src/vnet/ip/ip4_forward.h

   1 /*
   2  * Copyright (c) 2015 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  * ip/ip4_forward.h: IP v4 forwarding
  17  *
  18  * Copyright (c) 2008 Eliot Dresselhaus
  19  *
  20  * Permission is hereby granted, free of charge, to any person obtaining
  21  * a copy of this software and associated documentation files (the
  22  * "Software"), to deal in the Software without restriction, including
  23  * without limitation the rights to use, copy, modify, merge, publish,
  24  * distribute, sublicense, and/or sell copies of the Software, and to
  25  * permit persons to whom the Software is furnished to do so, subject to
  26  * the following conditions:
  27  *
  28  * The above copyright notice and this permission notice shall be
  29  * included in all copies or substantial portions of the Software.
  30  *
  31  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  32  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  33  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  34  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  35  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  36  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  37  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  38  */
  39
  40 #ifndef __included_ip4_forward_h__
  41 #define __included_ip4_forward_h__
  42
  43 #include <vppinfra/cache.h>
  44 #include <vnet/fib/ip4_fib.h>
  45 #include <vnet/dpo/load_balance_map.h>
  46
  47 /**
  48  * @file
  49  * @brief IPv4 Forwarding.
  50  *
  51  * This file contains the source code for IPv4 forwarding.
  52  */
  53
  54 always_inline uword
  55 ip4_lookup_inline (vlib_main_t * vm,
  56                    vlib_node_runtime_t * node,
  57                    vlib_frame_t * frame,
  58                    int lookup_for_responses_to_locally_received_packets)
  59 {
  60   ip4_main_t *im = &ip4_main;
  61   vlib_combined_counter_main_t *cm = &load_balance_main.lbm_to_counters;
  62   u32 n_left_from, n_left_to_next, *from, *to_next;
  63   ip_lookup_next_t next;
  64   u32 thread_index = vm->thread_index;
  65   vlib_buffer_t *bufs[VLIB_FRAME_SIZE];
  66   vlib_buffer_t **b = bufs;
  67
  68   from = vlib_frame_vector_args (frame);
  69   n_left_from = frame->n_vectors;
  70   next = node->cached_next_index;
  71   vlib_get_buffers (vm, from, bufs, n_left_from);
  72
  73   while (n_left_from > 0)
  74     {
  75       vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
  76
  77 #if (CLIB_N_PREFETCHES >= 8)
  78       while (n_left_from >= 8 && n_left_to_next >= 4)
  79         {
  80           vlib_buffer_t *p0, *p1, *p2, *p3;
  81           ip4_header_t *ip0, *ip1, *ip2, *ip3;
  82           ip_lookup_next_t next0, next1, next2, next3;
  83           const load_balance_t *lb0, *lb1, *lb2, *lb3;
  84           ip4_fib_mtrie_t *mtrie0, *mtrie1, *mtrie2, *mtrie3;
  85           ip4_fib_mtrie_leaf_t leaf0, leaf1, leaf2, leaf3;
  86           ip4_address_t *dst_addr0, *dst_addr1, *dst_addr2, *dst_addr3;
  87           u32 pi0, pi1, pi2, pi3, lb_index0, lb_index1, lb_index2, lb_index3;
  88           flow_hash_config_t flow_hash_config0, flow_hash_config1;
  89           flow_hash_config_t flow_hash_config2, flow_hash_config3;
  90           u32 hash_c0, hash_c1, hash_c2, hash_c3;
  91           const dpo_id_t *dpo0, *dpo1, *dpo2, *dpo3;
  92
  93           /* Prefetch next iteration. */
  94           {
  95             vlib_prefetch_buffer_header (b[4], LOAD);
  96             vlib_prefetch_buffer_header (b[5], LOAD);
  97             vlib_prefetch_buffer_header (b[6], LOAD);
  98             vlib_prefetch_buffer_header (b[7], LOAD);
  99
 100             CLIB_PREFETCH (b[4]->data, sizeof (ip0[0]), LOAD);
 101             CLIB_PREFETCH (b[5]->data, sizeof (ip0[0]), LOAD);
 102             CLIB_PREFETCH (b[6]->data, sizeof (ip0[0]), LOAD);
 103             CLIB_PREFETCH (b[7]->data, sizeof (ip0[0]), LOAD);
 104           }
 105
 106           pi0 = to_next[0] = from[0];
 107           pi1 = to_next[1] = from[1];
 108           pi2 = to_next[2] = from[2];
 109           pi3 = to_next[3] = from[3];
 110
 111           from += 4;
 112           to_next += 4;
 113           n_left_to_next -= 4;
 114           n_left_from -= 4;
 115
 116           p0 = b[0];
 117           p1 = b[1];
 118           p2 = b[2];
 119           p3 = b[3];
 120           b += 4;
 121
 122           ip0 = vlib_buffer_get_current (p0);
