host_firewall: GreenSnow set greensnow_v4 drops inbound new connections of the listed hosts

host_firewall/tasks/main.yml

@@ -59,7 +59,7 @@
     src: "{{ item }}"
     dest: "/etc/systemd/system/{{ item }}"
     mode: "0644"
-  loop: [nft-host.service, nft-host-geo.service, nft-host-geo.timer, nft-host-spamhaus.service, nft-host-spamhaus.timer, nft-host-firehol.service, nft-host-firehol.timer, nft-host-scanners.service, nft-host-scanners.timer]
+  loop: [nft-host.service, nft-host-geo.service, nft-host-geo.timer, nft-host-spamhaus.service, nft-host-spamhaus.timer, nft-host-firehol.service, nft-host-firehol.timer, nft-host-scanners.service, nft-host-scanners.timer, nft-host-greensnow.service, nft-host-greensnow.timer]
   register: firewall_units
 
 - name: Install the rollback script
@@ -287,6 +287,59 @@
         path: /etc/nftables.d/host-scanners.nft
         state: absent
 
+- name: GreenSnow set
+  when: firewall.greensnow
+  block:
+    - name: Install the GreenSnow set updater
+      ansible.builtin.copy:
+        src: nft-host-greensnow
+        dest: /usr/local/sbin/nft-host-greensnow
+        mode: "0755"
+
+    # The rule set includes this file, so a missing one would fail the load at boot.
+    - name: Build the GreenSnow set on first run
+      ansible.builtin.command: /usr/local/sbin/nft-host-greensnow
+      args:
+        creates: /etc/nftables.d/host-greensnow.nft
+
+    - name: Read the GreenSnow set file
+      ansible.builtin.stat:
+        path: /etc/nftables.d/host-greensnow.nft
+      register: firewall_greensnow
+
+    - name: Require non-empty GreenSnow set
+      ansible.builtin.assert:
+        that: firewall_greensnow.stat.exists and firewall_greensnow.stat.size > 0
+        fail_msg: /etc/nftables.d/host-greensnow.nft is missing or empty, refusing to apply the firewall
+      # Check mode neither installs the updater nor builds the set.
+      when: not ansible_check_mode
+
+    - name: Enable the GreenSnow set timer
+      ansible.builtin.systemd:
+        name: nft-host-greensnow.timer
+        enabled: true
+        state: started
+        daemon_reload: "{{ firewall_units is changed }}"
+      # Check mode does not install the unit.
+      ignore_errors: "{{ ansible_check_mode }}"
+
+- name: Stop the GreenSnow set refresh
+  when: not firewall.greensnow
+  block:
+    - name: Disable the GreenSnow set timer
+      ansible.builtin.systemd:
+        name: nft-host-greensnow.timer
+        enabled: false
+        state: stopped
+        daemon_reload: "{{ firewall_units is changed }}"
+      # Check mode does not install the unit.
+      ignore_errors: "{{ ansible_check_mode }}"
+
+    - name: Remove the GreenSnow set file
+      ansible.builtin.file:
+        path: /etc/nftables.d/host-greensnow.nft
+        state: absent
+
 - name: Render the rule set
   ansible.builtin.template:
     src: host.nft.j2