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// Copyright 2018 the u-root Authors and Andrea Barberio. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build go1.12
package nclient6
import (
"bytes"
"context"
"fmt"
"net"
"sync"
"testing"
"time"
"github.com/hugelgupf/socketpair"
"github.com/insomniacslk/dhcp/dhcpv6"
"github.com/insomniacslk/dhcp/dhcpv6/server6"
"github.com/stretchr/testify/require"
)
type handler struct {
mu sync.Mutex
received []*dhcpv6.Message
// Each received packet can have more than one response (in theory,
// from different servers sending different Advertise, for example).
responses [][]*dhcpv6.Message
}
func (h *handler) handle(conn net.PacketConn, peer net.Addr, msg dhcpv6.DHCPv6) {
h.mu.Lock()
defer h.mu.Unlock()
m := msg.(*dhcpv6.Message)
h.received = append(h.received, m)
if len(h.responses) > 0 {
resps := h.responses[0]
// What should we send in response?
for _, resp := range resps {
if _, err := conn.WriteTo(resp.ToBytes(), peer); err != nil {
panic(err)
}
}
h.responses = h.responses[1:]
}
}
func serveAndClient(ctx context.Context, responses [][]*dhcpv6.Message, opt ...ClientOpt) (*Client, net.PacketConn) {
// Fake connection between client and server. No raw sockets, no port
// weirdness.
clientRawConn, serverRawConn, err := socketpair.PacketSocketPair()
if err != nil {
panic(err)
}
o := []ClientOpt{WithRetry(1), WithTimeout(2 * time.Second)}
o = append(o, opt...)
mc, err := NewWithConn(clientRawConn, net.HardwareAddr{0xa, 0xb, 0xc, 0xd, 0xe, 0xf}, o...)
if err != nil {
panic(err)
}
h := &handler{
responses: responses,
}
s, err := server6.NewServer("", nil, h.handle, server6.WithConn(serverRawConn))
if err != nil {
panic(err)
}
go func() {
if err := s.Serve(); err != nil {
panic(err)
}
}()
return mc, serverRawConn
}
func ComparePacket(got *dhcpv6.Message, want *dhcpv6.Message) 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 []*dhcpv6.Message, want []*dhcpv6.Message) 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 newPacket(xid dhcpv6.TransactionID) *dhcpv6.Message {
p, err := dhcpv6.NewMessage()
if err != nil {
panic(fmt.Sprintf("newpacket: %v", err))
}
p.TransactionID = xid
return p
}
func withBufferCap(n int) ClientOpt {
return func(c *Client) {
c.bufferCap = n
}
}
func TestSendAndReadUntil(t *testing.T) {
for _, tt := range []struct {
desc string
send *dhcpv6.Message
server []*dhcpv6.Message
// If want is nil, we assume server contains what is wanted.
want *dhcpv6.Message
wantErr error
}{
{
desc: "two response packets",
send: newPacket([3]byte{0x33, 0x33, 0x33}),
server: []*dhcpv6.Message{
newPacket([3]byte{0x33, 0x33, 0x33}),
newPacket([3]byte{0x33, 0x33, 0x33}),
},
want: newPacket([3]byte{0x33, 0x33, 0x33}),
},
{
desc: "one response packet",
send: newPacket([3]byte{0x33, 0x33, 0x33}),
server: []*dhcpv6.Message{
newPacket([3]byte{0x33, 0x33, 0x33}),
},
want: newPacket([3]byte{0x33, 0x33, 0x33}),
},
{
desc: "one response packet, one invalid XID",
send: newPacket([3]byte{0x33, 0x33, 0x33}),
server: []*dhcpv6.Message{
newPacket([3]byte{0x77, 0x33, 0x33}),
newPacket([3]byte{0x33, 0x33, 0x33}),
},
want: newPacket([3]byte{0x33, 0x33, 0x33}),
},
{
desc: "discard wrong XID",
send: newPacket([3]byte{0x33, 0x33, 0x33}),
server: []*dhcpv6.Message{
newPacket([3]byte{0, 0, 0}),
},
want: nil,
wantErr: ErrNoResponse,
},
{
desc: "no response, timeout",
send: newPacket([3]byte{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, [][]*dhcpv6.Message{tt.server},
// Use an unbuffered channel to make sure we
// have no deadlocks.
withBufferCap(0))
defer mc.Close()
rcvd, err := mc.SendAndRead(context.Background(), AllDHCPServers, 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 TestSimpleSendAndReadDiscardGarbage(t *testing.T) {
pkt := newPacket([3]byte{0x33, 0x33, 0x33})
responses := []*dhcpv6.Message{
newPacket([3]byte{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, [][]*dhcpv6.Message{responses})
defer mc.Close()
// Too short for valid DHCPv4 packet.
_, err := udpConn.WriteTo([]byte{0x01}, nil)
require.NoError(t, err)
rcvd, err := mc.SendAndRead(context.Background(), AllDHCPServers, pkt, nil)
if err != nil {
t.Error(err)
}
if err := ComparePacket(rcvd, responses[0]); err != nil {
t.Errorf("got unexpected packets: %v", err)
}
}
func TestMultipleSendAndReadOne(t *testing.T) {
for _, tt := range []struct {
desc string
send []*dhcpv6.Message
server [][]*dhcpv6.Message
wantErr []error
}{
{
desc: "two requests, two responses",
send: []*dhcpv6.Message{
newPacket([3]byte{0x33, 0x33, 0x33}),
newPacket([3]byte{0x44, 0x44, 0x44}),
},
server: [][]*dhcpv6.Message{
[]*dhcpv6.Message{ // Response for first packet.
newPacket([3]byte{0x33, 0x33, 0x33}),
},
[]*dhcpv6.Message{ // Response for second packet.
newPacket([3]byte{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.conn.Close()
for i, send := range tt.send {
rcvd, err := mc.SendAndRead(context.Background(), AllDHCPServers, send, nil)
if wantErr := tt.wantErr[i]; err != wantErr {
t.Errorf("SendAndReadOne(%v): got %v, want %v", send, err, wantErr)
}
if err := pktsExpected([]*dhcpv6.Message{rcvd}, tt.server[i]); err != nil {
t.Errorf("got unexpected packets: %v", err)
}
}
}
}
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