net/openvswitch/meter.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2017 Nicira, Inc.
   4  */
   5
   6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/if.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/ip.h>
  11 #include <linux/kernel.h>
  12 #include <linux/openvswitch.h>
  13 #include <linux/netlink.h>
  14 #include <linux/rculist.h>
  15 #include <linux/swap.h>
  16
  17 #include <net/netlink.h>
  18 #include <net/genetlink.h>
  19
  20 #include "datapath.h"
  21 #include "meter.h"
  22
  23 static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
  24         [OVS_METER_ATTR_ID] = { .type = NLA_U32, },
  25         [OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG },
  26         [OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
  27         [OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED },
  28         [OVS_METER_ATTR_USED] = { .type = NLA_U64 },
  29         [OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG },
  30         [OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 },
  31         [OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 },
  32 };
  33
  34 static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = {
  35         [OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, },
  36         [OVS_BAND_ATTR_RATE] = { .type = NLA_U32, },
  37         [OVS_BAND_ATTR_BURST] = { .type = NLA_U32, },
  38         [OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
  39 };
  40
  41 static u32 meter_hash(struct dp_meter_instance *ti, u32 id)
  42 {
  43         return id % ti->n_meters;
  44 }
  45
  46 static void ovs_meter_free(struct dp_meter *meter)
  47 {
  48         if (!meter)
  49                 return;
  50
  51         kfree_rcu(meter, rcu);
  52 }
  53
  54 /* Call with ovs_mutex or RCU read lock. */
  55 static struct dp_meter *lookup_meter(const struct dp_meter_table *tbl,
  56                                      u32 meter_id)
  57 {
  58         struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
  59         u32 hash = meter_hash(ti, meter_id);
  60         struct dp_meter *meter;
  61
  62         meter = rcu_dereference_ovsl(ti->dp_meters[hash]);
  63         if (meter && likely(meter->id == meter_id))
  64                 return meter;
  65
  66         return NULL;
  67 }
  68
  69 static struct dp_meter_instance *dp_meter_instance_alloc(const u32 size)
  70 {
  71         struct dp_meter_instance *ti;
  72
  73         ti = kvzalloc(sizeof(*ti) +
  74                       sizeof(struct dp_meter *) * size,
  75                       GFP_KERNEL);
  76         if (!ti)
  77                 return NULL;
  78
  79         ti->n_meters = size;
  80
  81         return ti;
  82 }
  83
  84 static void dp_meter_instance_free(struct dp_meter_instance *ti)
  85 {
  86         kvfree(ti);
  87 }
  88
  89 static void dp_meter_instance_free_rcu(struct rcu_head *rcu)
  90 {
  91         struct dp_meter_instance *ti;
  92
  93         ti = container_of(rcu, struct dp_meter_instance, rcu);
  94         kvfree(ti);
  95 }
  96
  97 static int
  98 dp_meter_instance_realloc(struct dp_meter_table *tbl, u32 size)
  99 {
 100         struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
 101         int n_meters = min(size, ti->n_meters);
 102         struct dp_meter_instance *new_ti;
 103         int i;
 104
 105         new_ti = dp_meter_instance_alloc(size);
 106         if (!new_ti)
 107                 return -ENOMEM;
 108
 109         for (i = 0; i < n_meters; i++)
 110                 if (rcu_dereference_ovsl(ti->dp_meters[i]))
 111                         new_ti->dp_meters[i] = ti->dp_meters[i];
 112
 113         rcu_assign_pointer(tbl->ti, new_ti);
 114         call_rcu(&ti->rcu, dp_meter_instance_free_rcu);
 115
 116         return 0;
 117 }
 118
 119 static void dp_meter_instance_insert(struct dp_meter_instance *ti,
 120                                      struct dp_meter *meter)
 121 {
 122         u32 hash;
 123
 124         hash = meter_hash(ti, meter->id);
 125         rcu_assign_pointer(ti->dp_meters[hash], meter);
 126 }
 127
 128 static void dp_meter_instance_remove(struct dp_meter_instance *ti,
 129                                      struct dp_meter *meter)
 130 {
 131         u32 hash;
 132
 133         hash = meter_hash(ti, meter->id);
 134         RCU_INIT_POINTER(ti->dp_meters[hash], NULL);
 135 }
 136
 137 static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
 138 {
 139         struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
 140         u32 hash = meter_hash(ti, meter->id);
 141         int err;
 142
 143         /* In generally, slots selected should be empty, because
 144          * OvS uses id-pool to fetch a available id.
