/* DHT.c * * An implementation of the DHT as seen in docs/DHT.txt * * 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 . * */ /*----------------------------------------------------------------------------------*/ #include "DHT.h" /* maximum number of clients stored per friend. */ #define MAX_FRIEND_CLIENTS 8 /* A list of the clients mathematically closest to ours. */ #define LCLIENT_LIST 32 /* The list of ip ports along with the ping_id of what we sent them and a timestamp */ #define LPING_ARRAY 256 #define LSEND_NODES_ARRAY LPING_ARRAY/2 /* the number of seconds for a non responsive node to become bad. */ #define BAD_NODE_TIMEOUT 70 /* the max number of nodes to send with send nodes. */ #define MAX_SENT_NODES 8 /* ping timeout in seconds */ #define PING_TIMEOUT 5 /* The timeout after which a node is discarded completely. */ #define Kill_NODE_TIMEOUT 300 /* ping interval in seconds for each node in our lists. */ #define PING_INTERVAL 60 /* ping interval in seconds for each random sending of a get nodes request. */ #define GET_NODE_INTERVAL 10 #define MAX_PUNCHING_PORTS 32 /*Interval in seconds between punching attempts*/ #define PUNCH_INTERVAL 10 /*----------------------------------------------------------------------------------*/ typedef struct { uint8_t client_id[CLIENT_ID_SIZE]; IP_Port ip_port; uint32_t timestamp; uint32_t last_pinged; /* Returned by this node. Either our friend or us */ IP_Port ret_ip_port; uint32_t ret_timestamp; } Client_data; typedef struct { uint8_t client_id[CLIENT_ID_SIZE]; Client_data client_list[MAX_FRIEND_CLIENTS]; /* time at which the last get_nodes request was sent. */ uint32_t lastgetnode; /* Symetric NAT hole punching stuff */ /* 1 if currently hole punching, otherwise 0 */ uint8_t hole_punching; uint32_t punching_index; uint32_t punching_timestamp; uint32_t recvNATping_timestamp; uint64_t NATping_id; uint32_t NATping_timestamp; } Friend; typedef struct { uint8_t client_id[CLIENT_ID_SIZE]; IP_Port ip_port; } Node_format; typedef struct { IP_Port ip_port; uint64_t ping_id; uint32_t timestamp; } Pinged; /*----------------------------------------------------------------------------------*/ /* Our client id/public key */ uint8_t self_public_key[CLIENT_ID_SIZE]; uint8_t self_secret_key[crypto_box_SECRETKEYBYTES]; static Client_data close_clientlist[LCLIENT_LIST]; static Friend * friends_list; static uint16_t num_friends; static Pinged pings[LPING_ARRAY]; static Pinged send_nodes[LSEND_NODES_ARRAY]; /*----------------------------------------------------------------------------------*/ /* Compares client_id1 and client_id2 with client_id return 0 if both are same distance return 1 if client_id1 is closer return 2 if client_id2 is closer */ int id_closest(uint8_t * client_id, uint8_t * client_id1, uint8_t * client_id2) /* tested */ { uint32_t i; for(i = 0; i < CLIENT_ID_SIZE; ++i) { if(abs(client_id[i] ^ client_id1[i]) < abs(client_id[i] ^ client_id2[i])) return 1; else if(abs(client_id[i] ^ client_id1[i]) > abs(client_id[i] ^ client_id2[i])) return 2; } return 0; } /* check if client with client_id is already in list of length length. if it is set it's corresponding timestamp to current time. if the id is already in the list with a different ip_port, update it. return True(1) or False(0) TODO: maybe optimize this. */ int client_in_list(Client_data * list, uint32_t length, uint8_t * client_id, IP_Port ip_port) { uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < length; ++i) { /*If ip_port is assigned to a different client_id replace it*/ if(list[i].ip_port.ip.i == ip_port.ip.i && list[i].ip_port.port == ip_port.port) { memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE); } if(memcmp(list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) { /* Refresh the client timestamp. */ list[i].timestamp = temp_time; list[i].ip_port.ip.i = ip_port.ip.i; list[i].ip_port.port = ip_port.port; return 1; } } return 0; } /* check if client with client_id is already in node format list of length length. return True(1) or False(0) */ int client_in_nodelist(Node_format * list, uint32_t length, uint8_t * client_id) { uint32_t i; for(i = 0; i < length; ++i) if(memcmp(list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) return 1; return 0; } /*Return the friend number from the client_id Return -1 if failure, number of friend if success*/ static int friend_number(uint8_t * client_id) { uint32_t i; for(i = 0; i < num_friends; ++i) if(memcmp(friends_list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) /* Equal */ return i; return -1; } /* Find MAX_SENT_NODES nodes closest to the client_id for the send nodes request: put them in the nodes_list and return how many were found. TODO: Make this function much more efficient. */ int get_close_nodes(uint8_t * client_id, Node_format * nodes_list) { uint32_t i, j, k; int num_nodes=0; uint32_t temp_time = unix_time(); for(i = 0; i < LCLIENT_LIST; ++i) if(close_clientlist[i].timestamp + BAD_NODE_TIMEOUT > temp_time && !client_in_nodelist(nodes_list, MAX_SENT_NODES,close_clientlist[i].client_id)) { /* if node is good and not already in list. */ if(num_nodes < MAX_SENT_NODES) { memcpy(nodes_list[num_nodes].client_id, close_clientlist[i].client_id, CLIENT_ID_SIZE); nodes_list[num_nodes].ip_port = close_clientlist[i].ip_port; num_nodes++; } else for(j = 0; j < MAX_SENT_NODES; ++j) if(id_closest(client_id, nodes_list[j].client_id, close_clientlist[i].client_id) == 2) { memcpy(nodes_list[j].client_id, close_clientlist[i].client_id, CLIENT_ID_SIZE); nodes_list[j].ip_port = close_clientlist[i].ip_port; break; } } for(i = 0; i < num_friends; ++i) for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) if(friends_list[i].client_list[j].timestamp + BAD_NODE_TIMEOUT > temp_time && !client_in_nodelist(nodes_list, MAX_SENT_NODES,friends_list[i].client_list[j].client_id)) { /* if node is good and not already in list. */ if(num_nodes < MAX_SENT_NODES) { memcpy(nodes_list[num_nodes].client_id, friends_list[i].client_list[j].client_id, CLIENT_ID_SIZE); nodes_list[num_nodes].ip_port = friends_list[i].client_list[j].ip_port; num_nodes++; } else for(k = 0; k < MAX_SENT_NODES; ++k) if(id_closest(client_id, nodes_list[k].client_id, friends_list[i].client_list[j].client_id) == 2) { memcpy(nodes_list[k].client_id, friends_list[i].client_list[j].client_id, CLIENT_ID_SIZE); nodes_list[k].ip_port = friends_list[i].client_list[j].ip_port; break; } } return num_nodes; } /* replace first bad (or empty) node with this one return 0 if successful return 1 if not (list contains no bad nodes) */ int replace_bad(Client_data * list, uint32_t length, uint8_t * client_id, IP_Port ip_port) /* tested */ { uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < length; ++i) if(list[i].timestamp + BAD_NODE_TIMEOUT < temp_time) { /* if node is bad. */ memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE); list[i].ip_port = ip_port; list[i].timestamp = temp_time; list[i].ret_ip_port.ip.i = 0; list[i].ret_ip_port.port = 0; list[i].ret_timestamp = 0; return 0; } return 1; } /* replace the first good node that is further to the comp_client_id than that of the client_id in the list */ int replace_good(Client_data * list, uint32_t length, uint8_t * client_id, IP_Port ip_port, uint8_t * comp_client_id) { uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < length; ++i) if(id_closest(comp_client_id, list[i].client_id, client_id) == 2) { memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE); list[i].ip_port = ip_port; list[i].timestamp = temp_time; list[i].ret_ip_port.ip.i = 0; list[i].ret_ip_port.port = 0; list[i].ret_timestamp = 0; return 0; } return 1; } /* Attempt to add client with ip_port and client_id to the friends client list and close_clientlist */ void addto_lists(IP_Port ip_port, uint8_t * client_id) { uint32_t i; /* NOTE: current behavior if there are two clients with the same id is to replace the first ip by the second. */ if(!client_in_list(close_clientlist, LCLIENT_LIST, client_id, ip_port)) if(replace_bad(close_clientlist, LCLIENT_LIST, client_id, ip_port)) /* if we can't replace bad nodes we try replacing good ones */ replace_good(close_clientlist, LCLIENT_LIST, client_id, ip_port, self_public_key); for(i = 0; i < num_friends; ++i) if(!client_in_list(friends_list[i].client_list, MAX_FRIEND_CLIENTS, client_id, ip_port)) if(replace_bad(friends_list[i].client_list, MAX_FRIEND_CLIENTS, client_id, ip_port)) /* if