/** Creates a STUN request and sends it to a random STUN server selected from
* the list stored in the config file. See
* https://tools.ietf.org/html/rfc5389#section-6
* for details on the message structure.
* The request is send through m_transaction_host, from which the answer
* will be retrieved by parseStunResponse()
*/
void GetPublicAddress::createStunRequest()
{
// Pick a random stun server
std::vector<std::string> stun_servers = UserConfigParams::m_stun_servers;
const char* server_name = stun_servers[rand() % stun_servers.size()].c_str();
Log::debug("GetPublicAddress", "Using STUN server %s", server_name);
struct addrinfo hints, *res;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // AF_INET or AF_INET6 to force version
hints.ai_socktype = SOCK_STREAM;
// Resolve the stun server name so we can send it a STUN request
int status = getaddrinfo(server_name, NULL, &hints, &res);
if (status != 0)
{
Log::error("GetPublicAddress", "Error in getaddrinfo: %s",
gai_strerror(status));
return;
}
// documentation says it points to "one or more addrinfo structures"
assert(res != NULL);
struct sockaddr_in* current_interface = (struct sockaddr_in*)(res->ai_addr);
m_stun_server_ip = ntohl(current_interface->sin_addr.s_addr);
// Create a new socket for the stun server.
m_transaction_host = new Network(1, 1, 0, 0);
// Assemble the message for the stun server
BareNetworkString s(21);
// bytes 0-1: the type of the message
// bytes 2-3: message length added to header (attributes)
uint16_t message_type = 0x0001; // binding request
uint16_t message_length = 0x0000;
s.addUInt16(message_type).addUInt16(message_length)
.addUInt32(0x2112A442);
// bytes 8-19: the transaction id
for (int i = 0; i < 12; i++)
{
uint8_t random_byte = rand() % 256;
s.addUInt8(random_byte);
m_stun_tansaction_id[i] = random_byte;
}
s.addChar(0);
m_transaction_host->sendRawPacket(s,
TransportAddress(m_stun_server_ip,
m_stun_server_port) );
freeaddrinfo(res);
m_state = STUN_REQUEST_SENT;
} // createStunRequest
void GetPublicAddress::asynchronousUpdate()
{
if (m_state == NOTHING_DONE)
{
// format : 00MMMMMCMMMCMMMM (cf rfc 5389)
uint16_t message_type = 0x0001; // binding request
m_stun_tansaction_id[0] = stunRand();
m_stun_tansaction_id[1] = stunRand();
m_stun_tansaction_id[2] = stunRand();
uint16_t message_length = 0x0000;
uint8_t bytes[21]; // the message to be sent
// bytes 0-1 : the type of the message,
bytes[0] = (uint8_t)(message_type>>8);
bytes[1] = (uint8_t)(message_type);
// bytes 2-3 : message length added to header (attributes)
bytes[2] = (uint8_t)(message_length>>8);
bytes[3] = (uint8_t)(message_length);
// bytes 4-7 : magic cookie to recognize the stun protocol
bytes[4] = (uint8_t)(m_stun_magic_cookie>>24);
bytes[5] = (uint8_t)(m_stun_magic_cookie>>16);
bytes[6] = (uint8_t)(m_stun_magic_cookie>>8);
bytes[7] = (uint8_t)(m_stun_magic_cookie);
// bytes 8-19 : the transaction id
bytes[8] = (uint8_t)(m_stun_tansaction_id[0]>>24);
bytes[9] = (uint8_t)(m_stun_tansaction_id[0]>>16);
bytes[10] = (uint8_t)(m_stun_tansaction_id[0]>>8);
bytes[11] = (uint8_t)(m_stun_tansaction_id[0]);
bytes[12] = (uint8_t)(m_stun_tansaction_id[1]>>24);
bytes[13] = (uint8_t)(m_stun_tansaction_id[1]>>16);
bytes[14] = (uint8_t)(m_stun_tansaction_id[1]>>8);
bytes[15] = (uint8_t)(m_stun_tansaction_id[1]);
bytes[16] = (uint8_t)(m_stun_tansaction_id[2]>>24);
bytes[17] = (uint8_t)(m_stun_tansaction_id[2]>>16);
bytes[18] = (uint8_t)(m_stun_tansaction_id[2]>>8);
bytes[19] = (uint8_t)(m_stun_tansaction_id[2]);
bytes[20] = '\0';
// time to pick a random stun server
std::vector<std::string> stun_servers = UserConfigParams::m_stun_servers;
RandomGenerator random_gen;
int rand_result = random_gen.get((int)stun_servers.size());
Log::verbose("GetPublicAddress", "Using STUN server %s",
stun_servers[rand_result].c_str());
// resolve the name into an IP address
struct addrinfo hints, *res, *p;
int status;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // AF_INET or AF_INET6 to force version
hints.ai_socktype = SOCK_STREAM;
if ((status = getaddrinfo(stun_servers[rand_result].c_str(), NULL, &hints, &res)) != 0) {
Log::error("getaddrinfo", gai_strerror(status));
return;
}
for(p = res;p != NULL; p = p->ai_next)
{
struct sockaddr_in* current_interface = (struct sockaddr_in*)(p->ai_addr);
m_stun_server_ip = ntohl(current_interface->sin_addr.s_addr);
m_transaction_host = new STKHost();
m_transaction_host->setupClient(1,1,0,0);
m_transaction_host->sendRawPacket(bytes, 20, TransportAddress(m_stun_server_ip, 3478));
m_state = TEST_SENT;
freeaddrinfo(res); // free the linked list
return;
}
freeaddrinfo(res); // free the linked list
}