Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

2 files changed, 202 insertions, 0 deletions

diff --git a/pkg/tcpip/sample/tun_tcp_echo/BUILD b/pkg/tcpip/sample/tun_tcp_echo/BUILD
new file mode 100644
index 000000000..c51528a12
--- /dev/null
+++ b/pkg/tcpip/sample/tun_tcp_echo/BUILD
@@ -0,0 +1,20 @@
+package(licenses = ["notice"])  # BSD
+
+load("@io_bazel_rules_go//go:def.bzl", "go_binary")
+
+go_binary(
+    name = "tun_tcp_echo",
+    srcs = ["main.go"],
+    deps = [
+        "//pkg/tcpip",
+        "//pkg/tcpip/link/fdbased",
+        "//pkg/tcpip/link/rawfile",
+        "//pkg/tcpip/link/tun",
+        "//pkg/tcpip/network/arp",
+        "//pkg/tcpip/network/ipv4",
+        "//pkg/tcpip/network/ipv6",
+        "//pkg/tcpip/stack",
+        "//pkg/tcpip/transport/tcp",
+        "//pkg/waiter",
+    ],
+)
diff --git a/pkg/tcpip/sample/tun_tcp_echo/main.go b/pkg/tcpip/sample/tun_tcp_echo/main.go
new file mode 100644
index 000000000..10cd701af
--- /dev/null
+++ b/pkg/tcpip/sample/tun_tcp_echo/main.go
@@ -0,0 +1,182 @@
+// Copyright 2016 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.
+
+// This sample creates a stack with TCP and IPv4 protocols on top of a TUN
+// device, and listens on a port. Data received by the server in the accepted
+// connections is echoed back to the clients.
+package main
+
+import (
+	"flag"
+	"log"
+	"math/rand"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"gvisor.googlesource.com/gvisor/pkg/tcpip"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/link/fdbased"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/link/rawfile"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/link/tun"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/network/arp"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
+	"gvisor.googlesource.com/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.googlesource.com/gvisor/pkg/waiter"
+)
+
+var tap = flag.Bool("tap", false, "use tap istead of tun")
+var mac = flag.String("mac", "aa:00:01:01:01:01", "mac address to use in tap device")
+
+func echo(wq *waiter.Queue, ep tcpip.Endpoint) {
+	defer ep.Close()
+
+	// Create wait queue entry that notifies a channel.
+	waitEntry, notifyCh := waiter.NewChannelEntry(nil)
+
+	wq.EventRegister(&waitEntry, waiter.EventIn)
+	defer wq.EventUnregister(&waitEntry)
+
+	for {
+		v, err := ep.Read(nil)
+		if err != nil {
+			if err == tcpip.ErrWouldBlock {
+				<-notifyCh
+				continue
+			}
+
+			return
+		}
+
+		ep.Write(tcpip.SlicePayload(v), tcpip.WriteOptions{})
+	}
+}
+
+func main() {
+	flag.Parse()
+	if len(flag.Args()) != 3 {
+		log.Fatal("Usage: ", os.Args[0], " <tun-device> <local-address> <local-port>")
+	}
+
+	tunName := flag.Arg(0)
+	addrName := flag.Arg(1)
+	portName := flag.Arg(2)
+
+	rand.Seed(time.Now().UnixNano())
+
+	// Parse the mac address.
+	maddr, err := net.ParseMAC(*mac)
+	if err != nil {
+		log.Fatalf("Bad MAC address: %v", *mac)
+	}
+
+	// Parse the IP address. Support both ipv4 and ipv6.
+	parsedAddr := net.ParseIP(addrName)
+	if parsedAddr == nil {
+		log.Fatalf("Bad IP address: %v", addrName)
+	}
+
+	var addr tcpip.Address
+	var proto tcpip.NetworkProtocolNumber
+	if parsedAddr.To4() != nil {
+		addr = tcpip.Address(parsedAddr.To4())
+		proto = ipv4.ProtocolNumber
+	} else if parsedAddr.To16() != nil {
+		addr = tcpip.Address(parsedAddr.To16())
+		proto = ipv6.ProtocolNumber
+	} else {
+		log.Fatalf("Unknown IP type: %v", addrName)
+	}
+
+	localPort, err := strconv.Atoi(portName)
+	if err != nil {
+		log.Fatalf("Unable to convert port %v: %v", portName, err)
+	}
+
+	// Create the stack with ip and tcp protocols, then add a tun-based
+	// NIC and address.
+	s := stack.New([]string{ipv4.ProtocolName, ipv6.ProtocolName, arp.ProtocolName}, []string{tcp.ProtocolName})
+
+	mtu, err := rawfile.GetMTU(tunName)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var fd int
+	if *tap {
+		fd, err = tun.OpenTAP(tunName)
+	} else {
+		fd, err = tun.Open(tunName)
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	linkID := fdbased.New(&fdbased.Options{
+		FD:             fd,
+		MTU:            mtu,
+		EthernetHeader: *tap,
+		Address:        tcpip.LinkAddress(maddr),
+	})
+	if err := s.CreateNIC(1, linkID); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := s.AddAddress(1, proto, addr); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := s.AddAddress(1, arp.ProtocolNumber, arp.ProtocolAddress); err != nil {
+		log.Fatal(err)
+	}
+
+	// Add default route.
+	s.SetRouteTable([]tcpip.Route{
+		{
+			Destination: tcpip.Address(strings.Repeat("\x00", len(addr))),
+			Mask:        tcpip.Address(strings.Repeat("\x00", len(addr))),
+			Gateway:     "",
+			NIC:         1,
+		},
+	})
+
+	// Create TCP endpoint, bind it, then start listening.
+	var wq waiter.Queue
+	ep, e := s.NewEndpoint(tcp.ProtocolNumber, proto, &wq)
+	if err != nil {
+		log.Fatal(e)
+	}
+
+	defer ep.Close()
+
+	if err := ep.Bind(tcpip.FullAddress{0, "", uint16(localPort)}, nil); err != nil {
+		log.Fatal("Bind failed: ", err)
+	}
+
+	if err := ep.Listen(10); err != nil {
+		log.Fatal("Listen failed: ", err)
+	}
+
+	// Wait for connections to appear.
+	waitEntry, notifyCh := waiter.NewChannelEntry(nil)
+	wq.EventRegister(&waitEntry, waiter.EventIn)
+	defer wq.EventUnregister(&waitEntry)
+
+	for {
+		n, wq, err := ep.Accept()
+		if err != nil {
+			if err == tcpip.ErrWouldBlock {
+				<-notifyCh
+				continue
+			}
+
+			log.Fatal("Accept() failed:", err)
+		}
+
+		go echo(wq, n) // S/R-FIXME
+	}
+}