linux/drivers/net/shaper.c
Christoph Hellwig bc971dee6e [SHAPER]: Switch to spinlocks.
Dave, you were right and the sleeping locks in shaper were
broken. Markus Kanet noticed this and also tested the patch below that
switches locking to spinlocks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-05 15:03:46 -07:00

697 lines
16 KiB
C

/*
* Simple traffic shaper for Linux NET3.
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.redhat.com
*
* 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.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
*
* Algorithm:
*
* Queue Frame:
* Compute time length of frame at regulated speed
* Add frame to queue at appropriate point
* Adjust time length computation for followup frames
* Any frame that falls outside of its boundaries is freed
*
* We work to the following constants
*
* SHAPER_QLEN Maximum queued frames
* SHAPER_LATENCY Bounding latency on a frame. Leaving this latency
* window drops the frame. This stops us queueing
* frames for a long time and confusing a remote
* host.
* SHAPER_MAXSLIP Maximum time a priority frame may jump forward.
* That bounds the penalty we will inflict on low
* priority traffic.
* SHAPER_BURST Time range we call "now" in order to reduce
* system load. The more we make this the burstier
* the behaviour, the better local performance you
* get through packet clustering on routers and the
* worse the remote end gets to judge rtts.
*
* This is designed to handle lower speed links ( < 200K/second or so). We
* run off a 100-150Hz base clock typically. This gives us a resolution at
* 200Kbit/second of about 2Kbit or 256 bytes. Above that our timer
* resolution may start to cause much more burstiness in the traffic. We
* could avoid a lot of that by calling kick_shaper() at the end of the
* tied device transmissions. If you run above about 100K second you
* may need to tune the supposed speed rate for the right values.
*
* BUGS:
* Downing the interface under the shaper before the shaper
* will render your machine defunct. Don't for now shape over
* PPP or SLIP therefore!
* This will be fixed in BETA4
*
* Update History :
*
* bh_atomic() SMP races fixes and rewritten the locking code to
* be SMP safe and irq-mask friendly.
* NOTE: we can't use start_bh_atomic() in kick_shaper()
* because it's going to be recalled from an irq handler,
* and synchronize_bh() is a nono if called from irq context.
* 1999 Andrea Arcangeli
*
* Device statistics (tx_pakets, tx_bytes,
* tx_drops: queue_over_time and collisions: max_queue_exceded)
* 1999/06/18 Jordi Murgo <savage@apostols.org>
*
* Use skb->cb for private data.
* 2000/03 Andi Kleen
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/if_shaper.h>
#include <net/dst.h>
#include <net/arp.h>
struct shaper_cb {
unsigned long shapeclock; /* Time it should go out */
unsigned long shapestamp; /* Stamp for shaper */
__u32 shapelatency; /* Latency on frame */
__u32 shapelen; /* Frame length in clocks */
__u16 shapepend; /* Pending */
};
#define SHAPERCB(skb) ((struct shaper_cb *) ((skb)->cb))
static int sh_debug; /* Debug flag */
#define SHAPER_BANNER "CymruNet Traffic Shaper BETA 0.04 for Linux 2.1\n"
static void shaper_kick(struct shaper *sh);
/*
* Compute clocks on a buffer
*/
static int shaper_clocks(struct shaper *shaper, struct sk_buff *skb)
{
int t=skb->len/shaper->bytespertick;
return t;
}
/*
* Set the speed of a shaper. We compute this in bytes per tick since
* thats how the machine wants to run. Quoted input is in bits per second
* as is traditional (note not BAUD). We assume 8 bit bytes.
*/
static void shaper_setspeed(struct shaper *shaper, int bitspersec)
{
shaper->bitspersec=bitspersec;
shaper->bytespertick=(bitspersec/HZ)/8;
if(!shaper->bytespertick)
shaper->bytespertick++;
}
/*
* Throw a frame at a shaper.
*/
static int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct shaper *shaper = dev->priv;
struct sk_buff *ptr;
spin_lock(&shaper->lock);
ptr=shaper->sendq.prev;
/*
* Set up our packet details
*/
SHAPERCB(skb)->shapelatency=0;
SHAPERCB(skb)->shapeclock=shaper->recovery;
if(time_before(SHAPERCB(skb)->shapeclock, jiffies))
SHAPERCB(skb)->shapeclock=jiffies;
skb->priority=0; /* short term bug fix */
SHAPERCB(skb)->shapestamp=jiffies;
/*
* Time slots for this packet.
