59 Commits

Author SHA1 Message Date
Paweł Gronowski
6a1fb46d48 Merge pull request #50169 from robmry/revert_overlay_refactoring
[28.x]: Revert overlay bug fixes / refactoring
2025-06-13 15:49:07 +00:00
Matthieu MOREL
6d737371b8 fix comparison rule from errorlint
Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>
2025-06-13 08:26:56 +00:00
Rob Murray
78ccc20545 Revert "libn/d/overlay: use netip types more"
This reverts commit d188df0039.

Signed-off-by: Rob Murray <rob.murray@docker.com>
2025-06-11 12:05:26 +01:00
Cory Snider
d188df0039 libn/d/overlay: use netip types more
The netip types are really useful for tracking state in the overlay
driver as they are hashable, unlike net.IP and friends, making them
directly useable as map keys. Converting between netip and net types is
fairly trivial, but fewer conversions is more ergonomic.

The NetworkDB entries for the overlay peer table encode the IP addresses
as strings. We need to parse them to some representation before
processing them further. Parse directly into netip types and pass those
values around to cut down on the number of conversions needed.

The peerDB needs to marshal the keys and entries to structs of hashable
values to be able to insert them into the SetMatrix. Use netip.Addr in
peerEntry so that peerEntry values can be directly inserted into the
SetMatrix without conversions. Use a hashable struct type as the
SetMatrix key to avoid having to marshal the whole struct to a string
and parse it back out.

Use netip.Addr as the map key for the driver's encryption map so the
values do not need to be converted to and from strings. Change the
encryption configuration methods to take netip types so the peerDB code
can pass netip values directly.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2025-05-27 13:47:11 -04:00
Sebastiaan van Stijn
02b4c7cc52 libnetwork/drivers/overlay: fix naked returns, output variables
libnetwork/drivers/overlay/encryption.go:370:2: naked return in func `programSA` with 64 lines of code (nakedret)
        return
        ^

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2025-03-04 13:55:46 +01:00
Sebastiaan van Stijn
89add8c64f libnetwork/drivers/overlay: remove redundant capturing of loop vars (copyloopvar)
libnetwork/drivers/overlay/encryption.go:682:3: The copy of the 'for' variable "sp" can be deleted (Go 1.22+) (copyloopvar)
            sp := sp
            ^
    libnetwork/drivers/overlay/encryption.go:692:3: The copy of the 'for' variable "sa" can be deleted (Go 1.22+) (copyloopvar)
            sa := sa
            ^
    libnetwork/drivers/overlay/peerdb.go:134:3: The copy of the 'for' variable "pEntry" can be deleted (Go 1.22+) (copyloopvar)
            pEntry := pEntry
            ^

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2024-11-12 14:02:12 +01:00
Cory Snider
33564a0c03 libnetwork/d/overlay: support IPv6 transport
The forwarding database (fdb) of Linux VXLAN links are restricted to
entries with destination VXLAN tunnel endpoint (VTEP) address of a
single address family. Which address family is permitted is set when the
link is created and cannot be modified. The overlay network driver
creates VXLAN links such that the kernel only allows fdb entries to be
created with IPv4 destination VTEP addresses. If the Swarm is configured
with IPv6 advertise addresses, creating fdb entries for remote peers
fails with EAFNOSUPPORT (address family not supported by protocol).

Make overlay networks functional over IPv6 transport by configuring the
VXLAN links for IPv6 VTEPs if the local node's advertise address is an
IPv6 address. Make encrypted overlay networks secure over IPv6 transport
by applying the iptables rules to the ip6tables when appropriate.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-11-09 12:04:47 -05:00
Cory Snider
e1d85da306 libnetwork/d/overlay: parse discovery data eagerly
Parse the address strings once and use the binary representation
internally.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-11-09 12:04:47 -05:00
Sebastiaan van Stijn
cff4f20c44 migrate to github.com/containerd/log v0.1.0
The github.com/containerd/containerd/log package was moved to a separate
module, which will also be used by upcoming (patch) releases of containerd.