 123           ip1 = vlib_buffer_get_current (p1);
 124           ip2 = vlib_buffer_get_current (p2);
 125           ip3 = vlib_buffer_get_current (p3);
 126
 127           dst_addr0 = &ip0->dst_address;
 128           dst_addr1 = &ip1->dst_address;
 129           dst_addr2 = &ip2->dst_address;
 130           dst_addr3 = &ip3->dst_address;
 131
 132           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p0);
 133           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p1);
 134           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p2);
 135           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p3);
 136
 137           if (!lookup_for_responses_to_locally_received_packets)
 138             {
 139               mtrie0 = &ip4_fib_get (vnet_buffer (p0)->ip.fib_index)->mtrie;
 140               mtrie1 = &ip4_fib_get (vnet_buffer (p1)->ip.fib_index)->mtrie;
 141               mtrie2 = &ip4_fib_get (vnet_buffer (p2)->ip.fib_index)->mtrie;
 142               mtrie3 = &ip4_fib_get (vnet_buffer (p3)->ip.fib_index)->mtrie;
 143
 144               leaf0 = ip4_fib_mtrie_lookup_step_one (mtrie0, dst_addr0);
 145               leaf1 = ip4_fib_mtrie_lookup_step_one (mtrie1, dst_addr1);
 146               leaf2 = ip4_fib_mtrie_lookup_step_one (mtrie2, dst_addr2);
 147               leaf3 = ip4_fib_mtrie_lookup_step_one (mtrie3, dst_addr3);
 148             }
 149
 150           if (!lookup_for_responses_to_locally_received_packets)
 151             {
 152               leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 2);
 153               leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 2);
 154               leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 2);
 155               leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 2);
 156             }
 157
 158           if (!lookup_for_responses_to_locally_received_packets)
 159             {
 160               leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 3);
 161               leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 3);
 162               leaf2 = ip4_fib_mtrie_lookup_step (mtrie2, leaf2, dst_addr2, 3);
 163               leaf3 = ip4_fib_mtrie_lookup_step (mtrie3, leaf3, dst_addr3, 3);
 164             }
 165
 166           if (lookup_for_responses_to_locally_received_packets)
 167             {
 168               lb_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_RX];
 169               lb_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_RX];
 170               lb_index2 = vnet_buffer (p2)->ip.adj_index[VLIB_RX];
 171               lb_index3 = vnet_buffer (p3)->ip.adj_index[VLIB_RX];
 172             }
 173           else
 174             {
 175               lb_index0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
 176               lb_index1 = ip4_fib_mtrie_leaf_get_adj_index (leaf1);
 177               lb_index2 = ip4_fib_mtrie_leaf_get_adj_index (leaf2);
 178               lb_index3 = ip4_fib_mtrie_leaf_get_adj_index (leaf3);
 179             }
 180
 181           ASSERT (lb_index0 && lb_index1 && lb_index2 && lb_index3);
 182           lb0 = load_balance_get (lb_index0);
 183           lb1 = load_balance_get (lb_index1);
 184           lb2 = load_balance_get (lb_index2);
 185           lb3 = load_balance_get (lb_index3);
 186
 187           ASSERT (lb0->lb_n_buckets > 0);
 188           ASSERT (is_pow2 (lb0->lb_n_buckets));
 189           ASSERT (lb1->lb_n_buckets > 0);
 190           ASSERT (is_pow2 (lb1->lb_n_buckets));
 191           ASSERT (lb2->lb_n_buckets > 0);
 192           ASSERT (is_pow2 (lb2->lb_n_buckets));
 193           ASSERT (lb3->lb_n_buckets > 0);
 194           ASSERT (is_pow2 (lb3->lb_n_buckets));
 195
 196           /* Use flow hash to compute multipath adjacency. */
 197           hash_c0 = vnet_buffer (p0)->ip.flow_hash = 0;
 198           hash_c1 = vnet_buffer (p1)->ip.flow_hash = 0;
 199           hash_c2 = vnet_buffer (p2)->ip.flow_hash = 0;
 200           hash_c3 = vnet_buffer (p3)->ip.flow_hash = 0;
 201           if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
 202             {
 203               flow_hash_config0 = lb0->lb_hash_config;
 204               hash_c0 = vnet_buffer (p0)->ip.flow_hash =
 205                 ip4_compute_flow_hash (ip0, flow_hash_config0);
 206               dpo0 =
 207                 load_balance_get_fwd_bucket (lb0,
