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/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(sch->dev, &pfifo_qdisc_ops,
  64                                         sch->handle);
  65                 if (new == NULL)
  66                         new = &noop_qdisc;
  67         }
  68
  69         sch_tree_lock(sch);
  70         *old = xchg(&p->q, new);
  71         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
  72         qdisc_reset(*old);
  73         sch_tree_unlock(sch);
  74
  75         return 0;
  76 }
  77
  78 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  79 {
  80         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  81         return p->q;
  82 }
  83
  84 static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
  85 {
  86         pr_debug("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
  87                 sch, qdisc_priv(sch), classid);
  88
  89         return TC_H_MIN(classid) + 1;
  90 }
  91
  92 static unsigned long dsmark_bind_filter(struct Qdisc *sch,
  93                                         unsigned long parent, u32 classid)
  94 {
  95         return dsmark_get(sch, classid);
  96 }
  97
  98 static void dsmark_put(struct Qdisc *sch, unsigned long cl)
  99 {
 100 }
 101
 102 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
 103         [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
 104         [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
 105         [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
 106         [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
 107         [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
 108 };
 109
 110 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
 111                          struct nlattr **tca, unsigned long *arg)
 112 {
 113         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 114         struct nlattr *opt = tca[TCA_OPTIONS];
 115         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 116         int err = -EINVAL;
 117         u8 mask = 0;
 118
 119         pr_debug("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
 120                 "arg 0x%lx\n", sch, p, classid, parent, *arg);
 121
 122         if (!dsmark_valid_index(p, *arg)) {
 123                 err = -ENOENT;
 124                 goto errout;
 125         }
 126
 127         if (!opt)
 128                 goto errout;
 129
 130         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 131         if (err < 0)
 132                 goto errout;
 133
 134         if (tb[TCA_DSMARK_MASK])
 135                 mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
 136
 137         if (tb[TCA_DSMARK_VALUE])
 138                 p->value[*arg-1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 139
 140         if (tb[TCA_DSMARK_MASK])
 141                 p->mask[*arg-1] = mask;
 142
 143         err = 0;
 144
 145 errout:
 146         return err;
 147 }
 148
 149 static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
 150 {
 151         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 152
 153         if (!dsmark_valid_index(p, arg))
 154                 return -EINVAL;
 155
 156         p->mask[arg-1] = 0xff;
 157         p->value[arg-1] = 0;
 158
 159         return 0;
 160 }
 161
 162 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 163 {
 164         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 165         int i;
 166
 167         pr_debug("dsmark_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
 168
 169         if (walker->stop)
 170                 return;
 171
 172         for (i = 0; i < p->indices; i++) {
 173                 if (p->mask[i] == 0xff && !p->value[i])
 174                         goto ignore;
 175                 if (walker->count >= walker->skip) {
 176                         if (walker->fn(sch, i+1, walker) < 0) {
 177                                 walker->stop = 1;
 178                                 break;
 179                         }
 180                 }
 181 ignore:
 182                 walker->count++;
 183         }
 184 }
 185
 186 static inline struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,
 187                                                  unsigned long cl)
 188 {
 189         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 190         return &p->filter_list;
 191 }
 192
 193 /* --------------------------- Qdisc operations ---------------------------- */
 194
 195 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 196 {
 197         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 198         int err;
 199
 200         pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
 201
 202         if (p->set_tc_index) {
 203                 switch (skb->protocol) {
 204                 case __constant_htons(ETH_P_IP):
 205                         if (skb_cow_head(skb, sizeof(struct iphdr)))
 206                                 goto drop;
 207
 208                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 209                                 & ~INET_ECN_MASK;
