diff options
Diffstat (limited to 'main.go')
| -rw-r--r-- | main.go | 178 |
1 files changed, 79 insertions, 99 deletions
@@ -13,33 +13,33 @@ import ( "encoding/json" "flag" "fmt" - "github.com/golang/glog" - "github.com/olekukonko/tablewriter" "math/rand" "net" "os" - "runtime" "syscall" "time" + + "github.com/golang/glog" + "github.com/olekukonko/tablewriter" ) // // Command line flags // -var maxTtl *int = flag.Int("maxTtl", 30, "The maximum ttl to use") -var minTtl *int = flag.Int("minTtl", 1, "The ttl to start at") -var maxSrcPorts *int = flag.Int("maxSrcPorts", 256, "The maximum number of source ports to use") -var maxTime *int = flag.Int("maxTime", 60, "The time to run the process for") -var targetPort *int = flag.Int("targetPort", 22, "The target port to trace to") -var probeRate *int = flag.Int("probeRate", 96, "The probe rate per ttl layer") -var tosValue *int = flag.Int("tosValue", 140, "The TOS/TC to use in probes") -var numResolvers *int = flag.Int("numResolvers", 32, "The number of DNS resolver goroutines") -var addrFamily *string = flag.String("addrFamily", "ip4", "The address family (ip4/ip6) to use for testing") -var maxColumns *int = flag.Int("maxColumns", 4, "Maximum number of columns in report tables") -var showAll *bool = flag.Bool("showAll", false, "Show all paths, regardless of loss detection") -var srcAddr *string = flag.String("srcAddr", "", "The source address for pings, default to auto-discover") -var jsonOutput *bool = flag.Bool("jsonOutput", false, "Output raw JSON data") -var baseSrcPort *int = flag.Int("baseSrcPort", 32768, "The base source port to start probing from") +var maxTTL = flag.Int("maxTTL", 30, "The maximum ttl to use") +var minTTL = flag.Int("minTTL", 1, "The ttl to start at") +var maxSrcPorts = flag.Int("maxSrcPorts", 256, "The maximum number of source ports to use") +var maxTime = flag.Int("maxTime", 60, "The time to run the process for") +var targetPort = flag.Int("targetPort", 22, "The target port to trace to") +var probeRate = flag.Int("probeRate", 96, "The probe rate per ttl layer") +var tosValue = flag.Int("tosValue", 140, "The TOS/TC to use in probes") +var numResolvers = flag.Int("numResolvers", 32, "The number of DNS resolver goroutines") +var addrFamily = flag.String("addrFamily", "ip4", "The address family (ip4/ip6) to use for testing") +var maxColumns = flag.Int("maxColumns", 4, "Maximum number of columns in report tables") +var showAll = flag.Bool("showAll", false, "Show all paths, regardless of loss detection") +var srcAddr = flag.String("srcAddr", "", "The source address for pings, default to auto-discover") +var jsonOutput = flag.Bool("jsonOutput", false, "Output raw JSON data") +var baseSrcPort = flag.Int("baseSrcPort", 32768, "The base source port to start probing from") // // Discover the source address for pinging @@ -68,50 +68,40 @@ func getSourceAddr(af string, srcAddr string) (*net.IP, error) { return nil, fmt.Errorf("Could not find a source address in af %s", af) } -// // Resolve given hostname/address in the given address family -// func resolveName(dest string, af string) (*net.IP, error) { addr, err := net.ResolveIPAddr(af, dest) return &addr.IP, err } -// -// Probe specification, emitted by sender -// +// Probe is emitted by sender type Probe struct { srcPort int ttl int } -// -// Emitted by IcmpReceiver -// -type IcmpResponse struct { +// ICMPResponse is emitted by ICMPReceiver +type