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toxcore/core/Lossless_UDP.c
Michael Rose 3868a5326c refactoring packet IDs
2013-08-21 09:55:43 +02:00

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/* Lossless_UDP.c
*
* 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/>.
*
*/
/*
* TODO: clean this file a bit.
* There are a couple of useless variables to get rid of.
*/
#include "Lossless_UDP.h"
/* Functions */
/*
* 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)
{
uint32_t i;
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].ip_port.ip.i == ip_port.ip.i &&
ludp->connections[i].ip_port.port == ip_port.port &&
ludp->connections[i].status > 0)
return i;
}
return -1;
}
/*
* Generate a handshake_id which depends on the ip_port.
* This function will always give one unique handshake_id per ip_port.
*
* TODO: make this better
*/
static uint32_t handshake_id(Lossless_UDP *ludp, IP_Port source)
{
uint32_t id = 0, i;
for (i = 0; i < 6; ++i) {
if (ludp->randtable[i][((uint8_t *)&source)[i]] == 0)
ludp->randtable[i][((uint8_t *)&source)[i]] = random_int();
id ^= ludp->randtable[i][((uint8_t *)&source)[i]];
}
if (id == 0) /* id can't be zero */
id = 1;
return id;
}
/*
* Change the hanshake id associated with that ip_port
*
* TODO: make this better
*/
static void change_handshake(Lossless_UDP *ludp, IP_Port source)
{
uint8_t rand = random_int() % 4;
ludp->randtable[rand][((uint8_t *)&source)[rand]] = random_int();
}
/*
* Initialize a new connection to ip_port
* Returns an integer corresponding to the connection idt
* Return -1 if it could not initialize the connectiont
* If there already was an existing connection to that ip_port return its number.
*/
int new_connection(Lossless_UDP *ludp, IP_Port ip_port)
{
int connect = getconnection_id(ludp, ip_port);
if (connect != -1)
return connect;
if (ludp->connections_number == ludp->connections_length) {
Connection *temp;
temp = realloc(ludp->connections, sizeof(Connection) * (ludp->connections_length + 1));
if (temp == NULL)
return -1;
memset(&temp[ludp->connections_length], 0, sizeof(Connection));
++ludp->connections_length;
ludp->connections = temp;
}
uint32_t i;
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].status == 0) {
memset(&ludp->connections[i], 0, sizeof(Connection));
uint32_t handshake_id1 = handshake_id(ludp, ip_port);
ludp->connections[i] = (Connection) {
.ip_port = ip_port,
.status = 1,
.inbound = 0,
.handshake_id1 = handshake_id1,
.sent_packetnum = handshake_id1,
.sendbuff_packetnum = handshake_id1,
.successful_sent = handshake_id1,
.SYNC_rate = SYNC_RATE,
.data_rate = DATA_SYNC_RATE,
.last_recvSYNC = current_time(),
.last_sent = current_time(),
.killat = ~0,
.send_counter = 0,
/* add randomness to timeout to prevent connections getting stuck in a loop. */
.timeout = CONNEXION_TIMEOUT + rand() % CONNEXION_TIMEOUT
};
++ludp->connections_number;
return i;
}
}
return -1;
}
/*
* Initialize a new inbound connection from ip_port
* Returns an integer corresponding to the connection id.
* Return -1 if it could not initialize the connection.
*/
static int new_inconnection(Lossless_UDP *ludp, IP_Port ip_port)
{
if (getconnection_id(ludp, ip_port) != -1)
return -1;
if (ludp->connections_number == ludp->connections_length) {
Connection *temp;
temp = realloc(ludp->connections, sizeof(Connection) * (ludp->connections_length + 1));
if (temp == NULL)
return -1;
memset(&temp[ludp->connections_length], 0, sizeof(Connection));
++ludp->connections_length;
ludp->connections = temp;
}
uint32_t i;
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].status == 0) {
memset(&ludp->connections[i], 0, sizeof(Connection));
uint64_t timeout = CONNEXION_TIMEOUT + rand() % CONNEXION_TIMEOUT;
ludp->connections[i] = (Connection) {
.ip_port = ip_port,
.status = 2,
.inbound = 2,
.SYNC_rate = SYNC_RATE,
.data_rate = DATA_SYNC_RATE,
.last_recvSYNC = current_time(),
.last_sent = current_time(),
.send_counter = 127,
/* add randomness to timeout to prevent connections getting stuck in a loop. */
.timeout = timeout,
/* if this connection isn't handled within the timeout kill it. */
.killat = current_time() + 1000000UL * timeout
};
++ludp->connections_number;
return i;
}
}
return -1;
}
/*
* Returns an integer corresponding to the next connection in our incoming connection list.
