P_IP)) {
+			info.ctorigsrc = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
+			info.ctorigdst = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip;
+			info.ctreplsrc = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip;
+			info.ctrepldst = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
+		}
+		else if (skb->protocol == __constant_htons(ETH_P_IPV6)) {
+			/* Again, hash ipv6 addresses into a single u32. */
+			info.ctorigsrc = jhash2(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip6, 4, q->perturbation);
+			info.ctorigdst = jhash2(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip6, 4, q->perturbation);
+			info.ctreplsrc = jhash2(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip6, 4, q->perturbation);
+			info.ctrepldst = jhash2(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip6, 4, q->perturbation);
+		}
+
+	}
+#endif
+
+	switch(q->hash_kind) {
+	case TCA_SFQ_HASH_CLASSIC:
+		return esfq_jhash_3words(q, info.dst, info.src, info.proto);
+	case TCA_SFQ_HASH_DST:
+		return esfq_jhash_1word(q, info.dst);
+	case TCA_SFQ_HASH_SRC:
+		return esfq_jhash_1word(q, info.src);
+	case TCA_SFQ_HASH_FWMARK:
+		return esfq_jhash_1word(q, info.mark);
+#ifdef CONFIG_NET_SCH_ESFQ_NFCT
+	case TCA_SFQ_HASH_CTORIGDST:
+		return esfq_jhash_1word(q, info.ctorigdst);
+	case TCA_SFQ_HASH_CTORIGSRC:
+		return esfq_jhash_1word(q, info.ctorigsrc);
+	case TCA_SFQ_HASH_CTREPLDST:
+		return esfq_jhash_1word(q, info.ctrepldst);
+	case TCA_SFQ_HASH_CTREPLSRC:
+		return esfq_jhash_1word(q, info.ctreplsrc);
+	case TCA_SFQ_HASH_CTNATCHG:
+	{
+		if (info.ctorigdst == info.ctreplsrc)
+			return esfq_jhash_1word(q, info.ctorigsrc);
+		return esfq_jhash_1word(q, info.ctreplsrc);
+	}
+#endif
+	default:
+		if (net_ratelimit())
+			printk(KERN_WARNING "ESFQ: Unknown hash method. Falling back to classic.\n");
+	}
+	return esfq_jhash_3words(q, info.dst, info.src, info.proto);
+}
+
+static inline void esfq_link(struct esfq_sched_data *q, esfq_index x)
+{
+	esfq_index p, n;
+	int d = q->qs[x].qlen + q->depth;
+
+	p = d;
+	n = q->dep[d].next;
+	q->dep[x].next = n;
+	q->dep[x].prev = p;
+	q->dep[p].next = q->dep[n].prev = x;
+}
+
+static inline void esfq_dec(struct esfq_sched_data *q, esfq_index x)
+{
+	esfq_index p, n;
+
+	n = q->dep[x].next;
+	p = q->dep[x].prev;
+	q->dep[p].next = n;
+	q->dep[n].prev = p;
+
+	if (n == p && q->max_depth == q->qs[x].qlen + 1)
+		q->max_depth--;
+
+	esfq_link(q, x);
+}
+
+static inline void esfq_inc(struct esfq_sched_data *q, esfq_index x)
+{
+	esfq_index p, n;
+	int d;
+
+	n = q->dep[x].next;
+	p = q->dep[x].prev;
+	q->dep[p].next = n;
+	q->dep[n].prev = p;
+	d = q->qs[x].qlen;
+	if (q->max_depth < d)
+		q->max_depth = d;
+
+	esfq_link(q, x);
+}
+
+static unsigned int esfq_drop(struct Qdisc *sch)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	esfq_index d = q->max_depth;
+	struct sk_buff *skb;
+	unsigned int len;
+
+	/* Queue is full! Find the longest slot and
+	   drop a packet from it */
+
+	if (d > 1) {
+		esfq_index x = q->dep[d+q->depth].next;
+		skb = q->qs[x].prev;
+		len = skb->len;