This patch moves our own uses of the package to use the new module.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2023-10-11 17:52:23 +02:00
Albin Kerouanton
42d34e40f9 libnet: Replace BadRequest with InvalidParameter
InvalidParameter is now compatible with errdefs.InvalidParameter. Thus,
these errors will now return a 400 status code instead of a 500.

Signed-off-by: Albin Kerouanton <albinker@gmail.com>
2023-08-17 16:45:04 +02:00
Sebastiaan van Stijn
7c2665298a libnetwork/types: move GetMinimalIP to overlay-driver and un-export
It was only used in drivers/overlay, and was not a function for any
"type" defined by libnetwork.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2023-07-31 21:00:32 +02:00
Brian Goff
74da6a6363 Switch all logging to use containerd log pkg
This unifies our logging and allows us to propagate logging and trace
contexts together.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2023-06-24 00:23:44 +00:00
Cory Snider
9a692a3802 libn/d/overlay: support encryption on any port
While the VXLAN interface and the iptables rules to mark outgoing VXLAN
packets for encryption are configured to use the Swarm data path port,
the XFRM policies for actually applying the encryption are hardcoded to
match packets with destination port 4789/udp. Consequently, encrypted
overlay networks do not pass traffic when the Swarm is configured with
any other data path port: encryption is not applied to the outgoing
VXLAN packets and the destination host drops the received cleartext
packets. Use the configured data path port instead of hardcoding port
4789 in the XFRM policies.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-05-26 14:36:34 -04:00
Sebastiaan van Stijn
d5dc675d37 Merge pull request #45280 from corhere/libnet/no-overlay-accept-rule
libnetwork/drivers/overlay: stop programming INPUT ACCEPT rule
2023-05-25 21:03:32 +02:00
Sebastiaan van Stijn
ab35df454d remove pre-go1.17 build-tags
Removed pre-go1.17 build-tags with go fix;

    go mod init
    go fix -mod=readonly ./...
    rm go.mod

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2023-05-19 20:38:51 +02:00
Cory Snider
4d04068184 libn/d/overlay: only program xt_bpf rules
Drop support for platforms which only have xt_u32 but not xt_bpf. No
attempt is made to clean up old xt_u32 iptables rules left over from a
previous daemon instance.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-04-05 11:50:03 -04:00
Cory Snider
1e195acee4 libn/d/overlay: stop programming INPUT ACCEPT rule
Encrypted overlay networks are unique in that they are the only kind of
network for which libnetwork programs an iptables rule to explicitly
accept incoming packets. No other network driver does this. The overlay
driver doesn't even do this for unencrypted networks!

Because the ACCEPT rule is appended to the end of INPUT table rather
than inserted at the front, the rule can be entirely inert on many
common configurations. For example, FirewallD programs an unconditional
REJECT rule at the end of the INPUT table, so any ACCEPT rules appended
after it have no effect. And on systems where the rule is effective, its
presence may subvert the administrator's intentions. In particular,
automatically appending the ACCEPT rule could allow incoming traffic
which the administrator was expecting to be dropped implicitly with a
default-DROP policy.

Let the administrator always have the final say in how incoming
encrypted overlay packets are filtered by no longer automatically
programming INPUT ACCEPT iptables rules for them.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-04-05 11:35:19 -04:00
Cory Snider
965eda3b9a libnet/d/overlay: insert the input-drop rule
FirewallD creates the root INPUT chain with a default-accept policy and
a terminal rule which rejects all packets not accepted by any prior
rule. Any subsequent rules appended to the chain are therefore inert.
The administrator would have to open the VXLAN UDP port to make overlay
networks work at all, which would result in all VXLAN traffic being
accepted and defeating our attempts to enforce encryption on encrypted
overlay networks.

