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TUN-6654: Support ICMPv6 on Linux and Darwin

This commit is contained in:
cthuang 2022-09-06 13:46:21 +01:00
parent a65f8bce7f
commit bf3d70d1d2
7 changed files with 232 additions and 68 deletions
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46
ingress/icmp_darwin.go
View File

@ -23,7 +23,6 @@ import (
"github.com/cloudflare/cloudflared/packet"
)
// TODO: TUN-6654 Extend support to IPv6
type icmpProxy struct {
srcFunnelTracker *packet.FunnelTracker
echoIDTracker *echoIDTracker
@ -180,25 +179,56 @@ func (ip *icmpProxy) Serve(ctx context.Context) error {
ip.srcFunnelTracker.ScheduleCleanup(ctx, ip.idleTimeout)
}()
buf := make([]byte, mtu)
icmpDecoder := packet.NewICMPDecoder()
for {
n, src, err := ip.conn.ReadFrom(buf)
n, from, err := ip.conn.ReadFrom(buf)
if err != nil {
return err
}
if err := ip.handleResponse(src, buf[:n]); err != nil {
ip.logger.Err(err).Str("src", src.String()).Msg("Failed to handle ICMP response")
reply, err := parseReply(from, buf[:n])
if err != nil {
ip.logger.Debug().Err(err).Str("dst", from.String()).Msg("Failed to parse ICMP reply, continue to parse as full packet")
// In unit test, we found out when the listener listens on 0.0.0.0, the socket reads the full packet after
// the second reply
if err := ip.handleFullPacket(icmpDecoder, buf[:n]); err != nil {
ip.logger.Err(err).Str("dst", from.String()).Msg("Failed to parse ICMP reply as full packet")
}
continue
}
if !isEchoReply(reply.msg) {
ip.logger.Debug().Str("dst", from.String()).Msgf("Drop ICMP %s from reply", reply.msg.Type)
continue
}
if ip.sendReply(reply); err != nil {
ip.logger.Error().Err(err).Str("dst", from.String()).Msg("Failed to send ICMP reply")
continue
}
}
}
func (ip *icmpProxy) handleResponse(from net.Addr, rawMsg []byte) error {
reply, err := parseReply(from, rawMsg)
func (ip *icmpProxy) handleFullPacket(decoder *packet.ICMPDecoder, rawPacket []byte) error {
icmpPacket, err := decoder.Decode(packet.RawPacket{Data: rawPacket})
if err != nil {
return err
}
funnel, exists := ip.srcFunnelTracker.Get(echoFunnelID(reply.echo.ID))
if !exists {
echo, err := getICMPEcho(icmpPacket.Message)
if err != nil {
return err
}
reply := echoReply{
from: icmpPacket.Src,
msg: icmpPacket.Message,
echo: echo,
}
if ip.sendReply(&reply); err != nil {
return err
}
return nil
}
func (ip *icmpProxy) sendReply(reply *echoReply) error {
funnel, ok := ip.srcFunnelTracker.Get(echoFunnelID(reply.echo.ID))
if !ok {
return packet.ErrFunnelNotFound
}
icmpFlow, err := toICMPEchoFlow(funnel)

24
ingress/icmp_linux.go
View File

@ -110,26 +110,26 @@ func (ip *icmpProxy) Serve(ctx context.Context) error {
func (ip *icmpProxy) listenResponse(flow *icmpEchoFlow, conn *icmp.PacketConn) error {
buf := make([]byte, mtu)
for {
n, src, err := conn.ReadFrom(buf)
n, from, err := conn.ReadFrom(buf)
if err != nil {
return err
}
if err := ip.handleResponse(flow, src, buf[:n]); err != nil {
ip.logger.Err(err).Str("dst", src.String()).Msg("Failed to handle ICMP response")
reply, err := parseReply(from, buf[:n])
if err != nil {
ip.logger.Error().Err(err).Str("dst", from.String()).Msg("Failed to parse ICMP reply")
continue
}
if !isEchoReply(reply.msg) {
ip.logger.Debug().Str("dst", from.String()).Msgf("Drop ICMP %s from reply", reply.msg.Type)
continue
}
if err := flow.returnToSrc(reply); err != nil {
ip.logger.Err(err).Str("dst", from.String()).Msg("Failed to send ICMP reply")
continue
}
}
}
func (ip *icmpProxy) handleResponse(flow *icmpEchoFlow, from net.Addr, rawMsg []byte) error {
reply, err := parseReply(from, rawMsg)
if err != nil {
return err
}
return flow.returnToSrc(reply)
}
// originSender wraps icmp.PacketConn to implement packet.FunnelUniPipe interface
type originSender struct {
conn *icmp.PacketConn

