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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         {
 160                 struct sk_buff *tmp;
 161                 /*
 162                  *      Up our shape clock by the time pending on the queue
 163                  *      (Should keep this in the shaper as a variable..)
 164                  */
 165                 for(tmp=skb_peek(&shaper->sendq); tmp!=NULL &&
 166                         tmp!=(struct sk_buff *)&shaper->sendq; tmp=tmp->next)
 167                         SHAPERCB(skb)->shapeclock+=SHAPERCB(tmp)->shapelen;
 168                 /*
 169                  *      Queue over time. Spill packet.
 170                  */
 171                 if(SHAPERCB(skb)->shapeclock-jiffies > SHAPER_LATENCY) {
 172                         dev_kfree_skb(skb);
 173                         shaper->stats.tx_dropped++;
 174                 } else
 175                         skb_queue_tail(&shaper->sendq, skb);
 176         }
 177
 178         if(sh_debug)
 179                 printk("Frame queued.\n");
 180         if(skb_queue_len(&shaper->sendq)>SHAPER_QLEN)
 181         {
 182                 ptr=skb_dequeue(&shaper->sendq);
 183                 dev_kfree_skb(ptr);
 184                 shaper->stats.collisions++;
 185         }
 186         shaper_kick(shaper);
 187         spin_unlock(&shaper->lock);
 188         return 0;
 189 }
 190
 191 /*
 192  *      Transmit from a shaper
 193  */
 194
 195 static void shaper_queue_xmit(struct shaper *shaper, struct sk_buff *skb)
 196 {
 197         struct sk_buff *newskb=skb_clone(skb, GFP_ATOMIC);
 198         if(sh_debug)
 199                 printk("Kick frame on %p\n",newskb);
 200         if(newskb)
 201         {
 202                 newskb->dev=shaper->dev;
 203                 newskb->priority=2;
 204                 if(sh_debug)
 205                         printk("Kick new frame to %s, %d\n",
 206                                 shaper->dev->name,newskb->priority);
 207                 dev_queue_xmit(newskb);
 208
 209                 shaper->stats.tx_bytes += skb->len;
 210                 shaper->stats.tx_packets++;
 211
 212                 if(sh_debug)
 213                         printk("Kicked new frame out.\n");
 214                 dev_kfree_skb(skb);
 215         }
 216 }
 217
 218 /*
 219  *      Timer handler for shaping clock
 220  */
 221
 222 static void shaper_timer(unsigned long data)
 223 {
 224         struct shaper *shaper = (struct shaper *)data;
 225
 226         spin_lock(&shaper->lock);
 227         shaper_kick(shaper);
 228         spin_unlock(&shaper->lock);
 229 }
 230
 231 /*
 232  *      Kick a shaper queue and try and do something sensible with the
 233  *      queue.
 234  */
 235
 236 static void shaper_kick(struct shaper *shaper)
 237 {
 238         struct sk_buff *skb;
 239
 240         /*
 241          *      Walk the list (may be empty)
 242          */
 243
 244         while((skb=skb_peek(&shaper->sendq))!=NULL)
 245         {
 246                 /*
 247                  *      Each packet due to go out by now (within an error
 248                  *      of SHAPER_BURST) gets kicked onto the link
 249                  */
 250
 251                 if(sh_debug)
 252                         printk("Clock = %ld, jiffies = %ld\n", SHAPERCB(skb)->shapeclock, jiffies);
 253                 if(time_before_eq(SHAPERCB(skb)->shapeclock, jiffies + SHAPER_BURST))
 254                 {
 255                         /*
 256                          *      Pull the frame and get interrupts back on.
 257                          */
 258
 259                         skb_unlink(skb, &shaper->sendq);
 260                         if (shaper->recovery <
 261                             SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen)
 262                                 shaper->recovery = SHAPERCB(skb)->shapeclock + SHAPERCB(skb)->shapelen;
 263                         /*
 264                          *      Pass on to the physical target device via
 265                          *      our low level packet thrower.