we can't replace bad nodes we try replacing good ones. */ replace_good(friends_list[i].client_list, MAX_FRIEND_CLIENTS, client_id, ip_port, friends_list[i].client_id); } /* If client_id is a friend or us, update ret_ip_port nodeclient_id is the id of the node that sent us this info */ void returnedip_ports(IP_Port ip_port, uint8_t * client_id, uint8_t * nodeclient_id) { uint32_t i, j; uint32_t temp_time = unix_time(); if(memcmp(client_id, self_public_key, CLIENT_ID_SIZE) == 0) { for(i = 0; i < LCLIENT_LIST; ++i) if(memcmp(nodeclient_id, close_clientlist[i].client_id, CLIENT_ID_SIZE) == 0) { close_clientlist[i].ret_ip_port = ip_port; close_clientlist[i].ret_timestamp = temp_time; return; } } else for(i = 0; i < num_friends; ++i) if(memcmp(client_id, friends_list[i].client_id, CLIENT_ID_SIZE) == 0) for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) if(memcmp(nodeclient_id, friends_list[i].client_list[j].client_id, CLIENT_ID_SIZE) == 0) { friends_list[i].client_list[j].ret_ip_port = ip_port; friends_list[i].client_list[j].ret_timestamp = temp_time; return; } } /* check if we are currently pinging an ip_port and/or a ping_id variables with values of zero will not be checked. if we are already, return 1 else return 0 TODO: optimize this */ int is_pinging(IP_Port ip_port, uint64_t ping_id) { uint32_t i; uint8_t pinging; uint32_t temp_time = unix_time(); for(i = 0; i < LPING_ARRAY; ++i ) if((pings[i].timestamp + PING_TIMEOUT) > temp_time) { pinging = 0; if(ip_port.ip.i != 0) if(pings[i].ip_port.ip.i == ip_port.ip.i && pings[i].ip_port.port == ip_port.port) ++pinging; if(ping_id != 0) if(pings[i].ping_id == ping_id) ++pinging; if(pinging == (ping_id != 0) + (ip_port.ip.i != 0)) return 1; } return 0; } /* Same as last function but for get_node requests. */ int is_gettingnodes(IP_Port ip_port, uint64_t ping_id) { uint32_t i; uint8_t pinging; uint32_t temp_time = unix_time(); for(i = 0; i < LSEND_NODES_ARRAY; ++i ) if((send_nodes[i].timestamp + PING_TIMEOUT) > temp_time) { pinging = 0; if(ip_port.ip.i != 0) if(send_nodes[i].ip_port.ip.i == ip_port.ip.i && send_nodes[i].ip_port.port == ip_port.port) ++pinging; if(ping_id != 0) if(send_nodes[i].ping_id == ping_id) ++pinging; if(pinging == (ping_id != 0) + (ip_port.ip.i != 0)) return 1; } return 0; } /* Add a new ping request to the list of ping requests returns the ping_id to put in the ping request returns 0 if problem. TODO: optimize this */ uint64_t add_pinging(IP_Port ip_port) { uint32_t i, j; uint64_t ping_id = ((uint64_t)random_int() << 32) + random_int(); uint32_t temp_time = unix_time(); for(i = 0; i < PING_TIMEOUT; ++i ) for(j = 0; j < LPING_ARRAY; ++j ) if((pings[j].timestamp + PING_TIMEOUT - i) < temp_time) { pings[j].timestamp = temp_time; pings[j].ip_port = ip_port; pings[j].ping_id = ping_id; return ping_id; } return 0; } /* Same but for get node requests */ uint64_t add_gettingnodes(IP_Port ip_port) { uint32_t i, j; uint64_t ping_id = ((uint64_t)random_int() << 32) + random_int(); uint32_t temp_time = unix_time(); for(i = 0; i < PING_TIMEOUT; ++i ) for(j = 0; j < LSEND_NODES_ARRAY; ++j ) if((send_nodes[j].timestamp + PING_TIMEOUT - i) < temp_time) { send_nodes[j].timestamp = temp_time; send_nodes[j].ip_port = ip_port; send_nodes[j].ping_id = ping_id; return ping_id; } return 0; } /* send a ping request Ping request only works if none has been sent to that ip/port in the last 5 seconds. */ static int pingreq(IP_Port ip_port, uint8_t * public_key) { if(memcmp(public_key, self_public_key, CLIENT_ID_SIZE) == 0) /* check if packet is gonna be sent to ourself */ return 1; if(is_pinging(ip_port, 0)) return 1; uint64_t ping_id = add_pinging(ip_port); if(ping_id == 0) return 1; uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING]; uint8_t encrypt[sizeof(ping_id) + ENCRYPTION_PADDING]; uint8_t nonce[crypto_box_NONCEBYTES]; random_nonce(nonce); int len = encrypt_data(public_key, self_secret_key, nonce, (uint8_t *)&ping_id, sizeof(ping_id), encrypt); if(len != sizeof(ping_id) + ENCRYPTION_PADDING) return -1; data[0] = 0; memcpy(data + 