* Return -1 if there are no new incoming connections in the list.
*/
int incoming_connection(Lossless_UDP *ludp)
{
uint32_t i;
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].inbound == 2) {
ludp->connections[i].inbound = 1;
return i;
}
}
return -1;
}
/* Try to free some memory from the connections array. */
static void free_connections(Lossless_UDP *ludp)
{
uint32_t i;
for (i = ludp->connections_length; i != 0; --i)
if (ludp->connections[i - 1].status != 0)
break;
if (ludp->connections_length == i)
return;
if (i == 0) {
free(ludp->connections);
ludp->connections = NULL;
ludp->connections_length = i;
return;
}
Connection *temp;
temp = realloc(ludp->connections, sizeof(Connection) * i);
if (temp == NULL && i != 0)
return;
ludp->connections = temp;
ludp->connections_length = i;
}
/*
* Return -1 if it could not kill the connection.
* Return 0 if killed successfully
*/
int kill_connection(Lossless_UDP *ludp, int connection_id)
{
if (connection_id >= 0 && connection_id < ludp->connections_length) {
if (ludp->connections[connection_id].status > 0) {
ludp->connections[connection_id].status = 0;
change_handshake(ludp, ludp->connections[connection_id].ip_port);
--ludp->connections_number;
free_connections(ludp);
return 0;
}
}
return -1;
}
/*
* Kill connection in 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)
{
if (connection_id >= 0 && connection_id < ludp->connections_length) {
if (ludp->connections[connection_id].status > 0) {
ludp->connections[connection_id].killat = current_time() + 1000000UL * seconds;
return 0;
}
}
return -1;
}
/*
* 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 waiting to be killed.
*/
int is_connected(Lossless_UDP *ludp, int connection_id)
{
if (connection_id >= 0 && connection_id < ludp->connections_length)
return ludp->connections[connection_id].status;
return 0;
}
/* returns the ip_port of the corresponding connection. */
IP_Port connection_ip(Lossless_UDP *ludp, int connection_id)
{
if (connection_id >= 0 && connection_id < ludp->connections_length)
return ludp->connections[connection_id].ip_port;
IP_Port zero = {{{0}}, 0};
return zero;
}
/* returns the number of packets in the queue waiting to be successfully sent. */
uint32_t sendqueue(Lossless_UDP *ludp, int connection_id)
{
if (connection_id < 0 || connection_id >= ludp->connections_length)
return 0;
return ludp->connections[connection_id].sendbuff_packetnum - ludp->connections[connection_id].successful_sent;
}
/* 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)
{
if (connection_id < 0 || connection_id >= ludp->connections_length)
return 0;
return ludp->connections[connection_id].recv_packetnum - ludp->connections[connection_id].successful_read;
}
/* 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)
{
if (connection_id < 0 || connection_id >= ludp->connections_length)
return -1;
if (recvqueue(ludp, connection_id) != 0 && ludp->connections[connection_id].status != 0)
return ludp->connections[connection_id].recvbuffer[ludp->connections[connection_id].successful_read %
MAX_QUEUE_NUM].data[0];
return -1;
}
/* 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)
{
if (recvqueue(ludp, connection_id) != 0) {
uint16_t index = ludp->connections[connection_id].successful_read % MAX_QUEUE_NUM;
uint16_t size = ludp->connections[connection_id].recvbuffer[index].size;
memcpy(data, ludp->connections[connection_id].recvbuffer[index].data, size);
++ludp->connections[connection_id].successful_read;
ludp->connections[connection_id].recvbuffer[index].size = 0;
return size;
