1 files changed, 136 insertions, 0 deletions
diff --git a/src/knot/query/layer.h b/src/knot/query/layer.h
new file mode 100644
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--- /dev/null
+++ b/src/knot/query/layer.h
@@ -0,0 +1,136 @@
+/*  Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "libknot/packet/pkt.h"
+#include "libknot/mm_ctx.h"
+#include "knot/nameserver/tsig_ctx.h"
+
+/*!
+ * \brief Layer processing states.
+ *
+ * Each state represents the state machine transition,
+ * and determines readiness for the next action.
+ */
+typedef enum {
+	KNOT_STATE_NOOP = 0,   //!< Invalid.
+	KNOT_STATE_CONSUME,    //!< Consume data.
+	KNOT_STATE_PRODUCE,    //!< Produce data.
+	KNOT_STATE_RESET,      //!< Restart processing.
+	KNOT_STATE_DONE,       //!< Finished.
+	KNOT_STATE_FAIL,       //!< Error.
+	KNOT_STATE_FINAL,      //!< Finished and finalized.
+	KNOT_STATE_IGNORE,     //!< Data has been ignored.
+} knot_layer_state_t;
+
+typedef struct knot_layer_api knot_layer_api_t;
+
+/*! \brief Packet processing context. */
+typedef struct {
+	const knot_layer_api_t *api;  //!< Layer API.
+	knot_mm_t *mm;                //!< Processing memory context.
+	knot_layer_state_t state;     //!< Processing state.
+	void *data;                   //!< Module specific.
+	tsig_ctx_t *tsig;             //!< TODO: remove
+	unsigned flags;               //!< Custom flags.
+} knot_layer_t;
+
+/*! \brief Packet processing module API. */
+struct knot_layer_api {
+	int (*begin)(knot_layer_t *ctx, void *params);
+	int (*reset)(knot_layer_t *ctx);
+	int (*finish)(knot_layer_t *ctx);
+	int (*consume)(knot_layer_t *ctx, knot_pkt_t *pkt);
+	int (*produce)(knot_layer_t *ctx, knot_pkt_t *pkt);
+};
+
+/*! \brief Helper for conditional layer call. */
+#define LAYER_CALL(layer, func, ...) \
+	assert(layer->api); \
+	if (layer->api->func) { \
+		layer->state = layer->api->func(layer, ##__VA_ARGS__); \
+	}
+
+/*!
+ * \brief Initialize packet processing context.
+ *
+ * \param ctx Layer context.
+ * \param mm  Memory context.
+ * \param api Layer API.
+ */
+inline static void knot_layer_init(knot_layer_t *ctx, knot_mm_t *mm,
+                                   const knot_layer_api_t *api)
+{
+	memset(ctx, 0, sizeof(*ctx));
+
+	ctx->mm = mm;
+	ctx->api = api;
+	ctx->state = KNOT_STATE_NOOP;
+}
+
+/*!
+ * \brief Prepare packet processing.
+ *
+ * \param ctx Layer context.
+ * \param params Initialization params.
+ */
+inline static void knot_layer_begin(knot_layer_t *ctx, void *params)
+{
+	LAYER_CALL(ctx, begin, params);
+}
+
+/*!
+ * \brief Reset current packet processing context.
+ *
+ * \param ctx Layer context.
+ */
+inline static void knot_layer_reset(knot_layer_t *ctx)
+{
+	LAYER_CALL(ctx, reset);
+}
+
+/*!
+ * \brief Finish and close packet processing context.
+ *
+ * \param ctx Layer context.
+ */
+inline static void knot_layer_finish(knot_layer_t *ctx)
+{
+	LAYER_CALL(ctx, finish);
+}
+
+/*!
+ * \brief Add more data to layer processing.
+ *
+ * \param ctx Layer context.
+ * \param pkt Data packet.
+ */
+inline static void knot_layer_consume(knot_layer_t *ctx, knot_pkt_t *pkt)
+{
+	LAYER_CALL(ctx, consume, pkt);
+}
+
+/*!
+ * \brief Generate output from layer.
+ *
+ * \param ctx Layer context.
+ * \param pkt Data packet.
+ */
+inline static void knot_layer_produce(knot_layer_t *ctx, knot_pkt_t *pkt)
+{
+	LAYER_CALL(ctx, produce, pkt);
+}