src/cmd/nncp-pkt/main.go

   1 /*
   2 NNCP -- Node to Node copy, utilities for store-and-forward data exchange
   3 Copyright (C) 2016-2021 Sergey Matveev <stargrave@stargrave.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, version 3 of the License.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 // Parse raw NNCP packet.
  19 package main
  20
  21 import (
  22         "bufio"
  23         "bytes"
  24         "flag"
  25         "fmt"
  26         "io"
  27         "log"
  28         "os"
  29
  30         xdr "github.com/davecgh/go-xdr/xdr2"
  31         "github.com/klauspost/compress/zstd"
  32         "go.cypherpunks.ru/nncp/v6"
  33 )
  34
  35 func usage() {
  36         fmt.Fprintf(os.Stderr, nncp.UsageHeader())
  37         fmt.Fprintf(os.Stderr, "nncp-pkt -- parse raw packet\n\n")
  38         fmt.Fprintf(os.Stderr, "Usage: %s [options]\nOptions:\n", os.Args[0])
  39         flag.PrintDefaults()
  40         fmt.Fprintln(os.Stderr, "Packet is read from stdin.")
  41 }
  42
  43 func main() {
  44         var (
  45                 overheads  = flag.Bool("overheads", false, "Print packet overheads")
  46                 dump       = flag.Bool("dump", false, "Write decrypted/parsed payload to stdout")
  47                 decompress = flag.Bool("decompress", false, "Try to zstd decompress dumped data")
  48                 cfgPath    = flag.String("cfg", nncp.DefaultCfgPath, "Path to configuration file")
  49                 version    = flag.Bool("version", false, "Print version information")
  50                 warranty   = flag.Bool("warranty", false, "Print warranty information")
  51         )
  52         log.SetFlags(log.Lshortfile)
  53         flag.Usage = usage
  54         flag.Parse()
  55         if *warranty {
  56                 fmt.Println(nncp.Warranty)
  57                 return
  58         }
  59         if *version {
  60                 fmt.Println(nncp.VersionGet())
  61                 return
  62         }
  63
  64         if *overheads {
  65                 fmt.Printf(
  66                         "Plain: %d\nEncrypted: %d\nSize: %d\n",
  67                         nncp.PktOverhead,
  68                         nncp.PktEncOverhead,
  69                         nncp.PktSizeOverhead,
  70                 )
  71                 return
  72         }
  73
  74         var err error
  75         beginning := make([]byte, nncp.PktOverhead)
  76         if _, err = io.ReadFull(os.Stdin, beginning); err != nil {
  77                 log.Fatalln("Not enough data to read")
  78         }
  79         var pkt nncp.Pkt
  80         _, err = xdr.Unmarshal(bytes.NewReader(beginning), &pkt)
  81         if err == nil && pkt.Magic == nncp.MagicNNCPPv3 {
  82                 if *dump {
  83                         bufW := bufio.NewWriter(os.Stdout)
  84                         var r io.Reader
  85                         r = bufio.NewReader(os.Stdin)
  86                         if *decompress {
  87                                 decompressor, err := zstd.NewReader(r)
  88                                 if err != nil {
  89                                         log.Fatalln(err)
  90                                 }
  91                                 r = decompressor
  92                         }
  93                         if _, err = io.Copy(bufW, r); err != nil {
  94                                 log.Fatalln(err)
  95                         }
  96                         if err = bufW.Flush(); err != nil {
  97                                 log.Fatalln(err)
  98                         }
  99                         return
 100                 }
 101                 payloadType := "unknown"
 102                 switch pkt.Type {
 103                 case nncp.PktTypeFile:
 104                         payloadType = "file"
 105                 case nncp.PktTypeFreq:
 106                         payloadType = "file request"
 107                 case nncp.PktTypeExec:
 108                         payloadType = "exec"
 109                 case nncp.PktTypeExecFat:
 110                         payloadType = "exec uncompressed"
 111                 case nncp.PktTypeTrns:
 112                         payloadType = "transitional"
 113                 }
 114                 var path string
 115                 switch pkt.Type {
 116                 case nncp.PktTypeExec, nncp.PktTypeExecFat:
 117                         path = string(bytes.Replace(
 118                                 pkt.Path[:pkt.PathLen],
 119                                 []byte{0},
 120                                 []byte(" "),
 121                                 -1,
 122                         ))
 123                 case nncp.PktTypeTrns:
 124                         path = nncp.Base32Codec.EncodeToString(pkt.Path[:pkt.PathLen])
 125                 default:
 126                         path = string(pkt.Path[:pkt.PathLen])
 127                 }
 128                 fmt.Printf(
 129                         "Packet type: plain\nPayload type: %s\nNiceness: %s (%d)\nPath: %s\n",
 130                         payloadType, nncp.NicenessFmt(pkt.Nice), pkt.Nice, path,
 131                 )
 132                 return
 133         }
 134         var pktEnc nncp.PktEnc
 135         _, err = xdr.Unmarshal(bytes.NewReader(beginning), &pktEnc)
 136         if err == nil && pktEnc.Magic == nncp.MagicNNCPEv4 {
 137                 if *dump {
 138                         ctx, err := nncp.CtxFromCmdline(*cfgPath, "", "", false, false, false, false)
 139                         if err != nil {
 140                                 log.Fatalln("Error during initialization:", err)
 141                         }
 142                         if ctx.Self == nil {
 143                                 log.Fatalln("Config lacks private keys")
 144                         }
 145                         bufW := bufio.NewWriter(os.Stdout)
 146                         if _, _, err = nncp.PktEncRead(
 147                                 ctx.Self,
 148                                 ctx.Neigh,
 149                                 io.MultiReader(
 150                                         bytes.NewReader(beginning),
 151                                         bufio.NewReader(os.Stdin),
 152                                 ),
 153                                 bufW,
 154                         ); err != nil {
 155                                 log.Fatalln(err)
 156                         }
 157                         if err = bufW.Flush(); err != nil {
 158                                 log.Fatalln(err)
 159                         }
 160                         return
 161                 }
 162                 fmt.Printf(
 163                         "Packet type: encrypted\nNiceness: %s (%d)\nSender: %s\nRecipient: %s\n",
 164                         nncp.NicenessFmt(pktEnc.Nice), pktEnc.Nice, pktEnc.Sender, pktEnc.Recipient,
 165                 )
 166                 return
 167         }
 168         log.Fatalln("Unable to determine packet type")
 169 }