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                          struct netlink_ext_ack *extack)
 155 {
 156         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 157
 158         if (!dsmark_valid_index(p, arg))
 159                 return -EINVAL;
 160
 161         p->mv[arg - 1].mask = 0xff;
 162         p->mv[arg - 1].value = 0;
 163
 164         return 0;
 165 }
 166
 167 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 168 {
 169         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 170         int i;
 171
 172         pr_debug("%s(sch %p,[qdisc %p],walker %p)\n",
 173                  __func__, sch, p, walker);
 174
 175         if (walker->stop)
 176                 return;
 177
 178         for (i = 0; i < p->indices; i++) {
 179                 if (p->mv[i].mask == 0xff && !p->mv[i].value)
 180                         goto ignore;
 181                 if (walker->count >= walker->skip) {
 182                         if (walker->fn(sch, i + 1, walker) < 0) {
 183                                 walker->stop = 1;
 184                                 break;
 185                         }
 186                 }
 187 ignore:
 188                 walker->count++;
 189         }
 190 }
 191
 192 static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
 193                                           struct netlink_ext_ack *extack)
 194 {
 195         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 196
 197         return p->block;
 198 }
 199
 200 /* --------------------------- Qdisc operations ---------------------------- */
 201
 202 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 203                           struct sk_buff **to_free)
 204 {
 205         unsigned int len = qdisc_pkt_len(skb);
 206         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 207         int err;
 208
 209         pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
 210
 211         if (p->set_tc_index) {
 212                 int wlen = skb_network_offset(skb);
 213
 214                 switch (skb_protocol(skb, true)) {
 215                 case htons(ETH_P_IP):
 216                         wlen += sizeof(struct iphdr);
 217                         if (!pskb_may_pull(skb, wlen) ||
 218                             skb_try_make_writable(skb, wlen))
 219                                 goto drop;
 220
 221                         skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 222                                 & ~INET_ECN_MASK;
 223                         break;
 224
 225                 case htons(ETH_P_IPV6):
 226                         wlen += sizeof(struct ipv6hdr);
 227                         if (!pskb_may_pull(skb, wlen) ||
 228                             skb_try_make_writable(skb, wlen))
 229                                 goto drop;
 230
 231                         skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 232                                 & ~INET_ECN_MASK;
 233                         break;
 234                 default:
 235                         skb->tc_index = 0;
 236                         break;
 237                 }
 238         }
 239
 240         if (TC_H_MAJ(skb->priority) == sch->handle)
 241                 skb->tc_index = TC_H_MIN(skb->priority);
 242         else {
 243                 struct tcf_result res;
 244                 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
 245                 int result = tcf_classify(skb, NULL, fl, &res, false);
 246
 247                 pr_debug("result %d class 0x%04x\n", result, res.classid);
 248
 249                 switch (result) {
 250 #ifdef CONFIG_NET_CLS_ACT
 251                 case TC_ACT_QUEUED:
 252                 case TC_ACT_STOLEN:
 253                 case TC_ACT_TRAP:
 254                         __qdisc_drop(skb, to_free);
 255                         return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 256
 257                 case TC_ACT_SHOT:
 258                         goto drop;
 259 #endif
 260                 case TC_ACT_OK:
 261                         skb->tc_index = TC_H_MIN(res.classid);
 262                         break;
 263
 264                 default:
 265                         if (p->default_index != NO_DEFAULT_INDEX)
 266                                 skb->tc_index = p->default_index;
 267                         break;
 268                 }
 269         }
 270
 271         err = qdisc_enqueue(skb, p->q, to_free);
 272         if (err != NET_XMIT_SUCCESS) {
 273                 if (net_xmit_drop_count(err))
 274                         qdisc_qstats_drop(sch);
 275                 return err;
 276         }
 277
 278         sch->qstats.backlog += len;
 279         sch->q.qlen++;
 280
 281         return NET_XMIT_SUCCESS;
 282
 283 drop:
 284         qdisc_drop(skb, sch, to_free);
 285         return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 286 }
 287
 288 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 289 {
 290         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 291         struct sk_buff *skb;
 292         u32 index;
 293
 294         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 295
 296         skb = qdisc_dequeue_peeked(p->q);
 297         if (skb == NULL)
 298                 return NULL;
 299
 300         qdisc_bstats_update(sch, skb);
 301         qdisc_qstats_backlog_dec(sch, skb);
 302         sch->q.qlen--;
 303
 304         index = skb->tc_index & (p->indices - 1);
 305         pr_debug("index %d->%d\n", skb->tc_index, index);
 306
 307         switch (skb_protocol(skb, true)) {
 308         case htons(ETH_P_IP):
 309                 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
 310                                     p->mv[index].value);
 311                         break;
 312         case htons(ETH_P_IPV6):
 313                 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
 314                                     p->mv[index].value);
 315                         break;
 316         default:
 317                 /*
 318                  * Only complain if a change was actually attempted.
 319                  * This way, we can send non-IP traffic through dsmark
 320                  * and don't need yet another qdisc as a bypass.
 321                  */
 322                 if (p->mv[index].mask != 0xff || p->mv[index].value)
 323                         pr_warn("%s: unsupported protocol %d\n",
 324                                 __func__, ntohs(skb_protocol(skb, true)));
 325                 break;
 326         }
 327
 328         return skb;
 329 }
 330
 331 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 332 {
 333         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 334
 335         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 336
 337         return p->q->ops->peek(p->q);
 338 }
 339
 340 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
 341                        struct netlink_ext_ack *extack)
 342 {
 343         struct dsmark_qdisc_data *p = qdisc_priv(sch);
 344         struct nlattr *tb[TCA_DSMARK_MAX + 1];
 345         int err = -EINVAL;
 346         u32 default_index = NO_DEFAULT_INDEX;
 347         u16 indices;
 348         int i;
 349
 350         pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
 351
 352         if (!opt)
 353                 goto errout;
 354
 355         err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
 356         if (err)
 357                 return err;
 358
 359         err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
 360                                           dsmark_policy, NULL);
 361         if (err < 0)
 362                 goto errout;
 363
 364         err = -EINVAL;
 365         if (!tb[TCA_DSMARK_INDICES])
 366                 goto errout;
 367         indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 368
 369         if (hweight32(indices) != 1)
 370                 goto errout;
 371
 372         if (tb[TCA_DSMARK_DEFAULT_INDEX])
 373                 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 374
 375         if (indices <= DSMARK_EMBEDDED_SZ)
 376                 p->mv = p->embedded;
 377         else
 378                 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
 379         if (!p->mv) {
 380                 err = -ENOMEM;
 381                 goto errout;
 382         }
 383         for (i = 0; i < indices; i++) {
 384                 p->mv[i].mask = 0xff;
 385                 p->mv[i].value = 0;
 386         }
 387         p->indices = indices;
 388         p->default_index = default_index;
 389         p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 390
 391         p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
 392                                  NULL);
 393         if (p->q == NULL)
 394                 p->q = &noop_qdisc;
 395         else
 396                 qdisc_hash_add(p->q, true);
 397
 398         pr_debug("%s: qdisc %p\n", __func__, p->q);
 399
 400         err = 0;
 401 errout:
 402         return err;
 403 }
 404
 405 static void dsmark_reset(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         if (p->q)
 411                 qdisc_reset(p->q);
 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");