Decrypt https with libpcap?

I am looking for a library or code snippet or general guidelines for decrypting https traffic from the browser, from the client's point of view (no server access but full client access). I know firefox, for example, supports NSS so that it can remove the ssl key to a file, but how can the libpcap API be used to decrypt https traffic?

This seems like a pretty common question, so I thought I'd ask it here, it might have been covered before so I don't have to reinvent the wheel.

Edit: so in order of words, I would like to have a piece of code or code architecture that helps me decrypt https traffic from tcp packets given the browser master key. Something similar to what wireshark is already doing as described here: https://security.stackexchange.com/questions/35639/decrypting-tls-in-wireshark-when-using-dhe-rsa-ciphersuites

Thank.