Ubuntu Manpage: tcprewrite - Rewrite the packets in a pcap file.

NAME

       tcprewrite - Rewrite the packets in a pcap file.

SYNOPSIS

       tcprewrite [-flags] [-flag [value]] [--option-name[[=| ]value]]

       All arguments must be options.

DESCRIPTION

       Tcprewrite  is a tool to rewrite packets stored in pcap(3) file format, such as created by
       tools such as tcpdump(1) and  wireshark(1).   Once  a  pcap  file  has  had  it's  packets
       rewritten, they can be replayed back out on the network using tcpreplay(1).

       tcprewrite currently supports reading the following DLT types:

       DLT_C_HDLC aka Cisco HDLC

       DLT_EN10MB aka Ethernet

       DLT_LINUX_SLL aka Linux Cooked Socket

       DLT_LINUX_SLL2 aka Linux Cooked Socket v2

       DLT_RAW aka RAW IP

       DLT_NULL aka BSD Loopback

       DLT_LOOP aka OpenBSD Loopback

       DLT_IEEE802_11 aka 802.11a/b/g

       DLT_IEEE802_11_RADIO aka 802.11a/b/g with Radiotap headers

       DLT_JUNIPER_ETHER aka Juniper Encapsulated Ethernet

       DLT_PPP_SERIAL aka PPP over Serial

       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.appneta.com

OPTIONS

-r string, --portmap=string
Rewrite TCP/UDP ports. This option may appear up to 9999 times.

Specify a list of comma delimited port mappings 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.

Examples:
--portmap=80:8000 --portmap=8080:80 # 80->8000 and 8080->80
--portmap=8000,8080,88888:80 # 3 different ports become 80
--portmap=8000-8999:80 # ports 8000 to 8999 become 80

-s number, --seed=number
Randomize src/dst IPv4/v6 addresses w/ given seed. This option may appear up to 1
times. This option must not appear in combination with any of the following
options: fuzz-seed. This option takes an integer number as its argument.

Causes the source and destination IPv4/v6 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.

-N string, --pnat=string
Rewrite IPv4/v6 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.

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 rewritten using the second netblock as
a mask against the high order bits.

IPv4 Example:
--pnat=192.168.0.0/16:10.77.0.0/16,172.16.0.0/12:10.1.0.0/24
IPv6 Example:
--pnat=[2001:db8::/32]:[dead::/16],[2001:db8::/32]:[::ffff:0:0/96]

-S string, --srcipmap=string
Rewrite source IPv4/v6 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.

Works just like the --pnat option, but only affects the source IP addresses in the
IPv4/v6 header.

-D string, --dstipmap=string
Rewrite destination IPv4/v6 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.

Works just like the --pnat option, but only affects the destination IP addresses in
the IPv4/v6 header.

-e string, --endpoints=string
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.

Takes a pair of colon delimited IPv4/v6 addresses which will be used to rewrite all
traffic to appear to be between the two IP addresses.

IPv4 Example:
--endpoints=172.16.0.1:172.16.0.2
IPv6 Example:
--endpoints=[2001:db8::dead:beef]:[::ffff:0:0:ac:f:0:2]

--tcp-sequence=number
Change TCP Sequence (and ACK) numbers /w given seed. This option takes an integer
number as its argument. The value of number is constrained to being:
greater than or equal to 1
The default number for this option is:
0

Change all TCP sequence numbers, and related sequence-acknowledgement numbers.
They will be shifted by a random amount based on the provided seed.

-b, --skipbroadcast
Skip rewriting broadcast/multicast IPv4/v6 addresses.

By default --seed, --pnat and --endpoints will rewrite broadcast and multicast
IPv4/v6 and MAC addresses. Setting this flag will keep broadcast/multicast IPv4/v6
and MAC addresses from being rewritten.

-C, --fixcsum
Force recalculation of IPv4/TCP/UDP header checksums.

Causes each IPv4/v6 packet to have their checksums recalculated and fixed.
Automatically enabled for packets modified with --seed, --pnat, --endpoints or
--fixlen.

--fixhdrlen
Alter IP/TCP header len to match packet length.

By default, tcpreplay will send packets with the original packet length, However,
you may want the packet length revised to minimum packet size. Using this option,
tcpreplay will rewrite (fix) the packet length, and recalculate checksums when
packet length changes. Caution: undesired packet changes may occur when this
option is specified.

-m number, --mtu=number
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 number is
constrained to being:
in the range 1 through MAX_SNAPLEN

Override the default 1500 byte MTU size for determining the maximum padding length
(--fixlen=pad) or when truncating (--mtu-trunc).

--mtu-trunc
Truncate packets larger then specified MTU. This option may appear up to 1 times.

Similar to --fixlen, this option will truncate data in packets from Layer 3 and
above to be no larger then the MTU.

-E, --efcs
Remove Ethernet checksums (FCS) from end of frames.

Note, this option is pretty dangerous! We do not actually check to see if a FCS
actually exists in the frame, we just blindly delete the last 4 bytes. Hence, you
should only use this if you know know that your OS provides the FCS when reading
raw packets.

