From fd78bbb4ce5a9634e1f8c51b82ccfa958e10b45e Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gkleen@yggdrasil.li>
Date: Wed, 4 May 2022 08:35:56 +0200
Subject: sif: nftables

---
 hosts/sif/default.nix |  14 +++--
 hosts/sif/ruleset.nft | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 167 insertions(+), 4 deletions(-)
 create mode 100644 hosts/sif/ruleset.nft

(limited to 'hosts/sif')

diff --git a/hosts/sif/default.nix b/hosts/sif/default.nix
index 11f74373..bcfa1e10 100644
--- a/hosts/sif/default.nix
+++ b/hosts/sif/default.nix
@@ -65,13 +65,19 @@ in {
         "::1" = [ "sif.yggdrasil" "sif" ];
       };
 
-      firewall = {
+      firewall.enable = false;
+      nftables = {
         enable = true;
-        allowedTCPPorts = [ 22 # ssh
-                            8000 # quickserve
-                          ];
+        rulesetFile = ./ruleset.nft;
       };
 
+      # firewall = {
+      #   enable = true;
+      #   allowedTCPPorts = [ 22 # ssh
+      #                       8000 # quickserve
+      #                     ];
+      # };
+
       # wlanInterfaces = {
       #   wlan0 = {
       #     device = "wlp82s0";
diff --git a/hosts/sif/ruleset.nft b/hosts/sif/ruleset.nft
new file mode 100644
index 00000000..62fa90db
--- /dev/null
+++ b/hosts/sif/ruleset.nft
@@ -0,0 +1,157 @@
+define icmp_protos = { ipv6-icmp, icmp, igmp }
+
+table arp filter {
+  limit lim_arp {
+    rate over 50 mbytes/second burst 50 mbytes
+  }
+
+  counter arp-rx {}
+  counter arp-tx {}
+
+  counter arp-ratelimit-rx {}
+  counter arp-ratelimit-tx {}
+
+  chain input {
+    type filter hook input priority filter
+    policy accept
+
+    limit name lim_arp counter name arp-ratelimit-rx drop
+
+    counter name arp-rx
+  }
+
+  chain output {
+    type filter hook output priority filter
+    policy accept
+
+    limit name lim_arp counter name arp-ratelimit-tx drop
+
+    counter name arp-tx
+  }
+}
+
+table inet filter {
+  limit lim_reject {
+    rate over 1000/second burst 1000 packets
+  }
+
+  limit lim_icmp {
+    rate over 50 mbytes/second burst 50 mbytes
+  }
+
+  counter invalid-fw {}
+
+  counter reject-ratelimit-fw {}
+  counter reject-fw {}
+  counter reject-tcp-fw {}
+  counter reject-icmp-fw {}
+
+
+  counter invalid-rx {}
+  counter rx-lo {}
+  counter invalid-local4-rx {}
+  counter invalid-local6-rx {}
+
+  counter icmp-ratelimit-rx {}
+  counter icmp-rx {}
+
+  counter ssh-rx {}
+  counter mosh-rx {}
+  counter wg-rx {}
+  counter yggdrasil-gre-rx {}
+  counter quickserve-rx {}
+
+  counter established-rx {}
+
+  counter reject-ratelimit-rx {}
+  counter reject-rx {}
+  counter reject-tcp-rx {}
+  counter reject-icmp-rx {}
+
+
+  counter tx-lo {}
+
+  counter icmp-ratelimit-tx {}
+  counter icmp-tx {}
+
+  counter ssh-tx {}
+  counter mosh-tx {}
+  counter wg-tx {}
+  counter yggdrasil-gre-tx {}
+  counter quickserve-tx {}
+
+  counter tx {}
+
+
+  chain forward {
+    type filter hook forward priority filter
+    policy drop
+
+
+    ct state invalid log level debug prefix "drop invalid forward: " counter name invalid-fw drop
+
+
+    iifname lo counter name fw-lo accept
+
+
+    limit name lim_reject log level debug prefix "drop forward: " counter name reject-ratelimit-fw drop
+    log level debug prefix "reject forward: " counter name reject-fw
+    meta l4proto tcp ct state new counter name reject-tcp-fw reject with tcp reset
+    ct state new counter name reject-icmp-fw reject
+  }
+
+  chain input {
+    type filter hook input priority filter
+    policy drop
+
+
+    ct state invalid log level debug prefix "drop invalid input: " counter name invalid-rx drop
+    
+
+    iifname lo counter name rx-lo accept
+    iif != lo ip daddr 127.0.0.1/8 counter name invalid-local4-rx reject
+    iif != lo ip6 daddr ::1/128 counter name invalid-local6-rx reject
+
+    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-rx drop
+    meta l4proto $icmp_protos counter name icmp-rx accept
+
+    tcp dport 22 counter name ssh-rx accept
+    udp dport 60001-61000 counter name mosh-rx accept
+
+    tcp dport 8000 counter name quickserve-rx accept
+
+    udp dport 51820-51822 counter name wg-rx accept
+    iifname "yggdrasil-wg-*" meta l4proto gre counter name yggdrasil-gre-rx accept
+
+    ct state {established, related} counter name established-rx accept
+
+
+    limit name lim_reject log level debug prefix "drop input: " counter name reject-ratelimit-rx drop
+    log level debug prefix "reject input: " counter name reject-rx
+    meta l4proto tcp ct state new counter name reject-tcp-rx reject with tcp reset
+    ct state new counter name reject-icmp-rx reject
+  }
+
+  chain output {
+    type filter hook output priority filter
+    policy accept
+
+
+    oifname lo counter name tx-lo accept
+
+    meta l4proto $icmp_protos limit name lim_icmp counter name icmp-ratelimit-tx drop
+    meta l4proto $icmp_protos counter name icmp-tx accept
+
+
+    tcp sport 22 counter name ssh-tx
+    udp sport 60001-61000 counter name mosh-tx
+
+    udp sport 51820-51822 counter name wg-tx
+    iifname "yggdrasil-wg-*" meta l4proto gre counter name yggdrasil-gre-tx
+
+    tcp sport 8000 counter name http-tx accept
+
+
+    counter name tx
+  }
+}
-- 
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