I am trying to detect intrusions on a CAN bus configuration. To do this I want to try protocol conversion from CAN to IP (UDP) in order to use snort. I really don't know where to begin as I have not seen anything on protocol translation for a CAN bus at all. Is it even possible? Has anyone tried it?
I basically used a raspberry pi and several Arduinos to take temperature readings (from thermostats) and control hot/cold fans in order to regulate temperature. I know this is not a lot to go on, but as I said, I am just in the beginning phase of planning this protocol translation.
You can use cannelloni on your RPi. There are also stand-alone CAN-to-TCP/UDP converters like for example this one.
Related
I'm sorry if my question is too easy or obvious. I'm Comp. Science Student (it's my 6.th term).
I'm trying to combine the knowledges that I'm learning from 'Computer Networks and Security', 'Computer Organization' and 'Operating Systems' lectures in this term.
So, I cannot figure out that;
Does a computer or a phone has physical components for each 65535 ports/sockets?
Or
The machine has just one physical component. So that means port numbers are logical representations that can be shown as text-fields (like header entities or json attributes) of a request or something, to say to computer how to handle the request?
I used ports for connections of back-end and android and front-end. I know that a socket is a physical component, I worked 4 months as phone-repairer, I know these. But this makes me confused.
Thanks in advance..
Think of it this way: "the network interface is the phone system, IP-addresses are phone numbers, and socket/port numbers are like telephone extensions. (The network interface is the only physical device.)
Network traffic is carried by so-called "packets" which have various fields which tell the network how they should be routed. The IP-address will get the packet to the proper destination, then the port/socket-number will specify exactly what software process at that destination should actually handle this packet.
I need to change an i2c address of an amphenol nova sensor NPA201 (pressure) using an stm32F407-discovery board.
An application note provided by manufacturer raises some questions.
According to the table, the one must set cpu's i2c module to master-receiver mode, and immediately send a byte to sensor. Is it even possible to do so?
May be i need to read reference manual one more time, buy as far as i know such situation is not described there.
Has anybody done the changing address procedure before?
table
Information for changing the address of the sensor can be found here Please note you can only change it three times. The default i2c address is 0x27.
I'm looking to design a bus functional model for SPI and UART bus. First, I want to understand if my perception of a bus functional model is correct.
It is supposed to simulate bus transactions, without worrying about the underlying implementation specifics.
For instance,
If I were to build a BFM for an SPI bus, the design should be able to simulate transactions on the SPI acting as a master based on some protocol for example reading instructions from a file and then showing them on a simulator accordingly,
For example a generic data transfer instruction, like send_write(0x0c, 0x0f), that sends data byte 0c to the slave address 0f, should drive the Chip Select line low and send the data bits accordingly on the clock edge based on the SPI mode, is my understanding of BFM correct in this case?
Now what I don't understand this is, how is it helpful?
Where in between the DUT and the TestBench does a BFM sit, and how does it help a system designer.
I also want to know if there are any reference BFMs that have been built and tested that are available to study,
I'd appreciate if someone could help me with an example, preferably in System Verilog.
So had to research a lot on this so I thought I would answer, but here's an idea of what it is,
Think of a Bus Functional Model(BFM) that simulates transactions of a bus, like READ and WRITE, reducing the overhead of a testbench of taking care of the timing analysis for the same. There are a lot more interpretations of a BFM, BFMs typically reduce the job of a testbench by making it more data focused.
Okay that was a high-level answer, let's dig a little deeper,
Think of BFM as a block that sits within the testbench block as a whole, when the test bench needs to perform a task, for instance, wants to write at a particular address, it asks the BFM to write at that address, the BFM, which is a black box to the test-bench does the transaction whilst taking care of the timing. It can be driven by a file that could be loaded by the test-bench or it could be a bunch of tasks that the test-bench uses to do the transactions.
The Design Under Test's(DUTs) response to the BFM transacts is of interest to the tester for the design. One may argue that the BFM may change based on DUT, which is what distinguishes a better BFM per say.
If the BFM could have a configuration vector that could be loaded to initialize and behave according to the DUT specifications, then it becomes portable to helping test other designs.
Further the BFM, may be defined as abstract virtual functions(in SV), that could have further concrete implementations based on the DUT.
virtual class apb_bfm;
pure virtual task writeData(int unsigned addr, int unsigned data);
pure virtual task readData (int unsigned addr, output int unsigned data);
pure virtual task initializeSignals();
endclass
The above BFM abstraction is for the APB Master, that does the tasks mentioned, the low level details of each of these must be encapsulated by interfaces and clocking blocks in order to have sanity of the clocks as well as abstract interface types. I have referenced a book in the section, which describes beautifully how to architect test benches and design Transaction Level Models(TLMs). Reading this will give you a good understanding of how to design one.
