/* 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 . * */ /* * TODO: clean this file a bit. * There are a couple of useless variables to get rid of. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "Lossless_UDP.h" #define LUDP_CONNECTION_OUTBOUND 0 #define LUDP_CONNECTION_INBOUND_HANDLED 1 #define LUDP_CONNECTION_INBOUND 2 /* 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) { tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status != LUDP_NO_CONNECTION && ipport_equal(&tmp->ip_port, &ip_port)) { return tmp_i; } } return -1; } /* Resize a queue * return length of queue on success. * return ~0 on failure. */ uint32_t resize_queue(Data **buffer, uint32_t length, uint32_t new_length, uint32_t min_packetnum, uint32_t max_packetnum) { if (MAX_QUEUE_NUM < new_length) new_length = MAX_QUEUE_NUM; if (max_packetnum - min_packetnum > new_length) return ~0; if (length == new_length) return new_length; Data *temp = calloc(1, sizeof(Data) * new_length); if (temp == NULL) return ~0; if (*buffer == NULL) { *buffer = temp; return new_length; } uint32_t i; for (i = min_packetnum; i != max_packetnum; ++i) memcpy(temp + (i % new_length), *buffer + (i % length), sizeof(Data)); free(*buffer); *buffer = temp; return new_length; } /* * 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 randtable_initget(Lossless_UDP *ludp, uint32_t index, uint8_t value) { if (ludp->randtable[index][value] == 0) ludp->randtable[index][value] = random_int(); return ludp->randtable[index][value]; } static uint32_t handshake_id(Lossless_UDP *ludp, IP_Port source) { uint32_t id = 0, i = 0; uint8_t *uint8; uint8 = (uint8_t *)&source.port; id ^= randtable_initget(ludp, i, *uint8); i++, uint8++; id ^= randtable_initget(ludp, i, *uint8); i++; if (source.ip.family == AF_INET) { int k; for (k = 0; k < 4; k++) { id ^= randtable_initget(ludp, i++, source.ip.ip4.uint8[k]); } } if (source.ip.family == AF_INET6) { int k; for (k = 0; k < 16; k++) { id ^= randtable_initget(ludp, i++, source.ip.ip6.uint8[k]); } } /* id can't be zero. */ if (id == 0) id = 1; return id; } /* * Change the handshake id associated with that ip_port. * * TODO: Make this better */ static void change_handshake(Lossless_UDP *ludp, IP_Port source) { uint8_t rand; if (source.ip.family == AF_INET) { rand = random_int() % 4; } else if (source.ip.family == AF_INET6) { rand = random_int() % 16; } else { return; } /* Forced to be more robust against strange definitions of sa_family_t */ ludp->randtable[2 + rand][((uint8_t *)&source.ip.ip6)[rand]] = random_int(); } /* * Initialize a new connection to ip_port * * return an integer corresponding to the connection id. * 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 connection_id = getconnection_id(ludp, ip_port); if (connection_id != -1) { confirm_connection(ludp, connection_id); return connection_id; } tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_NO_CONNECTION) { connection_id = tmp_i; break; } } if (connection_id == -1) { if (tox_array_push_ptr(&ludp->connections, 0) == 0) return -1; connection_id = ludp->connections.len - 1; } Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); memset(connection, 0, sizeof(Connection)); uint32_t handshake_id1 = handshake_id(ludp, ip_port); /* Add randomness to timeout to prevent connections getting stuck in a loop. */ uint8_t timeout = CONNECTION_TIMEOUT + rand() % CONNECTION_TIMEOUT; *connection = (Connection) { .ip_port = ip_port, .status = LUDP_HANDSHAKE_SENDING, .inbound = LUDP_CONNECTION_OUTBOUND, .