1import { getMyCfExtIp } from './cfIpF.mts'
2import { dnsLookup } from './dnsF.mts'
3import { getLanCache, setLanCache } from './isOnSameLanCacheF.mts'
4import * as os from 'os'
5
6const isIpInLocalSubnet = (targetIp: string) => {
7  const ifaces = os.networkInterfaces()
8  const toInt = (ip: string) => ip.split('.').reduce((acc, oct) => (acc << 8) + parseInt(oct), 0) >>> 0
9  const targetInt = toInt(targetIp)
10  for (const [name, addrs] of Object.entries(ifaces)) {
11    if (!addrs || name === 'lo' || name === 'lo0') continue
12    for (const a of addrs) {
13      if (a.family !== 'IPv4' || a.internal) continue
14      if ((toInt(a.address) & toInt(a.netmask)) === (targetInt & toInt(a.netmask))) return true
15    }
16  }
17  return false
18}
19
20export const isOnSameLan = async ({cluster_name, nodeIpsExtHost, clusterVip}: {
21  cluster_name: string
22  nodeIpsExtHost?: string
23  clusterVip?: string
24}) => {
25  if (getLanCache(cluster_name) !== undefined) return getLanCache(cluster_name)
26  if (!nodeIpsExtHost || cluster_name === 'minik') return false
27
28  // same-site clusters share a WAN egress IP (ext-ip check below false-positives for them),
29  // so clusterVip subnet membership is a required condition, not just a fast-path negative
30  if (!clusterVip || !isIpInLocalSubnet(clusterVip)) {
31    setLanCache(cluster_name, false)
32    return false
33  }
34
35  try {
36    const myExtIp = await getMyCfExtIp()
37    const {address: clusterExtIp} = await dnsLookup(nodeIpsExtHost, {family: 4})
38    const inLan = myExtIp === clusterExtIp
39    setLanCache(cluster_name, inLan)
40    return inLan
41  } catch (err: unknown) {
42    console.warn('isOnSameLan detection failed, defaulting to external:', (err as Error)?.message || err)
43    setLanCache(cluster_name, false)
44    return false
45  }
46}
47
48let tailnetCached: boolean | undefined
49export const isOnTailnet = () => {
50  if (tailnetCached !== undefined) return tailnetCached
51  const ifaces = os.networkInterfaces()
52  for (const addrs of Object.values(ifaces)) {
53    if (!addrs) continue
54    for (const a of addrs) {
55      if (a.family !== 'IPv4' || a.internal) continue
56      const [first, second] = a.address.split('.').map(Number)
57      if (first === 100 && second >= 64 && second <= 127) return (tailnetCached = true)
58    }
59  }
60  return (tailnetCached = false)
61}
62