unfs3 mount-time password support
=================================

Example exports file:

/tmp (rw,password=gazonk)

Syntax note: The password may contain any character, except
whitespace, comma and right parenthesis.


Mounting with clear-text passwords
----------------------------------

mount yourhost:@password:gazonk/tmp /mnt

Note: When using @password, the password cannot contain slashes. 


Mounting with one-time passwords
--------------------------------

1. Communicate with the mount server and issue a mount for
   "@getnonce". The returned filehandle is your nonce. 

2. Concatenate the nonce with the password, and run it through
   MD5. Convert the result to a hexascii representation. 

3. Example mount command:

mount yourhost:@otp:851d689b11ed4779dd5fbb084b136c52/tmp /mnt

Step 1 and 2 can be done by using the "nfsotpclient" found in the
contrib directory.

Note: With otp:s, a race condition exists. Consider the following:

1) client A requests nonce, gets NA
2) client B requests nonce, gets NB
3) client A sends otp mount using NA
4) client B sends otp mount using NB

Step 3 will not succeed because the server only stores the last
nonce. Step 4 will succeed, though. Client A needs to fetch a new
nonce and retry the mount.