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 #include "typesafe.h"
  29
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 DECLARE_MTYPE(ROUTE_NODE);
  35
  36 /*
  37  * Forward declarations.
  38  */
  39 struct route_node;
  40 struct route_table;
  41
  42 /*
  43  * route_table_delegate_t
  44  *
  45  * Function vector that can be used by a client to customize the
  46  * behavior of one or more route tables.
  47  */
  48 typedef const struct route_table_delegate_t_ route_table_delegate_t;
  49
  50 typedef struct route_node *(*route_table_create_node_func_t)(
  51         route_table_delegate_t *, struct route_table *);
  52
  53 typedef void (*route_table_destroy_node_func_t)(route_table_delegate_t *,
  54                                                 struct route_table *,
  55                                                 struct route_node *);
  56
  57 struct route_table_delegate_t_ {
  58         route_table_create_node_func_t create_node;
  59         route_table_destroy_node_func_t destroy_node;
  60 };
  61
  62 PREDECL_HASH(rn_hash_node);
  63
  64 /* Routing table top structure. */
  65 struct route_table {
  66         struct route_node *top;
  67         struct rn_hash_node_head hash;
  68
  69         /*
  70          * Delegate that performs certain functions for this table.
  71          */
  72         route_table_delegate_t *delegate;
  73         void (*cleanup)(struct route_table *, struct route_node *);
  74
  75         unsigned long count;
  76
  77         /*
  78          * User data.
  79          */
  80         void *info;
  81 };
  82
  83 /*
  84  * node->link is really internal to the table code and should not be
  85  * accessed by outside code.  We don't have any writers (yay), though some
  86  * readers are left to be fixed.
  87  *
  88  * rationale: we need to add a hash table in parallel, to speed up
  89  * exact-match lookups.
  90  *
  91  * same really applies for node->parent, though that's less of an issue.
  92  * table->link should be - and is - NEVER written by outside code
  93  */
  94 #ifdef FRR_COMPILING_TABLE_C
  95 #define table_rdonly(x)         x
  96 #define table_internal(x)       x
  97 #else
  98 #define table_rdonly(x)         const x
  99 #define table_internal(x)                                                      \
 100         const x __attribute__(                                                 \
 101                 (deprecated("this should only be accessed by lib/table.c")))
 102 /* table_internal is for node->link and node->lock, once we have done
 103  * something about remaining accesses */
 104 #endif
 105
 106 /* so... the problem with this is that "const" doesn't mean "readonly".
 107  * It in fact may allow the compiler to optimize based on the assumption
 108  * that the value doesn't change.  Hence, since the only purpose of this
 109  * is to aid in development, don't put the "const" in release builds.
 110  *
 111  * (I haven't seen this actually break, but GCC and LLVM are getting ever
 112  * more aggressive in optimizing...)
 113  */
 114 #ifndef DEV_BUILD
 115 #undef table_rdonly
 116 #define table_rdonly(x) x
 117 #endif
 118
 119 /*
 120  * Macro that defines all fields in a route node.
 121  */
 122 #define ROUTE_NODE_FIELDS                                                      \
 123         /* Actual prefix of this radix. */                                     \
 124         struct prefix p;                                                       \
 125                                                                                \
 126         /* Tree link. */                                                       \
 127         struct route_table *table_rdonly(table);                               \
 128         struct route_node *table_rdonly(parent);                               \
 129         struct route_node *table_rdonly(link[2]);                              \
 130                                                                                \
 131         /* Lock of this radix */                                               \
 132         unsigned int table_rdonly(lock);                                       \
 133                                                                                \
 134         struct rn_hash_node_item nodehash;                                     \
 135         /* Each node of route. */                                              \
 136         void *info;                                                            \
 137
 138
 139 /* Each routing entry. */
 140 struct route_node {
 141         ROUTE_NODE_FIELDS
 142
 143 #define l_left   link[0]
 144 #define l_right  link[1]
 145 };
 146
 147 typedef struct route_table_iter_t_ route_table_iter_t;
 148
 149 typedef enum {
 150         RT_ITER_STATE_INIT,
 151         RT_ITER_STATE_ITERATING,
 152         RT_ITER_STATE_PAUSED,
 153         RT_ITER_STATE_DONE
 154 } route_table_iter_state_t;
 155
 156 /*
 157  * route_table_iter_t
 158  *
 159  * Structure that holds state for iterating over a route table.
 160  */
 161 struct route_table_iter_t_ {
 162
 163         route_table_iter_state_t state;
 164
 165         /*
 166          * Routing table that we are iterating over. The caller must ensure
 167          * that that table outlives the iterator.
 168          */
 169         struct route_table *table;
 170
 171         /*
 172          * The node that the iterator is currently on.
 173          */
 174         struct route_node *current;
 175
 176         /*
 177          * The last prefix that the iterator processed before it was paused.
