linux/net
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
..
802 [SNAP]: Remove leftover unused hdr variable 2006-03-20 22:45:37 -08:00
8021q [NET]: Replace skb_pull/skb_postpull_rcsum with skb_pull_rcsum 2006-03-20 22:43:56 -08:00
appletalk [NET]: Fix ipx/econet/appletalk/irda ioctl crashes 2006-03-28 17:02:43 -08:00
atm [NEIGH]: Fix IP-over-ATM and ARP interaction. 2006-05-12 14:56:08 -07:00
ax25 [AX.25]: Eleminate HZ from AX.25 kernel interfaces 2006-05-03 23:27:16 -07:00
bluetooth [BLUETOOTH] sco: Possible double free. 2006-04-09 22:25:29 -07:00
bridge [BRIDGE]: Do sysfs registration inside rtnl. 2006-05-10 13:21:53 -07:00
core [NEIGH]: Fix IP-over-ATM and ARP interaction. 2006-05-12 14:56:08 -07:00
dccp [DCCP]: Fix sock_orphan dead lock 2006-05-05 17:09:13 -07:00
decnet [DECNET]: Fix level1 router hello 2006-05-03 23:36:23 -07:00
econet [ECONET]: Convert away from SOCKOPS_WRAPPED 2006-03-28 17:02:43 -08:00
ethernet [NET] ethernet: Fix first packet goes out with MAC 00:00:00:00:00:00 2006-02-23 16:18:01 -08:00
ieee80211 [PATCH] softmac: make non-operational after being stopped 2006-05-05 16:55:22 -04:00
ipv4 [IPV4]: ip_options_fragment() has no effect on fragmentation 2006-05-09 15:18:50 -07:00
ipv6 [IPV6]: skb leakage in inet6_csk_xmit 2006-05-10 13:24:38 -07:00
ipx [NET]: Fix ipx/econet/appletalk/irda ioctl crashes 2006-03-28 17:02:43 -08:00
irda [IRDA]: Removing unused EXPORT_SYMBOLs 2006-05-09 15:25:25 -07:00
key [NET] sem2mutex: net/ 2006-03-20 22:33:17 -08:00
lapb [NET]: Kill skb->list 2005-08-29 15:31:14 -07:00
llc [LLC]: Use pskb_trim_rcsum() in llc_fixup_skb(). 2006-04-19 15:37:13 -07:00
netfilter [NETFILTER]: x_tables: don't use __copy_{from,to}_user on unchecked memory in compat layer 2006-05-03 23:20:27 -07:00
netlink Merge branch 'audit.b10' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current 2006-05-01 21:43:05 -07:00
netrom [NETROM/ROSE]: Kill module init version kernel log messages. 2006-05-05 17:19:26 -07:00
packet [NET]: Fix some whitespace issues in af_packet.c 2006-01-23 16:28:02 -08:00
rose [NETROM/ROSE]: Kill module init version kernel log messages. 2006-05-05 17:19:26 -07:00
rxrpc [PATCH] fix 'defined but not used' warning in net/rxrpc/main.c::rxrpc_initialise 2006-03-25 08:22:52 -08:00
sched [NET_SCHED]: HFSC: fix thinko in hfsc_adjust_levels() 2006-05-11 12:22:03 -07:00
sctp [SCTP]: Fix state table entries for chunks received in CLOSED state. 2006-05-05 17:05:23 -07:00
sunrpc SUNRPC: Dead code in net/sunrpc/auth_gss/auth_gss.c 2006-04-19 13:06:49 -04:00
tipc [NET]: Remove redundant NULL checks before [kv]free 2006-04-18 15:57:55 -07:00
unix [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications 2006-03-25 08:22:56 -08:00
wanrouter [WAN]: Remove broken and unmaintained Sangoma drivers. 2006-04-11 17:28:33 -07:00
x25 [X25]: fix for spinlock recurse and spinlock lockup with timer handler 2006-04-29 18:33:11 -07:00
xfrm [XFRM]: fix incorrect xfrm_policy_afinfo_lock use 2006-04-29 18:33:21 -07:00
compat.c [NETFILTER]: iptables 32bit compat layer 2006-04-01 02:25:19 -08:00
Kconfig Merge branch 'master' 2006-02-07 01:47:12 -05:00
Makefile [TIPC] Initial merge 2006-01-12 14:06:31 -08:00
nonet.c [PATCH] Make most file operations structs in fs/ const 2006-03-28 09:16:06 -08:00
socket.c [PATCH] sockaddr patch 2006-05-01 06:06:10 -04:00
sysctl_net.c [NET]: Fix "sysctl_net.c:36: error: 'core_table' undeclared here" 2005-10-03 14:16:34 -07:00
TUNABLE