In 802.11 WLAN, there is data rate change of the connection as Dynamic rate scaling or Automatic Rate Selection is working. Is there any event triggered from the card so as to notify the OS (Linux Kernel event) about the same?
I know something about "iw events". Unfortunately it does give events like association, authentication etc but not of the data rate changes.
Please let me know if anyone aware of such functionality on any wireless card.
Thanks, Kedar
TX or RX rate?
It also depends on what kind of driver is used. If the rate control algorithm is implemented in the firmware then likely it's not possible. If the driver uses mac80211 then you can create a monitor interface and use e.g. tcpdump:
% sudo iw phy0 interface add mon0 type monitor
% sudo ifconfig mon0 up
% sudo tcpdump -ni mon0
Then you'll also get quite some information about the PHY for each packet.
Related
I am trying to integrate an RFID1356MIFARE, which uses NXP PN532, with an ESP32-EVB using their UART capabilities.
The NXP docs states that the PN532 is able to communicate on High Speed UART.
I am trying to use 38400 because that's the baud rate fixed by the reader that I'm using.
I've found a modified Adafruit PN532 library that added HSU support. This library states that HSU uses 115200 baud rate.
Now, I've modified PN532_HSU.cpp, where we can find:
void PN532_HSU::begin()
{
_serial->begin(115200);
}
into
void PN532_HSU::begin()
{
_serial->begin(38400, SERIAL_8N1, 36, 4);
}
Unfortunately, I haven't been able to establish communication between the reader and the ESP using this method.
I am able to get a readable output using normal Serial.read(), so UART communication works, but that's not how you read MIFARE cards.
I don't know what the problem is.
What do you think ?
[EDIT]
I went through the documentation and here is what i suggest: If you have a USB to serial device use it to directly connect reader module to computer else connect it directly using mini USB port in module. the follow following steps:
Put device in UART/ USB CDC mode depending on how you connected device to computer. Exact method to do this is provided in operation section of documentation
Use picoterm / screen or other serial terminal (if you are using Linux) or just use Arduino serial monitor with correct baud rate to connect device.(115200 for USB and 38400 for UART)
Type in commands listed in COMMAND SET FOR CDC AND UART MODE section in documentation to check if module is working or not.
Place some cards over reader to check what response does module sends when card is detected.
Use this information to develop your own library for reader.
It will not work with regular PN532 libraries. Instead you'll need to use regular Serial read and write to communicate.
[Original]
PN532 datasheet says host interface is selected by pulling up/down I0, I1 pins of device. For HSU both pins must be pulled down. This is implemented in hardware so you need to verify if the mode you want to use is set.
Looking into the link you posted for module, it says that it uses another micro-controller on board to extend communication capabilities, so maybe you need to use driver for that specific controller firmware? The link seems to have document explaining how to setup different communication system in Document section, please have a look there and check if it works.
Link: https://www.olimex.com/wiki/MOD-RFID1356MIFARE
First allow me to say that I don't have any experience developing drivers for OSX, nor drivers for Windows. So, there are a lot of things that I don't understand about how drivers work; I'm sure it'll be evident in my question.
I have a modem that is able to open and close TCP/UDP sockets using AT commands. I would like to create some kind of program (kernel extension? driver?) that implements a network driver, converting the network interface calls into AT command serial messages.
That's the basic jist of it. I'm essentially asking if anybody can point me in the right direction / give me a high level overview of how they would approach it and what Apple guides to focus on.
The XNU networking stack -- like most network stacks -- expects network devices to send and receive IP packets directly. It isn't tooled to work with network devices that handle part of the network stack (like TCP or UDP) internally -- it won't be possible to implement a network driver which uses this device.
You might have more luck exposing this device as a SOCKS proxy. You will need to write a userspace daemon which listens on a TCP port on localhost (on the computer) and relays traffic to the serial device; once that's done, you can set the computer to use that device as a SOCKS proxy in the Networking control panel.
(As an aside: most devices that implement this type of interface have a very low limit on the number of open sockets -- often fewer than 10. They're unlikely to be able to handle the network load generated by a desktop OS.)
I have connected a PiCAN2 board with raspberry pi running latest Jessie. When I try to send some CAN messages to my PC ( PC is connected via a USB to DB9 CAN interface to the PiCAN2 board) through this PiCAN2 using the can-utils, it runs into ERROR-PASSIVE state as soon as I bring the CAN interface up. But, when I enable loopback mode, I am able to send messages and receive them using two different terminal window on the raspberry pi itself. I enabled loopback mode using
sudo /sbin/ip link set can0 type can bitrate 500000 loopback on.
Can some one tell me more about the loopback mode? I want to make sure that my hardware setup for PiCAN2 is correct. Is it possible to confirm that my CAN board is configured correctly because I can send/receive messages using loopback mode?Or this doesn't necessarily mean that it is correct?
I also want to know why I get the ERROR PASSIVE mode - does it indicate that the PiCAN2 is not configured correctly OR does it mean that my USB to DB9 CAN interface has some problem? I am new to this area and any help would be nice. Thank you.
I need some info about advanced KVM network parameters. By advanced I mean the onces that are not accesible form GUI.
Something like:
network interface bandwidth
setting max transfer rate for emulated
network card
Are there any? I've had hard time googling for them
Emulated cards run with tap/macvtap interfaces from Linux. That's where you can set/query the parameters of the interface. For more gory details about tap interfaces & qemu you can read this post.
Above link given by dtatulea is really good.
I am writing my own program, which will be running on a 802.11 AP, to capture all the outgoing beacons on the AP. But I just noticed I cannot do it with the current libpcap: the program couldn't capture any outbound beacons. I've also tried Wireshark which gave the same result.
My questions are:
Can anyone shed some lights on the causes of what I saw?
Is there any user space method that I can capture the outbound beacons of a 802.11 AP on that specific AP (rather than capturing on other PCs)? It is better for me if I can do this without hacking into the wireless driver.
I am using Ubuntu 10.04 as the OS, Madwifi as the wireless driver.
Thanks, folks.
I would guess that the WiFi chip is generating the beacons autonomously
so they never pass the driver-chip interface where libpcap intercepts
packets. You'll probably need a second radio to be able to capture the
beacons from the air (when the primary radio is busy sending a beacon
the receiver is turned off so it can't hear what it is transmitting).
You can Capture those packets(Beacon ,Acknowledgement,etc) in wireshark
all you need to do is following :
go to capture menu
after selecting your interface go to option
select the per packet information option in link layer type of your interface
press start