}
return 0;
}
/*
* 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)
{
if (length > MAX_DATA_SIZE || length == 0)
return 0;
if (sendqueue(ludp, connection_id) < BUFFER_PACKET_NUM) {
uint32_t index = ludp->connections[connection_id].sendbuff_packetnum % MAX_QUEUE_NUM;
memcpy(ludp->connections[connection_id].sendbuffer[index].data, data, length);
ludp->connections[connection_id].sendbuffer[index].size = length;
ludp->connections[connection_id].sendbuff_packetnum++;
return 1;
}
return 0;
}
/* put the packet numbers the we are missing in requested and return the number */
uint32_t missing_packets(Lossless_UDP *ludp, int connection_id, uint32_t *requested)
{
uint32_t number = 0;
uint32_t i;
uint32_t temp;
/* don't request packets if the buffer is full. */
if (recvqueue(ludp, connection_id) >= (BUFFER_PACKET_NUM - 1))
return 0;
for (i = ludp->connections[connection_id].recv_packetnum; i != ludp->connections[connection_id].osent_packetnum; i++) {
if (ludp->connections[connection_id].recvbuffer[i % MAX_QUEUE_NUM].size == 0) {
temp = htonl(i);
memcpy(requested + number, &temp, 4);
++number;
}
}
if (number == 0)
ludp->connections[connection_id].recv_packetnum = ludp->connections[connection_id].osent_packetnum;
return number;
}
/*
* BEGIN Packet sending functions
* One per packet type.
* see http://wiki.tox.im/index.php/Lossless_UDP for more information.
*/
static int send_handshake(Lossless_UDP *ludp, IP_Port ip_port, uint32_t handshake_id1, uint32_t handshake_id2)
{
uint8_t packet[1 + 4 + 4];
uint32_t temp;
packet[0] = NET_PACKET_HANDSHAKE;
temp = htonl(handshake_id1);
memcpy(packet + 1, &temp, 4);
temp = htonl(handshake_id2);
memcpy(packet + 5, &temp, 4);
return sendpacket(ludp->net->sock, ip_port, packet, sizeof(packet));
}
static int send_SYNC(Lossless_UDP *ludp, uint32_t connection_id)
{
uint8_t packet[(BUFFER_PACKET_NUM * 4 + 4 + 4 + 2)];
uint16_t index = 0;
IP_Port ip_port = ludp->connections[connection_id].ip_port;
uint8_t counter = ludp->connections[connection_id].send_counter;
uint32_t recv_packetnum = htonl(ludp->connections[connection_id].recv_packetnum);
uint32_t sent_packetnum = htonl(ludp->connections[connection_id].sent_packetnum);
uint32_t requested[BUFFER_PACKET_NUM];
uint32_t number = missing_packets(ludp, connection_id, requested);
packet[0] = NET_PACKET_SYNC;
index += 1;
memcpy(packet + index, &counter, 1);
index += 1;
memcpy(packet + index, &recv_packetnum, 4);
index += 4;
memcpy(packet + index, &sent_packetnum, 4);
index += 4;
memcpy(packet + index, requested, 4 * number);
return sendpacket(ludp->net->sock, ip_port, packet, (number * 4 + 4 + 4 + 2));
}
static int send_data_packet(Lossless_UDP *ludp, uint32_t connection_id, uint32_t packet_num)
{
uint32_t index = packet_num % MAX_QUEUE_NUM;
uint32_t temp;
uint8_t packet[1 + 4 + MAX_DATA_SIZE];
packet[0] = NET_PACKET_DATA;
temp = htonl(packet_num);
memcpy(packet + 1, &temp, 4);
memcpy(packet + 5, ludp->connections[connection_id].sendbuffer[index].data,
ludp->connections[connection_id].sendbuffer[index].size);
return sendpacket(ludp->net->sock, ludp->connections[connection_id].ip_port, packet,
1 + 4 + ludp->connections[connection_id].sendbuffer[index].size);
}
/* sends 1 data packet */
static int send_DATA(Lossless_UDP *ludp, uint32_t connection_id)
{
int ret;
uint32_t buffer[BUFFER_PACKET_NUM];
if (ludp->connections[connection_id].num_req_paquets > 0) {
ret = send_data_packet(ludp, connection_id, ludp->connections[connection_id].req_packets[0]);
ludp->connections[connection_id].num_req_paquets--;
