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toxcore/core/net_crypto.c
irungentoo 45fec94452 Fixed segfault and removed deprecated code.
2013-08-18 11:01:15 -04:00

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/* net_crypto.c
*
* Functions for the core network crypto.
* See also: http://wiki.tox.im/index.php/DHT
*
* NOTE: This code has to be perfect. We don't mess around with encryption.
*
* 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 "net_crypto.h"
/* Our public and secret keys. */
uint8_t self_public_key[crypto_box_PUBLICKEYBYTES];
uint8_t self_secret_key[crypto_box_SECRETKEYBYTES];
typedef struct {
uint8_t public_key[crypto_box_PUBLICKEYBYTES]; /* the real public key of the peer. */
uint8_t recv_nonce[crypto_box_NONCEBYTES]; /* nonce of received packets */
uint8_t sent_nonce[crypto_box_NONCEBYTES]; /* nonce of sent packets. */
uint8_t sessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* our public key for this session. */
uint8_t sessionsecret_key[crypto_box_SECRETKEYBYTES]; /* our private key for this session. */
uint8_t peersessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* The public key of the peer. */
uint8_t shared_key[crypto_box_BEFORENMBYTES]; /* the precomputed shared key from encrypt_precompute */
uint8_t status; /* 0 if no connection, 1 we have sent a handshake, 2 if connexion is not confirmed yet
(we have received a handshake but no empty data packet), 3 if the connection is established.
4 if the connection is timed out. */
uint16_t number; /* Lossless_UDP connection number corresponding to this connection. */
} Crypto_Connection;
static Crypto_Connection *crypto_connections;
static uint32_t crypto_connections_length; /* Length of connections array */
#define MAX_CRYPTO_CONNECTIONS crypto_connections_length
#define CONN_NO_CONNECTION 0
#define CONN_HANDSHAKE_SENT 1
#define CONN_NOT_CONFIRMED 2
#define CONN_ESTABLISHED 3
#define CONN_TIMED_OUT 4
#define MAX_INCOMING 64
/* keeps track of the connection numbers for friends request so we can check later if they were sent */
static int incoming_connections[MAX_INCOMING];
/* Use this instead of memcmp; not vulnerable to timing attacks. */
uint8_t crypto_iszero(uint8_t *mem, uint32_t length)
{
uint8_t check = 0;
uint32_t i;
for (i = 0; i < length; ++i) {
check |= mem[i];
}
return check; // We return zero if mem is made out of zeroes.
}
/* Precomputes the shared key from their public_key and our secret_key.
This way we can avoid an expensive elliptic curve scalar multiply for each
encrypt/decrypt operation.
enc_key has to be crypto_box_BEFORENMBYTES bytes long. */
void encrypt_precompute(uint8_t *public_key, uint8_t *secret_key, uint8_t *enc_key)
{
crypto_box_beforenm(enc_key, public_key, secret_key);
}
/* Fast encrypt. Depends on enc_key from encrypt_precompute. */
int encrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted)
{
if (length + crypto_box_MACBYTES > MAX_DATA_SIZE || length == 0)
return -1;
uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_ZEROBYTES] = {0};
uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
memcpy(temp_plain + crypto_box_ZEROBYTES, plain, length); /* pad the message with 32 0 bytes. */
crypto_box_afternm(temp_encrypted, temp_plain, length + crypto_box_ZEROBYTES, nonce, enc_key);
if (crypto_iszero(temp_encrypted, crypto_box_BOXZEROBYTES) != 0)
return -1;
/* unpad the encrypted message */
memcpy(encrypted, temp_encrypted + crypto_box_BOXZEROBYTES, length + crypto_box_MACBYTES);
return length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES;
}
/* Fast decrypt. Depends on enc_ley from encrypt_precompute. */
int decrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain)
{
if (length > MAX_DATA_SIZE || length <= crypto_box_BOXZEROBYTES)
return -1;
uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_ZEROBYTES];
uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
memcpy(temp_encrypted + crypto_box_BOXZEROBYTES, encrypted, length); /* pad the message with 16 0 bytes. */
if (crypto_box_open_afternm(temp_plain, temp_encrypted, length + crypto_box_BOXZEROBYTES,
nonce, enc_key) == -1)
return -1;
/* if decryption is successful the first crypto_box_ZEROBYTES of the message will be zero
apparently memcmp should not be used so we do this instead:*/
if (crypto_iszero(temp_plain, crypto_box_ZEROBYTES) != 0)
return -1;
/* unpad the plain message */
memcpy(plain, temp_plain + crypto_box_ZEROBYTES, length - crypto_box_MACBYTES);
return length - crypto_box_ZEROBYTES + crypto_box_BOXZEROBYTES;
}
int encrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted)
{
uint8_t k[crypto_box_BEFORENMBYTES];
encrypt_precompute(public_key, secret_key, k);
return encrypt_data_fast(k, nonce, plain, length, encrypted);
}
int decrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain)
{
uint8_t k[crypto_box_BEFORENMBYTES];
encrypt_precompute(public_key, secret_key, k);
return decrypt_data_fast(k, nonce, encrypted, length, plain);
}
/* increment the given nonce by 1 */
static void increment_nonce(uint8_t *nonce)
{
uint32_t i;
for (i = 0; i < crypto_box_NONCEBYTES; ++i) {
++nonce[i];
if (nonce[i] != 0)
break;
}
}
/* fill the given nonce with random bytes. */
void random_nonce(uint8_t *nonce)
{
uint32_t i, temp;
for (i = 0; i < crypto_box_NONCEBYTES / 4; ++i) {
temp = random_int();
memcpy(nonce + 4 * i, &temp, 4);
}
}
/* return 0 if there is no received data in the buffer
return -1 if the packet was discarded.
