From: Maria Matejka <mq@ucw.cz>
Date: Thu, 13 Feb 2025 11:12:20 +0000 (+0100)
Subject: Taming static checker: Do not request bits on negative positions in prefixes
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d7682d2e49dccb659ada682c9eead3e85cf7e576;p=thirdparty%2Fbird.git

Taming static checker: Do not request bits on negative positions in prefixes

The code is actually called. It's harmless, yet confusing.
---

diff --git a/filter/trie.c b/filter/trie.c
index 12ba0b82b..4edd6f2ec 100644
--- a/filter/trie.c
+++ b/filter/trie.c
@@ -641,7 +641,7 @@ trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr
       if (len > pxlen)
 	goto done;
 
-      if (ip4_getbit(n->accept, len - 1))
+      if ((len > 0) && ip4_getbit(n->accept, len - 1))
       {
 	/* len is always < 32 due to len < n->plen */
 	ip4_setbit(&found, len);
@@ -735,7 +735,7 @@ trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr
       if (len > pxlen)
 	goto done;
 
-      if (ip6_getbit(n->accept, len - 1))
+      if ((len > 0) && ip6_getbit(n->accept, len - 1))
       {
 	/* len is always < 128 due to len < n->plen */
 	ip6_setbit(&found, len);