| .TH tcpsubnet 8 "2018-03-01" "USER COMMANDS" |
| .SH NAME |
| tcpsubnet \- Summarize and aggregate IPv4 TCP traffic by subnet. |
| .SH SYNOPSIS |
| .B tcpsubnet [\-h] [\-v] [\-J] [\-f FORMAT] [\-i INTERVAL] [subnets] |
| .SH DESCRIPTION |
| This tool summarizes and aggregates IPv4 TCP sent to the subnets |
| passed in argument and prints to stdout on a fixed interval. |
| |
| This uses dynamic tracing of kernel TCP send/receive functions, and will |
| need to be updated to match kernel changes. |
| |
| The traced data is summarized in-kernel using a BPF map to reduce overhead. |
| At very high TCP event rates, the overhead may still be measurable. |
| See the OVERHEAD section for more details. |
| |
| Since this uses BPF, only the root user can use this tool. |
| .SH REQUIREMENTS |
| CONFIG_BPF and bcc. |
| .SH OPTIONS |
| .TP |
| \-h |
| Print USAGE message. |
| .TP |
| \-v |
| Run in verbose mode. Will output subnet evaluation and the BPF program |
| .TP |
| \-J |
| Format output in JSON. |
| .TP |
| \-i |
| Interval between updates, seconds (default 1). |
| .TP |
| \-f |
| Format output units. Supported values are bkmBKM. When using |
| kmKM the output will be rounded to floor. |
| .TP |
| subnets |
| Comma separated list of subnets. Traffic will be categorized |
| in theses subnets. Order matters. |
| (default 127.0.0.1/32,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16,0.0.0.0/0) |
| .SH EXAMPLES |
| .TP |
| Summarize TCP traffic by the default subnets: |
| # |
| .B tcpsubnet |
| .TP |
| Summarize all TCP traffic: |
| # |
| .B tcpsubnet 0.0.0.0/0 |
| .TP |
| Summarize all TCP traffic and output in JSON and Kb: |
| # |
| .B tcpsubnet -J -fk 0.0.0.0/0 |
| .SH FIELDS |
| .TP |
| (Standad output) Left hand side column: |
| Subnet |
| .TP |
| (Standard output) Right hand side column: |
| Aggregate traffic in units passed as argument |
| .TP |
| (JSON output) date |
| Current date formatted in the system locale |
| .TP |
| (JSON output) time |
| Current time formatted in the system locale |
| .TP |
| (JSON output) entries |
| Map of subnets to aggregates. Values will be in format passed to -f |
| .SH OVERHEAD |
| This traces all tcp_sendmsg function calls in the TCP/IP stack. |
| It summarizes data in-kernel to reduce overhead. |
| A simple iperf test (v2.0.5) with the default values shows a loss |
| of ~5% throughput. On 10 runs without tcpsubnet running the average |
| throughput was 32.42Gb/s, with tcpsubnet enabled it was 31.26Gb/s. |
| This is not meant to be used as a long running service. Use it |
| for troubleshooting or for a controlled interval. As always, |
| try it out in a test environment first. |
| |
| .SH SOURCE |
| This is from bcc. |
| .IP |
| https://github.com/iovisor/bcc |
| .PP |
| Also look in the bcc distribution for a companion _examples.txt file containing |
| example usage, output, and commentary for this tool. |
| .SH OS |
| Linux |
| .SH STABILITY |
| Unstable - in development. |
| .SH AUTHOR |
| Rodrigo Manyari |
| .SH INSPIRATION |
| tcptop(8) by Brendan Gregg |
| .SH SEE ALSO |
| netlink(7) |
