Reformat code

analyze/analyzer.go

@@ -2,10 +2,11 @@ package analyze
 
 import (
 	"fmt"
+	"log"
+
+	"github.com/google/gopacket"
 	"github.com/maride/pancap/output"
 	"github.com/maride/pancap/protocol"
-	"github.com/google/gopacket"
-	"log"
 )
 
 var (
@@ -39,6 +40,9 @@ func Analyze(source *gopacket.PacketSource) error {
 			}
 		}
 
+		// Register communication for graph
+		output.AddPkgToGraph(packet)
+
 		// Raise statistics
 		totalPackets += 1
 		if processed {
@@ -68,4 +72,3 @@ func handleErr(err error) {
 		log.Printf("Encountered error while examining packets, continuing anyway. Error: %s", err.Error())
 	}
 }
-

file.go

@@ -3,29 +3,30 @@ package main
 import (
 	"flag"
 	"fmt"
+
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/google/gopacket/pcap"
 )
 
 var (
-	filenameFlag *string
+	filenameFlag string
 )
 
 // Registers the flag --file
 func registerFileFlags() {
-	filenameFlag = flag.String("file", "", "PCAP file to base analysis on")
+	flag.StringVar(&filenameFlag, "file", "", "PCAP file to base analysis on")
 }
 
 // Opens the PCAP, returns its packets and the link type or an error
 func openPCAP() (*gopacket.PacketSource, layers.LinkType, error) {
 	// Check if we even got a file.
-	if *filenameFlag == "" {
+	if filenameFlag == "" {
 		return nil, 0, fmt.Errorf("missing file to analyze. Please specifiy it with --file")
 	}
 
 	// Open specified file
-	handle, openErr := pcap.OpenOffline(*filenameFlag)
+	handle, openErr := pcap.OpenOffline(filenameFlag)
 	if openErr != nil {
 		// There were some problems opening the file
 		return nil, 0, openErr

main.go

@@ -3,11 +3,12 @@ package main
 import (
 	"flag"
 	"fmt"
-	"github.com/maride/pancap/analyze"
-	"github.com/maride/pancap/output"
 	"log"
 	"math/rand"
 	"time"
+
+	"github.com/maride/pancap/analyze"
+	"github.com/maride/pancap/output"
 )
 
 func main() {
@@ -36,6 +37,9 @@ func main() {
 	// Extract found and requested files
 	output.StoreFiles()
 
+	// Create communication graph
+	output.CreateGraph()
+
 	// Show user analysis
 	analyze.PrintSummary()
 

output/filemanager.go

@@ -46,12 +46,12 @@ func StoreFiles() {
 	var filesToExtract []File
 
 	// Check different flag scenarios
-	if *targetAllFiles {
+	if targetAllFiles {
 		// We should extract all files.
 		filesToExtract = registeredFiles
 	} else {
 		// We should extract only a given set of files
-		fileList := strings.Split(*targetFiles, ",")
+		fileList := strings.Split(targetFiles, ",")
 		for _, f := range fileList {
 			// Iterate over desired files
 			found := false
@@ -80,7 +80,7 @@ func StoreFiles() {
 
 // Writes the given file object to disk, along with a stats file placed next to it.
 func writeOut(f File) {
-	targetName := fmt.Sprintf("%s%c%s", *targetOutput, os.PathSeparator, f.hash)
+	targetName := fmt.Sprintf("%s%c%s", targetOutput, os.PathSeparator, f.hash)
 	targetDescName := fmt.Sprintf("%s.info", targetName)
 	targetDescription := fmt.Sprintf("Filename: %s\nHash: %s\nOrigin: %s\nSize: %d", f.name, f.hash, f.origin, len(f.content))
 

output/flag.go

@@ -3,19 +3,19 @@ package output
 import "flag"
 
 var (
-	fullOutput *bool
+	fullOutput       bool
-	printEmptyBlocks *bool
+	printEmptyBlocks bool
-	targetFiles *string
+	targetFiles      string
-	targetAllFiles *bool
+	targetAllFiles   bool
-	targetOutput *string
+	targetOutput     string
+	graphOutput      string
 )
 
