On Wed, 2016-03-16 at 14:53 +0000, Edward Cree wrote:
> On 13/03/16 16:43, Ben Hutchings wrote:
> >
> > On Mon, 2016-02-15 at 14:59 +0000, Edward Cree wrote:
> > >
> > > Signed-off-by: Edward Cree <ec...@solarflare.com>
> > [...]
> > >
> > > @@ -950,6 +1154,19 @@ static int rxclass_get_mask(char *str, unsigned
> > > char *p,
> > > *(__be32 *)&p[opt->moffset] = ~val;
> > > break;
> > > }
> > > + case OPT_IP6: {
> > > + __be32 val[4];
> > > + int i;
> > > + err = rxclass_get_ipv6(str, val);
> > > + if (err)
> > > + return -1;
> > > + for (i = 0; i < 4; i++) {
> > > + ((__be32 *)&p[opt->offset])[i] = val[i];
> > > + if (opt->moffset >= 0)
> > > + ((__be32 *)&p[opt->moffset])[i] = ~val[i];
> > This pointer arithmetic looks terrible. I think memcpy() would be much
> > clearer here.
> I've changed the version in rxclass_get_val to use memcpy() (and memset() the
> mask). Unfortunately, we can't do that here, because we need to complement
> the mask valueas we go, and afaik there's no library function to copy-and-
> complement a byte array.
Sorry, I missed the inversion. But it would still be cleaner to use a
local variable:
__be32 *field = (__be32 *)&p[opt->offset];
> Glibc does, however, have a function memfrob(), which XORs every byte of an
> arraywiththe constant 42. Useful feature, that.
It is!
#include <string.h>
int main(void)
{
char answer;
memset(&answer, 0, 1);
memfrob(&answer, 1);
return answer;
}
> On the other hand, the quoted code is still wrong because it's also writing
> throughopt->offset and checking for opt->moffset>= 0, both daft copy-and-
> paste errors onmypart. Will fix in next version.
> >
> > I won't apply patches labelled as "confidential". You need to stop
> > including this nonsense in your public messages (I thought you fixed
> > this once before).
> In theory it's been fixed harder now - please let me know if not.
Looks like you're sending two copies, one with and one without. Which
works for me, though it might annoy some recipients...
Ben.
--
Ben Hutchings
If you seem to know what you are doing, you'll be given more to do.
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