1, self_public_key, CLIENT_ID_SIZE); memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES); memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len); return sendpacket(ip_port, data, sizeof(data)); } /* send a ping response */ static int pingres(IP_Port ip_port, uint8_t * public_key, uint64_t ping_id) { /* check if packet is gonna be sent to ourself */ if(memcmp(public_key, self_public_key, CLIENT_ID_SIZE) == 0) return 1; uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING]; uint8_t encrypt[sizeof(ping_id) + ENCRYPTION_PADDING]; uint8_t nonce[crypto_box_NONCEBYTES]; random_nonce(nonce); int len = encrypt_data(public_key, self_secret_key, nonce, (uint8_t *)&ping_id, sizeof(ping_id), encrypt); if(len != sizeof(ping_id) + ENCRYPTION_PADDING) return -1; data[0] = 1; memcpy(data + 1, self_public_key, CLIENT_ID_SIZE); memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES); memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len); return sendpacket(ip_port, data, sizeof(data)); } /* send a getnodes request */ static int getnodes(IP_Port ip_port, uint8_t * public_key, uint8_t * client_id) { /* check if packet is gonna be sent to ourself */ if(memcmp(public_key, self_public_key, CLIENT_ID_SIZE) == 0) return 1; if(is_gettingnodes(ip_port, 0)) return 1; uint64_t ping_id = add_gettingnodes(ip_port); if(ping_id == 0) return 1; uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING]; uint8_t plain[sizeof(ping_id) + CLIENT_ID_SIZE]; uint8_t encrypt[sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING]; uint8_t nonce[crypto_box_NONCEBYTES]; random_nonce(nonce); memcpy(plain, &ping_id, sizeof(ping_id)); memcpy(plain + sizeof(ping_id), client_id, CLIENT_ID_SIZE); int len = encrypt_data(public_key, self_secret_key, nonce, plain, sizeof(ping_id) + CLIENT_ID_SIZE, encrypt); if(len != sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING) return -1; data[0] = 2; memcpy(data + 1, self_public_key, CLIENT_ID_SIZE); memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES); memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len); return sendpacket(ip_port, data, sizeof(data)); } /* send a send nodes response */ static int sendnodes(IP_Port ip_port, uint8_t * public_key, uint8_t * client_id, uint64_t ping_id) { if(memcmp(public_key, self_public_key, CLIENT_ID_SIZE) == 0) /* check if packet is gonna be sent to ourself */ return 1; uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES + ENCRYPTION_PADDING]; Node_format nodes_list[MAX_SENT_NODES]; int num_nodes = get_close_nodes(client_id, nodes_list); if(num_nodes == 0) return 0; uint8_t plain[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES]; uint8_t encrypt[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES + ENCRYPTION_PADDING]; uint8_t nonce[crypto_box_NONCEBYTES]; random_nonce(nonce); memcpy(plain, &ping_id, sizeof(ping_id)); memcpy(plain + sizeof(ping_id), nodes_list, num_nodes * sizeof(Node_format)); int len = encrypt_data(public_key, self_secret_key, nonce, plain, sizeof(ping_id) + num_nodes * sizeof(Node_format), encrypt); if(len != sizeof(ping_id) + num_nodes * sizeof(Node_format) + ENCRYPTION_PADDING) return -1; data[0] = 3; memcpy(data + 1, self_public_key, CLIENT_ID_SIZE); memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES); memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len); return sendpacket(ip_port, data, 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + len); } /* Packet handling functions One to handle each types of packets we receive return 0 if handled correctly, 1 if packet is bad. */ int handle_pingreq(uint8_t * packet, uint32_t length, IP_Port source) { uint64_t ping_id; if(length != 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING) return 1; /* check if packet is from ourself. */ if(memcmp(packet + 1, self_public_key, CLIENT_ID_SIZE) == 0) return 1; int len = decrypt_data(packet + 1, self_secret_key, packet + 1 + CLIENT_ID_SIZE, packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, sizeof(ping_id) + ENCRYPTION_PADDING, (uint8_t *)&ping_id); if(len != sizeof(ping_id)) return 1; pingres(source, packet + 1, ping_id); pingreq(source, packet + 1); /* TODO: make this smarter? */ return 0; } int handle_pingres(uint8_t * packet, uint32_t length, IP_Port