vnet/vnet/dpo/load_balance.c

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <vnet/ip/lookup.h>
  17 #include <vnet/dpo/load_balance.h>
  18 #include <vnet/dpo/load_balance_map.h>
  19 #include <vnet/dpo/drop_dpo.h>
  20 #include <vppinfra/math.h>              /* for fabs */
  21 #include <vnet/adj/adj.h>
  22 #include <vnet/adj/adj_internal.h>
  23 #include <vnet/fib/fib_urpf_list.h>
  24
  25 /*
  26  * distribution error tolerance for load-balancing
  27  */
  28 const f64 multipath_next_hop_error_tolerance = 0.1;
  29
  30 #undef LB_DEBUG
  31
  32 #ifdef LB_DEBUG
  33 #define LB_DBG(_lb, _fmt, _args...)                                     \
  34 {                                                                       \
  35     u8* _tmp =NULL;                                                     \
  36     clib_warning("lb:[%s]:" _fmt,                                       \
  37                  load_balance_format(load_balance_get_index((_lb)),     \
  38                                      0, _tmp),                          \
  39                  ##_args);                                              \
  40     vec_free(_tmp);                                                     \
  41 }
  42 #else
  43 #define LB_DBG(_p, _fmt, _args...)
  44 #endif
  45
  46
  47 /**
  48  * Pool of all DPOs. It's not static so the DP can have fast access
  49  */
  50 load_balance_t *load_balance_pool;
  51
  52 /**
  53  * The one instance of load-balance main
  54  */
  55 load_balance_main_t load_balance_main;
  56
  57 f64
  58 load_balance_get_multipath_tolerance (void)
  59 {
  60     return (multipath_next_hop_error_tolerance);
  61 }
  62
  63 static inline index_t
  64 load_balance_get_index (const load_balance_t *lb)
  65 {
  66     return (lb - load_balance_pool);
  67 }
  68
  69 static inline dpo_id_t*
  70 load_balance_get_buckets (load_balance_t *lb)
  71 {
  72     if (LB_HAS_INLINE_BUCKETS(lb))
  73     {
  74         return (lb->lb_buckets_inline);
  75     }
  76     else
  77     {
  78         return (lb->lb_buckets);
  79     }
  80 }
  81
  82 static load_balance_t *
  83 load_balance_alloc_i (void)
  84 {
  85     load_balance_t *lb;
  86
  87     pool_get_aligned(load_balance_pool, lb, CLIB_CACHE_LINE_BYTES);
  88     memset(lb, 0, sizeof(*lb));
  89
  90     lb->lb_map = INDEX_INVALID;
  91     lb->lb_urpf = INDEX_INVALID;
  92     vlib_validate_combined_counter(&(load_balance_main.lbm_to_counters),
  93                                    load_balance_get_index(lb));
  94     vlib_validate_combined_counter(&(load_balance_main.lbm_via_counters),
  95                                    load_balance_get_index(lb));
  96     vlib_zero_combined_counter(&(load_balance_main.lbm_to_counters),
  97                                load_balance_get_index(lb));
  98     vlib_zero_combined_counter(&(load_balance_main.lbm_via_counters),
  99                                load_balance_get_index(lb));
 100
 101     return (lb);
 102 }
 103
 104 static u8*
 105 load_balance_format (index_t lbi,
 106                      load_balance_format_flags_t flags,
 107                      u32 indent,
 108                      u8 *s)
 109 {
 110     vlib_counter_t to, via;
 111     load_balance_t *lb;
 112     dpo_id_t *buckets;
 113     u32 i;
 114
 115     lb = load_balance_get(lbi);
 116     vlib_get_combined_counter(&(load_balance_main.lbm_to_counters), lbi, &to);
 117     vlib_get_combined_counter(&(load_balance_main.lbm_via_counters), lbi, &via);
 118     buckets = load_balance_get_buckets(lb);
 119
 120     s = format(s, "%U: ", format_dpo_type, DPO_LOAD_BALANCE);
 121     s = format(s, "[index:%d buckets:%d ", lbi, lb->lb_n_buckets);
 122     s = format(s, "uRPF:%d ", lb->lb_urpf);
 123     s = format(s, "to:[%Ld:%Ld]", to.packets, to.bytes);
 124     if (0 != via.packets)
 125     {
 126         s = format(s, " via:[%Ld:%Ld]",
 127                    via.packets, via.bytes);
 128     }
 129     s = format(s, "]");
 130
 131     if (INDEX_INVALID != lb->lb_map)
 132     {
 133         s = format(s, "\n%U%U",
 134                    format_white_space, indent+4,
 135                    format_load_balance_map, lb->lb_map, indent+4);
 136     }
