If I send a packet containing address, port and other stuff, would there be any alignment problem on the other side? (using socks 5 protocol)
You don't mention which language you're programming in. If you're using C or C++, there are functions like htons, htonl, ntohs, ntohl and more to standardize network data elements into a transportable format. This guide (among many others) will tell you how to write network portable code so differences in endianness will not bite you in the #ss.
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I'm trying to write a simple DPI (Deep Packet Inspection) tool. In my current phase, I need to develop a H.323 protocol detector. To aim this goal I need a H.225 / H.245 packet generator. I seems that almost all tool use SIP and RTP & RTCP protocol. Does anybody have any idea which tool use H323 protocols in VOIP?
There is number of h323 libraries, some of them are openh323 and openoh323/openooh323.
But ALL libraries have issues and alot of bugs. Main issue - protocol is VERY complex if compare with sip or other modern protocols and ALL vendors do "vendor-specific" addons/changes in protocol way they think "better for client".
As result it is hard to work with any tools. Easy way detect is just get signatures like 'h323', 'rtp' etc.
Is there any other way than idl2wrs&compilation of wireshark to properly interpret the data in CORBA GIOP protocol?
I was actually thinking about Lua but cannot find anything like register_giop_user_module
GIOP is not a self-describing protocol when encoded for transmission. You'll always need the IDL to interpret the payload bytes on the wire. The idl2wrs tool works by coupling the IDL with the bytes found through snooping, so unless you have another tool available that works on a similar principle, you'll be out of luck.
I've been searching for some information regarding microcontroller programming but the info I find is either way over my head or doesn't appear to exist. I'm looking for something easier to digest! I'm relatively new to programming and come from an SQL DBA background and decided that it would be quicker for me to learn some programming fundamentals and then teach myself Delphi than it would to get some changes implemented through my company's insane design change note system!
After a couple of years of Delphi programming I can cope with writing database applications without too much bother and I want to be able to move on a level.
We use PIC microcontrollers on our PCBs; mainly the PIC18F family. The software on the PICS is written in C but there are parameters values that are written to by a Delphi application that interface with the PIC using an ActiveX control.
Basically, SQL Database holds parameter info, Delphi client app retrieves those values, passes them to the ActiveX controll which does all the low level stuff on the PIC. For example the internal EEPROM will have a map and within any particular address a value will be stored to switch something on or off or hold an integer value etc.
I've gotten hold of an MPLAB kit which has an ICD2 device that can read and write values to the internal EEPROM and I understand how to change these hexadecimal values using MPLAB software.
My hope isn't to learn embedded microcontroller programming; rather that I can write a Delphi app that will do something similar to MPLAB software. E.g read and write values to certain memory addresses within the EEPROM.
I'd be very gratefull if anyone can point me in the right direction of any libraries or components that may already exist for bridging this gap between simple Delphi form application and writing low level PIC EEPROM. I doubt such any easy interface exists but I thought I'd ask. To summarise I want to be able to have a simple form app, with some edit boxes that the user types in or selects from dropdown boxes, parameter values, to click on a button and to assign those parameter values to specific EEPROM memory addresses. Thank you for reading and any comments would be gratefully received.
Regards
KD
I'm a big fan of MikroElectronika and have used their Pascal tools for pic16 series MCU with great success (touch screen interfaces, ZigBee, ...).
http://www.mikroe.com/
Updated 2015 Answer:
Why not a Raspberry Pi with FreePascal and Lazarus? The boards cost from $5 to $25 US, as of this date, and the development tools are free.
Original 2012 Answer:
If you like to use Pascal, you might find Free Pascal useful on small embedded systems, but the minimum I believe you will find it can compile on is a Linux-based ARM embedded system. The fact that you use pascal on both sides is very unlikely to help you accomplish anything major.
If you want to go all the way down the the smallest PIC microcontrollers, you'll find that it's almost always a variant of C that you'll be using. Frankly, at that level, the differences aren't that much. If you can write Pascal, you can learn enough C in a day, to use with microcontrollers.
Don't be scared to use the native language that most microcontrollers support. My personal favorites are the Rabbit microcontrollers, formerly from Z-World, now from digi -- I think I paid about $100 US for the first board and development toolkit.
