[PATCH] Bugfix for OpenWrt package umdns

[MRoeder at metz-connect.com]

Hi John,

I would like to submit a patch for the OpenWrt package umdns. The patch 
fixes a bug in the cache.c functions cache_record_find() and 
cache_host_is_known(). In both functions, the last element of the AVL tree 
is systematically missed, which can lead to duplicate cache entries and 
lookup failures. The fix duplicates the correct AVL tree traversal 
approach of cache_dump_recursive().

PS: Appologies if this message has format issues. This is my first attempt 
to submit a patch to OpenWrt through our company IBM Notes infrastructure, 
please let me know if the message format is unsuitable.

Best regards,
  Martin

--------------------------------
Fix AVL tree traversal in cache_record_find() and cache_host_is_known():

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>

--- a/cache.c
+++ b/cache.c
@@ -191,13 +191,10 @@ cache_record_find(char *record, int type
 {
        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;