 210                         break;
 211
 212                 case __constant_htons(ETH_P_IPV6):
 213                         if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
 214                                 goto drop;
 215
 216                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 217                                 & ~INET_ECN_MASK;
 218                         break;
 219                 default:
 220                         skb->tc_index = 0;
 221                         break;
 222                 }
 223         }
 224
 225         if (TC_H_MAJ(skb->priority) == sch->handle)
 226                 skb->tc_index = TC_H_MIN(skb->priority);
 227         else {
 228                 struct tcf_result res;
 229                 int result = tc_classify(skb, p->filter_list, &res);
 230
 231                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 232
 233                 switch (result) {
 234 #ifdef CONFIG_NET_CLS_ACT
 235                 case TC_ACT_QUEUED:
 236                 case TC_ACT_STOLEN:
 237                         kfree_skb(skb);
 238                         return NET_XMIT_SUCCESS;
 239
 240                 case TC_ACT_SHOT:
 241                         goto drop;
 242 #endif
 243                 case TC_ACT_OK:
 244                         skb->tc_index = TC_H_MIN(res.classid);
 245                         break;
 246
 247                 default:
 248                         if (p->default_index != NO_DEFAULT_INDEX)
 249                                 skb->tc_index = p->default_index;
 250                         break;
 251                 }
 252         }
 253
 254         err = p->q->enqueue(skb, p->q);
 255         if (err != NET_XMIT_SUCCESS) {
 256                 sch->qstats.drops++;
 257                 return err;
 258         }
 259
 260         sch->bstats.bytes += skb->len;
 261         sch->bstats.packets++;
 262         sch->q.qlen++;
 263
 264         return NET_XMIT_SUCCESS;
 265
 266 drop:
 267         kfree_skb(skb);
 268         sch->qstats.drops++;
 269         return 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         sch->q.qlen--;
 285
 286         index = skb->tc_index & (p->indices - 1);
 287         pr_debug("index %d->%d\n", skb->tc_index, index);
 288
 289         switch (skb->protocol) {
 290         case __constant_htons(ETH_P_IP):
 291                 ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
 292                                     p->value[index]);
 293                         break;
 294         case __constant_htons(ETH_P_IPV6):
 295                 ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
 296                                     p->value[index]);
 297                         break;
 298         default:
 299                 /*
 300                  * Only complain if a change was actually attempted.
 301                  * This way, we can send non-IP traffic through dsmark
 302                  * and don't need yet another qdisc as a bypass.
 303                  */
 304                 if (p->mask[index] != 0xff || p->value[index])
 305                         printk(KERN_WARNING
 306                                "dsmark_dequeue: unsupported protocol %d\n",
 307                                ntohs(skb->protocol));
 308                 break;
 309         }
 310
 311         return skb;
 312 }
 313
 314 static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)
 315 {
 316         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 317         int err;
 318
 319         pr_debug("dsmark_requeue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
 320
 321         err = p->q->ops->requeue(skb, p->q);
 322         if (err != NET_XMIT_SUCCESS) {
 323                 sch->qstats.drops++;
 324                 return err;
 325         }
 326
 327         sch->q.qlen++;
 328         sch->qstats.requeues++;
 329
 330         return NET_XMIT_SUCCESS;
 331 }
 332
 333 static unsigned int dsmark_drop(struct Qdisc *sch)
 334 {
 335         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 336         unsigned int len;
 337
 338         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 339
 340         if (p->q->ops->drop == NULL)
 341                 return 0;
 342
 343         len = p->q->ops->drop(p->q);
 344         if (len)
 345                 sch->q.qlen--;
 346
 347         return len;
 348 }
 349
 350 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
 351 {
 352         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 353         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 354         int err = -EINVAL;
 355         u32 default_index = NO_DEFAULT_INDEX;
 356         u16 indices;
 357         u8 *mask;
 358
 359         pr_debug("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
 360
 361         if (!opt)
 362                 goto errout;
 363
 364         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 365         if (err < 0)
 366                 goto errout;
 367
 368         err = -EINVAL;
 369         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 370
