servers/losurdo/networking/nftables.nix

   1 { pkgs, lib, config, servers, ... }:
   2 let
   3   inherit (builtins) hasAttr readFile;
   4   inherit (pkgs.lib) unlinesAttrs;
   5   inherit (config.users) users groups;
   6 in
   7 {
   8 networking.firewall.enable = false;
   9 security.lockKernelModules = false;
  10 systemd.services.disable-kernel-module-loading.after = [ "nftables.service" ];
  11 # echo -e "$(nix eval servers.losurdo.config.networking.nftables.ruleset)"
  12 # nft list ruleset
  13 networking.nftables = {
  14   enable = true;
  15   ruleset = lib.mkBefore ''
  16     table inet filter {
  17       chain net2fw {
  18         # Some .nix append rules here with: add rule inet filter net2fw ...
  19       }
  20       chain fw2net {
  21         tcp dport {80,443} counter accept comment "HTTP"
  22         udp dport 123 skuid ${users.systemd-timesync.name} counter accept comment "NTP"
  23         tcp dport 9418 counter accept comment "Git"
  24
  25         # Some .nix append rules here with: add rule inet filter fw2net ...
  26       }
  27
  28       chain input {
  29         type filter hook input priority 0
  30         policy drop
  31
  32         iifname lo accept
  33
  34         # accept traffic already established
  35         ct state {established, related} accept
  36         ct state invalid drop
  37
  38         # admin services
  39         tcp dport 22 counter accept comment "SSH"
  40         udp dport 60000-61000 counter accept comment "Mosh"
  41
  42         # ICMP
  43         ip6 nexthdr icmpv6 icmpv6 type { destination-unreachable, packet-too-big, time-exceeded, parameter-problem, nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert, mld-listener-query, nd-router-solicit } accept
  44         ip protocol icmp   icmp   type { destination-unreachable, router-advertisement, time-exceeded, parameter-problem } accept
  45
  46         # allow "ping"
  47         ip6 nexthdr icmpv6 icmpv6 type echo-request accept
  48         ip protocol icmp   icmp   type echo-request accept
  49
  50         # Some .nix append gotos here with: add rule inet filter input iffname ... goto ...
  51       }
  52       chain output {
  53         type filter hook output priority 0
  54         policy drop
  55
  56         oifname lo accept
  57
  58         ct state {related,established} accept
  59         ct state invalid drop
  60
  61         icmp type echo-request counter accept comment "Ping"
  62         tcp dport 22 counter accept comment "SSH"
  63
  64         # Some .nix append gotos here with: add rule inet filter output oifname ... goto ...
  65       }
  66       chain forward {
  67         type filter hook forward priority 0
  68         policy drop
  69         drop
  70       }
  71     }
  72   '';
  73 };
  74 }