flow-xlate - Apply translations to selected fields of a flow.

flow-xlate [-hkn] [-b big|little] [-C comment] [-d debug_level] [-v variable binding] [-V flow_version] [-x xlate_fname] [-X xlate_definition] [-z z_level]

The flow-xlate utility is used to apply translations to flows. Translations are defined in a configuration file and are composed of actions and a definition to invoke action(s). The definitions are in the form of terms, each term can have a filter and multiple actions.

Words in the configuration file of the form @VAR or @{VAR:default} will be expanded at run-time by setting variable names with the -v option.

Translation actions begin with the xlate-action keyword followed by a symbolic name. Each action has a type defined below.

Translation definitions begin with the xlate-definition keyword followed by a symbolic name. Each definition is composed of terms which are evaluated in the order of the configuration file. A term may invoke a filter to conditionally invoke an action.

Action type/sub-commands                Description/Example
------------------------------------------------------------------------
ip-source-address-to-network            Zero host bits based on mask.
ip-destination-address-to-network       Zero host bits based on mask.

(no sub-commands)

ip-source-address-to-class-network Zero source host bits to match class. ip-destination-address-to-class-network Zero dst host bits to match class. (no sub-commands)

ip-source-address-anonymize Anonymize source address. ip-destination-address-anonymize Anonymize destination address. ip-address-anonymize Anonymize src/dst address.

algorithm Algorithm. cryptopan-aes128 is currently supported. algorithm cryptopan-aes128

key Key. Key is 128 bits in hex. key 0123456789ABCDEFG

key-file File to load key from. Key is 128 bits in hex. key-file /mfstmp/secret-key

key-file-refresh How often to check the key file. Interval is in minutes, the optional second argument is hour:min:sec to specify the first refresh. This example will load a new key every day at 12:00:00. 14400 12:00:00

ip-address-privacy-mask Apply a mask to the source and destination address to remove bits.

ip-port-privacy-mask Apply a mask to the source and destination port to remove bits.

tag-mask Apply mask to the source and destination tag.

mask Source and Destination mask to apply. mask 0xFFFF 0xFFFF

scale Scale packets and bytes.

scale Scale to apply. scale 100

replace-source-as0 Replace source AS 0 replace-destination-as0 Replace destination AS 0

as AS replacement value. as 3112

-b big|little

Byte order of output.

-C Comment

Add a comment.

-d debug_level

Enable debugging.

-h

Display help.

-k

Keep time from input.

-n

Don't load configuration file. Useful only with -V

-v variable binding

Set a variable FOO=bar.

-V pdu_version

Use pdu_version format output.

    1    NetFlow version 1 (No sequence numbers, AS, or mask)
    5    NetFlow version 5
    6    NetFlow version 6 (5+ Encapsulation size)
    7    NetFlow version 7 (Catalyst switches)
    8.1  NetFlow AS Aggregation
    8.2  NetFlow Proto Port Aggregation
    8.3  NetFlow Source Prefix Aggregation
    8.4  NetFlow Destination Prefix Aggregation
    8.5  NetFlow Prefix Aggregation
    8.6  NetFlow Destination (Catalyst switches)
    8.7  NetFlow Source Destination (Catalyst switches)
    8.8  NetFlow Full Flow (Catalyst switches)
    8.9  NetFlow ToS AS Aggregation
    8.10 NetFlow ToS Proto Port Aggregation
    8.11 NetFlow ToS Source Prefix Aggregation
    8.12 NetFlow ToS Destination Prefix Aggregation
    8.13 NetFlow ToS Prefix Aggregation
    8.14 NetFlow ToS Prefix Port Aggregation
    1005 Flow-Tools tagged version 5

-x xlate_fname

Translation config file name. Defaults to /etc/flow-tools/cfg/xlate.cfg

-X xlate_definition

Translation definition. Defaults to default.

-z z_level

Configure compression level to z_level. 0 is disabled (no compression), 9 is highest compression.

Convert the version 7 flows in flows.v7 to version 5, storing the result in flows.v5.

flow-xlate -V5 < flows.v7 > flows.v5

Set the low 11 bits in the IP addresses to zero unless the address is multicast or it belongs to the 192.88.99/24 network.

# xlate.cfg
include-filter filter.cfg

xlate-action MULTICAST-PRIVACY type ip-address-privacy-mask mask 0xFFFFFFFF 0xFFFFFFFF xlate-action UNICAST-PRIVACY type ip-address-privacy-mask mask 0xFFFFFF00 0xFFFFF800

xlate-definition abilene_privacy term filter mcast action MULTICAST-PRIVACY stop term filter ucast action UNICAST-PRIVACY

# filter.cfg
filter-primitive MCAST
  type ip-address-mask
  permit 224.0.0.0 240.0.0.0

filter-primitive UCAST type ip-address-mask deny 224.0.0.0 240.0.0.0 default permit

filter-primitive SKIP type ip-address-mask deny 192.88.99.0 255.255.255.0 default permit

filter-definition mcast match ip-destination-address MCAST

filter-definition ucast match ip-destination-address UCAST match ip-destination-address SKIP match ip-source-address SKIP flow-cat flows | flow-xlate -xxlate.cfg -Xabilene_privacy | flow-print

Configuration files: Symbols - /etc/flow-tools/sym/*. Filter - /etc/flow-tools/cfg/filter.cfg. Xlate - /etc/flow-tools/cfg/xlate.cfg.

The scale option can overflow the 32 bit flow counters. This could be solved by detecting this condition and splitting the flow in two.

Translation between aggregated and non aggregated formats is not supported.

Mark Fullmer maf@splintered.net

flow-tools(1)