PowerDNS's pipe backend's configuration is included

- also include instructions to run tests

README.md

@@ -1,10 +1,24 @@
-# sslip.io [![ci.nono.io](https://ci.nono.io/api/v1/pipelines/sslip.io/jobs/check-dns/badge)](https://ci.nono.io/?groups=sslip.io)
+# sslip.io
+
+[![ci.nono.io](https://ci.nono.io/api/v1/pipelines/sslip.io/jobs/check-dns/badge)](https://ci.nono.io/?groups=sslip.io)
 
 *sslip.io* is a domain that maps specially-crafted DNS A records to IP addresses
-(e.g. "127-0-0-1.sslip.io" maps to 127.0.0.1). It is similar to, and inspired
+(e.g. "127-0-0-1.sslip.io" maps to 127.0.0.1). It is similar to, inspired by,
-by, [xip.io](http://xip.io/).
+and uses much of the code of [xip.io](http://xip.io/).
 
 Refer to the website ([sslip.io](https://sslip.io)) for more information.
 
 - `document_root/` contains the HTML content of the sslip.io website
-- `ci/` contains the Concourse CI pipeline and task
+- `ci/` contains the [Concourse](https://concourse.ci/) continuous integration
+  (CI) pipeline and task.
+- `spec/` contains the RSpec files for test driven development (TDD).
+  To run the tests:
+```bash
+DOMAIN=sslip.io rspec spec/
+```
+- `conf/sslip.io+nono.io.yml` contains the
+  [PowerDNS](https://www.powerdns.com/)'s [pipe
+  backend](https://doc.powerdns.com/md/authoritative/backend-pipe/)'s
+  configuration in YAML format for use with [BOSH](https://bosh.io). The
+  `pdns_pipe` key is the pipe backend script, and `pdns_pipe_conf` is its
+  configuration file.

