node-gamedig/protocols/gamespy3.js

import Core from './core.js'

export default class gamespy3 extends Core {
  constructor () {
    super()
    this.sessionId = 1
    this.encoding = 'latin1'
    this.byteorder = 'be'
    this.useOnlySingleSplit = false
    this.isJc2mp = false
  }

  async run (state) {
    const buffer = await this.sendPacket(9, false, false, false)
    const reader = this.reader(buffer)
    let challenge = parseInt(reader.string())
    this.logger.debug('Received challenge key: ' + challenge)
    if (challenge === 0) {
      // Some servers send us a 0 if they don't want a challenge key used
      // BF2 does this.
      challenge = null
    }

    let requestPayload
    if (this.isJc2mp) {
      // they completely alter the protocol. because why not.
      requestPayload = Buffer.from([0xff, 0xff, 0xff, 0x02])
    } else {
      requestPayload = Buffer.from([0xff, 0xff, 0xff, 0x01])
    }
    /** @type Buffer[] */
    const packets = await this.sendPacket(0, challenge, requestPayload, true)

    // iterate over the received packets
    // the first packet will start off with k/v pairs, followed with data fields
    // the following packets will only have data fields
    state.raw.playerTeamInfo = {}

    for (let iPacket = 0; iPacket < packets.length; iPacket++) {
      const packet = packets[iPacket]
      const reader = this.reader(packet)

      this.logger.debug('Parsing packet #' + iPacket)
      this.logger.debug(packet)

      // Parse raw server key/values

      if (iPacket === 0) {
        while (!reader.done()) {
          const key = reader.string()
          if (!key) break

          let value = reader.string()
          while (value.match(/^p[0-9]+$/)) {
            // fix a weird ut3 bug where some keys don't have values
            value = reader.string()
          }

          state.raw[key] = value
          this.logger.debug(key + ' = ' + value)
        }
      }

      // Parse player, team, item array state

      if (this.isJc2mp) {
        state.raw.numPlayers2 = reader.uint(2)
        while (!reader.done()) {
          const player = {}
          player.name = reader.string()
          player.steamid = reader.string()
          player.ping = reader.uint(2)
          state.players.push(player)
        }
      } else {
        while (!reader.done()) {
          if (reader.uint(1) <= 2) continue
          reader.skip(-1)
          const fieldId = reader.string()
          if (!fieldId) continue
          const fieldIdSplit = fieldId.split('_')
          const fieldName = fieldIdSplit[0]
          const itemType = fieldIdSplit.length > 1 ? fieldIdSplit[1] : 'no_'

          if (!(itemType in state.raw.playerTeamInfo)) {
            state.raw.playerTeamInfo[itemType] = []
          }
          const items = state.raw.playerTeamInfo[itemType]

          let offset = reader.uint(1)

          this.logger.debug(() => 'Parsing new field: itemType=' + itemType + ' fieldName=' + fieldName + ' startOffset=' + offset)

          while (!reader.done()) {
            const item = reader.string()
            if (!item) break

            while (items.length <= offset) { items.push({}) }
            items[offset][fieldName] = item
            this.logger.debug('* ' + item)
            offset++
          }
        }
      }
    }

    // Turn all that raw state into something useful

    if ('hostname' in state.raw) state.name = state.raw.hostname
    else if ('servername' in state.raw) state.name = state.raw.servername
    if ('mapname' in state.raw) state.map = state.raw.mapname
    if (state.raw.password === '1') state.password = true
    if ('maxplayers' in state.raw) state.maxplayers = parseInt(state.raw.maxplayers)
    if ('hostport' in state.raw) state.gamePort = parseInt(state.raw.hostport)

    if ('' in state.raw.playerTeamInfo) {
      for (const playerInfo of state.raw.playerTeamInfo['']) {
        const player = {}
        for (const from of Object.keys(playerInfo)) {
          let key = from
          let value = playerInfo[from]

          if (key === 'player') key = 'name'
          if (key === 'score' || key === 'ping' || key === 'team' || key === 'deaths' || key === 'pid') value = parseInt(value)
          player[key] = value
        }
        state.players.push(player)
      }
    }
  }

  async sendPacket (type, challenge, payload, assemble) {
    const challengeLength = challenge === null ? 0 : 4
    const payloadLength = payload ? payload.length : 0

    const b = Buffer.alloc(7 + challengeLength + payloadLength)
    b.writeUInt8(0xFE, 0)
    b.writeUInt8(0xFD, 1)
    b.writeUInt8(type, 2)
    b.writeUInt32BE(this.sessionId, 3)
    if (challengeLength) b.writeInt32BE(challenge, 7)
    if (payloadLength) payload.copy(b, 7 + challengeLength)

    let numPackets = 0
    const packets = {}
    return await this.udpSend(b, (buffer) => {
      const reader = this.reader(buffer)
      const iType = reader.uint(1)
      if (iType !== type) {
        this.logger.debug('Skipping packet, type mismatch')
        return
      }
      const iSessionId = reader.uint(4)
      if (iSessionId !== this.sessionId) {
        this.logger.debug('Skipping packet, session id mismatch')
        return
      }

      if (!assemble) {
        return reader.rest()
      }
      if (this.useOnlySingleSplit) {
        // has split headers, but they are worthless and only one packet is used
        reader.skip(11)
        return [reader.rest()]
      }

      reader.skip(9) // filler data -- usually set to 'splitnum\0'
      let id = reader.uint(1)
      const last = (id & 0x80)
      id = id & 0x7f
      if (last) numPackets = id + 1

      reader.skip(1) // "another 'packet number' byte, but isn't understood."

      packets[id] = reader.rest()
      if (this.debug) {
        this.logger.debug('Received packet #' + id + (last ? ' (last)' : ''))
      }

      if (!numPackets || Object.keys(packets).length !== numPackets) return

      // assemble the parts
      const list = []
      for (let i = 0; i < numPackets; i++) {
        if (!(i in packets)) {
          throw new Error('Missing packet #' + i)
        }
        list.push(packets[i])
      }
      return list
    })
  }
}