[Xorp-cvs] XORP cvs commit: xorp/fea/data_plane/io

[Pavlin Radoslavov]

CVSROOT:	/usr/local/share/doc/apache/cvs
Module name:	xorp
Changes by:	pavlin at xorpc.icir.org	2007-10-19 01:12:28 UTC

XORP CVS repository


Modified files:
	fea/data_plane/io io_link_pcap.cc io_link_pcap.hh 

Log message:
	Fix the mechanism for joining L2 MAC addresses:
	
	* We need to use a regular socket "socket(AF_INET, SOCK_DGRAM, 0)"
	  for the ioctl(SIOCADDMULTI) and ioctl(SIOCDELMULTI) system calls
	  instead of the pcap(3) derived file descriptor.
	
	* On FreeBSD and DragonFlyBSD the MAC address needs to be setup
	  inside sockaddr_dl aligned address storage in a special way
	  that is different from NetBSD and OpenBSD (and Linux).
	
	Note that as of FreeBSD-6.2, the FreeBSD kernel has some bugs
	when it comes to using ioctl(SIOCADDMULTI) and ioctl(SIOCDELMULTI)
	to manipulate directly the L2 multicast membership on interface.
	In particular, the kernel doesn't deal with duplicate joins, the
	leave requests fail, and "netstat -ian" fails to print the joined
	groups. See the following email thread for details:
	
	http://lists.freebsd.org/pipermail/freebsd-net/2007-February/013120.html
	
	However, those problems have been fixed (by Bruce M. Simpson) in the
	FreeBSD CVS repository. The RELENG_6 fixes are:
	
	src/usr.bin/netstat/mcast.c,v 1.2.8.1 2007/03/14 14:10:22 bms
	src/sys/net/if.c,v 1.234.2.18 2007/03/08 13:15:27 bms
	
	After the fix, "netstat -gn" will print the L2 joined groups as well.
	Those fixes are in FreeBSD-current as well so they should appear
	in the next FreeBSD release.
	
	It appears that DragonFlyBSD (as of DragonFlyBSD-1.8) has similar
	problems, but there is no indication it has been fixed even in the
	most recent DragonFly-1.10.1 release.
	
	For the record, the ioctl(SIOCADDMULTI) and ioctl(SIOCDELMULTI)
	mechanism seems to work fine on NetBSD-3.1 and OpenBSD-4.1.
	However, on NetBSD the ifmcstat(8) program needs to be used
	to print the L2 membership ("netstat -ian" or "netstat -gn" don't
	print it).
	It appears that OpenBSD doesn't have ifmcstat(8), and "netstat"
	doesn't print that info, so it is unclear what OS tool can be used
	for that purpose.
	Apparently, the NetBSD source code for ifmcstat(8) from NetBSD can
	be compiled as-is on OpenBSD and it actually works.

Revision  Changes                                 Path
1.8       +56 -10;  commitid: 1498a4717fbee7ea6;  xorp/fea/data_plane/io/io_link_pcap.cc
1.5       +2 -1;  commitid: 1498a4717fbee7ea6;    xorp/fea/data_plane/io/io_link_pcap.hh