ICMPResponse struct { Probe fromAddr *net.IP fromName string rtt uint32 } -// -// Emitted by TcpReceiver -// -type TcpResponse struct { +// TCPResponse is emitted by TCPReceiver +type TCPResponse struct { Probe rtt uint32 } -// -// Feed on TCP RST messages we receive from the end host; we use lots of parameters to check if the incoming packet -// is actually a response to our probe. We create TcpResponse structs and emit them on the output channel -// -func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortStart, probePortEnd, targetPort, maxTtl int) (chan interface{}, error) { +// TCPReceiver Feeds on TCP RST messages we receive from the end host; we use lots of parameters to check if the incoming packet +// is actually a response to our probe. We create TCPResponse structs and emit them on the output channel +func TCPReceiver(done <-chan struct{}, af string, targetAddr string, probePortStart, probePortEnd, targetPort, maxTTL int) (chan interface{}, error) { var recvSocket int var err error var ipHdrSize int - glog.V(2).Infoln("TcpReceiver starting...") + glog.V(2).Infoln("TCPReceiver starting...") // create the socket switch { @@ -131,11 +121,11 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt return nil, err } - // we'll be writing the TcpResponse structs to this channel + // we'll be writing the TCPResponse structs to this channel out := make(chan interface{}) // IP + TCP header, this channel is fed from the socket - recv := make(chan TcpResponse) + recv := make(chan TCPResponse) go func() { const tcpHdrSize int = 20 packet := make([]byte, ipHdrSize+tcpHdrSize) @@ -153,7 +143,7 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt } // is that from the target port we expect? - tcpHdr := parseTcpHeader(packet[ipHdrSize:n]) + tcpHdr := parseTCPHeader(packet[ipHdrSize:n]) if int(tcpHdr.Source) != targetPort { continue } @@ -181,7 +171,7 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt ackNum := tcpHdr.AckNum - 1 ttl := int(ackNum >> 24) - if ttl > maxTtl || ttl < 1 { + if ttl > maxTTL || ttl < 1 { continue } @@ -195,7 +185,7 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt continue } - recv <- TcpResponse{Probe: Probe{srcPort: int(tcpHdr.Destination), ttl: ttl}, rtt: now - ts} + recv <- TCPResponse{Probe: Probe{srcPort: int(tcpHdr.Destination), ttl: ttl}, rtt: now - ts} } }() @@ -207,7 +197,7 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt case response := <-recv: out <- response case <-done: - glog.V(2).Infoln("TcpReceiver terminating...") + glog.V(2).Infoln("TCPReceiver terminating...") return } } @@ -216,14 +206,12 @@ func TcpReceiver(done <-chan struct{}, af string, targetAddr string, probePortSt return out, nil } -// -// This runs on its own collecting Icmp responses until its explicitly told to stop -// -func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { +// ICMPReceiver runs on its own collecting ICMP responses until its explicitly told to stop +func ICMPReceiver(done <-chan struct{}, af string) (chan interface{}, error) { var recvSocket int var err error - var outerIpHdrSize int - var innerIpHdrSize int + var outerIPHdrSize int + var innerIPHdrSize int var icmpMsgType byte const ( @@ -235,17 +223,17 @@ func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { case af == "ip4": recvSocket, err = syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, syscall.IPPROTO_ICMP) // IPv4 raw socket always prepend the