lib/table.h

   1 /*
   2  * Routing Table
   3  * Copyright (C) 1998 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef _ZEBRA_TABLE_H
  23 #define _ZEBRA_TABLE_H
  24
  25 #include "memory.h"
  26 #include "hash.h"
  27 #include "prefix.h"
  28 DECLARE_MTYPE(ROUTE_TABLE)
  29 DECLARE_MTYPE(ROUTE_NODE)
  30
  31 /*
  32  * Forward declarations.
  33  */
  34 struct route_node;
  35 struct route_table;
  36
  37 /*
  38  * route_table_delegate_t
  39  *
  40  * Function vector that can be used by a client to customize the
  41  * behavior of one or more route tables.
  42  */
  43 typedef struct route_table_delegate_t_ route_table_delegate_t;
  44
  45 typedef struct route_node *(*route_table_create_node_func_t)(
  46         route_table_delegate_t *, struct route_table *);
  47
  48 typedef void (*route_table_destroy_node_func_t)(route_table_delegate_t *,
  49                                                 struct route_table *,
  50                                                 struct route_node *);
  51
  52 struct route_table_delegate_t_ {
  53         route_table_create_node_func_t create_node;
  54         route_table_destroy_node_func_t destroy_node;
  55 };
  56
  57 /* Routing table top structure. */
  58 struct route_table {
  59         struct route_node *top;
  60         struct hash *hash;
  61
  62         /*
  63          * Delegate that performs certain functions for this table.
  64          */
  65         route_table_delegate_t *delegate;
  66         void (*cleanup)(struct route_table *, struct route_node *);
  67
  68         unsigned long count;
  69
  70         /*
  71          * User data.
  72          */
  73         void *info;
  74 };
  75
  76 /*
  77  * node->link is really internal to the table code and should not be
  78  * accessed by outside code.  We don't have any writers (yay), though some
  79  * readers are left to be fixed.
  80  *
  81  * rationale: we need to add a hash table in parallel, to speed up
  82  * exact-match lookups.
  83  *
  84  * same really applies for node->parent, though that's less of an issue.
  85  * table->link should be - and is - NEVER written by outside code
  86  */
  87 #ifdef FRR_COMPILING_TABLE_C
  88 #define table_rdonly(x)         x
  89 #define table_internal(x)       x
  90 #else
  91 #define table_rdonly(x)         const x
  92 #define table_internal(x)                                                      \
  93         const x __attribute__(                                                 \
  94                 (deprecated("this should only be accessed by lib/table.c")))
  95 /* table_internal is for node->link and node->lock, once we have done
  96  * something about remaining accesses */
  97 #endif
  98
  99 /* so... the problem with this is that "const" doesn't mean "readonly".
 100  * It in fact may allow the compiler to optimize based on the assumption
 101  * that the value doesn't change.  Hence, since the only purpose of this
 102  * is to aid in development, don't put the "const" in release builds.
 103  *
 104  * (I haven't seen this actually break, but GCC and LLVM are getting ever
 105  * more aggressive in optimizing...)
 106  */
 107 #ifndef DEV_BUILD
 108 #undef table_rdonly
 109 #define table_rdonly(x) x
 110 #endif
 111
 112 /*
 113  * Macro that defines all fields in a route node.
 114  */
 115 #define ROUTE_NODE_FIELDS                                                      \
 116         /* Actual prefix of this radix. */                                     \
 117         struct prefix p;                                                       \
 118                                                                                \
 119         /* Tree link. */                                                       \
 120         struct route_table *table_rdonly(table);                               \
 121         struct route_node *table_rdonly(parent);                               \
 122         struct route_node *table_rdonly(link[2]);                              \
 123                                                                                \
 124         /* Lock of this radix */                                               \
 125         unsigned int table_rdonly(lock);                                       \
 126                                                                                \
 127         /* Each node of route. */                                              \
 128         void *info;                                                            \
 129                                                                                \
 130         /* Aggregation. */                                                     \
 131         void *aggregate;
 132
 133
 134 /* Each routing entry. */
 135 struct route_node {
 136         ROUTE_NODE_FIELDS
 137
 138 #define l_left   link[0]
 139 #define l_right  link[1]
 140 };
 141
 142 typedef struct route_table_iter_t_ route_table_iter_t;
 143
 144 typedef enum {
 145         RT_ITER_STATE_INIT,
 146         RT_ITER_STATE_ITERATING,
 147         RT_ITER_STATE_PAUSED,
 148         RT_ITER_STATE_DONE
 149 } route_table_iter_state_t;
 150
 151 /*
 152  * route_table_iter_t
 153  *
 154  * Structure that holds state for iterating over a route table.
 155  */
 156 struct route_table_iter_t_ {
 157
 158         route_table_iter_state_t state;
 159
 160         /*
 161          * Routing table that we are iterating over. The caller must ensure
 162          * that that table outlives the iterator.
 163          */
 164         struct route_table *table;
 165
 166         /*
 167          * The node that the iterator is currently on.
