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linux/net/sched/cls_fw.c
Thomas Graf c5c13fafd6 [PKT_SCHED]: improve hashing performance of cls_fw 
Calculate hashtable size to fit into a page instead of a hardcoded
256 buckets hash table. Results in a 1024 buckets hashtable on
most systems.

Replace old naive extract-8-lsb-bits algorithm with a better
algorithm xor'ing 3 or 4 bit fields at the size of the hashtable
array index in order to improve distribution if the majority of
the lower bits are unused while keeping zero collision behaviour
for the most common use case.

Thanks to Wang Jian <lark@linux.net.cn> for bringing this issue
to attention and to Eran Mann <emann@mrv.com> for the initial
idea for this new algorithm.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-24 20:19:54 -07:00

402 lines
8.3 KiB
C
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/*
* net/sched/cls_fw.c Classifier mapping ipchains' fwmark to traffic class.
*
* 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:
* 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
*
* JHS: We should remove the CONFIG_NET_CLS_IND from here
* eventually when the meta match extension is made available
*
*/
#include <linux/config.h>
#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/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 <linux/netfilter.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/act_api.h>
#include <net/pkt_cls.h>
#define HTSIZE (PAGE_SIZE/sizeof(struct fw_filter *))
struct fw_head
{
struct fw_filter *ht[HTSIZE];
};
struct fw_filter
{
struct fw_filter *next;
u32 id;
struct tcf_result res;
#ifdef CONFIG_NET_CLS_IND
char indev[IFNAMSIZ];
#endif /* CONFIG_NET_CLS_IND */
struct tcf_exts exts;
};
static struct tcf_ext_map fw_ext_map = {
.action = TCA_FW_ACT,
.police = TCA_FW_POLICE
};
static __inline__ int fw_hash(u32 handle)
{
if (HTSIZE == 4096)
return ((handle >> 24) & 0xFFF) ^
((handle >> 12) & 0xFFF) ^
(handle & 0xFFF);
else if (HTSIZE == 2048)
return ((handle >> 22) & 0x7FF) ^
((handle >> 11) & 0x7FF) ^
(handle & 0x7FF);
else if (HTSIZE == 1024)
return ((handle >> 20) & 0x3FF) ^
((handle >> 10) & 0x3FF) ^
(handle & 0x3FF);
else if (HTSIZE == 512)
return (handle >> 27) ^
((handle >> 18) & 0x1FF) ^
((handle >> 9) & 0x1FF) ^
(handle & 0x1FF);
else if (HTSIZE == 256) {
u8 *t = (u8 *) &handle;
return t[0] ^ t[1] ^ t[2] ^ t[3];
} else
return handle & (HTSIZE - 1);
}
static int fw_classify(struct sk_buff *skb, struct tcf_proto *tp,
struct tcf_result *res)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f;
int r;
#ifdef CONFIG_NETFILTER
u32 id = skb->nfmark;
#else
u32 id = 0;
#endif
if (head != NULL) {
for (f=head->ht[fw_hash(id)]; f; f=f->next) {
if (f->id == id) {
*res = f->res;
#ifdef CONFIG_NET_CLS_IND
if (!tcf_match_indev(skb, f->indev))
continue;
#endif /* CONFIG_NET_CLS_IND */
r = tcf_exts_exec(skb, &f->exts, res);
if (r < 0)
continue;
return r;
}
}
} else {
/* 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 unsigned long fw_get(struct tcf_proto *tp, u32 handle)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f;
if (head == NULL)
return 0;
for (f=head->ht[fw_hash(handle)]; f; f=f->next) {
if (f->id == handle)
return (unsigned long)f;
}
return 0;
}
static void fw_put(struct tcf_proto *tp, unsigned long f)
{
}
static int fw_init(struct tcf_proto *tp)
{
return 0;
}
static inline void
fw_delete_filter(struct tcf_proto *tp, struct fw_filter *f)
{
tcf_unbind_filter(tp, &f->res);
tcf_exts_destroy(tp, &f->exts);
kfree(f);
}
static void fw_destroy(struct tcf_proto *tp)
{
struct fw_head *head = (struct fw_head*)xchg(&tp->root, NULL);
struct fw_filter *f;
int h;
if (head == NULL)
return;
for (h=0; h<HTSIZE; h++) {
while ((f=head->ht[h]) != NULL) {
head->ht[h] = f->next;
fw_delete_filter(tp, f);
