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   1 /* net/sched/sch_dsmark.c - Differentiated Services field marker */
   2
   3 /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
   4
   5
   6 #include <linux/module.h>
   7 #include <linux/init.h>
   8 #include <linux/types.h>
   9 #include <linux/string.h>
  10 #include <linux/errno.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/rtnetlink.h>
  13 #include <linux/bitops.h>
  14 #include <net/pkt_sched.h>
  15 #include <net/dsfield.h>
  16 #include <net/inet_ecn.h>
  17 #include <asm/byteorder.h>
  18
  19 /*
  20  * classid      class           marking
  21  * -------      -----           -------
  22  *   n/a          0             n/a
  23  *   x:0          1             use entry [0]
  24  *   ...         ...            ...
  25  *   x:y y>0     y+1            use entry [y]
  26  *   ...         ...            ...
  27  * x:indices-1  indices         use entry [indices-1]
  28  *   ...         ...            ...
  29  *   x:y         y+1            use entry [y & (indices-1)]
  30  *   ...         ...            ...
  31  * 0xffff       0x10000         use entry [indices-1]
  32  */
  33
  34
  35 #define NO_DEFAULT_INDEX        (1 << 16)
  36
  37 struct dsmark_qdisc_data {
  38         struct Qdisc            *q;
  39         struct tcf_proto        *filter_list;
  40         u8                      *mask;  /* "owns" the array */
  41         u8                      *value;
  42         u16                     indices;
  43         u32                     default_index;  /* index range is 0...0xffff */
  44         int                     set_tc_index;
  45 };
  46
  47 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
  48 {
  49         return (index <= p->indices && index > 0);
  50 }
  51
  52 /* ------------------------- Class/flow operations ------------------------- */
  53
  54 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
  55                         struct Qdisc *new, struct Qdisc **old)
  56 {
  57         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  58
  59         pr_debug("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
  60                 sch, p, new, old);
  61
  62         if (new == NULL) {
  63                 new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
  64                                         &pfifo_qdisc_ops,
  65                                         sch->handle);
  66                 if (new == NULL)
  67                         new = &noop_qdisc;
  68         }
  69
  70         sch_tree_lock(sch);
  71         *old = p->q;
  72         p->q = new;
  73         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
  74         qdisc_reset(*old);
  75         sch_tree_unlock(sch);
  76
  77         return 0;
  78 }
  79
  80 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  81 {
  82         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  83         return p->q;
  84 }
  85
  86 static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
  87 {
  88         pr_debug("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
  89                 sch, qdisc_priv(sch), classid);
  90
  91         return TC_H_MIN(classid) + 1;
  92 }
  93
  94 static unsigned long dsmark_bind_filter(struct Qdisc *sch,
  95                                         unsigned long parent, u32 classid)
  96 {
  97         return dsmark_get(sch, classid);
  98 }
  99
 100 static void dsmark_put(struct Qdisc *sch, unsigned long cl)
 101 {
 102 }
 103
 104 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
 105         [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
 106         [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
 107         [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
 108         [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
 109         [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
 110 };
 111
 112 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
 113                          struct nlattr **tca, unsigned long *arg)
 114 {
 115         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 116         struct nlattr *opt = tca[TCA_OPTIONS];
 117         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 118         int err = -EINVAL;
 119         u8 mask = 0;
 120
 121         pr_debug("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
 122                 "arg 0x%lx\n", sch, p, classid, parent, *arg);
 123
 124         if (!dsmark_valid_index(p, *arg)) {
 125                 err = -ENOENT;
 126                 goto errout;
 127         }
 128
 129         if (!opt)
 130                 goto errout;
 131
 132         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 133         if (err < 0)
 134                 goto errout;
 135
 136         if (tb[TCA_DSMARK_MASK])
 137                 mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
 138
 139         if (tb[TCA_DSMARK_VALUE])
 140                 p->value[*arg-1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 141
 142         if (tb[TCA_DSMARK_MASK])
 143                 p->mask[*arg-1] = mask;
 144
 145         err = 0;
 146
 147 errout:
 148         return err;
 149 }
 150
 151 static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
 152 {
 153         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 154
 155         if (!dsmark_valid_index(p, arg))
