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NG_SOURCE(4)		 BSD Kernel Interfaces Manual		  NG_SOURCE(4)

     ng_source -- netgraph node	for traffic generation

     #include <sys/types.h>
     #include <netgraph/ng_source.h>

     The source	node acts as a source of packets according to the parameters
     set up using control messages and input packets.  The ng_source node type
     is	used primarily for testing and benchmarking.

     The source	node has two hooks: input and output.  The output hook must
     remain connected, its disconnection will shutdown the node.

     The operation of the node is as follows.  Packets received	on the input
     hook are queued internally.  When output hook is connected, ng_source
     node assumes that its neighbour node is of	ng_ether(4) node type.	The
     neighbour is queried for its interface name.  The ng_source node then
     uses queue	of the interface for its evil purposes.	 The ng_source node
     also disables autosrc option on neighbour ng_ether(4) node.  If interface
     name cannot be obtained automatically, it should be configured explicitly
     with the NGM_SOURCE_SETIFACE control message, and autosrc should be
     turned off	on ng_ether(4) node manually.

     If	the node is connected to a netgraph network, which does	not terminate
     in	a real ng_ether(4) interface, limit the	packet injection rate explic-
     itly with the NGM_SOURCE_SETPPS control message.

     Upon receipt of a NGM_SOURCE_START	control	message	the node starts	send-
     ing the previously	queued packets out the output hook on every clock tick
     as	fast as	the connected interface	will take them.	 While active, on ev-
     ery clock tick the	node checks the	available space	in the interface queue
     and sends that many packets out its output	hook.  Once the	number of
     packets indicated in the start message has	been sent, or upon receipt of
     a NGM_SOURCE_STOP message,	the node stops sending data.

     This node type supports the generic control messages as well as the fol-
     lowing, which must	be sent	with the NGM_SOURCE_COOKIE attached.

     NGM_SOURCE_GET_STATS (getstats)
	  Returns a structure containing the following fields:

	  outOctets    The number of octets/bytes sent out the output hook.

	  outFrames    The number of frames/packets sent out the output	hook.

	  queueOctets  The number of octets queued from	the input hook.

	  queueFrames  The number of frames queued from	the input hook.

	  startTime    The time	the last start message was received.

	  endTime      The time	the last end message was received or the out-
		       put packet count	was reached.

	  elapsedTime  Either endTime -	startTime or current time - startTime.

     NGM_SOURCE_CLR_STATS (clrstats)
	  Clears and resets the	statistics returned by getstats	(except
	  queueOctets and queueFrames).

     NGM_SOURCE_GETCLR_STATS (getclrstats)
	  As getstats but clears the statistics	at the same time.

     NGM_SOURCE_START (start)
	  This message requires	a single uint64_t parameter which is the num-
	  ber of packets to send before	stopping.  Node	starts sending the
	  queued packets out the output	hook.  The output hook must be con-
	  nected and node must have interface configured.

     NGM_SOURCE_STOP (stop)
	  Stops	the node if it is active.

     NGM_SOURCE_CLR_DATA (clrdata)
	  Clears the packets queued from the input hook.

     NGM_SOURCE_SETIFACE (setiface)
	  This message requires	the name of the	interface to be	configured as
	  an argument.

     NGM_SOURCE_SETPPS (setpps)
	  This message requires	a single uint32_t parameter which puts upper
	  limit	on the amount of packets sent per second.

     NGM_SOURCE_SET_TIMESTAMP (settimestamp)
	  This message specifies that a	timestamp (in the format of a struct
	  timeval) should be inserted in the transmitted packets.  This	mes-
	  sage requires	a structure containing the following fields:

	  offset  The offset from the beginning	of the packet at which the
		  timestamp is to be inserted.

	  flags	  Set to 1 to enable the timestamp.

     NGM_SOURCE_GET_TIMESTAMP (gettimestamp)
	  Returns the current timestamp	settings in the	form of	the structure
	  described above.

     NGM_SOURCE_SET_COUNTER (setcounter)
	  This message specifies that a	counter	should be embedded in trans-
	  mitted packets.  Up to four counters may be independently config-
	  ured.	 This message requires a structure containing the following

	  offset     The offset	from the beginning of the packet at which the
		     counter is	to be inserted.

	  flags	     Set to 1 to enable	the counter.

	  width	     The byte width of the counter.  It	may be 1, 2, or	4.

	  next_val   The value for the next insertion of the counter.

	  min_val    The minimum value to be used by the counter.

	  max_val    The maximum value to be used by the counter.

	  increment  The value to be added to the counter after	each inser-
		     tion.  It may be negative.

	  index	     The counter to be configured, from	0 to 3.

     NGM_SOURCE_GET_COUNTER (getcounter)
	  This message requires	a single uint8_t parameter which specifies the
	  counter to query.  Returns the current counter settings in the form
	  of the structure described above.

     This node shuts down upon receipt of a NGM_SHUTDOWN control message, when
     all hooks have been disconnected, or when the output hook has been	dis-

     Attach the	node to	an ng_ether(4) node for	an interface.  If ng_ether is
     not already loaded	you will need to do so.	 For example, these commands
     load the ng_ether module and attach the output hook of a new source node
     to	orphans	hook of	the bge0: ng_ether node.

	   kldload ng_ether
	   ngctl mkpeer	bge0: source orphans output

     At	this point the new node	can be referred	to as "bge0:orphans".  The
     node can be given its own name like this:

	   ngctl name bge0:orphans src0

     After which it can	be referred to as "src0:".

     Once created, packets can be sent to the node as raw binary data.	Each
     packet must be delivered in a separate netgraph message.

     The following example uses	a short	Perl script to convert the hex repre-
     sentation of an ICMP packet to binary and deliver it to the source	node's
     input hook	via nghook(8):

	   perl	-pe 's/(..)[ \t\n]*/chr(hex($1))/ge' <<EOF | nghook src0: input
	   ff ff ff ff ff ff 00	00 00 00 00 00 08 00 45	00
	   00 54 cb 13 00 00 40	01 b9 87 c0 a8 2b 65 0a	00
	   00 01 08 00 f8 d0 c9	76 00 00 45 37 01 73 00	01
	   04 0a 08 09 0a 0b 0c	0d 0e 0f 10 11 12 13 14	15
	   16 17 18 19 1a 1b 1c	1d 1e 1f 20 21 22 23 24	25
	   26 27 28 29 2a 2b 2c	2d 2e 2f 30 31 32 33 34	35
	   36 37

     To	check that the node has	queued these packets you can get the node sta-

	   ngctl msg bge0:orphans getstats
	   Args:   { queueOctets=64 queueFrames=1 }

     Send as many packets as required out the output hook:

	   ngctl msg bge0:orphans start	16

     Either wait for them to be	sent (periodically fetching stats if desired)
     or	send the stop message:

	   ngctl msg bge0:orphans stop

     Check the statistics (here	we use getclrstats to also clear the statis-

	   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 } }

     The times are from	struct timevals, the tv_sec field is seconds since the
     Epoch and can be converted	into a date string via TCL's [clock format] or
     via the date(1) command:

	   date	-r 1035305880
	   Tue Oct 22 12:58:00 EDT 2002

     netgraph(4), ng_echo(4), ng_hole(4), ng_tee(4), ngctl(8), nghook(8)

     The ng_source node	type was implemented in	FreeBSD	4.8.

     Dave Chapeskie

BSD			       January 18, 2021				   BSD


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