source) { uint64_t ping_id; if(length != 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING) return 1; if(memcmp(packet + 1, self_public_key, CLIENT_ID_SIZE) == 0) /* check if packet is from ourself. */ return 1; int len = decrypt_data(packet + 1, self_secret_key, packet + 1 + CLIENT_ID_SIZE, packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, sizeof(ping_id) + ENCRYPTION_PADDING, (uint8_t *)&ping_id); if(len != sizeof(ping_id)) return 1; if(is_pinging(source, ping_id)) { addto_lists(source, packet + 1); return 0; } return 1; } int handle_getnodes(uint8_t * packet, uint32_t length, IP_Port source) { uint64_t ping_id; if(length != 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING) return 1; /* check if packet is from ourself. */ if(memcmp(packet + 1, self_public_key, CLIENT_ID_SIZE) == 0) return 1; uint8_t plain[sizeof(ping_id) + CLIENT_ID_SIZE]; int len = decrypt_data(packet + 1, self_secret_key, packet + 1 + CLIENT_ID_SIZE, packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING, plain); if(len != sizeof(ping_id) + CLIENT_ID_SIZE) return 1; memcpy(&ping_id, plain, sizeof(ping_id)); sendnodes(source, packet + 1, plain + sizeof(ping_id), ping_id); pingreq(source, packet + 1); /* TODO: make this smarter? */ return 0; } int handle_sendnodes(uint8_t * packet, uint32_t length, IP_Port source) { uint64_t ping_id; /* TODO: make this more readable */ if(length > (1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES + ENCRYPTION_PADDING) || (length - (1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING)) % (sizeof(Node_format)) != 0 || length < 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + sizeof(Node_format) + ENCRYPTION_PADDING) { return 1; } uint32_t num_nodes = (length - (1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING)) / sizeof(Node_format); uint8_t plain[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES]; int len = decrypt_data(packet + 1, self_secret_key, packet + 1 + CLIENT_ID_SIZE, packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, sizeof(ping_id) + num_nodes * sizeof(Node_format) + ENCRYPTION_PADDING, plain); if(len != sizeof(ping_id) + num_nodes * sizeof(Node_format)) return 1; memcpy(&ping_id, plain, sizeof(ping_id)); if(!is_gettingnodes(source, ping_id)) return 1; Node_format nodes_list[MAX_SENT_NODES]; memcpy(nodes_list, plain + sizeof(ping_id), num_nodes * sizeof(Node_format)); addto_lists(source, packet + 1); uint32_t i; for(i = 0; i < num_nodes; ++i) { pingreq(nodes_list[i].ip_port, nodes_list[i].client_id); returnedip_ports(nodes_list[i].ip_port, nodes_list[i].client_id, packet + 1); } return 0; } /*----------------------------------------------------------------------------------*/ /*------------------------END of packet handling functions--------------------------*/ int DHT_addfriend(uint8_t * client_id) { Friend * temp; temp = realloc(friends_list, sizeof(Friend) * (num_friends + 1)); if(temp == NULL) return 1; friends_list = temp; memset(&friends_list[num_friends], 0, sizeof(Friend)); memcpy(friends_list[num_friends].client_id, client_id, CLIENT_ID_SIZE); friends_list[num_friends].NATping_id = ((uint64_t)random_int() << 32) + random_int(); ++num_friends; return 0; } int DHT_delfriend(uint8_t * client_id) { uint32_t i; Friend * temp; for(i = 0; i < num_friends; ++i) /* Equal */ if(memcmp(friends_list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) { --num_friends; if(num_friends != i) memcpy(friends_list[i].client_id, friends_list[num_friends].client_id, CLIENT_ID_SIZE); temp = realloc(friends_list, sizeof(Friend) * (num_friends)); if(temp != NULL) friends_list = temp; return 0; } return 1; } /* TODO: Optimize this. */ IP_Port DHT_getfriendip(uint8_t * client_id) { uint32_t i, j; IP_Port empty = {{{0}}, 0}; uint32_t temp_time = unix_time(); for(i = 0; i < num_friends; ++i) /* Equal */ if(memcmp(friends_list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) { for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) if(memcmp(friends_list[i].client_list[j].client_id, client_id, CLIENT_ID_SIZE) == 0 && friends_list[i].client_list[j].timestamp + BAD_NODE_TIMEOUT > temp_time) return friends_list[i].client_list[j].ip_port; return