Commit Graph

105 Commits

Author SHA1 Message Date
Herbert Xu
89114afd43 [NET] gso: Add skb_is_gso
This patch adds the wrapper function skb_is_gso which can be used instead
of directly testing skb_shinfo(skb)->gso_size.  This makes things a little
nicer and allows us to change the primary key for indicating whether an skb
is GSO (if we ever want to do that).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-07-08 13:34:32 -07:00
Andrey Savochkin
69ee20a58f [BRIDGE]: br_dump_ifinfo index fix
Fix for inability of br_dump_ifinfo to handle non-zero start index:
loop index never increases when entered with non-zero start.
Spotted by Kirill Korotaev.

Signed-off-by: Andrey Savochkin <saw@swsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-07-03 19:50:14 -07:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Herbert Xu
576a30eb64 [NET]: Added GSO header verification
When GSO packets come from an untrusted source (e.g., a Xen guest domain),
we need to verify the header integrity before passing it to the hardware.

Since the first step in GSO is to verify the header, we can reuse that
code by adding a new bit to gso_type: SKB_GSO_DODGY.  Packets with this
bit set can only be fed directly to devices with the corresponding bit
NETIF_F_GSO_ROBUST.  If the device doesn't have that bit, then the skb
is fed to the GSO engine which will allow the packet to be sent to the
hardware if it passes the header check.

This patch changes the sg flag to a full features flag.  The same method
can be used to implement TSO ECN support.  We simply have to mark packets
with CWR set with SKB_GSO_ECN so that only hardware with a corresponding
NETIF_F_TSO_ECN can accept them.  The GSO engine can either fully segment
the packet, or segment the first MTU and pass the rest to the hardware for
further segmentation.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29 16:57:53 -07:00
Herbert Xu
37c3185a02 [NET]: Added GSO toggle
This patch adds a generic segmentation offload toggle that can be turned
on/off for each net device.  For now it only supports in TCPv4.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-23 02:07:36 -07:00
Herbert Xu
7967168cef [NET]: Merge TSO/UFO fields in sk_buff
Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not
going to scale if we add any more segmentation methods (e.g., DCCP).  So
let's merge them.

They were used to tell the protocol of a packet.  This function has been
subsumed by the new gso_type field.  This is essentially a set of netdev
feature bits (shifted by 16 bits) that are required to process a specific
skb.  As such it's easy to tell whether a given device can process a GSO
skb: you just have to and the gso_type field and the netdev's features
field.

I've made gso_type a conjunction.  The idea is that you have a base type
(e.g., SKB_GSO_TCPV4) that can be modified further to support new features.
For example, if we add a hardware TSO type that supports ECN, they would
declare NETIF_F_TSO | NETIF_F_TSO_ECN.  All TSO packets with CWR set would
have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO
packets would be SKB_GSO_TCPV4.  This means that only the CWR packets need
to be emulated in software.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-23 02:07:29 -07:00
Herbert Xu
2c6cc0d853 [BRIDGE]: Add support for NETIF_F_HW_CSUM devices
As it is the bridge will only ever declare NETIF_F_IP_CSUM even if all
its constituent devices support NETIF_F_HW_CSUM.  This patch fixes
this by supporting the first one out of NETIF_F_NO_CSUM,
NETIF_F_HW_CSUM, and NETIF_F_IP_CSUM that is supported by all
constituent devices.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 22:06:45 -07:00
Herbert Xu
8648b3053b [NET]: Add NETIF_F_GEN_CSUM and NETIF_F_ALL_CSUM
The current stack treats NETIF_F_HW_CSUM and NETIF_F_NO_CSUM
identically so we test for them in quite a few places.  For the sake
of brevity, I'm adding the macro NETIF_F_GEN_CSUM for these two.  We
also test the disjunct of NETIF_F_IP_CSUM and the other two in various
places, for that purpose I've added NETIF_F_ALL_CSUM.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 22:06:05 -07:00
Herbert Xu
b38dfee3d6 [NET]: skb_trim audit
I found a few more spots where pskb_trim_rcsum could be used but were not.
This patch changes them to use it.

