Commit Graph

114 Commits (166da8f7108ef10587adfa8165839d9487b55164)

Author SHA1 Message Date
Matt Keeler b0fcf86140 Change auto config authorizer to allow for future extension
The envisioned changes would allow extra settings to enable dynamically defined auth methods to be used instead of  or in addition to the statically defined one in the configuration.
2020-06-18 15:22:24 -04:00
Matt Keeler 3dbbd2d37d
Implement Client Agent Auto Config
There are a couple of things in here.

First, just like auto encrypt, any Cluster.AutoConfig RPC will implicitly use the less secure RPC mechanism.

This drastically modifies how the Consul Agent starts up and moves most of the responsibilities (other than signal handling) from the cli command and into the Agent.
2020-06-17 16:49:46 -04:00
Daniel Nephin 068b43df90 Enable gofmt simplify
Code changes done automatically with 'gofmt -s -w'
2020-06-16 13:21:11 -04:00
Hans Hasselberg dfcf45c6cf
tests: use constructor instead init (#8024) 2020-06-04 22:59:06 +02:00
Pierre Souchay 9813ae512b
checks: when a service does not exists in an alias, consider it failing (#7384)
In current implementation of Consul, check alias cannot determine
if a service exists or not. Because a service without any check
is semantically considered as passing, so when no healthchecks
are found for an agent, the check was considered as passing.

But this make little sense as the current implementation does not
make any difference between:
 * a non-existing service (passing)
 * a service without any check (passing as well)

In order to make it work, we have to ensure that when a check did
not find any healthcheck, the service does indeed exists. If it
does not, lets consider the check as failing.
2020-06-04 14:50:52 +02:00
Daniel Nephin 99eb583ebc
Replace goe/verify.Values with testify/require.Equal (#7993)
* testing: replace most goe/verify.Values with require.Equal

One difference between these two comparisons is that go/verify considers
nil slices/maps to be equal to empty slices/maps, where as testify/require
does not, and does not appear to provide any way to enable that behaviour.

Because of this difference some expected values were changed from empty
slices to nil slices, and some calls to verify.Values were left.

* Remove github.com/pascaldekloe/goe/verify

Reduce the number of assertion packages we use from 2 to 1
2020-06-02 12:41:25 -04:00
Daniel Nephin 600645b5f9 Add unconvert linter
To find unnecessary type convertions
2020-05-12 13:47:25 -04:00
Pierre Souchay 2a8bf45e38
agent: show warning when enable_script_checks is enabled without safty net (#7437)
In order to enforce a bit security on Consul agents, add a new method in agent
to highlight possible security issues.

This does not return an error for now, but might in the future.

For now, it detects issues such as:

https://www.hashicorp.com/blog/protecting-consul-from-rce-risk-in-specific-configurations/

This would display this kind of messages:

```
2020-03-11T18:27:49.873+0100 [ERROR] agent: [SECURITY] issue: error="using enable-script-checks without ACLs and without allow_write_http_from is DANGEROUS, use enable-local-script-checks instead see https://www.hashicorp.com/blog/protecting-consul-from-rce-risk-in-specific-configurations/"
```
2020-04-02 09:59:23 +02:00
Daniel Nephin e759daafdd Rename NewTestAgentWithFields to StartTestAgent
This function now only starts the agent.

Using:

git grep -l 'StartTestAgent(t, true,' | \
        xargs sed -i -e 's/StartTestAgent(t, true,/StartTestAgent(t,/g'
2020-03-31 17:14:55 -04:00
Daniel Nephin f9f6b14533 Convert the remaining calls to NewTestAgentWithFields
After removing the t.Name() parameter with sed, convert the last few tests which
use a custom name to call NewTestAgentWithFields instead.
2020-03-31 17:14:55 -04:00
Daniel Nephin 475659a132 Remove name from NewTestAgent
Using:

git grep -l 'NewTestAgent(t, t.Name(),' | \
    xargs sed -i -e 's/NewTestAgent(t, t.Name(),/NewTestAgent(t,/g'
2020-03-31 16:13:44 -04:00
Daniel Nephin ad7c78f134 Remove t.Name() from TestAgent.Name
And re-add the name to the logger so that log messages from different agents
in a single can be identified.
2020-03-30 16:47:24 -04:00
Daniel Nephin dd40a1535e testing: reduce verbosity of output log
Previously the log output included the test name twice and a long date
format. The test output is already grouped by test, so adding the test
name did not add any new information. The date and time are only useful
to understand elapsed time, so using a short format should provide
succident detail.

