On 10/27/2014 09:52 AM, Ben Hutchings wrote:
IPv6 does not allow fragmentation by routers, so there is no
fragmentation ID in the fixed header. UFO for IPv6 requires the ID to
be passed separately, but there is no provision for this in the virtio
net protocol.
Until recently our software implementation of UFO/IPv6 generated a new
ID, but this was a bug. Now we will use ID=0 for any UFO/IPv6 packet
passed through a tap, which is even worse.
Unfortunately there is no distinction between UFO/IPv4 and v6
features, so disable UFO on taps and virtio_net completely until we
have a proper solution.
We cannot depend on VM managers respecting the tap feature flags, so
keep accepting UFO packets but log a warning the first time we do
this.
(...)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 186ce54..e8b949a 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -174,7 +174,7 @@ struct tun_struct {
struct net_device *dev;
netdev_features_t set_features;
#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
- NETIF_F_TSO6|NETIF_F_UFO)
+ NETIF_F_TSO6)
int vnet_hdr_sz;
int sndbuf;
@@ -1149,8 +1149,17 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
break;
case VIRTIO_NET_HDR_GSO_UDP:
+ {
+ static bool warned;
one line space after declaration..
+ if (!warned) {
+ warned = true;
+ netdev_warn(tun->dev,
+ "%s: using disabled UFO feature; please fix this program\n",
+ current->comm);
+ }
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
break;
+ }
default:
tun->dev->stats.rx_frame_errors++;
kfree_skb(skb);
@@ -1251,8 +1260,6 @@ static ssize_t tun_put_user(struct tun_struct *tun,
gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (sinfo->gso_type & SKB_GSO_TCPV6)
gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
- else if (sinfo->gso_type & SKB_GSO_UDP)
- gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
else {
pr_err("unexpected GSO type: "
"0x%x, gso_size %d, hdr_len %d\n",
@@ -1762,11 +1769,6 @@ static int set_offload(struct tun_struct *tun, unsigned long arg)
features |= NETIF_F_TSO6;
arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
}
-
- if (arg & TUN_F_UFO) {
- features |= NETIF_F_UFO;
- arg &= ~TUN_F_UFO;
- }
}
/* This gives the user a way to test for new features in future by
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d75256bd..e9e269d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -491,8 +491,16 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
break;
case VIRTIO_NET_HDR_GSO_UDP:
+ {
+ static bool warned;
dto...
+ if (!warned) {
+ warned = true;
+ netdev_warn(dev,
+ "host using disabled UFO feature; please fix it\n");
+ }
skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
break;
+ }
(...)
--
Thanks and Regards,
Varka Bhadram.
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