netlink | Simple netlink library for go | Telnet library

 by   vishvananda Go Version: v1.2.1-beta.2 License: Apache-2.0

kandi X-RAY | netlink Summary

kandi X-RAY | netlink Summary

netlink is a Go library typically used in Networking, Telnet applications. netlink has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can download it from GitHub.

The netlink package provides a simple netlink library for go. Netlink is the interface a user-space program in linux uses to communicate with the kernel. It can be used to add and remove interfaces, set ip addresses and routes, and configure ipsec. Netlink communication requires elevated privileges, so in most cases this code needs to be run as root. Since low-level netlink messages are inscrutable at best, the library attempts to provide an api that is loosely modeled on the CLI provided by iproute2. Actions like ip link add will be accomplished via a similarly named function like AddLink(). This library began its life as a fork of the netlink functionality in docker/libcontainer but was heavily rewritten to improve testability, performance, and to add new functionality like ipsec xfrm handling.
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            kandi-support Support

              netlink has a medium active ecosystem.
              It has 2363 star(s) with 654 fork(s). There are 63 watchers for this library.
              OutlinedDot
              It had no major release in the last 12 months.
              There are 148 open issues and 135 have been closed. On average issues are closed in 127 days. There are 36 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of netlink is v1.2.1-beta.2

            kandi-Quality Quality

              netlink has 0 bugs and 0 code smells.

            kandi-Security Security

              netlink has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              netlink code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              netlink is licensed under the Apache-2.0 License. This license is Permissive.
              Permissive licenses have the least restrictions, and you can use them in most projects.

            kandi-Reuse Reuse

              netlink releases are available to install and integrate.
              Installation instructions, examples and code snippets are available.
              It has 22805 lines of code, 1404 functions and 100 files.
              It has high code complexity. Code complexity directly impacts maintainability of the code.

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            netlink Key Features

            No Key Features are available at this moment for netlink.

            netlink Examples and Code Snippets

            No Code Snippets are available at this moment for netlink.

            Community Discussions

            QUESTION

            xdpoffload attach failed: Invalid argument
            Asked 2022-Feb-10 at 21:09

            When I try to attach a BPF program in XDP offload mode, I get Invalid argument. I get the same error if attach through code or by using bpftool. Here's how I'm attaching using netlink:

            ...

            ANSWER

            Answered 2022-Feb-10 at 21:09

            Mellanox cards support some hardware offload (e.g., flow control rules), but not the offload of BPF programs as far as I know. The only Ethernet adapters out there that support BPF offloading are Netronome's cards.

            One way to check this is to grep for the XDP_SETUP_PROG_HW BPF netdev command in the Linux source code:

            Source https://stackoverflow.com/questions/71070402

            QUESTION

            How to loop over string data type & iterate over it using javascript for displaying the data as list item in html?
            Asked 2022-Feb-09 at 14:11

            I am learning JS by self kindly assist here I am trying to iterate over the below data which is of type string & want to display it in a html file as list items , I am able to get the whole data displayed the problem i am facing is this data I need to display as list items but with the current code it is coming all in a single list item

            JS code below

            ...

            ANSWER

            Answered 2022-Feb-09 at 14:11

            You are looking for something like this:

            Source https://stackoverflow.com/questions/71050680

            QUESTION

            Unable to unload BPF program
            Asked 2022-Feb-09 at 10:03

            I am unable to unload a BPF program from code. I am using the Cilium eBPF library to load the program and netlink to add the BPF function to an interface. Here's what I'm doing:

            ...

            ANSWER

            Answered 2022-Feb-09 at 08:31

            eBPF programs only unload when there are no more references to it(File descriptors, pins), but network links also hold their own references. So to unload the program, you first have to detach it from your network link.

            You can do so by setting the program fd to -1:

            Source https://stackoverflow.com/questions/71043359

            QUESTION

            Keepalived notify not running the script
            Asked 2022-Feb-02 at 01:49

            I am using keepalived from default yum v1.3.5 (03/19,2017), git commit v1.3.5-6-g6fa32f2 on centos 7 (2009)

            The vip is working properly but when I add notify script, it was opening the file but not running it (I guess). This is my config file of my backup. I used root because I read somewhere that keepalived need privilege similar to root (I can be wrong on this)

            ...