 137     for (i = 0; i < lb->lb_n_buckets; i++)
 138     {
 139         s = format(s, "\n%U[%d] %U",
 140                    format_white_space, indent+2,
 141                    i,
 142                    format_dpo_id,
 143                    &buckets[i], indent+6);
 144     }
 145     return (s);
 146 }
 147
 148 u8*
 149 format_load_balance (u8 * s, va_list * args)
 150 {
 151     index_t lbi = va_arg(*args, index_t);
 152     load_balance_format_flags_t flags = va_arg(*args, load_balance_format_flags_t);
 153
 154     return (load_balance_format(lbi, flags, 0, s));
 155 }
 156 static u8*
 157 format_load_balance_dpo (u8 * s, va_list * args)
 158 {
 159     index_t lbi = va_arg(*args, index_t);
 160     u32 indent = va_arg(*args, u32);
 161
 162     return (load_balance_format(lbi, LOAD_BALANCE_FORMAT_DETAIL, indent, s));
 163 }
 164
 165
 166 static load_balance_t *
 167 load_balance_create_i (u32 num_buckets,
 168                        dpo_proto_t lb_proto,
 169                        flow_hash_config_t fhc)
 170 {
 171     load_balance_t *lb;
 172
 173     lb = load_balance_alloc_i();
 174     lb->lb_hash_config = fhc;
 175     lb->lb_n_buckets = num_buckets;
 176     lb->lb_n_buckets_minus_1 = num_buckets-1;
 177     lb->lb_proto = lb_proto;
 178
 179     if (!LB_HAS_INLINE_BUCKETS(lb))
 180     {
 181         vec_validate_aligned(lb->lb_buckets,
 182                              lb->lb_n_buckets - 1,
 183                              CLIB_CACHE_LINE_BYTES);
 184     }
 185
 186     LB_DBG(lb, "create");
 187
 188     return (lb);
 189 }
 190
 191 index_t
 192 load_balance_create (u32 n_buckets,
 193                      dpo_proto_t lb_proto,
 194                      flow_hash_config_t fhc)
 195 {
 196     return (load_balance_get_index(load_balance_create_i(n_buckets, lb_proto, fhc)));
 197 }
 198
 199 static inline void
 200 load_balance_set_bucket_i (load_balance_t *lb,
 201                            u32 bucket,
 202                            dpo_id_t *buckets,
 203                            const dpo_id_t *next)
 204 {
 205     dpo_stack(DPO_LOAD_BALANCE, lb->lb_proto, &buckets[bucket], next);
 206 }
 207
 208 void
 209 load_balance_set_bucket (index_t lbi,
 210                          u32 bucket,
 211                          const dpo_id_t *next)
 212 {
 213     load_balance_t *lb;
 214     dpo_id_t *buckets;
 215
 216     lb = load_balance_get(lbi);
 217     buckets = load_balance_get_buckets(lb);
 218
 219     ASSERT(bucket < lb->lb_n_buckets);
 220
 221     load_balance_set_bucket_i(lb, bucket, buckets, next);
 222 }
 223
 224 int
 225 load_balance_is_drop (const dpo_id_t *dpo)
 226 {
 227     load_balance_t *lb;
 228
 229     if (DPO_LOAD_BALANCE != dpo->dpoi_type)
 230         return (0);
 231
 232     lb = load_balance_get(dpo->dpoi_index);
 233
 234     if (1 == lb->lb_n_buckets)
 235     {
 236         return (dpo_is_drop(load_balance_get_bucket_i(lb, 0)));
 237     }
 238     return (0);
 239 }
 240
 241 void
 242 load_balance_set_urpf (index_t lbi,
 243                        index_t urpf)
 244 {
 245     load_balance_t *lb;
 246     index_t old;
 247
 248     lb = load_balance_get(lbi);
 249
 250     /*
 251      * packets in flight we see this change. but it's atomic, so :P
 252      */
 253     old = lb->lb_urpf;
 254     lb->lb_urpf = urpf;
 255
 256     fib_urpf_list_unlock(old);
 257     fib_urpf_list_lock(urpf);
 258 }
 259
 260 index_t
 261 load_balance_get_urpf (index_t lbi)
 262 {
 263     load_balance_t *lb;
 264
 265     lb = load_balance_get(lbi);
 266
 267     return (lb->lb_urpf);
 268 }
 269
 270 const dpo_id_t *
 271 load_balance_get_bucket (index_t lbi,
 272                          u32 bucket)
 273 {
 274     load_balance_t *lb;
 275
 276     lb = load_balance_get(lbi);
 277
 278     return (load_balance_get_bucket_i(lb, bucket));
 279 }
 280
 281 static int
 282 next_hop_sort_by_weight (load_balance_path_t * n1,
 283                          load_balance_path_t * n2)
 284 {
 285     return ((int) n1->path_weight - (int) n2->path_weight);
 286 }
 287
 288 /* Given next hop vector is over-written with normalized one with sorted weights and
 289    with weights corresponding to the number of adjacencies for each next hop.
