Add dropworld

.gitignore

@@ -0,0 +1 @@
+result

dropworld/default.nix

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+{clangStdenv, libbpf, ...}: clangStdenv.mkDerivation {
+  name = "dropworld";
+  src = ./.;
+  hardeningDisable = [ "stackprotector" "zerocallusedregs" ];
+  dontFixup = true;
+  buildInputs = [ libbpf ];
+
+  buildPhase = ''
+    clang -O2 -target bpf -g -c dropworld.c -o dropworld.o
+  '';
+
+  installPhase = ''
+    mkdir $out
+    cp dropworld.o $out
+  '';
+}

dropworld/dropworld.c

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+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+SEC("xdp")
+int xdp_drop(struct xdp_md *ctx) {
+    return XDP_DROP; // Drop all packets
+}
+
+char LICENSE[] SEC("license") = "GPL";

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1734649271,
+        "narHash": "sha256-4EVBRhOjMDuGtMaofAIqzJbg4Ql7Ai0PSeuVZTHjyKQ=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d70bd19e0a38ad4790d3913bf08fcbfc9eeca507",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "A very basic flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = inputs: inputs.flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = inputs.nixpkgs.legacyPackages.${system};
+    in
+    {
+      packages.dropworld = pkgs.callPackage ./dropworld {};
+    }
+  );
+}