[windows][network path] Add windows support for traceroute

pkg/networkpath/traceroute/tcp/tcpv4.go

@@ -7,14 +7,9 @@
 package tcp
 
 import (
-	"fmt"
-	"math/rand"
 	"net"
 	"time"
 
-	"golang.org/x/net/ipv4"
-
-	"github.com/DataDog/datadog-agent/pkg/util/log"
 	"github.com/google/gopacket/layers"
 )
 
@@ -54,113 +49,6 @@ type (
 	}
 )
 
-// TracerouteSequential runs a traceroute sequentially where a packet is
-// sent and we wait for a response before sending the next packet
-func (t *TCPv4) TracerouteSequential() (*Results, error) {
-	// Get local address for the interface that connects to this
-	// host and store in in the probe
-	//
-	// TODO: do this once for the probe and hang on to the
-	// listener until we decide to close the probe
-	addr, err := localAddrForHost(t.Target, t.DestPort)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get local address for target: %w", err)
-	}
-	t.srcIP = addr.IP
-	t.srcPort = addr.AddrPort().Port()
-
-	// So far I haven't had success trying to simply create a socket
-	// using syscalls directly, but in theory doing so would allow us
-	// to avoid creating two listeners since we could see all IP traffic
-	// this way
-	//
-	// Create a raw ICMP listener to catch ICMP responses
-	icmpConn, err := net.ListenPacket("ip4:icmp", addr.IP.String())
-	if err != nil {
-		return nil, fmt.Errorf("failed to create ICMP listener: %w", err)
-	}
-	defer icmpConn.Close()
-	// RawConn is necessary to set the TTL and ID fields
-	rawIcmpConn, err := ipv4.NewRawConn(icmpConn)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get raw ICMP listener: %w", err)
-	}
-
-	// Create a raw TCP listener to catch the TCP response from our final
-	// hop if we get one
-	tcpConn, err := net.ListenPacket("ip4:tcp", addr.IP.String())
-	if err != nil {
-		return nil, fmt.Errorf("failed to create TCP listener: %w", err)
-	}
-	defer tcpConn.Close()
-	log.Tracef("Listening for TCP on: %s\n", addr.IP.String()+":"+addr.AddrPort().String())
-	// RawConn is necessary to set the TTL and ID fields
-	rawTCPConn, err := ipv4.NewRawConn(tcpConn)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get raw TCP listener: %w", err)
-	}
-
-	// hops should be of length # of hops
-	hops := make([]*Hop, 0, t.MaxTTL-t.MinTTL)
-
-	for i := int(t.MinTTL); i <= int(t.MaxTTL); i++ {
-		seqNumber := rand.Uint32()
-		hop, err := t.sendAndReceive(rawIcmpConn, rawTCPConn, i, seqNumber, t.Timeout)
-		if err != nil {
-			return nil, fmt.Errorf("failed to run traceroute: %w", err)
-		}
-		hops = append(hops, hop)
-		log.Tracef("Discovered hop: %+v", hop)
-		// if we've reached our destination,
-		// we're done
-		if hop.IsDest {
-			break
-		}
-	}
-
-	return &Results{
-		Source:     t.srcIP,
-		SourcePort: t.srcPort,
-		Target:     t.Target,
-		DstPort:    t.DestPort,
-		Hops:       hops,
-	}, nil
-}
-
-func (t *TCPv4) sendAndReceive(rawIcmpConn *ipv4.RawConn, rawTCPConn *ipv4.RawConn, ttl int, seqNum uint32, timeout time.Duration) (*Hop, error) {
-	tcpHeader, tcpPacket, err := createRawTCPSyn(t.srcIP, t.srcPort, t.Target, t.DestPort, seqNum, ttl)
-	if err != nil {
-		log.Errorf("failed to create TCP packet with TTL: %d, error: %s", ttl, err.Error())
-		return nil, err
-	}
-
-	err = sendPacket(rawTCPConn, tcpHeader, tcpPacket)
-	if err != nil {
-		log.Errorf("failed to send TCP SYN: %s", err.Error())
-		return nil, err
-	}
-
-	start := time.Now() // TODO: is this the best place to start?
-	hopIP, hopPort, icmpType, end, err := listenPackets(rawIcmpConn, rawTCPConn, timeout, t.srcIP, t.srcPort, t.Target, t.DestPort, seqNum)
-	if err != nil {
-		log.Errorf("failed to listen for packets: %s", err.Error())
-		return nil, err
-	}
-
-	rtt := time.Duration(0)
-	if !hopIP.Equal(net.IP{}) {
-		rtt = end.Sub(start)
-	}
-
-	return &Hop{
-		IP:       hopIP,
-		Port:     hopPort,
-		ICMPType: icmpType,
-		RTT:      rtt,
-		IsDest:   hopIP.Equal(t.Target),
-	}, nil
-}
-
 // Close doesn't to anything yet, but we should
 // use this to close out long running sockets
 // when we're done with a path test

