357 lines
11 KiB
Groff
357 lines
11 KiB
Groff
.\" Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 10, 2012
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.Dt NG_NETFLOW 4
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.Os
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.Sh NAME
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.Nm ng_netflow
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.Nd Cisco's NetFlow implementation
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.Sh SYNOPSIS
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.In sys/types.h
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.In netinet/in.h
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.In netgraph/netflow/ng_netflow.h
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.Sh DESCRIPTION
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The
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.Nm
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node implements Cisco's NetFlow export protocol on a router running
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.Fx .
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The
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.Nm
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node listens for incoming traffic and identifies unique flows in it.
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Flows are distinguished by endpoint IP addresses, TCP/UDP port numbers,
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ToS and input interface.
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Expired flows are exported out of the node in NetFlow version 5/9 UDP datagrams.
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Expiration reason can be one of the following:
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.Bl -dash
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.It
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RST or FIN TCP segment.
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.It
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Active timeout.
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Flows cannot live more than the specified period of time.
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The default is 1800 seconds (30 minutes).
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.It
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Inactive timeout.
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A flow was inactive for the specified period of time.
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The default is 15 seconds.
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.El
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.Pp
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Node supports IPv6 accounting (NetFlow v9 only) and is aware of multiple fibs.
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Different fibs are mapped to different domain_id in NetFlow V9 and different engine_id in NetFlow V5.
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.Sh HOOKS
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This node type supports up to
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.Dv NG_NETFLOW_MAXIFACES
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(default 65536) hooks named
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.Va iface0 , iface1 ,
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etc.,
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and the same number of hooks named
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.Va out0 , out1 ,
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etc.,
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plus two export hooks:
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.Va export
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(for NetFlow version 5) and
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.Va export9
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(for NetFlow version 9). Export can be done simultaneously for all supported
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export hooks. By default (ingress NetFlow enabled) node does NetFlow accounting of data
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received on
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.Va iface*
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hooks.
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If corresponding
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.Va out
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hook is connected, unmodified data is bypassed to it, otherwise data is freed.
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If data is received on
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.Va out
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hook, it is bypassed to corresponding
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.Va iface
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hook without any processing (egress NetFlow disabled by default).
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When full export datagram for an export protocol is built it is sent to the
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.Va export
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or
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.Va export9
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hook.
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In normal operation, one (or more) export hook is connected to the
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.Va inet/dgram/udp
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hook of the
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.Xr ng_ksocket 4
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node.
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.Sh CONTROL MESSAGES
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This node type supports the generic control messages, plus the following:
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.Bl -tag -width foo
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.It Dv NGM_NETFLOW_INFO Pq Ic info
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Returns some node statistics and the current timeout values in a
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.Vt "struct ng_netflow_info" .
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.It Dv NGM_NETFLOW_IFINFO Pq Ic ifinfo
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Returns information about the
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.Va iface Ns Ar N
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hook.
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The hook number is passed as an argument.
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.It Dv NGM_NETFLOW_SETDLT Pq Ic setdlt
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Sets data link type on the
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.Va iface Ns Ar N
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hook.
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Currently, supported types are
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.Cm DLT_RAW
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(raw IP datagrams) and
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.Cm DLT_EN10MB
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(Ethernet).
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DLT_ definitions can be found in
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.In net/bpf.h
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header.
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Currently used values are 1 for
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.Cm DLT_EN10MB
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and 12 for
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.Cm DLT_RAW .
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This message type uses
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.Vt "struct ng_netflow_setdlt"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_setdlt {
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uint16_t iface; /* which iface dlt change */
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uint8_t dlt; /* DLT_XXX from bpf.h */
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};
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.Ed
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.Pp
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The requested
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.Va iface Ns Ar N
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hook must already be connected, otherwise message send operation will
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return an error.
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.It Dv NGM_NETFLOW_SETIFINDEX Pq Ic setifindex
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In some cases,
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.Nm
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may be unable to determine the input interface index of a packet.
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This can happen if traffic enters the
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.Nm
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node before it comes to the system interface's input queue.
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An example of such a setup is capturing a traffic
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.Em between
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synchronous data line and
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.Xr ng_iface 4 .
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In this case, the input index should be associated with a given hook.
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The interface's index can be determined via
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.Xr if_nametoindex 3
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from userland.
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This message requires
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.Vt "struct ng_netflow_setifindex"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_setifindex {
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uint16_t iface; /* which iface index change */
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uint16_t index; /* new index */
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};
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.Ed
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.Pp
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The requested
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.Va iface Ns Ar N
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hook must already be connected, otherwise the message
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send operation will return an error.
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.It Dv NGM_NETFLOW_SETTIMEOUTS Pq Ic settimeouts
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Sets values in seconds for NetFlow active/inactive timeouts.
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This message requires
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.Vt "struct ng_netflow_settimeouts"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_settimeouts {
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uint32_t inactive_timeout; /* flow inactive timeout */
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uint32_t active_timeout; /* flow active timeout */
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};
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.Ed
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.It Dv NGM_NETFLOW_SETCONFIG Pq Ic setconfig
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Sets configuration for the specified interface.
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This message requires
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.Vt "struct ng_netflow_setconfig"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_setconfig {
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uint16_t iface; /* which iface config change */
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uint32_t conf; /* new config */
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#define NG_NETFLOW_CONF_INGRESS 1
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#define NG_NETFLOW_CONF_EGRESS 2
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#define NG_NETFLOW_CONF_ONCE 4
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#define NG_NETFLOW_CONF_THISONCE 8
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#define NG_NETFLOW_CONF_NOSRCLOOKUP 16
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#define NG_NETFLOW_CONF_NODSTLOOKUP 32
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};
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.Ed
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.Pp
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Configuration is a bitmask of several options. Option NG_NETFLOW_CONF_INGRESS
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enabled by default enables ingress NetFlow generation (for data coming from
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ifaceX hook).