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, .timeout = timeout, .confirmed = 1 }; connection->sendbuffer_length = resize_queue(&connection->sendbuffer, 0, DEFAULT_QUEUE_NUM, 0, 0); connection->recvbuffer_length = resize_queue(&connection->recvbuffer, 0, DEFAULT_QUEUE_NUM, 0, 0); if (connection->sendbuffer_length == (uint32_t)~0 || connection->recvbuffer_length == (uint32_t)~0) { free(connection->sendbuffer); free(connection->recvbuffer); memset(connection, 0, sizeof(Connection)); return -1; } return connection_id; } /* * Initialize a new inbound connection from ip_port. * * return 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; /* TODO: return existing connection instead? */ int connection_id = -1; tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_NO_CONNECTION) { connection_id = tmp_i; break; } } if (connection_id == -1) { if (tox_array_push_ptr(&ludp->connections, 0) == 0) return -1; connection_id = ludp->connections.len - 1; } Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); memset(connection, 0, sizeof(Connection)); /* Add randomness to timeout to prevent connections getting stuck in a loop. */ uint8_t timeout = CONNECTION_TIMEOUT + rand() % CONNECTION_TIMEOUT; *connection = (Connection) { .ip_port = ip_port, .status = LUDP_NOT_CONFIRMED, .inbound = LUDP_CONNECTION_INBOUND, .SYNC_rate = SYNC_RATE, .data_rate = DATA_SYNC_RATE, .last_recvSYNC = current_time(), .last_sent = current_time(), .send_counter = 127, .timeout = timeout, /* If this connection isn't handled within the timeout kill it. */ .killat = current_time() + 1000000UL * timeout, .confirmed = 0 }; connection->sendbuffer_length = resize_queue(&connection->sendbuffer, 0, DEFAULT_QUEUE_NUM, 0, 0); connection->recvbuffer_length = resize_queue(&connection->recvbuffer, 0, DEFAULT_QUEUE_NUM, 0, 0); if (connection->sendbuffer_length == (uint32_t)~0 || connection->recvbuffer_length == (uint32_t)~0) { free(connection->sendbuffer); free(connection->recvbuffer); memset(connection, 0, sizeof(Connection)); return -1; } return connection_id; } /* * return an integer corresponding to the next connection in our incoming connection list with at least numpackets in the recieve queue. * return -1 if there are no new incoming connections in the list. */ int incoming_connection(Lossless_UDP *ludp, uint32_t numpackets) { tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->inbound == LUDP_CONNECTION_INBOUND && tmp->recv_packetnum - tmp->successful_read >= numpackets) { tmp->inbound = LUDP_CONNECTION_INBOUND_HANDLED; return tmp_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.len; i != 0; --i) { Connection *connection = &tox_array_get(&ludp->connections, i - 1, Connection); if (connection->status != LUDP_NO_CONNECTION) break; } if (ludp->connections.len == i) return; return tox_array_pop(&ludp->connections, ludp->connections.len - 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 ((unsigned int)connection_id < ludp->connections.len) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status != LUDP_NO_CONNECTION) { connection->status = LUDP_NO_CONNECTION; change_handshake(ludp, connection->ip_port); free(connection->sendbuffer); free(connection->recvbuffer); memset(connection, 0, sizeof(Connection)); free_connections(ludp); return 0; } } return -1; } /* * timeout connection in seconds. * * return -1 if it can not kill the connection. * return 0 if it will kill it. */ int timeout_connection_in(Lossless_UDP *ludp, int connection_id, uint32_t seconds) { if ((unsigned int)connection_id < ludp->connections.len) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status != LUDP_NO_CONNECTION) { connection->killat = current_time() + 1000000UL * seconds; return 0; } } return -1; } /* * Check if connection is connected: * * return LUDP_NO_CONNECTION if not. * return LUDP_HANDSHAKE_SENDING if attempting handshake. * return LUDP_NOT_CONFIRMED if handshake is done. * return LUDP_ESTABLISHED if fully connected. * return LUDP_TIMED_OUT if timed out and waiting to be killed. */ int is_connected(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id < ludp->connections.len) return tox_array_get(&ludp->connections, connection_id, Connection).status; return 0; } /* Check if connection is confirmed. * * returns 1 if yes. * returns 0 if no/failure. */ int connection_confirmed(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; if (connection->confirmed == 1) return 1; return 0; } /* Confirm an incoming connection. * Also disable the auto kill timeout on incomming connections. * * return 0 on success * return -1 on failure. */ int confirm_connection(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id >= ludp->connections.len) return -1; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return -1; connection->killat = ~0; connection->confirmed = 1; connection->inbound = LUDP_CONNECTION_OUTBOUND; return 0; } /* return the ip_port of the corresponding connection. */ IP_Port connection_ip(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id < ludp->connections.len) return tox_array_get(&ludp->connections, connection_id, Connection).ip_port; IP_Port zero; ip_reset(&zero.ip); zero.port = 0; return zero; } /* return the number of packets in the queue waiting to be successfully sent. */ uint32_t sendqueue(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; return connection->sendbuff_packetnum - connection->successful_sent; } /* return number of packets in all queues waiting to be successfully sent. */ uint32_t sendqueue_total(Lossless_UDP *ludp) { uint32_t i, total = 0; for(i = 0; i < ludp->connections.len; i++) { Connection *connection = &tox_array_get(&ludp->connections, i, Connection); if (connection->status != 0) total += connection->sendbuff_packetnum - connection->successful_sent; } return total; } /* return 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 ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; return connection->recv_packetnum - connection->successful_read; } /* return 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 (recvqueue(ludp, connection_id) == 0) return -1; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status != LUDP_NO_CONNECTION) return connection->recvbuffer[connection->successful_read % connection->recvbuffer_length].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) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; uint16_t index = connection->successful_read % connection->recvbuffer_length; uint16_t size = connection->recvbuffer[index].size; memcpy(data, connection->recvbuffer[index].data, size); ++connection->successful_read; connection->recvbuffer[index].size = 0; return size; } /* Like read_packet() but does leaves the queue as is. * return 0 if there is no received data in the buffer. * return length of received packet if successful. */ int read_packet_silent(Lossless_UDP *ludp, int connection_id, uint8_t *data) { if (recvqueue(ludp, connection_id) == 0) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; uint16_t index = connection->successful_read % connection->recvbuffer_length; uint16_t size = connection->recvbuffer[index].size; memcpy(data, connection->recvbuffer[index].data, size); return size; } /* Discard the next packet to be read from the queue * return 0 if success. * return -1 if failure. */ int discard_packet(Lossless_UDP *ludp, int connection_id) { if (recvqueue(ludp, connection_id) == 0) return -1; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint16_t index = connection->successful_read % connection->recvbuffer_length; ++connection->successful_read; connection->recvbuffer[index].size = 0; return 0; } #define MAX_SYNC_RATE 20 #define MIN_SLOTS 16 /* returns the number of packet slots left in the sendbuffer. * return 0 if failure. */ uint32_t num_free_sendqueue_slots(Lossless_UDP *ludp, int connection_id) { if ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint32_t max_slots = (connection->data_rate / MAX_SYNC_RATE) * 1.5; if (max_slots > MAX_QUEUE_NUM) max_slots = MAX_QUEUE_NUM; if (max_slots < MIN_SLOTS) max_slots = MIN_SLOTS; if (sendqueue(ludp, connection_id) > max_slots) return 0; return max_slots - sendqueue(ludp, connection_id); } /* 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 ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NO_CONNECTION) return 0; if (length > MAX_DATA_SIZE || length == 0 || sendqueue(ludp, connection_id) >= MAX_QUEUE_NUM) return 0; if (num_free_sendqueue_slots(ludp, connection_id) == 0) return 0; if (sendqueue(ludp, connection_id) >= connection->sendbuffer_length && connection->sendbuffer_length != 0) { uint32_t newlen = connection->sendbuffer_length = resize_queue(&connection->sendbuffer, connection->sendbuffer_length, connection->sendbuffer_length * 2, connection->successful_sent, connection->sendbuff_packetnum); if (newlen == (uint32_t)~0) return 0; connection->sendbuffer_length = newlen; return write_packet(ludp, connection_id, data, length); } uint32_t index = connection->sendbuff_packetnum % connection->sendbuffer_length; memcpy(connection->sendbuffer[index].data, data, length); connection->sendbuffer[index].size = length; connection->sendbuff_packetnum++; return 1; } /* Put the packet numbers the we are missing in requested and return the number. */ static uint32_t missing_packets(Lossless_UDP *ludp, int connection_id, uint32_t *requested) { if ((unsigned int)connection_id >= ludp->connections.len) return 0; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); /* Don't request packets if the buffer is full. */ if (recvqueue(ludp, connection_id) >= (connection->recvbuffer_length - 1)) return 0; uint32_t number = 0; uint32_t i; uint32_t temp; for (i = connection->recv_packetnum; i != connection->osent_packetnum; i++) { if (connection->recvbuffer[i % connection->recvbuffer_length].size == 0) { temp = htonl(i); memcpy(requested + number, &temp, 4); ++number; } if (number >= MAX_REQUESTED_PACKETS) return number; } if (number == 0) connection->recv_packetnum = connection->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, ip_port, packet, sizeof(packet)); } static int send_SYNC(Lossless_UDP *ludp, int connection_id) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint8_t packet[(MAX_REQUESTED_PACKETS * 4 + 4 + 4 + 2)]; uint16_t index = 0; IP_Port ip_port = connection->ip_port; uint8_t counter = connection->send_counter; uint32_t recv_packetnum = htonl(connection->recv_packetnum); uint32_t sent_packetnum = htonl(connection->sent_packetnum); uint32_t requested[MAX_REQUESTED_PACKETS]; 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, ip_port, packet, (number * 4 + 4 + 4 + 2)); } static int send_data_packet(Lossless_UDP *ludp, int connection_id, uint32_t packet_num) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint32_t index = packet_num % connection->sendbuffer_length; 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, connection->sendbuffer[index].data, connection->sendbuffer[index].size); return sendpacket(ludp->net, connection->ip_port, packet, 1 + 4 + connection->sendbuffer[index].size); } /* Sends 1 data packet. */ static int send_DATA(Lossless_UDP *ludp, int connection_id) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); int ret; uint32_t buffer[MAX_REQUESTED_PACKETS]; if (connection->num_req_paquets > 0) { ret = send_data_packet(ludp, connection_id, connection->req_packets[0]); connection->num_req_paquets--; memcpy(buffer, connection->req_packets + 1, connection->num_req_paquets * 4); memcpy(connection->req_packets, buffer, connection->num_req_paquets * 4); return ret; } if (connection->sendbuff_packetnum != connection->sent_packetnum) { ret = send_data_packet(ludp, connection_id, connection->sent_packetnum); connection->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. * return 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_id = 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_id) != LUDP_ESTABLISHED && is_connected(ludp, connection_id) != LUDP_TIMED_OUT) { send_handshake(ludp, source, handshake_id(ludp, source), handshake_id1); return 0; } if (is_connected(ludp, connection_id) != LUDP_HANDSHAKE_SENDING) return 1; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); /* if handshake_id2 is what we sent previously as handshake_id1 */ if (handshake_id2 == connection->handshake_id1) { connection->status = LUDP_NOT_CONFIRMED; /* NOTE: Is this necessary? connection->handshake_id2 = handshake_id1; */ connection->orecv_packetnum = handshake_id2; connection->osent_packetnum = handshake_id1; connection->recv_packetnum = handshake_id1; connection->successful_read = handshake_id1; } return 0; } /* return 1 if sync packet is valid. * return 0 if not. */ static int SYNC_valid(uint32_t length) { if (length < 4 + 4 + 2) return 0; if (length > (MAX_REQUESTED_PACKETS * 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 connection_id = new_inconnection(ludp, source); if (connection_id != -1) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); connection->orecv_packetnum = recv_packetnum; connection->sent_packetnum = recv_packetnum; connection->sendbuff_packetnum = recv_packetnum; connection->successful_sent = recv_packetnum; connection->osent_packetnum = sent_packetnum; connection->recv_packetnum = sent_packetnum; connection->successful_read = sent_packetnum; return connection_id; } } 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) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (recv_packetnum == connection->orecv_packetnum && sent_packetnum == connection->osent_packetnum) { connection->status = LUDP_ESTABLISHED; connection->recv_counter = counter; ++connection->send_counter; send_SYNC(ludp, connection_id); return 0; } return 1; } /* * Automatically adjusts send rates of data packets for optimal transmission. * * TODO: Improve this. */ static void adjust_datasendspeed(Connection *connection, uint32_t req_packets) { /* if there are no packets in send buffer */ if (connection->sendbuff_packetnum - connection->successful_sent == 0) { connection->data_rate -= connection->data_rate / 8; if (connection->data_rate < DATA_SYNC_RATE) connection->data_rate = DATA_SYNC_RATE; return; } if (req_packets <= (connection->data_rate / connection->SYNC_rate) / 5 || req_packets <= 10) { connection->data_rate += (connection->data_rate / 8) + 1; if (connection->data_rate > connection->sendbuffer_length * connection->SYNC_rate) connection->data_rate = connection->sendbuffer_length * connection->SYNC_rate; } else { connection->data_rate -= connection->data_rate / 8; } } /* 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) { Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint8_t comp_counter = (counter - connection->recv_counter); uint32_t i, temp; /* uint32_t comp_1 = (recv_packetnum - connection->successful_sent); uint32_t comp_2 = (sent_packetnum - connection->successful_read); */ uint32_t comp_1 = (recv_packetnum - connection->orecv_packetnum); uint32_t comp_2 = (sent_packetnum - connection->osent_packetnum); /* Packet valid. */ if (comp_1 <= connection->sendbuffer_length && comp_2 <= MAX_QUEUE_NUM && comp_counter != 0 && comp_counter < 8) { connection->orecv_packetnum = recv_packetnum; connection->osent_packetnum = sent_packetnum; connection->successful_sent = recv_packetnum; connection->last_recvSYNC = current_time(); connection->recv_counter = counter; ++connection->send_counter; for (i = 0; i < number; ++i) { temp = ntohl(req_packets[i]); memcpy(connection->req_packets + i, &temp, sizeof(uint32_t)); } connection->num_req_paquets = number; adjust_datasendspeed(connection, 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; uint8_t counter; uint32_t temp; uint32_t recv_packetnum, sent_packetnum; uint16_t number = (length - 4 - 4 - 2) / 4; uint32_t req_packets[number]; 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); int connection_id = getconnection_id(ludp, source); if (connection_id == -1) return handle_SYNC1(ludp, source, recv_packetnum, sent_packetnum); Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); if (connection->status == LUDP_NOT_CONFIRMED) return handle_SYNC2(ludp, connection_id, counter, recv_packetnum, sent_packetnum); if (connection->status == LUDP_ESTABLISHED) return handle_SYNC3(ludp, connection_id, 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. * return 