Merge pull request #19 from racerxdl/limebts

Add LimeSDR Network In a Box tutorial

docs/radiofrequency/limesdr-bts.md

@@ -0,0 +1,457 @@
+# GSM Network: LimeSDR
+
+**DISCLAIMER**: This procedure is highly illegal basically anywhere in the world. Be sure to run this in a closed RF environment (also know as Faraday Cage)
+
+
+* [Running a GSM Station with osmo network-in-a-box (sms/audio)](#running-a-gsm-station-with-osmo-network-in-a-box)
+* Running a GSM Station with full osmo (sms/audio/data) [TODO]
+
+
+### Running a GSM Station with osmo network-in-a-box
+
+For this example we will use the Osmocom GSM Stack in the NITB (Network in the box) mode. In this mode the phones connected to you BTS will be able to call each other and send SMS messages. There is also the Interconnect mode in which the BSC (Base Station Controller) connects to a ISDN or IPBX (for example Asterisk) to manage the connected phones. You can check the different modes here: [https://osmocom.org/projects/openbsc/wiki/OpenBSC#Configurations-Modes](https://osmocom.org/projects/openbsc/wiki/OpenBSC#Configurations-Modes)
+
+For this article I will be using a Ubuntu 18.04 LTS as operating system since there are pre-compiled packages from [LimeMicro](https://limemicro.com/) that helps a lot. It should run in any linux distribution provided that it has the required packages and / or you compile the missing ones. I might make a tutorial later about how to install from the source code but for now I will stick to the pre-compiled packages.
+
+## Installing the required packages
+
+The first thing we need to do is to install all required packages. LimeMicro did a nice work and gathered everything pre compiled in their PPAs. So let’s add them first:
+
+```bash
+sudo add-apt-repository -y ppa:myriadrf/drivers
+sudo add-apt-repository -y ppa:myriadrf/gnuradio
+```
+
+Let’s also add the osmocom binary builds:
+
+```bash
+wget https://download.opensuse.org/repositories/network:/osmocom:/latest/xUbuntu_18.04/Release.key
+sudo apt-key add Release.key
+rm Release.key
+echo "deb [https://download.opensuse.org/repositories/network:/osmocom:/latest/xUbuntu_18.04/](https://download.opensuse.org/repositories/network:/osmocom:/latest/xUbuntu_18.04/) ./" | sudo tee /etc/apt/sources.list.d/osmocom-latest.list
+sudo apt-get update
+```
+
+Then we can install required packages:
+
+```bash
+sudo apt install osmocom-nitb osmo-trx-lms osmo-bts-trx limesuite
+```
+
+These packages are:
+
+* `osmocom-nitb` => Network in a Box Package. Contains all needed stuff for managing GSM Network
+* `osmo-bts-trx` => The Base Transceiver Station software that manages how the network packets will be sent.
+* `osmo-trx-lms` => The LimeSDR “frontend” for the BTS. This is the piece of software that actually communicates with LimeSDR
+* `limesuite` => The software and driver for the LimeSDR
+
+## Updating the LimeSDR Firmware
+
+It is a good pratice to check if your LimeSDR firmware is up to date. To check and update if needed, you only need to run:
+
+```bash
+LimeUtil --update
+```
+
+It should do everything that is needed to update
+
+## Creating the configuration files
+
+There are few files that need to be created. Let’s first start with the OpenBSC config file *openbsc.cfg*:
+
+```
+!
+! OpenBSC configuration saved from vty
+!   !
+password foo
+!
+line vty
+ no login
+!
