tcpip/network/ipv4/ipv4_test.go

// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

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}, stack.Options{})

	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,
	}})

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

	var wq waiter.Queue
	t.Run("WithoutPrimaryAddress", func(t *testing.T) {
		ep, err := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
		if err != nil {
			t.Fatal(err)
		}
		defer ep.Close()

		// Cannot connect using a broadcast address as the source.
		if err := ep.Connect(randomAddr); err != tcpip.ErrNoRoute {
			t.Errorf("got ep.Connect(...) = %v, want = %v", err, tcpip.ErrNoRoute)
		}

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

	t.Run("WithPrimaryAddress", func(t *testing.T) {
		ep, err := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &wq)
		if err != nil {
			t.Fatal(err)
		}
		defer ep.Close()

		// 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)
		}
		if err := ep.Connect(randomAddr); err != nil {
			t.Errorf("Connect failed: %v", err)
		}
	})
}