iiab/roles/2-common/tasks/network.yml

- name: '2021-07-27: SEE ALSO ~3 networking packages EARLIER installed by https://github.com/iiab/iiab/blob/master/roles/1-prep/tasks/raspberry_pi.yml'
  meta: noop

- name: '2021-07-27: SEE ALSO ~4 networking packages EARLIER installed by https://github.com/iiab/iiab/blob/master/roles/2-common/tasks/packages.yml'
  meta: noop

- name: Install package networkd-dispatcher (OS's other than RaspiOS)
  package:
    name: networkd-dispatcher    # Dispatcher service for systemd-networkd connection status changes
    state: present
  when: not is_raspbian

- name: 'Install network packages: hostapd, iproute2, iptables-persistent, netmask -- later used by https://github.com/iiab/iiab/tree/master/roles/network'
  package:
    name:
      - hostapd                # IEEE 802.11 AP and IEEE 802.1X/WPA/WPA2/EAP Authenticator -- has its service masked out of the box, and only used when IIAB's network roles detects the presence of WiFi and an AP is desired
      - iproute2               # 2021-07-27: RaspiOS installs this regardless -- the new networking and traffic control tools, meant to replace net-tools
      - iptables-persistent    # Boot-time loader for netfilter rules, iptables (firewall) plugin -- however Netfilter / nftables is ever moving forward so keep an eye on it!
      - netmask                # Handy utility -- helps determine network masks
    state: present

# 2021-08-17: Debian ignores this, according to 2013 post:
# https://serverfault.com/questions/511099/debian-ignores-etc-network-if-pre-up-d-iptables
# - name: Install /etc/network/if-pre-up.d/iptables from template (0755)
#   template:
#     src: iptables
#     dest: /etc/network/if-pre-up.d/iptables
#     mode: '0755'

# Ongoing rework (e.g. PR #2652) arising from ansible.posix collection changes:
- name: "Use 'sysctl' to set 'kernel.core_uses_pid: 1' + 4 network settings in /etc/sysctl.conf -- e.g. disabling IPv6 (this might be overkill, as IPv6 should really only be disabled on the LAN side, i.e. br0)"
  sysctl:    # Places these settings in /etc/sysctl.conf, to survive reboot
    name: "{{ item.name }}"
    value: "{{ item.value }}"
  with_items:
    - { name: 'net.ipv4.ip_forward', value: '1' }  # Masquerading LAN->Internet
    - { name: 'net.ipv4.conf.default.rp_filter', value: '1' }
    - { name: 'net.ipv4.conf.default.accept_source_route', value: '0' }
    #- { name: 'kernel.sysrq', value: '1' }             # OS values differ, Ok?
    - { name: 'kernel.core_uses_pid', value: '1' }
    #- { name: 'net.ipv4.tcp_syncookies', value: '1' }  # Very standard in 2020
    #- { name: 'kernel.shmmax', value: '268435456' }    # OS values differ, Ok?
    - { name: 'net.ipv6.conf.all.disable_ipv6', value: '1' }    # IPv6 disabled
    #- { name: 'net.ipv6.conf.default.disable_ipv6', value: '1' }    # AUTO-SET
    #- { name: 'net.ipv6.conf.lo.disable_ipv6', value: '1' }         # BY ABOVE