 func RegisterFlags() {
-	fullOutput = flag.Bool("full-output", false, "Show full output instead of limiting submodule output")
+	flag.BoolVar(&fullOutput, "full-output", false, "Show full output instead of limiting submodule output")
-	printEmptyBlocks = flag.Bool("print-empty-blocks", false, "Prints blocks (submodule output) even if the submodule doesn't have any content to print.")
+	flag.BoolVar(&printEmptyBlocks, "print-empty-blocks", false, "Prints blocks (submodule output) even if the submodule doesn't have any content to print.")
-	targetFiles = flag.String("extract-these", "", "Comma-separated list of files to extract.")
+	flag.StringVar(&targetFiles, "extract-these", "", "Comma-separated list of files to extract.")
-	targetAllFiles = flag.Bool("extract-all", false, "Extract all files found.")
+	flag.BoolVar(&targetAllFiles, "extract-all", false, "Extract all files found.")
-	targetOutput = flag.String("extract-to", "./extracted", "Directory to store extracted files in.")
+	flag.StringVar(&targetOutput, "extract-to", "./extracted", "Directory to store extracted files in.")
+	flag.StringVar(&graphOutput, "create-graph", "", "Create a Graphviz graph out of collected communication")
 }
-
-

output/graph.go

@@ -0,0 +1,103 @@
+package output
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"io/ioutil"
+
+	"github.com/google/gopacket"
+)
+
+var graphPkgs []GraphPkg
+
+// AddPkgToGraph adds the given packet as communication to the graph
+func AddPkgToGraph(pkg gopacket.Packet) {
+	// Only proceed if pkg contains a network layer
+	if pkg.NetworkLayer() == nil {
+		return
+	}
+
+	src := pkg.NetworkLayer().NetworkFlow().Src().String()
+	dst := pkg.NetworkLayer().NetworkFlow().Dst().String()
+
+	// Search for the given communication pair
+	for _, p := range graphPkgs {
+		if p.from == src && p.to == dst {
+			// Communication pair found, add protocol and finish
+			p.AddProtocol("nil")
+			return
+		}
+	}
+
+	// Communcation pair was not in graphPkgs, add to it
+	graphPkgs = append(graphPkgs, GraphPkg{
+		from:     src,
+		to:       dst,
+		protocol: []string{""},
+	})
+}
+
+// CreateGraph writes out a Graphviz digraph
+func CreateGraph() {
+	if graphOutput == "" {
+		// No graph requested
+		return
+	}
+
+	// Start with the Graphviz-specific header
+	dot := fmt.Sprintf("# Compile with `neato -Tpng %s > %s.png`\n", graphOutput, graphOutput)
+	dot += "digraph pancap {\n\toverlap = false;\n"
+
+	// First, gather all nodes as-is and write them out
+	dot += nodedef(graphPkgs)
+
+	// Iterate over communication
+	for _, p := range graphPkgs {
+		dot += fmt.Sprintf("\tn%s->n%s\n", hash(p.from), hash(p.to))
+	}
+
+	// Close
+	dot += "}\n"
+
+	// Write out
+	ioutil.WriteFile(graphOutput, []byte(dot), 0644)
+}
+
+// Creates a list of distinct nodes, Graphviz-compatible
+func nodedef(pkgs []GraphPkg) string {
+	output := ""
+	nodes := []string{}
+	for _, p := range graphPkgs {
+		// Check if src and dst are already present in nodes array
+		srcFound := false
+		dstFound := false
+		for _, n := range nodes {
+			if p.from == n {
+				srcFound = true
+			}
+			if p.to == n {
+				dstFound = true
+			}
+		}
+		if !srcFound {
+			// src not yet present, add to node list
+			nodes = append(nodes, p.from)
+		}
+		if !dstFound {
+			// dst not yet present, add to node list
+			nodes = append(nodes, p.to)
+		}
+	}
+
+	// Output Graphviz-compatible node definition
+	for _, n := range nodes {
+		// As the Graphviz charset for nodes is rather small, rely on hashes
+		output += fmt.Sprintf("\tn%s[label=\"%s\"]\n", hash(n), n)
+	}
+
+	return output
+}
+
+func hash(s string) string {
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(s)))[:6]
+}