Interfacing such an application with delphi is pretty easy, usually these days, I would interface using TCP/IP over either wired Ethernet, or wireless (Wifi). But if you really want to you could use RS-232 or RS-485 serial links. (RS-485 has the advantage that you can wire it up to 5 miles long.) If I was using a serial link, I'd probably implement something like Modbus on both sides, if I just wanted to send some numeric data back and forth, and if I was doing something text-oriented, I think I'd write a mini HTTP web server on the embedded controller, and most boards these days come with enough HTTP server demos to make that drop-dead easy.
Delphi outputs Win32 and Win64 native applications you can write software that can interact with certain devices if the PCB has serial comunication or I2C you can write software that in Delphi that it will interact with the physical device.
But if you want to programm the devices yourself , write software that will run on this devices you can't do it in Delphi. I suggest you buy an Arduino it's an excellent envoirment for beginners in microcontroller programming.
If you have the source code of your pic microcontroller then you can implement the code in C to read from Serial, USB or some other interface available in your hardware and write it to the eeprom. This way its easy to write the app in any high level language like delphi, c++, etc.
Or you can write your PIC application using the mikropascal compiler from mikroeletronika that its very good and I've been using for a long time, but as you can see you will have to implement some mecanism to read from the interface and write to your eeprom as I've mentioned before.
This compiler comes with a lote of librarys to work with many devices. You should take a look on it, its not free but the price is low and in their site you can find samples and sample boards to test it.
One option, if you want a simple interface to write to the PIC EEPROM, is to use the ICD command line utility. Unfortunately it is not available for the ICD2, but the PICkit 2 and 3 (which are cheap), ICD3, and RealICE have command line utilities that give you the ability to write to the EEPROM (google pk2cmd). In Delphi, you could just wrap a very simple set of command line calls to pk2cmd.
The protocol is very simple and is developed on top of TCP. I need to analyze a big libpcap dump file to calculate the average value and standard deviation of the conversation time and of the number of packets per conversation.
Using Wireshark it's simple to analyze the TCP conversations between the endpoints, but the summary includes all of the TCP packets (lots of SYNs, ACKs and FINs), and this messes up the data.
Is there another tool to do this kind of analysis? Is there a way to EASILY extend Wireshark's functionality?
You can check out the Argos custom protocol analyzer.
It is a commercial tool and it has a powerful and easy to use XML protocol definition language.
Additionally it can monitor Ethernet and IP traffic as Wireshark does and open Libcap files
Not sure I understand exactly what you need, but if you're looking to analyze only the packets with application data in them you can ask Wireshark to display only those packets with the PSH ("push to application") flag set.
What exactly this protocol contains? Is there any specific header for its own usage? Wireshark provides many complex filtering options that you can explore.
If you want to do it using program, you can try PCAP or PF_SOCK. You may need to write your own filtering criteria then.
Is there another tool to do this kind of analysis? Is there a way to
EASILY extend Wireshark's functionality?
You can try Scapy ( http://www.secdev.org/projects/scapy/ ), with Scapy it is very easy to add new protocols: http://www.secdev.org/projects/scapy/doc/build_dissect.html .
Scapy is not as Wireshark, but I think it will solve your problem.
I've been looking for a good general purpose binary network protocol definition framework to provide a way to write real-time game servers and clients (think World Of Warcraft or Quake III) in multiple languages (e.g. Java backend server and iPhone front-end client written in Objective-C and Cocoa).
I want to support Java Flash clients, iPhone clients and C# clients on windows (and XNA clients on XBOX).
I'm looking for a way to efficiently send/receive messages over a TCP/IP or UDP socket stream connection. I'm not looking for something that can be sent over an HTTP Web Service, like JSON or XML marshalled Objects. Although Hessian's binary web service protocol is a very interesting solution
I want a network protocol format and client/server basic implementation that will allow a client to connect to a server and send any message in the defined protocol and receive any message in the protocol without having to bind to some kind of RPC endpoint. I want a generic stream of any message in my protocol incoming and outgoing. This is so that I can support things like the server sending all clients the positions of various entities in the game every 100 milliseconds.
The network protocol frameworks I've found are as follows:
Google's Protocol Buffer - but it lacks support for things like sending/receiving arbitrary messages from your given protocol.
Apache Thrift - an interesting option but it is geared mainly towards RPC instead of generic game client/server socket type connections where the client or server can send messages at any time and not just in response to a client RPC request.