Also, sk_filter can get paged skb data.  Therefore we must use pskb_trim
instead of skb_trim.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:20 -07:00
Stephen Hemminger
11dc1f36a6 [BRIDGE]: netlink interface for link management
Add basic netlink support to the Ethernet bridge. Including:
 * dump interfaces in bridges
 * monitor link status changes
 * change state of bridge port

For some demo programs see:
	http://developer.osdl.org/shemminger/prototypes/brnl.tar.gz

These are to allow building a daemon that does alternative
implementations of Spanning Tree Protocol.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:26:14 -07:00
Stephen Hemminger
c090971326 [BRIDGE]: fix module startup error handling
Return address in use, if some other kernel code has the SAP.
Propogate out error codes from netfilter registration and unwind.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:26:12 -07:00
Stephen Hemminger
9ef513bed6 [BRIDGE]: optimize conditional in forward path
Small optimizations of bridge forwarding path.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:26:10 -07:00
Jiri Benc
36485707bb [BRIDGE]: fix locking and memory leak in br_add_bridge
There are several bugs in error handling in br_add_bridge:
- when dev_alloc_name fails, allocated net_device is not freed
- unregister_netdev is called when rtnl lock is held
- free_netdev is called before netdev_run_todo has a chance to be run after
  unregistering net_device

Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-05 16:39:34 -07:00
Stephen Hemminger
387e2b0439 [BRIDGE]: need to ref count the LLC sap
Bridge will OOPS on removal if other application has the SAP open.
The bridge SAP might be shared with other usages, so need
to do reference counting on module removal rather than explicit
close/delete.

Since packet might arrive after or during removal, need to clear
the receive function handle, so LLC only hands it to user (if any).

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-23 15:20:25 -07:00
Philip Craig
5c170a09d9 [NETFILTER]: fix format specifier for netfilter log targets
The prefix argument for nf_log_packet is a format specifier,
so don't pass the user defined string directly to it.

Signed-off-by: Philip Craig <philipc@snapgear.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-19 02:15:47 -07:00
Stephen Hemminger
ac05202e8b [BRIDGE]: Do sysfs registration inside rtnl.
Now that netdevice sysfs registration is done as part of
register_netdevice; bridge code no longer has to be tricky when adding
it's kobjects to bridges.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-10 13:21:53 -07:00
Stephen Hemminger
1c29fc4989 [BRIDGE]: keep track of received multicast packets
It makes sense to add this simple statistic to keep track of received
multicast packets.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-05 17:07:13 -07:00
Stephen Hemminger
85ca719e57 [BRIDGE]: allow full size vlan packets
Need to allow for VLAN header when bridging.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-26 02:39:19 -07:00
Jayachandran C
18bc89aa25 [EBTABLES]: Clean up vmalloc usage in net/bridge/netfilter/ebtables.c
Make all the vmalloc calls in net/bridge/netfilter/ebtables.c follow
the standard convention.  Remove unnecessary casts, and use '*object'
instead of 'type'.

Signed-off-by: Jayachandran C. <c.jayachandran@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-20 00:14:49 -07:00
Jayachandran C
7ad4d2f690 [BRIDGE] ebtables: fix allocation in net/bridge/netfilter/ebtables.c
Allocate an array of 'struct ebt_chainstack *', the current code allocates
array of 'struct ebt_chainstack'.

akpm: converted to use the

	foo = alloc(sizeof(*foo))

form.  Which would have prevented this from happening in the first place.

akpm: also removed unneeded typecast.

akpm: what on earth is this code doing anyway?  cpu_possible_map can be
sparse..

Signed-off-by: Jayachandran C. <c.jayachandran@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-11 17:25:38 -07:00
Stephen Hemminger
b7595b4955 [BRIDGE]: receive link-local on disabled ports.
This change allows link local packets (like 802.3ad and Spanning Tree
Protocol) to be processed even when the bridge is not using the port.
It fixes the chicken-egg problem for bridging a bonded device, and
may also fix problems with spanning tree failover.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-11 17:21:05 -07:00
KAMEZAWA Hiroyuki
6f91204225 [PATCH] for_each_possible_cpu: network codes
for_each_cpu() actually iterates across all possible CPUs.  We've had mistakes
in the past where people were using for_each_cpu() where they should have been
iterating across only online or present CPUs.  This is inefficient and
possibly buggy.

We're renaming for_each_cpu() to for_each_possible_cpu() to avoid this in the
future.

