rohc_comp_internals.h

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/*
 * Copyright 2010,2011,2012,2013,2014 Didier Barvaux
 * Copyright 2012,2013,2014 Viveris Technologies
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/**
 * @file    rohc_comp_internals.h
 * @brief   Internal structures for ROHC compression
 * @author  Didier Barvaux <didier.barvaux@toulouse.viveris.com>
 * @author  Didier Barvaux <didier@barvaux.org>
 */

#ifndef ROHC_COMP_INTERNALS_H
#define ROHC_COMP_INTERNALS_H

#include "rohc_internal.h"
#include "rohc_traces_internal.h"
#include "rohc_packets.h"
#include "rohc_comp.h"
#include "schemes/comp_wlsb.h"
#include "net_pkt.h"
#include "feedback.h"

#include <stdbool.h>


/*
 * Constants and macros
 */

/** The number of ROHC profiles ready to be used */
#define C_NUM_PROFILES 10U

/** The default maximal number of packets sent in > IR states (= FO and SO
 *  states) before changing back the state to IR (periodic refreshes) */
#define CHANGE_TO_IR_COUNT  1700

/** The default maximal delay (in ms) spent in > IR states (= FO and SO states)
 *  before changing back the state to IR (periodic refreshes) */
#define CHANGE_TO_IR_TIME  1000U

/** The default maximal number of packets sent in > FO states (= SO state)
 *  before changing back the state to FO (periodic refreshes) */
#define CHANGE_TO_FO_COUNT  700

/** The default maximal delay (in ms) spent in > FO states (= SO state)
 *  before changing back the state to FO (periodic refreshes) */
#define CHANGE_TO_FO_TIME  500U

/** The minimal number of packets that must be sent while in IR state before
 *  being able to switch to the FO state */
#define MAX_IR_COUNT  3U

/** The minimal number of packets that must be sent while in CR state before
 *  being able to switch to the FO state */
#define MAX_CR_COUNT  MAX_IR_COUNT

/** The minimal number of packets that must be sent while in FO state before
 *  being able to switch to the SO state */
#define MAX_FO_COUNT  3U

/** The minimal number of packets that must be sent while in INIT_STRIDE
 *  state before being able to switch to the SEND_SCALED state */
#define ROHC_INIT_TS_STRIDE_MIN  3U

/**
 * @brief Default number of transmission for lists to become a reference list
 *
 * The minimal number of times of compressed list shall be sent to become
 * a reference list. L is the name specified in the RFC.
 */
#define ROHC_LIST_DEFAULT_L  5U


/** Print a warning trace for the given compression context */
#define rohc_comp_warn(context, format, ...) \
        rohc_warning((context)->compressor, ROHC_TRACE_COMP, \
                     (context)->profile->id, \
                     format, ##__VA_ARGS__)

/** Print a debug trace for the given compression context */
#define rohc_comp_debug(context, format, ...) \
        rohc_debug((context)->compressor, ROHC_TRACE_COMP, \
                   (context)->profile->id, \
                   format, ##__VA_ARGS__)

/** Dump a buffer for the given compression context */
#define rohc_comp_dump_buf(context, descr, buf, buf_len) \
        do { \
                if(((context)->compressor->features & ROHC_COMP_FEATURE_DUMP_PACKETS) != 0) { \
                        rohc_dump_buf((context)->compressor->trace_callback, \
                                      (context)->compressor->trace_callback_priv, \
                                      ROHC_TRACE_COMP, ROHC_TRACE_DEBUG, \
                                      descr, buf, buf_len); \
                } \
        } while(0)


/*
 * Declare ROHC compression structures that are defined at the end of this
 * file but used by other structures at the beginning of the file.
 */

struct rohc_comp_ctxt;


/*
 * Definitions of ROHC compression structures
 */


/**
 * @brief The ROHC compressor
 */
struct rohc_comp
{
        /** The medium associated with the decompressor */
        struct rohc_medium medium;

        /** Enabled/disabled features for the compressor */
        rohc_comp_features_t features;

        /** The array of compression contexts that use the compressor */
        struct rohc_comp_ctxt *contexts;
        /** The number of compression contexts in use in the array */
        size_t num_contexts_used;

        /** Which profiles are enabled and with one are not? */
        bool enabled_profiles[C_NUM_PROFILES];


        /* CRC-related variables: */

        /** The table to enable fast CRC-3 computation */
        uint8_t crc_table_3[256];
        /** The table to enable fast CRC-7 computation */
        uint8_t crc_table_7[256];
        /** The table to enable fast CRC-8 computation */
        uint8_t crc_table_8[256];


        /* segment-related variables */

/** The maximal value for MRRU */
#define ROHC_MAX_MRRU 65535
        /** The remaining bytes of the Reconstructed Reception Unit (RRU) waiting
         *  to be split into segments */
        uint8_t rru[ROHC_MAX_MRRU];
        /** The offset of the remaining bytes in the RRU buffer */
        size_t rru_off;
        /** The number of the remaining bytes in the RRU buffer */
        size_t rru_len;


