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[NETPATH-371] Move common functions to separate package, create separ…
…ate testutils package (#31819)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,160 @@ | ||
| // Unless explicitly stated otherwise all files in this repository are licensed | ||
| // under the Apache License Version 2.0. | ||
| // This product includes software developed at Datadog (https://www.datadoghq.com/). | ||
| // Copyright 2016-present Datadog, Inc. | ||
|
|
||
| // Package common contains common functionality for both TCP and UDP | ||
| // traceroute implementations | ||
| package common | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "net" | ||
| "strconv" | ||
| "time" | ||
|
|
||
| "github.com/DataDog/datadog-agent/pkg/util/log" | ||
| "github.com/google/gopacket" | ||
| "github.com/google/gopacket/layers" | ||
| "golang.org/x/net/ipv4" | ||
| ) | ||
|
|
||
| const ( | ||
| // IPProtoICMP is the IP protocol number for ICMP | ||
| // we create our own constant here because there are | ||
| // different imports for the constant in different | ||
| // operating systems | ||
| IPProtoICMP = 1 | ||
| ) | ||
|
|
||
| type ( | ||
| // Results encapsulates a response from the | ||
| // traceroute | ||
| Results struct { | ||
| Source net.IP | ||
| SourcePort uint16 | ||
| Target net.IP | ||
| DstPort uint16 | ||
| Hops []*Hop | ||
| } | ||
|
|
||
| // Hop encapsulates information about a single | ||
| // hop in a traceroute | ||
| Hop struct { | ||
| IP net.IP | ||
| Port uint16 | ||
| ICMPType layers.ICMPv4TypeCode | ||
| RTT time.Duration | ||
| IsDest bool | ||
| } | ||
|
|
||
| // CanceledError is sent when a listener | ||
| // is canceled | ||
| CanceledError string | ||
|
|
||
| // ICMPResponse encapsulates the data from | ||
| // an ICMP response packet needed for matching | ||
| ICMPResponse struct { | ||
| SrcIP net.IP | ||
| DstIP net.IP | ||
| TypeCode layers.ICMPv4TypeCode | ||
| InnerSrcIP net.IP | ||
| InnerDstIP net.IP | ||
| InnerSrcPort uint16 | ||
| InnerDstPort uint16 | ||
| InnerSeqNum uint32 | ||
| } | ||
| ) | ||
|
|
||
| func (c CanceledError) Error() string { | ||
| return string(c) | ||
| } | ||
|
|
||
| // LocalAddrForHost takes in a destionation IP and port and returns the local | ||
| // address that should be used to connect to the destination | ||
| func LocalAddrForHost(destIP net.IP, destPort uint16) (*net.UDPAddr, error) { | ||
| // this is a quick way to get the local address for connecting to the host | ||
| // using UDP as the network type to avoid actually creating a connection to | ||
| // the host, just get the OS to give us a local IP and local ephemeral port | ||
| conn, err := net.Dial("udp4", net.JoinHostPort(destIP.String(), strconv.Itoa(int(destPort)))) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| defer conn.Close() | ||
| localAddr := conn.LocalAddr() | ||
|
|
||
| localUDPAddr, ok := localAddr.(*net.UDPAddr) | ||
| if !ok { | ||
| return nil, fmt.Errorf("invalid address type for %s: want %T, got %T", localAddr, localUDPAddr, localAddr) | ||
| } | ||
|
|
||
| return localUDPAddr, nil | ||
| } | ||
|
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||
| // ParseICMP takes in an IPv4 header and payload and tries to convert to an ICMP | ||
| // message, it returns all the fields from the packet we need to validate it's the response | ||
| // we're looking for | ||
| func ParseICMP(header *ipv4.Header, payload []byte) (*ICMPResponse, error) { | ||
| // in addition to parsing, it is probably not a bad idea to do some validation | ||
| // so we can ignore the ICMP packets we don't care about | ||
| icmpResponse := ICMPResponse{} | ||
|
|
||
| if header.Protocol != IPProtoICMP || header.Version != 4 || | ||
