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NG_NETFLOW(4)		     Kernel Interfaces Manual		   NG_NETFLOW(4)

NAME
     ng_netflow -- Cisco's NetFlow implementation

SYNOPSIS
     #include <sys/types.h>
     #include <netinet/in.h>
     #include <netgraph/netflow/ng_netflow.h>

DESCRIPTION
     The  ng_netflow node implements Cisco's NetFlow export protocol on a router
     running FreeBSD.  The ng_netflow node  listens  for  incoming  traffic  and
     identifies  unique flows in it.  Flows are distinguished by endpoint IP ad-
     dresses, TCP/UDP port numbers, ToS and input interface.  Expired flows  are
     exported  out of the node in NetFlow version 5/9 UDP datagrams.  Expiration
     reason can be one of the following:

     -	 RST or FIN TCP segment.

     -	 Active timeout.  Flows cannot live more than the  specified  period  of
	 time.	The default is 1800 seconds (30 minutes).

     -	 Inactive  timeout.   A  flow  was  inactive for the specified period of
	 time.	The default is 15 seconds.

     Node supports IPv6 accounting (NetFlow v9 only) and is  aware  of	multiple
     fibs.   Different	fibs are mapped to different domain_id in NetFlow V9 and
     different engine_id in NetFlow V5.

HOOKS
     This node type supports up to NG_NETFLOW_MAXIFACES  (default  65536)  hooks
     named  iface0, iface1, etc., and the same number of hooks named out0, out1,
     etc., plus two export hooks: export (for NetFlow  version	5)  and  export9
     (for  NetFlow  version  9).  Export can be done simultaneously for all sup-
     ported export hooks. By default (ingress NetFlow enabled) node does NetFlow
     accounting of data received on iface* hooks.  If corresponding out hook  is
     connected,  unmodified data is bypassed to it, otherwise data is freed.  If
     data is received on out hook, it is bypassed to  corresponding  iface  hook
     without any processing (egress NetFlow disabled by default).  When full ex-
     port  datagram  for an export protocol is built it is sent to the export or
     export9 hook.  In normal operation, one (or more) export hook is  connected
     to the inet/dgram/udp hook of the ng_ksocket(4) node.

CONTROL MESSAGES
     This node type supports the generic control messages, plus the following:

     NGM_NETFLOW_INFO
	     Returns  some  node  statistics and the current timeout values in a
	     struct ng_netflow_info.

     NGM_NETFLOW_IFINFO
	     Returns information about the ifaceN  hook.   The	hook  number  is
	     passed as an argument.

     NGM_NETFLOW_SETDLT
	     Sets data link type on the ifaceN hook.  Currently, supported types
	     are  raw  IP datagrams and Ethernet.  This message type uses struct
	     ng_netflow_setdlt as an argument:

		 struct ng_netflow_setdlt {
			 uint16_t iface;	 /* which iface to operate on */
			 uint8_t  dlt;		 /* DLT_XXX from bpf.h */
		 };

	     The requested ifaceN hook must already be connected, otherwise mes-
	     sage send operation will return an error.

     NGM_NETFLOW_SETIFINDEX
	     In some cases, ng_netflow may be unable to determine the input  in-
	     terface  index  of a packet.  This can happen if traffic enters the
	     ng_netflow node before it comes to  the  system  interface's  input
	     queue.   An  example of such a setup is capturing a traffic between
	     synchronous data line and ng_iface(4).  In this case, the input in-
	     dex should be associated with a given hook.  The interface's  index
	     can  be  determined via if_nametoindex(3) from userland.  This mes-
	     sage requires struct ng_netflow_setifindex as an argument:

		 struct ng_netflow_setifindex {
			 u_int16_t iface;	 /* which iface to operate on */
			 u_int16_t index;	 /* new index */
		 };

	     The requested ifaceN hook must already be connected, otherwise  the
	     message send operation will return an error.

     NGM_NETFLOW_SETTIMEOUTS
	     Sets  values in seconds for NetFlow active/inactive timeouts.  This
	     message requires struct ng_netflow_settimeouts as an argument:

		 struct ng_netflow_settimeouts {
			 uint32_t	 inactive_timeout;
			 uint32_t	 active_timeout;
		 };

     NGM_NETFLOW_SETCONFIG
	     Sets configuration for the specified interface.  This  message  re-
	     quires struct ng_netflow_setconfig as an argument:

		 struct ng_netflow_setconfig {
			 u_int16_t iface;
			 u_int32_t conf;
		 #define NG_NETFLOW_CONF_INGRESS	 1
		 #define NG_NETFLOW_CONF_EGRESS 	 2
		 #define NG_NETFLOW_CONF_ONCE		 4
		 #define NG_NETFLOW_CONF_THISONCE	 8
		 };

	     Configuration  is	a  bitmask  of	several  options. Option NG_NET-
	     FLOW_CONF_INGRESS enabled by default enables ingress NetFlow gener-
	     ation  (for  data	coming	from  ifaceX   hook).	Option	 NG_NET-
	     FLOW_CONF_EGRESS  enables egress NetFlow (for data coming from outX
	     hook). Option NG_NETFLOW_CONF_ONCE defines that  packet  should  be
	     accounted	only  once  if it several times passes via netflow node.
	     Option NG_NETFLOW_CONF_THISONCE defines that packet should  be  ac-
	     counted  only once if it several times passes via exactly this net-
	     flow node. Last two options are important to  avoid  duplicate  ac-
	     counting when both ingress and egress NetFlow are enabled.

