I know that when a PC is OFF, some components still working ,like the motherboard, the NIC (network card), and others. I thought that like the 'magic packet' send to the NIC on the Wake-on-Lan do, there is a form of sending another signal to this one.
How can I get the SMBIOS table, through the Network Card of a remote and power-off PC?
If someone knows of some code example, or manual which can read to learn, it would be very helpful.
How can I get the SMBIOS table, through the Network Card of a remote and power-off PC?
You can't. WoL is a function of the NIC. When it receives a magic packet it triggers a PMI event, waking up the mainboard - that's it. You can't magically talk through the NIC to the powered down system.
There are two solutions, depending on your actual goal:
Many servers, some workstations and PCs feature lights-out management through a baseboard management controller - features differ, you'll need to select the appropriate product.
Wake the machine, run whatever queries you need and shut it down again. This is a standard procedure for client management.
Related
I have a costume board with Xilinx Zynq UltraScale+ RFSoC.
I'm using 3 PS_GTR transceivers as sgmii.
2 of them are connected to external Marvell phy and the third connects directly (fixed link - without phy).
In the manufacturing stage i would like to make sure that the direct sgmii interface is assembled correctly - so I made an external loopback between tx and rx sgmii signals.
Now, Is it possible to transmit something through this external loopback and compare with the received data?
Is it possible to ping with yourself? (simple ping command not working: "ping -I eth2 ")
perhaps there is a 'patch' under the 'macb' kernel driver that someone can guide me through?
Thank you all,
Tzipi Kluska
Yes it is possible to ping yourself. Note that linux does or at least used to bypass the hardware when talking to itself and would do the loopback in the IP stack. I recently saw someone within a terminal (window, command line) isolate one network interface, then another another network interface and then it was trivial to use stock tools like ping and iperf to test the link.
Before doing that though, the serdes on your part should have PRBS capabilities (for a reason), some may have internal scope like features that allow you to extract an eye or at least numbers that indicate the quality of the eye. The marvell phy should also have this capability and you can both use a loopback to talk to yourself use various prbs lengths to check the quality of the link (less than one error in so many 10 to the 14th bits or whatever your desired quality is), and then when connected to the marvell repeat that.
Before doing all of this the software is often the hard part and you need to insure you have it working first, so you may wish to do loopbacks inside the fpga that do not have analog issues and get the software worked out, then in the serdes on the edge of the fpga they may have loopbacks in both directions, the marvell as well may have loopbacks in both directions so you can for example go direct fpga to marvell one is the tx and one the rx and vice versa, or you might enable a lan side shallow loopback on the marvell and talk to yourself.
Also depending on these speeds, hand made loopbacks might be noisy so sometimes a pcb based loopback (which also has to be designed) may wish to be deployed.
Can you ping yourself, absolutely. You can use other low level network interfaces like sockets, to make raw packets and talk to yourself through these interfaces as well. Ping, doing a ping flood, iperf, netperf, etc are all fine ways to exercise or get a warm fuzzy about the interface during both development and manufacture test.
Being an fpga you can of course have a test design that you load into the fpga that pushes the external interfaces and reports the bit error rate.
Is there any way to query the system's date/time via USB without installing anything on the host computer (maybe just drivers)?
Background of the original problem
To avoid the XY problem, let me explain a bit what I'm trying to do.
To be able to calculate a TOTP token for 2FA (e.g. like Google Authenticator app does) you need a real-time clock to get the date and time.
There's this USB device called SC4-HSM that I would like to use to calculate the tokens, however it doesn't have a clock and according to the designer, adding one would be too expensive (needs a battery, etc).
Possible solution to the original problem
This device is going to be used with a computer which already has an RTC of course. Thus I had the idea of querying the system for a date/time which would solve the issue.
