//go:build (linux && !android) || (darwin && !ios) || freebsd || openbsd || netbsd || dragonfly
package systemops
import (
"fmt"
"net"
"runtime"
"strings"
"testing"
"time"
"github.com/gopacket/gopacket"
"github.com/gopacket/gopacket/layers"
"github.com/gopacket/gopacket/pcap"
"github.com/miekg/dns"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
nbnet "github.com/netbirdio/netbird/util/net"
)
type PacketExpectation struct {
SrcIP net.IP
DstIP net.IP
SrcPort int
DstPort int
UDP bool
TCP bool
}
type testCase struct {
name string
destination string
expectedInterface string
dialer dialer
expectedPacket PacketExpectation
}
var testCases = []testCase{
{
name: "To external host without custom dialer via vpn",
destination: "192.0.2.1:53",
expectedInterface: expectedVPNint,
dialer: &net.Dialer{},
expectedPacket: createPacketExpectation("100.64.0.1", 12345, "192.0.2.1", 53),
},
{
name: "To external host with custom dialer via physical interface",
destination: "192.0.2.1:53",
expectedInterface: expectedExternalInt,
dialer: nbnet.NewDialer(),
expectedPacket: createPacketExpectation("192.168.0.1", 12345, "192.0.2.1", 53),
},
{
name: "To duplicate internal route with custom dialer via physical interface",
destination: "10.0.0.2:53",
expectedInterface: expectedInternalInt,
dialer: nbnet.NewDialer(),
expectedPacket: createPacketExpectation("192.168.1.1", 12345, "10.0.0.2", 53),
},
{
name: "To duplicate internal route without custom dialer via physical interface", // local route takes precedence
destination: "10.0.0.2:53",
expectedInterface: expectedInternalInt,
dialer: &net.Dialer{},
expectedPacket: createPacketExpectation("192.168.1.1", 12345, "10.0.0.2", 53),
},
{
name: "To unique vpn route with custom dialer via physical interface",
destination: "172.16.0.2:53",
expectedInterface: expectedExternalInt,
dialer: nbnet.NewDialer(),
expectedPacket: createPacketExpectation("192.168.0.1", 12345, "172.16.0.2", 53),
},
{
name: "To unique vpn route without custom dialer via vpn",
destination: "172.16.0.2:53",
expectedInterface: expectedVPNint,
dialer: &net.Dialer{},
expectedPacket: createPacketExpectation("100.64.0.1", 12345, "172.16.0.2", 53),
},
}
func TestRouting(t *testing.T) {
for _, tc := range testCases {
// todo resolve test execution on freebsd
if runtime.GOOS == "freebsd" {
t.Skip("skipping ", tc.name, " on freebsd")
}
t.Run(tc.name, func(t *testing.T) {
setupTestEnv(t)
filter := createBPFFilter(tc.destination)
handle := startPacketCapture(t, tc.expectedInterface, filter)
sendTestPacket(t, tc.destination, tc.expectedPacket.SrcPort, tc.dialer)
packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
packet, err := packetSource.NextPacket()
require.NoError(t, err)
verifyPacket(t, packet, tc.expectedPacket)
})
}
}
func createPacketExpectation(srcIP string, srcPort int, dstIP string, dstPort int) PacketExpectation {
return PacketExpectation{
SrcIP: net.ParseIP(srcIP),
DstIP: net.ParseIP(dstIP),
SrcPort: srcPort,
DstPort: dstPort,
UDP: true,
}
}
func startPacketCapture(t *testing.T, intf, filter string) *pcap.Handle {
t.Helper()
inactive, err := pcap.NewInactiveHandle(intf)
require.NoError(t, err, "Failed to create inactive pcap handle")
defer inactive.CleanUp()
err = inactive.SetSnapLen(1600)
require.NoError(t, err, "Failed to set snap length on inactive handle")
err = inactive.SetTimeout(time.Second * 10)
require.NoError(t, err, "Failed to set timeout on inactive handle")
err = inactive.SetImmediateMode(true)
require.NoError(t, err, "Failed to set immediate mode on inactive handle")
handle, err := inactive.Activate()
require.NoError(t, err, "Failed to activate pcap handle")
t.Cleanup(handle.Close)
err = handle.SetBPFFilter(filter)
require.NoError(t, err, "Failed to set BPF filter")
return handle
}
func sendTestPacket(t *testing.T, destination string, sourcePort int, dialer dialer) {
t.Helper()
if dialer == nil {
dialer = &net.Dialer{}
}
if sourcePort != 0 {
localUDPAddr := &net.UDPAddr{
IP: net.IPv4zero,
Port: sourcePort,
}
switch dialer := dialer.(type) {
case *nbnet.Dialer:
dialer.LocalAddr = localUDPAddr
case *net.Dialer:
dialer.LocalAddr = localUDPAddr
default:
t.Fatal("Unsupported dialer type")
}
}
msg := new(dns.Msg)
msg.Id = dns.Id()
msg.RecursionDesired = true
msg.Question = []dns.Question{
{Name: "example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET},
}
conn, err := dialer.Dial("udp", destination)
require.NoError(t, err, "Failed to dial UDP")
defer conn.Close()
data, err := msg.Pack()
require.NoError(t, err, "Failed to pack DNS message")
_, err = conn.Write(data)
if err != nil {
if strings.Contains(err.Error(), "required key not available") {
t.Logf("Ignoring WireGuard key error: %v", err)
return
}
t.Fatalf("Failed to send DNS query: %v", err)
}
}
func createBPFFilter(destination string) string {
host, port, err := net.SplitHostPort(destination)
if err != nil {
return fmt.Sprintf("udp and dst host %s and dst port %s", host, port)
}
return "udp"
}
func verifyPacket(t *testing.T, packet gopacket.Packet, exp PacketExpectation) {
t.Helper()
ipLayer := packet.Layer(layers.LayerTypeIPv4)
require.NotNil(t, ipLayer, "Expected IPv4 layer not found in packet")
ip, ok := ipLayer.(*layers.IPv4)
require.True(t, ok, "Failed to cast to IPv4 layer")
// Convert both source and destination IP addresses to 16-byte representation
expectedSrcIP := exp.SrcIP.To16()
actualSrcIP := ip.SrcIP.To16()
assert.Equal(t, expectedSrcIP, actualSrcIP, "Source IP mismatch")
expectedDstIP := exp.DstIP.To16()
actualDstIP := ip.DstIP.To16()
assert.Equal(t, expectedDstIP, actualDstIP, "Destination IP mismatch")
if exp.UDP {
udpLayer := packet.Layer(layers.LayerTypeUDP)
require.NotNil(t, udpLayer, "Expected UDP layer not found in packet")
udp, ok := udpLayer.(*layers.UDP)
require.True(t, ok, "Failed to cast to UDP layer")
assert.Equal(t, layers.UDPPort(exp.SrcPort), udp.SrcPort, "UDP source port mismatch")
assert.Equal(t, layers.UDPPort(exp.DstPort), udp.DstPort, "UDP destination port mismatch")
}
if exp.TCP {
tcpLayer := packet.Layer(layers.LayerTypeTCP)
require.NotNil(t, tcpLayer, "Expected TCP layer not found in packet")
tcp, ok := tcpLayer.(*layers.TCP)
require.True(t, ok, "Failed to cast to TCP layer")
assert.Equal(t, layers.TCPPort(exp.SrcPort), tcp.SrcPort, "TCP source port mismatch")
assert.Equal(t, layers.TCPPort(exp.DstPort), tcp.DstPort, "TCP destination port mismatch")
}
}