src/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 (const load_balance_path_t * n1,
 283                          const 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 (const 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 (const load_balance_path_t *nhs,
 413                                        dpo_proto_t drop_proto)
 414 {
 415     if (0 == vec_len(nhs))
 416     {
 417         load_balance_path_t *new_nhs = NULL, *nh;
 418
 419         /*
 420          * we need something for the load-balance. so use the drop
 421          */
 422         vec_add2(new_nhs, nh, 1);
 423
 424         nh->path_weight = 1;
 425         dpo_copy(&nh->path_dpo, drop_dpo_get(drop_proto));
 426
 427         return (new_nhs);
 428     }
 429
 430     return (NULL);
 431 }
 432
 433 /*
 434  * Fill in adjacencies in block based on corresponding
 435  * next hop adjacencies.
 436  */
 437 static void
 438 load_balance_fill_buckets (load_balance_t *lb,
 439                            load_balance_path_t *nhs,
 440                            dpo_id_t *buckets,
 441                            u32 n_buckets)
 442 {
 443     load_balance_path_t * nh;
 444     u16 ii, bucket;
 445
 446     bucket = 0;
 447
 448     /*
 449      * the next-hops have normalised weights. that means their sum is the number
 450      * of buckets we need to fill.
 451      */
 452     vec_foreach (nh, nhs)
 453     {
 454         for (ii = 0; ii < nh->path_weight; ii++)
 455         {
 456             ASSERT(bucket < n_buckets);
 457             load_balance_set_bucket_i(lb, bucket++, buckets, &nh->path_dpo);
 458         }
 459     }
 460 }
 461
 462 static inline void
 463 load_balance_set_n_buckets (load_balance_t *lb,
 464                             u32 n_buckets)
 465 {
 466     lb->lb_n_buckets = n_buckets;
 467     lb->lb_n_buckets_minus_1 = n_buckets-1;
 468 }
 469
 470 void
 471 load_balance_multipath_update (const dpo_id_t *dpo,
 472                                const load_balance_path_t * raw_nhs,
 473                                load_balance_flags_t flags)
 474 {
 475     load_balance_path_t *nh, *nhs, *fixed_nhs;
 476     u32 sum_of_weights, n_buckets, ii;
 477     index_t lbmi, old_lbmi;
 478     load_balance_t *lb;
 479     dpo_id_t *tmp_dpo;
 480
 481     nhs = NULL;
 482
 483     ASSERT(DPO_LOAD_BALANCE == dpo->dpoi_type);
 484     lb = load_balance_get(dpo->dpoi_index);
 485     fixed_nhs = load_balance_multipath_next_hop_fixup(raw_nhs, lb->lb_proto);
 486     n_buckets =
 487         ip_multipath_normalize_next_hops((NULL == fixed_nhs ?
 488                                           raw_nhs :
 489                                           fixed_nhs),
 490                                          &nhs,
 491                                          &sum_of_weights,
 492                                          multipath_next_hop_error_tolerance);
 493
 494     ASSERT (n_buckets >= vec_len (raw_nhs));
 495
 496     /*
 497      * Save the old load-balance map used, and get a new one if required.
 498      */
 499     old_lbmi = lb->lb_map;
 500     if (flags & LOAD_BALANCE_FLAG_USES_MAP)
 501     {
 502         lbmi = load_balance_map_add_or_lock(n_buckets, sum_of_weights, nhs);
 503     }
 504     else
 505     {
 506         lbmi = INDEX_INVALID;
 507     }
 508
 509     if (0 == lb->lb_n_buckets)
 510     {
 511         /*
 512          * first time initialisation. no packets inflight, so we can write
 513          * at leisure.
 514          */
 515         load_balance_set_n_buckets(lb, n_buckets);
 516
 517         if (!LB_HAS_INLINE_BUCKETS(lb))
 518             vec_validate_aligned(lb->lb_buckets,
 519                                  lb->lb_n_buckets - 1,
 520                                  CLIB_CACHE_LINE_BYTES);
 521
 522         load_balance_fill_buckets(lb, nhs,
 523                                   load_balance_get_buckets(lb),
 524                                   n_buckets);
 525         lb->lb_map = lbmi;
 526     }
 527     else
 528     {
 529         /*
 530          * This is a modification of an existing load-balance.