 371         if (hweight32(indices) != 1)
 372                 goto errout;
 373
 374         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 375                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 376
 377         mask = kmalloc(indices * 2, GFP_KERNEL);
 378         if (mask == NULL) {
 379                 err = -ENOMEM;
 380                 goto errout;
 381         }
 382
 383         p->mask = mask;
 384         memset(p->mask, 0xff, indices);
 385
 386         p->value = p->mask + indices;
 387         memset(p->value, 0, indices);
 388
 389         p->indices = indices;
 390         p->default_index = default_index;
 391         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 392
 393         p->q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, sch->handle);
 394         if (p->q == NULL)
 395                 p->q = &noop_qdisc;
 396
 397         pr_debug("dsmark_init: qdisc %p\n", p->q);
 398
 399         err = 0;
 400 errout:
 401         return err;
 402 }
 403
 404 static void dsmark_reset(struct Qdisc *sch)
 405 {
 406         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 407
 408         pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 409         qdisc_reset(p->q);
 410         sch->q.qlen = 0;
 411 }
 412
 413 static void dsmark_destroy(struct Qdisc *sch)
 414 {
 415         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 416
 417         pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
 418
 419         tcf_destroy_chain(&p->filter_list);
 420         qdisc_destroy(p->q);
 421         kfree(p->mask);
 422 }
 423
 424 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 425                              struct sk_buff *skb, struct tcmsg *tcm)
 426 {
 427         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 428         struct nlattr *opts = NULL;
 429
 430         pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
 431
 432         if (!dsmark_valid_index(p, cl))
 433                 return -EINVAL;
 434
 435         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl-1);
 436         tcm->tcm_info = p->q->handle;
 437
 438         opts = nla_nest_start(skb, TCA_OPTIONS);
 439         if (opts == NULL)
 440                 goto nla_put_failure;
 441         NLA_PUT_U8(skb, TCA_DSMARK_MASK, p->mask[cl-1]);
 442         NLA_PUT_U8(skb, TCA_DSMARK_VALUE, p->value[cl-1]);
 443
 444         return nla_nest_end(skb, opts);
 445
 446 nla_put_failure:
 447         nla_nest_cancel(skb, opts);
 448         return -EMSGSIZE;
 449 }
 450
 451 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 452 {
 453         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 454         struct nlattr *opts = NULL;
 455
 456         opts = nla_nest_start(skb, TCA_OPTIONS);
 457         if (opts == NULL)
 458                 goto nla_put_failure;
 459         NLA_PUT_U16(skb, TCA_DSMARK_INDICES, p->indices);
 460
 461         if (p->default_index != NO_DEFAULT_INDEX)
 462                 NLA_PUT_U16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index);
 463
 464         if (p->set_tc_index)
 465                 NLA_PUT_FLAG(skb, TCA_DSMARK_SET_TC_INDEX);
 466
 467         return nla_nest_end(skb, opts);
 468
 469 nla_put_failure:
 470         nla_nest_cancel(skb, opts);
 471         return -EMSGSIZE;
 472 }
 473
 474 static const struct Qdisc_class_ops dsmark_class_ops = {
 475         .graft          =       dsmark_graft,
 476         .leaf           =       dsmark_leaf,
 477         .get            =       dsmark_get,
 478         .put            =       dsmark_put,
 479         .change         =       dsmark_change,
 480         .delete         =       dsmark_delete,
 481         .walk           =       dsmark_walk,
 482         .tcf_chain      =       dsmark_find_tcf,
 483         .bind_tcf       =       dsmark_bind_filter,
 484         .unbind_tcf     =       dsmark_put,
 485         .dump           =       dsmark_dump_class,
 486 };
 487
 488 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 489         .next           =       NULL,
 490         .cl_ops         =       &dsmark_class_ops,
 491         .id             =       "dsmark",
 492         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 493         .enqueue        =       dsmark_enqueue,
 494         .dequeue        =       dsmark_dequeue,
 495         .requeue        =       dsmark_requeue,
 496         .drop           =       dsmark_drop,
 497         .init           =       dsmark_init,
 498         .reset          =       dsmark_reset,
 499         .destroy        =       dsmark_destroy,
 500         .change         =       NULL,
 501         .dump           =       dsmark_dump,
 502         .owner          =       THIS_MODULE,
 503 };
 504
 505 static int __init dsmark_module_init(void)
 506 {
 507         return register_qdisc(&dsmark_qdisc_ops);
 508 }
 509
 510 static void __exit dsmark_module_exit(void)
 511 {
 512         unregister_qdisc(&dsmark_qdisc_ops);
 513 }
 514
 515 module_init(dsmark_module_init)
 516 module_exit(dsmark_module_exit)
 517
 518 MODULE_LICENSE("GPL");