linux/net/sched/sch_dsmark.c
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   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/dsfield.h>
  17#include <net/inet_ecn.h>
  18#include <asm/byteorder.h>
  19
  20/*
  21 * classid      class           marking
  22 * -------      -----           -------
  23 *   n/a          0             n/a
  24 *   x:0          1             use entry [0]
  25 *   ...         ...            ...
  26 *   x:y y>0     y+1            use entry [y]
  27 *   ...         ...            ...
  28 * x:indices-1  indices         use entry [indices-1]
  29 *   ...         ...            ...
  30 *   x:y         y+1            use entry [y & (indices-1)]
  31 *   ...         ...            ...
  32 * 0xffff       0x10000         use entry [indices-1]
  33 */
  34
  35
  36#define NO_DEFAULT_INDEX        (1 << 16)
  37
  38struct dsmark_qdisc_data {
  39        struct Qdisc            *q;
  40        struct tcf_proto        *filter_list;
  41        u8                      *mask;  /* "owns" the array */
  42        u8                      *value;
  43        u16                     indices;
  44        u32                     default_index;  /* index range is 0...0xffff */
  45        int                     set_tc_index;
  46};
  47
  48static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
  49{
  50        return (index <= p->indices && index > 0);
  51}
  52
  53/* ------------------------- Class/flow operations ------------------------- */
  54
  55static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
  56                        struct Qdisc *new, struct Qdisc **old)
  57{
  58        struct dsmark_qdisc_data *p = qdisc_priv(sch);
  59
  60        pr_debug("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
  61                sch, p, new, old);
  62
  63        if (new == NULL) {
  64                new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
  65                                        sch->handle);
  66                if (new == NULL)
  67                        new = &noop_qdisc;
  68        }
  69
  70        sch_tree_lock(sch);
  71        *old = p->q;
  72        p->q = new;
  73        qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
  74        qdisc_reset(*old);
  75        sch_tree_unlock(sch);
  76
  77        return 0;
  78}
  79
  80static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
  81{
  82        struct dsmark_qdisc_data *p = qdisc_priv(sch);
  83        return p->q;
  84}
  85
  86static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
  87{
  88        pr_debug("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
  89                sch, qdisc_priv(sch), classid);
  90
  91        return TC_H_MIN(classid) + 1;
  92}
  93
  94static unsigned long dsmark_bind_filter(struct Qdisc *sch,
  95                                        unsigned long parent, u32 classid)
  96{
  97        return dsmark_get(sch, classid);
  98}
  99
 100static void dsmark_put(struct Qdisc *sch, unsigned long cl)
 101{
 102}
 103
 104static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
 105        [TCA_DSMARK_INDICES]            = { .type = NLA_U16 },
 106        [TCA_DSMARK_DEFAULT_INDEX]      = { .type = NLA_U16 },
 107        [TCA_DSMARK_SET_TC_INDEX]       = { .type = NLA_FLAG },
 108        [TCA_DSMARK_MASK]               = { .type = NLA_U8 },
 109        [TCA_DSMARK_VALUE]              = { .type = NLA_U8 },
 110};
 111
 112static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
 113                         struct nlattr **tca, unsigned long *arg)
 114{
 115        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 116        struct nlattr *opt = tca[TCA_OPTIONS];
 117        struct nlattr *tb[TCA_DSMARK_MAX + 1];
 118        int err = -EINVAL;
 119        u8 mask = 0;
 120
 121        pr_debug("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
 122                "arg 0x%lx\n", sch, p, classid, parent, *arg);
 123
 124        if (!dsmark_valid_index(p, *arg)) {
 125                err = -ENOENT;
 126                goto errout;
 127        }
 128
 129        if (!opt)
 130                goto errout;
 131
 132        err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 133        if (err < 0)
 134                goto errout;
 135
 136        if (tb[TCA_DSMARK_MASK])
 137                mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
 138
 139        if (tb[TCA_DSMARK_VALUE])
 140                p->value[*arg - 1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);
 141
 142        if (tb[TCA_DSMARK_MASK])
 143                p->mask[*arg - 1] = mask;
 144
 145        err = 0;
 146
 147errout:
 148        return err;
 149}
 150
 151static 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->mask[arg - 1] = 0xff;
