|author||guy <guy>||2008-10-23 05:56:59 +0000|
|committer||guy <guy>||2008-10-23 05:56:59 +0000|
Add a man page describing the pcap file format.
Refer to it from the pcap_open_offline() and pcap_dump_open() man pages (so they are now generated). Update .cvsignore.
Diffstat (limited to 'pcap-savefile.manfile.in')
1 files changed, 123 insertions, 0 deletions
diff --git a/pcap-savefile.manfile.in b/pcap-savefile.manfile.in
new file mode 100644
@@ -0,0 +1,123 @@
+.\" @(#) $Header: /tcpdump/master/libpcap/pcap-savefile.manfile.in,v 1.1 2008-10-23 05:56:59 guy Exp $
+.\" Copyright (c) 1994, 1996, 1997
+.\" The Regents of the University of California. All rights reserved.
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that: (1) source code distributions
+.\" retain the above copyright notice and this paragraph in its entirety, (2)
+.\" distributions including binary code include the above copyright notice and
+.\" this paragraph in its entirety in the documentation or other materials
+.\" provided with the distribution, and (3) all advertising materials mentioning
+.\" features or use of this software display the following acknowledgement:
+.\" ``This product includes software developed by the University of California,
+.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+.\" the University nor the names of its contributors may be used to endorse
+.\" or promote products derived from this software without specific prior
+.\" written permission.
+.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+.TH PCAP-SAVEFILE @MAN_FILE_FORMATS@ "21 October 2008"
+pcap-savefile \- libpcap savefile format
+NOTE: applications and libraries should, if possible, use libpcap to
+read savefiles, rather than having their own code to read savefiles.
+If, in the future, a new file format is supported by libpcap,
+applications and libraries using libpcap to read savefiles will be able
+to read the new format of savefiles, but applications and libraries
+using their own code to read savefiles will have to be changed to
+support the new file format.
+``Savefiles'' read and written by libpcap and applications using libpcap
+start with a per-file header. The format of the per-file header is:
+c | c
+Major version Minor version
+Time zone offset
+Time stamp accuracy
+Link-layer header type
+All fields in the per-file header are in the byte order of the host
+writing the file. The first field in the per-file header is a 4-byte
+magic number, with the value 0xa1b2c3d4. The magic number, when read by
+a host with the same byte order as the host that wrote the file, will
+have the value 0xa1b2c3d4, and, when read by a host with the opposite
+byte order as the host that wrote the file, will have the value
+0xd4c3b2a1. That allows software reading the file to determine whether
+the byte order of the host that wrote the file is the same as the byte
+order of the host on which the file is being read, and thus whether the
+values in the per-file and per-packet headers need to be byte-swapped.
+Following this are:
+A 2-byte file format major version number; the current version number is
+A 2-byte file format minor version number; the current version number is
+A 4-byte time zone offset; this is always 0.
+A 4-byte number giving the accuracy of time stamps in the file; this is
+A 4-byte number giving the "snapshot length" of the capture; packets
+longer than the snapshot length are truncated to the snapshot length, so
+that, if the snapshot length is
+.IR N ,
+only the first
+bytes of a packet longer than
+bytes will be saved in the capture.
+a 4-byte number giving the link-layer header type for packets in the
+Following the per-file header are zero or more packets; each packet
+begins with a per-packet header, which is immediately followed by the
+raw packet data. The format of the per-packet header is:
+Time stamp, seconds value
+Time stamp, microseconds value
+Length of captured packet data
+Un-truncated length of the packet data
+All fields in the per-packet header are in the byte order of the host
+writing the file. The per-packet header begins with a time stamp giving
+the approximate time the packet was captured; the time stamp consists of
+a 4-byte value, giving the time in seconds since January 1, 1970,
+00:00:00 UTC, followed by a 4-byte value, giving the time in
+microseconds since that second. Following that are a 4-byte value
+giving the number of bytes of captured data that follow the per-packet
+header and a 4-byte value giving the number of bytes that would have
+been present had the packet not been truncated by the snapshot length.
+The two lengths will be equal if the number of bytes of packet data are
+less than or equal to the snapshot length.
+.SH SEE ALSO