Insert the rule to drop unencrypted VXLAN packets tagged for encrypted
overlay networks at the top of the INPUT chain so that enforcement of
mandatory encryption takes precedence over any accept rules configured
by the administrator. Continue to append the accept rule to the bottom
of the chain so as not to override any administrator-configured drop
rules.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-03-22 20:54:01 -04:00
Cory Snider
105b9834fb libnet/d/overlay: add BPF-powered VNI matcher
Some newer distros such as RHEL 9 have stopped making the xt_u32 kernel
module available with the kernels they ship. They do ship the xt_bpf
kernel module, which can do everything xt_u32 can and more. Add an
alternative implementation of the iptables match rule which uses xt_bpf
to implement exactly the same logic as the u32 filter using a BPF
program. Try programming the BPF-powered rules as a fallback when
programming the u32-powered rules fails.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-03-15 19:33:51 -04:00
Cory Snider
44cf27b5fc libnet/d/overlay: extract VNI match rule builder
The iptables rule clause used to match on the VNI of VXLAN datagrams
looks like line noise to the uninitiated. It doesn't help that the
expression is repeated twice and neither copy has any commentary.
DRY out the rule builder to a common function, and document what the
rule does and how it works.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-03-15 19:30:28 -04:00
Cory Snider
142f46cac1 libn/d/overlay: enforce encryption on sandbox init
The iptables rules which make encryption mandatory on an encrypted
overlay network are only programmed once there is a second node
participating in the network. This leaves single-node encrypted overlay
networks vulnerable to packet injection. Furthermore, failure to program
the rules is not treated as a fatal error.

Program the iptables rules to make encryption mandatory before creating
the VXLAN link to guarantee that there is no window of time where
incoming cleartext VXLAN packets for the network would be accepted, or
outgoing cleartext packets be transmitted. Only create the VXLAN link if
programming the rules succeeds to ensure that it fails closed.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-03-15 19:28:11 -04:00
Cory Snider
d4fd582fb2 libnet/d/overlay: document some encryption code
The overlay-network encryption code is woefully under-documented, which
is especially problematic as it operates on under-documented kernel
interfaces. Document what I have puzzled out of the implementation for
the benefit of the next poor soul to touch this code.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-03-15 17:26:24 -04:00
Sebastiaan van Stijn
cd381aea56 libnetwork: fix empty-lines (revive)
libnetwork/etchosts/etchosts_test.go:167:54: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/osl/route_linux.go:185:74: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/osl/sandbox_linux_test.go:323:36: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/bitseq/sequence.go:412:48: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/datastore/datastore_test.go:67:46: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/datastore/mock_store.go:34:60: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/iptables/firewalld.go:202:44: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/iptables/firewalld_test.go:76:36: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/iptables/iptables.go:256:67: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/iptables/iptables.go:303:128: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/networkdb/cluster.go:183:72: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/ipams/null/null_test.go:44:38: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/macvlan/macvlan_store.go:45:52: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/ipam/allocator_test.go:1058:39: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/bridge/port_mapping.go:88:111: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/bridge/link.go:26:90: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/bridge/setup_ipv6_test.go:17:34: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/bridge/setup_ip_tables.go:392:4: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/bridge/bridge.go:804:50: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/ov_serf.go:183:29: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/ov_utils.go:81:64: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/overlay/peerdb.go:172:67: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/peerdb.go:209:67: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/peerdb.go:344:89: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/peerdb.go:436:63: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/overlay.go:183:36: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/drivers/overlay/encryption.go:69:28: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/drivers/overlay/ov_network.go:563:81: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/default_gateway.go:32:43: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/errors_test.go:9:40: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/service_common.go:184:64: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/endpoint.go:161:55: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/store.go:320:33: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/store_linux_test.go:11:38: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/sandbox.go:571:36: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/service_common.go:317:246: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/endpoint.go:550:17: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/sandbox_dns_unix.go:213:106: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/controller.go:676:85: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/agent.go:876:60: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/resolver.go:324:69: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/network.go:1153:92: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/network.go:1955:67: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/network.go:2235:9: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/libnetwork_internal_test.go:336:26: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/resolver_test.go:76:35: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/libnetwork_test.go:303:38: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/libnetwork_test.go:985:46: empty-lines: extra empty line at the end of a block (revive)
    libnetwork/ipam/allocator_test.go:1263:37: empty-lines: extra empty line at the start of a block (revive)
    libnetwork/errors_test.go:9:40: empty-lines: extra empty line at the end of a block (revive)

