dnsserver_common: comments about record sorting

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/source4/dns_server/dnsserver_common.c b/source4/dns_server/dnsserver_common.c
index 02f958b3c082779978d796960c1acfb31480bc9e..30c1db6bee9d2ecdf774862071195d000ff79ed8 100644 (file)
--- a/source4/dns_server/dnsserver_common.c
+++ b/source4/dns_server/dnsserver_common.c
@@ -637,13 +637,16 @@ static int rec_cmp(const struct dnsp_DnssrvRpcRecord *r1,
 {
        if (r1->wType != r2->wType) {
                /*
-                * The records are sorted with higher types first
+                * The records are sorted with higher types first,
+                * which puts tombstones (type 0) last.
                 */
                return r2->wType - r1->wType;
        }
-
        /*
-        * Then we need to sort from the oldest to newest timestamp
+        * Then we need to sort from the oldest to newest timestamp.
+        *
+        * Note that dwTimeStamp == 0 (never expiring) records come first,
+        * then the ones whose expiry is soonest.
         */
        return r1->dwTimeStamp - r2->dwTimeStamp;
 }