bgp-stayrtr/lib/server.go

package rtrlib

import (
	"bytes"
	"crypto/tls"
	"fmt"
	"golang.org/x/crypto/ssh"
	"io"
	"math/rand"
	"net"
	"sync"
	"time"
)

func GenerateSessionId() uint16 {
	var sessid uint16
	r := rand.New(rand.NewSource(time.Now().UTC().Unix()))
	sessid = uint16(r.Uint32())
	return sessid
}

type RTRServerEventHandler interface {
	ClientConnected(*Client)
	ClientDisconnected(*Client)
	HandlePDU(*Client, PDU)
}

type RTREventHandler interface {
	RequestCache(*Client)
	RequestNewVersion(*Client, uint16, uint32)
}

type ROAManager interface {
	GetCurrentSerial(uint16) (uint32, bool)
	GetSessionId(*Client) (uint16, error)
	GetCurrentROAs() ([]ROA, bool)
	GetROAsSerialDiff(uint32) ([]ROA, bool)
}

type DefaultRTREventHandler struct {
	roaManager ROAManager
	Log        Logger
}

func (e *DefaultRTREventHandler) SetROAManager(m ROAManager) {
	e.roaManager = m
}

func (e *DefaultRTREventHandler) RequestCache(c *Client) {
	if e.Log != nil {
		e.Log.Debugf("%v > Request Cache", c)
	}
	sessionId, _ := e.roaManager.GetSessionId(c)
	serial, valid := e.roaManager.GetCurrentSerial(sessionId)
	if !valid {
		c.SendNoDataError()
		if e.Log != nil {
			e.Log.Debugf("%v < No data", c)
		}
	} else {
		roas, exists := e.roaManager.GetCurrentROAs()
		if !exists {
			c.SendInternalError()
			if e.Log != nil {
				e.Log.Debugf("%v < Internal error requesting cache (does not exists)", c)
			}
		} else {
			c.SendROAs(sessionId, serial, roas)
			if e.Log != nil {
				e.Log.Debugf("%v < Sent ROAs (current serial %d, session: %d)", c, serial, sessionId)
			}
		}
	}
}

func (e *DefaultRTREventHandler) RequestNewVersion(c *Client, sessionId uint16, serialNumber uint32) {
	if e.Log != nil {
		e.Log.Debugf("%v > Request New Version", c)
	}
	serial, valid := e.roaManager.GetCurrentSerial(sessionId)
	if !valid {
		c.SendNoDataError()
		if e.Log != nil {
			e.Log.Debugf("%v < No data", c)
		}
	} else {
		roas, exists := e.roaManager.GetROAsSerialDiff(serialNumber)
		if !exists {
			c.SendCacheReset()
			if e.Log != nil {
				e.Log.Debugf("%v < Sent cache reset", c)
			}
		} else {
			c.SendROAs(sessionId, serial, roas)
			if e.Log != nil {
				e.Log.Debugf("%v < Sent ROAs (current serial %d, session from client: %d)", c, serial, sessionId)
			}
		}
	}
}

type Server struct {
	baseVersion uint8
	clientlock  *sync.RWMutex
	clients     []*Client
	sessId      uint16
	connected   int
	maxconn     int

	sshconfig *ssh.ServerConfig

	handler        RTRServerEventHandler
	simpleHandler  RTREventHandler
	enforceVersion bool

	roalock          *sync.RWMutex
	roaListDiff      [][]ROA
	roaMapSerial     map[uint32]int
	roaListSerial    []uint32
	roaCurrent       []ROA
	roaCurrentSerial uint32
	keepDiff         int
	manualserial     bool

	pduRefreshInterval uint32
	pduRetryInterval   uint32
	pduExpireInterval  uint32

	log        Logger
	logverbose bool
}

type ServerConfiguration struct {
	MaxConn         int
	ProtocolVersion uint8
	EnforceVersion  bool
	KeepDifference  int

