q3rcon-proxy/pkg/udpproxy/validator.go

package udpproxy

import "bytes"

type validator struct {
	rconRequestHeader         []byte
	getstatusRequestHeader    []byte
	getinfoRequestHeader      []byte
	getchallengeRequestHeader []byte
	rconResponseHeader        []byte
	getstatusResponseHeader   []byte
	getinfoResponseHeader     []byte
	badRconIdentifier         []byte
}

func newValidator() validator {
	return validator{
		rconRequestHeader:         []byte("\xff\xff\xff\xffrcon"),
		getstatusRequestHeader:    []byte("\xff\xff\xff\xffgetstatus"),
		getinfoRequestHeader:      []byte("\xff\xff\xff\xffgetinfo"),
		getchallengeRequestHeader: []byte("\xff\xff\xff\xffgetchallenge"),
		rconResponseHeader:        []byte("\xff\xff\xff\xffprint\n"),
		getstatusResponseHeader:   []byte("\xff\xff\xff\xffstatusResponse\n"),
		getinfoResponseHeader:     []byte("\xff\xff\xff\xffinfoResponse\n"),
		badRconIdentifier:         []byte("Bad rcon"),
	}
}

func (v validator) compare(buf, c []byte) bool {
	return bytes.Equal(buf[:len(c)], c)
}

func (v validator) isRconRequestPacket(buf []byte) bool {
	return v.compare(buf, v.rconRequestHeader)
}

func (v validator) isQueryRequestPacket(buf []byte) bool {
	return v.compare(buf, v.getstatusRequestHeader) ||
		v.compare(buf, v.getinfoRequestHeader)
}

func (v validator) isValidRequestPacket(buf []byte) bool {
	return v.isRconRequestPacket(buf) || v.isQueryRequestPacket(buf)
}

func (v validator) isChallengeRequestPacket(buf []byte) bool {
	return v.compare(buf, v.getchallengeRequestHeader)
}

func (v validator) isRconResponsePacket(buf []byte) bool {
	return v.compare(buf, v.rconResponseHeader)
}

func (v validator) isQueryResponsePacket(buf []byte) bool {
	return v.compare(buf, v.getstatusResponseHeader) ||
		v.compare(buf, v.getinfoResponseHeader)
}

func (v validator) isValidResponsePacket(buf []byte) bool {
	return v.isRconResponsePacket(buf) || v.isQueryResponsePacket(buf)
}

func (v validator) isBadRconResponse(buf []byte) bool {
	return v.compare(buf[len(v.rconResponseHeader):], v.badRconIdentifier)
}