void StandardInMessage::doChecksum()
{
auto givenChecksum = getU32();
auto size = getRemainingSize();
if(givenChecksum != crypto::adler32(peekRawChunckAs<uint8_t>(size), size))
throw PacketException();
}
boost::asio::mutable_buffers_1 StandardInMessage::parseHeaderAndGetBodyBuffer()
{
auto bodySize = getU16();
// 8 = adler + 1 xtea frame smallest packet
if(bodySize < 8 || bodySize > STANDARD_IN_MESSAGE_MAX_BODY_SIZE)
throw PacketException();
setRemainingSize(bodySize);
return getBodyBuffer();
}
void StandardInMessage::xteaDecrypt(const crypto::Xtea& xtea)
{
auto size = getRemainingSize();
if(size%8 != 0)
throw PacketException();
xtea.decrypt(peekRawChunckAs<uint32_t>(size), size);
setRemainingSize(getU16());
}
// for a given destination address - return the local endpoint address and the gateway address that
// will be used for a connection to the destination.
// if the local address and the gateway address are the same then the destination is on a local network.
void getRouteInfo (net::InetAddress destination, net::InetAddress& localAddr, net::InetAddress& gatewayAddr)
{
MIB_IPFORWARDROW routeInfo;
DWORD res = GetBestRoute(htonl(destination.getIPAddress()), 0, &routeInfo);
if (res != NO_ERROR)
throw PacketException ("getRouteInfo: Error");
gatewayAddr.set(ntohl(routeInfo.dwForwardNextHop), 0);
destination.setPortNumber(123);
net::Socket s(SOCK_DGRAM);
s.connect(destination);
localAddr = s.getLocalAddress();
}