net/sched/sch_dsmark.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* net/sched/sch_dsmark.c - Differentiated Services field marker */
   3
   4 /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
   5
   6
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/slab.h>
  10 #include <linux/types.h>
  11 #include <linux/string.h>
  12 #include <linux/errno.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/rtnetlink.h>
  15 #include <linux/bitops.h>
  16 #include <net/pkt_sched.h>
  17 #include <net/pkt_cls.h>
  18 #include <net/dsfield.h>
  19 #include <net/inet_ecn.h>
  20 #include <asm/byteorder.h>
  21
  22 /*
  23  * classid      class           marking
  24  * -------      -----           -------
  25  *   n/a          0             n/a
  26  *   x:0          1             use entry [0]
  27  *   ...         ...            ...
  28  *   x:y y>0     y+1            use entry [y]
  29  *   ...         ...            ...
  30  * x:indices-1  indices         use entry [indices-1]
  31  *   ...         ...            ...
  32  *   x:y         y+1            use entry [y & (indices-1)]
  33  *   ...         ...            ...
  34  * 0xffff       0x10000         use entry [indices-1]
  35  */
  36
  37
  38 #define NO_DEFAULT_INDEX        (1 << 16)
  39
  40 struct mask_value {
  41         u8                      mask;
  42         u8                      value;
  43 };
  44
  45 struct dsmark_qdisc_data {
  46         struct Qdisc            *q;
  47         struct tcf_proto __rcu  *filter_list;
  48         struct tcf_block        *block;
  49         struct mask_value       *mv;
  50         u16                     indices;
  51         u8                      set_tc_index;
  52         u32                     default_index;  /* index range is 0...0xffff */
  53 #define DSMARK_EMBEDDED_SZ      16
  54         struct mask_value       embedded[DSMARK_EMBEDDED_SZ];
  55 };
  56
  57 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
  58 {
  59         return index <= p->indices && index > 0;
  60 }
  61
  62 /* ------------------------- Class/flow operations ------------------------- */
  63
  64 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
  65                         struct Qdisc *new, struct Qdisc **old,
  66                         struct netlink_ext_ack *extack)
  67 {
  68         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  69
  70         pr_debug("%s(sch %p,[qdisc %p],new %p,old %p)\n",
  71                  __func__, sch, p, new, old);
  72
  73         if (new == NULL) {
  74                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
  75                                         sch->handle, NULL);
  76                 if (new == NULL)
  77                         new = &noop_qdisc;
  78         }
  79
  80         *old = qdisc_replace(sch, new, &p->q);
  81         return 0;
  82 }
  83
  84 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  85 {
  86         struct dsmark_qdisc_data *p = qdisc_priv(sch);
  87         return p->q;
  88 }
  89
  90 static unsigned long dsmark_find(struct Qdisc *sch, u32 classid)
  91 {
  92         return TC_H_MIN(classid) + 1;
  93 }
  94
  95 static unsigned long dsmark_bind_filter(struct Qdisc *sch,
  96                                         unsigned long parent, u32 classid)
  97 {
  98         pr_debug("%s(sch %p,[qdisc %p],classid %x)\n",
  99                  __func__, sch, qdisc_priv(sch), classid);
 100
 101         return dsmark_find(sch, classid);
 102 }
 103
 104 static void dsmark_unbind_filter(struct Qdisc *sch, unsigned long cl)
 105 {
 106 }
 107
 108 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
 109         [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
 110         [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
 111         [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
 112         [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
 113         [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
 114 };
 115
 116 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
 117                          struct nlattr **tca, unsigned long *arg,
 118                          struct netlink_ext_ack *extack)
 119 {
 120         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 121         struct nlattr *opt = tca[TCA_OPTIONS];
 122         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 123         int err = -EINVAL;
 124
 125         pr_debug("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",
 126                  __func__, sch, p, classid, parent, *arg);
 127
 128         if (!dsmark_valid_index(p, *arg)) {
 129                 err = -ENOENT;
 130                 goto errout;
 131         }
 132
 133         if (!opt)
 134                 goto errout;
 135
 136         err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
 137                                           dsmark_policy, NULL);
 138         if (err < 0)
 139                 goto errout;
 140
 141         if (tb[TCA_DSMARK_VALUE])
 142                 p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 143
 144         if (tb[TCA_DSMARK_MASK])
 145                 p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
 146
 147         err = 0;
 148
 149 errout:
 150         return err;
 151 }
 152
 153 static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
 154 {
 155         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 156
 157         if (!dsmark_valid_index(p, arg))
 158                 return -EINVAL;
 159
 160         p->mv[arg - 1].mask = 0xff;
 161         p->mv[arg - 1].value = 0;
 162
 163         return 0;
 164 }
 165
 166 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 167 {
