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(struct_size(meter, bands, n_bands), GFP_KERNEL);
 210         if (!meter)
 211                 return ERR_PTR(-ENOMEM);
 212
 213         meter->id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 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                 if (band->rate == 0) {
 246                         err = -EINVAL;
 247                         goto exit_free_meter;
 248                 }
 249
 250                 band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
 251                 /* Figure out max delta_t that is enough to fill any bucket.
 252                  * Keep max_delta_t size to the bucket units:
 253                  * pkts => 1/1000 packets, kilobits => bits.
 254                  *
 255                  * Start with a full bucket.
 256                  */
 257                 band->bucket = (band->burst_size + band->rate) * 1000;
 258                 band_max_delta_t = band->bucket / band->rate;
 259                 if (band_max_delta_t > meter->max_delta_t)
 260                         meter->max_delta_t = band_max_delta_t;
 261                 band++;
 262         }
 263
 264         return meter;
 265
 266 exit_free_meter:
 267         kfree(meter);
 268         return ERR_PTR(err);
 269 }
 270
 271 static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
 272 {
 273         struct nlattr **a = info->attrs;
 274         struct dp_meter *meter, *old_meter;
 275         struct sk_buff *reply;
 276         struct ovs_header *ovs_reply_header;
 277         struct ovs_header *ovs_header = info->userhdr;
 278         struct datapath *dp;
 279         int err;
 280         u32 meter_id;
 281         bool failed;
 282
 283         if (!a[OVS_METER_ATTR_ID]) {
 284                 return -ENODEV;
 285         }
 286
 287         meter = dp_meter_create(a);
 288         if (IS_ERR_OR_NULL(meter))
 289                 return PTR_ERR(meter);
 290
 291         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
 292                                           &ovs_reply_header);
 293         if (IS_ERR(reply)) {
 294                 err = PTR_ERR(reply);
 295                 goto exit_free_meter;
 296         }
 297
 298         ovs_lock();
 299         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 300         if (!dp) {
 301                 err = -ENODEV;
 302                 goto exit_unlock;
 303         }
 304
 305         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 306
 307         /* Cannot fail after this. */
 308         old_meter = lookup_meter(dp, meter_id);
 309         detach_meter(old_meter);
 310         attach_meter(dp, meter);
 311         ovs_unlock();
 312
 313         /* Build response with the meter_id and stats from
 314          * the old meter, if any.
 315          */
 316         failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
 317         WARN_ON(failed);
 318         if (old_meter) {
 319                 spin_lock_bh(&old_meter->lock);
 320                 if (old_meter->keep_stats) {
 321                         err = ovs_meter_cmd_reply_stats(reply, meter_id,
 322                                                         old_meter);
 323                         WARN_ON(err);
 324                 }
 325                 spin_unlock_bh(&old_meter->lock);
 326                 ovs_meter_free(old_meter);
 327         }
 328
 329         genlmsg_end(reply, ovs_reply_header);
 330         return genlmsg_reply(reply, info);
 331
 332 exit_unlock:
 333         ovs_unlock();
 334         nlmsg_free(reply);
 335 exit_free_meter:
 336         kfree(meter);
 337         return err;
 338 }
 339
 340 static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
 341 {
 342         struct nlattr **a = info->attrs;
 343         u32 meter_id;
 344         struct ovs_header *ovs_header = info->userhdr;
 345         struct ovs_header *ovs_reply_header;
 346         struct datapath *dp;
 347         int err;
 348         struct sk_buff *reply;
 349         struct dp_meter *meter;
 350
 351         if (!a[OVS_METER_ATTR_ID])
 352                 return -EINVAL;
 353
 354         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 355
 356         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
 357                                           &ovs_reply_header);
 358         if (IS_ERR(reply))
 359                 return PTR_ERR(reply);
 360
