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/pkt_cls.h>
  17 #include <net/dsfield.h>
  18 #include <net/inet_ecn.h>
  19 #include <asm/byteorder.h>
  20
  21 /*
  22  * classid      class           marking
  23  * -------      -----           -------
  24  *   n/a          0             n/a
  25  *   x:0          1             use entry [0]
  26  *   ...         ...            ...
  27  *   x:y y>0     y+1            use entry [y]
  28  *   ...         ...            ...
  29  * x:indices-1  indices         use entry [indices-1]
  30  *   ...         ...            ...
  31  *   x:y         y+1            use entry [y & (indices-1)]
  32  *   ...         ...            ...
  33  * 0xffff       0x10000         use entry [indices-1]
  34  */
  35
  36
  37 #define NO_DEFAULT_INDEX        (1 << 16)
  38
  39 struct mask_value {
  40         u8                      mask;
  41         u8                      value;
  42 };
  43
  44 struct dsmark_qdisc_data {
  45         struct Qdisc            *q;
  46         struct tcf_proto __rcu  *filter_list;
  47         struct tcf_block        *block;
  48         struct mask_value       *mv;
  49         u16                     indices;
  50         u8                      set_tc_index;
  51         u32                     default_index;  /* index range is 0...0xffff */
  52 #define DSMARK_EMBEDDED_SZ      16
  53         struct mask_value       embedded[DSMARK_EMBEDDED_SZ];
  54 };
  55
  56 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
  57 {
  58         return index <= p->indices && index > 0;
  59 }
  60
  61 /* ------------------------- Class/flow operations ------------------------- */
  62
  63 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
  64                         struct Qdisc *new, struct Qdisc **old,
  65                         struct netlink_ext_ack *extack)
  66 {
  67         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  68
  69         pr_debug("%s(sch %p,[qdisc %p],new %p,old %p)\n",
  70                  __func__, sch, p, new, old);
  71
  72         if (new == NULL) {
  73                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
  74                                         sch->handle, NULL);
  75                 if (new == NULL)
  76                         new = &noop_qdisc;
  77         }
  78
  79         *old = qdisc_replace(sch, new, &p->q);
  80         return 0;
  81 }
  82
  83 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  84 {
  85         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  86         return p->q;
  87 }
  88
  89 static unsigned long dsmark_find(struct Qdisc *sch, u32 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         pr_debug("%s(sch %p,[qdisc %p],classid %x)\n",
  98                  __func__, sch, qdisc_priv(sch), classid);
  99
 100         return dsmark_find(sch, classid);
 101 }
 102
 103 static void dsmark_unbind_filter(struct Qdisc *sch, unsigned long cl)
 104 {
 105 }
 106
 107 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
 108         [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
 109         [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
 110         [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
 111         [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
 112         [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
 113 };
 114
 115 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
 116                          struct nlattr **tca, unsigned long *arg,
 117                          struct netlink_ext_ack *extack)
 118 {
 119         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 120         struct nlattr *opt = tca[TCA_OPTIONS];
 121         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 122         int err = -EINVAL;
 123
 124         pr_debug("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",
 125                  __func__, sch, p, classid, parent, *arg);
 126
 127         if (!dsmark_valid_index(p, *arg)) {
 128                 err = -ENOENT;
 129                 goto errout;
 130         }
 131
 132         if (!opt)
 133                 goto errout;
 134
 135         err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
 136                                           dsmark_policy, NULL);
 137         if (err < 0)
 138                 goto errout;
 139
 140         if (tb[TCA_DSMARK_VALUE])
 141                 p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 142
 143         if (tb[TCA_DSMARK_MASK])
 144                 p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
 145
 146         err = 0;
 147
 148 errout:
 149         return err;
 150 }
 151
 152 static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
 153 {
 154         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 155
 156         if (!dsmark_valid_index(p, arg))
 157                 return -EINVAL;
 158
 159         p->mv[arg - 1].mask = 0xff;
 160         p->mv[arg - 1].value = 0;
 161
 162         return 0;
 163 }
 164
 165 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 166 {
 167         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 168         int i;
 169
 170         pr_debug("%s(sch %p,[qdisc %p],walker %p)\n",
 171                  __func__, sch, p, walker);
 172
 173         if (walker->stop)
 174                 return;
 175
 176         for (i = 0; i < p->indices; i++) {
