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   1 /*
   2  *                      Simple traffic shaper for Linux NET3.
   3  *
   4  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
   5  *                              http://www.redhat.com
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  13  *      warranty for any of this software. This material is provided
  14  *      "AS-IS" and at no charge.
  15  *
  16  *
  17  *      Algorithm:
  18  *
  19  *      Queue Frame:
  20  *              Compute time length of frame at regulated speed
  21  *              Add frame to queue at appropriate point
  22  *              Adjust time length computation for followup frames
  23  *              Any frame that falls outside of its boundaries is freed
  24  *
  25  *      We work to the following constants
  26  *
  27  *              SHAPER_QLEN     Maximum queued frames
  28  *              SHAPER_LATENCY  Bounding latency on a frame. Leaving this latency
  29  *                              window drops the frame. This stops us queueing
  30  *                              frames for a long time and confusing a remote
  31  *                              host.
  32  *              SHAPER_MAXSLIP  Maximum time a priority frame may jump forward.
  33  *                              That bounds the penalty we will inflict on low
  34  *                              priority traffic.
  35  *              SHAPER_BURST    Time range we call "now" in order to reduce
  36  *                              system load. The more we make this the burstier
  37  *                              the behaviour, the better local performance you
  38  *                              get through packet clustering on routers and the
  39  *                              worse the remote end gets to judge rtts.
  40  *
  41  *      This is designed to handle lower speed links ( < 200K/second or so). We
  42  *      run off a 100-150Hz base clock typically. This gives us a resolution at
  43  *      200Kbit/second of about 2Kbit or 256 bytes. Above that our timer
  44  *      resolution may start to cause much more burstiness in the traffic. We
  45  *      could avoid a lot of that by calling kick_shaper() at the end of the
  46  *      tied device transmissions. If you run above about 100K second you
  47  *      may need to tune the supposed speed rate for the right values.
  48  *
  49  *      BUGS:
  50  *              Downing the interface under the shaper before the shaper
  51  *              will render your machine defunct. Don't for now shape over
  52  *              PPP or SLIP therefore!
  53  *              This will be fixed in BETA4
  54  *
  55  * Update History :
  56  *
  57  *              bh_atomic() SMP races fixes and rewritten the locking code to
  58  *              be SMP safe and irq-mask friendly.
  59  *              NOTE: we can't use start_bh_atomic() in kick_shaper()
  60  *              because it's going to be recalled from an irq handler,
  61  *              and synchronize_bh() is a nono if called from irq context.
  62  *                                              1999  Andrea Arcangeli
  63  *
  64  *              Device statistics (tx_pakets, tx_bytes,
  65  *              tx_drops: queue_over_time and collisions: max_queue_exceded)
  66  *                               1999/06/18 Jordi Murgo <savage@apostols.org>
  67  *
  68  *              Use skb->cb for private data.
  69  *                               2000/03 Andi Kleen
  70  */
  71
  72 #include <linux/module.h>
  73 #include <linux/kernel.h>
  74 #include <linux/fcntl.h>
  75 #include <linux/mm.h>
  76 #include <linux/slab.h>
  77 #include <linux/string.h>
  78 #include <linux/errno.h>
  79 #include <linux/netdevice.h>
  80 #include <linux/etherdevice.h>
  81 #include <linux/skbuff.h>
  82 #include <linux/if_arp.h>
  83 #include <linux/init.h>
  84 #include <linux/if_shaper.h>
  85 #include <linux/jiffies.h>
  86
  87 #include <net/dst.h>
  88 #include <net/arp.h>
  89 #include <net/net_namespace.h>
  90
  91 struct shaper_cb {
  92         unsigned long   shapeclock;             /* Time it should go out */
  93         unsigned long   shapestamp;             /* Stamp for shaper    */
  94         __u32           shapelatency;           /* Latency on frame */
  95         __u32           shapelen;               /* Frame length in clocks */
  96         __u16           shapepend;              /* Pending */
  97 };
  98 #define SHAPERCB(skb) ((struct shaper_cb *) ((skb)->cb))
  99
 100 static int sh_debug;            /* Debug flag */
 101
 102 #define SHAPER_BANNER   "CymruNet Traffic Shaper BETA 0.04 for Linux 2.1\n"
 103
 104 static void shaper_kick(struct shaper *sh);
 105
 106 /*
 107  *      Compute clocks on a buffer
 108  */
 109
 110 static int shaper_clocks(struct shaper *shaper, struct sk_buff *skb)
 111 {
 112         int t=skb->len/shaper->bytespertick;
 113         return t;
 114 }
 115
 116 /*
 117  *      Set the speed of a shaper. We compute this in bytes per tick since
 118  *      thats how the machine wants to run. Quoted input is in bits per second
 119  *      as is traditional (note not BAUD). We assume 8 bit bytes.
