Can somebody weigh in on the feasiblity of cracking Diffie Helman? In Cryptography Engineering, Schneir et al say "there is no known formula" for computing x &

Can somebody weigh in on the feasiblity of cracking Diffie Helman? In Cryptography Engineering, Schneir et al say "there is no known formula" for computing x & y -- but this is a different kind of problem than ciphers, and a suitably advanced mathematical formula could potentially be discovered. It seems to me that the NSA are probably pretty advanced when it comes to prime number mathematics, and it's highly likely that they have teams of cryptographers chasing exactly such a formula.