+		__skb_unlink(skb, &q->qs[x]);
+		kfree_skb(skb);
+		esfq_dec(q, x);
+		sch->q.qlen--;
+		sch->qstats.drops++;
+		sch->qstats.backlog -= len;
+		return len;
+	}
+
+	if (d == 1) {
+		/* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
+		d = q->next[q->tail];
+		q->next[q->tail] = q->next[d];
+		q->allot[q->next[d]] += q->quantum;
+		skb = q->qs[d].prev;
+		len = skb->len;
+		__skb_unlink(skb, &q->qs[d]);
+		kfree_skb(skb);
+		esfq_dec(q, d);
+		sch->q.qlen--;
+		q->ht[q->hash[d]] = q->depth;
+		sch->qstats.drops++;
+		sch->qstats.backlog -= len;
+		return len;
+	}
+
+	return 0;
+}
+
+static void esfq_q_enqueue(struct sk_buff *skb, struct esfq_sched_data *q, unsigned int end)
+{
+	unsigned hash = esfq_hash(q, skb);
+	unsigned depth = q->depth;
+	esfq_index x;
+
+	x = q->ht[hash];
+	if (x == depth) {
+		q->ht[hash] = x = q->dep[depth].next;
+		q->hash[x] = hash;
+	}
+
+	if (end == ESFQ_TAIL)
+		__skb_queue_tail(&q->qs[x], skb);
+	else
+		__skb_queue_head(&q->qs[x], skb);
+
+	esfq_inc(q, x);
+	if (q->qs[x].qlen == 1) {		/* The flow is new */
+		if (q->tail == depth) {	/* It is the first flow */
+			q->tail = x;
+			q->next[x] = x;
+			q->allot[x] = q->quantum;
+		} else {
+			q->next[x] = q->next[q->tail];
+			q->next[q->tail] = x;
+			q->tail = x;
+		}
+	}
+}
+
+static int esfq_enqueue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	esfq_q_enqueue(skb, q, ESFQ_TAIL);
+	sch->qstats.backlog += skb->len;
+	if (++sch->q.qlen < q->limit-1) {
+		sch->bstats.bytes += skb->len;
+		sch->bstats.packets++;
+		return 0;
+	}
+
+	sch->qstats.drops++;
+	esfq_drop(sch);
+	return NET_XMIT_CN;
+}
+
+
+static int esfq_requeue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	esfq_q_enqueue(skb, q, ESFQ_HEAD);
+	sch->qstats.backlog += skb->len;
+	if (++sch->q.qlen < q->limit - 1) {
+		sch->qstats.requeues++;
+		return 0;
+	}
+
+	sch->qstats.drops++;
+	esfq_drop(sch);
+	return NET_XMIT_CN;
+}
+
+static struct sk_buff *esfq_q_dequeue(struct esfq_sched_data *q)
+{
+	struct sk_buff *skb;
+	unsigned depth = q->depth;
+	esfq_index a, old_a;
+
+	/* No active slots */
+	if (q->tail == depth)
+		return NULL;
+
+	a = old_a = q->next[q->tail];
+
+	/* Grab packet */
+	skb = __skb_dequeue(&q->qs[a]);
+	esfq_dec(q, a);
+
+	/* Is the slot empty? */
+	if (q->qs[a].qlen == 0) {
+		q->ht[q->hash[a]] = depth;
+		a = q->next[a];
+		if (a == old_a) {
+			q->tail = depth;
+			return skb;
+		}
+		q->next[q->tail] = a;
+		q->allot[a] += q->quantum;
+	} else if ((q->allot[a] -= skb->len) <= 0) {
+		q->tail = a;
+		a = q->next[a];
+		q->allot[a] += q->quantum;
+	}
+
+	return skb;
+}
+
+static struct sk_buff *esfq_dequeue(struct Qdisc* sch)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+
+	skb = esfq_q_dequeue(q);
+	if (skb == NULL)
+		return NULL;
+	sch->q.qlen--;
+	sch->qstats.backlog -= skb->len;
+	return skb;
+}
+
+static void esfq_q_destroy(struct esfq_sched_data *q)
+{
+	del_timer(&q->perturb_timer);
+	if(q->ht)
+		kfree(q->ht);
+	if(q->dep)
+		kfree(q->dep);
+	if(q->next)
+		kfree(q->next);
+	if(q->allot)
+		kfree(q->allot);
+	if(q->hash)
