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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);
}
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