	SessId int

	RefreshInterval uint32
	RetryInterval   uint32
	ExpireInterval  uint32

	Log        Logger
	LogVerbose bool
}

func NewServer(configuration ServerConfiguration, handler RTRServerEventHandler, simpleHandler RTREventHandler) *Server {
	var sessid uint16
	if configuration.SessId < 0 {
		sessid = GenerateSessionId()
	} else {
		sessid = uint16(configuration.SessId)
	}

	refreshInterval := uint32(3600)
	if configuration.RefreshInterval != 0 {
		refreshInterval = configuration.RefreshInterval
	}
	retryInterval := uint32(600)
	if configuration.RetryInterval != 0 {
		retryInterval = configuration.RetryInterval
	}
	expireInterval := uint32(7200)
	if configuration.ExpireInterval != 0 {
		expireInterval = configuration.ExpireInterval
	}

	return &Server{
		roalock:       &sync.RWMutex{},
		roaListDiff:   make([][]ROA, 0),
		roaMapSerial:  make(map[uint32]int),
		roaListSerial: make([]uint32, 0),
		roaCurrent:    make([]ROA, 0),
		keepDiff:      configuration.KeepDifference,

		clientlock:     &sync.RWMutex{},
		clients:        make([]*Client, 0),
		sessId:         sessid,
		maxconn:        configuration.MaxConn,
		baseVersion:    configuration.ProtocolVersion,
		enforceVersion: configuration.EnforceVersion,
		handler:        handler,
		simpleHandler:  simpleHandler,

		pduRefreshInterval: refreshInterval,
		pduRetryInterval:   retryInterval,
		pduExpireInterval:  expireInterval,

		log:        configuration.Log,
		logverbose: configuration.LogVerbose,
	}
}

func (roa ROA) HashKey() string {
	return fmt.Sprintf("%v-%v-%v", roa.Prefix.String(), roa.MaxLen, roa.ASN)
}

func ConvertROAListToMap(roas []ROA) map[string]ROA {
	roaMap := make(map[string]ROA, len(roas))
	for _, v := range roas {
		roaMap[v.HashKey()] = v
	}
	return roaMap
}

func ComputeDiff(newRoas []ROA, prevRoas []ROA) ([]ROA, []ROA, []ROA) {
	added := make([]ROA, 0)
	removed := make([]ROA, 0)
	unchanged := make([]ROA, 0)

	newRoasMap := ConvertROAListToMap(newRoas)
	prevRoasMap := ConvertROAListToMap(prevRoas)

	for _, roa := range newRoas {
		_, exists := prevRoasMap[roa.HashKey()]
		if !exists {
			rcopy := roa.Copy()
			rcopy.Flags = 1
			added = append(added, rcopy)
		}
	}
	for _, roa := range prevRoas {
		_, exists := newRoasMap[roa.HashKey()]
		if !exists {
			rcopy := roa.Copy()
			rcopy.Flags = 0
			removed = append(removed, rcopy)
		} else {
			rcopy := roa.Copy()
			unchanged = append(unchanged, rcopy)
		}
	}

	return added, removed, unchanged
}

func ApplyDiff(diff []ROA, prevRoas []ROA) []ROA {
	newroas := make([]ROA, 0)
	diffMap := ConvertROAListToMap(diff)
	prevRoasMap := ConvertROAListToMap(prevRoas)

	for _, roa := range prevRoas {
		_, exists := diffMap[roa.HashKey()]
		if !exists {
			rcopy := roa.Copy()
			newroas = append(newroas, rcopy)
		}
	}
	for _, roa := range diff {
		if roa.Flags == FLAG_ADDED {
			rcopy := roa.Copy()
			newroas = append(newroas, rcopy)
		} else if roa.Flags == FLAG_REMOVED {
			croa, exists := prevRoasMap[roa.HashKey()]
			if !exists {
				rcopy := roa.Copy()
				newroas = append(newroas, rcopy)
			} else {
				if croa.Flags == FLAG_REMOVED {
					rcopy := roa.Copy()
					newroas = append(newroas, rcopy)
				}
			}
		}