 290    Returns number of adjacencies in block. */
 291 u32
 292 ip_multipath_normalize_next_hops (load_balance_path_t * raw_next_hops,
 293                                   load_balance_path_t ** normalized_next_hops,
 294                                   u32 *sum_weight_in,
 295                                   f64 multipath_next_hop_error_tolerance)
 296 {
 297     load_balance_path_t * nhs;
 298     uword n_nhs, n_adj, n_adj_left, i, sum_weight;
 299     f64 norm, error;
 300
 301     n_nhs = vec_len (raw_next_hops);
 302     ASSERT (n_nhs > 0);
 303     if (n_nhs == 0)
 304         return 0;
 305
 306     /* Allocate enough space for 2 copies; we'll use second copy to save original weights. */
 307     nhs = *normalized_next_hops;
 308     vec_validate (nhs, 2*n_nhs - 1);
 309
 310     /* Fast path: 1 next hop in block. */
 311     n_adj = n_nhs;
 312     if (n_nhs == 1)
 313     {
 314         nhs[0] = raw_next_hops[0];
 315         nhs[0].path_weight = 1;
 316         _vec_len (nhs) = 1;
 317         sum_weight = 1;
 318         goto done;
 319     }
 320
 321     else if (n_nhs == 2)
 322     {
 323         int cmp = next_hop_sort_by_weight (&raw_next_hops[0], &raw_next_hops[1]) < 0;
 324
 325         /* Fast sort. */
 326         nhs[0] = raw_next_hops[cmp];
 327         nhs[1] = raw_next_hops[cmp ^ 1];
 328
 329         /* Fast path: equal cost multipath with 2 next hops. */
 330         if (nhs[0].path_weight == nhs[1].path_weight)
 331         {
 332             nhs[0].path_weight = nhs[1].path_weight = 1;
 333             _vec_len (nhs) = 2;
 334             sum_weight = 2;
 335             goto done;
 336         }
 337     }
 338     else
 339     {
 340         clib_memcpy (nhs, raw_next_hops, n_nhs * sizeof (raw_next_hops[0]));
 341         qsort (nhs, n_nhs, sizeof (nhs[0]), (void *) next_hop_sort_by_weight);
 342     }
 343
 344     /* Find total weight to normalize weights. */
 345     sum_weight = 0;
 346     for (i = 0; i < n_nhs; i++)
 347         sum_weight += nhs[i].path_weight;
 348
 349     /* In the unlikely case that all weights are given as 0, set them all to 1. */
 350     if (sum_weight == 0)
 351     {
 352         for (i = 0; i < n_nhs; i++)
 353             nhs[i].path_weight = 1;
 354         sum_weight = n_nhs;
 355     }
 356
 357     /* Save copies of all next hop weights to avoid being overwritten in loop below. */
 358     for (i = 0; i < n_nhs; i++)
 359         nhs[n_nhs + i].path_weight = nhs[i].path_weight;
 360
 361     /* Try larger and larger power of 2 sized adjacency blocks until we
 362        find one where traffic flows to within 1% of specified weights. */
 363     for (n_adj = max_pow2 (n_nhs); ; n_adj *= 2)
 364     {
 365         error = 0;
 366
 367         norm = n_adj / ((f64) sum_weight);
 368         n_adj_left = n_adj;
 369         for (i = 0; i < n_nhs; i++)
 370         {
 371             f64 nf = nhs[n_nhs + i].path_weight * norm; /* use saved weights */
 372             word n = flt_round_nearest (nf);
 373
 374             n = n > n_adj_left ? n_adj_left : n;
 375             n_adj_left -= n;
 376             error += fabs (nf - n);
 377             nhs[i].path_weight = n;
 378
 379             if (0 == nhs[i].path_weight)
 380             {
 381                 /*
 382                  * when the weight skew is high (norm is small) and n == nf.
