policy.DEBUG: add also policy.REQTRACE for printing incoming packets

doc/config-logging-monitoring.rst

@@ -14,7 +14,7 @@ so by default logs from Knot Resolver should contain only couple lines a day.
 For debugging purposes it is possible to enable very verbose logging using
 :func:`verbose` function.
 
-.. function:: verbose([true | false])
+.. py:function:: verbose([true | false])
 
    :param: ``true`` to enable, ``false`` to disable verbose logging.
    :return: boolean Current state of verbose logging.

modules/policy/README.rst

@@ -178,6 +178,10 @@ Following actions act on request and then processing continue until first non-ch
         -- requests for example.net. and its subdomains
         policy.add(policy.suffix(policy.QTRACE, policy.todnames({'example.net'})))
 
+.. py:attribute:: REQTRACE
+
+   Pretty-print DNS requests from clients into the verbose log. It's useful for debugging weird DNS clients. Verbose logging must be enabled using :func:`verbose` for this policy to be effective. It makes most sense together with :ref:`mod-view`.
+
 .. py:attribute:: DEBUG_ALWAYS
 
    Enable extra verbose logging for all requests, including cache hits. See caveats for :func:`policy.DEBUG_IF`.

modules/policy/policy.lua

@@ -542,10 +542,17 @@ local debug_logfinish_cb = ffi.cast('trace_callback_f', function (req)
 		tostring(req.answer))
 end)
 
+-- log request packet
+function policy.REQTRACE(_, req)
+	ffi.C.kr_log_req(req, 0, 0, 'dbg', 'request packet:\n%s',
+		tostring(req.qsource.packet))
+end
+
 function policy.DEBUG_ALWAYS(_, req)
 	policy.QTRACE(_, req)
 	req.trace_log = debug_logline_cb
 	req.trace_finish = debug_logfinish_cb
+	policy.REQTRACE(_, req)
 	return
 end
 
@@ -567,6 +574,7 @@ function policy.DEBUG_IF(test)
 			req.trace_log:free()
 			req.trace_finish:free()
 		end)
+		policy.REQTRACE(state, req)
 		return
 	end
 end