fix(#3817): send servername for SNI on TLS (#3821) [backport]

lib/interceptor/dns.js

@@ -0,0 +1,375 @@
+'use strict'
+const { isIP } = require('node:net')
+const { lookup } = require('node:dns')
+const DecoratorHandler = require('../handler/decorator-handler')
+const { InvalidArgumentError, InformationalError } = require('../core/errors')
+const maxInt = Math.pow(2, 31) - 1
+
+class DNSInstance {
+  #maxTTL = 0
+  #maxItems = 0
+  #records = new Map()
+  dualStack = true
+  affinity = null
+  lookup = null
+  pick = null
+
+  constructor (opts) {
+    this.#maxTTL = opts.maxTTL
+    this.#maxItems = opts.maxItems
+    this.dualStack = opts.dualStack
+    this.affinity = opts.affinity
+    this.lookup = opts.lookup ?? this.#defaultLookup
+    this.pick = opts.pick ?? this.#defaultPick
+  }
+
+  get full () {
+    return this.#records.size === this.#maxItems
+  }
+
+  runLookup (origin, opts, cb) {
+    const ips = this.#records.get(origin.hostname)
+
+    // If full, we just return the origin
+    if (ips == null && this.full) {
+      cb(null, origin.origin)
+      return
+    }
+
+    const newOpts = {
+      affinity: this.affinity,
+      dualStack: this.dualStack,
+      lookup: this.lookup,
+      pick: this.pick,
+      ...opts.dns,
+      maxTTL: this.#maxTTL,
+      maxItems: this.#maxItems
+    }
+
+    // If no IPs we lookup
+    if (ips == null) {
+      this.lookup(origin, newOpts, (err, addresses) => {
+        if (err || addresses == null || addresses.length === 0) {
+          cb(err ?? new InformationalError('No DNS entries found'))
+          return
+        }
+
+        this.setRecords(origin, addresses)
+        const records = this.#records.get(origin.hostname)
+
+        const ip = this.pick(
+          origin,
+          records,
+          newOpts.affinity
+        )
+
+        let port
+        if (typeof ip.port === 'number') {
+          port = `:${ip.port}`
+        } else if (origin.port !== '') {
+          port = `:${origin.port}`
+        } else {
+          port = ''
+        }
+
+        cb(
+          null,
+          `${origin.protocol}//${
+            ip.family === 6 ? `[${ip.address}]` : ip.address
+          }${port}`
+        )
+      })
+    } else {
+      // If there's IPs we pick
+      const ip = this.pick(
+        origin,
+        ips,
+        newOpts.affinity
+      )
+
+      // If no IPs we lookup - deleting old records
+      if (ip == null) {
+        this.#records.delete(origin.hostname)
+        this.runLookup(origin, opts, cb)
+        return
+      }
+
+      let port
+      if (typeof ip.port === 'number') {
+        port = `:${ip.port}`
+      } else if (origin.port !== '') {
+        port = `:${origin.port}`
+      } else {
+        port = ''
+      }
+
+      cb(
+        null,
+        `${origin.protocol}//${
+          ip.family === 6 ? `[${ip.address}]` : ip.address
+        }${port}`
+      )
+    }
+  }
+
+  #defaultLookup (origin, opts, cb) {
+    lookup(
+      origin.hostname,
+      {
+        all: true,
+        family: this.dualStack === false ? this.affinity : 0,
+        order: 'ipv4first'
+      },
+      (err, addresses) => {
+        if (err) {
+          return cb(err)
+        }
+
+        const results = new Map()
+
+        for (const addr of addresses) {
+          // On linux we found duplicates, we attempt to remove them with
+          // the latest record
+          results.set(`${addr.address}:${addr.family}`, addr)
+        }
+
+        cb(null, results.values())
+      }
+    )
+  }
+
+  #defaultPick (origin, hostnameRecords, affinity) {
+    let ip = null
+    const { records, offset } = hostnameRecords
+
+    let family
+    if (this.dualStack) {
+      if (affinity == null) {
+        // Balance between ip families
+        if (offset == null || offset === maxInt) {
+          hostnameRecords.offset = 0
+          affinity = 4
+        } else {
+          hostnameRecords.offset++
+          affinity = (hostnameRecords.offset & 1) === 1 ? 6 : 4
+        }
+      }
+
+      if (records[affinity] != null && records[affinity].ips.length > 0) {
+        family = records[affinity]
+      } else {
+        family = records[affinity === 4 ? 6 : 4]
+      }
+    } else {
+      family = records[affinity]
+    }
+
+    // If no IPs we return null
+    if (family == null || family.ips.length === 0) {
+      return ip
+    }
+
+    if (family.offset == null || family.offset === maxInt) {
+      family.offset = 0
+    } else {
+      family.offset++
+    }
+
+    const position = family.offset % family.ips.length
+    ip = family.ips[position] ?? null
+
+    if (ip == null) {
+      return ip
+    }
+
+    if (Date.now() - ip.timestamp > ip.ttl) { // record TTL is already in ms
+      // We delete expired records
+      // It is possible that they have different TTL, so we manage them individually
+      family.ips.splice(position, 1)
