chore: prepare GoodBuddy 0.8.2

src/shared/intranet-hostname.ts

@@ -0,0 +1,95 @@
+const INTRANET_HOST_SUFFIXES = [
+  '.home',
+  '.internal',
+  '.intranet',
+  '.lan',
+  '.local',
+  '.localdomain',
+  '.localhost'
+] as const
+
+const BLOCKED_HOSTNAMES = new Set([
+  '100.100.100.200',
+  'fd00:ec2::254',
+  'instance-data',
+  'instance-data.ec2.internal',
+  'metadata',
+  'metadata.aws.internal',
+  'metadata.google.internal'
+])
+
+function normalizeHostname(hostname: string): string {
+  const normalized = hostname.trim().toLowerCase().replace(/\.$/u, '')
+  return normalized.startsWith('[') && normalized.endsWith(']')
+    ? normalized.slice(1, -1)
+    : normalized
+}
+
+function parseIpv4(hostname: string): readonly number[] | undefined {
+  const octets = hostname.split('.')
+  if (
+    octets.length !== 4 ||
+    octets.some(
+      (octet) =>
+        !/^(?:0|[1-9]\d{0,2})$/u.test(octet) ||
+        Number(octet) > 255
+    )
+  ) {
+    return undefined
+  }
+  return octets.map(Number)
+}
+
+function isIntranetIpv4(hostname: string): boolean {
+  const octets = parseIpv4(hostname)
+  if (!octets) {
+    return false
+  }
+  const [first = -1, second = -1] = octets
+  return (
+    first === 10 ||
+    first === 127 ||
+    (first === 100 && second >= 64 && second <= 127) ||
+    (first === 172 && second >= 16 && second <= 31) ||
+    (first === 192 && second === 168)
+  )
+}
+
+function isIntranetIpv6(hostname: string): boolean {
+  const withoutZone = hostname.split('%', 1)[0] ?? ''
+  return (
+    withoutZone === '::1' ||
+    /^f[cd][0-9a-f]{2}(?::|$)/u.test(withoutZone)
+  )
+}
+
+export function isLoopbackHostname(hostname: string): boolean {
+  const normalized = normalizeHostname(hostname)
+  const ipv4 = parseIpv4(normalized)
+  return (
+    normalized === 'localhost' ||
+    normalized === '::1' ||
+    ipv4?.[0] === 127
+  )
+}
+
+export function isIntranetHostname(hostname: string): boolean {
+  const normalized = normalizeHostname(hostname)
+  if (!normalized || BLOCKED_HOSTNAMES.has(normalized)) {
+    return false
+  }
+  if (parseIpv4(normalized)) {
+    return isIntranetIpv4(normalized)
+  }
+  if (normalized.includes(':')) {
+    return isIntranetIpv6(normalized)
+  }
+  return (
+    isLoopbackHostname(normalized) ||
+    !normalized.includes('.') ||
+    INTRANET_HOST_SUFFIXES.some(
+      (suffix) =>
+        normalized === suffix.slice(1) || normalized.endsWith(suffix)
+    )
+  )
+}