diff options
Diffstat (limited to 'test/packetimpact/testbench')
| -rw-r--r-- | test/packetimpact/testbench/BUILD | 43 | ||||
| -rw-r--r-- | test/packetimpact/testbench/connections.go | 824 | ||||
| -rw-r--r-- | test/packetimpact/testbench/dut.go | 473 | ||||
| -rw-r--r-- | test/packetimpact/testbench/dut_client.go | 28 | ||||
| -rw-r--r-- | test/packetimpact/testbench/layers.go | 1157 | ||||
| -rw-r--r-- | test/packetimpact/testbench/layers_test.go | 395 | ||||
| -rw-r--r-- | test/packetimpact/testbench/rawsockets.go | 183 |
7 files changed, 3103 insertions, 0 deletions
diff --git a/test/packetimpact/testbench/BUILD b/test/packetimpact/testbench/BUILD new file mode 100644 index 000000000..3ceceb9d7 --- /dev/null +++ b/test/packetimpact/testbench/BUILD @@ -0,0 +1,43 @@ +load("//tools:defs.bzl", "go_library", "go_test") + +package( + default_visibility = ["//test/packetimpact:__subpackages__"], + licenses = ["notice"], +) + +go_library( + name = "testbench", + srcs = [ + "connections.go", + "dut.go", + "dut_client.go", + "layers.go", + "rawsockets.go", + ], + deps = [ + "//pkg/tcpip", + "//pkg/tcpip/buffer", + "//pkg/tcpip/header", + "//pkg/tcpip/seqnum", + "//pkg/usermem", + "//test/packetimpact/proto:posix_server_go_proto", + "@com_github_google_go-cmp//cmp:go_default_library", + "@com_github_google_go-cmp//cmp/cmpopts:go_default_library", + "@com_github_mohae_deepcopy//:go_default_library", + "@org_golang_google_grpc//:go_default_library", + "@org_golang_google_grpc//keepalive:go_default_library", + "@org_golang_x_sys//unix:go_default_library", + "@org_uber_go_multierr//:go_default_library", + ], +) + +go_test( + name = "testbench_test", + size = "small", + srcs = ["layers_test.go"], + library = ":testbench", + deps = [ + "//pkg/tcpip", + "@com_github_mohae_deepcopy//:go_default_library", + ], +) diff --git a/test/packetimpact/testbench/connections.go b/test/packetimpact/testbench/connections.go new file mode 100644 index 000000000..2280bd4ee --- /dev/null +++ b/test/packetimpact/testbench/connections.go @@ -0,0 +1,824 @@ +// 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 has utilities to send and receive packets and also command +// the DUT to run POSIX functions. +package testbench + +import ( + "flag" + "fmt" + "math/rand" + "net" + "testing" + "time" + + "github.com/mohae/deepcopy" + "go.uber.org/multierr" + "golang.org/x/sys/unix" + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/header" + "gvisor.dev/gvisor/pkg/tcpip/seqnum" +) + +var localIPv4 = flag.String("local_ipv4", "", "local IPv4 address for test packets") +var remoteIPv4 = flag.String("remote_ipv4", "", "remote IPv4 address for test packets") +var localIPv6 = flag.String("local_ipv6", "", "local IPv6 address for test packets") +var remoteIPv6 = flag.String("remote_ipv6", "", "remote IPv6 address for test packets") +var localMAC = flag.String("local_mac", "", "local mac address for test packets") +var remoteMAC = flag.String("remote_mac", "", "remote mac address for test packets") + +// pickPort makes a new socket and returns the socket FD and port. The domain +// should be AF_INET or AF_INET6. The caller must close the FD when done with +// the port if there is no error. +func pickPort(domain, typ int) (fd int, port uint16, err error) { + fd, err = unix.Socket(domain, typ, 0) + if err != nil { + return -1, 0, err + } + defer func() { + if err != nil { + err = multierr.Append(err, unix.Close(fd)) + } + }() + var sa unix.Sockaddr + switch domain { + case unix.AF_INET: + var sa4 unix.SockaddrInet4 + copy(sa4.Addr[:], net.ParseIP(*localIPv4).To4()) + sa = &sa4 + case unix.AF_INET6: + var sa6 unix.SockaddrInet6 + copy(sa6.Addr[:], net.ParseIP(*localIPv6).To16()) + sa = &sa6 + default: + return -1, 0, fmt.Errorf("invalid domain %d, it should be one of unix.AF_INET or unix.AF_INET6", domain) + } + if err = unix.Bind(fd, sa); err != nil { + return -1, 0, err + } + newSockAddr, err := unix.Getsockname(fd) + if err != nil { + return -1, 0, err + } + switch domain { + case unix.AF_INET: + newSockAddrInet4, ok := newSockAddr.(*unix.SockaddrInet4) + if !ok { + return -1, 0, fmt.Errorf("can't cast Getsockname result %T to SockaddrInet4", newSockAddr) + } + return fd, uint16(newSockAddrInet4.Port), nil + case unix.AF_INET6: + newSockAddrInet6, ok := newSockAddr.(*unix.SockaddrInet6) + if !ok { + return -1, 0, fmt.Errorf("can't cast Getsockname result %T to SockaddrInet6", newSockAddr) + } + return fd, uint16(newSockAddrInet6.Port), nil + default: + return -1, 0, fmt.Errorf("invalid domain %d, it should be one of unix.AF_INET or unix.AF_INET6", domain) + } +} + +// layerState stores the state of a layer of a connection. +type layerState interface { + // outgoing returns an outgoing layer to be sent in a frame. It should not + // update layerState, that is done in layerState.sent. + outgoing() Layer + + // incoming creates an expected Layer for comparing against a received Layer. + // Because the expectation can depend on values in the received Layer, it is + // an input to incoming. For example, the ACK number needs to be checked in a + // TCP packet but only if the ACK flag is set in the received packet. It + // should not update layerState, that is done in layerState.received. The + // caller takes ownership of the returned Layer. + incoming(received Layer) Layer + + // sent updates the layerState based on the Layer that was sent. The input is + // a Layer with all prev and next pointers populated so that the entire frame + // as it was sent is available. + sent(sent Layer) error + + // received updates the layerState based on a Layer that is receieved. The + // input is a Layer with all prev and next pointers populated so that the + // entire frame as it was receieved is available. + received(received Layer) error + + // close frees associated resources held by the LayerState. + close() error +} + +// etherState maintains state about an Ethernet connection. +type etherState struct { + out, in Ether +} + +var _ layerState = (*etherState)(nil) + +// newEtherState creates a new etherState. +func newEtherState(out, in Ether) (*etherState, error) { + lMAC, err := tcpip.ParseMACAddress(*localMAC) + if err != nil { + return nil, err + } + + rMAC, err := tcpip.ParseMACAddress(*remoteMAC) + if err != nil { + return nil, err + } + s := etherState{ + out: Ether{SrcAddr: &lMAC, DstAddr: &rMAC}, + in: Ether{SrcAddr: &rMAC, DstAddr: &lMAC}, + } + if err := s.out.merge(&out); err != nil { + return nil, err + } + if err := s.in.merge(&in); err != nil { + return nil, err + } + return &s, nil +} + +func (s *etherState) outgoing() Layer { + return deepcopy.Copy(&s.out).(Layer) +} + +// incoming implements layerState.incoming. +func (s *etherState) incoming(Layer) Layer { + return deepcopy.Copy(&s.in).(Layer) +} + +func (*etherState) sent(Layer) error { + return nil +} + +func (*etherState) received(Layer) error { + return nil +} + +func (*etherState) close() error { + return nil +} + +// ipv4State maintains state about an IPv4 connection. +type ipv4State struct { + out, in IPv4 +} + +var _ layerState = (*ipv4State)(nil) + +// newIPv4State creates a new ipv4State. +func newIPv4State(out, in IPv4) (*ipv4State, error) { + lIP := tcpip.Address(net.ParseIP(*localIPv4).To4()) + rIP := tcpip.Address(net.ParseIP(*remoteIPv4).To4()) + s := ipv4State{ + out: IPv4{SrcAddr: &lIP, DstAddr: &rIP}, + in: IPv4{SrcAddr: &rIP, DstAddr: &lIP}, + } + if err := s.out.merge(&out); err != nil { + return nil, err + } + if err := s.in.merge(&in); err != nil { + return nil, err + } + return &s, nil +} + +func (s *ipv4State) outgoing() Layer { + return deepcopy.Copy(&s.out).(Layer) +} + +// incoming implements layerState.incoming. +func (s *ipv4State) incoming(Layer) Layer { + return deepcopy.Copy(&s.in).(Layer) +} + +func (*ipv4State) sent(Layer) error { + return nil +} + +func (*ipv4State) received(Layer) error { + return nil +} + +func (*ipv4State) close() error { + return nil +} + +// ipv6State maintains state about an IPv6 connection. +type ipv6State struct { + out, in IPv6 +} + +var _ layerState = (*ipv6State)(nil) + +// newIPv6State creates a new ipv6State. +func newIPv6State(out, in IPv6) (*ipv6State, error) { + lIP := tcpip.Address(net.ParseIP(*localIPv6).To16()) + rIP := tcpip.Address(net.ParseIP(*remoteIPv6).To16()) + s := ipv6State{ + out: IPv6{SrcAddr: &lIP, DstAddr: &rIP}, + in: IPv6{SrcAddr: &rIP, DstAddr: &lIP}, + } + if err := s.out.merge(&out); err != nil { + return nil, err + } + if err := s.in.merge(&in); err != nil { + return nil, err + } + return &s, nil +} + +// outgoing returns an outgoing layer to be sent in a frame. +func (s *ipv6State) outgoing() Layer { + return deepcopy.Copy(&s.out).(Layer) +} + +func (s *ipv6State) incoming(Layer) Layer { + return deepcopy.Copy(&s.in).(Layer) +} + +func (s *ipv6State) sent(Layer) error { + // Nothing to do. + return nil +} + +func (s *ipv6State) received(Layer) error { + // Nothing to do. + return nil +} + +// close cleans up any resources held. +func (s *ipv6State) close() error { + return nil +} + +// tcpState maintains state about a TCP connection. +type tcpState struct { + out, in TCP + localSeqNum, remoteSeqNum *seqnum.Value + synAck *TCP + portPickerFD int + finSent bool +} + +var _ layerState = (*tcpState)(nil) + +// SeqNumValue is a helper routine that allocates a new seqnum.Value value to +// store v and returns a pointer to it. +func SeqNumValue(v seqnum.Value) *seqnum.Value { + return &v +} + +// newTCPState creates a new TCPState. +func newTCPState(domain int, out, in TCP) (*tcpState, error) { + portPickerFD, localPort, err := pickPort(domain, unix.SOCK_STREAM) + if err != nil { + return nil, err + } + s := tcpState{ + out: TCP{SrcPort: &localPort}, + in: TCP{DstPort: &localPort}, + localSeqNum: SeqNumValue(seqnum.Value(rand.Uint32())), + portPickerFD: portPickerFD, + finSent: false, + } + if err := s.out.merge(&out); err != nil { + return nil, err + } + if err := s.in.merge(&in); err != nil { + return nil, err + } + return &s, nil +} + +func (s *tcpState) outgoing() Layer { + newOutgoing := deepcopy.Copy(s.out).(TCP) + if s.localSeqNum != nil { + newOutgoing.SeqNum = Uint32(uint32(*s.localSeqNum)) + } + if s.remoteSeqNum != nil { + newOutgoing.AckNum = Uint32(uint32(*s.remoteSeqNum)) + } + return &newOutgoing +} + +// incoming implements layerState.incoming. +func (s *tcpState) incoming(received Layer) Layer { + tcpReceived, ok := received.