 168          */
 169         struct route_node *current;
 170
 171         /*
 172          * The last prefix that the iterator processed before it was paused.
 173          */
 174         struct prefix pause_prefix;
 175 };
 176
 177 /* Prototypes. */
 178 extern struct route_table *route_table_init(void);
 179
 180 extern struct route_table *
 181 route_table_init_with_delegate(route_table_delegate_t *delegate);
 182
 183 extern route_table_delegate_t *route_table_get_default_delegate(void);
 184
 185 extern void route_table_finish(struct route_table *table);
 186 extern struct route_node *route_top(struct route_table *table);
 187 extern struct route_node *route_next(struct route_node *node);
 188 extern struct route_node *route_next_until(struct route_node *node,
 189                                            const struct route_node *limit);
 190 extern struct route_node *route_node_get(struct route_table *const table,
 191                                          union prefixconstptr pu);
 192 extern struct route_node *route_node_lookup(const struct route_table *table,
 193                                             union prefixconstptr pu);
 194 extern struct route_node *
 195 route_node_lookup_maynull(const struct route_table *table,
 196                           union prefixconstptr pu);
 197 extern struct route_node *route_node_match(const struct route_table *table,
 198                                            union prefixconstptr pu);
 199 extern struct route_node *route_node_match_ipv4(const struct route_table *table,
 200                                                 const struct in_addr *addr);
 201 extern struct route_node *route_node_match_ipv6(const struct route_table *table,
 202                                                 const struct in6_addr *addr);
 203
 204 extern unsigned long route_table_count(const struct route_table *table);
 205
 206 extern struct route_node *route_node_create(route_table_delegate_t *delegate,
 207                                             struct route_table *table);
 208 extern void route_node_delete(struct route_node *node);
 209 extern void route_node_destroy(route_table_delegate_t *delegate,
 210                                struct route_table *table,
 211                                struct route_node *node);
 212
 213 extern struct route_node *route_table_get_next(const struct route_table *table,
 214                                                union prefixconstptr pu);
 215 extern int route_table_prefix_iter_cmp(const struct prefix *p1,
 216                                        const struct prefix *p2);
 217
 218 /*
 219  * Iterator functions.
 220  */
 221 extern void route_table_iter_init(route_table_iter_t *iter,
 222                                   struct route_table *table);
 223 extern void route_table_iter_pause(route_table_iter_t *iter);
 224 extern void route_table_iter_cleanup(route_table_iter_t *iter);
 225
 226 /*
 227  * Inline functions.
 228  */
 229
 230 /* Lock node. */
 231 static inline struct route_node *route_lock_node(struct route_node *node)
 232 {
 233         (*(unsigned *)&node->lock)++;
 234         return node;
 235 }
 236
 237 /* Unlock node. */
 238 static inline void route_unlock_node(struct route_node *node)
 239 {
 240         assert(node->lock > 0);
 241         (*(unsigned *)&node->lock)--;
 242
 243         if (node->lock == 0)
 244                 route_node_delete(node);
 245 }
 246
 247 /*
 248  * route_table_iter_next
 249  *
 250  * Get the next node in the tree.
 251  */
 252 static inline struct route_node *route_table_iter_next(route_table_iter_t *iter)
 253 {
 254         struct route_node *node;
 255
 256         switch (iter->state) {
 257
 258         case RT_ITER_STATE_INIT:
 259
 260                 /*
 261                  * We're just starting the iteration.
 262                  */
 263                 node = route_top(iter->table);
 264                 break;
 265
 266         case RT_ITER_STATE_ITERATING:
 267                 node = route_next(iter->current);
 268                 break;
 269
 270         case RT_ITER_STATE_PAUSED:
 271
 272                 /*
 273                  * Start with the node following pause_prefix.
 274                  */
 275                 node = route_table_get_next(iter->table, &iter->pause_prefix);
 276                 break;
 277
 278         case RT_ITER_STATE_DONE:
 279                 return NULL;
 280
 281         default:
 282                 assert(0);
 283         }
 284
 285         iter->current = node;
 286         if (node)
 287                 iter->state = RT_ITER_STATE_ITERATING;
 288         else
 289                 iter->state = RT_ITER_STATE_DONE;
 290
 291         return node;
 292 }
 293
 294 /*
 295  * route_table_iter_is_done
 296  *
 297  * Returns TRUE if the iteration is complete.
 298  */
 299 static inline int route_table_iter_is_done(route_table_iter_t *iter)
 300 {
 301         return iter->state == RT_ITER_STATE_DONE;
 302 }
 303
 304 /*
 305  * route_table_iter_started
 306  *
 307  * Returns TRUE if this iterator has started iterating over the tree.
 308  */
 309 static inline int route_table_iter_started(route_table_iter_t *iter)
 310 {
 311         return iter->state != RT_ITER_STATE_INIT;
 312 }
 313
 314 #endif /* _ZEBRA_TABLE_H */