 178          */
 179         struct prefix pause_prefix;
 180 };
 181
 182 /* Prototypes. */
 183 extern struct route_table *route_table_init(void);
 184
 185 extern struct route_table *
 186 route_table_init_with_delegate(route_table_delegate_t *delegate);
 187
 188 extern route_table_delegate_t *route_table_get_default_delegate(void);
 189
 190 static inline void *route_table_get_info(struct route_table *table)
 191 {
 192         return table->info;
 193 }
 194
 195 static inline void route_table_set_info(struct route_table *table, void *d)
 196 {
 197         table->info = d;
 198 }
 199
 200 extern void route_table_finish(struct route_table *table);
 201 extern struct route_node *route_top(struct route_table *table);
 202 extern struct route_node *route_next(struct route_node *node);
 203 extern struct route_node *route_next_until(struct route_node *node,
 204                                            const struct route_node *limit);
 205 extern struct route_node *route_node_get(struct route_table *table,
 206                                          union prefixconstptr pu);
 207 extern struct route_node *route_node_lookup(struct route_table *table,
 208                                             union prefixconstptr pu);
 209 extern struct route_node *route_node_lookup_maynull(struct route_table *table,
 210                                                     union prefixconstptr pu);
 211 extern struct route_node *route_node_match(struct route_table *table,
 212                                            union prefixconstptr pu);
 213 extern struct route_node *route_node_match_ipv4(struct route_table *table,
 214                                                 const struct in_addr *addr);
 215 extern struct route_node *route_node_match_ipv6(struct route_table *table,
 216                                                 const struct in6_addr *addr);
 217
 218 extern unsigned long route_table_count(struct route_table *table);
 219
 220 extern struct route_node *route_node_create(route_table_delegate_t *delegate,
 221                                             struct route_table *table);
 222 extern void route_node_delete(struct route_node *node);
 223 extern void route_node_destroy(route_table_delegate_t *delegate,
 224                                struct route_table *table,
 225                                struct route_node *node);
 226
 227 extern struct route_node *route_table_get_next(struct route_table *table,
 228                                                union prefixconstptr pu);
 229 extern int route_table_prefix_iter_cmp(const struct prefix *p1,
 230                                        const struct prefix *p2);
 231
 232 /*
 233  * Iterator functions.
 234  */
 235 extern void route_table_iter_init(route_table_iter_t *iter,
 236                                   struct route_table *table);
 237 extern void route_table_iter_pause(route_table_iter_t *iter);
 238 extern void route_table_iter_cleanup(route_table_iter_t *iter);
 239
 240 /*
 241  * Inline functions.
 242  */
 243
 244 /* Lock node. */
 245 static inline struct route_node *route_lock_node(struct route_node *node)
 246 {
 247         (*(unsigned *)&node->lock)++;
 248         return node;
 249 }
 250
 251 /* Unlock node. */
 252 static inline void route_unlock_node(struct route_node *node)
 253 {
 254         assert(node->lock > 0);
 255         (*(unsigned *)&node->lock)--;
 256
 257         if (node->lock == 0)
 258                 route_node_delete(node);
 259 }
 260
 261 static inline unsigned int route_node_get_lock_count(struct route_node *node)
 262 {
 263         return node->lock;
 264 }
 265
 266 /*
 267  * route_table_iter_next
 268  *
 269  * Get the next node in the tree.
 270  */
 271 static inline struct route_node *route_table_iter_next(route_table_iter_t *iter)
 272 {
 273         struct route_node *node;
 274
 275         switch (iter->state) {
 276
 277         case RT_ITER_STATE_INIT:
 278
 279                 /*
 280                  * We're just starting the iteration.
 281                  */
 282                 node = route_top(iter->table);
 283                 break;
 284
 285         case RT_ITER_STATE_ITERATING:
 286                 node = route_next(iter->current);
 287                 break;
 288
 289         case RT_ITER_STATE_PAUSED:
 290
 291                 /*
 292                  * Start with the node following pause_prefix.
 293                  */
 294                 node = route_table_get_next(iter->table, &iter->pause_prefix);
 295                 break;
 296
 297         case RT_ITER_STATE_DONE:
 298                 return NULL;
 299
 300         default:
 301                 /* Suppress uninitialized variable warning */
 302                 node = NULL;
 303                 assert(0);
 304         }
 305
 306         iter->current = node;
 307         if (node)
 308                 iter->state = RT_ITER_STATE_ITERATING;
 309         else
 310                 iter->state = RT_ITER_STATE_DONE;
 311
 312         return node;
 313 }
 314
 315 /*
 316  * route_table_iter_is_done
 317  *
 318  * Returns true if the iteration is complete.
 319  */
 320 static inline int route_table_iter_is_done(route_table_iter_t *iter)
 321 {
 322         return iter->state == RT_ITER_STATE_DONE;
 323 }
 324
 325 /*
 326  * route_table_iter_started
 327  *
 328  * Returns true if this iterator has started iterating over the tree.
 329  */
 330 static inline int route_table_iter_started(route_table_iter_t *iter)
 331 {
 332         return iter->state != RT_ITER_STATE_INIT;
 333 }
 334
 335 #ifdef _FRR_ATTRIBUTE_PRINTFRR
 336 #pragma FRR printfrr_ext "%pRN"  (struct route_node *)
 337 #endif
 338
 339 #ifdef __cplusplus
 340 }
 341 #endif
 342
 343 #endif /* _ZEBRA_TABLE_H */