How to begin implementing RPC subroutines for NFS V3?

How to begin implementing RPC subroutines for NFS V3?

I have understood the basic structures required for implementing the
subroutines by reading XDR/RPC specifications. I wish to implement
subroutines for lookup,mount,umount,create etc. I don't know how to start.
I have just converted a simple function to an RPC using rpcgen on the
lines of RFC.
I wish to implement the mount function first. Following are the structures
fed to XDR that when compiled with rpcgen generates the client and server
stub and a .h and .c files containing the various declarations.
const MNTPATHLEN = 1024; /* Maximum bytes in a path name */
const MNTNAMLEN = 255; /* Maximum bytes in a name */
const FHSIZE2 = 32; /* Maximum bytes in a V2 file handle */
const FHSIZE3 = 64; /* Maximum bytes in a V3 file handle */
typedef opaque fhandle2[FHSIZE2];
typedef opaque fhandle3<FHSIZE3>;
typedef string dirpath<MNTPATHLEN>;
typedef string name<MNTNAMLEN>;
union fhstatus switch (unsigned fhs_status) {
case 0:
fhandle2 fhs_fhandle;
default:
void;
};
enum mountstat3 {
MNT3_OK = 0, /* no error */
MNT3ERR_PERM = 1, /* Not owner */
MNT3ERR_NOENT = 2, /* No such file or directory */
MNT3ERR_IO = 5, /* I/O error */
MNT3ERR_ACCES = 13, /* Permission denied */
MNT3ERR_NOTDIR = 20, /* Not a directory */
MNT3ERR_INVAL = 22, /* Invalid argument */
MNT3ERR_NAMETOOLONG = 63, /* Filename too long */
MNT3ERR_NOTSUPP = 10004, /* Operation not supported */
MNT3ERR_SERVERFAULT = 10006 /* A failure on the server */
};
/* Structure returned when mount succeeds */
struct mountres3_ok {
fhandle3 fhandle;
int auth_flavors<>;
};
union mountres3 switch (mountstat3 fhs_status) {
case MNT3_OK:
mountres3_ok mountinfo;
default:
void;
};
typedef struct mountbody *mountlist;
/* Mount body */
struct mountbody {
name ml_hostname;
dirpath ml_directory;
mountlist ml_next;
};
typedef struct groupnode *groups;
struct groupnode {
name gr_name;
groups gr_next;
};
typedef struct exportnode *exports;
struct exportnode {
dirpath ex_dir;
groups ex_groups;
exports ex_next;
};
program MOUNT_PROGRAM {
version MOUNT_V1 {
void MOUNTPROC_NULL (void) = 0;
fhstatus MOUNTPROC_MNT (dirpath) = 1;
mountlist MOUNTPROC_DUMP (void) = 2;
void MOUNTPROC_UMNT (dirpath) = 3;
void MOUNTPROC_UMNTALL (void) = 4;
exports MOUNTPROC_EXPORT (void) = 5;
exports MOUNTPROC_EXPORTALL (void) = 6;
} = 1;
version MOUNT_V3 {
void MOUNTPROC3_NULL (void) = 0;
mountres3 MOUNTPROC3_MNT (dirpath) = 1;
mountlist MOUNTPROC3_DUMP (void) = 2;
void MOUNTPROC3_UMNT (dirpath) = 3;
void MOUNTPROC3_UMNTALL (void) = 4;
exports MOUNTPROC3_EXPORT (void) = 5;
} = 3;
} = 100005;
I know that I have to write a function mount() that the server calls when
the client passes in the directory path and the function would probably
contain a call to mount system call. I'm having a hard time visualizing
how to handle different structures such as file handles and return them
appropriately. I'm very stuck. Any insights would be greatly appreciated.
Thank you.