 266                          */
 267
 268                         SHAPERCB(skb)->shapepend=0;
 269                         shaper_queue_xmit(shaper, skb); /* Fire */
 270                 }
 271                 else
 272                         break;
 273         }
 274
 275         /*
 276          *      Next kick.
 277          */
 278
 279         if(skb!=NULL)
 280                 mod_timer(&shaper->timer, SHAPERCB(skb)->shapeclock);
 281 }
 282
 283
 284 /*
 285  *      Bring the interface up. We just disallow this until a
 286  *      bind.
 287  */
 288
 289 static int shaper_open(struct net_device *dev)
 290 {
 291         struct shaper *shaper=dev->priv;
 292
 293         /*
 294          *      Can't open until attached.
 295          *      Also can't open until speed is set, or we'll get
 296          *      a division by zero.
 297          */
 298
 299         if(shaper->dev==NULL)
 300                 return -ENODEV;
 301         if(shaper->bitspersec==0)
 302                 return -EINVAL;
 303         return 0;
 304 }
 305
 306 /*
 307  *      Closing a shaper flushes the queues.
 308  */
 309
 310 static int shaper_close(struct net_device *dev)
 311 {
 312         struct shaper *shaper=dev->priv;
 313         struct sk_buff *skb;
 314
 315         while ((skb = skb_dequeue(&shaper->sendq)) != NULL)
 316                 dev_kfree_skb(skb);
 317
 318         spin_lock_bh(&shaper->lock);
 319         shaper_kick(shaper);
 320         spin_unlock_bh(&shaper->lock);
 321
 322         del_timer_sync(&shaper->timer);
 323         return 0;
 324 }
 325
 326 /*
 327  *      Revectored calls. We alter the parameters and call the functions
 328  *      for our attached device. This enables us to bandwidth allocate after
 329  *      ARP and other resolutions and not before.
 330  */
 331
 332 static struct net_device_stats *shaper_get_stats(struct net_device *dev)
 333 {
 334         struct shaper *sh=dev->priv;
 335         return &sh->stats;
 336 }
 337
 338 static int shaper_header(struct sk_buff *skb, struct net_device *dev,
 339         unsigned short type, void *daddr, void *saddr, unsigned len)
 340 {
 341         struct shaper *sh=dev->priv;
 342         int v;
 343         if(sh_debug)
 344                 printk("Shaper header\n");
 345         skb->dev=sh->dev;
 346         v=sh->hard_header(skb,sh->dev,type,daddr,saddr,len);
 347         skb->dev=dev;
 348         return v;
 349 }
 350
 351 static int shaper_rebuild_header(struct sk_buff *skb)
 352 {
 353         struct shaper *sh=skb->dev->priv;
 354         struct net_device *dev=skb->dev;
 355         int v;
 356         if(sh_debug)
 357                 printk("Shaper rebuild header\n");
 358         skb->dev=sh->dev;
 359         v=sh->rebuild_header(skb);
 360         skb->dev=dev;
 361         return v;
 362 }
 363
 364 #if 0
 365 static int shaper_cache(struct neighbour *neigh, struct hh_cache *hh)
 366 {
 367         struct shaper *sh=neigh->dev->priv;
 368         struct net_device *tmp;
 369         int ret;
 370         if(sh_debug)
 371                 printk("Shaper header cache bind\n");
 372         tmp=neigh->dev;
 373         neigh->dev=sh->dev;
 374         ret=sh->hard_header_cache(neigh,hh);
 375         neigh->dev=tmp;
 376         return ret;
 377 }
 378
 379 static void shaper_cache_update(struct hh_cache *hh, struct net_device *dev,
 380         unsigned char *haddr)
 381 {
 382         struct shaper *sh=dev->priv;
 383         if(sh_debug)
 384                 printk("Shaper cache update\n");
 385         sh->header_cache_update(hh, sh->dev, haddr);
 386 }
 387 #endif
 388
 389 #ifdef CONFIG_INET
 390
 391 static int shaper_neigh_setup(struct neighbour *n)
 392 {
 393 #ifdef CONFIG_INET
 394         if (n->nud_state == NUD_NONE) {
 395                 n->ops = &arp_broken_ops;
 396                 n->output = n->ops->output;
 397         }
 398 #endif
 399         return 0;
 400 }
 401
 402 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 403 {
 404 #ifdef CONFIG_INET
 405         if (p->tbl->family == AF_INET) {
 406                 p->neigh_setup = shaper_neigh_setup;