return length of received data if successful */
int read_cryptpacket(int crypt_connection_id, uint8_t *data)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 0;
if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int length = read_packet(crypto_connections[crypt_connection_id].number, temp_data);
if (length == 0)
return 0;
if (temp_data[0] != 3)
return -1;
int len = decrypt_data_fast(crypto_connections[crypt_connection_id].shared_key,
crypto_connections[crypt_connection_id].recv_nonce,
temp_data + 1, length - 1, data);
if (len != -1) {
increment_nonce(crypto_connections[crypt_connection_id].recv_nonce);
return len;
}
return -1;
}
/* return 0 if data could not be put in packet queue
return 1 if data was put into the queue */
int write_cryptpacket(int crypt_connection_id, uint8_t *data, uint32_t length)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 0;
if (length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES > MAX_DATA_SIZE - 1)
return 0;
if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int len = encrypt_data_fast(crypto_connections[crypt_connection_id].shared_key,
crypto_connections[crypt_connection_id].sent_nonce,
data, length, temp_data + 1);
if (len == -1)
return 0;
temp_data[0] = 3;
if (write_packet(crypto_connections[crypt_connection_id].number, temp_data, len + 1) == 0)
return 0;
increment_nonce(crypto_connections[crypt_connection_id].sent_nonce);
return 1;
}
/* create a request to peer with public_key.
packet must be an array of MAX_DATA_SIZE big.
Data represents the data we send with the request with length being the length of the data.
request_id is the id of the request (32 = friend request, 254 = ping request)
returns -1 on failure
returns the length of the created packet on success */
int create_request(uint8_t *packet, uint8_t *public_key, uint8_t *data, uint32_t length, uint8_t request_id)
{
if (MAX_DATA_SIZE < length + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING)
return -1;
uint8_t nonce[crypto_box_NONCEBYTES];
uint8_t temp[MAX_DATA_SIZE];
memcpy(temp + 1, data, length);
temp[0] = request_id;
random_nonce(nonce);
int len = encrypt_data(public_key, self_secret_key, nonce, temp, length + 1,
1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + packet);
if (len == -1)
return -1;
packet[0] = 32;
memcpy(packet + 1, public_key, crypto_box_PUBLICKEYBYTES);
memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES * 2, nonce, crypto_box_NONCEBYTES);
return len + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES;
}
/* puts the senders public key in the request in public_key, the data from the request
in data if a friend or ping request was sent to us and returns the length of the data.