output/graphpkg.go

@@ -0,0 +1,19 @@
+package output
+
+// GraphPkg resembles a directed communication from one address to another
+// It wraps up required information to draw a graph of the communication, including spoken protocols.
+type GraphPkg struct {
+	from     string
+	to       string
+	protocol []string
+}
+
+// AddProtocol adds the given protocol to the list of protocols if not already present
+func (p *GraphPkg) AddProtocol(protocol string) {
+	for _, p := range p.protocol {
+		if p == protocol {
+			return
+		}
+	}
+	p.protocol = append(p.protocol, protocol)
+}

output/output.go

@@ -23,4 +23,10 @@ func Finalize() {
 		// User avoided the files
 		printer.Println("Files found in stream. Add --extract-all or --extract-these <list> to extract them.")
 	}
+
+	// Check if something graph-worthy was collected
+	if graphOutput == "" && len(graphPkgs) > 0 {
+		// User didn't want a graph
+		printer.Println("To summarize the communcation flow with a Graphviz graph, specify --create-graph <out.dot>.")
+	}
 }

output/printer.go

@@ -2,8 +2,9 @@ package output
 
 import (
 	"fmt"
-	"github.com/fatih/color"
 	"strings"
+
+	"github.com/fatih/color"
 )
 
 const (
@@ -21,7 +22,7 @@ var (
 // If the content is longer than MaxContentLines, content is cut.
 func PrintBlock(headline string, content string) {
 	// Avoid printing empty blocks - at least if user didn't specify it otherwise
-	if len(content) == 0 && !*printEmptyBlocks {
+	if len(content) == 0 && !printEmptyBlocks {
 		// No content and we are not forced to print empty blocks, return
 		DidAvoidEmptyBlock = true
 		return
@@ -38,7 +39,7 @@ func PrintBlock(headline string, content string) {
 	}
 
 	// Cut to MaxContentLines if required
-	if !(*fullOutput) {
+	if !(fullOutput) {
 		// User states that they don't want to see the whole output - cut content.
 		content = cutContent(content)
 	}

protocol/arp/arp.go

@@ -2,10 +2,10 @@ package arp
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
-	"github.com/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
+	"github.com/maride/pancap/output"
 	"log"
 	"net"
 )

protocol/dhcpv4/dhcp.go

@@ -1,9 +1,9 @@
 package dhcpv4
 
 import (
-	"github.com/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/output"
 )
 
 type Protocol struct {

protocol/dhcpv4/dhcpResponse.go

@@ -6,4 +6,3 @@ type dhcpResponse struct {
 	serverMACAddr string
 	askedFor      bool
 }
-

protocol/dhcpv4/hostnames.go

@@ -2,8 +2,8 @@ package dhcpv4
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
 	"log"
 )
 

protocol/dhcpv4/request.go

@@ -2,8 +2,8 @@ package dhcpv4
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
 )
 
 // Processes the DHCP request packet handed over

protocol/dhcpv4/response.go

@@ -2,8 +2,8 @@ package dhcpv4
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
 	"log"
 )
 

protocol/dns/answer.go

@@ -2,8 +2,8 @@ package dns
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
 	"golang.org/x/net/publicsuffix"
 	"log"
 )

protocol/dns/dns.go

@@ -1,9 +1,9 @@
 package dns
 
 import (
-	"github.com/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/output"
 )
 
 type Protocol struct{}

protocol/dns/question.go

@@ -2,8 +2,8 @@ package dns
 
 import (
 	"fmt"
-	"github.com/maride/pancap/common"
 	"github.com/google/gopacket/layers"
+	"github.com/maride/pancap/common"
 	"golang.org/x/net/publicsuffix"
 	"log"
 )

protocol/http/http.go

@@ -1,11 +1,11 @@
 package http
 
 import (
-	"github.com/maride/pancap/common"
-	"github.com/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/google/gopacket/tcpassembly"
+	"github.com/maride/pancap/common"
+	"github.com/maride/pancap/output"
 )
 
 type Protocol struct {

protocol/http/httpResponseFactory.go

@@ -3,10 +3,10 @@ package http
 import (
 	"bufio"
 	"fmt"
-	"github.com/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/tcpassembly"
 	"github.com/google/gopacket/tcpassembly/tcpreader"
+	"github.com/maride/pancap/output"
 	"io"
 	"io/ioutil"
 	"net/http"