 383                  * without this correction the path with a low weight would have
 384                  * no represenation in the load-balanace - don't want that.
 385                  * If the weight skew is high so the load-balance has many buckets
 386                  * to allow it. pays ya money takes ya choice.
 387                  */
 388                 error = n_adj;
 389                 break;
 390             }
 391         }
 392
 393         nhs[0].path_weight += n_adj_left;
 394
 395         /* Less than 5% average error per adjacency with this size adjacency block? */
 396         if (error <= multipath_next_hop_error_tolerance*n_adj)
 397         {
 398             /* Truncate any next hops with zero weight. */
 399             _vec_len (nhs) = i;
 400             break;
 401         }
 402     }
 403
 404 done:
 405     /* Save vector for next call. */
 406     *normalized_next_hops = nhs;
 407     *sum_weight_in = sum_weight;
 408     return n_adj;
 409 }
 410
 411 static load_balance_path_t *
 412 load_balance_multipath_next_hop_fixup (load_balance_path_t *nhs,
 413                                        dpo_proto_t drop_proto)
 414 {
 415     if (0 == vec_len(nhs))
 416     {
 417         load_balance_path_t *nh;
 418
 419         /*
 420          * we need something for the load-balance. so use the drop
 421          */
 422         vec_add2(nhs, nh, 1);
 423
 424         nh->path_weight = 1;
 425         dpo_copy(&nh->path_dpo, drop_dpo_get(drop_proto));
 426     }
 427
 428     return (nhs);
 429 }
 430
 431 /*
 432  * Fill in adjacencies in block based on corresponding
 433  * next hop adjacencies.
 434  */
 435 static void
 436 load_balance_fill_buckets (load_balance_t *lb,
 437                            load_balance_path_t *nhs,
 438                            dpo_id_t *buckets,
 439                            u32 n_buckets)
 440 {
 441     load_balance_path_t * nh;
 442     u16 ii, bucket;
 443
 444     bucket = 0;
 445
 446     /*
 447      * the next-hops have normalised weights. that means their sum is the number
 448      * of buckets we need to fill.
 449      */
 450     vec_foreach (nh, nhs)
 451     {
 452         for (ii = 0; ii < nh->path_weight; ii++)
 453         {
 454             ASSERT(bucket < n_buckets);
 455             load_balance_set_bucket_i(lb, bucket++, buckets, &nh->path_dpo);
 456         }
 457     }
 458 }
 459
 460 static inline void
 461 load_balance_set_n_buckets (load_balance_t *lb,
 462                             u32 n_buckets)
 463 {
 464     lb->lb_n_buckets = n_buckets;
 465     lb->lb_n_buckets_minus_1 = n_buckets-1;
 466 }
 467
 468 void
 469 load_balance_multipath_update (const dpo_id_t *dpo,
 470                                load_balance_path_t * raw_next_hops,
 471                                load_balance_flags_t flags)
 472 {
 473     u32 sum_of_weights,n_buckets, ii;
 474     load_balance_path_t * nh, * nhs;
 475     index_t lbmi, old_lbmi;
 476     load_balance_t *lb;
 477     dpo_id_t *tmp_dpo;
 478
 479     nhs = NULL;
 480
 481     ASSERT(DPO_LOAD_BALANCE == dpo->dpoi_type);
 482     lb = load_balance_get(dpo->dpoi_index);
 483     raw_next_hops =
 484         load_balance_multipath_next_hop_fixup(raw_next_hops,
 485                                               lb->lb_proto);
 486     n_buckets =
 487         ip_multipath_normalize_next_hops(raw_next_hops,
 488                                          &nhs,
 489                                          &sum_of_weights,
 490                                          multipath_next_hop_error_tolerance);
 491
 492     ASSERT (n_buckets >= vec_len (raw_next_hops));
 493
 494     /*
 495      * Save the old load-balance map used, and get a new one if required.