| header.Src == nil || header.Dst == nil { | ||
| return nil, fmt.Errorf("invalid IP header for ICMP packet: %+v", header) | ||
| } | ||
| icmpResponse.SrcIP = header.Src | ||
| icmpResponse.DstIP = header.Dst | ||
|
|
||
| var icmpv4Layer layers.ICMPv4 | ||
| decoded := []gopacket.LayerType{} | ||
| icmpParser := gopacket.NewDecodingLayerParser(layers.LayerTypeICMPv4, &icmpv4Layer) | ||
| icmpParser.IgnoreUnsupported = true // ignore unsupported layers, we will decode them in the next step | ||
| if err := icmpParser.DecodeLayers(payload, &decoded); err != nil { | ||
| return nil, fmt.Errorf("failed to decode ICMP packet: %w", err) | ||
| } | ||
| // since we ignore unsupported layers, we need to check if we actually decoded | ||
| // anything | ||
| if len(decoded) < 1 { | ||
| return nil, fmt.Errorf("failed to decode ICMP packet, no layers decoded") | ||
| } | ||
| icmpResponse.TypeCode = icmpv4Layer.TypeCode | ||
|
|
||
| var icmpPayload []byte | ||
| if len(icmpv4Layer.Payload) < 40 { | ||
| log.Tracef("Payload length %d is less than 40, extending...\n", len(icmpv4Layer.Payload)) | ||
| icmpPayload = make([]byte, 40) | ||
| copy(icmpPayload, icmpv4Layer.Payload) | ||
| // we have to set this in order for the TCP | ||
| // parser to work | ||
| icmpPayload[32] = 5 << 4 // set data offset | ||
| } else { | ||
| icmpPayload = icmpv4Layer.Payload | ||
| } | ||
|
|
||
| // a separate parser is needed to decode the inner IP and TCP headers because | ||
| // gopacket doesn't support this type of nesting in a single decoder | ||
| var innerIPLayer layers.IPv4 | ||
| var innerTCPLayer layers.TCP | ||
| innerIPParser := gopacket.NewDecodingLayerParser(layers.LayerTypeIPv4, &innerIPLayer, &innerTCPLayer) | ||
| if err := innerIPParser.DecodeLayers(icmpPayload, &decoded); err != nil { | ||
| return nil, fmt.Errorf("failed to decode inner ICMP payload: %w", err) | ||
| } | ||
| icmpResponse.InnerSrcIP = innerIPLayer.SrcIP | ||
| icmpResponse.InnerDstIP = innerIPLayer.DstIP | ||
| icmpResponse.InnerSrcPort = uint16(innerTCPLayer.SrcPort) | ||
| icmpResponse.InnerDstPort = uint16(innerTCPLayer.DstPort) | ||
| icmpResponse.InnerSeqNum = innerTCPLayer.Seq | ||
|
|
||
| return &icmpResponse, nil | ||
| } | ||
|
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||
| // ICMPMatch checks if an ICMP response matches the expected response | ||
| // based on the local and remote IP, port, and sequence number | ||
| func ICMPMatch(localIP net.IP, localPort uint16, remoteIP net.IP, remotePort uint16, seqNum uint32, response *ICMPResponse) bool { | ||
| return localIP.Equal(response.InnerSrcIP) && | ||
| remoteIP.Equal(response.InnerDstIP) && | ||
| localPort == response.InnerSrcPort && | ||
| remotePort == response.InnerDstPort && | ||
| seqNum == response.InnerSeqNum | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,117 @@ | ||
| // Unless explicitly stated otherwise all files in this repository are licensed | ||
| // under the Apache License Version 2.0. | ||
| // This product includes software developed at Datadog (https://www.datadoghq.com/). | ||
| // Copyright 2016-present Datadog, Inc. | ||
|
|
||
| //go:build test | ||
|
|
||
| package common | ||
|
|
||
| import ( | ||
| "net" | ||
| "testing" | ||
|
|
||
| "github.com/DataDog/datadog-agent/pkg/networkpath/traceroute/testutils" | ||
| "github.com/google/gopacket/layers" | ||
| "github.com/stretchr/testify/assert" | ||
| "github.com/stretchr/testify/require" | ||
| "golang.org/x/net/ipv4" | ||
| ) | ||
|
|
||
| var ( | ||
| srcIP = net.ParseIP("1.2.3.4") | ||
| dstIP = net.ParseIP("5.6.7.8") | ||
|
|
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| innerSrcIP = net.ParseIP("10.0.0.1") | ||
| innerDstIP = net.ParseIP("192.168.1.1") | ||
| ) | ||
|
|
||
