This patch is a proof-of-concept I did a few months ago for UDP tunnel
offload support in virtio_net interface, and rebased on to the current
net-next.
Real implementation needs to extend the virtio_net header rather than
piggy-backing on existing fields. Inner MAC length (or inner network
offset) also needs to be passed as a new field. Control plane (QEMU)
also needs to be updated.
All testing was done using Geneve, but this should work for all UDP
tunnels the same.
Signed-off-by: Jarno Rajahalme <ja...@ovn.org>
---
drivers/net/tun.c | 7 ++++-
drivers/net/virtio_net.c | 16 +++++++---
include/linux/skbuff.h | 5 ++++
include/linux/virtio_net.h | 66 ++++++++++++++++++++++++++++++-----------
include/uapi/linux/virtio_net.h | 7 +++++
5 files changed, 78 insertions(+), 23 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 1588469..36f3219 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -198,7 +198,9 @@ 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|NETIF_F_UFO|NETIF_F_GSO_UDP_TUNNEL| \
+ NETIF_F_GSO_UDP_TUNNEL_CSUM| \
+ NETIF_F_GSO_TUNNEL_REMCSUM)
int align;
int vnet_hdr_sz;
@@ -1877,6 +1879,9 @@ static int set_offload(struct tun_struct *tun, unsigned
long arg)
if (arg & TUN_F_UFO) {
features |= NETIF_F_UFO;
+#if 1
+ features |=
NETIF_F_GSO_UDP_TUNNEL|NETIF_F_GSO_UDP_TUNNEL_CSUM|NETIF_F_GSO_TUNNEL_REMCSUM;
+#endif
arg &= ~TUN_F_UFO;
}
}
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ca5239a..eb8d887 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1789,7 +1789,10 @@ static int virtnet_probe(struct virtio_device *vdev)
if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
- | NETIF_F_TSO_ECN | NETIF_F_TSO6;
+ | NETIF_F_TSO_ECN | NETIF_F_TSO6
+ | NETIF_F_GSO_UDP_TUNNEL
+ | NETIF_F_GSO_UDP_TUNNEL_CSUM
+ | NETIF_F_GSO_TUNNEL_REMCSUM;
}
/* Individual feature bits: what can host handle? */
if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
@@ -1798,13 +1801,18 @@ static int virtnet_probe(struct virtio_device *vdev)
dev->hw_features |= NETIF_F_TSO6;
if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
dev->hw_features |= NETIF_F_TSO_ECN;
- if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO)) {
dev->hw_features |= NETIF_F_UFO;
-
+#if 1
+ dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL;
+ dev->hw_features |= NETIF_F_GSO_UDP_TUNNEL_CSUM;
+ dev->hw_features |= NETIF_F_GSO_TUNNEL_REMCSUM;
+#endif
+ }
dev->features |= NETIF_F_GSO_ROBUST;
if (gso)
- dev->features |= dev->hw_features &
(NETIF_F_ALL_TSO|NETIF_F_UFO);
+ dev->features |= dev->hw_features &
(NETIF_F_ALL_TSO|NETIF_F_UFO|NETIF_F_GSO_UDP_TUNNEL|NETIF_F_GSO_UDP_TUNNEL_CSUM|NETIF_F_GSO_TUNNEL_REMCSUM);
/* (!csum && gso) case will be fixed by register_netdev() */
}
if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a4aeeca..992ad30 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2115,6 +2115,11 @@ static inline unsigned char *skb_inner_mac_header(const
struct sk_buff *skb)
return skb->head + skb->inner_mac_header;
}
+static inline int skb_inner_mac_offset(const struct sk_buff *skb)
+{
+ return skb_inner_mac_header(skb) - skb->data;
+}
+
static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
{
skb->inner_mac_header = skb->data - skb->head;
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 1c912f8..17384d1 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -8,10 +8,19 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
const struct virtio_net_hdr *hdr,
bool little_endian)
{
- unsigned short gso_type = 0;
+ u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
+
+ if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+ u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
+
+ if (!skb_partial_csum_set(skb, start, off))
+ return -EINVAL;
+ }
if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
- switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ unsigned short gso_type = 0;
