Interesting packet from FMC880 (firmware bug in FMC880?) #4
Comments
|
The test code looks like this: package server
import (
"encoding/binary"
"encoding/hex"
"fmt"
"testing"
"time"
"github.com/alim-zanibekov/teltonika"
"github.com/davecgh/go-spew/spew"
"github.com/lab5e/tracker/pkg/bufreader"
"github.com/stretchr/testify/require"
)
const (
data = "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"
)
func TestBuggyPacket(t *testing.T) {
packet, err := hex.DecodeString(data)
require.NoError(t, err)
b := bufreader.New(packet, binary.BigEndian)
preamble, err := b.Uint32()
require.NoError(t, err)
fmt.Printf("preamble = %d\n", preamble)
length, err := b.Uint32()
require.NoError(t, err)
fmt.Printf("length = %d\n", length)
codec, err := b.Uint8()
require.NoError(t, err)
fmt.Printf("codec = 0x%02x\n", codec)
numdata1, err := b.Uint8()
require.NoError(t, err)
fmt.Printf("numdata = %d\n", numdata1)
for i := 0; i < 4; i++ {
println("element ", i)
timestamp, err := b.Int64()
require.NoError(t, err)
fmt.Printf(" timestamp = %d (%s)\n", timestamp, time.UnixMilli(timestamp).Format(time.RFC3339))
priority, err := b.Uint8()
require.NoError(t, err)
fmt.Printf(" priority = %d\n", priority)
lon, err := b.Int32()
require.NoError(t, err)
fmt.Printf(" lon = %d\n", lon)
lat, err := b.Int32()
require.NoError(t, err)
fmt.Printf(" lat = %d\n", lat)
alt, err := b.Int16()
require.NoError(t, err)
fmt.Printf(" alt = %d\n", alt)
angle, err := b.Int16()
require.NoError(t, err)
fmt.Printf(" angle = %d\n", angle)
sat, err := b.Uint8()
require.NoError(t, err)
fmt.Printf(" sat = %d\n", sat)
speed, err := b.Int16()
require.NoError(t, err)
fmt.Printf(" speed = %d\n", speed)
eventID, err := b.Uint16()
require.NoError(t, err)
fmt.Printf(" eventID = %d\n", eventID)
ioCount, err := b.Uint16()
require.NoError(t, err)
k := 0
for i := 1; i <= 8; i *= 2 {
n, err := b.Uint16()
require.NoError(t, err)
for j := 0; j < int(n); j++ {
id, err := b.Uint16()
require.NoError(t, err)
value, err := b.ReadBytes(i)
require.NoError(t, err)
if k >= int(ioCount) {
require.Fail(t, fmt.Errorf("too many i/o elements, expected at most %d, found %d", ioCount, k).Error())
}
fmt.Printf(" - ioelement id=%d = data=%s\n", id, hex.EncodeToString(value))
k++
}
}
ioCountNX, err := b.Uint16()
require.NoError(t, err)
fmt.Printf(" ioCountNX = %d\n", ioCountNX)
fmt.Printf(" k = %d\n", k)
for i := k; i < int(ioCountNX); i++ {
id, err := b.Uint16()
require.NoError(t, err)
length, err := b.Uint16()
require.NoError(t, err)
value, err := b.ReadBytes(int(length))
require.NoError(t, err)
if i >= int(ioCount) {
require.Fail(t, fmt.Errorf("too many i/o elements, expected at most %d, found %d", ioCount, i).Error())
}
fmt.Printf(" - ionx id=%d = data=%s\n", id, hex.EncodeToString(value))
}
}
numdata2, err := b.Uint8()
require.NoError(t, err)
fmt.Printf("numdata = %d\n", numdata2)
checksum, err := b.Uint32()
require.NoError(t, err)
fmt.Printf("checksum = %d\n", checksum)
remain := b.Remaining()
rest, err := b.ReadBytes(remain)
require.NoError(t, err)
fmt.Printf("REMAIN: %d\n", remain)
fmt.Printf("rest = %s\n", hex.EncodeToString(rest))
fmt.Println("--------------------------------------------------------------------")
// require.NoError(t, err)
n, pkt, err := teltonika.DecodeTCPFromSlice(packet)
fmt.Printf("err=%v\n", err)
fmt.Printf("n = %d\n", n)
fmt.Printf("pkt = %+v\n", pkt)
spew.Dump(packet)
}and the output it generated looks like this: |
|
Hi @borud, thank you for the feedback! It seems we both made a mistake in the code :) "Number of Data 1" and "Number of Data 2" in your packet I made a mistake in the 8E codec I/O elements decoding logic, specifically in the variable length I/O element read loop, I fixed the problem and now everything is working fine package main
import (
"encoding/hex"
"fmt"
"github.com/alim-zanibekov/teltonika"
"github.com/alim-zanibekov/teltonika/ioelements"
)
func main() {
packetHex := "00000000000003c68e04000001909d6417c801062c583a25ce28b9004f004530000000ef0011000500ef0000f0010015030" +
