[HECnet] PyDECnet setup

Some possibilities, based on VERY cursory analysis. "zero counters" should be straightforward. Adding and removing node entries (for remote nodes) also should be straightforward. Circuit state (on/off) is a bit of work because routing gets involved -- a circuit that is off doesn't reach anyone and can't have route vector messages sent to it. Changing circuit or executor parameters may be easy or not, it depends on the parameter. For example, executor parameter max cost is not hard; max nodes is much harder because some routing data structures are built based on that value. The same, only more so, applies to executor address and type. Similarly, for changing circuit parameters the answer is also "it depends". Creating new circuits (additional circuits) may not be as hard as I thought. It's difficult as a NICE operation since many of the configuration parameters in the config file are non-DECnet things like IP addresses and circuit emulation protocols. But that's what OS-dependent parameters are for :-). That also implies that it might be possible to read those settings; right now they aren't visible. I had thought of adding them to the web interface (with an ability to suppress that if desired); hadn't thought of NICE but the same reasoning applies there. As for access control, PyDECnet already supports username/password checking, so NICE "modify" actions can be tied to an ACL that specifies the user names permitted to do this. By default that might be just "root". So if you connect to NICE with the username of a permitted user and the correct password for that user, the PAM module would approve those credentials and then that would let you do the operation. paul