 407                 p->ucast_probes = 0;
 408                 p->mcast_probes = 0;
 409         }
 410 #endif
 411         return 0;
 412 }
 413
 414 #else /* !(CONFIG_INET) */
 415
 416 static int shaper_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 417 {
 418         return 0;
 419 }
 420
 421 #endif
 422
 423 static int shaper_attach(struct net_device *shdev, struct shaper *sh, struct net_device *dev)
 424 {
 425         sh->dev = dev;
 426         sh->hard_start_xmit=dev->hard_start_xmit;
 427         sh->get_stats=dev->get_stats;
 428         if(dev->hard_header)
 429         {
 430                 sh->hard_header=dev->hard_header;
 431                 shdev->hard_header = shaper_header;
 432         }
 433         else
 434                 shdev->hard_header = NULL;
 435
 436         if(dev->rebuild_header)
 437         {
 438                 sh->rebuild_header      = dev->rebuild_header;
 439                 shdev->rebuild_header   = shaper_rebuild_header;
 440         }
 441         else
 442                 shdev->rebuild_header   = NULL;
 443
 444 #if 0
 445         if(dev->hard_header_cache)
 446         {
 447                 sh->hard_header_cache   = dev->hard_header_cache;
 448                 shdev->hard_header_cache= shaper_cache;
 449         }
 450         else
 451         {
 452                 shdev->hard_header_cache= NULL;
 453         }
 454
 455         if(dev->header_cache_update)
 456         {
 457                 sh->header_cache_update = dev->header_cache_update;
 458                 shdev->header_cache_update = shaper_cache_update;
 459         }
 460         else
 461                 shdev->header_cache_update= NULL;
 462 #else
 463         shdev->header_cache_update = NULL;
 464         shdev->hard_header_cache = NULL;
 465 #endif
 466         shdev->neigh_setup = shaper_neigh_setup_dev;
 467
 468         shdev->hard_header_len=dev->hard_header_len;
 469         shdev->type=dev->type;
 470         shdev->addr_len=dev->addr_len;
 471         shdev->mtu=dev->mtu;
 472         sh->bitspersec=0;
 473         return 0;
 474 }
 475
 476 static int shaper_ioctl(struct net_device *dev,  struct ifreq *ifr, int cmd)
 477 {
 478         struct shaperconf *ss= (struct shaperconf *)&ifr->ifr_ifru;
 479         struct shaper *sh=dev->priv;
 480
 481         if(ss->ss_cmd == SHAPER_SET_DEV || ss->ss_cmd == SHAPER_SET_SPEED)
 482         {
 483                 if(!capable(CAP_NET_ADMIN))
 484                         return -EPERM;
 485         }
 486
 487         switch(ss->ss_cmd)
 488         {
 489                 case SHAPER_SET_DEV:
 490                 {
 491                         struct net_device *them=__dev_get_by_name(ss->ss_name);
 492                         if(them==NULL)
 493                                 return -ENODEV;
 494                         if(sh->dev)
 495                                 return -EBUSY;
 496                         return shaper_attach(dev,dev->priv, them);
 497                 }
 498                 case SHAPER_GET_DEV:
 499                         if(sh->dev==NULL)
 500                                 return -ENODEV;
 501                         strcpy(ss->ss_name, sh->dev->name);
 502                         return 0;
 503                 case SHAPER_SET_SPEED:
 504                         shaper_setspeed(sh,ss->ss_speed);
 505                         return 0;
 506                 case SHAPER_GET_SPEED:
 507                         ss->ss_speed=sh->bitspersec;
 508                         return 0;
 509                 default:
 510                         return -EINVAL;
 511         }
 512 }
 513
 514 static void shaper_init_priv(struct net_device *dev)
 515 {
 516         struct shaper *sh = dev->priv;
 517
 518         skb_queue_head_init(&sh->sendq);
 519         init_timer(&sh->timer);
 520         sh->timer.function=shaper_timer;
 521         sh->timer.data=(unsigned long)sh;
 522         spin_lock_init(&sh->lock);
 523 }
 524
 525 /*
 526  *      Add a shaper device to the system
 527  */
 528
 529 static void __init shaper_setup(struct net_device *dev)
 530 {
 531         /*
 532          *      Set up the shaper.
