Re: ModemManager: Huawei PDU encoded USSD response truncated to 112 characters

[Nathan Williams <njw google com>]

Right, that's my change. Does the USSD path in the plugin know the
length of the text, or does it have to derive the text length from the
length of the hex string? If it doesn't know the length, it's going to
have the same problem I was seeing with SMS messages prior to this
change, where gsm_unpack() couldn't tell if a trailing 7-byte block
had 7 or 8 GSM7 characters in it.

    - Nathan

On Wed, Nov 9, 2011 at 5:48 AM, Graham Inggs <graham inggs uct ac za> wrote:
> I've found that prior to the following commit:
>
> http://cgit.freedesktop.org/ModemManager/ModemManager/commit/src/mm-charsets.c?id=d05c87e4c80f1a56a613241d14de4faeb0a8304a
>
> ...gsm_unpack() in src/mm-charsets.c took the number of encoded characters
> as input, now it takes the number of decoded characters as input.
>
>
> On 07/11/2011 21:50, Graham Inggs wrote:
>>
>> I believe the cause of this problem is that the output string of
>> gsm_unpack() needs to be larger than the input string.  We get 8
>> characters out for every 7 input characters.
>>
>> I have attached a simple patch to /plugins/mm-modem-huawei-gsm.c which
>> results in the full USSD response being returned.
>>
>> I am not sure that this patch is the correct fix.  It may be that
>> gsm_unpack() in src/mm-charsets.c needs take the 8/7 growth into
>> account when sizing the output array and returning the unpacked size.
>> Would someone more familiar with src/mm-charsets.c offer some guidance
>> please?
>>
>>
>> On Fri, Nov 4, 2011 at 8:44 AM, Graham Inggs<graham inggs uct ac za>
>>  wrote:
>>>
>>> Tested with Huawei E1820.
>>>
>>> ussdresult = gsmussd.Initiate("*101#")
>>> print "ussd response: %s" % ussdresult
>>>
>>> ussd response: Balance = R 9.50  Expiry date:02/05/2031.On-Net Minutes
>>> = 01:16:00.Free SMS's = 51.Free Data = 100.00 MB.Free Da
>>>
>>> The full response should have been:
>>>
>>> Balance = R 9.50  Expiry date:02/05/2031.On-Net Minutes =
>>> 01:16:00.Free SMS's = 51.Free Data = 100.00 MB.Free Data = 2007.44 MB.
>>>
>>> Partial ModemManager log:
>>>
>>> modem-manager[3316]:<debug>  [1320384816.466178]
>>> [mm-at-serial-port.c:298] debug_log(): (ttyUSB0): -->
>>> 'AT+CUSD=1,"AA182C3602",15<CR>'
>>> modem-manager[3316]:<debug>  [1320384816.504610]
>>> [mm-at-serial-port.c:298] debug_log(): (ttyUSB0):<--
>>> '<CR><LF>OK<CR><LF>'
>>> modem-manager[3316]:<debug>  [1320384816.818950]
>>> [mm-at-serial-port.c:298] debug_log(): (ttyUSB2):<--
>>> '<CR><LF>^RSSI:16<CR><LF>'
>>> modem-manager[3316]:<debug>  [1320384816.819316]
>>> [mm-at-serial-port.c:298] debug_log(): (ttyUSB2):<--
>>> '<CR><LF>^CSNR:-77,-7<CR><LF>'
>>> modem-manager[3316]:<debug>  [1320384818.431324]
>>> [mm-at-serial-port.c:298] debug_log(): (ttyUSB2):<-- '<CR><LF>+CUSD:
>>>
>>> 0,"C2303BEC1E97413D90149473D5602050110F4FCBF32072985ED6C1642F58ED2583CD62AEA7BBE52CD341CDB4BB4E2FCF413D102CA68BD9743098CB282F9741D3E6F43407F540B598CB282F9741C4303D0CEA816230980B060335852EA3BC5C0611C3F430A80792C16037178D066A0A5D",15<CR><LF>'
>>>
>
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