How to call dissector for IPv6 next header

edit

I am working on a Lua dissector for a new IPv6 hop-by-hop extension header we are developing in the IETF. See: https://tools.ietf.org/html/draft-hin...

I have gotten it to work to parse and display the header, but I don't know how to call the next dissector. It can be any IP protocol (TCP/UDP/etc.) as defined in https://www.iana.org/assignments/prot....

I can get it to work in a test case for UDP by using a static value:

     Dissector.get("udp"):call(buffer(aoptionlen):tvb(), pinfo, tree)

inside the function. How do I do this for the general case? I have the next header value in a variable.

Thanks in advance.

Bob