(*TCP) + if !ok { + return nil + } + newIn := deepcopy.Copy(s.in).(TCP) + if s.remoteSeqNum != nil { + newIn.SeqNum = Uint32(uint32(*s.remoteSeqNum)) + } + if s.localSeqNum != nil && (*tcpReceived.Flags&header.TCPFlagAck) != 0 { + // The caller didn't specify an AckNum so we'll expect the calculated one, + // but only if the ACK flag is set because the AckNum is not valid in a + // header if ACK is not set. + newIn.AckNum = Uint32(uint32(*s.localSeqNum)) + } + return &newIn +} + +func (s *tcpState) sent(sent Layer) error { + tcp, ok := sent.(*TCP) + if !ok { + return fmt.Errorf("can't update tcpState with %T Layer", sent) + } + if !s.finSent { + // update localSeqNum by the payload only when FIN is not yet sent by us + for current := tcp.next(); current != nil; current = current.next() { + s.localSeqNum.UpdateForward(seqnum.Size(current.length())) + } + } + if tcp.Flags != nil && *tcp.Flags&(header.TCPFlagSyn|header.TCPFlagFin) != 0 { + s.localSeqNum.UpdateForward(1) + } + if *tcp.Flags&(header.TCPFlagFin) != 0 { + s.finSent = true + } + return nil +} + +func (s *tcpState) received(l Layer) error { + tcp, ok := l.(*TCP) + if !ok { + return fmt.Errorf("can't update tcpState with %T Layer", l) + } + s.remoteSeqNum = SeqNumValue(seqnum.Value(*tcp.SeqNum)) + if *tcp.Flags&(header.TCPFlagSyn|header.TCPFlagFin) != 0 { + s.remoteSeqNum.UpdateForward(1) + } + for current := tcp.next(); current != nil; current = current.next() { + s.remoteSeqNum.UpdateForward(seqnum.Size(current.length())) + } + return nil +} + +// close frees the port associated with this connection. +func (s *tcpState) close() error { + if err := unix.Close(s.portPickerFD); err != nil { + return err + } + s.portPickerFD = -1 + return nil +} + +// udpState maintains state about a UDP connection. +type udpState struct { + out, in UDP + portPickerFD int +} + +var _ layerState = (*udpState)(nil) + +// newUDPState creates a new udpState. +func newUDPState(domain int, out, in UDP) (*udpState, error) { + portPickerFD, localPort, err := pickPort(domain, unix.SOCK_DGRAM) + if err != nil { + return nil, err + } + s := udpState{ + out: UDP{SrcPort: &localPort}, + in: UDP{DstPort: &localPort}, + portPickerFD: portPickerFD, + } + if err := s.out.merge(&out); err != nil { + return nil, err + } + if err := s.in.merge(&in); err != nil { + return nil, err + } + return &s, nil +} + +func (s *udpState) outgoing() Layer { + return deepcopy.Copy(&s.out).(Layer) +} + +// incoming implements layerState.incoming. +func (s *udpState) incoming(Layer) Layer { + return deepcopy.Copy(&s.in).(Layer) +} + +func (*udpState) sent(l Layer) error { + return nil +} + +func (*udpState) received(l Layer) error { + return nil +} + +// close frees the port associated with this connection. +func (s *udpState) close() error { + if err := unix.Close(s.portPickerFD); err != nil { + return err + } + s.portPickerFD = -1 + return nil +} + +// Connection holds a collection of layer states for maintaining a connection +// along with sockets for sniffer and injecting packets. +type Connection struct { + layerStates []layerState + injector Injector + sniffer Sniffer + t *testing.T +} + +// Returns the default incoming frame against which to match. If received is +// longer than layerStates then that may still count as a match. The reverse is +// never a match and nil is returned. +func (conn *Connection) incoming(received Layers) Layers { + if len(received) < len(conn.layerStates) { + return nil + } + in := Layers{} + for i, s := range conn.layerStates { + toMatch := s.incoming(received[i]) + if toMatch == nil { + return nil + } + in = append(in, toMatch) + } + return in +} + +func (conn *Connection) match(override, received Layers) bool { + toMatch := conn.incoming(received) + if toMatch == nil { + return false // Not enough layers in gotLayers for matching. + } + if err := toMatch.merge(override); err != nil { + return false // Failing to merge is not matching. + } + return toMatch.match(received) +} + +// Close frees associated resources held by the Connection. +func (conn *Connection) Close() { + errs := multierr.Combine(conn.sniffer.close(), conn.injector.close()) + for _, s := range conn.layerStates { + if err := s.close(); err != nil { + errs = multierr.Append(errs, fmt.Errorf("unable to close %+v: %s", s, err)) + } + } + if errs != nil { + conn.t.Fatalf("unable to close %+v: %s", conn, errs) + } +} + +// CreateFrame builds a frame for the connection with layer overriding defaults +// of the innermost layer and additionalLayers added after it. +func (conn *Connection) CreateFrame(layer Layer, additionalLayers ...Layer) Layers { + var layersToSend Layers + for _, s := range conn.layerStates { + layersToSend = append(layersToSend, s.outgoing()) + } + if err := layersToSend[len(layersToSend)-1].merge(layer); err != nil { + conn.t.Fatalf("can't merge %+v into %+v: %s", layer, layersToSend[len(layersToSend)-1], err) + } + layersToSend = append(layersToSend, additionalLayers...) + return layersToSend +} + +// SendFrame sends a frame on the wire and updates the state of all layers. +func (conn *Connection) SendFrame(frame Layers) { + outBytes, err := frame.ToBytes() + if err != nil { + conn.t.Fatalf("can't build outgoing TCP packet: %s", err) + } + conn.injector.Send(outBytes) + + // frame might have nil values where the caller wanted to use default values. + // sentFrame will have no nil values in it because it comes from parsing the + // bytes that were actually sent. + sentFrame := parse(parseEther, outBytes) + // Update the state of each layer based on what was sent. + for i, s := range conn.layerStates { + if err := s.sent(sentFrame[i]); err != nil { + conn.t.Fatalf("Unable to update the state of %+v with %s: %s", s, sentFrame[i], err) + } + } +} + +// Send a packet with reasonable defaults. Potentially override the final layer +// in the connection with the provided layer and add additionLayers. +func (conn *Connection) Send(layer Layer, additionalLayers ...Layer) { + conn.SendFrame(conn.CreateFrame(layer, additionalLayers...)) +} + +// recvFrame gets the next successfully parsed frame (of type Layers) within the +// timeout provided. If no parsable frame arrives before the timeout, it returns +// nil. +func (conn *Connection) recvFrame(timeout time.Duration) Layers { + if timeout <= 0 { + return nil + } + b := conn.sniffer.Recv(timeout) + if b == nil { + return nil + } + return parse(parseEther, b) +} + +// layersError stores the Layers that we got and the Layers that we wanted to +// match. +type layersError struct { + got, want Layers +} + +func (e *layersError) Error() string { + return e.got.diff(e.want) +} + +// Expect a frame with the final layerStates layer matching the provided Layer +// within the timeout specified. If it doesn't arrive in time, it returns nil. +func (conn *Connection) Expect(layer Layer, timeout time.Duration) (Layer, error) { + // Make a frame that will ignore all but the final layer. + layers := make([]Layer, len(conn.layerStates)) + layers[len(layers)-1] = layer + + gotFrame, err := conn.ExpectFrame(layers, timeout) + if err != nil { + return nil, err + } + if len(conn.layerStates)-1 < len(gotFrame) { + return gotFrame[len(conn.layerStates)-1], nil + } + conn.t.Fatal("the received frame should be at least as long as the expected layers") + panic("unreachable") +} + +// ExpectFrame expects a frame that matches the provided Layers within the +// timeout specified. If one arrives in time, the Layers is returned without an +// error. If it doesn't arrive in time, it returns nil and error is non-nil. +func (conn *Connection) ExpectFrame(layers Layers, timeout time.Duration) (Layers, error) { + deadline := time.Now().Add(timeout) + var errs error + for { + var gotLayers Layers + if timeout = time.Until(deadline); timeout > 0 { + gotLayers = conn.recvFrame(timeout) + } + if gotLayers == nil { + if errs == nil { + return nil, fmt.Errorf("got no frames matching %v during %s", layers, timeout) + } + return nil, fmt.Errorf("got no frames matching %v during %s: got %w", layers, timeout, errs) + } + if conn.match(layers, gotLayers) { + for i, s := range conn.layerStates { + if err := s.received(gotLayers[i]); err != nil { + conn.t.Fatal(err) + } + } + return gotLayers, nil + } + errs = multierr.Combine(errs, &layersError{got: gotLayers, want: conn.incoming(gotLayers)}) + } +} + +// Drain drains the sniffer's receive buffer by receiving packets until there's +// nothing else to receive. +func (conn *Connection) Drain() { + conn.sniffer.Drain() +} + +// TCPIPv4 maintains the state for all the layers in a TCP/IPv4 connection. +type TCPIPv4 Connection + +// NewTCPIPv4 creates a new TCPIPv4 connection with reasonable defaults. +func NewTCPIPv4(t *testing.T, outgoingTCP, incomingTCP TCP) TCPIPv4 { + etherState, err := newEtherState(Ether{}, Ether{}) + if err != nil { + t.Fatalf("can't make etherState: %s", err) + } + ipv4State, err := newIPv4State(IPv4{}, IPv4{}) + if err != nil { + t.Fatalf("can't make ipv4State: %s", err) + } + tcpState, err := newTCPState(unix.AF_INET, outgoingTCP, incomingTCP) + if err != nil { + t.Fatalf("can't make tcpState: %s", err) + } + injector, err := NewInjector(t) + if err != nil { + t.Fatalf("can't make injector: %s", err) + } + sniffer, err := NewSniffer(t) + if err != nil { + t.Fatalf("can't make sniffer: %s", err) + } + + return TCPIPv4{ + layerStates: []layerState{etherState, ipv4State, tcpState}, + injector: injector, + sniffer: sniffer, + t: t, + } +} + +// Handshake performs a TCP 3-way handshake. The input Connection should have a +// final TCP Layer. +func (conn *TCPIPv4) Handshake() { + // Send the SYN. + conn.Send(TCP{Flags: Uint8(header.TCPFlagSyn)}) + + // Wait for the SYN-ACK. + synAck, err := conn.Expect(TCP{Flags: Uint8(header.TCPFlagSyn | header.TCPFlagAck)}, time.Second) + if synAck == nil { + conn.t.Fatalf("didn't get synack during handshake: %s", err) + } + conn.layerStates[len(conn.layerStates)-1].