I recorded a pcap file with wireshark and now I want to get rid of the pcap header.
Means: I want my .pcap file to start directly with my ethernet frame (source & destination MAC) and get rid of the PCAP headers.
libpcap files only have a 24 bytes header at the start. The following command does the trick:
cat in.pcap | tail -c +25 > out.pcap
I want to be able to capture SIP traffic and save the trace as XML file with an specific format , there is any way to do this with just wireshark - tshark commands ? FYI this will run in a Centos server .
The only way i found to create the specific format is by running a Perl script to format the XML file but is would be way better if I could do all with just wireshark?
Thanks
Tshark has options to convert a PCAP file to Text. Or you could capture it in a PDML or PSML format and then have a converter routine to your own XML format. And considering that wireshark if modifiable, you could tweak a plugin to do this differently. But i more inclined to build a converter process that parses the native pcap to what you like. So your raw data has all the information and you can freely keep changing the converter routine.
For Text Conversion -
tshark -V -r -T pdml "17c4d2c0-69cd-11e4-ae3e-9d5dee8b7eac.pcap" > capture.xml
For Capture as PDML / PSML -
tshark -T pdml
I am inclined to think that there could be options to directly covert to PSML like the Text converter from the PCAP.
The Objective
I'm trying to achieve the following:
capture network traffic containing a conversation in the FIX protocol
extract the individual FIX messages from the network traffic into a "nice" format, e.g. CSV
do some data analysis on the exported "nice" format data
I have achieved this by:
using pcap to capture the network traffic
using tshark to print the relevant data as a CSV
using Python (pandas) to analyse the data
The Problem
The problem is that some of the captured TCP packets contain more than one FIX message, which means that when I do the export to CSV using tshark I don't get a FIX message per line. This makes consuming the CSV difficult.
This is the tshark commandline I'm using to extract the relevant FIX fields as CSV is:
tshark -r dump.pcap \
-R \'(fix.MsgType[0]=="G" or fix.MsgType[0]=="D" or fix.MsgType[0]=="8" or \ fix.MsgType[0]=="F") and fix.ClOrdID != "0"\' \
-Tfields -Eseparator=, -Eoccurrence=l -e frame.time_relative \
-e fix.MsgType -e fix.SenderCompID \
-e fix.SenderSubID -e fix.Symbol -e fix.Side \
-e fix.Price -e fix.OrderQty -e fix.ClOrdID \
-e fix.OrderID -e fix.OrdStatus'
Note that I'm currently using "-Eoccurrence=l" to get just the last occurrence of a named field in the case where there is more than one occurrence of a field in the packet. This is not an acceptable solution as information will get thrown away when there are multiple FIX messages in a packet.
This is what I expect to see per line in the exported CSV file (fields from one FIX message):
16.508949000,D,XXX,XXX,YTZ2,2,97480,34,646427,,
This is what I see when there is more than one FIX message (three is this case) in a TCP packet and the commandline flag "-Eoccurrence=a" is used:
16.515886000,F,F,G,XXX,XXX,XXX,XXX,XXX,XXX,XTZ2,2,97015,22,646429,646430,646431,323180,323175,301151,
The Question
Is there a way (not necessarily using tshark) to extract each individual, protocol specific message from a pcap file?
Better Solution
Using tcpflow allows this to be done properly without leaving the commandline.
My current approach is to use something like:
tshark -nr <input_file> -Y'fix' -w- | tcpdump -r- -l -w- | tcpflow -r- -C -B
tcpflow ensures that the TCP stream is followed, so no FIX messages are missed (in the case where a single TCP packet contains more than 1 FIX message). -C writes to the console and -B ensures binary output. This approach is not unlike following a TCP stream in Wireshark.
The FIX delimiters are preserved which means that I can do some handy grepping on the output, e.g.
... | tcpflow -r- -C -B | grep -P "\x0135=8\x01"
to extract all the execution reports. Note the -P argument to grep which allows the very powerful perl regex.
A (Previous) Solution
I'm using Scapy (see also Scapy Documentation, The Very Unofficial Dummies Guide to Scapy) to read in a pcap file and extract each individual FIX message from the packets.
Below is the basis of the code I'm using:
from scapy.all import *
def ExtractFIX(pcap):
"""A generator that iterates over the packets in a scapy pcap iterable
and extracts the FIX messages.
