Subject: lguest: Don't set impossible combinations of tun features Date: Fri, 13 Jun 2008 14:27:38 +0100 From: Mark McLoughlin If a guest says that it supports e.g. TSO4, but not CSUM, then we blindly try and set this combination of features on the tun iface. However, TUNSETFEATURES will return EINVAL if we pass a senseless combination of features like this. Let's do our best to avoid that. (Fixes misc:tun-gso-csum-features.patch) Signed-off-by: Mark McLoughlin Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index b1997b4..630e159 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -1398,16 +1398,18 @@ static void tun_ring_set_features(struct device *dev) unsigned int features = 0; /* They tell us what they can handle, we tell tun to give it to us. */ - if (has_feature(dev, VIRTIO_NET_F_GUEST_CSUM)) + if (has_feature(dev, VIRTIO_NET_F_GUEST_CSUM)) { features |= TUN_F_CSUM; - if (has_feature(dev, VIRTIO_NET_F_GUEST_TSO4)) - features |= TUN_F_TSO4; - if (has_feature(dev, VIRTIO_NET_F_GUEST_TSO6)) - features |= TUN_F_TSO6; - if (has_feature(dev, VIRTIO_NET_F_GUEST_ECN)) - features |= TUN_F_TSO_ECN; - if (has_feature(dev, VIRTIO_NET_F_HOST_UFO)) - features |= TUN_F_UFO; + if (has_feature(dev, VIRTIO_NET_F_GUEST_TSO4)) + features |= TUN_F_TSO4; + if (has_feature(dev, VIRTIO_NET_F_GUEST_TSO6)) + features |= TUN_F_TSO6; + if (has_feature(dev, VIRTIO_NET_F_GUEST_UFO)) + features |= TUN_F_UFO; + if (features & (TUN_F_TSO4|TUN_F_TSO6) && + has_feature(dev, VIRTIO_NET_F_GUEST_ECN)) + features |= TUN_F_TSO_ECN; + } if (ioctl(dev->fd, TUNSETFEATURES, features) != 0) errx(1, "Could not set features %#x for tun device", features);