| func Test_parseICMP(t *testing.T) { | ||
| ipv4Header := testutils.CreateMockIPv4Header(srcIP, dstIP, 1) | ||
| icmpLayer := testutils.CreateMockICMPLayer(layers.ICMPv4CodeTTLExceeded) | ||
| innerIPv4Layer := testutils.CreateMockIPv4Layer(innerSrcIP, innerDstIP, layers.IPProtocolTCP) | ||
| innerTCPLayer := testutils.CreateMockTCPLayer(12345, 443, 28394, 12737, true, true, true) | ||
|
|
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| tt := []struct { | ||
| description string | ||
| inHeader *ipv4.Header | ||
| inPayload []byte | ||
| expected *ICMPResponse | ||
| errMsg string | ||
| }{ | ||
| { | ||
| description: "empty IPv4 layer should return an error", | ||
| inHeader: &ipv4.Header{}, | ||
| inPayload: []byte{}, | ||
| expected: nil, | ||
| errMsg: "invalid IP header for ICMP packet", | ||
| }, | ||
| { | ||
| description: "missing ICMP layer should return an error", | ||
| inHeader: ipv4Header, | ||
| inPayload: []byte{}, | ||
| expected: nil, | ||
| errMsg: "failed to decode ICMP packet", | ||
| }, | ||
| { | ||
| description: "missing inner layers should return an error", | ||
| inHeader: ipv4Header, | ||
| inPayload: testutils.CreateMockICMPPacket(nil, icmpLayer, nil, nil, false), | ||
| expected: nil, | ||
| errMsg: "failed to decode inner ICMP payload", | ||
| }, | ||
| { | ||
| description: "ICMP packet with partial TCP header should create icmpResponse", | ||
| inHeader: ipv4Header, | ||
| inPayload: testutils.CreateMockICMPPacket(nil, icmpLayer, innerIPv4Layer, innerTCPLayer, true), | ||
| expected: &ICMPResponse{ | ||
| SrcIP: srcIP, | ||
| DstIP: dstIP, | ||
| InnerSrcIP: innerSrcIP, | ||
| InnerDstIP: innerDstIP, | ||
| InnerSrcPort: 12345, | ||
| InnerDstPort: 443, | ||
| InnerSeqNum: 28394, | ||
| }, | ||
| errMsg: "", | ||
| }, | ||
| { | ||
| description: "full ICMP packet should create icmpResponse", | ||
| inHeader: ipv4Header, | ||
| inPayload: testutils.CreateMockICMPPacket(nil, icmpLayer, innerIPv4Layer, innerTCPLayer, true), | ||
| expected: &ICMPResponse{ | ||
| SrcIP: srcIP, | ||
| DstIP: dstIP, | ||
| InnerSrcIP: innerSrcIP, | ||
| InnerDstIP: innerDstIP, | ||
| InnerSrcPort: 12345, | ||
| InnerDstPort: 443, | ||
| InnerSeqNum: 28394, | ||
| }, | ||
| errMsg: "", | ||
| }, | ||
| } | ||
|
|
||
| for _, test := range tt { | ||
| t.Run(test.description, func(t *testing.T) { | ||
| actual, err := ParseICMP(test.inHeader, test.inPayload) | ||
| if test.errMsg != "" { | ||
| require.Error(t, err) | ||
| assert.Contains(t, err.Error(), test.errMsg) | ||
| assert.Nil(t, actual) | ||
| return | ||
| } | ||
| require.Nil(t, err) | ||
| require.NotNil(t, actual) | ||
| // assert.Equal doesn't handle net.IP well | ||
| assert.Equal(t, testutils.StructFieldCount(test.expected), testutils.StructFieldCount(actual)) | ||
| assert.Truef(t, test.expected.SrcIP.Equal(actual.SrcIP), "mismatch source IPs: expected %s, got %s", test.expected.SrcIP.String(), actual.SrcIP.String()) | ||
| assert.Truef(t, test.expected.DstIP.Equal(actual.DstIP), "mismatch dest IPs: expected %s, got %s", test.expected.DstIP.String(), actual.DstIP.String()) | ||
| assert.Truef(t, test.expected.InnerSrcIP.Equal(actual.InnerSrcIP), "mismatch inner source IPs: expected %s, got %s", test.expected.InnerSrcIP.String(), actual.InnerSrcIP.String()) | ||
| assert.Truef(t, test.expected.InnerDstIP.Equal(actual.InnerDstIP), "mismatch inner dest IPs: expected %s, got %s", test.expected.InnerDstIP.String(), actual.InnerDstIP.String()) | ||
| assert.Equal(t, test.expected.InnerSrcPort, actual.InnerSrcPort) | ||
| assert.Equal(t, test.expected.InnerDstPort, actual.InnerDstPort) | ||
| assert.Equal(t, test.expected.InnerSeqNum, actual.InnerSeqNum) | ||
| }) | ||
| } | ||
| } |
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