This patch replaces for_each_cpu with for_each_possible_cpu under /net

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 06:18:31 -07:00
Patrick McHardy
2e2f7aefa8 [NETFILTER]: Fix fragmentation issues with bridge netfilter
The conntrack code doesn't do re-fragmentation of defragmented packets
anymore but relies on fragmentation in the IP layer. Purely bridged
packets don't pass through the IP layer, so the bridge netfilter code
needs to take care of fragmentation itself.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-09 22:25:23 -07:00
Andrew Morton
65b4b4e81a [NETFILTER]: Rename init functions.
Every netfilter module uses `init' for its module_init() function and
`fini' or `cleanup' for its module_exit() function.

Problem is, this creates uninformative initcall_debug output and makes
ctags rather useless.

So go through and rename them all to $(filename)_init and
$(filename)_fini.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-28 17:02:48 -08:00
Peter Chubb
4dc6d9cc38 [BRIDGE]: Unaligned accesses in the ethernet bridge
I see lots of
	kernel unaligned access to 0xa0000001009dbb6f, ip=0xa000000100811591
	kernel unaligned access to 0xa0000001009dbb6b, ip=0xa0000001008115c1
	kernel unaligned access to 0xa0000001009dbb6d, ip=0xa0000001008115f1
messages in my logs on IA64 when using the ethernet bridge with 2.6.16.

Appended is a patch to fix them.

Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-24 15:44:57 -08:00
Andrew Morton
b3e83d6d18 [BRIDGE]: Remove duplicate const from is_link_local() argument type.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 23:00:56 -08:00
Stephen Hemminger
12ac84c4a9 [BRIDGE]: use LLC to send STP
The bridge code can use existing LLC output code when building
spanning tree protocol packets.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:59:49 -08:00
Stephen Hemminger
fda93d92d7 [BRIDGE]: allow show/store of group multicast address
Bridge's communicate with each other using Spanning Tree Protocol
over a standard multicast address. There are times when testing or
layering bridges over existing topologies or tunnels, when it is
useful to use alternative multicast addresses for STP packets.

The 802.1d standard has some unused addresses, that can be used for this.
This patch is restrictive in that it only allows one of the possible
addresses in the standard.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:59:21 -08:00
Stephen Hemminger
cf0f02d04a [BRIDGE]: use llc for receiving STP packets
Use LLC for the receive path of Spanning Tree Protocol packets.
This allows link local multicast packets to be received by
other protocols (if they care), and uses the existing LLC
code to get STP packets back into bridge code.

The bridge multicast address is also checked, so bridges using
other link local multicast addresses are ignored. This allows
for use of different multicast addresses to define separate STP
domains.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:59:06 -08:00
Stephen Hemminger
18fdb2b25b [BRIDGE]: stp timer to jiffies cleanup
Cleanup the get/set of bridge timer value in the packets.
It is clearer not to bury the conversion in macro.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:58:49 -08:00
Stephen Hemminger
f8ae737dee [BRIDGE]: forwarding remove unneeded preempt and bh diasables
Optimize the forwarding and transmit paths. Both places are
called with bottom half/no preempt so there is no need to use
spin_lock_bh or rcu_read_lock.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:58:36 -08:00
Stephen Hemminger
fdeabdefb2 [BRIDGE]: netfilter inline cleanup
Move nf_bridge_alloc from header file to the one place it is
used and optimize it.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:58:21 -08:00
Stephen Hemminger
8b42ec3926 [BRIDGE]: netfilter VLAN macro cleanup
Fix the VLAN macros in bridge netfilter code. Macros should
not depend on magic variables.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:58:05 -08:00
Stephen Hemminger
f8a2602861 [BRIDGE]: netfilter dont use __constant_htons
Only use__constant_htons() for initializers and switch cases.
For other uses, it is just as efficient and clearer to use htons

