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<!DOCTYPE refentry PUBLIC "-//Davenport//DTD DocBook V3.0//EN">
<refentry>
<refmeta>
<refentrytitle>
<application>flow-nfilter</application>
</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>
<application>flow-nfilter</application>
</refname>
<refpurpose>
Filter flows.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>flow-nfilter</command>
<arg>-hk</arg>
<arg>-b<replaceable> big</replaceable>|<replaceable>little</replaceable></arg>
<arg>-C<replaceable> comment</replaceable></arg>
<arg>-d<replaceable> debug_level</replaceable></arg>
<arg>-f<replaceable> filter_fname</replaceable></arg>
<arg>-F<replaceable> filter_definition</replaceable></arg>
<arg>-v<replaceable> variable binding</replaceable></arg>
<arg>-z<replaceable> z_level</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>DESCRIPTION</title>
<para>
The <command>flow-nfilter</command> utility will filter flows based on
user selectable criteria. Filters are defined in a configuration file
and are composed of primitives and a definition. Definitions contain
match lines grouped to form logical AND and OR operations on the flow
using the selected primitives. A definition may contain the invert
command which will invert the result of the evaluation.
</para>
<para>
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.
</para>
<para>
Filter primitives begin with the filter-primitive keyword followed by
a symbolic name. Each primitive has a type defined below.
A list of permit and or deny keywords followed
by an argument are later evaulated to determine if the flow is permitted or
denied. The default action for a primitive is to deny which may be
changed with the default keyword. Symbolic substitutions are done where
appropriate.
</para>
<para>
</para>
<para>
The match keyword in a definition selects the criteria to match a primitive.
A match type may allow more than one type of primitive, for example the
src-ip-addr match type will accept any of {ip-address, ip-address-mask,
ip-address-prefix} primitive types.
</para>
<para>
<screen>
Primitive type Type Description/Example
-------------------------------------------------------------------
as Bucket Autonomous System Number.
600,159,3112
ip-address-prefix-len Numeric Integer from 0 to 32.
16-31
ip-protocol Bucket Integer from 0 to 255.
6,17,1
ip-tos Bucket Integer from 0 to 255 with mask.
0xA0/0xE0
ip-tcp-flags Bucket Integer from 0 to 255 with mask.
0x2/0x2
ifindex Bucket Integer from 0 to 65535
0,5,10
engine Bucket Integer from 0 to 255.
0
ip-port Bucket Integer from 0 to 65535.
80,8080,23,22
ip-address Hash List of IP Addresses.
10.0.0.1
ip-address-mask List List of IP address/mask pairs.
10.1.0.0 255.255.0.0
ip-address-prefix Trie List of IP address/mask pairs.
10.1/16
tag Hash List of tags.
0xFF00
tag-mask List List of tags.
0xF000/0xFF00
counter List List of Integers with qualifier.
lt 32
time List List of relative time specifiers.
gt 5:00
time-date List List of absolute time specifiers.
gt December 12, 2002 5:13:21
double List List of doubles with qualifier.
lt 32.0
rate Element Rate is calculated as 1/rate.
permit 100
Match type Description Primitives accepted
-------------------------------------------------------------------
source-as Source AS as
destination-as Destination AS as
ip-source-address Source IP Address ip-address,
ip-address-mask,
ip-address-prefix
ip-destination-address Destination IP Address ip-address,
ip-address-mask,
ip-address-prefix
ip-exporter-address Exporter IP Address ip-address,
ip-address-mask,
ip-address-prefix
ip-nexthop-address NextHop IP Address ip-address,
ip-address-mask,
ip-address-prefix
ip-shortcut-address Shortcut IP Address ip-address,
ip-address-mask,
ip-address-prefix
ip-protocol IP Protocol ip-protocol
ip-source-address-prefix-len
Source IP address ip-address-prefix-len
prefix length
ip-destination-address-prefix-len
Destination IP address ip-address-prefix-len
prefix length
ip-tos IP Type Of Service ip-tos
ip-marked-tos IP Type Of Service ip-tos
ip-tcp-flags IP/TCP Flags ip-tcp-flags
ip-source-port Source IP Port ip-port
eg TCP/UDP
ip-destination-port Destination IP Port ip-port
eg TCP/UDP
input-interface Source ifIndex ifindex
eg Input Interface
output-interface Destination ifIndex ifindex
eg Output Interface
start-time Start Time of flow time, time-date
end-time End Time of Flow time, time-date
flows Number of flows counter
octets Number of octets counter
packets Number of packets counter
duration Duration of flow in ms counter
engine-id Engine ID engine
engine-type Engine Type engine
source-tag Source Tag tag, tag-mask
destination-tag Destination Tag tag, tag-mask
pps Packets Per Second double
bps Bits Per Second double
random-sample Random Sample rate
</screen>
</para>
</refsect1>
<refsect1>
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term>-b<replaceable> big</replaceable>|<replaceable>little</replaceable</term>
<listitem>
<para>
Byte order of output.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-C<replaceable> Comment</replaceable></term>
<listitem>
<para>
Add a comment.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-d<replaceable> debug_level</replaceable></term>
<listitem>
<para>
Enable debugging.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-f<replaceable> filter_fname</replaceable></term>
<listitem>
<para>
Filter list filename. Defaults to <filename>@localstatedir@/cfg/filter</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-F<replaceable> filter_definition</replaceable></term>
<listitem>
<para>
Select the active definition. Defaults to default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-h</term>
<listitem>
<para>
Display help.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-k</term>
<listitem>
<para>
Keep time from input.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-v<replaceable> variable binding</replaceable></term>
<listitem>
<para>
Set a variable FOO=bar.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-z<replaceable> z_level</replaceable></term>
<listitem>
<para>
Configure compression level to <replaceable> z_level</replaceable>. 0 is
disabled (no compression), 9 is highest compression.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>TIME/DATE parsing</title>
<para>
time-date parsing is implemented with <filename>getdate.y</filename>,
a commonly used function to process free-form time date specifications.
