First sketch

diff --git a/src/include/gpxe/netdevice.h b/src/include/gpxe/netdevice.h
new file mode 100644 (file)
index 0000000..3a53ab6
--- /dev/null
+++ b/src/include/gpxe/netdevice.h
@@ -0,0 +1,126 @@
+#ifndef _NETDEVICE_H
+#define _NETDEVICE_H
+
+/** @file
+ *
+ * Net device interface
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/llh.h>
+
+struct net_device;
+struct pk_buff;
+
+/**
+ * A network device
+ *
+ * Note that this structure must represent a generic network device,
+ * not just an Ethernet device.
+ */
+struct net_device {
+       /** Build media-specific link-layer header
+        *
+        * @v netdev    Network device
+        * @v pkb       Packet buffer
+        * @ret rc      Return status code
+        *
+        * This method should convert the packet buffer's generic
+        * link-layer header (a struct gpxehdr) into a media-specific
+        * link-layer header (e.g. a struct ethhdr).  The generic
+        * header should be removed from the buffer (via pkb_pull())
+        * and the media-specific header should be prepended (via
+        * pkb_push()) in its place.
+        *
+        * If a link-layer header cannot be constructed (e.g. because
+        * of a missing ARP cache entry), then this method should
+        * replace the contents of the packet buffer with an
+        * appropriate ARP request or equivalent, and return -ENOENT.
+        */
+       int ( * make_media_header ) ( struct net_device *netdev,
+                                     struct pk_buff *pkb );
+       /** Transmit packet
+        *
+        * @v netdev    Network device
+        * @v pkb       Packet buffer
+        * @ret rc      Return status code
+        *
+        * This method should cause the hardware to initiate
+        * transmission of the packet buffer.  The buffer may be
+        * reused immediately after the method returns, and so the
+        * method should either wait for packet transmission to
+        * complete, or take a copy of the buffer contents.
+        */
+       int ( * transmit ) ( struct net_device *netdev,
+                            struct pk_buff *pkb );
+       /** Poll for received packet
+        *
+        * @v netdev    Network device
+        * @v retrieve  Flag indicating whether or not to retrieve packet
+        * @v pkb       Packet buffer to contain received packet
+        * @ret rc      Return status code
+        *
+        * This method should cause the hardware to check for a
+        * received packet.  If no packet is available, the method
+        * should return -EAGAIN (i.e. this method is *always*
+        * considered to be a non-blocking read).  If a packet is
+        * available, but @c retrieve is false, the method should
+        * return zero for success.  If a packet is available and @c
+        * retrieve is true, the method should fill the packet buffer
+        * and return zero for success.
+        */
+       int ( * poll ) ( struct net_device *netdev, int retrieve,
+                        struct pk_buff *pkb );
+       /** Parse link-layer header
+        *
+        * @v netdev    Network device
+        * @v pkb       Packet buffer
+        * @ret rc      Return status code
+        *
+        * This method should convert the packet buffer's
+        * media-specific link-layer header (e.g. a struct ethhdr)
+        * into a generic link-layer header (a struct gpxehdr).  It
+        * performs the converse function of make_media_header().
+        *
+        * Note that the gpxehdr::addr and gpxehdr::addrlen fields
+        * will not be filled in by this function, since doing so
+        * would require understanding the network-layer header.
+        */
+       int ( * make_generic_header ) ( struct net_device *netdev,
+                                       struct pk_buff *pkb );
+       /** Link-layer protocol
+        *
+        * This is an ARPHRD_XXX constant, in network-byte order.
+        */
+       uint16_t ll_proto;
+       /** Link-layer address length */
+       uint8_t ll_addr_len;
+       /** Link-layer address
+        *
+        * For Ethernet, this is the MAC address.
+        */
+       uint8_t ll_addr[MAX_LLH_ADDR_LEN];
+       /** Driver private data */
+       void *priv;
+};
+
+extern struct net_device static_single_netdev;
+
+/* Must be a macro because priv_data[] is of variable size */
+#define alloc_netdevice( priv_size ) ( {               \
+       static char priv_data[priv_size];               \
+       static_single_netdev.priv = priv_data;  \
+       &static_single_netdev; } )
+
+extern int register_netdevice ( struct net_device *netdev );
+
+static inline void unregister_netdevice ( struct net_device *netdev __unused ){
+       /* Do nothing */
+}
+
+static inline void free_netdevice ( struct net_device *netdev __unused ) {
+       /* Do nothing */
+}
+
+#endif /* _NETDEVICE_H */