1TEXT2PCAP(1) The Wireshark Network Analyzer TEXT2PCAP(1)
2
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 ] [ -m <max-packet> ] [ -o hex|oct|dec ] [ -q ]
11 [ -s <srcport>,<destport>,<tag> ] [ -S <srcport>,<destport>,<ppi> ]
12 [ -t <timefmt> ] [ -T <srcport>,<destport> ]
13 [ -u <srcport>,<destport> ] [ -v ] <infile>|- <outfile>|-
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16 Text2pcap is a program that reads in an ASCII hex dump and writes the
17 data described into a pcap capture file. text2pcap can read hexdumps
18 with multiple packets in them, and build a capture file of multiple
19 packets. text2pcap is also capable of generating dummy Ethernet, IP
20 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 -v. In other words, each byte is individually displayed, with spaces
25 separating the bytes from each other. Each line begins with an offset
26 describing the position in the packet, each new packet starts with an
27 offset of 0 and there is a space separating the offset from the
28 following bytes. The offset is a hex number (can also be octal or
29 decimal - see -o), of more than two hex digits.
30 Here is a sample dump that text2pcap can recognize:
32 000000 00 0e b6 00 00 02 00 0e b6 00 00 01 08 00 45 00
34 000010 00 28 00 00 00 00 ff 01 37 d1 c0 00 02 01 c0 00
35 000020 02 02 08 00 a6 2f 00 01 00 01 48 65 6c 6c 6f 20
36 000030 57 6f 72 6c 64 21
37 000036
38 Note the last byte must either be followed by the expected next offset
40 value as in the example above or a space or a line-end character(s).
41 There is no limit on the width or number of bytes per line. Also the
43 text dump at the end of the line is ignored. Bytes/hex numbers can be
44 uppercase or lowercase. Any text before the offset is ignored,
45 including email forwarding characters '>'. Any lines of text between
46 the bytestring lines is ignored. The offsets are used to track the
47 bytes, so offsets must be correct. Any line which has only bytes
48 without a leading offset is ignored. An offset is recognized as being a
49 hex number longer than two characters. Any text after the bytes is
50 ignored (e.g. the character dump). Any hex numbers in this text are
51 also ignored. An offset of zero is indicative of starting a new packet,
52 so a single text file with a series of hexdumps can be converted into a
53 packet capture with multiple packets. Packets may be preceded by a
54 timestamp. These are interpreted according to the format given on the
55 command line (see -t). If not, the first packet is timestamped with the
56 current time the conversion takes place. Multiple packets are written
57 with timestamps differing by one microsecond each. In general, short
58 of these restrictions, text2pcap is pretty liberal about reading in
59 hexdumps and has been tested with a variety of mangled outputs
60 (including being forwarded through email multiple times, with limited
61 line wrap etc.)
62 There are a couple of other special features to note. Any line where
64 the first non-whitespace character is '#' will be ignored as a comment.
65 Any line beginning with #TEXT2PCAP is a directive and options can be
66 inserted after this command to be processed by text2pcap. Currently
67 there are no directives implemented; in the future, these may be used
68 to give more fine grained control on the dump and the way it should be
69 processed e.g. timestamps, encapsulation type etc.
70 Text2pcap also allows the user to read in dumps of application-level
72 data, by inserting dummy L2, L3 and L4 headers before each packet. The
73 user can elect to insert Ethernet headers, Ethernet and IP, or
74 Ethernet, IP and UDP/TCP/SCTP headers before each packet. This allows
75 Wireshark or any other full-packet decoder to handle these dumps.
76
78 -a Enables ASCII text dump identification. It allows one to identify
79 the start of the ASCII text dump and not include it in the packet
80 even if it looks like HEX.
81 NOTE: Do not enable it if the input file does not contain the ASCII
83 text dump.
84 -d Displays debugging information during the process. Can be used
86 multiple times to generate more debugging information.
87 -D The text before the packet starts either with an I or O indicating
89 that the packet is inbound or outbound. This is only stored if the
90 output format is pcapng.
91 -e <l3pid>
93 Include a dummy Ethernet header before each packet. Specify the
94 L3PID for the Ethernet header in hex. Use this option if your dump
95 has Layer 3 header and payload (e.g. IP header), but no Layer 2
96 encapsulation. Example: -e 0x806 to specify an ARP packet.
97 For IP packets, instead of generating a fake Ethernet header you
99 can also use -l 101 to indicate a raw IP packet to Wireshark. Note
100 that -l 101 does not work for any non-IP Layer 3 packet (e.g. ARP),
101 whereas generating a dummy Ethernet header with -e works for any
102 sort of L3 packet.
103 -h Displays a help message.
105 -i <proto>
107 Include dummy IP headers before each packet. Specify the IP
108 protocol for the packet in decimal. Use this option if your dump is
109 the payload of an IP packet (i.e. has complete L4 information) but
110 does not have an IP header with each packet. Note that an
111 appropriate Ethernet header is automatically included with each
112 packet as well. Example: -i 46 to specify an RSVP packet (IP
113 protocol 46). See
114 <http://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml>
115 for the complete list of assigned internet protocol numbers.