memcpy(buffer, ludp->connections[connection_id].req_packets + 1, ludp->connections[connection_id].num_req_paquets * 4);
memcpy(ludp->connections[connection_id].req_packets, buffer, ludp->connections[connection_id].num_req_paquets * 4);
return ret;
}
if (ludp->connections[connection_id].sendbuff_packetnum != ludp->connections[connection_id].sent_packetnum) {
ret = send_data_packet(ludp, connection_id, ludp->connections[connection_id].sent_packetnum);
ludp->connections[connection_id].sent_packetnum++;
return ret;
}
return 0;
}
/*
* END of packet sending functions
*
*
* BEGIN Packet handling functions
* One to handle each type of packets we receive
*/
/* Return 0 if handled correctly, 1 if packet is bad. */
static int handle_handshake(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
Lossless_UDP *ludp = object;
if (length != (1 + 4 + 4))
return 1;
uint32_t temp;
uint32_t handshake_id1, handshake_id2;
int connection = getconnection_id(ludp, source);
memcpy(&temp, packet + 1, 4);
handshake_id1 = ntohl(temp);
memcpy(&temp, packet + 5, 4);
handshake_id2 = ntohl(temp);
if (handshake_id2 == 0 && is_connected(ludp, connection) < 3) {
send_handshake(ludp, source, handshake_id(ludp, source), handshake_id1);
return 0;
}
if (is_connected(ludp, connection) != 1)
return 1;
/* if handshake_id2 is what we sent previously as handshake_id1 */
if (handshake_id2 == ludp->connections[connection].handshake_id1) {
ludp->connections[connection].status = 2;
/* NOTE: is this necessary?
ludp->connections[connection].handshake_id2 = handshake_id1; */
ludp->connections[connection].orecv_packetnum = handshake_id2;
ludp->connections[connection].osent_packetnum = handshake_id1;
ludp->connections[connection].recv_packetnum = handshake_id1;
ludp->connections[connection].successful_read = handshake_id1;
}
return 0;
}
/* returns 1 if sync packet is valid 0 if not. */
static int SYNC_valid(uint32_t length)
{
if (length < 4 + 4 + 2)
return 0;
if (length > (BUFFER_PACKET_NUM * 4 + 4 + 4 + 2) ||
((length - 4 - 4 - 2) % 4) != 0)
return 0;
return 1;
}
/* case 1 in handle_SYNC: */
static int handle_SYNC1(Lossless_UDP *ludp, IP_Port source, uint32_t recv_packetnum, uint32_t sent_packetnum)
{
if (handshake_id(ludp, source) == recv_packetnum) {
int x = new_inconnection(ludp, source);
if (x != -1) {
ludp->connections[x].orecv_packetnum = recv_packetnum;
ludp->connections[x].sent_packetnum = recv_packetnum;
ludp->connections[x].sendbuff_packetnum = recv_packetnum;
ludp->connections[x].successful_sent = recv_packetnum;
ludp->connections[x].osent_packetnum = sent_packetnum;
ludp->connections[x].recv_packetnum = sent_packetnum;
ludp->connections[x].successful_read = sent_packetnum;
return x;
}
}
return -1;
}
/* case 2 in handle_SYNC: */
static int handle_SYNC2(Lossless_UDP *ludp, int connection_id, uint8_t counter, uint32_t recv_packetnum,
uint32_t sent_packetnum)
{
if (recv_packetnum == ludp->connections[connection_id].orecv_packetnum) {
/* && sent_packetnum == ludp->connections[connection_id].osent_packetnum) */
ludp->connections[connection_id].status = 3;
ludp->connections[connection_id].recv_counter = counter;
++ludp->connections[connection_id].send_counter;
send_SYNC(ludp, connection_id);
return 0;
}
return 1;
}
/* case 3 in handle_SYNC: */
static int handle_SYNC3(Lossless_UDP *ludp, int connection_id, uint8_t counter, uint32_t recv_packetnum,
uint32_t sent_packetnum,
uint32_t *req_packets,
uint16_t number)
{
uint8_t comp_counter = (counter - ludp->connections[connection_id].recv_counter );