pkg/networkpath/traceroute/tcp/tcpv4_linux.go

@@ -0,0 +1,125 @@
+// 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 tcp adds a TCP traceroute implementation to the agent
+package tcp
+
+import (
+	"fmt"
+	"math/rand"
+	"net"
+	"time"
+
+	"golang.org/x/net/ipv4"
+
+	"github.com/DataDog/datadog-agent/pkg/util/log"
+)
+
+// TracerouteSequential runs a traceroute sequentially where a packet is
+// sent and we wait for a response before sending the next packet
+func (t *TCPv4) TracerouteSequential() (*Results, error) {
+	// Get local address for the interface that connects to this
+	// host and store in in the probe
+	//
+	// TODO: do this once for the probe and hang on to the
+	// listener until we decide to close the probe
+	addr, err := localAddrForHost(t.Target, t.DestPort)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get local address for target: %w", err)
+	}
+	t.srcIP = addr.IP
+	t.srcPort = addr.AddrPort().Port()
+
+	// So far I haven't had success trying to simply create a socket
+	// using syscalls directly, but in theory doing so would allow us
+	// to avoid creating two listeners since we could see all IP traffic
+	// this way
+	//
+	// Create a raw ICMP listener to catch ICMP responses
+	icmpConn, err := net.ListenPacket("ip4:icmp", addr.IP.String())
+	if err != nil {
+		return nil, fmt.Errorf("failed to create ICMP listener: %w", err)
+	}
+	defer icmpConn.Close()
+	// RawConn is necessary to set the TTL and ID fields
+	rawIcmpConn, err := ipv4.NewRawConn(icmpConn)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get raw ICMP listener: %w", err)
+	}
+
+	// Create a raw TCP listener to catch the TCP response from our final
+	// hop if we get one
+	tcpConn, err := net.ListenPacket("ip4:tcp", addr.IP.String())
+	if err != nil {
+		return nil, fmt.Errorf("failed to create TCP listener: %w", err)
+	}
+	defer tcpConn.Close()
+	log.Tracef("Listening for TCP on: %s\n", addr.IP.String()+":"+addr.AddrPort().String())
+	// RawConn is necessary to set the TTL and ID fields
+	rawTCPConn, err := ipv4.NewRawConn(tcpConn)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get raw TCP listener: %w", err)
+	}
+
+	// hops should be of length # of hops
+	hops := make([]*Hop, 0, t.MaxTTL-t.MinTTL)
+
+	for i := int(t.MinTTL); i <= int(t.MaxTTL); i++ {
+		seqNumber := rand.Uint32()
+		hop, err := t.sendAndReceive(rawIcmpConn, rawTCPConn, i, seqNumber, t.Timeout)
+		if err != nil {
+			return nil, fmt.Errorf("failed to run traceroute: %w", err)
+		}
+		hops = append(hops, hop)
+		log.Tracef("Discovered hop: %+v", hop)
+		// if we've reached our destination,
+		// we're done
+		if hop.IsDest {
+			break
+		}
+	}
+
+	return &Results{
+		Source:     t.srcIP,
+		SourcePort: t.srcPort,
+		Target:     t.Target,
+		DstPort:    t.DestPort,
+		Hops:       hops,
+	}, nil
+}
+
+func (t *TCPv4) sendAndReceive(rawIcmpConn *ipv4.RawConn, rawTCPConn *ipv4.RawConn, ttl int, seqNum uint32, timeout time.Duration) (*Hop, error) {
+	tcpHeader, tcpPacket, err := createRawTCPSyn(t.srcIP, t.srcPort, t.Target, t.DestPort, seqNum, ttl)
+	if err != nil {
+		log.Errorf("failed to create TCP packet with TTL: %d, error: %s", ttl, err.Error())
+		return nil, err
+	}
+
+	err = sendPacket(rawTCPConn, tcpHeader, tcpPacket)
+	if err != nil {
+		log.Errorf("failed to send TCP SYN: %s", err.Error())
+		return nil, err
+	}
+
+	start := time.Now() // TODO: is this the best place to start?
+	hopIP, hopPort, icmpType, end, err := listenPackets(rawIcmpConn, rawTCPConn, timeout, t.srcIP, t.srcPort, t.Target, t.DestPort, seqNum)
+	if err != nil {
+		log.Errorf("failed to listen for packets: %s", err.Error())
+		return nil, err
+	}
+
+	rtt := time.Duration(0)
+	if !hopIP.Equal(net.IP{}) {
+		rtt = end.Sub(start)
+	}
+
+	return &Hop{
+		IP:       hopIP,
+		Port:     hopPort,
+		ICMPType: icmpType,
+		RTT:      rtt,
+		IsDest:   hopIP.Equal(t.Target),
+	}, nil
+}