linux/net/core
Simon Kelley bd89efc532 [NEIGH]: Fix IP-over-ATM and ARP interaction.
The classical IP over ATM code maintains its own IPv4 <-> <ATM stuff>
ARP table, using the standard neighbour-table code. The
neigh_table_init function adds this neighbour table to a linked list
of all neighbor tables which is used by the functions neigh_delete()
neigh_add() and neightbl_set(), all called by the netlink code.

Once the ATM neighbour table is added to the list, there are two
tables with family == AF_INET there, and ARP entries sent via netlink
go into the first table with matching family. This is indeterminate
and often wrong.

To see the bug, on a kernel with CLIP enabled, create a standard IPv4
ARP entry by pinging an unused address on a local subnet. Then attempt
to complete that entry by doing

ip neigh replace <ip address> lladdr <some mac address> nud reachable

Looking at the ARP tables by using 

ip neigh show

will reveal two ARP entries for the same address. One of these can be
found in /proc/net/arp, and the other in /proc/net/atm/arp.

This patch adds a new function, neigh_table_init_no_netlink() which
does everything the neigh_table_init() does, except add the table to
the netlink all-arp-tables chain. In addition neigh_table_init() has a
check that all tables on the chain have a distinct address family.
The init call in clip.c is changed to call
neigh_table_init_no_netlink().

Since ATM ARP tables are rather more complicated than can currently be
handled by the available rtattrs in the netlink protocol, no
functionality is lost by this patch, and non-ATM ARP manipulation via
netlink is rescued. A more complete solution would involve a rtattr
for ATM ARP entries and some way for the netlink code to give
neigh_add and friends more information than just address family with
which to find the correct ARP table.

[ I've changed the assertion checking in neigh_table_init() to not
  use BUG_ON() while holding neigh_tbl_lock.  Instead we remember that
  we found an existing tbl with the same family, and after dropping
  the lock we'll give a diagnostic kernel log message and a stack dump.
  -DaveM ]

Signed-off-by: Simon Kelley <simon@thekelleys.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-12 14:56:08 -07:00
..
datagram.c [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications 2006-03-25 08:22:56 -08:00
dev.c [NET]: Do sysfs registration as part of register_netdevice. 2006-05-10 13:21:17 -07:00
dev_mcast.c [NET]: Remove more unneeded typecasts on *malloc() 2006-01-11 16:32:14 -08:00
dst.c [PATCH] timer initialization cleanup: DEFINE_TIMER 2005-09-09 14:03:48 -07:00
dv.c [NET]: More kzalloc conversions. 2006-04-09 22:25:48 -07:00
ethtool.c [PATCH] capable/capability.h (net/) 2006-01-11 18:42:14 -08:00
filter.c unaligned access in sk_run_filter() 2006-04-18 15:57:54 -07:00
flow.c [PATCH] for_each_possible_cpu: network codes 2006-04-11 06:18:31 -07:00
gen_estimator.c [NET]: More kzalloc conversions. 2006-04-09 22:25:48 -07:00
gen_stats.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
iovec.c [PATCH] misc verify_area cleanups 2005-05-01 08:59:08 -07:00
link_watch.c [NET] linkwatch: Handle jiffies wrap-around 2006-05-09 15:27:54 -07:00
Makefile [PATCH] net/: fix the WIRELESS_EXT abuse 2006-01-30 20:35:30 -05:00
neighbour.c [NEIGH]: Fix IP-over-ATM and ARP interaction. 2006-05-12 14:56:08 -07:00
net-sysfs.c [NET]: Create netdev attribute_groups with class_device_add 2006-05-06 17:56:03 -07:00
netpoll.c [NET]: Convert RTNL to mutex. 2006-03-20 22:23:58 -08:00
pktgen.c [PKTGEN]: Add MPLS extension. 2006-03-23 01:10:26 -08:00
request_sock.c [NET]: More kzalloc conversions. 2006-04-09 22:25:48 -07:00
rtnetlink.c [PATCH] WE-20 for kernel 2.6.16 2006-03-23 07:12:57 -05:00
scm.c [PATCH] capable/capability.h (net/) 2006-01-11 18:42:14 -08:00
skbuff.c [NET]: Add skb->truesize assertion checking. 2006-04-20 00:10:50 -07:00
sock.c [NET]: add SO_RCVBUF comment 2006-03-31 02:09:36 -08:00
stream.c [NET]: Add skb->truesize assertion checking. 2006-04-20 00:10:50 -07:00
sysctl_net_core.c [IPSEC]: Sync series - core changes 2006-03-20 19:15:11 -08:00
utils.c [PATCH] for_each_possible_cpu: network codes 2006-04-11 06:18:31 -07:00
wireless.c [PATCH] wext: Fix RtNetlink ENCODE security permissions 2006-04-19 17:25:41 -04:00