        /* variables related to RTP detection */

        /** The callback function used to detect RTP packet */
        rohc_rtp_detection_callback_t rtp_callback;
        /** Pointer to an external memory area provided/used by the callback user */
        void *rtp_private;


        /* some statistics about the compression process: */

        /** The number of sent packets */
        int num_packets;
        /** The size of all the received uncompressed IP packets */
        int total_uncompressed_size;
        /** The size of all the sent compressed ROHC packets */
        int total_compressed_size;

        /** The last context used by the compressor */
        struct rohc_comp_ctxt *last_context;


        /* random callback */

        /** The user-defined callback for random numbers */
        rohc_comp_random_cb_t random_cb;
        /** Private data that will be given to the callback for random numbers */
        void *random_cb_ctxt;


        /* user interaction variables: */

        /** The width of the W-LSB sliding window */
        size_t wlsb_window_width;
        /** The reorder offset specifies how much reordering is handled by the
         *  W-LSB encoding of the MSN in ROHCv2 profiles */
        rohc_reordering_offset_t reorder_ratio;
        /** The maximal number of packets sent in > IR states (= FO and SO
         *  states) before changing back the state to IR (periodic refreshes) */
        size_t periodic_refreshes_ir_timeout_pkts;
        /** The maximal delay spent in > IR states (= FO and SO states) before
         *  changing back the state to IR (periodic refreshes) */
        uint64_t periodic_refreshes_ir_timeout_time;
        /** The maximal number of packets sent in > FO states (= SO state)
         *  before changing back the state to FO (periodic refreshes) */
        size_t periodic_refreshes_fo_timeout_pkts;
        /** The maximal delay spent in > FO states (= SO state) before changing back
         *  the state to FO (periodic refreshes) */
        uint64_t periodic_refreshes_fo_timeout_time;
        /** Maximum Reconstructed Reception Unit */
        size_t mrru;
        /** The connection type (currently not used) */
        int connection_type;
        /** The number of uncompressed transmissions for list compression (L) */
        size_t list_trans_nr;

        /** The callback function used to manage traces */
        rohc_trace_callback2_t trace_callback;
        /** The private context of the callback function used to manage traces */
        void *trace_callback_priv;
};


/**
 * @brief The ROHC compression profile
 *
 * The object defines a ROHC profile. Each field must be filled in
 * for each new profile.
 */
struct rohc_comp_profile
{
        /** The profile ID as reserved by IANA */
        const rohc_profile_t id;

        /**
         * @brief The IP protocol ID used to find out which profile is able to
         *        compress an IP packet
         */
        const unsigned short protocol;

        /**
         * @brief The handler used to create the profile-specific part of the
         *        compression context from a given packet
         */
        bool (*create)(struct rohc_comp_ctxt *const context,
                       const struct net_pkt *const packet)
                __attribute__((warn_unused_result, nonnull(1, 2)));

        /**
         * @brief The handler used to create the profile-specific part of the
         *        compression context from a given context
         */
        bool (*clone)(struct rohc_comp_ctxt *const ctxt,
                 const struct rohc_comp_ctxt *const base_ctxt)
                __attribute__((warn_unused_result, nonnull(1, 2)));

        /**
         * @brief The handler used to destroy the profile-specific part of the
         *        compression context
         */
        void (*destroy)(struct rohc_comp_ctxt *const context)
                __attribute__((nonnull(1)));

        /**
         * @brief The handler used to check whether an uncompressed IP packet
         *        fits the current profile or not
         */
        bool (*check_profile)(const struct rohc_comp *const comp,
                              const struct net_pkt *const packet)
                __attribute__((warn_unused_result, nonnull(1, 2)));

        /**
         * @brief The handler used to check whether an uncompressed IP packet
         *        belongs to a context or not
         */
        bool (*check_context)(const struct rohc_comp_ctxt *const context,
                              const struct net_pkt *const packet,
                              size_t *const cr_score)
                __attribute__((warn_unused_result, nonnull(1, 2, 3)));

        /**
         * @brief The handler used to encode uncompressed IP packets
         *
         * @param context            The compression context
         * @param ip                 The IP packet to encode
         * @param packet_size        The length of the IP packet to encode
         * @param rohc_pkt           OUT: The ROHC packet
         * @param rohc_pkt_max_len   The maximum length of the ROHC packet
         * @param packet_type        OUT: The type of ROHC packet that is created
         * @param payload_offset     OUT: The offset for the payload in the IP packet
         * @return                   The length of the ROHC packet if successful,
         *                           -1 otherwise
         */
        int (*encode)(struct rohc_comp_ctxt *const context,
                      const struct net_pkt *const uncomp_pkt,
                      uint8_t *const rohc_pkt,
                      const size_t rohc_pkt_max_len,
                      rohc_packet_t *const packet_type,
                      size_t *const payload_offset)
                __attribute__((warn_unused_result, nonnull(1, 2, 3, 5, 6)));