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Option
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.Va NG_NETFLOW_CONF_EGRESS
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enables egress NetFlow (for data coming from outX hook).
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Option
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.Va NG_NETFLOW_CONF_ONCE
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defines that packet should be accounted only once if it several times passes
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via netflow node.
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Option
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.Va NG_NETFLOW_CONF_THISONCE
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defines that packet should be accounted only once if it several times passes
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via exactly this netflow node.
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These two options are important to avoid duplicate accounting when both ingress
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and egress NetFlow are enabled.
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Option
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.Va NG_NETFLOW_CONF_NOSRCLOOKUP
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skips radix lookup on flow source address used to fill in network mask.
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Option
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.Va NG_NETFLOW_CONF_NODSTLOOKUP
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skips radix lookup on destination (which fills egress interface id, destination
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mask and gateway).
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If one doesn't need data provided by lookups, he/she can disable them, to reduce
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load on routers.
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.It Dv NGM_NETFLOW_SETTEMPLATE Pq Ic settemplate
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Sets various timeouts to announce data flow templates
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(NetFlow v9-specific). This message requires
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.Vt "struct ng_netflow_settemplate"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_settemplate {
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uint16_t time; /* max time between announce */
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uint16_t packets; /* max packets between announce */
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};
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.Ed
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.Pp
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Value of time field represents time in seconds to re-announce data templates.
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Value of packets field represents maximum packets count between
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re-announcing data templates.
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.It Dv NGM_NETFLOW_SETMTU Pq Ic setmtu
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Sets export interface MTU to build packets of specified size (NetFlow v9-specific).
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This message requires
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.Vt "struct ng_netflow_setmtu"
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as an argument:
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.Bd -literal -offset 4n
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struct ng_netflow_setemtu {
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uint16_t mtu; /* MTU for packet */
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};
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.Ed
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.Pp
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Default is 1500 bytes.
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.It Dv NGM_NETFLOW_SHOW
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This control message asks a node to dump the entire contents of the flow cache.
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It is called from
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.Xr flowctl 8 ,
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not directly from
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.Xr ngctl 8 .
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.It Dv NGM_NETFLOW_V9INFO Pq Ic v9info
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Returns some NetFlow v9 related values in a
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.Bd -literal -offset 4n
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struct ng_netflow_v9info {
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uint16_t templ_packets; /* v9 template packets */
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uint16_t templ_time; /* v9 template time */
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uint16_t mtu; /* v9 MTU */
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};
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.Ed
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of a
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.Dv NGM_SHUTDOWN
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control message, or when all hooks have been disconnected.
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.Sh EXAMPLES
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The simplest possible configuration is one Ethernet interface, where
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flow collecting is enabled.
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.Bd -literal -offset indent
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/usr/sbin/ngctl -f- <<-SEQ
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mkpeer fxp0: netflow lower iface0
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name fxp0:lower netflow
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connect fxp0: netflow: upper out0
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mkpeer netflow: ksocket export inet/dgram/udp
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msg netflow:export connect inet/10.0.0.1:4444
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SEQ
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.Ed
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.Pp
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This is a more complicated example of a router with 2 NetFlow-enabled
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interfaces
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.Li fxp0
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and
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.Li ng0 .
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Note that the
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.Va ng0:
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node in this example is connected to
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.Xr ng_tee 4 .
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The latter sends us a copy of IP packets, which we analyze and free.
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On
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.Va fxp0:
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we do not use tee, but send packets back to either node.
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.Bd -literal -offset indent
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/usr/sbin/ngctl -f- <<-SEQ
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# connect ng0's tee to iface0 hook
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mkpeer ng0:inet netflow right2left iface0
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name ng0:inet.right2left netflow
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# set DLT to raw mode
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msg netflow: setdlt { iface=0 dlt=12 }
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# set interface index (5 in this example)
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msg netflow: setifindex { iface=0 index=5 }
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# Connect fxp0: to iface1 and out1 hook
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connect fxp0: netflow: lower iface1
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connect fxp0: netflow: upper out1
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# Create ksocket node on export hook, and configure it
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# to send exports to proper destination
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mkpeer netflow: ksocket export inet/dgram/udp
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msg netflow:export connect inet/10.0.0.1:4444
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SEQ
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.Ed
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.Sh SEE ALSO
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.Xr netgraph 4 ,
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.Xr setfib 2 ,
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.Xr ng_ether 4 ,
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.Xr ng_iface 4 ,
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.Xr ng_ksocket 4 ,
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.Xr ng_tee 4 ,
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.Xr flowctl 8 ,
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.Xr ngctl 8
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.Rs
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.%A B. Claise, Ed
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.%T "Cisco Systems NetFlow Services Export Version 9"
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.%O RFC 3954
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.Re
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.Pp
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.Pa http://www.cisco.com/en/US/docs/ios/solutions_docs/netflow/nfwhite.html
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm
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node type was written by
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.An Gleb Smirnoff Aq glebius@FreeBSD.org ,
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.An Alexander Motin Aq mav@FreeBSD.org ,
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.An Alexander Chernikov Aq melifaro@ipfw.ru .
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The initial code was based on
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.Nm ng_ipacct
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written by
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.An Roman V. Palagin Aq romanp@unshadow.net .
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.Sh BUGS
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Cache snapshot obtained via
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.Dv NGM_NETFLOW_SHOW
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command may lack some percentage of entries under severe load.
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.Pp
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The
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.Nm
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node type does not fill in AS numbers.
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This is due to the lack of necessary information in the kernel routing table.
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However, this information can be injected into the kernel from a routing daemon
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such as GNU Zebra.
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This functionality may become available in future releases.
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