 177                 if (p->mv[i].mask == 0xff && !p->mv[i].value)
 178                         goto ignore;
 179                 if (walker->count >= walker->skip) {
 180                         if (walker->fn(sch, i + 1, walker) < 0) {
 181                                 walker->stop = 1;
 182                                 break;
 183                         }
 184                 }
 185 ignore:
 186                 walker->count++;
 187         }
 188 }
 189
 190 static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
 191                                           struct netlink_ext_ack *extack)
 192 {
 193         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 194
 195         return p->block;
 196 }
 197
 198 /* --------------------------- Qdisc operations ---------------------------- */
 199
 200 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 201                           struct sk_buff **to_free)
 202 {
 203         unsigned int len = qdisc_pkt_len(skb);
 204         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 205         int err;
 206
 207         pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
 208
 209         if (p->set_tc_index) {
 210                 int wlen = skb_network_offset(skb);
 211
 212                 switch (tc_skb_protocol(skb)) {
 213                 case htons(ETH_P_IP):
 214                         wlen += sizeof(struct iphdr);
 215                         if (!pskb_may_pull(skb, wlen) ||
 216                             skb_try_make_writable(skb, wlen))
 217                                 goto drop;
 218
 219                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 220                                 & ~INET_ECN_MASK;
 221                         break;
 222
 223                 case htons(ETH_P_IPV6):
 224                         wlen += sizeof(struct ipv6hdr);
 225                         if (!pskb_may_pull(skb, wlen) ||
 226                             skb_try_make_writable(skb, wlen))
 227                                 goto drop;
 228
 229                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 230                                 & ~INET_ECN_MASK;
 231                         break;
 232                 default:
 233                         skb->tc_index = 0;
 234                         break;
 235                 }
 236         }
 237
 238         if (TC_H_MAJ(skb->priority) == sch->handle)
 239                 skb->tc_index = TC_H_MIN(skb->priority);
 240         else {
 241                 struct tcf_result res;
 242                 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 243                 int result = tcf_classify(skb, fl, &res, false);
 244
 245                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 246
 247                 switch (result) {
 248 #ifdef CONFIG_NET_CLS_ACT
 249                 case TC_ACT_QUEUED:
 250                 case TC_ACT_STOLEN:
 251                 case TC_ACT_TRAP:
 252                         __qdisc_drop(skb, to_free);
 253                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 254
 255                 case TC_ACT_SHOT:
 256                         goto drop;
 257 #endif
 258                 case TC_ACT_OK:
 259                         skb->tc_index = TC_H_MIN(res.classid);
 260                         break;
 261
 262                 default:
 263                         if (p->default_index != NO_DEFAULT_INDEX)
 264                                 skb->tc_index = p->default_index;
 265                         break;
 266                 }
 267         }
 268
 269         err = qdisc_enqueue(skb, p->q, to_free);
 270         if (err != NET_XMIT_SUCCESS) {
 271                 if (net_xmit_drop_count(err))
 272                         qdisc_qstats_drop(sch);
 273                 return err;
 274         }
 275
 276         sch->qstats.backlog += len;
 277         sch->q.qlen++;
 278
 279         return NET_XMIT_SUCCESS;
 280
 281 drop:
 282         qdisc_drop(skb, sch, to_free);
 283         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 284 }
 285
 286 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 287 {
 288         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 289         struct sk_buff *skb;
 290         u32 index;
 291
 292         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 293
 294         skb = qdisc_dequeue_peeked(p->q);
 295         if (skb == NULL)
 296                 return NULL;
 297
 298         qdisc_bstats_update(sch, skb);
 299         qdisc_qstats_backlog_dec(sch, skb);
 300         sch->q.qlen--;
 301
 302         index = skb->tc_index & (p->indices - 1);
 303         pr_debug("index %d->%d\n", skb->tc_index, index);
 304
 305         switch (tc_skb_protocol(skb)) {
 306         case htons(ETH_P_IP):
 307                 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
 308                                     p->mv[index].value);
 309                         break;
 310         case htons(ETH_P_IPV6):
 311                 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
 312                                     p->mv[index].value);
 313                         break;
 314         default:
 315                 /*
 316                  * Only complain if a change was actually attempted.
 317                  * This way, we can send non-IP traffic through dsmark
 318                  * and don't need yet another qdisc as a bypass.
