keytag generation (avahi_keytag()) and a few more constants for RRSIG generation.

git-svn-id: file:///home/lennart/svn/public/avahi/branches/federico2@1732 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 15 insertions, 1 deletions

diff --git a/avahi-core/domain-util.c b/avahi-core/domain-util.c
index 0d6ba14..7f562db 100644
--- a/avahi-core/domain-util.c
+++ b/avahi-core/domain-util.c
@@ -237,4 +237,18 @@ uint8_t avahi_count_canonical_labels(const char* input){
     }
 
     return count;
-}
\ No newline at end of file
+}
+
+/* reference keytag generator from RFC 4034 */
+/* invoke with avahi_keytag(<rdata>, <rdlength>); */
+uint16_t avahi_keytag(uint8_t key[], uint16_t keysize){
+    uint32_t ac;
+    int i;
+
+    for (ac = 0, i = 0; i < keysize; ++i)
+        ac += (i & 1) ? key[i] : key[i] << 8;
+
+    ac += (ac >> 16) & 0xFFFF;
+
+    return ac & 0xFFFF;
+   }