     NGM_NETFLOW_SETTEMPLATE
	     Sets  various  timeouts  to  announce  data flow templates (NetFlow
	     v9-specific). This message requires  struct  ng_netflow_settemplate
	     as an argument:

		 struct ng_netflow_settemplate {
			 uint16_t time;
			 uint16_t packets;
		 };

	     Value  of time field represents time in seconds to re-announce data
	     templates.  Value of packets field represents maximum packets count
	     between re-announcing data templates.

     NGM_NETFLOW_SETMTU
	     Sets export interface MTU to build packets of specified size  (Net-
	     Flow  v9-specific).  This message requires struct ng_netflow_setmtu
	     as an argument:

		 struct ng_netflow_settemtu {
			 uint16_t mtu;
		 };

	     Default is 1500 bytes

     NGM_NETFLOW_SHOW
	     This control message asks a node to dump the entire contents of the
	     flow cache.  It  is  called  from	flowctl(8),  not  directly  from
	     ngctl(8).	See also "BUGS" section.

ASCII CONTROL MESSAGES
     Most binary control messages have an ASCII equivalent.  The supported ASCII
     commands are:

     NGM_NETFLOW_INFO	      "info"
     NGM_NETFLOW_IFINFO       "ifinfo %u"
     NGM_NETFLOW_SETDLT       "setdlt { iface = %u dlt = %u }"
     NGM_NETFLOW_SETIFINDEX   "setifindex { iface = %u index = %u }"
     NGM_NETFLOW_SETTIMEOUTS  "settimeouts { inactive = %u active = %u }"
     NGM_NETFLOW_SETCONFIG    "setconfig { iface = %u conf = %u }"
     NGM_NETFLOW_SETTEMPLATE  "settemplate { time = %u packets = %u }"
     NGM_NETFLOW_SETMTU       "setmtu { mtu = %u }"

SHUTDOWN
     This  node  shuts	down  upon receipt of a NGM_SHUTDOWN control message, or
     when all hooks have been disconnected.

EXAMPLES
     The simplest possible configuration is one Ethernet interface,  where  flow
     collecting is enabled.

	   /usr/sbin/ngctl -f- <<-SEQ
		   mkpeer fxp0: netflow lower iface0
		   name fxp0:lower netflow
		   connect fxp0: netflow: upper out0
		   mkpeer netflow: ksocket export inet/dgram/udp
		   msg netflow:export connect inet/10.0.0.1:4444
	   SEQ

     This  is  a more complicated example of a router with 2 NetFlow-enabled in-
     terfaces fxp0 and ng0.  Note that the ng0: node in  this  example	is  con-
     nected  to  ng_tee(4).   The latter sends us a copy of IP packets, which we
     analyze and free.	On fxp0: we do not use tee, but  send  packets	back  to
     ether node.

	   /usr/sbin/ngctl -f- <<-SEQ
		   # connect ng0's tee to iface0 hook
		   mkpeer ng0:inet netflow right2left iface0
		   name ng0:inet.right2left netflow
		   # set DLT to raw mode
		   msg netflow: setdlt { iface=0 dlt=12 }
		   # set interface index (5 in this example)
		   msg netflow: setifindex { iface=0 index=5 }

		   # Connect fxp0: to iface1 and out1 hook
		   connect fxp0: netflow: lower iface1
		   connect fxp0: netflow: upper out1

		   # Create ksocket node on export hook, and configure it
		   # to send exports to proper destination
		   mkpeer netflow: ksocket export inet/dgram/udp
		   msg netflow:export connect inet/10.0.0.1:4444
	   SEQ

SEE ALSO
     netgraph(4), setfib(2), ng_ether(4), ng_iface(4), ng_ksocket(4), ng_tee(4),
     flowctl(8), ngctl(8)

     B. Claise, Ed, Cisco Systems NetFlow Services Export Version 9, RFC 3954.

     http://www.cisco.com/en/US/docs/ios/solutions_docs/netflow/nfwhite.html

AUTHORS
     The    ng_netflow	  node	  type	  was	 written    by	 Gleb	Smirnoff
     <glebius@FreeBSD.org>,   Alexander   Motin   <mav@FreeBSD.org>,   Alexander
     Chernikov	<melifaro@ipfw.ru>.   The  initial  code  was based on ng_ipacct
     written by Roman V. Palagin <romanp@unshadow.net>.

BUGS
     Cache snapshot obtained via NGM_NETFLOW_SHOW command may lack some percent-
     age of entries under severe load.	IPv6 flows are not shown.

     The ng_netflow node type does not fill in AS numbers.  This is due  to  the
     lack  of  necessary information in the kernel routing table.  However, this
     information can be injected into the kernel from a routing daemon	such  as
     GNU Zebra.  This functionality may become available in future releases.

FreeBSD 9.0			  March 2, 2011 		   NG_NETFLOW(4)
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