Start trying to make it a library

examples/simple/simple.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"github.com/dirtbags/netshovel"
+)
+
+struct SimpleStreamFactory {
+	netshovel.Factory
+}
+
+struct SimpleStream {
+	netshovel.Stream
+}
+
+func (f *SimpleStreamFactory) New(net, transport gopacket.Flow) tcpassembly.Stream {
+	ret = SimpleStream{}
+	ret.Stream = f.Factory.New(net, transport)
+}
+
+struct SimplePacket {
+	netshovel.Packet
+}
+
+func main() {
+	netshovel.Shovel(SimpleFactory)
+}

netshovel.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+	"github.com/dirtbags/netshovel/gapstring"
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+	"github.com/google/gopacket/tcpassembly"
+)
+
+
+func Shovel(factory tcpassembly.StreamFactory) {
+	verbose := flag.Bool("verbose", false, "Write lots of information out")
+	flag.Parse()
+	
+	streamPool := tcpassembly.NewStreamPool(factory)
+	assembler := tcpassembly.NewAssembler(streamPool)
+	
+	for _, fn := range flag.Args() {
+		handle, err := pcap.OpenOffline(fn)
+		if err != nil {
+			log.Fatal(err)
+		}
+		
+		packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
+		packets := packetSource.Packets()
+		npackets := 0
+		for packet := range packets {
+			if packet == nil {
+				break
+			}
+			if packet.NetworkLayer() == nil || packet.TransportLayer() == nil || packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
+				log.Println("Unusable packet")
+				continue
+			}
+			tcp := packet.TransportLayer().(*layers.TCP)
+			assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, packet.Metadata().Timestamp)
+			npackets += 1
+		}
+		log.Println("npackets", npackets)
+	}
+	assembler.FlushAll()
+	goRoutines.Wait()
+}

packet.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+	"github.com/dirtbags/netshovel/gapstring"
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+	"github.com/google/gopacket/tcpassembly"
+)
+
+type Packet struct {
+	Opcode int
+	Description string
+	When time.Time
+	Payload gapstring.GapString
+	Fields map[string]string
+}
+
+var never = time.Unix(0, 0)
+
+func NewPacket() Packet {
+	return Packet{
+		Opcode: -1,
+		Description: "Undefined",
+		When: never,
+		Payload: gapstring.GapString{},
+		Fields: map[string]string{},
+	}
+}
+
+func (pkt *Packet) Name() string {
+	return "Generic"
+}
+
+func (pkt *Packet) Describe() string {
+	out := new(strings.Builder)
+
+	fmt.Fprintf(out, "%s %s %d: %s\n",
+	  pkt.When.UTC().Format(tim.RFC3339Nano),
+		pkt.Name(),
+		pkt.Opcode,
+		pkt.Description,
+	)
+	for _, k := range pkt.Keys() {
+		fmt.Fprintf(out, "      %s: %s\n", k, pkt.Fields[k])
+	}
+	fmt.Fprint(out, pkt.Payload.Hexdump())
+	return out.String()
+}
+
+func (pkt *Packet) Set(key, value string) {
+	pkt.Fileds[key] = value
+}
+
+func (pkt *Packet) Keys() {
+	keys := make([]string, len(pkt.Fields))
+	i := 0
+	for k := range(pkt.Fields) {
+		keys[i] = k
+		i += 1
+	}
+	sort.Strings(keys)
+	return keys
+}

stream.go

@@ -16,9 +16,7 @@ import (
 	"github.com/google/gopacket/tcpassembly"
 )
 
-var verbose = flag.Bool("verbose", false, "Write lots of information out")
-
-var goRoutines sync.WaitGroup
+var StreamWG sync.WaitGroup
 
 type WriteAtCloser interface {
 	io.WriterAt
@@ -39,34 +37,14 @@ type Stream struct {
 	pending Utterance
 }
 
