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src/sonic-frr/patch/0031-lib-Fix-corruption-when-routemap-delete-add-sequence.patch
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From 5f503e5f5aecc946a168c87f3e02757deb65cbeb Mon Sep 17 00:00:00 2001 | ||
From: Donald Sharp <[email protected]> | ||
Date: Wed, 2 Mar 2022 15:41:54 -0500 | ||
Subject: [PATCH] lib: Fix corruption when routemap delete/add sequence happens | ||
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If a operator issues a series of route-map deletions and | ||
then re-adds, *and* this triggers the hash table to realloc | ||
to grow to a larger size, then subsuquent route-map operations | ||
will be against a corrupted hash table. | ||
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Why? | ||
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Effectively the route-map code was inserting each | ||
route-map <NAME> into a hash for storage. Upon | ||
deletion there is this concept of delayed processing | ||
so the routemap code sets a bit `to-be-processed` | ||
and marks the route-map for deletion. This is | ||
1 entry in the hash table. Then if the operator | ||
recreates the hash, FRR would add another hash | ||
entry. If another deletion happens then there | ||
now are 2 deletion entries that are indistinguishable | ||
from a hash perspective. | ||
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FRR stores the deleted name of the route-map so that | ||
any delayed processing can lookup the name and only process | ||
those peers that are related to that route-map name. | ||
This is good as that if in say BGP, we do not want | ||
to reprocess all the peers that don't use the route-map. | ||
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Solution: | ||
The whole purpose of the delay of deletion and the | ||
storage of the route-map is to allow the using protocol | ||
the ability to process the route-map at a later time | ||
while still retaining the route-map name( for more efficient | ||
reprocessing ). The problem exists because we are keeping | ||
multiple copies of deletion events that are indistinguishable | ||
from each other causing hash havoc. | ||
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The truth is that we only need to keep 1 copy of the | ||
routemap in the table. If the series of events is: | ||
a) delete ( schedule processing ) | ||
b) add ( reschedule processing ) | ||
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Current code ends up processing the route-map two times | ||
and in this event we really just need to reprocess everything | ||
with the new route-map. | ||
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If the series of events is: | ||
a) delete (schedule processing ) | ||
b) add (reschedule) | ||
c) delete (reschedule) | ||
d) add (reschedule) | ||
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All this really points to is that FRR just needs to keep the last | ||
in the series of maps and ensuring that FRR knows that we need | ||
to continue processing the route-map. So in the creation processing | ||
if the hash has an entry for this map, the routemap code knows that | ||
this is a deletion event. Mark this route-map for later processing | ||
if it was marked so. Also in the lookup function do not return | ||
a map if the map found was deleted. | ||
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Fixes: #10708 | ||
Signed-off-by: Donald Sharp <[email protected]> | ||
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--- | ||
lib/routemap.c | 25 ++++++++++++++----------- | ||
1 file changed, 14 insertions(+), 11 deletions(-) | ||
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diff --git a/lib/routemap.c b/lib/routemap.c | ||
index 7f733c811..8f343ccd9 100644 | ||
--- a/lib/routemap.c | ||
+++ b/lib/routemap.c | ||
@@ -101,6 +101,7 @@ static void route_map_del_plist_entries(afi_t afi, | ||
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static struct hash *route_map_get_dep_hash(route_map_event_t event); | ||
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+static void route_map_free_map(struct route_map *map); | ||
struct route_map_match_set_hooks rmap_match_set_hook; | ||
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/* match interface */ | ||
@@ -566,15 +567,8 @@ static bool route_map_hash_cmp(const void *p1, const void *p2) | ||
const struct route_map *map1 = p1; | ||
const struct route_map *map2 = p2; | ||
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- if (map1->deleted == map2->deleted) { | ||
- if (map1->name && map2->name) { | ||
- if (!strcmp(map1->name, map2->name)) { | ||
- return true; | ||
- } | ||
- } else if (!map1->name && !map2->name) { | ||
- return true; | ||
- } | ||
- } | ||
+ if (!strcmp(map1->name, map2->name)) | ||
+ return true; | ||
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return false; | ||
} | ||
@@ -636,13 +630,18 @@ static struct route_map *route_map_new(const char *name) | ||
/* Add new name to route_map. */ | ||
static struct route_map *route_map_add(const char *name) | ||
{ | ||
- struct route_map *map; | ||
+ struct route_map *map, *exist; | ||
struct route_map_list *list; | ||
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map = route_map_new(name); | ||
list = &route_map_master; | ||
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/* Add map to the hash */ | ||
+ exist = hash_release(route_map_master_hash, map); | ||
+ if (exist) { | ||
+ map->to_be_processed = exist->to_be_processed; | ||
+ route_map_free_map(exist); | ||
+ } | ||
hash_get(route_map_master_hash, map, hash_alloc_intern); | ||
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/* Add new entry to the head of the list to match how it is added in the | ||
@@ -752,11 +751,15 @@ struct route_map *route_map_lookup_by_name(const char *name) | ||
if (!name) | ||
return NULL; | ||
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- // map.deleted is 0 via memset | ||
+ // map.deleted is false via memset | ||
memset(&tmp_map, 0, sizeof(struct route_map)); | ||
tmp_map.name = XSTRDUP(MTYPE_ROUTE_MAP_NAME, name); | ||
map = hash_lookup(route_map_master_hash, &tmp_map); | ||
XFREE(MTYPE_ROUTE_MAP_NAME, tmp_map.name); | ||
+ | ||
+ if (map && map->deleted) | ||
+ return NULL; | ||
+ | ||
return map; | ||
} | ||
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