wireshark-extcap: wrap wireshark with extcap programs

pkgs/default/ieee-802-15-4-sniffer/README.md

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+This implements an ieee 802.15.4 sniffer in the 2.4ghz band using O-QPSK demod. The main entrypoint implements the wireshark extcap protocol, which will make it appear in the list of interfaces if it's located in its `lib/extpath` folder, or if it's referenced by `WIRESHARK_EXTCAP_DIR`.

pkgs/default/wireshark-extcap/README.md

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+The default Wireshark only looks for extcap programs within a few specific locations, this creates a wrapper in order to expose specific extcap programs to Wireshark.

pkgs/default/wireshark-extcap/package.nix

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+{ lib
+, wireshark
+, symlinkJoin
+, makeWrapper
+, onlyBin
+, extCapPackages ? []
+
+# Whether to include the extcap binaries provided by this repository
+, includeExtCaps ? true
+, ieee-802-15-4-sniffer ? null
+, ice9-bluetooth-sniffer ? null
+ }:
+
+let
+  extCapDir = symlinkJoin {
+    name = "wireshark-extcap-dir";
+    paths = lib.optionals includeExtCaps [ ieee-802-15-4-sniffer ice9-bluetooth-sniffer ] ++ extCapPackages;
+    postBuild = ''
+      # Link the builtin extcap programs because wireshark doesn't look in its own lib directory 
+      # if the env var is set
+      cp -vs ${wireshark}/lib/wireshark/extcap/* $out/bin
+
+      # Some programs might've been wrapped and have a hidden `.orig.wrapped` file that we don't want
+      # wireshark calling into
+      rm -f $out/bin/.[!.]*
+    '';
+  };
+in
+
+symlinkJoin {
+  name = "wireshark-wrapped";
+  paths = [ wireshark ];
+  nativeBuildInputs = [ makeWrapper ];
+  postBuild = ''
+  for file in $out/bin/*; do
+    wrapProgram $file --prefix WIRESHARK_EXTCAP_DIR : ${onlyBin extCapDir}/bin
+  done
+  '';
+  meta = wireshark.meta;
+}