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(tb, TCA_DSMARK_MAX, opt, dsmark_policy, NULL);
 136         if (err < 0)
 137                 goto errout;
 138
 139         if (tb[TCA_DSMARK_VALUE])
 140                 p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 141
 142         if (tb[TCA_DSMARK_MASK])
 143                 p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_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->mv[arg - 1].mask = 0xff;
 159         p->mv[arg - 1].value = 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->mv[i].mask == 0xff && !p->mv[i].value)
 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 struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
 190                                           struct netlink_ext_ack *extack)
 191 {
 192         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 193
 194         return p->block;
 195 }
 196
 197 /* --------------------------- Qdisc operations ---------------------------- */
 198
 199 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 200                           struct sk_buff **to_free)
 201 {
 202         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 203         int err;
 204
 205         pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
 206
 207         if (p->set_tc_index) {
 208                 int wlen = skb_network_offset(skb);
 209
 210                 switch (tc_skb_protocol(skb)) {
 211                 case htons(ETH_P_IP):
 212                         wlen += sizeof(struct iphdr);
 213                         if (!pskb_may_pull(skb, wlen) ||
 214                             skb_try_make_writable(skb, wlen))
 215                                 goto drop;
 216
 217                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 218                                 & ~INET_ECN_MASK;
 219                         break;
 220
 221                 case htons(ETH_P_IPV6):
 222                         wlen += sizeof(struct ipv6hdr);
 223                         if (!pskb_may_pull(skb, wlen) ||
 224                             skb_try_make_writable(skb, wlen))
 225                                 goto drop;
 226
 227                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 228                                 & ~INET_ECN_MASK;
 229                         break;
 230                 default:
 231                         skb->tc_index = 0;
 232                         break;
 233                 }
 234         }
 235
 236         if (TC_H_MAJ(skb->priority) == sch->handle)
 237                 skb->tc_index = TC_H_MIN(skb->priority);
 238         else {
 239                 struct tcf_result res;
 240                 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 241                 int result = tcf_classify(skb, fl, &res, false);
 242
 243                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 244
 245                 switch (result) {
 246 #ifdef CONFIG_NET_CLS_ACT
 247                 case TC_ACT_QUEUED:
 248                 case TC_ACT_STOLEN:
 249                 case TC_ACT_TRAP:
 250                         __qdisc_drop(skb, to_free);
 251                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 252
 253                 case TC_ACT_SHOT:
 254                         goto drop;
 255 #endif
 256                 case TC_ACT_OK:
 257                         skb->tc_index = TC_H_MIN(res.classid);
 258                         break;
 259
 260                 default:
 261                         if (p->default_index != NO_DEFAULT_INDEX)
 262                                 skb->tc_index = p->default_index;
 263                         break;
 264                 }
 265         }
 266
 267         err = qdisc_enqueue(skb, p->q, to_free);
 268         if (err != NET_XMIT_SUCCESS) {
 269                 if (net_xmit_drop_count(err))
 270                         qdisc_qstats_drop(sch);
 271                 return err;
 272         }
 273
 274         qdisc_qstats_backlog_inc(sch, skb);
 275         sch->q.qlen++;
 276
 277         return NET_XMIT_SUCCESS;
 278
 279 drop:
 280         qdisc_drop(skb, sch, to_free);
 281         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 282 }
 283
 284 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 285 {
 286         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 287         struct sk_buff *skb;
 288         u32 index;
 289
 290         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 291
 292         skb = qdisc_dequeue_peeked(p->q);
 293         if (skb == NULL)
 294                 return NULL;
 295
 296         qdisc_bstats_update(sch, skb);
 297         qdisc_qstats_backlog_dec(sch, skb);
 298         sch->q.qlen--;
 299
 300         index = skb->tc_index & (p->indices - 1);
 301         pr_debug("index %d->%d\n", skb->tc_index, index);
 302
 303         switch (tc_skb_protocol(skb)) {
 304         case htons(ETH_P_IP):
 305                 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
 306                                     p->mv[index].value);
 307                         break;
 308         case htons(ETH_P_IPV6):
 309                 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
 310                                     p->mv[index].value);
 311                         break;
 312         default:
 313                 /*
 314                  * Only complain if a change was actually attempted.
 315                  * This way, we can send non-IP traffic through dsmark
 316                  * and don't need yet another qdisc as a bypass.