 145          */
 146         if (unlikely(rcu_dereference_ovsl(ti->dp_meters[hash])))
 147                 return -EBUSY;
 148
 149         dp_meter_instance_insert(ti, meter);
 150
 151         /* That function is thread-safe. */
 152         tbl->count++;
 153         if (tbl->count >= tbl->max_meters_allowed) {
 154                 err = -EFBIG;
 155                 goto attach_err;
 156         }
 157
 158         if (tbl->count >= ti->n_meters &&
 159             dp_meter_instance_realloc(tbl, ti->n_meters * 2)) {
 160                 err = -ENOMEM;
 161                 goto attach_err;
 162         }
 163
 164         return 0;
 165
 166 attach_err:
 167         dp_meter_instance_remove(ti, meter);
 168         tbl->count--;
 169         return err;
 170 }
 171
 172 static int detach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
 173 {
 174         struct dp_meter_instance *ti;
 175
 176         ASSERT_OVSL();
 177         if (!meter)
 178                 return 0;
 179
 180         ti = rcu_dereference_ovsl(tbl->ti);
 181         dp_meter_instance_remove(ti, meter);
 182
 183         tbl->count--;
 184
 185         /* Shrink the meter array if necessary. */
 186         if (ti->n_meters > DP_METER_ARRAY_SIZE_MIN &&
 187             tbl->count <= (ti->n_meters / 4)) {
 188                 int half_size = ti->n_meters / 2;
 189                 int i;
 190
 191                 /* Avoid hash collision, don't move slots to other place.
 192                  * Make sure there are no references of meters in array
 193                  * which will be released.
 194                  */
 195                 for (i = half_size; i < ti->n_meters; i++)
 196                         if (rcu_dereference_ovsl(ti->dp_meters[i]))
 197                                 goto out;
 198
 199                 if (dp_meter_instance_realloc(tbl, half_size))
 200                         goto shrink_err;
 201         }
 202
 203 out:
 204         return 0;
 205
 206 shrink_err:
 207         dp_meter_instance_insert(ti, meter);
 208         tbl->count++;
 209         return -ENOMEM;
 210 }
 211
 212 static struct sk_buff *
 213 ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd,
 214                           struct ovs_header **ovs_reply_header)
 215 {
 216         struct sk_buff *skb;
 217         struct ovs_header *ovs_header = info->userhdr;
 218
 219         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 220         if (!skb)
 221                 return ERR_PTR(-ENOMEM);
 222
 223         *ovs_reply_header = genlmsg_put(skb, info->snd_portid,
 224                                         info->snd_seq,
 225                                         &dp_meter_genl_family, 0, cmd);
 226         if (!*ovs_reply_header) {
 227                 nlmsg_free(skb);
 228                 return ERR_PTR(-EMSGSIZE);
 229         }
 230         (*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
 231
 232         return skb;
 233 }
 234
 235 static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
 236                                      struct dp_meter *meter)
 237 {
 238         struct nlattr *nla;
 239         struct dp_meter_band *band;
 240         u16 i;
 241
 242         if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
 243                 goto error;
 244
 245         if (nla_put(reply, OVS_METER_ATTR_STATS,
 246                     sizeof(struct ovs_flow_stats), &meter->stats))
 247                 goto error;
 248
 249         if (nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
 250                               OVS_METER_ATTR_PAD))
 251                 goto error;
 252
 253         nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
 254         if (!nla)
 255                 goto error;
 256
 257         band = meter->bands;
 258
 259         for (i = 0; i < meter->n_bands; ++i, ++band) {
 260                 struct nlattr *band_nla;
 261
 262                 band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC);
 263                 if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS,
 264                                          sizeof(struct ovs_flow_stats),
 265                                          &band->stats))
 266                         goto error;
 267                 nla_nest_end(reply, band_nla);
 268         }
 269         nla_nest_end(reply, nla);
 270
 271         return 0;
 272 error:
 273         return -EMSGSIZE;
 274 }
 275
 276 static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
 277 {
 278         struct ovs_header *ovs_header = info->userhdr;