*/
SHAPERCB(skb)->shapelen= shaper_clocks(shaper,skb);
#ifdef SHAPER_COMPLEX /* and broken.. */
while(ptr && ptr!=(struct sk_buff *)&shaper->sendq)
{
if(ptr->pri<skb->pri
&& jiffies - SHAPERCB(ptr)->shapeclock < SHAPER_MAXSLIP)
{
struct sk_buff *tmp=ptr->prev;
/*
* It goes before us therefore we slip the length
* of the new frame.
*/
SHAPERCB(ptr)->shapeclock+=SHAPERCB(skb)->shapelen;
SHAPERCB(ptr)->shapelatency+=SHAPERCB(skb)->shapelen;
/*
* The packet may have slipped so far back it
* fell off.
*/
if(SHAPERCB(ptr)->shapelatency > SHAPER_LATENCY)
{
skb_unlink(ptr);
dev_kfree_skb(ptr);
}
ptr=tmp;
}
else
break;
}
if(ptr==NULL || ptr==(struct sk_buff *)&shaper->sendq)
skb_queue_head(&shaper->sendq,skb);
else
{
struct sk_buff *tmp;
/*
* Set the packet clock out time according to the
* frames ahead. Im sure a bit of thought could drop
* this loop.
*/
for(tmp=skb_peek(&shaper->sendq); tmp!=NULL && tmp!=ptr; tmp=tmp->next)
SHAPERCB(skb)->shapeclock+=tmp->shapelen;
skb_append(ptr,skb);
}
#else
{
struct sk_buff *tmp;
/*
* Up our shape clock by the time pending on the queue
* (Should keep this in the shaper as a variable..)
*/
for(tmp=skb_peek(&shaper->sendq); tmp!=NULL &&
tmp!=(struct sk_buff *)&shaper->sendq; tmp=tmp->next)
SHAPERCB(skb)->shapeclock+=SHAPERCB(tmp)->shapelen;
/*
* Queue over time. Spill packet.
*/
if(SHAPERCB(skb)->shapeclock-jiffies > SHAPER_LATENCY) {
dev_kfree_skb(skb);
shaper->stats.tx_dropped++;
} else
skb_queue_tail(&shaper->sendq, skb);
}
#endif
if(sh_debug)
printk("Frame queued.\n");
if(skb_queue_len(&shaper->sendq)>SHAPER_QLEN)
{
ptr=skb_dequeue(&shaper->sendq);
dev_kfree_skb(ptr);
shaper->stats.collisions++;
}
shaper_kick(shaper);
spin_unlock(&shaper->lock);
return 0;
}
/*
* Transmit from a shaper
*/
static void shaper_queue_xmit(struct shaper *shaper, struct sk_buff *skb)
{
struct sk_buff *newskb=skb_clone(skb, GFP_ATOMIC);
if(sh_debug)
printk("Kick frame on %p\n",newskb);
if(newskb)
{
newskb->dev=shaper->dev;
newskb->priority=2;
if(sh_debug)
printk("Kick new frame to %s, %d\n",
shaper->dev->name,newskb->priority);
dev_queue_xmit(newskb);
shaper->stats.tx_bytes += skb->len;
shaper->stats.tx_packets++;
if(sh_debug)
printk("Kicked new frame out.\n");
dev_kfree_skb(skb);
}
}
/*
* Timer handler for shaping clock
*/
static void shaper_timer(unsigned long data)
{
struct shaper *shaper = (struct shaper *)data;
spin_lock(&shaper->lock);
shaper_kick(shaper);
spin_unlock(&shaper->lock);
}
/*
* Kick a shaper queue and try and do something sensible with the
* queue.
*/
static void shaper_kick(struct shaper *shaper)
{
struct sk_buff *skb;
/*
* Walk the list (may be empty)
*/
while((skb=skb_peek(&shaper->sendq))!=NULL)
{
/*
* Each packet due to go out by now (within an error
* of SHAPER_BURST) gets kicked onto the link
*/
if(sh_debug)
printk("Clock = %ld, jiffies = %ld\n", SHAPERCB(skb)->shapeclock, jiffies);
if(time_before_eq(SHAPERCB(skb)->shapeclock, jiffies + SHAPER_BURST))
{
/*
* Pull the frame and get interrupts back on.
*/
skb_unlink(skb);
if (shaper->recovery <
SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen)
shaper->recovery = SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen;
/*
* Pass on to the physical target device via
* our low level packet thrower.
*/
SHAPERCB(skb)->shapepend=0;
shaper_queue_xmit(shaper, skb); /* Fire */
}
else
break;
}
/*
* Next kick.
