Net driver using virtio

The network driver uses two virtqueues: one for input packets and one
for output packets.  This has nice locking properties (ie. we don't do
any for recv vs send).

TODO:
	1) Big packets.
	2) Multi-client devices (maybe separate driver?).
	3) Resolve freeing of old xmit skbs (Christian Borntraeger)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org

2 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index e5208f283a67..b101588a4b5a 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -344,6 +344,7 @@ unifdef-y += utsname.h
 unifdef-y += videodev2.h
 unifdef-y += videodev.h
 unifdef-y += virtio_config.h
+unifdef-y += virtio_net.h
 unifdef-y += wait.h
 unifdef-y += wanrouter.h
 unifdef-y += watchdog.h
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
new file mode 100644
index 000000000000..ae469ae55d36
--- /dev/null
+++ b/include/linux/virtio_net.h
@@ -0,0 +1,36 @@
+#ifndef _LINUX_VIRTIO_NET_H
+#define _LINUX_VIRTIO_NET_H
+#include <linux/virtio_config.h>
+
+/* The ID for virtio_net */
+#define VIRTIO_ID_NET   1
+
+/* The bitmap of config for virtio net */
+#define VIRTIO_CONFIG_NET_F     0x40
+#define VIRTIO_NET_F_NO_CSUM    0
+#define VIRTIO_NET_F_TSO4       1
+#define VIRTIO_NET_F_UFO        2
+#define VIRTIO_NET_F_TSO4_ECN   3
+#define VIRTIO_NET_F_TSO6       4
+
+/* The config defining mac address. */
+#define VIRTIO_CONFIG_NET_MAC_F 0x41
+
+/* This is the first element of the scatter-gather list.  If you don't
+ * specify GSO or CSUM features, you can simply ignore the header. */
+struct virtio_net_hdr
+{
+#define VIRTIO_NET_HDR_F_NEEDS_CSUM     1       // Use csum_start, csum_offset
+      __u8 flags;
+#define VIRTIO_NET_HDR_GSO_NONE         0       // Not a GSO frame
+#define VIRTIO_NET_HDR_GSO_TCPV4        1       // GSO frame, IPv4 TCP (TSO)
+/* FIXME: Do we need this?  If they said they can handle ECN, do they care? */
+#define VIRTIO_NET_HDR_GSO_TCPV4_ECN    2       // GSO frame, IPv4 TCP w/ ECN
+#define VIRTIO_NET_HDR_GSO_UDP          3       // GSO frame, IPv4 UDP (UFO)
+#define VIRTIO_NET_HDR_GSO_TCPV6        4       // GSO frame, IPv6 TCP
+      __u8 gso_type;
+      __u16 gso_size;
+      __u16 csum_start;
+      __u16 csum_offset;
+};
+#endif /* _LINUX_VIRTIO_NET_H */