Also fixed a bug in NewTestAgentWithFields where nil was returned
instead of the test agent.
2020-03-30 13:23:13 -04:00
Chris Piraino 136099d834
Fix flakey health check reload test (#7490)
This test would occasionally fail because we checked for a status of
"critical" initially. This races with the actual healthcheck being run
and declared passing.

We instead use a ttl health check so that we don't rely on timing at all.
2020-03-25 09:09:13 -05:00
R.B. Boyer 6adad71125
wan federation via mesh gateways (#6884)
This is like a Möbius strip of code due to the fact that low-level components (serf/memberlist) are connected to high-level components (the catalog and mesh-gateways) in a twisty maze of references which make it hard to dive into. With that in mind here's a high level summary of what you'll find in the patch:

There are several distinct chunks of code that are affected:

* new flags and config options for the server

* retry join WAN is slightly different

* retry join code is shared to discover primary mesh gateways from secondary datacenters

* because retry join logic runs in the *agent* and the results of that
  operation for primary mesh gateways are needed in the *server* there are
  some methods like `RefreshPrimaryGatewayFallbackAddresses` that must occur
  at multiple layers of abstraction just to pass the data down to the right
  layer.

* new cache type `FederationStateListMeshGatewaysName` for use in `proxycfg/xds` layers

* the function signature for RPC dialing picked up a new required field (the
  node name of the destination)

* several new RPCs for manipulating a FederationState object:
  `FederationState:{Apply,Get,List,ListMeshGateways}`

* 3 read-only internal APIs for debugging use to invoke those RPCs from curl

* raft and fsm changes to persist these FederationStates

* replication for FederationStates as they are canonically stored in the
  Primary and replicated to the Secondaries.

* a special derivative of anti-entropy that runs in secondaries to snapshot
  their local mesh gateway `CheckServiceNodes` and sync them into their upstream
  FederationState in the primary (this works in conjunction with the
  replication to distribute addresses for all mesh gateways in all DCs to all
  other DCs)

* a "gateway locator" convenience object to make use of this data to choose
  the addresses of gateways to use for any given RPC or gossip operation to a
  remote DC. This gets data from the "retry join" logic in the agent and also
  directly calls into the FSM.

* RPC (`:8300`) on the server sniffs the first byte of a new connection to
  determine if it's actually doing native TLS. If so it checks the ALPN header
  for protocol determination (just like how the existing system uses the
  type-byte marker).

* 2 new kinds of protocols are exclusively decoded via this native TLS
  mechanism: one for ferrying "packet" operations (udp-like) from the gossip
  layer and one for "stream" operations (tcp-like). The packet operations
  re-use sockets (using length-prefixing) to cut down on TLS re-negotiation
  overhead.

* the server instances specially wrap the `memberlist.NetTransport` when running
  with gateway federation enabled (in a `wanfed.Transport`). The general gist is
  that if it tries to dial a node in the SAME datacenter (deduced by looking
  at the suffix of the node name) there is no change. If dialing a DIFFERENT
  datacenter it is wrapped up in a TLS+ALPN blob and sent through some mesh
  gateways to eventually end up in a server's :8300 port.

* a new flag when launching a mesh gateway via `consul connect envoy` to
  indicate that the servers are to be exposed. This sets a special service
  meta when registering the gateway into the catalog.

* `proxycfg/xds` notice this metadata blob to activate additional watches for
  the FederationState objects as well as the location of all of the consul
  servers in that datacenter.

* `xds:` if the extra metadata is in place additional clusters are defined in a
  DC to bulk sink all traffic to another DC's gateways. For the current
  datacenter we listen on a wildcard name (`server.<dc>.consul`) that load
  balances all servers as well as one mini-cluster per node
  (`<node>.server.<dc>.consul`)

* the `consul tls cert create` command got a new flag (`-node`) to help create
  an additional SAN in certs that can be used with this flavor of federation.
2020-03-09 15:59:02 -05:00
Pierre Souchay 864f7efffa
agent: configuration reload preserves check's statuses for services (#7345)
This fixes issue #7318

Between versions 1.5.2 and 1.5.3, a regression has been introduced regarding health
of services. A patch #6144 had been issued for HealthChecks of nodes, but not for healthchecks
of services.

