Provided by: freebsd-manpages_6.2-1_all bug


     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.

     Once interface is configured, upon receipt of a NGM_SOURCE_START control
     message the node starts sending the previously queued packets out the
     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 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
     following, which must be sent with the NGM_SOURCE_COOKIE attached.

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

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

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

                     The number of octets queued from the input hook.

                     The number of frames queued from the input hook.

                     The time the last start message was received.

                     The time the last end message was received or the output
                     packet count was reached.

                     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
             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.

     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.


     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


     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 need to be sent to the node, the TCL net package
     can be used to generate these packets:

     [Sandvine specific TCL code example omitted]

     To feed the output of the above TCL script to the source node’s input
     hook via nghook(8):

           tcl genPacket | nghook bge0:orphans input

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

           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

           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 〈