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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/config.h>
  73 #include <linux/module.h>
  74 #include <linux/kernel.h>
  75 #include <linux/fcntl.h>
  76 #include <linux/mm.h>
  77 #include <linux/slab.h>
  78 #include <linux/string.h>
  79 #include <linux/errno.h>
  80 #include <linux/netdevice.h>
  81 #include <linux/etherdevice.h>
  82 #include <linux/skbuff.h>
  83 #include <linux/if_arp.h>
  84 #include <linux/init.h>
  85 #include <linux/if_shaper.h>
  86
  87 #include <net/dst.h>
  88 #include <net/arp.h>
  89
  90 struct shaper_cb {
  91         unsigned long   shapeclock;             /* Time it should go out */
  92         unsigned long   shapestamp;             /* Stamp for shaper    */
  93         __u32           shapelatency;           /* Latency on frame */
  94         __u32           shapelen;               /* Frame length in clocks */
  95         __u16           shapepend;              /* Pending */
  96 };
  97 #define SHAPERCB(skb) ((struct shaper_cb *) ((skb)->cb))
  98
  99 static int sh_debug;            /* Debug flag */
 100
 101 #define SHAPER_BANNER   "CymruNet Traffic Shaper BETA 0.04 for Linux 2.1\n"
 102
 103 static void shaper_kick(struct shaper *sh);
 104
 105 /*
 106  *      Compute clocks on a buffer
 107  */
 108
 109 static int shaper_clocks(struct shaper *shaper, struct sk_buff *skb)
 110 {
 111         int t=skb->len/shaper->bytespertick;
 112         return t;
 113 }
 114
 115 /*
 116  *      Set the speed of a shaper. We compute this in bytes per tick since
 117  *      thats how the machine wants to run. Quoted input is in bits per second
 118  *      as is traditional (note not BAUD). We assume 8 bit bytes.
 119  */
 120
 121 static void shaper_setspeed(struct shaper *shaper, int bitspersec)
 122 {
 123         shaper->bitspersec=bitspersec;
 124         shaper->bytespertick=(bitspersec/HZ)/8;
 125         if(!shaper->bytespertick)
 126                 shaper->bytespertick++;
 127 }
 128
 129 /*
 130  *      Throw a frame at a shaper.
 131  */
 132
 133
 134 static int shaper_start_xmit(struct sk_buff *skb, struct net_device *dev)
 135 {
 136         struct shaper *shaper = dev->priv;
 137         struct sk_buff *ptr;
 138
 139         spin_lock(&shaper->lock);
 140         ptr=shaper->sendq.prev;
 141
 142         /*
 143          *      Set up our packet details
 144          */
 145
 146         SHAPERCB(skb)->shapelatency=0;
 147         SHAPERCB(skb)->shapeclock=shaper->recovery;
 148         if(time_before(SHAPERCB(skb)->shapeclock, jiffies))
 149                 SHAPERCB(skb)->shapeclock=jiffies;
 150         skb->priority=0;        /* short term bug fix */
 151         SHAPERCB(skb)->shapestamp=jiffies;
 152
 153         /*
 154          *      Time slots for this packet.
 155          */
 156
 157         SHAPERCB(skb)->shapelen= shaper_clocks(shaper,skb);
 158
 159 #ifdef SHAPER_COMPLEX /* and broken.. */
 160
 161         while(ptr && ptr!=(struct sk_buff *)&shaper->sendq)
 162         {
 163                 if(ptr->pri<skb->pri
 164                         && jiffies - SHAPERCB(ptr)->shapeclock < SHAPER_MAXSLIP)
 165                 {
 166                         struct sk_buff *tmp=ptr->prev;
 167
 168                         /*
 169                          *      It goes before us therefore we slip the length
 170                          *      of the new frame.
 171                          */
 172
 173                         SHAPERCB(ptr)->shapeclock+=SHAPERCB(skb)->shapelen;
 174                         SHAPERCB(ptr)->shapelatency+=SHAPERCB(skb)->shapelen;
 175
 176                         /*
 177                          *      The packet may have slipped so far back it
 178                          *      fell off.
