8.3.1.11. Filter

This module contains the L23 port filter classes that deal with configuration of the filters on the received traffic of a port.

The filter command names all have the form PF_<xxx>, and require both a module index id and a port index id, as well as a sub-index identifying a particular filter.

Each filter specifies a compound Boolean condition on these true/false values to determine if the filter as a whole is true/false.

While a filter is enabled, neither its condition nor the definition of each match term or length term used by the condition can be changed.

class PF_COMMENT[source]

Bases: object

The description of a filter.

class GetDataAttr[source]

Bases: ResponseBodyStruct

comment: string, the description of the filter.

class SetDataAttr[source]

Bases: RequestBodyStruct

comment: string, the description of the filter.

get()[source]

Get the description of a filter.

Returns:: the description of the filter
Return type:: PF_COMMENT.GetDataAttr

set(comment)[source]

Set the description of a filter.

Parameters:: comment (str) – the description of the filter.

class PF_CONDITION[source]

Bases: object

The boolean condition on the terms specifying when the filter is satisfied. The condition uses a canonical and-or-not expression on the match terms and length terms. The condition is specified using a number of compound terms, each encoded as an integer value specifying an arbitrary set of the match terms and length terms defined for the port. Each match or length term has a specific power-of-two value, and the set is encoded as the sum of the values for the contained terms:

Value for match term [match_term_xindex] = 2^match_term_xindex

Value for length term [length_term_xindex] = 2^(length_term_xindex+16)

A compound term is true if all the match terms and length terms contained in it are true. This supports the and-part of the condition. If some compound term is satisfied, the condition as a whole is true.

This is the or-part of the condition. The first few compound terms at the even positions (second, fourth, …) are inverted, and all the contained match terms and length terms must be false at the same time that the those of the preceding compound term are true. This is the not-part of the condition.

At the top level, a condition is a bunch of things or-ed together.

<filter-condition> = <or-expr>

Two of the or-operands are general, two are ‘simple’.

<or-expr> = <general-and-expr> or <general-and-expr> or <simple-and-expr> or <simple-and-expr>

A ‘general’ and-expression can include negated terms.

<general-and-expr> = <term> and <term> and ... and not <term> and ... and not <term>

A ‘simple’ and-expression can only have non-negated terms.

<simple-and-expr> = <term> and <term> and ... and <term>

<term> = <match-term>

<term> = <length-term>

In practice, the simplest way to generate these encodings is to use the ValkyrieManager, which supports Boolean expressions using the operators &, |, and ~, and simply query the chassis for the resulting script-level definition.

class GetDataAttr[source]

Bases: ResponseBodyStruct

and_expression_0: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_1: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_2: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_3: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_not_expression_0: unsigned integer, encoding a compound term which is a set of the match NOT terms AND length NOT terms.

and_not_expression_1: unsigned integer, encoding a compound term which is a set of the match NOT terms AND length NOT terms.

class SetDataAttr[source]

Bases: RequestBodyStruct

and_expression_0: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_1: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_2: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_expression_3: unsigned integer, encoding a compound term which is a set of the match terms AND length terms.

and_not_expression_0: unsigned integer, encoding a compound term which is a set of the match NOT terms AND length NOT terms.

and_not_expression_1: unsigned integer, encoding a compound term which is a set of the match NOT terms AND length NOT terms.

get()[source]

Get the condition on the terms specifying when the filter is satisfied.

Returns:: and_expression_0, and_not_expression_0, and_expression_1, and_not_expression_1, and_expression_2, and and_expression_3.
Return type:: GetDataAttr

set(and_expression_0, and_not_expression_0, and_expression_1, and_not_expression_1, and_expression_2, and_expression_3)[source]

Set the condition on the terms specifying when the filter is satisfied.

Parameters:

and_expression_0 (int) – encoding a compound term which is a set of the match terms AND length terms.
and_not_expression_0 (int) – encoding a compound term which is a set of the match NOT terms AND length NOT terms.
and_expression_1 (int) – encoding a compound term which is a set of the match terms AND length terms.
and_not_expression_1 (int) – encoding a compound term which is a set of the match NOT terms AND length NOT terms.
and_expression_2 (int) – encoding a compound term which is a set of the match terms AND length terms.
and_expression_3 (int) – encoding a compound term which is a set of the match terms AND length terms.

class PF_CREATE[source]

Bases: object

Creates an empty filter definition with the specified sub-index value.

class SetDataAttr[source]: Bases: RequestBodyStruct

set()[source]: Creates an empty filter definition with the specified sub-index value.

class PF_DELETE[source]

Bases: object

Deletes the filter definition with the specified sub-index value.

class SetDataAttr[source]: Bases: RequestBodyStruct

set()[source]: Delete the filter definition with the specified sub-index value.

class PF_ENABLE[source]

Bases: object

Whether a filter is currently active on a port. While a filter is enabled its condition cannot be changed, nor can any match term or length terms used by it.

class GetDataAttr[source]

Bases: ResponseBodyStruct

on_off: coded byte, whether the filter is enabled.

class SetDataAttr[source]

Bases: RequestBodyStruct

on_off: coded byte, whether the filter is enabled.

get()[source]

Get whether a filter is currently active on the port.

Returns:: whether the filter is enabled
Return type:: PF_ENABLE.GetDataAttr

set(on_off)[source]

Set whether a filter is currently active on the port.

Parameters:: on_off (OnOff) – whether the filter is enabled

set_off(): Disable a filter on a port.

set_on(): Enable a filter on a port.

class PF_INDICES[source]

Bases: object

The full list of which filters are defined for a port. These are the sub-index values that are used for the parameters defining the compound conditions on the match/length terms operating on the packets received for the port. Setting the value of this parameter creates a new empty filter for each value that is not already in use, and deletes each filter that is not mentioned in the list. The same can be accomplished one-filter-at-a-time using the PF_CREATE and PF_DELETE commands.

class GetDataAttr[source]

Bases: ResponseBodyStruct

filter_xindices: list of integers, the list of indices of filters on a port.

class SetDataAttr[source]

Bases: RequestBodyStruct

filter_xindices: list of integers, the list of indices of filters on a port.

get()[source]

Get the full list of which filters are defined for a port.

Returns:: the list of indices of filters on a port
Return type:: PF_INDICES.GetDataAttr

set(filter_xindices)[source]

Create a new empty filter for each index value that is not already in use, and deletes each filter that is not mentioned in the list.

Parameters:: filter_xindices (List[int]) – the list of indices of filters to be created on a port.

class PF_STRING[source]

Bases: object

The string representation of a filter.

class GetDataAttr[source]

Bases: ResponseBodyStruct

string_name: string, the string representation of the filter.

class SetDataAttr[source]

Bases: RequestBodyStruct

string_name: string, the string representation of the filter.

get()[source]

Get the string representation of a filter.

Returns:: the string representation of a filter
Return type:: GetDataAttr

set(string_name)[source]

Set the string representation of a filter.

Parameters:: string_name (str) – the string representation of the filter