empty; } empty.ip.i = 1; return empty; } /* Ping each client in the "friends" list every 60 seconds. Send a get nodes request every 20 seconds to a random good node for each "friend" in our "friends" list. */ void doDHTFriends() { uint32_t i, j; uint32_t temp_time = unix_time(); uint32_t rand_node; uint32_t index[MAX_FRIEND_CLIENTS]; for(i = 0; i < num_friends; ++i) { uint32_t num_nodes = 0; for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) if(friends_list[i].client_list[j].timestamp + Kill_NODE_TIMEOUT > temp_time) { /* if node is not dead. */ if((friends_list[i].client_list[j].last_pinged + PING_INTERVAL) <= temp_time) { pingreq(friends_list[i].client_list[j].ip_port, friends_list[i].client_list[j].client_id); friends_list[i].client_list[j].last_pinged = temp_time; } if(friends_list[i].client_list[j].timestamp + BAD_NODE_TIMEOUT > temp_time) { /* if node is good. */ index[num_nodes] = j; ++num_nodes; } } if(friends_list[i].lastgetnode + GET_NODE_INTERVAL <= temp_time && num_nodes != 0) { rand_node = rand() % num_nodes; getnodes(friends_list[i].client_list[index[rand_node]].ip_port, friends_list[i].client_list[index[rand_node]].client_id, friends_list[i].client_id); friends_list[i].lastgetnode = temp_time; } } } static uint32_t close_lastgetnodes; /* Ping each client in the close nodes list every 60 seconds. Send a get nodes request every 20 seconds to a random good node in the list. */ void doClose() /* tested */ { uint32_t i; uint32_t temp_time = unix_time(); uint32_t num_nodes = 0; uint32_t rand_node; uint32_t index[LCLIENT_LIST]; for(i = 0; i < LCLIENT_LIST; ++i) /* if node is not dead. */ if(close_clientlist[i].timestamp + Kill_NODE_TIMEOUT > temp_time) { if((close_clientlist[i].last_pinged + PING_INTERVAL) <= temp_time) { pingreq(close_clientlist[i].ip_port, close_clientlist[i].client_id); close_clientlist[i].last_pinged = temp_time; } /* if node is good. */ if(close_clientlist[i].timestamp + BAD_NODE_TIMEOUT > temp_time) { index[num_nodes] = i; ++num_nodes; } } if(close_lastgetnodes + GET_NODE_INTERVAL <= temp_time && num_nodes != 0) { rand_node = rand() % num_nodes; getnodes(close_clientlist[index[rand_node]].ip_port, close_clientlist[index[rand_node]].client_id, self_public_key); close_lastgetnodes = temp_time; } } void DHT_bootstrap(IP_Port ip_port, uint8_t * public_key) { getnodes(ip_port, public_key, self_public_key); } /* send the given packet to node with client_id returns -1 if failure */ int route_packet(uint8_t * client_id, uint8_t * packet, uint32_t length) { uint32_t i; for(i = 0; i < LCLIENT_LIST; ++i) if(memcmp(client_id, close_clientlist[i].client_id, CLIENT_ID_SIZE) == 0) return sendpacket(close_clientlist[i].ip_port, packet, length); return -1; } /* Puts all the different ips returned by the nodes for a friend_num into array ip_portlist ip_portlist must be at least MAX_FRIEND_CLIENTS big returns the number of ips returned return 0 if we are connected to friend or if no ips were found. returns -1 if no such friend*/ static int friend_iplist(IP_Port * ip_portlist, uint16_t friend_num) { int num_ips = 0; uint32_t i; uint32_t temp_time = unix_time(); if(friend_num >= num_friends) return -1; for(i = 0; i < MAX_FRIEND_CLIENTS; ++i) /*If ip is not zero and node is good */ if(friends_list[friend_num].client_list[i].ret_ip_port.ip.i != 0 && friends_list[friend_num].client_list[i].ret_timestamp + BAD_NODE_TIMEOUT > temp_time) { if(memcmp(friends_list[friend_num].client_list[i].client_id, friends_list[friend_num].client_id, CLIENT_ID_SIZE) == 0 ) return 0; ip_portlist[num_ips] = friends_list[friend_num].client_list[i].ret_ip_port; ++num_ips; } return num_ips; } /* Send the following packet to everyone who tells us they are connected to friend_id returns the number of nodes it sent the packet to */ int route_tofriend(uint8_t * friend_id, uint8_t * packet, uint32_t length) { uint32_t i, j; uint32_t sent = 0; uint32_t temp_time = unix_time(); for(i = 0; i < num_friends; ++i) /* Equal */ if(memcmp(friends_list[i].client_id, friend_id, CLIENT_ID_SIZE) == 0) { for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) /*If ip is not zero and node is good */ if(friends_list[i].client_list[j].ret_ip_port.ip.i != 0 && friends_list[i].client_list[j].ret_timestamp + BAD_NODE_TIMEOUT > temp_time) if(sendpacket(friends_list[i].client_list[j].ip_port, packet, length) == length) ++sent; return sent; } return 0; } /* Send the following packet to one random person who tells us they are connected to friend_id returns the number of nodes it sent the packet to */ int routeone_tofriend(uint8_t * friend_id, uint8_t * packet, uint32_t length) { int num = friend_number(friend_id); if(num == -1) return 0; IP_Port ip_list[MAX_FRIEND_CLIENTS]; int n = 0; uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < MAX_FRIEND_CLIENTS; ++i) /*If ip is not zero and node is good */ if(friends_list[num].client_list[i].ret_ip_port.ip.i != 0 && friends_list[num].client_list[i].ret_timestamp + BAD_NODE_TIMEOUT > temp_time) { ip_list[n] = friends_list[num].client_list[i].ip_port; ++n; } if(n < 1) return 0; if(sendpacket(ip_list[rand() % n], packet, length) == length) return 1; return 0; } /* Puts all the different ips returned by the nodes for a friend_id into array ip_portlist ip_portlist must be at least MAX_FRIEND_CLIENTS big returns the number of ips returned return 0 if we are connected to friend or if no ips were found. returns -1 if no such friend*/ int friend_ips(IP_Port * ip_portlist, uint8_t * friend_id) { uint32_t i; for(i = 0; i < num_friends; ++i) /* Equal */ if(memcmp(friends_list[i].client_id, friend_id, CLIENT_ID_SIZE) == 0) return friend_iplist(ip_portlist, i); return -1; } /*----------------------------------------------------------------------------------*/ /*---------------------BEGINNING OF NAT PUNCHING FUNCTIONS--------------------------*/ int send_NATping(uint8_t * public_key, uint64_t ping_id, uint8_t type) { uint8_t data[sizeof(uint64_t) + 1]; data[0] = type; memcpy(data + 1, &ping_id, sizeof(uint64_t)); uint8_t packet[MAX_DATA_SIZE]; int len = create_request(packet, public_key, data, sizeof(uint64_t) + 1, 254); /* 254 is NAT ping request packet id */ if(len == -1) return -1; int num = 0; if(type == 0) num = route_tofriend(public_key, packet, len);/*If packet is request use many people to route it*/ else if(type == 1) num = routeone_tofriend(public_key, packet, len);/*If packet is response use only one person to route it*/ if(num == 0) return -1; return num; } /* Handle a recieved ping request for */ int handle_NATping(uint8_t * packet, uint32_t length, IP_Port source) { if(length <= crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING && length > MAX_DATA_SIZE + ENCRYPTION_PADDING) return 1; /* check if request is for us. */ if(memcmp(packet + 1, self_public_key, crypto_box_PUBLICKEYBYTES) == 0) { uint8_t public_key[crypto_box_PUBLICKEYBYTES]; uint8_t data[MAX_DATA_SIZE]; int len = handle_request(public_key, data, packet, length); if(len != sizeof(uint64_t) + 1) return 1; uint64_t ping_id; memcpy(&ping_id, data + 1, sizeof(uint64_t)); int friendnumber = friend_number(public_key); if(friendnumber == -1) return 1; if(data[0] == 0) { send_NATping(public_key, ping_id, 1); /*1 is reply*/ friends_list[friendnumber].recvNATping_timestamp = unix_time(); return 0; } else if (data[0] == 1) if(friends_list[friendnumber].NATping_id == ping_id) { friends_list[friendnumber].NATping_id = ((uint64_t)random_int() << 32) + random_int(); friends_list[friendnumber].hole_punching = 1; return 0; } return 1; } /* if request is not for us, try routing it. */ else if(route_packet(packet + 1, packet, length) == length) return 0; return 0; } /*Get the most common ip in the ip_portlist Only return ip if it appears in list min_num or more len must not be bigger than MAX_FRIEND_CLIENTS return ip of 0 if failure */ static IP NAT_commonip(IP_Port * ip_portlist, uint16_t len, uint16_t min_num) { IP zero = {{0}}; if(len > MAX_FRIEND_CLIENTS) return zero; uint32_t i, j; uint16_t numbers[MAX_FRIEND_CLIENTS] = {0}; for(i = 0; i < len; ++i) { for(j = 0; j < len; ++j) if(ip_portlist[i].ip.i == ip_portlist[j].ip.i) ++numbers[i]; if(numbers[i] >= min_num) return ip_portlist[i].ip; } return zero; } /*Return all the ports for one ip in a list portlist must be at least len long where len is the length of ip_portlist returns the