Add role to verify network connectivity (#166)

The added role will check network connectivity from every host in the
provided group to all others. It will use the highest possible data size
for the given MTU to send ping echo requests to conduct this test.

Part of osism/issues#1088

Signed-off-by: Jan Horstmann <[email protected]>

roles/network_connectivity/defaults/main.yml

@@ -0,0 +1,4 @@
+---
+network_connectivity_group: all
+network_connectivity_network_cidr: 127.0.0.0/8
+network_connectivity_ping_count: 1

roles/network_connectivity/meta/main.yml

@@ -0,0 +1,15 @@
+---
+galaxy_info:
+  author: Jan Horstmann
+  description: Role osism.validations.network_connectivity
+  company: OSISM GmbH
+  license: Apache License 2.0
+  min_ansible_version: 2.13.0
+  platforms:
+    - name: Ubuntu
+      versions:
+        - jammy
+  galaxy_tags:
+    - osism
+    - system
+dependencies: []

roles/network_connectivity/tasks/main.yml

@@ -0,0 +1,103 @@
+---
+- name: Assert provided group contains multiple hosts
+  ansible.builtin.assert:
+    that: network_connectivity_group | length > 1
+
+- name: Assert provided network is valid
+  ansible.builtin.assert:
+    that: network_connectivity_network_cidr | ansible.utils.ipaddr
+
+- name: Run ping check with maximum possible length
+  ansible.builtin.command:
+    argv:
+      - /bin/ping
+      # quiet
+      - -q
+      # do not fragment
+      - -M
+      - do
+      # set source IP
+      - -I
+      - "{{ ip_address }}"
+      # use MTU sized packets
+      - -s
+      - "{{ mtu | int - ip_header_size | int - icmp_header_size | int }}"
+      # send specified packet count
+      - -c
+      - "{{ network_connectivity_ping_count }}"
+      - "{{ item }}"
+  vars:
+    ip_version: >-
+      {{
+        'ipv4'
+        if network_cidr | ansible.utils.ipv4 | length > 0
+        else (
+          'ipv6'
+          if network_cidr | ansible.utils.ipv6 | length > 0
+          else
+          None
+        )
+      }}
+    ip_address: >-
+      {{
+        ansible_facts
+        | dict2items
+        | map(attribute='value')
+        | selectattr(ip_version, 'defined')
+        | map(attribute=ip_version)
+        | selectattr('address', 'defined')
+        | map(attribute='address')
+        | ansible.utils.ipaddr(network_cidr)
+        | list
+        | first
+      }}
+    mtu: >-
+      {{
+        ansible_facts
+        | dict2items
+        | map(attribute='value')
+        | selectattr(ip_version, 'defined')
+        | selectattr('mtu', 'defined')
+        | selectattr(ip_version + '.address', 'defined')
+        | selectattr(ip_version + '.address', 'equalto', ip_address)
+        | map(attribute='mtu')
+        | list
+        | first
+      }}
+    ip_header_size: >-
+      {{
+        20
+        if ip_version == 'ipv4'
+        else (
+          40
+          if ip_version == 'ipv6'
+          else
+          None
+        )
+      }}
+    icmp_header_size: '8'
+  loop: >-
+    {{
+      network_connectivity_group
+      | difference([inventory_hostname])
+      | map('extract', hostvars, 'ansible_facts')
+      | map('dict2items')
+      | map('map', attribute='value')
+      | map('selectattr', ip_version, 'defined')
+      | map('map', attribute=ip_version)
+      | map('selectattr', 'address', 'defined')
+      | map('map', attribute='address')
+      | map('ansible.utils.ipaddr', network_cidr)
+      | list
+      | flatten
+    }}
+  register: ping
+  changed_when: False
+
+- name: Assert that ping check was successful
+  ansible.builtin.assert:
+    that: item.rc == 0
+    quiet: True
+  loop: "{{ ping.results }}"
+  loop_control:
+    label: "{{ item.stdout }}"