ubuntu-phone team mailing list archive

[Jamie Strandboge <jamie@xxxxxxxxxxxxx>]

On 09/12/2013 05:21 PM, Jamie Strandboge wrote:
> On 08/01/2013 08:23 AM, Jamie Strandboge wrote:
>> On 08/01/2013 05:23 AM, Iain Lane wrote:
>>> On Wed, Jul 31, 2013 at 05:42:43PM +0100, Iain Lane wrote:
>>>> On Wed, Jul 31, 2013 at 03:18:27PM +0400, Alberto Mardegan wrote:
>>>>> On 07/30/2013 07:50 PM, Iain Lane wrote:
>>>>>> Admittedly I didn't know about it ;-) But looking at that API reference
>>>>>> it seems to be more about mobile stuff whereas my question is a bit more
>>>>>> generic than that — I want to know if there's an internet connection of
>>>>>> any type available.
>>>>>>
>>>>>> Maybe I can't see it on this API or maybe Qt has something else for that
>>>>>> in which case I'd be happy to switch over.
>>>>>
>>>>> QNetworkAccessManager::networkAccessible():
>>>>>
>>>>> https://qt-project.org/doc/qt-5.0/qtnetwork/qnetworkaccessmanager.html#networkAccessible-prop
>>>>
>>>> Thanks for the tip. It looks like it should work, however I always get
>>>> QNetworkAccessManager::UnknownAccessibility returned. Is there a trick?
>>>
>>> I found [0] and followed that. Then I get Accessible back. I was happy,
>>> until I tried disconnecting from the network (on my desktop) and still
>>> got Accessible.
>>>
>>> All the while NM has known the correct state, so if I could use that
>>> we'd be in happy land.
>>>
>>> Ho hum?
>>>
>>> [0]
>>> http://www.qtcentre.org/threads/37514-use-of-QNetworkAccessManager-networkAccessible?p=188372#post188372
>>>
>> Along these lines-- we really need to define and document the canonical way for
>> determining network accessibility. My team is tasked with defining apparmor
>> policy for this, and SDK app developers should ideally do this one way and then
>> my team can write tests to make sure that it works for that use case. Everyone
>> coming up with their own method won't work with application confinement.
>>
> I looked into this a bit today. We should *not* rely on anything that uses
> network-manager to obtain this information. Its DBus API does not currently
> provide the answer to "Can I use the internet?" without granting a whole bunch
> of other accesses.
> 
> Instead, apps should use qtdeclarative5-systeminfo-plugin, specifically
> NetworkInfo[1]. I played with this today and rather than talking to
> network-manager, it just reads various files in /sys, /proc and needs 'inet
> stream' and 'inet dgram'. I'll be updating the apparmor policy group for
> 'connectivity' to allow these accesses so it works with
> qtdeclarative5-systeminfo-plugin. I also tested (a bit) with C++ using
> QHostAddress and QNetworkInterface.
> 

Of course, things are never so simple as they seem. The above works fine on
desktop and the Nexus 7, but as soon as ofono is involved (eg, on a Nexus 4),
ofono DBus apparmor denials appear and cause qtdeclarative5-systeminfo-plugin to
report an error. I filed LP: #1226844 to track this.

In the short term there is probably an easy workaround for the bug, bug ideally
we would provide a simple dbus service (I think 'uconnectd' would be a great
name-- feel free to use it ;) with methods like OnlineWired, OnlineWireless and
OnlineCostlyNetwork. Apps would connect to this service (via a small, blessed
QML extension/Qt library) to see if online and this dbus service would in turn
consult network manager and ofono to do the heavy lifting. I imagine it would
take a couple days to design and implement the service, then a couple days for
the qt/qml plugin. CC'ing potentially interested parties.

[1]https://launchpad.net/bugs/1226844

-- 
Jamie Strandboge                 http://www.ubuntu.com/

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