 279         struct ovs_header *ovs_reply_header;
 280         struct nlattr *nla, *band_nla;
 281         struct sk_buff *reply;
 282         struct datapath *dp;
 283         int err = -EMSGSIZE;
 284
 285         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
 286                                           &ovs_reply_header);
 287         if (IS_ERR(reply))
 288                 return PTR_ERR(reply);
 289
 290         ovs_lock();
 291         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 292         if (!dp) {
 293                 err = -ENODEV;
 294                 goto exit_unlock;
 295         }
 296
 297         if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS,
 298                         dp->meter_tbl.max_meters_allowed))
 299                 goto exit_unlock;
 300
 301         ovs_unlock();
 302
 303         if (nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
 304                 goto nla_put_failure;
 305
 306         nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
 307         if (!nla)
 308                 goto nla_put_failure;
 309
 310         band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC);
 311         if (!band_nla)
 312                 goto nla_put_failure;
 313         /* Currently only DROP band type is supported. */
 314         if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP))
 315                 goto nla_put_failure;
 316         nla_nest_end(reply, band_nla);
 317         nla_nest_end(reply, nla);
 318
 319         genlmsg_end(reply, ovs_reply_header);
 320         return genlmsg_reply(reply, info);
 321
 322 exit_unlock:
 323         ovs_unlock();
 324 nla_put_failure:
 325         nlmsg_free(reply);
 326         return err;
 327 }
 328
 329 static struct dp_meter *dp_meter_create(struct nlattr **a)
 330 {
 331         struct nlattr *nla;
 332         int rem;
 333         u16 n_bands = 0;
 334         struct dp_meter *meter;
 335         struct dp_meter_band *band;
 336         int err;
 337
 338         /* Validate attributes, count the bands. */
 339         if (!a[OVS_METER_ATTR_BANDS])
 340                 return ERR_PTR(-EINVAL);
 341
 342         nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem)
 343                 if (++n_bands > DP_MAX_BANDS)
 344                         return ERR_PTR(-EINVAL);
 345
 346         /* Allocate and set up the meter before locking anything. */
 347         meter = kzalloc(struct_size(meter, bands, n_bands), GFP_KERNEL);
 348         if (!meter)
 349                 return ERR_PTR(-ENOMEM);
 350
 351         meter->id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 352         meter->used = div_u64(ktime_get_ns(), 1000 * 1000);
 353         meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0;
 354         meter->keep_stats = !a[OVS_METER_ATTR_CLEAR];
 355         spin_lock_init(&meter->lock);
 356         if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) {
 357                 meter->stats = *(struct ovs_flow_stats *)
 358                         nla_data(a[OVS_METER_ATTR_STATS]);
 359         }
 360         meter->n_bands = n_bands;
 361
 362         /* Set up meter bands. */
 363         band = meter->bands;
 364         nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) {
 365                 struct nlattr *attr[OVS_BAND_ATTR_MAX + 1];
 366                 u32 band_max_delta_t;
 367
 368                 err = nla_parse_deprecated((struct nlattr **)&attr,
 369                                            OVS_BAND_ATTR_MAX, nla_data(nla),
 370                                            nla_len(nla), band_policy, NULL);
 371                 if (err)
 372                         goto exit_free_meter;
 373
 374                 if (!attr[OVS_BAND_ATTR_TYPE] ||
 375                     !attr[OVS_BAND_ATTR_RATE] ||
 376                     !attr[OVS_BAND_ATTR_BURST]) {
 377                         err = -EINVAL;
 378                         goto exit_free_meter;
 379                 }
 380
 381                 band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
 382                 band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
 383                 if (band->rate == 0) {
 384                         err = -EINVAL;
 385                         goto exit_free_meter;
 386                 }
 387
 388                 band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
 389                 /* Figure out max delta_t that is enough to fill any bucket.
 390                  * Keep max_delta_t size to the bucket units:
 391                  * pkts => 1/1000 packets, kilobits => bits.
