badguardhome/internal/dhcpd/nclient4/client_test.go

346 lines
9.6 KiB
Go

// Copyright 2018 the u-root Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build linux
// github.com/hugelgupf/socketpair is Linux-only
// +build go1.12
package nclient4
import (
"bytes"
"context"
"fmt"
"net"
"sync"
"testing"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/testutil"
"github.com/hugelgupf/socketpair"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/insomniacslk/dhcp/dhcpv4/server4"
)
func TestMain(m *testing.M) {
testutil.DiscardLogOutput(m)
}
type handler struct {
mu sync.Mutex
received []*dhcpv4.DHCPv4
// Each received packet can have more than one response (in theory,
// from different servers sending different Advertise, for example).
responses [][]*dhcpv4.DHCPv4
}
func (h *handler) handle(conn net.PacketConn, peer net.Addr, m *dhcpv4.DHCPv4) {
h.mu.Lock()
defer h.mu.Unlock()
h.received = append(h.received, m)
if len(h.responses) > 0 {
for _, resp := range h.responses[0] {
_, _ = conn.WriteTo(resp.ToBytes(), peer)
}
h.responses = h.responses[1:]
}
}
func serveAndClient(ctx context.Context, responses [][]*dhcpv4.DHCPv4, opts ...ClientOpt) (*Client, net.PacketConn) {
// Fake PacketConn connection.
clientRawConn, serverRawConn, err := socketpair.PacketSocketPair()
if err != nil {
panic(err)
}
clientConn := NewBroadcastUDPConn(clientRawConn, &net.UDPAddr{Port: ClientPort})
serverConn := NewBroadcastUDPConn(serverRawConn, &net.UDPAddr{Port: ServerPort})
o := []ClientOpt{WithRetry(1), WithTimeout(2 * time.Second)}
o = append(o, opts...)
mc, err := NewWithConn(clientConn, net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf}, o...)
if err != nil {
panic(err)
}
h := &handler{responses: responses}
s, err := server4.NewServer("", nil, h.handle, server4.WithConn(serverConn))
if err != nil {
panic(err)
}
go func() {
_ = s.Serve()
}()
return mc, serverConn
}
func ComparePacket(got, want *dhcpv4.DHCPv4) error {
if got == nil && got == want {
return nil
}
if (want == nil || got == nil) && (got != want) {
return fmt.Errorf("packet got %v, want %v", got, want)
}
if !bytes.Equal(got.ToBytes(), want.ToBytes()) {
return fmt.Errorf("packet got %v, want %v", got, want)
}
return nil
}
func pktsExpected(got, want []*dhcpv4.DHCPv4) error {
if len(got) != len(want) {
return fmt.Errorf("got %d packets, want %d packets", len(got), len(want))
}
for i := range got {
if err := ComparePacket(got[i], want[i]); err != nil {
return err
}
}
return nil
}
func newPacketWeirdHWAddr(op dhcpv4.OpcodeType, xid dhcpv4.TransactionID) *dhcpv4.DHCPv4 {
p, err := dhcpv4.New()
if err != nil {
panic(fmt.Sprintf("newpacket: %v", err))
}
p.OpCode = op
p.TransactionID = xid
p.ClientHWAddr = net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 1, 2, 3, 4, 5, 6}
return p
}
func newPacket(op dhcpv4.OpcodeType, xid dhcpv4.TransactionID) *dhcpv4.DHCPv4 {
p, err := dhcpv4.New()
if err != nil {
panic(fmt.Sprintf("newpacket: %v", err))
}
p.OpCode = op
p.TransactionID = xid
p.ClientHWAddr = net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf}
return p
}
func withBufferCap(n int) ClientOpt {
return func(c *Client) (err error) {
c.bufferCap = n
return
}
}
func TestSendAndRead(t *testing.T) {
for _, tt := range []struct {
desc string
send *dhcpv4.DHCPv4
server []*dhcpv4.DHCPv4
// If want is nil, we assume server[0] contains what is wanted.