*/
if(skb!=NULL)
mod_timer(&shaper->timer, SHAPERCB(skb)->shapeclock);
}
/*
* Bring the interface up. We just disallow this until a
* bind.
*/
static int shaper_open(struct net_device *dev)
{
struct shaper *shaper=dev->priv;
/*
* Can't open until attached.
* Also can't open until speed is set, or we'll get
* a division by zero.
*/
if(shaper->dev==NULL)
return -ENODEV;
if(shaper->bitspersec==0)
return -EINVAL;
return 0;
}
/*
* Closing a shaper flushes the queues.
*/
static int shaper_close(struct net_device *dev)
{
struct shaper *shaper=dev->priv;
struct sk_buff *skb;
while ((skb = skb_dequeue(&shaper->sendq)) != NULL)
dev_kfree_skb(skb);
spin_lock_bh(&shaper->lock);
shaper_kick(shaper);
spin_unlock_bh(&shaper->lock);
del_timer_sync(&shaper->timer);
return 0;
}
/*
* Revectored calls. We alter the parameters and call the functions
* for our attached device. This enables us to bandwidth allocate after
* ARP and other resolutions and not before.
*/
static struct net_device_stats *shaper_get_stats(struct net_device *dev)
{
struct shaper *sh=dev->priv;
return &sh->stats;
}
static int shaper_header(struct sk_buff *skb, struct net_device *dev,
unsigned short type, void *daddr, void *saddr, unsigned len)
{
struct shaper *sh=dev->priv;
int v;
if(sh_debug)
printk("Shaper header\n");
skb->dev=sh->dev;
v=sh->hard_header(skb,sh->dev,type,daddr,saddr,len);
skb->dev=dev;
return v;
}
static int shaper_rebuild_header(struct sk_buff *skb)
{
struct shaper *sh=skb->dev->priv;
struct net_device *dev=skb->dev;
int v;
if(sh_debug)
printk("Shaper rebuild header\n");
skb->dev=sh->dev;
v=sh->rebuild_header(skb);
skb->dev=dev;
return v;
}
#if 0
static int shaper_cache(struct neighbour *neigh, struct hh_cache *hh)
{
struct shaper *sh=neigh->dev->priv;
struct net_device *tmp;
int ret;
if(sh_debug)
printk("Shaper header cache bind\n");
tmp=neigh->dev;
neigh->dev=sh->dev;
ret=sh->hard_header_cache(neigh,hh);
neigh->dev=tmp;
return ret;
}
static void shaper_cache_update(struct hh_cache *hh, struct net_device *dev,
unsigned char *haddr)
{
struct shaper *sh=dev->priv;
if(sh_debug)
printk("Shaper cache update\n");
sh->header_cache_update(hh, sh->dev, haddr);
}
#endif
#ifdef CONFIG_INET
static int shaper_neigh_setup(struct neighbour *n)
{
#ifdef CONFIG_INET
if (n->nud_state == NUD_NONE) {
n->ops = &arp_broken_ops;
n->output = n->ops->output;
}
#endif
return 0;
}
static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
{
#ifdef CONFIG_INET
if (p->tbl->family == AF_INET) {
p->neigh_setup = shaper_neigh_setup;
p->ucast_probes = 0;
p->mcast_probes = 0;
}
#endif
return 0;
}
#else /* !(CONFIG_INET) */
static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
{
return 0;
}
#endif
static int shaper_attach(struct net_device *shdev, struct shaper *sh, struct net_device *dev)
{
sh->dev = dev;
sh->hard_start_xmit=dev->hard_start_xmit;
sh->get_stats=dev->get_stats;
if(dev->hard_header)
{
sh->hard_header=dev->hard_header;
shdev->hard_header = shaper_header;
}
else
shdev->hard_header = NULL;
if(dev->rebuild_header)
{
sh->rebuild_header = dev->rebuild_header;
shdev->rebuild_header = shaper_rebuild_header;
}
else
shdev->rebuild_header = NULL;
#if 0
if(dev->hard_header_cache)
{
sh->hard_header_cache = dev->hard_header_cache;
shdev->hard_header_cache= shaper_cache;
}
else
{
shdev->hard_header_cache= NULL;
}
if(dev->header_cache_update)
{
sh->header_cache_update = dev->header_cache_update;
shdev->header_cache_update = shaper_cache_update;
