[PATCH 1/1] cache: fix AVL tree traversal in cache_record_find() and cache_host_is_known()

[mroeder at metz-connect.com]

From: Martin Röder <mroeder at metz-connect.com>

The AVL tree traversal in both functions systematically misses the last
AVL tree element. This can lead to duplicate cache entries and lookup failures.

The fix duplicates the correct AVL tree traversal approach of cache_dump_recursive().

Signed-off-by: Martin Röder <mroeder at metz-connect.com>
---
 cache.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/cache.c b/cache.c
index ea6a4c8..d1816df 100644
--- a/cache.c
+++ b/cache.c
@@ -191,13 +191,10 @@ cache_record_find(char *record, int type, int port, int rdlength, uint8_t *rdata
 {
 	struct cache_record *l = avl_find_element(&records, record, l, avl);
 
-	if (!l)
-		return NULL;
-
-	while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
+	while (l && !strcmp(l->record, record)) {
 		struct cache_record *r = l;
 
-		l = avl_next_element(l, avl);
+		l = !avl_is_last(&records, &l->avl) ? avl_next_element(l, avl) : NULL;
 		if (r->type != type)
 			continue;
 
@@ -227,13 +224,10 @@ cache_host_is_known(char *record)
 {
 	struct cache_record *l = avl_find_element(&records, record, l, avl);
 
-	if (!l)
-		return 0;
-
-	while (l && !avl_is_last(&records, &l->avl) && !strcmp(l->record, record)) {
+	while (l && !strcmp(l->record, record)) {
 		struct cache_record *r = l;
 
-		l = avl_next_element(l, avl);
+		l = !avl_is_last(&records, &l->avl) ? avl_next_element(l, avl) : NULL;
 		if ((r->type != TYPE_A) && (r->type != TYPE_AAAA))
 			continue;
 		return 1;
-- 
2.20.1