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Questions tagged [netlink]

Netlink is a socket based inter process communication protocol for Linux systems. It is currently the preferred way, as of 2.6, of communicating with user space from the kernel.

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How to receive Kernel uevents with Netlink socket?

I'm trying to receive uevent from the kernel via a netlink socket, when a USB device is (dis)connects. I have a python script that does the same job and it works, but I need the same functionality in C. So far I have this: #include…
Lasse Meyer
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Get CAN bitrate

I want to read the currently configured CAN bitrate of my socketcan socket in C++. I can see the bitrate with ip -det link show can0: 9: can0: mtu 16 qdisc pfifo_fast state UP mode DEFAULT group default qlen 10 link/can …
Laurenz
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Linux C++ Network Session monitor

I'm trying to monitor the network sessions on server withe event driven programming (and not polling on /proc/net/tcp or udp). I was able to find this article but it only provide one time look at the current state and not an event on each change…
Amir Rossert
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Linux suspend/resume operations' userspace notification

I'm working on an embedded linux platform. When I do "echo "mem" > /sys/power/state", system will suspend. I know that kernel and driver can know that suspend operation's coming. But would it be possible that a user space process or application can…
uestclx
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Can kernel module take initiative to send message to user space with netlink?

I am trying to run following code, which was copied from here. I have made few changes to run it with older kernel versions. When I insert kernel module, nlmsg_multicast() fails and logs as nlmsg_multicast() error: -3 in /var/log/messages. While…
Nitinkumar Ambekar
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Vlan interface details using NETLINK

I understand that new interface addition can be detected using RTE_NEWLINK message type in NETLINK. Netlink sends a message with which we can get index and name of the interface using (if_indextoname & if_nametoindex). My question is , if we add…
user1762571
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How to suppress multiple netlink events?

I have been using this code as a sample to receive interface up/down events on a Linux machine. I am able to receive the events correctly but when an interface comes up from a previous down state, I receive multiple netlink events like this: Event…
iqstatic
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Netlink Multicast Kernel Group

The task I am trying to achieve is actually quite simple (multicast the string "TEST" to a userland daemon), but the kernel module doesn't compile. It stops with the error: passing argument 4 of ‘genlmsg_multicast_allns’ makes integer from pointer…
user4122787
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Get all link and address information when listenning to a PF_NETLINK socket

I've written a peace of code that notifies me whenever relevant (to me) networking information changes (mainly listenning to RTM_NEWADDR, RTM_DELADDR, RTM_NEWLINK and RTM_DELLINK. this works pretty fine, each time I unplug, change ip or whatsoever I…
Ayman Khamouma
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How are netlink sockets in the Linux kernel different from polling from userland?

I have doubt about the functioning of netlink socket in kernel-application interaction context. As I have read that netlink socket is used for event based notification from kernel to application. The benefit of this is Application is not required to…
Rahul
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Is it possible to communicate between two linux kernel module via netlink?

As all know, netlink it's user/kernel space communication mechanism. I want to communicate from my kernel module to an another. Another kernel module already has the netlink interface. Is it possible to make connection from kernel module to netlink,…
AlexeyPerevalov
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NetlinkListener and NetlinkEvent error messages

My application does not break during Runtime. However, the following error messages always show up NetlinkListener: ignoring non-kernel netlink multicast message NetlinkEvent: NetlinkEvent::FindParam(): Parameter 'UDEV_LOG' not found The app I'm…
nanoeng
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cannot understand this "message sequence mismatch error"

I've used the program answered in this link with some modifications. Below is my modified code: #include #include #include #include #include…
ram
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Different package present in /usr/lib/x86_64-linux-gnu/

I'm running this command nl-qdisc-add --dev=veth-host --parent=root plug --limit=32768 It throws an error of Error: Unable to load module "/usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so": /usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so: cannot…
user13145713
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Network-packets buffering in kernel qdiscs module

I want to buffer output packets originating from a container's network interface. This netlink library file named sch_plug.c https://code.woboq.org/linux/linux/net/sched/sch_plug.c.html looks like it can solve the problem but i'm finding it hard to…
user13145713
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