 120  */
 121
 122 static void shaper_setspeed(struct shaper *shaper, int bitspersec)
 123 {
 124         shaper->bitspersec=bitspersec;
 125         shaper->bytespertick=(bitspersec/HZ)/8;
 126         if(!shaper->bytespertick)
 127                 shaper->bytespertick++;
 128 }
 129
 130 /*
 131  *      Throw a frame at a shaper.
 132  */
 133
 134
 135 static int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev)
 136 {
 137         struct shaper *shaper = dev->priv;
 138         struct sk_buff *ptr;
 139
 140         spin_lock(&shaper->lock);
 141         ptr=shaper->sendq.prev;
 142
 143         /*
 144          *      Set up our packet details
 145          */
 146
 147         SHAPERCB(skb)->shapelatency=0;
 148         SHAPERCB(skb)->shapeclock=shaper->recovery;
 149         if(time_before(SHAPERCB(skb)->shapeclock, jiffies))
 150                 SHAPERCB(skb)->shapeclock=jiffies;
 151         skb->priority=0;        /* short term bug fix */
 152         SHAPERCB(skb)->shapestamp=jiffies;
 153
 154         /*
 155          *      Time slots for this packet.
 156          */
 157
 158         SHAPERCB(skb)->shapelen= shaper_clocks(shaper,skb);
 159
 160         {
 161                 struct sk_buff *tmp;
 162                 /*
 163                  *      Up our shape clock by the time pending on the queue
 164                  *      (Should keep this in the shaper as a variable..)
 165                  */
 166                 for(tmp=skb_peek(&shaper->sendq); tmp!=NULL &&
 167                         tmp!=(struct sk_buff *)&shaper->sendq; tmp=tmp->next)
 168                         SHAPERCB(skb)->shapeclock+=SHAPERCB(tmp)->shapelen;
 169                 /*
 170                  *      Queue over time. Spill packet.
 171                  */
 172                 if(time_after(SHAPERCB(skb)->shapeclock,jiffies + SHAPER_LATENCY)) {
 173                         dev_kfree_skb(skb);
 174                         dev->stats.tx_dropped++;
 175                 } else
 176                         skb_queue_tail(&shaper->sendq, skb);
 177         }
 178
 179         if(sh_debug)
 180                 printk("Frame queued.\n");
 181         if(skb_queue_len(&shaper->sendq)>SHAPER_QLEN)
 182         {
 183                 ptr=skb_dequeue(&shaper->sendq);
 184                 dev_kfree_skb(ptr);
 185                 dev->stats.collisions++;
 186         }
 187         shaper_kick(shaper);
 188         spin_unlock(&shaper->lock);
 189         return 0;
 190 }
 191
 192 /*
 193  *      Transmit from a shaper
 194  */
 195
 196 static void shaper_queue_xmit(struct shaper *shaper, struct sk_buff *skb)
 197 {
 198         struct sk_buff *newskb=skb_clone(skb, GFP_ATOMIC);
 199         if(sh_debug)
 200                 printk("Kick frame on %p\n",newskb);
 201         if(newskb)
 202         {
 203                 newskb->dev=shaper->dev;
 204                 newskb->priority=2;
 205                 if(sh_debug)
 206                         printk("Kick new frame to %s, %d\n",
 207                                 shaper->dev->name,newskb->priority);
 208                 dev_queue_xmit(newskb);
 209
 210                 shaper->dev->stats.tx_bytes += skb->len;
 211                 shaper->dev->stats.tx_packets++;
 212
 213                 if(sh_debug)
 214                         printk("Kicked new frame out.\n");
 215                 dev_kfree_skb(skb);
 216         }
 217 }
 218
 219 /*
 220  *      Timer handler for shaping clock
 221  */
 222
 223 static void shaper_timer(unsigned long data)
 224 {
 225         struct shaper *shaper = (struct shaper *)data;
 226
 227         spin_lock(&shaper->lock);
 228         shaper_kick(shaper);
 229         spin_unlock(&shaper->lock);
 230 }
 231
 232 /*
 233  *      Kick a shaper queue and try and do something sensible with the
 234  *      queue.