-type Packet struct {
-	Opcode int
-	Description string
-	When time.Time
-	Payload gapstring.GapString
-	Fields map[string]string
-}
-
-var noTime = time.Unix(0, 0)
-
-func NewPacket() Packet {
-	return Packet{
-		Opcode: -1,
-		Description: "Undefined",
-		When: noTime,
-		Payload: gapstring.GapString{},
-		Fields: map[string]string{},
-	}
-}
-
 func (f *StreamFactory) New(net, transport gopacket.Flow) tcpassembly.Stream {
 	stream := &Stream{
 		Net: net,
 		Transport: transport,
 		conversation: make(chan Utterance, 100),
 	}
-	goRoutines.Add(1)
-	go stream.run()
+	StreamWG.Add(1)
+	go stream.Run(StreamWG)
 	
 	return stream
 }
@@ -140,29 +118,18 @@ func (stream *Stream) Read(length int) (Utterance, error) {
 func (stream *Stream) Describe(pkt Packet) string {
 	out := new(strings.Builder)
 
-	fmt.Fprintf(out, "Opcode %d: %s\n", pkt.Opcode, pkt.Description)
-	fmt.Fprintf(out, "    %v:%v → %v:%v (%s)\n",
-              stream.Net.Src().String(), stream.Transport.Src().String(),
-              stream.Net.Dst().String(), stream.Transport.Dst().String(),
-              pkt.When.UTC().Format(time.RFC3339Nano))
-	keys := make([]string, len(pkt.Fields))
-	i := 0
-	for k := range(pkt.Fields) {
-		keys[i] = k
-		i += 1
-	}
-	sort.Strings(keys)
-	for _, k := range keys {
-		fmt.Fprintf(out, "      %s: %s\n", k, pkt.Fields[k])
-	}
-	fmt.Fprint(out, pkt.Payload.Hexdump())
+	fmt.Fprintf(out, "%v:%v → %v:%v\n",
+		stream.Net.Src().String(), stream.Transport.Src().String(),
+    stream.Net.Dst().String(), stream.Transport.Dst().String()
+  )
+  out.writeString(pkt.Describe())
 	return out.String()
 }
 
-func (stream *Stream) run() {
-	defer goRoutines.Done()
+func (stream *Stream) Run(wg sync.WaitGroup) {
+	defer wg.Done()
 	for {
-		pkt, err := stream.buildPacket()
+		pkt, err := stream.BuildPacket()
 		if err == io.EOF {
 			return
 		} else if err != nil {
@@ -174,7 +141,7 @@ func (stream *Stream) run() {
 	}
 }
 
-func (stream *Stream) buildPacket() (Packet, error) {
+func (stream *Stream) BuildPacket() (Packet, error) {
 	pkt := NewPacket()
 	
 	utterance, err := stream.Read(-1)
@@ -186,37 +153,3 @@ func (stream *Stream) buildPacket() (Packet, error) {
 	pkt.When = utterance.When
 	return pkt, nil
 }
-
-func main() {
-	flag.Parse()
-	
-	streamFactory := &StreamFactory{}
-	streamPool := tcpassembly.NewStreamPool(streamFactory)
-	assembler := tcpassembly.NewAssembler(streamPool)
-	
-	for _, fn := range flag.Args() {
-		handle, err := pcap.OpenOffline(fn)
-		if err != nil {
-			log.Fatal(err)
-		}
-		
-		packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
-		packets := packetSource.Packets()
-		npackets := 0
-		for packet := range packets {
-			if packet == nil {
-				break
-			}
-			if packet.NetworkLayer() == nil || packet.TransportLayer() == nil || packet.TransportLayer().LayerType() != layers.LayerTypeTCP {
-				log.Println("Unusable packet")
-				continue
-			}
-			tcp := packet.TransportLayer().(*layers.TCP)
-			assembler.AssembleWithTimestamp(packet.NetworkLayer().NetworkFlow(), tcp, packet.Metadata().Timestamp)
-			npackets += 1
-		}
-		log.Println("npackets", npackets)
-	}
-	assembler.FlushAll()
-	goRoutines.Wait()
-}