 531          * We need to ensure that packets inflight see a consistent state, that
 532          * is the number of reported buckets the LB has (read from
 533          * lb_n_buckets_minus_1) is not more than it actually has. So if the
 534          * number of buckets is increasing, we must update the bucket array first,
 535          * then the reported number. vice-versa if the number of buckets goes down.
 536          */
 537         if (n_buckets == lb->lb_n_buckets)
 538         {
 539             /*
 540              * no change in the number of buckets. we can simply fill what
 541              * is new over what is old.
 542              */
 543             load_balance_fill_buckets(lb, nhs,
 544                                       load_balance_get_buckets(lb),
 545                                       n_buckets);
 546             lb->lb_map = lbmi;
 547         }
 548         else if (n_buckets > lb->lb_n_buckets)
 549         {
 550             /*
 551              * we have more buckets. the old load-balance map (if there is one)
 552              * will remain valid, i.e. mapping to indices within range, so we
 553              * update it last.
 554              */
 555             if (n_buckets > LB_NUM_INLINE_BUCKETS &&
 556                 lb->lb_n_buckets <= LB_NUM_INLINE_BUCKETS)
 557             {
 558                 /*
 559                  * the new increased number of buckets is crossing the threshold
 560                  * from the inline storage to out-line. Alloc the outline buckets
 561                  * first, then fixup the number. then reset the inlines.
 562                  */
 563                 ASSERT(NULL == lb->lb_buckets);
 564                 vec_validate_aligned(lb->lb_buckets,
 565                                      n_buckets - 1,
 566                                      CLIB_CACHE_LINE_BYTES);
 567
 568                 load_balance_fill_buckets(lb, nhs,
 569                                           lb->lb_buckets,
 570                                           n_buckets);
 571                 CLIB_MEMORY_BARRIER();
 572                 load_balance_set_n_buckets(lb, n_buckets);
 573
 574                 CLIB_MEMORY_BARRIER();
 575
 576                 for (ii = 0; ii < LB_NUM_INLINE_BUCKETS; ii++)
 577                 {
 578                     dpo_reset(&lb->lb_buckets_inline[ii]);
 579                 }
 580             }
 581             else
 582             {
 583                 if (n_buckets <= LB_NUM_INLINE_BUCKETS)
 584                 {
 585                     /*
 586                      * we are not crossing the threshold and it's still inline buckets.
 587                      * we can write the new on the old..
 588                      */
 589                     load_balance_fill_buckets(lb, nhs,
 590                                               load_balance_get_buckets(lb),
 591                                               n_buckets);
 592                     CLIB_MEMORY_BARRIER();
 593                     load_balance_set_n_buckets(lb, n_buckets);
 594                 }
 595                 else
 596                 {
 597                     /*
 598                      * we are not crossing the threshold. We need a new bucket array to
 599                      * hold the increased number of choices.
 600                      */
 601                     dpo_id_t *new_buckets, *old_buckets, *tmp_dpo;
 602
 603                     new_buckets = NULL;
 604                     old_buckets = load_balance_get_buckets(lb);
 605
 606                     vec_validate_aligned(new_buckets,
 607                                          n_buckets - 1,
 608                                          CLIB_CACHE_LINE_BYTES);
 609
 610                     load_balance_fill_buckets(lb, nhs, new_buckets, n_buckets);
 611                     CLIB_MEMORY_BARRIER();
 612                     lb->lb_buckets = new_buckets;
 613                     CLIB_MEMORY_BARRIER();
 614                     load_balance_set_n_buckets(lb, n_buckets);
 615
 616                     vec_foreach(tmp_dpo, old_buckets)
 617                     {
 618                         dpo_reset(tmp_dpo);
 619                     }
 620                     vec_free(old_buckets);
 621                 }
 622             }
 623
 624             /*
 625              * buckets fixed. ready for the MAP update.