packet is the request packet and length is its length
return -1 if not valid request. */
static int handle_request(uint8_t *public_key, uint8_t *data, uint8_t *request_id, uint8_t *packet, uint16_t length)
{
if (length > crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING &&
length <= MAX_DATA_SIZE + ENCRYPTION_PADDING &&
memcmp(packet + 1, self_public_key, crypto_box_PUBLICKEYBYTES) == 0) {
memcpy(public_key, packet + 1 + crypto_box_PUBLICKEYBYTES, crypto_box_PUBLICKEYBYTES);
uint8_t nonce[crypto_box_NONCEBYTES];
uint8_t temp[MAX_DATA_SIZE];
memcpy(nonce, packet + 1 + crypto_box_PUBLICKEYBYTES * 2, crypto_box_NONCEBYTES);
int len1 = decrypt_data(public_key, self_secret_key, nonce,
packet + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES,
length - (crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1), temp);
if (len1 == -1 || len1 == 0)
return -1;
request_id[0] = temp[0];
--len1;
memcpy(data, temp + 1, len1);
return len1;
} else
return -1;
}
static cryptopacket_handler_callback cryptopackethandlers[256] = {0};
void cryptopacket_registerhandler(uint8_t byte, cryptopacket_handler_callback cb)
{
cryptopackethandlers[byte] = cb;
}
static int cryptopacket_handle(IP_Port source, uint8_t *packet, uint32_t length)
{
if (packet[0] == 32) {
if (length <= crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING ||
length > MAX_DATA_SIZE + ENCRYPTION_PADDING)
return 1;
if (memcmp(packet + 1, self_public_key, crypto_box_PUBLICKEYBYTES) == 0) {// check if request is for us.
uint8_t public_key[crypto_box_PUBLICKEYBYTES];
uint8_t data[MAX_DATA_SIZE];
uint8_t number;
int len = handle_request(public_key, data, &number, packet, length);
if (len == -1 || len == 0)
return 1;
if (!cryptopackethandlers[number]) return 1;
cryptopackethandlers[number](source, public_key, data, len);
} else { /* if request is not for us, try routing it. */
if (route_packet(packet + 1, packet, length) == length)
return 0;
}
}
return 1;
}
/* Send a crypto handshake packet containing an encrypted secret nonce and session public key
to peer with connection_id and public_key
the packet is encrypted with a random nonce which is sent in plain text with the packet */
static int send_cryptohandshake(int connection_id, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
memcpy(temp, secret_nonce, crypto_box_NONCEBYTES);
memcpy(temp + crypto_box_NONCEBYTES, session_key, crypto_box_PUBLICKEYBYTES);
int len = encrypt_data(public_key, self_secret_key, nonce, temp, crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + temp_data);
if (len == -1)
return 0;
temp_data[0] = 2;
memcpy(temp_data + 1, self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(temp_data + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES);
return write_packet(connection_id, temp_data, len + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES);
}
/* Extract secret nonce, session public key and public_key from a packet(data) with length length
return 1 if successful
return 0 if failure */
static int handle_cryptohandshake(uint8_t *public_key, uint8_t *secret_nonce,
uint8_t *session_key, uint8_t *data, uint16_t length)
{
int pad = (- crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES);
if (length != 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES
+ crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad) {
return 0;
}
if (data[0] != 2)
return 0;
uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
memcpy(public_key, data + 1, crypto_box_PUBLICKEYBYTES);
int len = decrypt_data(public_key, self_secret_key, data + 1 + crypto_box_PUBLICKEYBYTES,
data + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES,
crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad, temp);
if (len != crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES)
return 0;
memcpy(secret_nonce, temp, crypto_box_NONCEBYTES);
memcpy(session_key, temp + crypto_box_NONCEBYTES, crypto_box_PUBLICKEYBYTES);
return 1;
}
/* get crypto connection id from public key of peer
return -1 if there are no connections like we are looking for
return id if it found it */
static int getcryptconnection_id(uint8_t *public_key)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status != CONN_NO_CONNECTION)
if (memcmp(public_key, crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0)
return i;
}
return -1;
}
/* set the size of the friend list to numfriends
return -1 if realloc fails */
int realloc_cryptoconnection(uint32_t num)
{
if (num == 0) {
free(crypto_connections);
crypto_connections = NULL;
return 0;
}
Crypto_Connection *newcrypto_connections = realloc(crypto_connections, num * sizeof(Crypto_Connection));
if (newcrypto_connections == NULL)
return -1;
crypto_connections = newcrypto_connections;
return 0;
}
/* Start a secure connection with other peer who has public_key and ip_port
returns -1 if failure
returns crypt_connection_id of the initialized connection if everything went well. */
int crypto_connect(uint8_t *public_key, IP_Port ip_port)
{
uint32_t i;
int id = getcryptconnection_id(public_key);
if (id != -1) {
IP_Port c_ip = connection_ip(crypto_connections[id].number);
if (c_ip.ip.i == ip_port.ip.i && c_ip.port == ip_port.port)
return -1;
}
if (realloc_cryptoconnection(crypto_connections_length + 1) == -1)
return -1;
memset(&crypto_connections[crypto_connections_length], 0, sizeof(Crypto_Connection));
crypto_connections[crypto_connections_length].number = ~0;
for (i = 0; i <= MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status == CONN_NO_CONNECTION) {
int id = new_connection(ip_port);
if (id == -1)
return -1;
crypto_connections[i].number = id;
crypto_connections[i].status = CONN_HANDSHAKE_SENT;
random_nonce(crypto_connections[i].recv_nonce);
memcpy(crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(crypto_connections[i].sessionpublic_key, crypto_connections[i].sessionsecret_key);
if (crypto_connections_length == i)
++crypto_connections_length;
if (send_cryptohandshake(id, public_key, crypto_connections[i].recv_nonce,
crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(crypto_connections[i].recv_nonce);
return i;
}
return -1; /* this should never happen. */
}
}
return -1;
}
/* handle an incoming connection
return -1 if no crypto inbound connection
return incoming connection id (Lossless_UDP one) if there is an incoming crypto connection
Put the public key of the peer in public_key, the secret_nonce from the handshake into secret_nonce
and the session public key for the connection in session_key
to accept it see: accept_crypto_inbound(...)
