On Thu, 2006-06-08 at 17:15 +1000, Herbert Xu wrote:
> Andy Gay <andy@xxxxxxxxxxx> wrote:
> >
> > The policy print errors can be fixed by this patch (this is against
> > iproute2-2.6.16-060323):
> > # diff -u --show-c-function xfrm_policy.c~ xfrm_policy.c
> > --- xfrm_policy.c~ 2005-11-07 13:39:30.000000000 -0500
> > +++ xfrm_policy.c 2006-06-07 18:29:13.000000000 -0400
> > @@ -362,7 +362,7 @@ int xfrm_policy_print(const struct socka
> > } else {
> > xpexp = NULL;
> > xpinfo = NLMSG_DATA(n);
> > - len -= NLMSG_LENGTH(sizeof(*xpinfo));
> > + len -= NLMSG_LENGTH(NLMSG_ALIGN(sizeof(*xpinfo)));
> > }
> >
> > if (len < 0) {
>
> A shorter way to write this is
>
> len -= NLMSG_SPACE(sizeof(*xpinfo);
>
Yes, that works as well (I tried it!). Interesting... My patch was using
a construction of the form
NLMSG_LENGTH(NLMSG_ALIGN(len))
while the first level expansion of NLMSG_SPACE(len) is
NLMSG_ALIGN(NLMSG_LENGTH(len))
Since it works both ways, it appears NLMSG_ALIGN and NLMSG_LENGTH can be
used in either order. Is that guaranteed, I wonder?
> Cheers,
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