rohc_comp.h

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/*
 * Copyright 2010,2012,2013,2014 Didier Barvaux
 * Copyright 2013 Friedrich
 * Copyright 2009,2010 Thales Communications
 * Copyright 2007,2009,2010,2012,2013,2014,2017 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.h
 * @brief ROHC compression routines
 * @author Didier Barvaux <didier.barvaux@toulouse.viveris.com>
 * @author Didier Barvaux <didier@barvaux.org>
 */

#ifndef ROHC_COMP_H
#define ROHC_COMP_H

#ifdef __cplusplus
extern "C"
{
#endif

#include <rohc/rohc.h>
#include <rohc/rohc_packets.h>
#include <rohc/rohc_traces.h>
#include <rohc/rohc_time.h>
#include <rohc/rohc_buf.h>

#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>


/** Macro that handles DLL export declarations gracefully */
#ifdef DLL_EXPORT /* passed by autotools on command line */
#  define ROHC_EXPORT __declspec(dllexport)
#else
#  define ROHC_EXPORT
#endif


/*
 * Declare the private ROHC compressor structure that is defined inside the
 * library.
 */

struct rohc_comp;


/*
 * Public structures and types
 */


/**
 * @brief The different ROHC compressor states
 *
 * The different ROHC operation states at compressor as defined in section
 * 4.3.1 of RFC 3095. The CR operation state is defined in RFC 4164.
 *
 * If you add a new compressor state, please also add the corresponding
 * textual description in \ref rohc_comp_get_state_descr.
 *
 * @ingroup rohc_comp
 *
 * @see rohc_comp_get_state_descr
 */
typedef enum
{
        /** Unknown compressor state */
        ROHC_COMP_STATE_UNKNOWN = 0,
        /** The Initialization and Refresh (IR) compressor state */
        ROHC_COMP_STATE_IR = 1,
        /** The First Order (FO) compressor state */
        ROHC_COMP_STATE_FO = 2,
        /** The Second Order (SO) compressor state */
        ROHC_COMP_STATE_SO = 3,
        /** The Context Replication (CR) compressor state */
        ROHC_COMP_STATE_CR = 4,

} rohc_comp_state_t;


/**
 * @brief Some information about the last compressed packet
 *
 * The structure is used by the \ref rohc_comp_get_last_packet_info2 function
 * to store some information about the last compressed packet.
 *
 * Versioning works as follow:
 *  - The \e version_major field defines the compatibility level. If the major
 *    number given by user does not match the one expected by the library,
 *    an error is returned.
 *  - The \e version_minor field defines the extension level. If the minor
 *    number given by user does not match the one expected by the library,
 *    only the fields supported in that minor version will be filled by
 *    \ref rohc_comp_get_last_packet_info2.
 *
 * Notes for developers:
 *  - Increase the major version if a field is removed.
 *  - Increase the major version if a field is added at the beginning or in
 *    the middle of the structure.
 *  - Increase the minor version if a field is added at the very end of the
 *    structure.
 *  - The version_major and version_minor fields must be located at the very
 *    beginning of the structure.
 *  - The structure must be packed.
 *
 * Supported versions:
 *  - Major 0 / Minor 0 contains: version_major, version_minor, context_id,
 *    is_context_init, context_mode, context_state, context_used, profile_id,
 *    packet_type, total_last_uncomp_size, header_last_uncomp_size,
 *    total_last_comp_size, and header_last_comp_size
 *
 * @ingroup rohc_comp
 *
 * @see rohc_comp_get_last_packet_info2
 */
typedef struct
{
        /** The major version of this structure */
        unsigned short version_major;
        /** The minor version of this structure */
        unsigned short version_minor;
        /** The Context ID (CID) */
        unsigned int context_id;
        /** Whether the context was initialized (created/re-used) by the packet */
        bool is_context_init;
        /** The mode of the last context used by the compressor */
        rohc_mode_t context_mode;
        /** The state of the last context used by the compressor */
        rohc_comp_state_t context_state;
        /** Whether the last context used by the compressor is still in use */
        bool context_used;
        /** The profile ID of the last context used by the compressor */
        int profile_id;
        /** The type of ROHC packet created for the last compressed packet */
        rohc_packet_t packet_type;
        /** The uncompressed size (in bytes) of the last compressed packet */
        unsigned long total_last_uncomp_size;
        /** The uncompressed size (in bytes) of the last compressed header */
        unsigned long header_last_uncomp_size;
        /** The compressed size (in bytes) of the last compressed packet */
        unsigned long total_last_comp_size;
        /** The compressed size (in bytes) of the last compressed header */
        unsigned long header_last_comp_size;
} __attribute__((packed)) rohc_comp_last_packet_info2_t;


