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the LIBpcap interface to various kernel packet capture mechanism

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SUNOS4
bpf/net
lbl
linux-include/netinet
CHANGES
FILES
INSTALL
Makefile.in
README
VERSION
aclocal.m4
bpf_dump.c
bpf_image.c
config.guess
config.sub
configure
configure.in
etherent.c
ethertype.h
gencode.c
gencode.h
grammar.y
inet.c
install-sh
mkdep
nametoaddr.c
optimize.c
pcap-bpf.c
pcap-dlpi.c
pcap-enet.c
pcap-int.h
pcap-linux.c
pcap-namedb.h
pcap-nit.c
pcap-nit.h
pcap-null.c
pcap-pf.c
pcap-pf.h
pcap-snit.c
pcap-snoop.c
pcap.3
pcap.c
pcap.h
ppp.h
savefile.c
scanner.l

README

@(#) $Header: /tcpdump/master/libpcap/README,v 1.18.1.1.2.1 2000-06-11 16:39:20 mcr Exp $ (LBL)

LIBPCAP 0.5
Now maintained by "The Tcpdump Group"
Send patches to patches@tcpdump.org
See 		www.tcpdump.org

formerly from 	Lawrence Berkeley National Laboratory
		Network Research Group <libpcap@ee.lbl.gov>
		ftp://ftp.ee.lbl.gov/libpcap.tar.Z (0.4)

This directory contains source code for libpcap, a system-independent
interface for user-level packet capture.  libpcap provides a portable
framework for low-level network monitoring.  Applications include
network statistics collection, security monitoring, network debugging,
etc.  Since almost every system vendor provides a different interface
for packet capture, and since we've developed several tools that
require this functionality, we've created this system-independent API
to ease in porting and to alleviate the need for several
system-dependent packet capture modules in each application.

Note well: this interface is new and is likely to change.

The libpcap interface supports a filtering mechanism based on the
architecture in the BSD packet filter.  BPF is described in the 1993
Winter Usenix paper ``The BSD Packet Filter: A New Architecture for
User-level Packet Capture''.  A compressed postscript version is in:

	ftp://ftp.ee.lbl.gov/papers/bpf-usenix93.ps.Z.

Although most packet capture interfaces support in-kernel filtering,
libpcap utilizes in-kernel filtering only for the BPF interface.
On systems that don't have BPF, all packets are read into user-space
and the BPF filters are evaluated in the libpcap library, incurring
added overhead (especially, for selective filters).  Ideally, libpcap
would translate BPF filters into a filter program that is compatible
with the underlying kernel subsystem, but this is not yet implemented.

BPF is standard in 4.4BSD, BSD/OS, NetBSD, FreeBSD, and OpenBSD.  DEC OSF/1
uses the packetfilter interface but has been extended to accept BPF
filters (which libpcap utilizes).  Also, you can add BPF filter support
to Ultrix using the kernel source and/or object patches available in:

	ftp://gatekeeper.dec.com/pub/DEC/net/bpfext42.tar.Z.

Problems, bugs, questions, desirable enhancements, source code
contributions, etc., should be sent to the email address
"patches@tcpdump.org".

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