transport IPv4 header - outerIpHdrSize = 20 + outerIPHdrSize = 20 // the size of the original IPv4 header that was on the TCP packet sent out - innerIpHdrSize = 20 + innerIPHdrSize = 20 // hardcoded: time to live exceeded icmpMsgType = 11 case af == "ip6": recvSocket, err = syscall.Socket(syscall.AF_INET6, syscall.SOCK_RAW, syscall.IPPROTO_ICMPV6) // IPv6 raw socket does not prepend the original transport IPv6 header - outerIpHdrSize = 0 + outerIPHdrSize = 0 // this is the size of IPv6 header of the original TCP packet we used in the probes - innerIpHdrSize = 40 + innerIPHdrSize = 40 // time to live exceeded icmpMsgType = 3 } @@ -254,28 +242,28 @@ func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { return nil, err } - glog.V(2).Infoln("IcmpReceiver is starting...") + glog.V(2).Infoln("ICMPReceiver is starting...") recv := make(chan interface{}) go func() { // TODO: remove hardcode; 20 bytes for IP header, 8 bytes for ICMP header, 8 bytes for TCP header - packet := make([]byte, outerIpHdrSize+icmpHdrSize+innerIpHdrSize+tcpHdrSize) + packet := make([]byte, outerIPHdrSize+icmpHdrSize+innerIPHdrSize+tcpHdrSize) for { n, from, err := syscall.Recvfrom(recvSocket, packet, 0) if err != nil { break } // extract the 8 bytes of the original TCP header - if n < outerIpHdrSize+icmpHdrSize+innerIpHdrSize+tcpHdrSize { + if n < outerIPHdrSize+icmpHdrSize+innerIPHdrSize+tcpHdrSize { continue } // not ttl exceeded - if packet[outerIpHdrSize] != icmpMsgType || packet[outerIpHdrSize+1] != 0 { + if packet[outerIPHdrSize] != icmpMsgType || packet[outerIPHdrSize+1] != 0 { continue } - glog.V(4).Infof("Received icmp response message %d: %x\n", len(packet), packet) - tcpHdr := parseTcpHeader(packet[outerIpHdrSize+icmpHdrSize+innerIpHdrSize : n]) + glog.V(4).Infof("Received ICMP response message %d: %x\n", len(packet), packet) + tcpHdr := parseTCPHeader(packet[outerIPHdrSize+icmpHdrSize+innerIPHdrSize : n]) var fromAddr net.IP @@ -293,7 +281,7 @@ func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { ts := tcpHdr.SeqNum & 0x00ffffff // scale the current time now := uint32(time.Now().UnixNano()/(1000*1000)) & 0x00ffffff - recv <- IcmpResponse{Probe: Probe{srcPort: int(tcpHdr.Source), ttl: ttl}, fromAddr: &fromAddr, rtt: now - ts} + recv <- ICMPResponse{Probe: Probe{srcPort: int(tcpHdr.Source), ttl: ttl}, fromAddr: &fromAddr, rtt: now - ts} } }() @@ -303,11 +291,11 @@ func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { defer close(out) for { select { - // read Icmp struct + // read ICMP struct case response := <-recv: out <- response case <-done: - glog.V(2).Infoln("IcmpReceiver done") + glog.V(2).Infoln("ICMPReceiver done") return } } @@ -316,10 +304,8 @@ func IcmpReceiver(done <-chan struct{}, af string) (chan interface{}, error) { return out, nil } -// -// Resolve names in incoming IcmpResponse messages +// Resolver resolves names in incoming ICMPResponse messages // Everything else is passed through as is -// func Resolver(input chan interface{}) (chan interface{}, error) { out := make(chan interface{}) go func() { @@ -327,8 +313,8 @@ func Resolver(input chan interface{}) (chan interface{}, error) { for val := range input { switch val.(type) { - case IcmpResponse: - resp := val.(IcmpResponse) + case ICMPResponse: + resp := val.