 361         ovs_lock();
 362
 363         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 364         if (!dp) {
 365                 err = -ENODEV;
 366                 goto exit_unlock;
 367         }
 368
 369         /* Locate meter, copy stats. */
 370         meter = lookup_meter(dp, meter_id);
 371         if (!meter) {
 372                 err = -ENOENT;
 373                 goto exit_unlock;
 374         }
 375
 376         spin_lock_bh(&meter->lock);
 377         err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
 378         spin_unlock_bh(&meter->lock);
 379         if (err)
 380                 goto exit_unlock;
 381
 382         ovs_unlock();
 383
 384         genlmsg_end(reply, ovs_reply_header);
 385         return genlmsg_reply(reply, info);
 386
 387 exit_unlock:
 388         ovs_unlock();
 389         nlmsg_free(reply);
 390         return err;
 391 }
 392
 393 static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
 394 {
 395         struct nlattr **a = info->attrs;
 396         u32 meter_id;
 397         struct ovs_header *ovs_header = info->userhdr;
 398         struct ovs_header *ovs_reply_header;
 399         struct datapath *dp;
 400         int err;
 401         struct sk_buff *reply;
 402         struct dp_meter *old_meter;
 403
 404         if (!a[OVS_METER_ATTR_ID])
 405                 return -EINVAL;
 406         meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 407
 408         reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
 409                                           &ovs_reply_header);
 410         if (IS_ERR(reply))
 411                 return PTR_ERR(reply);
 412
 413         ovs_lock();
 414
 415         dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
 416         if (!dp) {
 417                 err = -ENODEV;
 418                 goto exit_unlock;
 419         }
 420
 421         old_meter = lookup_meter(dp, meter_id);
 422         if (old_meter) {
 423                 spin_lock_bh(&old_meter->lock);
 424                 err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
 425                 WARN_ON(err);
 426                 spin_unlock_bh(&old_meter->lock);
 427                 detach_meter(old_meter);
 428         }
 429         ovs_unlock();
 430         ovs_meter_free(old_meter);
 431         genlmsg_end(reply, ovs_reply_header);
 432         return genlmsg_reply(reply, info);
 433
 434 exit_unlock:
 435         ovs_unlock();
 436         nlmsg_free(reply);
 437         return err;
 438 }
 439
 440 /* Meter action execution.
 441  *
 442  * Return true 'meter_id' drop band is triggered. The 'skb' should be
 443  * dropped by the caller'.
 444  */
 445 bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
 446                        struct sw_flow_key *key, u32 meter_id)
 447 {
 448         struct dp_meter *meter;
 449         struct dp_meter_band *band;
 450         long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
 451         long long int long_delta_ms;
 452         u32 delta_ms;
 453         u32 cost;
 454         int i, band_exceeded_max = -1;
 455         u32 band_exceeded_rate = 0;
 456
 457         meter = lookup_meter(dp, meter_id);
 458         /* Do not drop the packet when there is no meter. */
 459         if (!meter)
 460                 return false;
 461
 462         /* Lock the meter while using it. */
 463         spin_lock(&meter->lock);
 464
 465         long_delta_ms = (now_ms - meter->used); /* ms */
 466
 467         /* Make sure delta_ms will not be too large, so that bucket will not
 468          * wrap around below.
 469          */
 470         delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
 471                    ? meter->max_delta_t : (u32)long_delta_ms;
 472
 473         /* Update meter statistics.
 474          */
 475         meter->used = now_ms;
 476         meter->stats.n_packets += 1;
 477         meter->stats.n_bytes += skb->len;
 478
 479         /* Bucket rate is either in kilobits per second, or in packets per
 480          * second.  We maintain the bucket in the units of either bits or
 481          * 1/1000th of a packet, correspondingly.
 482          * Then, when rate is multiplied with milliseconds, we get the
 483          * bucket units:
 484          * msec * kbps = bits, and
 485          * msec * packets/sec = 1/1000 packets.
 486          *
 487          * 'cost' is the number of bucket units in this packet.
