1 files changed, 92 insertions, 0 deletions
diff --git a/ddns-update b/ddns-update
new file mode 100755
index 0000000..7bfabf9
--- /dev/null
+++ b/ddns-update
@@ -0,0 +1,92 @@
+#!/bin/bash
+
+# update dns records of
+# pool.mirror.archlinux32.org = CNAME pool32.ddns.eckner.net
+
+# either called with 1 argument (the ip to check and add) or without
+# arguments (all known mirrors will be checked in parallel)
+
+set -e
+
+if [ $# -eq 1 ]; then
+  if [ "${1%.*}" != "$1" ]; then
+    ipver='A'
+    lft=''
+    rt=''
+  elif [ "${1%:*}" != "$1" ]; then
+    ipver='AAAA'
+    lft='['
+    rt=']'
+  else
+    exit
+  fi
+
+  if [ "$(curl \
+    -w '%{http_code}' \
+    -L \
+    -o /dev/null \
+    --connect-timeout 10 \
+    --resolve "pool.mirror.archlinux32.org:80:${lft}$1${rt}" \
+    -s 'http://pool.mirror.archlinux32.org/i686/')" != '200' ]; then
+    exit
+  fi
+
+  printf '%s %s\n' "${ipver}" "$1"
+  exit
+fi
+
+{
+  for type in 'A' 'AAAA'; do
+    printf '%s\n' \
+      'zone ddns.eckner.net.' \
+      'prereq yxrrset pool32.ddns.eckner.net IN '"${type}" \
+      'update delete pool32.ddns.eckner.net IN '"${type}" \
+      'send'
+  done
+  printf 'zone ddns.eckner.net.\n'
+  curl -s 'https://packages.archlinux32.org/mirrors/status.php?tsv' | \
+    {
+      read -r headers
+      url_column=$(
+        printf '%s\n' "${headers}" | \
+          tr '\t' '\n' | \
+          grep -nxF 'url' | \
+          cut -d: -f1
+      )
+      recently_active_column=$(
+        printf '%s\n' "${headers}" | \
+          tr '\t' '\n' | \
+          grep -nxF 'recently_active' | \
+          cut -d: -f1
+      )
+      awk '{
+        print $'"${recently_active_column}"' "\t" $'"${url_column}"'
+      }'
+    } | \
+    sed -n '
+      s/^1\t//
+      T
+      \|//mirror\.archlinux32\.org/|d
+      s|[^:]\+://||
+      T
+      s|/.*$||
+      p
+    ' | \
+    sort -u | \
+    parallel -j0 getent ahosts | \
+    sed -n '
+      s/\s\+STREAM\(\s.*\)\?$//
+      T
+      p
+    ' | \
+    sort -u | \
+    parallel -j0 "$0" | \
+    sed '
+      s/^/update add pool32.ddns.eckner.net. 3600 IN /
+    '
+  printf '%s\n' \
+    'send'
+} | \
+  nsupdate -l
+
+exit 0