+e1_input
+ e1_line 0 driver ipa
+network
+ network country code 901
+ mobile network code 70
+ short name HUEHUE
+ long name HUEBRNetwork
+ auth policy accept-all
+ location updating reject cause 13
+ encryption a5 0
+ neci 1
+ rrlp mode none
+ mm info 1
+ handover 0
+ handover window rxlev averaging 10
+ handover window rxqual averaging 1
+ handover window rxlev neighbor averaging 10
+ handover power budget interval 6
+ handover power budget hysteresis 3
+ handover maximum distance 9999
+ bts 0
+  type sysmobts
+  band GSM900
+  cell_identity 0
+  location_area_code 1
+  training_sequence_code 7
+  base_station_id_code 63
+  ms max power 15
+  cell reselection hysteresis 4
+  rxlev access min 0
+  channel allocator ascending
+  rach tx integer 9
+  rach max transmission 7
+  ip.access unit_id 1801 0
+  oml ip.access stream_id 255 line 0
+  gprs mode none
+  trx 0
+   rf_locked 0
+   arfcn 100
+   nominal power 23
+   max_power_red 20
+   rsl e1 tei 0
+   timeslot 0
+    phys_chan_config CCCH+SDCCH4
+   timeslot 1
+    phys_chan_config SDCCH8
+   timeslot 2
+    phys_chan_config TCH/F
+   timeslot 3
+    phys_chan_config TCH/F
+   timeslot 4
+    phys_chan_config TCH/F
+   timeslot 5
+    phys_chan_config TCH/F
+   timeslot 6
+    phys_chan_config TCH/F
+   timeslot 7
+    phys_chan_config TCH/F
+```
+There are several parameters here, but I will only describe the ones you might want to change:
+
+```
+network country code 901
+mobile network code 70
+short name HUEHUE
+long name HUEBRNetwork
+auth policy accept-all
+```
+
+* `network country code` => That is the MCC of the network operator. It says in which country the operator is operating. For example: 724 is Brazil
+* `mobile network code` => That is the MNC of the network operator. It says which network operator it is. Every mobile network operator has its own MNC (some of them have more than one).
+* `short name` => The Short name of the network operator
+* `long name` => The Long Name of the network operator
+* `auth policy` => How we will accept the phones that are trying to connect.
+
+Be careful setting these settings specially with a **accept-all** policy. If you set to an existing mobile operator, any phone that is close to your LimeSDR will connect to it. The names of the operator (at least in a Android Device) only appears after connecting to it.
+
+That **openbsc.cfg** file will be used by **osmo-nitb** software. The next file is **osmo-bts.cfg**
+
+```
+!
+! OsmoBTS configuration example
+!!
+!
+log stderr
+  logging color 1
+  logging timestamp 0
+  logging level rsl notice
+  logging level oml notice
+  logging level rll notice
+  logging level rr notice
+  logging level loop debug
+  logging level meas debug
+  logging level pag error
+  logging level l1c error
+  logging level l1p error
+  logging level dsp error
+  logging level abis error
+
+!
+line vty
+ no login
+!
+phy 0
+ instance 0
+  osmotrx rx-gain 40
+  osmotrx tx-attenuation 50
+ osmotrx ip local 127.0.0.1
+ osmotrx ip remote 127.0.0.1
+ no osmotrx timing-advance-loop
+bts 0
+ oml remote-ip 127.0.0.1
+ ipa unit-id 1801 0
+ gsmtap-sapi pdtch
+ gsmtap-sapi ccch
+ band 900
+ trx 0
+  phy 0 instance 0
+```
+
+The only importante parameter here to take care is **band**. Make sure is the same as in *openbsc.cfg* file. The next one is *osmo-trx.cfg* which will be used by *osmo-trx-lms:*
+
+```
+log stderr
+ logging filter all 1
+ logging color 1
+ logging print category 1
+ logging timestamp 1
+ logging print file basename
+ logging level set-all info
+!
+line vty
+ no login
+!
+trx
+ bind-ip 127.0.0.1
+ remote-ip 127.0.0.1
+ base-port 5700
+ egprs disable
+ tx-sps 4
+ rx-sps 4
+ rt-prio 18
+ chan 0
+  tx-path BAND1
+  rx-path LNAW
+```
+
+There are not much to change here. If you’re using a multi-port LimeSDR (like LimeSDR USB or PCIe) you can change the parameter *tx-path* and *rx-path *to the desired paths.
+
+## Running the software stack
+
+There are a few programs to run to get the BTS working. You should run all of them from the folder you created the configuration files.
+
+The first one we should run is osmo-trx-lms . This one should be ran as root to enable high priority scheduling (specially needed if you’re running a small SBC like a Raspberry PI).