 317                  */
 318                 if (p->mv[index].mask != 0xff || p->mv[index].value)
 319                         pr_warn("%s: unsupported protocol %d\n",
 320                                 __func__, ntohs(tc_skb_protocol(skb)));
 321                 break;
 322         }
 323
 324         return skb;
 325 }
 326
 327 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 328 {
 329         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 330
 331         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 332
 333         return p->q->ops->peek(p->q);
 334 }
 335
 336 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
 337                        struct netlink_ext_ack *extack)
 338 {
 339         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 340         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 341         int err = -EINVAL;
 342         u32 default_index = NO_DEFAULT_INDEX;
 343         u16 indices;
 344         int i;
 345
 346         pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
 347
 348         if (!opt)
 349                 goto errout;
 350
 351         err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
 352         if (err)
 353                 return err;
 354
 355         err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy, NULL);
 356         if (err < 0)
 357                 goto errout;
 358
 359         err = -EINVAL;
 360         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 361
 362         if (hweight32(indices) != 1)
 363                 goto errout;
 364
 365         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 366                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 367
 368         if (indices <= DSMARK_EMBEDDED_SZ)
 369                 p->mv = p->embedded;
 370         else
 371                 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
 372         if (!p->mv) {
 373                 err = -ENOMEM;
 374                 goto errout;
 375         }
 376         for (i = 0; i < indices; i++) {
 377                 p->mv[i].mask = 0xff;
 378                 p->mv[i].value = 0;
 379         }
 380         p->indices = indices;
 381         p->default_index = default_index;
 382         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 383
 384         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
 385                                  NULL);
 386         if (p->q == NULL)
 387                 p->q = &noop_qdisc;
 388         else
 389                 qdisc_hash_add(p->q, true);
 390
 391         pr_debug("%s: qdisc %p\n", __func__, 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("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 403         qdisc_reset(p->q);
 404         sch->qstats.backlog = 0;
 405         sch->q.qlen = 0;
 406 }
 407
 408 static void dsmark_destroy(struct Qdisc *sch)
 409 {
 410         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 411
 412         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 413
 414         tcf_block_put(p->block);
 415         qdisc_put(p->q);
 416         if (p->mv != p->embedded)
 417                 kfree(p->mv);
 418 }
 419
 420 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 421                              struct sk_buff *skb, struct tcmsg *tcm)
 422 {
 423         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 424         struct nlattr *opts = NULL;
 425
 426         pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
 427
 428         if (!dsmark_valid_index(p, cl))
 429                 return -EINVAL;
 430
 431         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 432         tcm->tcm_info = p->q->handle;
 433
 434         opts = nla_nest_start(skb, TCA_OPTIONS);
 435         if (opts == NULL)
 436                 goto nla_put_failure;
 437         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
 438             nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
 439                 goto nla_put_failure;
 440
 441         return nla_nest_end(skb, opts);
 442
 443 nla_put_failure:
 444         nla_nest_cancel(skb, opts);
 445         return -EMSGSIZE;
 446 }
 447
 448 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 449 {
 450         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 451         struct nlattr *opts = NULL;
 452
 453         opts = nla_nest_start(skb, TCA_OPTIONS);
 454         if (opts == NULL)
 455                 goto nla_put_failure;
 456         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 457                 goto nla_put_failure;
 458
 459         if (p->default_index != NO_DEFAULT_INDEX &&
 460             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 461                 goto nla_put_failure;
 462
 463         if (p->set_tc_index &&
 464             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 465                 goto nla_put_failure;
 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         .find           =       dsmark_find,
 478         .change         =       dsmark_change,
 479         .delete         =       dsmark_delete,
 480         .walk           =       dsmark_walk,
 481         .tcf_block      =       dsmark_tcf_block,
 482         .bind_tcf       =       dsmark_bind_filter,
 483         .unbind_tcf     =       dsmark_unbind_filter,
 484         .dump           =       dsmark_dump_class,
 485 };
 486
 487 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 488         .next           =       NULL,
 489         .cl_ops         =       &dsmark_class_ops,
 490         .id             =       "dsmark",
 491         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 492         .enqueue        =       dsmark_enqueue,
 493         .dequeue        =       dsmark_dequeue,
 494         .peek           =       dsmark_peek,
 495         .init           =       dsmark_init,
 496         .reset          =       dsmark_reset,
 497         .destroy        =       dsmark_destroy,
 498         .change         =       NULL,
 499         .dump           =       dsmark_dump,
 500         .owner          =       THIS_MODULE,
 501 };
 502
 503 static int __init dsmark_module_init(void)
 504 {
 505         return register_qdisc(&dsmark_qdisc_ops);
 506 }
 507
 508 static void __exit dsmark_module_exit(void)
 509 {
 510         unregister_qdisc(&dsmark_qdisc_ops);
 511 }
 512
 513 module_init(dsmark_module_init)
 514 module_exit(dsmark_module_exit)
 515
 516 MODULE_LICENSE("GPL");