 179                          */
 180                         if(SHAPERCB(ptr)->shapelatency > SHAPER_LATENCY)
 181                         {
 182                                 skb_unlink(ptr);
 183                                 dev_kfree_skb(ptr);
 184                         }
 185                         ptr=tmp;
 186                 }
 187                 else
 188                         break;
 189         }
 190         if(ptr==NULL || ptr==(struct sk_buff *)&shaper->sendq)
 191                 skb_queue_head(&shaper->sendq,skb);
 192         else
 193         {
 194                 struct sk_buff *tmp;
 195                 /*
 196                  *      Set the packet clock out time according to the
 197                  *      frames ahead. Im sure a bit of thought could drop
 198                  *      this loop.
 199                  */
 200                 for(tmp=skb_peek(&shaper->sendq); tmp!=NULL && tmp!=ptr; tmp=tmp->next)
 201                         SHAPERCB(skb)->shapeclock+=tmp->shapelen;
 202                 skb_append(ptr,skb);
 203         }
 204 #else
 205         {
 206                 struct sk_buff *tmp;
 207                 /*
 208                  *      Up our shape clock by the time pending on the queue
 209                  *      (Should keep this in the shaper as a variable..)
 210                  */
 211                 for(tmp=skb_peek(&shaper->sendq); tmp!=NULL &&
 212                         tmp!=(struct sk_buff *)&shaper->sendq; tmp=tmp->next)
 213                         SHAPERCB(skb)->shapeclock+=SHAPERCB(tmp)->shapelen;
 214                 /*
 215                  *      Queue over time. Spill packet.
 216                  */
 217                 if(SHAPERCB(skb)->shapeclock-jiffies > SHAPER_LATENCY) {
 218                         dev_kfree_skb(skb);
 219                         shaper->stats.tx_dropped++;
 220                 } else
 221                         skb_queue_tail(&shaper->sendq, skb);
 222         }
 223 #endif
 224         if(sh_debug)
 225                 printk("Frame queued.\n");
 226         if(skb_queue_len(&shaper->sendq)>SHAPER_QLEN)
 227         {
 228                 ptr=skb_dequeue(&shaper->sendq);
 229                 dev_kfree_skb(ptr);
 230                 shaper->stats.collisions++;
 231         }
 232         shaper_kick(shaper);
 233         spin_unlock(&shaper->lock);
 234         return 0;
 235 }
 236
 237 /*
 238  *      Transmit from a shaper
 239  */
 240
 241 static void shaper_queue_xmit(struct shaper *shaper, struct sk_buff *skb)
 242 {
 243         struct sk_buff *newskb=skb_clone(skb, GFP_ATOMIC);
 244         if(sh_debug)
 245                 printk("Kick frame on %p\n",newskb);
 246         if(newskb)
 247         {
 248                 newskb->dev=shaper->dev;
 249                 newskb->priority=2;
 250                 if(sh_debug)
 251                         printk("Kick new frame to %s, %d\n",
 252                                 shaper->dev->name,newskb->priority);
 253                 dev_queue_xmit(newskb);
 254
 255                 shaper->stats.tx_bytes += skb->len;
 256                 shaper->stats.tx_packets++;
 257
 258                 if(sh_debug)
 259                         printk("Kicked new frame out.\n");
 260                 dev_kfree_skb(skb);
 261         }
 262 }
 263
 264 /*
 265  *      Timer handler for shaping clock
 266  */
 267
 268 static void shaper_timer(unsigned long data)
 269 {
 270         struct shaper *shaper = (struct shaper *)data;
 271
 272         spin_lock(&shaper->lock);
 273         shaper_kick(shaper);
 274         spin_unlock(&shaper->lock);
 275 }
 276
 277 /*
 278  *      Kick a shaper queue and try and do something sensible with the
 279  *      queue.
 280  */
 281
 282 static void shaper_kick(struct shaper *shaper)
 283 {
 284         struct sk_buff *skb;
 285
 286         /*
 287          *      Walk the list (may be empty)
 288          */
 289
 290         while((skb=skb_peek(&shaper->sendq))!=NULL)
 291         {
 292                 /*
 293                  *      Each packet due to go out by now (within an error
 294                  *      of SHAPER_BURST) gets kicked onto the link
 295                  */
 296
 297                 if(sh_debug)
 298                         printk("Clock = %ld, jiffies = %ld\n", SHAPERCB(skb)->shapeclock, jiffies);
 299                 if(time_before_eq(SHAPERCB(skb)->shapeclock, jiffies + SHAPER_BURST))
 300                 {
 301                         /*
 302                          *      Pull the frame and get interrupts back on.
