absurd APIs

Some references might to functions with dozens of parameters would help to understand the problem and would enable us to discuss it.

Just check out some of the header files, highlights are:

lib/core/builder.h
lib/core/hashtree.h
firewall/esp_prot_api.h
firewall/user_ipsec_sadb.h (hip_sadb_add() has 19 params!!)
hipd/keymat.h
hipd/user_ipsec_hipd_msg.h
hipd/user_ipsec_sadb_api.h

These are just the public functions, there are some really scary static ones as well...

What's the cut off point of having too many parameters? Multiple parameters could be input as a single structure which embeds all of the parameters. When adding more parameters, this would also cause less changes in the rest of the code.

A word of caution: Grouping parameters in structs only makes sense if these parameters are strongly related. Otherwise the function APIs will have less parameters but the same or higher complexity because absurd structs are used instead.

Sensible grouping, however, will definitely simplify things. Whoever addresses this problem should put some effort into selecting a very good grouping and good naming for it. Discussions here or on the list won't hurt.