[1299] handled IXFR 'serial uptodate' case

src/bin/xfrin/tests/xfrin_test.py

@@ -352,6 +352,37 @@ class TestXfrinInitialSOA(TestXfrinState):
         self.assertRaises(XfrinProtocolError, self.state.handle_rr, self.conn,
                           self.ns_rrset)
 
+    def test_handle_ixfr_uptodate(self):
+        self.conn._request_type = RRType.IXFR()
+        self.conn._request_serial = isc.dns.Serial(1234) # same as soa_rrset
+        self.assertTrue(self.state.handle_rr(self.conn, soa_rrset))
+        self.assertEqual(type(XfrinIXFRUptodate()),
+                         type(self.conn.get_xfrstate()))
+
+    def test_handle_ixfr_uptodate2(self):
+        self.conn._request_type = RRType.IXFR()
+        self.conn._request_serial = isc.dns.Serial(1235) # > soa_rrset
+        self.assertTrue(self.state.handle_rr(self.conn, soa_rrset))
+        self.assertEqual(type(XfrinIXFRUptodate()),
+                         type(self.conn.get_xfrstate()))
+
+    def test_handle_ixfr_uptodate3(self):
+        # Similar to the previous case, but checking serial number arithmetic
+        # comparison
+        self.conn._request_type = RRType.IXFR()
+        self.conn._request_serial = isc.dns.Serial(0xffffffff)
+        self.assertTrue(self.state.handle_rr(self.conn, soa_rrset))
+        self.assertEqual(type(XfrinFirstData()),
+                         type(self.conn.get_xfrstate()))
+
+    def test_handle_axfr_uptodate(self):
+        # "request serial" should matter only for IXFR
+        self.conn._request_type = RRType.AXFR()
+        self.conn._request_serial = isc.dns.Serial(1234) # same as soa_rrset
+        self.assertTrue(self.state.handle_rr(self.conn, soa_rrset))
+        self.assertEqual(type(XfrinFirstData()),
+                         type(self.conn.get_xfrstate()))
+
     def test_finish_message(self):
         self.assertTrue(self.state.finish_message(self.conn))
 
@@ -523,6 +554,19 @@ class TestXfrinIXFREnd(TestXfrinState):
     def test_finish_message(self):
         self.assertFalse(self.state.finish_message(self.conn))
 
+class TestXfrinIXFREnd(TestXfrinState):
+    def setUp(self):
+        super().setUp()
+        self.state = XfrinIXFRUptodate()
+
+    def test_handle_rr(self):
+        self.assertRaises(XfrinProtocolError, self.state.handle_rr, self.conn,
+                          self.ns_rrset)
+
+    def test_finish_message(self):
+        self.assertRaises(XfrinZoneUptodate, self.state.finish_message,
+                          self.conn)
+
 class TestXfrinAXFR(TestXfrinState):
     def setUp(self):
         super().setUp()
@@ -1488,6 +1532,16 @@ class TestIXFRResponse(TestXfrinConnection):
                     [[('delete', begin_soa_rrset), ('add', soa_rrset)]],
                     self.conn._datasrc_client.committed_diffs)
 
+    def test_ixfr_response_uptodate(self):
+        '''IXFR response indicates the zone is new enough'''
+        self.conn.reply_data = self.conn.create_response_data(
+            questions=[Question(TEST_ZONE_NAME, TEST_RRCLASS, RRType.IXFR())],
+            answers=[begin_soa_rrset])
+        self.assertRaises(XfrinZoneUptodate, self.conn._handle_xfrin_responses)
+        # no diffs should have been committed
+        check_diffs(self.assertEqual,
+                    [], self.conn._datasrc_client.committed_diffs)
+
     def test_ixfr_response_broken(self):
         '''Test with a broken response.
 
@@ -1520,6 +1574,22 @@ class TestIXFRResponse(TestXfrinConnection):
                     [[('delete', begin_soa_rrset), ('add', soa_rrset)]],
                     self.conn._datasrc_client.committed_diffs)
 
+    def test_ixfr_response_uptodate_extra(self):
+        '''Similar to 'uptodate' test, but with extra bogus data.
+
+        In either case an exception will be raised, but in this case it's
+        considered an error.
+
+        '''
+        self.conn.reply_data = self.conn.create_response_data(
+            questions=[Question(TEST_ZONE_NAME, TEST_RRCLASS, RRType.IXFR())],
+            answers=[begin_soa_rrset, soa_rrset])
+        self.assertRaises(XfrinProtocolError,
+                          self.conn._handle_xfrin_responses)
+        # no diffs should have been committed
+        check_diffs(self.assertEqual,
+                    [], self.conn._datasrc_client.committed_diffs)
+
     def test_ixfr_to_axfr_response(self):
         '''AXFR-style IXFR response.
 
