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-rw-r--r--src/knot/query/layer.h136
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diff --git a/src/knot/query/layer.h b/src/knot/query/layer.h
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+/* 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);
+}