 533          */
 534
 535         SET_MODULE_OWNER(dev);
 536
 537         shaper_init_priv(dev);
 538
 539         dev->open               = shaper_open;
 540         dev->stop               = shaper_close;
 541         dev->hard_start_xmit    = shaper_start_xmit;
 542         dev->get_stats          = shaper_get_stats;
 543         dev->set_multicast_list = NULL;
 544
 545         /*
 546          *      Intialise the packet queues
 547          */
 548
 549         /*
 550          *      Handlers for when we attach to a device.
 551          */
 552
 553         dev->hard_header        = shaper_header;
 554         dev->rebuild_header     = shaper_rebuild_header;
 555 #if 0
 556         dev->hard_header_cache  = shaper_cache;
 557         dev->header_cache_update= shaper_cache_update;
 558 #endif
 559         dev->neigh_setup        = shaper_neigh_setup_dev;
 560         dev->do_ioctl           = shaper_ioctl;
 561         dev->hard_header_len    = 0;
 562         dev->type               = ARPHRD_ETHER; /* initially */
 563         dev->set_mac_address    = NULL;
 564         dev->mtu                = 1500;
 565         dev->addr_len           = 0;
 566         dev->tx_queue_len       = 10;
 567         dev->flags              = 0;
 568 }
 569
 570 static int shapers = 1;
 571 #ifdef MODULE
 572
 573 module_param(shapers, int, 0);
 574 MODULE_PARM_DESC(shapers, "Traffic shaper: maximum number of shapers");
 575
 576 #else /* MODULE */
 577
 578 static int __init set_num_shapers(char *str)
 579 {
 580         shapers = simple_strtol(str, NULL, 0);
 581         return 1;
 582 }
 583
 584 __setup("shapers=", set_num_shapers);
 585
 586 #endif /* MODULE */
 587
 588 static struct net_device **devs;
 589
 590 static unsigned int shapers_registered = 0;
 591
 592 static int __init shaper_init(void)
 593 {
 594         int i;
 595         size_t alloc_size;
 596         struct net_device *dev;
 597         char name[IFNAMSIZ];
 598
 599         if (shapers < 1)
 600                 return -ENODEV;
 601
 602         alloc_size = sizeof(*dev) * shapers;
 603         devs = kmalloc(alloc_size, GFP_KERNEL);
 604         if (!devs)
 605                 return -ENOMEM;
 606         memset(devs, 0, alloc_size);
 607
 608         for (i = 0; i < shapers; i++) {
 609
 610                 snprintf(name, IFNAMSIZ, "shaper%d", i);
 611                 dev = alloc_netdev(sizeof(struct shaper), name,
 612                                    shaper_setup);
 613                 if (!dev)
 614                         break;
 615
 616                 if (register_netdev(dev)) {
 617                         free_netdev(dev);
 618                         break;
 619                 }
 620
 621                 devs[i] = dev;
 622                 shapers_registered++;
 623         }
 624
 625         if (!shapers_registered) {
 626                 kfree(devs);
 627                 devs = NULL;
 628         }
 629
 630         return (shapers_registered ? 0 : -ENODEV);
 631 }
 632
 633 static void __exit shaper_exit (void)
 634 {
 635         int i;
 636
 637         for (i = 0; i < shapers_registered; i++) {
 638                 if (devs[i]) {
 639                         unregister_netdev(devs[i]);
 640                         free_netdev(devs[i]);
 641                 }
 642         }
 643
 644         kfree(devs);
 645         devs = NULL;
 646 }
 647
 648 module_init(shaper_init);
 649 module_exit(shaper_exit);
 650 MODULE_LICENSE("GPL");
 651