want *dhcpv4.DHCPv4
wantErr error
}{
{
desc: "two response packets",
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
server: []*dhcpv4.DHCPv4{
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
{
desc: "one response packet",
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
server: []*dhcpv4.DHCPv4{
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
{
desc: "one response packet, one invalid XID, one invalid opcode, one invalid hwaddr",
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
server: []*dhcpv4.DHCPv4{
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x77, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacketWeirdHWAddr(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
want: newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
{
desc: "discard wrong XID",
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
server: []*dhcpv4.DHCPv4{
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0, 0, 0, 0}),
},
want: nil, // Explicitly empty.
wantErr: ErrNoResponse,
},
{
desc: "no response, timeout",
send: newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
wantErr: ErrNoResponse,
},
} {
t.Run(tt.desc, func(t *testing.T) {
// Both server and client only get 2 seconds.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{tt.server},
// Use an unbuffered channel to make sure we
// have no deadlocks.
withBufferCap(0))
defer mc.Close()
rcvd, err := mc.SendAndRead(context.Background(), DefaultServers, tt.send, nil)
if err != tt.wantErr {
t.Error(err)
}
if err := ComparePacket(rcvd, tt.want); err != nil {
t.Errorf("got unexpected packets: %v", err)
}
})
}
}
func TestParallelSendAndRead(t *testing.T) {
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
// Both the server and client only get 2 seconds.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{},
WithTimeout(10*time.Second),
// Use an unbuffered channel to make sure nothing blocks.
withBufferCap(0))
defer mc.Close()
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
}
}()
wg.Add(1)
go func() {
defer wg.Done()
time.Sleep(4 * time.Second)
if err := mc.Close(); err != nil {
t.Errorf("closing failed: %v", err)
}
}()
wg.Wait()
}
func TestReuseXID(t *testing.T) {
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
// Both the server and client only get 2 seconds.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
mc, _ := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{})
defer mc.Close()
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
}
if _, err := mc.SendAndRead(context.Background(), DefaultServers, pkt, nil); err != ErrNoResponse {
t.Errorf("SendAndRead(%v) = %v, want %v", pkt, err, ErrNoResponse)
}
}
func TestSimpleSendAndReadDiscardGarbage(t *testing.T) {
pkt := newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33})
responses := newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33})
// Both the server and client only get 2 seconds.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
mc, udpConn := serveAndClient(ctx, [][]*dhcpv4.DHCPv4{{responses}})
defer mc.Close()
// Too short for valid DHCPv4 packet.
_, _ = udpConn.WriteTo([]byte{0x01}, nil)
_, _ = udpConn.WriteTo([]byte{0x01, 0x2}, nil)
rcvd, err := mc.SendAndRead(ctx, DefaultServers, pkt, nil)
if err != nil {
t.Errorf("SendAndRead(%v) = %v, want nil", pkt, err)
}
if err := ComparePacket(rcvd, responses); err != nil {
t.Errorf("got unexpected packets: %v", err)
}
}
func TestMultipleSendAndRead(t *testing.T) {
for _, tt := range []struct {
desc string
send []*dhcpv4.DHCPv4
server [][]*dhcpv4.DHCPv4
wantErr []error
}{
{
desc: "two requests, two responses",
send: []*dhcpv4.DHCPv4{
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x33, 0x33, 0x33, 0x33}),
newPacket(dhcpv4.OpcodeBootRequest, [4]byte{0x44, 0x44, 0x44, 0x44}),
},
server: [][]*dhcpv4.DHCPv4{
{ // Response for first packet.
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x33, 0x33, 0x33, 0x33}),
},
{ // Response for second packet.
newPacket(dhcpv4.OpcodeBootReply, [4]byte{0x44, 0x44, 0x44, 0x44}),
},
},
wantErr: []error{
nil,
nil,
},
},
} {
// Both server and client only get 2 seconds.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
mc, _ := serveAndClient(ctx, tt.server)
defer mc.Close()
for i, send := range tt.send {
ctx, cancel = context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
rcvd, err := mc.SendAndRead(ctx, DefaultServers, send, nil)
if wantErr := tt.wantErr[i]; err != wantErr {
t.Errorf("SendAndReadOne(%v): got %v, want %v", send, err, wantErr)
}
if err := pktsExpected([]*dhcpv4.DHCPv4{rcvd}, tt.server[i]); err != nil {
t.Errorf("got unexpected packets: %v", err)
}
}
}
}