[Swan-dev] Use of "struct chunk", "chunk_t", or "chunk_t *" or ...?

[Andrew Cagney]

Hi,

I'm looking to change the "dat/datasize" and "Iv" parameters in:

        void (*do_crypt)(u_int8_t *dat,
                         size_t datasize,
                         PK11SymKey *key,
                         u_int8_t *iv,
                         bool enc);

to chunks.  While the first is somewhat cosmetic, the second ("iv") is
motivated by a bug - for aes_ctr the caller/callee didn't agree on the
length of the parameter named "iv" (ctr calls it counter-block).

To that end I've a few questions:

- is chunk_t or "struct chunk" prefered?
I'm guessing chunk_t but that seems to contradict Chapter 5: Typedefs  in
https://www.kernel.org/doc/Documentation/CodingStyle :-)

- for a parameter, is pass by value (struct chunk) or reference
prefered (struct chunk *)?  My hunch, from looking at lswalloc.h, is
that the preference is for the former as in:

        void (*do_crypt)(struct chunk *data,
                         PK11SymKey *key,
                         struct chunk iv,
                         bool enc);
or:
        void (*do_crypt)(chunk_t dat,
                         size_t datasize,
                         PK11SymKey *key,
                         chunk_t iv,
                         bool enc);

Andrew