src/vnet/bier/bier_lookup.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/buffer.h>
  17 #include <vnet/vnet.h>
  18
  19 #include <vnet/bier/bier_fmask.h>
  20 #include <vnet/bier/bier_hdr_inlines.h>
  21 #include <vnet/bier/bier_table.h>
  22 #include <vnet/bier/bier_fmask.h>
  23
  24 /**
  25  * Struct maintaining the per-worker thread data for BIER lookups
  26  */
  27 typedef struct bier_lookup_main_t_
  28 {
  29     /* per-cpu vector of cloned packets */
  30     u32 **blm_clones;
  31     /* per-cpu vector of BIER fmasks */
  32     u32 **blm_fmasks;
  33 } bier_lookup_main_t;
  34
  35 /**
  36  * Single instance of the lookup main
  37  */
  38 static bier_lookup_main_t bier_lookup_main;
  39
  40 static char * bier_lookup_error_strings[] = {
  41 #define bier_error(n,s) s,
  42 #include <vnet/bier/bier_lookup_error.def>
  43 #undef bier_error
  44 };
  45
  46 /*
  47  * Keep these values semantically the same as BIER lookup
  48  */
  49 #define foreach_bier_lookup_next                \
  50     _(DROP, "bier-drop")                        \
  51     _(OUTPUT, "bier-output")
  52
  53 typedef enum {
  54 #define _(s,n) BIER_LOOKUP_NEXT_##s,
  55     foreach_bier_lookup_next
  56 #undef _
  57     BIER_LOOKUP_N_NEXT,
  58 } bier_lookup_next_t;
  59
  60 typedef enum {
  61 #define bier_error(n,s) BIER_LOOKUP_ERROR_##n,
  62 #include <vnet/bier/bier_lookup_error.def>
  63 #undef bier_error
  64     BIER_LOOKUP_N_ERROR,
  65 } bier_lookup_error_t;
  66
  67 vlib_node_registration_t bier_lookup_node;
  68
  69 /**
  70  * @brief Packet trace record for a BIER lookup
  71  */
  72 typedef struct bier_lookup_trace_t_
  73 {
  74     u32 next_index;
  75     index_t bt_index;
  76     index_t bfm_index;
  77 } bier_lookup_trace_t;
  78
  79 static uword
  80 bier_lookup (vlib_main_t * vm,
  81              vlib_node_runtime_t * node,
  82              vlib_frame_t * from_frame)
  83 {
  84     u32 n_left_from, next_index, * from, * to_next;
  85     bier_lookup_main_t *blm = &bier_lookup_main;
  86     u32 thread_index = vlib_get_thread_index();
  87     bier_bit_mask_bucket_t buckets_copy[BIER_HDR_BUCKETS_4096];
  88
  89     from = vlib_frame_vector_args (from_frame);
  90     n_left_from = from_frame->n_vectors;
  91     next_index = BIER_LOOKUP_NEXT_DROP;
  92
  93     while (n_left_from > 0)
  94     {
  95         u32 n_left_to_next;
  96
  97         vlib_get_next_frame (vm, node, next_index,
  98                              to_next, n_left_to_next);
  99
 100         while (n_left_from > 0 && n_left_to_next > 0)
 101         {
 102             u32 next0, bi0, n_bytes, bti0, bfmi0;
 103             const bier_fmask_t *bfm0;
 104             const bier_table_t *bt0;
 105             u16 index, num_buckets;
 106             const bier_hdr_t *bh0;
 107             bier_bit_string_t bbs;
 108             vlib_buffer_t *b0;
 109             bier_bp_t fbs;
 110             int bucket;
 111
 112             bi0 = from[0];
 113             from += 1;
 114             n_left_from -= 1;
 115
 116             b0 = vlib_get_buffer (vm, bi0);
 117             bh0 = vlib_buffer_get_current (b0);
 118             bti0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
 119
 120             /*
 121              * default to drop so that if no bits are matched then
 122              * that is where we go - DROP.
