freebsd-skq/share/man/man4/ng_netflow.4

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.Dd Nov 2, 2012
.Dt NG_NETFLOW 4
.Os
.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 5/9 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
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.
.Sh HOOKS
This node type supports up to
.Dv NG_NETFLOW_MAXIFACES
(default 65536) hooks named
.Va iface0 , iface1 ,
etc.,
and the same number of hooks named
.Va out0 , out1 ,
etc.,
plus two export hooks:
.Va export
(for NetFlow version 5) and
.Va export9
(for NetFlow version 9). Export can be done simultaneously for all supported
export hooks. By default (ingress NetFlow enabled) node does NetFlow accounting of data
received on
.Va iface*
hooks.
If corresponding
.Va out
hook is connected, unmodified data is bypassed to it, otherwise data is freed.
If data is received on
.Va out
hook, it is bypassed to corresponding
.Va iface
hook without any processing (egress NetFlow disabled by default).
When full export datagram for an export protocol is built it is sent to the
.Va export
or
.Va export9
hook.
In normal operation, one (or more) 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 foo
.It Dv NGM_NETFLOW_INFO Pq Ic info
Returns some node statistics and the current timeout values in a
.Vt "struct ng_netflow_info" .
.It Dv NGM_NETFLOW_IFINFO Pq Ic ifinfo
Returns information about the
.Va iface Ns Ar N
hook.
The hook number is passed as an argument.
.It Dv NGM_NETFLOW_SETDLT Pq Ic setdlt
Sets data link type on the
.Va iface Ns Ar N
hook.
Currently, supported types are
.Cm DLT_RAW
(raw IP datagrams) and
.Cm DLT_EN10MB
(Ethernet).
DLT_ definitions can be found in
.In net/bpf.h
header.
Currently used values are 1 for
.Cm DLT_EN10MB
and 12 for
.Cm DLT_RAW .
This message type uses
.Vt "struct ng_netflow_setdlt"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_setdlt {
	uint16_t iface;		/* which iface dlt change */
	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 Pq Ic 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 {
	uint16_t iface;		/* which iface index change */
	uint16_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 Pq Ic 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;	/* flow inactive timeout */
	uint32_t active_timeout;	/* flow active timeout */
};
.Ed
.It Dv NGM_NETFLOW_SETCONFIG Pq Ic setconfig
Sets configuration for the specified interface.
This message requires
.Vt "struct ng_netflow_setconfig"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_setconfig {
	uint16_t iface;		/* which iface config change */
	uint32_t conf;		/* new config */
#define NG_NETFLOW_CONF_INGRESS		1
#define NG_NETFLOW_CONF_EGRESS		2
#define NG_NETFLOW_CONF_ONCE		4
#define NG_NETFLOW_CONF_THISONCE	8
#define NG_NETFLOW_CONF_NOSRCLOOKUP	16
#define NG_NETFLOW_CONF_NODSTLOOKUP	32
};
.Ed
.Pp
Configuration is a bitmask of several options. Option NG_NETFLOW_CONF_INGRESS
enabled by default enables ingress NetFlow generation (for data coming from
ifaceX hook).
Option
.Va NG_NETFLOW_CONF_EGRESS
enables egress NetFlow (for data coming from outX hook).
Option
.Va NG_NETFLOW_CONF_ONCE
defines that packet should be accounted only once if it several times passes
via netflow node.
Option
.Va NG_NETFLOW_CONF_THISONCE
defines that packet should be accounted only once if it several times passes
via exactly this netflow node.
These two options are important to avoid duplicate accounting when both ingress
and egress NetFlow are enabled.
Option
.Va NG_NETFLOW_CONF_NOSRCLOOKUP
skips radix lookup on flow source address used to fill in network mask.
Option
.Va NG_NETFLOW_CONF_NODSTLOOKUP
skips radix lookup on destination (which fills egress interface id, destination
mask and gateway).
If one doesn't need data provided by lookups, he/she can disable them, to reduce
load on routers.
.It Dv NGM_NETFLOW_SETTEMPLATE Pq Ic settemplate
Sets various timeouts to announce data flow templates
(NetFlow v9-specific). This message requires
.Vt "struct ng_netflow_settemplate"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_settemplate {
	uint16_t time;		/* max time between announce */
	uint16_t packets;	/* max packets between announce */
};
.Ed
.Pp
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.
.It Dv NGM_NETFLOW_SETMTU Pq Ic setmtu
Sets export interface MTU to build packets of specified size (NetFlow v9-specific).
This message requires
.Vt "struct ng_netflow_setmtu"
as an argument:
.Bd -literal -offset 4n
struct ng_netflow_setemtu {
	uint16_t mtu;		/* MTU for packet */
};
.Ed
.Pp
Default is 1500 bytes.
.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 .
See also
.Sx BUGS
section.
.It Dv NGM_NETFLOW_V9INFO Pq Ic v9info
Returns some NetFlow v9 related values in a
.Bd -literal -offset 4n
struct ng_netflow_v9info {
    uint16_t        templ_packets;  /* v9 template packets */
    uint16_t        templ_time;     /* v9 template time */
    uint16_t        mtu;            /* v9 MTU */
};
.Ed
.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: 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
.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 .
The latter sends us a copy of IP packets, which we analyze and free.
On
.Va fxp0:
we do not use tee, but send packets back to either node.
.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 }

	# 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
.Ed
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr setfib 2 ,
.Xr ng_ether 4 ,
.Xr ng_iface 4 ,
.Xr ng_ksocket 4 ,
.Xr ng_tee 4 ,
.Xr flowctl 8 ,
.Xr ngctl 8
.Rs
.%A B. Claise, Ed
.%T "Cisco Systems NetFlow Services Export Version 9"
.%O RFC 3954
.Re
.Pp
.Pa http://www.cisco.com/en/US/docs/ios/solutions_docs/netflow/nfwhite.html
.Sh AUTHORS
.An -nosplit
The
.Nm
node type was written by
.An Gleb Smirnoff Aq glebius@FreeBSD.org ,
.An Alexander Motin Aq mav@FreeBSD.org ,
.An Alexander Chernikov Aq melifaro@ipfw.ru .
The initial code was based on
.Nm ng_ipacct
written by
.An Roman V. Palagin Aq romanp@unshadow.net .
.Sh BUGS
Cache snapshot obtained via
.Dv NGM_NETFLOW_SHOW
command may lack some percentage of entries under severe load.
IPv6 flows are not shown.
.Pp
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.