linux.git/net/atm, branch v2.6.17 Linux kernel source tree [NEIGH]: Fix IP-over-ATM and ARP interaction. 2006-05-12T21:56:08+00:00 Simon Kelley simon@thekelleys.org.uk 2006-05-12T21:56:08+00:00 bd89efc532fe41f867f848144cc8b42054ddf6f9 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> 
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>
[ATM] clip: add module info 2006-04-14T23:01:26+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T23:01:26+00:00 4909e488f65fc729fc0f8d42bd1600c56a8bd83c Add module information Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add module information

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM] clip: notifier related cleanups 2006-04-14T23:00:59+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T23:00:59+00:00 5ff765f3d0b9367319d29ab0c0f55349da2fd53e Cleanup some code around notifier. Don't need (void) casts to ignore return values, and use C90 style initializer. Just ignore unused device events. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Cleanup some code around notifier.  Don't need (void) casts to ignore
return values, and use C90 style initializer. Just ignore unused device
events.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM] clip: get rid of PROC_FS ifdef 2006-04-14T23:00:25+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T23:00:25+00:00 dcdb02752ff13a64433c36f2937a58d93ae7a19e Don't need the ifdef here since create_proc_entry() is stubbed to always return NULL. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Don't need the ifdef here since create_proc_entry() is stubbed to
always return NULL.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM] clip: run through Lindent 2006-04-14T22:59:37+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T22:59:37+00:00 e49e76db031fdfaadb4907a319ea3a1dc9d2925f Run CLIP driver through Lindent script to fix formatting. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Run CLIP driver through Lindent script to fix formatting.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM]: Clip timer race. 2006-04-14T22:56:02+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T22:56:02+00:00 2d9073922bc73f8cb847ce354f0896205f6981a1 By inspection, the clip idle timer code is racy on SMP. Here is a safe version of timer management. Untested, I don't have ATM hardware. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
By inspection, the clip idle timer code is racy on SMP.
Here is a safe version of timer management.
Untested, I don't have ATM hardware.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM]: clip causes unregister hang 2006-04-14T22:07:27+00:00 Stephen Hemminger shemminger@osdl.org 2006-04-14T22:07:27+00:00 f3a0592b37b83e56a7f47826f552b35a2c3b2fc9 If Classical IP over ATM module is loaded, its neighbor table gets populated when permanent neighbor entries are created; but these entries are not flushed when the device is removed. Since the entry never gets flushed the unregister of the network device never completes. This version of the patch also adds locking around the reference to the atm arp daemon to avoid races with events and daemon state changes. (Note: barrier() was never really safe) Bug-reference: http://bugzilla.kernel.org/show_bug.cgi?id=6295 Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
If Classical IP over ATM module is loaded, its neighbor table gets
populated when permanent neighbor entries are created; but these entries
are not flushed when the device is removed. Since the entry never gets
flushed the unregister of the network device never completes.

This version of the patch also adds locking around the reference to
the atm arp daemon to avoid races with events and daemon state changes.
(Note: barrier() was never really safe)

Bug-reference: http://bugzilla.kernel.org/show_bug.cgi?id=6295
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[NET]: sem2mutex part 2 2006-03-21T06:35:41+00:00 Ingo Molnar mingo@elte.hu 2006-03-21T06:35:41+00:00 57b47a53ec4a67691ba32cff5768e8d78fa6c67f Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[NET] sem2mutex: net/ 2006-03-21T06:33:17+00:00 Arjan van de Ven arjan@infradead.org 2006-03-21T06:33:17+00:00 4a3e2f711a00a1feb72ae12fdc749da10179d185 Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ATM]: Fix build after neigh->parms->neigh_destructor change. 2006-03-21T06:30:23+00:00 David S. Miller davem@davemloft.net 2006-03-21T06:30:23+00:00 aa837b5bbd92ca3791345e809d0027594faa738b Signed-off-by: David S. Miller <davem@davemloft.net> 
Signed-off-by: David S. Miller <davem@davemloft.net>