net/openvswitch/meter.c

   1 /*
   2  * Copyright (c) 2017 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/if.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/ip.h>
  14 #include <linux/kernel.h>
  15 #include <linux/openvswitch.h>
  16 #include <linux/netlink.h>
  17 #include <linux/rculist.h>
  18
  19 #include <net/netlink.h>
  20 #include <net/genetlink.h>
  21
  22 #include "datapath.h"
  23 #include "meter.h"
  24
  25 #define METER_HASH_BUCKETS 1024
  26
  27 static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
  28         [OVS_METER_ATTR_ID] = { .type = NLA_U32, },
  29         [OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG },
  30         [OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
  31         [OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED },
  32         [OVS_METER_ATTR_USED] = { .type = NLA_U64 },
  33         [OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG },
  34         [OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 },
  35         [OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 },
  36 };
  37
  38 static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = {
  39         [OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, },
  40         [OVS_BAND_ATTR_RATE] = { .type = NLA_U32, },
  41         [OVS_BAND_ATTR_BURST] = { .type = NLA_U32, },
  42         [OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
  43 };
  44
  45 static void ovs_meter_free(struct dp_meter *meter)
  46 {
  47         if (!meter)
  48                 return;
  49
  50         kfree_rcu(meter, rcu);
  51 }
  52
  53 static struct hlist_head *meter_hash_bucket(const struct datapath *dp,
  54                                             u32 meter_id)
  55 {
  56         return &dp->meters[meter_id & (METER_HASH_BUCKETS - 1)];
  57 }
  58
  59 /* Call with ovs_mutex or RCU read lock. */
  60 static struct dp_meter *lookup_meter(const struct datapath *dp,
  61                                      u32 meter_id)
  62 {
  63         struct dp_meter *meter;
  64         struct hlist_head *head;
  65
  66         head = meter_hash_bucket(dp, meter_id);
  67         hlist_for_each_entry_rcu(meter, head, dp_hash_node) {
  68                 if (meter->id == meter_id)
  69                         return meter;
  70         }
  71         return NULL;
  72 }
  73
  74 static void attach_meter(struct datapath *dp, struct dp_meter *meter)
  75 {
  76         struct hlist_head *head = meter_hash_bucket(dp, meter->id);
  77
  78         hlist_add_head_rcu(&meter->dp_hash_node, head);
  79 }
  80
  81 static void detach_meter(struct dp_meter *meter)
  82 {
  83         ASSERT_OVSL();
  84         if (meter)
  85                 hlist_del_rcu(&meter->dp_hash_node);
  86 }
  87
  88 static struct sk_buff *
  89 ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd,
  90                           struct ovs_header **ovs_reply_header)
  91 {
  92         struct sk_buff *skb;
  93         struct ovs_header *ovs_header = info->userhdr;
  94
  95         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
  96         if (!skb)
  97                 return ERR_PTR(-ENOMEM);
  98
  99         *ovs_reply_header = genlmsg_put(skb, info->snd_portid,
 100                                         info->snd_seq,
 101                                         &dp_meter_genl_family, 0, cmd);
 102         if (!*ovs_reply_header) {
 103                 nlmsg_free(skb);
 104                 return ERR_PTR(-EMSGSIZE);
 105         }
 106         (*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
 107
 108         return skb;
 109 }
 110
 111 static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
 112                                      struct dp_meter *meter)
 113 {
 114         struct nlattr *nla;
 115         struct dp_meter_band *band;
 116         u16 i;
 117
 118         if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
 119                 goto error;
 120
 121         if (!meter)
 122                 return 0;
 123
 124         if (nla_put(reply, OVS_METER_ATTR_STATS,
 125                     sizeof(struct ovs_flow_stats), &meter->stats) ||
 126             nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
 127                               OVS_METER_ATTR_PAD))
 128                 goto error;
 129
 130         nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
 131         if (!nla)
 132                 goto error;
 133
 134         band = meter->bands;
 135
 136         for (i = 0; i < meter->n_bands; ++i, ++band) {
