.\" Copyright (c) 2016 Luigi Rizzo, Universita` di Pisa
.\" All rights reserved.
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.\" $FreeBSD$
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.Dd December 21, 2018
.Dt NMREPLAY 8
.Os
.Sh NAME
.Nm nmreplay
.Nd playback a pcap file through a netmap interface
.Sh SYNOPSIS
.Bk -words
.Bl -tag -width "nmreplay"
.It Nm
.Op Fl f Ar pcap-file
.Op Fl i Ar netmap-interface
.Op Fl B Ar bandwidth
.Op Fl D Ar delay
.Op Fl L Ar loss
.Op Fl b Ar batch size
.Op Fl w Ar wait-link
.Op Fl v
.Op Fl C Ar cpu-placement
.El
.Ek
.Sh DESCRIPTION
.Nm
works like
.Nm tcpreplay
to replay a pcap file through a netmap interface,
with programmable rates and possibly delays, losses
and packet alterations.
.Nm
is designed to run at high speed, so the transmit schedule
is computed ahead of time, and the thread in charge of transmission
only has to pump data through the interface.
.Nm
can connect to any type of netmap port.
.Pp
Command line options are as follows
.Bl -tag -width Ds
.It Fl f Ar pcap-file
Name of the pcap file to replay.
.It Fl i Ar interface
Name of the netmap interface to use as output.
See
.Xr netmap 4
for interface name format.
.It Fl v
Enable verbose mode
.It Fl b Ar batch-size
Maximum batch size to use during transmissions.
.Nm
normally transmits packets one at a time, but it may use
larger batches, up to the value specified with this option,
when running at high rates.
.It Fl B Ar bps | Cm constant , Ns Ar bps | Cm ether , Ns Ar bps | Cm real Ns Op , Ns Ar speedup
Bandwidth to be used for transmission.
.Ar bps
is a floating point number optionally follow by a character
(k, K, m, M, g, G) that multiplies the value by 10^3, 10^6 and 10^9
respectively.
.Cm constant
(can be omitted) means that the bandwidth will be computed
with reference to the actual packet size (excluding CRC and framing).
.Cm ether
indicates that the ethernet framing (160 bits) and CRC (32 bits)
will be included in the computation of the packet size.
.Cm real
means transmission will occur according to the timestamps
recorded in the trace.
The optional
.Ar speedup
multiplier (defaults to 1) indicates how much faster
or slower than real time the trace should be replayed.
.It Fl D Ar dt | Cm constant , Ns Ar dt | Cm uniform , Ns Ar dmin,dmax | Cm exp , Ar dmin,davg
Adds additional delay to the packet transmission, whose distribution
can be constant, uniform or exponential.
.Ar dt, dmin, dmax, avt
are times expressed as floating point numbers optionally followed
by a character (s, m, u, n) to indicate seconds, milliseconds,
microseconds, nanoseconds.
The delay is added to the transmit time and adjusted so that there is
never packet reordering.
.It Fl L Ar x | Cm plr , Ns Ar x | Cm ber , Ns Ar x
Simulates packet or bit errors, causing offending packets to be dropped.
.Ar x
is a floating point number indicating the packet or bit error rate.
.It Fl w Ar wait-link
indicates the number of seconds to wait before transmitting.
It defaults to 2, and may be useful when talking to physical
ports to let link negotiation complete before starting transmission.
.El
.Sh OPERATION
.Nm
creates an in-memory schedule with all packets to be transmitted,
and then launches a separate thread to take care of transmissions
while the main thread reports statistics every second.
.Sh SEE ALSO
.Xr netmap 4
.Sh AUTHORS
.An -nosplit
.Nm
has been written by
.An Luigi Rizzo, Andrea Beconcini, Francesco Mola and Lorenzo Biagini
at the Universita` di Pisa, Italy.