role/dns: configure NSD as the stealth master with 2 domains

* Add "network" and "nsd" variables
* Install and configure NSD as the authoritative stealth master server
* Allow notify and transfer to slave masters:
  - freedns.afraid.org
  - 1984hosting.com
* Add preliminary zone files for domains:
  - 233233.xyz
  - 1314233.xyz

6 files changed, 265 insertions, 0 deletions

diff --git a/host_vars/vultr b/host_vars/vultr
index 630d3a2..7c683b5 100644
--- a/host_vars/vultr
+++ b/host_vars/vultr
@@ -3,10 +3,30 @@ ansible_ssh_host: vultr.liwt.net
 ansible_ssh_port: 8864
 ansible_python_interpreter: /usr/local/bin/python2.7
 
+network:
+  interface: vtnet0
+  ipv4:
+    address: 45.77.201.74
+    netmask: 255.255.254.0
+    gateway: 45.77.200.1
+  ipv6:
+    address: 2001:19f0:5:3166::c0f:fee
+    prefixlen: 64
+
 shadowsocks:
   server_port: 8989
   password: "???"
   method: "chacha20-ietf-poly1305"
   nameserver: "8.8.8.8"
 
+nsd:
+  # Secret key for TSIGs that secure zone transfers.
+  key_name: nsdkey
+  # Generate by e.g.: dd if=/dev/random bs=32 count=1 | openssl base64
+  key_secret: cuE2ZtReggzlaVzCmD0VWAnZp494x0KnPG4pSTU63LE=
+  # Domains/zones
+  zones:
+    - 233233.xyz
+    - 1314233.xyz
+
 # vim: set ft=yaml sw=2: #
diff --git a/roles/dns/handlers/main.yml b/roles/dns/handlers/main.yml
new file mode 100644
index 0000000..aab63c8
--- /dev/null
+++ b/roles/dns/handlers/main.yml
@@ -0,0 +1,6 @@
+---
+- name: restart-unbound
+  command: rcrestart unbound
+
+- name: restart-nsd
+  command: rcrestart nsd
diff --git a/roles/dns/tasks/main.yml b/roles/dns/tasks/main.yml
index 59522a8..6712c37 100644
--- a/roles/dns/tasks/main.yml
+++ b/roles/dns/tasks/main.yml
@@ -20,11 +20,13 @@
   command: >
     fetch -o /usr/local/etc/unbound/root.hints
     "https://www.internic.net/domain/named.cache"
+  notify: restart-unbound
 
 - name: unbound - copy configuration
   copy:
     src: unbound.conf
     dest: /usr/local/etc/unbound/unbound.conf
+  notify: restart-unbound
 
