Adding NFS support

2012/05/21 - Achieve connection to a NFSv3 server.
2012/05/30 - Design a SUN ONC RPC layer for iPXE.
- Achieve sending of a NULL query via the RPC layer. A NULL query is like a NO-OP instruction, it can be used to test whether the RPC layer is properly implemented.
2012/06/22 - Get the port of the NFS server and the MOUNT service.
- Achieve connection to a PORTMAP service.
- 2012/06/22 - implement the PORTMAP protocol.
  - 2012/05/30 - Issue a PORTMAP_GETPORT call.
  - 2012/06/22 - Get the PORTMAP_GETPORT reply.
2012/06/25 - Get the root filehandle
- 2012/06/25 - Issue a MNT request to the MOUNT service.
- 2012/06/25 - Parse the MNT reply.
2012/06/27 - Achieve sending of a LOOKUP query via the RPC layer. A LOOKUP query allows one the get a file handle from a path, this handle can then be used to access the file.
- 2012/06/27 - Issue a LOOKUP request to the NFS service
- 2012/06/27 - Parse the LOOKUP reply.
2012/07/01 - Achieve sending of a READ query via the RPC layer. A READ query allows one to get the content of a file by its file handle.
- 2012/06/27 - Issue a READ call to the NFS service
- 2012/07/01 - Get the file content.
2012/07/01 - iPXE is now able to load an image via NFS.
2012/08/06 - Symlinked images can now be downloaded.

Since NFS support has been merged in the main tree, you no longer need to checkout my repository.

Enable NFS support:

  echo "#define DOWNLOAD_PROTO_NFS" >> config/local/general.h

You can now compile iPXE:

  make

URI are in this form:

 nfs://server-address/mountpoint/path/to/file

where path/to/the/file is relative to the mountpoint.