uint32_t i, temp;
/* uint32_t comp_1 = (recv_packetnum - ludp->connections[connection_id].successful_sent);
uint32_t comp_2 = (sent_packetnum - ludp->connections[connection_id].successful_read); */
uint32_t comp_1 = (recv_packetnum - ludp->connections[connection_id].orecv_packetnum);
uint32_t comp_2 = (sent_packetnum - ludp->connections[connection_id].osent_packetnum);
/* packet valid */
if (comp_1 <= BUFFER_PACKET_NUM &&
comp_2 <= BUFFER_PACKET_NUM &&
comp_counter < 10 && comp_counter != 0) {
ludp->connections[connection_id].orecv_packetnum = recv_packetnum;
ludp->connections[connection_id].osent_packetnum = sent_packetnum;
ludp->connections[connection_id].successful_sent = recv_packetnum;
ludp->connections[connection_id].last_recvSYNC = current_time();
ludp->connections[connection_id].recv_counter = counter;
++ludp->connections[connection_id].send_counter;
for (i = 0; i < number; ++i) {
temp = ntohl(req_packets[i]);
memcpy(ludp->connections[connection_id].req_packets + i, &temp, 4 * number);
}
ludp->connections[connection_id].num_req_paquets = number;
return 0;
}
return 1;
}
static int handle_SYNC(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
Lossless_UDP *ludp = object;
if (!SYNC_valid(length))
return 1;
int connection = getconnection_id(ludp, source);
uint8_t counter;
uint32_t temp;
uint32_t recv_packetnum, sent_packetnum;
uint32_t req_packets[BUFFER_PACKET_NUM];
uint16_t number = (length - 4 - 4 - 2) / 4;
memcpy(&counter, packet + 1, 1);
memcpy(&temp, packet + 2, 4);
recv_packetnum = ntohl(temp);
memcpy(&temp, packet + 6, 4);
sent_packetnum = ntohl(temp);
if (number != 0)
memcpy(req_packets, packet + 10, 4 * number);
if (connection == -1)
return handle_SYNC1(ludp, source, recv_packetnum, sent_packetnum);
if (ludp->connections[connection].status == 2)
return handle_SYNC2(ludp, connection, counter,
recv_packetnum, sent_packetnum);
if (ludp->connections[connection].status == 3)
return handle_SYNC3(ludp, connection, counter, recv_packetnum,
sent_packetnum, req_packets, number);
return 0;
}
/*
* Add a packet to the received buffer and set the recv_packetnum of the
* connection to its proper value. Return 1 if data was too big, 0 if not.
*/
static int add_recv(Lossless_UDP *ludp, int connection_id, uint32_t data_num, uint8_t *data, uint16_t size)
{
if (size > MAX_DATA_SIZE)
return 1;
uint32_t i;
uint32_t maxnum = ludp->connections[connection_id].successful_read + BUFFER_PACKET_NUM;
uint32_t sent_packet = data_num - ludp->connections[connection_id].osent_packetnum;
for (i = ludp->connections[connection_id].recv_packetnum; i != maxnum; ++i) {
if (i == data_num) {
memcpy(ludp->connections[connection_id].recvbuffer[i % MAX_QUEUE_NUM].data, data, size);
ludp->connections[connection_id].recvbuffer[i % MAX_QUEUE_NUM].size = size;
ludp->connections[connection_id].last_recvdata = current_time();
if (sent_packet < BUFFER_PACKET_NUM) {
ludp->connections[connection_id].osent_packetnum = data_num;
}
break;
}
}
for (i = ludp->connections[connection_id].recv_packetnum; i != maxnum; ++i) {
if (ludp->connections[connection_id].recvbuffer[i % MAX_QUEUE_NUM].size != 0)
ludp->connections[connection_id].recv_packetnum = i;
else
break;
}
return 0;
}
static int handle_data(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
Lossless_UDP *ludp = object;
int connection = getconnection_id(ludp, source);
if (connection == -1)
return 1;
/* Drop the data packet if connection is not connected. */
if (ludp->connections[connection].status != 3)
return 1;
