2 * Routing Table functions.
3 * Copyright (C) 1998 Kunihiro Ishiguro
5 * This file is part of GNU Zebra.
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
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.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Zebra; see the file COPYING. If not, write to the Free
19 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
28 #include "sockunion.h"
30 DEFINE_MTYPE( LIB
, ROUTE_TABLE
, "Route table")
31 DEFINE_MTYPE( LIB
, ROUTE_NODE
, "Route node")
33 static void route_node_delete (struct route_node
*);
34 static void route_table_free (struct route_table
*);
38 * route_table_init_with_delegate
41 route_table_init_with_delegate (route_table_delegate_t
*delegate
)
43 struct route_table
*rt
;
45 rt
= XCALLOC (MTYPE_ROUTE_TABLE
, sizeof (struct route_table
));
46 rt
->delegate
= delegate
;
51 route_table_finish (struct route_table
*rt
)
53 route_table_free (rt
);
56 /* Allocate new route node. */
57 static struct route_node
*
58 route_node_new (struct route_table
*table
)
60 return table
->delegate
->create_node (table
->delegate
, table
);
63 /* Allocate new route node with prefix set. */
64 static struct route_node
*
65 route_node_set (struct route_table
*table
, const struct prefix
*prefix
)
67 struct route_node
*node
;
69 node
= route_node_new (table
);
71 prefix_copy (&node
->p
, prefix
);
77 /* Free route node. */
79 route_node_free (struct route_table
*table
, struct route_node
*node
)
82 table
->cleanup(table
, node
);
83 table
->delegate
->destroy_node (table
->delegate
, table
, node
);
86 /* Free route table. */
88 route_table_free (struct route_table
*rt
)
90 struct route_node
*tmp_node
;
91 struct route_node
*node
;
98 /* Bulk deletion of nodes remaining in this table. This function is not
99 called until workers have completed their dependency on this table.
100 A final route_unlock_node() will not be called for these nodes. */
111 node
= node
->l_right
;
118 tmp_node
->table
->count
--;
119 tmp_node
->lock
= 0; /* to cause assert if unlocked after this */
120 route_node_free (rt
, tmp_node
);
124 if (node
->l_left
== tmp_node
)
127 node
->l_right
= NULL
;
135 assert (rt
->count
== 0);
137 XFREE (MTYPE_ROUTE_TABLE
, rt
);
141 /* Utility mask array. */
142 static const u_char maskbit
[] =
144 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff
147 /* Common prefix route genaration. */
149 route_common (const struct prefix
*n
, const struct prefix
*p
, struct prefix
*new)
155 const u_char
*np
= (const u_char
*)&n
->u
.prefix
;
156 const u_char
*pp
= (const u_char
*)&p
->u
.prefix
;
157 u_char
*newp
= (u_char
*)&new->u
.prefix
;
159 for (i
= 0; i
< p
->prefixlen
/ 8; i
++)
167 new->prefixlen
= i
* 8;
169 if (new->prefixlen
!= p
->prefixlen
)
171 diff
= np
[i
] ^ pp
[i
];
173 while (new->prefixlen
< p
->prefixlen
&& !(mask
& diff
))
178 newp
[i
] = np
[i
] & maskbit
[new->prefixlen
% 8];
183 set_link (struct route_node
*node
, struct route_node
*new)
185 unsigned int bit
= prefix_bit (&new->p
.u
.prefix
, node
->p
.prefixlen
);
187 node
->link
[bit
] = new;
193 route_lock_node (struct route_node
*node
)
201 route_unlock_node (struct route_node
*node
)
203 assert (node
->lock
> 0);
207 route_node_delete (node
);
210 /* Find matched prefix. */
212 route_node_match (const struct route_table
*table
, const struct prefix
*p
)
214 struct route_node
*node
;
215 struct route_node
*matched
;
220 /* Walk down tree. If there is matched route then store it to
222 while (node
&& node
->p
.prefixlen
<= p
->prefixlen
&&
223 prefix_match (&node