 626              */
 627             lb->lb_map = lbmi;
 628         }
 629         else
 630         {
 631             /*
 632              * bucket size shrinkage.
 633              * Any map we have will be based on the old
 634              * larger number of buckets, so will be translating to indices
 635              * out of range. So the new MAP must be installed first.
 636              */
 637             lb->lb_map = lbmi;
 638             CLIB_MEMORY_BARRIER();
 639
 640
 641             if (n_buckets <= LB_NUM_INLINE_BUCKETS &&
 642                 lb->lb_n_buckets > LB_NUM_INLINE_BUCKETS)
 643             {
 644                 /*
 645                  * the new decreased number of buckets is crossing the threshold
 646                  * from out-line storage to inline:
 647                  *   1 - Fill the inline buckets,
 648                  *   2 - fixup the number (and this point the inline buckets are
 649                  *       used).
 650                  *   3 - free the outline buckets
 651                  */
 652                 load_balance_fill_buckets(lb, nhs,
 653                                           lb->lb_buckets_inline,
 654                                           n_buckets);
 655                 CLIB_MEMORY_BARRIER();
 656                 load_balance_set_n_buckets(lb, n_buckets);
 657                 CLIB_MEMORY_BARRIER();
 658
 659                 vec_foreach(tmp_dpo, lb->lb_buckets)
 660                 {
 661                     dpo_reset(tmp_dpo);
 662                 }
 663                 vec_free(lb->lb_buckets);
 664             }
 665             else
 666             {
 667                 /*
 668                  * not crossing the threshold.
 669                  *  1 - update the number to the smaller size
 670                  *  2 - write the new buckets
 671                  *  3 - reset those no longer used.
 672                  */
 673                 dpo_id_t *buckets;
 674                 u32 old_n_buckets;
 675
 676                 old_n_buckets = lb->lb_n_buckets;
 677                 buckets = load_balance_get_buckets(lb);
 678
 679                 load_balance_set_n_buckets(lb, n_buckets);
 680                 CLIB_MEMORY_BARRIER();
 681
 682                 load_balance_fill_buckets(lb, nhs,
 683                                           buckets,
 684                                           n_buckets);
 685
 686                 for (ii = old_n_buckets-n_buckets; ii < old_n_buckets; ii++)
 687                 {
 688                     dpo_reset(&buckets[ii]);
 689                 }
 690             }
 691         }
 692     }
 693
 694     vec_foreach (nh, nhs)
 695     {
 696         dpo_reset(&nh->path_dpo);
 697     }
 698     vec_free(nhs);
 699     vec_free(fixed_nhs);
 700
 701     load_balance_map_unlock(old_lbmi);
 702 }
 703
 704 static void
 705 load_balance_lock (dpo_id_t *dpo)
 706 {
 707     load_balance_t *lb;
 708
 709     lb = load_balance_get(dpo->dpoi_index);
 710
 711     lb->lb_locks++;
 712 }
 713
 714 static void
 715 load_balance_destroy (load_balance_t *lb)
 716 {
 717     dpo_id_t *buckets;
 718     int i;
 719
 720     buckets = load_balance_get_buckets(lb);
 721
 722     for (i = 0; i < lb->lb_n_buckets; i++)
 723     {
 724         dpo_reset(&buckets[i]);
 725     }
 726
 727     LB_DBG(lb, "destroy");
 728     if (!LB_HAS_INLINE_BUCKETS(lb))
 729     {
 730         vec_free(lb->lb_buckets);
 731     }
 732
 733     fib_urpf_list_unlock(lb->lb_urpf);
 734     load_balance_map_unlock(lb->lb_map);
 735
 736     pool_put(load_balance_pool, lb);
 737 }
 738
 739 static void
 740 load_balance_unlock (dpo_id_t *dpo)
 741 {
 742     load_balance_t *lb;
 743
 744     lb = load_balance_get(dpo->dpoi_index);
 745
 746     lb->lb_locks--;
 747
 748     if (0 == lb->lb_locks)
 749     {
 750         load_balance_destroy(lb);
 751     }
 752 }
 753
 754 static void
 755 load_balance_mem_show (void)
 756 {
 757     fib_show_memory_usage("load-balance",
 758                           pool_elts(load_balance_pool),
 759                           pool_len(load_balance_pool),
 760                           sizeof(load_balance_t));
 761     load_balance_map_show_mem();
 762 }
 763
 764 const static dpo_vft_t lb_vft = {
 765     .dv_lock = load_balance_lock,
 766     .dv_unlock = load_balance_unlock,
 767     .dv_format = format_load_balance_dpo,
 768     .dv_mem_show = load_balance_mem_show,
 769 };
 770
 771 /**
 772  * @brief The per-protocol VLIB graph nodes that are assigned to a load-balance
 773  *        object.