--ttl=string
Modify the IPv4/v6 TTL/Hop Limit.

Allows you to modify the TTL/Hop Limit of all the IPv4/v6 packets. Specify a
number to hard-code the value or +/-value to increase or decrease by the value
provided (limited to 1-255).

Examples:
--ttl=10
--ttl=+7
--ttl=-64

--tos=number
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 number is constrained
to being:
in the range 0 through 255

Allows you to override the TOS (also known as DiffServ/ECN) value in IPv4.

--tclass=number
Set the IPv6 Traffic Class byte. This option may appear up to 1 times. This
option takes an integer number as its argument. The value of number is constrained
to being:
in the range 0 through 255

Allows you to override the IPv6 Traffic Class field.

--flowlabel=number
Set the IPv6 Flow Label. This option may appear up to 1 times. This option takes
an integer number as its argument. The value of number is constrained to being:
in the range 0 through 1048575

Allows you to override the 20bit IPv6 Flow Label field. Has no effect on IPv4
packets.

-F string, --fixlen=string
Pad or truncate packet data to match header length. This option may appear up to 1
times.

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/v6 header or rewrite the IP header total length to reflect the
stored packet length.

pad Truncated packets will be padded out so that the packet length matches the IPv4
total length

trunc Truncated packets will have their IPv4 total length field rewritten to match
the actual packet length

del Delete the packet

--fuzz-seed=number
Fuzz 1 in X packets. Edit bytes, length, or emulate packet drop. This option takes
an integer number as its argument. The value of number is constrained to being:
greater than or equal to 0
The default number for this option is:
0

This fuzzing was designed as to test layer 7 protocols such as voip protocols. It
modifies randomly 1 out of X packets (where X = --fuzz-factor) in order for
stateful protocols to cover more of their code. The random fuzzing actions focus
on data start and end because it often is the part of the data application
protocols base their decisions on.

Possible fuzzing actions list:
* drop packet
* reduce packet size
* edit packet Bytes:
* Not all Bytes have the same probability of appearance in real life.
Replace with 0x00, 0xFF, or a random byte with equal likelihood.
* Not all Bytes have the same significance in a packet.
Replace the start, the end, or the middle of the packet with equal likelihood.
* do nothing (7 out of 8 packets)

--fuzz-factor=number
Set the Fuzz 1 in X packet ratio (default 1 in 8 packets). This option must appear
in combination with the following options: fuzz-seed. This option takes an integer
number as its argument. The value of number is constrained to being:
greater than or equal to 1
The default number for this option is:
8

Sets the ratio of for --fuzz-seed option. By default this value is 8, which means 1
in 8 packets are modified by fuzzing. Note that this ratio is based on the random
number generated by the supplied fuzz seed. Therefore by default you cannot expect
that exactly every eighth packet will be modified.

--skipl2broadcast
Skip rewriting broadcast/multicast Layer 2 addresses.

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.

--dlt=string
Override output DLT encapsulation. This option may appear up to 1 times.

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:

enet Ethernet aka DLT_EN10MB

hdlc Cisco HDLC aka DLT_C_HDLC

jnpr_eth Juniper Ethernet DLT_C_JNPR_ETHER

pppserial PPP Serial aka DLT_PPP_SERIAL

user User specified Layer 2 header and DLT type

--enet-dmac=string
Override destination ethernet MAC addresses. This option may appear up to 1 times.

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:
--enet-dmac=00:12:13:14:15:16,00:22:33:44:55:66

--enet-smac=string
Override source ethernet MAC addresses. This option may appear up to 1 times.

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:
--enet-smac=00:12:13:14:15:16,00:22:33:44:55:66

--enet-subsmac=string
Substitute MAC addresses. This option may appear up to 9999 times.

Allows you to rewrite ethernet MAC addresses of packets. It takes comma delimited
pair or MACs address and rewrites all occurrences of the first MAC with the value
of the second MAC. Example:
--enet-subsmac=00:12:13:14:15:16,00:22:33:44:55:66

--enet-mac-seed=number
Randomize MAC addresses. This option may appear up to 1 times. This option must
not appear in combination with any of the following options: enet-smac, enet-dmac,
enet-subsmac. This option takes an integer number as its argument.

Allows you to randomize ethernet MAC addresses of packets, mostly like what --seed
option does for IPv4/IPv6 addresses.

--enet-mac-seed-keep-bytes=number
Randomize MAC addresses. This option may appear up to 1 times. This option must
appear in combination with the following options: enet-mac-seed. This option takes
an integer number as its argument. The value of number is constrained to being:
in the range 1 through 6

Keep some bytes untouched when usinging --enet-mac-seed option.

--enet-vlan=string
Specify ethernet 802.1q VLAN tag mode. This option may appear up to 1 times.

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.

add Adds an 802.1q VLAN header to the existing 802.3 ethernet header. If a VLAN
header already exists, a new VLAN header is added outside of the existing header.