 208                                              (hash_c0 &
 209                                               (lb0->lb_n_buckets_minus_1)));
 210             }
 211           else
 212             {
 213               dpo0 = load_balance_get_bucket_i (lb0, 0);
 214             }
 215           if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
 216             {
 217               flow_hash_config1 = lb1->lb_hash_config;
 218               hash_c1 = vnet_buffer (p1)->ip.flow_hash =
 219                 ip4_compute_flow_hash (ip1, flow_hash_config1);
 220               dpo1 =
 221                 load_balance_get_fwd_bucket (lb1,
 222                                              (hash_c1 &
 223                                               (lb1->lb_n_buckets_minus_1)));
 224             }
 225           else
 226             {
 227               dpo1 = load_balance_get_bucket_i (lb1, 0);
 228             }
 229           if (PREDICT_FALSE (lb2->lb_n_buckets > 1))
 230             {
 231               flow_hash_config2 = lb2->lb_hash_config;
 232               hash_c2 = vnet_buffer (p2)->ip.flow_hash =
 233                 ip4_compute_flow_hash (ip2, flow_hash_config2);
 234               dpo2 =
 235                 load_balance_get_fwd_bucket (lb2,
 236                                              (hash_c2 &
 237                                               (lb2->lb_n_buckets_minus_1)));
 238             }
 239           else
 240             {
 241               dpo2 = load_balance_get_bucket_i (lb2, 0);
 242             }
 243           if (PREDICT_FALSE (lb3->lb_n_buckets > 1))
 244             {
 245               flow_hash_config3 = lb3->lb_hash_config;
 246               hash_c3 = vnet_buffer (p3)->ip.flow_hash =
 247                 ip4_compute_flow_hash (ip3, flow_hash_config3);
 248               dpo3 =
 249                 load_balance_get_fwd_bucket (lb3,
 250                                              (hash_c3 &
 251                                               (lb3->lb_n_buckets_minus_1)));
 252             }
 253           else
 254             {
 255               dpo3 = load_balance_get_bucket_i (lb3, 0);
 256             }
 257
 258           next0 = dpo0->dpoi_next_node;
 259           vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 260           next1 = dpo1->dpoi_next_node;
 261           vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
 262           next2 = dpo2->dpoi_next_node;
 263           vnet_buffer (p2)->ip.adj_index[VLIB_TX] = dpo2->dpoi_index;
 264           next3 = dpo3->dpoi_next_node;
 265           vnet_buffer (p3)->ip.adj_index[VLIB_TX] = dpo3->dpoi_index;
 266
 267           vlib_increment_combined_counter
 268             (cm, thread_index, lb_index0, 1,
 269              vlib_buffer_length_in_chain (vm, p0));
 270           vlib_increment_combined_counter
 271             (cm, thread_index, lb_index1, 1,
 272              vlib_buffer_length_in_chain (vm, p1));
 273           vlib_increment_combined_counter
 274             (cm, thread_index, lb_index2, 1,
 275              vlib_buffer_length_in_chain (vm, p2));
 276           vlib_increment_combined_counter
 277             (cm, thread_index, lb_index3, 1,
 278              vlib_buffer_length_in_chain (vm, p3));
 279
 280           vlib_validate_buffer_enqueue_x4 (vm, node, next,
 281                                            to_next, n_left_to_next,
 282                                            pi0, pi1, pi2, pi3,
 283                                            next0, next1, next2, next3);
 284         }
 285 #elif (CLIB_N_PREFETCHES >= 4)
 286       while (n_left_from >= 4 && n_left_to_next >= 2)
 287         {
 288           vlib_buffer_t *p0, *p1;
 289           ip4_header_t *ip0, *ip1;
 290           ip_lookup_next_t next0, next1;
 291           const load_balance_t *lb0, *lb1;
 292           ip4_fib_mtrie_t *mtrie0, *mtrie1;
 293           ip4_fib_mtrie_leaf_t leaf0, leaf1;
 294           ip4_address_t *dst_addr0, *dst_addr1;
 295           u32 pi0, pi1, lb_index0, lb_index1;
 296           flow_hash_config_t flow_hash_config0, flow_hash_config1;
 297           u32 hash_c0, hash_c1;
 298           const dpo_id_t *dpo0, *dpo1;
 299
 300           /* Prefetch next iteration. */
 301           {
 302             vlib_prefetch_buffer_header (b[2], LOAD);
 303             vlib_prefetch_buffer_header (b[3], LOAD);
 304
 305             CLIB_PREFETCH (b[2]->data, sizeof (ip0[0]), LOAD);
