I have a hex dump generated using gdb. I have generated the dump that wireshark can understand using "od -Ax -tx1 -v". But when I open in the wireshark tool the packet doesn't get recognized properly. I think wireshark is trying to read the ethernet frame while the buffer has data from IP header. Is there a way to indicate wireshark to parse hexdump assuming fro IP header.
Have a look at text2pcap. There are 2 basic approaches you can take:
Add a dummy Ethernet header using the -e <l3pid> option, or
Set the encapsulation type of the converted pcap file to link-layer type LINKTYPE_RAW using the -l 101 option.
Related
I have a requirement to expand required tree in decoded parameters of pcap file and validate a message in it.
Example:
Open "Transmission Control Protocol" as shown in screenshot and and validate for the message "This is an ACK to the segment in frame: 278".
Need to develop an automation script in Java for validating messages in pcap files . Currently am using jnetpcap lib.
Appreciate your inputs!.
You can't, without protocol analysis by yourself. A pcap file doesn't include such massages.
The message "This is an ACK to the segment in frame: 278" was generated by wireshark after TCP session analysis by itself. Even the frame number 278 was assigned by wireshark. A pcap file only contains packets' data.
Here I need parse a custom protocol in many .pcapng files , I want direct filter and output the application raw data via tshark command .
At first , I use the "-e data.data" option , but ,some of the application data could be decode as other protocol , and wouldn't be output by -e data.data.
Then , I find a way that special the "disable-protocol" file under wireshark profile folder,but ,I must take the profile file and deploy it before run the parse program on other PC.
And, I tried disable all the protocol except udp and tcp ,but it can't work.
I also disable the known conflict protocols , it works ,but there may be same mistake on other unknown protocol and the tshark's output still can't be trust completely.
I works on Windows7 and wireshark 2.2.use python 2.7 for parse work.
In a summary , what I want is a portable command line that can flexible and direct output all data after UDP information in a net frame.
could I disable decode on some ports by just add options in command line?
EDIT1:
I find in wireshark 1.12,there is a "Do not decode" option in "decode as..." dialog , if enable it,the display is what I want.but in wireshark 2.2,they removed the option.and I still need a command line to do this filter.
After 48 hours and 26 times viewed ,it still no response but one vote up.
I already give up this way, and decode the frame by myself.
what I want is the udp srcport and dstport, and the application data.
In actual , every net frame has a same length of header , so ,it's easy to strip the header by a fixed offset , and get the special data.
In my case , I just do some filter and use -x option for output.,as this:
tshark -r xxx.pcapng -j udp -x
the output may looks like this:
(just for example,not real case)
Every line contains three parts :The first column is offset reference, the next 16 columns are bytes in hex , and the remains are the characters map to the data.
My code:
def load_tshark_data(tshark_file_path):
tshark_exe = "c:/Program Files/Wireshark/tshark.exe"
output = subprocess.check_output([
tshark_exe,
"-r",tshark_file_path,
"-j","udp",
"-x"
])
hex_buff = ""
line_buff = ""
for c in output:
if c == "\n":
if len(line_buff) > 54:
hex_buff += line_buff[5:53]
line_buff = ''
else:
src_port = int(hex_buff[0x22*3 : 0x24*3].replace(" ",""),16)
dst_port = int(hex_buff[0x24*3 : 0x26*3].replace(" ",""),16)
app_data = hex_buff[0x2a*3 : ].strip(" ")
hex_buff = ""
yield [src_port, dst_port, app_data]
else:
line_buff += c
hope this can help any one also blocked by such a problem
I'm trying to send and receive packets with scapy and read the RadioTap Header. The wireless adapter (and driver) is able to handle those headers, but I can't seem to get them.
Whenever I send a normal packet in scapy, is does not contain such a header (thus, sniffing packets and checking one with pkt.haslayer(RadioTap) returns 0, and I am not able to display the header like with pkt[RadioTap].show() ).
If I explicitly construct my packets with a RadioTap header (like in a
pkt = RadioTap() and view it, I can get a RadioTap header, but it is empty. After sending it and receiving it, I can get still nothing.
I read posts like this one. But I don't have the problem that the RadioTap header doesn't get decoded, it's simply not filled with anything.
I'm using scapy 2.3.1, if this makes any difference. Any ideas?
Please make sure that your wireless interface and the driver support monitor mode.
$ iw list
...
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* monitor <-- here
* P2P-client
* P2P-GO
* P2P-device
And your interface is configured to monitor mode with a specific channel (e.g. ch=6).
$ sudo ip link set wlan0 down
$ sudo iw dev wlan0 set type monitor
$ sudo ip link set wlan0 up
$ sudo iw dev wlan0 set channel 6
It is also good idea to try with tools like wireshark first to see if RadioTap is visible.
I am trying to use TCP Sampler for creating an automatic tests on top of IMAP4.
I am not using the Mail Reader Sampler because i need to allow injecting pure IMAP4 commands.
My IMAP4 server (like any IMAP4 server) expect to receive any IMAP4 command end with CRLF (0D0A) so there fore i have ended my command in the Text to send area with a new line (Enter).