+
+```bash
+sudo osmo-trx-lms
+```
+
+![OSMO TRX LMS running](/assets/limebts/1_KbNtmYsmaCMVJinWnJdhFg.jpg)
+
+The second one is the osmo-nitb which is the base station controller. This one doesn’t need to be ran as root.
+
+```bash
+osmo-nitb
+```
+
+![Osmo NITB running](/assets/limebts/1_MmIJlBChAK1XF8TzxoX80g.jpg)
+
+And the last software is the osmo-bts-trx which handles the transceiver:
+
+```bash
+osmo-bts-trx
+```
+
+![Osmo BTS TRX running](/assets/limebts/1_2il3cVVy8yFsX5hNsESyDw.jpg)
+
+Now your base station should be running.
+
+## Testing the Base Station
+
+The best way to test is to have a custom simcard like this one:
+
+![Sysmocom Custom Simcard [http://shop.sysmocom.de/products/sysmousim-sjs1-4ff](http://shop.sysmocom.de/products/sysmousim-sjs1-4ff)](/assets/limebts/0_pKv_npHA_3DhtIQi.jpg)
+
+But since we set the BTS to *accept-all* mode, you can just go to your phone network settings and select the created network. That will work fine if you have an Android phone which allows you to select custom networks:
+
+![List of networks in an Android Phone. Here the 72470 network I just created](/assets/limebts/1_8_tklU4IBXyxERiyDkxl-w.jpg)
+
+Here is the network I just created with MCC 724 and MNC 70. In some simcards it is required that the MCC is the same as sim country (for example here it only shows if the network is at 724).
+
+After connecting to the network, the name should appear instead of the MCC+MNC code:
+
+![HUEBRNetwork showing in the list](/assets/limebts/1_CrDQk7YysiFXzgaOrxaTQA.jpg)
+
+## Listing Subscribers
+
+There is a simple python script to list the subscribers. What it does is to open the sqlite database and do a simple query and print.
+
+```python
+#!/usr/bin/env python
+import sqlite3
+
+HLR_DATABASE = "hlr.sqlite3"
+db = sqlite3.connect(HLR_DATABASE)
+c = db.cursor()
+c.execute("SELECT * FROM Subscriber")
+
+print "ID\t\tcreated\t\tIMSI\t\t\tTMSI\t\textension\n"
+while 1:
+    subscriber = c.fetchone()
+    if not subscriber:
+        break
+
+    print "{0:1}\t{1:2}\t{2:<15}\t\t{3:<10}\t{4}".format(
+            subscriber[0],
+            subscriber[1],
+            subscriber[3],
+            subscriber[7],
+            subscriber[5]
+            )
+
+db.close()
+```
+
+The IMSI field is unique to that phone / simcard combination. That’s the number you can use to track a specific user around the world. The extension is the assigned phone number for that specific phone.
+
+## Sending SMS
+
+There are two scripts I found in the internet to send SMS. They basically selects the IMSI from the sqlite database the Osmo stack creates and then connects through the telnet interface to issue the desired commands. One of them is *sms_broadcast.py*:
+
+```python
+#!/usr/bin/env python
+import telnetlib
+import sqlite3
+import sys
+
+imsi = 999999999999999
+HLR_DATABASE = "hlr.sqlite3"
+
+def check_extension(extension):
+    conn.write(b"show subscriber extension %s\n" % extension)
+    res = conn.read_until(b"OpenBSC> ")
+
+    if b"No subscriber found for extension" in res:
+        create_subscriber(extension)
+
+def create_subscriber(extension):
+    print("No user with excension %s found. Creating new..." % extension)
+    print("Extension: %s, IMSI: %d" % (extension, imsi))
+
+    conn.write(b"show subscriber imsi %d\n" % imsi)
+    res = conn.read_until(b"OpenBSC> ")
+
+    if b"No subscriber found for imsi" in res:
+        conn.write(b"subscriber create imsi %d\n" % imsi)
+        conn.read_until(b"OpenBSC> ")
+
+    conn.write(b"enable\n")
+    conn.read_until(b"OpenBSC# ")
+    conn.write(b"subscriber imsi %d extension %s\n" % (imsi, extension))
+    conn.read_until(b"OpenBSC# ")
+    conn.write(b"disable\n")
+    conn.read_until(b"OpenBSC> ")