	}
	return newroas
}

func (s *Server) SetManualSerial(v bool) {
	s.manualserial = v
}

func (s *Server) GetSessionId(c *Client) (uint16, error) {
	return s.sessId, nil
}

func (s *Server) GetCurrentROAs() ([]ROA, bool) {
	s.roalock.RLock()
	roa := s.roaCurrent
	s.roalock.RUnlock()
	return roa, true
}

func (s *Server) GetROAsSerialDiff(serial uint32) ([]ROA, bool) {
	s.roalock.RLock()
	roa, ok := s.getROAsSerialDiff(serial)
	s.roalock.RUnlock()
	return roa, ok
}

func (s *Server) getROAsSerialDiff(serial uint32) ([]ROA, bool) {
	if serial == s.roaCurrentSerial {
		return []ROA{}, true
	}

	roa := make([]ROA, 0)
	index, ok := s.roaMapSerial[serial]
	if ok {
		roa = s.roaListDiff[index]
	}
	return roa, ok
}

func (s *Server) GetCurrentSerial(sessId uint16) (uint32, bool) {
	s.roalock.RLock()
	serial, valid := s.getCurrentSerial()
	s.roalock.RUnlock()
	return serial, valid
}

func (s *Server) getCurrentSerial() (uint32, bool) {
	return s.roaCurrentSerial, len(s.roaListSerial) > 0
}

func (s *Server) GenerateSerial() uint32 {
	s.roalock.RLock()
	newserial := s.generateSerial()
	s.roalock.RUnlock()
	return newserial
}

func (s *Server) generateSerial() uint32 {
	newserial := s.roaCurrentSerial
	if !s.manualserial && len(s.roaListSerial) > 0 {
		newserial = s.roaListSerial[len(s.roaListSerial)-1] + 1
	}
	return newserial
}

func (s *Server) setSerial(serial uint32) {
	s.roaCurrentSerial = serial
}

// This function sets the serial. Function must
// be called before the ROAs data is added.
func (s *Server) SetSerial(serial uint32) {
	s.roalock.RLock()
	//s.roaListSerial = make([]uint32, 0)
	s.setSerial(serial)
	s.roalock.RUnlock()
}

func (s *Server) AddROAs(roas []ROA) {
	s.roalock.RLock()
	curDiff := make([]ROA, 0)

	roaCurrent := s.roaCurrent

	added, removed, unchanged := ComputeDiff(roas, roaCurrent)
	if s.log != nil && s.logverbose {
		s.log.Debugf("Computed diff: added (%v), removed (%v), unchanged (%v)", added, removed, unchanged)
	} else if s.log != nil {
		s.log.Debugf("Computed diff: added (%d), removed (%d), unchanged (%d)", len(added), len(removed), len(unchanged))
	}
	curDiff = append(added, removed...)
	s.roalock.RUnlock()

	s.AddROAsDiff(curDiff)
}

func (s *Server) addSerial(serial uint32) []uint32 {
	removed := make([]uint32, 0)
	if len(s.roaListSerial) >= s.keepDiff && s.keepDiff > 0 {
		removeDiff := len(s.roaListSerial) - s.keepDiff
		removed = s.roaListSerial[0:removeDiff]
		s.roaListSerial = s.roaListSerial[removeDiff:]
	}
	s.roaListSerial = append(s.roaListSerial, serial)
	return removed
}

func (s *Server) AddROAsDiff(diff []ROA) {
	s.roalock.RLock()
	nextDiff := make([][]ROA, len(s.roaListDiff))
	for i, prevRoas := range s.roaListDiff {
		nextDiff[i] = ApplyDiff(diff, prevRoas)
	}
	newRoaCurrent := ApplyDiff(diff, s.roaCurrent)
	curserial, _ := s.getCurrentSerial()
	s.roalock.RUnlock()

	s.roalock.Lock()
	newserial := s.generateSerial()
	removed := s.addSerial(newserial)

	nextDiff = append(nextDiff, diff)
	if len(nextDiff) >= s.keepDiff && s.keepDiff > 0 {
		nextDiff = nextDiff[len(removed):]
	}

