Ccch scan » History » Version 3
laforge, 01/15/2017 01:50 PM
1 | 2 | {{>toc}} |
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2 | 1 | ||
3 | 2 | h1. ccch_scan |
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5 | 2 | ||
6 | The _ccch_scan_ program (formerly layer23) is the playground we use for developing the GSM Protocol layers 2 and 3 (GSM TS 04.05, 04.06, 04.08) |
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8 | 1 | Using the ccch_scan program, you can: |
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9 | 2 | ** Connect to /tmp/osmocom_l2 socket created by [[osmocon]] to exchange data from [[L1A_L23_Interface]]. |
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10 | ** Receive GSM Layer1 frames. |
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11 | *** Dump received GSM Layer1 frames and print some analysis. |
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12 | *** Send the Layer1 frames as [[GSMTAP]] packets to wireshark (see [[WiresharkIntegration]]) |
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13 | *** forward the Layer1 frames to the Layer2 / LAPDm implementation inside ccch_scan |
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14 | *** forward them from Layer2 into Layer3 code inside ccch_scan. |
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15 | ** receive outgoing frames from Layer3 |
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16 | *** process them through layer2 |
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17 | *** send them as uplink frames to [[GSMTAP]] |
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18 | *** send them to the Layer1 on the phone |
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20 | 2 | The _ccch_scan_ program is used in combination with the [[layer1bin]] firmware. |
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22 | 2 | ||
23 | h3. Usage |
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24 | |||
25 | <pre> |
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26 | 1 | ./ccch_scan -a 871 -i 127.0.0.1 |
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27 | 2 | </pre> |
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28 | 1 | ||
29 | 2 | <pre> |
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30 | to which the [[GSMTAP]] messages are to be sent. |
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32 | 2 | This will connect to the [[osmocon]] application and will receive GSM Layer1 frames. |
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33 | 1 | The receiving is done in the src/main.c and the frames will be passed to src/l1ctl.c, |
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34 | from there into src/lapdm.c and finally into src/layer3.c |
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36 | The output of the ccch_scan application is currently looking like this: |
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37 | 2 | <pre> |
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38 | 1 | Found CCCH burst(s): TDMA: (0003/08/39) tc:3 49 06 1b 3b 80 62 f2 20 01 3a c8 07 0a 15 65 04 b9 00 00 80 00 02 1b si: 0x1b |
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39 | SI3 on wrong TC |
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40 | Found sync burst: SNR: 16384 TDMA: (0003/15/46) bsic: 49 |
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41 | Found sync burst: SNR: 16384 TDMA: (0003/25/05) bsic: 49 |
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42 | Found sync burst: SNR: 16384 TDMA: (0003/09/15) bsic: 49 |
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43 | Found sync burst: SNR: 16384 TDMA: (0003/19/25) bsic: 49 |
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44 | Found CCCH burst(s): TDMA: (0003/07/39) tc:4 31 06 1c 62 f2 20 01 3a 65 04 b9 00 00 80 00 53 2b 2b 2b 2b 2b 2b 2b si: 0x1c |
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45 | SI4 on wrong TC |
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46 | Found sync burst: SNR: 16384 TDMA: (0003/14/46) bsic: 49 |
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47 | Found sync burst: SNR: 16384 TDMA: (0003/24/05) bsic: 49 |
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48 | Found sync burst: SNR: 16384 TDMA: (0003/08/15) bsic: 49 |
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49 | Found sync burst: SNR: 16384 TDMA: (0003/18/25) bsic: 49 |
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50 | Found CCCH burst(s): TDMA: (0003/06/39) tc:5 01 06 00 b0 00 58 47 eb 4a 92 53 40 62 84 eb 2b 2b 2b 2b 2b 2b 2b 2b si: 0x0 |
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51 | SI13 on wrong TC |
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52 | 2 | </pre> |