Raknet Multiplayer - Raknet provides full multiplayer network library (it's free for indie development with revenue under $250k)
UPDATE : OculusVR Acquired RakNet and its Free/OpenSource now. U can find it on Github
Hessian Binary Web Service Protocol - is a HTTP web service binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.
Raknet provides a good game/simulation oriented multiplayer library.
Apache Thrift and Google's protocol buffers seem to be the simplest approaches to using in a game network protocol client/server architecture.
Hessian seems like a great fit if you want to create a web based game server with a Java or flash client using some type of server push technology like COMET. Hessian might provide a really interesting way to support real-time games on the web and even be able to host them on VM web solutions like Google's App engine or Amazon's EC2.
There's some discussion about using various protocol definition frameworks for games and other uses:
Comparison of Various Serialization Frameworks
Thrift vs Protocol Buffers - Thrift is declared the better framework because it has a fully supported RPC client/server implementation
Using Protocol Buffers for client server Game API determining what type of message to decode
Bi-Directional RPC using thrift
DIS
If you do go the route of writing your own protocol, you may want to read the answer I posted here.
In summary it discusses what you should think about when writing a protocol, and list a few tricks for versioning and maintaining backwards and forward compatibility.
If you are really concerned about multiple platforms and language, be sure to take into account endian issues. A binary protocol designed for this use must use network-byte-order, so it needs custom per-data-type serialization functions; you cannot just blindly push C structs into network buffers.
A common solution for this problem at game companies is to have protocol description language or specification in a simple format like XML or python or lua, and then have code generation for each target language that generated packet classes with both data structure and serialization. This specification could use a type system that starts with basic types, then extends to include game-specific types with semantic information, enumerations or more complex structures. For example a data file could look like:
Attack = {
source = 'objectId',
target = 'objectId',
weapon = 'weapon::WEAP_MAIN',
seed = 'int'
}
This could generate code like:
#define PT_ATTACK 10002
class PacketAttack : public Packet {
public:
PacketAttack () : m_packetType(PacketAttack::s_packetType) {}
ObjectId m_source;
ObjectId m_target;
WeaponType m_weapon;
int m_seed;
bool Write(Stream* outStream) {
Packet::Write(outStream);
outStream << m_source;
outStream << m_target;
outStream << m_weapon
outStream << m_seed;
}
bool Read(Stream* inStream);
static const int s_packetType;
};
This does require some more infrastructure.. streams, packet base classes, safe serialization functions..
I want to echo Bill K's suggestion. It's not hard to roll your own protocol.
For the iPhone side, have a look at AsyncSocket which support for delimiter based TCP packets built in, and it's not hard to build a solution which uses packet headers.
If you quickly want to have a testserver to play against AsyncSocket on the iPhone, you can look at Naga (for the java server part) which has ready made stuff both for delimiter based packets and packets with headers. Naga was partially written with networked games in mind.
I disagree with "roll your with simple delimited strings approach": question is, what exactly would be the benefit? Getting to write and maintain more code?
The only reasons I could see would be lack of tool support (writing for some odd platform), or specific (very) hard performance or message size constraints.
Or, sometimes, really wanting to write a format -- that's ok, but it must be an explicit reason.
Depending on exact needs I would suggest considering JSON, since it can read and write arbitrary messages; has good object binders for Java (just like xml), is easier to read than binary formats, and is all around "good enough" for many use cases.
If message size is very important, Protobuf can work well -- while its size is not always as small as gzipped alternatives (gzip+xml, gzip+json compress very well), it's usually close.
ASN.1 fits the definition of "good general purpose binary network protocol definition framework". It's also standardized by ITU-T, so there's a lot of existing tools and libraries for various languages.
The DER encoding is suitable for efficient network communications, the XER encoding for human-readable (and writable) permanent storage.
Because you want to use different languages and also because you want something clean/small, I suggest the protocol buffers of google. You need a pre-compile part for the RPC but I really think that's the best option when you begin to mix different languages.. Here's the link: http://code.google.com/apis/protocolbuffers/docs/overview.html
Why not implement UDP directly? Your question mostly mentions what you don't want.. What further form of abstration do you want on top of UDP?
Download the Quake III sourcecode and see how they frame game updates over UDP?
The IP protocol has been designed to support multiple devices/OSes in a uniform way, isn't this what you ask for?
What protocol has implementations across a huge range of systems, hmm, IP perhaps?