(*tcpState).synAck = synAck + + // Send an ACK. + conn.Send(TCP{Flags: Uint8(header.TCPFlagAck)}) +} + +// ExpectData is a convenient method that expects a Layer and the Layer after +// it. If it doens't arrive in time, it returns nil. +func (conn *TCPIPv4) ExpectData(tcp *TCP, payload *Payload, timeout time.Duration) (Layers, error) { + expected := make([]Layer, len(conn.layerStates)) + expected[len(expected)-1] = tcp + if payload != nil { + expected = append(expected, payload) + } + return (*Connection)(conn).ExpectFrame(expected, timeout) +} + +// Send a packet with reasonable defaults. Potentially override the TCP layer in +// the connection with the provided layer and add additionLayers. +func (conn *TCPIPv4) Send(tcp TCP, additionalLayers ...Layer) { + (*Connection)(conn).Send(&tcp, additionalLayers...) +} + +// Close frees associated resources held by the TCPIPv4 connection. +func (conn *TCPIPv4) Close() { + (*Connection)(conn).Close() +} + +// Expect a frame with the TCP layer matching the provided TCP within the +// timeout specified. If it doesn't arrive in time, it returns nil. +func (conn *TCPIPv4) Expect(tcp TCP, timeout time.Duration) (*TCP, error) { + layer, err := (*Connection)(conn).Expect(&tcp, timeout) + if layer == nil { + return nil, err + } + gotTCP, ok := layer.(*TCP) + if !ok { + conn.t.Fatalf("expected %s to be TCP", layer) + } + return gotTCP, err +} + +func (conn *TCPIPv4) state() *tcpState { + state, ok := conn.layerStates[len(conn.layerStates)-1].(*tcpState) + if !ok { + conn.t.Fatalf("expected final state of %v to be tcpState", conn.layerStates) + } + return state +} + +// RemoteSeqNum returns the next expected sequence number from the DUT. +func (conn *TCPIPv4) RemoteSeqNum() *seqnum.Value { + return conn.state().remoteSeqNum +} + +// LocalSeqNum returns the next sequence number to send from the testbench. +func (conn *TCPIPv4) LocalSeqNum() *seqnum.Value { + return conn.state().localSeqNum +} + +// SynAck returns the SynAck that was part of the handshake. +func (conn *TCPIPv4) SynAck() *TCP { + return conn.state().synAck +} + +// IPv6Conn maintains the state for all the layers in a IPv6 connection. +type IPv6Conn Connection + +// NewIPv6Conn creates a new IPv6Conn connection with reasonable defaults. +func NewIPv6Conn(t *testing.T, outgoingIPv6, incomingIPv6 IPv6) IPv6Conn { + etherState, err := newEtherState(Ether{}, Ether{}) + if err != nil { + t.Fatalf("can't make EtherState: %s", err) + } + ipv6State, err := newIPv6State(outgoingIPv6, incomingIPv6) + if err != nil { + t.Fatalf("can't make IPv6State: %s", err) + } + + injector, err := NewInjector(t) + if err != nil { + t.Fatalf("can't make injector: %s", err) + } + sniffer, err := NewSniffer(t) + if err != nil { + t.Fatalf("can't make sniffer: %s", err) + } + + return IPv6Conn{ + layerStates: []layerState{etherState, ipv6State}, + injector: injector, + sniffer: sniffer, + t: t, + } +} + +// SendFrame sends a frame on the wire and updates the state of all layers. +func (conn *IPv6Conn) SendFrame(frame Layers) { + (*Connection)(conn).SendFrame(frame) +} + +// CreateFrame builds a frame for the connection with ipv6 overriding the ipv6 +// layer defaults and additionalLayers added after it. +func (conn *IPv6Conn) CreateFrame(ipv6 IPv6, additionalLayers ...Layer) Layers { + return (*Connection)(conn).CreateFrame(&ipv6, additionalLayers...) +} + +// Close to clean up any resources held. +func (conn *IPv6Conn) Close() { + (*Connection)(conn).Close() +} + +// ExpectFrame expects a frame that matches the provided Layers within the +// timeout specified. If it doesn't arrive in time, it returns nil. +func (conn *IPv6Conn) ExpectFrame(frame Layers, timeout time.Duration) (Layers, error) { + return (*Connection)(conn).ExpectFrame(frame, timeout) +} + +// Drain drains the sniffer's receive buffer by receiving packets until there's +// nothing else to receive. +func (conn *TCPIPv4) Drain() { + conn.sniffer.Drain() +} + +// UDPIPv4 maintains the state for all the layers in a UDP/IPv4 connection. +type UDPIPv4 Connection + +// NewUDPIPv4 creates a new UDPIPv4 connection with reasonable defaults. +func NewUDPIPv4(t *testing.T, outgoingUDP, incomingUDP UDP) UDPIPv4 { + etherState, err := newEtherState(Ether{}, Ether{}) + if err != nil { + t.Fatalf("can't make etherState: %s", err) + } + ipv4State, err := newIPv4State(IPv4{}, IPv4{}) + if err != nil { + t.Fatalf("can't make ipv4State: %s", err) + } + tcpState, err := newUDPState(unix.AF_INET, outgoingUDP, incomingUDP) + if err != nil { + t.Fatalf("can't make udpState: %s", err) + } + injector, err := NewInjector(t) + if err != nil { + t.Fatalf("can't make injector: %s", err) + } + sniffer, err := NewSniffer(t) + if err != nil { + t.Fatalf("can't make sniffer: %s", err) + } + + return UDPIPv4{ + layerStates: []layerState{etherState, ipv4State, tcpState}, + injector: injector, + sniffer: sniffer, + t: t, + } +} + +// CreateFrame builds a frame for the connection with layer overriding defaults +// of the innermost layer and additionalLayers added after it. +func (conn *UDPIPv4) CreateFrame(layer Layer, additionalLayers ...Layer) Layers { + return (*Connection)(conn).CreateFrame(layer, additionalLayers...) +} + +// SendFrame sends a frame on the wire and updates the state of all layers. +func (conn *UDPIPv4) SendFrame(frame Layers) { + (*Connection)(conn).SendFrame(frame) +} + +// Close frees associated resources held by the UDPIPv4 connection. +func (conn *UDPIPv4) Close() { + (*Connection)(conn).Close() +} + +// Drain drains the sniffer's receive buffer by receiving packets until there's +// nothing else to receive. +func (conn *UDPIPv4) Drain() { + conn.sniffer.Drain() +} diff --git a/test/packetimpact/testbench/dut.go b/test/packetimpact/testbench/dut.go new file mode 100644 index 000000000..3f340c6bc --- /dev/null +++ b/test/packetimpact/testbench/dut.go @@ -0,0 +1,473 @@ +// 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 ( + "context" + "flag" + "net" + "strconv" + "syscall" + "testing" + "time" + + pb "gvisor.dev/gvisor/test/packetimpact/proto/posix_server_go_proto" + + "golang.org/x/sys/unix" + "google.golang.org/grpc" + "google.golang.org/grpc/keepalive" +) + +var ( + posixServerIP = flag.String("posix_server_ip", "", "ip address to listen to for UDP commands") + posixServerPort = flag.Int("posix_server_port", 40000, "port to listen to for UDP commands") + rpcTimeout = flag.Duration("rpc_timeout", 100*time.Millisecond, "gRPC timeout") + rpcKeepalive = flag.Duration("rpc_keepalive", 10*time.Second, "gRPC keepalive") +) + +// DUT communicates with the DUT to force it to make POSIX calls. +type DUT struct { + t *testing.T + conn *grpc.ClientConn + posixServer PosixClient +} + +// NewDUT creates a new connection with the DUT over gRPC. +func NewDUT(t *testing.T) DUT { + flag.Parse() + posixServerAddress := *posixServerIP + ":" + strconv.Itoa(*posixServerPort) + conn, err := grpc.Dial(posixServerAddress, grpc.WithInsecure(), grpc.WithKeepaliveParams(keepalive.ClientParameters{Timeout: *rpcKeepalive})) + if err != nil { + t.Fatalf("failed to grpc.Dial(%s): %s", posixServerAddress, err) + } + posixServer := NewPosixClient(conn) + return DUT{ + t: t, + conn: conn, + posixServer: posixServer, + } +} + +// TearDown closes the underlying connection. +func (dut *DUT) TearDown() { + dut.conn.Close() +} + +func (dut *DUT) sockaddrToProto(sa unix.Sockaddr) *pb.Sockaddr { + dut.t.Helper() + switch s := sa.(type) { + case *unix.SockaddrInet4: + return &pb.Sockaddr{ + Sockaddr: &pb.Sockaddr_In{ + In: &pb.SockaddrIn{ + Family: unix.AF_INET, + Port: uint32(s.Port), + Addr: s.Addr[:], + }, + }, + } + case *unix.SockaddrInet6: + return &pb.Sockaddr{ + Sockaddr: &pb.Sockaddr_In6{ + In6: &pb.SockaddrIn6{ + Family: unix.AF_INET6, + Port: uint32(s.Port), + Flowinfo: 0, + ScopeId: s.ZoneId, + Addr: s.Addr[:], + }, + }, + } + } + dut.t.Fatalf("can't parse Sockaddr: %+v", sa) + return nil +} + +func (dut *DUT) protoToSockaddr(sa *pb.Sockaddr) unix.Sockaddr { + dut.t.Helper() + switch s := sa.Sockaddr.(type) { + case *pb.Sockaddr_In: + ret := unix.SockaddrInet4{ + Port: int(s.In.GetPort()), + } + copy(ret.Addr[:], s.In.GetAddr()) + return &ret + case *pb.Sockaddr_In6: + ret := unix.SockaddrInet6{ + Port: int(s.In6.GetPort()), + ZoneId: s.In6.GetScopeId(), + } + copy(ret.Addr[:], s.In6.GetAddr()) + } + dut.t.Fatalf("can't parse Sockaddr: %+v", sa) + return nil +} + +// CreateBoundSocket makes a new socket on the DUT, with type typ and protocol +// proto, and bound to the IP address addr. Returns the new file descriptor and +// the port that was selected on the DUT. +func (dut *DUT) CreateBoundSocket(typ, proto int32, addr net.IP) (int32, uint16) { + dut.t.Helper() + var fd int32 + if addr.To4() != nil { + fd = dut.Socket(unix.AF_INET, typ, proto) + sa := unix.SockaddrInet4{} + copy(sa.Addr[:], addr.To4()) + dut.Bind(fd, &sa) + } else if addr.To16() != nil { + fd = dut.Socket(unix.AF_INET6, typ, proto) + sa := unix.SockaddrInet6{} + copy(sa.Addr[:], addr.To16()) + dut.Bind(fd, &sa) + } else { + dut.t.Fatalf("unknown ip addr type for remoteIP") + } + sa := dut.GetSockName(fd) + var port int + switch s := sa.