I sniffed the traffic and noticed that the JMeter added only LF (0A) after the command (without the Carriage return)
Is there something that i am missing here ?
How can i enforce JMeter TCP Sampler to add CRLF at the end of every TCP command ?
Using XML-escaped solved the problem !!!
http://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references
In the JMX file that is based on XML I appended the 0xD Character explicitly:
1 login 972557557566#is433.email.com a123456A
While I could not get the EOL fix to work, nor the XML approach, I did find the following post which provides another solution: http://community.blazemeter.com/knowledgebase/articles/268778-how-to-send-control-characters-using-the-jmeter-tc. The general idea is to do the following:
Create user defined variables called 'new_line' and 'carriage_return'.
Set those user defined variables to %0A and %0D, respectively.
Before your tcp sampler, create a BeanShell PreProcessor.
In the BeanShell PreProcessor, overwrite the variable values like so:
vars.put("new_line_char",URLDecoder.decode(vars.get("new_line_char"), "ASCII"));
vars.put("carriage_return_char",URLDecoder.decode(vars.get("carriage_return_char"), "ASCII"));
In your TCP Sampler, include your new variables at the end of your line
some data to send to some place${carriage_return_char}${new_line_char}
I have a Zebra GK420d connect to OS X via CUPS. However, when I send files to it that are written in ZPL or EPL they are only printed in plain text.
Am I required to change to mode on the printer?
Contrary to what others said, you don't need to specially add a raw queue.
Instead, you can submit raw files into any queue using -o raw switch:
lpr -P CupsPrinterName -o raw path/to/label.zpl
Printer name can be found over that link in CUPS:
http://localhost:631/printers/
This also works on other platforms that use CUPS, like Linux.
You can create a raw CUPS queue with lpadmin. Here's the command line I used:
lpadmin -p Zebra -E -v usb://Zebra%20Technologies/ZTC%20LP%202824%20Plus?serial=XXXXXX -m raw
You can also set up a raw queue using the CUPS web admin at
http://127.0.0.1:631/
This is a bit more comprehensive answer since I seem to be returning to this question every couple of years. To print with a Zebra or other barcode printers in Linux from command line follow these steps:
List all printer targets and find the printer you want to use:
$ lpinfo -v
network https
serial serial:/dev/ttyS0?baud=115200
serial serial:/dev/ttyS1?baud=115200
network lpd
direct hp
direct usb://GODEX/G500?serial=162203C6
network smb
...
Add new queue:
$ lpadmin -p godex -E -v usb://GODEX/G500?serial=162203C6 -m raw -o usb-unidir-default=true
If your printing is slow (takes long to start), please make sure you added -o usb-unidir-default=true.
Check available queues:
$ lpstat -v
device for godex: usb://GODEX/G500?serial=162203C6
Create a label (text file):
Create a file according to your printer's requirements in EPL (Zebra), ZPL (Zebra), EZPL (Godex).
Warning, certain CUPS versions might have an issue with raw files if they are under 512 bytes of length - longer files will print, while shorter will print once and then stall for a couple of minutes (looks like there is a timeout built in). A workaround is to add comments to extend it over 512 byte limit.
Example Zebra file (test.epl):
N
A20,20,0,2,1,1,N,"text"
B20,40,0,1,1,1,30,N,"aaaa-bbbb-cccc"
P1
Example Godex file (test.ezpl):
;set portrait orientation
^XSET,ROTATION,0
;set height 20mm
^Q20,1
;set width 64mm
^W64
;start label
^L
;AA=print out text with smallest font, x=20dots, y=20dots, magnificationx=0, magnificationy=0, gap=1dot, rotationInverse=0 (no)
AA,20,20,0,0,1,0,Some sample text
;BQ=code128, x=20dots,y=40dots,narrow_bar_width=1,wide_bar_width:2,height=30dots,rotation=0deg,readable=0(no)
BQ,20,40,1,2,30,0,0,1234-1243-43214-432141
;end label
E
Push to printer:
$ lpr -P godex test.ezpl
You would need to avoid any filtering. Print using a RAW filter, as configured in the CUPS interface, or by default in your lpadmin statement. You did not state how the printer was connected, but if IP, your destination would most-likely be socket://ip.addr.ess:9100.
I am a PC guy so I don't know CUPS well, but I have used zpl and epl on PC's and found that they really like to get the raw print files. I always do a :
filecopy "c:\zplfile.txt" "\computername\printershare" type command.
I have used wordpad too, if I just want to do some text. But for labels and barcodes I would see if there is a way for you to send the raw zpl or epl to the printer port. Hope this helps.
Thanks. I have looked at it some more. It seems that while using cups you cannot send raw ZPL commands to the printer. Like what I did was create the printer in cups as a socket and started a netcat listener on 9100 and then issued some sort of command to the printer
nc -l localhost 9100
zpl_mine="^XA ~SD10 ^PW 850 ^MM T ^MN W ^JUS ^XZ,";echo $zpl_mine | nc localhost 9100 -w 1
and this does not send the information to the printer, but I have seen on some forums that you have to use some form of language like C to parse the information