tcpip/network/ipv4/ipv4_test.go

// Copyright 2017 The Netstack Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package ipv4_test

import (
	"testing"

	"github.com/google/netstack/tcpip"
	"github.com/google/netstack/tcpip/header"
	"github.com/google/netstack/tcpip/link/channel"
	"github.com/google/netstack/tcpip/link/sniffer"
	"github.com/google/netstack/tcpip/network/ipv4"
	"github.com/google/netstack/tcpip/stack"
	"github.com/google/netstack/tcpip/transport/udp"
	"github.com/google/netstack/waiter"
)

func TestExcludeBroadcast(t *testing.T) {
	s := stack.New([]string{ipv4.ProtocolName}, []string{udp.ProtocolName})

	const defaultMTU = 65536
	id, _ := channel.New(256, defaultMTU, "")
	if testing.Verbose() {
		id = sniffer.New(id)
	}
	if err := s.CreateNIC(1, id); err != nil {
		t.Fatalf("CreateNIC failed: %v", err)
	}

	if err := s.AddAddress(1, ipv4.ProtocolNumber, header.IPv4Broadcast); err != nil {
		t.Fatalf("AddAddress failed: %v", err)
	}
	if err := s.AddAddress(1, ipv4.ProtocolNumber, header.IPv4Any); err != nil {
		t.Fatalf("AddAddress failed: %v", err)
	}

	s.SetRouteTable([]tcpip.Route{{
		Destination: "\x00\x00\x00\x00",
		Mask:        "\x00\x00\x00\x00",
		Gateway:     "",
		NIC:         1,
	}})

	var wq waiter.Queue
	ep, e := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
	if e != nil {
		t.Fatal(e)
	}

	randomAddr := tcpip.FullAddress{NIC: 1, Addr: "\x0a\x00\x00\x01", Port: 53}

	// Cannot connect using a broadcast address as the source.
	e = ep.Connect(randomAddr)
	if e == nil {
		t.Error(`connect succeeded, expected "no route"`)
	} else if e != tcpip.ErrNoRoute {
		t.Error(`connect failed with %v, expected "no route"`, e)
	}

	// However, we can bind to a broadcast address to listen.
	e = ep.Bind(tcpip.FullAddress{Addr: header.IPv4Broadcast, Port: 53, NIC: 1}, nil)
	if e != nil {
		t.Errorf("bind failed: %v", e)
	}

	ep.Close()
	ep, e = s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
	if e != nil {
		t.Fatal(e)
	}

	// Add a valid primary endpoint address, now we can connect.
	if err := s.AddAddress(1, ipv4.ProtocolNumber, "\x0a\x00\x00\x02"); err != nil {
		t.Fatalf("AddAddress failed: %v", err)
	}
	e = ep.Connect(randomAddr)
	if e != nil {
		t.Errorf("connect failed: %v", e)
	}
}