 123              */
 124             next0 = BIER_LOOKUP_NEXT_DROP;
 125
 126             /*
 127              * At the imposition or input node,
 128              * we stored the BIER Table index in the TX adjacency
 129              */
 130             bt0 = bier_table_get(vnet_buffer(b0)->ip.adj_index[VLIB_TX]);
 131
 132             /*
 133              * we should only forward via one for the ECMP tables
 134              */
 135             ASSERT(!bier_table_is_main(bt0));
 136
 137             /*
 138              * number of integer sized buckets
 139              */
 140             n_bytes = bier_hdr_len_id_to_num_buckets(bt0->bt_id.bti_hdr_len);
 141             vnet_buffer(b0)->mpls.bier.n_bytes = n_bytes;
 142             vnet_buffer(b0)->sw_if_index[VLIB_TX] = ~0;
 143             num_buckets = n_bytes / sizeof(int);
 144             bier_bit_string_init(&bbs,
 145                                  bt0->bt_id.bti_hdr_len,
 146                                  buckets_copy);
 147             memcpy(bbs.bbs_buckets, bh0->bh_bit_string, bbs.bbs_len);
 148
 149             /*
 150              * reset the fmask storage vector
 151              */
 152             vec_reset_length (blm->blm_fmasks[thread_index]);
 153
 154             /*
 155              * Loop through the buckets in the header
 156              */
 157             for (index = 0; index < num_buckets; index++) {
 158                 /*
 159                  * loop through each bit in the bucket
 160                  */
 161                 bucket = ((int*)bbs.bbs_buckets)[index];
 162
 163                 while (bucket) {
 164                     fbs  = bier_find_first_bit_string_set(bucket);
 165                     fbs += (((num_buckets - 1) - index) *
 166                             BIER_BIT_MASK_BITS_PER_INT);
 167
 168                     bfmi0 = bier_table_fwd_lookup(bt0, fbs);
 169
 170                     /*
 171                      * whatever happens, the bit we just looked for
 172                      * MUST be cleared from the packet
 173                      * otherwise we could be in this loop a while ...
 174                      */
 175                     bier_bit_string_clear_bit(&bbs, fbs);
 176
 177                     if (PREDICT_TRUE(INDEX_INVALID != bfmi0))
 178                     {
 179                         bfm0 = bier_fmask_get(bfmi0);
 180
 181                         /*
 182                          * use the bit-string on the fmask to reset
 183                          * the bits in the header we are walking
 184                          */
 185                         bier_bit_string_clear_string(
 186                             &bfm0->bfm_bits.bfmb_input_reset_string,
 187                             &bbs);
 188                         bucket = ((int*)bbs.bbs_buckets)[index];
 189
 190                         /*
 191                          * the fmask is resolved so replicate a
 192                          * packet its way
 193                          */
 194                         next0 = BIER_LOOKUP_NEXT_OUTPUT;
 195
 196                         vec_add1 (blm->blm_fmasks[thread_index], bfmi0);
 197                     } else {
 198                         /*
 199                          * go to the next bit-position set
 200                          */
 201                         vlib_node_increment_counter(
 202                             vm, node->node_index,
 203                             BIER_LOOKUP_ERROR_FMASK_UNRES, 1);
 204                         bucket = ((int*)bbs.bbs_buckets)[index];
 205                         continue;
 206                     }
 207                 }
 208             }
 209
 210             /*
 211              * Full mask now processed.
 212              * Create the number of clones we need based on the number
 213              * of fmasks we are sending to.
 214              */
 215             u16 num_cloned, clone;
 216             u32 n_clones;
 217
 218             n_clones = vec_len(blm->blm_fmasks[thread_index]);
 219
 220             if (PREDICT_TRUE(0 != n_clones))
 221             {
 222                 num_cloned = vlib_buffer_clone(vm, bi0,
 223                                                blm->blm_clones[thread_index],
 224                                                n_clones,
 225                                                VLIB_BUFFER_CLONE_HEAD_SIZE);
 226
 227                 vec_set_len(blm->blm_clones[thread_index], num_cloned);
 228
 229                 if (num_cloned != n_clones)
 230                 {
 231                     vlib_node_increment_counter
 232                         (vm, node->node_index,
 233                          BIER_LOOKUP_ERROR_BUFFER_ALLOCATION_FAILURE, 1);
 234                 }
 235
 236                 for (clone = 0; clone < num_cloned; clone++)
 237                 {
 238                     vlib_buffer_t *c0;
 239                     u32 ci0;
 240
 241                     ci0 = blm->blm_clones[thread_index][clone];