 392                  *
 393                  * Start with a full bucket.
 394                  */
 395                 band->bucket = (band->burst_size + band->rate) * 1000ULL;
 396                 band_max_delta_t = div_u64(band->bucket, band->rate);
 397                 if (band_max_delta_t > meter->max_delta_t)
 398                         meter->max_delta_t = band_max_delta_t;
 399                 band++;
 400         }
 401
 402         return meter;
 403
 404 exit_free_meter:
 405         kfree(meter);
 406         return ERR_PTR(err);
 407 }
 408
 409 static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
 410 {
 411         struct nlattr **a = info->attrs;
 412         struct dp_meter *meter, *old_meter;
 413         struct sk_buff *reply;
 414         struct ovs_header *ovs_reply_header;
 415         struct ovs_header *ovs_header = info->userhdr;
 416         struct dp_meter_table *meter_tbl;
 417         struct datapath *dp;
 418         int err;
 419         u32 meter_id;
 420         bool failed;
 421
 422         if (!a[OVS_METER_ATTR_ID])
 423                 return -EINVAL;
 424
 425         meter = dp_meter_create(a);
 426         if (IS_ERR_OR_NULL(meter))
 427                 return PTR_ERR(meter);
 428
 429         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
 430                                           &ovs_reply_header);
 431         if (IS_ERR(reply)) {
 432                 err = PTR_ERR(reply);
 433                 goto exit_free_meter;
 434         }
 435
 436         ovs_lock();
 437         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 438         if (!dp) {
 439                 err = -ENODEV;
 440                 goto exit_unlock;
 441         }
 442
 443         meter_tbl = &dp->meter_tbl;
 444         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 445
 446         old_meter = lookup_meter(meter_tbl, meter_id);
 447         err = detach_meter(meter_tbl, old_meter);
 448         if (err)
 449                 goto exit_unlock;
 450
 451         err = attach_meter(meter_tbl, meter);
 452         if (err)
 453                 goto exit_unlock;
 454
 455         ovs_unlock();
 456
 457         /* Build response with the meter_id and stats from
 458          * the old meter, if any.
 459          */
 460         failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
 461         WARN_ON(failed);
 462         if (old_meter) {
 463                 spin_lock_bh(&old_meter->lock);
 464                 if (old_meter->keep_stats) {
 465                         err = ovs_meter_cmd_reply_stats(reply, meter_id,
 466                                                         old_meter);
 467                         WARN_ON(err);
 468                 }
 469                 spin_unlock_bh(&old_meter->lock);
 470                 ovs_meter_free(old_meter);
 471         }
 472
 473         genlmsg_end(reply, ovs_reply_header);
 474         return genlmsg_reply(reply, info);
 475
 476 exit_unlock:
 477         ovs_unlock();
 478         nlmsg_free(reply);
 479 exit_free_meter:
 480         kfree(meter);
 481         return err;
 482 }
 483
 484 static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
 485 {
 486         struct ovs_header *ovs_header = info->userhdr;
 487         struct ovs_header *ovs_reply_header;
 488         struct nlattr **a = info->attrs;
 489         struct dp_meter *meter;
 490         struct sk_buff *reply;
 491         struct datapath *dp;
 492         u32 meter_id;
 493         int err;
 494
 495         if (!a[OVS_METER_ATTR_ID])
 496                 return -EINVAL;
 497
 498         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 499
 500         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
 501                                           &ovs_reply_header);
 502         if (IS_ERR(reply))
 503                 return PTR_ERR(reply);
 504
 505         ovs_lock();
 506
 507         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 508         if (!dp) {
 509                 err = -ENODEV;
 510                 goto exit_unlock;
 511         }
 512
 513         /* Locate meter, copy stats. */
 514         meter = lookup_meter(&dp->meter_tbl, meter_id);
 515         if (!meter) {