number of ports and puts the list of ports in portlist*/ static uint16_t NAT_getports(uint16_t * portlist, IP_Port * ip_portlist, uint16_t len, IP ip) { uint32_t i; uint16_t num = 0; for(i = 0; i < len; ++i) if(ip_portlist[i].ip.i == ip.i) { portlist[num] = ntohs(ip_portlist[i].port); ++num; } return num; } static void punch_holes(IP ip, uint16_t * port_list, uint16_t numports, uint16_t friend_num) { if(numports > MAX_FRIEND_CLIENTS || numports == 0) return; uint32_t i; uint32_t top = friends_list[friend_num].punching_index + MAX_PUNCHING_PORTS; for(i = friends_list[friend_num].punching_index; i != top; i++) { /*TODO: improve port guessing algorithm*/ uint16_t port = port_list[(i/2) % numports] + (i/(2*numports))*((i % 2) ? -1 : 1); IP_Port pinging = {ip, htons(port)}; pingreq(pinging, friends_list[friend_num].client_id); } friends_list[friend_num].punching_index = i; } static void doNAT() { uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < num_friends; ++i) { IP_Port ip_list[MAX_FRIEND_CLIENTS]; int num = friend_iplist(ip_list, i); /*If we are connected to friend or if friend is not online don't try to hole punch with him*/ if(num < MAX_FRIEND_CLIENTS/2) continue; if(friends_list[i].NATping_timestamp + PUNCH_INTERVAL < temp_time) { send_NATping(friends_list[i].client_id, friends_list[i].NATping_id, 0); /*0 is request*/ friends_list[i].NATping_timestamp = temp_time; } if(friends_list[i].hole_punching == 1 && friends_list[i].punching_timestamp + PUNCH_INTERVAL < temp_time && friends_list[i].recvNATping_timestamp + PUNCH_INTERVAL*2 >= temp_time) { IP ip = NAT_commonip(ip_list, num, MAX_FRIEND_CLIENTS/2); if(ip.i == 0) continue; uint16_t port_list[MAX_FRIEND_CLIENTS]; uint16_t numports = NAT_getports(port_list, ip_list, num, ip); punch_holes(ip, port_list, numports, i); friends_list[i].punching_timestamp = temp_time; friends_list[i].hole_punching = 0; } } } /*----------------------------------------------------------------------------------*/ /*-----------------------END OF NAT PUNCHING FUNCTIONS------------------------------*/ int DHT_handlepacket(uint8_t * packet, uint32_t length, IP_Port source) { switch (packet[0]) { case 0: return handle_pingreq(packet, length, source); case 1: return handle_pingres(packet, length, source); case 2: return handle_getnodes(packet, length, source); case 3: return handle_sendnodes(packet, length, source); case 254: return handle_NATping(packet, length, source); default: return 1; } return 0; } void doDHT() { doClose(); doDHTFriends(); doNAT(); } /* get the size of the DHT (for saving) */ uint32_t DHT_size() { return sizeof(close_clientlist) + sizeof(Friend) * num_friends; } /* save the DHT in data where data is an array of size DHT_size() */ void DHT_save(uint8_t * data) { memcpy(data, close_clientlist, sizeof(close_clientlist)); memcpy(data + sizeof(close_clientlist), friends_list, sizeof(Friend) * num_friends); } /* load the DHT from data of size size; return -1 if failure return 0 if success */ int DHT_load(uint8_t * data, uint32_t size) { if(size < sizeof(close_clientlist)) return -1; if((size - sizeof(close_clientlist)) % sizeof(Friend) != 0) return -1; uint32_t i, j; /* uint32_t temp_time = unix_time(); */ uint16_t temp; temp = (size - sizeof(close_clientlist))/sizeof(Friend); if(temp != 0) { Friend * tempfriends_list = (Friend *)(data + sizeof(close_clientlist)); for(i = 0; i < temp; ++i) { DHT_addfriend(tempfriends_list[i].client_id); for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) if(tempfriends_list[i].client_list[j].timestamp != 0) { getnodes(tempfriends_list[i].client_list[j].ip_port, tempfriends_list[i].client_list[j].client_id, tempfriends_list[i].client_id); } } } Client_data * tempclose_clientlist = (Client_data *)data; for(i = 0; i < LCLIENT_LIST; ++i) if(tempclose_clientlist[i].timestamp != 0) DHT_bootstrap(tempclose_clientlist[i].ip_port, tempclose_clientlist[i].client_id); return 0; } /* returns 0 if we are not connected to the DHT returns 1 if we are */ int DHT_isconnected() { uint32_t i; uint32_t temp_time = unix_time(); for(i = 0; i < LCLIENT_LIST; ++i) if(close_clientlist[i].timestamp + BAD_NODE_TIMEOUT > temp_time) return 1; return 0; }