Network Layer Decodes

Class ICMP

Provides access to fields in an (IPv4) ICMP header.

Instance Variables
type icmp.type -> anInteger

ICMP message type
code icmp.code -> anInteger

ICMP message code
checksum icmp.checksum -> anInteger

ICMP checksum -> aByteArray

All the ICMP bytes, i.e. header and payload.  Use this if you need to work with some of the ICMP message types that python-libtrace doesn't decode fully
payloadicmp.payload ->anIP for types 3, 4, 5, 11 and 12, otherwise aByteArray

Most ICMP messages carry some content from the packet that triggered them;  icmp.payload returns as much as it can of the triggering packet

The content of an  (IPv4) ICMP header varies depending on its type field.  python-libtrace decodes the following types ...

Echo Request (type 8) and Echo Reply (type 0)
ident icmp.echo.ident -> anInteger

Echo identifier
sequence  icmp.echo.sequence -> anInteger

Echo sequence number

Redirect (type 5)
gateway icmp.redirect.gateway -> anIPprefix

Returns IPv4 address of the gateway

Nevil Brownlee
Sat, 22 Oct 16 (NZDT)