On Tue, 2009-11-24 at 12:17 +0100, Pierre Riteau wrote:
> On 24 nov. 2009, at 11:28, Mark McLoughlin wrote:
>
> > On Tue, 2009-11-24 at 10:06 +0100, Pierre Riteau wrote:
> >> vnet_hdr is initialized at 1 by default. We need to reset it to 0 if
> >> the kernel doesn't support IFF_VNET_HDR.
> >>
> >> Signed-off-by: Pierre Riteau <pierre.rit...@irisa.fr>
> >
> > Thanks Pierre, I see why this is needed now
> >
> > Acked-by: Mark McLoughlin <mar...@redhat.com>
> >
> > Cheers,
> > Mark.
>
>
> Thanks for your rapid answer!
>
> BTW, every time I run qemu I see this error message:
>
> TUNSETOFFLOAD ioctl() failed: Invalid argument
>
> It is caused by the piece of code at the end of net/tap-linux.c:
>
> if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
> offload &= ~TUN_F_UFO;
> if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
> fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",
> strerror(errno));
> }
> }
>
> Isn't there a way to detect whether the kernel supports the
> TUNSETOFFLOAD ioctl at all?
The kernel will set errno to EINVAL if TUNSETOFFLOAD isn't supported, so
we could just ignore that case:
if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
offload &= ~TUN_F_UFO;
if (ioctl(fd, TUNSETOFFLOAD, offload) != 0 && errno != EINVAL) {
fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",
strerror(errno));
}
}
The only concern is that we'll also miss out on an error message if
EINVAL is set for another reason. Currently, the only other reason if we
pass a offload flag not supported by the kernel, but that should never
happen.
Feel free to send a patch with that change and I'll ack it
Thanks,
Mark.