 516                 err = -ENOENT;
 517                 goto exit_unlock;
 518         }
 519
 520         spin_lock_bh(&meter->lock);
 521         err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
 522         spin_unlock_bh(&meter->lock);
 523         if (err)
 524                 goto exit_unlock;
 525
 526         ovs_unlock();
 527
 528         genlmsg_end(reply, ovs_reply_header);
 529         return genlmsg_reply(reply, info);
 530
 531 exit_unlock:
 532         ovs_unlock();
 533         nlmsg_free(reply);
 534         return err;
 535 }
 536
 537 static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
 538 {
 539         struct ovs_header *ovs_header = info->userhdr;
 540         struct ovs_header *ovs_reply_header;
 541         struct nlattr **a = info->attrs;
 542         struct dp_meter *old_meter;
 543         struct sk_buff *reply;
 544         struct datapath *dp;
 545         u32 meter_id;
 546         int err;
 547
 548         if (!a[OVS_METER_ATTR_ID])
 549                 return -EINVAL;
 550
 551         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
 552                                           &ovs_reply_header);
 553         if (IS_ERR(reply))
 554                 return PTR_ERR(reply);
 555
 556         ovs_lock();
 557
 558         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 559         if (!dp) {
 560                 err = -ENODEV;
 561                 goto exit_unlock;
 562         }
 563
 564         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 565         old_meter = lookup_meter(&dp->meter_tbl, meter_id);
 566         if (old_meter) {
 567                 spin_lock_bh(&old_meter->lock);
 568                 err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
 569                 WARN_ON(err);
 570                 spin_unlock_bh(&old_meter->lock);
 571
 572                 err = detach_meter(&dp->meter_tbl, old_meter);
 573                 if (err)
 574                         goto exit_unlock;
 575         }
 576
 577         ovs_unlock();
 578         ovs_meter_free(old_meter);
 579         genlmsg_end(reply, ovs_reply_header);
 580         return genlmsg_reply(reply, info);
 581
 582 exit_unlock:
 583         ovs_unlock();
 584         nlmsg_free(reply);
 585         return err;
 586 }
 587
 588 /* Meter action execution.
 589  *
 590  * Return true 'meter_id' drop band is triggered. The 'skb' should be
 591  * dropped by the caller'.
 592  */
 593 bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
 594                        struct sw_flow_key *key, u32 meter_id)
 595 {
 596         long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
 597         long long int long_delta_ms;
 598         struct dp_meter_band *band;
 599         struct dp_meter *meter;
 600         int i, band_exceeded_max = -1;
 601         u32 band_exceeded_rate = 0;
 602         u32 delta_ms;
 603         u32 cost;
 604
 605         meter = lookup_meter(&dp->meter_tbl, meter_id);
 606         /* Do not drop the packet when there is no meter. */
 607         if (!meter)
 608                 return false;
 609
 610         /* Lock the meter while using it. */
 611         spin_lock(&meter->lock);
 612
 613         long_delta_ms = (now_ms - meter->used); /* ms */
 614
 615         /* Make sure delta_ms will not be too large, so that bucket will not
 616          * wrap around below.
 617          */
 618         delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
 619                    ? meter->max_delta_t : (u32)long_delta_ms;
 620
 621         /* Update meter statistics.
 622          */
 623         meter->used = now_ms;
 624         meter->stats.n_packets += 1;
 625         meter->stats.n_bytes += skb->len;
 626
 627         /* Bucket rate is either in kilobits per second, or in packets per
 628          * second.  We maintain the bucket in the units of either bits or
 629          * 1/1000th of a packet, correspondingly.
 630          * Then, when rate is multiplied with milliseconds, we get the
 631          * bucket units:
 632          * msec * kbps = bits, and
 633          * msec * packets/sec = 1/1000 packets.
 634          *
 635          * 'cost' is the number of bucket units in this packet.
