s4:dns_server: add DNS_TYPE_TOMBSTONE support to dns_common_replace()

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10749

Pair-Programmed-With: Michael Adam <obnox@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/source4/dns_server/dnsserver_common.c b/source4/dns_server/dnsserver_common.c
index 286673434711588b24aa479ac65689e7d7a3079a..c49d6ec87a6862bc42694aeea21617a9725a4734 100644 (file)
--- a/source4/dns_server/dnsserver_common.c
+++ b/source4/dns_server/dnsserver_common.c
@@ -190,6 +190,22 @@ WERROR dns_common_lookup(struct ldb_context *samdb,
        return WERR_OK;
 }
 
+static int rec_cmp(const struct dnsp_DnssrvRpcRecord *r1,
+                  const struct dnsp_DnssrvRpcRecord *r2)
+{
+       if (r1->wType != r2->wType) {
+               /*
+                * The records are sorted with higher types first
+                */
+               return r2->wType - r1->wType;
+       }
+
+       /*
+        * Then we need to sort from the oldest to newest timestamp
+        */
+       return r1->dwTimeStamp - r2->dwTimeStamp;
+}
+
 WERROR dns_common_replace(struct ldb_context *samdb,
                          TALLOC_CTX *mem_ctx,
                          struct ldb_dn *dn,
@@ -202,6 +218,8 @@ WERROR dns_common_replace(struct ldb_context *samdb,
        uint16_t i;
        int ret;
        struct ldb_message *msg = NULL;
+       bool was_tombstoned = false;
+       bool become_tombstoned = false;
 
        msg = ldb_msg_new(mem_ctx);
        W_ERROR_HAVE_NO_MEMORY(msg);
@@ -213,17 +231,30 @@ WERROR dns_common_replace(struct ldb_context *samdb,
                return DNS_ERR(SERVER_FAILURE);
        }
 
-       el->values = talloc_zero_array(el, struct ldb_val, rec_count);
+       /*
+        * we have at least one value,
+        * which might be used for the tombstone marker
+        */
+       el->values = talloc_zero_array(el, struct ldb_val, MAX(1, rec_count));
        if (rec_count > 0) {
                W_ERROR_HAVE_NO_MEMORY(el->values);
+
+               /*
+                * We store a sorted list with the high wType values first
+                * that's what windows does. It also simplifies the
+                * filtering of DNS_TYPE_TOMBSTONE records
+                */
+               TYPESAFE_QSORT(records, rec_count, rec_cmp);
        }
 
        for (i = 0; i < rec_count; i++) {
-               static const struct dnsp_DnssrvRpcRecord zero;
                struct ldb_val *v = &el->values[el->num_values];
                enum ndr_err_code ndr_err;
 
-               if (memcmp(&records[i], &zero, sizeof(zero)) == 0) {
+               if (records[i].wType == DNS_TYPE_TOMBSTONE) {
+                       if (records[i].data.timestamp != 0) {
+                               was_tombstoned = true;
+                       }
                        continue;
                }
 
@@ -256,7 +287,49 @@ WERROR dns_common_replace(struct ldb_context *samdb,
        }
 
        if (el->num_values == 0) {
-               el->flags = LDB_FLAG_MOD_DELETE;
+               struct dnsp_DnssrvRpcRecord tbs;
+               struct ldb_val *v = &el->values[el->num_values];
+               enum ndr_err_code ndr_err;
+               struct timeval tv;
+
+               if (was_tombstoned) {
+                       /*
+                        * This is already a tombstoned object.
+                        * Just leave it instead of updating the time stamp.
+                        */
+                       return WERR_OK;
+               }
+
+               tv = timeval_current();
+               tbs = (struct dnsp_DnssrvRpcRecord) {
+                       .wType = DNS_TYPE_TOMBSTONE,
+                       .dwSerial = serial,
+                       .data.timestamp = timeval_to_nttime(&tv),
+               };
+
+               ndr_err = ndr_push_struct_blob(v, el->values, &tbs,
+                               (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
+               if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+                       DEBUG(0, ("Failed to push dnsp_DnssrvRpcRecord\n"));
+                       return DNS_ERR(SERVER_FAILURE);
+               }
+               el->num_values++;
+
+               become_tombstoned = true;
+       }
+
+       if (was_tombstoned || become_tombstoned) {
+               ret = ldb_msg_add_empty(msg, "dNSTombstoned",
+                                       LDB_FLAG_MOD_REPLACE, NULL);
+               if (ret != LDB_SUCCESS) {
+                       return DNS_ERR(SERVER_FAILURE);
+               }
+
+               ret = ldb_msg_add_fmt(msg, "dNSTombstoned", "%s",
+                                     become_tombstoned ? "TRUE" : "FALSE");
+               if (ret != LDB_SUCCESS) {
+                       return DNS_ERR(SERVER_FAILURE);
+               }
        }
 
        ret = ldb_modify(samdb, msg);