What happened when a reload was:

1. save all healthcheck statuses
2. cleanup everything
3. add new services with healthchecks

In step 3, the state of healthchecks was taken into account locally,
so at step 3, but since we cleaned up at step 2, state was lost.

This PR introduces the snap parameter, so step 3 can use information from step 1
2020-03-09 12:59:41 +01:00
Chris Piraino 401221de58
Allow users to configure either unstructured or JSON logging (#7130)
* hclog Allow users to choose between unstructured and JSON logging
2020-01-28 17:50:41 -06:00
Aestek ba8fd8296f Add support for dual stack IPv4/IPv6 network (#6640)
* Use consts for well known tagged adress keys

* Add ipv4 and ipv6 tagged addresses for node lan and wan

* Add ipv4 and ipv6 tagged addresses for service lan and wan

* Use IPv4 and IPv6 address in DNS
2020-01-17 09:54:17 -05:00
Matt Keeler 5934f803bf
Sync of OSS changes to support namespaces (#6909) 2019-12-09 21:26:41 -05:00
Matt Keeler 8f0ab0129e
Miscellaneous Fixes (#6896)
Ensure we close the Sentinel Evaluator so as not to leak go routines

Fix a bunch of test logging so that various warnings when starting a test agent go to the ltest logger and not straight to stdout.

Various canned ent meta types always return a valid pointer (no more nils). This allows us to blindly deref + assign in various places.

Update ACL index tracking to ensure oss -> ent upgrades will work as expected.

Update ent meta parsing to include function to disallow wildcarding.
2019-12-06 14:01:34 -05:00
Freddy 60f6ec0c2f
Store check type in catalog (#6561) 2019-10-17 20:33:11 +02:00
R.B. Boyer 9566df524e
agent: cache notifications work after error if the underlying RPC returns index=1 (#6547)
Fixes #6521

Ensure that initial failures to fetch an agent cache entry using the
notify API where the underlying RPC returns a synthetic index of 1
correctly recovers when those RPCs resume working.

The bug in the Cache.notifyBlockingQuery used to incorrectly "fix" the
index for the next query from 0 to 1 for all queries, when it should
have not done so for queries that errored.

Also fixed some things that made debugging difficult:

- config entry read/list endpoints send back QueryMeta headers
- xds event loops don't swallow the cache notification errors
2019-09-26 10:42:17 -05:00
Freddy fdd10dd8b8
Expose HTTP-based paths through Connect proxy (#6446)
Fixes: #5396

This PR adds a proxy configuration stanza called expose. These flags register
listeners in Connect sidecar proxies to allow requests to specific HTTP paths from outside of the node. This allows services to protect themselves by only
listening on the loopback interface, while still accepting traffic from non
Connect-enabled services.

Under expose there is a boolean checks flag that would automatically expose all
registered HTTP and gRPC check paths.

This stanza also accepts a paths list to expose individual paths. The primary
use case for this functionality would be to expose paths for third parties like
Prometheus or the kubelet.

Listeners for requests to exposed paths are be configured dynamically at run
time. Any time a proxy, or check can be registered, a listener can also be
created.

In this initial implementation requests to these paths are not
authenticated/encrypted.
2019-09-25 20:55:52 -06:00
R.B. Boyer 5882e21b2b
agent: tolerate more failure scenarios during service registration with central config enabled (#6472)
Also:

* Finished threading replaceExistingChecks setting (from GH-4905)
  through service manager.

* Respected the original configSource value that was used to register a
  service or a check when restoring persisted data.

* Run several existing tests with and without central config enabled
  (not exhaustive yet).

* Switch to ioutil.ReadFile for all types of agent persistence.
2019-09-24 10:04:48 -05:00
R.B. Boyer f9496dc627 sdk: add freelist tracking and ephemeral port range skipping to freeport
This should cut down on test flakiness.

Problems handled:

- If you had enough parallel test cases running, the former circular
approach to handling the port block could hand out the same port to
multiple cases before they each had a chance to bind them, leading to
one of the two tests to fail.

- The freeport library would allocate out of the ephemeral port range.
This has been corrected for Linux (which should cover CI).