+
+ switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_FLAGS) {
case VIRTIO_NET_HDR_GSO_TCPV4:
gso_type = SKB_GSO_TCPV4;
break;
@@ -27,23 +36,28 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
gso_type |= SKB_GSO_TCP_ECN;
+ if (hdr->gso_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL)
+ gso_type |= SKB_GSO_UDP_TUNNEL;
+ if (hdr->gso_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL_CSUM)
+ gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ if (hdr->gso_type & VIRTIO_NET_HDR_GSO_TUNNEL_REMCSUM) {
+ gso_type |= SKB_GSO_TUNNEL_REMCSUM;
+ skb->remcsum_offload = true;
+ }
+ if (gso_type & (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)) {
+ u16 hdr_len = __virtio16_to_cpu(little_endian,
+ hdr->hdr_len);
+ skb->encapsulation = 1;
+ skb_set_inner_mac_header(skb, hdr_len);
+ skb_set_inner_network_header(skb, hdr_len + ETH_HLEN);
+ /* XXX: What if start is not set? */
+ skb_set_inner_transport_header(skb, start);
+ }
if (hdr->gso_size == 0)
return -EINVAL;
- }
-
- if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
- u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
- u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
-
- if (!skb_partial_csum_set(skb, start, off))
- return -EINVAL;
- }
-
- if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
- u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
-
- skb_shinfo(skb)->gso_size = gso_size;
+ skb_shinfo(skb)->gso_size = __virtio16_to_cpu(little_endian,
+ hdr->gso_size);
skb_shinfo(skb)->gso_type = gso_type;
/* Header must be checked, and gso_segs computed. */
@@ -64,8 +78,8 @@ static inline int virtio_net_hdr_from_skb(const struct
sk_buff *skb,
struct skb_shared_info *sinfo = skb_shinfo(skb);
/* This is a hint as to how much should be linear. */
- hdr->hdr_len = __cpu_to_virtio16(little_endian,
- skb_headlen(skb));
+ u16 hdr_len = skb_headlen(skb);
+
hdr->gso_size = __cpu_to_virtio16(little_endian,
sinfo->gso_size);
if (sinfo->gso_type & SKB_GSO_TCPV4)
@@ -78,6 +92,22 @@ static inline int virtio_net_hdr_from_skb(const struct
sk_buff *skb,
return -EINVAL;
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+ if (sinfo->gso_type & SKB_GSO_UDP_TUNNEL)
+ hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL;
+ if (sinfo->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)
+ hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_CSUM;
+ if (sinfo->gso_type & SKB_GSO_TUNNEL_REMCSUM)
+ hdr->gso_type |= VIRTIO_NET_HDR_GSO_TUNNEL_REMCSUM;
+
+ if (sinfo->gso_type &
+ (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM))
+ /* For encapsulated packets 'hdr_len' is the offset to
+ * the beginning of the inner packet. This way the
+ * encapsulation can remain ignorant of the size of the
+ * UDP tunnel header.
+ */
+ hdr_len = skb_inner_mac_offset(skb);
+ hdr->hdr_len = __cpu_to_virtio16(little_endian, hdr_len);
} else
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index fc353b5..833950b 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -93,7 +93,14 @@ struct virtio_net_hdr_v1 {
#define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */
#define VIRTIO_NET_HDR_GSO_UDP 3 /* GSO frame, IPv4 UDP (UFO) */
#define VIRTIO_NET_HDR_GSO_TCPV6 4 /* GSO frame, IPv6 TCP */
+#define VIRTIO_NET_HDR_GSO_UDP_TUNNEL 0x10 /* GSO frame, UDP tunnel */
+#define VIRTIO_NET_HDR_GSO_UDP_TUNNEL_CSUM 0x20 /* GSO frame, UDP tnl w
CSUM */
+#define VIRTIO_NET_HDR_GSO_TUNNEL_REMCSUM 0x40 /* TUNNEL with TSO & REMCSUM */
#define VIRTIO_NET_HDR_GSO_ECN 0x80 /* TCP has ECN set */
+#define VIRTIO_NET_HDR_GSO_FLAGS (VIRTIO_NET_HDR_GSO_UDP_TUNNEL | \
+ VIRTIO_NET_HDR_GSO_UDP_TUNNEL_CSUM | \
+ VIRTIO_NET_HDR_GSO_TUNNEL_REMCSUM | \
+ VIRTIO_NET_HDR_GSO_ECN)
__u8 gso_type;
__virtio16 hdr_len; /* Ethernet + IP + tcp/udp hdrs */
__virtio16 gso_size; /* Bytes to append to hdr_len per frame */
--
2.1.4
