From 46a1ad4ed08309ede6a612b674f0b9c71e1e4119 Mon Sep 17 00:00:00 2001
From: Aaron Turner <synfinatic@gmail.com>
Date: Thu, 15 Oct 2020 20:53:31 -0700
Subject: [PATCH] Add str2pcap tool for taking debug logs and making a pcap

Super basic right now.  Need to add unit tests & actually parse the log?
---
 CHANGELOG.md     |  1 +
 Makefile         |  9 +++++-
 str2pcap/main.go | 74 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 str2pcap/main.go

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26c4ece..f853f46 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 Added:
 
 - Support for Wireguard (LinkType RAW) interfaces #29
+- Add str2pcap for improved debugging of logs
 
 ## v0.0.4 - 02-10-2020
 
diff --git a/Makefile b/Makefile
index 6b883dc..c9da4d5 100644
--- a/Makefile
+++ b/Makefile
@@ -23,8 +23,15 @@ BUILDINFOS         := $(shell date +%FT%T%z)$(BUILDINFOSDET)
 HOSTNAME           := $(shell hostname)
 LDFLAGS            := -X "main.Version=$(PROJECT_VERSION)" -X "main.Buildinfos=$(BUILDINFOS)" -X "main.Tag=$(PROJECT_TAG)" -X "main.CommitID=$(PROJECT_COMMIT)"
 OUTPUT_NAME        := $(DIST_DIR)$(PROJECT_NAME)-$(PROJECT_VERSION)-$(GOOS)-$(GOARCH)
+STR2PCAP_NAME      := $(DIST_DIR)str2pcap-$(PROJECT_VERSION)-$(GOOS)-$(GOARCH)
 
-ALL: $(OUTPUT_NAME) ## Build binary
+
+ALL: $(OUTPUT_NAME) str2pcap ## Build binary
+
+str2pcap: $(STR2PCAP_NAME)
+
+$(STR2PCAP_NAME): str2pcap/*.go
+	go build -o $(STR2PCAP_NAME) str2pcap/*.go
 
 include help.mk  # place after ALL target and before all other targets
 
diff --git a/str2pcap/main.go b/str2pcap/main.go
new file mode 100644
index 0000000..ac27eaa
--- /dev/null
+++ b/str2pcap/main.go
@@ -0,0 +1,74 @@
+package main
+
+// Code to take a file with each line representing a packet in hex
+// Intended to be used with the log output from udp-proxy-2020
+
+import (
+	"bufio"
+	"encoding/hex"
+	"os"
+	"time"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcapgo"
+	log "github.com/sirupsen/logrus"
+	flag "github.com/spf13/pflag"
+)
+
+func main() {
+	var out = flag.String("out", "", "Pcap file to create")
+	var in = flag.String("in", "", "Input file name with packet data to read")
+	var dlt = flag.Uint8("dlt", 1, "DLT value")
+	var debug = flag.Bool("debug", false, "Enable debugging")
+
+	flag.Parse()
+	if *debug == true {
+		log.SetReportCaller(true)
+		log.SetLevel(log.DebugLevel)
+	} else {
+		log.SetLevel(log.WarnLevel)
+	}
+
+	if len(*out) == 0 || len(*in) == 0 {
+		log.Fatal("Please specify --in, --out and --dlt")
+	}
+
+	infile, err := os.Open(*in)
+	if err != nil {
+		log.Fatalf("--in %s: %s", *in, err)
+	}
+	inScanner := bufio.NewScanner(infile)
+	inScanner.Split(bufio.ScanLines)
+
+	fh, err := os.Create(*out)
+	if err != nil {
+		log.Fatalf("--out %s: %s", *out, err)
+	}
+
+	var linktype = layers.LinkType(*dlt)
+	pcap := pcapgo.NewWriterNanos(fh)
+	pcap.WriteFileHeader(65535, linktype)
+	var i = 0
+	for inScanner.Scan() {
+		i += 1
+		bytes, err := hex.DecodeString(inScanner.Text())
+		if err != nil {
+			log.Fatalf("reading line %d: %s", i, err)
+		}
+
+		ci := gopacket.CaptureInfo{
+			Timestamp:      time.Time{},
+			CaptureLength:  len(bytes),
+			Length:         len(bytes),
+			InterfaceIndex: 0,
+		}
+		err = pcap.WritePacket(ci, bytes)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	infile.Close()
+	// no method to close a gopcap Writer???? WTF?
+}