 159        p->value[arg - 1] = 0;
 160
 161        return 0;
 162}
 163
 164static 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("dsmark_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
 170
 171        if (walker->stop)
 172                return;
 173
 174        for (i = 0; i < p->indices; i++) {
 175                if (p->mask[i] == 0xff && !p->value[i])
 176                        goto ignore;
 177                if (walker->count >= walker->skip) {
 178                        if (walker->fn(sch, i + 1, walker) < 0) {
 179                                walker->stop = 1;
 180                                break;
 181                        }
 182                }
 183ignore:
 184                walker->count++;
 185        }
 186}
 187
 188static inline struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,
 189                                                 unsigned long cl)
 190{
 191        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 192        return &p->filter_list;
 193}
 194
 195/* --------------------------- Qdisc operations ---------------------------- */
 196
 197static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 198{
 199        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 200        int err;
 201
 202        pr_debug("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
 203
 204        if (p->set_tc_index) {
 205                switch (skb->protocol) {
 206                case htons(ETH_P_IP):
 207                        if (skb_cow_head(skb, sizeof(struct iphdr)))
 208                                goto drop;
 209
 210                        skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
 211                                & ~INET_ECN_MASK;
 212                        break;
 213
 214                case htons(ETH_P_IPV6):
 215                        if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
 216                                goto drop;
 217
 218                        skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
 219                                & ~INET_ECN_MASK;
 220                        break;
 221                default:
 222                        skb->tc_index = 0;
 223                        break;
 224                }
 225        }
 226
 227        if (TC_H_MAJ(skb->priority) == sch->handle)
 228                skb->tc_index = TC_H_MIN(skb->priority);
 229        else {
 230                struct tcf_result res;
 231                int result = tc_classify(skb, p->filter_list, &res);
 232
 233                pr_debug("result %d class 0x%04x\n", result, res.classid);
 234
 235                switch (result) {
 236#ifdef CONFIG_NET_CLS_ACT
 237                case TC_ACT_QUEUED:
 238                case TC_ACT_STOLEN:
 239                        kfree_skb(skb);
 240                        return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 241
 242                case TC_ACT_SHOT:
 243                        goto drop;
 244#endif
 245                case TC_ACT_OK:
 246                        skb->tc_index = TC_H_MIN(res.classid);
 247                        break;
 248
 249                default:
 250                        if (p->default_index != NO_DEFAULT_INDEX)
 251                                skb->tc_index = p->default_index;
 252                        break;
 253                }
 254        }
 255
 256        err = qdisc_enqueue(skb, p->q);
 257        if (err != NET_XMIT_SUCCESS) {
 258                if (net_xmit_drop_count(err))
 259                        sch->qstats.drops++;
 260                return err;
 261        }
 262
 263        sch->q.qlen++;
 264
 265        return NET_XMIT_SUCCESS;
 266
 267drop:
 268        qdisc_drop(skb, sch);
 269        return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 270}
 271
 272static 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        qdisc_bstats_update(sch, skb);
 285        sch->q.qlen--;
 286
 287        index = skb->tc_index & (p->indices - 1);
 288        pr_debug("index %d->%d\n", skb->tc_index, index);
 289
 290        switch (skb->protocol) {
 291        case htons(ETH_P_IP):
 292                ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
 293                                    p->value[index]);
 294                        break;
 295        case htons(ETH_P_IPV6):
 296                ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
 297                                    p->value[index]);
 298                        break;
 299        default:
 300                /*
 301                 * Only complain if a change was actually attempted.
 302                 * This way, we can send non-IP traffic through dsmark
 303                 * and don't need yet another qdisc as a bypass.