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2022-09-26 19:21:58 +02:00
Sebastiaan van Stijn
686be57d0a Update to Go 1.17.0, and gofmt with Go 1.17
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-08-24 23:33:27 +02:00
Brian Goff
116f200737 Fix gosec complaints in libnetwork
These were purposefully ignored before but this goes ahead and "fixes"
most of them.
Note that none of the things gosec flagged are problematic, just
quieting the linter here.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-06-25 18:02:03 +02:00
Brian Goff
4b981436fe Fixup libnetwork lint errors
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-06-01 23:48:32 +00:00
Brian Goff
00b2c13a1b Fix some windows issues in libnetwork tests
Fix build constraints for linux-only network drivers

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-06-01 23:48:23 +00:00
Brian Goff
a0a473125b Fix libnetwork imports
After moving libnetwork to this repo, we need to update all the import
paths for libnetwork to point to docker/docker/libnetwork instead of
docker/libnetwork.
This change implements that.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-06-01 21:51:23 +00:00
Benjamin Böhmke
34f4706174 added TODOs for open IPv6 point
Signed-off-by: Benjamin Böhmke <benjamin@boehmke.net>
2020-07-23 16:52:40 +02:00
Billy Ridgway
8dbb5b5a7d Implement NAT IPv6 to fix the issue https://github.com/moby/moby/issues/25407
Signed-off-by: Billy Ridgway <wrridgwa@us.ibm.com>
Signed-off-by: Benjamin Böhmke <benjamin@boehmke.net>
2020-07-19 16:16:51 +02:00
selansen
56ca280b27 VXLAN port configuration - late review comments update
Some review comments came in very late after merging
	#2282. This PR addresses those review comments.

Signed-off-by: selansen <elango.siva@docker.com>
2018-11-14 13:26:56 -05:00
selansen
077ccabc45 VXLAN UDP Port configuration support
This PR chnages allow user to configure VxLAN UDP
port number. By default we use 4789 port number. But this commit
will allow user to configure port number during swarm init.
VxLAN port can't be modified after swarm init.

Signed-off-by: selansen <elango.siva@docker.com>
2018-11-01 15:20:30 -04:00
Josh Soref
a06f1b2c4e Spelling fixes
* addresses
* assigned
* at least
* attachments
* auxiliary
* available
* cleanup
* communicate
* communications
* configuration
* connection
* connectivity
* destination
* encountered
* endpoint
* example
* existing
* expansion
* expected
* external
* forwarded
* gateway
* implementations
* implemented
* initialize
* internally
* loses
* message
* network
* occurred
* operational
* origin
* overlapping
* reaper
* redirector
* release
* representation
* resolver
* retrieve
* returns
* sanbdox
* sequence
* succesful
* synchronizing
* update
* validates

Signed-off-by: Josh Soref <jsoref@gmail.com>
2018-07-12 12:54:44 -07:00
Chris Telfer
06922d2d81 Use fmt precision to limit string length
The previous code used string slices to limit the length of certain
fields like endpoint or sandbox IDs.  This assumes that these strings
are at least as long as the slice length.  Unfortunately, some sandbox
IDs can be smaller than 7 characters.   This fix addresses this issue
by systematically converting format string calls that were taking
fixed-slice arguments to use a precision specifier in the string format
itself.  From the golang fmt package documentation:

    For strings, byte slices and byte arrays, however, precision limits
    the length of the input to be formatted (not the size of the output),
    truncating if necessary. Normally it is measured in runes, but for
    these types when formatted with the %x or %X format it is measured
    in bytes.

This nicely fits the desired behavior: it will limit the number of
runes considered for string interpolation to the precision value.

Signed-off-by: Chris Telfer <ctelfer@docker.com>
2018-07-05 17:44:04 -04:00
Chris Telfer
c97bb41620 Remove race in encrypted overlay key update
Multiple simultaneous updates here would leave the driver in a very
inconsistent state.  The disadvantage to this change is that it requires
holding the driver lock while reprogramming the keys.

