Hi Elise,
On Wed, Dec 07, 2016 at 05:03:31PM -0200, Elise Lennion wrote:
> nft describe displays, to the user, which values are available for a selector,
> then the values should be in host byte order.
>
> Reported-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> Fixes: ccc5da470e76 ("datatype: Replace getnameinfo() by internal lookup table")
> Signed-off-by: Elise Lennion <elise.lennion@xxxxxxxxx>
> ---
>
> v2: Created a function to convert different types and number of bytes
>
> include/datatype.h | 3 ++-
> src/datatype.c | 27 ++++++++++++++++++++++++---
> src/expression.c | 3 ++-
> 3 files changed, 28 insertions(+), 5 deletions(-)
>
> diff --git a/include/datatype.h b/include/datatype.h
> index d4fe817..a7db1df 100644
> --- a/include/datatype.h
> +++ b/include/datatype.h
> @@ -191,7 +191,8 @@ extern struct error_record *symbolic_constant_parse(const struct expr *sym,
> extern void symbolic_constant_print(const struct symbol_table *tbl,
> const struct expr *expr, bool quotes);
> extern void symbol_table_print(const struct symbol_table *tbl,
> - const struct datatype *dtype);
> + const struct datatype *dtype,
> + enum byteorder byteorder);
>
> extern struct symbol_table *rt_symbol_table_init(const char *filename);
> extern void rt_symbol_table_free(struct symbol_table *tbl);
> diff --git a/src/datatype.c b/src/datatype.c
> index b5d73bc..c884171 100644
> --- a/src/datatype.c
> +++ b/src/datatype.c
> @@ -180,15 +180,36 @@ void symbolic_constant_print(const struct symbol_table *tbl,
> printf("%s", s->identifier);
> }
>
> +static void big_to_host_byteorder(void *value, const unsigned int nbytes)
> +{
> + unsigned char *p = value;
> + unsigned int i;
> +
> + for (i = 0; i < nbytes / 2; i++) {
> + p[i] ^= p[nbytes - 1 - i];
> + p[nbytes - 1 - i] ^= p[i];
> + p[i] ^= p[nbytes - 1 - i];
> + }
Sorry, probably I should have specified a bit more.
I suggest you use libgmp for this, that allows any arbitrary word
size. See mpz_init() to initialize the variable, then
mpz_switch_byteorder() to change byteorder. Then, export it via
mpz_export_data() back to fixed standard datatypes.
libgmp is well documented, please have a look at it.
Thanks.
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