+      return this.pick(origin, hostnameRecords, affinity)
+    }
+
+    return ip
+  }
+
+  setRecords (origin, addresses) {
+    const timestamp = Date.now()
+    const records = { records: { 4: null, 6: null } }
+    for (const record of addresses) {
+      record.timestamp = timestamp
+      if (typeof record.ttl === 'number') {
+        // The record TTL is expected to be in ms
+        record.ttl = Math.min(record.ttl, this.#maxTTL)
+      } else {
+        record.ttl = this.#maxTTL
+      }
+
+      const familyRecords = records.records[record.family] ?? { ips: [] }
+
+      familyRecords.ips.push(record)
+      records.records[record.family] = familyRecords
+    }
+
+    this.#records.set(origin.hostname, records)
+  }
+
+  getHandler (meta, opts) {
+    return new DNSDispatchHandler(this, meta, opts)
+  }
+}
+
+class DNSDispatchHandler extends DecoratorHandler {
+  #state = null
+  #opts = null
+  #dispatch = null
+  #handler = null
+  #origin = null
+
+  constructor (state, { origin, handler, dispatch }, opts) {
+    super(handler)
+    this.#origin = origin
+    this.#handler = handler
+    this.#opts = { ...opts }
+    this.#state = state
+    this.#dispatch = dispatch
+  }
+
+  onError (err) {
+    switch (err.code) {
+      case 'ETIMEDOUT':
+      case 'ECONNREFUSED': {
+        if (this.#state.dualStack) {
+          // We delete the record and retry
+          this.#state.runLookup(this.#origin, this.#opts, (err, newOrigin) => {
+            if (err) {
+              return this.#handler.onError(err)
+            }
+
+            const dispatchOpts = {
+              ...this.#opts,
+              origin: newOrigin
+            }
+
+            this.#dispatch(dispatchOpts, this)
+          })
+
+          // if dual-stack disabled, we error out
+          return
+        }
+
+        this.#handler.onError(err)
+        return
+      }
+      case 'ENOTFOUND':
+        this.#state.deleteRecord(this.#origin)
+      // eslint-disable-next-line no-fallthrough
+      default:
+        this.#handler.onError(err)
+        break
+    }
+  }
+}
+
+module.exports = interceptorOpts => {
+  if (
+    interceptorOpts?.maxTTL != null &&
+    (typeof interceptorOpts?.maxTTL !== 'number' || interceptorOpts?.maxTTL < 0)
+  ) {
+    throw new InvalidArgumentError('Invalid maxTTL. Must be a positive number')
+  }
+
+  if (
+    interceptorOpts?.maxItems != null &&
+    (typeof interceptorOpts?.maxItems !== 'number' ||
+      interceptorOpts?.maxItems < 1)
+  ) {
+    throw new InvalidArgumentError(
+      'Invalid maxItems. Must be a positive number and greater than zero'
+    )
+  }
+
+  if (
+    interceptorOpts?.affinity != null &&
+    interceptorOpts?.affinity !== 4 &&
+    interceptorOpts?.affinity !== 6
+  ) {
+    throw new InvalidArgumentError('Invalid affinity. Must be either 4 or 6')
+  }
+
+  if (
+    interceptorOpts?.dualStack != null &&
+    typeof interceptorOpts?.dualStack !== 'boolean'
+  ) {
+    throw new InvalidArgumentError('Invalid dualStack. Must be a boolean')
+  }
+
+  if (
+    interceptorOpts?.lookup != null &&
+    typeof interceptorOpts?.lookup !== 'function'
+  ) {
+    throw new InvalidArgumentError('Invalid lookup. Must be a function')
+  }
+
+  if (
+    interceptorOpts?.pick != null &&
+    typeof interceptorOpts?.pick !== 'function'
+  ) {
+    throw new InvalidArgumentError('Invalid pick. Must be a function')
+  }
+
+  const dualStack = interceptorOpts?.dualStack ?? true
+  let affinity
+  if (dualStack) {
+    affinity = interceptorOpts?.affinity ?? null
+  } else {
+    affinity = interceptorOpts?.affinity ?? 4
+  }
+
+  const opts = {
+    maxTTL: interceptorOpts?.maxTTL ?? 10e3, // Expressed in ms
+    lookup: interceptorOpts?.lookup ?? null,
+    pick: interceptorOpts?.pick ?? null,
+    dualStack,
+    affinity,
+    maxItems: interceptorOpts?.maxItems ?? Infinity
+  }
+
+  const instance = new DNSInstance(opts)
+
+  return dispatch => {
+    return function dnsInterceptor (origDispatchOpts, handler) {
+      const origin =
+        origDispatchOpts.origin.constructor === URL
+          ? origDispatchOpts.origin
+          : new URL(origDispatchOpts.origin)
+
+      if (isIP(origin.hostname) !== 0) {
+        return dispatch(origDispatchOpts, handler)
+      }
+
+      instance.runLookup(origin, origDispatchOpts, (err, newOrigin) => {
+        if (err) {
+          return handler.onError(err)
+        }
+
+        let dispatchOpts = null
+        dispatchOpts = {
+          ...origDispatchOpts,
+          servername: origin.hostname, // For SNI on TLS
+          origin: newOrigin,
+          headers: {
+            host: origin.hostname,
+            ...origDispatchOpts.headers
+          }
+        }
+
+        dispatch(
+          dispatchOpts,
+          instance.getHandler({ origin, dispatch, handler }, origDispatchOpts)
+        )
+      })
+
+      return true
+    }
+  }
+}