HRESULT CStunThreadMessageHandler::ProcessBindingRequest(CStunMessageReader& reader)
{
HRESULT hrTmp;
bool fRequestHasPaddingAttribute = false;
SocketRole socketOutput = _message.localSocket;
StunChangeRequestAttribute changerequest = {};
bool fSendOtherAddress = false;
bool fSendOriginAddress = false;
SocketRole socketOther;
CSocketAddress addrOrigin;
CSocketAddress addrOther;
CStunMessageBuilder builder;
uint16_t paddingSize = 0;
bool fLegacyFormat = false; // set to true if the client appears to be rfc3489 based instead of based on rfc 5789
_spResponseBuffer->SetSize(0);
builder.GetStream().Attach(_spResponseBuffer, true);
fLegacyFormat = reader.IsMessageLegacyFormat();
// check for an alternate response port
// check for padding attribute (todo - figure out how to inject padding into the response)
// check for a change request and validate we can do it. If so, set _socketOutput. If not, fill out _error and return.
// determine if we have an "other" address to notify the caller about
// did the request come with a padding request
if (SUCCEEDED(reader.GetPaddingAttributeSize(&paddingSize)))
{
// todo - figure out how we're going to get the MTU size of the outgoing interface
fRequestHasPaddingAttribute = true;
}
// as per 5780, section 6.1, If the Request contained a PADDING attribute...
// "If the Request also contains the RESPONSE-PORT attribute the server MUST return an error response of type 400."
if (_fRequestHasResponsePort && fRequestHasPaddingAttribute)
{
_error.errorcode = STUN_ERROR_BADREQUEST;
return E_FAIL;
}
// handle change request logic and figure out what "other-address" attribute is going to be
if (SUCCEEDED(reader.GetChangeRequest(&changerequest)))
{
if (changerequest.fChangeIP)
{
socketOutput = SocketRoleSwapIP(socketOutput);
}
if(changerequest.fChangePort)
{
socketOutput = SocketRoleSwapPort(socketOutput);
}
// IsValidSocketRole just validates the enum, not whether or not we can send on it
ASSERT(IsValidSocketRole(socketOutput));
// now, make sure we have the ability to send from another socket
if (_spStunResponder->HasAddress(socketOutput) == false)
{
// send back an error. We're being asked to respond using another address that we don't have a socket for
_error.errorcode = STUN_ERROR_BADREQUEST;
return E_FAIL;
}
}
// If we're only working one socket, then that's ok, we just don't send back an "other address" unless we have all four sockets confgiured
// now here's a problem. If we binded to "INADDR_ANY", all of the sockets will have "0.0.0.0" for an address (same for IPV6)
// So we effectively can't send back "other address" if don't really know our own IP address
// Fortunately, recvfromex and the ioctls on the socket allow address discovery a bit better
fSendOtherAddress = (_spStunResponder->HasAddress(RolePP) && _spStunResponder->HasAddress(RolePA) && _spStunResponder->HasAddress(RoleAP) && _spStunResponder->HasAddress(RoleAA));
if (fSendOtherAddress)
{
socketOther = SocketRoleSwapIP(SocketRoleSwapPort(_message.localSocket));
hrTmp = _spStunResponder->GetSocketAddressForRole(socketOther, &addrOther);
ASSERT(SUCCEEDED(hrTmp));
// so if our ip address is "0.0.0.0", disable this attribute
fSendOtherAddress = (SUCCEEDED(hrTmp) && (addrOther.IsIPAddressZero()==false));
}
// What's our address origin?
