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Implement a consistent error managing for GetPublicAddress::asynchronousUpdate() by moving the STUN response parsing into its own function

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This commit is contained in:
konstin 2015-08-08 15:03:35 +02:00
parent ee06cd3ba2
commit 5ec9fa38ab
2 changed files with 100 additions and 103 deletions
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198
src/network/protocols/get_public_address.cpp
View File

@ -29,6 +29,8 @@
#include <assert.h>
#include <string>
#ifdef __MINGW32__
# undef _WIN32_WINNT
# define _WIN32_WINNT 0x501
@ -68,6 +70,94 @@ void GetPublicAddress::setup()
m_state = NOTHING_DONE;
}
/**
* Gets the response from the STUN server, checks it for its validity and
* then parses the answer into address and port
* \return "" if the adress could be parsed or an error message
*/
std::string GetPublicAddress::parseResponse()
{
uint8_t* data = m_transaction_host->receiveRawPacket(TransportAddress(m_stun_server_ip, 3478), 2000);
if (!data)
return "STUN response contains no data at all";
// check that the stun response is a response, contains the magic cookie and the transaction ID
if (data[0] != 0x01 ||
data[1] != 0x01 ||
data[4] != (uint8_t)(m_stun_magic_cookie>>24) ||
data[5] != (uint8_t)(m_stun_magic_cookie>>16) ||
data[6] != (uint8_t)(m_stun_magic_cookie>>8) ||
data[7] != (uint8_t)(m_stun_magic_cookie))
{
return "STUN response doesn't contain the magic cookie";
}
if (data[8] != (uint8_t)(m_stun_tansaction_id[0]>>24) ||
data[9] != (uint8_t)(m_stun_tansaction_id[0]>>16) ||
data[10] != (uint8_t)(m_stun_tansaction_id[0]>>8 ) ||
data[11] != (uint8_t)(m_stun_tansaction_id[0] ) ||
data[12] != (uint8_t)(m_stun_tansaction_id[1]>>24) ||
data[13] != (uint8_t)(m_stun_tansaction_id[1]>>16) ||
data[14] != (uint8_t)(m_stun_tansaction_id[1]>>8 ) ||
data[15] != (uint8_t)(m_stun_tansaction_id[1] ) ||
data[16] != (uint8_t)(m_stun_tansaction_id[2]>>24) ||
data[17] != (uint8_t)(m_stun_tansaction_id[2]>>16) ||
data[18] != (uint8_t)(m_stun_tansaction_id[2]>>8 ) ||
data[19] != (uint8_t)(m_stun_tansaction_id[2] ))
{
return "STUN response doesn't contain the transaction ID";
}
Log::verbose("GetPublicAddress", "The STUN server responded with a valid answer");
int message_size = data[2]*256+data[3];
// 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
return "STUN response is too short.";
// Those are the port and the address to be detected
uint16_t port;
uint32_t address;
while(true)
{
int type = attributes[0]*256+attributes[1];
int size = attributes[2]*256+attributes[3];
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);
break;
}
attributes = attributes + 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.";
}
// finished parsing, we know our public transport address
Log::debug("GetPublicAddress", "The public address has been found: %i.%i.%i.%i:%i", address>>24&0xff, address>>16&0xff, address>>8&0xff, address&0xff, port);
TransportAddress* addr = static_cast<TransportAddress*>(m_callback_object);
addr->ip = address;
addr->port = port;
// The address and the port are known, so the connection can be closed
m_state = EXITING;
// terminate the protocol
m_listener->requestTerminate(this);
return "";
}
/** Detects public IP-address and port by first sending a request to a randomly
* selected STUN server and then parsing and validating the response */
void GetPublicAddress::asynchronousUpdate()
@ -151,112 +241,14 @@ void GetPublicAddress::asynchronousUpdate()
freeaddrinfo(res); // free the linked list
}
// Gets the response from the STUN server, checks it for its validity and
// then parses the answer into address and port
if (m_state == TEST_SENT)
{