        /**
         * @brief The handler used to warn the profile-specific part of the
         *        context about the arrival of feedback data
         */
        bool (*feedback)(struct rohc_comp_ctxt *const context,
                         const enum rohc_feedback_type feedback_type,
                         const uint8_t *const packet,
                         const size_t packet_len,
                         const uint8_t *const feedback_data,
                         const size_t feedback_data_len)
                __attribute__((warn_unused_result, nonnull(1, 3, 5)));
};


/**
 * @brief The ROHC compression context
 */
struct rohc_comp_ctxt
{
        /** Whether the context is in use or not */
        int used;
        /** The time when the context was created (in seconds) */
        uint64_t latest_used;
        /** The time when the context was last used (in seconds) */
        uint64_t first_used;

        /** The context unique ID (CID) */
        rohc_cid_t cid;

        /** The associated compressor */
        struct rohc_comp *compressor;

        /** The associated profile */
        const struct rohc_comp_profile *profile;
        /** Profile-specific data, defined by the profiles */
        void *specific;

        /** Whether Context Replication (CR) may be used */
        bool do_ctxt_replication;
        /** The base context for Context Replication (CR) */
        rohc_cid_t cr_base_cid;

        /** The operation mode in which the context operates among:
         *  ROHC_U_MODE, ROHC_O_MODE, ROHC_R_MODE */
        rohc_mode_t mode;
        /** The operation state in which the context operates: IR, FO, SO */
        rohc_comp_state_t state;

        /* below are some statistics */

        /* The type of ROHC packet created for the last compressed packet */
        rohc_packet_t packet_type;

        /** The number of packets sent while in Initialization & Refresh (IR) state */
        size_t ir_count;
        /** The number of packets sent while in First Order (FO) state */
        size_t fo_count;
        /** The number of packets sent while in Second Order (SO) state */
        size_t so_count;
        /** The number of packets sent while in Context Replication (CR) state */
        size_t cr_count;

        /**
         * @brief The number of packet sent while in SO state, used for the periodic
         *        refreshes of the context
         * @see rohc_comp_periodic_down_transition
         */
        size_t go_back_fo_count;
        /**
         * @brief The last time that the context was in FO state, used for the
         *        periodic refreshes of the context
         * @see rohc_comp_periodic_down_transition
         */
        struct rohc_ts go_back_fo_time;
        /**
         * @brief The number of packet sent while in FO or SO state, used for the
         *        periodic refreshes of the context
         * @see rohc_comp_periodic_down_transition
         */
        size_t go_back_ir_count;
        /**
         * @brief The last time that the context was in IR state, used for the
         *        periodic refreshes of the context
         * @see rohc_comp_periodic_down_transition
         */
        struct rohc_ts go_back_ir_time;

        /** The cumulated size of the uncompressed packets */
        int total_uncompressed_size;
        /** The cumulated size of the compressed packets */
        int total_compressed_size;
        /** The cumulated size of the uncompressed headers */
        int header_uncompressed_size;
        /** The cumulated size of the compressed headers */
        int header_compressed_size;

        /** The total size of the last uncompressed packet */
        int total_last_uncompressed_size;
        /** The total size of the last compressed packet */
        int total_last_compressed_size;
        /** The header size of the last uncompressed packet */
        int header_last_uncompressed_size;
        /** The header size of the last compressed packet */
        int header_last_compressed_size;

        /** The number of sent packets */
        int num_sent_packets;
};


void rohc_comp_change_mode(struct rohc_comp_ctxt *const context,
                           const rohc_mode_t new_mode)
        __attribute__((nonnull(1)));

void rohc_comp_change_state(struct rohc_comp_ctxt *const context,
                            const rohc_comp_state_t new_state)
        __attribute__((nonnull(1)));

void rohc_comp_periodic_down_transition(struct rohc_comp_ctxt *const context,
                                        const struct rohc_ts pkt_time)
        __attribute__((nonnull(1)));

bool rohc_comp_reinit_context(struct rohc_comp_ctxt *const context)
        __attribute__((warn_unused_result, nonnull(1)));

bool rohc_comp_feedback_parse_opts(const struct rohc_comp_ctxt *const context,
                                   const uint8_t *const packet,
                                   const size_t packet_len,
                                   const uint8_t *const feedback_data,
                                   const size_t feedback_data_len,
                                   size_t opts_present[ROHC_FEEDBACK_OPT_MAX],
                                   uint32_t *const sn_bits,
                                   size_t *const sn_bits_nr,
                                   const rohc_feedback_crc_t crc_type,
                                   uint8_t crc_in_packet,
                                   size_t crc_pos_from_end)
        __attribute__((warn_unused_result, nonnull(1, 2, 4, 6, 7, 8)));

#endif