 156                 return -EINVAL;
 157
 158         p->mask[arg-1] = 0xff;
 159         p->value[arg-1] = 0;
 160
 161         return 0;
 162 }
 163
 164 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 165 {
 166         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 167         int i;
 168
 169         pr_debug("dsmark_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
 170
 171         if (walker->stop)
 172                 return;
 173
 174         for (i = 0; i < p->indices; i++) {
 175                 if (p->mask[i] == 0xff && !p->value[i])
 176                         goto ignore;
 177                 if (walker->count >= walker->skip) {
 178                         if (walker->fn(sch, i+1, walker) < 0) {
 179                                 walker->stop = 1;
 180                                 break;
 181                         }
 182                 }
 183 ignore:
 184                 walker->count++;
 185         }
 186 }
 187
 188 static inline struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,
 189                                                  unsigned long cl)
 190 {
 191         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 192         return &p->filter_list;
 193 }
 194
 195 /* --------------------------- Qdisc operations ---------------------------- */
 196
 197 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 198 {
 199         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 200         int err;
 201
 202         pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
 203
 204         if (p->set_tc_index) {
 205                 switch (skb->protocol) {
 206                 case htons(ETH_P_IP):
 207                         if (skb_cow_head(skb, sizeof(struct iphdr)))
 208                                 goto drop;
 209
 210                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 211                                 & ~INET_ECN_MASK;
 212                         break;
 213
 214                 case htons(ETH_P_IPV6):
 215                         if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
 216                                 goto drop;
 217
 218                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 219                                 & ~INET_ECN_MASK;
 220                         break;
 221                 default:
 222                         skb->tc_index = 0;
 223                         break;
 224                 }
 225         }
 226
 227         if (TC_H_MAJ(skb->priority) == sch->handle)
 228                 skb->tc_index = TC_H_MIN(skb->priority);
 229         else {
 230                 struct tcf_result res;
 231                 int result = tc_classify(skb, p->filter_list, &res);
 232
 233                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 234
 235                 switch (result) {
 236 #ifdef CONFIG_NET_CLS_ACT
 237                 case TC_ACT_QUEUED:
 238                 case TC_ACT_STOLEN:
 239                         kfree_skb(skb);
 240                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 241
 242                 case TC_ACT_SHOT:
 243                         goto drop;
 244 #endif
 245                 case TC_ACT_OK:
 246                         skb->tc_index = TC_H_MIN(res.classid);
 247                         break;
 248
 249                 default:
 250                         if (p->default_index != NO_DEFAULT_INDEX)
 251                                 skb->tc_index = p->default_index;
 252                         break;
 253                 }
 254         }
 255
 256         err = qdisc_enqueue(skb, p->q);
 257         if (err != NET_XMIT_SUCCESS) {
 258                 if (net_xmit_drop_count(err))
 259                         sch->qstats.drops++;
 260                 return err;
 261         }
 262
 263         sch->bstats.bytes += qdisc_pkt_len(skb);
 264         sch->bstats.packets++;
 265         sch->q.qlen++;
 266
 267         return NET_XMIT_SUCCESS;
 268
 269 drop:
 270         kfree_skb(skb);
 271         sch->qstats.drops++;
 272         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 273 }
 274
 275 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 276 {
 277         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 278         struct sk_buff *skb;
 279         u32 index;
 280
 281         pr_debug("dsmark_dequeue(sch %p,[qdisc %p])\n", sch, p);
 282
 283         skb = p->q->ops->dequeue(p->q);
 284         if (skb == NULL)
 285                 return NULL;
 286
 287         sch->q.qlen--;
 288
 289         index = skb->tc_index & (p->indices - 1);
 290         pr_debug("index %d->%d\n", skb->tc_index, index);
 291
 292         switch (skb->protocol) {
 293         case htons(ETH_P_IP):
 294                 ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
 295                                     p->value[index]);
 296                         break;
 297         case htons(ETH_P_IPV6):
 298                 ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
 299                                     p->value[index]);
 300                         break;
 301         default:
 302                 /*
 303                  * Only complain if a change was actually attempted.
 304                  * This way, we can send non-IP traffic through dsmark
 305                  * and don't need yet another qdisc as a bypass.