 - name: unbound - enable and start service
   command: rcenable unbound
@@ -33,3 +35,33 @@
   copy:
     src: resolv.conf
     dest: /etc/resolv.conf
+
+- name: NSD - copy configuration
+  template:
+    src: nsd.conf.j2
+    dest: /usr/local/etc/nsd/nsd.conf
+  notify: restart-nsd
+
+- name: NSD - check existence of control key/cert
+  stat:
+    path: /usr/local/etc/nsd/nsd_control.key
+  register: stat_result
+
+- name: NSD - generate self-signed key/cert for control
+  command: nsd-control-setup
+  when: stat_result.stat.exists == False
+
+- name: NSD - create zones directory
+  file:
+    path: /usr/local/etc/nsd/zones
+    state: directory
+
+- name: NSD - copy zone files
+  template:
+    src: "zones/{{ item }}.zone.j2"
+    dest: "/usr/local/etc/nsd/zones/{{ item }}.zone"
+  with_items: "{{ nsd.zones }}"
+  notify: restart-nsd
+
+- name: NSD - enable and start service
+  command: rcenable nsd
diff --git a/roles/dns/templates/nsd.conf.j2 b/roles/dns/templates/nsd.conf.j2
new file mode 100644
index 0000000..9110210
--- /dev/null
+++ b/roles/dns/templates/nsd.conf.j2
@@ -0,0 +1,148 @@
+#
+# /usr/local/etc/nsd/nsd.conf
+# See nsd.conf(5)
+#
+# References
+# ----------
+# * NSD DNS Server Tutorial
+#   https://calomel.org/nsd_dns.html
+# * Host Your own DNS, without Sacrificing Reliability
+#   https://blog.tom-fitzhenry.me.uk/2012/12/host-your-own-dns-without-sacrificing-reliability.html
+# * Stealth (a.k.a. DMZ or Hidden Master) Name Server
+#   http://www.zytrax.com/books/dns/ch4/#stealth
+# * Free Secondary/slave DNS services
+#   http://www.frankb.us/dns/
+# * Free Secondary (slave) DNS
+#   https://bornoe.org/blog/2015/10/free-secondary-slave-dns/
+#
+#
+# Aaron LI
+#
+
+# NOTE:
+# Authoritative master server in *stealth* mode, i.e., hidden master.
+#
+# Due to the importance of the DNS, many registrars require that at least 2
+# name servers are provided from different machines or even from different
+# countries.  Maybe you could create another glue record with the same IP
+# address to fool the registrar, but some registrars may further check the
+# IP addresses.  Nevertheless, it is highly unrecommended to host your own
+# DNS on single machine, and secondary/slave DNS services should be used.
+# One can even configure a hidden master DNS with several slaves, which
+# can greatly reduce the traffic to the (small) master DNS, since only the
+# configured slaves have access to it, and the better security (avoid DDoS).
+
+server:
+    # Specify the interfaces to bind.
+    # Default are the wildcard interfaces 0.0.0.0 and ::0).
+    ip-address: {{ network.ipv4.address }}
+    ip-address: {{ network.ipv6.address }}
+
+    # Use the reuseport socket option for performance.
+    # Default: no.
+    reuseport: yes
+
+    # Listen on IPv4 connections
+    do-ip4: yes
+
+    # Listen on IPv6 connections
+    do-ip6: yes
+
+    # The file used to store the compiled zone information.
+    # If set to "" then no disk-database is used, less memory used
+    # but zone updates are not (immediately) spooled to disk.
+    #database: "/var/db/nsd/nsd.db"
+    database: ""
+
+    # The directory for "zonefile" files.  The daemon chdirs here.
+    #zonesdir: "/usr/local/etc/nsd"
+
+    # The list of dynamically added zones.
+    #zonelistfile: "/var/db/nsd/zone.list"
+
+    # Don't answer VERSION.BIND and VERSION.SERVER CHAOS class queries
+    hide-version: yes
+
+    # Identify the server (CH TXT ID.SERVER entry)
+    identity: ""
+
+    # Statistics are produced every number of seconds. Prints to log.
+    # Default is 0, meaning no statistics are produced.
+    # NOTE: requires BIND 8 statistics, which is disabled in the package
+    #statistics: 7200
+
+    # Verbosity level (0, 1, 2).
+    # Level 0 will print warnings and errors, and other events that are
+    # important to keep NSD running.
+    verbosity: 0
+
+    # Log messages to file.  Default to stderr and syslog (with
+    # facility LOG_DAEMON).  stderr disappears when daemon goes to bg.
+    #logfile: "/var/log/nsd.log"
+
+
+# Remote control config section.
+#
+remote-control:
+    # Enable remote control with nsd-control(8) here.
+    control-enable: yes
+
+    # Interfaces listened to for control.  Default is on localhost.
+    control-interface: 127.0.0.1
+    control-interface: ::1
+
+    # Server and nsd-control key and certificate files for remote control.