+		kfree(q->hash);
+	if(q->qs)
+		kfree(q->qs);
+}
+
+static void esfq_destroy(struct Qdisc *sch)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	esfq_q_destroy(q);
+}
+
+
+static void esfq_reset(struct Qdisc* sch)
+{
+	struct sk_buff *skb;
+
+	while ((skb = esfq_dequeue(sch)) != NULL)
+		kfree_skb(skb);
+}
+
+static void esfq_perturbation(unsigned long arg)
+{
+	struct Qdisc *sch = (struct Qdisc*)arg;
+	struct esfq_sched_data *q = qdisc_priv(sch);
+
+	q->perturbation = net_random()&0x1F;
+
+	if (q->perturb_period) {
+		q->perturb_timer.expires = jiffies + q->perturb_period;
+		add_timer(&q->perturb_timer);
+	}
+}
+
+static unsigned int esfq_check_hash(unsigned int kind)
+{
+	switch (kind) {
+	case TCA_SFQ_HASH_CTORIGDST:
+	case TCA_SFQ_HASH_CTORIGSRC:
+	case TCA_SFQ_HASH_CTREPLDST:
+	case TCA_SFQ_HASH_CTREPLSRC:
+	case TCA_SFQ_HASH_CTNATCHG:
+#ifndef CONFIG_NET_SCH_ESFQ_NFCT
+	{
+		if (net_ratelimit())
+			printk(KERN_WARNING "ESFQ: Conntrack hash types disabled in kernel config. Falling back to classic.\n");
+		return TCA_SFQ_HASH_CLASSIC;
+	}
+#endif
+	case TCA_SFQ_HASH_CLASSIC:
+	case TCA_SFQ_HASH_DST:
+	case TCA_SFQ_HASH_SRC:
+	case TCA_SFQ_HASH_FWMARK:
+		return kind;
+	default:
+	{
+		if (net_ratelimit())
+			printk(KERN_WARNING "ESFQ: Unknown hash type. Falling back to classic.\n");
+		return TCA_SFQ_HASH_CLASSIC;
+	}
+	}
+}
+
+static int esfq_q_init(struct esfq_sched_data *q, struct rtattr *opt)
+{
+	struct tc_esfq_qopt *ctl = RTA_DATA(opt);
+	esfq_index p = ~0U/2;
+	int i;
+
+	if (opt && opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
+		return -EINVAL;
+
+	q->perturbation = 0;
+	q->hash_kind = TCA_SFQ_HASH_CLASSIC;
+	q->max_depth = 0;
+	if (opt == NULL) {
+		q->perturb_period = 0;
+		q->hash_divisor = 1024;
+		q->tail = q->limit = q->depth = 128;
+
+	} else {
+		struct tc_esfq_qopt *ctl = RTA_DATA(opt);
+		if (ctl->quantum)
+			q->quantum = ctl->quantum;
+		q->perturb_period = ctl->perturb_period*HZ;
+		q->hash_divisor = ctl->divisor ? : 1024;
+		q->tail = q->limit = q->depth = ctl->flows ? : 128;
+
+		if ( q->depth > p - 1 )
+			return -EINVAL;
+
+		if (ctl->limit)
+			q->limit = min_t(u32, ctl->limit, q->depth);
+
+		if (ctl->hash_kind) {
+			q->hash_kind = esfq_check_hash(ctl->hash_kind);
+		}
+	}
+
+	q->ht = kmalloc(q->hash_divisor*sizeof(esfq_index), GFP_KERNEL);
+	if (!q->ht)
+		goto err_case;
+	q->dep = kmalloc((1+q->depth*2)*sizeof(struct esfq_head), GFP_KERNEL);
+	if (!q->dep)
+		goto err_case;
+	q->next = kmalloc(q->depth*sizeof(esfq_index), GFP_KERNEL);
+	if (!q->next)
+		goto err_case;
+	q->allot = kmalloc(q->depth*sizeof(short), GFP_KERNEL);
+	if (!q->allot)
+		goto err_case;
+	q->hash = kmalloc(q->depth*sizeof(unsigned short), GFP_KERNEL);
+	if (!q->hash)
+		goto err_case;
+	q->qs = kmalloc(q->depth*sizeof(struct sk_buff_head), GFP_KERNEL);
+	if (!q->qs)
+		goto err_case;
+
+	for (i=0; i< q->hash_divisor; i++)
+		q->ht[i] = q->depth;
+	for (i=0; i<q->depth; i++) {
+		skb_queue_head_init(&q->qs[i]);
+		q->dep[i+q->depth].next = i+q->depth;
+		q->dep[i+q->depth].prev = i+q->depth;
