net/sched/sch_dsmark.c

   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/slab.h>
   9 #include <linux/types.h>
  10 #include <linux/string.h>
  11 #include <linux/errno.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/bitops.h>
  15 #include <net/pkt_sched.h>
  16 #include <net/dsfield.h>
  17 #include <net/inet_ecn.h>
  18 #include <asm/byteorder.h>
  19
  20 /*
  21  * classid      class           marking
  22  * -------      -----           -------
  23  *   n/a          0             n/a
  24  *   x:0          1             use entry [0]
  25  *   ...         ...            ...
  26  *   x:y y>0     y+1            use entry [y]
  27  *   ...         ...            ...
  28  * x:indices-1  indices         use entry [indices-1]
  29  *   ...         ...            ...
  30  *   x:y         y+1            use entry [y & (indices-1)]
  31  *   ...         ...            ...
  32  * 0xffff       0x10000         use entry [indices-1]
  33  */
  34
  35
  36 #define NO_DEFAULT_INDEX        (1 << 16)
  37
  38 struct dsmark_qdisc_data {
  39         struct Qdisc            *q;
  40         struct tcf_proto        *filter_list;
  41         u8                      *mask;  /* "owns" the array */
  42         u8                      *value;
  43         u16                     indices;
  44         u32                     default_index;  /* index range is 0...0xffff */
  45         int                     set_tc_index;
  46 };
  47
  48 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
  49 {
  50         return index <= p->indices && index > 0;
  51 }
  52
  53 /* ------------------------- Class/flow operations ------------------------- */
  54
  55 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
  56                         struct Qdisc *new, struct Qdisc **old)
  57 {
  58         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  59
  60         pr_debug("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
  61                 sch, p, new, old);
  62
  63         if (new == NULL) {
  64                 new = qdisc_create_dflt(sch->dev_queue, &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->q.qlen++;
 264
 265         return NET_XMIT_SUCCESS;
 266
 267 drop:
 268         qdisc_drop(skb, sch);
 269         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 270 }
 271
 272 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 273 {
 274         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 275         struct sk_buff *skb;
 276         u32 index;
 277
 278         pr_debug("dsmark_dequeue(sch %p,[qdisc %p])\n", sch, p);
 279
 280         skb = p->q->ops->dequeue(p->q);
 281         if (skb == NULL)
 282                 return NULL;
 283
 284         qdisc_bstats_update(sch, skb);
 285         sch->q.qlen--;
 286
 287         index = skb->tc_index & (p->indices - 1);
 288         pr_debug("index %d->%d\n", skb->tc_index, index);
 289
 290         switch (skb->protocol) {
 291         case htons(ETH_P_IP):
 292                 ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
 293                                     p->value[index]);
 294                         break;
 295         case htons(ETH_P_IPV6):
 296                 ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
 297                                     p->value[index]);
 298                         break;
 299         default:
 300                 /*
 301                  * Only complain if a change was actually attempted.
 302                  * This way, we can send non-IP traffic through dsmark
 303                  * and don't need yet another qdisc as a bypass.
 304                  */
 305                 if (p->mask[index] != 0xff || p->value[index])
 306                         pr_warn("dsmark_dequeue: unsupported protocol %d\n",
 307                                 ntohs(skb->protocol));
 308                 break;
 309         }
 310
 311         return skb;
 312 }
 313
 314 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 315 {
 316         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 317
 318         pr_debug("dsmark_peek(sch %p,[qdisc %p])\n", sch, p);
 319
 320         return p->q->ops->peek(p->q);
 321 }
 322
 323 static unsigned int dsmark_drop(struct Qdisc *sch)
 324 {
 325         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 326         unsigned int len;
 327
 328         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 329
 330         if (p->q->ops->drop == NULL)
 331                 return 0;
 332
 333         len = p->q->ops->drop(p->q);
 334         if (len)
 335                 sch->q.qlen--;
 336
 337         return len;
 338 }
 339
 340 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
 341 {
 342         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 343         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 344         int err = -EINVAL;
 345         u32 default_index = NO_DEFAULT_INDEX;
 346         u16 indices;
 347         u8 *mask;
 348
 349         pr_debug("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
 350
 351         if (!opt)
 352                 goto errout;
 353
 354         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 355         if (err < 0)
 356                 goto errout;
 357
 358         err = -EINVAL;
 359         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 360
 361         if (hweight32(indices) != 1)
 362                 goto errout;
 363
 364         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 365                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 366
 367         mask = kmalloc(indices * 2, GFP_KERNEL);
 368         if (mask == NULL) {
 369                 err = -ENOMEM;
 370                 goto errout;
 371         }
 372
 373         p->mask = mask;
 374         memset(p->mask, 0xff, indices);
 375
 376         p->value = p->mask + indices;
 377         memset(p->value, 0, indices);
 378
 379         p->indices = indices;
 380         p->default_index = default_index;
 381         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 382
 383         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle);
 384         if (p->q == NULL)
 385                 p->q = &noop_qdisc;
 386
 387         pr_debug("dsmark_init: qdisc %p\n", p->q);
 388
 389         err = 0;
 390 errout:
 391         return err;
 392 }
 393
 394 static void dsmark_reset(struct Qdisc *sch)
 395 {
 396         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 397
 398         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 399         qdisc_reset(p->q);
 400         sch->q.qlen = 0;
 401 }
 402
 403 static void dsmark_destroy(struct Qdisc *sch)
 404 {
 405         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 406
 407         pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
 408
 409         tcf_destroy_chain(&p->filter_list);
 410         qdisc_destroy(p->q);
 411         kfree(p->mask);
 412 }
 413
 414 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 415                              struct sk_buff *skb, struct tcmsg *tcm)
 416 {
 417         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 418         struct nlattr *opts = NULL;
 419
 420         pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
 421
 422         if (!dsmark_valid_index(p, cl))
 423                 return -EINVAL;
 424
 425         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 426         tcm->tcm_info = p->q->handle;
 427
 428         opts = nla_nest_start(skb, TCA_OPTIONS);
 429         if (opts == NULL)
 430                 goto nla_put_failure;
 431         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mask[cl - 1]) ||
 432             nla_put_u8(skb, TCA_DSMARK_VALUE, p->value[cl - 1]))
 433                 goto nla_put_failure;
 434
 435         return nla_nest_end(skb, opts);
 436
 437 nla_put_failure:
 438         nla_nest_cancel(skb, opts);
 439         return -EMSGSIZE;
 440 }
 441
 442 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 443 {
 444         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 445         struct nlattr *opts = NULL;
 446
 447         opts = nla_nest_start(skb, TCA_OPTIONS);
 448         if (opts == NULL)
 449                 goto nla_put_failure;
 450         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 451                 goto nla_put_failure;
 452
 453         if (p->default_index != NO_DEFAULT_INDEX &&
 454             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 455                 goto nla_put_failure;
 456
 457         if (p->set_tc_index &&
 458             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 459                 goto nla_put_failure;
 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");