From 3f1edad4e6ba0a7876750aea55507fae14d8badf Mon Sep 17 00:00:00 2001
From: Milan Lenco <milan.lenco@pantheon.tech>
Date: Wed, 11 Oct 2017 16:40:58 +0200
Subject: ODPM 266: Go-libmemif + 2 examples.

Change-Id: Icdb9b9eb2314eff6c96afe7996fcf2728291de4a
Signed-off-by: Milan Lenco <milan.lenco@pantheon.tech>
---
 .../google/gopacket/dumpcommand/tcpdump.go         | 119 +++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 vendor/github.com/google/gopacket/dumpcommand/tcpdump.go

(limited to 'vendor/github.com/google/gopacket/dumpcommand/tcpdump.go')

diff --git a/vendor/github.com/google/gopacket/dumpcommand/tcpdump.go b/vendor/github.com/google/gopacket/dumpcommand/tcpdump.go
new file mode 100644
index 0000000..2d35722
--- /dev/null
+++ b/vendor/github.com/google/gopacket/dumpcommand/tcpdump.go
@@ -0,0 +1,119 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+// Package dumpcommand implements a run function for pfdump and pcapdump
+// with many similar flags/features to tcpdump.  This code is split out seperate
+// from data sources (pcap/pfring) so it can be used by both.
+package dumpcommand
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/ip4defrag"
+	"github.com/google/gopacket/layers" // pulls in all layers decoders
+)
+
+var (
+	print       = flag.Bool("print", true, "Print out packets, if false only prints out statistics")
+	maxcount    = flag.Int("c", -1, "Only grab this many packets, then exit")
+	decoder     = flag.String("decoder", "Ethernet", "Name of the decoder to use")
+	dump        = flag.Bool("X", false, "If true, dump very verbose info on each packet")
+	statsevery  = flag.Int("stats", 1000, "Output statistics every N packets")
+	printErrors = flag.Bool("errors", false, "Print out packet dumps of decode errors, useful for checking decoders against live traffic")
+	lazy        = flag.Bool("lazy", false, "If true, do lazy decoding")
+	defrag      = flag.Bool("defrag", false, "If true, do IPv4 defrag")
+)
+
+func Run(src gopacket.PacketDataSource) {
+	if !flag.Parsed() {
+		log.Fatalln("Run called without flags.Parse() being called")
+	}
+	var dec gopacket.Decoder
+	var ok bool
+	if dec, ok = gopacket.DecodersByLayerName[*decoder]; !ok {
+		log.Fatalln("No decoder named", *decoder)
+	}
+	source := gopacket.NewPacketSource(src, dec)
+	source.Lazy = *lazy
+	source.NoCopy = true
+	source.DecodeStreamsAsDatagrams = true
+	fmt.Fprintln(os.Stderr, "Starting to read packets")
+	count := 0
+	bytes := int64(0)
+	start := time.Now()
+	errors := 0
+	truncated := 0
+	layertypes := map[gopacket.LayerType]int{}
+	defragger := ip4defrag.NewIPv4Defragmenter()
+
+	for packet := range source.Packets() {
+		count++
+		bytes += int64(len(packet.Data()))
+
+		// defrag the IPv4 packet if required
+		if *defrag {
+			ip4Layer := packet.Layer(layers.LayerTypeIPv4)
+			if ip4Layer == nil {
+				continue
+			}
+			ip4 := ip4Layer.(*layers.IPv4)
+			l := ip4.Length
+
+			newip4, err := defragger.DefragIPv4(ip4)
+			if err != nil {
+				log.Fatalln("Error while de-fragmenting", err)
+			} else if newip4 == nil {
+				continue // packet fragment, we don't have whole packet yet.
+			}
+			if newip4.Length != l {
+				fmt.Printf("Decoding re-assembled packet: %s\n", newip4.NextLayerType())
+				pb, ok := packet.(gopacket.PacketBuilder)
+				if !ok {
+					panic("Not a PacketBuilder")
+				}
+				nextDecoder := newip4.NextLayerType()
+				nextDecoder.Decode(newip4.Payload, pb)
+			}
+		}
+
+		if *dump {
+			fmt.Println(packet.Dump())
+		} else if *print {
+			fmt.Println(packet)
+		}
+		if !*lazy || *print || *dump { // if we've already decoded all layers...
+			for _, layer := range packet.Layers() {
+				layertypes[layer.LayerType()]++
+			}
+			if packet.Metadata().Truncated {
+				truncated++
+			}
+			if errLayer := packet.ErrorLayer(); errLayer != nil {
+				errors++
+				if *printErrors {
+					fmt.Println("Error:", errLayer.Error())
+					fmt.Println("--- Packet ---")
+					fmt.Println(packet.Dump())
+				}
+			}
+		}
+		done := *maxcount > 0 && count >= *maxcount
+		if count%*statsevery == 0 || done {
+			fmt.Fprintf(os.Stderr, "Processed %v packets (%v bytes) in %v, %v errors and %v truncated packets\n", count, bytes, time.Since(start), errors, truncated)
+			if len(layertypes) > 0 {
+				fmt.Fprintf(os.Stderr, "Layer types seen: %+v\n", layertypes)
+			}
+		}
+		if done {
+			break
+		}
+	}
+}
-- 
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