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:57:46 -08:00
Stephen Hemminger
789bc3e5b6 [BRIDGE]: netfilter whitespace
Run br_netfilter through Lindent to fix whitespace.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:57:32 -08:00
Stephen Hemminger
d5513a7d32 [BRIDGE]: optimize frame pass up
The netfilter hook that is used to receive frames doesn't need to be a
stub.  It is only called in two ways, both of which ignore the return
value.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:57:18 -08:00
Stephen Hemminger
cee4854122 [BRIDGE]: use kzalloc
Use kzalloc versus kmalloc+memset. Also don't need to do
memset() of bridge address since it is in netdev private data
that is already zero'd in alloc_netdev.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:57:03 -08:00
Stephen Hemminger
3b781fa10b [BRIDGE]: use kcalloc
Use kcalloc rather than kmalloc + memset.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:56:50 -08:00
Stephen Hemminger
a95fcacdc3 [BRIDGE]: use setup_timer
Use the now standard setup_timer function.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:56:38 -08:00
Stephen Hemminger
e3efe08e9a [BRIDGE]: remove unneeded bh disables
The STP timers run off softirq (kernel timers), so there is no need to
disable bottom half in the spin locks.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:56:25 -08:00
Andrew Morton
9ebddc1aa3 [BRIDGE] br_netfilter: Warning fixes.
net/bridge/br_netfilter.c: In function `br_nf_pre_routing':
net/bridge/br_netfilter.c:427: warning: unused variable `vhdr'
net/bridge/br_netfilter.c:445: warning: unused variable `vhdr'

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:55:24 -08:00
Andrew Morton
74ca4e5acd [BRIDGE] ebtables: Build fix.
net/bridge/netfilter/ebtables.c:1481: warning: initialization makes pointer from integer without a cast

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:55:02 -08:00
Herbert Xu
cbb042f9e1 [NET]: Replace skb_pull/skb_postpull_rcsum with skb_pull_rcsum
We're now starting to have quite a number of places that do skb_pull
followed immediately by an skb_postpull_rcsum.  We can merge these two
operations into one function with skb_pull_rcsum.  This makes sense
since most pull operations on receive skb's need to update the
checksum.

I've decided to make this out-of-line since it is fairly big and the
fast path where hardware checksums are enabled need to call
csum_partial anyway.

Since this is a brand new function we get to add an extra check on the
len argument.  As it is most callers of skb_pull ignore its return
value which essentially means that there is no check on the len
argument.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:43:56 -08:00
Ingo Molnar
57b47a53ec [NET]: sem2mutex part 2
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>
2006-03-20 22:35:41 -08:00
Gregor Maier
c127437641 [NETFILTER]: Fix wrong option spelling in Makefile for CONFIG_BRIDGE_EBT_ULOG
Signed-off-by: Gregor Maier <gregor@net.in.tum.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-11 18:51:25 -08:00
Stephen Hemminger
125a12ccf3 [BRIDGE]: generate kobject remove event
The earlier round of kobject/sysfs changes to bridge caused
it not to generate a uevent on removal. Don't think any application
cares (not sure about Xen) but since it generates add uevent
it should generate remove as well.

Signed-off-by: Stephen Hemminger <shemmigner@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-04 21:06:23 -08:00
Stephen Hemminger
d32439c0d4 [BRIDGE]: port timer initialization
Initialize the STP timers for a port when it is created,
rather than when it is enabled. This will prevent future race conditions
where timer gets started before port is enabled.

Signed-off-by: Stephen Hemminger <shemmigner@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-04 21:06:21 -08:00
Stephen Hemminger
6e86b89084 [BRIDGE]: fix crash in STP
Bridge would crash because of uninitailized timer if STP is used and
device was inserted into a bridge before bridge was up. This got
introduced when the delayed port checking was added.  Fix is to not
enable STP on port unless bridge is up.

Bugzilla: http://bugzilla.kernel.org/show_bug.cgi?id=6140
Dup:      http://bugzilla.kernel.org/show_bug.cgi?id=6156

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-04 21:06:19 -08:00
Patrick McHardy
bafac2a512 [NETFILTER]: Restore {ipt,ip6t,ebt}_LOG compatibility
The nfnetlink_log infrastructure changes broke compatiblity of the LOG
targets. They currently use whatever log backend was registered first,
which means that if ipt_ULOG was loaded first, no messages will be printed
to the ring buffer anymore.

Restore compatiblity by using the old log functions by default and only use
the nf_log backend if the user explicitly said so.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-27 13:04:17 -08:00
Patrick McHardy
42cf93cd46 [NETFILTER]: Fix bridge netfilter related in xfrm_lookup
The bridge-netfilter code attaches a fake dst_entry with dst->ops == NULL
to purely bridged packets. When these packets are SNATed and a policy
lookup is done, xfrm_lookup crashes because it tries to dereference
dst->ops.

Change xfrm_lookup not to dereference dst->ops before checking for the
DST_NOXFRM flag and set this flag in the fake dst_entry.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-23 16:10:51 -08:00