3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Wei-Chun Chao <weichunc@xxxxxxxxxxxx>
[ Upstream commit 7a7ffbabf99445704be01bff5d7e360da908cf8e ]
VM to VM GSO traffic is broken if it goes through VXLAN or GRE
tunnel and the physical NIC on the host supports hardware VXLAN/GRE
GSO offload (e.g. bnx2x and next-gen mlx4).
Two issues -
(VXLAN) VM traffic has SKB_GSO_DODGY and SKB_GSO_UDP_TUNNEL with
SKB_GSO_TCP/UDP set depending on the inner protocol. GSO header
integrity check fails in udp4_ufo_fragment if inner protocol is
TCP. Also gso_segs is calculated incorrectly using skb->len that
includes tunnel header. Fix: robust check should only be applied
to the inner packet.
(VXLAN & GRE) Once GSO header integrity check passes, NULL segs
is returned and the original skb is sent to hardware. However the
tunnel header is already pulled. Fix: tunnel header needs to be
restored so that hardware can perform GSO properly on the original
packet.
Signed-off-by: Wei-Chun Chao <weichunc@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/netdevice.h | 13 +++++++++++++
net/ipv4/gre_offload.c | 11 +++++++----
net/ipv4/udp.c | 6 +++++-
net/ipv4/udp_offload.c | 37 +++++++++++++++++++------------------
4 files changed, 44 insertions(+), 23 deletions(-)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2954,6 +2954,19 @@ static inline void netif_set_gso_max_siz
dev->gso_max_size = size;
}
+static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
+ int pulled_hlen, u16 mac_offset,
+ int mac_len)
+{
+ skb->protocol = protocol;
+ skb->encapsulation = 1;
+ skb_push(skb, pulled_hlen);
+ skb_reset_transport_header(skb);
+ skb->mac_header = mac_offset;
+ skb->network_header = skb->mac_header + mac_len;
+ skb->mac_len = mac_len;
+}
+
static inline bool netif_is_bond_master(struct net_device *dev)
{
return dev->flags & IFF_MASTER && dev->priv_flags & IFF_BONDING;
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -28,6 +28,7 @@ static struct sk_buff *gre_gso_segment(s
netdev_features_t enc_features;
int ghl = GRE_HEADER_SECTION;
struct gre_base_hdr *greh;
+ u16 mac_offset = skb->mac_header;
int mac_len = skb->mac_len;
__be16 protocol = skb->protocol;
int tnl_hlen;
@@ -57,13 +58,13 @@ static struct sk_buff *gre_gso_segment(s
} else
csum = false;
+ if (unlikely(!pskb_may_pull(skb, ghl)))
+ goto out;
+
/* setup inner skb. */
skb->protocol = greh->protocol;
skb->encapsulation = 0;
- if (unlikely(!pskb_may_pull(skb, ghl)))
- goto out;
-
__skb_pull(skb, ghl);
skb_reset_mac_header(skb);
skb_set_network_header(skb, skb_inner_network_offset(skb));
@@ -72,8 +73,10 @@ static struct sk_buff *gre_gso_segment(s
/* segment inner packet. */
enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
segs = skb_mac_gso_segment(skb, enc_features);
- if (!segs || IS_ERR(segs))
+ if (!segs || IS_ERR(segs)) {
+ skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
goto out;
+ }
skb = segs;
tnl_hlen = skb_tnl_header_len(skb);
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2294,6 +2294,7 @@ struct sk_buff *skb_udp_tunnel_segment(s
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
+ u16 mac_offset = skb->mac_header;
int mac_len = skb->mac_len;
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
__be16 protocol = skb->protocol;
@@ -2313,8 +2314,11 @@ struct sk_buff *skb_udp_tunnel_segment(s
/* segment inner packet. */
enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
segs = skb_mac_gso_segment(skb, enc_features);
- if (!segs || IS_ERR(segs))
+ if (!segs || IS_ERR(segs)) {
+ skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
+ mac_len);
goto out;
+ }
outer_hlen = skb_tnl_header_len(skb);
skb = segs;
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -41,6 +41,14 @@ static struct sk_buff *udp4_ufo_fragment
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
unsigned int mss;
+ int offset;
+ __wsum csum;
+
+ if (skb->encapsulation &&
+ skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) {
+ segs = skb_udp_tunnel_segment(skb, features);
+ goto out;
+ }
mss = skb_shinfo(skb)->gso_size;
if (unlikely(skb->len <= mss))
@@ -62,27 +70,20 @@ static struct sk_buff *udp4_ufo_fragment
goto out;
}
+ /* Do software UFO. Complete and fill in the UDP checksum as
+ * HW cannot do checksum of UDP packets sent as multiple
+ * IP fragments.
+ */
+ offset = skb_checksum_start_offset(skb);
+ csum = skb_checksum(skb, offset, skb->len - offset, 0);
+ offset += skb->csum_offset;
+ *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+ skb->ip_summed = CHECKSUM_NONE;
+
/* Fragment the skb. IP headers of the fragments are updated in
* inet_gso_segment()
*/
- if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL)
- segs = skb_udp_tunnel_segment(skb, features);
- else {
- int offset;
- __wsum csum;
-
- /* Do software UFO. Complete and fill in the UDP checksum as
- * HW cannot do checksum of UDP packets sent as multiple
- * IP fragments.
- */
- offset = skb_checksum_start_offset(skb);
- csum = skb_checksum(skb, offset, skb->len - offset, 0);
- offset += skb->csum_offset;
- *(__sum16 *)(skb->data + offset) = csum_fold(csum);
- skb->ip_summed = CHECKSUM_NONE;
-
- segs = skb_segment(skb, features);
- }
+ segs = skb_segment(skb, features);
out:
return segs;
}
--
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