.TH TCPREWRITE 1 2009-02-17 "(tcprewrite )" "Programmer's Manual"
.\"  DO NOT EDIT THIS FILE   (tcprewrite.1)
.\"  
.\"  It has been AutoGen-ed  Tuesday February 17, 2009 at 06:27:05 PM PST
.\"  From the definitions    tcprewrite_opts.def
.\"  and the template file   agman1.tpl
.\"
.SH NAME
tcprewrite \- Rewrite the packets in a pcap file.
.SH SYNOPSIS
.B tcprewrite
.\" Mixture of short (flag) options and long options
.RB [ \-\fIflag\fP " [\fIvalue\fP]]... [" \--\fIopt-name\fP " [[=| ]\fIvalue\fP]]..."
.PP
All arguments must be options.
.SH "DESCRIPTION"
This manual page briefly documents the \fBtcprewrite\fP command.
Tcprewrite is a tool to rewrite packets stored in \fIpcap(3)\fP file format, 
such as crated by tools such as \fItcpdump(1)\fP and \fIethereal(1)\fP.  
Once a pcap file has had it's packets rewritten, they can be replayed back 
out on the network using \fItcpreplay(1)\fP.

tcprewrite currently supports reading the following DLT types:
.sp 1
\fBDLT_C_HDLC\fP aka Cisco HDLC
.sp 1
\fBDLT_EN10MB\fP aka Ethernet
.sp 1
\fBDLT_LINUX_SLL\fP aka Linux Cooked Socket
.sp 1
\fBDLT_RAW\fP aka RAW IP
.sp 1
\fBDLT_NULL\fP aka BSD Loopback
.sp 1
\fBDLT_LOOP\fP aka OpenBSD Loopback
.sp 1
\fBDLT_IEEE802_11\fP aka 802.11a/b/g
.sp 1
\fBDLT_IEEE802_11_RADIO\fP aka 802.11a/b/g with Radiotap headers

Please see the \--dlt option for supported DLT types for writing.

The packet editing features of tcprewrite which distinguish between "client"
and "server" traffic requires a tcpprep(1) cache file.

For more details, please see the Tcpreplay Manual at:
http://tcpreplay.synfin.net/trac/wiki/manual
.SH OPTIONS
.SS ""
.TP
.BR \-r " \fIstring\fP, " \--portmap "=" \fIstring\fP
Rewrite TCP/UDP ports.
This option may appear up to 1 times.
.sp
Specify a list of comma delimited port mappingings consisting of 
colon delimited port number pairs.  Each colon delimited port pair
consists of the port to match followed by the port number to rewrite.

Example:
.nf
    \--portmap=80:8000,8080:80
.fi
.TP
.BR \-s " \fInumber\fP, " \--seed "=" \fInumber\fP
Randomize src/dst IP addresses w/ given seed.
This option may appear up to 1 times.
This option takes an integer number as its argument.
.sp
Causes the source and destination IP addresses to be pseudo 
randomized but still maintain client/server relationships.
Since the randomization is deterministic based on the seed, 
you can reuse the same seed value to recreate the traffic.
.TP
.BR \-N " \fIstring\fP, " \--pnat "=" \fIstring\fP
Rewrite IP addresses using pseudo-NAT.
This option may appear up to 2 times.
This option must not appear in combination with any of the following options:
srcipmap.
.sp
Takes a comma delimited series of colon delimited CIDR
netblock pairs.  Each netblock pair is evaluated in order against
the IP addresses.  If the IP address in the packet matches the
first netblock, it is rewriten using the second netblock as a
mask against the high order bits.

Example:
.nf
    \--pnat=192.168.0.0/16:10.77.0.0/16,172.16.0.0/12:10.1.0.0/24
.fi
.TP
.BR \-S " \fIstring\fP, " \--srcipmap "=" \fIstring\fP
Rewrite source IP addresses using pseudo-NAT.
This option may appear up to 1 times.
This option must not appear in combination with any of the following options:
pnat.
.sp
Works just like the \--pnat option, but only affects the source IP
addresses in the IPv4 header.
.TP
.BR \-D " \fIstring\fP, " \--dstipmap "=" \fIstring\fP
Rewrite destination IP addresses using pseudo-NAT.
This option may appear up to 1 times.
This option must not appear in combination with any of the following options:
pnat.
.sp
Works just like the \--pnat option, but only affects the destination IP
addresses in the IPv4 header.
.TP
.BR \-e " \fIstring\fP, " \--endpoints "=" \fIstring\fP
Rewrite IP addresses to be between two endpoints.
This option may appear up to 1 times.
This option must appear in combination with the following options:
cachefile.
.sp
Takes a pair of colon delimited IP addresses which will be used to rewrite
all traffic to appear to be between the two IP's.