15
ingress/icmp_posix.go
View File

@ -113,8 +113,15 @@ type echoReply struct {
}
func parseReply(from net.Addr, rawMsg []byte) (*echoReply, error) {
// TODO: TUN-6654 Check for IPv6
msg, err := icmp.ParseMessage(int(layers.IPProtocolICMPv4), rawMsg)
fromAddr, ok := netipAddr(from)
if !ok {
return nil, fmt.Errorf("cannot convert %s to netip.Addr", from)
}
proto := layers.IPProtocolICMPv4
if fromAddr.Is6() {
proto = layers.IPProtocolICMPv6
}
msg, err := icmp.ParseMessage(int(proto), rawMsg)
if err != nil {
return nil, err
}
@ -122,10 +129,6 @@ func parseReply(from net.Addr, rawMsg []byte) (*echoReply, error) {
if err != nil {
return nil, err
}
fromAddr, ok := netipAddr(from)
if !ok {
return nil, fmt.Errorf("cannot convert %s to netip.Addr", from)
}
return &echoReply{
from: fromAddr,
msg: msg,

3
ingress/icmp_windows.go
View File

@ -145,6 +145,9 @@ type icmpProxy struct {
}
func newICMPProxy(listenIP netip.Addr, logger *zerolog.Logger, idleTimeout time.Duration) (ICMPProxy, error) {
if listenIP.Is6() {
return nil, fmt.Errorf("ICMPv6 not implemented for Windows")
}
handle, _, err := IcmpCreateFile_proc.Call()
// Windows procedure calls always return non-nil error constructed from the result of GetLastError.
// Caller need to inspect the primary returned value

67
ingress/origin_icmp_proxy.go
View File

@ -8,6 +8,8 @@ import (
"github.com/rs/zerolog"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
"github.com/cloudflare/cloudflared/packet"
)
@ -32,8 +34,65 @@ type ICMPProxy interface {
Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error
}
func NewICMPProxy(listenIP netip.Addr, logger *zerolog.Logger) (ICMPProxy, error) {
return newICMPProxy(listenIP, logger, funnelIdleTimeout)
type icmpRouter struct {
ipv4Proxy ICMPProxy
ipv6Proxy ICMPProxy
}
// NewICMPProxy doesn't return an error if either ipv4 proxy or ipv6 proxy can be created. The machine might only
// support one of them
func NewICMPProxy(logger *zerolog.Logger) (ICMPProxy, error) {
// TODO: TUN-6741: don't bind to all interface
ipv4Proxy, ipv4Err := newICMPProxy(netip.IPv4Unspecified(), logger, funnelIdleTimeout)
ipv6Proxy, ipv6Err := newICMPProxy(netip.IPv6Unspecified(), logger, funnelIdleTimeout)
if ipv4Err != nil && ipv6Err != nil {
return nil, fmt.Errorf("cannot create ICMPv4 proxy: %v nor ICMPv6 proxy: %v", ipv4Err, ipv6Err)
}
if ipv4Err != nil {
logger.Warn().Err(ipv4Err).Msg("failed to create ICMPv4 proxy, only ICMPv6 proxy is created")
ipv4Proxy = nil
}
if ipv6Err != nil {
logger.Warn().Err(ipv6Err).Msg("failed to create ICMPv6 proxy, only ICMPv4 proxy is created")
ipv6Proxy = nil
}
return &icmpRouter{
ipv4Proxy: ipv4Proxy,
ipv6Proxy: ipv6Proxy,
}, nil
}
func (ir *icmpRouter) Serve(ctx context.Context) error {
if ir.ipv4Proxy != nil && ir.ipv6Proxy != nil {
errC := make(chan error, 2)
go func() {
errC <- ir.ipv4Proxy.Serve(ctx)
}()
go func() {
errC <- ir.ipv6Proxy.Serve(ctx)
}()
return <-errC
}
if ir.ipv4Proxy != nil {
return ir.ipv4Proxy.Serve(ctx)
}
if ir.ipv6Proxy != nil {
return ir.ipv6Proxy.Serve(ctx)
}
return fmt.Errorf("ICMPv4 proxy and ICMPv6 proxy are both nil")
}
func (ir *icmpRouter) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error {
if pk.Dst.Is4() {
if ir.ipv4Proxy != nil {
return ir.ipv4Proxy.Request(pk, responder)
}
return fmt.Errorf("ICMPv4 proxy was not instantiated")
}
if ir.ipv6Proxy != nil {
return ir.ipv6Proxy.Request(pk, responder)
}
return fmt.Errorf("ICMPv6 proxy was not instantiated")
}
func getICMPEcho(msg *icmp.Message) (*icmp.Echo, error) {
@ -43,3 +102,7 @@ func getICMPEcho(msg *icmp.Message) (*icmp.Echo, error) {
}
return echo, nil
}
func isEchoReply(msg *icmp.Message) bool {
return msg.Type == ipv4.ICMPTypeEchoReply || msg.Type == ipv6.ICMPTypeEchoReply
}