}
else
shdev->header_cache_update= NULL;
#else
shdev->header_cache_update = NULL;
shdev->hard_header_cache = NULL;
#endif
shdev->neigh_setup = shaper_neigh_setup_dev;
shdev->hard_header_len=dev->hard_header_len;
shdev->type=dev->type;
shdev->addr_len=dev->addr_len;
shdev->mtu=dev->mtu;
sh->bitspersec=0;
return 0;
}
static int shaper_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
struct shaperconf *ss= (struct shaperconf *)&ifr->ifr_ifru;
struct shaper *sh=dev->priv;
if(ss->ss_cmd == SHAPER_SET_DEV || ss->ss_cmd == SHAPER_SET_SPEED)
{
if(!capable(CAP_NET_ADMIN))
return -EPERM;
}
switch(ss->ss_cmd)
{
case SHAPER_SET_DEV:
{
struct net_device *them=__dev_get_by_name(ss->ss_name);
if(them==NULL)
return -ENODEV;
if(sh->dev)
return -EBUSY;
return shaper_attach(dev,dev->priv, them);
}
case SHAPER_GET_DEV:
if(sh->dev==NULL)
return -ENODEV;
strcpy(ss->ss_name, sh->dev->name);
return 0;
case SHAPER_SET_SPEED:
shaper_setspeed(sh,ss->ss_speed);
return 0;
case SHAPER_GET_SPEED:
ss->ss_speed=sh->bitspersec;
return 0;
default:
return -EINVAL;
}
}
static void shaper_init_priv(struct net_device *dev)
{
struct shaper *sh = dev->priv;
skb_queue_head_init(&sh->sendq);
init_timer(&sh->timer);
sh->timer.function=shaper_timer;
sh->timer.data=(unsigned long)sh;
spin_lock_init(&sh->lock);
}
/*
* Add a shaper device to the system
*/
static void __init shaper_setup(struct net_device *dev)
{
/*
* Set up the shaper.
*/
SET_MODULE_OWNER(dev);
shaper_init_priv(dev);
dev->open = shaper_open;
dev->stop = shaper_close;
dev->hard_start_xmit = shaper_start_xmit;
dev->get_stats = shaper_get_stats;
dev->set_multicast_list = NULL;
/*
* Intialise the packet queues
*/
/*
* Handlers for when we attach to a device.
*/
dev->hard_header = shaper_header;
dev->rebuild_header = shaper_rebuild_header;
#if 0
dev->hard_header_cache = shaper_cache;
dev->header_cache_update= shaper_cache_update;
#endif
dev->neigh_setup = shaper_neigh_setup_dev;
dev->do_ioctl = shaper_ioctl;
dev->hard_header_len = 0;
dev->type = ARPHRD_ETHER; /* initially */
dev->set_mac_address = NULL;
dev->mtu = 1500;
dev->addr_len = 0;
dev->tx_queue_len = 10;
dev->flags = 0;
}
static int shapers = 1;
#ifdef MODULE
module_param(shapers, int, 0);
MODULE_PARM_DESC(shapers, "Traffic shaper: maximum number of shapers");
#else /* MODULE */
static int __init set_num_shapers(char *str)
{
shapers = simple_strtol(str, NULL, 0);
return 1;
}
__setup("shapers=", set_num_shapers);
#endif /* MODULE */
static struct net_device **devs;
static unsigned int shapers_registered = 0;
static int __init shaper_init(void)
{
int i;
size_t alloc_size;
struct net_device *dev;
char name[IFNAMSIZ];
if (shapers < 1)
return -ENODEV;
alloc_size = sizeof(*dev) * shapers;
devs = kmalloc(alloc_size, GFP_KERNEL);
if (!devs)
return -ENOMEM;
memset(devs, 0, alloc_size);
for (i = 0; i < shapers; i++) {
snprintf(name, IFNAMSIZ, "shaper%d", i);
dev = alloc_netdev(sizeof(struct shaper), name,
shaper_setup);
if (!dev)
break;
if (register_netdev(dev)) {
free_netdev(dev);
break;
}
devs[i] = dev;
shapers_registered++;
}
if (!shapers_registered) {
kfree(devs);
devs = NULL;
}
return (shapers_registered ? 0 : -ENODEV);
}
static void __exit shaper_exit (void)
{
int i;
for (i = 0; i < shapers_registered; i++) {
if (devs[i]) {
unregister_netdev(devs[i]);
free_netdev(devs[i]);
}
}
kfree(devs);
devs = NULL;
}
module_init(shaper_init);
module_exit(shaper_exit);
MODULE_LICENSE("GPL");