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