(ICMPResponse) names, err := net.LookupAddr(resp.fromAddr.String()) if err != nil { resp.fromName = "?" @@ -344,11 +330,9 @@ func Resolver(input chan interface{}) (chan interface{}, error) { return out, nil } -// -// Generate TCP SYN packet probes with given TTL at given packet per second rate +// Sender generates TCP SYN packet probes with given TTL at given packet per second rate // The packet descriptions are published to the output channel as Probe messages // As a side effect, the packets are injected into raw socket -// func Sender(done <-chan struct{}, srcAddr *net.IP, af, dest string, dstPort, baseSrcPort, maxSrcPorts, maxIters, ttl, pps, tos int) (chan interface{}, error) { var err error @@ -427,7 +411,7 @@ func Sender(done <-chan struct{}, srcAddr *net.IP, af, dest string, dstPort, bas probe := Probe{srcPort: srcPort, ttl: ttl} now := uint32(time.Now().UnixNano()/(1000*1000)) & 0x00ffffff seqNum := ((uint32(ttl) & 0xff) << 24) | (now & 0x00ffffff) - packet := makeTcpHeader(af, srcAddr, dstAddr, srcPort, dstPort, seqNum) + packet := makeTCPHeader(af, srcAddr, dstAddr, srcPort, dstPort, seqNum) switch { case af == "ip4": @@ -510,16 +494,16 @@ func isLossy(hitRates []float64) bool { // // print the paths reported as having losses // -func printLossyPaths(sent, rcvd map[int] /* src port */ []int, hops map[int] /* src port */ []string, maxColumns, maxTtl int) { +func printLossyPaths(sent, rcvd map[int] /* src port */ []int, hops map[int] /* src port */ []string, maxColumns, maxTTL int) { var allPorts []int - for srcPort, _ := range hops { + for srcPort := range hops { allPorts = append(allPorts, srcPort) } // split in multiple tables to fit the columns on the screen for i := 0; i < len(allPorts)/maxColumns; i++ { - data := make([][]string, maxTtl) + data := make([][]string, maxTTL) table := tablewriter.NewWriter(os.Stdout) header := []string{"TTL"} @@ -534,7 +518,7 @@ func printLossyPaths(sent, rcvd map[int] /* src port */ []int, hops map[int] /* table.SetHeader(header) - for ttl := 0; ttl < maxTtl-1; ttl++ { + for ttl := 0; ttl < maxTTL-1; ttl++ { data[ttl] = make([]string, 2*(maxOffset-i*maxColumns)+1) data[ttl][0] = fmt.Sprintf("%d", ttl+1) for j, srcPort := range allPorts[i*maxColumns : maxOffset] { @@ -552,9 +536,7 @@ func printLossyPaths(sent, rcvd map[int] /* src port */ []int, hops map[int] /* } } -// -// Define a JSON report from go/fbtracert -// +// Report defines a JSON report from go/fbtracert type Report struct { // The path map Paths map[string] /* srcPort */ []string /* path hops */ @@ -575,7 +557,7 @@ func newReport() (report Report) { // // Raw Json output for external program to analyze // -func printLossyPathsJson(sent, rcvd map[int] /* src port */ []int, hops map[int] /* src port */ []string, maxTtl int) { +func printLossyPathsJSON(sent, rcvd map[int] /* src port */ []int, hops map[int] /* src port */ []string, maxTTL int) { var report = newReport() for srcPort, path := range hops { @@ -593,8 +575,6 @@ func printLossyPathsJson(sent, rcvd map[int] /* src port */ []int, hops map[int] } func main() { - runtime.GOMAXPROCS(runtime.NumCPU()) - flag.Parse() if flag.Arg(0) == "" { fmt.Fprintf(os.Stderr, "Must specify a target\n") @@ -622,12 +602,12 @@ func main() { fmt.Fprintf(os.Stderr, "Use '-logtostderr=true' cmd line option to see GLOG output\n") // this will catch senders quitting - we have one sender per ttl - senderDone := make([]chan struct{}, *maxTtl) - for ttl := *minTtl; ttl <= *maxTtl; ttl++ { + senderDone := make([]chan struct{}, *maxTTL) + for ttl := *minTTL; ttl <= *maxTTL; ttl++ { senderDone[ttl-1] = make(chan struct{}) c, err := Sender(senderDone[ttl-1], source, *addrFamily, target, *targetPort, *baseSrcPort, *maxSrcPorts, numIters, ttl, *probeRate, *tosValue) if err != nil { - glog.Fatalf("Failed to start sender for ttl %d, %s\n", ttl, err) + glog.Fatalf("Failed to start sender for ttl %d, %s\n -- are you running with the correct privileges?", ttl, err) return } probes = append(probes, c) @@ -636,15 +616,15 @@ func main() { // channel to tell receivers to stop recvDone := make(chan struct{}) - // collect icmp unreachable messages for our probes - icmpResp, err := IcmpReceiver(recvDone, *addrFamily) + // collect ICMP unreachable messages for our probes + icmpResp, err := ICMPReceiver(recvDone, *addrFamily) if err != nil { return } // collect TCP RST's from the target targetAddr, err := resolveName(target, *addrFamily) - tcpResp, err := TcpReceiver(recvDone, *addrFamily, targetAddr.String(), *baseSrcPort, *baseSrcPort+*maxSrcPorts, *targetPort, *maxTtl) + tcpResp, err := TCPReceiver(recvDone, *addrFamily, targetAddr.String(), *baseSrcPort, *baseSrcPort+*maxSrcPorts, *targetPort, *maxTTL) if err != nil { return } @@ -669,12 +649,12 @@ func main() { hops := make(map[int] /*src Port */ []string /* hop name */) for srcPort := *baseSrcPort; srcPort < *baseSrcPort+*maxSrcPorts; srcPort++ { - sent[srcPort] = make([]int, *maxTtl) - rcvd[srcPort] = make([]int, *maxTtl) - hops[srcPort] = make([]string, *maxTtl) - //hops[srcPort][*maxTtl-1] = target + sent[srcPort] = make([]int, *maxTTL) + rcvd[srcPort] = make([]int, *maxTTL) + hops[srcPort] = make([]string, *maxTTL) + //hops[srcPort][*maxTTL-1] = target - for i := 0; i < *maxTtl; i++ { + for i := 0; i < *maxTTL; i++ { hops[srcPort][i] = "?" } } @@ -697,13 +677,13 @@ func main() { var names []string // src ports that changed their paths in process of tracing - var flappedPorts map[int]bool = make(map[int]bool) + var flappedPorts = make(map[int]bool) - lastClosed := *maxTtl + lastClosed := *maxTTL for val := range merge(resolved...) { switch val.(type) { - case IcmpResponse: - resp := val.(IcmpResponse) + case ICMPResponse: + resp := val.(ICMPResponse) rcvd[resp.srcPort][resp.ttl-1]++ currName := hops[resp.srcPort][resp.ttl-1] if currName != "?" && currName != resp.fromName { @@ -715,8 +695,8 @@ func main() { // XXX: we may have duplicates, which is OK, // but not very efficient names = append(names, resp.fromName) - case TcpResponse: - resp := val.(TcpResponse) + case TCPResponse: + resp := val.(TCPResponse) // stop all senders sending above this ttl, since they are not needed // XXX: this is not always optimal, i.e. we may receive TCP RST for // a port mapped to a short WAN path, and it would tell us to terminate @@ -737,7 +717,7 @@ func main() { for srcPort, hopVector := range hops { for i := range hopVector { // truncate lists once we hit the target name - if hopVector[i] == target && i < *maxTtl-1 { + if hopVector[i] == target && i < *maxTTL-1 { sent[srcPort] = sent[srcPort][:i+1] rcvd[srcPort] = rcvd[srcPort][:i+1] hopVector = hopVector[:i+1] @@ -783,7 +763,7 @@ func main() { if len(lossyPathHops) > 0 { if *jsonOutput { - printLossyPathsJson(lossyPathSent, lossyPathRcvd, lossyPathHops, lastClosed+1) + printLossyPathsJSON(lossyPathSent, lossyPathRcvd, lossyPathHops, lastClosed+1) } else { printLossyPaths(lossyPathSent, lossyPathRcvd, lossyPathHops, *maxColumns, lastClosed+1) } |