/**
 * @brief Some general information about the compressor
 *
 * The structure is used by the \ref rohc_comp_get_general_info function
 * to store some general information about the compressor.
 *
 * Versioning works as follow:
 *  - The \e version_major field defines the compatibility level. If the major
 *    number given by user does not match the one expected by the library,
 *    an error is returned.
 *  - The \e version_minor field defines the extension level. If the minor
 *    number given by user does not match the one expected by the library,
 *    only the fields supported in that minor version will be filled by
 *    \ref rohc_comp_get_general_info.
 *
 * Notes for developers:
 *  - Increase the major version if a field is removed.
 *  - Increase the major version if a field is added at the beginning or in
 *    the middle of the structure.
 *  - Increase the minor version if a field is added at the very end of the
 *    structure.
 *  - The version_major and version_minor fields must be located at the very
 *    beginning of the structure.
 *  - The structure must be packed.
 *
 * Supported versions:
 *  - major 0 and minor = 0 contains: version_major, version_minor,
 *    contexts_nr, packets_nr, uncomp_bytes_nr, and comp_bytes_nr.
 *
 * @ingroup rohc_comp
 *
 * @see rohc_comp_get_general_info
 */
typedef struct
{
        /** The major version of this structure */
        unsigned short version_major;
        /** The minor version of this structure */
        unsigned short version_minor;
        /** The number of contexts used by the compressor */
        size_t contexts_nr;
        /** The number of packets processed by the compressor */
        unsigned long packets_nr;
        /** The number of uncompressed bytes received by the compressor */
        unsigned long uncomp_bytes_nr;
        /** The number of compressed bytes produced by the compressor */
        unsigned long comp_bytes_nr;
} __attribute__((packed)) rohc_comp_general_info_t;


/**
 * @brief The different features of the ROHC compressor
 *
 * Features for the ROHC compressor control whether mechanisms defined as
 * optional by RFCs are enabled or not. They can be set or unset with the
 * function \ref rohc_comp_set_features.
 *
 * @ingroup rohc_comp
 *
 * @see rohc_comp_set_features
 */
typedef enum
{
        /** No feature at all */
        ROHC_COMP_FEATURE_NONE            = 0,
        /** Be compatible with 1.6.x versions */
        ROHC_COMP_FEATURE_COMPAT_1_6_x    = (1 << 0),
        /** Do not check IP checksums at compressor */
        ROHC_COMP_FEATURE_NO_IP_CHECKSUMS = (1 << 2),
        /** Dump content of packets in traces (beware: performance impact) */
        ROHC_COMP_FEATURE_DUMP_PACKETS    = (1 << 3),
        /** Allow periodic refreshes based on inter-packet time */
        ROHC_COMP_FEATURE_TIME_BASED_REFRESHES = (1 << 4),

} rohc_comp_features_t;


/**
 * @brief The prototype of the RTP detection callback
 *
 * User-defined function that is called by the ROHC library for every UDP
 * packet to determine whether the UDP packet transports RTP data. If the
 * function returns true, the RTP profile is used to compress the packet.
 * Otherwise the UDP profile is used.
 *
 * The user-defined function is set by calling the function
 * \ref rohc_comp_set_rtp_detection_cb
 *
 * @param ip           The innermost IP packet
 * @param udp          The UDP header of the packet
 * @param payload      The UDP payload of the packet
 * @param payload_size The size of the UDP payload (in bytes)
 * @param rtp_private  A pointer to a memory area to be used by the callback
 *                     function, may be NULL.
 * @return             true if the packet is an RTP packet, false otherwise
 *
 * @see rohc_comp_set_rtp_detection_cb
 * @ingroup rohc_comp
 */
typedef bool (*rohc_rtp_detection_callback_t)(const unsigned char *const ip,
                                              const unsigned char *const udp,
                                              const unsigned char *const payload,
                                              const unsigned int payload_size,
                                              void *const rtp_private)
        __attribute__((warn_unused_result));


/**
 * @brief The prototype of the callback for random numbers
 *
 * User-defined function that is called when the ROHC library requires a random
 * number. Currently, the ROHC library uses it when initializing the Sequence
 * Number (SN) of contexts using the IP-only, IP/UDP, and IP/UDP-Lite profiles.
 *
 * The user-defined function is set by calling the function
 * \ref rohc_comp_new2
 *
 * @param comp          The ROHC compressor
 * @param user_context  The context given by the user when he/she called the
 *                      \ref rohc_comp_new2 function, may be NULL.
 *
 * @see rohc_comp_new2
 * @ingroup rohc_comp
 */
typedef int (*rohc_comp_random_cb_t) (const struct rohc_comp *const comp,
                                      void *const user_context)
        __attribute__((warn_unused_result));