}
}
kfree(head);
}
static int fw_delete(struct tcf_proto *tp, unsigned long arg)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f = (struct fw_filter*)arg;
struct fw_filter **fp;
if (head == NULL || f == NULL)
goto out;
for (fp=&head->ht[fw_hash(f->id)]; *fp; fp = &(*fp)->next) {
if (*fp == f) {
tcf_tree_lock(tp);
*fp = f->next;
tcf_tree_unlock(tp);
fw_delete_filter(tp, f);
return 0;
}
}
out:
return -EINVAL;
}
static int
fw_change_attrs(struct tcf_proto *tp, struct fw_filter *f,
struct rtattr **tb, struct rtattr **tca, unsigned long base)
{
struct tcf_exts e;
int err;
err = tcf_exts_validate(tp, tb, tca[TCA_RATE-1], &e, &fw_ext_map);
if (err < 0)
return err;
err = -EINVAL;
if (tb[TCA_FW_CLASSID-1]) {
if (RTA_PAYLOAD(tb[TCA_FW_CLASSID-1]) != sizeof(u32))
goto errout;
f->res.classid = *(u32*)RTA_DATA(tb[TCA_FW_CLASSID-1]);
tcf_bind_filter(tp, &f->res, base);
}
#ifdef CONFIG_NET_CLS_IND
if (tb[TCA_FW_INDEV-1]) {
err = tcf_change_indev(tp, f->indev, tb[TCA_FW_INDEV-1]);
if (err < 0)
goto errout;
}
#endif /* CONFIG_NET_CLS_IND */
tcf_exts_change(tp, &f->exts, &e);
return 0;
errout:
tcf_exts_destroy(tp, &e);
return err;
}
static int fw_change(struct tcf_proto *tp, unsigned long base,
u32 handle,
struct rtattr **tca,
unsigned long *arg)
{
struct fw_head *head = (struct fw_head*)tp->root;
struct fw_filter *f = (struct fw_filter *) *arg;
struct rtattr *opt = tca[TCA_OPTIONS-1];
struct rtattr *tb[TCA_FW_MAX];
int err;
if (!opt)
return handle ? -EINVAL : 0;
if (rtattr_parse_nested(tb, TCA_FW_MAX, opt) < 0)
return -EINVAL;
if (f != NULL) {
if (f->id != handle && handle)
return -EINVAL;
return fw_change_attrs(tp, f, tb, tca, base);
}
if (!handle)
return -EINVAL;
if (head == NULL) {
head = kmalloc(sizeof(struct fw_head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
memset(head, 0, sizeof(*head));
tcf_tree_lock(tp);
tp->root = head;
tcf_tree_unlock(tp);
}
f = kmalloc(sizeof(struct fw_filter), GFP_KERNEL);
if (f == NULL)
return -ENOBUFS;
memset(f, 0, sizeof(*f));
f->id = handle;
err = fw_change_attrs(tp, f, tb, tca, base);
if (err < 0)
goto errout;
f->next = head->ht[fw_hash(handle)];
tcf_tree_lock(tp);
head->ht[fw_hash(handle)] = f;
tcf_tree_unlock(tp);
*arg = (unsigned long)f;
return 0;
errout:
if (f)
kfree(f);
return err;
}
static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct fw_head *head = (struct fw_head*)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 = head->ht[h]; f; f = f->next) {
if (arg->count < arg->skip) {
arg->count++;
continue;
}
if (arg->fn(tp, (unsigned long)f, arg) < 0) {
arg->stop = 1;
return;
}
arg->count++;
}
}
}
static int fw_dump(struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct fw_filter *f = (struct fw_filter*)fh;
unsigned char *b = skb->tail;
struct rtattr *rta;
if (f == NULL)
return skb->len;
t->tcm_handle = f->id;
if (!f->res.classid && !tcf_exts_is_available(&f->exts))
return skb->len;
rta = (struct rtattr*)b;
RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
if (f->res.classid)
RTA_PUT(skb, TCA_FW_CLASSID, 4, &f->res.classid);
#ifdef CONFIG_NET_CLS_IND
if (strlen(f->indev))
RTA_PUT(skb, TCA_FW_INDEV, IFNAMSIZ, f->indev);
#endif /* CONFIG_NET_CLS_IND */
if (tcf_exts_dump(skb, &f->exts, &fw_ext_map) < 0)
goto rtattr_failure;
rta->rta_len = skb->tail - b;
if (tcf_exts_dump_stats(skb, &f->exts, &fw_ext_map) < 0)
goto rtattr_failure;
return skb->len;
rtattr_failure:
skb_trim(skb, b - skb->data);
return -1;
}
static struct tcf_proto_ops cls_fw_ops = {
.next = NULL,
.kind = "fw",
.classify = fw_classify,
.init = fw_init,
.destroy = fw_destroy,
.get = fw_get,
.put = fw_put,
.change = fw_change,
.delete = fw_delete,
.walk = fw_walk,
.dump = fw_dump,
.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");
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