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Le 8 mai 2016 23:22, "reginaldo salles" <reginaldosalles1972@xxxxxxxxx> a écrit :
>>
>> It has been ages since I last looked at GSM logs, but as far as I can tell this capture does not contain any audio samples but only control plane messages.
>
> Hi Pascal, thanks to your help. This capture contains a call that i made inbound my test BTS. I activate the GSMTAP interface at loopback and direct capture all traffic using tshark.
> The command that i used is: tshark -i lo -f "port 4729" -w /call.cap
>
I'm still surprised by the LAPDm captures as it looks like not all packets are present (it does not follow what I can remember from 3GPP 24.006).
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>> By the way you have not answered my previous questions regarding the way those captures are done and whether some LAPDm packets were filtered or not.
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> I dont have any filter or firewall activates and i can direct capture any packet in my test environment, so i can help you if you need any information.
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> Im trying to figure out a way to capture the CALL (audio) between phones in my test environment. I dont activate any encryption and my bts is based in YateBTS.
Looks like your equipment does not allow capturing HR/FR/AMR packets. I'm not a YateBTS user so I cannot tell you more. Better ask to the guys responsible for this project instead.
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> Your patch works fine and i due to your patch i can read the SMS in plain text. Anyway, if i activate the tshark like above, i can get the sms correctly (withou need your patch). But if i activate the tshark using: tshark -i lo -w /call.cap i cant see the SMS, just a error related to missing PDU or missing packet.
My patch is required if:
- you capture ICMP error packets (with you can filter with a capture filter), or
- you have LAPDm retransmissions (that you cannot filter so it's simply a question of luck)
Still my patch does not work as good as it could due to the inconsistent N(S) increment seen in the capture.
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>>
>>
>> Regards,
>> Pascal.
>
>
> One more time thanks to all. if you can, send me details about GSM call and how i can capture it correctly and play the captured audio.
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>> PS: the SIB13 malformed packet error seen is fixed in https://code.wireshark.org/review/#/c/15290
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>>
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