 306             CLIB_PREFETCH (b[3]->data, sizeof (ip0[0]), LOAD);
 307           }
 308
 309           pi0 = to_next[0] = from[0];
 310           pi1 = to_next[1] = from[1];
 311
 312           from += 2;
 313           to_next += 2;
 314           n_left_to_next -= 2;
 315           n_left_from -= 2;
 316
 317           p0 = b[0];
 318           p1 = b[1];
 319           b += 2;
 320
 321           ip0 = vlib_buffer_get_current (p0);
 322           ip1 = vlib_buffer_get_current (p1);
 323
 324           dst_addr0 = &ip0->dst_address;
 325           dst_addr1 = &ip1->dst_address;
 326
 327           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p0);
 328           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p1);
 329
 330           if (!lookup_for_responses_to_locally_received_packets)
 331             {
 332               mtrie0 = &ip4_fib_get (vnet_buffer (p0)->ip.fib_index)->mtrie;
 333               mtrie1 = &ip4_fib_get (vnet_buffer (p1)->ip.fib_index)->mtrie;
 334
 335               leaf0 = ip4_fib_mtrie_lookup_step_one (mtrie0, dst_addr0);
 336               leaf1 = ip4_fib_mtrie_lookup_step_one (mtrie1, dst_addr1);
 337             }
 338
 339           if (!lookup_for_responses_to_locally_received_packets)
 340             {
 341               leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 2);
 342               leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 2);
 343             }
 344
 345           if (!lookup_for_responses_to_locally_received_packets)
 346             {
 347               leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 3);
 348               leaf1 = ip4_fib_mtrie_lookup_step (mtrie1, leaf1, dst_addr1, 3);
 349             }
 350
 351           if (lookup_for_responses_to_locally_received_packets)
 352             {
 353               lb_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_RX];
 354               lb_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_RX];
 355             }
 356           else
 357             {
 358               lb_index0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
 359               lb_index1 = ip4_fib_mtrie_leaf_get_adj_index (leaf1);
 360             }
 361
 362           ASSERT (lb_index0 && lb_index1);
 363           lb0 = load_balance_get (lb_index0);
 364           lb1 = load_balance_get (lb_index1);
 365
 366           ASSERT (lb0->lb_n_buckets > 0);
 367           ASSERT (is_pow2 (lb0->lb_n_buckets));
 368           ASSERT (lb1->lb_n_buckets > 0);
 369           ASSERT (is_pow2 (lb1->lb_n_buckets));
 370
 371           /* Use flow hash to compute multipath adjacency. */
 372           hash_c0 = vnet_buffer (p0)->ip.flow_hash = 0;
 373           hash_c1 = vnet_buffer (p1)->ip.flow_hash = 0;
 374           if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
 375             {
 376               flow_hash_config0 = lb0->lb_hash_config;
 377               hash_c0 = vnet_buffer (p0)->ip.flow_hash =
 378                 ip4_compute_flow_hash (ip0, flow_hash_config0);
 379               dpo0 =
 380                 load_balance_get_fwd_bucket (lb0,
 381                                              (hash_c0 &
 382                                               (lb0->lb_n_buckets_minus_1)));
 383             }
 384           else
 385             {
 386               dpo0 = load_balance_get_bucket_i (lb0, 0);
 387             }
 388           if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
 389             {
 390               flow_hash_config1 = lb1->lb_hash_config;
 391               hash_c1 = vnet_buffer (p1)->ip.flow_hash =
 392                 ip4_compute_flow_hash (ip1, flow_hash_config1);
 393               dpo1 =
 394                 load_balance_get_fwd_bucket (lb1,
 395                                              (hash_c1 &
 396                                               (lb1->lb_n_buckets_minus_1)));
 397             }
 398           else
 399             {
 400               dpo1 = load_balance_get_bucket_i (lb1, 0);
 401             }
 402
 403           next0 = dpo0->dpoi_next_node;
 404           vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 405           next1 = dpo1->dpoi_next_node;
 406           vnet_buffer (p1)->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
 407
 408           vlib_increment_combined_counter
 409             (cm, thread_index, lb_index0, 1,
 410              vlib_buffer_length_in_chain (vm, p0));