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; Connection *connection = &tox_array_get(&ludp->connections, connection_id, Connection); uint32_t i; uint32_t test = data_num - connection->recv_packetnum; if (test > MAX_QUEUE_NUM) return 0; if (test > connection->recvbuffer_length) { if (connection->confirmed == 0) return 0; uint32_t len = resize_queue(&connection->recvbuffer, connection->recvbuffer_length, test * 2, connection->successful_read, connection->successful_read + connection->recvbuffer_length); if (len == (uint32_t)~0) return 0; connection->recvbuffer_length = len; } uint32_t maxnum = connection->successful_read + connection->recvbuffer_length; uint32_t sent_packet = data_num - connection->osent_packetnum; for (i = connection->recv_packetnum; i != maxnum; ++i) { if (i == data_num) { memcpy(connection->recvbuffer[data_num % connection->recvbuffer_length].data, data, size); connection->recvbuffer[data_num % connection->recvbuffer_length].size = size; connection->last_recvdata = current_time(); if (sent_packet < connection->recvbuffer_length) connection->osent_packetnum = data_num; break; } } for (i = connection->recv_packetnum; i != maxnum; ++i) { if (connection->recvbuffer[i % connection->recvbuffer_length].size != 0) connection->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_id = getconnection_id(ludp, source); /* Drop the data packet if connection is not connected. */ if (connection_id == -1) return 1; if (tox_array_get(&ludp->connections, connection_id, Connection).status != LUDP_ESTABLISHED) 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_id, 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; tox_array_init(&temp->connections, sizeof(Connection)); 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) { uint64_t temp_time = current_time(); tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_HANDSHAKE_SENDING && (tmp->last_sent + (1000000UL / tmp->SYNC_rate)) <= temp_time) { send_handshake(ludp, tmp->ip_port, tmp->handshake_id1, 0); tmp->last_sent = temp_time; } /* kill all timed out connections */ if (tmp->status != LUDP_NO_CONNECTION && (tmp->last_recvSYNC + tmp->timeout * 1000000UL) < temp_time && tmp->status != LUDP_TIMED_OUT) { tmp->status = LUDP_TIMED_OUT; /* kill_connection(i); */ } if (tmp->status != LUDP_NO_CONNECTION && tmp->killat < temp_time) tmp->status = LUDP_TIMED_OUT; } } static void do_SYNC(Lossless_UDP *ludp) { uint64_t temp_time = current_time(); tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_NOT_CONFIRMED || tmp->status == LUDP_ESTABLISHED) if ((tmp->last_SYNC + (1000000UL / tmp->SYNC_rate)) <= temp_time) { send_SYNC(ludp, tmp_i); tmp->last_SYNC = temp_time; } } } static void do_data(Lossless_UDP *ludp) { uint64_t j; uint64_t temp_time = current_time(); tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_ESTABLISHED && sendqueue(ludp, tmp_i) != 0 && (tmp->last_sent + (1000000UL / tmp->data_rate)) <= temp_time) { for (j = tmp->last_sent; j < temp_time; j += (1000000UL / tmp->data_rate)) if (send_DATA(ludp, tmp_i) <= 0) break; tmp->last_sent = temp_time; } } } /* * Automatically adjusts send rates of packets for optimal transmission. * * TODO: Flow control. */ static void adjust_rates(Lossless_UDP *ludp) { uint64_t temp_time = current_time(); tox_array_for_each(&ludp->connections, Connection, tmp) { if (tmp->status == LUDP_HANDSHAKE_SENDING || tmp->status == LUDP_NOT_CONFIRMED) tmp->SYNC_rate = MAX_SYNC_RATE; if (tmp->status == LUDP_ESTABLISHED) { if (sendqueue(ludp, tmp_i) != 0) { tmp->SYNC_rate = MAX_SYNC_RATE; } else if (tmp->last_recvdata + 200000UL > temp_time) { /* 200 ms */ tmp->SYNC_rate = MAX_SYNC_RATE; } else { tmp->SYNC_rate = SYNC_RATE; } } } } /* Call this function a couple times per second. It is 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) { uint32_t i; for (i = 0; i < ludp->connections.len; ++i) kill_connection(ludp, i); tox_array_delete(&ludp->connections); free(ludp); }