 137                 struct nlattr *band_nla;
 138
 139                 band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
 140                 if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS,
 141                                          sizeof(struct ovs_flow_stats),
 142                                          &band->stats))
 143                         goto error;
 144                 nla_nest_end(reply, band_nla);
 145         }
 146         nla_nest_end(reply, nla);
 147
 148         return 0;
 149 error:
 150         return -EMSGSIZE;
 151 }
 152
 153 static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
 154 {
 155         struct sk_buff *reply;
 156         struct ovs_header *ovs_reply_header;
 157         struct nlattr *nla, *band_nla;
 158         int err;
 159
 160         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
 161                                           &ovs_reply_header);
 162         if (IS_ERR(reply))
 163                 return PTR_ERR(reply);
 164
 165         if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS, U32_MAX) ||
 166             nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
 167                 goto nla_put_failure;
 168
 169         nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
 170         if (!nla)
 171                 goto nla_put_failure;
 172
 173         band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
 174         if (!band_nla)
 175                 goto nla_put_failure;
 176         /* Currently only DROP band type is supported. */
 177         if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP))
 178                 goto nla_put_failure;
 179         nla_nest_end(reply, band_nla);
 180         nla_nest_end(reply, nla);
 181
 182         genlmsg_end(reply, ovs_reply_header);
 183         return genlmsg_reply(reply, info);
 184
 185 nla_put_failure:
 186         nlmsg_free(reply);
 187         err = -EMSGSIZE;
 188         return err;
 189 }
 190
 191 static struct dp_meter *dp_meter_create(struct nlattr **a)
 192 {
 193         struct nlattr *nla;
 194         int rem;
 195         u16 n_bands = 0;
 196         struct dp_meter *meter;
 197         struct dp_meter_band *band;
 198         int err;
 199
 200         /* Validate attributes, count the bands. */
 201         if (!a[OVS_METER_ATTR_BANDS])
 202                 return ERR_PTR(-EINVAL);
 203
 204         nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem)
 205                 if (++n_bands > DP_MAX_BANDS)
 206                         return ERR_PTR(-EINVAL);
 207
 208         /* Allocate and set up the meter before locking anything. */
 209         meter = kzalloc(n_bands * sizeof(struct dp_meter_band) +
 210                         sizeof(*meter), GFP_KERNEL);
 211         if (!meter)
 212                 return ERR_PTR(-ENOMEM);
 213
 214         meter->used = div_u64(ktime_get_ns(), 1000 * 1000);
 215         meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0;
 216         meter->keep_stats = !a[OVS_METER_ATTR_CLEAR];
 217         spin_lock_init(&meter->lock);
 218         if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) {
 219                 meter->stats = *(struct ovs_flow_stats *)
 220                         nla_data(a[OVS_METER_ATTR_STATS]);
 221         }
 222         meter->n_bands = n_bands;
 223
 224         /* Set up meter bands. */
 225         band = meter->bands;
 226         nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) {
 227                 struct nlattr *attr[OVS_BAND_ATTR_MAX + 1];
 228                 u32 band_max_delta_t;
 229
 230                 err = nla_parse((struct nlattr **)&attr, OVS_BAND_ATTR_MAX,
 231                                 nla_data(nla), nla_len(nla), band_policy,
 232                                 NULL);
 233                 if (err)
 234                         goto exit_free_meter;
 235
 236                 if (!attr[OVS_BAND_ATTR_TYPE] ||
 237                     !attr[OVS_BAND_ATTR_RATE] ||
 238                     !attr[OVS_BAND_ATTR_BURST]) {
 239                         err = -EINVAL;
 240                         goto exit_free_meter;
 241                 }
 242
 243                 band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
 244                 band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
 245                 band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
 246                 /* Figure out max delta_t that is enough to fill any bucket.
