Re: [PATCH] GSM SMS reception code

[Marcel Holtmann <marcel holtmann org>]

Hi Dan,

> > > 2) Testcases for PDU decoding; best way to do this is to split out the
> > > bits of the SMS stuff that doesn't depend on anything MM-related like
> > > MMCallbackInfo and whatnot into a separate file, like mm-sms-utils.c or
> > > something, and build that file into libmodem_helpers_la_SOURCES in
> > > Makefile.am.  That makes it easier to link that code to the testcases
> > > without including a bunch of random stuff that isn't related to the unit
> > > tests.  Then we grab a bunch of real-world encoded SMS PDUs and shove
> > > them through the decoder and make sure it works on those, then we can
> > > start fuzzing it too and make sure it's more robust.  We'll really want
> > > testcases as there's quite a bit of variation between devices and
> > > frankly nobody interprets the standards the same way :(
> > 
> > actually the SMS PDUs are pretty much standard since they are
> > transmitted this way over the air.
> > 
> > You are not gonna like this, bu you guys could save yourselves some
> > trouble and just use src/smsutil.c from oFono since we have been through
> > this whole exercise. Including the unit tests actually.
> 
> Probably, yeah.  There's a slight question of licensing since oFono is
> GPLv2 while MM is currently v2+.  Still, it already is implemented in
> oFono and the license thing isn't too big of an issue.

that is what you have to decide since the oFono license is not going to
change any time soon. We did GPLv2 on purpose.

We even saw the FSO project take the oFono SMS implementation and as a
result they had to move from LGPL to GPL.

The oFono SMS implementation is comprehensive and complete since we had
to actually build a phone worthy SMS support with all its gory details.

> > > 4) The whole index thing, figuring out if we can use a generic index
> > > that's MM specific and maps internally to SIM indexes, or whether we can
> > > in fact just use the SIM index...
> > 
> > You are going to enter a world of pain if you are trying to deal with
> > SIM indexes or any kind of indexes for that matter. This whole indexes
> > concept is pretty much ancient from around 1995. Even modern SIM cards
> > are too limited for doing this properly.
> 
> Right, which is why I suggested instead using MM-specific indexes for
> access via the D-Bus API and doing whatever is required internally to
> present a clean external UI.  I believe the indexes in the MM D-Bus API
> should not reference actual SIM messages, but should be synthetic.  I
> don't think it's useful to present each SMS as a D-Bus object, and thus
> indexes are the way to go.  But the indexes should be MM specific,
> transient, and have no relationship to whatever happens inside MM to
> operate on the SMSes.

One thing that you have to decide it where you wanna store the SMS. Is
this storage inside the daemon or better done in the user session.
Either of it is valid choice, only the SIM card is none of them ;)

The only thing that you might wanna consider is that the you actually
wanna have conversations and not random inbox/outbox list with a random
index.

Regards

Marcel