 304                 */
 305                if (p->mask[index] != 0xff || p->value[index])
 306                        pr_warning("dsmark_dequeue: unsupported protocol %d\n",
 307                                   ntohs(skb->protocol));
 308                break;
 309        }
 310
 311        return skb;
 312}
 313
 314static struct sk_buff *dsmark_peek(struct Qdisc *sch)
 315{
 316        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 317
 318        pr_debug("dsmark_peek(sch %p,[qdisc %p])\n", sch, p);
 319
 320        return p->q->ops->peek(p->q);
 321}
 322
 323static unsigned int dsmark_drop(struct Qdisc *sch)
 324{
 325        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 326        unsigned int len;
 327
 328        pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 329
 330        if (p->q->ops->drop == NULL)
 331                return 0;
 332
 333        len = p->q->ops->drop(p->q);
 334        if (len)
 335                sch->q.qlen--;
 336
 337        return len;
 338}
 339
 340static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
 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        u8 *mask;
 348
 349        pr_debug("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
 350
 351        if (!opt)
 352                goto errout;
 353
 354        err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
 355        if (err < 0)
 356                goto errout;
 357
 358        err = -EINVAL;
 359        indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
 360
 361        if (hweight32(indices) != 1)
 362                goto errout;
 363
 364        if (tb[TCA_DSMARK_DEFAULT_INDEX])
 365                default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
 366
 367        mask = kmalloc(indices * 2, GFP_KERNEL);
 368        if (mask == NULL) {
 369                err = -ENOMEM;
 370                goto errout;
 371        }
 372
 373        p->mask = mask;
 374        memset(p->mask, 0xff, indices);
 375
 376        p->value = p->mask + indices;
 377        memset(p->value, 0, indices);
 378
 379        p->indices = indices;
 380        p->default_index = default_index;
 381        p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
 382
 383        p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle);
 384        if (p->q == NULL)
 385                p->q = &noop_qdisc;
 386
 387        pr_debug("dsmark_init: qdisc %p\n", p->q);
 388
 389        err = 0;
 390errout:
 391        return err;
 392}
 393
 394static void dsmark_reset(struct Qdisc *sch)
 395{
 396        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 397
 398        pr_debug("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
 399        qdisc_reset(p->q);
 400        sch->q.qlen = 0;
 401}
 402
 403static void dsmark_destroy(struct Qdisc *sch)
 404{
 405        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 406
 407        pr_debug("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
 408
 409        tcf_destroy_chain(&p->filter_list);
 410        qdisc_destroy(p->q);
 411        kfree(p->mask);
 412}
 413
 414static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
 415                             struct sk_buff *skb, struct tcmsg *tcm)
 416{
 417        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 418        struct nlattr *opts = NULL;
 419
 420        pr_debug("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
 421
 422        if (!dsmark_valid_index(p, cl))
 423                return -EINVAL;
 424
 425        tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
 426        tcm->tcm_info = p->q->handle;
 427
 428        opts = nla_nest_start(skb, TCA_OPTIONS);
 429        if (opts == NULL)
 430                goto nla_put_failure;
 431        if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mask[cl - 1]) ||
 432            nla_put_u8(skb, TCA_DSMARK_VALUE, p->value[cl - 1]))
 433                goto nla_put_failure;
 434
 435        return nla_nest_end(skb, opts);
 436
 437nla_put_failure:
 438        nla_nest_cancel(skb, opts);
 439        return -EMSGSIZE;
 440}
 441
 442static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
 443{
 444        struct dsmark_qdisc_data *p = qdisc_priv(sch);
 445        struct nlattr *opts = NULL;
 446
 447        opts = nla_nest_start(skb, TCA_OPTIONS);
 448        if (opts == NULL)
 449                goto nla_put_failure;
 450        if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
 451                goto nla_put_failure;
 452
 453        if (p->default_index != NO_DEFAULT_INDEX &&
 454            nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
 455                goto nla_put_failure;
 456
 457        if (p->set_tc_index &&
 458            nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
 459                goto nla_put_failure;
 460
 461        return nla_nest_end(skb, opts);
 462
 463nla_put_failure:
 464        nla_nest_cancel(skb, opts);
 465        return -EMSGSIZE;
 466}
 467
 468static const struct Qdisc_class_ops dsmark_class_ops = {
 469        .graft          =       dsmark_graft,
 470        .leaf           =       dsmark_leaf,
 471        .get            =       dsmark_get,
 472        .put            =       dsmark_put,
 473        .change         =       dsmark_change,
 474        .delete         =       dsmark_delete,
 475        .walk           =       dsmark_walk,
 476        .tcf_chain      =       dsmark_find_tcf,
 477        .bind_tcf       =       dsmark_bind_filter,
 478        .unbind_tcf     =       dsmark_put,
 479        .dump           =       dsmark_dump_class,
 480};
 481
 482static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
 483        .next           =       NULL,
 484        .cl_ops         =       &dsmark_class_ops,
 485        .id             =       "dsmark",
 486        .priv_size      =       sizeof(struct dsmark_qdisc_data),
 487        .enqueue        =       dsmark_enqueue,
 488        .dequeue        =       dsmark_dequeue,
 489        .peek           =       dsmark_peek,
 490        .drop           =       dsmark_drop,
 491        .init           =       dsmark_init,
 492        .reset          =       dsmark_reset,
 493        .destroy        =       dsmark_destroy,
 494        .change         =       NULL,
 495        .dump           =       dsmark_dump,
 496        .owner          =       THIS_MODULE,
 497};
 498
 499static int __init dsmark_module_init(void)
 500{
 501        return register_qdisc(&dsmark_qdisc_ops);
 502}
 503
 504static void __exit dsmark_module_exit(void)
 505{
 506        unregister_qdisc(&dsmark_qdisc_ops);
 507}
 508
 509module_init(dsmark_module_init)
 510module_exit(dsmark_module_exit)
 511
 512MODULE_LICENSE("GPL");
 513
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