Example:
.nf
    \--endpoints=172.16.0.1:172.16.0.2
.fi
.TP
.BR \-b ", " \--skipbroadcast
Skip rewriting broadcast/multicast IP's.
.sp
By default \--seed, \--pnat and \--endpoints will rewrite 
broadcast and multicast IP and MAC addresses.	Setting this flag
will keep broadcast/multicast IP and MAC addresses from being rewritten.
.TP
.BR \-C ", " \--fixcsum
Force recalculation of IP/TCP/UDP checksums.
.sp
Causes each IP packet to have it's checksums recalcualted and
fixed.  Automatically enabled for packets modified with \fB--seed\fP, 
\fB--pnat\fP, \fB--endpoints\fP or \fB--fixlen\fP.
.TP
.BR \-m " \fInumber\fP, " \--mtu "=" \fInumber\fP
Override default MTU length (1500 bytes).
This option may appear up to 1 times.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  1 through MAXPACKET
.fi
.in -4
.sp
Override the default 1500 byte MTU size for determining the maximum padding length 
(--fixlen=pad) or when truncating (--mtu-trunc).
.TP
.BR \--mtu-trunc
Truncate packets larger then specified MTU.
This option may appear up to 1 times.
.sp
Similar to \--fixlen, this option will truncate data in packets from Layer 3 and above to be 
no larger then the MTU.
.TP
.BR \-E ", " \--efcs
Remove Ethernet checksums (FCS) from end of frames.
.sp
Note, this option is pretty dangerous!  We don't actually check to see if a FCS
actually exists in the frame, we just blindly delete the last two bytes.  Hence,
you should only use this if you know know that your OS provides the FCS when 
reading raw packets.
.TP
.BR \--ttl "=\fIstring\fP"
Modify the IPv4 TTL.
.sp
Allows you to modify the TTL of all the IPv4 packets.  Specify a number to hard-code
the value or +/-value to increase or decrease by the value provided (limited to 1-255).    

Examples:
.nf
    \--ttl=10
    \--ttl=+7
    \--ttl=-64
.fi
.TP
.BR \--tos "=\fInumber\fP"
Set the IPv4 TOS/DiffServ/ECN byte.
This option may appear up to 1 times.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  0 through 255
.fi
.in -4
.sp
Allows you to override the TOS (also known as DiffServ/ECN) value in IPv4 packets.    
.TP
.BR \-F " \fIstring\fP, " \--fixlen "=" \fIstring\fP
Pad or truncate packet data to match header length.
This option may appear up to 1 times.
.sp
Packets may be truncated during capture if the snaplen is smaller then the
packet.  This option allows you to modify the packet to pad the packet back
out to the size stored in the IPv4 header or rewrite the IP header total length
to reflect the stored packet length.
.sp 1
\fBpad\fP
Truncated packets will be padded out so that the packet length matches the 
IPv4 total length
.sp 1
\fBtrunc\fP
Truncated packets will have their IPv4 total length field rewritten to match
the actual packet length
.sp 1
\fBdel\fP
Delete the packet
.TP
.BR \--skipl2broadcast
Skip rewriting broadcast/multicast Layer 2 addresses.
.sp
By default, editing Layer 2 addresses will rewrite 
broadcast and multicast MAC addresses.	Setting this flag
will keep broadcast/multicast MAC addresses from being rewritten.
.TP
.BR \--dlt "=\fIstring\fP"
Override output DLT encapsulation.
This option may appear up to 1 times.
.sp
By default, no DLT (data link type) conversion will be made.  
To change the DLT type of the output pcap, select one of the following values:
.sp 1
\fBenet\fP
Ethernet aka DLT_EN10MB
.sp 1
\fBhdlc\fP
Cisco HDLC aka DLT_C_HDLC
.sp 1
\fBuser\fP
User specified Layer 2 header and DLT type
.br
.TP
.BR \--enet-dmac "=\fIstring\fP"
Override destination ethernet MAC addresses.
This option may appear up to 1 times.
.sp
Takes a pair of comma deliminated ethernet MAC addresses which
will replace the destination MAC address of outbound packets.
The first MAC address will be used for the server to client traffic
and the optional second MAC address will be used for the client
to server traffic.