 411           vlib_increment_combined_counter
 412             (cm, thread_index, lb_index1, 1,
 413              vlib_buffer_length_in_chain (vm, p1));
 414
 415           vlib_validate_buffer_enqueue_x2 (vm, node, next,
 416                                            to_next, n_left_to_next,
 417                                            pi0, pi1, next0, next1);
 418         }
 419 #endif
 420       while (n_left_from > 0 && n_left_to_next > 0)
 421         {
 422           vlib_buffer_t *p0;
 423           ip4_header_t *ip0;
 424           ip_lookup_next_t next0;
 425           const load_balance_t *lb0;
 426           ip4_fib_mtrie_t *mtrie0;
 427           ip4_fib_mtrie_leaf_t leaf0;
 428           ip4_address_t *dst_addr0;
 429           u32 pi0, lbi0;
 430           flow_hash_config_t flow_hash_config0;
 431           const dpo_id_t *dpo0;
 432           u32 hash_c0;
 433
 434           pi0 = from[0];
 435           to_next[0] = pi0;
 436
 437           p0 = b[0];
 438           b += 1;
 439
 440           ip0 = vlib_buffer_get_current (p0);
 441           dst_addr0 = &ip0->dst_address;
 442           ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, p0);
 443
 444           if (!lookup_for_responses_to_locally_received_packets)
 445             {
 446               mtrie0 = &ip4_fib_get (vnet_buffer (p0)->ip.fib_index)->mtrie;
 447               leaf0 = ip4_fib_mtrie_lookup_step_one (mtrie0, dst_addr0);
 448             }
 449
 450           if (!lookup_for_responses_to_locally_received_packets)
 451             leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 2);
 452
 453           if (!lookup_for_responses_to_locally_received_packets)
 454             leaf0 = ip4_fib_mtrie_lookup_step (mtrie0, leaf0, dst_addr0, 3);
 455
 456           if (lookup_for_responses_to_locally_received_packets)
 457             lbi0 = vnet_buffer (p0)->ip.adj_index[VLIB_RX];
 458           else
 459             {
 460               /* Handle default route. */
 461               lbi0 = ip4_fib_mtrie_leaf_get_adj_index (leaf0);
 462             }
 463
 464           ASSERT (lbi0);
 465           lb0 = load_balance_get (lbi0);
 466
 467           ASSERT (lb0->lb_n_buckets > 0);
 468           ASSERT (is_pow2 (lb0->lb_n_buckets));
 469
 470           /* Use flow hash to compute multipath adjacency. */
 471           hash_c0 = vnet_buffer (p0)->ip.flow_hash = 0;
 472           if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
 473             {
 474               flow_hash_config0 = lb0->lb_hash_config;
 475
 476               hash_c0 = vnet_buffer (p0)->ip.flow_hash =
 477                 ip4_compute_flow_hash (ip0, flow_hash_config0);
 478               dpo0 =
 479                 load_balance_get_fwd_bucket (lb0,
 480                                              (hash_c0 &
 481                                               (lb0->lb_n_buckets_minus_1)));
 482             }
 483           else
 484             {
 485               dpo0 = load_balance_get_bucket_i (lb0, 0);
 486             }
 487
 488           next0 = dpo0->dpoi_next_node;
 489           vnet_buffer (p0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
 490
 491           vlib_increment_combined_counter (cm, thread_index, lbi0, 1,
 492                                            vlib_buffer_length_in_chain (vm,
 493                                                                         p0));
 494
 495           from += 1;
 496           to_next += 1;
 497           n_left_to_next -= 1;
 498           n_left_from -= 1;
 499
 500           if (PREDICT_FALSE (next0 != next))
 501             {
 502               n_left_to_next += 1;
 503               vlib_put_next_frame (vm, node, next, n_left_to_next);
 504               next = next0;
 505               vlib_get_next_frame (vm, node, next, to_next, n_left_to_next);
 506               to_next[0] = pi0;
 507               to_next += 1;
 508               n_left_to_next -= 1;
 509             }
 510         }
 511
 512       vlib_put_next_frame (vm, node, next, n_left_to_next);
 513     }
 514
 515   if (node->flags & VLIB_NODE_FLAG_TRACE)
 516     ip4_forward_next_trace (vm, node, frame, VLIB_TX);
 517
 518   return frame->n_vectors;
 519 }
 520
 521 #endif /* __included_ip4_forward_h__ */
 522
 523 /*
 524  * fd.io coding-style-patch-verification: ON
 525  *
 526  * Local Variables:
 527  * eval: (c-set-style "gnu")
 528  * End:
 529  */