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lib,zebra: Fix ALL_NEXTHOPS iterator

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Signed-off-by: Christian Franke <chris@opensourcerouting.org>
This commit is contained in:
Christian Franke 2017-07-12 18:27:55 +02:00
parent 7215c4f058
commit 9fb47c0584
3 changed files with 43 additions and 33 deletions
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31
lib/nexthop.c
View File

@ -242,3 +242,34 @@ nexthop2str (struct nexthop *nexthop, char *str, int size)
return str;
}
/*
* Iteration step for ALL_NEXTHOPS macro:
* This is the tricky part. Check if `nexthop' has
* NEXTHOP_FLAG_RECURSIVE set. If yes, this implies that `nexthop' has
* at least one nexthop attached to `nexthop->resolved', which will be
* the next one.
*
* If NEXTHOP_FLAG_RECURSIVE is not set, `nexthop' will progress in its
* current chain. In case its current chain end is reached, it will move
* upwards in the recursion levels and progress there. Whenever a step
* forward in a chain is done, recursion will be checked again.
* In a nustshell, it's equivalent to a pre-traversal order assuming that
* left branch is 'resolved' and right branch is 'next':
* https://en.wikipedia.org/wiki/Tree_traversal#/media/File:Sorted_binary_tree_preorder.svg
*/
struct nexthop *
nexthop_next(struct nexthop *nexthop)
{
if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
return nexthop->resolved;
if (nexthop->next)
return nexthop->next;
for (struct nexthop *par = nexthop->rparent; par; par = par->rparent)
if (par->next)
return par->next;
return NULL;
}

12
lib/nexthop.h
View File

@ -93,6 +93,17 @@ struct nexthop
struct nexthop_label *nh_label;
};
/* The following for loop allows to iterate over the nexthop
* structure of routes.
*
* head: The pointer to the first nexthop in the chain.
*
* nexthop: The pointer to the current nexthop, either in the
* top-level chain or in a resolved chain.
*/
#define ALL_NEXTHOPS(head, nexthop) \
(nexthop) = (head); (nexthop); (nexthop) = nexthop_next(nexthop)
extern int zebra_rnh_ip_default_route;
extern int zebra_rnh_ipv6_default_route;
@ -121,4 +132,5 @@ extern int nexthop_same_no_recurse (struct nexthop *next1, struct nexthop *next2
extern int nexthop_labels_match (struct nexthop *nh1, struct nexthop *nh2);
extern const char * nexthop2str (struct nexthop *nexthop, char *str, int size);
extern struct nexthop *nexthop_next(struct nexthop *nexthop);
#endif /*_LIB_NEXTHOP_H */

33
zebra/rib.h
View File

@ -178,39 +178,6 @@ typedef struct rib_dest_t_
#define RNODE_FOREACH_RE_SAFE(rn, re, next) \
RE_DEST_FOREACH_ROUTE_SAFE (rib_dest_from_rnode (rn), re, next)
/* The following for loop allows to iterate over the nexthop
* structure of routes.
*
* head: The pointer to the first nexthop in the chain.
*
* nexthop: The pointer to the current nexthop, either in the
* top-level chain or in a resolved chain.
*
* Initialization: Set `nexthop' to the head of the top-level chain.
*
* Iteration check: Check that the `nexthop' pointer is not NULL.
*
* Iteration step: This is the tricky part. Check if `nexthop' has
* NEXTHOP_FLAG_RECURSIVE set. If yes, this implies that `nexthop' has
* at least one nexthop attached to `nexthop->resolved', which will be
* the next one.
*
* If NEXTHOP_FLAG_RECURSIVE is not set, `nexthop' will progress in its
* current chain. In case its current chain end is reached, it will try
* to get up to the previous recursion level and progress there. Whenever
* a step forward in a chain is done, recursion will be checked again.
* In a nustshell, it's equivalent to a pre-traversal order assuming that
* left branch is 'resolved' and right branch is 'next':
* https://en.wikipedia.org/wiki/Tree_traversal#/media/File:Sorted_binary_tree_preorder.svg
*/
#define ALL_NEXTHOPS(head, nexthop) \
(nexthop) = (head); \
(nexthop); \
(nexthop) = CHECK_FLAG((nexthop)->flags, NEXTHOP_FLAG_RECURSIVE) \
? ((nexthop)->resolved) \
: ((nexthop)->next ? (nexthop)->next \
: ((nexthop)->rparent ? (nexthop)->rparent->next : NULL))
#if defined (HAVE_RTADV)
/* Structure which hold status of router advertisement. */
struct rtadv