"0c800004501000a00b5000800b60004004234a90018000000430ef700440052001100900012fc4c0013fb77000f03e8000200f100005" +
"e89001000003f9a00000000000001909d606e5201062bc70c25ccd6d50096010032000000ef0011000500ef0100f00100150500c8000" +
"04501000a00b5000800b60005004237780018000000430ed500440000001100da0012fd0e0013f9ef000f03e8000200f100005e89001" +
"000003a6400000000000001909d4f2c5001062bc70c25ccd6d5009601002c000000ef0011000500ef0000f00100150500c8000045010" +
"00a00b5000800b60005004234b10018000000430f0300440041001100db0012fd0d0013f9e9000f0047000200f100005e89001000003" +
"a6400000000000001909d4e03d501062c0f5025cdd1170068008130004800f700030002013d0100f7050000000000000001010102580" +
"1dffe02f95d01c2fdc4f97001b1fde2f96f0193fdd2f97001a1fe01f95f0171fdfff95001b1fdf3f97e01a1fe01f95f0200fdd5f97d0" +
"1eefe12f95c01affe31f96d01d0fe33f9aa01cffe62f9a901b1fe43f9ba01a0fe51f99b0200fe05f99b01d0fe33f99b0170fe6ff99b0" +
"161fe6ff9ab0164fe22f9cd0192fe22f99d0183fe32f9cc0170fe6ff99b0142fe4ff99d0133fe6ef9bc0172fe30f99d01c2fe15f9cb0" +
"19ffe70f99a0182fe11f97e0183fdf2f99f0152fe2ff98e0163fe21f9ae0181fe2ff96e0152fe2ff98e0162fe30f98e0191fe11f97e0" +
"1c0fe12f97d019ffe20f94e0180fe2ff95e0192fde1f96001a1fdf1f95f01d1fdc4f96f01a2fdc2f95101bffdf0f9300182fde1f9610" +
"1d1fdb3f94101a1fdd0f93201c2fda3f95101b1fdd1f94101b1fdd1f94101effde3f94e01b0fdf1f94001c0fde1f94001c1fdd2f9500" +
"171fdeef92201b0fde1f94001a1fdc1f93201a0fdc0f9130171fdcff92301dffdb2f9120190fdfff9300191fde0f9410191fe00f95f0" +
"172fdd0f94201cffde1f92001bdfdeef8e201affdd0f91201c0fdc2f93101a1fdb1f93301bffde0f92101f1fd74f92301a1fd80f8f60" +
"1d1fd83f91401a0fdaff8f401a0fde0f92101affdc0f90301bffdd0f90201dffdb1f90201cefdbff8e301eefda2f8f3019ffdaef8c50" +
"1f0fd94f932019ffddff90201b0fe01f94f01ddfdfff90001bbfe4cf8ee01befe30f94d01cdfe1ff90f01cffdf2f94f019ffe1ff93f0" +
"1b1fdd2f9600191fe00f95f0184fdc3f9910192fe12f99d01a0fe10f95e0180fe4ff97c01a1fe31f98c01a0fe21f96e0193fdf2f98f0" +
"191fe21f98d0400006a96"
packet, _ := hex.DecodeString(packetHex)
_, decoded, err := teltonika.DecodeTCPFromSlice(packet)
if err != nil {
panic(err)
}
decoder := ioelements.DefaultDecoder()
elements := make([][]*ioelements.IOElement, len(decoded.Packet.Data))
for i, data := range decoded.Packet.Data {
elements[i] = make([]*ioelements.IOElement, len(data.Elements))
for j, element := range data.Elements {
elements[i][j], err = decoder.Decode("*", element.Id, element.Value)
if err != nil {
panic(err)
}
}
}
for i, items := range elements {
fmt.Printf("\nFrame #%d\n", i)
d := decoded.Packet.Data[i]
fmt.Printf(" timestamp: %v\n", d.TimestampMs)
fmt.Printf(" priority: %v\n", d.Priority)
fmt.Printf(" lng: %v\n", d.Lng)
fmt.Printf(" lat: %v\n", d.Lat)
fmt.Printf(" alt: %v\n", d.Altitude)
fmt.Printf(" angle: %v\n", d.Angle)
fmt.Printf(" speed: %v\n", d.Speed)
fmt.Printf(" satellites: %v\n", d.Satellites)
fmt.Printf(" I/O elements\n")
for _, element := range items {
fmt.Printf(" %s\n", element)
}
}
}Output |
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hi,
Thanks for a great library. I started using it and things seem to work pretty well. Today I came across a packet from an FMC880 that the device keeps trying to send to the server over and over again.
The packet is sent over TCP and this is the hex encoding of it (this is just a dump of the entire buffer, so the stuff at the end is just zeroes from the zeroed buffer):
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 wrote my own parser for the packet and IO elements and it seems to confirm that your code is correct. The packet looks corrupt since NumberOfData1 equals 4 and NumberOfData2 equals 1. And your
teltonika.DecodeTCPFromSlicefunction returns the error'Number of Data 1' is not equal to 'Number of Data 2'. 4 != 1".I thought I'd give you a copy of the packet in case you see something that is off here. But I think both your code and mine parses it correctly and correctly concludes it is buggy. Right?
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