rt1(z9 host): create host and configure networkd and nftables

resources/z9/rt1/nftables/nftables.conf

@@ -0,0 +1,111 @@
+#!/usr/sbin/nft -f
+
+## Variables
+
+# Hosts
+
+
+# Interfaces
+define if_netwan = "netwan"
+define if_netlan = "netlan"
+define if_wg55_management   = "wg55"
+define if_netwan_400_fux_uplink = "netwan.400"
+define if_netlan_51_clients = "netlan.51"
+define if_netlan_52_iot = "netlan.52"
+define if_netlan_53_public = "netlan.53"
+define if_netlan_54_management = "netlan.54"
+
+# Interface Groups
+define wan_ifs = { $if_netwan_400_fux_uplink }
+define lan_ifs = { $if_netlan_51_clients,
+                   $if_netlan_52_iot,
+                   $if_netlan_53_public,
+                   $if_netlan_54_management }
+define v4_exposed_ifs = { $if_netlan_53_public }
+define v6_exposed_ifs = { $if_netlan_53_public }
+define v4_nat_ifs = { $if_netlan_51_clients,
+                      $if_netlan_52_iot,
+                      $if_netlan_54_management }
+
+
+## Rules
+
+table inet reverse-path-forwarding {
+    chain rpf-filter {
+        type filter hook prerouting priority mangle + 10; policy drop;
+
+        # Only allow packets if their source address is routed via their incoming interface.
+        # https://github.com/NixOS/nixpkgs/blob/d9d87c51960050e89c79e4025082ed965e770d68/nixos/modules/services/networking/firewall-nftables.nix#L100
+        fib saddr . mark . iif oif exists accept
+    }
+}
+
+table inet host {
+    chain input {
+        type filter hook input priority filter; policy drop;
+
+        iifname "lo" accept comment "allow loopback"
+
+        ct state invalid drop
+        ct state established,related accept
+
+		    ip protocol icmp accept
+        # ICMPv6
+        # https://datatracker.ietf.org/doc/html/rfc4890#autoid-24
+        # Allowlist consisting of: "Traffic That Must Not Be Dropped" and "Traffic That Normally Should Not Be Dropped"
+        # Error messages that are essential to the establishment and maintenance of communications:
+        icmpv6 type { destination-unreachable, packet-too-big } accept
+        icmpv6 type { time-exceeded } accept
+        icmpv6 type { parameter-problem } accept
+        # Connectivity checking messages:
+        icmpv6 type { echo-request, echo-reply } accept
+        # Address Configuration and Router Selection messages:
+        icmpv6 type { nd-router-solicit, nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert, ind-neighbor-solicit, ind-neighbor-advert } accept
+        # Link-Local Multicast Receiver Notification messages:
+        icmpv6 type { mld-listener-query, mld-listener-report, mld-listener-done, mld2-listener-report } accept
+        # SEND Certificate Path Notification messages:
+        icmpv6 type { 148, 149 } accept
+        # Multicast Router Discovery messages:
+        icmpv6 type { 151, 152, 153 } accept
+
+        # Allow SSH access.
+        tcp dport 22 accept comment "allow ssh access"
+
+        # Allow WireGuard access.
+        udp dport 51820 accept comment "allow WireGuard access"
+
+        # Allow DHCP server access.
+		    iifname { $lan_ifs } udp dport 67 accept comment "allow dhcp server access"
+    }
+}
+
+table ip v4nat {
+    chain prerouting {
+        type nat hook prerouting priority dstnat; policy accept;
+    }
+
+    chain postrouting {
+        type nat hook postrouting priority srcnat; policy accept;
+
+        iifname { $v4_nat_ifs, $if_wg55_management } oifname $wan_ifs masquerade
+    }
+}
+
+table inet forward {
+    chain forward {
+        type filter hook forward priority filter; policy drop;
+
+        ct state invalid drop
+        ct state established,related accept
+
+        # Allow internet access.
+		    iifname { $lan_ifs, $if_wg55_management } oifname $wan_ifs accept comment "allow internet access"
+
+        # Allow access to exposed networks from internet.
+        meta nfproto ipv4 oifname $v4_exposed_ifs accept comment "allow v4 exposed network access"
+        meta nfproto ipv6 oifname $v6_exposed_ifs accept comment "allow v6 exposed network access"
+
+        # Allow clients and managment to most
+        iifname { $if_netlan_51_clients, $if_netlan_54_management, $if_wg55_management } oifname $lan_ifs accept comment "allow clients and managment to lan_ifs"
+    }
+}