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diff --git a/man/netsniff-ng.8 b/man/netsniff-ng.8 new file mode 100644 index 0000000..48e28b0 --- /dev/null +++ b/man/netsniff-ng.8 @@ -0,0 +1,157 @@ +.\" netsniff-ng - the packet sniffing beast +.\" Copyright 2013 Daniel Borkmann. +.\" Subject to the GPL, version 2. + +.TH NETSNIFF-NG 8 "03 March 2013" "Linux" "netsniff-ng toolkit" +.SH NAME +netsniff-ng \- the packet sniffing beast + +.SH SYNOPSIS + +\fB netsniff-ng\fR { [\fIoptions\fR] [\fIfilter-expression\fR] } + +.SH DESCRIPTION + +Blubber. + +.SH OPTIONS + +.SS -d <netdev>, --dev <netdev> +Networking device to fetch statistics from, e.g. eth0, wlan0. + +.SS -v, --version +Show versioning information. + +.SS -h, --help +Show user help. + +.SH USAGE EXAMPLE + +.SS netsniff-ng --in eth0 --out dump.pcap -s -T 0xa1e2cb12 -b 0 tcp or udp +Capture TCP or UDP traffic from the networking device eth0 into the pcap file +named dump.pcap, which has netsniff-ng specific pcap extensions (see +``netsniff-ng -D'' for capabilities). Also, do not print the content to the +terminal and pin the process and NIC IRQ affinity to CPU 0. The pcap write +method is scatter-gather I/O. + +.SS netsniff-ng --in wlan0 --rfraw --out dump.pcap --silent --bind-cpu 0 +Put the wlan0 device into monitoring mode and capture all raw 802.11 frames +into the file dump.pcap. Do not dissect and print the content to the terminal +and pin the process and NIC IRQ affinity to CPU 0. The pcap write method is +scatter-gather I/O. + +.SS netsniff-ng --in dump.pcap --mmap --out eth0 -k1000 --silent --bind-cpu 0 +Replay the pcap file dump.pcap which is read through mmap(2) I/O and send +the packets out via the eth0 networking device. Do not dissect and print the +content to the terminal and pin the process and NIC IRQ affinity to CPU 0. +Also trigger the kernel every 1000us to traverse the TX_RING instead of every +10us. Note that the pcap magic type is detected automatically from the pcap +file header. + +.SS netsniff-ng --in dump.pcap --out dump.cfg --silent +Convert the pcap file dump.pcap into a trafgen(8) configuration file dump.cfg. +Do not print pcap contents to the terminal. + +.SS netsniff-ng --in eth0 --out eth1 --silent --bind-cpu 0 --type host -r +Redirect network traffic from the networking device eth0 to eth1 for traffic +that is destined to our host, thus ignore broadcast, multicast and promiscuous +traffic. Randomize the order of packets for the outgoing device and do not +print any packet contents to the terminal. Also, pin the process and NIC IRQ +affinity to CPU 0. + +.SS netsniff-ng --in team0 --out /opt/probe/ -s -m -J --interval 100MiB -b 0 +Capture on an aggregated team0 networkoing device and dump packets into multiple +pcap files that are split into 100MiB each. Use mmap(2) I/O as a pcap write +method, enable support for super jumbo frames up to 64KB, and do not print +the captured data to the terminal. Pin netsniff-ng to and NIC IRQ affinity to +CPU 0. The default pcap magic type is 0xa1b2c3d4 (tcpdump-capable pcap). + +.SS netsniff-ng --in vlan0 --out dump.pcap -c -u `id -u bob` -g `id -g bob` +Capture network traffic on device wlan0 into a pcap file called dump.pcap +by using normal read(2), write(2) I/O for the pcap file (slower but less +latency). Also, after setting up the RX_RING for capture, drop priviledges +from root to the user/group ``bob''. Invoke the packet dissector and print +packet contents to the terminal for further analysis. + +.SS netsniff-ng --in any --filter http.bpf --jumbo-support --ascii -V +Capture from all available networking interfaces and install a low-level +filter that was previously compiled by bpfc(8) into http.bpf in order to +filter HTTP traffic. Enable super jumbo frame support and only print +human readable packet data to the terminal, be also more verbose during +setup phase. + +.SS bla + +.SH NOTE +For introducing bit errors, delays with random variation and more +while replaying pcaps, make use of tc(8) with its disciplines such +as netem. + +netsniff-ng does only some basic, architecture generic tuning on +startup. If you are considering to do high performance capturing, +you need to carefully tune your machine, hardware and software-wise. +Simply letting netsniff-ng run without thinking about your underlying +system might not necessarily give you the desired performance. Note +that tuning your system is always a tradeoff and fine-grained +balancing act (e.g. throughput vs. latency). You should know what +you're doing! + +One recommendation for software-based tuning is tuned(8). Besides +that, there are many other things to consider. Just to throw you +a few things that you might want to look at: NAPI networking drivers, +tickless kernel, I/OAT DMA engine, Direct Cache Access, RAM-based +file systems, multi-queues, and many more things. Also, you might +want to read the kernel's Documentation/networking/scaling.txt file +regarding technologies such as RSS, RPS, RFS, aRFS and XPS. Also +check your ethtool(8) settings, e.g. regarding offloading. + +Moreover, to get a deeper understanding of netsniff-ng internals +and how it interacts with the Linux kernel, the kernel documentation +under Documentation/networking/{packet_mmap.txt, filter.txt, +multiqueue.txt} might be of interest. + +If you do not need to dump all possible traffic, you have to consider +running netsniff-ng with a BPF filter for the ingress path. For that +purpose, read the bpfc(8) man page. + +Also, to aggregate multiple NICs that you want to capture on, you +should consider using team devices, further explained in libteam resp. +teamd(8). + +The following netsniff-ng pcap magic numbers are compatible with other +tools, at least tcpdump or Wireshark: + + 0xa1b2c3d4 (tcpdump-capable pcap) + 0xa1b23c4d (tcpdump-capable pcap with ns resolution) + 0xa1b2cd34 (Alexey Kuznetzov's pcap) + +.SH BUGS + +When replaying pcap files, the timing information from the pcap packet +header is currently ignored. + +Also, when replaying pcap files, demultiplexing traffic among multiple +networking interfaces does not work. Currently, it is only sent via the +interface that is given by the --out parameter. + +.SH LEGAL +netsniff-ng is licensed under the GNU GPL version 2.0. + +.SH HISTORY +.B netsniff-ng +was originally written for the netsniff-ng toolkit by Daniel Borkmann. Bigger +contributions were made by Emmanuel Roullit, Markus Amend, Tobias Klauser and +Christoph Jaeger. It is currently maintained by Tobias Klauser +<tklauser@distanz.ch> and Daniel Borkmann <dborkma@tik.ee.ethz.ch>. + +.SH SEE ALSO +.BR trafgen (8), +.BR mausezahn (8), +.BR ifpps (8), +.BR bpfc (8), +.BR flowtop (8), +.BR astraceroute (8), +.BR curvetun (8) + +.SH AUTHOR +Manpage was written by Daniel Borkmann. |