	s.roaMapSerial[curserial] = len(nextDiff) - 1

	if len(removed) > 0 {
		for k, v := range s.roaMapSerial {
			if k != curserial {
				s.roaMapSerial[k] = v - len(removed)
			}
		}
	}

	for _, removeSerial := range removed {
		delete(s.roaMapSerial, removeSerial)
	}
	s.roaListDiff = nextDiff
	s.roaCurrent = newRoaCurrent
	s.setSerial(newserial)
	s.roalock.Unlock()
}

func (s *Server) SetBaseVersion(version uint8) {
	s.baseVersion = version
}

func (s *Server) SetVersionEnforced(adapt bool) {
	s.enforceVersion = adapt
}

func (s *Server) SetMaxConnections(maxconn int) {
	if s.connected > maxconn {
		todisconnect := s.connected - maxconn
		clients := s.GetClientList()
		if s.log != nil {
			s.log.Debugf("Too many clients connected, disconnecting first %v", todisconnect)
		}
		for i := 0; i < todisconnect; i++ {
			if len(clients) > i {
				clients[i].Disconnect()
			}
		}
	}
	s.maxconn = maxconn
}

func (s *Server) GetMaxConnections() int {
	return s.maxconn
}

func (s *Server) SetSessionId(sessId uint16) {
	s.sessId = sessId
}

func (s *Server) ClientConnected(c *Client) {
	s.clientlock.Lock()
	s.clients = append(s.clients, c)
	s.connected++
	s.clientlock.Unlock()

	if s.handler != nil {
		s.handler.ClientConnected(c)
	}
}

func (s *Server) ClientDisconnected(c *Client) {
	s.clientlock.Lock()
	tmpclients := make([]*Client, 0)
	for _, cc := range s.clients {
		if cc != c {
			tmpclients = append(tmpclients, cc)
		}
	}
	s.clients = tmpclients
	s.connected--
	s.clientlock.Unlock()

	if s.handler != nil {
		s.handler.ClientDisconnected(c)
	}
}

func (s *Server) HandlePDU(c *Client, pdu PDU) {
	if s.enforceVersion && c.GetVersion() != s.baseVersion {
		// Enforce a single version
		if s.log != nil {
			s.log.Debugf("Client %v uses version %v and server is using %v", c.String(), c.GetVersion(), s.baseVersion)
		}
		c.SendWrongVersionError()
		c.Disconnect()
	}
	if c.GetVersion() > s.baseVersion {
		// Downgrade
		c.SetVersion(s.baseVersion)
	}

	if s.handler != nil {
		s.handler.HandlePDU(c, pdu)
	}
}

func (s *Server) RequestCache(c *Client) {
	if s.simpleHandler != nil {
		s.simpleHandler.RequestCache(c)
	}
}

func (s *Server) RequestNewVersion(c *Client, sessionId uint16, serial uint32) {
	if s.simpleHandler != nil {
		s.simpleHandler.RequestNewVersion(c, sessionId, serial)
	}
}

func (s *Server) Start(bind string) error {
	tcplist, err := net.Listen("tcp", bind)
	if err != nil {
		return err
	}
	return s.loopTCP(tcplist, "tcp", s.acceptClientTCP)
}

func (s *Server) acceptClientTCP(tcpconn net.Conn) error {
	client := ClientFromConn(tcpconn, s, s)
	client.log = s.log
	if s.enforceVersion {
		client.SetVersion(s.baseVersion)
	}
	client.SetIntervals(s.pduRefreshInterval, s.pduRetryInterval, s.pduExpireInterval)
	go client.Start()
	return nil
}

func (s *Server) acceptClientSSH(tcpconn net.Conn) error {
	_, chans, reqs, err := ssh.NewServerConn(tcpconn, s.sshconfig)
	if err != nil {
		return err
	}

