On Wed, Dec 17, 2014 at 09:43:51PM -0500, Vlad Yasevich wrote:
> On 12/17/2014 05:41 PM, Michael S. Tsirkin wrote:
> > On Wed, Dec 17, 2014 at 01:20:54PM -0500, Vladislav Yasevich wrote:
> >> Now that UFO is split into v4 and v6 parts, we can bring
> >> back v4 support. Continue to handle legacy applications
> >> by selecting the ipv6 fagment id but do not change the
> >> gso type. This allows 2 legacy VMs to continue to communicate.
> >>
> >> Based on original work from Ben Hutchings.
> >>
> >> Fixes: 88e0e0e5aa7a ("drivers/net: Disable UFO through virtio")
> >> CC: Ben Hutchings <[email protected]>
> >> Signed-off-by: Vladislav Yasevich <[email protected]>
> >> ---
> >> drivers/net/macvtap.c | 20 ++++++++++++++------
> >> 1 file changed, 14 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> >> index 880cc09..75febd4 100644
> >> --- a/drivers/net/macvtap.c
> >> +++ b/drivers/net/macvtap.c
> >> @@ -66,7 +66,7 @@ static struct cdev macvtap_cdev;
> >> static const struct proto_ops macvtap_socket_ops;
> >>
> >> #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
> >> - NETIF_F_TSO6)
> >> + NETIF_F_TSO6 | NETIF_F_UFO)
> >> #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
> >> #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG)
> >>
> >> @@ -570,11 +570,14 @@ static int macvtap_skb_from_vnet_hdr(struct sk_buff
> >> *skb,
> >> gso_type = SKB_GSO_TCPV6;
> >> break;
> >> case VIRTIO_NET_HDR_GSO_UDP:
> >> - pr_warn_once("macvtap: %s: using disabled UFO feature;
> >> please fix this program\n",
> >> - current->comm);
> >> gso_type = SKB_GSO_UDP;
> >> - if (skb->protocol == htons(ETH_P_IPV6))
> >> + if (vlan_get_protocol(skb) == htons(ETH_P_IPV6)) {
> >> + /* This is to support legacy appliacations.
> >> + * Do not change the gso_type as legacy apps
> >> + * may not know about the new type.
> >> + */
> >> ipv6_proxy_select_ident(skb);
> >> + }
> >> break;
> >> default:
> >> return -EINVAL;
> >> @@ -619,6 +622,8 @@ static void macvtap_skb_to_vnet_hdr(const struct
> >> sk_buff *skb,
> >> vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
> >> else if (sinfo->gso_type & SKB_GSO_TCPV6)
> >> vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
> >> + else if (sinfo->gso_type & SKB_GSO_UDP)
> >> + vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
> >> else
> >> BUG();
> >> if (sinfo->gso_type & SKB_GSO_TCP_ECN)
> >> @@ -955,6 +960,9 @@ static int set_offload(struct macvtap_queue *q,
> >> unsigned long arg)
> >> if (arg & TUN_F_TSO6)
> >> feature_mask |= NETIF_F_TSO6;
> >> }
> >> +
> >> + if (arg & TUN_F_UFO)
> >> + feature_mask |= NETIF_F_UFO;
> >> }
> >>
> >> /* tun/tap driver inverts the usage for TSO offloads, where
> >> @@ -965,7 +973,7 @@ static int set_offload(struct macvtap_queue *q,
> >> unsigned long arg)
> >> * When user space turns off TSO, we turn off GSO/LRO so that
> >> * user-space will not receive TSO frames.
> >> */
> >> - if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6))
> >> + if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
> >> features |= RX_OFFLOADS;
> >> else
> >> features &= ~RX_OFFLOADS;
> >
> > By the way this logic is completely broken, even without your patch,
> > isn't it?
> >
> > It says: enable LRO+GRO if any of NETIF_F_TSO | NETIF_F_TSO6 |
> > NETIF_F_UFO set.
> >
> > So what happens if I enable TSO only?
> > LRO gets enabled so I can still get TSO6 packets.
> >
> >
> > This really should be:
> >
> > if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO) ==
> > (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)
> >
> >
> > fixing this probably should be a separate patch before your
> > series, and Cc stable.
>
> Actually, all this LRO/GRO feature manipulation on the macvtap device is
> rather pointless as those features aren't really checked at any point
> on the macvtap receive path. GRO calls are done from napi context on
> the lowest device, so by the time a packet hits macvtap, GRO/LRO has
> already been done.
>
> So it doesn't really matter that we disable them incorrectly. I
> can send a separate patch to clean this up.
Hmm so if userspace says it can't handle TSO packets,
it might get them anyway?
> >
> >
> >> @@ -1066,7 +1074,7 @@ static long macvtap_ioctl(struct file *file,
> >> unsigned int cmd,
> >> case TUNSETOFFLOAD:
> >> /* let the user check for future flags */
> >> if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
> >> - TUN_F_TSO_ECN))
> >> + TUN_F_TSO_ECN | TUN_F_UFO))
> >> return -EINVAL;
> >>
> >> rtnl_lock();
> >> --
> >> 1.9.3
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