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toxcore/core/DHT.c
jvrv a72777ed70 fix comments of some files
2013-07-20 00:00:10 -03:00

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/* 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 <http://www.gnu.org/licenses/>.
*/
#include "DHT.h"
typedef struct
{
uint8_t client_id[CLIENT_ID_SIZE];
IP_Port ip_port;
uint32_t timestamp;
uint32_t last_pinged;
}Client_data;
/* maximum number of clients stored per friend. */
#define MAX_FRIEND_CLIENTS 8
typedef struct
{
uint8_t client_id[CLIENT_ID_SIZE];
Client_data client_list[MAX_FRIEND_CLIENTS];
uint32_t lastgetnode; /* time at which the last get_nodes request was sent. */
}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];
/* TODO: Move these out of here and put them into the .c file.
A list of the clients mathematically closest to ours. */
#define LCLIENT_LIST 32
static Client_data close_clientlist[LCLIENT_LIST];
static Friend * friends_list;
static uint16_t num_friends;
/* The list of ip ports along with the ping_id of what we sent them and a timestamp */
#define LPING_ARRAY 128
static Pinged pings[LPING_ARRAY];
#define LSEND_NODES_ARRAY LPING_ARRAY/2
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(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;
}
/* the number of seconds for a non responsive node to become bad. */
#define BAD_NODE_TIMEOUT 130
/* the max number of nodes to send with send nodes. */
#define MAX_SENT_NODES 8
/* 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;
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;
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);
}
}
}
}
/* ping timeout in seconds */
#define PING_TIMEOUT 5
/* 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)
{
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) + 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)
{
if(memcmp(public_key, self_public_key, CLIENT_ID_SIZE) == 0) /* check if packet is gonna be sent to ourself */
{
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;
}
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;
}
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;
}
if(memcmp(packet + 1, self_public_key, CLIENT_ID_SIZE) == 0) /* check if packet is from ourself. */
{
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;
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));
uint32_t i;
for(i = 0; i < num_nodes; ++i)
{
pingreq(nodes_list[i].ip_port, nodes_list[i].client_id);
}
addto_lists(source, packet + 1);
return 0;
}
/* END of packet handling functions */
int DHT_addfriend(uint8_t * client_id)
{
Friend * temp;
if(num_friends == 0)
{
temp = malloc(sizeof(Friend));
}
else
{
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);
++num_friends;
return 0;
}
int DHT_delfriend(uint8_t * client_id)
{
uint32_t i;
Friend * temp;
for(i = 0; i < num_friends; ++i)
{
if(memcmp(friends_list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) /* Equal */
{
--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)
{
if(memcmp(friends_list[i].client_id, client_id, CLIENT_ID_SIZE) == 0) /* Equal */
{
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;
}
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);
default:
return 1;
}
return 0;
}
/* 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
/* 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 num_nodes = 0;
uint32_t rand_node;
uint32_t index[MAX_FRIEND_CLIENTS];
for(i = 0; i < num_friends; ++i)
{
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(close_clientlist[i].timestamp + Kill_NODE_TIMEOUT > temp_time) /* if node is not dead. */
{
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(close_clientlist[i].timestamp + BAD_NODE_TIMEOUT > temp_time) /* if node is good. */
{
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 doDHT()
{
doClose();
doDHTFriends();
}
void DHT_bootstrap(IP_Port ip_port, uint8_t * public_key)
{
getnodes(ip_port, public_key, self_public_key);
}
/* 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;
}
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