to refuse it just call kill_connection(...) on the connection id */
int crypto_inbound(uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
uint32_t i;
for (i = 0; i < MAX_INCOMING; ++i) {
if (incoming_connections[i] != -1) {
if (is_connected(incoming_connections[i]) == 4 || is_connected(incoming_connections[i]) == 0) {
kill_connection(incoming_connections[i]);
incoming_connections[i] = -1;
continue;
}
if (id_packet(incoming_connections[i]) == 2) {
uint8_t temp_data[MAX_DATA_SIZE];
uint16_t len = read_packet(incoming_connections[i], temp_data);
if (handle_cryptohandshake(public_key, secret_nonce, session_key, temp_data, len)) {
int connection_id = incoming_connections[i];
incoming_connections[i] = -1; /* remove this connection from the incoming connection list. */
return connection_id;
}
}
}
}
return -1;
}
/* kill a crypto connection
return 0 if killed successfully
return 1 if there was a problem. */
int crypto_kill(int crypt_connection_id)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 1;
if (crypto_connections[crypt_connection_id].status != CONN_NO_CONNECTION) {
crypto_connections[crypt_connection_id].status = CONN_NO_CONNECTION;
kill_connection(crypto_connections[crypt_connection_id].number);
memset(&crypto_connections[crypt_connection_id], 0 , sizeof(Crypto_Connection));
crypto_connections[crypt_connection_id].number = ~0;
uint32_t i;
for (i = crypto_connections_length; i != 0; --i) {
if (crypto_connections[i - 1].status != CONN_NO_CONNECTION)
break;
}
crypto_connections_length = i;
realloc_cryptoconnection(crypto_connections_length);
return 0;
}
return 1;
}
/* accept an incoming connection using the parameters provided by crypto_inbound
return -1 if not successful
returns the crypt_connection_id if successful */
int accept_crypto_inbound(int connection_id, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
uint32_t i;
if (connection_id == -1)
return -1;
/*
if(getcryptconnection_id(public_key) != -1)
{
return -1;
}*/
if (realloc_cryptoconnection(crypto_connections_length + 1) == -1)
return -1;
memset(&crypto_connections[crypto_connections_length], 0, sizeof(Crypto_Connection));
crypto_connections[crypto_connections_length].number = ~0;
for (i = 0; i <= MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status == CONN_NO_CONNECTION) {
crypto_connections[i].number = connection_id;
crypto_connections[i].status = CONN_NOT_CONFIRMED;
random_nonce(crypto_connections[i].recv_nonce);
memcpy(crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(crypto_connections[i].sent_nonce);
memcpy(crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(crypto_connections[i].sessionpublic_key, crypto_connections[i].sessionsecret_key);
if (crypto_connections_length == i)
++crypto_connections_length;
if (send_cryptohandshake(connection_id, public_key, crypto_connections[i].recv_nonce,
crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(crypto_connections[i].recv_nonce);
uint32_t zero = 0;
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED; /* connection status needs to be 3 for write_cryptpacket() to work */
write_cryptpacket(i, ((uint8_t *)&zero), sizeof(zero));
crypto_connections[i].status = CONN_NOT_CONFIRMED; /* set it to its proper value right after. */
return i;
}
return -1; /* this should never happen. */
}
}
return -1;
}
/* return 0 if no connection, 1 we have sent a handshake, 2 if connection is not confirmed yet
(we have received a handshake but no empty data packet), 3 if the connection is established.