Example usage borrowed from <command>cvs</command>:
1 month ago
2 hours ago
400000 seconds ago
last year
last Monday
yesterday
a fortnight ago
3/31/92 10:00:07 PST
January 23, 1987 10:05pm
22:00 GMT
</para>
</refsect1>
<refsect1>
<title>EXAMPLES</title>
<informalexample>
<para>
An example of filter configuration file.
<screen>
filter-primitive srate
type rate
permit 100
filter-primitive test-as
type as
permit 600,159
filter-primitive test-prefix-len
type ip-address-prefix-len
permit 32
filter-primitive test-protocol
type ip-protocol
permit tcp
filter-primitive test-tos
type ip-tos
mask 0xA0
permit 0xE0
filter-primitive test-tcp-flags
type ip-tcp-flags
mask 0x2
permit 0x2
filter-primitive test-ifindex
type ifindex
permit 0,5,10
filter-primitive test-engine
type engine
permit 0
filter-primitive test-port
type ip-port
permit https
permit 80
default deny
filter-primitive test-address
type ip-address
permit 0.0.0.1
permit 0.0.0.2
default deny
filter-primitive test-address-mask
type ip-address-mask
permit 128.146.197.1 255.255.255.255
permit 128.146.197.2 255.255.255.255
filter-primitive test-prefix
type ip-address-prefix
permit 128.146.0.0/16
default deny
filter-primitive test-tag
type tag
permit 0x00
permit 0x01
permit 0xFF
filter-primitive test-tag-mask
type tag-mask
permit OSU 0xFF
permit 0xFF 0xFF
default deny
filter-primitive test-counter
type counter
permit lt 5
permit gt 10
default deny
filter-primitive test-time-date
type time-date
permit gt December 12, 2002 5:13:21
filter-primitive test-time
type time-date
permit gt 12:15:00
filter-definition sample-1-in-100
match random-sample srate
filter-definition t1
match engine-type test-engine
or
match destination-tag test-tag-mask
</screen>
</para>
</informalexample>
<informalexample>
<para>
Display all flows with a destination port of 80 or source port of 25 (smtp)
starting after Dec 12, 2001. The file <filename>test</filename> is
populated with the following:
<literallayout>
filter-primitive port80
type ip-port
permit 80
filter-primitive port25
type ip-port
permit smtp
filter-primitive dec12
type time-date
permit gt Dec 12, 2001
filter-definition foo
match ip-source-port port80
match start-time dec12
or
match ip-destination-port port25
match start-time dec12
</literallayout>
<command>flow-cat <filename>flows</filename> | flow-nfilter -ftest -Ffoo | flow-print</command>
</para>
</informalexample>
</refsect1>
<refsect1>
<title>FILES</title>
<para>
Configuration files:
Symbols - <filename>@localstatedir@/sym/*</filename>.
Tag - <filename>@localstatedir@/cfg/tag.cfg</filename>.
Filter - <filename>@localstatedir@/cfg/filter.cfg</filename>.
</para>
</refsect1>
<refsect1>
<title>BUGS</title>
<para>
None known.
</para>
</refsect1>
<refsect1>
<title>AUTHOR</title>
<para>
<author>
<firstname>Mark</firstname>
<surname>Fullmer</surname>
</author>
<email>maf@splintered.net</email>
</para>
</refsect1>
<refsect1>
<title>SEE ALSO</title>
<para>
<application>flow-tools</application>(1)
</para>
</refsect1>
</refentry>
|
