From 89df5a681c004a3772facc08de73d930636227be Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Thu, 21 Jan 2021 14:51:24 -0800
Subject: Queue packets in WritePackets when resolving link address

Test: integration_test.TestWritePacketsLinkResolution

Fixes #4458.

PiperOrigin-RevId: 353108826
---
 .../tests/integration/link_resolution_test.go      | 125 +++++++++++++++++++++
 1 file changed, 125 insertions(+)

(limited to 'pkg/tcpip/tests/integration')

diff --git a/pkg/tcpip/tests/integration/link_resolution_test.go b/pkg/tcpip/tests/integration/link_resolution_test.go
index af32d3009..7afc4702c 100644
--- a/pkg/tcpip/tests/integration/link_resolution_test.go
+++ b/pkg/tcpip/tests/integration/link_resolution_test.go
@@ -23,6 +23,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/checker"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/link/pipe"
@@ -32,6 +33,7 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
@@ -456,3 +458,126 @@ func TestGetLinkAddress(t *testing.T) {
 		})
 	}
 }
+
+func TestWritePacketsLinkResolution(t *testing.T) {
+	const (
+		host1NICID = 1
+		host2NICID = 4
+	)
+
+	tests := []struct {
+		name             string
+		netProto         tcpip.NetworkProtocolNumber
+		remoteAddr       tcpip.Address
+		expectedWriteErr *tcpip.Error
+	}{
+		{
+			name:             "IPv4",
+			netProto:         ipv4.ProtocolNumber,
+			remoteAddr:       ipv4Addr2.AddressWithPrefix.Address,
+			expectedWriteErr: nil,
+		},
+		{
+			name:             "IPv6",
+			netProto:         ipv6.ProtocolNumber,
+			remoteAddr:       ipv6Addr2.AddressWithPrefix.Address,
+			expectedWriteErr: nil,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			stackOpts := stack.Options{
+				NetworkProtocols:   []stack.NetworkProtocolFactory{arp.NewProtocol, ipv4.NewProtocol, ipv6.NewProtocol},
+				TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
+			}
+
+			host1Stack, host2Stack := setupStack(t, stackOpts, host1NICID, host2NICID)
+
+			var serverWQ waiter.Queue
+			serverWE, serverCH := waiter.NewChannelEntry(nil)
+			serverWQ.EventRegister(&serverWE, waiter.EventIn)
+			serverEP, err := host2Stack.NewEndpoint(udp.ProtocolNumber, test.netProto, &serverWQ)
+			if err != nil {
+				t.Fatalf("host2Stack.NewEndpoint(%d, %d, _): %s", udp.ProtocolNumber, test.netProto, err)
+			}
+			defer serverEP.Close()
+
+			serverAddr := tcpip.FullAddress{Port: 1234}
+			if err := serverEP.Bind(serverAddr); err != nil {
+				t.Fatalf("serverEP.Bind(%#v): %s", serverAddr, err)
+			}
+
+			r, err := host1Stack.FindRoute(host1NICID, "", test.remoteAddr, test.netProto, false /* multicastLoop */)
+			if err != nil {
+				t.Fatalf("host1Stack.FindRoute(%d, '', %s, %d, false): %s", host1NICID, test.remoteAddr, test.netProto, err)
+			}
+			defer r.Release()
+
+			data := []byte{1, 2}
+			var pkts stack.PacketBufferList
+			for _, d := range data {
+				pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
+					ReserveHeaderBytes: header.UDPMinimumSize + int(r.MaxHeaderLength()),
+					Data:               buffer.View([]byte{d}).ToVectorisedView(),
+				})
+				pkt.TransportProtocolNumber = udp.ProtocolNumber
+				length := uint16(pkt.Size())
+				udpHdr := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
+				udpHdr.Encode(&header.UDPFields{
+					SrcPort: 5555,
+					DstPort: serverAddr.Port,
+					Length:  length,
+				})
+				xsum := r.PseudoHeaderChecksum(udp.ProtocolNumber, length)
+				for _, v := range pkt.Data.Views() {
+					xsum = header.Checksum(v, xsum)
+				}
+				udpHdr.SetChecksum(^udpHdr.CalculateChecksum(xsum))
+
+				pkts.PushBack(pkt)
+			}
+
+			params := stack.NetworkHeaderParams{
+				Protocol: udp.ProtocolNumber,
+				TTL:      64,
+				TOS:      stack.DefaultTOS,
+			}
+
+			if n, err := r.WritePackets(nil /* gso */, pkts, params); err != nil {
+				t.Fatalf("r.WritePackets(nil, %#v, _): %s", params, err)
+			} else if want := pkts.Len(); want != n {
+				t.Fatalf("got r.WritePackets(nil, %#v, _) = %d, want = %d", n, params, want)
+			}
+
+			var writer bytes.Buffer
+			count := 0
+			for {
+				var rOpts tcpip.ReadOptions
+				res, err := serverEP.Read(&writer, rOpts)
+				if err != nil {
+					if err == tcpip.ErrWouldBlock {
+						// Should not have anymore bytes to read after we read the sent
+						// number of bytes.
+						if count == len(data) {
+							break
+						}
+
+						<-serverCH
+						continue
+					}
+
+					t.Fatalf("serverEP.Read(_, %#v): %s", rOpts, err)
+				}
+				count += res.Count
+			}
+
+			if got, want := host2Stack.Stats().UDP.PacketsReceived.Value(), uint64(len(data)); got != want {
+				t.Errorf("got host2Stack.Stats().UDP.PacketsReceived.Value() = %d, want = %d", got, want)
+			}
+			if diff := cmp.Diff(data, writer.Bytes()); diff != "" {
+				t.Errorf("read bytes mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
-- 
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