 247                  * Keep max_delta_t size to the bucket units:
 248                  * pkts => 1/1000 packets, kilobits => bits.
 249                  */
 250                 band_max_delta_t = (band->burst_size + band->rate) * 1000;
 251                 /* Start with a full bucket. */
 252                 band->bucket = band_max_delta_t;
 253                 if (band_max_delta_t > meter->max_delta_t)
 254                         meter->max_delta_t = band_max_delta_t;
 255                 band++;
 256         }
 257
 258         return meter;
 259
 260 exit_free_meter:
 261         kfree(meter);
 262         return ERR_PTR(err);
 263 }
 264
 265 static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
 266 {
 267         struct nlattr **a = info->attrs;
 268         struct dp_meter *meter, *old_meter;
 269         struct sk_buff *reply;
 270         struct ovs_header *ovs_reply_header;
 271         struct ovs_header *ovs_header = info->userhdr;
 272         struct datapath *dp;
 273         int err;
 274         u32 meter_id;
 275         bool failed;
 276
 277         meter = dp_meter_create(a);
 278         if (IS_ERR_OR_NULL(meter))
 279                 return PTR_ERR(meter);
 280
 281         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
 282                                           &ovs_reply_header);
 283         if (IS_ERR(reply)) {
 284                 err = PTR_ERR(reply);
 285                 goto exit_free_meter;
 286         }
 287
 288         ovs_lock();
 289         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 290         if (!dp) {
 291                 err = -ENODEV;
 292                 goto exit_unlock;
 293         }
 294
 295         if (!a[OVS_METER_ATTR_ID]) {
 296                 err = -ENODEV;
 297                 goto exit_unlock;
 298         }
 299
 300         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 301
 302         /* Cannot fail after this. */
 303         old_meter = lookup_meter(dp, meter_id);
 304         detach_meter(old_meter);
 305         attach_meter(dp, meter);
 306         ovs_unlock();
 307
 308         /* Build response with the meter_id and stats from
 309          * the old meter, if any.
 310          */
 311         failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
 312         WARN_ON(failed);
 313         if (old_meter) {
 314                 spin_lock_bh(&old_meter->lock);
 315                 if (old_meter->keep_stats) {
 316                         err = ovs_meter_cmd_reply_stats(reply, meter_id,
 317                                                         old_meter);
 318                         WARN_ON(err);
 319                 }
 320                 spin_unlock_bh(&old_meter->lock);
 321                 ovs_meter_free(old_meter);
 322         }
 323
 324         genlmsg_end(reply, ovs_reply_header);
 325         return genlmsg_reply(reply, info);
 326
 327 exit_unlock:
 328         ovs_unlock();
 329         nlmsg_free(reply);
 330 exit_free_meter:
 331         kfree(meter);
 332         return err;
 333 }
 334
 335 static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
 336 {
 337         struct nlattr **a = info->attrs;
 338         u32 meter_id;
 339         struct ovs_header *ovs_header = info->userhdr;
 340         struct ovs_header *ovs_reply_header;
 341         struct datapath *dp;
 342         int err;
 343         struct sk_buff *reply;
 344         struct dp_meter *meter;
 345
 346         if (!a[OVS_METER_ATTR_ID])
 347                 return -EINVAL;
 348
 349         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 350
 351         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
 352                                           &ovs_reply_header);
 353         if (IS_ERR(reply))
 354                 return PTR_ERR(reply);
 355
 356         ovs_lock();
 357
 358         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 359         if (!dp) {
 360                 err = -ENODEV;
 361                 goto exit_unlock;
 362         }
 363
 364         /* Locate meter, copy stats. */
 365         meter = lookup_meter(dp, meter_id);
