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
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
new file mode 100644
index 0000000..ae469ae
--- /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 */