Note that you will be allowed to run this option multiple times to create more than
2 VLAN headers, however those packets will be valid. At most you should have 2 X
802.1q VLAN tags, or outer an 802.1ad and an inner 802.1q VLAN tag.

del Rewrites the existing 802.1q VLAN header as an 802.3 ethernet header

--enet-vlan-tag=number
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 number is
constrained to being:
in the range 0 through 4095

--enet-vlan-cfi=number
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 number is constrained
to being:
in the range 0 through 1

--enet-vlan-pri=number
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 number is constrained
to being:
in the range 0 through 7

--enet-vlan-proto=string
Specify VLAN tag protocol 802.1q or 802.1ad. This option may appear up to 1 times.

Allows you to specify the protocol of the added VLAN tags.

802.1q Specifies that 802.1q VLAN headers are to be added. This is the default.

802.1ad Specifies that 802.1ad Q-in-Q VLAN headers are to be added. To make valid
packets, input packets must already have 802.1q VLAN headers.

--hdlc-control=number
Specify HDLC control value. This option may appear up to 1 times. This option
takes an integer number as its argument.

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.

--hdlc-address=number
Specify HDLC address. This option may appear up to 1 times. This option takes an
integer number as its argument.

The Cisco HDLC header has a 1 byte "address" field which has two valid values:

0x0F Unicast

0xBF Broadcast
You can however specify any single byte value.

--user-dlt=number
Set output file DLT type. This option may appear up to 1 times. This option takes
an integer number as its argument.

Set the DLT value of the output pcap file.

--user-dlink=string
Rewrite Data-Link layer with user specified data. This option may appear up to 2
times.

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:
--user-dlink=01,02,03,04,05,06,00,1A,2B,3C,4D,5E,6F,08,00

-d number, --dbug=number
Enable debugging output. This option may appear up to 1 times. This option takes
an integer number as its argument. The value of number is constrained to being:
in the range 0 through 5
The default number for this option is:
0

If configured with --enable-debug, then you can specify a verbosity level for
debugging output. Higher numbers increase verbosity.

-i string, --infile=string
Input pcap file to be processed. This option may appear up to 1 times.

-o string, --outfile=string
Output pcap file. This option may appear up to 1 times.

-c string, --cachefile=string
Split traffic via tcpprep cache file. This option may appear up to 1 times.

Use tcpprep cache file to split traffic based upon client/server relationships.

-v, --verbose
Print decoded packets via tcpdump to STDOUT. This option may appear up to 1 times.

-A string, --decode=string
Arguments passed to tcpdump decoder. This option may appear up to 1 times. This
option must appear in combination with the following options: verbose.

When enabling verbose mode (-v) you may also specify one or more additional
arguments to pass to tcpdump 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.

--fragroute=string
Parse fragroute configuration file. This option may appear up to 1 times.

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.

--fragdir=string
Which flows to apply fragroute to: c2s, s2c, both. This option may appear up to 1
times. This option must appear in combination with the following options:
cachefile.

Apply the fragroute engine to packets going c2s, s2c or both when using a cache
file.

--skip-soft-errors
Skip writing packets with soft errors. This option may appear up to 1 times.

In some cases, packets can not 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.

-V, --version
Print version information.

-h, --less-help
Display less usage information and exit.

-w, --suppress-warnings
suppress printing warning messages.

-H, --help
Display usage information and exit.

-!, --more-help
Pass the extended usage information through a pager.

--save-opts [=cfgfile]
Save the option state to cfgfile. The default is the last configuration file
listed in the OPTION PRESETS section, below. The command will exit after updating
the config file.

--load-opts=cfgfile, --no-load-opts
Load options from cfgfile. The no-load-opts form will disable the loading of
earlier config/rc/ini files. --no-load-opts is handled early, out of order.

OPTION PRESETS

       Any option that is not marked as not presettable may be preset by loading values from
       configuration ("RC" or ".INI") file(s).  The homerc file is "$$/", unless that is a
       directory.  In that case, the file ".tcprewriterc" is searched for within that directory.

FILES

       See OPTION PRESETS for configuration files.

EXIT STATUS

       One of the following exit values will be returned:

       0  (EXIT_SUCCESS)
              Successful program execution.

       1  (EXIT_FAILURE)
              The operation failed or the command syntax was not valid.

       66  (EX_NOINPUT)
              A specified configuration file could not be loaded.

       70  (EX_SOFTWARE)
              libopts had an internal operational error.  Please report it to autogen-
              users@lists.sourceforge.net.  Thank you.

AUTHORS

       Copyright 2013-2024 Fred Klassen - AppNeta Copyright 2000-2012 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.appneta.com/

COPYRIGHT

       Copyright (C) 2000-2024 Aaron Turner and Fred Klassen all rights reserved.  This program
       is released under the terms of the GNU General Public License, version 3 or later.

BUGS

       Please send bug reports to: tcpreplay-users@lists.sourceforge.net

NOTES

       This manual page was AutoGen-erated from the tcprewrite option definitions.