/* * 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; if (down_trylock(&shaper->sem)) 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_kick(shaper); up(&shaper->sem); 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; if (!down_trylock(&shaper->sem)) { shaper_kick(shaper); up(&shaper->sem); } else mod_timer(&shaper->timer, jiffies); } /* * 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); } /* * Flush the shaper queues on a closedown */ static void shaper_flush(struct shaper *shaper) { struct sk_buff *skb; down(&shaper->sem); while((skb=skb_dequeue(&shaper->sendq))!=NULL) dev_kfree_skb(skb); shaper_kick(shaper); up(&shaper->sem); } /* * 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 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; } /* * 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");