-
Notifications
You must be signed in to change notification settings - Fork 0
Capturing Data
On a Mint 19 system the following command can be used to capture data from the GNSS Firehose:
sudo tcpdump -i enp2s0 -f ether host 00:01:02:03:04:09 -q -w outfile.pcap
On the current machine in use this TCPDump was not able to keep up with the data packets coming in. (i5-4590/3.3GHz)
More information on Gulp can be found at https://staff.washington.edu/corey/gulp/. There is copy of it on Github at https://github.com/joshenders/gulp.
There is a trick to compiling it. When compiled on a 64bit system it uses the 64bit PCAP library, with is incompatible with the Wireshark on Mint 19 which uses 32bit headers in the PCAP files. It is possible to build with the 32bit PCAP library but the easiest with is to change the make file to set CFLAGS = -O -DPCAP32_KLUDGE
The command used for Gulp is:
sudo gulp -i enp2s0 -f "ether host 00:01:02:03:04:09" -r 1024 > outfile.pcap
The -r 1024 enables a 1Gb buffer of which 300-700Mb has been seen to be used.
The GNSS Firehose board will output approx 100Mb/s so a file of 100s will turn into 10Gb on disk.
The desination MAC address can be changed in packet_streamer.v. Peter's original code had the broadcast MAC address of FF:FF:FF:FF:FF:FF. This was found to max out the whole home network. The MAC address has been update to send to a single computer. You will need to change this to the MAC address of the computer you are using.