->p
, p
))
228 if (node
->p
.prefixlen
== p
->prefixlen
)
231 node
= node
->link
[prefix_bit(&p
->u
.prefix
, node
->p
.prefixlen
)];
234 /* If matched route found, return it. */
236 return route_lock_node (matched
);
242 route_node_match_ipv4 (const struct route_table
*table
,
243 const struct in_addr
*addr
)
245 struct prefix_ipv4 p
;
247 memset (&p
, 0, sizeof (struct prefix_ipv4
));
249 p
.prefixlen
= IPV4_MAX_PREFIXLEN
;
252 return route_node_match (table
, (struct prefix
*) &p
);
256 route_node_match_ipv6 (const struct route_table
*table
,
257 const struct in6_addr
*addr
)
259 struct prefix_ipv6 p
;
261 memset (&p
, 0, sizeof (struct prefix_ipv6
));
263 p
.prefixlen
= IPV6_MAX_PREFIXLEN
;
266 return route_node_match (table
, (struct prefix
*) &p
);
269 /* Lookup same prefix node. Return NULL when we can't find route. */
271 route_node_lookup (const struct route_table
*table
, const struct prefix
*p
)
273 struct route_node
*node
;
274 u_char prefixlen
= p
->prefixlen
;
275 const u_char
*prefix
= &p
->u
.prefix
;
279 while (node
&& node
->p
.prefixlen
<= prefixlen
&&
280 prefix_match (&node
->p
, p
))
282 if (node
->p
.prefixlen
== prefixlen
)
283 return node
->info
? route_lock_node (node
) : NULL
;
285 node
= node
->link
[prefix_bit(prefix
, node
->p
.prefixlen
)];
291 /* Lookup same prefix node. Return NULL when we can't find route. */
293 route_node_lookup_maynull (const struct route_table
*table
, const struct prefix
*p
)
295 struct route_node
*node
;
296 u_char prefixlen
= p
->prefixlen
;
297 const u_char
*prefix
= &p
->u
.prefix
;
301 while (node
&& node
->p
.prefixlen
<= prefixlen
&&
302 prefix_match (&node
->p
, p
))
304 if (node
->p
.prefixlen
== prefixlen
)
305 return route_lock_node (node
);
307 node
= node
->link
[prefix_bit(prefix
, node
->p
.prefixlen
)];
313 /* Add node to routing table. */
315 route_node_get (struct route_table
*const table
, const struct prefix
*p
)
317 struct route_node
*new;
318 struct route_node
*node
;
319 struct route_node
*match
;
320 u_char prefixlen
= p
->prefixlen
;
321 const u_char
*prefix
= &p
->u
.prefix
;
325 while (node
&& node
->p
.prefixlen
<= prefixlen
&&
326 prefix_match (&node
->p
, p
))
328 if (node
->p
.prefixlen
== prefixlen
)
329 return route_lock_node (node
);
332 node
= node
->link
[prefix_bit(prefix
, node
->p
.prefixlen
)];
337 new = route_node_set (table
, p
);
339 set_link (match
, new);
345 new = route_node_new (table
);
346 route_common (&node
->p
, p
, &new->p
);
347 new->p
.family
= p
->family
;
349 set_link (new, node
);
352 set_link (match
, new);
356 if (new->p
.prefixlen
!= p
->prefixlen
)
359 new = route_node_set (table
, p
);
360 set_link (match
, new);
365 route_lock_node (new);
370 /* Delete node from the routing table. */
372 route_node_delete (struct route_node
*node
)
374 struct route_node
*child
;
375 struct route_node
*parent
;
377 assert (node
->lock
== 0);
378 assert (node
->info
== NULL
);
380 if (node
->l_left
&& node
->l_right
)
384 child
= node
->l_left
;
386 child
= node
->l_right
;
388 parent
= node
->parent
;
391 child
->parent
= parent
;
395 if (parent
->l_left
== node
)
396 parent
->l_left
= child
;
398 parent
->l_right
= child
;
401 node
->table
->top
= child
;
403 node
->table
->count
--;
405 /* WARNING: FRAGILE CODE!
406 * route_node_free may have the side effect of free'ing the entire table.
407 * this is permitted only if table->count got decremented to zero above,
408 * because in that case parent will also be NULL, so that we won't try to
409 * delete a now-stale parent below.