(type) { + case *unix.SockaddrInet4: + port = s.Port + case *unix.SockaddrInet6: + port = s.Port + default: + dut.t.Fatalf("unknown sockaddr type from getsockname: %t", sa) + } + return fd, uint16(port) +} + +// CreateListener makes a new TCP connection. If it fails, the test ends. +func (dut *DUT) CreateListener(typ, proto, backlog int32) (int32, uint16) { + fd, remotePort := dut.CreateBoundSocket(typ, proto, net.ParseIP(*remoteIPv4)) + dut.Listen(fd, backlog) + return fd, remotePort +} + +// All the functions that make gRPC calls to the Posix service are below, sorted +// alphabetically. + +// Accept calls accept on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is needed, use +// AcceptWithErrno. +func (dut *DUT) Accept(sockfd int32) (int32, unix.Sockaddr) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + fd, sa, err := dut.AcceptWithErrno(ctx, sockfd) + if fd < 0 { + dut.t.Fatalf("failed to accept: %s", err) + } + return fd, sa +} + +// AcceptWithErrno calls accept on the DUT. +func (dut *DUT) AcceptWithErrno(ctx context.Context, sockfd int32) (int32, unix.Sockaddr, error) { + dut.t.Helper() + req := pb.AcceptRequest{ + Sockfd: sockfd, + } + resp, err := dut.posixServer.Accept(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Accept: %s", err) + } + return resp.GetFd(), dut.protoToSockaddr(resp.GetAddr()), syscall.Errno(resp.GetErrno_()) +} + +// Bind calls bind on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is +// needed, use BindWithErrno. +func (dut *DUT) Bind(fd int32, sa unix.Sockaddr) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.BindWithErrno(ctx, fd, sa) + if ret != 0 { + dut.t.Fatalf("failed to bind socket: %s", err) + } +} + +// BindWithErrno calls bind on the DUT. +func (dut *DUT) BindWithErrno(ctx context.Context, fd int32, sa unix.Sockaddr) (int32, error) { + dut.t.Helper() + req := pb.BindRequest{ + Sockfd: fd, + Addr: dut.sockaddrToProto(sa), + } + resp, err := dut.posixServer.Bind(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Bind: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// Close calls close on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is needed, use +// CloseWithErrno. +func (dut *DUT) Close(fd int32) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.CloseWithErrno(ctx, fd) + if ret != 0 { + dut.t.Fatalf("failed to close: %s", err) + } +} + +// CloseWithErrno calls close on the DUT. +func (dut *DUT) CloseWithErrno(ctx context.Context, fd int32) (int32, error) { + dut.t.Helper() + req := pb.CloseRequest{ + Fd: fd, + } + resp, err := dut.posixServer.Close(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Close: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// GetSockName calls getsockname on the DUT and causes a fatal test failure if +// it doesn't succeed. If more control over the timeout or error handling is +// needed, use GetSockNameWithErrno. +func (dut *DUT) GetSockName(sockfd int32) unix.Sockaddr { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, sa, err := dut.GetSockNameWithErrno(ctx, sockfd) + if ret != 0 { + dut.t.Fatalf("failed to getsockname: %s", err) + } + return sa +} + +// GetSockNameWithErrno calls getsockname on the DUT. +func (dut *DUT) GetSockNameWithErrno(ctx context.Context, sockfd int32) (int32, unix.Sockaddr, error) { + dut.t.Helper() + req := pb.GetSockNameRequest{ + Sockfd: sockfd, + } + resp, err := dut.posixServer.GetSockName(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Bind: %s", err) + } + return resp.GetRet(), dut.protoToSockaddr(resp.GetAddr()), syscall.Errno(resp.GetErrno_()) +} + +// Listen calls listen on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is needed, use +// ListenWithErrno. +func (dut *DUT) Listen(sockfd, backlog int32) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.ListenWithErrno(ctx, sockfd, backlog) + if ret != 0 { + dut.t.Fatalf("failed to listen: %s", err) + } +} + +// ListenWithErrno calls listen on the DUT. +func (dut *DUT) ListenWithErrno(ctx context.Context, sockfd, backlog int32) (int32, error) { + dut.t.Helper() + req := pb.ListenRequest{ + Sockfd: sockfd, + Backlog: backlog, + } + resp, err := dut.posixServer.Listen(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Listen: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// Send calls send on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is needed, use +// SendWithErrno. +func (dut *DUT) Send(sockfd int32, buf []byte, flags int32) int32 { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.SendWithErrno(ctx, sockfd, buf, flags) + if ret == -1 { + dut.t.Fatalf("failed to send: %s", err) + } + return ret +} + +// SendWithErrno calls send on the DUT. +func (dut *DUT) SendWithErrno(ctx context.Context, sockfd int32, buf []byte, flags int32) (int32, error) { + dut.t.Helper() + req := pb.SendRequest{ + Sockfd: sockfd, + Buf: buf, + Flags: flags, + } + resp, err := dut.posixServer.Send(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Send: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// SetSockOpt calls setsockopt on the DUT and causes a fatal test failure if it +// doesn't succeed. If more control over the timeout or error handling is +// needed, use SetSockOptWithErrno. Because endianess and the width of values +// might differ between the testbench and DUT architectures, prefer to use a +// more specific SetSockOptXxx function. +func (dut *DUT) SetSockOpt(sockfd, level, optname int32, optval []byte) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.SetSockOptWithErrno(ctx, sockfd, level, optname, optval) + if ret != 0 { + dut.t.Fatalf("failed to SetSockOpt: %s", err) + } +} + +// SetSockOptWithErrno calls setsockopt on the DUT. Because endianess and the +// width of values might differ between the testbench and DUT architectures, +// prefer to use a more specific SetSockOptXxxWithErrno function. +func (dut *DUT) SetSockOptWithErrno(ctx context.Context, sockfd, level, optname int32, optval []byte) (int32, error) { + dut.t.Helper() + req := pb.SetSockOptRequest{ + Sockfd: sockfd, + Level: level, + Optname: optname, + Optval: optval, + } + resp, err := dut.posixServer.SetSockOpt(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call SetSockOpt: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// SetSockOptInt calls setsockopt on the DUT and causes a fatal test failure +// if it doesn't succeed. If more control over the int optval or error handling +// is needed, use SetSockOptIntWithErrno. +func (dut *DUT) SetSockOptInt(sockfd, level, optname, optval int32) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.SetSockOptIntWithErrno(ctx, sockfd, level, optname, optval) + if ret != 0 { + dut.t.Fatalf("failed to SetSockOptInt: %s", err) + } +} + +// SetSockOptIntWithErrno calls setsockopt with an integer optval. +func (dut *DUT) SetSockOptIntWithErrno(ctx context.Context, sockfd, level, optname, optval int32) (int32, error) { + dut.t.Helper() + req := pb.SetSockOptIntRequest{ + Sockfd: sockfd, + Level: level, + Optname: optname, + Intval: optval, + } + resp, err := dut.posixServer.SetSockOptInt(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call SetSockOptInt: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// SetSockOptTimeval calls setsockopt on the DUT and causes a fatal test failure +// if it doesn't succeed. If more control over the timeout or error handling is +// needed, use SetSockOptTimevalWithErrno. +func (dut *DUT) SetSockOptTimeval(sockfd, level, optname int32, tv *unix.Timeval) { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, err := dut.SetSockOptTimevalWithErrno(ctx, sockfd, level, optname, tv) + if ret != 0 { + dut.t.Fatalf("failed to SetSockOptTimeval: %s", err) + } +} + +// SetSockOptTimevalWithErrno calls setsockopt with the timeval converted to +// bytes. +func (dut *DUT) SetSockOptTimevalWithErrno(ctx context.Context, sockfd, level, optname int32, tv *unix.Timeval) (int32, error) { + dut.t.Helper() + timeval := pb.Timeval{ + Seconds: int64(tv.Sec), + Microseconds: int64(tv.Usec), + } + req := pb.SetSockOptTimevalRequest{ + Sockfd: sockfd, + Level: level, + Optname: optname, + Timeval: &timeval, + } + resp, err := dut.posixServer.SetSockOptTimeval(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call SetSockOptTimeval: %s", err) + } + return resp.GetRet(), syscall.Errno(resp.GetErrno_()) +} + +// Socket calls socket on the DUT and returns the file descriptor. If socket +// fails on the DUT, the test ends. +func (dut *DUT) Socket(domain, typ, proto int32) int32 { + dut.t.Helper() + fd, err := dut.SocketWithErrno(domain, typ, proto) + if fd < 0 { + dut.t.Fatalf("failed to create socket: %s", err) + } + return fd +} + +// SocketWithErrno calls socket on the DUT and returns the fd and errno. +func (dut *DUT) SocketWithErrno(domain, typ, proto int32) (int32, error) { + dut.t.Helper() + req := pb.SocketRequest{ + Domain: domain, + Type: typ, + Protocol: proto, + } + ctx := context.Background() + resp, err := dut.posixServer.Socket(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Socket: %s", err) + } + return resp.GetFd(), syscall.Errno(resp.GetErrno_()) +} + +// Recv calls recv on the DUT and causes a fatal test failure if it doesn't +// succeed. If more control over the timeout or error handling is needed, use +// RecvWithErrno. +func (dut *DUT) Recv(sockfd, len, flags int32) []byte { + dut.t.Helper() + ctx, cancel := context.WithTimeout(context.Background(), *rpcTimeout) + defer cancel() + ret, buf, err := dut.RecvWithErrno(ctx, sockfd, len, flags) + if ret == -1 { + dut.t.Fatalf("failed to recv: %s", err) + } + return buf +} + +// RecvWithErrno calls recv on the DUT. +func (dut *DUT) RecvWithErrno(ctx context.Context, sockfd, len, flags int32) (int32, []byte, error) { + dut.t.Helper() + req := pb.RecvRequest{ + Sockfd: sockfd, + Len: len, + Flags: flags, + } + resp, err := dut.posixServer.Recv(ctx, &req) + if err != nil { + dut.t.Fatalf("failed to call Recv: %s", err) + } + return resp.GetRet(), resp.GetBuf(), syscall.Errno(resp.GetErrno_()) +} diff --git a/test/packetimpact/testbench/dut_client.go b/test/packetimpact/testbench/dut_client.go new file mode 100644 index 000000000..b130a33a2 --- /dev/null +++ b/test/packetimpact/testbench/dut_client.go @@ -0,0 +1,28 @@ +// 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 ( + "google.golang.org/grpc" + pb "gvisor.dev/gvisor/test/packetimpact/proto/posix_server_go_proto" +) + +// PosixClient is a gRPC client for the Posix service. +type PosixClient pb.PosixClient + +// NewPosixClient makes a new gRPC client for the Posix service. +func NewPosixClient(c grpc.ClientConnInterface) PosixClient { + return pb.NewPosixClient(c) +} diff --git a/test/packetimpact/testbench/layers.go b/test/packetimpact/testbench/layers.go new file mode 100644 index 000000000..817f5c261 --- /dev/null +++ b/test/packetimpact/testbench/layers.go @@ -0,0 +1,1157 @@ +// 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/hex" + "fmt" + "reflect" + "strings" + + "github.com/google/go-cmp/cmp" + "github.com/google/go-cmp/cmp/cmpopts" + "go.uber.org/multierr" + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" + "gvisor.dev/gvisor/pkg/tcpip/header" +) + +// Layer is the interface that all encapsulations must implement. +// +// A Layer is an encapsulation in a packet, such as TCP, IPv4, IPv6, etc. A +// Layer contains all the fields of the encapsulation. Each field is a pointer +// and may be nil. +type Layer interface { + fmt.Stringer + + // ToBytes converts the Layer into