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/*
* Copyright © 2016-2018 The TokTok team.
* Copyright © 2013-2015 Tox project.
*
* This file is part of Tox, the free peer to peer instant messenger.
*
* Tox 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.
*
* Tox 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 Tox. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef RTP_H
#define RTP_H
#include "bwcontroller.h"
#include "../toxcore/Messenger.h"
#include "../toxcore/logger.h"
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* RTPHeader serialised size in bytes.
*/
#define RTP_HEADER_SIZE 80
/**
* Number of 32 bit padding fields between \ref RTPHeader::offset_lower and
* everything before it.
*/
#define RTP_PADDING_FIELDS 11
/**
* Payload type identifier. Also used as rtp callback prefix.
*/
enum {
rtp_TypeAudio = 192,
rtp_TypeVideo = 193,
};
/**
* A bit mask (up to 64 bits) specifying features of the current frame affecting
* the behaviour of the decoder.
*/
enum RTPFlags {
/**
* Support frames larger than 64KiB. The full 32 bit length and offset are
* set in \ref RTPHeader::data_length_full and \ref RTPHeader::offset_full.
*/
RTP_LARGE_FRAME = 1 << 0,
/**
* Whether the packet is part of a key frame.
*/
RTP_KEY_FRAME = 1 << 1,
};
struct RTPHeader {
/* Standard RTP header */
unsigned protocol_version: 2; /* Version has only 2 bits! */
unsigned pe: 1; /* Padding */
unsigned xe: 1; /* Extra header */
unsigned cc: 4; /* Contributing sources count */
unsigned ma: 1; /* Marker */
unsigned pt: 7; /* Payload type */
uint16_t sequnum;
uint32_t timestamp;
uint32_t ssrc;
/* Non-standard Tox-specific fields */
/**
* Bit mask of \ref RTPFlags setting features of the current frame.
*/
uint64_t flags;
/**
* The full 32 bit data offset of the current data chunk. The \ref
* offset_lower data member contains the lower 16 bits of this value. For
* frames smaller than 64KiB, \ref offset_full and \ref offset_lower are
* equal.
*/
uint32_t offset_full;
/**
* The full 32 bit payload length without header and packet id.
*/
uint32_t data_length_full;
/**
* Only the receiver uses this field (why do we have this?).
*/
uint32_t received_length_full;
/**
* Data offset of the current part (lower bits).
*/
uint16_t offset_lower;
/**
* Total message length (lower bits).
*/
uint16_t data_length_lower;
};
struct RTPMessage {
uint16_t len;
struct RTPHeader header;
uint8_t data[];
};
/**
* RTP control session.
*/
typedef struct {
uint8_t payload_type;
uint16_t sequnum; /* Sending sequence number */
uint16_t rsequnum; /* Receiving sequence number */
uint32_t rtimestamp;
uint32_t ssrc;
struct RTPMessage *mp; /* Expected parted message */
Messenger *m;
uint32_t friend_number;
BWController *bwc;
void *cs;
int (*mcb)(void *, struct RTPMessage *msg);
} RTPSession;
/**
* Serialise an RTPHeader to bytes to be sent over the network.
*
* @param rdata A byte array of length RTP_HEADER_SIZE. Does not need to be
* initialised. All RTP_HEADER_SIZE bytes will be initialised after a call
* to this function.
* @param header The RTPHeader to serialise.
*/
size_t rtp_header_pack(uint8_t *rdata, const struct RTPHeader *header);
/**
* Deserialise an RTPHeader from bytes received over the network.
*
* @param data A byte array of length RTP_HEADER_SIZE.
* @param header The RTPHeader to write the unpacked values to.
*/
size_t rtp_header_unpack(const uint8_t *data, struct RTPHeader *header);
RTPSession *rtp_new(int payload_type, Messenger *m, uint32_t friendnumber,
BWController *bwc, void *cs,
int (*mcb)(void *, struct RTPMessage *));
void rtp_kill(RTPSession *session);
int rtp_allow_receiving(RTPSession *session);
int rtp_stop_receiving(RTPSession *session);
int rtp_send_data(RTPSession *session, const uint8_t *data, uint16_t length, Logger *log);
#ifdef __cplusplus
} // extern "C"
#endif
#endif /* RTP_H */
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