 774  *
 775  * this means that these graph nodes are ones from which a load-balance is the
 776  * parent object in the DPO-graph.
 777  *
 778  * We do not list all the load-balance nodes, such as the *-lookup. instead
 779  * we are relying on the correct use of the .sibling_of field when setting
 780  * up these sibling nodes.
 781  */
 782 const static char* const load_balance_ip4_nodes[] =
 783 {
 784     "ip4-load-balance",
 785     NULL,
 786 };
 787 const static char* const load_balance_ip6_nodes[] =
 788 {
 789     "ip6-load-balance",
 790     NULL,
 791 };
 792 const static char* const load_balance_mpls_nodes[] =
 793 {
 794     "mpls-load-balance",
 795     NULL,
 796 };
 797 const static char* const load_balance_l2_nodes[] =
 798 {
 799     "l2-load-balance",
 800     NULL,
 801 };
 802 const static char* const * const load_balance_nodes[DPO_PROTO_NUM] =
 803 {
 804     [DPO_PROTO_IP4]  = load_balance_ip4_nodes,
 805     [DPO_PROTO_IP6]  = load_balance_ip6_nodes,
 806     [DPO_PROTO_MPLS] = load_balance_mpls_nodes,
 807     [DPO_PROTO_ETHERNET] = load_balance_l2_nodes,
 808 };
 809
 810 void
 811 load_balance_module_init (void)
 812 {
 813     dpo_register(DPO_LOAD_BALANCE, &lb_vft, load_balance_nodes);
 814
 815     load_balance_map_module_init();
 816 }
 817
 818 static clib_error_t *
 819 load_balance_show (vlib_main_t * vm,
 820                    unformat_input_t * input,
 821                    vlib_cli_command_t * cmd)
 822 {
 823     index_t lbi = INDEX_INVALID;
 824
 825     while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
 826     {
 827         if (unformat (input, "%d", &lbi))
 828             ;
 829         else
 830             break;
 831     }
 832
 833     if (INDEX_INVALID != lbi)
 834     {
 835         vlib_cli_output (vm, "%U", format_load_balance, lbi,
 836                          LOAD_BALANCE_FORMAT_DETAIL);
 837     }
 838     else
 839     {
 840         load_balance_t *lb;
 841
 842         pool_foreach(lb, load_balance_pool,
 843         ({
 844             vlib_cli_output (vm, "%U", format_load_balance,
 845                              load_balance_get_index(lb),
 846                              LOAD_BALANCE_FORMAT_NONE);
 847         }));
 848     }
 849
 850     return 0;
 851 }
 852
 853 VLIB_CLI_COMMAND (load_balance_show_command, static) = {
 854     .path = "show load-balance",
 855     .short_help = "show load-balance [<index>]",
 856     .function = load_balance_show,
 857 };
 858
 859
 860 always_inline u32
 861 ip_flow_hash (void *data)
 862 {
 863   ip4_header_t *iph = (ip4_header_t *) data;
 864
 865   if ((iph->ip_version_and_header_length & 0xF0) == 0x40)
 866     return ip4_compute_flow_hash (iph, IP_FLOW_HASH_DEFAULT);
 867   else
 868     return ip6_compute_flow_hash ((ip6_header_t *) iph, IP_FLOW_HASH_DEFAULT);
 869 }
 870
 871 always_inline u64
 872 mac_to_u64 (u8 * m)
 873 {
 874   return (*((u64 *) m) & 0xffffffffffff);
 875 }
 876
 877 always_inline u32
 878 l2_flow_hash (vlib_buffer_t * b0)
 879 {
 880   ethernet_header_t *eh;
 881   u64 a, b, c;
 882   uword is_ip, eh_size;
 883   u16 eh_type;
 884
 885   eh = vlib_buffer_get_current (b0);
 886   eh_type = clib_net_to_host_u16 (eh->type);
 887   eh_size = ethernet_buffer_header_size (b0);
 888
 889   is_ip = (eh_type == ETHERNET_TYPE_IP4 || eh_type == ETHERNET_TYPE_IP6);