 496      */
 497     old_lbmi = lb->lb_map;
 498     if (flags & LOAD_BALANCE_FLAG_USES_MAP)
 499     {
 500         lbmi = load_balance_map_add_or_lock(n_buckets, sum_of_weights, nhs);
 501     }
 502     else
 503     {
 504         lbmi = INDEX_INVALID;
 505     }
 506
 507     if (0 == lb->lb_n_buckets)
 508     {
 509         /*
 510          * first time initialisation. no packets inflight, so we can write
 511          * at leisure.
 512          */
 513         load_balance_set_n_buckets(lb, n_buckets);
 514
 515         if (!LB_HAS_INLINE_BUCKETS(lb))
 516             vec_validate_aligned(lb->lb_buckets,
 517                                  lb->lb_n_buckets - 1,
 518                                  CLIB_CACHE_LINE_BYTES);
 519
 520         load_balance_fill_buckets(lb, nhs,
 521                                   load_balance_get_buckets(lb),
 522                                   n_buckets);
 523         lb->lb_map = lbmi;
 524     }
 525     else
 526     {
 527         /*
 528          * This is a modification of an existing load-balance.
 529          * We need to ensure that packets inflight see a consistent state, that
 530          * is the number of reported buckets the LB has (read from
 531          * lb_n_buckets_minus_1) is not more than it actually has. So if the
 532          * number of buckets is increasing, we must update the bucket array first,
 533          * then the reported number. vice-versa if the number of buckets goes down.
 534          */
 535         if (n_buckets == lb->lb_n_buckets)
 536         {
 537             /*
 538              * no change in the number of buckets. we can simply fill what
 539              * is new over what is old.
 540              */
 541             load_balance_fill_buckets(lb, nhs,
 542                                       load_balance_get_buckets(lb),
 543                                       n_buckets);
 544             lb->lb_map = lbmi;
 545         }
 546         else if (n_buckets > lb->lb_n_buckets)
 547         {
 548             /*
 549              * we have more buckets. the old load-balance map (if there is one)
 550              * will remain valid, i.e. mapping to indices within range, so we
 551              * update it last.
 552              */
 553             if (n_buckets > LB_NUM_INLINE_BUCKETS &&
 554                 lb->lb_n_buckets <= LB_NUM_INLINE_BUCKETS)
 555             {
 556                 /*
 557                  * the new increased number of buckets is crossing the threshold
 558                  * from the inline storage to out-line. Alloc the outline buckets
 559                  * first, then fixup the number. then reset the inlines.
 560                  */
 561                 ASSERT(NULL == lb->lb_buckets);
 562                 vec_validate_aligned(lb->lb_buckets,
 563                                      n_buckets - 1,
 564                                      CLIB_CACHE_LINE_BYTES);
 565
 566                 load_balance_fill_buckets(lb, nhs,
 567                                           lb->lb_buckets,
 568                                           n_buckets);
 569                 CLIB_MEMORY_BARRIER();
 570                 load_balance_set_n_buckets(lb, n_buckets);
 571
 572                 CLIB_MEMORY_BARRIER();
 573
 574                 for (ii = 0; ii < LB_NUM_INLINE_BUCKETS; ii++)
 575                 {
 576                     dpo_reset(&lb->lb_buckets_inline[ii]);
 577                 }
 578             }
 579             else
 580             {
 581                 if (n_buckets <= LB_NUM_INLINE_BUCKETS)
 582                 {
 583                     /*
 584                      * we are not crossing the threshold and it's still inline buckets.
 585                      * we can write the new on the old..
 586                      */
 587                     load_balance_fill_buckets(lb, nhs,
 588                                               load_balance_get_buckets(lb),
 589                                               n_buckets);
 590                     CLIB_MEMORY_BARRIER();
 591                     load_balance_set_n_buckets(lb, n_buckets);
 592                 }
 593                 else
 594                 {
 595                     /*
 596                      * we are not crossing the threshold. We need a new bucket array to
 597                      * hold the increased number of choices.