/*
 * Prototypes of main public functions related to ROHC compression
 */

struct rohc_comp * ROHC_EXPORT rohc_comp_new2(const rohc_cid_type_t cid_type,
                                              const rohc_cid_t max_cid,
                                              const rohc_comp_random_cb_t rand_cb,
                                              void *const rand_priv)
        __attribute__((warn_unused_result));

void ROHC_EXPORT rohc_comp_free(struct rohc_comp *const comp);

bool ROHC_EXPORT rohc_comp_set_traces_cb2(struct rohc_comp *const comp,
                                          rohc_trace_callback2_t callback,
                                          void *const priv_ctxt)
        __attribute__((warn_unused_result));

rohc_status_t ROHC_EXPORT rohc_compress4(struct rohc_comp *const comp,
                                         const struct rohc_buf uncomp_packet,
                                         struct rohc_buf *const rohc_packet)
        __attribute__((warn_unused_result));

rohc_status_t ROHC_EXPORT rohc_comp_pad(struct rohc_comp *const comp,
                                        struct rohc_buf *const rohc_packet,
                                        const size_t min_pkt_len)
        __attribute__((warn_unused_result));

rohc_status_t ROHC_EXPORT rohc_comp_get_segment2(struct rohc_comp *const comp,
                                                 struct rohc_buf *const segment)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_force_contexts_reinit(struct rohc_comp *const comp)
        __attribute__((warn_unused_result));


/*
 * Prototypes of public functions related to user interaction
 */

bool ROHC_EXPORT rohc_comp_profile_enabled(const struct rohc_comp *const comp,
                                           const rohc_profile_t profile)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_enable_profile(struct rohc_comp *const comp,
                                          const rohc_profile_t profile)
        __attribute__((warn_unused_result));
bool ROHC_EXPORT rohc_comp_disable_profile(struct rohc_comp *const comp,
                                           const rohc_profile_t profile)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_enable_profiles(struct rohc_comp *const comp,
                                           ...)
        __attribute__((warn_unused_result));
bool ROHC_EXPORT rohc_comp_disable_profiles(struct rohc_comp *const comp,
                                            ...)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_mrru(struct rohc_comp *const comp,
                                    const size_t mrru)
        __attribute__((warn_unused_result));
bool ROHC_EXPORT rohc_comp_get_mrru(const struct rohc_comp *const comp,
                                    size_t *const mrru)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_get_max_cid(const struct rohc_comp *const comp,
                                       size_t *const max_cid)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_get_cid_type(const struct rohc_comp *const comp,
                                        rohc_cid_type_t *const cid_type)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_rtp_detection_cb(struct rohc_comp *const comp,
                                                rohc_rtp_detection_callback_t callback,
                                                void *const rtp_private)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_features(struct rohc_comp *const comp,
                                        const rohc_comp_features_t features)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_deliver_feedback2(struct rohc_comp *const comp,
                                             const struct rohc_buf feedback)
        __attribute__((warn_unused_result));


/*
 * Prototypes of public functions that configure robustness to packet
 * loss/damage
 */

bool ROHC_EXPORT rohc_comp_set_wlsb_window_width(struct rohc_comp *const comp,
                                                 const size_t width)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_periodic_refreshes(struct rohc_comp *const comp,
                                                  const size_t ir_timeout,
                                                  const size_t fo_timeout)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_periodic_refreshes_time(struct rohc_comp *const comp,
                                                       const uint64_t ir_timeout,
                                                       const uint64_t fo_timeout)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_set_list_trans_nr(struct rohc_comp *const comp,
                                             const size_t list_trans_nr)
        __attribute__((warn_unused_result));


/*
 * Prototypes of public functions related to ROHC compression statistics
 */

bool ROHC_EXPORT rohc_comp_get_general_info(const struct rohc_comp *const comp,
                                            rohc_comp_general_info_t *const info)
        __attribute__((warn_unused_result));

bool ROHC_EXPORT rohc_comp_get_last_packet_info2(const struct rohc_comp *const comp,
                                                 rohc_comp_last_packet_info2_t *const info)
        __attribute__((warn_unused_result));

const char * ROHC_EXPORT rohc_comp_get_state_descr(const rohc_comp_state_t state)
        __attribute__((warn_unused_result, const));


#undef ROHC_EXPORT /* do not pollute outside this header */

#ifdef __cplusplus
}
#endif

#endif /* ROHC_COMP_H */