| commit | dd9b20c28461bb706cb180083bc67f80cd7d6359 | [log] [tgz] |
|---|---|---|
| author | Denis Ovsienko <[email protected]> | Sun Nov 20 12:16:02 2022 +0000 |
| committer | Francois-Xavier Le Bail <[email protected]> | Sun Nov 20 13:51:26 2022 +0100 |
| tree | 079fa139ba959c85cd91418f0cebbfe3d1bf8e84 | |
| parent | 2b2db5e306c0e51c2c90e20bf96b6b7fa39dcd46 [diff] |
pcap-filter(7): Refine markup of a few lists. [skip ci] Put each item on a separate line and prevent hyphenation, this way the source is more convenient to edit and the output isn't as much distorted when rendered using man. Do not reorder any items on this occasion: at least in the ICMP and ICMPv6 lists the ordering exactly matches the source code and makes it easy to verify the contents. The ICMPv6 types list comprises different values of the same protocol field rather than different protocol fields, fixup the wording to reflect that consistently with the ICMP types list just above. (cherry picked from commit 0e34fc2bb14d83afab22e657d3038a90572316a8)
To report a security issue please send an e-mail to [email protected].
To report bugs and other problems, contribute patches, request a feature, provide generic feedback etc please see the guidelines for contributing.
The documentation directory has README files about specific operating systems and options.
Anonymous Git is available via:
https://github.com/the-tcpdump-group/libpcap.git
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.
formerly from Lawrence Berkeley National Laboratory Network Research Group <libpcap@ee.lbl.gov> ftp://ftp.ee.lbl.gov/old/libpcap-0.4a7.tar.Z
For some platforms there are README.{system} files that discuss issues with the OS‘s interface for packet capture on those platforms, such as how to enable support for that interface in the OS, if it’s not built in by default.
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'' (compressed PostScript, gzipped PostScript, PDF).
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, OpenBSD, DragonFly BSD, macOS, and Solaris 11; an older, modified and undocumented version is standard in AIX. {DEC OSF/1, Digital UNIX, Tru64 UNIX} uses the packetfilter interface but has been extended to accept BPF filters (which libpcap utilizes).
Linux has a number of BPF based systems, and libpcap does not support any of the eBPF mechanisms as yet, although it supports many of the memory mapped receive mechanisms. See the Linux-specific README for more information.
There's now a rule to make a shared library, which should work on Linux and *BSD, among other platforms.
It sets the soname of the library to libpcap.so.1; this is what it should be, NOT libpcap.so.1.x or libpcap.so.1.x.y or something such as that.
We‘ve been maintaining binary compatibility between libpcap releases for quite a while; there’s no reason to tie a binary linked with libpcap to a particular release of libpcap.