 168         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 169         int i;
 170
 171         pr_debug("%s(sch %p,[qdisc %p],walker %p)\n",
 172                  __func__, sch, p, walker);
 173
 174         if (walker->stop)
 175                 return;
 176
 177         for (i = 0; i < p->indices; i++) {
 178                 if (p->mv[i].mask == 0xff && !p->mv[i].value)
 179                         goto ignore;
 180                 if (walker->count >= walker->skip) {
 181                         if (walker->fn(sch, i + 1, walker) < 0) {
 182                                 walker->stop = 1;
 183                                 break;
 184                         }
 185                 }
 186 ignore:
 187                 walker->count++;
 188         }
 189 }
 190
 191 static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
 192                                           struct netlink_ext_ack *extack)
 193 {
 194         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 195
 196         return p->block;
 197 }
 198
 199 /* --------------------------- Qdisc operations ---------------------------- */
 200
 201 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 202                           struct sk_buff **to_free)
 203 {
 204         unsigned int len = qdisc_pkt_len(skb);
 205         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 206         int err;
 207
 208         pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
 209
 210         if (p->set_tc_index) {
 211                 int wlen = skb_network_offset(skb);
 212
 213                 switch (tc_skb_protocol(skb)) {
 214                 case htons(ETH_P_IP):
 215                         wlen += sizeof(struct iphdr);
 216                         if (!pskb_may_pull(skb, wlen) ||
 217                             skb_try_make_writable(skb, wlen))
 218                                 goto drop;
 219
 220                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 221                                 & ~INET_ECN_MASK;
 222                         break;
 223
 224                 case htons(ETH_P_IPV6):
 225                         wlen += sizeof(struct ipv6hdr);
 226                         if (!pskb_may_pull(skb, wlen) ||
 227                             skb_try_make_writable(skb, wlen))
 228                                 goto drop;
 229
 230                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 231                                 & ~INET_ECN_MASK;
 232                         break;
 233                 default:
 234                         skb->tc_index = 0;
 235                         break;
 236                 }
 237         }
 238
 239         if (TC_H_MAJ(skb->priority) == sch->handle)
 240                 skb->tc_index = TC_H_MIN(skb->priority);
 241         else {
 242                 struct tcf_result res;
 243                 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 244                 int result = tcf_classify(skb, fl, &res, false);
 245
 246                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 247
 248                 switch (result) {
 249 #ifdef CONFIG_NET_CLS_ACT
 250                 case TC_ACT_QUEUED:
 251                 case TC_ACT_STOLEN:
 252                 case TC_ACT_TRAP:
 253                         __qdisc_drop(skb, to_free);
 254                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 255
 256                 case TC_ACT_SHOT:
 257                         goto drop;
 258 #endif
 259                 case TC_ACT_OK:
 260                         skb->tc_index = TC_H_MIN(res.classid);
 261                         break;
 262
 263                 default:
 264                         if (p->default_index != NO_DEFAULT_INDEX)
 265                                 skb->tc_index = p->default_index;
 266                         break;
 267                 }
 268         }
 269
 270         err = qdisc_enqueue(skb, p->q, to_free);
 271         if (err != NET_XMIT_SUCCESS) {
 272                 if (net_xmit_drop_count(err))
 273                         qdisc_qstats_drop(sch);
 274                 return err;
 275         }
 276
 277         sch->qstats.backlog += len;
 278         sch->q.qlen++;
 279
 280         return NET_XMIT_SUCCESS;
 281
 282 drop:
 283         qdisc_drop(skb, sch, to_free);
 284         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 285 }
 286
 287 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 288 {
 289         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 290         struct sk_buff *skb;
 291         u32 index;
 292
 293         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 294
 295         skb = qdisc_dequeue_peeked(p->q);
 296         if (skb == NULL)
 297                 return NULL;
 298
 299         qdisc_bstats_update(sch, skb);
 300         qdisc_qstats_backlog_dec(sch, skb);
 301         sch->q.qlen--;
 302
 303         index = skb->tc_index & (p->indices - 1);
 304         pr_debug("index %d->%d\n", skb->tc_index, index);
 305
 306         switch (tc_skb_protocol(skb)) {
 307         case htons(ETH_P_IP):
 308                 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
 309                                     p->mv[index].value);
 310                         break;
 311         case htons(ETH_P_IPV6):
 312                 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
 313                                     p->mv[index].value);
 314                         break;
 315         default:
 316                 /*
 317                  * Only complain if a change was actually attempted.
 318                  * This way, we can send non-IP traffic through dsmark
 319                  * and don't need yet another qdisc as a bypass.