+    # Set up the keys and certificates with nsd-control-setup.
+    server-key-file: "/usr/local/etc/nsd/nsd_server.key"
+    server-cert-file: "/usr/local/etc/nsd/nsd_server.pem"
+    control-key-file: "/usr/local/etc/nsd/nsd_control.key"
+    control-cert-file: "/usr/local/etc/nsd/nsd_control.pem"
+
+
+# Secret keys for TSIGs that secure zone transfers.
+# You could include: "secret.keys" and put the "key:" statements there,
+# and give that file special access control permissions.
+#
+key:
+    # The key name is used to refer to this key in the access control list,
+    # and must be correct for TSIG to work.
+    name: "{{ nsd.key_name }}"
+
+    # The base64-encoded shared secret.
+    # e.g.: dd if=/dev/random bs=32 count=1 | openssl base64
+    secret: "{{ nsd.key_secret }}"
+
+
+# Patterns have zone configuration that are shared by one or more zones.
+#
+pattern:
+    # Name by which the pattern is referred to
+    name: "stealth_zones"
+
+    # The zonefile for the zones that use this pattern.
+    # If relative then from the zonesdir (inside the chroot).
+    # the name is processed: %s - zone name (as appears in zone:name).
+    zonefile: "zones/%s.zone"
+
+    # Use "%s" to use the name of the zone to track its statistics from
+    # nsd-control stats and stats_noreset.
+    zonestats: "%s"
+
+    # Notify these slaves when the master zone changes
+    notify: 174.37.196.55   NOKEY  # freedns.afraid.org
+    notify: 93.95.224.6     NOKEY  # 1984hosting.com
+
+    # Allow these IPs and TSIG to transfer zones.
+    provide-xfr: 174.37.196.55  NOKEY  # freedns.afraid.org
+    provide-xfr: 93.95.224.6    NOKEY  # 1984hosting.com
+
+
+# Fixed zone entries.  Here you can config zones that cannot be deleted.
+# Zones that are dynamically added and deleted are put in the zonelist file.
+#
+{% for zone in nsd.zones %}
+zone:
+    name: "{{ zone }}"
+    include-pattern: "stealth_zones"
+
+{% endfor %}
diff --git a/roles/dns/templates/zones/1314233.xyz.zone.j2 b/roles/dns/templates/zones/1314233.xyz.zone.j2
new file mode 100644
index 0000000..ede92da
--- /dev/null
+++ b/roles/dns/templates/zones/1314233.xyz.zone.j2
@@ -0,0 +1,21 @@
+$ORIGIN 1314233.xyz.
+$TTL 1h
+
+@           IN  SOA     ns.1314233.xyz.  admin.1314233.xyz.  (
+                        2018022120  ; serial number
+                        1d          ; refresh
+                        2h          ; retry
+                        4w          ; expire
+                        1h          ; minimum TTL
+                        )
+
+@           IN  NS      ns2.afraid.org.
+
+@           IN  A       {{ network.ipv4.address }}
+@           IN  AAAA    {{ network.ipv6.address }}
+
+www         IN  CNAME   www.233233.xyz.
+g           IN  CNAME   g.233233.xyz.
+zw          IN  CNAME   zw.233233.xyz.
+
+; vim: set ft=bindzone :
diff --git a/roles/dns/templates/zones/233233.xyz.zone.j2 b/roles/dns/templates/zones/233233.xyz.zone.j2
new file mode 100644
index 0000000..9a71750
--- /dev/null
+++ b/roles/dns/templates/zones/233233.xyz.zone.j2
@@ -0,0 +1,38 @@
+$ORIGIN 233233.xyz.
+$TTL 1h
+
+; WARNING:
+; A CNAME record is NOT allowed to coexist with *any other* data!
+; Therefore one can't have a CNAME Record at the zone root, because
+; the zone root must have two mandatory records: SOA and NS.
+;
+; According to the specification: if a CNAME RR is present at a node,
+; no other data should be present; this ensures that the data for a
+; canonical name and its aliases cannot be different.  This rule also
+; insures that a cached CNAME can be used without checking with an
+; authoritative server for other RR types.
+
+@           IN  SOA     ns.233233.xyz.  admin.233233.xyz.  (
+                        2018022123  ; serial number
+                        1d          ; refresh
+                        2h          ; retry
+                        4w          ; expire
+                        1h          ; minimum TTL
+                        )
+
+@           IN  NS      ns2.afraid.org.
+
+;@           IN  MX  10  mail.233233.xyz.
+
+@           IN  A       {{ network.ipv4.address }}
+@           IN  AAAA    {{ network.ipv6.address }}
+;mail        IN  A       {{ network.ipv4.address }}
+;mail        IN  AAAA    {{ network.ipv6.address }}
+
+www         IN  CNAME   @
+g           IN  CNAME   @
+zw          IN  CNAME   @
+
+;@           IN  TXT     "v=spf1 mx -all"
+
+; vim: set ft=bindzone :