uint8_t* data = m_transaction_host->receiveRawPacket(TransportAddress(m_stun_server_ip, 3478), 2000);
if (!data)
std::string message = parseResponse();
if (message != "")
{
m_state = NOTHING_DONE; // will send the test again to an other server
return;
Log::warn("GetPublicAddress", "%s", message.c_str());
m_state = NOTHING_DONE;
}
// check that the stun response is a response, contains the magic cookie and the transaction ID
if (data[0] != 0x01 ||
data[1] != 0x01 ||
data[4] != (uint8_t)(m_stun_magic_cookie>>24) ||
data[5] != (uint8_t)(m_stun_magic_cookie>>16) ||
data[6] != (uint8_t)(m_stun_magic_cookie>>8) ||
data[7] != (uint8_t)(m_stun_magic_cookie))
{
return; // invalid data -> try again
}
if (data[8] != (uint8_t)(m_stun_tansaction_id[0]>>24) ||
data[9] != (uint8_t)(m_stun_tansaction_id[0]>>16) ||
data[10] != (uint8_t)(m_stun_tansaction_id[0]>>8 ) ||
data[11] != (uint8_t)(m_stun_tansaction_id[0] ) ||
data[12] != (uint8_t)(m_stun_tansaction_id[1]>>24) ||
data[13] != (uint8_t)(m_stun_tansaction_id[1]>>16) ||
data[14] != (uint8_t)(m_stun_tansaction_id[1]>>8 ) ||
data[15] != (uint8_t)(m_stun_tansaction_id[1] ) ||
data[16] != (uint8_t)(m_stun_tansaction_id[2]>>24) ||
data[17] != (uint8_t)(m_stun_tansaction_id[2]>>16) ||
data[18] != (uint8_t)(m_stun_tansaction_id[2]>>8 ) ||
data[19] != (uint8_t)(m_stun_tansaction_id[2] ))
{
m_state = NOTHING_DONE; // need to re-send the stun request
Log::warn("GetPublicAddress", "The STUN server responded with a invalid answer");
return;
}
Log::verbose("GetPublicAddress", "The STUN server responded with a valid answer");
int message_size = data[2]*256+data[3];
// The stun message is valid, so we parse it now:
bool finish = false;
uint8_t* attributes = data+20;
if (message_size == 0)
{
Log::error("GetPublicAddress", "STUN answer does not contain any information.");
finish = true;
}
if (message_size < 4) // cannot even read the size
{
Log::error("GetPublicAddress", "STUN message is not valid.");
finish = true;
}
// This are the address and port that is wanted
uint16_t port;
uint32_t address;
bool valid = false;
while(!finish)
{
int type = attributes[0]*256+attributes[1];
int size = attributes[2]*256+attributes[3];
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 pack into one 4-byte int
address = (attributes[8]<<24 & 0xFF000000) + (attributes[9]<<16 & 0x00FF0000) + (attributes[10]<<8 & 0x0000FF00) + (attributes[11] & 0x000000FF);
finish = true;
valid = true;
continue;
}
attributes = attributes + 4 + size;
message_size -= 4 + size;
if (message_size == 0)
finish = true;
if (message_size < 4) // cannot even read the size
finish = true;
}
// finished parsing, we know our public transport address
if (valid)
{
Log::debug("GetPublicAddress", "The public address has been found: %i.%i.%i.%i:%i", address>>24&0xff, address>>16&0xff, address>>8&0xff, address&0xff, port);
m_state = ADDRESS_KNOWN;
TransportAddress* addr = static_cast<TransportAddress*>(m_callback_object);
addr->ip = address;
addr->port = port;
}
else
{
Log::error("GetPublicAddress", "STUN message is not valid.");
m_state = NOTHING_DONE; // need to re-send the stun request
}
}
// The address and the port are known, so the connection can be closed
if (m_state == ADDRESS_KNOWN)
{
m_state = EXITING;
// terminate the protocol
m_listener->requestTerminate(this);
}
if (m_state == EXITING)
{
}
}

5
src/network/protocols/get_public_address.hpp
View File

@ -21,6 +21,8 @@
#include "network/protocol.hpp"
#include <string>
class GetPublicAddress : public Protocol
{
public:
@ -46,6 +48,9 @@ class GetPublicAddress : public Protocol
static const uint32_t m_stun_magic_cookie = 0x2112A442;
uint32_t m_stun_server_ip;
STKHost* m_transaction_host;
private:
std::string parseResponse();
};
#endif // GET_PUBLIC_ADDRESS_HPP