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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | COLOPHON |
Simple action in tc(8) Linux Simple action in tc(8)
simple - basic example action
tc ... action simple STRING
This is a pedagogical example rather than an actually useful action.
Upon every access, it prints the given STRING which may be of
arbitrary length.
STRING The actual string to print.
The following example makes the kernel yell "Incoming ICMP!" every
time it sees an incoming ICMP on eth0. Steps are:
1) Add an ingress qdisc point to eth0
2) Start a chain on ingress of eth0 that first matches ICMP then
invokes the simple action to shout.
3) display stats and show that no packet has been seen by the action
4) Send one ping packet to google (expect to receive a response
back)
5) grep the logs to see the logged message
6) display stats again and observe increment by 1
hadi@noma1:$ tc qdisc add dev eth0 ingress
hadi@noma1:$tc filter add dev eth0 parent ffff: protocol ip prio 5 \
u32 match ip protocol 1 0xff flowid 1:1 action simple "Incoming ICMP"
hadi@noma1:$ sudo tc -s filter ls dev eth0 parent ffff:
filter protocol ip pref 5 u32
filter protocol ip pref 5 u32 fh 800: ht divisor 1
filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
match 00010000/00ff0000 at 8
action order 1: Simple <Incoming ICMP>
index 4 ref 1 bind 1 installed 29 sec used 29 sec
Action statistics:
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
hadi@noma1$ ping -c 1 www.google.ca
PING www.google.ca (74.125.225.120) 56(84) bytes of data.
64 bytes from ord08s08-in-f24.1e100.net (74.125.225.120): icmp_req=1 ttl=53 time=31.3 ms
--- www.google.ca ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 31.316/31.316/31.316/0.000 ms
hadi@noma1$ dmesg | grep simple
[135354.473951] simple: Incoming ICMP_1
hadi@noma1$ sudo tc/tc -s filter ls dev eth0 parent ffff:
filter protocol ip pref 5 u32
filter protocol ip pref 5 u32 fh 800: ht divisor 1
filter protocol ip pref 5 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
match 00010000/00ff0000 at 8
action order 1: Simple <Incoming ICMP>
index 4 ref 1 bind 1 installed 206 sec used 67 sec
Action statistics:
Sent 84 bytes 1 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
tc(8)
This page is part of the iproute2 (utilities for controlling TCP/IP
networking and traffic) project. Information about the project can
be found at
⟨http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2⟩.
If you have a bug report for this manual page, send it to
netdev@vger.kernel.org, shemminger@osdl.org. This page was obtained
from the project's upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git⟩
on 2017-07-05. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-to-
date source for the page, or you have corrections or improvements to
the information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
iproute2 12 Jan 2015 Simple action in tc(8)