 598                      */
 599                     dpo_id_t *new_buckets, *old_buckets, *tmp_dpo;
 600
 601                     new_buckets = NULL;
 602                     old_buckets = load_balance_get_buckets(lb);
 603
 604                     vec_validate_aligned(new_buckets,
 605                                          n_buckets - 1,
 606                                          CLIB_CACHE_LINE_BYTES);
 607
 608                     load_balance_fill_buckets(lb, nhs, new_buckets, n_buckets);
 609                     CLIB_MEMORY_BARRIER();
 610                     lb->lb_buckets = new_buckets;
 611                     CLIB_MEMORY_BARRIER();
 612                     load_balance_set_n_buckets(lb, n_buckets);
 613
 614                     vec_foreach(tmp_dpo, old_buckets)
 615                     {
 616                         dpo_reset(tmp_dpo);
 617                     }
 618                     vec_free(old_buckets);
 619                 }
 620             }
 621
 622             /*
 623              * buckets fixed. ready for the MAP update.
 624              */
 625             lb->lb_map = lbmi;
 626         }
 627         else
 628         {
 629             /*
 630              * bucket size shrinkage.
 631              * Any map we have will be based on the old
 632              * larger number of buckets, so will be translating to indices
 633              * out of range. So the new MAP must be installed first.
 634              */
 635             lb->lb_map = lbmi;
 636             CLIB_MEMORY_BARRIER();
 637
 638
 639             if (n_buckets <= LB_NUM_INLINE_BUCKETS &&
 640                 lb->lb_n_buckets > LB_NUM_INLINE_BUCKETS)
 641             {
 642                 /*
 643                  * the new decreased number of buckets is crossing the threshold
 644                  * from out-line storage to inline:
 645                  *   1 - Fill the inline buckets,
 646                  *   2 - fixup the number (and this point the inline buckets are
 647                  *       used).
 648                  *   3 - free the outline buckets
 649                  */
 650                 load_balance_fill_buckets(lb, nhs,
 651                                           lb->lb_buckets_inline,
 652                                           n_buckets);
 653                 CLIB_MEMORY_BARRIER();
 654                 load_balance_set_n_buckets(lb, n_buckets);
 655                 CLIB_MEMORY_BARRIER();
 656
 657                 vec_foreach(tmp_dpo, lb->lb_buckets)
 658                 {
 659                     dpo_reset(tmp_dpo);
 660                 }
 661                 vec_free(lb->lb_buckets);
 662             }
 663             else
 664             {
 665                 /*
 666                  * not crossing the threshold.
 667                  *  1 - update the number to the smaller size
 668                  *  2 - write the new buckets
 669                  *  3 - reset those no longer used.
 670                  */
 671                 dpo_id_t *buckets;
 672                 u32 old_n_buckets;
 673
 674                 old_n_buckets = lb->lb_n_buckets;
 675                 buckets = load_balance_get_buckets(lb);
 676
 677                 load_balance_set_n_buckets(lb, n_buckets);
 678                 CLIB_MEMORY_BARRIER();
 679
 680                 load_balance_fill_buckets(lb, nhs,
 681                                           buckets,
 682                                           n_buckets);
 683
 684                 for (ii = old_n_buckets-n_buckets; ii < old_n_buckets; ii++)
 685                 {
 686                     dpo_reset(&buckets[ii]);
 687                 }
 688             }
 689         }
 690     }
 691
 692     vec_foreach (nh, nhs)
 693     {
 694         dpo_reset(&nh->path_dpo);
 695     }
 696     vec_free(nhs);
 697
 698     load_balance_map_unlock(old_lbmi);
 699 }
 700
 701 static void
 702 load_balance_lock (dpo_id_t *dpo)
 703 {
 704     load_balance_t *lb;
 705
 706     lb = load_balance_get(dpo->dpoi_index);
 707
 708     lb->lb_locks++;
 709 }
 710
 711 static void
 712 load_balance_destroy (load_balance_t *lb)
 713 {
 714     dpo_id_t *buckets;
 715     int i;
 716
 717     buckets = load_balance_get_buckets(lb);
 718
 719     for (i = 0; i < lb->lb_n_buckets; i++)
 720     {
 721         dpo_reset(&buckets[i]);
 722     }
 723
 724     LB_DBG(lb, "destroy");
 725     if (!LB_HAS_INLINE_BUCKETS(lb))
 726     {
 727         vec_free(lb->lb_buckets);
 728     }
 729
 730     fib_urpf_list_unlock(lb->lb_urpf);
 731     load_balance_map_unlock(lb->lb_map);
 732
 733     pool_put(load_balance_pool, lb);
 734 }
 735
 736 static void
 737 load_balance_unlock (dpo_id_t *dpo)
 738 {
 739     load_balance_t *lb;
 740
 741     lb = load_balance_get(dpo->dpoi_index);
 742
 743     lb->lb_locks--;
 744
 745     if (0 == lb->lb_locks)
 746     {
 747         load_balance_destroy(lb);
 748     }
 749 }
 750
 751 static void
 752 load_balance_mem_show (void)
 753 {
 754     fib_show_memory_usage("load-balance",
 755                           pool_elts(load_balance_pool),
 756                           pool_len(load_balance_pool),
 757                           sizeof(load_balance_t));
 758     load_balance_map_show_mem();
 759 }
 760
 761 const static dpo_vft_t lb_vft = {
 762     .dv_lock = load_balance_lock,
 763     .dv_unlock = load_balance_unlock,
 764     .dv_format = format_load_balance_dpo,
 765     .dv_mem_show = load_balance_mem_show,
 766 };
 767
 768 /**
 769  * @brief The per-protocol VLIB graph nodes that are assigned to a load-balance
 770  *        object.