Example:
.nf
    \--enet-dmac=00:12:13:14:15:16,00:22:33:44:55:66
.fi
.TP
.BR \--enet-smac "=\fIstring\fP"
Override source ethernet MAC addresses.
This option may appear up to 1 times.
.sp
Takes a pair of comma deliminated ethernet MAC addresses which
will replace the source MAC address of outbound packets.
The first MAC address will be used for the server to client traffic
and the optional second MAC address will be used for the client 
to server traffic.

Example:
.nf
    \--enet-smac=00:12:13:14:15:16,00:22:33:44:55:66
.fi
.TP
.BR \--enet-vlan "=\fIstring\fP"
Specify ethernet 802.1q VLAN tag mode.
This option may appear up to 1 times.
.sp
Allows you to rewrite ethernet frames to add a 802.1q header to standard 802.3
ethernet headers or remove the 802.1q VLAN tag information.
.sp 1
\fBadd\fP
Rewrites the existing 802.3 ethernet header as an 802.1q VLAN header
.sp 1
\fBdel\fP
Rewrites the existing 802.1q VLAN header as an 802.3 ethernet header
.TP
.BR \--enet-vlan-tag "=\fInumber\fP"
Specify the new ethernet 802.1q VLAN tag value.
This option may appear up to 1 times.
This option must appear in combination with the following options:
enet-vlan.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  0 through 4095
.fi
.in -4
.sp

.TP
.BR \--enet-vlan-cfi "=\fInumber\fP"
Specify the ethernet 802.1q VLAN CFI value.
This option may appear up to 1 times.
This option must appear in combination with the following options:
enet-vlan.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  0 through 1
.fi
.in -4
.sp

.TP
.BR \--enet-vlan-pri "=\fInumber\fP"
Specify the ethernet 802.1q VLAN priority.
This option may appear up to 1 times.
This option must appear in combination with the following options:
enet-vlan.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  0 through 7
.fi
.in -4
.sp

.TP
.BR \--hdlc-control "=\fInumber\fP"
Specify HDLC control value.
This option may appear up to 1 times.
This option takes an integer number as its argument.
.sp
The Cisco HDLC header has a 1 byte "control" field.  Apparently this should 
always be 0, but if you can use any 1 byte value.
.TP
.BR \--hdlc-address "=\fInumber\fP"
Specify HDLC address.
This option may appear up to 1 times.
This option takes an integer number as its argument.
.sp
The Cisco HDLC header has a 1 byte "address" field which has two valid 
values:
.sp 1
\fB0x0F\fP
Unicast
.sp 1
\fB0xBF\fP
Broadcast
.br
You can however specify any single byte value.
.TP
.BR \--user-dlt "=\fInumber\fP"
Set output file DLT type.
This option may appear up to 1 times.
This option takes an integer number as its argument.
.sp
Set the DLT value of the output pcap file.
.TP
.BR \--user-dlink "=\fIstring\fP"
Rewrite Data-Link layer with user specified data.
This option may appear up to 2 times.
.sp
Provide a series of comma deliminated hex values which will be
used to rewrite or create the Layer 2 header of the packets.
The first instance of this argument will rewrite both server
and client traffic, but if this argument is specified a second
time, it will be used for the client traffic.