 319                  */
 320                 if (p->mv[index].mask != 0xff || p->mv[index].value)
 321                         pr_warn("%s: unsupported protocol %d\n",
 322                                 __func__, ntohs(tc_skb_protocol(skb)));
 323                 break;
 324         }
 325
 326         return skb;
 327 }
 328
 329 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 330 {
 331         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 332
 333         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 334
 335         return p->q->ops->peek(p->q);
 336 }
 337
 338 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
 339                        struct netlink_ext_ack *extack)
 340 {
 341         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 342         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 343         int err = -EINVAL;
 344         u32 default_index = NO_DEFAULT_INDEX;
 345         u16 indices;
 346         int i;
 347
 348         pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
 349
 350         if (!opt)
 351                 goto errout;
 352
 353         err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
 354         if (err)
 355                 return err;
 356
 357         err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
 358                                           dsmark_policy, NULL);
 359         if (err < 0)
 360                 goto errout;
 361
 362         err = -EINVAL;
 363         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 364
 365         if (hweight32(indices) != 1)
 366                 goto errout;
 367
 368         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 369                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 370
 371         if (indices <= DSMARK_EMBEDDED_SZ)
 372                 p->mv = p->embedded;
 373         else
 374                 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
 375         if (!p->mv) {
 376                 err = -ENOMEM;
 377                 goto errout;
 378         }
 379         for (i = 0; i < indices; i++) {
 380                 p->mv[i].mask = 0xff;
 381                 p->mv[i].value = 0;
 382         }
 383         p->indices = indices;
 384         p->default_index = default_index;
 385         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 386
 387         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
 388                                  NULL);
 389         if (p->q == NULL)
 390                 p->q = &noop_qdisc;
 391         else
 392                 qdisc_hash_add(p->q, true);
 393
 394         pr_debug("%s: qdisc %p\n", __func__, p->q);
 395
 396         err = 0;
 397 errout:
 398         return err;
 399 }
 400
 401 static void dsmark_reset(struct Qdisc *sch)
 402 {
 403         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 404
 405         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 406         qdisc_reset(p->q);
 407         sch->qstats.backlog = 0;
 408         sch->q.qlen = 0;
 409 }
 410
 411 static void dsmark_destroy(struct Qdisc *sch)
 412 {
 413         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 414
 415         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 416
 417         tcf_block_put(p->block);
 418         qdisc_put(p->q);
 419         if (p->mv != p->embedded)
 420                 kfree(p->mv);
 421 }
 422
 423 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 424                              struct sk_buff *skb, struct tcmsg *tcm)
 425 {
 426         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 427         struct nlattr *opts = NULL;
 428
 429         pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
 430
 431         if (!dsmark_valid_index(p, cl))
 432                 return -EINVAL;
 433
 434         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 435         tcm->tcm_info = p->q->handle;
 436
 437         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 438         if (opts == NULL)
 439                 goto nla_put_failure;
 440         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
 441             nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
 442                 goto nla_put_failure;
 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_noflag(skb, TCA_OPTIONS);
 457         if (opts == NULL)
 458                 goto nla_put_failure;
 459         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 460                 goto nla_put_failure;
 461
 462         if (p->default_index != NO_DEFAULT_INDEX &&
 463             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 464                 goto nla_put_failure;
 465
 466         if (p->set_tc_index &&
 467             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 468                 goto nla_put_failure;
 469
 470         return nla_nest_end(skb, opts);
 471
 472 nla_put_failure:
 473         nla_nest_cancel(skb, opts);
 474         return -EMSGSIZE;
 475 }
 476
 477 static const struct Qdisc_class_ops dsmark_class_ops = {
 478         .graft          =       dsmark_graft,
 479         .leaf           =       dsmark_leaf,
 480         .find           =       dsmark_find,
 481         .change         =       dsmark_change,
 482         .delete         =       dsmark_delete,
 483         .walk           =       dsmark_walk,
 484         .tcf_block      =       dsmark_tcf_block,
 485         .bind_tcf       =       dsmark_bind_filter,
 486         .unbind_tcf     =       dsmark_unbind_filter,
 487         .dump           =       dsmark_dump_class,
 488 };
 489
 490 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 491         .next           =       NULL,
 492         .cl_ops         =       &dsmark_class_ops,
 493         .id             =       "dsmark",
 494         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 495         .enqueue        =       dsmark_enqueue,
 496         .dequeue        =       dsmark_dequeue,
 497         .peek           =       dsmark_peek,
 498         .init           =       dsmark_init,
 499         .reset          =       dsmark_reset,
 500         .destroy        =       dsmark_destroy,
 501         .change         =       NULL,
 502         .dump           =       dsmark_dump,
 503         .owner          =       THIS_MODULE,
 504 };
 505
 506 static int __init dsmark_module_init(void)
 507 {
 508         return register_qdisc(&dsmark_qdisc_ops);
 509 }
 510
 511 static void __exit dsmark_module_exit(void)
 512 {
 513         unregister_qdisc(&dsmark_qdisc_ops);
 514 }
 515
 516 module_init(dsmark_module_init)
 517 module_exit(dsmark_module_exit)
 518
 519 MODULE_LICENSE("GPL");