 235  */
 236
 237 static void shaper_kick(struct shaper *shaper)
 238 {
 239         struct sk_buff *skb;
 240
 241         /*
 242          *      Walk the list (may be empty)
 243          */
 244
 245         while((skb=skb_peek(&shaper->sendq))!=NULL)
 246         {
 247                 /*
 248                  *      Each packet due to go out by now (within an error
 249                  *      of SHAPER_BURST) gets kicked onto the link
 250                  */
 251
 252                 if(sh_debug)
 253                         printk("Clock = %ld, jiffies = %ld\n", SHAPERCB(skb)->shapeclock, jiffies);
 254                 if(time_before_eq(SHAPERCB(skb)->shapeclock, jiffies + SHAPER_BURST))
 255                 {
 256                         /*
 257                          *      Pull the frame and get interrupts back on.
 258                          */
 259
 260                         skb_unlink(skb, &shaper->sendq);
 261                         if (shaper->recovery <
 262                             SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen)
 263                                 shaper->recovery = SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen;
 264                         /*
 265                          *      Pass on to the physical target device via
 266                          *      our low level packet thrower.
 267                          */
 268
 269                         SHAPERCB(skb)->shapepend=0;
 270                         shaper_queue_xmit(shaper, skb); /* Fire */
 271                 }
 272                 else
 273                         break;
 274         }
 275
 276         /*
 277          *      Next kick.
 278          */
 279
 280         if(skb!=NULL)
 281                 mod_timer(&shaper->timer, SHAPERCB(skb)->shapeclock);
 282 }
 283
 284
 285 /*
 286  *      Bring the interface up. We just disallow this until a
 287  *      bind.
 288  */
 289
 290 static int shaper_open(struct net_device *dev)
 291 {
 292         struct shaper *shaper=dev->priv;
 293
 294         /*
 295          *      Can't open until attached.
 296          *      Also can't open until speed is set, or we'll get
 297          *      a division by zero.
 298          */
 299
 300         if(shaper->dev==NULL)
 301                 return -ENODEV;
 302         if(shaper->bitspersec==0)
 303                 return -EINVAL;
 304         return 0;
 305 }
 306
 307 /*
 308  *      Closing a shaper flushes the queues.
 309  */
 310
 311 static int shaper_close(struct net_device *dev)
 312 {
 313         struct shaper *shaper=dev->priv;
 314         struct sk_buff *skb;
 315
 316         while ((skb = skb_dequeue(&shaper->sendq)) != NULL)
 317                 dev_kfree_skb(skb);
 318
 319         spin_lock_bh(&shaper->lock);
 320         shaper_kick(shaper);
 321         spin_unlock_bh(&shaper->lock);
 322
 323         del_timer_sync(&shaper->timer);
 324         return 0;
 325 }
 326
 327 /*
 328  *      Revectored calls. We alter the parameters and call the functions
 329  *      for our attached device. This enables us to bandwidth allocate after
 330  *      ARP and other resolutions and not before.
