---
name: "tc-simple"
section: "8"
platform: "linux"
package: "iproute2"
version: "7.3.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/tc-simple"
---

# tc-simple(8)

basic example action

## NAME

simple - basic example action

## SYNOPSIS

**tc** ... **action simple** \[ **sdata** *STRING* \] \[ **index** *INDEX* \] \[ *CONTROL* \]

*CONTROL* := { **reclassify** \| **pipe** \| **drop** \| **continue** \| **ok** }

## DESCRIPTION

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.

## OPTIONS

- **sdata** *STRING*

  The actual string to print.

- **index** *INDEX*

  Optional action index value.

- *CONTROL*

  Indicate how **tc** should proceed after executing the action. For a description of the possible *CONTROL* values, see [**tc-actions**(8)](/tc-actions/8.md).

## EXAMPLES

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

  ```
    $ tc qdisc add dev eth0 ingress
    $ tc filter add dev eth0 parent ffff: protocol ip prio 5 \
  	 u32 match ip protocol 1 0xff flowid 1:1 action simple sdata "Incoming ICMP"
    $ 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
    $ 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
    $ dmesg | grep simple
    [135354.473951] simple: Incoming ICMP_1
    $ 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
  ```

## SEE ALSO

[**tc**(8)](/tc/8.md) [**tc-actions**(8)](/tc-actions/8.md)