TEXT2PCAP(1) The Ethereal Network Analyzer TEXT2PCAP(1)NAMEtext2pcap - Generate a capture file from an ASCII hexdump of packets
SYNOPSYStext2pcap [ -d ] [ -q ] [ -o hex⎪oct ] [ -l typenum ] [ -e l3pid ]
[ -i proto ] [ -u srcport,destport ] [ -s srcport,destport,tag ]
[ -S srcport,destport,tag ] [ -t timefmt ] infile outfile
DESCRIPTION
Text2pcap is a program that reads in an ASCII hex dump and writes the
data described into a libpcap-style capture file. text2pcap can read
hexdumps with multiple packets in them, and build a capture file of
multiple packets. text2pcap is also capable of generating dummy
Ethernet, IP and UDP headers, in order to build fully processable
packet dumps from hexdumps of application-level data only.
Text2pcap understands a hexdump of the form generated by od -t x1. In
other words, each byte is individually displayed and surrounded with a
space. Each line begins with an offset describing the position in the
file. The offset is a hex number (can also be octal - see -o), of more
than two hex digits. Here is a sample dump that text2pcap can
recognize:
000000 00 e0 1e a7 05 6f 00 10 ........
000008 5a a0 b9 12 08 00 46 00 ........
000010 03 68 00 00 00 00 0a 2e ........
000018 ee 33 0f 19 08 7f 0f 19 ........
000020 03 80 94 04 00 00 10 01 ........
000028 16 a2 0a 00 03 50 00 0c ........
000030 01 01 0f 19 03 80 11 01 ........
There is no limit on the width or number of bytes per line. Also the
text dump at the end of the line is ignored. Bytes/hex numbers can be
uppercase or lowercase. Any text before the offset is ignored,
including email forwarding characters '>'. Any lines of text between
the bytestring lines is ignored. The offsets are used to track the
bytes, so offsets must be correct. Any line which has only bytes
without a leading offset is ignored. An offset is recognized as being a
hex number longer than two characters. Any text after the bytes is
ignored (e.g. the character dump). Any hex numbers in this text are
also ignored. An offset of zero is indicative of starting a new packet,
so a single text file with a series of hexdumps can be converted into a
packet capture with multiple packets. Multiple packets are read in with
timestamps differing by one second each. In general, short of these
restrictions, text2pcap is pretty liberal about reading in hexdumps and
has been tested with a variety of mangled outputs (including being
forwarded through email multiple times, with limited line wrap etc.)
There are a couple of other special features to note. Any line where
the first non-whitespace character is '#' will be ignored as a comment.
Any line beginning with #TEXT2PCAP is a directive and options can be
inserted after this command to be processed by text2pcap. Currently
there are no directives implemented; in the future, these may be used
to give more fine grained control on the dump and the way it should be
processed e.g. timestamps, encapsulation type etc.
Text2pcap also allows the user to read in dumps of application-level
data, by inserting dummy L2, L3 and L4 headers before each packet. The
user can elect to insert Ethernet headers, Ethernet and IP, or
Ethernet, IP and UDP headers before each packet. This allows Ethereal
or any other full-packet decoder to handle these dumps.
OPTIONS-d Displays debugging information during the process. Can be used
multiple times to generate more debugging information.
-q Be completely quiet during the process.
-o hex⎪oct
Specify the radix for the offsets (hex or octal). Defaults to hex.
This corresponds to the -A option for od.
-l Specify the link-layer type of this packet. Default is Ethernet
(1). See net/bpf.h for the complete list of possible
encapsulations. Note that this option should be used if your dump
is a complete hex dump of an encapsulated packet and you wish to
specify the exact type of encapsulation. Example: -l 7 for ARCNet
packets.
-e l3pid
Include a dummy Ethernet header before each packet. Specify the
L3PID for the Ethernet header in hex. Use this option if your dump
has Layer 3 header and payload (e.g. IP header), but no Layer 2
encapsulation. Example: -e 0x806 to specify an ARP packet.
For IP packets, instead of generating a fake Ethernet header you
can also use -l 12 to indicate a raw IP packet to Ethereal. Note
that -l 12 does not work for any non-IP Layer 3 packet (e.g. ARP),
whereas generating a dummy Ethernet header with -e works for any
sort of L3 packet.
-i proto
Include dummy IP headers before each packet. Specify the IP
protocol for the packet in decimal. Use this option if your dump is
the payload of an IP packet (i.e. has complete L4 information) but
does not have an IP header. Note that this automatically includes
an appropriate Ethernet header as well. Example: -i 46 to specify
an RSVP packet (IP protocol 46).
-u srcport,destport
Include dummy UDP headers before each packet. Specify the source
and destination UDP ports for the packet in decimal. Use this
option if your dump is the UDP payload of a packet but does not
include any UDP, IP or Ethernet headers. Note that this
automatically includes appropriate Ethernet and IP headers with
each packet. Example: -u 1000,69 to make the packets look like
TFTP/UDP packets.
-s srcport,destport,tag
Include dummy SCTP headers before each packet. Specify the source
and destination SCTP ports, and verification tag, for the packet in
decimal. Use this option if your dump is the SCTP payload of a
packet but does not include any SCTP, IP or Ethernet headers. Note
that this automatically includes appropriate Ethernet and IP
headers with each packet. A CRC32C checksum will be put into the
SCTP header.
-S srcport,destport,tag
Like -s, but it also includes the DATA chunk header, for input
files that contain only the SCTP payload.
-t timefmt
Treats the text before the packet as a date/time code; timefmt is a
format string of the sort supported by strptime(3). Example: The
time "10:15:14.5476" has the format code "%H:%M:%S."
NOTE: The subsecond component delimiter must be specified (.) but
no pattern is required; the remaining number is assumed to be
fractions of a second.
SEE ALSOtcpdump(8), pcap(3), ethereal(1), editcap(1), strptime(3).
NOTES
Text2pcap is part of the Ethereal distribution. The latest version of
Ethereal can be found at http://www.ethereal.com.
AUTHORS
Ashok Narayanan <ashokn@cisco.com>
3rd Berkeley Distribution 0.9.3 TEXT2PCAP(1)
