Cleanup opportunity - mode6 processing

[Hal Murray]

ctl_putsys in ntpd/ntp_control.c is full of things like:
        case CS_MRU_MAXDEPTH:
                ctl_putuint(sys_var[varid].text, mon_data.mru_maxdepth);
                break;

CS_MRU_MAXDEPTH comes from a big line of things like:
#define CS_MRU_MAXDEPTH         30

It is also used in a big table:
        { CS_MRU_MAXDEPTH,      RO, "mru_maxdepth" },   /* 30 */

I think those 3 can be combined into one table.

There are a few non-trivial examples like this:
        case CS_MRU_MAXMEM: {
                uint64_t u;
                u = mon_data.mru_maxdepth * sizeof(mon_entry);
                u = (u+512)/1024;
                ctl_putuint(sys_var[varid].text, u);
                break;
                }
So the table entry needs a wrapper function rather than directly calling 
ctl_putuint.  We may need another wrapper for things like int vs long int.

CS_ROOTDELAY and friends are also used in def_sys_var, a list of variables to 
be returned for some magic name.  I think that can be implemented with a 
flags word.

The above is for system variables.  There is a similar structure for peer 
variables and another for clock variables.

There should be one for auth counters.  I assume the list is in ntpq.  We 
should move it and any similar lists to ntpd so ntpq can print the right 
stuff when talking to a newer or older version of ntpd that has updated the 
set of appropriate counters.



-- 
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