124
ingress/origin_icmp_proxy_test.go
View File

@ -5,6 +5,8 @@ import (
"fmt"
"net"
"net/netip"
"runtime"
"strings"
"testing"
"github.com/google/gopacket/layers"
@ -12,6 +14,7 @@ import (
"github.com/stretchr/testify/require"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
"github.com/cloudflare/cloudflared/packet"
)
@ -19,6 +22,7 @@ import (
var (
noopLogger = zerolog.Nop()
localhostIP = netip.MustParseAddr("127.0.0.1")
localhostIPv6 = netip.MustParseAddr("::1")
)
// TestICMPProxyEcho makes sure we can send ICMP echo via the Request method and receives response via the
@ -28,12 +32,20 @@ var (
// is allowed in ping_group_range. See the following gist for how to do that:
// https://github.com/ValentinBELYN/icmplib/blob/main/docs/6-use-icmplib-without-privileges.md
func TestICMPProxyEcho(t *testing.T) {
testICMPProxyEcho(t, true)
if runtime.GOOS == "windows" {
t.Skip("TODO: TUN-6743: test ICMPv6 on Windows")
}
testICMPProxyEcho(t, false)
}
func testICMPProxyEcho(t *testing.T, sendIPv4 bool) {
const (
echoID = 36571
endSeq = 100
endSeq = 20
)
proxy, err := NewICMPProxy(localhostIP, &noopLogger)
proxy, err := NewICMPProxy(&noopLogger)
require.NoError(t, err)
proxyDone := make(chan struct{})
@ -48,37 +60,30 @@ func TestICMPProxyEcho(t *testing.T) {
respChan: make(chan []byte, 1),
}
ips := []packet.IP{
{
Src: localhostIP,
Dst: localhostIP,
Protocol: layers.IPProtocolICMPv4,
},
protocol := layers.IPProtocolICMPv6
if sendIPv4 {
protocol = layers.IPProtocolICMPv4
}
addrs, err := net.InterfaceAddrs()
require.NoError(t, err)
for _, addr := range addrs {
if ipnet, ok := addr.(*net.IPNet); ok {
ip := ipnet.IP
if !ipnet.IP.IsLoopback() && ip.IsPrivate() && ip.To4() != nil {
localIP := netip.MustParseAddr(ipnet.IP.String())
ips = append(ips, packet.IP{
localIPs := getLocalIPs(t, sendIPv4)
ips := make([]*packet.IP, len(localIPs))
for i, localIP := range localIPs {
ips[i] = &packet.IP{
Src: localIP,
Dst: localIP,
Protocol: layers.IPProtocolICMPv4,
})
break
}
Protocol: protocol,
}
}
var icmpType icmp.Type = ipv6.ICMPTypeEchoRequest
if sendIPv4 {
icmpType = ipv4.ICMPTypeEcho
}
for seq := 0; seq < endSeq; seq++ {
for i, ip := range ips {
pk := packet.ICMP{
IP: &ip,
IP: ip,
Message: &icmp.Message{
Type: ipv4.ICMPTypeEcho,
Type: icmpType,
Code: 0,
Body: &icmp.Echo{
ID: echoID + i,
@ -121,19 +126,52 @@ func TestICMPProxyRejectNotEcho(t *testing.T) {
},
},
}
proxy, err := NewICMPProxy(localhostIP, &noopLogger)
testICMPProxyRejectNotEcho(t, localhostIP, msgs)
msgsV6 := []icmp.Message{
{
Type: ipv6.ICMPTypeDestinationUnreachable,
Code: 3,
Body: &icmp.DstUnreach{
Data: []byte("original packet"),
},
},
{
Type: ipv6.ICMPTypeTimeExceeded,
Code: 0,
Body: &icmp.TimeExceeded{
