/* return length of received packet on success.
* return 0 if could not read any packet.
* return -1 on failure (connection must be killed).
*/
int read_packet_TCP_secure_connection(sock_t sock, uint16_t *next_packet_length, const uint8_t *shared_key,
uint8_t *recv_nonce, uint8_t *data, uint16_t max_len)
{
if (*next_packet_length == 0) {
uint16_t len = read_TCP_length(sock);
if (len == (uint16_t)~0)
return -1;
if (len == 0)
return 0;
*next_packet_length = len;
}
if (max_len + crypto_box_MACBYTES < *next_packet_length)
return -1;
uint8_t data_encrypted[*next_packet_length];
int len_packet = read_TCP_packet(sock, data_encrypted, *next_packet_length);
if (len_packet != *next_packet_length)
return 0;
*next_packet_length = 0;
int len = decrypt_data_symmetric(shared_key, recv_nonce, data_encrypted, len_packet, data);
if (len + crypto_box_MACBYTES != len_packet)
return -1;
increment_nonce(recv_nonce);
return len;
}
/* return length of recieved packet on success.
* return 0 if could not read any packet.
* return -1 on failure (connection must be killed).
*/
static int read_packet_TCP_secure_connection(TCP_Secure_Connection *con, uint8_t *data, uint16_t max_len)
{
if (con->next_packet_length == 0) {
uint16_t len = read_length(con->sock);
if (len == (uint16_t)~0)
return -1;
if (len == 0)
return 0;
con->next_packet_length = len;
}
if (max_len + crypto_box_MACBYTES < con->next_packet_length)
return -1;
uint8_t data_encrypted[con->next_packet_length];
int len_packet = read_TCP_packet(con->sock, data_encrypted, con->next_packet_length);
if (len_packet != con->next_packet_length)
return 0;
con->next_packet_length = 0;
int len = decrypt_data_fast(con->shared_key, con->recv_nonce, data_encrypted, len_packet, data);
if (len + crypto_box_MACBYTES != len_packet)
return -1;
increment_nonce(con->recv_nonce);
return len;
}
/* return 1 if connection handshake was handled correctly.
* return 0 if we didn't get it yet.
* return -1 if the connection must be killed.
*/
static int read_connection_handshake(TCP_Secure_Connection *con, const uint8_t *self_secret_key)
{
uint8_t data[TCP_CLIENT_HANDSHAKE_SIZE];
int len = 0;
if ((len = read_TCP_packet(con->sock, data, TCP_CLIENT_HANDSHAKE_SIZE)) != -1) {
return handle_TCP_handshake(con, data, len, self_secret_key);
}
return 0;
}
/* return 1 on success.
* return 0 if no data received.
* return -1 on failure (connection refused).
*/
static int socks5_read_handshake_response(TCP_Client_Connection *TCP_conn)
{
uint8_t data[2];
int ret = read_TCP_packet(TCP_conn->sock, data, sizeof(data));
if (ret == -1) {
return 0;
}
if (data[0] == 5 && data[1] == 0) { // TODO(irungentoo): magic numbers
return 1;
}
return -1;
}
/* return length of received packet on success.
* return 0 if could not read any packet.
* return -1 on failure (connection must be killed).
*/
int read_packet_TCP_secure_connection(Socket sock, uint16_t *next_packet_length, const uint8_t *shared_key,
uint8_t *recv_nonce, uint8_t *data, uint16_t max_len)
{
if (*next_packet_length == 0) {
uint16_t len = read_TCP_length(sock);
if (len == (uint16_t)~0) {
return -1;
}
if (len == 0) {
return 0;
}
*next_packet_length = len;
}
if (max_len + CRYPTO_MAC_SIZE < *next_packet_length) {
return -1;
}
VLA(uint8_t, data_encrypted, *next_packet_length);
int len_packet = read_TCP_packet(sock, data_encrypted, *next_packet_length);
if (len_packet != *next_packet_length) {
return 0;
}
*next_packet_length = 0;
int len = decrypt_data_symmetric(shared_key, recv_nonce, data_encrypted, len_packet, data);
if (len + CRYPTO_MAC_SIZE != len_packet) {
return -1;
}
increment_nonce(recv_nonce);
return len;
}
/* Run the TCP connection
*/
void do_TCP_connection(TCP_Client_Connection *TCP_connection, void *userdata)
{
unix_time_update();
if (TCP_connection->status == TCP_CLIENT_DISCONNECTED) {
return;
}
if (TCP_connection->status == TCP_CLIENT_PROXY_HTTP_CONNECTING) {
if (send_pending_data(TCP_connection) == 0) {
int ret = proxy_http_read_connection_response(TCP_connection);
if (ret == -1) {
TCP_connection->kill_at = 0;
TCP_connection->status = TCP_CLIENT_DISCONNECTED;
}
if (ret == 1) {
generate_handshake(TCP_connection);
TCP_connection->status = TCP_CLIENT_CONNECTING;
}
}
}
if (TCP_connection->status == TCP_CLIENT_PROXY_SOCKS5_CONNECTING) {
if (send_pending_data(TCP_connection) == 0) {
int ret = socks5_read_handshake_response(TCP_connection);
if (ret == -1) {
TCP_connection->kill_at = 0;
TCP_connection->status = TCP_CLIENT_DISCONNECTED;
}
if (ret == 1) {
proxy_socks5_generate_connection_request(TCP_connection);
TCP_connection->status = TCP_CLIENT_PROXY_SOCKS5_UNCONFIRMED;
}
}
}
if (TCP_connection->status == TCP_CLIENT_PROXY_SOCKS5_UNCONFIRMED) {
if (send_pending_data(TCP_connection) == 0) {
int ret = proxy_socks5_read_connection_response(TCP_connection);
if (ret == -1) {
TCP_connection->kill_at = 0;
TCP_connection->status = TCP_CLIENT_DISCONNECTED;
}
if (ret == 1) {
generate_handshake(TCP_connection);
TCP_connection->status = TCP_CLIENT_CONNECTING;
}
}
}
if (TCP_connection->status == TCP_CLIENT_CONNECTING) {
if (send_pending_data(TCP_connection) == 0) {
TCP_connection->status = TCP_CLIENT_UNCONFIRMED;
}
}
if (TCP_connection->status == TCP_CLIENT_UNCONFIRMED) {
uint8_t data[TCP_SERVER_HANDSHAKE_SIZE];
int len = read_TCP_packet(TCP_connection->sock, data, sizeof(data));
if (sizeof(data) == len) {
if (handle_handshake(TCP_connection, data) == 0) {
TCP_connection->kill_at = ~0;
TCP_connection->status = TCP_CLIENT_CONFIRMED;
} else {
TCP_connection->kill_at = 0;
TCP_connection->status = TCP_CLIENT_DISCONNECTED;
}
}
}
if (TCP_connection->status == TCP_CLIENT_CONFIRMED) {
do_confirmed_TCP(TCP_connection, userdata);
}
if (TCP_connection->kill_at <= unix_time()) {
TCP_connection->status = TCP_CLIENT_DISCONNECTED;
}
}