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/* Lossless_UDP.h
*
* An implementation of the Lossless_UDP protocol as seen in http://wiki.tox.im/index.php/Lossless_UDP
*
* Copyright (C) 2013 Tox project All Rights Reserved.
*
* This file is part of Tox.
*
* 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 LOSSLESS_UDP_H
#define LOSSLESS_UDP_H
#include "network.h"
#ifdef __cplusplus
extern "C" {
#endif
/* maximum length of the data in the data packets */
#define MAX_DATA_SIZE 1024
/* maximum data packets in sent and receive queues. */
#define MAX_QUEUE_NUM 16
/* maximum number of data packets in the buffer */
#define BUFFER_PACKET_NUM (16-1)
/* timeout per connection is randomly set between CONNEXION_TIMEOUT and 2*CONNEXION_TIMEOUT */
#define CONNEXION_TIMEOUT 5
/* initial amount of sync/hanshake packets to send per second. */
#define SYNC_RATE 2
/* initial send rate of data. */
#define DATA_SYNC_RATE 30
typedef struct {
uint8_t data[MAX_DATA_SIZE];
uint16_t size;
} Data;
typedef struct {
IP_Port ip_port;
/*
* 0 if connection is dead, 1 if attempting handshake,
* 2 if handshake is done (we start sending SYNC packets)
* 3 if we are sending SYNC packets and can send data
* 4 if the connection has timed out.
*/
uint8_t status;
/*
* 1 or 2 if connection was initiated by someone else, 0 if not.
* 2 if incoming_connection() has not returned it yet, 1 if it has.
*/
uint8_t inbound;
uint16_t SYNC_rate; /* current SYNC packet send rate packets per second. */
uint16_t data_rate; /* current data packet send rate packets per second. */
uint64_t last_SYNC; /* time our last SYNC packet was sent. */
uint64_t last_sent; /* time our last data or handshake packet was sent. */
uint64_t last_recvSYNC; /* time we last received a SYNC packet from the other */
uint64_t last_recvdata; /* time we last received a DATA packet from the other */
uint64_t killat; /* time to kill the connection */
Data sendbuffer[MAX_QUEUE_NUM]; /* packet send buffer. */
Data recvbuffer[MAX_QUEUE_NUM]; /* packet receive buffer. */
uint32_t handshake_id1;
uint32_t handshake_id2;
/* number of data packets received (also used as handshake_id1) */
uint32_t recv_packetnum;
/* number of packets received by the other peer */
uint32_t orecv_packetnum;
/* number of data packets sent */
uint32_t sent_packetnum;
/* number of packets sent by the other peer. */
uint32_t osent_packetnum;
/* number of latest packet written onto the sendbuffer */
uint32_t sendbuff_packetnum;
/* we know all packets before that number were successfully sent */
uint32_t successful_sent;
/* packet number of last packet read with the read_packet function */
uint32_t successful_read;
/* list of currently requested packet numbers(by the other person) */
uint32_t req_packets[BUFFER_PACKET_NUM];
/* total number of currently requested packets(by the other person) */
uint16_t num_req_paquets;
uint8_t recv_counter;
uint8_t send_counter;
uint8_t timeout; /* connection timeout in seconds. */
} Connection;
typedef struct {
Networking_Core *net;
Connection *connections;
uint32_t connections_length; /* Length of connections array */
uint32_t connections_number; /* Number of connections in connections array */
/* table of random numbers used in handshake_id. */
uint32_t randtable[6][256];
} Lossless_UDP;
/*
* Initialize a new connection to ip_port
* Returns an integer corresponding to the connection id.
* Return -1 if it could not initialize the connection.
* Return number if there already was an existing connection to that ip_port.
*/
int new_connection(Lossless_UDP * ludp, IP_Port ip_port);
/*
* Get connection id from IP_Port.
* Return -1 if there are no connections like we are looking for.
* Return id if it found it .
*/
int getconnection_id(Lossless_UDP * ludp, IP_Port ip_port);
/*
* Returns an int corresponding to the next connection in our imcoming connection list
* Return -1 if there are no new incoming connections in the list.
*/
int incoming_connection(Lossless_UDP * ludp);
/*
* Return -1 if it could not kill the connection.
* Return 0 if killed successfully
*/
int kill_connection(Lossless_UDP * ludp, int connection_id);
/*
* Kill connection in seconds seconds.
* Return -1 if it can not kill the connection.
* Return 0 if it will kill it
*/
int kill_connection_in(Lossless_UDP * ludp, int connection_id, uint32_t seconds);
/*
* Returns the ip_port of the corresponding connection.
* Return 0 if there is no such connection.
*/
IP_Port connection_ip(Lossless_UDP * ludp, int connection_id);
/*
* Returns the id of the next packet in the queue
* Return -1 if no packet in queue
*/
char id_packet(Lossless_UDP * ludp, int connection_id);
/*
* Return 0 if there is no received data in the buffer.
* Return length of received packet if successful
*/
int read_packet(Lossless_UDP * ludp, int connection_id, uint8_t *data);
/*
* Return 0 if data could not be put in packet queue
* Return 1 if data was put into the queue
*/
int write_packet(Lossless_UDP * ludp, int connection_id, uint8_t *data, uint32_t length);
/* Returns the number of packets in the queue waiting to be successfully sent. */
uint32_t sendqueue(Lossless_UDP * ludp, int connection_id);
/*
* returns the number of packets in the queue waiting to be successfully
* read with read_packet(...)
*/
uint32_t recvqueue(Lossless_UDP * ludp, int connection_id);
/* Check if connection is connected:
* Return 0 no.
* Return 1 if attempting handshake.
* Return 2 if handshake is done.
* Return 3 if fully connected.
* Return 4 if timed out and wating to be killed.
*/
int is_connected(Lossless_UDP * ludp, int connection_id);
/* Call this function a couple times per second It's the main loop. */
void do_lossless_udp(Lossless_UDP * ludp);
/*
* This function sets up LosslessUDP packet handling.
*/
Lossless_UDP * new_lossless_udp(Networking_Core * net);
void kill_lossless_udp(Lossless_UDP * ludp);
#ifdef __cplusplus
}
#endif
#endif
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