Wire Newbook credentials to settings service

backend/src/ip-check.js

@@ -0,0 +1,80 @@
+import dns from 'dns/promises'
+
+const raw = (process.env.OFFICE_IP_CHECK || 'disabled').trim()
+const matchers = raw.split(',').map(s => s.trim()).filter(Boolean)
+
+const TTL = 5 * 60 * 1000
+const cache = new Map()
+
+const PUBLIC_IP_URLS = [
+  'https://api.ipify.org',
+  'https://ifconfig.co/ip',
+  'https://icanhazip.com',
+]
+
+function normalizeIP(ip) {
+  return ip?.startsWith('::ffff:') ? ip.slice(7) : ip
+}
+
+function isIPv4(s) {
+  return /^\d{1,3}(\.\d{1,3}){3}$/.test(s)
+}
+
+function ipInCidr(ip, cidr) {
+  const [range, bits] = cidr.split('/')
+  if (!isIPv4(ip) || !isIPv4(range)) return false
+  const mask = ~(2 ** (32 - parseInt(bits)) - 1) >>> 0
+  const toInt = s => s.split('.').reduce((a, o) => (a << 8) + parseInt(o), 0) >>> 0
+  return (toInt(ip) & mask) === (toInt(range) & mask)
+}
+
+async function fetchPublicIP() {
+  for (const url of PUBLIC_IP_URLS) {
+    try {
+      const ctrl = new AbortController()
+      const timer = setTimeout(() => ctrl.abort(), 4000)
+      const res = await fetch(url, { signal: ctrl.signal })
+      clearTimeout(timer)
+      if (!res.ok) continue
+      const ip = (await res.text()).trim()
+      if (isIPv4(ip)) return ip
+    } catch {
+      // try next
+    }
+  }
+  return null
+}
+
+async function resolveDynamic(key, resolver) {
+  const hit = cache.get(key)
+  if (hit && Date.now() < hit.expiry) return hit.ip
+  const ip = await resolver()
+  if (ip) {
+    cache.set(key, { ip, expiry: Date.now() + TTL })
+    return ip
+  }
+  return hit ? hit.ip : null
+}
+
+export async function isOnsite(requestIP) {
+  if (matchers.length === 0 || matchers.includes('disabled')) return true
+  const ip = normalizeIP(requestIP)
+  if (!ip) return false
+
+  for (const m of matchers) {
+    if (m === 'auto') {
+      const pub = await resolveDynamic('auto', fetchPublicIP)
+      if (pub && ip === pub) return true
+    } else if (m.includes('/')) {
+      if (ipInCidr(ip, m)) return true
+    } else if (/[a-zA-Z]/.test(m)) {
+      const resolved = await resolveDynamic(m, async () => {
+        try { return (await dns.resolve4(m))[0] } catch { return null }
+      })
+      if (resolved && ip === resolved) return true
+    } else {
+      if (ip === m) return true
+    }
+  }
+  return false
+}