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 [ -a ] [ -d ] [ -D ] [ -e <l3pid> ] [ -h ] [ -i <proto> ]
10 [ -l <typenum> ] [ -n ] [ -N <intf-name> ] [ -m <max-packet> ]
11 [ -o hex|oct|dec ] [ -q ] [ -s <srcport>,<destport>,<tag> ]
12 [ -S <srcport>,<destport>,<ppi> ] [ -t <timefmt> ]
13 [ -T <srcport>,<destport> ] [ -u <srcport>,<destport> ] [ -v ]
14 [ -4 <srcip>,<destip> ] [ -6 <srcip>,<destip> ] <infile>|- <outfile>|-
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17 Text2pcap is a program that reads in an ASCII hex dump and writes the
18 data described into a pcap or pcapng capture file. text2pcap can read
19 hexdumps with multiple packets in them, and build a capture file of
20 multiple packets. text2pcap is also capable of generating dummy
21 Ethernet, IP and UDP, TCP, or SCTP headers, in order to build fully
22 processable packet dumps from hexdumps of application-level data only.
23 Text2pcap understands a hexdump of the form generated by od -Ax -tx1
25 -v. In other words, each byte is individually displayed, with spaces
26 separating the bytes from each other. Each line begins with an offset
27 describing the position in the packet, each new packet starts with an
28 offset of 0 and there is a space separating the offset from the
29 following bytes. The offset is a hex number (can also be octal or
30 decimal - see -o), of more than two hex digits.
31 Here is a sample dump that text2pcap can recognize:
33 000000 00 0e b6 00 00 02 00 0e b6 00 00 01 08 00 45 00
35 000010 00 28 00 00 00 00 ff 01 37 d1 c0 00 02 01 c0 00
36 000020 02 02 08 00 a6 2f 00 01 00 01 48 65 6c 6c 6f 20
37 000030 57 6f 72 6c 64 21
38 000036
39 Note the last byte must either be followed by the expected next offset
41 value as in the example above or a space or a line-end character(s).
42 There is no limit on the width or number of bytes per line. Also the
44 text dump at the end of the line is ignored. Bytes/hex numbers can be
45 uppercase or lowercase. Any text before the offset is ignored,
46 including email forwarding characters '>'. Any lines of text between
47 the bytestring lines is ignored. The offsets are used to track the
48 bytes, so offsets must be correct. Any line which has only bytes
49 without a leading offset is ignored. An offset is recognized as being a
50 hex number longer than two characters. Any text after the bytes is
51 ignored (e.g. the character dump). Any hex numbers in this text are
52 also ignored. An offset of zero is indicative of starting a new packet,
53 so a single text file with a series of hexdumps can be converted into a
54 packet capture with multiple packets. Packets may be preceded by a
55 timestamp. These are interpreted according to the format given on the
56 command line (see -t). If not, the first packet is timestamped with the
57 current time the conversion takes place. Multiple packets are written
58 with timestamps differing by one microsecond each. In general, short
59 of these restrictions, text2pcap is pretty liberal about reading in
60 hexdumps and has been tested with a variety of mangled outputs
61 (including being forwarded through email multiple times, with limited
62 line wrap etc.)
63 There are a couple of other special features to note. Any line where
65 the first non-whitespace character is '#' will be ignored as a comment.
66 Any line beginning with #TEXT2PCAP is a directive and options can be
67 inserted after this command to be processed by text2pcap. Currently
68 there are no directives implemented; in the future, these may be used
69 to give more fine grained control on the dump and the way it should be
70 processed e.g. timestamps, encapsulation type etc.
71 Text2pcap also allows the user to read in dumps of application-level
73 data, by inserting dummy L2, L3 and L4 headers before each packet. The
74 user can elect to insert Ethernet headers, Ethernet and IP, or
75 Ethernet, IP and UDP/TCP/SCTP headers before each packet. This allows
76 Wireshark or any other full-packet decoder to handle these dumps.
77
79 -a Enables ASCII text dump identification. It allows one to identify
80 the start of the ASCII text dump and not include it in the packet
81 even if it looks like HEX.
82 NOTE: Do not enable it if the input file does not contain the ASCII
84 text dump.
85 -d Displays debugging information during the process. Can be used
87 multiple times to generate more debugging information.
88 -D The text before the packet starts either with an I or O indicating
90 that the packet is inbound or outbound. This is used when
91 generating dummy headers. The indication is only stored if the
92 output format is pcapng.
93 -e <l3pid>
95 Include a dummy Ethernet header before each packet. Specify the
96 L3PID for the Ethernet header in hex. Use this option if your dump
97 has Layer 3 header and payload (e.g. IP header), but no Layer 2
98 encapsulation. Example: -e 0x806 to specify an ARP packet.
99 For IP packets, instead of generating a fake Ethernet header you
101 can also use -l 101 to indicate a raw IP packet to Wireshark. Note
102 that -l 101 does not work for any non-IP Layer 3 packet (e.g. ARP),
103 whereas generating a dummy Ethernet header with -e works for any
104 sort of L3 packet.
105 -h Displays a help message.