 320                  */
 321                 if (p->mv[index].mask != 0xff || p->mv[index].value)
 322                         pr_warn("%s: unsupported protocol %d\n",
 323                                 __func__, ntohs(tc_skb_protocol(skb)));
 324                 break;
 325         }
 326
 327         return skb;
 328 }
 329
 330 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 331 {
 332         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 333
 334         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 335
 336         return p->q->ops->peek(p->q);
 337 }
 338
 339 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
 340                        struct netlink_ext_ack *extack)
 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         int i;
 348
 349         pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
 350
 351         if (!opt)
 352                 goto errout;
 353
 354         err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
 355         if (err)
 356                 return err;
 357
 358         err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
 359                                           dsmark_policy, NULL);
 360         if (err < 0)
 361                 goto errout;
 362
 363         err = -EINVAL;
 364         if (!tb[TCA_DSMARK_INDICES])
 365                 goto errout;
 366         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 367
 368         if (hweight32(indices) != 1)
 369                 goto errout;
 370
 371         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 372                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 373
 374         if (indices <= DSMARK_EMBEDDED_SZ)
 375                 p->mv = p->embedded;
 376         else
 377                 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
 378         if (!p->mv) {
 379                 err = -ENOMEM;
 380                 goto errout;
 381         }
 382         for (i = 0; i < indices; i++) {
 383                 p->mv[i].mask = 0xff;
 384                 p->mv[i].value = 0;
 385         }
 386         p->indices = indices;
 387         p->default_index = default_index;
 388         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 389
 390         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
 391                                  NULL);
 392         if (p->q == NULL)
 393                 p->q = &noop_qdisc;
 394         else
 395                 qdisc_hash_add(p->q, true);
 396
 397         pr_debug("%s: qdisc %p\n", __func__, 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("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 409         qdisc_reset(p->q);
 410         sch->qstats.backlog = 0;
 411         sch->q.qlen = 0;
 412 }
 413
 414 static void dsmark_destroy(struct Qdisc *sch)
 415 {
 416         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 417
 418         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 419
 420         tcf_block_put(p->block);
 421         qdisc_put(p->q);
 422         if (p->mv != p->embedded)
 423                 kfree(p->mv);
 424 }
 425
 426 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 427                              struct sk_buff *skb, struct tcmsg *tcm)
 428 {
 429         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 430         struct nlattr *opts = NULL;
 431
 432         pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
 433
 434         if (!dsmark_valid_index(p, cl))
 435                 return -EINVAL;
 436
 437         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 438         tcm->tcm_info = p->q->handle;
 439
 440         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 441         if (opts == NULL)
 442                 goto nla_put_failure;
 443         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
 444             nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
 445                 goto nla_put_failure;
 446
 447         return nla_nest_end(skb, opts);
 448
 449 nla_put_failure:
 450         nla_nest_cancel(skb, opts);
 451         return -EMSGSIZE;
 452 }
 453
 454 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 455 {
 456         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 457         struct nlattr *opts = NULL;
 458
 459         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 460         if (opts == NULL)
 461                 goto nla_put_failure;
 462         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 463                 goto nla_put_failure;
 464
 465         if (p->default_index != NO_DEFAULT_INDEX &&
 466             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 467                 goto nla_put_failure;
 468
 469         if (p->set_tc_index &&
 470             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 471                 goto nla_put_failure;
 472
 473         return nla_nest_end(skb, opts);
 474
 475 nla_put_failure:
 476         nla_nest_cancel(skb, opts);
 477         return -EMSGSIZE;
 478 }
 479
 480 static const struct Qdisc_class_ops dsmark_class_ops = {
 481         .graft          =       dsmark_graft,
 482         .leaf           =       dsmark_leaf,
 483         .find           =       dsmark_find,
 484         .change         =       dsmark_change,
 485         .delete         =       dsmark_delete,
 486         .walk           =       dsmark_walk,
 487         .tcf_block      =       dsmark_tcf_block,
 488         .bind_tcf       =       dsmark_bind_filter,
 489         .unbind_tcf     =       dsmark_unbind_filter,
 490         .dump           =       dsmark_dump_class,
 491 };
 492
 493 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 494         .next           =       NULL,
 495         .cl_ops         =       &dsmark_class_ops,
 496         .id             =       "dsmark",
 497         .priv_size      =       sizeof(struct dsmark_qdisc_data),
 498         .enqueue        =       dsmark_enqueue,
 499         .dequeue        =       dsmark_dequeue,
 500         .peek           =       dsmark_peek,
 501         .init           =       dsmark_init,
 502         .reset          =       dsmark_reset,
 503         .destroy        =       dsmark_destroy,
 504         .change         =       NULL,
 505         .dump           =       dsmark_dump,
 506         .owner          =       THIS_MODULE,
 507 };
 508
 509 static int __init dsmark_module_init(void)
 510 {
 511         return register_qdisc(&dsmark_qdisc_ops);
 512 }
 513
 514 static void __exit dsmark_module_exit(void)
 515 {
 516         unregister_qdisc(&dsmark_qdisc_ops);
 517 }
 518
 519 module_init(dsmark_module_init)
 520 module_exit(dsmark_module_exit)
 521
 522 MODULE_LICENSE("GPL");