VERIFY(SUCCEEDED(_spStunResponder->GetSocketAddressForRole(socketOutput, &addrOrigin)));
if (addrOrigin.IsIPAddressZero())
{
// Since we're sending back from the IP address we received on, we can just use the address the message came in on
// Otherwise, we don't actually know it
if (socketOutput == _message.localSocket)
{
addrOrigin = _message.localAddr;
}
}
fSendOriginAddress = (false == addrOrigin.IsIPAddressZero());
// Success - we're all clear to build the response
_socketOutput = socketOutput;
_spResponseBuffer->SetSize(0);
builder.GetStream().Attach(_spResponseBuffer, true);
builder.AddHeader(StunMsgTypeBinding, StunMsgClassSuccessResponse);
builder.AddTransactionId(_transid);
builder.AddMappedAddress(_message.remoteAddr);
if (fLegacyFormat == false)
{
builder.AddXorMappedAddress(_message.remoteAddr);
}
if (fSendOriginAddress)
{
builder.AddResponseOriginAddress(addrOrigin);
}
if (fSendOtherAddress)
{
builder.AddOtherAddress(addrOther, fLegacyFormat); // pass true to send back CHANGED-ADDRESS, otherwise, pass false to send back OTHER-ADDRESS
}
// finally - if we're supposed to have a message integrity attribute as a result of authorization, add it at the very end
if (_integrity.fSendWithIntegrity)
{
if (_integrity.fUseLongTerm == false)
{
builder.AddMessageIntegrityShortTerm(_integrity.szPassword);
}
else
{
builder.AddMessageIntegrityLongTerm(_integrity.szUser, _integrity.szRealm, _integrity.szPassword);
}
}
builder.FixLengthField();
return S_OK;
}
// The goal of this test is to just validate that we can create a message from CStunMessageBuilder and have it's output parsed correctly by CStunMessageReader
// Also helps validate CSocketAddress
HRESULT CTestBuilder::Test1()
{
HRESULT hr = S_OK;
CStunMessageBuilder builder;
CStunMessageReader reader;
StunAttribute attrib;
CRefCountedBuffer spBuffer;
CRefCountedBuffer spBufferReader;
CSocketAddress addrValidate(0,0);
StunTransactionId transid = {};
uint32_t ipvalidate = 0;
CSocketAddress addr(0x7f000001, 9999);
CSocketAddress addrOrigin(0xAABBCCDD, 8888);
CSocketAddress addrOther(0x11223344, 7777);
ChkA(builder.AddBindingRequestHeader());
ChkA(builder.AddRandomTransactionId(&transid));
ChkA(builder.AddStringAttribute(STUN_ATTRIBUTE_SOFTWARE, "FOOBAR"));
ChkA(builder.AddMappedAddress(addr));
ChkA(builder.AddXorMappedAddress(addr));
ChkA(builder.AddOtherAddress(addrOther));
ChkA(builder.AddResponseOriginAddress(addrOrigin));
ChkA(builder.AddFingerprintAttribute());
ChkA(builder.GetResult(&spBuffer));
ChkIfA(CStunMessageReader::BodyValidated != reader.AddBytes(spBuffer->GetData(), spBuffer->GetSize()), E_FAIL);
ChkIfA(reader.HasFingerprintAttribute() == false, E_FAIL);
ChkIfA(reader.IsFingerprintAttributeValid() == false, E_FAIL);
ChkIfA(reader.GetMessageClass() != StunMsgClassRequest, E_FAIL);
ChkIfA(reader.GetMessageType() != StunMsgTypeBinding, E_FAIL);
ChkA(reader.GetBuffer(&spBufferReader));
ChkA(reader.GetAttributeByType(STUN_ATTRIBUTE_SOFTWARE, &attrib));
ChkIfA(attrib.attributeType != STUN_ATTRIBUTE_SOFTWARE, E_FAIL);
ChkIfA(0 != ::strncmp("FOOBAR", (const char*)(spBufferReader->GetData() + attrib.offset), attrib.size), E_FAIL);
ChkA(reader.GetXorMappedAddress(&addrValidate));
ChkIf(addrValidate.IsSameIP_and_Port(addr) == false, E_FAIL);
ChkIfA(addrValidate.GetIPLength() != 4, E_FAIL);
addrValidate = CSocketAddress(0,0);
ChkA(reader.GetMappedAddress(&addrValidate));
ChkIfA(addrValidate.GetPort() != 9999, E_FAIL);
ChkIfA(addrValidate.GetIPLength() != 4, E_FAIL);
ChkIfA(4 != addrValidate.GetIP(&ipvalidate, 4), E_FAIL);
ChkIfA(ipvalidate != 0x7f000001, E_FAIL);
addrValidate = CSocketAddress(0,0);
ipvalidate = 0;
reader.GetOtherAddress(&addrValidate);
ChkIfA(addrValidate.GetPort() != 7777, E_FAIL);
ChkIfA(addrValidate.GetIPLength() != 4, E_FAIL);
ChkIfA(4 != addrValidate.GetIP(&ipvalidate, 4), E_FAIL);
ChkIf(ipvalidate != 0x11223344, E_FAIL);
Cleanup:
return hr;
}