1TEXT2PCAP(1) The Wireshark Network Analyzer TEXT2PCAP(1)
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6 text2pcap - Generate a capture file from an ASCII hexdump of packets
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9 text2pcap [ -h ] [ -d ] [ -q ] [ -o hex⎪oct⎪dec ] [ -l <typenum> ]
10 [ -e <l3pid> ] [ -i <proto> ] [ -m <max-packet> ] [ -u <srcport>,<dest‐
11 port> ] [ -T <srcport>,<destport> ] [ -s <srcport>,<destport>,<tag> ]
12 [ -S <srcport>,<destport>,<ppi> ] [ -t <timefmt> ] <infile>⎪- <out‐
13 file>⎪-
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16 Text2pcap is a program that reads in an ASCII hex dump and writes the
17 data described into a libpcap capture file. text2pcap can read hex‐
18 dumps with multiple packets in them, and build a capture file of multi‐
19 ple packets. text2pcap is also capable of generating dummy Ethernet,
20 IP and UDP, TCP, or SCTP headers, in order to build fully processable
21 packet dumps from hexdumps of application-level data only.
22 Text2pcap understands a hexdump of the form generated by od -Ax -tx1.
24 In other words, each byte is individually displayed and surrounded with
25 a space. Each line begins with an offset describing the position in the
26 file. The offset is a hex number (can also be octal or decimal - see
27 -o), of more than two hex digits. Here is a sample dump that text2pcap
28 can recognize:
29 000000 00 e0 1e a7 05 6f 00 10 ........
31 000008 5a a0 b9 12 08 00 46 00 ........
32 000010 03 68 00 00 00 00 0a 2e ........
33 000018 ee 33 0f 19 08 7f 0f 19 ........
34 000020 03 80 94 04 00 00 10 01 ........
35 000028 16 a2 0a 00 03 50 00 0c ........
36 000030 01 01 0f 19 03 80 11 01 ........
37 There is no limit on the width or number of bytes per line. Also the
39 text dump at the end of the line is ignored. Bytes/hex numbers can be
40 uppercase or lowercase. Any text before the offset is ignored, includ‐
41 ing email forwarding characters '>'. Any lines of text between the
42 bytestring lines is ignored. The offsets are used to track the bytes,
43 so offsets must be correct. Any line which has only bytes without a
44 leading offset is ignored. An offset is recognized as being a hex num‐
45 ber longer than two characters. Any text after the bytes is ignored
46 (e.g. the character dump). Any hex numbers in this text are also
47 ignored. An offset of zero is indicative of starting a new packet, so a
48 single text file with a series of hexdumps can be converted into a
49 packet capture with multiple packets. Multiple packets are read in with
50 timestamps differing by one second each. In general, short of these
51 restrictions, text2pcap is pretty liberal about reading in hexdumps and
52 has been tested with a variety of mangled outputs (including being for‐
53 warded through email multiple times, with limited line wrap etc.)
54 There are a couple of other special features to note. Any line where
56 the first non-whitespace character is '#' will be ignored as a comment.
57 Any line beginning with #TEXT2PCAP is a directive and options can be
58 inserted after this command to be processed by text2pcap. Currently
59 there are no directives implemented; in the future, these may be used
60 to give more fine grained control on the dump and the way it should be
61 processed e.g. timestamps, encapsulation type etc.
62 Text2pcap also allows the user to read in dumps of application-level
64 data, by inserting dummy L2, L3 and L4 headers before each packet. The
65 user can elect to insert Ethernet headers, Ethernet and IP, or Ether‐
66 net, IP and UDP/TCP headers before each packet. This allows Wireshark
67 or any other full-packet decoder to handle these dumps.
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70 -h Displays a help message.
71 -d Displays debugging information during the process. Can be used mul‐
73 tiple times to generate more debugging information.
74 -q Be completely quiet during the process.
76 -o hex⎪oct⎪dec
78 Specify the radix for the offsets (hex, octal or decimal). Defaults
79 to hex. This corresponds to the "-A" option for od.
80 -l Specify the link-layer type of this packet. Default is Ethernet
82 (1). See net/bpf.h for the complete list of possible encapsula‐
83 tions. Note that this option should be used if your dump is a com‐
84 plete hex dump of an encapsulated packet and you wish to specify
85 the exact type of encapsulation. Example: -l 7 for ARCNet packets.