bytes. In places where the Layer's field + // isn't nil, the value that is pointed to is used. When the field is nil, a + // reasonable default for the Layer is used. For example, "64" for IPv4 TTL + // and a calculated checksum for TCP or IP. Some layers require information + // from the previous or next layers in order to compute a default, such as + // TCP's checksum or Ethernet's type, so each Layer has a doubly-linked list + // to the layer's neighbors. + ToBytes() ([]byte, error) + + // match checks if the current Layer matches the provided Layer. If either + // Layer has a nil in a given field, that field is considered matching. + // Otherwise, the values pointed to by the fields must match. The LayerBase is + // ignored. + match(Layer) bool + + // length in bytes of the current encapsulation + length() int + + // next gets a pointer to the encapsulated Layer. + next() Layer + + // prev gets a pointer to the Layer encapsulating this one. + prev() Layer + + // setNext sets the pointer to the encapsulated Layer. + setNext(Layer) + + // setPrev sets the pointer to the Layer encapsulating this one. + setPrev(Layer) + + // merge overrides the values in the interface with the provided values. + merge(Layer) error +} + +// LayerBase is the common elements of all layers. +type LayerBase struct { + nextLayer Layer + prevLayer Layer +} + +func (lb *LayerBase) next() Layer { + return lb.nextLayer +} + +func (lb *LayerBase) prev() Layer { + return lb.prevLayer +} + +func (lb *LayerBase) setNext(l Layer) { + lb.nextLayer = l +} + +func (lb *LayerBase) setPrev(l Layer) { + lb.prevLayer = l +} + +// equalLayer compares that two Layer structs match while ignoring field in +// which either input has a nil and also ignoring the LayerBase of the inputs. +func equalLayer(x, y Layer) bool { + if x == nil || y == nil { + return true + } + // opt ignores comparison pairs where either of the inputs is a nil. + opt := cmp.FilterValues(func(x, y interface{}) bool { + for _, l := range []interface{}{x, y} { + v := reflect.ValueOf(l) + if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Slice) && v.IsNil() { + return true + } + } + return false + }, cmp.Ignore()) + return cmp.Equal(x, y, opt, cmpopts.IgnoreTypes(LayerBase{})) +} + +// mergeLayer merges y into x. Any fields for which y has a non-nil value, that +// value overwrite the corresponding fields in x. +func mergeLayer(x, y Layer) error { + if y == nil { + return nil + } + if reflect.TypeOf(x) != reflect.TypeOf(y) { + return fmt.Errorf("can't merge %T into %T", y, x) + } + vx := reflect.ValueOf(x).Elem() + vy := reflect.ValueOf(y).Elem() + t := vy.Type() + for i := 0; i < vy.NumField(); i++ { + t := t.Field(i) + if t.Anonymous { + // Ignore the LayerBase in the Layer struct. + continue + } + v := vy.Field(i) + if v.IsNil() { + continue + } + vx.Field(i).Set(v) + } + return nil +} + +func stringLayer(l Layer) string { + v := reflect.ValueOf(l).Elem() + t := v.Type() + var ret []string + for i := 0; i < v.NumField(); i++ { + t := t.Field(i) + if t.Anonymous { + // Ignore the LayerBase in the Layer struct. + continue + } + v := v.Field(i) + if v.IsNil() { + continue + } + v = reflect.Indirect(v) + if v.Kind() == reflect.Slice && v.Type().Elem().Kind() == reflect.Uint8 { + ret = append(ret, fmt.Sprintf("%s:\n%v", t.Name, hex.Dump(v.Bytes()))) + } else { + ret = append(ret, fmt.Sprintf("%s:%v", t.Name, v)) + } + } + return fmt.Sprintf("&%s{%s}", t, strings.Join(ret, " ")) +} + +// Ether can construct and match an ethernet encapsulation. +type Ether struct { + LayerBase + SrcAddr *tcpip.LinkAddress + DstAddr *tcpip.LinkAddress + Type *tcpip.NetworkProtocolNumber +} + +func (l *Ether) String() string { + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *Ether) ToBytes() ([]byte, error) { + b := make([]byte, header.EthernetMinimumSize) + h := header.Ethernet(b) + fields := &header.EthernetFields{} + if l.SrcAddr != nil { + fields.SrcAddr = *l.SrcAddr + } + if l.DstAddr != nil { + fields.DstAddr = *l.DstAddr + } + if l.Type != nil { + fields.Type = *l.Type + } else { + switch n := l.next().(type) { + case *IPv4: + fields.Type = header.IPv4ProtocolNumber + case *IPv6: + fields.Type = header.IPv6ProtocolNumber + default: + return nil, fmt.Errorf("ethernet header's next layer is unrecognized: %#v", n) + } + } + h.Encode(fields) + return h, nil +} + +// LinkAddress is a helper routine that allocates a new tcpip.LinkAddress value +// to store v and returns a pointer to it. +func LinkAddress(v tcpip.LinkAddress) *tcpip.LinkAddress { + return &v +} + +// NetworkProtocolNumber is a helper routine that allocates a new +// tcpip.NetworkProtocolNumber value to store v and returns a pointer to it. +func NetworkProtocolNumber(v tcpip.NetworkProtocolNumber) *tcpip.NetworkProtocolNumber { + return &v +} + +// layerParser parses the input bytes and returns a Layer along with the next +// layerParser to run. If there is no more parsing to do, the returned +// layerParser is nil. +type layerParser func([]byte) (Layer, layerParser) + +// parse parses bytes starting with the first layerParser and using successive +// layerParsers until all the bytes are parsed. +func parse(parser layerParser, b []byte) Layers { + var layers Layers + for { + var layer Layer + layer, parser = parser(b) + layers = append(layers, layer) + if parser == nil { + break + } + b = b[layer.length():] + } + layers.linkLayers() + return layers +} + +// parseEther parses the bytes assuming that they start with an ethernet header +// and continues parsing further encapsulations. +func parseEther(b []byte) (Layer, layerParser) { + h := header.Ethernet(b) + ether := Ether{ + SrcAddr: LinkAddress(h.SourceAddress()), + DstAddr: LinkAddress(h.DestinationAddress()), + Type: NetworkProtocolNumber(h.Type()), + } + var nextParser layerParser + switch h.Type() { + case header.IPv4ProtocolNumber: + nextParser = parseIPv4 + case header.IPv6ProtocolNumber: + nextParser = parseIPv6 + default: + // Assume that the rest is a payload. + nextParser = parsePayload + } + return ðer, nextParser +} + +func (l *Ether) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *Ether) length() int { + return header.EthernetMinimumSize +} + +// merge implements Layer.merge. +func (l *Ether) merge(other Layer) error { + return mergeLayer(l, other) +} + +// IPv4 can construct and match an IPv4 encapsulation. +type IPv4 struct { + LayerBase + IHL *uint8 + TOS *uint8 + TotalLength *uint16 + ID *uint16 + Flags *uint8 + FragmentOffset *uint16 + TTL *uint8 + Protocol *uint8 + Checksum *uint16 + SrcAddr *tcpip.Address + DstAddr *tcpip.Address +} + +func (l *IPv4) String() string { + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *IPv4) ToBytes() ([]byte, error) { + b := make([]byte, header.IPv4MinimumSize) + h := header.IPv4(b) + fields := &header.IPv4Fields{ + IHL: 20, + TOS: 0, + TotalLength: 0, + ID: 0, + Flags: 0, + FragmentOffset: 0, + TTL: 64, + Protocol: 0, + Checksum: 0, + SrcAddr: tcpip.Address(""), + DstAddr: tcpip.Address(""), + } + if l.TOS != nil { + fields.TOS = *l.TOS + } + if l.TotalLength != nil { + fields.TotalLength = *l.TotalLength + } else { + fields.TotalLength = uint16(l.length()) + current := l.next() + for current != nil { + fields.TotalLength += uint16(current.length()) + current = current.next() + } + } + if l.ID != nil { + fields.ID = *l.ID + } + if l.Flags != nil { + fields.Flags = *l.Flags + } + if l.FragmentOffset != nil { + fields.FragmentOffset = *l.FragmentOffset + } + if l.TTL != nil { + fields.TTL = *l.TTL + } + if l.Protocol != nil { + fields.Protocol = *l.Protocol + } else { + switch n := l.next().(type) { + case *TCP: + fields.Protocol = uint8(header.TCPProtocolNumber) + case *UDP: + fields.Protocol = uint8(header.UDPProtocolNumber) + default: + // TODO(b/150301488): Support more protocols as needed. + return nil, fmt.Errorf("ipv4 header's next layer is unrecognized: %#v", n) + } + } + if l.SrcAddr != nil { + fields.SrcAddr = *l.SrcAddr + } + if l.DstAddr != nil { + fields.DstAddr = *l.DstAddr + } + if l.Checksum != nil { + fields.Checksum = *l.Checksum + } + h.Encode(fields) + if l.Checksum == nil { + h.SetChecksum(^h.CalculateChecksum()) + } + return h, nil +} + +// Uint16 is a helper routine that allocates a new +// uint16 value to store v and returns a pointer to it. +func Uint16(v uint16) *uint16 { + return &v +} + +// Uint8 is a helper routine that allocates a new +// uint8 value to store v and returns a pointer to it. +func Uint8(v uint8) *uint8 { + return &v +} + +// Address is a helper routine that allocates a new tcpip.Address value to store +// v and returns a pointer to it. +func Address(v tcpip.Address) *tcpip.Address { + return &v +} + +// parseIPv4 parses the bytes assuming that they start with an ipv4 header and +// continues parsing further encapsulations. +func parseIPv4(b []byte) (Layer, layerParser) { + h := header.IPv4(b) + tos, _ := h.TOS() + ipv4 := IPv4{ + IHL: Uint8(h.HeaderLength()), + TOS: &tos, + TotalLength: Uint16(h.TotalLength()), + ID: Uint16(h.ID()), + Flags: Uint8(h.Flags()), + FragmentOffset: Uint16(h.FragmentOffset()), + TTL: Uint8(h.TTL()), + Protocol: Uint8(h.Protocol()), + Checksum: Uint16(h.Checksum()), + SrcAddr: Address(h.SourceAddress()), + DstAddr: Address(h.DestinationAddress()), + } + var nextParser layerParser + switch h.TransportProtocol() { + case header.TCPProtocolNumber: + nextParser = parseTCP + case header.UDPProtocolNumber: + nextParser = parseUDP + default: + // Assume that the rest is a payload. + nextParser = parsePayload + } + return &ipv4, nextParser +} + +func (l *IPv4) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *IPv4) length() int { + if l.IHL == nil { + return header.IPv4MinimumSize + } + return int(*l.IHL) +} + +// merge implements Layer.merge. +func (l *IPv4) merge(other Layer) error { + return mergeLayer(l, other) +} + +// IPv6 can construct and match an IPv6 encapsulation. +type IPv6 struct { + LayerBase + TrafficClass *uint8 + FlowLabel *uint32 + PayloadLength *uint16 + NextHeader *uint8 + HopLimit *uint8 + SrcAddr *tcpip.Address + DstAddr *tcpip.Address +} + +func (l *IPv6) String() string { + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *IPv6) ToBytes() ([]byte, error) { + b := make([]byte, header.IPv6MinimumSize) + h := header.IPv6(b) + fields := &header.IPv6Fields{ + HopLimit: 64, + } + if l.TrafficClass != nil { + fields.TrafficClass = *l.TrafficClass + } + if l.FlowLabel != nil { + fields.FlowLabel = *l.FlowLabel + } + if l.PayloadLength != nil { + fields.PayloadLength = *l.PayloadLength + } else { + for current := l.next(); current != nil; current = current.next() { + fields.PayloadLength += uint16(current.length()) + } + } + if l.NextHeader != nil { + fields.NextHeader = *l.NextHeader + } else { + switch n := l.next().