            ANSWER

            Answered 2022-Feb-02 at 01:49

            For temporary answer that I used: put a cron to check the current status of server and run the script

            current server status command line

            Source https://stackoverflow.com/questions/70923232

            QUESTION

            Why is sendto returning zero with raw sockets?
            Asked 2022-Jan-11 at 23:42

            The following program uses a PF_PACKET socket to send a TCP SYN packet to web server read from a file which is a list of web server IPv4 addresses - one address per line. The code is quite long because it takes a lot of code to obtain the gateway router MAC and IP address necessary for filling in the ethernet and IP headers. The good news is you can just skip all the functions in the preamble and just go to main which is where the problem is.

            My program works perfectly for the first iteration of the while loop in main. Here is the output:

            ...

            ANSWER

            Answered 2022-Jan-11 at 23:42

            If you are going to use PACKET_TX_RING, then you must play by its rules: that means you can't use the same buffer spot over and over: you must advance to the next buffer location within the ring buffer: build the first packet in slot 0, the second in slot 1, etc. (wrapping when you get to the end of the buffer).

            But you're building every packet in slot 0 (i.e. at ps_header_start) but after sending the first packet, the kernel is expecting the next frame in the subsequent slot. It will never find the (second) packet you created in slot 0 until it has processed all the other slots. But it's looking at slot 1 and seeing that the tp_status in that slot hasn't been set to TP_STATUS_SEND_REQUEST yet so... nothing to do.

            Note that your sendto call is not providing a buffer address to the kernel. That's because the kernel knows where the next packet will come from, it must be in the next slot in the ring buffer following the one you just sent.

            This is why I suggested in your other question that you not use PACKET_TX_RING unless you really need it: it's more complicated to do correctly. It's much easier to just create your frame in a static buffer and call sendto(fd, buffer_address, buffer_len, ...). And if you are going to call sendto for each created frame, there is literally no advantage to using PACKET_TX_RING anyway.

            Source https://stackoverflow.com/questions/70660468

            QUESTION

            Why is my non blocking raw sockets program running so slowly?
            Asked 2022-Jan-11 at 20:59

            I have a program which uses PF_PACKET raw sockets to send TCP SYN packets to a list of web servers. The program reads in a file which has an IPv4 address on each line of a web server. The program is the beginnings of an attempt to connect to multiple servers in a high performance manner. However, currently the program is only sending about 10 packets/second. This despite the program using non blocking socket. It should be running orders of magnitude faster. Any ideas why it could be running so slowly.

            I include a full code listing below. Warning - the code is quite long. That's because it takes a surprisingly large amount of code to get the IP and MAC address of the gateway router. The good news is you can skip all the functions before main because they just do the necessary work of getting the IP and MAC address of the router as well as the local IP address. Anyway, here's the code:

            ...

            ANSWER

            Answered 2022-Jan-11 at 20:59

            If I follow the code correctly, you're redoing a ton of work for every IP address that doesn't need to be redone. Every time through the main loop you're:

            • creating a new packet socket
            • binding it
            • setting up a tx packet ring buffer
            • mmap'ing it
            • sending a single packet
            • unmapping
            • closing the socket

            That's a huge amount of work you're causing the system to do for one packet.

            You should only create one packet socket at the beginning, set up the tx buffer and mmap once, and leave it open until the program is done. You can send any number of packets through the interface without closing/re-opening.

            This is why your top time users are setsockopt, mmap, unmap, etc. All of those operations are heavy in the kernel.

            Also, the point of PACKET_TX_RING is that you can set up a large buffer and create one packet after another within the buffer without making a send system call for each packet. By using the packet header's tp_status field you're telling the kernel that this frame is ready to be sent. You then advance your pointer within the ring buffer to the next available slot and build another packet. When you have no more packets to build (or you've filled the available space in the buffer [i.e. wrapped around to your oldest still-in-flight frame]), you can then make one send/sendto call to tell the kernel to go look at your buffer and (start) sending all those packets.

            You can then start building more packets (being careful to ensure they are not still in use by the kernel -- through the tp_status field).

            That said, if this were a project I were doing, I would simplify a lot - at least for the first pass: create a packet socket, bind it to the interface, build packets one at a time, and use send once per frame (i.e. not bothering with PACKET_TX_RING). If (and only if) performance requirements are so tight that it needs to send faster would I bother setting up and using the ring buffer. I doubt you'll need that. This should go a ton faster without the excess setsockopt and mmap calls.