- The library now waits until a formerly-in-use port is verified to be
free before putting it back into circulation.
2019-09-17 14:30:43 -05:00
Sarah Adams 001137e5e5
test: ensure all TestAgent constructions use a constructor (#6443)
ensure all TestAgent constructions use a constructor to get start retries + test logs going to the right place

Fixes #6435
2019-09-05 10:24:36 -07:00
Sarah Adams 74461406e0
remove funky panic/recover in agent tests (#6442) 2019-09-04 13:59:11 -07:00
Sarah Adams 4ed5515fca
refactor & add better retry logic to NewTestAgent (#6363)
Fixes #6361
2019-09-03 15:05:51 -07:00
Mike Morris 65be58703c
connect: remove managed proxies (#6220)
* connect: remove managed proxies implementation and all supporting config options and structs

* connect: remove deprecated ProxyDestination

* command: remove CONNECT_PROXY_TOKEN env var

* agent: remove entire proxyprocess proxy manager

* test: remove all managed proxy tests

* test: remove irrelevant managed proxy note from TestService_ServerTLSConfig

* test: update ContentHash to reflect managed proxy removal

* test: remove deprecated ProxyDestination test

* telemetry: remove managed proxy note

* http: remove /v1/agent/connect/proxy endpoint

* ci: remove deprecated test exclusion

* website: update managed proxies deprecation page to note removal

* website: remove managed proxy configuration API docs

* website: remove managed proxy note from built-in proxy config

* website: add note on removing proxy subdirectory of data_dir
2019-08-09 15:19:30 -04:00
Paul Banks f38da47c55
Allow raft TrailingLogs to be configured. (#6186)
This fixes pathological cases where the write throughput and snapshot size are both so large that more than 10k log entries are written in the time it takes to restore the snapshot from disk. In this case followers that restart can never catch up with leader replication again and enter a loop of constantly downloading a full snapshot and restoring it only to find that snapshot is already out of date and the leader has truncated its logs so a new snapshot is sent etc.

In general if you need to adjust this, you are probably abusing Consul for purposes outside its design envelope and should reconsider your usage to reduce data size and/or write volume.
2019-07-23 15:19:57 +01:00
R.B. Boyer b16d7f00bc
agent: avoid reverting any check updates that occur while a service is being added or the config is reloaded (#6144) 2019-07-17 14:06:50 -05:00
Hans Hasselberg 33a7df3330
tls: auto_encrypt enables automatic RPC cert provisioning for consul clients (#5597) 2019-06-27 22:22:07 +02:00
Pierre Souchay 0e907f5aa8 Support for maximum size for Output of checks (#5233)
* Support for maximum size for Output of checks

This PR allows users to limit the size of output produced by checks at the agent 
and check level.

When set at the agent level, it will limit the output for all checks monitored
by the agent.

When set at the check level, it can override the agent max for a specific check but
only if it is lower than the agent max.

Default value is 4k, and input must be at least 1.
2019-06-26 09:43:25 -06:00
R.B. Boyer 40336fd353
agent: fix several data races and bugs related to node-local alias checks (#5876)
The observed bug was that a full restart of a consul datacenter (servers
and clients) in conjunction with a restart of a connect-flavored
application with bring-your-own-service-registration logic would very
frequently cause the envoy sidecar service check to never reflect the
aliased service.

Over the course of investigation several bugs and unfortunate
interactions were corrected:

(1)

local.CheckState objects were only shallow copied, but the key piece of
data that gets read and updated is one of the things not copied (the
underlying Check with a Status field). When the stock code was run with
the race detector enabled this highly-relevant-to-the-test-scenario field
was found to be racy.

Changes:

 a) update the existing Clone method to include the Check field
 b) copy-on-write when those fields need to change rather than
    incrementally updating them in place.

This made the observed behavior occur slightly less often.

(2)

If anything about how the runLocal method for node-local alias check
logic was ever flawed, there was no fallback option. Those checks are
purely edge-triggered and failure to properly notice a single edge
transition would leave the alias check incorrect until the next flap of
the aliased check.

The change was to introduce a fallback timer to act as a control loop to
double check the alias check matches the aliased check every minute
(borrowing the duration from the non-local alias check logic body).

This made the observed behavior eventually go away when it did occur.

