pcap.txt

libcap是常用的linux抓包程序,属于open source项目.

       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Cell Size            |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      |                                                               |
      |                        Fixed Size Data                        |
      |                                                               |
      |              /* variable length, byte-aligned */              |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 12: Fixed Length Block format.

   The fields have the following meaning:

   o  Cell size: the size of the blocks contained in the data field.

   o  Fixed Size Data: data of this block.


5.5 Directory Block (experimental)

   If present, this block contains the following information:

   o  number of indexed packets (N)

   o  table with position and length of any indexed packet (N entries)

   A directory block must be followed by at least N packets, otherwise
   it must be considered invalid. It can be used to efficiently load
   portions of the file to memory and to support operations on memory
   mapped files. This block can be added by tools like network analyzers
   as a consequence of file processing.

5.6 Traffic Statistics and Monitoring Blocks (experimental)

   One or more blocks could be defined to contain network statistics or
   traffic monitoring information. They could be use to store data
   collected from RMON or Netflow probes, or from other network
   monitoring tools.

5.7 Event/Security Block (experimental)

   This block could be used to store events. Events could contain
   generic information (for example network load over 50%, server
   down...) or security alerts. An event could be:



Degioanni & Risso       Expires August 30, 2004                [Page 25]

Internet-Draft    PCAP New Generation Dump File Format        March 2004


   o  skipped, if the application doesn't know how to do with it

   o  processed independently by the packets. In other words, the
      applications skips the packets and processes only the alerts

   o  processed in relation to packets: for example, a security tool
      could load only the packets of the file that are near a security
      alert; a monitorg tool could skip the packets captured while the
      server was down.










































Degioanni & Risso       Expires August 30, 2004                [Page 26]

Internet-Draft    PCAP New Generation Dump File Format        March 2004


6. Conclusions

   The file format proposed in this document should be very versatile
   and satisfy a wide range of applications. In the simplest case, it
   can contain a raw dump of the network data, made of a series of
   Simple Packet Blocks. In the most complex case, it can be used as a
   repository for heterogeneous information. In every case, the file
   remains easy to parse and an application can always skip the data it
   is not interested in; at the same time, different applications can
   share the file, and each of them can benfit of the information
   produced by the others. Two or more files can be concatenated
   obtaining another valid file.







































Degioanni & Risso       Expires August 30, 2004                [Page 27]

Internet-Draft    PCAP New Generation Dump File Format        March 2004


7. Most important open issues

   o  Data, in the file, must be byte or word aligned? Currently, the
      structure of this document is not consistent with respect to this
      point.














































Degioanni & Risso       Expires August 30, 2004                [Page 28]

Internet-Draft    PCAP New Generation Dump File Format        March 2004


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights. Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11. Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard. Please address the information to the IETF Executive
   Director.


Full Copyright Statement

   Copyright (C) The Internet Society (2004). All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION



Degioanni & Risso       Expires August 30, 2004                [Page 29]

Internet-Draft    PCAP New Generation Dump File Format        March 2004


   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































Degioanni & Risso       Expires August 30, 2004                [Page 30]