DecIPTTL

DecIPTTL Element Documentation

NAME

DecIPTTL — Click element; decrements IP time-to-live, drops dead packets

SYNOPSIS

DecIPTTL([keyword MULTICAST])

Ports: 1 input, 1-2 outputs
Processing: agnostic, but output 1 is push

DESCRIPTION

Expects IP packet as input. If the ttl is <= 1 (i.e. has expired), DecIPTTL sends the packet to output 1 (or discards it if there is no output 1). Otherwise it decrements the ttl, re-calculates the checksum, and sends the packet to output 0.

Ordinarily output 1 is connected to an ICMP error packet generator.

• ACTIVE — Boolean. If false, do not decrement any packets' TTLs. Defaults to true.
• MULTICAST — Boolean. If false, do not decrement the TTLs for multicast packets. Defaults to true.

EXAMPLES

This is a typical IP input processing sequence:

 ... -> CheckIPHeader -> dt::DecIPTTL -> ...
 dt[1] -> ICMPError(18.26.4.24, 11, 0) -> ...

SEE ALSO

ICMPError, CheckIPHeader

Generated by click-elem2man from ../elements/ip/decipttl.hh:8 on 2017/10/17.