(3)

Originally I thought there were two main actions involved in the data race:

A. The act of adding the original check (from disk recovery) and its
   first health evaluation.

B. The act of the HTTP API requests coming in and resetting the local
   state when re-registering the same services and checks.

It took awhile for me to realize that there's a third action at work:

C. The goroutines associated with the original check and the later
   checks.

The actual sequence of actions that was causing the bad behavior was
that the API actions result in the original check to be removed and
re-added _without waiting for the original goroutine to terminate_. This
means for brief windows of time during check definition edits there are
two goroutines that can be sending updates for the alias check status.

In extremely unlikely scenarios the original goroutine sees the aliased
check start up in `critical` before being removed but does not get the
notification about the nearly immediate update of that check to
`passing`.

This is interlaced wit the new goroutine coming up, initializing its
base case to `passing` from the current state and then listening for new
notifications of edge triggers.

If the original goroutine "finishes" its update, it then commits one
more write into the local state of `critical` and exits leaving the
alias check no longer reflecting the underlying check.

The correction here is to enforce that the old goroutines must terminate
before spawning the new one for alias checks.
2019-05-24 13:36:56 -05:00
Alvin Huang f45e495e38
Merge pull request #5376 from hashicorp/fix-tests
Fix tests in prep for CircleCI Migration
2019-04-04 17:09:32 -04:00
Jeff Mitchell 4243c3ae42
Move internal/ to sdk/ (#5568)
* Move internal/ to sdk/

* Add a readme to the SDK folder
2019-03-27 08:54:56 -04:00
Jeff Mitchell 47c390025b
Convert to Go Modules (#5517)
* First conversion

* Use serf 0.8.2 tag and associated updated deps

* * Move freeport and testutil into internal/

* Make internal/ its own module

* Update imports

* Add replace statements so API and normal Consul code are
self-referencing for ease of development

* Adapt to newer goe/values

* Bump to new cleanhttp

* Fix ban nonprintable chars test

* Update lock bad args test

The error message when the duration cannot be parsed changed in Go 1.12
(ae0c435877d3aacb9af5e706c40f9dddde5d3e67). This updates that test.

* Update another test as well

* Bump travis

* Bump circleci

* Bump go-discover and godo to get rid of launchpad dep

* Bump dockerfile go version

* fix tar command

* Bump go-cleanhttp
2019-03-26 17:04:58 -04:00
Hans Hasselberg e7134a0dab
agent: only use TestAgent when appropriate (#5502) 2019-03-18 17:06:16 +01:00
Valentin Fritz 21f149de8b Fix checks removal when removing service (#5457)
Fix my recently discovered issue described here: #5456
2019-03-14 11:02:49 -04:00
Hans Hasselberg 7e11dd82aa
agent: enable reloading of tls config (#5419)
This PR introduces reloading tls configuration. Consul will now be able to reload the TLS configuration which previously required a restart. It is not yet possible to turn TLS ON or OFF with these changes. Only when TLS is already turned on, the configuration can be reloaded. Most importantly the certificates and CAs.
2019-03-13 10:29:06 +01:00
Aestek 2aac4d5168 Register and deregisters services and their checks atomically in the local state (#5012)
Prevent race between register and deregister requests by saving them
together in the local state on registration.
Also adds more cleaning in case of failure when registering services
/ checks.
2019-03-04 09:34:05 -05:00
Matt Keeler 118adbb123
ACL Token Persistence and Reloading (#5328)
This PR adds two features which will be useful for operators when ACLs are in use.

1. Tokens set in configuration files are now reloadable.
2. If `acl.enable_token_persistence` is set to `true` in the configuration, tokens set via the `v1/agent/token` endpoint are now persisted to disk and loaded when the agent starts (or during configuration reload)

Note that token persistence is opt-in so our users who do not want tokens on the local disk will see no change.

