tree 1a6ebd49ac504547610171d0fcd0cc221f697cb0
parent 234f9cb701c83a85ccbfbfb904aa04d87662bdc5
author Neels Hofmeyr <neels@hofmeyr.de> 1508198304 +0200
committer Neels Hofmeyr <neels@hofmeyr.de> 1509064549 +0200

ctrl: completely replace all CTRL commands

The previous commands are not conforming to how the CTRL interface is intended
to work:

  SET enable-ps <IMSI>
  SET disable-ps <IMSI>
  SET status-ps <IMSI>

'status-ps' is a write-only command even though it returns the status.
'enable-ps' / 'disable-ps' indicate the value instead of a variable name of an
entity. The entity <IMSI> takes the place of the variable value.

See also https://lists.osmocom.org/pipermail/openbsc/2017-September/011236.html

Instead, replace with

  SET subscriber.by-imsi-123456.ps-enabled {0,1}
  GET subscriber.by-imsi-123456.ps-enabled

and also provide further CTRL functions while at it:

  {SET,GET} subscriber.by-{imsi,msisdn,id}-123456.{cs,ps}-enabled {0,1}
  GET subscriber.by-{imsi,msisdn,id}-123456.{info,info-aud,info-all}

Provide CTRL tests in the form of transcripts.

Adjust tests/test_subscriber.sql to feature nonzero SQN, to see some values for
SQN in the CTRL transcript tests. (This does not affect the VTY tests, because
that creates its own subscribers, and there's no VTY command to set the SQN.)

This is the first time an application uses CTRL_NODE ids that are defined
outside of libosmocore, see 'Depends' below.

Implementation choice: the first idea was to have a '.' between the 'by-xxx'
and the value, like:

  subscriber.by-xxx.123456.function

but the difficulty with subscribers is that they are not in RAM, and I can't
just point node_data at a struct instance that is always there (like, say, a
global bts[0] struct in osmo-bsc). Instead, I want to store the selector and
later decide whether to read from the DB or whatever. With a '.' separating
things, the only way in a ctrl function to obtain both 'by-xxx' and '123456'
for picking a subscriber record would be to parse the entire variable path
string elements, including 'subscriber' and 'function', which would then also
clumsily fix at which node level we hook these commands; there could have been
separate CTRL_NODE_SUBSCR_BY_{IMSI,MSISDN,ID} parent nodes, but we cannot
introspect the current parent node dynamically within a ctrl function handler
(plus I'm not sure whether it's possible and a good idea to have the same
command under multiple parent nodes).

Rather than that, I store the 'by-foo-123' token in the node_data pointer to
have both bits of information pointed at by a single pointer; I use the
incoming command parsing to get this token pre-separated from surrounding node
names, and no need to re-allocate it, since the vector of tokens lives until
after command execution is complete. Each leaf command obtains this token from
cmd->node (aka node_data), and feeds this token to a common static function to
parse selector and value from it and to retrieve a subscriber record as needed.

(BTW, I have mentioned on the mailing list that this way might be necessary to
avoid numeric-only CTRL node names, but we don't need to, and that is not at
all related to this choice of structure.)

Depends: libosmocore I1bd62ae0d4eefde7e1517db15a2155640a1bab58
         libosmocore Ic9dba0e4a1eb5a7dc3cee2f181b9024ed4fc7005
Change-Id: I98ee6a06b3aa6a67adb868e0b63b0e04eb42eb50