bsc filter: don't ignore imsi-allow on "global" filter level

First off, there are "global" and "local" IMSI black/whitelist levels:

     "global"  "local"
 VTY 'bsc'     'msc'   for osmo-bsc
 VTY 'nat'     'bsc'   for osmo-bsc_nat

Both in osmo-bsc and osmo-bsc-nat, the "global" IMSI filter so far completely
ignores all 'imsi-allow' rules it may contain. A comment in imsi_allow()
proclaims actions that are missing in the code. Notably, in our example config
osmo-bsc_nat.cfg, there is an imsi-allow on the 'nat' level, which with the
code before this patch cannot have been effective in any way.

Furthermore, on the "local" level the order is to check imsi-allow first, and
imsi-deny after that. The comment says to do that in reverse order on the
"global" level. There is no apparent reason for reversing.

Add evaluation of imsi-allow directives on the "global" level, i.e. 'bsc' in
osmo-bsc and 'nat' in osmo-bsc-nat, in the same order as on "local" level, to
avoid confusion. Swap the comment to be consistent.

Before this patch, to have effective imsi-allow, this config would be necessary
for osmo-bsc:

    bsc
     access-list acl imsi-allow 999999999999999
     access-list acl imsi-allow 9017.*
     access-list acl imsi-deny .*
    msc 0
     access-list-name acl
     ...
    msc 1
     access-list-name acl
     ...

With this patch, imsi-allow also works on the "global" level:

    bsc
     access-list acl imsi-allow 999999999999999
     access-list acl imsi-allow 9017.*
     access-list acl imsi-deny .*
     access-list-name acl
    msc 0
     ...
    msc 1
     ...

Change-Id: Idb6c8dd62aa90666ba6fcd213f59d79f5498da3f

0 files changed, 0 insertions, 0 deletions