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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package conn25
import (
"errors"
"net/netip"
"testing"
"tailscale.com/net/packet"
"tailscale.com/types/ipproto"
"tailscale.com/wgengine/filter"
)
type testConn25 struct {
clientTransitIPForMagicIPFn func(netip.Addr) (netip.Addr, error)
connectorRealIPForTransitIPConnectionFn func(netip.Addr, netip.Addr) (netip.Addr, error)
}
func (tc *testConn25) ClientTransitIPForMagicIP(magicIP netip.Addr) (netip.Addr, error) {
return tc.clientTransitIPForMagicIPFn(magicIP)
}
func (tc *testConn25) ConnectorRealIPForTransitIPConnection(srcIP netip.Addr, transitIP netip.Addr) (netip.Addr, error) {
return tc.connectorRealIPForTransitIPConnectionFn(srcIP, transitIP)
}
func TestHandlePacketFromTunDevice(t *testing.T) {
clientSrcIP := netip.MustParseAddr("100.70.0.1")
magicIP := netip.MustParseAddr("10.64.0.1")
unusedMagicIP := netip.MustParseAddr("10.64.0.2")
transitIP := netip.MustParseAddr("169.254.0.1")
realIP := netip.MustParseAddr("240.64.0.1")
clientPort := uint16(1234)
serverPort := uint16(80)
tests := []struct {
description string
p *packet.Parsed
throwMappingErr bool
expectedSrc netip.AddrPort
expectedDst netip.AddrPort
expectedFilterResponse filter.Response
}{
{
description: "accept-and-nat-new-client-flow-mapped-magic-ip",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(magicIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(transitIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "drop-unmapped-magic-ip",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(unusedMagicIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(unusedMagicIP, serverPort),
expectedFilterResponse: filter.Drop,
},
{
description: "accept-dont-nat-other-mapping-error",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(magicIP, serverPort),
},
throwMappingErr: true,
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(magicIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "accept-dont-nat-uninteresting-client-side",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(realIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(realIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "accept-dont-nat-uninteresting-connector-side",
p: &packet.Parsed{
Src: netip.AddrPortFrom(realIP, serverPort),
Dst: netip.AddrPortFrom(clientSrcIP, clientPort),
},
expectedSrc: netip.AddrPortFrom(realIP, serverPort),
expectedDst: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedFilterResponse: filter.Accept,
},
}
for _, tt := range tests {
t.Run(tt.description, func(t *testing.T) {
mock := &testConn25{}
mock.clientTransitIPForMagicIPFn = func(mip netip.Addr) (netip.Addr, error) {
if tt.throwMappingErr {
return netip.Addr{}, errors.New("synthetic mapping error")
}
if mip == magicIP {
return transitIP, nil
}
if mip == unusedMagicIP {
return netip.Addr{}, ErrUnmappedMagicIP
}
return netip.Addr{}, nil
}
dph := newDatapathHandler(mock, t.Logf)
tt.p.IPProto = ipproto.UDP
tt.p.IPVersion = 4
tt.p.StuffForTesting(40)
if want, got := tt.expectedFilterResponse, dph.HandlePacketFromTunDevice(tt.p); want != got {
t.Errorf("unexpected filter response: want %v, got %v", want, got)
}
if want, got := tt.expectedSrc, tt.p.Src; want != got {
t.Errorf("unexpected packet src: want %v, got %v", want, got)
}
if want, got := tt.expectedDst, tt.p.Dst; want != got {
t.Errorf("unexpected packet dst: want %v, got %v", want, got)
}
})
}
}
func TestHandlePacketFromWireGuard(t *testing.T) {
clientSrcIP := netip.MustParseAddr("100.70.0.1")
unknownSrcIP := netip.MustParseAddr("100.99.99.99")
transitIP := netip.MustParseAddr("169.254.0.1")
realIP := netip.MustParseAddr("240.64.0.1")
clientPort := uint16(1234)
serverPort := uint16(80)
tests := []struct {
description string
p *packet.Parsed
throwMappingErr bool
expectedSrc netip.AddrPort
expectedDst netip.AddrPort
expectedFilterResponse filter.Response
}{
{
description: "accept-and-nat-new-connector-flow-mapped-src-and-transit-ip",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(transitIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(realIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "drop-unmapped-src-and-transit-ip",
p: &packet.Parsed{
Src: netip.AddrPortFrom(unknownSrcIP, clientPort),
Dst: netip.AddrPortFrom(transitIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(unknownSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(transitIP, serverPort),
expectedFilterResponse: filter.Drop,
},
{
description: "accept-dont-nat-other-mapping-error",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(transitIP, serverPort),
},
throwMappingErr: true,
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(transitIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "accept-dont-nat-uninteresting-connector-side",
p: &packet.Parsed{
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(realIP, serverPort),
},
expectedSrc: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedDst: netip.AddrPortFrom(realIP, serverPort),
expectedFilterResponse: filter.Accept,
},
{
description: "accept-dont-nat-uninteresting-client-side",
p: &packet.Parsed{