 366         if (!meter) {
 367                 err = -ENOENT;
 368                 goto exit_unlock;
 369         }
 370
 371         spin_lock_bh(&meter->lock);
 372         err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
 373         spin_unlock_bh(&meter->lock);
 374         if (err)
 375                 goto exit_unlock;
 376
 377         ovs_unlock();
 378
 379         genlmsg_end(reply, ovs_reply_header);
 380         return genlmsg_reply(reply, info);
 381
 382 exit_unlock:
 383         ovs_unlock();
 384         nlmsg_free(reply);
 385         return err;
 386 }
 387
 388 static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
 389 {
 390         struct nlattr **a = info->attrs;
 391         u32 meter_id;
 392         struct ovs_header *ovs_header = info->userhdr;
 393         struct ovs_header *ovs_reply_header;
 394         struct datapath *dp;
 395         int err;
 396         struct sk_buff *reply;
 397         struct dp_meter *old_meter;
 398
 399         if (!a[OVS_METER_ATTR_ID])
 400                 return -EINVAL;
 401         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 402
 403         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
 404                                           &ovs_reply_header);
 405         if (IS_ERR(reply))
 406                 return PTR_ERR(reply);
 407
 408         ovs_lock();
 409
 410         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 411         if (!dp) {
 412                 err = -ENODEV;
 413                 goto exit_unlock;
 414         }
 415
 416         old_meter = lookup_meter(dp, meter_id);
 417         if (old_meter) {
 418                 spin_lock_bh(&old_meter->lock);
 419                 err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
 420                 WARN_ON(err);
 421                 spin_unlock_bh(&old_meter->lock);
 422                 detach_meter(old_meter);
 423         }
 424         ovs_unlock();
 425         ovs_meter_free(old_meter);
 426         genlmsg_end(reply, ovs_reply_header);
 427         return genlmsg_reply(reply, info);
 428
 429 exit_unlock:
 430         ovs_unlock();
 431         nlmsg_free(reply);
 432         return err;
 433 }
 434
 435 /* Meter action execution.
 436  *
 437  * Return true 'meter_id' drop band is triggered. The 'skb' should be
 438  * dropped by the caller'.
 439  */
 440 bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
 441                        struct sw_flow_key *key, u32 meter_id)
 442 {
 443         struct dp_meter *meter;
 444         struct dp_meter_band *band;
 445         long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
 446         long long int long_delta_ms;
 447         u32 delta_ms;
 448         u32 cost;
 449         int i, band_exceeded_max = -1;
 450         u32 band_exceeded_rate = 0;
 451
 452         meter = lookup_meter(dp, meter_id);
 453         /* Do not drop the packet when there is no meter. */
 454         if (!meter)
 455                 return false;
 456
 457         /* Lock the meter while using it. */
 458         spin_lock(&meter->lock);
 459
 460         long_delta_ms = (now_ms - meter->used); /* ms */
 461
 462         /* Make sure delta_ms will not be too large, so that bucket will not
 463          * wrap around below.
 464          */
 465         delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
 466                    ? meter->max_delta_t : (u32)long_delta_ms;
 467
 468         /* Update meter statistics.
 469          */
 470         meter->used = now_ms;
 471         meter->stats.n_packets += 1;
 472         meter->stats.n_bytes += skb->len;
 473
 474         /* Bucket rate is either in kilobits per second, or in packets per
 475          * second.  We maintain the bucket in the units of either bits or
 476          * 1/1000th of a packet, correspondingly.
 477          * Then, when rate is multiplied with milliseconds, we get the
 478          * bucket units:
 479          * msec * kbps = bits, and
 480          * msec * packets/sec = 1/1000 packets.
 481          *
 482          * 'cost' is the number of bucket units in this packet.