            Finally, a non-blocking socket is only useful if you have something else to do while you're waiting. In this case, if you have the socket set to be non-blocking and the packet can't be sent because the call would block, the send call will fail and if you don't do something about that (enqueue the packet somewhere, and retry later, say), the packet will be lost. In this program, I can't see any benefit whatsoever to using a non-blocking socket. If the socket blocks, it's because the device transmit queue is full. After that, there's no point in you continuing to produce packets to be sent, you won't be able send those packets either. Much simpler to just block at that point until the queue drains.

            Source https://stackoverflow.com/questions/70644332

            QUESTION

            Temporary failure in name resolution for pod running on kubeadm worker node
            Asked 2021-Dec-08 at 00:08

            I run Kafka inside Kubernetes cluster on VMWare with a ControlPlane and one worker node. From the ControlPlane node my client can communicate with Kafka, but from my worker node this ends up in this error

            ...

            ANSWER

            Answered 2021-Dec-06 at 09:41

            Calico Pod (from the worker node) was complaining that bird: Netlink: Network is down, even it was not crashing

            Source https://stackoverflow.com/questions/70213447

            QUESTION

            TypeError: Cannot read properties of undefined (reading '_value')
            Asked 2021-Nov-17 at 16:16

            I am trying to write the test cases for the below method :-

            ...

            ANSWER

            Answered 2021-Nov-17 at 16:16

            I have added comments below, it should help you.

            Source https://stackoverflow.com/questions/70000998

            QUESTION

            How random is a linux socket file description assignment?
            Asked 2021-Oct-19 at 12:10

            I am writing a C# app to communicate with my wireless card using netlink protocol (via libnl library), in Linux.

            Basically I am mimicking iw's functionality. At this initial state, I want to make sure the initial ported calls results are the same as when debugging the real linux app.

            They are - except for the result I get for acquiring a socket file descriptor, using nl_socket_get_fd. Debugging the app always return a file descriptor valued 3, while my c# app extern call to nl_socket_get_fd always return 26 (even after system boots).

            I remember from a while back I tried to do the same - but mimicking iwlist instead (before noticing it is now deprecated). Debugging also always returned 3 (eventually calling libc's socket function), while debugging my C# port always returned 19.

            Socket's man page says

            socket() creates an endpoint for communication and returns a file descriptor that refers to that endpoint. The file descriptor returned by a successful call will be the lowest-numbered file descriptor not currently open for the process.

            I understand a file descriptor is "randomly" assigned, just found it suspicious that it always return the same number when running in this or that way.

            Is this something to worry about ? Does this indicate my ported code is already not working as expected and moving on will end up creating unexpected results ?

            ...

            ANSWER

            Answered 2021-Oct-19 at 12:10

            The documentation says:

            The file descriptor returned by a successful call will be the lowest-numbered file descriptor not currently open for the process.

            So if your process has open file descriptors 0, 1, and 2, but not 3, it will return 3.

            If your process has open file descriptors 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25, but not 26, it will return 26.

            This is how file descriptors are usually assigned in Linux.

            Source https://stackoverflow.com/questions/69629965

            QUESTION

            Docker: Running container from CLI fails but not from docker desktop, RTENETLINK Oper not permitted
            Asked 2021-Aug-05 at 20:44

            I am learning docker, I downloaded it to my Mac and I was able to run my first docker container from the desktop app. Launching the container for the same image from the command line fails.

            The error log is below showing RteNetLink failure.

            Any thoughts why and how it can be fixed?

            ...

            ANSWER

            Answered 2021-Aug-05 at 20:44

            Launching the container for the same image from the command line doesn't fail, if you look at the logs of the container that you started with Docker Desktop you'll see the same lines.

            What happens is that the centos dockerfile use bash as its default command.

            When you run a container it will attach to stdout and stderr by default but not stdin.

            adding -i will attach stdin.

            adding -t will provide you with a pseudo-tty

            To actually use bash you'll need to provide both : -it

            To sum up, here's how to mimick what Docker Desktop does, starting the container in the background with -d:

            Source https://stackoverflow.com/questions/68672801

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

            Install netlink

            You can use go get command:.

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