 771  *
 772  * this means that these graph nodes are ones from which a load-balance is the
 773  * parent object in the DPO-graph.
 774  *
 775  * We do not list all the load-balance nodes, such as the *-lookup. instead
 776  * we are relying on the correct use of the .sibling_of field when setting
 777  * up these sibling nodes.
 778  */
 779 const static char* const load_balance_ip4_nodes[] =
 780 {
 781     "ip4-load-balance",
 782     NULL,
 783 };
 784 const static char* const load_balance_ip6_nodes[] =
 785 {
 786     "ip6-load-balance",
 787     NULL,
 788 };
 789 const static char* const load_balance_mpls_nodes[] =
 790 {
 791     "mpls-load-balance",
 792     NULL,
 793 };
 794 const static char* const load_balance_l2_nodes[] =
 795 {
 796     "l2-load-balance",
 797     NULL,
 798 };
 799 const static char* const * const load_balance_nodes[DPO_PROTO_NUM] =
 800 {
 801     [DPO_PROTO_IP4]  = load_balance_ip4_nodes,
 802     [DPO_PROTO_IP6]  = load_balance_ip6_nodes,
 803     [DPO_PROTO_MPLS] = load_balance_mpls_nodes,
 804     [DPO_PROTO_ETHERNET] = load_balance_l2_nodes,
 805 };
 806
 807 void
 808 load_balance_module_init (void)
 809 {
 810     dpo_register(DPO_LOAD_BALANCE, &lb_vft, load_balance_nodes);
 811
 812     load_balance_map_module_init();
 813 }
 814
 815 static clib_error_t *
 816 load_balance_show (vlib_main_t * vm,
 817                    unformat_input_t * input,
 818                    vlib_cli_command_t * cmd)
 819 {
 820     index_t lbi = INDEX_INVALID;
 821
 822     while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
 823     {
 824         if (unformat (input, "%d", &lbi))
 825             ;
 826         else
 827             break;
 828     }
 829
 830     if (INDEX_INVALID != lbi)
 831     {
 832         vlib_cli_output (vm, "%U", format_load_balance, lbi,
 833                          LOAD_BALANCE_FORMAT_DETAIL);
 834     }
 835     else
 836     {
 837         load_balance_t *lb;
 838
 839         pool_foreach(lb, load_balance_pool,
 840         ({
 841             vlib_cli_output (vm, "%U", format_load_balance,
 842                              load_balance_get_index(lb),
 843                              LOAD_BALANCE_FORMAT_NONE);
 844         }));
 845     }
 846
 847     return 0;
 848 }
 849
 850 VLIB_CLI_COMMAND (load_balance_show_command, static) = {
 851     .path = "show load-balance",
 852     .short_help = "show load-balance [<index>]",
 853     .function = load_balance_show,
 854 };
 855
 856
 857 always_inline u32
 858 ip_flow_hash (void *data)
 859 {
 860   ip4_header_t *iph = (ip4_header_t *) data;
 861
 862   if ((iph->ip_version_and_header_length & 0xF0) == 0x40)
 863     return ip4_compute_flow_hash (iph, IP_FLOW_HASH_DEFAULT);
 864   else
 865     return ip6_compute_flow_hash ((ip6_header_t *) iph, IP_FLOW_HASH_DEFAULT);
 866 }
 867
 868 always_inline u64
 869 mac_to_u64 (u8 * m)
 870 {
 871   return (*((u64 *) m) & 0xffffffffffff);
 872 }
 873
 874 always_inline u32
 875 l2_flow_hash (vlib_buffer_t * b0)
 876 {
 877   ethernet_header_t *eh;
 878   u64 a, b, c;
 879   uword is_ip, eh_size;
 880   u16 eh_type;
 881
 882   eh = vlib_buffer_get_current (b0);
 883   eh_type = clib_net_to_host_u16 (eh->type);
 884   eh_size = ethernet_buffer_header_size (b0);
 885
 886   is_ip = (eh_type == ETHERNET_TYPE_IP4 || eh_type == ETHERNET_TYPE_IP6);