Data: []byte("original packet"),
},
},
{
Type: ipv6.ICMPTypePacketTooBig,
Code: 0,
Body: &icmp.PacketTooBig{
MTU: 1280,
Data: []byte("original packet"),
},
},
}
testICMPProxyRejectNotEcho(t, localhostIPv6, msgsV6)
}
func testICMPProxyRejectNotEcho(t *testing.T, srcDstIP netip.Addr, msgs []icmp.Message) {
proxy, err := NewICMPProxy(&noopLogger)
require.NoError(t, err)
responder := echoFlowResponder{
decoder: packet.NewICMPDecoder(),
respChan: make(chan []byte),
}
protocol := layers.IPProtocolICMPv4
if srcDstIP.Is6() {
protocol = layers.IPProtocolICMPv6
}
for _, m := range msgs {
pk := packet.ICMP{
IP: &packet.IP{
Src: localhostIP,
Dst: localhostIP,
Protocol: layers.IPProtocolICMPv4,
Src: srcDstIP,
Dst: srcDstIP,
Protocol: protocol,
},
Message: &m,
}
@ -166,8 +204,40 @@ func (efr *echoFlowResponder) validate(t *testing.T, echoReq *packet.ICMP) {
require.Equal(t, decoded.Dst, echoReq.Src)
require.Equal(t, echoReq.Protocol, decoded.Protocol)
if echoReq.Type == ipv4.ICMPTypeEcho {
require.Equal(t, ipv4.ICMPTypeEchoReply, decoded.Type)
} else {
require.Equal(t, ipv6.ICMPTypeEchoReply, decoded.Type)
}
require.Equal(t, 0, decoded.Code)
if echoReq.Type == ipv4.ICMPTypeEcho {
require.NotZero(t, decoded.Checksum)
} else {
// For ICMPv6, the kernel will compute the checksum during transmission unless pseudo header is not nil
require.Zero(t, decoded.Checksum)
}
require.Equal(t, echoReq.Body, decoded.Body)
}
func getLocalIPs(t *testing.T, ipv4 bool) []netip.Addr {
interfaces, err := net.Interfaces()
require.NoError(t, err)
localIPs := []netip.Addr{}
for _, i := range interfaces {
// Skip TUN devices
if strings.Contains(i.Name, "tun") {
continue
}
addrs, err := i.Addrs()
require.NoError(t, err)
for _, addr := range addrs {
if ipnet, ok := addr.(*net.IPNet); ok && (ipnet.IP.IsPrivate() || ipnet.IP.IsLoopback()) {
if (ipv4 && ipnet.IP.To4() != nil) || (!ipv4 && ipnet.IP.To4() == nil) {
localIPs = append(localIPs, netip.MustParseAddr(ipnet.IP.String()))
}
}
}
}
return localIPs
}

9
supervisor/supervisor.go
View File

@ -4,7 +4,6 @@ import (
"context"
"errors"
"fmt"
"net/netip"
"strings"
"time"
@ -117,12 +116,8 @@ func NewSupervisor(config *TunnelConfig, orchestrator *orchestration.Orchestrato
connAwareLogger: log,
}
if useDatagramV2(config) {
// TODO: TUN-6654 listen for IPv6 and decide if it should listen on specific IP
listenIP, err := netip.ParseAddr("0.0.0.0")
if err != nil {
return nil, err
}
icmpProxy, err := ingress.NewICMPProxy(listenIP, config.Log)
// TODO: TUN-6701: Decouple upgrade of datagram v2 and using icmp proxy
icmpProxy, err := ingress.NewICMPProxy(config.Log)
if err != nil {
log.Logger().Warn().Err(err).Msg("Failed to create icmp proxy, will continue to use datagram v1")
} else {