 331  */
 332
 333 static int shaper_header(struct sk_buff *skb, struct net_device *dev,
 334                          unsigned short type,
 335                          const void *daddr, const void *saddr, unsigned len)
 336 {
 337         struct shaper *sh=dev->priv;
 338         int v;
 339         if(sh_debug)
 340                 printk("Shaper header\n");
 341         skb->dev = sh->dev;
 342         v = dev_hard_header(skb, sh->dev, type, daddr, saddr, len);
 343         skb->dev = dev;
 344         return v;
 345 }
 346
 347 static int shaper_rebuild_header(struct sk_buff *skb)
 348 {
 349         struct shaper *sh=skb->dev->priv;
 350         struct net_device *dev=skb->dev;
 351         int v;
 352         if(sh_debug)
 353                 printk("Shaper rebuild header\n");
 354         skb->dev=sh->dev;
 355         v = sh->dev->header_ops->rebuild(skb);
 356         skb->dev=dev;
 357         return v;
 358 }
 359
 360 #if 0
 361 static int shaper_cache(struct neighbour *neigh, struct hh_cache *hh)
 362 {
 363         struct shaper *sh=neigh->dev->priv;
 364         struct net_device *tmp;
 365         int ret;
 366         if(sh_debug)
 367                 printk("Shaper header cache bind\n");
 368         tmp=neigh->dev;
 369         neigh->dev=sh->dev;
 370         ret=sh->hard_header_cache(neigh,hh);
 371         neigh->dev=tmp;
 372         return ret;
 373 }
 374
 375 static void shaper_cache_update(struct hh_cache *hh, struct net_device *dev,
 376         unsigned char *haddr)
 377 {
 378         struct shaper *sh=dev->priv;
 379         if(sh_debug)
 380                 printk("Shaper cache update\n");
 381         sh->header_cache_update(hh, sh->dev, haddr);
 382 }
 383 #endif
 384
 385 #ifdef CONFIG_INET
 386
 387 static int shaper_neigh_setup(struct neighbour *n)
 388 {
 389 #ifdef CONFIG_INET
 390         if (n->nud_state == NUD_NONE) {
 391                 n->ops = &arp_broken_ops;
 392                 n->output = n->ops->output;
 393         }
 394 #endif
 395         return 0;
 396 }
 397
 398 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 399 {
 400 #ifdef CONFIG_INET
 401         if (p->tbl->family == AF_INET) {
 402                 p->neigh_setup = shaper_neigh_setup;
 403                 p->ucast_probes = 0;
 404                 p->mcast_probes = 0;
 405         }
 406 #endif
 407         return 0;
 408 }
 409
 410 #else /* !(CONFIG_INET) */
 411
 412 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 413 {
 414         return 0;
 415 }
 416
 417 #endif
 418
 419 static const struct header_ops shaper_ops = {
 420         .create  = shaper_header,
 421         .rebuild = shaper_rebuild_header,
 422 };
 423
 424 static int shaper_attach(struct net_device *shdev, struct shaper *sh, struct net_device *dev)
 425 {
 426         sh->dev = dev;
 427         sh->get_stats=dev->get_stats;
 428
 429         shdev->neigh_setup = shaper_neigh_setup_dev;
 430         shdev->hard_header_len=dev->hard_header_len;
 431         shdev->type=dev->type;
 432         shdev->addr_len=dev->addr_len;
 433         shdev->mtu=dev->mtu;
 434         sh->bitspersec=0;
 435         return 0;
 436 }
 437
 438 static int shaper_ioctl(struct net_device *dev,  struct ifreq *ifr, int cmd)
 439 {
 440         struct shaperconf *ss= (struct shaperconf *)&ifr->ifr_ifru;
 441         struct shaper *sh=dev->priv;
 442
 443         if(ss->ss_cmd == SHAPER_SET_DEV || ss->ss_cmd == SHAPER_SET_SPEED)
 444         {
 445                 if(!capable(CAP_NET_ADMIN))
 446                         return -EPERM;
 447         }
 448
 449         switch(ss->ss_cmd)
 450         {
 451                 case SHAPER_SET_DEV:
 452                 {
 453                         struct net_device *them=__dev_get_by_name(&init_net, ss->ss_name);
 454                         if(them==NULL)
 455                                 return -ENODEV;
 456                         if(sh->dev)
 457                                 return -EBUSY;
 458                         return shaper_attach(dev,dev->priv, them);
 459                 }
 460                 case SHAPER_GET_DEV:
 461                         if(sh->dev==NULL)
 462                                 return -ENODEV;
 463                         strcpy(ss->ss_name, sh->dev->name);
 464                         return 0;
 465                 case SHAPER_SET_SPEED:
 466                         shaper_setspeed(sh,ss->ss_speed);
 467                         return 0;
 468                 case SHAPER_GET_SPEED:
 469                         ss->ss_speed=sh->bitspersec;
 470                         return 0;
 471                 default:
 472                         return -EINVAL;
 473         }
 474 }
 475
 476 static void shaper_init_priv(struct net_device *dev)
 477 {
 478         struct shaper *sh = dev->priv;
 479
 480         skb_queue_head_init(&sh->sendq);
 481         init_timer(&sh->timer);
 482         sh->timer.function=shaper_timer;
 483         sh->timer.data=(unsigned long)sh;
 484         spin_lock_init(&sh->lock);
 485 }
 486
 487 /*
 488  *      Add a shaper device to the system
 489  */
 490
 491 static void __init shaper_setup(struct net_device *dev)
 492 {
 493         /*
 494          *      Set up the shaper.
