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 __rcu  *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("%s(sch %p,[qdisc %p],new %p,old %p)\n",
  61                  __func__, 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("%s(sch %p,[qdisc %p],classid %x)\n",
  89                  __func__, 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("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",
 122                  __func__, 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("%s(sch %p,[qdisc %p],walker %p)\n",
 170                  __func__, sch, p, walker);
 171
 172         if (walker->stop)
 173                 return;
 174
 175         for (i = 0; i < p->indices; i++) {
 176                 if (p->mask[i] == 0xff && !p->value[i])
 177                         goto ignore;
 178                 if (walker->count >= walker->skip) {
 179                         if (walker->fn(sch, i + 1, walker) < 0) {
 180                                 walker->stop = 1;
 181                                 break;
 182                         }
 183                 }
 184 ignore:
 185                 walker->count++;
 186         }
 187 }
 188
 189 static inline struct tcf_proto __rcu **dsmark_find_tcf(struct Qdisc *sch,
 190                                                        unsigned long cl)
 191 {
 192         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 193         return &p->filter_list;
 194 }
 195
 196 /* --------------------------- Qdisc operations ---------------------------- */
 197
 198 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 199 {
 200         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 201         int err;
 202
 203         pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
 204
 205         if (p->set_tc_index) {
 206                 switch (tc_skb_protocol(skb)) {
 207                 case htons(ETH_P_IP):
 208                         if (skb_cow_head(skb, sizeof(struct iphdr)))
 209                                 goto drop;
 210
 211                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 212                                 & ~INET_ECN_MASK;
 213                         break;
 214
 215                 case htons(ETH_P_IPV6):
 216                         if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
 217                                 goto drop;
 218
 219                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 220                                 & ~INET_ECN_MASK;
 221                         break;
 222                 default:
 223                         skb->tc_index = 0;
 224                         break;
 225                 }
 226         }
 227
 228         if (TC_H_MAJ(skb->priority) == sch->handle)
 229                 skb->tc_index = TC_H_MIN(skb->priority);
 230         else {
 231                 struct tcf_result res;
 232                 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 233                 int result = tc_classify(skb, fl, &res, false);
 234
 235                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 236
 237                 switch (result) {
 238 #ifdef CONFIG_NET_CLS_ACT
 239                 case TC_ACT_QUEUED:
 240                 case TC_ACT_STOLEN:
 241                         kfree_skb(skb);
 242                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 243
 244                 case TC_ACT_SHOT:
 245                         goto drop;
 246 #endif
 247                 case TC_ACT_OK:
 248                         skb->tc_index = TC_H_MIN(res.classid);
 249                         break;
 250
 251                 default:
 252                         if (p->default_index != NO_DEFAULT_INDEX)
 253                                 skb->tc_index = p->default_index;
 254                         break;
 255                 }
 256         }
 257
 258         err = qdisc_enqueue(skb, p->q);
 259         if (err != NET_XMIT_SUCCESS) {
 260                 if (net_xmit_drop_count(err))
 261                         qdisc_qstats_drop(sch);
 262                 return err;
 263         }
 264
 265         sch->q.qlen++;
 266
 267         return NET_XMIT_SUCCESS;
 268
 269 drop:
 270         qdisc_drop(skb, sch);
 271         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 272 }
 273
 274 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 275 {
 276         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 277         struct sk_buff *skb;
 278         u32 index;
 279
 280         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 281
 282         skb = p->q->ops->dequeue(p->q);
 283         if (skb == NULL)
 284                 return NULL;
 285
 286         qdisc_bstats_update(sch, skb);
 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 (tc_skb_protocol(skb)) {
 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                         pr_warn("%s: unsupported protocol %d\n",
 309                                 __func__, ntohs(tc_skb_protocol(skb)));
 310                 break;
 311         }
 312
 313         return skb;
 314 }
 315
 316 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 317 {
 318         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 319
 320         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 321
 322         return p->q->ops->peek(p->q);
 323 }
 324
 325 static unsigned int dsmark_drop(struct Qdisc *sch)
 326 {
 327         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 328         unsigned int len;
 329
 330         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 331
 332         if (p->q->ops->drop == NULL)
 333                 return 0;
 334
 335         len = p->q->ops->drop(p->q);
 336         if (len)
 337                 sch->q.qlen--;
 338
 339         return len;
 340 }
 341
 342 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
 343 {