107 -i <proto>
109 Include dummy IP headers before each packet. Specify the IP
110 protocol for the packet in decimal. Use this option if your dump is
111 the payload of an IP packet (i.e. has complete L4 information) but
112 does not have an IP header with each packet. Note that an
113 appropriate Ethernet header is automatically included with each
114 packet as well. Example: -i 46 to specify an RSVP packet (IP
115 protocol 46). See
116 <https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml>
117 for the complete list of assigned internet protocol numbers.
118 -l Specify the link-layer header type of this packet. Default is
120 Ethernet (1). See <https://www.tcpdump.org/linktypes.html> for the
121 complete list of possible encapsulations. Note that this option
122 should be used if your dump is a complete hex dump of an
123 encapsulated packet and you wish to specify the exact type of
124 encapsulation. Example: -l 7 for ARCNet packets encapsulated BSD-
125 style.
126 -m <max-packet>
128 Set the maximum packet length, default is 262144. Useful for
129 testing various packet boundaries when only an application level
130 datastream is available. Example:
131 od -Ax -tx1 -v stream | text2pcap -m1460 -T1234,1234 - stream.pcap
133 will convert from plain datastream format to a sequence of Ethernet
135 TCP packets.
136 -n Write the file in pcapng format rather than pcap format.
138 -N <intf-name>
140 Specify a name for the interface included when writing a pcapng
141 format file. By default no name is defined.
142 -o hex|oct|dec
144 Specify the radix for the offsets (hex, octal or decimal). Defaults
145 to hex. This corresponds to the "-A" option for od.
146 -q Be completely quiet during the process.
148 -s <srcport>,<destport>,<tag>
150 Include dummy SCTP headers before each packet. Specify, in
151 decimal, the source and destination SCTP ports, and verification
152 tag, for the packet. Use this option if your dump is the SCTP
153 payload of a packet but does not include any SCTP, IP or Ethernet
154 headers. Note that appropriate Ethernet and IP headers are
155 automatically also included with each packet. A CRC32C checksum
156 will be put into the SCTP header.
157 -S <srcport>,<destport>,<ppi>
159 Include dummy SCTP headers before each packet. Specify, in
160 decimal, the source and destination SCTP ports, and a verification
161 tag of 0, for the packet, and prepend a dummy SCTP DATA chunk
162 header with a payload protocol identifier if ppi. Use this option
163 if your dump is the SCTP payload of a packet but does not include
164 any SCTP, IP or Ethernet headers. Note that appropriate Ethernet
165 and IP headers are automatically included with each packet. A
166 CRC32C checksum will be put into the SCTP header.
167 -t <timefmt>
169 Treats the text before the packet as a date/time code; timefmt is a
170 format string of the sort supported by strptime(3). Example: The
171 time "10:15:14.5476" has the format code "%H:%M:%S."
172 NOTE: The subsecond component delimiter must be specified (.) but
174 no pattern is required; the remaining number is assumed to be
175 fractions of a second.
176 NOTE: Date/time fields from the current date/time are used as the
178 default for unspecified fields.
179 -T <srcport>,<destport>
181 Include dummy TCP headers before each packet. Specify the source
182 and destination TCP ports for the packet in decimal. Use this
183 option if your dump is the TCP payload of a packet but does not
184 include any TCP, IP or Ethernet headers. Note that appropriate
185 Ethernet and IP headers are automatically also included with each
186 packet. Sequence numbers will start at 0.
187 -u <srcport>,<destport>
189 Include dummy UDP headers before each packet. Specify the source
190 and destination UDP ports for the packet in decimal. Use this
191 option if your dump is the UDP payload of a packet but does not
192 include any UDP, IP or Ethernet headers. Note that appropriate
193 Ethernet and IP headers are automatically also included with each
194 packet. Example: -u1000,69 to make the packets look like TFTP/UDP
195 packets.
196 -v Print the version and exit.
198 -4 <srcip>,<destip>
200 Prepend dummy IP header with specified IPv4 dest and source
201 address. This option should be accompanied by one of the following
202 options: -i, -s, -S, -T, -u Use this option to apply "custom" IP
203 addresses. Example: -4 10.0.0.1,10.0.0.2 to use 10.0.0.1 and
204 10.0.0.2 for all IP packets.
205 -6 <srcip>,<destip>
207 Prepend dummy IP header with specified IPv6 dest and source
208 address. This option should be accompanied by one of the following
209 options: -i, -s, -S, -T, -u Use this option to apply "custom" IP
210 addresses. Example: -6
211 fe80::202:b3ff:fe1e:8329,2001:0db8:85a3::8a2e:0370:7334 to use
212 fe80::202:b3ff:fe1e:8329 and 2001:0db8:85a3::8a2e:0370:7334 for all
213 IP packets.
214
216 od(1), pcap(3), wireshark(1), tshark(1), dumpcap(1), mergecap(1),
217 editcap(1), strptime(3), pcap-filter(7) or tcpdump(8)
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220 Text2pcap is part of the Wireshark distribution. The latest version of
221 Wireshark can be found at <https://www.wireshark.org>.
222
224 Ashok Narayanan <ashokn[AT]cisco.com>
2253.4.5 2021-05-27 TEXT2PCAP(1)