mirror of
https://github.com/cryptexctl/cursed-ping.git
synced 2025-07-26 20:20:32 +00:00
initial
This commit is contained in:
Alexey Novikov
commit
fa756500d3
3
.gitignore
vendored
Normal file
3
.gitignore
vendored
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@ -0,0 +1,3 @@
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pinger_bpf*
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cursed-ping
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result
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60
flake.lock
generated
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60
flake.lock
generated
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@ -0,0 +1,60 @@
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{
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"nodes": {
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"flake-utils": {
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"inputs": {
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"systems": "systems"
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},
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"locked": {
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"lastModified": 1731533236,
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"narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
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"owner": "numtide",
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"repo": "flake-utils",
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"rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
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"type": "github"
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},
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"original": {
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"owner": "numtide",
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"repo": "flake-utils",
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"type": "github"
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}
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},
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"nixpkgs": {
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"locked": {
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"lastModified": 1738680400,
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"narHash": "sha256-ooLh+XW8jfa+91F1nhf9OF7qhuA/y1ChLx6lXDNeY5U=",
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"owner": "NixOS",
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"repo": "nixpkgs",
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"rev": "799ba5bffed04ced7067a91798353d360788b30d",
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"type": "github"
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},
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"original": {
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"id": "nixpkgs",
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"ref": "nixos-unstable",
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"type": "indirect"
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}
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},
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"root": {
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"inputs": {
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"flake-utils": "flake-utils",
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"nixpkgs": "nixpkgs"
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}
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},
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"systems": {
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"locked": {
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"lastModified": 1681028828,
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"narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
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"owner": "nix-systems",
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"repo": "default",
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"rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
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"type": "github"
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},
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"original": {
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"owner": "nix-systems",
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"repo": "default",
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"type": "github"
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}
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}
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},
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"root": "root",
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"version": 7
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}
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64
flake.nix
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64
flake.nix
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@ -0,0 +1,64 @@
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{
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description = "cursed ping";
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inputs = {
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nixpkgs.url = "nixpkgs/nixos-unstable";
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flake-utils.url = "github:numtide/flake-utils";
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};
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outputs = {
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self,
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nixpkgs,
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flake-utils,
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...
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}:
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{
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overlays.default = final: prev: {
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inherit (self.packages.${prev.system}) bpf2go;
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};
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} // flake-utils.lib.eachDefaultSystem (system: let
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pkgs = import nixpkgs {
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inherit system;
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overlays = [ self.overlays.default ];
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};
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in {
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packages = {
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bpf2go = pkgs.buildGoModule rec {
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pname = "bpf2go";
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version = "0.17.2";
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src = pkgs.fetchFromGitHub {
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owner = "cilium";
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repo = "ebpf";
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rev = "v${version}";
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hash = "sha256-lIJsITwdt6PuTMEHXJekBKM2rgCdPJF+i+QHt0jBgp8=";
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};
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vendorHash = "sha256-Ygljpp5GVM2EbD51q1ufqA6z5yJnrXVEfVLIPrxfm18=";
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subPackages = [ "cmd/bpf2go" ];
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doCheck = false;
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};
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pinger = pkgs.buildGoModule rec {
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pname = "cursed-ping";
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version = "1";
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src = ./.;
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vendorHash = "sha256-RxmMgiMATpO31VP85dlkOXl/nLbVD5W1dfWHhuGKcME=";
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deleteVendor = true;
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ldflags = ["-s -w"];
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env.CGO_ENABLED = 0;
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nativeBuildInputs = with pkgs; [clang bpftools libllvm linuxHeaders bpf2go glibc_multi libbpf];
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hardeningDisable = [ "all" ];
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buildInputs = nativeBuildInputs;
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postConfigure = ''
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go generate ./...
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'';
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meta = with pkgs.lib; {
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description = "cursed ping";
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license = licenses.wtfpl;
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};
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};
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};
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formatter = pkgs.alejandra;
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});
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}
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8
go.mod
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8
go.mod
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module github.com/x3lfyn/cursed-ping
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go 1.23.3
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require (
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github.com/cilium/ebpf v0.17.1 // indirect
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golang.org/x/sys v0.26.0 // indirect
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)
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4
go.sum
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4
go.sum
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github.com/cilium/ebpf v0.17.1 h1:G8mzU81R2JA1nE5/8SRubzqvBMmAmri2VL8BIZPWvV0=
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github.com/cilium/ebpf v0.17.1/go.mod h1:vay2FaYSmIlv3r8dNACd4mW/OCaZLJKJOo+IHBvCIO8=
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golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
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golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
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56
main.go
Normal file
56
main.go
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package main
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import (
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"errors"
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"fmt"
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"log"
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"net"
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"os"
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"os/signal"
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"github.com/cilium/ebpf"
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"github.com/cilium/ebpf/link"
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)
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func main() {
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if len(os.Args) < 2 {
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log.Fatalf("specify a network interface")
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}
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ifaceName := os.Args[1]
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iface, err := net.InterfaceByName(ifaceName)
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if err != nil {
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log.Fatalf("lookup network iface %q: %s", ifaceName, err)
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}
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var objs pingerObjects
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if err := loadPingerObjects(&objs, nil); err != nil {
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var verr *ebpf.VerifierError
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if errors.As(err, &verr) {
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fmt.Printf("%+v\n", verr)
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}
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}
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defer objs.Close()
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link, err := link.AttachXDP(link.XDPOptions{
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Program: objs.Pinger,
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Interface: iface.Index,
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})
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if err != nil {
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log.Fatal("attaching XDP:", err)
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}
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defer link.Close()
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log.Printf("attached to %s", ifaceName)
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stop := make(chan os.Signal, 5)
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signal.Notify(stop, os.Interrupt)
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for {
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select {
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case <-stop:
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log.Print("received signal, exiting..")