Example:
.nf
    \--user-dlink=01,02,03,04,05,06,00,1A,2B,3C,4D,5E,6F,08,00
.fi
.TP
.BR \-d " \fInumber\fP, " \--dbug "=" \fInumber\fP
Enable debugging output.
This option may appear up to 1 times.
This option takes an integer number as its argument.
The value of \fInumber\fP is constrained to being:
.in +4
.nf
.na
in the range  0 through 5
.fi
.in -4
The default \fInumber\fP for this option is:
.ti +4
 0
.sp
If configured with \--enable-debug, then you can specify a verbosity 
level for debugging output.  Higher numbers increase verbosity.
.TP
.BR \-i " \fIstring\fP, " \--infile "=" \fIstring\fP
Input pcap file to be processed.
This option may appear up to 1 times.
.sp

.TP
.BR \-o " \fIstring\fP, " \--outfile "=" \fIstring\fP
Output pcap file.
This option may appear up to 1 times.
.sp

.TP
.BR \-c " \fIstring\fP, " \--cachefile "=" \fIstring\fP
Split traffic via tcpprep cache file.
This option may appear up to 1 times.
.sp
Use tcpprep cache file to split traffic based upon client/server relationships.
.TP
.BR \-v ", " \--verbose
Print decoded packets via tcpdump to STDOUT.
This option may appear up to 1 times.
.sp

.TP
.BR \-A " \fIstring\fP, " \--decode "=" \fIstring\fP
Arguments passed to tcpdump decoder.
This option may appear up to 1 times.
This option must appear in combination with the following options:
verbose.
.sp
When enabling verbose mode (\fB-v\fP) you may also specify one or
more additional arguments to pass to \fBtcpdump\fP to modify
the way packets are decoded.  By default, \-n and \-l are used.
Be sure to quote the arguments so that they are not interpreted
by tcprewrite.   Please see the tcpdump(1) man page for a complete list of 
options.
.TP
.BR \--fragroute "=\fIstring\fP"
Parse fragroute configuration file.
This option may appear up to 1 times.
.sp
Enable advanced evasion techniques using the built-in fragroute(8)
engine.  See the fragroute(8) man page for more details.  Important:
tcprewrite does not support the delay, echo or print commands.    
.TP
.BR \--fragdir "=\fIstring\fP"
Which flows to apply fragroute to: c2s, s2c, both.
This option may appear up to 1 times.
.sp
Apply the fragroute engine to packets going c2s, s2c or both when using a cache file.
.TP
.BR \--skip-soft-errors
Skip writing packets with soft errors.
This option may appear up to 1 times.
.sp
In some cases, packets can't be decoded or the requested editing
is not possible.  Normally these packets are written to the output
file unedited so that tcpprep cache files can still be used, but if
you wish, these packets can be suppressed.

One example of this is 802.11 management frames which contain no data.
.TP
.BR \-V ", " \--version
Print version information.
.sp

.TP
.BR \-h ", " \--less-help
Display less usage information and exit.
.sp

.TP
.BR \-H , " \--help"
Display usage information and exit.
.TP
.BR \-! , " \--more-help"
Extended usage information passed thru pager.
.TP
.BR \- " [\fIrcfile\fP]," " \--save-opts" "[=\fIrcfile\fP]"
Save the option state to \fIrcfile\fP.  The default is the \fIlast\fP
configuration file listed in the \fBOPTION PRESETS\fP section, below.
.TP
.BR \- " \fIrcfile\fP," " \--load-opts" "=\fIrcfile\fP," " \--no-load-opts"
Load options from \fIrcfile\fP.
The \fIno-load-opts\fP form will disable the loading
of earlier RC/INI files.  \fI--no-load-opts\fP is handled early,
out of order.
.SH OPTION PRESETS
Any option that is not marked as \fInot presettable\fP may be preset
by loading values from configuration ("RC" or ".INI") file(s).
The \fIhomerc\fP file is "\fI$$/\fP", unless that is a directory.
In that case, the file "\fI.tcprewriterc\fP"
is searched for within that directory.
.SH "SEE ALSO"
tcpdump(1), tcpprep(1), tcpreplay(1)
.SH AUTHOR
Copyright 2004-2008 Aaron Turner

For support please use the tcpreplay-users@lists.sourceforge.net mailing list.

The latest version of this software is always available from:
http://tcpreplay.synfin.net/
.PP
Released under the Free BSD License.
.PP
This manual page was \fIAutoGen\fP-erated from the \fBtcprewrite\fP
option definitions.