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lib : fix duplicate prefix list delete

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Problem statement:
Step-1:
pl1 - 10.10.10.10/24 with deny sequence 1
Step-2:
pl1 - 10.10.10.10/24 with permit sequence 2
Step-3:
pl1 - 20.20.20.20/24 with deny sequence 1

Now we end up deleting permit sequence 2,
which might blackhole the traffic.

RCA:
Whenever we have multiple prefix lists,
having same prefix and different subnet range,
delete or replace of prefix list
would result in delete of entry in route-map
prefix table.

Fix:
We will skip deleting prefix list entry
from routemap prefix table, if we have
the multiple prefix lists having same prefix.

Signed-off-by: Samanvitha B Bhargav <bsamanvitha@vmware.com>
This commit is contained in:
Samanvitha B Bhargav 2023-04-24 01:51:23 -07:00
parent 25664eae52
commit 394ed767e7
1 changed files with 33 additions and 6 deletions
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39
lib/plist.c
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@ -336,6 +336,22 @@ prefix_list_entry_lookup(struct prefix_list *plist, struct prefix *prefix,
return NULL;
}
static bool
prefix_list_entry_lookup_prefix(struct prefix_list *plist,
struct prefix_list_entry *plist_entry)
{
struct prefix_list_entry *pentry = NULL;
for (pentry = plist->head; pentry; pentry = pentry->next) {
if (pentry == plist_entry)
continue;
if (prefix_same(&pentry->prefix, &plist_entry->prefix))
return true;
}
return false;
}
static void trie_walk_affected(size_t validbits, struct pltrie_table *table,
uint8_t byte, struct prefix_list_entry *object,
void (*fn)(struct prefix_list_entry *object,
@ -404,12 +420,16 @@ static void prefix_list_trie_del(struct prefix_list *plist,
void prefix_list_entry_delete(struct prefix_list *plist,
struct prefix_list_entry *pentry,
int update_list)
struct prefix_list_entry *pentry, int update_list)
{
bool duplicate = false;
if (plist == NULL || pentry == NULL)
return;
if (prefix_list_entry_lookup_prefix(plist, pentry))
duplicate = true;
prefix_list_trie_del(plist, pentry);
if (pentry->prev)
@ -421,8 +441,10 @@ void prefix_list_entry_delete(struct prefix_list *plist,
else
plist->tail = pentry->prev;
route_map_notify_pentry_dependencies(plist->name, pentry,
RMAP_EVENT_PLIST_DELETED);
if (!duplicate)
route_map_notify_pentry_dependencies(plist->name, pentry,
RMAP_EVENT_PLIST_DELETED);
prefix_list_entry_free(pentry);
plist->count--;
@ -557,11 +579,15 @@ static void prefix_list_entry_add(struct prefix_list *plist,
void prefix_list_entry_update_start(struct prefix_list_entry *ple)
{
struct prefix_list *pl = ple->pl;
bool duplicate = false;
/* Not installed, nothing to do. */
if (!ple->installed)
return;
if (prefix_list_entry_lookup_prefix(pl, ple))
duplicate = true;
prefix_list_trie_del(pl, ple);
/* List manipulation: shameless copy from `prefix_list_entry_delete`. */
@ -574,8 +600,9 @@ void prefix_list_entry_update_start(struct prefix_list_entry *ple)
else
pl->tail = ple->prev;
route_map_notify_pentry_dependencies(pl->name, ple,
RMAP_EVENT_PLIST_DELETED);
if (!duplicate)
route_map_notify_pentry_dependencies(pl->name, ple,
RMAP_EVENT_PLIST_DELETED);
pl->count--;
route_map_notify_dependencies(pl->name, RMAP_EVENT_PLIST_DELETED);