[Guy Harris <gharris@xxxxxxxxxxxx>]

> >I.e., the moral equivalent of "ethertype()", but to allow arbitrary
> >dissectors to switch on TCP or UDP ports rather than on Ethernet type?
> 
> The socks protocol needs to call the TCP sub-dissectors but the packet
> doesn't 
> have any TCP header information; so I can't just call the dissect_tcp
> routine.

Which is more or less the same thing that "ethertype()" provides -
"ethertype()" lets you switch on an Ethernet type even if that type
field isn't part of an Ethernet header, and your routines let you switch
on a TCP or UDP port number even if it's not part of a TCP or UDP
header.