 488          */
 489         cost = (meter->kbps) ? skb->len * 8 : 1000;
 490
 491         /* Update all bands and find the one hit with the highest rate. */
 492         for (i = 0; i < meter->n_bands; ++i) {
 493                 long long int max_bucket_size;
 494
 495                 band = &meter->bands[i];
 496                 max_bucket_size = (band->burst_size + band->rate) * 1000LL;
 497
 498                 band->bucket += delta_ms * band->rate;
 499                 if (band->bucket > max_bucket_size)
 500                         band->bucket = max_bucket_size;
 501
 502                 if (band->bucket >= cost) {
 503                         band->bucket -= cost;
 504                 } else if (band->rate > band_exceeded_rate) {
 505                         band_exceeded_rate = band->rate;
 506                         band_exceeded_max = i;
 507                 }
 508         }
 509
 510         if (band_exceeded_max >= 0) {
 511                 /* Update band statistics. */
 512                 band = &meter->bands[band_exceeded_max];
 513                 band->stats.n_packets += 1;
 514                 band->stats.n_bytes += skb->len;
 515
 516                 /* Drop band triggered, let the caller drop the 'skb'.  */
 517                 if (band->type == OVS_METER_BAND_TYPE_DROP) {
 518                         spin_unlock(&meter->lock);
 519                         return true;
 520                 }
 521         }
 522
 523         spin_unlock(&meter->lock);
 524         return false;
 525 }
 526
 527 static struct genl_ops dp_meter_genl_ops[] = {
 528         { .cmd = OVS_METER_CMD_FEATURES,
 529                 .flags = 0,               /* OK for unprivileged users. */
 530                 .policy = meter_policy,
 531                 .doit = ovs_meter_cmd_features
 532         },
 533         { .cmd = OVS_METER_CMD_SET,
 534                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 535                                            *  privilege.
 536                                            */
 537                 .policy = meter_policy,
 538                 .doit = ovs_meter_cmd_set,
 539         },
 540         { .cmd = OVS_METER_CMD_GET,
 541                 .flags = 0,               /* OK for unprivileged users. */
 542                 .policy = meter_policy,
 543                 .doit = ovs_meter_cmd_get,
 544         },
 545         { .cmd = OVS_METER_CMD_DEL,
 546                 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
 547                                            *  privilege.
 548                                            */
 549                 .policy = meter_policy,
 550                 .doit = ovs_meter_cmd_del
 551         },
 552 };
 553
 554 static const struct genl_multicast_group ovs_meter_multicast_group = {
 555         .name = OVS_METER_MCGROUP,
 556 };
 557
 558 struct genl_family dp_meter_genl_family __ro_after_init = {
 559         .hdrsize = sizeof(struct ovs_header),
 560         .name = OVS_METER_FAMILY,
 561         .version = OVS_METER_VERSION,
 562         .maxattr = OVS_METER_ATTR_MAX,
 563         .netnsok = true,
 564         .parallel_ops = true,
 565         .ops = dp_meter_genl_ops,
 566         .n_ops = ARRAY_SIZE(dp_meter_genl_ops),
 567         .mcgrps = &ovs_meter_multicast_group,
 568         .n_mcgrps = 1,
 569         .module = THIS_MODULE,
 570 };
 571
 572 int ovs_meters_init(struct datapath *dp)
 573 {
 574         int i;
 575
 576         dp->meters = kmalloc_array(METER_HASH_BUCKETS,
 577                                    sizeof(struct hlist_head), GFP_KERNEL);
 578
 579         if (!dp->meters)
 580                 return -ENOMEM;
 581
 582         for (i = 0; i < METER_HASH_BUCKETS; i++)
 583                 INIT_HLIST_HEAD(&dp->meters[i]);
 584
 585         return 0;
 586 }
 587
 588 void ovs_meters_exit(struct datapath *dp)
 589 {
 590         int i;
 591
 592         for (i = 0; i < METER_HASH_BUCKETS; i++) {
 593                 struct hlist_head *head = &dp->meters[i];
 594                 struct dp_meter *meter;
 595                 struct hlist_node *n;
 596
 597                 hlist_for_each_entry_safe(meter, n, head, dp_hash_node)
 598                         kfree(meter);
 599         }
 600
 601         kfree(dp->meters);
 602 }