1 files changed, 151 insertions, 0 deletions
diff --git a/test/packetimpact/testbench/rawsockets.go b/test/packetimpact/testbench/rawsockets.go
new file mode 100644
index 000000000..0c7d0f979
--- /dev/null
+++ b/test/packetimpact/testbench/rawsockets.go
@@ -0,0 +1,151 @@
+// Copyright 2020 The gVisor Authors.
+//
+// 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 testbench
+
+import (
+	"encoding/binary"
+	"flag"
+	"math"
+	"net"
+	"testing"
+	"time"
+
+	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+var device = flag.String("device", "", "local device for test packets")
+
+// Sniffer can sniff raw packets on the wire.
+type Sniffer struct {
+	t  *testing.T
+	fd int
+}
+
+func htons(x uint16) uint16 {
+	buf := [2]byte{}
+	binary.BigEndian.PutUint16(buf[:], x)
+	return usermem.ByteOrder.Uint16(buf[:])
+}
+
+// NewSniffer creates a Sniffer connected to *device.
+func NewSniffer(t *testing.T) (Sniffer, error) {
+	flag.Parse()
+	snifferFd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL)))
+	if err != nil {
+		return Sniffer{}, err
+	}
+	return Sniffer{
+		t:  t,
+		fd: snifferFd,
+	}, nil
+}
+
+// maxReadSize should be large enough for the maximum frame size in bytes. If a
+// packet too large for the buffer arrives, the test will get a fatal error.
+const maxReadSize int = 65536
+
+// Recv tries to read one frame until the timeout is up.
+func (s *Sniffer) Recv(timeout time.Duration) []byte {
+	deadline := time.Now().Add(timeout)
+	for {
+		timeout = deadline.Sub(time.Now())
+		if timeout <= 0 {
+			return nil
+		}
+		whole, frac := math.Modf(timeout.Seconds())
+		tv := unix.Timeval{
+			Sec:  int64(whole),
+			Usec: int64(frac * float64(time.Microsecond/time.Second)),
+		}
+
+		if err := unix.SetsockoptTimeval(s.fd, unix.SOL_SOCKET, unix.SO_RCVTIMEO, &tv); err != nil {
+			s.t.Fatalf("can't setsockopt SO_RCVTIMEO: %s", err)
+		}
+
+		buf := make([]byte, maxReadSize)
+		nread, _, err := unix.Recvfrom(s.fd, buf, unix.MSG_TRUNC)
+		if err == unix.EINTR || err == unix.EAGAIN {
+			// There was a timeout.
+			continue
+		}
+		if err != nil {
+			s.t.Fatalf("can't read: %s", err)
+		}
+		if nread > maxReadSize {
+			s.t.Fatalf("received a truncated frame of %d bytes", nread)
+		}
+		return buf[:nread]
+	}
+}
+
+// Close the socket that Sniffer is using.
+func (s *Sniffer) Close() {
+	if err := unix.Close(s.fd); err != nil {
+		s.t.Fatalf("can't close sniffer socket: %s", err)
+	}
+	s.fd = -1
+}
+
+// Injector can inject raw frames.
+type Injector struct {
+	t  *testing.T
+	fd int
+}
+
+// NewInjector creates a new injector on *device.
+func NewInjector(t *testing.T) (Injector, error) {
+	flag.Parse()
+	ifInfo, err := net.InterfaceByName(*device)
+	if err != nil {
+		return Injector{}, err
+	}
+
+	var haddr [8]byte
+	copy(haddr[:], ifInfo.HardwareAddr)
+	sa := unix.SockaddrLinklayer{
+		Protocol: unix.ETH_P_IP,
+		Ifindex:  ifInfo.Index,
+		Halen:    uint8(len(ifInfo.HardwareAddr)),
+		Addr:     haddr,
+	}
+
+	injectFd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL)))
+	if err != nil {
+		return Injector{}, err
+	}
+	if err := unix.Bind(injectFd, &sa); err != nil {
+		return Injector{}, err
+	}
+	return Injector{
+		t:  t,
+		fd: injectFd,
+	}, nil
+}
+
+// Send a raw frame.
+func (i *Injector) Send(b []byte) {
+	if _, err := unix.Write(i.fd, b); err != nil {
+		i.t.Fatalf("can't write: %s", err)
+	}
+}
+
+// Close the underlying socket.
+func (i *Injector) Close() {
+	if err := unix.Close(i.fd); err != nil {
+		i.t.Fatalf("can't close sniffer socket: %s", err)
+	}
+	i.fd = -1
+}