wireshark: enable firejail isolation

hosts/common/programs/wireshark.nix

@@ -1,6 +1,24 @@
-{ config, ... }:
+{ config, lib, ... }:
+let
+  cfg = config.sane.programs.wireshark;
+in
 {
-  sane.programs.wireshark.slowToBuild = true;
+  sane.programs.wireshark = {
+    sandbox.method = "firejail";
+    sandbox.extraFirejailConfig = ''
+      # somehow needs `setpcap` (makes these bounding capabilities also be inherited?)
+      # else no interfaces appear on the main page
+      ignore caps.keep dac_override,dac_read_search,net_admin,net_raw
+      caps.keep dac_override,dac_read_search,net_admin,net_raw,setpcap
+    '';
+    slowToBuild = true;
+  };
 
-  programs.wireshark.enable = config.sane.programs.wireshark.enabled;
+  programs.wireshark = lib.mkIf cfg.enabled {
+    # adds a SUID wrapper for wireshark's `dumpcap` program
+    enable = true;
+    package = cfg.package;
+  };
+  # the SUID wrapper can't also be a firejail (idk why? it might be that the binary's already *too* restricted).
+  security.wrappers.dumpcap.source = lib.mkIf cfg.enabled (lib.mkForce "${cfg.package}/bin/.dumpcap-firejailed");
 }