	go func() {
		s.connected++
		cont := true
		for cont {
			select {
			case req := <-reqs:
				if req != nil && req.WantReply {
					req.Reply(false, nil)
				} else if req == nil {
					cont = false
					break
				}
			case newChannel := <-chans:
				if newChannel != nil && newChannel.ChannelType() != "session" {
					newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
					continue
				} else if newChannel == nil {
					cont = false
					break
				}
				channel, requests, err := newChannel.Accept()
				if err != nil {
					if s.log != nil {
						s.log.Errorf("Could not accept channel: %v", err)
					}
					cont = false
					break
				}
				for req := range requests {
					if req != nil && req.Type == "subsystem" && bytes.Equal(req.Payload, []byte{0, 0, 0, 8, 114, 112, 107, 105, 45, 114, 116, 114}) {
						err := req.Reply(true, nil)
						if err != nil {
							if s.log != nil {
								s.log.Errorf("Could not accept channel: %v", err)
							}
							cont = false
							break
						}
						client := ClientFromConnSSH(tcpconn, channel, s, s)
						client.log = s.log
						if s.enforceVersion {
							client.SetVersion(s.baseVersion)
						}
						client.SetIntervals(s.pduRefreshInterval, s.pduRetryInterval, s.pduExpireInterval)
						client.Start()
					} else {
						cont = false
						break
					}

				}
			}
		}
		s.connected--
		tcpconn.Close()
	}()
	return nil
}

type ClientCallback func(net.Conn) error

func (s *Server) loopTCP(tcplist net.Listener, logEnv string, clientCallback ClientCallback) error {
	for {
		tcpconn, err := tcplist.Accept()
		if err != nil {
			if s.log != nil {
				s.log.Errorf("Failed to accept %s connection: %s", logEnv, err)
			}
			continue
		}

		if s.maxconn > 0 && s.connected >= s.maxconn {
			if s.log != nil {
				s.log.Warnf("Could not accept %s connection from %v (not enough slots available: %d)", logEnv, tcpconn.RemoteAddr(), s.maxconn)
			}
			tcpconn.Close()
		} else {
			if s.log != nil {
				s.log.Infof("Accepted %s connection from %v (%d/%d)", logEnv, tcpconn.RemoteAddr(), s.connected+1, s.maxconn)
			}
			if clientCallback != nil {
				err := clientCallback(tcpconn)
				if err != nil && s.log != nil {
					s.log.Errorf("Error with %s client %v: %v", logEnv, tcpconn.RemoteAddr(), err)
				}
			}
		}
	}
	return nil
}

func (s *Server) StartSSH(bind string, config *ssh.ServerConfig) error {
	tcplist, err := net.Listen("tcp", bind)
	if err != nil {
		return err
	}
	s.sshconfig = config
	return s.loopTCP(tcplist, "ssh", s.acceptClientSSH)
}

func (s *Server) StartTLS(bind string, config *tls.Config) error {
	tcplist, err := tls.Listen("tcp", bind, config)
	if err != nil {
		return err
	}
	return s.loopTCP(tcplist, "tls", s.acceptClientTCP)
}

func (s *Server) GetClientList() []*Client {
	s.clientlock.RLock()
	list := make([]*Client, len(s.clients))
	for i, c := range s.clients {
		list[i] = c
	}
	s.clientlock.RUnlock()
	return list
}

func (s *Server) NotifyClientsLatest() {
	serial, _ := s.GetCurrentSerial(s.sessId)
	s.NotifyClients(serial)
}

func (s *Server) NotifyClients(serialNumber uint32) {
	clients := s.GetClientList()
	for _, c := range clients {
		c.Notify(s.sessId, serialNumber)
	}
}

func (s *Server) SendPDU(pdu PDU) {
	for _, client := range s.clients {
		client.SendPDU(pdu)
	}
}

func ClientFromConn(tcpconn net.Conn, handler RTRServerEventHandler, simpleHandler RTREventHandler) *Client {
	return &Client{
		tcpconn:       tcpconn,
		rd:            tcpconn,
		wr:            tcpconn,
		handler:       handler,
		simpleHandler: simpleHandler,
		transmits:     make(chan PDU, 256),
		quit:          make(chan bool),
	}
}

func ClientFromConnSSH(tcpconn net.Conn, channel ssh.Channel, handler RTRServerEventHandler, simpleHandler RTREventHandler) *Client {
	client := ClientFromConn(tcpconn, handler, simpleHandler)
	client.rd = channel
	client.wr = channel
	return client
}

