Move statistics to file.go, add dummy ethernet analyzer

src/analyzer.go

@@ -1,20 +1,23 @@
 package main
 
 import (
+	"errors"
+	"fmt"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
-	"log"
+	"./ethernet"
 )
 
 // Analyzes the given packet source
 func analyzePCAP(source *gopacket.PacketSource, linkType layers.LinkType) error {
-	log.Printf("PCAP capture link type is %s (ID %d)", getNameOfLinkType(linkType), linkType)
-	// TODO: maybe, just maybe, we wanna print more here than just the link type :)
-	_, _ = source, linkType
-	return nil
+	// Switch over link type to determine correct module to ask for analysis
+	switch linkType {
+	case layers.LinkTypeEthernet:
+		// Ethernet
+		return ethernet.Analyze(source)
 	}
 
-// Returns the name of the LinkType constant handed over
-func getNameOfLinkType(lt layers.LinkType) string {
-	return lt.String()
+	// if we reach this point, the given PCAP contains a link type we can't handle (yet).
+	errorMsg := fmt.Sprintf("Asked for link type %s (ID %d), but not supported by pancap. :( sorry!", linkType.String(), linkType)
+	return errors.New(errorMsg)
 }

src/ethernet/ethernet.go

@@ -0,0 +1,8 @@
+package ethernet
+
+import "github.com/google/gopacket"
+
+func Analyze(source *gopacket.PacketSource) error {
+	// Dummy
+	return nil
+}

src/file.go

@@ -5,6 +5,7 @@ import (
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/google/gopacket/pcap"
+	"log"
 )
 
 var (
@@ -25,6 +26,9 @@ func openPCAP() (*gopacket.PacketSource, layers.LinkType, error) {
 		return nil, 0, openErr
 	}
 
+	// Output basic information about this PCAP
+	log.Printf("PCAP capture link type is %s (ID %d)", handle.LinkType().String(), handle.LinkType())
+
 	// Open given handle as packet source and return it
 	packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
 	return packetSource, handle.LinkType(), nil