mpf_rtcp_packet.h

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/*
 * Copyright 2008-2015 Arsen Chaloyan
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef MPF_RTCP_PACKET_H
#define MPF_RTCP_PACKET_H

/**
 * @file mpf_rtcp_packet.h
 * @brief RTCP Packet Definition
 */ 

#include "mpf_rtp_stat.h"

APT_BEGIN_EXTERN_C


/** RTCP payload (packet) types */
typedef enum {
    RTCP_SR   = 200,
    RTCP_RR   = 201,
    RTCP_SDES = 202,
    RTCP_BYE  = 203,
    RTCP_APP  = 204
} rtcp_type_e;

/** RTCP SDES types */
typedef enum {
    RTCP_SDES_END   = 0,
    RTCP_SDES_CNAME = 1,
    RTCP_SDES_NAME  = 2,
    RTCP_SDES_EMAIL = 3,
    RTCP_SDES_PHONE = 4,
    RTCP_SDES_LOC   = 5,
    RTCP_SDES_TOOL  = 6,
    RTCP_SDES_NOTE  = 7,
    RTCP_SDES_PRIV  = 8
} rtcp_sdes_type_e;

/** RTCP header declaration */
typedef struct rtcp_header_t rtcp_header_t;
/** RTCP packet declaration */
typedef struct rtcp_packet_t rtcp_packet_t;
/** SDES item declaration*/
typedef struct rtcp_sdes_item_t rtcp_sdes_item_t;


/** RTCP header */
struct rtcp_header_t {
#if (APR_IS_BIGENDIAN == 1)
    /** protocol version */
    unsigned int version: 2;
    /** padding flag */
    unsigned int padding: 1;
    /** varies by packet type */
    unsigned int count:   5;
    /** packet type */
    unsigned int pt:      8;
#else
    /** varies by packet type */
    unsigned int count:   5;
    /** padding flag */
    unsigned int padding: 1;
    /** protocol version */
    unsigned int version: 2;
    /** packet type */
    unsigned int pt:      8;
#endif  
    
    /** packet length in words, w/o this word */
    unsigned int length:  16;
};

/** SDES item */
struct rtcp_sdes_item_t {
    /** type of item (rtcp_sdes_type_t) */
    apr_byte_t type;
    /** length of item (in octets) */
    apr_byte_t length;
    /** text, not null-terminated */
    char       data[1];
};

/** RTCP packet */
struct rtcp_packet_t {
    /** common header */
    rtcp_header_t header;
    /** union of RTCP reports */
    union {
        /** sender report (SR) */
        struct {
            /** sr stat */
            rtcp_sr_stat_t sr_stat;
            /** variable-length list rr stats */
            rtcp_rr_stat_t rr_stat[1];
        } sr;

        /** reception report (RR) */
        struct {
            /** receiver generating this report */
            apr_uint32_t   ssrc;
            /** variable-length list rr stats */
            rtcp_rr_stat_t rr_stat[1];
        } rr;

        /** source description (SDES) */
        struct {
            /** first SSRC/CSRC */
            apr_uint32_t     ssrc;
            /** list of SDES items */
            rtcp_sdes_item_t item[1];
        } sdes;

        /** BYE */
        struct {
            /** list of sources */
            apr_uint32_t ssrc[1];
            /* optional length of reason string (in octets) */
            apr_byte_t   length;
            /* optional reason string, not null-terminated */
            char         data[1];
        } bye;
    } r;
};

/** Initialize RTCP header */
static APR_INLINE void rtcp_header_init(rtcp_header_t *header, rtcp_type_e pt)
{
    header->version = RTP_VERSION;
    header->padding = 0;
    header->count = 0;
    header->pt = pt;
    header->length = 0;
}

static APR_INLINE void rtcp_header_length_set(rtcp_header_t *header, apr_size_t length)
{
    header->length = htons((apr_uint16_t)length / 4 - 1);
}

static APR_INLINE void rtcp_sr_hton(rtcp_sr_stat_t *sr_stat)
{
    sr_stat->ssrc = htonl(sr_stat->ssrc);
    sr_stat->ntp_sec = htonl(sr_stat->ntp_sec);
    sr_stat->ntp_frac = htonl(sr_stat->ntp_frac);
    sr_stat->rtp_ts = htonl(sr_stat->rtp_ts);
    sr_stat->sent_packets = htonl(sr_stat->sent_packets);
    sr_stat->sent_octets = htonl(sr_stat->sent_octets);
}

static APR_INLINE void rtcp_sr_ntoh(rtcp_sr_stat_t *sr_stat)
{
    sr_stat->ssrc = ntohl(sr_stat->ssrc);
    sr_stat->ntp_sec = ntohl(sr_stat->ntp_sec);
    sr_stat->ntp_frac = ntohl(sr_stat->ntp_frac);
    sr_stat->rtp_ts = ntohl(sr_stat->rtp_ts);
    sr_stat->sent_packets = ntohl(sr_stat->sent_packets);
    sr_stat->sent_octets = ntohl(sr_stat->sent_octets);
}

static APR_INLINE void rtcp_rr_hton(rtcp_rr_stat_t *rr_stat)
{
    rr_stat->ssrc = htonl(rr_stat->ssrc);
    rr_stat->last_seq = htonl(rr_stat->last_seq);
    rr_stat->jitter = htonl(rr_stat->jitter);

#if (APR_IS_BIGENDIAN == 0)
    rr_stat->lost = ((rr_stat->lost >> 16) & 0x000000ff) |
                        (rr_stat->lost & 0x0000ff00) |
                            ((rr_stat->lost << 16) & 0x00ff0000);
#endif
}

static APR_INLINE void rtcp_rr_ntoh(rtcp_rr_stat_t *rr_stat)
{
    rr_stat->ssrc = ntohl(rr_stat->ssrc);
    rr_stat->last_seq = ntohl(rr_stat->last_seq);
    rr_stat->jitter = ntohl(rr_stat->jitter);

#if (APR_IS_BIGENDIAN == 0)
    rr_stat->lost = ((rr_stat->lost >> 16) & 0x000000ff) |
                        (rr_stat->lost & 0x0000ff00) |
                            ((rr_stat->lost << 16) & 0x00ff0000);
#endif
}

APT_END_EXTERN_C

#endif /* MPF_RTCP_PACKET_H */