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/*
* 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/sched.h>
#include <linux/ptrace.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 <net/dst.h>
#include <net/arp.h>
#include <linux/if_shaper.h>
struct shaper_cb {
__u32 shapelatency; /* Latency on frame */
__u32 shapeclock; /* Time it should go out */
__u32 shapelen; /* Frame length in clocks */
__u32 shapestamp; /* Stamp for shaper */
__u16 shapepend; /* Pending */
};
#define SHAPERCB(skb) ((struct shaper_cb *) ((skb)->cb))
int sh_debug; /* Debug flag */
#define SHAPER_BANNER "CymruNet Traffic Shaper BETA 0.04 for Linux 2.1\n"
/*
* Locking
*/
static int shaper_lock(struct shaper *sh)
{
/*
* Lock in an interrupt must fail
*/
while (test_and_set_bit(0, &sh->locked))
{
if (!in_interrupt())
sleep_on(&sh->wait_queue);
else
return 0;
}
return 1;
}
static void shaper_kick(struct shaper *sh);
static void shaper_unlock(struct shaper *sh)
{
clear_bit(0, &sh->locked);
wake_up(&sh->wait_queue);
shaper_kick(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_qframe(struct shaper *shaper, struct sk_buff *skb)
{
struct sk_buff *ptr;
/*
* Get ready to work on this shaper. Lock may fail if its
* an interrupt and locked.
*/
if(!shaper_lock(shaper))
return -1;
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_unlock(shaper);
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 *sh=(struct shaper *)data;
shaper_kick(sh);
}
/*
* Kick a shaper queue and try and do something sensible with the
* queue.
*/
static void shaper_kick(struct shaper *shaper)
{
struct sk_buff *skb;
/*
* Shaper unlock will kick
*/
if (test_and_set_bit(0, &shaper->locked))
{
if(sh_debug)
printk("Shaper locked.\n");
mod_timer(&shaper->timer, jiffies);
return;
}
/*
* 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 = %d, 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);
clear_bit(0, &shaper->locked);
}
/*
* Flush the shaper queues on a closedown
*/
static void shaper_flush(struct shaper *shaper)
{
struct sk_buff *skb;
if(!shaper_lock(shaper))
{
printk(KERN_ERR "shaper: shaper_flush() called by an irq!\n");
return;
}
while((skb=skb_dequeue(&shaper->sendq))!=NULL)
dev_kfree_skb(skb);
shaper_unlock(shaper);
}
/*
* 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;
shaper_flush(shaper);
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 int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct shaper *sh=dev->priv;
return shaper_qframe(sh, skb);
}
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_data;
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;
init_waitqueue_head(&sh->wait_queue);
}
/*
* Add a shaper device to the system
*/
static int __init shaper_probe(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;
/*
* Shaper is ok
*/
return 0;
}
static int shapers = 1;
#ifdef MODULE
MODULE_PARM(shapers, "i");
MODULE_PARM_DESC(shapers, "Traffic shaper: maximum nuber 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 int __init shaper_init(void)
{
int i, err;
size_t alloc_size;
struct shaper *sp;
unsigned int shapers_registered = 0;
if (shapers < 1)
return -ENODEV;
alloc_size = (sizeof(*devs) * shapers) +
(sizeof(struct shaper) * shapers);
devs = kmalloc(alloc_size, GFP_KERNEL);
if (!devs)
return -ENOMEM;
memset(devs, 0, alloc_size);
sp = (struct shaper *) &devs[shapers];
for (i = 0; i < shapers; i++) {
err = dev_alloc_name(&devs[i], "shaper%d");
if (err < 0)
break;
devs[i].init = shaper_probe;
devs[i].priv = &sp[i];
if (register_netdev(&devs[i]))
break;
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; i++)
unregister_netdev(&devs[i]);
kfree(devs);
devs = NULL;
}
module_init(shaper_init);
module_exit(shaper_exit);
MODULE_LICENSE("GPL");
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