Also this paper on abstract BFMs gives a good idea on how BFMs should be modeled for a good design. The APB example is derived off that.
The following image on how a BFM could be placed in the test framework was what I could gather from Bergeron's book.
Hopefully that gives a basic understanding of what BFMs are. Of course writing one and getting it to work is difficult but this basic knowledge would allow you to have a high level picture of it.
Book Reference:
Bergeron, J. (n.d.). Writing TestBenches in System Verilog. Springer.
A BFM is a VIP with dual roles. It can act as a Driver or a Monitor/Receiver. In a Driver role, it packs the transactions and makes it drive on a signal level using the interface handle, else the DUT is unable to accept the transactions (it only has signal interface). As a receiver, it unpacks the signal bits coming through the interface handle, to transactions and sends it to Scoreboard/Checker. It can also act as a Protocol Checker in some cases.
You can get a good example of BFM usage here
http://www.testbench.in/SL_00_INDEX.html
I am reading linux device driver book of rubini,corbet and hartmen.I have doubt regarding dynamic allocation of major and minor device numbers.They say
The disadvantage of dynamic assignment is that you can’t create the device nodes in
advance, because the major number assigned to your module will vary.For normal
use of the driver, this is hardly a problem, because once the number has been
assigned, you can read it from /proc/devices.
1)What does it mean by advance here?
2)Why major and minor numbers must be read from /proc/devices when function alloc_chrdev_region provides major and minor numbers in the argument sent to it.can that argument sent, not be used directly?
Thanks in advance
1) Dynamic assignment would mean that you cannot create device nodes before the driver is loaded, for example having them as a static part of the filesystem when the system boots. Instead you could only create them once you discover what their major/minor numbers are this time.
2) The driver may know what it's major and minor numbers are, but the device nodes should be created by something in userspace. They are suggesting that if this information cannot be given in advance in parallel to both the kernel driver and userspace, then userspace will have to discover it at runtime from something such as /proc/devices.
When we assign a major number dynamically to a device driver, we are not aware with the Major Number till the alloc_chrdev_region function finishes execution or let's say that you don't get to know the Major Number before you insert the module into the kernel (and for this we use insmod). And so you cannot create a node for your driver (for which we use mknod) unless you load a device driver, this is referred to as advanced by the author.
We read /proc/devices for Major and Minor Numbers of one device driver when a different device/program needs them.
Consider the following Ladder Program that checks if a connection is enabled (A202.00) then send a message from the PLC to the PC.
The documentation (Omron CX-Programmer) has a severe lack of explanation of the program convention. What I do not understand is:
To send a message from a node to a node. I should need to specify the receiver ID. It seems the function block does not have an option where I can insert an IP address. Am I supposed to MOV an IP address to a DM address (D300) then use it? If that's the case how (IP address has dots in between 4 bytes..)?
Can someone please explain what is S (First source word), D (First destination word) and C (First control word). Aren't they just memory address? E.g. sending content of a memory adress to another memory address?
[EDIT]
What am I trying to do?
I am trying to interface a measuring gauge (controlled through Ethernet by PC/C# application) to a robotic system (no RS232 or serial, no TCP/IP, only has the simplest I/O points) with an Omron PLC. When gauge completes a measurement, the C# app sends a command to the Omron PLC which, according to the command received, switch ON or OFF an output which triggers a voltage flow to the robot's I/O port.
Should I use FINS? What functions/protocol from the PLC I need to know to do this? I do not know so I am testing every function from the documentation. So far, zero progress.
1) All addressing information is encapsulated in the five control words (C -> C+4). C- "First Control Word" is the pointer to the first word in this table of five words you must have stored somewhere in your PLC to set up the communication.
2) First source word points to the first word in your PLC you wish to send. First destination word points to the first address in the PLC/device you wish to send to. In the example , the first control word specifies that 10 words should be sent. You point to the first one and it will send that one plus the next nine addresses as well.
To do this you have to use FINS communication - the PC stores a memory structure similar to the PLCs (CIO, DM, etc) called Event Memory and these are the addresses in the PC you are pointing to. The PC gets a FINS node number and address just like a PLC would - no IP addresses are involved. (see : FINS Manual) FINS is old, however, and has been superceded by things like Sysmac Gateway.
There are much better ways of communicating between PLC/PC, however, depending on what you are trying to do. Are you trying to write an HMI? If so, what language are you using?
Edit :
If you're using C#, I highly recommend you look into Sysmac Gateway and CX-Compolet. This is probably the most flexible, simple, and extensible way to get .NET working with Omron PLCs. If it is at all possible, however, a better way might even be to have the measurement unit communicate directly with the PLC via hardware I/O (relays, DIO, etc).
CX-Compolet, Sysmac Gateway link:
http://www.ia.omron.com/product/family/63/index_l_u.html