iSCSI: session login and ISID

[sandeepj@research.bell-labs.com (Sandeep Joshi)]

There seems to be a problem in distinguishing session logins, using 
only the ISID field in the Login Command.   It is possible that 
different initiators could try to start a session using the same ISID 
value.   One of those attempts will get rejected, since the ISID is 
the sole key to find if a session already exists. (note: TSID was 
sent as zero for the leading connection of session)

The initiator WWUI does not seem to be available at this time.
a) Appendix D.10 states that InitiatorWWUI is optional and defaults
   to iSCSI.
b) Section 2.10.9 on Login Command states that "initiator MAY provide 
   some basic parameters".

On the other hand, Section 1.2.7 states that "the initiator MUST
present both its initiator WWUI and target WWUI to which it wishes
to connect during the login phase".

The WWUI is also needed if we are to support multiple I_T nexuses 
between the same initiator and target.  

So it seems like Section 1.2.7 has the right spec.   Appendix D and 
Section 2.10.9 must then be corrected.  The descriptions in Sec 4.1 
and Section 1.2.3 may also need to be changed to reflect the fact 
that initiator WWUI must be supplied at session login.

-Sandeep