4 if the connection is timed out and waiting to be killed */
int is_cryptoconnected(int crypt_connection_id)
{
if (crypt_connection_id >= 0 && crypt_connection_id < MAX_CRYPTO_CONNECTIONS)
return crypto_connections[crypt_connection_id].status;
return CONN_NO_CONNECTION;
}
/* Generate our public and private keys
Only call this function the first time the program starts. */
void new_keys(void)
{
crypto_box_keypair(self_public_key, self_secret_key);
}
/* save the public and private keys to the keys array
Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES */
void save_keys(uint8_t *keys)
{
memcpy(keys, self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(keys + crypto_box_PUBLICKEYBYTES, self_secret_key, crypto_box_SECRETKEYBYTES);
}
/* load the public and private keys from the keys array
Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES */
void load_keys(uint8_t *keys)
{
memcpy(self_public_key, keys, crypto_box_PUBLICKEYBYTES);
memcpy(self_secret_key, keys + crypto_box_PUBLICKEYBYTES, crypto_box_SECRETKEYBYTES);
}
/* TODO: optimize this
adds an incoming connection to the incoming_connection list.
returns 0 if successful
returns 1 if failure */
static int new_incoming(int id)
{
uint32_t i;
for (i = 0; i < MAX_INCOMING; ++i) {
if (incoming_connections[i] == -1) {
incoming_connections[i] = id;
return 0;
}
}
return 1;
}
/* TODO: optimize this
handle all new incoming connections. */
static void handle_incomings(void)
{
int income;
while (1) {
income = incoming_connection();
if (income == -1 || new_incoming(income) )
break;
}
}
/* handle received packets for not yet established crypto connections. */
static void receive_crypto(void)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status == CONN_HANDSHAKE_SENT) {
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t secret_nonce[crypto_box_NONCEBYTES];
uint8_t public_key[crypto_box_PUBLICKEYBYTES];
uint8_t session_key[crypto_box_PUBLICKEYBYTES];
uint16_t len;
if (id_packet(crypto_connections[i].number) == 2) { /* handle handshake packet. */
len = read_packet(crypto_connections[i].number, temp_data);
if (handle_cryptohandshake(public_key, secret_nonce, session_key, temp_data, len)) {
if (memcmp(public_key, crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0) {
memcpy(crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(crypto_connections[i].sent_nonce);
uint32_t zero = 0;
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED; /* connection status needs to be 3 for write_cryptpacket() to work */
write_cryptpacket(i, ((uint8_t *)&zero), sizeof(zero));
crypto_connections[i].status = CONN_NOT_CONFIRMED; /* set it to its proper value right after. */
}
}
} else if (id_packet(crypto_connections[i].number) != -1) { // This should not happen kill the connection if it does
crypto_kill(crypto_connections[i].number);
return;
}
}
if (crypto_connections[i].status == CONN_NOT_CONFIRMED) {
if (id_packet(crypto_connections[i].number) == 3) {
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t data[MAX_DATA_SIZE];
int length = read_packet(crypto_connections[i].number, temp_data);
int len = decrypt_data(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].recv_nonce, temp_data + 1, length - 1, data);
uint32_t zero = 0;
if (len == sizeof(uint32_t) && memcmp(((uint8_t *)&zero), data, sizeof(uint32_t)) == 0) {
increment_nonce(crypto_connections[i].recv_nonce);
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED;
/* connection is accepted so we disable the auto kill by setting it to about 1 month from now. */
kill_connection_in(crypto_connections[i].number, 3000000);
} else {
crypto_kill(crypto_connections[i].number); // This should not happen kill the connection if it does
return;
}
} else if (id_packet(crypto_connections[i].number) != -1)
/* This should not happen
kill the connection if it does */
crypto_kill(crypto_connections[i].number);
return;
}
}
}
/* run this to (re)initialize net_crypto
sets all the global connection variables to their default values. */
void initNetCrypto(void)
{
memset(incoming_connections, -1 , sizeof(incoming_connections));
networking_registerhandler(32, &cryptopacket_handle);
}
static void killTimedout(void)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status != CONN_NO_CONNECTION && is_connected(crypto_connections[i].number) == 4)
crypto_connections[i].status = CONN_TIMED_OUT;
else if (is_connected(crypto_connections[i].number) == 4) {
kill_connection(crypto_connections[i].number);
crypto_connections[i].number = ~0;
}
}
}
/* main loop */
void doNetCrypto(void)
{
/* TODO:check if friend requests were sent correctly
handle new incoming connections
handle friend requests */
handle_incomings();
receive_crypto();
killTimedout();
}
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