 483          */
 484         cost = (meter->kbps) ? skb->len * 8 : 1000;
 485
 486         /* Update all bands and find the one hit with the highest rate. */
 487         for (i = 0; i < meter->n_bands; ++i) {
 488                 long long int max_bucket_size;
 489
 490                 band = &meter->bands[i];
 491                 max_bucket_size = (band->burst_size + band->rate) * 1000LL;
 492
 493                 band->bucket += delta_ms * band->rate;
 494                 if (band->bucket > max_bucket_size)
 495                         band->bucket = max_bucket_size;
 496
 497                 if (band->bucket >= cost) {
 498                         band->bucket -= cost;
 499                 } else if (band->rate > band_exceeded_rate) {
 500                         band_exceeded_rate = band->rate;
 501                         band_exceeded_max = i;
 502                 }
 503         }
 504
 505         if (band_exceeded_max >= 0) {
 506                 /* Update band statistics. */
 507                 band = &meter->bands[band_exceeded_max];
 508                 band->stats.n_packets += 1;
 509                 band->stats.n_bytes += skb->len;
 510
 511                 /* Drop band triggered, let the caller drop the 'skb'.  */
 512                 if (band->type == OVS_METER_BAND_TYPE_DROP) {
 513                         spin_unlock(&meter->lock);
 514                         return true;
 515                 }
 516         }
 517
 518         spin_unlock(&meter->lock);
 519         return false;
 520 }
 521
 522 static struct genl_ops dp_meter_genl_ops[] = {
 523         { .cmd = OVS_METER_CMD_FEATURES,
 524                 .flags = 0,               /* OK for unprivileged users. */
 525                 .policy = meter_policy,
 526                 .doit = ovs_meter_cmd_features
 527         },
 528         { .cmd = OVS_METER_CMD_SET,
 529                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 530                                            *  privilege.
 531                                            */
 532                 .policy = meter_policy,
 533                 .doit = ovs_meter_cmd_set,
 534         },
 535         { .cmd = OVS_METER_CMD_GET,
 536                 .flags = 0,               /* OK for unprivileged users. */
 537                 .policy = meter_policy,
 538                 .doit = ovs_meter_cmd_get,
 539         },
 540         { .cmd = OVS_METER_CMD_DEL,
 541                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 542                                            *  privilege.
 543                                            */
 544                 .policy = meter_policy,
 545                 .doit = ovs_meter_cmd_del
 546         },
 547 };
 548
 549 static const struct genl_multicast_group ovs_meter_multicast_group = {
 550         .name = OVS_METER_MCGROUP,
 551 };
 552
 553 struct genl_family dp_meter_genl_family __ro_after_init = {
 554         .hdrsize = sizeof(struct ovs_header),
 555         .name = OVS_METER_FAMILY,
 556         .version = OVS_METER_VERSION,
 557         .maxattr = OVS_METER_ATTR_MAX,
 558         .netnsok = true,
 559         .parallel_ops = true,
 560         .ops = dp_meter_genl_ops,
 561         .n_ops = ARRAY_SIZE(dp_meter_genl_ops),
 562         .mcgrps = &ovs_meter_multicast_group,
 563         .n_mcgrps = 1,
 564         .module = THIS_MODULE,
 565 };
 566
 567 int ovs_meters_init(struct datapath *dp)
 568 {
 569         int i;
 570
 571         dp->meters = kmalloc_array(METER_HASH_BUCKETS,
 572                                    sizeof(struct hlist_head), GFP_KERNEL);
 573
 574         if (!dp->meters)
 575                 return -ENOMEM;
 576
 577         for (i = 0; i < METER_HASH_BUCKETS; i++)
 578                 INIT_HLIST_HEAD(&dp->meters[i]);
 579
 580         return 0;
 581 }
 582
 583 void ovs_meters_exit(struct datapath *dp)
 584 {
 585         int i;
 586
 587         for (i = 0; i < METER_HASH_BUCKETS; i++) {
 588                 struct hlist_head *head = &dp->meters[i];
 589                 struct dp_meter *meter;
 590                 struct hlist_node *n;
 591
 592                 hlist_for_each_entry_safe(meter, n, head, dp_hash_node)
 593                         kfree(meter);
 594         }
 595
 596         kfree(dp->meters);
 597 }