 242                     c0 = vlib_get_buffer(vm, ci0);
 243                     vnet_buffer(c0)->ip.adj_index[VLIB_TX] =
 244                         blm->blm_fmasks[thread_index][clone];
 245
 246                     to_next[0] = ci0;
 247                     to_next += 1;
 248                     n_left_to_next -= 1;
 249
 250                     if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
 251                     {
 252                         bier_lookup_trace_t *tr;
 253
 254                         tr = vlib_add_trace (vm, node, c0, sizeof (*tr));
 255                         tr->bt_index = bti0;
 256                         tr->bfm_index = blm->blm_fmasks[thread_index][clone];
 257                     }
 258
 259                     vlib_validate_buffer_enqueue_x1(vm, node, next_index,
 260                                                     to_next, n_left_to_next,
 261                                                     ci0, next0);
 262
 263                     /*
 264                      * After the enqueue it is possible that we over-flow the
 265                      * frame of the to-next node. When this happens we need to
 266                      * 'put' that full frame to the node and get a fresh empty
 267                      * one. Note that these are macros with side effects that
 268                      * change to_next & n_left_to_next
 269                      */
 270                     if (PREDICT_FALSE(0 == n_left_to_next))
 271                     {
 272                         vlib_put_next_frame (vm, node, next_index,
 273                                              n_left_to_next);
 274                         vlib_get_next_frame (vm, node, next_index,
 275                                              to_next, n_left_to_next);
 276                     }
 277                 }
 278             }
 279             else
 280             {
 281                 /*
 282                  * no clones/replications required. drop this packet
 283                  */
 284                 next0 = BIER_LOOKUP_NEXT_DROP;
 285                 to_next[0] = bi0;
 286                 to_next += 1;
 287                 n_left_to_next -= 1;
 288
 289                 if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
 290                 {
 291                     bier_lookup_trace_t *tr;
 292
 293                     tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
 294
 295                     tr->bt_index = bti0;
 296                     tr->bfm_index = ~0;
 297                 }
 298
 299                 vlib_validate_buffer_enqueue_x1(vm, node, next_index,
 300                                                 to_next, n_left_to_next,
 301                                                 bi0, next0);
 302             }
 303         }
 304
 305         vlib_put_next_frame(vm, node, next_index, n_left_to_next);
 306     }
 307
 308     vlib_node_increment_counter(vm, bier_lookup_node.index,
 309                                 BIER_LOOKUP_ERROR_NONE,
 310                                 from_frame->n_vectors);
 311     return (from_frame->n_vectors);
 312 }
 313
 314 static u8 *
 315 format_bier_lookup_trace (u8 * s, va_list * args)
 316 {
 317     CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
 318     CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
 319     bier_lookup_trace_t * t = va_arg (*args, bier_lookup_trace_t *);
 320
 321     s = format (s, "BIER: next [%d], tbl:%d BFM:%d",
 322                 t->next_index,
 323                 t->bt_index,
 324                 t->bfm_index);
 325     return s;
 326 }
 327
 328 VLIB_REGISTER_NODE (bier_lookup_node) = {
 329     .function = bier_lookup,
 330     .name = "bier-lookup",
 331     /* Takes a vector of packets. */
 332     .vector_size = sizeof (u32),
 333
 334     .n_errors = BIER_LOOKUP_N_ERROR,
 335     .error_strings = bier_lookup_error_strings,
 336
 337     .format_trace = format_bier_lookup_trace,
 338     .n_next_nodes = BIER_LOOKUP_N_NEXT,
 339     .next_nodes = {
 340         [BIER_LOOKUP_NEXT_DROP] = "bier-drop",
 341         [BIER_LOOKUP_NEXT_OUTPUT] = "bier-output",
 342     },
 343 };
 344
 345 clib_error_t *
 346 bier_lookup_module_init (vlib_main_t * vm)
 347 {
 348     bier_lookup_main_t *blm = &bier_lookup_main;
 349     u32 thread_index;
 350
 351     vec_validate (blm->blm_clones, vlib_num_workers());
 352     vec_validate (blm->blm_fmasks, vlib_num_workers());
 353
 354     for (thread_index = 0;
 355          thread_index <= vlib_num_workers();
 356          thread_index++)
 357     {
 358         /*
 359          *  1024 is the most we will ever need to support
 360          * a Bit-Mask length of 1024
 361          */
 362         vec_validate(blm->blm_fmasks[thread_index], 1023);
 363         vec_validate(blm->blm_clones[thread_index], 1023);
 364     }
 365
 366     return 0;
 367 }
 368
 369 VLIB_INIT_FUNCTION (bier_lookup_module_init);