type Client struct {
	connected     bool
	version       uint8
	versionset    bool
	tcpconn       net.Conn
	rd            io.Reader
	wr            io.Writer
	handler       RTRServerEventHandler
	simpleHandler RTREventHandler
	curserial     uint32

	transmits chan PDU
	quit      chan bool

	enforceVersion      bool
	disableVersionCheck bool

	refreshInterval uint32
	retryInterval   uint32
	expireInterval  uint32

	log Logger
}

func (c *Client) String() string {
	return fmt.Sprintf("%v (v%v) / Serial: %v", c.tcpconn.RemoteAddr(), c.version, c.curserial)
}

func (c *Client) GetRemoteAddress() net.Addr {
	return c.tcpconn.RemoteAddr()
}

func (c *Client) GetLocalAddress() net.Addr {
	return c.tcpconn.LocalAddr()
}

func (c *Client) GetVersion() uint8 {
	return c.version
}

func (c *Client) SetIntervals(refreshInterval uint32, retryInterval uint32, expireInterval uint32) {
	c.refreshInterval = refreshInterval
	c.retryInterval = retryInterval
	c.expireInterval = expireInterval
}

func (c *Client) SetVersion(newversion uint8) {
	c.versionset = true
	c.version = newversion
}

func (c *Client) SetDisableVersionCheck(disableCheck bool) {
	c.disableVersionCheck = disableCheck
}

func (c *Client) checkVersion(newversion uint8) {
	if (!c.versionset || newversion == c.version) && (newversion == PROTOCOL_VERSION_1 || newversion == PROTOCOL_VERSION_0) {
		c.SetVersion(newversion)
	} else {
		if c.log != nil {
			c.log.Debugf("%v: has bad version (received: v%v, current: v%v) error", c.String(), newversion, c.version)
		}
		c.SendWrongVersionError()
		c.Disconnect()
	}
}

func (c *Client) passSimpleHandler(pdu PDU) {
	if c.simpleHandler != nil {
		switch pduConv := pdu.(type) {
		case *PDUSerialQuery:
			c.simpleHandler.RequestNewVersion(c, pduConv.SessionId, pduConv.SerialNumber)
		case *PDUResetQuery:
			c.simpleHandler.RequestCache(c)
		default:
			// not a proper client packet
		}
	}
}

func (c *Client) sendLoop() {
	for c.connected {
		select {
		case pdu := <-c.transmits:
			c.wr.Write(pdu.Bytes())
		case <-c.quit:
			break
		}
	}
}

func (c *Client) Start() {
	c.connected = true
	if c.handler != nil {
		c.handler.ClientConnected(c)
	}

	go c.sendLoop()

	buf := make([]byte, 8000)
	for c.connected {
		// Remove this?
		length, err := c.rd.Read(buf)
		if err != nil || length == 0 {
			if c.log != nil {
				c.log.Debugf("Error %v", err)
			}
			c.Disconnect()
			return
		}

		pkt := buf[0:length]
		dec, err := DecodeBytes(pkt)
		if err != nil || dec == nil {
			if c.log != nil {
				c.log.Errorf("Error %v", err)
			}
			c.Disconnect()
			continue
		}
		if !c.disableVersionCheck {
			c.checkVersion(dec.GetVersion())
		}
		if c.log != nil {
			c.log.Debugf("%v: Received %v", c.String(), dec)
		}

		if c.enforceVersion {
			if !IsCorrectPDUVersion(dec, c.version) {
				if c.log != nil {
					c.log.Debugf("Bad version error")
				}
				c.SendWrongVersionError()
				c.Disconnect()
			}
		}

		switch pduconv := dec.(type) {
		case *PDUSerialQuery:
			c.curserial = pduconv.SerialNumber
		}

		if c.handler != nil {
			c.handler.HandlePDU(c, dec)
		}

		c.passSimpleHandler(dec)
	}
}

func (c *Client) Notify(sessionId uint16, serialNumber uint32) {
	pdu := &PDUSerialNotify{
		SessionId:    sessionId,
		SerialNumber: serialNumber,
	}
	c.SendPDU(pdu)
}