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return
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}
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}
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}
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122
xdp.c
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122
xdp.c
Normal file
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/bpf.h>
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#include <linux/icmp.h>
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#include <bpf/bpf_helpers.h>
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#include <linux/in.h>
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#include <bpf/bpf_endian.h>
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#define bpf_memcpy __builtin_memcpy
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__attribute__((__always_inline__)) static inline __u16 csum_fold_helper(
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__u64 csum) {
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int i;
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#pragma unroll
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for (i = 0; i < 4; i++) {
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if (csum >> 16)
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csum = (csum & 0xffff) + (csum >> 16);
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}
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return ~csum;
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}
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// https://github.com/AirVantage/sbulb/blob/master/sbulb/bpf/checksum.c#L21
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__attribute__((__always_inline__))
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static inline void update_csum(__u64 *csum, __be32 old_addr,__be32 new_addr ) {
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// ~HC
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*csum = ~*csum;
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*csum = *csum & 0xffff;
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// + ~m
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__u32 tmp;
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tmp = ~old_addr;
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*csum += tmp;
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// + m
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*csum += new_addr;
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// then fold and complement result !
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*csum = csum_fold_helper(*csum);
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}
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__attribute__((__always_inline__))
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static inline void recalc_icmp_csum(struct icmphdr* hdr, __be32 old_value, __be32 new_value) {
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__u64 csum = hdr->checksum;
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update_csum(&csum, old_value, new_value);
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hdr->checksum = csum;
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}
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__attribute__((__always_inline__))
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static inline void recalc_ip_csum(struct iphdr* hdr, __be32 old_value, __be32 new_value) {
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__u64 csum = hdr->check;
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update_csum(&csum, old_value, new_value);
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hdr->check = csum;
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}
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SEC("xdp")
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int pinger(struct xdp_md* ctx) {
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct ethhdr *eth = data;
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if ((void *)(eth + 1) > data_end) {
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return XDP_PASS;
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}
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if (bpf_ntohs(eth->h_proto) != ETH_P_IP) {
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return XDP_PASS;
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}
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struct iphdr *iph = (void*)(eth + 1);
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if ((void*)(iph + 1) > data_end) {
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return XDP_PASS;
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}
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if (iph->protocol != IPPROTO_ICMP) {
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return XDP_PASS;
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}
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struct icmphdr* icmphdr = (void*)(iph + 1);
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if ((void*)(icmphdr + 1) > data_end) {
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return XDP_PASS;
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}
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if (icmphdr->type != 8) {
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return XDP_PASS;
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}
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__u8 tmp_mac[ETH_ALEN];
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bpf_memcpy(tmp_mac, eth->h_dest, ETH_ALEN);
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bpf_memcpy(eth->h_dest, eth->h_source, ETH_ALEN);
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bpf_memcpy(eth->h_source, tmp_mac, ETH_ALEN);
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__u32 tmp_ip = iph->daddr;
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iph->daddr = iph->saddr;
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iph->saddr = tmp_ip;
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icmphdr->type = 0;
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recalc_icmp_csum(icmphdr, 8, icmphdr->type);
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__u64* ts_secs = (void*)(icmphdr + 1);
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__u64* ts_nsecs = (void*)(icmphdr + 1) + sizeof(__u64);
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if ((void*)ts_nsecs + sizeof(__u64) <= data_end) {
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__u64 old_secs = *ts_secs;
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__u64 old_nsecs = *ts_nsecs;
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*ts_secs -= bpf_get_prandom_u32() % 500;
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*ts_nsecs -= bpf_get_prandom_u32();
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recalc_icmp_csum(icmphdr, old_secs, *ts_secs);
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recalc_icmp_csum(icmphdr, old_nsecs, *ts_nsecs);
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}
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__u8 old_ttl = iph->ttl;
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iph->ttl = bpf_get_prandom_u32() % 200 + 40;
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recalc_ip_csum(iph, old_ttl, iph->ttl);
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__be16 old_seq = icmphdr->un.echo.sequence;
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icmphdr->un.echo.sequence = bpf_htons(bpf_get_prandom_u32() % 1000);
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recalc_icmp_csum(icmphdr, old_seq, icmphdr->un.echo.sequence);
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return XDP_TX;
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}
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char LICENSE[] SEC("license") = "GPL";
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