I simply need to associate an extension number to an ip-address on an H.225 message.
I have already recording RTP payloads, converting, mixing, everything but today, my extensions need to be ip-fixed .
All i need is the ext. number.
C/C++ code is welcome.
Thanks a lot
The association between IPs an E.164 numbers in H.323 is done through the gatekeeper. Take a look at the GNU Gatekeeper.
Related
I need to do some NON-STANDARD signal processing operations with an RFID-reader, so I'd like to know if it is possible to extract antenna's individual analog (actually digital samples right after ADC) input signal samples with Motorola FX7500 (if you know how this works on FX7400 or FX9500, please do tell, could be helpful). Samples would be processed in a JAVA-based host computer program.
What I've already tried:
Investigating Motorola's own RFID3 API's possibilities, it doesn't go deep enough to actually get in touch with input analog signal samples.
Using LLRP to its full extent, it doesn't allow analog signal sample access either. RFsurvey-functionality would have been helpful to some extent, but FX7500 doesn't support it either.
Accessing RFID-reader's linux terminal, trying to find the driver function(s), that could listen the input sample stream. If current input sample(s) could be extracted from the input stream, I could (in theory) make a script, that would save a few of those sample values in a txt-file in the host computer during a tag inventory round. My linux skills are kinda bad, hence I ask this question.
The only realistic way to solution seems to be via linux terminal, so if you folks have any ideas about that (where to look and what to do), please advise!
Contents of reader:
rfidadm#FX7500abcdef:/$ ls -1
apps
bin
dev
etc
home
include
lib
linuxrc
media
mnt
platform
proc
readerconfig
run
sbin
sys
tmp
usr
var
I cannot completely rule that out, but it's highly unlikely you can get the raw signal digitized; the devices you're looking at aren't really software defined radio devices, typically.
"speaking" RFID physically is a bit different from "usual" wireless communication: The reader doesn't only observe the energy transmitted from the tag, but more importantly the fluctuations of energy extracted from the near field of the reader's antenna coil. Hence, you don't actually have a baseband of RF bandpass signal, but hardware-specific modulations of transmitted (and inversely, antenna-reflected) energy. Demodulation is hence usually done in specialized hardware.
However, do not fret: It's totally possible to build a software defined RFID reader. There have been several approaches to that, but personally, I trust these based on Ettus USRPs and/or GNU Radio best. Look through the results IEEExplore gives you, eg. this search.
Most probably this is not possible with the Motorola readers. What you can do, is use one of the RFID chipsets available on the market: either the AMS RFID IC's, or the Impinj RFID IC's. As far as I know, both IC's support retrieving the digital samples that are received. They also have a development kit to test-drive the IC's.
Using the BlueZ BlueTooth stack, How do I programatiacally enumerate devices that are already paired and not necessarily connected?
Update: The below wasn't as easy as I initially thought to be. adapter_get_devices is only the starting point. It will be helpful, if you could post a sample out of that.
If you don't have enough time, you can as well use the same bt-device tool from command line with appropriate command line params and get the output via pipe. Other choice is to use the ListDevices API in org.bluez.Adapter interface to get a list of paired devices and then I hope some thing in org.bluez.Devices interface will help you.
Update 2: In devices interface you can use, GetProperties method as in this answer
Does this gsoc code sample link help. It is in C now and hope it could be done over Python dbus as well. API is adapter_get_devices. I am yet to try this.
I was wondering if it is possible to modify the contents of a BLE beacon to include extra information. If you insert an extra bit at the end you could potentially broadcast a boolean in one direction. Theoretically, if you modified your device to read the extra bit of information this would work. Given existing protocols though it sounds like this would be a lot of work. Is there something out there like this already?
For info, I'm working on the mbed platform where you can modify your own bluetooth beacon payload.
Yes, you can do this with the new AltBeacon specification. There is a one byte manufacturer reserved field which you can use for whatever you want (tied to your manufacturer ID).
There are reference implementations of the specification available for Linux to show you how it works, and there is no reason you cannot implement it on the mbed platform.
I want to drop outgoing IP packets from my machine based on some criteria. I checked the capabilities provided by iptables but unfortunately it doesn't have what I am looking for.
So what I want is access to packets (at least those generate on my machine and going out). And based on some criteria the ability to drop them.
Should I be looking at modifying the iptables source code to add this functionality OR should I make a Linux kernel module to do this? or is there something else I should look into?
I want some general guidance but any specifics like a particular file in iptables where such functionality can be added will be very useful too!
You can use the NFQUEUE target of the netfilter. It sends packets to a userland program which can parse the payload and return a decision like DROP or ACCEPT.
You can find documentation and examples on the netfilter website.
This functionality is mentionned at the beginning of man iptables...
From what you're describing, it sounds like what you're trying to do could probably be implemented as a new iptables match. You'd have to tell us what conditions you're trying to drop packets based on before we could advise you in more detail, though.
I'm pretty sure iptables could be used to drop packets based on the condition. If the condition is complicated you might need to write your own netfilter plugin (http://netfilter.org/) to augment what can be done with iptables.
I'm trying to anonymize packets from a pcap file that I have. I need to discard all the packets payloads/content (leaving only header information) and was wondering if there would be a tool that I could use for this (on Linux)? I have thought about using tcpdump with specifying the snaplen but with the header length changing, I don't think that would work.
If there isn't a tool that could accomplish this, a point in the direction of what library for coding would be best(easiest) would work as well. I'd rather not take that route since I have virtually no experience in network programming.
Any help is much appreciated.
You don't need any network programming experience to anonymize the packets. The format of the output file is well documented in the pcap-savefile(5) manpage. You will need to lookup the layouts of the various protocols you'll be handling in order to identify what fields need to be anonymized. You should also look at the link layer header types documentation at tcpdump.org to help you get started.
EDIT: Also look at libpcap itself... according to the pcap-savefile manpage:
NOTE: applications and libraries
should, if possible, use libpcap to
read savefiles, rather than having their own code to read
savefiles.
If, in the future, a new file format is supported by libpcap,
applica-
tions and libraries using libpcap to read savefiles will be
able to
read the new format of savefiles, but applications and
libraries using
their own code to read savefiles will have to be changed to
support the
new file format.