(Note: I know that a USB device can be connected to all sorts of hosts and not all hosts will have an RTC, but since this only needs to work with a computer, I thought this shouldn't be an issue)
My first thought was that there might be some USB device class that had date/time needs, so I could register the device as that type and then I would be able to query the values.
After going through the device class codes list (Internet Archive) nothing jumped at me as needing date/time. The closest ones I could think of were:
Content Security (PDF)
Personal Healthcare
Smart Card Class (PDF)
I skimmed the device class documents in the USB Implementers Forum but there's nothing in there even remotely related to date or time.
Current problem
Since the USB specs seemed like a dead-end I thought that maybe there was a way to write a very simple USB driver that can be auto-loaded when the device is plugged in to a computer and then we can use the driver to return the date/time when the device asks for it (unless I'm misunderstanding something).
I am now looking through USB development docs like Michael Opdenacker's Linux USB drivers course, I tried the Linux USB Project which seems dead. Skimmed through Driver Development for Windows NT just to get an idea, however I am still not able to figure out if this is possible or not, and how hard it would be.
I'm a complete beginner at this and maybe this is something out of my skill level, but I would like to figure out if will I need weird hacks and workarounds or is there a much more straightforward way to do this?
There seems to be little information about it or I'm just searching the wrong places.
Any ideas/or pointers on either solving the original problem or the current one?
system time is not necessarily the general time i.e. the 'atomic' time you get from a NTP server
the most obvious solution is to use autorun, this is also possible on linux but normally autorun is blocked so the user explicitely has to activate it
https://askubuntu.com/questions/642511/how-to-autorun-files-and-scripts-in-ubuntu-when-inserting-a-usb-stick-like-autor
the linux command to get the time is date or hwclock or if the computer is connected to the net it may be possible to contact a NTP server (if the firewall does not block this)
then your autorun program has to send the data to the SC4-HSM. i do not know what USB classes the SC4-HSM implements if it implements CDC ACM (virtual COM port) this is easy:
Unable to sync computer time to Arduino via USB
(something like echo "T$(($(date +%s)+60*60*$TZ_adjust))" >/dev/tty.usbmodemfa131)
maybe it is possible to access system time over the USB drivers, i do not know this right now
TL;DR available at the bottom
I've been trying to figure out a way to get two laptops (both running Ubuntu) to be able to pass basic messages back and forth without the need for them to be connected via a wireless network,either by an AP or ad-hoc. I want to reiterate here that ad-hoc networking is not what I'm looking for, I've seen many similar questions here with that as the answer.
I guess what I'm asking is: how do I achieve this? All I really need is for one computer to be able to send a packet, and then for another to pick it up via a packet sniffer of some kind.
Currently: I have both laptops in monitor mode (via a mon0 interface created from aircrack-ng's airmon-ng)so that they can sniff nearby traffic (with Wireshark, tcpdump,tcpcump.org's sample libpcap code, and opening a raw socket and just printing out all the packets. I tried each just because I thought one could be doing something differently/leaving something out). I also have a very basic program that consists of opening a raw socket to send crafted ethernet frames out to the air, but I can't get my two machines to see the other's packets. The sniffer running on each machine can only see the packets going out of that machine (in addition to nearby beacons/control traffic from wifi in the area).
Some things to note that might be important are:
-the packets I'm sending out appear in Wireshark (only on the sending machine) as malformed 802.11 packets (probably because I'm just filling them with junk data for now). I was under the impression that my other laptop would also see them as malformed packets, but it gets nothing
-the sockets I'm using are from a call to socket(PF_PACKET,SOCK_RAW,ETH_P_ALL). Raw sockets are something I just recently was aware of, so I could be misunderstanding how they work, but my impression is that I can craft a layer 2 packet by hand and ship out straight out to the wire/air.
If you're curious as to why I want to do something like this, it's part curiosity, part research for a project I'm working on. I want to streamline / automate the process of setting up an ad-hoc network, and what I'm trying to do here is for the laptops to do a small exchange to figure out the specifics of the adhoc network they are about to create and then make/join that network automatically, instead of either one person explicitly setting up the network OR having both people pre-decide the name, etc of the network and have both computers constantly trying to connect to that specific one.