 344         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 345         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 346         int err = -EINVAL;
 347         u32 default_index = NO_DEFAULT_INDEX;
 348         u16 indices;
 349         u8 *mask;
 350
 351         pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
 352
 353         if (!opt)
 354                 goto errout;
 355
 356         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 357         if (err < 0)
 358                 goto errout;
 359
 360         err = -EINVAL;
 361         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 362
 363         if (hweight32(indices) != 1)
 364                 goto errout;
 365
 366         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 367                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 368
 369         mask = kmalloc(indices * 2, GFP_KERNEL);
 370         if (mask == NULL) {
 371                 err = -ENOMEM;
 372                 goto errout;
 373         }
 374
 375         p->mask = mask;
 376         memset(p->mask, 0xff, indices);
 377
 378         p->value = p->mask + indices;
 379         memset(p->value, 0, indices);
 380
 381         p->indices = indices;
 382         p->default_index = default_index;
 383         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 384
 385         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle);
 386         if (p->q == NULL)
 387                 p->q = &noop_qdisc;
 388
 389         pr_debug("%s: qdisc %p\n", __func__, p->q);
 390
 391         err = 0;
 392 errout:
 393         return err;
 394 }
 395
 396 static void dsmark_reset(struct Qdisc *sch)
 397 {
 398         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 399
 400         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 401         qdisc_reset(p->q);
 402         sch->q.qlen = 0;
 403 }
 404
 405 static void dsmark_destroy(struct Qdisc *sch)
 406 {
 407         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 408
 409         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 410
 411         tcf_destroy_chain(&p->filter_list);
 412         qdisc_destroy(p->q);
 413         kfree(p->mask);
 414 }
 415
 416 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 417                              struct sk_buff *skb, struct tcmsg *tcm)
 418 {
 419         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 420         struct nlattr *opts = NULL;
 421
 422         pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
 423
 424         if (!dsmark_valid_index(p, cl))
 425                 return -EINVAL;
 426
 427         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 428         tcm->tcm_info = p->q->handle;
 429
 430         opts = nla_nest_start(skb, TCA_OPTIONS);
 431         if (opts == NULL)
 432                 goto nla_put_failure;
 433         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mask[cl - 1]) ||
 434             nla_put_u8(skb, TCA_DSMARK_VALUE, p->value[cl - 1]))
 435                 goto nla_put_failure;
 436
 437         return nla_nest_end(skb, opts);
 438
 439 nla_put_failure:
 440         nla_nest_cancel(skb, opts);
 441         return -EMSGSIZE;
 442 }
 443
 444 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 445 {
 446         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 447         struct nlattr *opts = NULL;
 448
 449         opts = nla_nest_start(skb, TCA_OPTIONS);
 450         if (opts == NULL)
 451                 goto nla_put_failure;
 452         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 453                 goto nla_put_failure;
 454
 455         if (p->default_index != NO_DEFAULT_INDEX &&
 456             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 457                 goto nla_put_failure;
 458
 459         if (p->set_tc_index &&
 460             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 461                 goto nla_put_failure;
 462
 463         return nla_nest_end(skb, opts);
 464
 465 nla_put_failure:
 466         nla_nest_cancel(skb, opts);
 467         return -EMSGSIZE;
 468 }
 469
 470 static const struct Qdisc_class_ops dsmark_class_ops = {
 471         .graft          =       dsmark_graft,
 472         .leaf           =       dsmark_leaf,
 473         .get            =       dsmark_get,
 474         .put            =       dsmark_put,
 475         .change         =       dsmark_change,
 476         .delete         =       dsmark_delete,
 477         .walk           =       dsmark_walk,
 478         .tcf_chain      =       dsmark_find_tcf,
 479         .bind_tcf       =       dsmark_bind_filter,
 480         .unbind_tcf     =       dsmark_put,
 481         .dump           =       dsmark_dump_class,
 482 };
 483
 484 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 485         .next           =       NULL,
 486         .cl_ops         =       &dsmark_class_ops,
 487         .id             =       "dsmark",
 488         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 489         .enqueue        =       dsmark_enqueue,
 490         .dequeue        =       dsmark_dequeue,
 491         .peek           =       dsmark_peek,
 492         .drop           =       dsmark_drop,
 493         .init           =       dsmark_init,
 494         .reset          =       dsmark_reset,
 495         .destroy        =       dsmark_destroy,
 496         .change         =       NULL,
 497         .dump           =       dsmark_dump,
 498         .owner          =       THIS_MODULE,
 499 };
 500
 501 static int __init dsmark_module_init(void)
 502 {
 503         return register_qdisc(&dsmark_qdisc_ops);
 504 }
 505
 506 static void __exit dsmark_module_exit(void)
 507 {
 508         unregister_qdisc(&dsmark_qdisc_ops);
 509 }
 510
 511 module_init(dsmark_module_init)
 512 module_exit(dsmark_module_exit)
 513
 514 MODULE_LICENSE("GPL");