 495          */
 496
 497         shaper_init_priv(dev);
 498
 499         dev->open               = shaper_open;
 500         dev->stop               = shaper_close;
 501         dev->hard_start_xmit    = shaper_start_xmit;
 502         dev->set_multicast_list = NULL;
 503
 504         /*
 505          *      Intialise the packet queues
 506          */
 507
 508         /*
 509          *      Handlers for when we attach to a device.
 510          */
 511
 512         dev->neigh_setup        = shaper_neigh_setup_dev;
 513         dev->do_ioctl           = shaper_ioctl;
 514         dev->hard_header_len    = 0;
 515         dev->type               = ARPHRD_ETHER; /* initially */
 516         dev->set_mac_address    = NULL;
 517         dev->mtu                = 1500;
 518         dev->addr_len           = 0;
 519         dev->tx_queue_len       = 10;
 520         dev->flags              = 0;
 521 }
 522
 523 static int shapers = 1;
 524 #ifdef MODULE
 525
 526 module_param(shapers, int, 0);
 527 MODULE_PARM_DESC(shapers, "Traffic shaper: maximum number of shapers");
 528
 529 #else /* MODULE */
 530
 531 static int __init set_num_shapers(char *str)
 532 {
 533         shapers = simple_strtol(str, NULL, 0);
 534         return 1;
 535 }
 536
 537 __setup("shapers=", set_num_shapers);
 538
 539 #endif /* MODULE */
 540
 541 static struct net_device **devs;
 542
 543 static unsigned int shapers_registered = 0;
 544
 545 static int __init shaper_init(void)
 546 {
 547         int i;
 548         size_t alloc_size;
 549         struct net_device *dev;
 550         char name[IFNAMSIZ];
 551
 552         if (shapers < 1)
 553                 return -ENODEV;
 554
 555         alloc_size = sizeof(*dev) * shapers;
 556         devs = kzalloc(alloc_size, GFP_KERNEL);
 557         if (!devs)
 558                 return -ENOMEM;
 559
 560         for (i = 0; i < shapers; i++) {
 561
 562                 snprintf(name, IFNAMSIZ, "shaper%d", i);
 563                 dev = alloc_netdev(sizeof(struct shaper), name,
 564                                    shaper_setup);
 565                 if (!dev)
 566                         break;
 567
 568                 if (register_netdev(dev)) {
 569                         free_netdev(dev);
 570                         break;
 571                 }
 572
 573                 devs[i] = dev;
 574                 shapers_registered++;
 575         }
 576
 577         if (!shapers_registered) {
 578                 kfree(devs);
 579                 devs = NULL;
 580         }
 581
 582         return (shapers_registered ? 0 : -ENODEV);
 583 }
 584
 585 static void __exit shaper_exit (void)
 586 {
 587         int i;
 588
 589         for (i = 0; i < shapers_registered; i++) {
 590                 if (devs[i]) {
 591                         unregister_netdev(devs[i]);
 592                         free_netdev(devs[i]);
 593                 }
 594         }
 595
 596         kfree(devs);
 597         devs = NULL;
 598 }
 599
 600 module_init(shaper_init);
 601 module_exit(shaper_exit);
 602 MODULE_LICENSE("GPL");
 603