Sticky load balancing based on tcp socket only (not ip/cookie/http header etc)

Question

I use haproxy for https - the case is quite typical, but I have all requests from one server to many servers, so I have to provide sticky sessions. Unfortunately, the client software doesn't work propely when stickiness is based on cookie. Without haproxy all works well.

Could you recommend me a balancing software which can provide stickiness based on source ip AND port of incoming packets? The idea not to change packets at all even slightly.

Thanks!