In the case where there are multiple FIX messages in one packet, yield each
FIX message individually."""
for packet in pcap:
if packet.haslayer('Raw'):
# Only consider TCP packets which contain raw data.
load = packet.getlayer('Raw').load
# Ignore raw data that doesn't contain FIX.
if not 'FIX' in load:
continue
# Replace \x01 with '|'.
load = re.sub(r'\x01', '|', load)
# Split out each individual FIX message in the packet by putting a
# ';' between them and then using split(';').
for subMessage in re.sub(r'\|8=FIX', '|;8=FIX', load).split(';'):
# Yield each sub message. More often than not, there will only be one.
assert subMessage[-1:] == '|'
yield subMessage
else:
continue
pcap = rdpcap('dump.pcap')
for fixMessage in ExtractFIX(pcap):
print fixMessage
I would still like to be able to get other information from the "frame" layer of the network packet, in particular the relative (or reference) time. Unfortunately, this doesn't seem to be available from the Scapy packet object - it's topmost layer is the Ether layer as shown below.
In [229]: pcap[0]
Out[229]: <Ether dst=00:0f:53:08:14:81 src=24:b6:fd:cd:d5:f7 type=0x800 |<IP version=4L ihl=5L tos=0x0 len=215 id=16214 flags=DF frag=0L ttl=128 proto=tcp chksum=0xa53d src=10.129.0.25 dst=10.129.0.115 options=[] |<TCP sport=2634 dport=54611 seq=3296969378 ack=2383325407 dataofs=8L reserved=0L flags=PA window=65319 chksum=0x4b73 urgptr=0 options=[('NOP', None), ('NOP', None), ('Timestamp', (581177, 2013197542))] |<Raw load='8=FIX.4.0\x019=0139\x0135=U\x0149=XXX\x0134=110169\x015006=20\x0150=XXX\x0143=N\x0152=20121210-00:12:13\x01122=20121210-00:12:13\x015001=6\x01100=SFE\x0155=AP\x015009=F3\x015022=45810\x015023=3\x015057=2\x0110=232\x01' |>>>>
In [245]: pcap[0].summary()
Out[245]: 'Ether / IP / TCP 10.129.0.25:2634 > 10.129.0.115:54611 PA / Raw'
Recently updated my Wireshark on a server, and lost the ability to use -R and -w from the CLI. Since I'm tracing SIP and RTP calls, I need to use -R and not -f.
I found out using -V is very useful (shows the packet tree on screen) and then I can redirect the output to a file. Unfortunately I'm not able to open that file through Wireshark to view properly (contains too muh text to easily scroll through).
I tried using -x t add the hex dump (removed -V), but still that is not openable through Wireshark when copying the text file to my PC.
Any ideas how I can trace using -R (with or without -V), copy the file to my PC and still be able to read it through Wireshark? I don't have issues to convert the file to a readable format.. Just need anything to view the files and share them :)
Thanks all,
//M
I am trying to parse large pcap files with libpcap but there is a file limitation so my files are separated at 2gb. I have 10 files of 2gb and I want to parse them at one shot. Is there a possibility to feed this data on an interface sequentially (each file separately) so that libpcap can parse them on the same run?
I am not aware of any tools that will allow you to replay more than one file at a time.
However, if you have the disk space, you can use mergecap to merge the ten files into a single file and then replay that.
Mergecap supports merging the packets according to
chronological order of each packet's timestamp in each file
ignoring the timestamps and performing what amounts to a packet version of 'cat'; write the contents of the first file to the output, then the next input file, then the next.
Mergecap is part of the Wireshark distribution.
I had multiple 2GB pcap files. Used the following one liner to go through each pcap file sequentially and with display filter. This worked without merging the pcap files (avoided using more disk space and cpu)
for i in /mnt/tmp1/tmp1-pcap-ens1f1-tcpdump* ; do tcpdump -nn -r $i host 8.8.8.8 and tcp ; done
**Explanation:**
for loop
/mnt/tmp1/tmp1-pcap-ens1f1-tcpdump* # path to files with * for wildcard
do tcpdump -nn -r $i host 8.8.8.8 and tcp # tcpdump not resolving ip or port numbers and reading each file in sequence
done #
Note: Please remember to adjust the file path and display filter according to your needs.