 306                  */
 307                 if (p->mask[index] != 0xff || p->value[index])
 308                         printk(KERN_WARNING
 309                                "dsmark_dequeue: unsupported protocol %d\n",
 310                                ntohs(skb->protocol));
 311                 break;
 312         }
 313
 314         return skb;
 315 }
 316
 317 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 318 {
 319         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 320
 321         pr_debug("dsmark_peek(sch %p,[qdisc %p])\n", sch, p);
 322
 323         return p->q->ops->peek(p->q);
 324 }
 325
 326 static unsigned int dsmark_drop(struct Qdisc *sch)
 327 {
 328         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 329         unsigned int len;
 330
 331         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 332
 333         if (p->q->ops->drop == NULL)
 334                 return 0;
 335
 336         len = p->q->ops->drop(p->q);
 337         if (len)
 338                 sch->q.qlen--;
 339
 340         return len;
 341 }
 342
 343 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
 344 {
 345         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 346         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 347         int err = -EINVAL;
 348         u32 default_index = NO_DEFAULT_INDEX;
 349         u16 indices;
 350         u8 *mask;
 351
 352         pr_debug("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
 353
 354         if (!opt)
 355                 goto errout;
 356
 357         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 358         if (err < 0)
 359                 goto errout;
 360
 361         err = -EINVAL;
 362         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 363
 364         if (hweight32(indices) != 1)
 365                 goto errout;
 366
 367         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 368                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 369
 370         mask = kmalloc(indices * 2, GFP_KERNEL);
 371         if (mask == NULL) {
 372                 err = -ENOMEM;
 373                 goto errout;
 374         }
 375
 376         p->mask = mask;
 377         memset(p->mask, 0xff, indices);
 378
 379         p->value = p->mask + indices;
 380         memset(p->value, 0, indices);
 381
 382         p->indices = indices;
 383         p->default_index = default_index;
 384         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 385
 386         p->q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
 387                                  &pfifo_qdisc_ops, sch->handle);
 388         if (p->q == NULL)
 389                 p->q = &noop_qdisc;
 390
 391         pr_debug("dsmark_init: qdisc %p\n", p->q);
 392
 393         err = 0;
 394 errout:
 395         return err;
 396 }
 397
 398 static void dsmark_reset(struct Qdisc *sch)
 399 {
 400         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 401
 402         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 403         qdisc_reset(p->q);
 404         sch->q.qlen = 0;
 405 }
 406
 407 static void dsmark_destroy(struct Qdisc *sch)
 408 {
 409         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 410
 411         pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
 412
 413         tcf_destroy_chain(&p->filter_list);
 414         qdisc_destroy(p->q);
 415         kfree(p->mask);
 416 }
 417
 418 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 419                              struct sk_buff *skb, struct tcmsg *tcm)
 420 {
 421         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 422         struct nlattr *opts = NULL;
 423
 424         pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
 425
 426         if (!dsmark_valid_index(p, cl))
 427                 return -EINVAL;
 428
 429         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl-1);
 430         tcm->tcm_info = p->q->handle;
 431
 432         opts = nla_nest_start(skb, TCA_OPTIONS);
 433         if (opts == NULL)
 434                 goto nla_put_failure;
 435         NLA_PUT_U8(skb, TCA_DSMARK_MASK, p->mask[cl-1]);
 436         NLA_PUT_U8(skb, TCA_DSMARK_VALUE, p->value[cl-1]);
 437
 438         return nla_nest_end(skb, opts);
 439
 440 nla_put_failure:
 441         nla_nest_cancel(skb, opts);
 442         return -EMSGSIZE;
 443 }
 444
 445 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 446 {
 447         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 448         struct nlattr *opts = NULL;
 449
 450         opts = nla_nest_start(skb, TCA_OPTIONS);
 451         if (opts == NULL)
 452                 goto nla_put_failure;
 453         NLA_PUT_U16(skb, TCA_DSMARK_INDICES, p->indices);
 454
 455         if (p->default_index != NO_DEFAULT_INDEX)
 456                 NLA_PUT_U16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index);
 457
 458         if (p->set_tc_index)
 459                 NLA_PUT_FLAG(skb, TCA_DSMARK_SET_TC_INDEX);
 460
 461         return nla_nest_end(skb, opts);
 462
 463 nla_put_failure:
 464         nla_nest_cancel(skb, opts);
 465         return -EMSGSIZE;
 466 }
 467
 468 static const struct Qdisc_class_ops dsmark_class_ops = {
 469         .graft          =       dsmark_graft,
 470         .leaf           =       dsmark_leaf,
 471         .get            =       dsmark_get,
 472         .put            =       dsmark_put,
 473         .change         =       dsmark_change,
 474         .delete         =       dsmark_delete,
 475         .walk           =       dsmark_walk,
 476         .tcf_chain      =       dsmark_find_tcf,
 477         .bind_tcf       =       dsmark_bind_filter,
 478         .unbind_tcf     =       dsmark_put,
 479         .dump           =       dsmark_dump_class,
 480 };
 481
 482 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 483         .next           =       NULL,
 484         .cl_ops         =       &dsmark_class_ops,
 485         .id             =       "dsmark",
 486         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 487         .enqueue        =       dsmark_enqueue,
 488         .dequeue        =       dsmark_dequeue,
 489         .peek           =       dsmark_peek,
 490         .drop           =       dsmark_drop,
 491         .init           =       dsmark_init,
 492         .reset          =       dsmark_reset,
 493         .destroy        =       dsmark_destroy,
 494         .change         =       NULL,
 495         .dump           =       dsmark_dump,
 496         .owner          =       THIS_MODULE,
 497 };
 498
 499 static int __init dsmark_module_init(void)
 500 {
 501         return register_qdisc(&dsmark_qdisc_ops);
 502 }
 503
 504 static void __exit dsmark_module_exit(void)
 505 {
 506         unregister_qdisc(&dsmark_qdisc_ops);
 507 }
 508
 509 module_init(dsmark_module_init)
 510 module_exit(dsmark_module_exit)
 511
 512 MODULE_LICENSE("GPL");