I'm more interested if I'm going about this process in the right way rather than if my code works or not, if someone thinks me posting my (very basic, taken from another post on Stack Overflow) raw socket code will help, I can.
Edit: I am more than happy to post a complete set of code with instructions if I can get this working. I couldn't find much helpful info on this topic on the internet, and I'd love to put it up for future people trying to do the same thing.
TL;DR I want to send out a packet from one laptop and pick it up on another via a packent sniffer of some sort. No wifi network or ad-hoc network involved. Something akin to spoofing an AP's beacon frame (or similar) for the purpose of sending small amounts of data.
Edit 2:After some thought, perhaps what I'm looking for is some kind of raw 802.11 use? Having direct control of the wifi radio? Is such a thing possible?
I found out I was able to send packets out through my monitor mode interface as long as I had correct 802.11 with radiotap headers. I think the problem I was originally experiencing (not being able to sniff the packets) was because they were malformed and thus not actually getting sent out.
I was able to accomplish this by adapting the example code found here, courtesy of someone named Evan Jones, except I did not need to use an Atheros based card or Madwifi drivers, everything worked fine with the mon0 interface created with aircrack-ng.
I am certain that Apple Mac do this. Apple call it 'bonjour'. There may well be a proper IETF spec for it. This is an Article on Bonjour this is Wikipedia on an open component of bonjour which might help get you moving.
I would like to send a message, or something can be an advise from a pc to an another pc (only one, or at the most 2), the latter is powered off.
The pc which should send the message is a windows server 2003 os, instead the pc which should receive the message is a windows xp os.
The two machines are in the same domain and they work together through an ingres database.
The message will be sent at night, because there is an ingres database back up procedure that runs at night when my pc will be powered off, but when in the morning i will be at work I would like to read this message as a net send message, or something like
Unfortunately the net send command is disabled in our network, so I can't use it, but i'm looking a way for sending this message.
Have you any suggestion? thank you
Use age-old simple file based messaging.
Store a message in a specific file in the server and write a simple application which runs on startup on your machine to read it and display it.
And this is apart from rerun's great suggestion :)
There is breaking new technology available called email.
Is the machine powered off or in standby?
If if is in standby, then I will defer to someone who may have a better idea of how to get wake the machine to wake up programatically(sp?).
If it is powered off then read on...
If you have access to the machines bios settings, then I would suggest scheduling a power on event in the range of the time before the backup normally completes.
Then it is a matter of receiving the message and optionally shutting back down afterward?
If you are unable to change the bios settings, then does the machine "power on after power loss?" If so, get a programmable timer from the nearest retail store and power off before leaving at night and have the timer set to power on before the time the backup could reasonably be completed.
This is not really a software solution per se, but your problem does seem to be mostly hardware related (with the power off requirement and all...)
I would like to create a wireless network from a laptop. If laptops come within range, I would like it to send them a welcome message and send them a goodbye message when they leave the wifi range. Is it possible to do this in C?
Please help me out with this.
It is possible, but it is a very complex task and I don't think that programming language choice is the first thing to look into.
As a start, you can read up on Wikipedia on Wireless ad-hoc networks.
How should your messages be received and displayed on the remote side? If you want to use some existing protocol over TCP/IP, or create your own (deploying custom applications on the remote machines), you will need to mess with networks and this is not always possible as one machine can be a part of only one network. So the machines need to be not connected to anything and somehow allow you to connect to them, it involves changing network settings on all that machines (for example, setting them to join the ad-hoc network with predefined name).
If all machines automatically join the existing network, this question has nothing to do with wireless (physical layer) but with Avahi, Netbios or whatever other services allowing you to get notifications and/or enumerate devices in the network.