dns: add hardcoded icann fallback.

lib/dns/icann-browser.js

@@ -0,0 +1,69 @@
+'use strict';
+
+const assert = require('assert');
+const tld = require('./tld.json');
+
+/**
+ * ICANN Root Zone
+ */
+
+class ICANN {
+  constructor(data) {
+    this.data = data;
+  }
+
+  has(name) {
+    assert(typeof name === 'string');
+
+    name = trimFQDN(name);
+
+    if (name.length === 0 || name.length > 63)
+      return false;
+
+    name = name.toLowerCase();
+
+    const data = this.data[name];
+
+    if (!data)
+      return false;
+
+    return typeof data === 'string';
+  }
+
+  get(name) {
+    assert(typeof name === 'string');
+
+    name = trimFQDN(name);
+
+    if (name.length === 0 || name.length > 63)
+      return null;
+
+    name = name.toLowerCase();
+
+    const data = this.data[name];
+
+    if (!data)
+      return false;
+
+    if (typeof data !== 'string')
+      return null;
+
+    return Buffer.from(data, 'base64');
+  }
+}
+
+/*
+ * Helpers
+ */
+
+function trimFQDN(name) {
+  if (name.length > 0 && name[name.length - 1] === '.')
+    name = name.slice(0, -1);
+  return name;
+}
+
+/*
+ * Expose
+ */
+
+module.exports = new ICANN(tld);

lib/dns/icann.js

@@ -0,0 +1,139 @@
+'use strict';
+
+const assert = require('assert');
+const Path = require('path');
+const fs = require('bfile');
+
+/*
+ * Constants
+ */
+
+const FILE = Path.resolve(__dirname, 'tld.db');
+const DATA = fs.readFileSync(FILE);
+
+/**
+ * ICANN Root Zone
+ */
+
+class ICANN {
+  constructor(data) {
+    this.data = data;
+    this.size = readU32(data, 0);
+    this.nameSize = data[4];
+  }
+
+  _compare(b, off) {
+    const a = this.data;
+    const alen = a[off - 1];
+    const blen = b.length;
+    const len = alen < blen ? alen : blen;
+
+    for (let i = 0; i < len; i++) {
+      const x = a[off + i];
+      const y = b[i];
+
+      if (x < y)
+        return -1;
+
+      if (x > y)
+        return 1;
+    }
+
+    if (alen < blen)
+      return -1;
+
+    if (alen > blen)
+      return 1;
+
+    return 0;
+  }
+
+  _find(key) {
+    let start = 0;
+    let end = this.size - 1;
+
+    while (start <= end) {
+      const index = (start + end) >>> 1;
+      const pos = 5 + index * (1 + this.nameSize + 4);
+      const cmp = this._compare(key, pos + 1);
+
+      if (cmp === 0)
+        return readU32(this.data, pos + 1 + this.nameSize);
+
+      if (cmp < 0)
+        start = index + 1;
+      else
+        end = index - 1;
+    }
+
+    return -1;
+  }
+
+  _data(pos) {
+    const len = readU16(this.data, pos);
+    return this.data.slice(pos + 2, pos + 2 + len);
+  }
+
+  _has(key) {
+    return this._find(key) !== -1;
+  }
+
+  _get(key) {
+    const pos = this._find(key);
+
+    if (pos === -1)
+      return null;
+
+    return this._data(pos);
+  }
+
+  has(name) {
+    assert(typeof name === 'string');
+
+    name = trimFQDN(name);
+
+    if (name.length === 0 || name.length > 63)
+      return false;
+
+    return this._has(toKey(name));
+  }
+
+  get(name) {
+    assert(typeof name === 'string');
+
+    name = trimFQDN(name);
+
+    if (name.length === 0 || name.length > 63)
+      return null;
+
+    return this._get(toKey(name));
+  }
+}
+
+/*
+ * Helpers
+ */
+
+function readU16(data, off) {
+  return data.readUInt16LE(off);
+}
+
+function readU32(data, off) {
+  return data.readUInt32LE(off);
+}
+
+function trimFQDN(name) {
+  if (name.length > 0 && name[name.length - 1] === '.')
+    name = name.slice(0, -1);
+  return name;
+}
+
+function toKey(name) {
+  return Buffer.from(name.toLowerCase(), 'ascii');
+}
+
+/*
+ * Expose
+ */
+
+module.exports = new ICANN(DATA);

package.json

@@ -91,6 +91,7 @@
   },
   "browser": {
     "./lib/covenants/reserved": "./lib/covenants/reserved-browser.js",
+    "./lib/dns/icann": "./lib/dns/icann-browser.js",
     "./lib/hd/nfkd": "./lib/hd/nfkd-compat.js",
     "./lib/hd/wordlist": "./lib/hd/wordlist-browser.js",
     "./lib/workers/child": "./lib/workers/child-browser.js",