 303                          */
 304
 305                         skb_unlink(skb);
 306                         if (shaper->recovery <
 307                             SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen)
 308                                 shaper->recovery = SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen;
 309                         /*
 310                          *      Pass on to the physical target device via
 311                          *      our low level packet thrower.
 312                          */
 313
 314                         SHAPERCB(skb)->shapepend=0;
 315                         shaper_queue_xmit(shaper, skb); /* Fire */
 316                 }
 317                 else
 318                         break;
 319         }
 320
 321         /*
 322          *      Next kick.
 323          */
 324
 325         if(skb!=NULL)
 326                 mod_timer(&shaper->timer, SHAPERCB(skb)->shapeclock);
 327 }
 328
 329
 330 /*
 331  *      Bring the interface up. We just disallow this until a
 332  *      bind.
 333  */
 334
 335 static int shaper_open(struct net_device *dev)
 336 {
 337         struct shaper *shaper=dev->priv;
 338
 339         /*
 340          *      Can't open until attached.
 341          *      Also can't open until speed is set, or we'll get
 342          *      a division by zero.
 343          */
 344
 345         if(shaper->dev==NULL)
 346                 return -ENODEV;
 347         if(shaper->bitspersec==0)
 348                 return -EINVAL;
 349         return 0;
 350 }
 351
 352 /*
 353  *      Closing a shaper flushes the queues.
 354  */
 355
 356 static int shaper_close(struct net_device *dev)
 357 {
 358         struct shaper *shaper=dev->priv;
 359         struct sk_buff *skb;
 360
 361         while ((skb = skb_dequeue(&shaper->sendq)) != NULL)
 362                 dev_kfree_skb(skb);
 363
 364         spin_lock_bh(&shaper->lock);
 365         shaper_kick(shaper);
 366         spin_unlock_bh(&shaper->lock);
 367
 368         del_timer_sync(&shaper->timer);
 369         return 0;
 370 }
 371
 372 /*
 373  *      Revectored calls. We alter the parameters and call the functions
 374  *      for our attached device. This enables us to bandwidth allocate after
 375  *      ARP and other resolutions and not before.
 376  */
 377
 378 static struct net_device_stats *shaper_get_stats(struct net_device *dev)
 379 {
 380         struct shaper *sh=dev->priv;
 381         return &sh->stats;
 382 }
 383
 384 static int shaper_header(struct sk_buff *skb, struct net_device *dev,
 385         unsigned short type, void *daddr, void *saddr, unsigned len)
 386 {
 387         struct shaper *sh=dev->priv;
 388         int v;
 389         if(sh_debug)
 390                 printk("Shaper header\n");
 391         skb->dev=sh->dev;
 392         v=sh->hard_header(skb,sh->dev,type,daddr,saddr,len);
 393         skb->dev=dev;
 394         return v;
 395 }
 396
 397 static int shaper_rebuild_header(struct sk_buff *skb)
 398 {
 399         struct shaper *sh=skb->dev->priv;
 400         struct net_device *dev=skb->dev;
 401         int v;
 402         if(sh_debug)
 403                 printk("Shaper rebuild header\n");
 404         skb->dev=sh->dev;
 405         v=sh->rebuild_header(skb);
 406         skb->dev=dev;
 407         return v;
 408 }
 409
 410 #if 0
 411 static int shaper_cache(struct neighbour *neigh, struct hh_cache *hh)
 412 {
 413         struct shaper *sh=neigh->dev->priv;
 414         struct net_device *tmp;
 415         int ret;
 416         if(sh_debug)
 417                 printk("Shaper header cache bind\n");
 418         tmp=neigh->dev;
 419         neigh->dev=sh->dev;
 420         ret=sh->hard_header_cache(neigh,hh);
 421         neigh->dev=tmp;
 422         return ret;
 423 }
 424
 425 static void shaper_cache_update(struct hh_cache *hh, struct net_device *dev,
 426         unsigned char *haddr)
 427 {
 428         struct shaper *sh=dev->priv;
 429         if(sh_debug)
 430                 printk("Shaper cache update\n");
 431         sh->header_cache_update(hh, sh->dev, haddr);
 432 }
 433 #endif
 434
 435 #ifdef CONFIG_INET
 436
 437 static int shaper_neigh_setup(struct neighbour *n)
 438 {
 439 #ifdef CONFIG_INET
 440         if (n->nud_state == NUD_NONE) {
 441                 n->ops = &arp_broken_ops;
 442                 n->output = n->ops->output;
