freebsd-nq/share/man/man4/ng_source.4

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.\" Author: Dave Chapeskie <dchapeskie@sandvine.com>
.\" $FreeBSD$
.\"
.Dd April 5, 2005
.Dt NG_SOURCE 4
.Os
.Sh NAME
.Nm ng_source
.Nd netgraph node for traffic generation
.Sh SYNOPSIS
.In sys/types.h
.In netgraph/ng_source.h
.Sh DESCRIPTION
The
.Nm source
node acts as a source of packets according to the parameters set up
using control messages and input packets.
The
.Nm
node type is used primarily for testing and benchmarking.
.Sh HOOKS
The
.Nm source
node has two hooks:
.Va input
and
.Va output .
The
.Va output
hook must remain connected, its disconnection will shutdown the node.
.Sh OPERATION
The operation of the node is as follows.
Packets received on the
.Va input
hook are queued internally.
When 
.Va output
hook is connected,
.Nm
node assumes that its neighbour node is of
.Xr ng_ether
node type.
The neighbor is queried for its interface name.
.Nm
node then uses queue of the interface for its evil purposes.
.Nm
node also disables
.Va autosrc
option on neighbour
.Xr ng_ether
node.
If interface name can't be obtained automatically, it should
be configured explicitly with help of
.Dv NGM_SOURCE_SETIFACE 
control message, and
.Va autosrc
should be turned off on
.Xr ng_ether
node manually.
.Pp
Once interface is configured, upon receival of
.Dv NGM_SOURCE_START
control message the node starts sending
the previously queued packets out the
.Va output
hook on every clock tick as fast
as the connected interface will take them.
While active, on every clock tick the node checks the available space
in the interface queue and sends that many packets out its
.Va output
hook.
Once the number of packets indicated in the start message have been
sent, or upon reception of a stop message, the node stops sending data.
.Sh CONTROL MESSAGES
This node type supports the generic control messages as well as the following,
which must be sent with the
.Dv NGM_SOURCE_COOKIE
attached.
.Bl -tag -width indent
.It Dv NGM_SOURCE_GET_STATS Pq Ic getstats
Returns a structure containing the following fields:
.Bl -tag -width indent
.It Va outOctets
The number of octets/bytes sent out the
.Dv output
hook.
.It Va outFrames
The number of frames/packets sent out the
.Dv output
hook.
.It Va queueOctets
The number of octets queued from the
.Dv input
hook.
.It Va queueFrames
The number of frames queued from the
.Dv input
hook.
.It Va startTime
The time the last start message was received.
.It Va endTime
The time the last end message was received or
the output packet count was reached.
.It Va elapsedTime
Either
.Va endTime Li \- Va startTime
or current time
\-
.Va startTime .
.El
.It Dv NGM_SOURCE_CLR_STATS Pq Ic clrstats
Clears and resets the statistics returned by
.Ic getstats
(except
.Va queueOctets
and
.Va queueFrames ) .
.It Dv NGM_SOURCE_GETCLR_STATS Pq Ic getclrstats
As
.Ic getstats
but clears the statistics at the same time.
.It Dv NGM_SOURCE_START Pq Ic start
This message requires a single
.Vt uint64_t
parameter which is the number of packets to
send before stopping.
Node starts sending the queued packets out the output hook.
The output hook must be connected and node must have
interface configured.
.It Dv NGM_SOURCE_STOP Pq Ic stop
Stops the node if it is active.
.It Dv NGM_SOURCE_CLR_DATA Pq Ic clrdata
Clears the packets queued from the
.Dv input
hook.
.It Dv NGM_SOURCE_SETIFACE Pq Ic setiface
This message requires a string argument - name of the interface
to be configured.
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, when all hooks has been disconnected, or when the
.Va output
hook has been disconnected.
.Sh EXAMPLES
Attach the node to an
.Xr ng_ether 4
node for an interface.
If
.Nm ng_ether
is
not already loaded you will need to do so.
For example, these commands
load the
.Nm ng_ether
module and attach the
.Dv output
hook of a new
.Nm source
node to
.Dv orphans
hook of the
.Li bge0:
.Nm ng_ether
node.
.Bd -literal -offset indent
kldload ng_ether
ngctl mkpeer bge0: source orphans output
.Ed
.Pp
At this point the new node can be referred to as
.Dq Li bge0:orphans .
The
node can be given its own name like this:
.Pp
.Dl "ngctl name bge0:orphans src0"
.Pp
After which it can be referred to as
.Dq Li src0: .
.Pp
Once created, packets need to be sent to the node, the TCL net package
can be used to generate these packets:
.Pp
[Sandvine specific TCL code example omitted]
.Pp
To feed the output of the above TCL script to the
.Nm source
node's
.Dv input
hook via
.Xr nghook 8 :
.Pp
.Dl "tcl genPacket | nghook bge0:orphans input"
.Pp
To check that the node has queued these packets you can get the node
statistics:
.Bd -literal -offset indent
ngctl msg bge0:orphans getstats
Args:   { queueOctets=64 queueFrames=1 }
.Ed
.Pp
Send as many packets as required out the
.Dv output
hook:
.Pp
.Dl "ngctl msg bge0:orphans start 16"
.Pp
Either wait for them to be sent (periodically fetching stats if desired)
or send the stop message:
.Pp
.Dl "ngctl msg bge0:orphans stop"
.Pp
Check the statistics (here we use
.Ic getclrstats
to also clear the statistics):
.Bd -literal -offset indent
ngctl msg bge0:orphans getclrstats
Args:   { outOctets=1024 outFrames=16 queueOctets=64 queueFrames=1
startTime={ tv_sec=1035305880 tv_usec=758036 } endTime={ tv_sec=1035305880
tv_usec=759041 } elapsedTime={ tv_usec=1005 } }
.Ed
.Pp
The times are from
.Vt "struct timeval" Ns s ,
the
.Va tv_sec
field is seconds since
the Epoch and can be converted into a date string via TCL's [clock
format] or via the
.Xr date 1
command:
.Bd -literal -offset indent
date -r 1035305880
Tue Oct 22 12:58:00 EDT 2002
.Ed
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_echo 4 ,
.Xr ng_hole 4 ,
.Xr ng_tee 4 ,
.Xr ngctl 8 ,
.Xr nghook 8
.Sh HISTORY
The
.Nm
node type was implemented in
.Fx 4.8 .
.Sh AUTHORS
.An Dave Chapeskie Aq dchapeskie@SANDVINE.com