411 * cf. srcdest_srcnode_destroy() in zebra/zebra_rib.c */
413 route_node_free (node
->table
, node
);
415 /* If parent node is stub then delete it also. */
416 if (parent
&& parent
->lock
== 0)
417 route_node_delete (parent
);
420 /* Get fist node and lock it. This function is useful when one want
421 to lookup all the node exist in the routing table. */
423 route_top (struct route_table
*table
)
425 /* If there is no node in the routing table return NULL. */
426 if (table
->top
== NULL
)
429 /* Lock the top node and return it. */
430 route_lock_node (table
->top
);
434 /* Unlock current node and lock next node then return it. */
436 route_next (struct route_node
*node
)
438 struct route_node
*next
;
439 struct route_node
*start
;
441 /* Node may be deleted from route_unlock_node so we have to preserve
442 next node's pointer. */
447 route_lock_node (next
);
448 route_unlock_node (node
);
453 next
= node
->l_right
;
454 route_lock_node (next
);
455 route_unlock_node (node
);
462 if (node
->parent
->l_left
== node
&& node
->parent
->l_right
)
464 next
= node
->parent
->l_right
;
465 route_lock_node (next
);
466 route_unlock_node (start
);
471 route_unlock_node (start
);
475 /* Unlock current node and lock next node until limit. */
477 route_next_until (struct route_node
*node
, struct route_node
*limit
)
479 struct route_node
*next
;
480 struct route_node
*start
;
482 /* Node may be deleted from route_unlock_node so we have to preserve
483 next node's pointer. */
488 route_lock_node (next
);
489 route_unlock_node (node
);
494 next
= node
->l_right
;
495 route_lock_node (next
);
496 route_unlock_node (node
);
501 while (node
->parent
&& node
!= limit
)
503 if (node
->parent
->l_left
== node
&& node
->parent
->l_right
)
505 next
= node
->parent
->l_right
;
506 route_lock_node (next
);
507 route_unlock_node (start
);
512 route_unlock_node (start
);
517 route_table_count (const struct route_table
*table
)
525 * Default function for creating a route node.
528 route_node_create (route_table_delegate_t
*delegate
,
529 struct route_table
*table
)
531 struct route_node
*node
;
532 node
= XCALLOC (MTYPE_ROUTE_NODE
, sizeof (struct route_node
));
539 * Default function for destroying a route node.
542 route_node_destroy (route_table_delegate_t
*delegate
,
543 struct route_table
*table
, struct route_node
*node
)
545 XFREE (MTYPE_ROUTE_NODE
, node
);
551 static route_table_delegate_t default_delegate
= {
552 .create_node
= route_node_create
,
553 .destroy_node
= route_node_destroy
556 route_table_delegate_t
*
557 route_table_get_default_delegate(void)
559 return &default_delegate
;
566 route_table_init (void)
568 return route_table_init_with_delegate (&default_delegate
);
572 * route_table_prefix_iter_cmp
574 * Compare two prefixes according to the order in which they appear in
575 * an iteration over a tree.
577 * @return -1 if p1 occurs before p2 (p1 < p2)
578 * 0 if the prefixes are identical (p1 == p2)
579 * +1 if p1 occurs after p2 (p1 > p2)
582 route_table_prefix_iter_cmp (struct prefix
*p1
, struct prefix
*p2
)
584 struct prefix common_space
;
585 struct prefix
*common
= &common_space
;
587 if (p1
->prefixlen
<= p2
->prefixlen
)
589 if (prefix_match (p1
, p2
))
593 * p1 contains p2, or is equal to it.
595 return (p1
->prefixlen
== p2
->prefixlen
) ? 0 : -1;
602 * Check if p2 contains p1.
604 if (prefix_match (p2
, p1
))
608 route_common (p1
, p2
, common
);
609 assert (common
->prefixlen
< p1
->prefixlen
);
610 assert (common
->prefixlen
< p2
->prefixlen
);
613 * Both prefixes are longer than the common prefix.
615 * We need to check the bit after the common prefixlen to determine
616 * which one comes later.
618 if (prefix_bit (&p1
->u
.prefix
, common
->prefixlen
))
622 * We branch to the right to get to p1 from the common prefix.