 887
 888   /* since we have 2 cache lines, use them */
 889   if (is_ip)
 890     a = ip_flow_hash ((u8 *) vlib_buffer_get_current (b0) + eh_size);
 891   else
 892     a = eh->type;
 893
 894   b = mac_to_u64 ((u8 *) eh->dst_address);
 895   c = mac_to_u64 ((u8 *) eh->src_address);
 896   hash_mix64 (a, b, c);
 897
 898   return (u32) c;
 899 }
 900
 901 typedef struct load_balance_trace_t_
 902 {
 903     index_t lb_index;
 904 } load_balance_trace_t;
 905
 906 static uword
 907 l2_load_balance (vlib_main_t * vm,
 908                  vlib_node_runtime_t * node,
 909                  vlib_frame_t * frame)
 910 {
 911   u32 n_left_from, next_index, *from, *to_next;
 912
 913   from = vlib_frame_vector_args (frame);
 914   n_left_from = frame->n_vectors;
 915
 916   next_index = node->cached_next_index;
 917
 918   while (n_left_from > 0)
 919     {
 920       u32 n_left_to_next;
 921
 922       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 923
 924       while (n_left_from > 0 && n_left_to_next > 0)
 925         {
 926           vlib_buffer_t *b0;
 927           u32 bi0, lbi0, next0;
 928           const dpo_id_t *dpo0;
 929           const load_balance_t *lb0;
 930
 931           bi0 = from[0];
 932           to_next[0] = bi0;
 933           from += 1;
 934           to_next += 1;
 935           n_left_from -= 1;
 936           n_left_to_next -= 1;
 937
 938           b0 = vlib_get_buffer (vm, bi0);
 939
 940           /* lookup dst + src mac */
 941           lbi0 =  vnet_buffer (b0)->ip.adj_index[VLIB_TX];
 942           lb0 = load_balance_get(lbi0);
 943
 944           vnet_buffer(b0)->ip.flow_hash = l2_flow_hash(b0);
 945
 946           dpo0 = load_balance_get_bucket_i(lb0,
 947                                            vnet_buffer(b0)->ip.flow_hash &
 948                                            (lb0->lb_n_buckets_minus_1));
 949
 950           next0 = dpo0->dpoi_next_node;
 951           vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 952
 953           if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 954             {
 955               load_balance_trace_t *tr = vlib_add_trace (vm, node, b0,
 956                                                          sizeof (*tr));
 957               tr->lb_index = lbi0;
 958             }
 959           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 960                                            n_left_to_next, bi0, next0);
 961         }
 962
 963       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 964     }
 965
 966   return frame->n_vectors;
 967 }
 968
 969 static u8 *
 970 format_load_balance_trace (u8 * s, va_list * args)
 971 {
 972   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
 973   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
 974   load_balance_trace_t *t = va_arg (*args, load_balance_trace_t *);
 975
 976   s = format (s, "L2-load-balance: index %d", t->lb_index);
 977   return s;
 978 }
 979
 980 /**
 981  * @brief
 982  */
 983 VLIB_REGISTER_NODE (l2_load_balance_node) = {
 984   .function = l2_load_balance,
 985   .name = "l2-load-balance",
 986   .vector_size = sizeof (u32),
 987
 988   .format_trace = format_load_balance_trace,
 989   .n_next_nodes = 1,
 990   .next_nodes = {
 991       [0] = "error-drop",
 992   },
 993 };