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.Dd September 17, 2004
.Os
.Dt NG_NETFLOW 4
.Sh NAME
.Nm ng_netflow
.Nd Cisco's NetFlow implementation
.Sh SYNOPSIS
.In sys/types.h
.In netinet/in.h
.In netgraph/netflow/ng_netflow.h
.Sh DESCRIPTION
The
.Nm
node implements Cisco's NetFlow export protocol on a router running
.Fx .
The
.Nm
node listens for incoming traffic and identifies unique flows in it.
Flows are distinguished by endpoint IP addresses, TCP/UDP port numbers,
ToS and input interface.
Expired flows are exported out of the node in NetFlow version 5 UDP datagrams.
Expiration reason can be one of the following:
.Bl -dash
.It
RST or FIN TCP segment.
.It
Active timeout.
Flows cannot live more than the specified period of time.
The default is 1800 seconds (30 minutes).
.It
Inactive timeout.
A flow was inactive for the specified period of time.
The default is 15 seconds.
.El
.Pp
Export information is stored in NetFlow version 5 datagrams.
.Sh HOOKS
This node type supports up to
.Dv NG_NETFLOW_MAXIFACES
hooks named
.Va iface0 , iface1 ,
etc.,
plus a single hook named
.Va export .
The node reads data on
.Va iface*
hooks, and sends export datagrams to the
.Va export
hook.
In normal operation, the
.Va export
hook is connected to the
.Va inet/dgram/udp
hook of the
.Xr ng_ksocket 4
node.
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width indent
.It Dv NGM_NETFLOW_INFO
Returns some node statistics and the current timeout values in a
.Vt "struct ng_netflow_info" .
.It Dv NGM_NETFLOW_IFINFO
Returns information about the
.Va iface Ns Ar N
hook.
The hook number is passed as an argument.
.It Dv NGM_NETFLOW_SETDLT
Sets data link type on the
.Va iface Ns Ar N
hook.
Currently, supported types are raw IP datagrams and Ethernet.
This messsage type uses
.Vt "struct ng_netflow_setdlt"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_setdlt {
	uint16_t iface;		/* which iface to operate on */
	uint8_t  dlt;		/* DLT_XXX from bpf.h */
};
.Ed
.Pp
The requested
.Va iface Ns Ar N
hook must already be connected, otherwise message send operation will
return an error.
.It Dv NGM_NETFLOW_SETIFINDEX
In some cases,
.Nm
may be unable to determine the input interface index of a packet.
This can happen if traffic enters the
.Nm
node before it comes to the system interface's input queue.
An example of such a setup is capturing a traffic
.Em between
synchronous data line and
.Xr ng_iface 4 .
In this case, the input index should be associated with a given hook.
The interface's index can be determined via
.Xr if_nametoindex 3
from userland.
This message requires
.Vt "struct ng_netflow_setifindex"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_setifindex {
	u_int16_t iface;	/* which iface to operate on */
	u_int16_t index;	/* new index */
};
.Ed
.Pp
The requested
.Va iface Ns Ar N
hook must already be connected, otherwise the message
send operation will return an error.
.It Dv NGM_NETFLOW_SETTIMEOUTS
Sets values in seconds for NetFlow active/inactive timeouts.
This message requires
.Vt "struct ng_netflow_settimeouts"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_settimeouts {
	uint32_t	inactive_timeout;
	uint32_t	active_timeout;
};
.Ed
.It Dv NGM_NETFLOW_SHOW
This control message asks a node to dump the entire contents of the flow cache.
It is called from
.Xr flowctl 8 ,
not directly from
.Xr ngctl 8 .
.El
.Sh ASCII CONTROL MESSAGES
Most binary control messages have an
.Tn ASCII
equivalent.
The supported
.Tn ASCII
commands are:
.Pp
.Bl -tag -width ".Dv NGM_NETFLOW_SETTIMEOUTS" -compact
.It Dv NGM_NETFLOW_INFO
.Qq Li info
.It Dv NGM_NETFLOW_IFINFO
.Qq Li "ifinfo %u"
.It Dv NGM_NETFLOW_SETDLT
.Qq Li "setdlt { iface = %u dlt = %u }"
.It Dv NGM_NETFLOW_SETIFINDEX
.Qq Li "setifindex { iface = %u index = %u }"
.It Dv NGM_NETFLOW_SETTIMEOUTS
.Qq Li "settimeouts { inactive = %u active = %u }"
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, or when all hooks have been disconnected.
.Sh EXAMPLES
The simplest possible configuration is one Ethernet interface, where
flow collecting is enabled.
.Bd -literal -offset indent
/usr/sbin/ngctl -f- <<-SEQ
	mkpeer fxp0: tee lower right
	connect fxp0: fxp0:lower upper left
	mkpeer fxp0:lower netflow right2left iface0
	name fxp0:lower.right2left netflow
	mkpeer netflow: ksocket export inet/dgram/udp
	msg netflow:export connect inet/10.0.0.1:4444
SEQ
.Ed
.Pp
This is a more complicated example of a router with 2 NetFlow-enabled
interfaces
.Li fxp0
and
.Li ng0 .
Note that the
.Va ng0:
node in this example is connected to
.Xr ng_tee 4 .
.Bd -literal -offset indent
/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 }

	# Create tee on fxp0, and connect it to iface1 hook
	mkpeer fxp0: tee lower right
	connect fxp0: fxp0:lower upper left
	name fxp0:lower fxp0_tee
	connect fxp0_tee: netflow: right2left iface1

	# 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
.Ed
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_ksocket 4 ,
.Xr ng_tee 4 ,
.Xr ngctl 8
.Pp
.Pa http://www.cisco.com/warp/public/cc/pd/iosw/ioft/neflct/tech/napps_wp.htm
.Sh AUTHORS
.An -nosplit
The
.Nm
node type was written by
.An Gleb Smirnoff Aq glebius@FreeBSD.org ,
based on
.Nm ng_ipacct
written by
.An Roman V. Palagin Aq romanp@unshadow.net .
.Sh BUGS
The
.Nm
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.