+/* Table summarizing what is the decision to prefer IPv4 or IPv6
+ * based their values.
+ *
+ * | ipv4_address | ipv6_address | Chosen IP | Color |
+ * |--------------|--------------|-----------|-------------------|
+ * | NULL | NULL | None | bad (red) |
+ * | NULL | no IP | IPv6 | degraded (orange) |
+ * | NULL | ::1/128 | IPv6 | ok (green) |
+ * | no IP | NULL | IPv4 | degraded |
+ * | no IP | no IP | IPv4 | degraded |
+ * | no IP | ::1/128 | IPv6 | ok |
+ * | 127.0.0.1 | NULL | IPv4 | ok |
+ * | 127.0.0.1 | no IP | IPv4 | ok |
+ * | 127.0.0.1 | ::1/128 | IPv4 | ok |
+ */