 443         }
 444 #endif
 445         return 0;
 446 }
 447
 448 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 449 {
 450 #ifdef CONFIG_INET
 451         if (p->tbl->family == AF_INET) {
 452                 p->neigh_setup = shaper_neigh_setup;
 453                 p->ucast_probes = 0;
 454                 p->mcast_probes = 0;
 455         }
 456 #endif
 457         return 0;
 458 }
 459
 460 #else /* !(CONFIG_INET) */
 461
 462 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 463 {
 464         return 0;
 465 }
 466
 467 #endif
 468
 469 static int shaper_attach(struct net_device *shdev, struct shaper *sh, struct net_device *dev)
 470 {
 471         sh->dev = dev;
 472         sh->hard_start_xmit=dev->hard_start_xmit;
 473         sh->get_stats=dev->get_stats;
 474         if(dev->hard_header)
 475         {
 476                 sh->hard_header=dev->hard_header;
 477                 shdev->hard_header = shaper_header;
 478         }
 479         else
 480                 shdev->hard_header = NULL;
 481
 482         if(dev->rebuild_header)
 483         {
 484                 sh->rebuild_header      = dev->rebuild_header;
 485                 shdev->rebuild_header   = shaper_rebuild_header;
 486         }
 487         else
 488                 shdev->rebuild_header   = NULL;
 489
 490 #if 0
 491         if(dev->hard_header_cache)
 492         {
 493                 sh->hard_header_cache   = dev->hard_header_cache;
 494                 shdev->hard_header_cache= shaper_cache;
 495         }
 496         else
 497         {
 498                 shdev->hard_header_cache= NULL;
 499         }
 500
 501         if(dev->header_cache_update)
 502         {
 503                 sh->header_cache_update = dev->header_cache_update;
 504                 shdev->header_cache_update = shaper_cache_update;
 505         }
 506         else
 507                 shdev->header_cache_update= NULL;
 508 #else
 509         shdev->header_cache_update = NULL;
 510         shdev->hard_header_cache = NULL;
 511 #endif
 512         shdev->neigh_setup = shaper_neigh_setup_dev;
 513
 514         shdev->hard_header_len=dev->hard_header_len;
 515         shdev->type=dev->type;
 516         shdev->addr_len=dev->addr_len;
 517         shdev->mtu=dev->mtu;
 518         sh->bitspersec=0;
 519         return 0;
 520 }
 521
 522 static int shaper_ioctl(struct net_device *dev,  struct ifreq *ifr, int cmd)
 523 {
 524         struct shaperconf *ss= (struct shaperconf *)&ifr->ifr_ifru;
 525         struct shaper *sh=dev->priv;
 526
 527         if(ss->ss_cmd == SHAPER_SET_DEV || ss->ss_cmd == SHAPER_SET_SPEED)
 528         {
 529                 if(!capable(CAP_NET_ADMIN))
 530                         return -EPERM;
 531         }
 532
 533         switch(ss->ss_cmd)
 534         {
 535                 case SHAPER_SET_DEV:
 536                 {
 537                         struct net_device *them=__dev_get_by_name(ss->ss_name);
 538                         if(them==NULL)
 539                                 return -ENODEV;
 540                         if(sh->dev)
 541                                 return -EBUSY;
 542                         return shaper_attach(dev,dev->priv, them);
 543                 }
 544                 case SHAPER_GET_DEV:
 545                         if(sh->dev==NULL)
 546                                 return -ENODEV;
 547                         strcpy(ss->ss_name, sh->dev->name);
 548                         return 0;
 549                 case SHAPER_SET_SPEED:
 550                         shaper_setspeed(sh,ss->ss_speed);
 551                         return 0;
 552                 case SHAPER_GET_SPEED:
 553                         ss->ss_speed=sh->bitspersec;
 554                         return 0;
 555                 default:
 556                         return -EINVAL;
 557         }
 558 }
 559
 560 static void shaper_init_priv(struct net_device *dev)
 561 {
 562         struct shaper *sh = dev->priv;
 563
 564         skb_queue_head_init(&sh->sendq);
 565         init_timer(&sh->timer);
 566         sh->timer.function=shaper_timer;
 567         sh->timer.data=(unsigned long)sh;
 568         spin_lock_init(&sh->lock);
 569 }
 570
 571 /*
 572  *      Add a shaper device to the system
 573  */
 574
 575 static void __init shaper_setup(struct net_device *dev)
 576 {
 577         /*
 578          *      Set up the shaper.
