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List: ethereal-dev
Subject: RE: [Ethereal-dev] bug report regatding GPRS GTPv1
From: <Michal.Melerowicz () nokia ! com>
Date: 2002-10-28 10:00:44
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You are right, bits 8765 in 3rd octet shouldn't be 0'd. I haven't noticed mistake due \
to one digit MNC I have used to test. Patch should be soon.
Regards, Michal
-----Original Message-----
From: ext ETC WAJU [mailto:etcwaju@hotmail.com]
Sent: Monday, October 28, 2002 2:30 AM
To: ethereal-dev@ethereal.com; jmayer@loplof.de
Cc: etcwaju@hotmail.com
Subject: [Ethereal-dev] bug report regatding GPRS GTPv1
Dear developers
I am here to report a bug I found in Ethereal 0.9.7 regarding GTP v1.
The coding of Information Elemenent IMSI in GTP v1 according to 3GPP 29.060 is as \
follows:
bits 8765 4321
Octects 1 type=2
2~9 IMSI
The IMSI is TBCD-coded with a fixed length of 8 octets. Bits 8765 of octet n+1 \
encodes digit 2n, bits 4321 of octet n+1 encodes digit 2n-1. Unused half octets shall \
be coded as binary "1 1 1 1". Digits are packed contiguously with no internal \
padding.
So for string in the trace which I captured running on GTPv1 "02 13 20 06 02 22 22 00 \
F3"
the IMSI was wrongly decoded as 310060202222003, but it should be decoded as \
310260202222003
The coding of IMSI in GTPv0 according to GSM 03.60
bits 8765 4321
Octects 1 type=2
2 MCC(digit 2) MCC(digit1)
3 1111 MCC(digit3)
4 MNC(digit 2) MCC(digit1)
5 MSN(digit 2) MSN(digit1)
6 MSN(digit 4) MSN(digit3)
7 MSN(digit 6) MSN(digit5)
8 MSN(digit 8) MSN(digit7)
9 MSN(digit 10) MSN(digit9)
So apparently in the above example, GTPv0 decoding was wrongly used to decode IMSI in \
GTPv1 format.
Please feel free to contact me for any questions.
Thanks, JW
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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=591065508-28102002>You
are right, bits 8765 in 3rd octet shouldn't be 0'd. I haven't noticed mistake
due to one digit MNC I have used to test. Patch should be soon.
</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=591065508-28102002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=591065508-28102002>Regards, Michal</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=591065508-28102002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=591065508-28102002></SPAN></FONT> </DIV>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> ext ETC WAJU
[mailto:etcwaju@hotmail.com]<BR><B>Sent:</B> Monday, October 28, 2002 2:30
AM<BR><B>To:</B> ethereal-dev@ethereal.com; jmayer@loplof.de<BR><B>Cc:</B>
etcwaju@hotmail.com<BR><B>Subject:</B> [Ethereal-dev] bug report regatding GPRS
GTPv1<BR><BR></FONT></DIV>
<DIV>
<DIV>
<DIV>
<DIV>Dear developers</DIV>
<DIV> </DIV>
<DIV>I am here to report a bug I found in Ethereal 0.9.7 regarding GTP v1.</DIV>
<DIV><FONT size=2>
<P>The coding of Information Elemenent IMSI in GTP v1 according to 3GPP 29.060
is as follows:</P>
<P>bits \
8765 4321</P>
<P>Octects 1 type=2</P>
<P>
2~9 IMSI</P>
<P>The IMSI is TBCD-coded with a fixed length of 8 octets. Bits 8765 of octet
n+1 encodes digit 2n, bits 4321 of octet n+1 encodes digit 2n-1. Unused half
octets shall be coded as binary "1 1 1 1". Digits are packed contiguously with
no internal padding.</P>
<P>So for string in the trace which I captured running on GTPv1 "02 13 20 06 02
22 22 00 F3"</P>
<P>the IMSI was wrongly decoded as 310060202222003, but it should be decoded as
310260202222003</P>
<P><FONT face=Arial color=#0000ff></FONT> </P>
<P>The coding of IMSI in GTPv0 according to GSM 03.60</P>
<P>bits \
8765 \
4321</P>
<P>Octects 1 type=2</P>
<P> \
2 MCC(digit
2) MCC(digit1)</P>
<P> \
3
1111 \
MCC(digit3)</P>
<P> \
4 MNC(digit
2) MCC(digit1)</P>
<P> \
5 MSN(digit
2) MSN(digit1)</P>
<P> \
6 MSN(digit
4) MSN(digit3)</P>
<P> \
7 MSN(digit
6) MSN(digit5)</P>
<P> \
8 MSN(digit
8) MSN(digit7)</P>
<P> \
9 MSN(digit
10) MSN(digit9)</P>
<P>So apparently in the above example, GTPv0 decoding was wrongly used to decode
IMSI in GTPv1 format.</P>
<P>Please feel free to contact me for any questions.</P>
<P>Thanks, JW</P></FONT></DIV></DIV></DIV></DIV><BR clear=all>
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