(type) { + case *TCP: + fields.NextHeader = uint8(header.TCPProtocolNumber) + case *UDP: + fields.NextHeader = uint8(header.UDPProtocolNumber) + case *ICMPv6: + fields.NextHeader = uint8(header.ICMPv6ProtocolNumber) + default: + // TODO(b/150301488): Support more protocols as needed. + return nil, fmt.Errorf("ToBytes can't deduce the IPv6 header's next protocol: %#v", n) + } + } + if l.HopLimit != nil { + fields.HopLimit = *l.HopLimit + } + if l.SrcAddr != nil { + fields.SrcAddr = *l.SrcAddr + } + if l.DstAddr != nil { + fields.DstAddr = *l.DstAddr + } + h.Encode(fields) + return h, nil +} + +// parseIPv6 parses the bytes assuming that they start with an ipv6 header and +// continues parsing further encapsulations. +func parseIPv6(b []byte) (Layer, layerParser) { + h := header.IPv6(b) + tos, flowLabel := h.TOS() + ipv6 := IPv6{ + TrafficClass: &tos, + FlowLabel: &flowLabel, + PayloadLength: Uint16(h.PayloadLength()), + NextHeader: Uint8(h.NextHeader()), + HopLimit: Uint8(h.HopLimit()), + SrcAddr: Address(h.SourceAddress()), + DstAddr: Address(h.DestinationAddress()), + } + var nextParser layerParser + switch h.TransportProtocol() { + case header.TCPProtocolNumber: + nextParser = parseTCP + case header.UDPProtocolNumber: + nextParser = parseUDP + case header.ICMPv6ProtocolNumber: + nextParser = parseICMPv6 + default: + // Assume that the rest is a payload. + nextParser = parsePayload + } + return &ipv6, nextParser +} + +func (l *IPv6) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *IPv6) length() int { + return header.IPv6MinimumSize +} + +// merge overrides the values in l with the values from other but only in fields +// where the value is not nil. +func (l *IPv6) merge(other Layer) error { + return mergeLayer(l, other) +} + +// ICMPv6 can construct and match an ICMPv6 encapsulation. +type ICMPv6 struct { + LayerBase + Type *header.ICMPv6Type + Code *byte + Checksum *uint16 + NDPPayload []byte +} + +func (l *ICMPv6) String() string { + // TODO(eyalsoha): Do something smarter here when *l.Type is ParameterProblem? + // We could parse the contents of the Payload as if it were an IPv6 packet. + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *ICMPv6) ToBytes() ([]byte, error) { + b := make([]byte, header.ICMPv6HeaderSize+len(l.NDPPayload)) + h := header.ICMPv6(b) + if l.Type != nil { + h.SetType(*l.Type) + } + if l.Code != nil { + h.SetCode(*l.Code) + } + copy(h.NDPPayload(), l.NDPPayload) + if l.Checksum != nil { + h.SetChecksum(*l.Checksum) + } else { + ipv6 := l.prev().(*IPv6) + h.SetChecksum(header.ICMPv6Checksum(h, *ipv6.SrcAddr, *ipv6.DstAddr, buffer.VectorisedView{})) + } + return h, nil +} + +// ICMPv6Type is a helper routine that allocates a new ICMPv6Type value to store +// v and returns a pointer to it. +func ICMPv6Type(v header.ICMPv6Type) *header.ICMPv6Type { + return &v +} + +// Byte is a helper routine that allocates a new byte value to store +// v and returns a pointer to it. +func Byte(v byte) *byte { + return &v +} + +// parseICMPv6 parses the bytes assuming that they start with an ICMPv6 header. +func parseICMPv6(b []byte) (Layer, layerParser) { + h := header.ICMPv6(b) + icmpv6 := ICMPv6{ + Type: ICMPv6Type(h.Type()), + Code: Byte(h.Code()), + Checksum: Uint16(h.Checksum()), + NDPPayload: h.NDPPayload(), + } + return &icmpv6, nil +} + +func (l *ICMPv6) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *ICMPv6) length() int { + return header.ICMPv6HeaderSize + len(l.NDPPayload) +} + +// merge overrides the values in l with the values from other but only in fields +// where the value is not nil. +func (l *ICMPv6) merge(other Layer) error { + return mergeLayer(l, other) +} + +// TCP can construct and match a TCP encapsulation. +type TCP struct { + LayerBase + SrcPort *uint16 + DstPort *uint16 + SeqNum *uint32 + AckNum *uint32 + DataOffset *uint8 + Flags *uint8 + WindowSize *uint16 + Checksum *uint16 + UrgentPointer *uint16 +} + +func (l *TCP) String() string { + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *TCP) ToBytes() ([]byte, error) { + b := make([]byte, header.TCPMinimumSize) + h := header.TCP(b) + if l.SrcPort != nil { + h.SetSourcePort(*l.SrcPort) + } + if l.DstPort != nil { + h.SetDestinationPort(*l.DstPort) + } + if l.SeqNum != nil { + h.SetSequenceNumber(*l.SeqNum) + } + if l.AckNum != nil { + h.SetAckNumber(*l.AckNum) + } + if l.DataOffset != nil { + h.SetDataOffset(*l.DataOffset) + } else { + h.SetDataOffset(uint8(l.length())) + } + if l.Flags != nil { + h.SetFlags(*l.Flags) + } + if l.WindowSize != nil { + h.SetWindowSize(*l.WindowSize) + } else { + h.SetWindowSize(32768) + } + if l.UrgentPointer != nil { + h.SetUrgentPoiner(*l.UrgentPointer) + } + if l.Checksum != nil { + h.SetChecksum(*l.Checksum) + return h, nil + } + if err := setTCPChecksum(&h, l); err != nil { + return nil, err + } + return h, nil +} + +// totalLength returns the length of the provided layer and all following +// layers. +func totalLength(l Layer) int { + var totalLength int + for ; l != nil; l = l.next() { + totalLength += l.length() + } + return totalLength +} + +// layerChecksum calculates the checksum of the Layer header, including the +// peusdeochecksum of the layer before it and all the bytes after it.. +func layerChecksum(l Layer, protoNumber tcpip.TransportProtocolNumber) (uint16, error) { + totalLength := uint16(totalLength(l)) + var xsum uint16 + switch s := l.prev().(type) { + case *IPv4: + xsum = header.PseudoHeaderChecksum(protoNumber, *s.SrcAddr, *s.DstAddr, totalLength) + default: + // TODO(b/150301488): Support more protocols, like IPv6. + return 0, fmt.Errorf("can't get src and dst addr from previous layer: %#v", s) + } + var payloadBytes buffer.VectorisedView + for current := l.next(); current != nil; current = current.next() { + payload, err := current.ToBytes() + if err != nil { + return 0, fmt.Errorf("can't get bytes for next header: %s", payload) + } + payloadBytes.AppendView(payload) + } + xsum = header.ChecksumVV(payloadBytes, xsum) + return xsum, nil +} + +// setTCPChecksum calculates the checksum of the TCP header and sets it in h. +func setTCPChecksum(h *header.TCP, tcp *TCP) error { + h.SetChecksum(0) + xsum, err := layerChecksum(tcp, header.TCPProtocolNumber) + if err != nil { + return err + } + h.SetChecksum(^h.CalculateChecksum(xsum)) + return nil +} + +// Uint32 is a helper routine that allocates a new +// uint32 value to store v and returns a pointer to it. +func Uint32(v uint32) *uint32 { + return &v +} + +// parseTCP parses the bytes assuming that they start with a tcp header and +// continues parsing further encapsulations. +func parseTCP(b []byte) (Layer, layerParser) { + h := header.TCP(b) + tcp := TCP{ + SrcPort: Uint16(h.SourcePort()), + DstPort: Uint16(h.DestinationPort()), + SeqNum: Uint32(h.SequenceNumber()), + AckNum: Uint32(h.AckNumber()), + DataOffset: Uint8(h.DataOffset()), + Flags: Uint8(h.Flags()), + WindowSize: Uint16(h.WindowSize()), + Checksum: Uint16(h.Checksum()), + UrgentPointer: Uint16(h.UrgentPointer()), + } + return &tcp, parsePayload +} + +func (l *TCP) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *TCP) length() int { + if l.DataOffset == nil { + return header.TCPMinimumSize + } + return int(*l.DataOffset) +} + +// merge implements Layer.merge. +func (l *TCP) merge(other Layer) error { + return mergeLayer(l, other) +} + +// UDP can construct and match a UDP encapsulation. +type UDP struct { + LayerBase + SrcPort *uint16 + DstPort *uint16 + Length *uint16 + Checksum *uint16 +} + +func (l *UDP) String() string { + return stringLayer(l) +} + +// ToBytes implements Layer.ToBytes. +func (l *UDP) ToBytes() ([]byte, error) { + b := make([]byte, header.UDPMinimumSize) + h := header.UDP(b) + if l.SrcPort != nil { + h.SetSourcePort(*l.SrcPort) + } + if l.DstPort != nil { + h.SetDestinationPort(*l.DstPort) + } + if l.Length != nil { + h.SetLength(*l.Length) + } else { + h.SetLength(uint16(totalLength(l))) + } + if l.Checksum != nil { + h.SetChecksum(*l.Checksum) + return h, nil + } + if err := setUDPChecksum(&h, l); err != nil { + return nil, err + } + return h, nil +} + +// setUDPChecksum calculates the checksum of the UDP header and sets it in h. +func setUDPChecksum(h *header.UDP, udp *UDP) error { + h.SetChecksum(0) + xsum, err := layerChecksum(udp, header.UDPProtocolNumber) + if err != nil { + return err + } + h.SetChecksum(^h.CalculateChecksum(xsum)) + return nil +} + +// parseUDP parses the bytes assuming that they start with a udp header and +// returns the parsed layer and the next parser to use. +func parseUDP(b []byte) (Layer, layerParser) { + h := header.UDP(b) + udp := UDP{ + SrcPort: Uint16(h.SourcePort()), + DstPort: Uint16(h.DestinationPort()), + Length: Uint16(h.Length()), + Checksum: Uint16(h.Checksum()), + } + return &udp, parsePayload +} + +func (l *UDP) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *UDP) length() int { + if l.Length == nil { + return header.UDPMinimumSize + } + return int(*l.Length) +} + +// merge implements Layer.merge. +func (l *UDP) merge(other Layer) error { + return mergeLayer(l, other) +} + +// Payload has bytes beyond OSI layer 4. +type Payload struct { + LayerBase + Bytes []byte +} + +func (l *Payload) String() string { + return stringLayer(l) +} + +// parsePayload parses the bytes assuming that they start with a payload and +// continue to the end. There can be no further encapsulations. +func parsePayload(b []byte) (Layer, layerParser) { + payload := Payload{ + Bytes: b, + } + return &payload, nil +} + +// ToBytes implements Layer.ToBytes. +func (l *Payload) ToBytes() ([]byte, error) { + return l.Bytes, nil +} + +func (l *Payload) match(other Layer) bool { + return equalLayer(l, other) +} + +func (l *Payload) length() int { + return len(l.Bytes) +} + +// merge implements Layer.merge. +func (l *Payload) merge(other Layer) error { + return mergeLayer(l, other) +} + +// Layers is an array of Layer and supports similar functions to Layer. +type Layers []Layer + +// linkLayers sets the linked-list ponters in ls. +func (ls *Layers) linkLayers() { + for i, l := range *ls { + if i > 0 { + l.setPrev((*ls)[i-1]) + } else { + l.setPrev(nil) + } + if i+1 < len(*ls) { + l.setNext((*ls)[i+1]) + } else { + l.setNext(nil) + } + } +} + +// ToBytes converts the Layers into bytes. It creates a linked list of the Layer +// structs and then concatentates the output of ToBytes on each Layer. +func (ls *Layers) ToBytes() ([]byte, error) { + ls.linkLayers() + outBytes := []byte{} + for _, l := range *ls { + layerBytes, err := l.ToBytes() + if err != nil { + return nil, err + } + outBytes = append(outBytes, layerBytes...) + } + return outBytes, nil +} + +func (ls *Layers) match(other Layers) bool { + if len(*ls) > len(other) { + return false + } + for i, l := range *ls { + if !equalLayer(l, other[i]) { + return false + } + } + return true +} + +// layerDiff stores the diffs for each field along with the label for the Layer. +// If rows is nil, that means that there was no diff. +type layerDiff struct { + label string + rows []layerDiffRow +} + +// layerDiffRow stores the fields and corresponding values for two got and want +// layers. If the value was nil then the string stored is the empty string. +type layerDiffRow struct { + field, got, want string +} + +// diffLayer extracts all differing fields between two layers. +func diffLayer(got, want Layer) []layerDiffRow { + vGot := reflect.ValueOf(got).Elem() + vWant := reflect.ValueOf(want).Elem() + if vGot.Type() != vWant.Type() { + return nil + } + t := vGot.Type() + var result []layerDiffRow + for i := 0; i < t.NumField(); i++ { + t := t.Field(i) + if t.Anonymous { + // Ignore the LayerBase in the Layer struct. + continue + } + vGot := vGot.Field(i) + vWant := vWant.Field(i) + gotString := "" + if !vGot.IsNil() { + gotString = fmt.Sprint(reflect.Indirect(vGot)) + } + wantString := "" + if !vWant.IsNil() { + wantString = fmt.Sprint(reflect.Indirect(vWant)) + } + result = append(result, layerDiffRow{t.Name, gotString, wantString}) + } + return result +} + +// layerType returns a concise string describing the type of the Layer, like +// "TCP", or "IPv6". +func layerType(l Layer) string { + return reflect.TypeOf(l).Elem().Name() +} + +// diff compares Layers and returns a representation of the difference. Each +// Layer in the Layers is pairwise compared. If an element in either is nil, it +// is considered a match with the other Layer. If two Layers have differing +// types, they don't match regardless of the contents. If two Layers have the +// same type then the fields in the Layer are pairwise compared. Fields that are +// nil always match. Two non-nil fields only match if they point to equal +// values. diff returns an empty string if and only if *ls and other match. +func (ls *Layers) diff(other Layers) string { + var allDiffs []layerDiff + // Check the cases where one list is longer than the other, where one or both + // elements are nil, where the sides have different types, and where the sides + // have the same type. + for i := 0; i < len(*ls) || i < len(other); i++ { + if i >= len(*ls) { + // Matching ls against other where other is longer than ls. missing + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "missing matches " + layerType(other[i]), + }) + continue + } + + if i >= len(other) { + // Matching ls against other where ls is longer than other. missing + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches missing", + }) + continue + } + + if (*ls)[i] == nil && other[i] == nil { + // Matching ls against other where both elements are nil. nil matches + // everything so we just include a label without any rows. Having no rows + // is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "nil matches nil", + }) + continue + } + + if (*ls)[i] == nil { + // Matching ls against other where the element in ls is nil. nil matches + // everything so we just include a label without any rows. Having no rows + // is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: "nil matches " + layerType(other[i]), + }) + continue + } + + if other[i] == nil { + // Matching ls against other where the element in other is nil. nil + // matches everything so we just include a label without any rows. Having + // no rows is a sign that there was no diff. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches nil", + }) + continue + } + + if reflect.TypeOf((*ls)[i]) == reflect.TypeOf(other[i]) { + // Matching ls against other where both elements have the same type. Match + // each field pairwise and only report a diff if there is a mismatch, + // which is only when both sides are non-nil and have differring values. + diff := diffLayer((*ls)[i], other[i]) + var layerDiffRows []layerDiffRow + for _, d := range diff { + if d.got == "" || d.want == "" || d.got == d.want { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + d.got, + d.want, + }) + } + if len(layerDiffRows) > 0 { + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]), + rows: layerDiffRows, + }) + } else { + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " matches " + layerType(other[i]), + // Having no rows is a sign that there was no diff. + }) + } + continue + } + // Neither side is nil and the types are different, so we'll display one + // side then the other. + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]) + " doesn't match " + layerType(other[i]), + }) + diff := diffLayer((*ls)[i], (*ls)[i]) + layerDiffRows := []layerDiffRow{} + for _, d := range diff { + if len(d.got) == 0 { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + d.got, + "", + }) + } + allDiffs = append(allDiffs, layerDiff{ + label: layerType((*ls)[i]), + rows: layerDiffRows, + }) + + layerDiffRows = []layerDiffRow{} + diff = diffLayer(other[i], other[i]) + for _, d := range diff { + if len(d.want) == 0 { + continue + } + layerDiffRows = append(layerDiffRows, layerDiffRow{ + d.field, + "", + d.want, + }) + } + allDiffs = append(allDiffs, layerDiff{ + label: layerType(other[i]), + rows: layerDiffRows, + }) + } + + output := "" + // These are for output formatting. + maxLabelLen, maxFieldLen, maxGotLen, maxWantLen := 0, 0, 0, 0 + foundOne := false + for _, l := range allDiffs { + if len(l.label) > maxLabelLen && len(l.rows) > 0 { + maxLabelLen = len(l.label) + } + if l.rows != nil { + foundOne = true + } + for _, r := range l.rows { + if len(r.field) > maxFieldLen { + maxFieldLen = len(r.field) + } + if l := len(fmt.Sprint(r.got)); l > maxGotLen { + maxGotLen = l + } + if l := len(fmt.Sprint(r.want)); l > maxWantLen { + maxWantLen = l + } + } + } + if !foundOne { + return "" + } + for _, l := range allDiffs { + if len(l.rows) == 0 { + output += "(" + l.label + ")\n" + continue + } + for i, r := range l.rows { + var label string + if i == 0 { + label = l.label + ":" + } + output += fmt.Sprintf( + "%*s %*s %*v %*v\n", + maxLabelLen+1, label, + maxFieldLen+1, r.field+":", + maxGotLen, r.got, + maxWantLen, r.want, + ) + } + } + return output +} + +// merge merges the other Layers into ls. If the other Layers is longer, those +// additional Layer structs are added to ls. The errors from merging are +// collected and returned. +func (ls *Layers) merge(other Layers) error { + var errs error + for i, o := range other { + if i < len(*ls) { + errs = multierr.Combine(errs, (*ls)[i].merge(o)) + } else { + *ls = append(*ls, o) + } + } + return errs +} diff --git a/test/packetimpact/testbench/layers_test.go b/test/packetimpact/testbench/layers_test.go new file mode 100644 index 000000000..96f72de5b --- /dev/null +++ b/test/packetimpact/testbench/layers_test.go @@ -0,0 +1,395 @@ +// 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 ( + "testing" + + "github.com/mohae/deepcopy" + "gvisor.dev/gvisor/pkg/tcpip" +) + +func TestLayerMatch(t *testing.T) { + var nilPayload *Payload + noPayload := &Payload{} + emptyPayload := &Payload{Bytes: []byte{}} + fullPayload := &Payload{Bytes: []byte{1, 2, 3}} + emptyTCP := &TCP{SrcPort: Uint16(1234), LayerBase: LayerBase{nextLayer: emptyPayload}} + fullTCP := &TCP{SrcPort: Uint16(1234), LayerBase: LayerBase{nextLayer: fullPayload}} + for _, tt := range []struct { + a, b Layer + want bool + }{ + {nilPayload, nilPayload, true}, + {nilPayload, noPayload, true}, + {nilPayload, emptyPayload, true}, + {nilPayload, fullPayload, true}, + {noPayload, noPayload, true}, + {noPayload, emptyPayload, true}, + {noPayload, fullPayload, true}, + {emptyPayload, emptyPayload, true}, + {emptyPayload, fullPayload, false}, + {fullPayload, fullPayload, true}, + {emptyTCP, fullTCP, true}, + } { + if got := tt.a.match(tt.b); got != tt.want { + t.Errorf("%s.match(%s) = %t, want %t", tt.a, tt.b, got, tt.want) + } + if got := tt.b.match(tt.a); got != tt.want { + t.Errorf("%s.match(%s) = %t, want %t", tt.b, tt.a, got, tt.want) + } + } +} + +func TestLayerMergeMismatch(t *testing.T) { + tcp := &TCP{} + otherTCP := &TCP{} + ipv4 := &IPv4{} + ether := &Ether{} + for _, tt := range []struct { + a, b Layer + success bool + }{ + {tcp, tcp, true}, + {tcp, otherTCP, true}, + {tcp, ipv4, false}, + {tcp, ether, false}, + {tcp, nil, true}, + + {otherTCP, otherTCP, true}, + {otherTCP, ipv4, false}, + {otherTCP, ether, false}, + {otherTCP, nil, true}, + + {ipv4, ipv4, true}, + {ipv4, ether, false}, + {ipv4, nil, true}, + + {ether, ether, true}, + {ether, nil, true}, + } { + if err := tt.a.merge(tt.b); (err == nil) != tt.success { + t.Errorf("%s.merge(%s) got %s, wanted the opposite", tt.a, tt.b, err) + } + if tt.b != nil { + if err := tt.b.merge(tt.a); (err == nil) != tt.success { + t.Errorf("%s.merge(%s) got %s, wanted the opposite", tt.b, tt.a, err) + } + } + } +} + +func TestLayerMerge(t *testing.T) { + zero := Uint32(0) + one := Uint32(1) + two := Uint32(2) + empty := []byte{} + foo := []byte("foo") + bar := []byte("bar") + for _, tt := range []struct { + a, b Layer + want Layer + }{ + {&TCP{AckNum: nil}, &TCP{AckNum: nil}, &TCP{AckNum: nil}}, + {&TCP{AckNum: nil}, &TCP{AckNum: zero}, &TCP{AckNum: zero}}, + {&TCP{AckNum: nil}, &TCP{AckNum: one}, &TCP{AckNum: one}}, + {&TCP{AckNum: nil}, &TCP{AckNum: two}, &TCP{AckNum: two}}, + {&TCP{AckNum: nil}, nil, &TCP{AckNum: nil}}, + + {&TCP{AckNum: zero}, &TCP{AckNum: nil}, &TCP{AckNum: zero}}, + {&TCP{AckNum: zero}, &TCP{AckNum: zero}, &TCP{AckNum: zero}}, + {&TCP{AckNum: zero}, &TCP{AckNum: one}, &TCP{AckNum: one}}, + {&TCP{AckNum: zero}, &TCP{AckNum: two}, &TCP{AckNum: two}}, + {&TCP{AckNum: zero}, nil, &TCP{AckNum: zero}}, + + {&TCP{AckNum: one}, &TCP{AckNum: nil}, &TCP{AckNum: one}}, + {&TCP{AckNum: one}, &TCP{AckNum: zero}, &TCP{AckNum: zero}}, + {&TCP{AckNum: one}, &TCP{AckNum: one}, &TCP{AckNum: one}}, + {&TCP{AckNum: one}, &TCP{AckNum: two}, &TCP{AckNum: two}}, + {&TCP{AckNum: one}, nil, &TCP{AckNum: one}}, + + {&TCP{AckNum: two}, &TCP{AckNum: nil}, &TCP{AckNum: two}}, + {&TCP{AckNum: two}, &TCP{AckNum: zero}, &TCP{AckNum: zero}}, + {&TCP{AckNum: two}, &TCP{AckNum: one}, &TCP{AckNum: one}}, + {&TCP{AckNum: two}, &TCP{AckNum: two}, &TCP{AckNum: two}}, + {&TCP{AckNum: two}, nil, &TCP{AckNum: two}}, + + {&Payload{Bytes: nil}, &Payload{Bytes: nil}, &Payload{Bytes: nil}}, + {&Payload{Bytes: nil}, &Payload{Bytes: empty}, &Payload{Bytes: empty}}, + {&Payload{Bytes: nil}, &Payload{Bytes: foo}, &Payload{Bytes: foo}}, + {&Payload{Bytes: nil}, &Payload{Bytes: bar}, &Payload{Bytes: bar}}, + {&Payload{Bytes: nil}, nil, &Payload{Bytes: nil}}, + + {&Payload{Bytes: empty}, &Payload{Bytes: nil}, &Payload{Bytes: empty}}, + {&Payload{Bytes: empty}, &Payload{Bytes: empty}, &Payload{Bytes: empty}}, + {&Payload{Bytes: empty}, &Payload{Bytes: foo}, &Payload{Bytes: foo}}, + {&Payload{Bytes: empty}, &Payload{Bytes: bar}, &Payload{Bytes: bar}}, + {&Payload{Bytes: empty}, nil, &Payload{Bytes: empty}}, + + {&Payload{Bytes: foo}, &Payload{Bytes: nil}, &Payload{Bytes: foo}}, + {&Payload{Bytes: foo}, &Payload{Bytes: empty}, &Payload{Bytes: empty}}, + {&Payload{Bytes: foo}, &Payload{Bytes: foo}, &Payload{Bytes: foo}}, + {&Payload{Bytes: foo}, &Payload{Bytes: bar}, &Payload{Bytes: bar}}, + {&Payload{Bytes: foo}, nil, &Payload{Bytes: foo}}, + + {&Payload{Bytes: bar}, &Payload{Bytes: nil}, &Payload{Bytes: bar}}, + {&Payload{Bytes: bar}, &Payload{Bytes: empty}, &Payload{Bytes: empty}}, + {&Payload{Bytes: bar}, &Payload{Bytes: foo}, &Payload{Bytes: foo}}, + {&Payload{Bytes: bar}, &Payload{Bytes: bar}, &Payload{Bytes: bar}}, + {&Payload{Bytes: bar}, nil, &Payload{Bytes: bar}}, + } { + a := deepcopy.Copy(tt.a).(Layer) + if err := a.merge(tt.b); err != nil { + t.Errorf("%s.merge(%s) = %s, wanted nil", tt.a, tt.b, err) + continue + } + if a.String() != tt.want.String() { + t.Errorf("%s.merge(%s) merge result got %s, want %s", tt.a, tt.b, a, tt.want) + } + } +} + +func TestLayerStringFormat(t *testing.T) { + for _, tt := range []struct { + name string + l Layer + want string + }{ + { + name: "TCP", + l: &TCP{ + SrcPort: Uint16(34785), + DstPort: Uint16(47767), + SeqNum: Uint32(3452155723), + AckNum: Uint32(2596996163), + DataOffset: Uint8(5), + Flags: Uint8(20), + WindowSize: Uint16(64240), + Checksum: Uint16(0x2e2b), + }, + want: "&testbench.TCP{" + + "SrcPort:34785 " + + "DstPort:47767 " + + "SeqNum:3452155723 " + + "AckNum:2596996163 " + + "DataOffset:5 " + + "Flags:20 " + + "WindowSize:64240 " + + "Checksum:11819" + + "}", + }, + { + name: "UDP", + l: &UDP{ + SrcPort: Uint16(34785), + DstPort: Uint16(47767), + Length: Uint16(12), + }, + want: "&testbench.UDP{" + + "SrcPort:34785 " + + "DstPort:47767 " + + "Length:12" + + "}", + }, + { + name: "IPv4", + l: &IPv4{ + IHL: Uint8(5), + TOS: Uint8(0), + TotalLength: Uint16(44), + ID: Uint16(0), + Flags: Uint8(2), + FragmentOffset: Uint16(0), + TTL: Uint8(64), + Protocol: Uint8(6), + Checksum: Uint16(0x2e2b), + SrcAddr: Address(tcpip.Address([]byte{197, 34, 63, 10})), + DstAddr: Address(tcpip.Address([]byte{197, 34, 63, 20})), + }, + want: "&testbench.IPv4{" + + "IHL:5 " + + "TOS:0 " + + "TotalLength:44 " + + "ID:0 " + + "Flags:2 " + + "FragmentOffset:0 " + + "TTL:64 " + + "Protocol:6 " + + "Checksum:11819 " + + "SrcAddr:197.34.63.10 " + + "DstAddr:197.34.63.20" + + "}", + }, + { + name: "Ether", + l: &Ether{ + SrcAddr: LinkAddress(tcpip.LinkAddress([]byte{0x02, 0x42, 0xc5, 0x22, 0x3f, 0x0a})), + DstAddr: LinkAddress(tcpip.LinkAddress([]byte{0x02, 0x42, 0xc5, 0x22, 0x3f, 0x14})), + Type: NetworkProtocolNumber(4), + }, + want: "&testbench.Ether{" + + "SrcAddr:02:42:c5:22:3f:0a " + + "DstAddr:02:42:c5:22:3f:14 " + + "Type:4" + + "}", + }, + { + name: "Payload", + l: &Payload{ + Bytes: []byte("Hooray for packetimpact."), + }, + want: "&testbench.Payload{Bytes:\n" + + "00000000 48 6f 6f 72 61 79 20 66 6f 72 20 70 61 63 6b 65 |Hooray for packe|\n" + + "00000010 74 69 6d 70 61 63 74 2e |timpact.|\n" + + "}", + }, + } { + t.Run(tt.name, func(t *testing.T) { + if got := tt.l.String(); got != tt.want { + t.Errorf("%s.String() = %s, want: %s", tt.name, got, tt.want) + } + }) + } +} + +func TestConnectionMatch(t *testing.T) { + conn := Connection{ + layerStates: []layerState{ðerState{}}, + } + protoNum0 := tcpip.NetworkProtocolNumber(0) + protoNum1 := tcpip.NetworkProtocolNumber(1) + for _, tt := range []struct { + description string + override, received Layers + wantMatch bool + }{ + { + description: "shorter override", + override: []Layer{&Ether{}}, + received: []Layer{&Ether{}, &Payload{Bytes: []byte("hello")}}, + wantMatch: true, + }, + { + description: "longer override", + override: []Layer{&Ether{}, &Payload{Bytes: []byte("hello")}}, + received: []Layer{&Ether{}}, + wantMatch: false, + }, + { + description: "ether layer mismatch", + override: []Layer{&Ether{Type: &protoNum0}}, + received: []Layer{&Ether{Type: &protoNum1}}, + wantMatch: false, + }, + { + description: "both nil", + override: nil, + received: nil, + wantMatch: false, + }, + { + description: "nil override", + override: nil, + received: []Layer{&Ether{}}, + wantMatch: true, + }, + } { + t.Run(tt.description, func(t *testing.T) { + if gotMatch := conn.match(tt.override, tt.received); gotMatch != tt.wantMatch { + t.Fatalf("conn.match(%s, %s) = %t, want %t", tt.override, tt.received, gotMatch, tt.wantMatch) + } + }) + } +} + +func TestLayersDiff(t *testing.T) { + for _, tt := range []struct { + x, y Layers + want string + }{ + { + Layers{&Ether{Type: NetworkProtocolNumber(12)}, &TCP{DataOffset: Uint8(5), SeqNum: Uint32(5)}}, + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + "Ether: Type: 12 13\n" + + " TCP: SeqNum: 5 6\n" + + " DataOffset: 5 7\n", + }, + { + Layers{&Ether{Type: NetworkProtocolNumber(12)}, &UDP{SrcPort: Uint16(123)}}, + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + "Ether: Type: 12 13\n" + + "(UDP doesn't match TCP)\n" + + " UDP: SrcPort: 123 \n" + + " TCP: SeqNum: 6\n" + + " DataOffset: 7\n", + }, + { + Layers{&UDP{SrcPort: Uint16(123)}}, + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + "(UDP doesn't match Ether)\n" + + " UDP: SrcPort: 123 \n" + + "Ether: Type: 13\n" + + "(missing matches TCP)\n", + }, + { + Layers{nil, &UDP{SrcPort: Uint16(123)}}, + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + "(nil matches Ether)\n" + + "(UDP doesn't match TCP)\n" + + "UDP: SrcPort: 123 \n" + + "TCP: SeqNum: 6\n" + + " DataOffset: 7\n", + }, + { + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &IPv4{IHL: Uint8(4)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + Layers{&Ether{Type: NetworkProtocolNumber(13)}, &IPv4{IHL: Uint8(6)}, &TCP{DataOffset: Uint8(7), SeqNum: Uint32(6)}}, + "(Ether matches Ether)\n" + + "IPv4: IHL: 4 6\n" + + "(TCP matches TCP)\n", + }, + { + Layers{&Payload{Bytes: []byte("foo")}}, + Layers{&Payload{Bytes: []byte("bar")}}, + "Payload: Bytes: [102 111 111] [98 97 114]\n", + }, + { + Layers{&Payload{Bytes: []byte("")}}, + Layers{&Payload{}}, + "", + }, + { + Layers{&Payload{Bytes: []byte("")}}, + Layers{&Payload{Bytes: []byte("")}}, + "", + }, + { + Layers{&UDP{}}, + Layers{&TCP{}}, + "(UDP doesn't match TCP)\n" + + "(UDP)\n" + + "(TCP)\n", + }, + } { + if got := tt.x.diff(tt.y); got != tt.want { + t.Errorf("%s.diff(%s) = %q, want %q", tt.x, tt.y, got, tt.want) + } + if tt.x.match(tt.y) != (tt.x.diff(tt.y) == "") { + t.Errorf("match and diff of %s and %s disagree", tt.x, tt.y) + } + if tt.y.match(tt.x) != (tt.y.diff(tt.x) == "") { + t.Errorf("match and diff of %s and %s disagree", tt.y, tt.x) + } + } +} diff --git a/test/packetimpact/testbench/rawsockets.go b/test/packetimpact/testbench/rawsockets.go new file mode 100644 index 000000000..ff722d4a6 --- /dev/null +++ b/test/packetimpact/testbench/rawsockets.go @@ -0,0 +1,183 @@ +// 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" + "fmt" + "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 + } + if err := unix.SetsockoptInt(snifferFd, unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, 1); err != nil { + t.Fatalf("can't set sockopt SO_RCVBUFFORCE to 1: %s", err) + } + if err := unix.SetsockoptInt(snifferFd, unix.SOL_SOCKET, unix.SO_RCVBUF, 1e7); err != nil { + t.Fatalf("can't setsockopt SO_RCVBUF to 10M: %s", 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] + } +} + +// Drain drains the Sniffer's socket receive buffer by receiving until there's +// nothing else to receive. +func (s *Sniffer) Drain() { + s.t.Helper() + flags, err := unix.FcntlInt(uintptr(s.fd), unix.F_GETFL, 0) + if err != nil { + s.t.Fatalf("failed to get sniffer socket fd flags: %s", err) + } + if _, err := unix.FcntlInt(uintptr(s.fd), unix.F_SETFL, flags|unix.O_NONBLOCK); err != nil { + s.t.Fatalf("failed to make sniffer socket non-blocking: %s", err) + } + for { + buf := make([]byte, maxReadSize) + _, _, err := unix.Recvfrom(s.fd, buf, unix.MSG_TRUNC) + if err == unix.EINTR || err == unix.EAGAIN || err == unix.EWOULDBLOCK { + break + } + } + if _, err := unix.FcntlInt(uintptr(s.fd), unix.F_SETFL, flags); err != nil { + s.t.Fatalf("failed to restore sniffer socket fd flags: %s", err) + } +} + +// close the socket that Sniffer is using. +func (s *Sniffer) close() error { + if err := unix.Close(s.fd); err != nil { + return fmt.Errorf("can't close sniffer socket: %w", err) + } + s.fd = -1 + return nil +} + +// 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() error { + if err := unix.Close(i.fd); err != nil { + return fmt.Errorf("can't close sniffer socket: %w", err) + } + i.fd = -1 + return nil +} |