Signed-off-by: Chris Telfer <ctelfer@docker.com>
2018-05-01 17:41:47 -04:00
Flavio Crisciani
3e7b6c9cb0 flush peerdb entries on network delete
peerDB was never being flushed on network delete
leaveing behind stale entries

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>
2017-10-02 11:12:35 -07:00
Derek McGowan
710e0664c4 Update logrus to v1.0.1
Fix case sensitivity issue
Update docker and runc vendors

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
2017-08-07 11:20:47 -07:00
Madhu Venugopal
c85473ad37 Merge pull request #1354 from aboch/pol
Few changes in encryption overlay
2017-03-11 18:21:55 -08:00
Alessandro Boch
9272c89bb7 Clear encryption states when joining cluster
- Use the request id for labelling our SAs

Signed-off-by: Alessandro Boch <aboch@docker.com>
2017-03-11 15:52:39 -08:00
Alessandro Boch
91f5b1669e Once a network is encrypted, do not accept clear packets from it
Signed-off-by: Alessandro Boch <aboch@docker.com>
2017-02-18 12:15:54 -08:00
Alessandro Boch
4a04857a68 Fix bug in datapath key rotation in 1-1 NAT case
- It was not using the advertise IP to construct the SPI

Signed-off-by: Alessandro Boch <aboch@docker.com>
2017-02-10 18:33:06 -08:00
Alessandro Boch
bee7d9219f Properly construct CIDR in policy selector
- Current code programs src/dst cidr like 192.168.100.126/128

Signed-off-by: Alessandro Boch <aboch@docker.com>
2017-02-03 23:14:58 -08:00
Daehyeok Mun
7f473c779a Refactoring logrus import and formatting
This fix tries to fix logrus formatting by removing `f` from
`logrus.[Error|Warn|Debug|Fatal|Panic|Info]f` when formatting string
is not present.
Also fix import name to use original project name 'logrus' instead of
'log'

Signed-off-by: Daehyeok Mun <daehyeok@gmail.com>
2016-11-08 12:42:41 -07:00
Alessandro Boch
d4f3963a26 In overlay driver reset any state on setkey()
Signed-off-by: Alessandro Boch <aboch@docker.com>
2016-09-19 14:03:55 -07:00
Madhu Venugopal
f142339334 Merge pull request #1356 from aboch/isb
Fix bug in ipsec key rotation
2016-07-25 19:16:01 -07:00
Alessandro Boch
bc6a60dae5 Fix bug in ipsec key rotation
- which would leave a stale state behind
  at each key rotation.

Signed-off-by: Alessandro Boch <aboch@docker.com>
2016-07-25 16:23:53 -07:00
Alessandro Boch
8bc99ae906 Check for advertise IP when deriving ipsec nodes
- We need to compare the node notification IP with
  the advertise address otherwise when the advertise
  address is different from the local address (this
  is for the public address outside of the host
  that maps 1-to-1 to the local private address)
  the local IP will be acocunted as an ipsec host
  and extra states will be programmed for it.

Signed-off-by: Alessandro Boch <aboch@docker.com>
2016-07-25 12:07:48 -07:00
Alessandro Boch
801bd7b3b2 Allow user to set the overlay network's mtu
- Being a driver specific flag, user needs to
  account for vxlan and, if enabled, ipsec overhead

Signed-off-by: Alessandro Boch <aboch@docker.com>
2016-07-23 22:39:29 -07:00
Alessandro Boch
e415b1f495 Do not use 4 byte ip addresses in encryption code
- Because of a bug in the netlink xfrm code, our code will
  fail to find and remove the states. While we could wait
  for the netlink library fix, there is no longer a need to
  convert the parsed IP addresses to the canonical notation
  given the previous SPI computation (which worked on that
  4 byte address assumption) is now replaced by the fnv hash.
- Also modify driver option that enables ipsec to "encrypted"

Signed-off-by: Alessandro Boch <aboch@docker.com>
2016-07-23 19:00:47 -07:00
Alessandro Boch
6b486d88e6 Merge pull request #1337 from mavenugo/adv-addr
Add advertise-addr support
2016-07-21 09:51:51 -07:00