ipaccess-proxy not relaying traffic to bsc

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Mihai Ordean m.ordean at cs.bham.ac.uk
Mon Oct 29 16:02:46 UTC 2018


Hey all,

First of all let me thanks Neels for his help with the silent_call
problem I've been having, which led me to a successful fix.

Secondly I was wandering if I could get a bit more help with regards to
ipaccess-proxy this time.

Now that silent_call is working I want to start manipulating traffic and
do some fuzzing. I understand that the ipaccess-proxy is the right tool
to use, but I don't seem to get it working.

In my current NON ipaccess-proxy setup (which works) I have an osmo-bts
which gets data from a USRP B210 via osmo-trx-uhd. On the same machine I
also run the osmo-osc. I have configured the OML remote address in the
BTS (bts 0 -> oml remote-ip) to a unique localhost (127.0.127.1) and the
BSC to listen on that (e1_input -> ipa bind 127.0.127.1).

What I want to do is interleave the ipaccess-proxy on this connection
(e.g. receive OML from BTS on 127.0.127.2) and forward to the BSC on
127.0.127.1. I have successfully managed to make ipaccess-proxy bind to
the specific address (by changing the default IP binding from
0.0.0.0:3002 and 0.0.0.0:3003 to 127.0.127.2:3002 and 3003), and I am
receiving traffic from the BTS. However, traffic is never forwarded to
the BSC. There seems to be some issue with unrecognized IPA message types.

Would anyone be able to provide me with some insight, or perhaps a setup
in which ipaccess-proxy worked successfully?

I'm also not clear on what ipaccess-proxy is supposed to do. Is it a
sniffer (since it binds on 0.0.0.0 by default) or is it a "MITM" relay
type of software.

I am attaching the output log I get from ipaccess-proxy.

-- 
Mihai
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[root at cca-132016] ~ # ipaccess-proxy -l 127.0.127.2 -b 127.0.127.1
<0004> ipaccess-proxy.c:927 accept()ed new OML link from 127.0.0.1
<0006> ipaccess-proxy.c:805 unknown RX<-BTS: 00 61 fe 05 00 0a 08 36 30 30 31 2f 30 2f 30 00 00 13 07 62 30 3a 36 65 3a 62 66 3a 33 31 3a 63 32 3a 30 39 00 00 02 02 00 00 0a 03 73 79 73 6d 6f 42 54 53 00 00 02 04 00 00 07 05 30 2e 38 2e 31 00 00 1c 01 73 79 73 6d 6f 42 54 53 2d 62 30 2d 36 65 2d 62 66 2d 33 31 2d 63 32 2d 30 39 00 00 02 00 00
<0006> ipaccess-proxy.c:459 ID_RESP Unit_ID='6001/0/0' MAC_Address='b0:6e:bf:31:c2:09' Location_1='' Location_2='sysmoBTS' Equipment_Version='' Software_Version='0.8.1' Unit_Name='sysmoBTS-b0-6e-bf-31-c2-09' Serial_Number='' <0006> ipaccess-proxy.c:463
<0004> ipaccess-proxy.c:330 (6001/0/0) New BTS connection: Created BTS Conn data structure
<0004> ipaccess-proxy.c:367 (6001/0/0) OML Connected to BSC
<0004> ipaccess-proxy.c:379 (6001/0/0) Created UDP socket for injection towards BTS at port 10100
<0004> ipaccess-proxy.c:391 (6001/0/0) Created UDP socket for injection towards BSC at port 20100
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 01 fe 06
<0006> ipaccess-proxy.c:542 ID_ACK? -> ACK!
<0006> input/ipaccess.c:246 RX 3: 04 01 08 01 07 01 02 01 03 01 04 01 05 01 01 01 00
<0004> input/ipaccess.c:212 Unknown IPA message type
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 00 ff ff ff 24 02 07 00 01 ff 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 01 00 ff ff 24 ff 07 00 01 05 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 f0 00 ff ff 24 ff 07 00 01 05 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 f1 00 ff ff 24 ff 07 00 01 05 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 f2 00 00 ff 24 ff 07 00 01 05 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 f2 00 01 ff 24 01 07 00 01 03 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 02 00 00 ff 24 ff 07 00 01 02 04 02
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 04 00 00 ff 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 00 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 01 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 02 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 03 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 04 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 05 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 06 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 11 ff 80 80 00 0d 61 03 00 00 07 24 ff 07 00 01 02 04 00
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 19 ff 80 80 00 15 62 01 00 ff ff 11 02 43 01 29 03 fa ce 03 00 05 30 2e 35 2e 31
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 19 ff 80 80 00 15 62 01 00 ff ff 11 02 43 01 29 03 fa ce 03 00 05 30 2e 35 2e 31
<0006> ipaccess-proxy.c:805 (6001/0/0) RX<-BTS: 00 19 ff 80 80 00 15 62 01 00 ff ff 11 02 43 01 29 03 fa ce 03 00 05 30 2e 35 2e 31
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