rtp.h

/*
 * rtp.h  --  RTP header file 
 */

/* Modified for use in UC3M lab */

#include "types.h"   /* changed from <sys/types.h> by Akira 12/27/01 */
#include "sysdep.h"

#if 0 /* types.h has a better definition for this. by Akira 12/27/01 */
/*
 * The type definitions below are valid for 32-bit architectures and
 * may have to be adjusted for 16- or 64-bit architectures.
 */
typedef unsigned char  u_int8;
typedef unsigned short u_int16;
typedef unsigned int   u_int32;
typedef          short int16;
#endif

/*
 * System endianness -- determined by autoconf.
 */
#ifdef WORDS_BIGENDIAN
#define RTP_BIG_ENDIAN 1
#else
#define RTP_LITTLE_ENDIAN 1
#endif

/*
 * Current protocol version.
 */
#define RTP_VERSION    2

#define RTP_SEQ_MOD (1<<16)
#define RTP_MAX_SDES 255      /* maximum text length for SDES */

typedef enum {
    RTCP_SR   = 200,
    RTCP_RR   = 201,
    RTCP_SDES = 202,
    RTCP_BYE  = 203,
    RTCP_APP  = 204
} rtcp_type_t;

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_t;

/* ----------------------------------------------------------------------------------------------------- */
/*
 * RTP data header
 */
typedef struct {
#if RTP_BIG_ENDIAN
    unsigned int version:2;   /* protocol version */
    unsigned int p:1;         /* padding flag */
    unsigned int x:1;         /* header extension flag */
    unsigned int cc:4;        /* CSRC count */
    unsigned int m:1;         /* marker bit */
    unsigned int pt:7;        /* payload type */
#elif RTP_LITTLE_ENDIAN
    unsigned int cc:4;        /* CSRC count */
    unsigned int x:1;         /* header extension flag */
    unsigned int p:1;         /* padding flag */
    unsigned int version:2;   /* protocol version */
    unsigned int pt:7;        /* payload type */
    unsigned int m:1;         /* marker bit */
#else
#error Define one of RTP_LITTLE_ENDIAN or RTP_BIG_ENDIAN
#endif
    unsigned int seq:16;      /* sequence number */
    u_int32 ts;               /* timestamp */
    u_int32 ssrc;             /* synchronization source */
    /* UC3M: in the example of the RFC, here appears a csrc field. Our application setting does not require CSRCs so the best option is to remove them */
} rtp_hdr_t;



/* UC3M : next part is RTCP-specific */

/* ----------------------------------------------------------------------------------------------------- */
/*
 * RTCP common header word
 */
typedef struct {
#if RTP_BIG_ENDIAN
    unsigned int version:2;   /* protocol version */
    unsigned int p:1;         /* padding flag */
    unsigned int count:5;     /* varies by packet type */
#elif RTP_LITTLE_ENDIAN
    unsigned int count:5;     /* varies by packet type */
    unsigned int p:1;         /* padding flag */
    unsigned int version:2;   /* protocol version */
#else
#error Define one of RTP_LITTLE_ENDIAN or RTP_BIG_ENDIAN
#endif
    unsigned int pt:8;        /* RTCP packet type */
    unsigned int length:16;   /* pkt len in words, w/o this word */
} rtcp_common_t;

/*
 * Big-endian mask for version, padding bit and packet type pair
 * XXX?
 */
#define RTCP_VALID_MASK (0xc000 | 0x2000 | 0xfe)
#define RTCP_VALID_VALUE ((RTP_VERSION << 14) | RTCP_SR)

/*
 * Reception report block
 */
typedef struct {
    u_int32 ssrc;             /* data source being reported */
    unsigned int fraction:8;  /* fraction lost since last SR/RR */
    int lost:24;              /* cumul. no. pkts lost (signed!) */
    u_int32 last_seq;         /* extended last seq. no. received */
    u_int32 jitter;           /* interarrival jitter */
    u_int32 lsr;              /* last SR packet from this source */
    u_int32 dlsr;             /* delay since last SR packet */
} rtcp_rr_t;

/*
 * SDES item
 */
typedef struct {
    u_int8 type;              /* type of item (rtcp_sdes_type_t) */
    u_int8 length;            /* length of item (in octets) */
    char data[1];             /* text, not null-terminated */
} rtcp_sdes_item_t;


/*
 * One RTCP packet
 */
typedef struct {
    rtcp_common_t common;     /* common header */
    union {
        /* sender report (SR) */
        struct {
            u_int32 ssrc;     /* sender generating this report */
            u_int32 ntp_sec;  /* NTP timestamp */
            u_int32 ntp_frac;
            u_int32 rtp_ts;   /* RTP timestamp */
            u_int32 psent;    /* packets sent */
            u_int32 osent;    /* octets sent */ 
            rtcp_rr_t rr[1];  /* variable-length list */
            			/* UC3M: this is a generic definition. Note that in a typical application this is not known in compilation time, but depends on the number of peers you have. Real applications may not be able to use static declarations -such as this- to fill this part of the information.
            			Fortunately, in our specific case we know from the very specification of the application the number of peers we are having: 1.
            			So this definition is fine for you */
        } sr;

        /* reception report (RR) */
        struct {
            u_int32 ssrc;     /* receiver generating this report */
            rtcp_rr_t rr[1];  /* variable-length list */
        } rr;

        /* source description (SDES) */
        struct rtcp_sdes {
            u_int32 src;      /* first SSRC/CSRC */
            rtcp_sdes_item_t item[1]; /* list of SDES items */
            			/* UC3M: this is a generic definition. This is similar to case stated for the Sender Report. 
            			You should put here the exact number of SDES items  you plan to use,... IN THIS CASE YOU WANT TO USE A DIFFERENT NUMBER, SO PLEASE CHANGE THIS VALUE */
        } sdes;

        /* BYE */
        struct {
            u_int32 src[1];   /* list of sources */
            		/* UC3M: similar consideration to the previous SR and SDES case */
            		/* UC3M: we can't express trailing text in this way. If you are using the same message all the time, count the characters, and define a char text[CHAR_NUM+1] field - remember always to finish a string with '\0' */
        } bye;
    } r;
} rtcp_t;

typedef struct rtcp_sdes rtcp_sdes_t;

/*
 * Per-source state information
 */
/* UC3M: this is the structure in which you introduce the information regarding the peer sending RTCP info to you */
#define MAX_LEN_SDES_ITEM 128

typedef struct {
  u_int16 max_seq;        /* highest seq. number seen */
  u_int32 cycles;         /* shifted count of seq. number cycles */
  u_int32 base_seq;       /* base seq number */
  u_int32 bad_seq;        /* last 'bad' seq number + 1 */
  u_int32 probation;      /* sequ. packets till source is valid */
  u_int32 received;       /* packets received */
  u_int32 expected_prior; /* packet expected at last interval */
  u_int32 received_prior; /* packet received at last interval */
  u_int32 transit;        /* relative trans time for prev pkt */
  u_int32 jitter;         /* estimated jitter */
  /* ... */
  /* UC3M specific definitions */
  char CNAME[MAX_LEN_SDES_ITEM]; /* stores the last CNAME value advertised by the peer. Must be a '\0' terminated string. */
  char TOOL[MAX_LEN_SDES_ITEM]; /* stores the last TOOL value advertised by the peer. Must be a '\0' terminated string. */
} source;