Src: netip.AddrPortFrom(realIP, serverPort),
Dst: netip.AddrPortFrom(clientSrcIP, clientPort),
},
expectedSrc: netip.AddrPortFrom(realIP, serverPort),
expectedDst: netip.AddrPortFrom(clientSrcIP, clientPort),
expectedFilterResponse: filter.Accept,
},
}
for _, tt := range tests {
t.Run(tt.description, func(t *testing.T) {
mock := &testConn25{}
mock.connectorRealIPForTransitIPConnectionFn = func(src, tip netip.Addr) (netip.Addr, error) {
if tt.throwMappingErr {
return netip.Addr{}, errors.New("synthetic mapping error")
}
if tip == transitIP {
if src == clientSrcIP {
return realIP, nil
} else {
return netip.Addr{}, ErrUnmappedSrcAndTransitIP
}
}
return netip.Addr{}, nil
}
dph := newDatapathHandler(mock, t.Logf)
tt.p.IPProto = ipproto.UDP
tt.p.IPVersion = 4
tt.p.StuffForTesting(40)
if want, got := tt.expectedFilterResponse, dph.HandlePacketFromWireGuard(tt.p); want != got {
t.Errorf("unexpected filter response: want %v, got %v", want, got)
}
if want, got := tt.expectedSrc, tt.p.Src; want != got {
t.Errorf("unexpected packet src: want %v, got %v", want, got)
}
if want, got := tt.expectedDst, tt.p.Dst; want != got {
t.Errorf("unexpected packet dst: want %v, got %v", want, got)
}
})
}
}
func TestClientFlowCache(t *testing.T) {
getTransitIPCalled := false
clientSrcIP := netip.MustParseAddr("100.70.0.1")
magicIP := netip.MustParseAddr("10.64.0.1")
transitIP := netip.MustParseAddr("169.254.0.1")
clientPort := uint16(1234)
serverPort := uint16(80)
mock := &testConn25{}
mock.clientTransitIPForMagicIPFn = func(mip netip.Addr) (netip.Addr, error) {
if getTransitIPCalled {
t.Errorf("ClientGetTransitIPForMagicIP unexpectedly called more than once")
}
getTransitIPCalled = true
return transitIP, nil
}
dph := newDatapathHandler(mock, t.Logf)
outgoing := packet.Parsed{
IPProto: ipproto.UDP,
IPVersion: 4,
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(magicIP, serverPort),
}
outgoing.StuffForTesting(40)
o1 := outgoing
if dph.HandlePacketFromTunDevice(&o1) != filter.Accept {
t.Errorf("first call to HandlePacketFromTunDevice was not accepted")
}
if want, got := netip.AddrPortFrom(transitIP, serverPort), o1.Dst; want != got {
t.Errorf("unexpected packet dst after first call: want %v, got %v", want, got)
}
// The second call should use the cache.
o2 := outgoing
if dph.HandlePacketFromTunDevice(&o2) != filter.Accept {
t.Errorf("second call to HandlePacketFromTunDevice was not accepted")
}
if want, got := netip.AddrPortFrom(transitIP, serverPort), o2.Dst; want != got {
t.Errorf("unexpected packet dst after second call: want %v, got %v", want, got)
}
// Return traffic should have the Transit IP as the source,
// and be SNATed to the Magic IP.
incoming := &packet.Parsed{
IPProto: ipproto.UDP,
IPVersion: 4,
Src: netip.AddrPortFrom(transitIP, serverPort),
Dst: netip.AddrPortFrom(clientSrcIP, clientPort),
}
incoming.StuffForTesting(40)
if dph.HandlePacketFromWireGuard(incoming) != filter.Accept {
t.Errorf("call to HandlePacketFromWireGuard was not accepted")
}
if want, got := netip.AddrPortFrom(magicIP, serverPort), incoming.Src; want != got {
t.Errorf("unexpected packet src after second call: want %v, got %v", want, got)
}
}
func TestConnectorFlowCache(t *testing.T) {
getRealIPCalled := false
clientSrcIP := netip.MustParseAddr("100.70.0.1")
transitIP := netip.MustParseAddr("169.254.0.1")
realIP := netip.MustParseAddr("240.64.0.1")
clientPort := uint16(1234)
serverPort := uint16(80)
mock := &testConn25{}
mock.connectorRealIPForTransitIPConnectionFn = func(src, tip netip.Addr) (netip.Addr, error) {
if getRealIPCalled {
t.Errorf("ConnectorRealIPForTransitIPConnection unexpectedly called more than once")
}
getRealIPCalled = true
return realIP, nil
}
dph := newDatapathHandler(mock, t.Logf)
outgoing := packet.Parsed{
IPProto: ipproto.UDP,
IPVersion: 4,
Src: netip.AddrPortFrom(clientSrcIP, clientPort),
Dst: netip.AddrPortFrom(transitIP, serverPort),
}
outgoing.StuffForTesting(40)
o1 := outgoing
if dph.HandlePacketFromWireGuard(&o1) != filter.Accept {
t.Errorf("first call to HandlePacketFromWireGuard was not accepted")
}
if want, got := netip.AddrPortFrom(realIP, serverPort), o1.Dst; want != got {
t.Errorf("unexpected packet dst after first call: want %v, got %v", want, got)
}
// The second call should use the cache.
o2 := outgoing
if dph.HandlePacketFromWireGuard(&o2) != filter.Accept {
t.Errorf("second call to HandlePacketFromWireGuard was not accepted")
}
if want, got := netip.AddrPortFrom(realIP, serverPort), o2.Dst; want != got {
t.Errorf("unexpected packet dst after second call: want %v, got %v", want, got)
}
// Return traffic should have the Real IP as the source,
// and be SNATed to the Transit IP.
incoming := &packet.Parsed{
IPProto: ipproto.UDP,
IPVersion: 4,
Src: netip.AddrPortFrom(realIP, serverPort),
Dst: netip.AddrPortFrom(clientSrcIP, clientPort),
}
incoming.StuffForTesting(40)
if dph.HandlePacketFromTunDevice(incoming) != filter.Accept {
t.Errorf("call to HandlePacketFromTunDevice was not accepted")
}
if want, got := netip.AddrPortFrom(transitIP, serverPort), incoming.Src; want != got {
t.Errorf("unexpected packet src after second call: want %v, got %v", want, got)
}
}
|