 890
 891   /* since we have 2 cache lines, use them */
 892   if (is_ip)
 893     a = ip_flow_hash ((u8 *) vlib_buffer_get_current (b0) + eh_size);
 894   else
 895     a = eh->type;
 896
 897   b = mac_to_u64 ((u8 *) eh->dst_address);
 898   c = mac_to_u64 ((u8 *) eh->src_address);
 899   hash_mix64 (a, b, c);
 900
 901   return (u32) c;
 902 }
 903
 904 typedef struct load_balance_trace_t_
 905 {
 906     index_t lb_index;
 907 } load_balance_trace_t;
 908
 909 static uword
 910 l2_load_balance (vlib_main_t * vm,
 911                  vlib_node_runtime_t * node,
 912                  vlib_frame_t * frame)
 913 {
 914   u32 n_left_from, next_index, *from, *to_next;
 915
 916   from = vlib_frame_vector_args (frame);
 917   n_left_from = frame->n_vectors;
 918
 919   next_index = node->cached_next_index;
 920
 921   while (n_left_from > 0)
 922     {
 923       u32 n_left_to_next;
 924
 925       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 926
 927       while (n_left_from > 0 && n_left_to_next > 0)
 928         {
 929           vlib_buffer_t *b0;
 930           u32 bi0, lbi0, next0;
 931           const dpo_id_t *dpo0;
 932           const load_balance_t *lb0;
 933
 934           bi0 = from[0];
 935           to_next[0] = bi0;
 936           from += 1;
 937           to_next += 1;
 938           n_left_from -= 1;
 939           n_left_to_next -= 1;
 940
 941           b0 = vlib_get_buffer (vm, bi0);
 942
 943           /* lookup dst + src mac */
 944           lbi0 =  vnet_buffer (b0)->ip.adj_index[VLIB_TX];
 945           lb0 = load_balance_get(lbi0);
 946
 947           vnet_buffer(b0)->ip.flow_hash = l2_flow_hash(b0);
 948
 949           dpo0 = load_balance_get_bucket_i(lb0,
 950                                            vnet_buffer(b0)->ip.flow_hash &
 951                                            (lb0->lb_n_buckets_minus_1));
 952
 953           next0 = dpo0->dpoi_next_node;
 954           vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 955
 956           if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
 957             {
 958               load_balance_trace_t *tr = vlib_add_trace (vm, node, b0,
 959                                                          sizeof (*tr));
 960               tr->lb_index = lbi0;
 961             }
 962           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 963                                            n_left_to_next, bi0, next0);
 964         }
 965
 966       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 967     }
 968
 969   return frame->n_vectors;
 970 }
 971
 972 static u8 *
 973 format_load_balance_trace (u8 * s, va_list * args)
 974 {
 975   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
 976   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
 977   load_balance_trace_t *t = va_arg (*args, load_balance_trace_t *);
 978
 979   s = format (s, "L2-load-balance: index %d", t->lb_index);
 980   return s;
 981 }
 982
 983 /**
 984  * @brief
 985  */
 986 VLIB_REGISTER_NODE (l2_load_balance_node) = {
 987   .function = l2_load_balance,
 988   .name = "l2-load-balance",
 989   .vector_size = sizeof (u32),
 990
 991   .format_trace = format_load_balance_trace,
 992   .n_next_nodes = 1,
 993   .next_nodes = {
 994       [0] = "error-drop",
 995   },
 996 };