src/vnet/fib/ip4_fib_hash.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/fib/fib_table.h>
  17 #include <vnet/fib/fib_entry.h>
  18 #include <vnet/fib/ip4_fib.h>
  19
  20 /*
  21  * ip4_fib_hash_table_lookup_exact_match
  22  *
  23  * Exact match prefix lookup
  24  */
  25 fib_node_index_t
  26 ip4_fib_hash_table_lookup_exact_match (const ip4_fib_hash_t *fib,
  27                                        const ip4_address_t *addr,
  28                                        u32 len)
  29 {
  30     uword * hash, * result;
  31     u32 key;
  32
  33     hash = fib->fib_entry_by_dst_address[len];
  34     key  = (addr->data_u32 & ip4_main.fib_masks[len]);
  35
  36     result = hash_get(hash, key);
  37
  38     if (NULL != result) {
  39         return (result[0]);
  40     }
  41     return (FIB_NODE_INDEX_INVALID);
  42 }
  43
  44 /*
  45  * ip4_fib_hash_table_lookup_adj
  46  *
  47  * Longest prefix match
  48  */
  49 index_t
  50 ip4_fib_hash_table_lookup_lb (const ip4_fib_hash_t *fib,
  51                               const ip4_address_t *addr)
  52 {
  53     fib_node_index_t fei;
  54
  55     fei = ip4_fib_hash_table_lookup(fib, addr, 32);
  56
  57     if (FIB_NODE_INDEX_INVALID != fei)
  58     {
  59         const dpo_id_t *dpo;
  60
  61         dpo = fib_entry_contribute_ip_forwarding(fei);
  62
  63         return (dpo->dpoi_index);
  64     }
  65     return (INDEX_INVALID);
  66 }
  67
  68 /*
  69  * ip4_fib_hash_table_lookup
  70  *
  71  * Longest prefix match
  72  */
  73 fib_node_index_t
  74 ip4_fib_hash_table_lookup (const ip4_fib_hash_t *fib,
  75                            const ip4_address_t *addr,
  76                            u32 len)
  77 {
  78     uword * hash, * result;
  79     i32 mask_len;
  80     u32 key;
  81
  82     for (mask_len = len; mask_len >= 0; mask_len--)
  83     {
  84         hash = fib->fib_entry_by_dst_address[mask_len];
  85         key = (addr->data_u32 & ip4_main.fib_masks[mask_len]);
  86
  87         result = hash_get (hash, key);
  88
  89         if (NULL != result) {
  90             return (result[0]);
  91         }
  92     }
  93     return (FIB_NODE_INDEX_INVALID);
  94 }
  95
  96 void
  97 ip4_fib_hash_table_entry_insert (ip4_fib_hash_t *fib,
  98                                  const ip4_address_t *addr,
  99                                  u32 len,
 100                                  fib_node_index_t fib_entry_index)
 101 {
 102     uword * hash, * result;
 103     u32 key;
 104
 105     key = (addr->data_u32 & ip4_main.fib_masks[len]);
 106     hash = fib->fib_entry_by_dst_address[len];
 107     result = hash_get (hash, key);
 108
 109     if (NULL == result) {
 110         /*
 111          * adding a new entry
 112          */
 113
 114         if (NULL == hash) {
 115             hash = hash_create (32 /* elts */, sizeof (uword));
 116             hash_set_flags (hash, HASH_FLAG_NO_AUTO_SHRINK);
 117
 118         }
 119         hash = hash_set(hash, key, fib_entry_index);
 120         fib->fib_entry_by_dst_address[len] = hash;
 121     }
 122     else
 123     {
 124         ASSERT(0);
 125     }
 126 }
 127
 128 void
 129 ip4_fib_hash_table_entry_remove (ip4_fib_hash_t *fib,
 130                                  const ip4_address_t *addr,
 131                                  u32 len)
 132 {
 133     uword * hash, * result;
 134     u32 key;
 135
 136     key = (addr->data_u32 & ip4_main.fib_masks[len]);
 137     hash = fib->fib_entry_by_dst_address[len];
 138     result = hash_get (hash, key);
 139
 140     if (NULL == result)
 141     {
 142         /*
 143          * removing a non-existent entry. i'll allow it.
 144          */
 145     }
 146     else
 147     {
 148         hash_unset(hash, key);
 149     }
 150
 151     fib->fib_entry_by_dst_address[len] = hash;
 152 }
 153
 154 void
 155 ip4_fib_hash_table_walk (ip4_fib_hash_t *fib,
 156                          fib_table_walk_fn_t fn,
 157                          void *ctx)
 158 {
 159     fib_prefix_t root = {
 160         .fp_proto = FIB_PROTOCOL_IP4,
 161         // address and length default to all 0
 162     };
 163
 164     /*
 165      * A full tree walk is the dengenerate case of a sub-tree from
 166      * the very root
 167      */
 168     return (ip4_fib_hash_table_sub_tree_walk(fib, &root, fn, ctx));
 169 }
 170
 171 void
 172 ip4_fib_hash_table_sub_tree_walk (ip4_fib_hash_t *fib,
 173                                   const fib_prefix_t *root,
 174                                   fib_table_walk_fn_t fn,
 175                                   void *ctx)
 176 {
 177     fib_prefix_t *sub_trees = NULL;
 178     int i;
 179
 180     /*
 181      * There is no efficient way to walk this array of hash tables.
 182      * so we walk each table with a mask length greater than and equal to
 183      * the required root and check it is covered by the root.
 184      */
 185     for (i = root->fp_len;
 186          i < ARRAY_LEN (fib->fib_entry_by_dst_address);
 187          i++)
 188     {
 189         uword * hash = fib->fib_entry_by_dst_address[i];
 190
 191         if (NULL != hash)
 192         {
 193             ip4_address_t key;
 194             hash_pair_t * p;
 195
 196             hash_foreach_pair (p, hash,
 197             ({
 198                 key.as_u32 = p->key;
 199                 if (ip4_destination_matches_route(&ip4_main,
 200                                                   &key,
 201                                                   &root->fp_addr.ip4,
 202                                                   root->fp_len))
 203                 {
 204                     const fib_prefix_t *sub_tree;
 205                     int skip = 0;
 206
 207                     /*
 208                      * exclude sub-trees the walk does not want to explore
 209                      */
 210                     vec_foreach(sub_tree, sub_trees)
 211                     {
 212                         if (ip4_destination_matches_route(&ip4_main,
 213                                                           &key,
 214                                                           &sub_tree->fp_addr.ip4,
 215                                                           sub_tree->fp_len))
 216                         {
 217                             skip = 1;
 218                             break;
 219                         }
 220                     }
 221
 222                     if (!skip)
 223                     {
 224                         switch (fn(p->value[0], ctx))
 225                         {
 226                         case FIB_TABLE_WALK_CONTINUE:
 227                             break;
 228                         case FIB_TABLE_WALK_SUB_TREE_STOP: {
 229                             fib_prefix_t pfx = {
 230                                 .fp_proto = FIB_PROTOCOL_IP4,
 231                                 .fp_len = i,
 232                                 .fp_addr.ip4 = key,
 233                             };
 234                             vec_add1(sub_trees, pfx);
 235                             break;
 236                         }
 237                         case FIB_TABLE_WALK_STOP:
 238                             goto done;
 239                         }
 240                     }
 241                 }
 242             }));
 243         }
 244     }
 245 done:
 246     vec_free(sub_trees);
 247     return;
 248 }
 249