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Use NetworkString for stun response data.

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This commit is contained in:
hiker 2015-10-14 00:18:13 +11:00
parent 192e2f99b5
commit beca77e94f
2 changed files with 58 additions and 54 deletions
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104
src/network/protocols/get_public_address.cpp
View File

@ -43,8 +43,15 @@
#include <sys/types.h>
// make the linker happy
const uint8_t GetPublicAddress::m_stun_magic_cookie[4] = {0x21, 0x12, 0xA4, 0x42};
const uint32_t GetPublicAddress::m_stun_magic_cookie = 0x2112A442;
GetPublicAddress::GetPublicAddress(CallbackObject* callback_object)
: Protocol(callback_object, PROTOCOL_SILENT)
{
m_state = NOTHING_DONE;
} // GetPublicAddress
// ----------------------------------------------------------------------------
/** 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.
@ -53,32 +60,7 @@ const uint8_t GetPublicAddress::m_stun_magic_cookie[4] = {0x21, 0x12, 0xA4, 0x42
*/
void GetPublicAddress::createStunRequest()
{
uint8_t bytes[21]; // the message to be sent
// bytes 0-1: the type of the message
uint16_t message_type = 0x0001; // binding request
bytes[0] = (uint8_t)(message_type>>8);
bytes[1] = (uint8_t)(message_type);
// bytes 2-3: message length added to header (attributes)
uint16_t message_length = 0x0000;
bytes[2] = (uint8_t)(message_length>>8);
bytes[3] = (uint8_t)(message_length);
// bytes 4-7: magic cookie to recognize the stun protocol
for (int i = 0; i < 4; i++)
bytes[i + 4] = m_stun_magic_cookie[i];
// bytes 8-19: the transaction id
for (int i = 0; i < 12; i++)
{
uint8_t random_byte = rand() % 256;
bytes[i+8] = random_byte;
m_stun_tansaction_id[i] = random_byte;
}
bytes[20] = '\0';
// time to pick a random stun server
// 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();
@ -98,12 +80,31 @@ void GetPublicAddress::createStunRequest()
return;
}
assert(res != NULL); // documentation says it points to "one or more addrinfo structures"
struct sockaddr_in* current_interface = (struct sockaddr_in*)(res->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, m_stun_server_port));
// Assemble the message for the stun server
NetworkString s;
// 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)
.addInt(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.getBytes(), 20, TransportAddress(m_stun_server_ip, m_stun_server_port));
freeaddrinfo(res);
m_state = STUN_REQUEST_SENT;
} // createStunRequest
@ -116,31 +117,38 @@ void GetPublicAddress::createStunRequest()
*/
std::string GetPublicAddress::parseStunResponse()
{
uint8_t* data = m_transaction_host->receiveRawPacket(TransportAddress(m_stun_server_ip, m_stun_server_port), 2000);
if (!data)
uint8_t* s = m_transaction_host->receiveRawPacket(TransportAddress(m_stun_server_ip, m_stun_server_port), 2000);
if (!s)
return "STUN response contains no data at all";
// Convert to network string.
// FIXME: the length is not known (atm 2048 bytes are allocated in
// receiveRawPacket, and it looks like 32 are actually used in a normal stun reply
NetworkString datas(std::string((char*)s, 32));
// The received data has been copied and can now be deleted
delete s;
// check that the stun response is a response, contains the magic cookie and the transaction ID
if (data[0] != 0x01 || data[1] != 0x01)
if (datas.getUInt16(0) != 0x0101)
return "STUN response doesn't contain the magic cookie";
for (int i = 0; i < 4; i++)
if (datas.getUInt32(4) != m_stun_magic_cookie)
{
if (data[i + 4] != m_stun_magic_cookie[i])
return "STUN response doesn't contain the magic cookie";
}
for (int i = 0; i < 12; i++)
{
if (data[i+8] != m_stun_tansaction_id[i])
if (datas.getUInt8(i+8) != m_stun_tansaction_id[i])
return "STUN response doesn't contain the transaction ID";
}
Log::debug("GetPublicAddress", "The STUN server responded with a valid answer");
int message_size = data[2]*256+data[3];
int message_size = datas.getUInt16(2);
// The stun message is valid, so we parse it now:
uint8_t* attributes = data+20;
if (message_size == 0)
return "STUN response does not contain any information.";
if (message_size < 4) // cannot even read the size
@ -150,30 +158,26 @@ std::string GetPublicAddress::parseStunResponse()
// Those are the port and the address to be detected
uint16_t port;
uint32_t address;
int pos = 20;
while (true)
{
int type = attributes[0]*256+attributes[1];
int size = attributes[2]*256+attributes[3];
int type = datas.getUInt16(pos);
int size = datas.getUInt16(pos+2);
if (type == 0 || type == 1)
{
assert(size == 8);
assert(attributes[5] == 0x01); // IPv4 only
port = attributes[6]*256+attributes[7];
// The (IPv4) address was sent as 4 distinct bytes,
// but needs to be packed into one 4-byte int
address = (attributes[8]<<24 & 0xFF000000) +
(attributes[9]<<16 & 0x00FF0000) +
(attributes[10]<<8 & 0x0000FF00) +
(attributes[11] & 0x000000FF);
assert(datas.getUInt8(pos+5) == 0x01); // Family IPv4 only
port = datas.getUInt16(pos + 6);
address = datas.getUInt32(pos + 8);
break;
}
attributes = attributes + 4 + size;
} // type = 0 or 1
pos += 4 + size;
message_size -= 4 + size;
if (message_size == 0)
return "STUN response is invalid.";
if (message_size < 4) // cannot even read the size
return "STUN response is invalid.";
}
} // while true
// finished parsing, we know our public transport address
Log::debug("GetPublicAddress", "The public address has been found: %i.%i.%i.%i:%i",

4
src/network/protocols/get_public_address.hpp
View File

@ -26,7 +26,7 @@
class GetPublicAddress : public Protocol
{
public:
GetPublicAddress(CallbackObject* callback_object) : Protocol(callback_object, PROTOCOL_SILENT) {}
GetPublicAddress(CallbackObject* callback_object);
virtual ~GetPublicAddress() {}
virtual bool notifyEvent(Event* event) { return true; }
@ -40,7 +40,7 @@ class GetPublicAddress : public Protocol
std::string parseStunResponse();
// Constants
static const uint8_t m_stun_magic_cookie[4];
static const uint32_t m_stun_magic_cookie;
static const int m_stun_server_port = 3478;
enum STATE