dnsserver/common: Use cached dnsHostName to reduce database reads

The code to clobber the host name appears to have caused DNS requests to use 3x as much resources

Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Thu Jun 22 13:06:07 CEST 2017 on sn-devel-144

diff --git a/source4/dns_server/dnsserver_common.c b/source4/dns_server/dnsserver_common.c
index d0c0a2fdbb4f407308f990a564d241b0639f1357..a56ff08031ba77a1a0929c8f5bad5b6a8959dddd 100644 (file)
--- a/source4/dns_server/dnsserver_common.c
+++ b/source4/dns_server/dnsserver_common.c
@@ -89,11 +89,9 @@ WERROR dns_common_extract(struct ldb_context *samdb,
        for (ri = 0; ri < el->num_values; ri++) {
                bool am_rodc;
                int ret;
-               const char *attrs[] = { "dnsHostName", NULL };
-               const char *dnsHostName;
+               const char *dnsHostName = NULL;
                struct ldb_val *v = &el->values[ri];
                enum ndr_err_code ndr_err;
-               struct ldb_result *res = NULL;
                ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
                                (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
                if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
@@ -121,27 +119,13 @@ WERROR dns_common_extract(struct ldb_context *samdb,
                        continue;
                }
 
-               ret = dsdb_search_dn(samdb, mem_ctx, &res, NULL,
-                                    attrs, 0);
-
-               if (res->count != 1 || ret != LDB_SUCCESS) {
-                       DEBUG(0, ("Failed to get rootDSE for dnsHostName: %s",
-                                 ldb_errstring(samdb)));
-                       return DNS_ERR(SERVER_FAILURE);
-               }
-
-               dnsHostName
-                       = ldb_msg_find_attr_as_string(res->msgs[0],
-                                                     "dnsHostName",
-                                                     NULL);
-
-               if (dnsHostName == NULL) {
+               ret = samdb_dns_host_name(samdb, &dnsHostName);
+               if (ret != LDB_SUCCESS || dnsHostName == NULL) {
                        DEBUG(0, ("Failed to get dnsHostName from rootDSE"));
                        return DNS_ERR(SERVER_FAILURE);
                }
 
-               recs[ri].data.soa.mname
-                       = talloc_steal(recs, dnsHostName);
+               recs[ri].data.soa.mname = talloc_strdup(recs, dnsHostName);
        }
 
        *records = recs;