 579          */
 580
 581         SET_MODULE_OWNER(dev);
 582
 583         shaper_init_priv(dev);
 584
 585         dev->open               = shaper_open;
 586         dev->stop               = shaper_close;
 587         dev->hard_start_xmit    = shaper_start_xmit;
 588         dev->get_stats          = shaper_get_stats;
 589         dev->set_multicast_list = NULL;
 590
 591         /*
 592          *      Intialise the packet queues
 593          */
 594
 595         /*
 596          *      Handlers for when we attach to a device.
 597          */
 598
 599         dev->hard_header        = shaper_header;
 600         dev->rebuild_header     = shaper_rebuild_header;
 601 #if 0
 602         dev->hard_header_cache  = shaper_cache;
 603         dev->header_cache_update= shaper_cache_update;
 604 #endif
 605         dev->neigh_setup        = shaper_neigh_setup_dev;
 606         dev->do_ioctl           = shaper_ioctl;
 607         dev->hard_header_len    = 0;
 608         dev->type               = ARPHRD_ETHER; /* initially */
 609         dev->set_mac_address    = NULL;
 610         dev->mtu                = 1500;
 611         dev->addr_len           = 0;
 612         dev->tx_queue_len       = 10;
 613         dev->flags              = 0;
 614 }
 615
 616 static int shapers = 1;
 617 #ifdef MODULE
 618
 619 module_param(shapers, int, 0);
 620 MODULE_PARM_DESC(shapers, "Traffic shaper: maximum number of shapers");
 621
 622 #else /* MODULE */
 623
 624 static int __init set_num_shapers(char *str)
 625 {
 626         shapers = simple_strtol(str, NULL, 0);
 627         return 1;
 628 }
 629
 630 __setup("shapers=", set_num_shapers);
 631
 632 #endif /* MODULE */
 633
 634 static struct net_device **devs;
 635
 636 static unsigned int shapers_registered = 0;
 637
 638 static int __init shaper_init(void)
 639 {
 640         int i;
 641         size_t alloc_size;
 642         struct net_device *dev;
 643         char name[IFNAMSIZ];
 644
 645         if (shapers < 1)
 646                 return -ENODEV;
 647
 648         alloc_size = sizeof(*dev) * shapers;
 649         devs = kmalloc(alloc_size, GFP_KERNEL);
 650         if (!devs)
 651                 return -ENOMEM;
 652         memset(devs, 0, alloc_size);
 653
 654         for (i = 0; i < shapers; i++) {
 655
 656                 snprintf(name, IFNAMSIZ, "shaper%d", i);
 657                 dev = alloc_netdev(sizeof(struct shaper), name,
 658                                    shaper_setup);
 659                 if (!dev)
 660                         break;
 661
 662                 if (register_netdev(dev)) {
 663                         free_netdev(dev);
 664                         break;
 665                 }
 666
 667                 devs[i] = dev;
 668                 shapers_registered++;
 669         }
 670
 671         if (!shapers_registered) {
 672                 kfree(devs);
 673                 devs = NULL;
 674         }
 675
 676         return (shapers_registered ? 0 : -ENODEV);
 677 }
 678
 679 static void __exit shaper_exit (void)
 680 {
 681         int i;
 682
 683         for (i = 0; i < shapers_registered; i++) {
 684                 if (devs[i]) {
 685                         unregister_netdev(devs[i]);
 686                         free_netdev(devs[i]);
 687                 }
 688         }
 689
 690         kfree(devs);
 691         devs = NULL;
 692 }
 693
 694 module_init(shaper_init);
 695 module_exit(shaper_exit);
 696 MODULE_LICENSE("GPL");
 697