86 -e <l3pid>
88 Include a dummy Ethernet header before each packet. Specify the
89 L3PID for the Ethernet header in hex. Use this option if your dump
90 has Layer 3 header and payload (e.g. IP header), but no Layer 2
91 encapsulation. Example: -e 0x806 to specify an ARP packet.
92 For IP packets, instead of generating a fake Ethernet header you
94 can also use -l 12 to indicate a raw IP packet to Wireshark. Note
95 that -l 12 does not work for any non-IP Layer 3 packet (e.g. ARP),
96 whereas generating a dummy Ethernet header with -e works for any
97 sort of L3 packet.
98 -i <proto>
100 Include dummy IP headers before each packet. Specify the IP proto‐
101 col for the packet in decimal. Use this option if your dump is the
102 payload of an IP packet (i.e. has complete L4 information) but does
103 not have an IP header. Note that this automatically includes an
104 appropriate Ethernet header as well. Example: -i 46 to specify an
105 RSVP packet (IP protocol 46).
106 -m <max-packet>
108 Set the maximum packet length, default is 64000. Useful for test‐
109 ing various packet boundaries when only an application level datas‐
110 tream is available. Example:
111 od -Ax -tx1 stream ⎪ text2pcap -m1460 -T1234,1234 - stream.pcap
113 will convert from plain datastream format to a sequence of Ethernet
115 TCP packets.
116 -u <srcport>,<destport>
118 Include dummy UDP headers before each packet. Specify the source
119 and destination UDP ports for the packet in decimal. Use this
120 option if your dump is the UDP payload of a packet but does not
121 include any UDP, IP or Ethernet headers. Note that this automati‐
122 cally includes appropriate Ethernet and IP headers with each
123 packet. Example: -u 1000,69 to make the packets look like TFTP/UDP
124 packets.
125 -T <srcport>,<destport>
127 Include dummy TCP headers before each packet. Specify the source
128 and destination TCP ports for the packet in decimal. Use this
129 option if your dump is the TCP payload of a packet but does not
130 include any TCP, IP or Ethernet headers. Note that this automati‐
131 cally includes appropriate Ethernet and IP headers with each
132 packet. Sequence numbers will start a 0.
133 -s <srcport>,<destport>,<tag>
135 Include dummy SCTP headers before each packet. Specify, in deci‐
136 mal, the source and destination SCTP ports, and verification tag,
137 for the packet. Use this option if your dump is the SCTP payload
138 of a packet but does not include any SCTP, IP or Ethernet headers.
139 Note that this automatically includes appropriate Ethernet and IP
140 headers with each packet. A CRC32C checksum will be put into the
141 SCTP header.
142 -S <srcport>,<destport>,<ppi>
144 Include dummy SCTP headers before each packet. Specify, in deci‐
145 mal, the source and destination SCTP ports, and a verification tag
146 of 0, for the packet, and prepend a dummy SCTP DATA chunk header
147 with a payload protocol identifier if ppi. Use this option if your
148 dump is the SCTP payload of a packet but does not include any SCTP,
149 IP or Ethernet headers. Note that this automatically includes
150 appropriate Ethernet and IP headers with each packet. A CRC32C
151 checksum will be put into the SCTP header.
152 -t <timefmt>
154 Treats the text before the packet as a date/time code; timefmt is a
155 format string of the sort supported by strptime(3). Example: The
156 time "10:15:14.5476" has the format code "%H:%M:%S."
157 NOTE: The subsecond component delimiter must be specified (.) but
159 no pattern is required; the remaining number is assumed to be frac‐
160 tions of a second.
161 NOTE: Date/time fields from the current date/time are used as the
163 default for unspecified fields.
164
166 od(1), tcpdump(8), pcap(3), wireshark(1), tshark(1), dumpcap(1), merge‐
167 cap(1), editcap(1), strptime(3).
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170 Text2pcap is part of the Wireshark distribution. The latest version of
171 Wireshark can be found at <http://www.wireshark.org>.
172
174 Ashok Narayanan <ashokn[AT]cisco.com>
1751.0.0 2008-03-29 TEXT2PCAP(1)