Some other secondary changes:

* Refactored a bunch of places where the replication token is retrieved from the token store. This token isn't just for replicating ACLs and now it is named accordingly.
* Allowed better paths in the `v1/agent/token/` API. Instead of paths like: `v1/agent/token/acl_replication_token` the path can now be just `v1/agent/token/replication`. The old paths remain to be valid. 
* Added a couple new API functions to set tokens via the new paths. Deprecated the old ones and pointed to the new names. The names are also generally better and don't imply that what you are setting is for ACLs but rather are setting ACL tokens. There is a minor semantic difference there especially for the replication token as again, its no longer used only for ACL token/policy replication. The new functions will detect 404s and fallback to using the older token paths when talking to pre-1.4.3 agents.
* Docs updated to reflect the API additions and to show using the new endpoints.
* Updated the ACL CLI set-agent-tokens command to use the non-deprecated APIs.
2019-02-27 14:28:31 -05:00
Alvin Huang c2a19e5090 add wait to TestAgent_RPCPing 2019-02-22 17:34:45 -05:00
Matt Keeler 766d771017
Pass a testing.T into NewTestAgent and TestAgent.Start (#5342)
This way we can avoid unnecessary panics which cause other tests not to run.

This doesn't remove all the possibilities for panics causing other tests not to run, it just fixes the TestAgent
2019-02-14 10:59:14 -05:00
Matt Keeler acfd87c673
Improve Connect with Prepared Queries (#5291)
Given a query like:

```
{
   "Name": "tagged-connect-query",
   "Service": {
      "Service": "foo",
      "Tags": ["tag"],
      "Connect": true
   }
}
```

And a Consul configuration like:

```
{
   "services": [
      "name": "foo",
      "port": 8080,
      "connect": { "sidecar_service": {} },
      "tags": ["tag"]
   ]
}
```

If you executed the query it would always turn up with 0 results. This was because the sidecar service was being created without any tags. You could instead make your config look like:

```
{
   "services": [
      "name": "foo",
      "port": 8080,
      "connect": { "sidecar_service": {
         "tags": ["tag"]
      } },
      "tags": ["tag"]
   ]
}
```

However that is a bit redundant for most cases. This PR ensures that the tags and service meta of the parent service get copied to the sidecar service. If there are any tags or service meta set in the sidecar service definition then this copying does not take place. After the changes, the query will now return the expected results.

A second change was made to prepared queries in this PR which is to allow filtering on ServiceMeta just like we allow for filtering on NodeMeta.
2019-02-04 09:36:51 -05:00
Kyle Havlovitz 7118f42950
Fix failing TestAgent_PurgeCheckOnDuplicate after merge 2019-01-28 13:19:38 -08:00
Kyle Havlovitz 1a4978fb94
Re-add ReadableDuration types to health check definition
This is to fix the backwards-incompatible change made in 1.4.1 by
changing these fields to time.Duration.
2019-01-25 14:47:35 -08:00
Paul Banks bb7145f27d
agent: add default weights to service in local state to prevent AE churn (#5126)
* Add default weights when adding a service with no weights to local state to prevent constant AE re-sync.

This fix was contributed by @42wim in https://github.com/hashicorp/consul/pull/5096 but was merged against the wrong base. This adds it to master and adds a test to cover the behaviour.

* Fix tests that broke due to comparing internal state which now has default weights
2019-01-08 10:13:49 +00:00
Aestek 8709213d6e Prevent status flap when re-registering a check (#4904)
Fixes point `#2` of: https://github.com/hashicorp/consul/issues/4903

When registering a service each healthcheck status is saved and restored (https://github.com/hashicorp/consul/blob/master/agent/agent.go#L1914) to avoid unnecessary flaps in health state.
This change extends this feature to single check registration by moving this protection in `AddCheck()` so that both `PUT /v1/agent/service/register` and `PUT /v1/agent/check/register` behave in the same idempotent way.

#### Steps to reproduce
1. Register a check :
```
curl -X PUT \
  http://127.0.0.1:8500/v1/agent/check/register \
  -H 'Content-Type: application/json' \
  -d '{
  "Name": "my_check",
  "ServiceID": "srv",
  "Interval": "10s",
  "Args": ["true"]
}'
```
2. The check will initialize and change to `passing`
3. Run the same request again
4. The check status will quickly go from `critical` to `passing` (the delay for this transission is determined by https://github.com/hashicorp/consul/blob/master/agent/checks/check.go#L95)
2019-01-07 13:53:03 -05:00
Aestek 25f04fbd21 [Security] Add finer control over script checks (#4715)
* Add -enable-local-script-checks options

These options allow for a finer control over when script checks are enabled by
giving the option to only allow them when they are declared from the local
file system.

* Add documentation for the new option

* Nitpick doc wording
2018-10-11 13:22:11 +01:00