if (length > 1 + 4 + MAX_DATA_SIZE || length < 1 + 4 + 1)
return 1;
uint32_t temp;
uint32_t number;
uint16_t size = length - 1 - 4;
memcpy(&temp, packet + 1, 4);
number = ntohl(temp);
return add_recv(ludp, connection, number, packet + 5, size);
}
/*
* END of packet handling functions
*/
Lossless_UDP *new_lossless_udp(Networking_Core *net)
{
if (net == NULL)
return NULL;
Lossless_UDP *temp = calloc(1, sizeof(Lossless_UDP));
if (temp == NULL)
return NULL;
temp->net = net;
networking_registerhandler(net, NET_PACKET_HANDSHAKE, &handle_handshake, temp);
networking_registerhandler(net, NET_PACKET_SYNC, &handle_SYNC, temp);
networking_registerhandler(net, NET_PACKET_DATA, &handle_data, temp);
return temp;
}
/*
* Send handshake requests
* handshake packets are sent at the same rate as SYNC packets
*/
static void do_new(Lossless_UDP *ludp)
{
uint32_t i;
uint64_t temp_time = current_time();
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].status == 1)
if ((ludp->connections[i].last_sent + (1000000UL / ludp->connections[i].SYNC_rate)) <= temp_time) {
send_handshake(ludp, ludp->connections[i].ip_port, ludp->connections[i].handshake_id1, 0);
ludp->connections[i].last_sent = temp_time;
}
/* kill all timed out connections */
if (ludp->connections[i].status > 0 &&
(ludp->connections[i].last_recvSYNC + ludp->connections[i].timeout * 1000000UL) < temp_time &&
ludp->connections[i].status != 4) {
ludp->connections[i].status = 4;
/* kill_connection(i); */
}
if (ludp->connections[i].status > 0 && ludp->connections[i].killat < temp_time)
kill_connection(ludp, i);
}
}
static void do_SYNC(Lossless_UDP *ludp)
{
uint32_t i;
uint64_t temp_time = current_time();
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].status == 2 || ludp->connections[i].status == 3)
if ((ludp->connections[i].last_SYNC + (1000000UL / ludp->connections[i].SYNC_rate)) <= temp_time) {
send_SYNC(ludp, i);
ludp->connections[i].last_SYNC = temp_time;
}
}
}
static void do_data(Lossless_UDP *ludp)
{
uint32_t i;
uint64_t j;
uint64_t temp_time = current_time();
for (i = 0; i < ludp->connections_length; ++i)
if (ludp->connections[i].status == 3 && sendqueue(ludp, i) != 0)
if ((ludp->connections[i].last_sent + (1000000UL / ludp->connections[i].data_rate)) <= temp_time) {
for (j = ludp->connections[i].last_sent; j < temp_time; j += (1000000UL / ludp->connections[i].data_rate))
send_DATA(ludp, i);
ludp->connections[i].last_sent = temp_time;
}
}
#define MAX_SYNC_RATE 10
/*
* Automatically adjusts send rates of packets for optimal transmission.
*
* TODO: flow control.
*/
static void adjust_rates(Lossless_UDP *ludp)
{
uint32_t i;
uint64_t temp_time = current_time();
for (i = 0; i < ludp->connections_length; ++i) {
if (ludp->connections[i].status == 1 || ludp->connections[i].status == 2)
ludp->connections[i].SYNC_rate = MAX_SYNC_RATE;
if (ludp->connections[i].status == 3) {
if (sendqueue(ludp, i) != 0) {
ludp->connections[i].data_rate = (BUFFER_PACKET_NUM - ludp->connections[i].num_req_paquets) * MAX_SYNC_RATE;
ludp->connections[i].SYNC_rate = MAX_SYNC_RATE;
} else if (ludp->connections[i].last_recvdata + 1000000UL > temp_time)
ludp->connections[i].SYNC_rate = MAX_SYNC_RATE;
else
ludp->connections[i].SYNC_rate = SYNC_RATE;
}
}
}
/* Call this function a couple times per second It's the main loop. */
void do_lossless_udp(Lossless_UDP *ludp)
{
do_new(ludp);
do_SYNC(ludp);
do_data(ludp);
adjust_rates(ludp);
}
void kill_lossless_udp(Lossless_UDP *ludp)
{
free(ludp->connections);
free(ludp);
}
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