116 -l Specify the link-layer header type of this packet. Default is
118 Ethernet (1). See <http://www.tcpdump.org/linktypes.html> for the
119 complete list of possible encapsulations. Note that this option
120 should be used if your dump is a complete hex dump of an
121 encapsulated packet and you wish to specify the exact type of
122 encapsulation. Example: -l 7 for ARCNet packets encapsulated BSD-
123 style.
124 -m <max-packet>
126 Set the maximum packet length, default is 262144. Useful for
127 testing various packet boundaries when only an application level
128 datastream is available. Example:
129 od -Ax -tx1 -v stream | text2pcap -m1460 -T1234,1234 - stream.pcap
131 will convert from plain datastream format to a sequence of Ethernet
133 TCP packets.
134 -n Write the file in pcapng format rather than pcap format.
136 -o hex|oct|dec
138 Specify the radix for the offsets (hex, octal or decimal). Defaults
139 to hex. This corresponds to the "-A" option for od.
140 -q Be completely quiet during the process.
142 -s <srcport>,<destport>,<tag>
144 Include dummy SCTP headers before each packet. Specify, in
145 decimal, the source and destination SCTP ports, and verification
146 tag, for the packet. Use this option if your dump is the SCTP
147 payload of a packet but does not include any SCTP, IP or Ethernet
148 headers. Note that appropriate Ethernet and IP headers are
149 automatically also included with each packet. A CRC32C checksum
150 will be put into the SCTP header.
151 -S <srcport>,<destport>,<ppi>
153 Include dummy SCTP headers before each packet. Specify, in
154 decimal, the source and destination SCTP ports, and a verification
155 tag of 0, for the packet, and prepend a dummy SCTP DATA chunk
156 header with a payload protocol identifier if ppi. Use this option
157 if your dump is the SCTP payload of a packet but does not include
158 any SCTP, IP or Ethernet headers. Note that appropriate Ethernet
159 and IP headers are automatically included with each packet. A
160 CRC32C checksum will be put into the SCTP header.
161 -t <timefmt>
163 Treats the text before the packet as a date/time code; timefmt is a
164 format string of the sort supported by strptime(3). Example: The
165 time "10:15:14.5476" has the format code "%H:%M:%S."
166 NOTE: The subsecond component delimiter must be specified (.) but
168 no pattern is required; the remaining number is assumed to be
169 fractions of a second.
170 NOTE: Date/time fields from the current date/time are used as the
172 default for unspecified fields.
173 -T <srcport>,<destport>
175 Include dummy TCP headers before each packet. Specify the source
176 and destination TCP ports for the packet in decimal. Use this
177 option if your dump is the TCP payload of a packet but does not
178 include any TCP, IP or Ethernet headers. Note that appropriate
179 Ethernet and IP headers are automatically also included with each
180 packet. Sequence numbers will start at 0.
181 -u <srcport>,<destport>
183 Include dummy UDP headers before each packet. Specify the source
184 and destination UDP ports for the packet in decimal. Use this
185 option if your dump is the UDP payload of a packet but does not
186 include any UDP, IP or Ethernet headers. Note that appropriate
187 Ethernet and IP headers are automatically also included with each
188 packet. Example: -u1000,69 to make the packets look like TFTP/UDP
189 packets.
190 -v Print the version and exit.
192 -4 <srcip>,<destip>
194 Prepend dummy IP header with specified IPv4 dest and source
195 address. This option should be accompanied by one of the following
196 options: -i, -s, -S, -T, -u Use this option to apply "custom" IP
197 addresses. Example: -4 10.0.0.1,10.0.0.2 to use 10.0.0.1 and
198 10.0.0.2 for all IP packets.
199 -6 <srcip>,<destip>
201 Prepend dummy IP header with specified IPv6 dest and source
202 address. This option should be accompanied by one of the following
203 options: -i, -s, -S, -T, -u Use this option to apply "custom" IP
204 addresses. Example: -6 fe80:0:0:0:202:b3ff:fe1e:8329,
205 2001:0db8:85a3:0000:0000:8a2e:0370:7334 to use
206 fe80:0:0:0:202:b3ff:fe1e:8329 and
207 2001:0db8:85a3:0000:0000:8a2e:0370:7334 for all IP packets.
208
210 od(1), pcap(3), wireshark(1), tshark(1), dumpcap(1), mergecap(1),
211 editcap(1), strptime(3), pcap-filter(7) or tcpdump(8)
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214 Text2pcap is part of the Wireshark distribution. The latest version of
215 Wireshark can be found at <https://www.wireshark.org>.
216
218 Ashok Narayanan <ashokn[AT]cisco.com>
2192.6.2 2018-07-18 TEXT2PCAP(1)