Switch from a rake-based build to a make-based build.

This commit beefs up the Makefile to do the build, instead of the
Rakefile.

It also removes from the Rakefile the dependency on rake_utils, which
should mean it's ok to build in a schroot.

The files are reorganised to make the Makefile rules more tractable,
although the reorganisation reveals a problem with our current code
organisation.

The problem is that the proxy-specific code transitively depends on the
server code via flexnbd.h, which has a circular dependency on the server
and client structs. This should be broken in a future commit by
separating the flexnbd struct into a shared config struct and
server-specific parts, so that the server code can be moved into
src/server to more accurately show the functional dependencies.

src/common/nbdtypes.h

@@ -0,0 +1,85 @@
+#ifndef __NBDTYPES_H
+#define __NBDTYPES_H
+
+
+/* http://linux.derkeiler.com/Mailing-Lists/Kernel/2003-09/2332.html */
+#define INIT_PASSWD "NBDMAGIC"
+#define INIT_MAGIC 0x0000420281861253
+#define REQUEST_MAGIC 0x25609513
+#define REPLY_MAGIC 0x67446698
+#define REQUEST_READ 0
+#define REQUEST_WRITE 1
+#define REQUEST_DISCONNECT 2
+
+/* The top 2 bytes of the type field are overloaded and can contain flags */
+#define REQUEST_MASK 0x0000ffff
+
+
+/* 1MiB is the de-facto standard for maximum size of header + data */
+#define NBD_MAX_SIZE ( 1024 * 1024 )
+
+#define NBD_REQUEST_SIZE ( sizeof( struct nbd_request_raw ) )
+#define NBD_REPLY_SIZE   ( sizeof( struct nbd_reply_raw ) )
+
+#include <linux/types.h>
+#include <inttypes.h>
+
+/* The _raw types are the types as they appear on the wire.  Non-_raw
+ * types are in host-format.
+ * Conversion functions are _r2h_ for converting raw to host, and _h2r_
+ * for converting host to raw.
+ */
+struct nbd_init_raw {
+	char passwd[8];
+	__be64 magic;
+	__be64 size;
+	char reserved[128];
+};
+
+struct nbd_request_raw {
+	__be32 magic;
+	__be32 type;    /* == READ || == WRITE  */
+	char handle[8];
+	__be64 from;
+	__be32 len;
+} __attribute__((packed));
+
+struct nbd_reply_raw {
+	__be32 magic;
+	__be32 error;           /* 0 = ok, else error   */
+	char handle[8];         /* handle you got from request  */
+};
+
+
+
+struct nbd_init {
+	char passwd[8];
+	uint64_t magic;
+	uint64_t size;
+	char reserved[128];
+};
+
+struct nbd_request {
+	uint32_t magic;
+	uint32_t type;    /* == READ || == WRITE || == DISCONNECT */
+	char handle[8];
+	uint64_t from;
+	uint32_t len;
+} __attribute__((packed));
+
+struct nbd_reply {
+	uint32_t magic;
+	uint32_t error;           /* 0 = ok, else error   */
+	char handle[8];         /* handle you got from request  */
+};
+
+void nbd_r2h_init( struct nbd_init_raw * from, struct nbd_init * to );
+void nbd_r2h_request( struct nbd_request_raw *from, struct nbd_request * to );
+void nbd_r2h_reply( struct nbd_reply_raw * from, struct nbd_reply * to );
+
+void nbd_h2r_init( struct nbd_init * from, struct nbd_init_raw * to);
+void nbd_h2r_request( struct nbd_request * from, struct nbd_request_raw * to );
+void nbd_h2r_reply( struct nbd_reply * from, struct nbd_reply_raw * to );
+
+#endif
+