+	}
+
+	for (i=0; i<q->depth; i++)
+		esfq_link(q, i);
+	return 0;
+err_case:
+	esfq_q_destroy(q);
+	return -ENOBUFS;
+}
+
+static int esfq_init(struct Qdisc *sch, struct rtattr *opt)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	int err;
+
+	q->quantum = psched_mtu(sch->dev); /* default */
+	if ((err = esfq_q_init(q, opt)))
+		return err;
+
+	init_timer(&q->perturb_timer);
+	q->perturb_timer.data = (unsigned long)sch;
+	q->perturb_timer.function = esfq_perturbation;
+	if (q->perturb_period) {
+		q->perturb_timer.expires = jiffies + q->perturb_period;
+		add_timer(&q->perturb_timer);
+	}
+
+	return 0;
+}
+
+static int esfq_change(struct Qdisc *sch, struct rtattr *opt)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	struct esfq_sched_data new;
+	struct sk_buff *skb;
+	int err;
+
+	/* set up new queue */
+	memset(&new, 0, sizeof(struct esfq_sched_data));
+	new.quantum = psched_mtu(sch->dev); /* default */
+	if ((err = esfq_q_init(&new, opt)))
+		return err;
+
+	/* copy all packets from the old queue to the new queue */
+	sch_tree_lock(sch);
+	while ((skb = esfq_q_dequeue(q)) != NULL)
+		esfq_q_enqueue(skb, &new, ESFQ_TAIL);
+
+	/* clean up the old queue */
+	esfq_q_destroy(q);
+
+	/* copy elements of the new queue into the old queue */
+	q->perturb_period = new.perturb_period;
+	q->quantum        = new.quantum;
+	q->limit          = new.limit;
+	q->depth          = new.depth;
+	q->hash_divisor   = new.hash_divisor;
+	q->hash_kind      = new.hash_kind;
+	q->tail           = new.tail;
+	q->max_depth      = new.max_depth;
+	q->ht    = new.ht;
+	q->dep   = new.dep;
+	q->next  = new.next;
+	q->allot = new.allot;
+	q->hash  = new.hash;
+	q->qs    = new.qs;
+
+	/* finish up */
+	if (q->perturb_period) {
+		q->perturb_timer.expires = jiffies + q->perturb_period;
+		add_timer(&q->perturb_timer);
+	} else {
+		q->perturbation = 0;
+	}
+	sch_tree_unlock(sch);
+	return 0;
+}
+
+static int esfq_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct esfq_sched_data *q = qdisc_priv(sch);
+	unsigned char *b = skb->tail;
+	struct tc_esfq_qopt opt;
+
+	opt.quantum = q->quantum;
+	opt.perturb_period = q->perturb_period/HZ;
+
+	opt.limit = q->limit;
+	opt.divisor = q->hash_divisor;
+	opt.flows = q->depth;
+	opt.hash_kind = q->hash_kind;
+
+	RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
+
+	return skb->len;
+
+rtattr_failure:
+	skb_trim(skb, b - skb->data);
+	return -1;
+}
+
+static struct Qdisc_ops esfq_qdisc_ops =
+{
+	.next		=	NULL,
+	.cl_ops		=	NULL,
+	.id		=	"esfq",
+	.priv_size	=	sizeof(struct esfq_sched_data),
+	.enqueue	=	esfq_enqueue,
+	.dequeue	=	esfq_dequeue,
+	.requeue	=	esfq_requeue,
+	.drop		=	esfq_drop,
+	.init		=	esfq_init,
+	.reset		=	esfq_reset,
+	.destroy	=	esfq_destroy,
+	.change		=	esfq_change,
+	.dump		=	esfq_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init esfq_module_init(void)
+{
+	return register_qdisc(&esfq_qdisc_ops);
+}
+static void __exit esfq_module_exit(void)
+{
+	unregister_qdisc(&esfq_qdisc_ops);
+}
+module_init(esfq_module_init)
+module_exit(esfq_module_exit)
+MODULE_LICENSE("GPL");