Netsend and Netreceive
----------------------

This pair of binaries is used to fixed rate UDP performance testing.

The netreceive tool consists solely of a UDP packet sink bound to a
specified UDP port.  Packets received on its port are copied to user space
and discarded.

The netsend tool acts as a packet source, generating packets of the
specified size at the specified rate to a target IP address and port
number:

   netsend [ip] [port] [payloadsize] [rate] [duration]

The payloadsize field specifies the size of the UDP payload, not the total 
packet size, which will also include a variety of headers (typically, 
ethernet, IP, and UDP).

The rate indicates the number of packets/second to attempt to deliver.

The duration is the duration of the run in seconds.

The netsend tool will wait for around two seconds to synchronize with the
wall clock for timing purposes.  It will then busy-wait between packet
transmits.

The netsend/netreceive tools are under the following copyright and
license:

/*-
 * Copyright (c) 2004 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

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