type ROA struct {
	Prefix net.IPNet
	MaxLen uint8
	ASN    uint32
	Flags  uint8
}

func (r ROA) String() string {
	return fmt.Sprintf("ROA %v -> /%v, AS%v, Flags: %v", r.Prefix.String(), r.MaxLen, r.ASN, r.Flags)
}

func (r1 ROA) Equals(r2 ROA) bool {
	return r1.MaxLen == r2.MaxLen && r1.ASN == r2.ASN && bytes.Equal(r1.Prefix.IP, r2.Prefix.IP) && bytes.Equal(r1.Prefix.Mask, r2.Prefix.Mask)
}

func (r1 ROA) Copy() ROA {
	newprefix := net.IPNet{
		IP:   make([]byte, len(r1.Prefix.IP)),
		Mask: make([]byte, len(r1.Prefix.Mask)),
	}
	copy(newprefix.IP, r1.Prefix.IP)
	copy(newprefix.Mask, r1.Prefix.Mask)
	return ROA{
		Prefix: newprefix,
		ASN:    r1.ASN,
		MaxLen: r1.MaxLen,
		Flags:  r1.Flags}
}

func (c *Client) SendROAs(sessionId uint16, serialNumber uint32, roas []ROA) {
	pduBegin := &PDUCacheResponse{
		SessionId: sessionId,
	}
	c.SendPDU(pduBegin)
	for _, roa := range roas {
		c.SendROA(roa)
	}
	pduEnd := &PDUEndOfData{
		SessionId:    sessionId,
		SerialNumber: serialNumber,

		RefreshInterval: c.refreshInterval,
		RetryInterval:   c.retryInterval,
		ExpireInterval:  c.expireInterval,
	}
	c.SendPDU(pduEnd)
}

func (c *Client) SendCacheReset() {
	pdu := &PDUCacheReset{}
	c.SendPDU(pdu)
}

func (c *Client) SendInternalError() {
	pdu := &PDUErrorReport{
		ErrorCode: PDU_ERROR_INTERNALERR,
		ErrorMsg:  "Unknown internal error",
	}
	c.SendPDU(pdu)
}

func (c *Client) SendNoDataError() {
	pdu := &PDUErrorReport{
		ErrorCode: PDU_ERROR_NODATA,
		ErrorMsg:  "No data available",
	}
	c.SendPDU(pdu)
}

func (c *Client) SendWrongVersionError() {
	pdu := &PDUErrorReport{
		ErrorCode: PDU_ERROR_BADPROTOVERSION,
		ErrorMsg:  "Bad protocol version",
	}
	c.SendPDU(pdu)
}

func (c *Client) SendROA(roa ROA) {
	if roa.Prefix.IP.To4() == nil && roa.Prefix.IP.To16() != nil {
		pdu := &PDUIPv6Prefix{
			Flags:  roa.Flags,
			MaxLen: roa.MaxLen,
			ASN:    roa.ASN,
			Prefix: roa.Prefix,
		}
		c.SendPDU(pdu)
	} else if roa.Prefix.IP.To4() != nil {
		pdu := &PDUIPv4Prefix{
			Flags:  roa.Flags,
			MaxLen: roa.MaxLen,
			ASN:    roa.ASN,
			Prefix: roa.Prefix,
		}
		c.SendPDU(pdu)
	}
}

func (c *Client) SendRawPDU(pdu PDU) {
	//c.tcpconn.Write(pdu.Bytes())
	c.transmits <- pdu
}

func (c *Client) SendPDU(pdu PDU) {
	pdu.SetVersion(c.version)
	c.SendRawPDU(pdu)
}

func (c *Client) Disconnect() {
	c.connected = false
	if c.log != nil {
		c.log.Infof("Disconnecting client %v", c.String())
	}
	if c.handler != nil {
		c.handler.ClientDisconnected(c)
	}
	select {
	case c.quit <- true:
	default:

	}

	c.tcpconn.Close()
}