 636          */
 637         cost = (meter->kbps) ? skb->len * 8 : 1000;
 638
 639         /* Update all bands and find the one hit with the highest rate. */
 640         for (i = 0; i < meter->n_bands; ++i) {
 641                 long long int max_bucket_size;
 642
 643                 band = &meter->bands[i];
 644                 max_bucket_size = (band->burst_size + band->rate) * 1000LL;
 645
 646                 band->bucket += delta_ms * band->rate;
 647                 if (band->bucket > max_bucket_size)
 648                         band->bucket = max_bucket_size;
 649
 650                 if (band->bucket >= cost) {
 651                         band->bucket -= cost;
 652                 } else if (band->rate > band_exceeded_rate) {
 653                         band_exceeded_rate = band->rate;
 654                         band_exceeded_max = i;
 655                 }
 656         }
 657
 658         if (band_exceeded_max >= 0) {
 659                 /* Update band statistics. */
 660                 band = &meter->bands[band_exceeded_max];
 661                 band->stats.n_packets += 1;
 662                 band->stats.n_bytes += skb->len;
 663
 664                 /* Drop band triggered, let the caller drop the 'skb'.  */
 665                 if (band->type == OVS_METER_BAND_TYPE_DROP) {
 666                         spin_unlock(&meter->lock);
 667                         return true;
 668                 }
 669         }
 670
 671         spin_unlock(&meter->lock);
 672         return false;
 673 }
 674
 675 static struct genl_ops dp_meter_genl_ops[] = {
 676         { .cmd = OVS_METER_CMD_FEATURES,
 677                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 678                 .flags = 0,               /* OK for unprivileged users. */
 679                 .doit = ovs_meter_cmd_features
 680         },
 681         { .cmd = OVS_METER_CMD_SET,
 682                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 683                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 684                                            *  privilege.
 685                                            */
 686                 .doit = ovs_meter_cmd_set,
 687         },
 688         { .cmd = OVS_METER_CMD_GET,
 689                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 690                 .flags = 0,               /* OK for unprivileged users. */
 691                 .doit = ovs_meter_cmd_get,
 692         },
 693         { .cmd = OVS_METER_CMD_DEL,
 694                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 695                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 696                                            *  privilege.
 697                                            */
 698                 .doit = ovs_meter_cmd_del
 699         },
 700 };
 701
 702 static const struct genl_multicast_group ovs_meter_multicast_group = {
 703         .name = OVS_METER_MCGROUP,
 704 };
 705
 706 struct genl_family dp_meter_genl_family __ro_after_init = {
 707         .hdrsize = sizeof(struct ovs_header),
 708         .name = OVS_METER_FAMILY,
 709         .version = OVS_METER_VERSION,
 710         .maxattr = OVS_METER_ATTR_MAX,
 711         .policy = meter_policy,
 712         .netnsok = true,
 713         .parallel_ops = true,
 714         .ops = dp_meter_genl_ops,
 715         .n_ops = ARRAY_SIZE(dp_meter_genl_ops),
 716         .mcgrps = &ovs_meter_multicast_group,
 717         .n_mcgrps = 1,
 718         .module = THIS_MODULE,
 719 };
 720
 721 int ovs_meters_init(struct datapath *dp)
 722 {
 723         struct dp_meter_table *tbl = &dp->meter_tbl;
 724         struct dp_meter_instance *ti;
 725         unsigned long free_mem_bytes;
 726
 727         ti = dp_meter_instance_alloc(DP_METER_ARRAY_SIZE_MIN);
 728         if (!ti)
 729                 return -ENOMEM;
 730
 731         /* Allow meters in a datapath to use ~3.12% of physical memory. */
 732         free_mem_bytes = nr_free_buffer_pages() * (PAGE_SIZE >> 5);
 733         tbl->max_meters_allowed = min(free_mem_bytes / sizeof(struct dp_meter),
 734                                       DP_METER_NUM_MAX);
 735         if (!tbl->max_meters_allowed)
 736                 goto out_err;
 737
 738         rcu_assign_pointer(tbl->ti, ti);
 739         tbl->count = 0;
 740
 741         return 0;
 742
 743 out_err:
 744         dp_meter_instance_free(ti);
 745         return -ENOMEM;
 746 }
 747
 748 void ovs_meters_exit(struct datapath *dp)
 749 {
 750         struct dp_meter_table *tbl = &dp->meter_tbl;
 751         struct dp_meter_instance *ti = rcu_dereference_raw(tbl->ti);
 752         int i;
 753
 754         for (i = 0; i < ti->n_meters; i++)
 755                 ovs_meter_free(rcu_dereference_raw(ti->dp_meters[i]));
 756
 757         dp_meter_instance_free(ti);
 758 }