+
+def get_users():
+    # returns user id list generator
+
+    db = sqlite3.connect(HLR_DATABASE)
+    c = db.cursor()
+    c.execute("SELECT * FROM Subscriber")
+
+    for subscriber in c.fetchall():
+        yield subscriber[0]
+
+def send_sms(id, extension, message):
+    conn.write(b"subscriber id %d sms sender extension %s send %s\n" % (id, extension, message))
+    res = conn.read_until(b"OpenBSC> ")
+    if b"%" in res:
+        print(res)
+        exit(1)
+
+if __name__ == "__main__":
+    try:
+        extension = sys.argv[1]
+        message = " ".join(sys.argv[2:])
+    except:
+        print("usage: ./sms_broadcast.py extension message")
+        print("This script sends a message from the specified extension (number) to all devices connected to this base station")
+        exit(1)
+
+    conn = telnetlib.Telnet("127.0.0.1", 4242)
+    conn.read_until(b"OpenBSC> ")
+
+    check_extension(extension)
+
+    for id in get_users():
+        send_sms(id, extension, message)
+```
+
+This one is pretty simple to use:
+
+```bash
+python sms_broadcast.py "source number" "message"
+```
+This will send an SMS to **all** connected devices as it was the *source number*.
+
+Another option is to target a single user:
+
+```python
+
+#!/usr/bin/env python
+import telnetlib
+import sys
+import random
+import time
+
+imsi = 999999999999999
+
+def check_extension(extension):
+    conn.write(b"show subscriber extension %s\n" % extension)
+    res = conn.read_until(b"OpenBSC> ")
+
+    if b"No subscriber found for extension" in res:
+        print("Phone with extension %s not found ;(" % extension)
+        exit(1)
+
+def check_spam_subscriber():
+    conn.write(b"show subscriber imsi %d\n" % imsi)
+    res = conn.read_until(b"OpenBSC> ")
+
+    if b"No subscriber found for imsi" in res:
+        conn.write(b"subscriber create imsi %d\n" % imsi)
+        print(conn.read_until(b"OpenBSC> "))
+
+def send(extension, spam_number, message):
+    print("Sending sms from %d..." % spam_number)
+
+    conn.write(b"enable\n")
+    conn.read_until(b"OpenBSC# ")
+    conn.write(b"subscriber imsi %d extension %d\n" % (imsi, spam_number))
+    conn.read_until(b"OpenBSC# ")
+    conn.write(b"disable\n")
+    conn.read_until(b"OpenBSC> ")
+
+    conn.write(b"subscriber extension %s sms sender extension %d send %s\n" % (extension, spam_number, message))
+    res = conn.read_until(b"OpenBSC> ")
+
+    if b"%" in res:
+        print(res)
+        exit(1)
+
+if __name__ == "__main__":
+    try:
+        extension = sys.argv[1]
+        repeats = int(sys.argv[2])
+        message = " ".join(sys.argv[3:])
+    except:
+        print("usage: ./sms_spam.py extension [num of repeats] message")
+        print("This script sends a message to specified number")
+        exit(1)
+
+    conn = telnetlib.Telnet("127.0.0.1", 4242)
+    conn.read_until(b"OpenBSC> ")
+
+    check_extension(extension)
+    check_spam_subscriber()
+
+    for _ in range(repeats):
+        spam_number = random.randint(1000,9999)
+        send(extension, spam_number, message)
+        time.sleep(2)
+```
+
+This one generates a random source number and sends the specified message **n** times.
+
+```bash
+python sms_spam.py "target number" "number of times" "message"
+```
+
+### References
+
+* [Creating your own GSM Network with LimeSDR](https://lucasteske.dev/2019/12/creating-your-own-gsm-network-with-limesdr/)
+* [OpenBSC: Configuration Modes](https://osmocom.org/projects/openbsc/wiki/OpenBSC#Configurations-Modes)
+* [osmobsc vty reference](https://ftp.osmocom.org/docs/latest/osmobsc-vty-reference.pdf)
+* [LimeSDR](https://limemicro.com/)
+* [Sysmocom Custom Simcard](http://shop.sysmocom.de/products/sysmousim-sjs1-4ff)