@@ -1623,13 +1693,25 @@ class TestIXFRSession(TestXfrinConnection):
         self.conn.response_generator = create_ixfr_response
         self.assertEqual(XFRIN_FAIL, self.conn.do_xfrin(False, RRType.IXFR()))
 
-    def test_do_xfrin_fail(self):
+    def test_do_xfrin_fail2(self):
         '''IXFR fails due to a bogus DNS message.
 
         '''
         self._create_broken_response_data()
         self.assertEqual(XFRIN_FAIL, self.conn.do_xfrin(False, RRType.IXFR()))
 
+    def test_do_xfrin_uptodate(self):
+        '''IXFR is (gracefully) aborted because serial is not new
+
+        '''
+        def create_response():
+            self.conn.reply_data = self.conn.create_response_data(
+                questions=[Question(TEST_ZONE_NAME, TEST_RRCLASS,
+                                    RRType.IXFR())],
+                answers=[begin_soa_rrset])
+        self.conn.response_generator = create_response
+        self.assertEqual(XFRIN_OK, self.conn.do_xfrin(False, RRType.IXFR()))
+
 class TestXFRSessionWithSQLite3(TestXfrinConnection):
     '''Tests for XFR sessions using an SQLite3 DB.
 

src/bin/xfrin/xfrin.py.in

@@ -188,12 +188,12 @@ class XfrinState:
                              (AXFR or
             (recv SOA)        AXFR-style IXFR)  (SOA, add)
     InitialSOA------->FirstData------------->AXFR--------->AXFREnd
-                          |                  |  ^         (post xfr
-                          |                  |  |        checks, then
-                          |                  +--+        commit)
-                          |            (non SOA, add)
-                          |
-                          |                     (non SOA, delete)
+         |                |                  |  ^         (post xfr
+         |(IXFR &&        |                  |  |        checks, then
+         | recv SOA       |                  +--+        commit)
+         | not new)       |            (non SOA, add)
+         V                |
+    IXFRUptodate          |                     (non SOA, delete)
                (pure IXFR,|                           +-------+
             keep handling)|             (Delete SOA)  V       |
                           + ->IXFRDeleteSOA------>IXFRDelete--+
@@ -307,13 +307,14 @@ class XfrinInitialSOA(XfrinState):
                                      + rr.get_type().to_text() + ' received)')
         conn._end_serial = get_soa_serial(rr.get_rdata()[0])
 
-        # FIXME: we need to check the serial is actually greater than ours.
-        # To do so, however, we need to implement serial number arithmetic.
-        # Although it wouldn't be a big task, we'll leave it for a separate
-        # task for now.  (Always performing xfr could be inefficient, but
-        # shouldn't do any harm otherwise)
+        if conn._request_type == RRType.IXFR() and \
+                conn._end_serial <= conn._request_serial:
+            logger.info(XFRIN_IXFR_UPTODATE, conn.zone_str(),
+                        conn._request_serial, conn._end_serial)
+            self.set_xfrstate(conn, XfrinIXFRUptodate())
+        else:
+            self.set_xfrstate(conn, XfrinFirstData())
 
-        self.set_xfrstate(conn, XfrinFirstData())
         return True
 
 class XfrinFirstData(XfrinState):
@@ -437,6 +438,14 @@ class XfrinIXFREnd(XfrinState):
         '''
         return False
 
+class XfrinIXFRUptodate(XfrinState):
+    def handle_rr(self, conn, rr):
+        raise XfrinProtocolError('Extra data after single IXFR response ' +
+                                 rr.to_text())
+
+    def finish_message(self, conn):
+        raise XfrinZoneUptodate
+
 class XfrinAXFR(XfrinState):
     def handle_rr(self, conn, rr):
         """

src/bin/xfrin/xfrin_messages.mes

@@ -163,6 +163,16 @@ daemon will now shut down.
 An uncaught exception was raised while running the xfrin daemon. The
 exception message is printed in the log message.
 
+% XFRIN_IXFR_UPTODATE IXFR requested serial for %1 is %2, master has %3, not updating
+The first SOA record in an IXFR response indicates the zone's serial
+at the primary server is not newer than the client's.  This is
+basically unexpected event because normally the client first checks
+the SOA serial by an SOA query, but can still happen if the transfer
+is manually invoked or (although unlikely) there is a rapid change at
+the primary server between the SOA and IXFR queries.  The client
+implementation confirms the whole response is this single SOA, and
+aborts the transfer just like a successful case.
+
 % XFRIN_GOT_INCREMENTAL_RESP got incremental response for %1
 In an attempt of IXFR processing, the begenning SOA of the first difference
 (following the initial SOA that specified the final SOA for all the