conf/sslip.io+nono.io.yml

@@ -0,0 +1,261 @@
+pdns_named_conf: |
+  zone "nono.com" {
+    type slave;
+      file "/var/vcap/jobs/pdns/etc/nono.com";
+      masters { 78.46.204.247; };
+  };
+  zone "nono.io" {
+    type slave;
+      file "/var/vcap/jobs/pdns/etc/nono.io";
+      masters { 78.46.204.247; };
+  };
+pdns_conf: |
+  launch=bind:first,pipe:second
+  slave=yes
+  bind-first-config=/var/vcap/jobs/pdns/etc/named.conf
+  pipe-second-command=/var/vcap/jobs/pdns/bin/pipe /var/vcap/jobs/pdns/etc/pipe.conf
+pdns_pipe: |
+  #!/usr/bin/env bash
+  set -e
+  shopt -s nocasematch
+
+  #
+  # Configuration
+  #
+  XIP_DOMAIN="xip.test"
+  XIP_ROOT_ADDRESSES=( "127.0.0.1" )
+  XIP_NS_ADDRESSES=( "127.0.0.1" )
+  XIP_MX_RECORDS=( )
+  XIP_TIMESTAMP="0"
+  XIP_TTL=300
+
+  if [ -a "$1" ]; then
+    source "$1"
+  fi
+
+
+  #
+  # Protocol helpers
+  #
+  read_cmd() {
+    local IFS=$'\t'
+    local i=0
+    local arg
+
+    read -ra CMD
+    for arg; do
+      eval "$arg=\"\${CMD[$i]}\""
+      let i=i+1
+    done
+  }
+
+  send_cmd() {
+    local IFS=$'\t'
+    printf "%s\n" "$*"
+  }
+
+  fail() {
+    send_cmd "FAIL"
+    log "Exiting"
+    exit 1
+  }
+
+  read_helo() {
+    read_cmd HELO VERSION
+    [ "$HELO" = "HELO" ] && [ "$VERSION" = "1" ]
+  }
+
+  read_query() {
+    read_cmd TYPE QNAME QCLASS QTYPE ID IP
+  }
+
+  send_answer() {
+    local type="$1"
+    shift
+    send_cmd "DATA" "$QNAME" "$QCLASS" "$type" "$XIP_TTL" "$ID" "$@"
+  }
+
+  log() {
+    printf "[xip-pdns:$$] %s\n" "$@" >&2
+  }
+
+
+  #
+  # xip.io domain helpers
+  #
+  XIP_DOMAIN_PATTERN="(^|\.)${XIP_DOMAIN//./\.}\$"
+  NS_SUBDOMAIN_PATTERN="^ns-([0-9]+)\$"
+  IP_SUBDOMAIN_PATTERN="(^|\.)(((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))\$"
+  DASHED_IP_SUBDOMAIN_PATTERN="(^|-|\.)(((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)-){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))\$"
+  BASE36_SUBDOMAIN_PATTERN="(^|\.)([a-z0-9]{1,7})\$"
+
+  qtype_is() {
+    [ "$QTYPE" = "$1" ] || [ "$QTYPE" = "ANY" ]
+  }
+
+  qname_matches_domain() {
+    [[ "$QNAME" =~ $XIP_DOMAIN_PATTERN ]]
+  }
+
+  qname_is_root_domain() {
+    [ "$QNAME" = "$XIP_DOMAIN" ]
+  }
+
+  extract_subdomain_from_qname() {
+    SUBDOMAIN="${QNAME:0:${#QNAME}-${#XIP_DOMAIN}}"
+    SUBDOMAIN="${SUBDOMAIN%.}"
+  }
+
+  subdomain_is_ns() {
+    [[ "$SUBDOMAIN" =~ $NS_SUBDOMAIN_PATTERN ]]
+  }
+
+  subdomain_is_ip() {
+    [[ "$SUBDOMAIN" =~ $IP_SUBDOMAIN_PATTERN ]]
+  }
+
+  subdomain_is_dashed_ip() {
+    [[ "$SUBDOMAIN" =~ $DASHED_IP_SUBDOMAIN_PATTERN ]]
+  }
+
+  subdomain_is_base36() {
+    [[ "$SUBDOMAIN" =~ $BASE36_SUBDOMAIN_PATTERN ]]
+  }
+
+  resolve_ns_subdomain() {
+    local index="${SUBDOMAIN:3}"
+    echo "${XIP_NS_ADDRESSES[$index-1]}"
+  }
+
+  resolve_ip_subdomain() {
+    [[ "$SUBDOMAIN" =~ $IP_SUBDOMAIN_PATTERN ]] || true
+    echo "${BASH_REMATCH[2]}"
+  }
+
+  resolve_dashed_ip_subdomain() {
+    [[ "$SUBDOMAIN" =~ $DASHED_IP_SUBDOMAIN_PATTERN ]] || true
+    echo "${BASH_REMATCH[2]//-/.}"
+  }
+
+  resolve_base36_subdomain() {
+    [[ "$SUBDOMAIN" =~ $BASE36_SUBDOMAIN_PATTERN ]] || true
+    local ip=$(( 36#${BASH_REMATCH[2]} ))
+    printf "%d.%d.%d.%d" $(( ip&0xFF )) $(( (ip>>8)&0xFF )) $(( (ip>>16)&0xFF )) $(( (ip>>24)&0xFF ))
+  }
+
+  answer_soa_query() {
+    send_answer "SOA" "admin.$XIP_DOMAIN ns-1.$XIP_DOMAIN $XIP_TIMESTAMP $XIP_TTL $XIP_TTL $XIP_TTL $XIP_TTL"
+  }
+
+  answer_ns_query() {
+    local i=1
+    local ns_address
+    for ns in "${XIP_NS[@]}"; do
+      send_answer "NS" "$ns"
+    done
+  }
+
+  answer_root_a_query() {
+    local address
+    for address in "${XIP_ROOT_ADDRESSES[@]}"; do
+      send_answer "A" "$address"
+    done
+  }
+
+  answer_mx_query() {
+    set -- "${XIP_MX_RECORDS[@]}"
+    while [ $# -gt 1 ]; do
+      send_answer "MX" "$1	$2"
+    shift 2
+    done
+  }
+
+  answer_subdomain_a_query_for() {
+    local type="$1"
+    local address="$(resolve_${type}_subdomain)"
+    if [ -n "$address" ]; then
+      send_answer "A" "$address"
+    fi
+  }
+
+
+  #
+  # PowerDNS pipe backend implementation
+  #
+  trap fail err
+  read_helo
+  send_cmd "OK" "xip.io PowerDNS pipe backend (protocol version 1)"
+
+  while read_query; do
+    log "Query: type=$TYPE qname=$QNAME qclass=$QCLASS qtype=$QTYPE id=$ID ip=$IP"
+
+    if qname_matches_domain; then
+      if qname_is_root_domain; then
+        if qtype_is "SOA"; then
+          answer_soa_query
+        fi
+
+        if qtype_is "NS"; then
+          answer_ns_query
+        fi
+
+        if qtype_is "A"; then
+          answer_root_a_query
+        fi
+
+        if qtype_is "MX"; then
+          answer_mx_query
+        fi
+
+      elif qtype_is "A"; then
+        extract_subdomain_from_qname
+
+        if subdomain_is_ns; then
+          answer_subdomain_a_query_for ns
+
+        elif subdomain_is_dashed_ip; then
+          answer_subdomain_a_query_for dashed_ip
+
+        elif subdomain_is_ip; then
+          answer_subdomain_a_query_for ip
+
+        elif subdomain_is_base36; then
+          answer_subdomain_a_query_for base36
+        fi
+      fi
+    fi
+
+    send_cmd "END"
+  done
+pdns_pipe_conf: |
+  # Increment this timestamp when the contents of the file change.
+  XIP_TIMESTAMP="2016090200"
+
+  # The top-level domain for which the name server is authoritative.
+  # CHANGEME: change "sslip.io" to your domain
+  XIP_DOMAIN="sslip.io"
+
+  # The public IP addresses (e.g. for the web site) of the top-level domain.
+  # `A` queries for the top-level domain will return this list of addresses.
+  # CHANGEME: change this to your domain's webserver's address
+  XIP_ROOT_ADDRESSES=( "52.0.56.137" )
+
+  # The public IP addresses on which this xip-pdns server will run.
+  # `NS` queries for the top-level domain will return this list of addresses.
+  # Each entry maps to a 1-based subdomain of the format `ns-1`, `ns-2`, etc.
+  # `A` queries for these subdomains map to the corresponding addresses here.
+  # CHANGEME: change this to match your NS records; one of these IP addresses
+  # should match the jobs(xip).networks.static_ips listed above
+  XIP_NS_ADDRESSES=( "52.0.56.137" "78.47.249.19" )
+  XIP_NS=( "ns-aws.nono.io" "ns-gce.nono.io" "ns-he.nono.io" )
+
+  # These are the MX records for your domain.  IF YOU'RE NOT SURE,
+  # don't set it at at all (comment it out)--it defaults to no
+  # MX records.
+  XIP_MX_RECORDS=(
+    "10"  "mx.zoho.com"
+    "20"  "mx2.zoho.com"
+  )
+
+  # How long responses should be cached, in seconds.
+  XIP_TTL=300