<!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>
