pcapfix v1.1.7 README
*********************

Pcapfix is a tool to repair your damaged or corrupted pcap and pcapng files.
It is written in C and released under the GNU General Public License.

To fix your pcap files the tool first checks for an intact pcap global header
and repairs it if there are some corrupted bytes. It there seems to be no
global header at all, pcapfix adds a self-created one at the beginning of the
file. In a second step the tool tries to find pcap packet headers inside the
file, below the global header. It checks if the values are correct (or seem
to be correct) and tries to repair a packet if there is something wrong. 

To fix your pcapng files the tool loops through all packet headers that can
be found in the file. It checks for mandatory Section Header Block and
Interface Description Block and creates them if missing. Pcapfix checks for
correct block sizes and valid option fields. If something is wrong, invalid
fields are repaired (if possible) or skipped and adjusted to finally get a
proper pcapng file.

Please send any further wishes, feature requests or problems in compiling
and execution to ruport@f00l.de. Additionally You may send me pcap/pcapng
files that could not be repaired too in order to improve pcapfix and get
your file repaired.

For further information visit the pcapfix homepage at http://f00l.de/pcapfix/.

USAGE
=====

./pcapfix [OPTIONS] filename
OPTIONS:        -d        , --deep-scan 	  	Deep Scan (default = 0) (pcap only!)
		-s        , --soft-mode			Soft mode (packet detection)
                -n        , --pcapng 	  		Force File Format to PCAPNG
		-o <file> , --outfile <file>		Set output file name
                -t <nr>	  , --data-link-type <nr>	Data Link Type (default = 1)
                -v        , --verbose 	  		Verbose output (default = 0)

Output file name
................
If you want to perform the reparation process on the input file without creating a
separate output file - e.g. in case you are out of space, you can use the -o option
and give the same name as the input file.

WARNING: This process is DANGEROUS and may destroy your data. You should only use
this option if you know what you are doing and accept the risk of losing the input
file.

Deep Scan Option
................

In classic pcap files, pcapfix will only scan the first 65536 bytes (maximum
packet length) for a proper first packet. If you want to force packet detection
even above this limit (e.g. because your file has been heavily destroyed) you
can use the deep scan option (-d).

This option is not necessary for pcapng files because the whole file is arranged
in blocks that are 'unlimited' by default. In result pcapfix will always scan
the whole pcapng file for further blocks.


Soft Mode
.........

There are programs that breach some pcap conventions when writing files.
Ignoring those rules do not break the pcap file but they make it difficult for
pcapfix to identify the packets in case of broken files.

By default pcapfix uses hard mode. If you encounter problems when repairing
files, try to switch to soft mode (-s). Pcapfix will then try to find the
packets in a more tolerant way.


PCAPNG Format
.............

Pcapfix will try to identify the file format to repair (pcap / pcapng) before
doing any further checks. If the header itself is corrupted, it will assume the
format to be classic pcap. To change this behaviour you can force the tool to
do a pcapng-repair by supplying -n (--pcapng) option.


Verbosity
.........

You can use multiple -v options to increase verbosity.
An verbosity of 2 will result in very much output data during package search.


ASCII-mode transfered Files (FTP)
.................................

Pcapfix is able to repair classic pcap files that have been transfered in
ascii-mode via FTP. In those files a proper pcap structure will be created
only to make them readable by wireshark etc. The data inside the packets
(and some pcap headers) might still be corrupted. To repair those packets
a deeper look inside the packet structure (e.g. checksum) will be necessary.


Data Link Types
...............

You can make pcapfix change / select your data link type by supplying -t option.
Although you may select a data link type number between 0 and 255, only the
following types are assigned: If the data link type field is corrupt, pcapfix
will select LINKTYPE_ETHERNET by default.

See http://www.tcpdump.org/linktypes.html for futher information.

NUMBER	LINK_TYPE

0	LINKTYPE_NULL
1	LINKTYPE_ETHERNET
6	LINKTYPE_TOKEN_RING
7	LINKTYPE_ARCNET_BSD
8	LINKTYPE_SLIP
9	LINKTYPE_PPP
10	LINKTYPE_FDDI
50	LINKTYPE_PPP_HDLC
51	LINKTYPE_PPP_ETHER
100	LINKTYPE_ATM_RFC1483
101	LINKTYPE_RAW
104	LINKTYPE_C_HDLC
105	LINKTYPE_IEEE802_11
107	LINKTYPE_FRELAY
108	LINKTYPE_LOOP
113	LINKTYPE_LINUX_SLL
114	LINKTYPE_LTALK
117	LINKTYPE_PFLOG
119	LINKTYPE_PRISM_HEADER
122	LINKTYPE_IP_OVER_FC
123	LINKTYPE_SUNATM
127	LINKTYPE_IEEE802_11_RADIO
129	LINKTYPE_ARCNET_LINUX
138	LINKTYPE_APPLE_IP_OVER_IEEE1394
139	LINKTYPE_MTP2_WITH_PHDR
140	LINKTYPE_MTP2
141	LINKTYPE_MTP3
142	LINKTYPE_SCCP
143	LINKTYPE_DOCSIS
144	LINKTYPE_LINUX_IRDA
147-162	LINKTYPE_USER0-LINKTYPE-USER15
163	LINKTYPE_IEEE802_11_RADIO_AVS
166	LINKTYPE_PPP_PPPD
169	LINKTYPE_GPRS_LLC
177	LINKTYPE_LINUX_LAPD
187	LINKTYPE_BLUETOOTH_HCI_H4
189	LINKTYPE_USB_LINUX
192	LINKTYPE_PPI
195	LINKTYPE_IEEE802_15_4
196	LINKTYPE_SITA
197	LINKTYPE_ERF
201	LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR
202	LINKTYPE_AX25_KISS
203	LINKTYPE_LAPD
204	LINKTYPE_PPP_WITH_DIR
205	LINKTYPE_C_HDLC_WITH_DIR
206	LINKTYPE_FRELAY_WITH_DIR
209	LINKTYPE_IPMB_LINUX
215	LINKTYPE_IEEE802_15_4_NONASK_PHY
220	LINKTYPE_USB_LINUX_MMAPPED
224	LINKTYPE_FC_2
225	LINKTYPE_FC_2_WITH_FRAME_DELIMS
226	LINKTYPE_IPNET
227	LINKTYPE_CAN_SOCKETCAN
228	LINKTYPE_IPV4
229	LINKTYPE_IPV6
230	LINKTYPE_IEEE802_15_4_NOFCS
231	LINKTYPE_DBUS
235	LINKTYPE_DVB_CI
236	LINKTYPE_MUX27010
237	LINKTYPE_STANAG_5066_D_PDU
239	LINKTYPE_NFLOG
240	LINKTYPE_NETANALYZER
241	LINKTYPE_NETANALYZER_TRANSPARENT
242	LINKTYPE_IPOIB
243	LINKTYPE_MPEG_2_TS
244	LINKTYPE_NG40
245	LINKTYPE_NFC_LLCP

COPYRIGHT
=========

Copyright 2012-2021 Robert Krause

Pcapfix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or any later version.

Pcapfix is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
Pcapfix. If not, see http://www.gnu.org/licenses/.