624 assert (!prefix_bit (&p2
->u
.prefix
, common
->prefixlen
));
629 * We branch to the right to get to p2 from the common prefix.
631 assert (prefix_bit (&p2
->u
.prefix
, common
->prefixlen
));
636 * route_get_subtree_next
638 * Helper function that returns the first node that follows the nodes
639 * in the sub-tree under 'node' in iteration order.
641 static struct route_node
*
642 route_get_subtree_next (struct route_node
*node
)
646 if (node
->parent
->l_left
== node
&& node
->parent
->l_right
)
647 return node
->parent
->l_right
;
656 * route_table_get_next_internal
658 * Helper function to find the node that occurs after the given prefix in
659 * order of iteration.
661 * @see route_table_get_next
663 static struct route_node
*
664 route_table_get_next_internal (const struct route_table
*table
,
667 struct route_node
*node
, *tmp_node
;
676 if (node
->p
.prefixlen
< p
->prefixlen
)
677 match
= prefix_match (&node
->p
, p
);
679 match
= prefix_match (p
, &node
->p
);
683 if (node
->p
.prefixlen
== p
->prefixlen
)
687 * The prefix p exists in the tree, just return the next
690 route_lock_node (node
);
691 node
= route_next (node
);
693 route_unlock_node (node
);
698 if (node
->p
.prefixlen
> p
->prefixlen
)
702 * Node is in the subtree of p, and hence greater than p.
708 * p is in the sub-tree under node.
710 tmp_node
= node
->link
[prefix_bit (&p
->u
.prefix
, node
->p
.prefixlen
)];
719 * There are no nodes in the direction where p should be. If
720 * node has a right child, then it must be greater than p.
723 return node
->l_right
;
726 * No more children to follow, go upwards looking for the next
729 return route_get_subtree_next (node
);
733 * Neither node prefix nor 'p' contains the other.
735 cmp
= route_table_prefix_iter_cmp (&node
->p
, p
);
740 * Node follows p in iteration order. Return it.
748 * Node and the subtree under it come before prefix p in
749 * iteration order. Prefix p and its sub-tree are not present in
750 * the tree. Go upwards and find the first node that follows the
751 * subtree. That node will also succeed p.
753 return route_get_subtree_next (node
);
760 * route_table_get_next
762 * Find the node that occurs after the given prefix in order of
766 route_table_get_next (const struct route_table
*table
, struct prefix
*p
)
768 struct route_node
*node
;
770 node
= route_table_get_next_internal (table
, p
);
773 assert (route_table_prefix_iter_cmp (&node
->p
, p
) > 0);
774 route_lock_node (node
);
780 * route_table_iter_init
783 route_table_iter_init (route_table_iter_t
* iter
, struct route_table
*table
)
785 memset (iter
, 0, sizeof (*iter
));
786 iter
->state
= RT_ITER_STATE_INIT
;
791 * route_table_iter_pause
793 * Pause an iteration over the table. This allows the iteration to be
794 * resumed point after arbitrary additions/deletions from the table.
795 * An iteration can be resumed by just calling route_table_iter_next()
799 route_table_iter_pause (route_table_iter_t
* iter
)
804 case RT_ITER_STATE_INIT
:
805 case RT_ITER_STATE_PAUSED
:
806 case RT_ITER_STATE_DONE
:
809 case RT_ITER_STATE_ITERATING
:
812 * Save the prefix that we are currently at. The next call to
813 * route_table_iter_next() will return the node after this prefix
816 prefix_copy (&iter
->pause_prefix
, &iter
->current
->p
);
817 route_unlock_node (iter
->current
);
818 iter
->current
= NULL
;
819 iter
->state
= RT_ITER_STATE_PAUSED
;
829 * route_table_iter_cleanup
831 * Release any resources held by the iterator.
834 route_table_iter_cleanup (route_table_iter_t
* iter
)
836 if (iter
->state
== RT_ITER_STATE_ITERATING
)
838 route_unlock_node (iter
->current
);
839 iter
->current
= NULL
;
841 assert (!iter
->current
);
844 * Set the state to RT_ITER_STATE_DONE to make any
845 * route_table_iter_next() calls on this iterator return NULL.
847 iter
->state
= RT_ITER_STATE_DONE
;