Permanent error on AAAA request

[pavlyuts]

What is Happening / What is expected

DPS logs fault, associated to AAAA request on container name
Log entry:

Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]: 08:28:44.878 [Thread-41      ] WAR c.m.d.server.dns.RequestHandlerDefault            l=93   m=solve0                          status=solverFailed, currentSolverTime=8, totalTime=8, solver=SolverDocker, query=query=AAAA:db.docker, eClass=NullPointerException, msg=null
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]: java.lang.NullPointerException: null
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.Objects.requireNonNull(Objects.java:233)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.Optional.of(Optional.java:113)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:194)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:191)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:647)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.docker.ContainerSolvingService.findBestMatch(ContainerSolvingService.java:50)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.SolverDocker.lambda$handle$0(SolverDocker.java:40)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.HostnameMatcher.match(HostnameMatcher.java:22)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.SolverDocker.handle(SolverDocker.java:39)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.RequestHandlerDefault.solve0(RequestHandlerDefault.java:75)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.SolverCache.lambda$handleRes$0(SolverCache.java:38)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.commons.caching.LruTTLCache.lambda$computeIfAbsentWithTTL$1(LruTTLCache.java:94)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.ConcurrentHashMap.compute(ConcurrentHashMap.java:1916)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.commons.caching.LruTTLCache.lambda$computeIfAbsentWithTTL$2(LruTTLCache.java:88)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.ConcurrentHashMap.compute(ConcurrentHashMap.java:1916)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.commons.caching.LruTTLCache.computeIfAbsentWithTTL(LruTTLCache.java:86)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.SolverCache.handleRes(SolverCache.java:36)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.solver.SolverCache.handle(SolverCache.java:31)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.RequestHandlerDefault.solve(RequestHandlerDefault.java:51)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.RequestHandlerDefault.handle(RequestHandlerDefault.java:42)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.UDPServer.handle(UDPServer.java:54)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at com.mageddo.dnsproxyserver.server.dns.UDPServer.lambda$start0$0(UDPServer.java:42)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:577)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.FutureTask.run(FutureTask.java:317)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at java.base@19.0.2/java.lang.Thread.run(Thread.java:1589)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at org.graalvm.nativeimage.builder/com.oracle.svm.core.thread.PlatformThreads.threadStartRoutine(PlatformThreads.java:775)
Dec 07 11:28:44 pavlyuts.ru dns-proxy-server[448]:         at org.graalvm.nativeimage.builder/com.oracle.svm.core.posix.thread.PosixPlatformThreads.pthreadStartRoutine(PosixPlatformThreads.java:203)

To reproduce:

1. Setup Docker
2. Setup DPS standaone mode and configure it
3. Create container with docker default network conection and name 'test'
4. dig @127.0.0.1 test.docker AAAA
5. Check DPS logs

DPS config file

{
  "version": 2,
  "remoteDnsServers": [ ],
  "envs": [
    {
      "name": "",
      "hostnames": [ ]
    }
  ],
  "activeEnv": "",
  "webServerPort": 5380,
  "dnsServerPort": 53,
  "logLevel": "INFO",
  "logFile": "console",
  "registerContainerNames": true,
  "domain": "docker",
  "dpsNetwork": false,
  "dpsNetworkAutoConnect": false,
  "defaultDns": false,
  "hostMachineHostname" : "host.docker",
  "serverProtocol": "UDP_TCP",
  "dockerHost": null,
  "resolvConfOverrideNameServers": false,
  "noRemoteServers": true,
  "noEntriesResponseCode": 3
}

Specs

• OS: Debian 11, Oracle Linux 8
• Docker Version: 24.0.7
• DPS Version: 3.15.13-snapshot

[sneusse]

same here, can we disable AAAA in some way?

[mageddo]

Hey thanks for the report.

I got this, the issue is caused when beyond the container, your hostmachine or the docker engine also hasn't an associated IPV6, it will try to use the host machine IPV6 but it hasn't one associated, null is returned:

ContainerSolvingService l=132 ...  status=noNetworkAvailable, usingHostMachineIp=null

Then the error occurs

18:23:47.453 [Thread-6       ] WAR c.m.d.server.dns.RequestHandlerDefault            l=93   m=solve0                          status=solverFailed, currentSolverTime=33, totalTime=33, solver=SolverDocker, query=query=AAAA:test.docker, eClass=NullPointerException, msg=null
java.lang.NullPointerException: null
        at java.base@19.0.2/java.util.Objects.requireNonNull(Objects.java:233)
        at java.base@19.0.2/java.util.Optional.of(Optional.java:113)
        at java.base@19.0.2/java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:194)
        at java.base@19.0.2/java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:191)
        at java.base@19.0.2/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
        at java.base@19.0.2/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base@19.0.2/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:647)
        at com.mageddo.dnsproxyserver.docker.ContainerSolvingService.findBestMatch(ContainerSolvingService.java:50)

update

The bug is here, .findFirst() will throw a NPE when there is a null value in the collection, which is the case, the host machine IP produced in .map is null.

dns-proxy-server/src/main/java/com/mageddo/dnsproxyserver/docker/ContainerSolvingService.java

Line 50 in 17b0c00

.findFirst()

I'm working on the fix

[mageddo]

same here, can we disable AAAA in some way?

No sure, it's related to your OS and DNS client, it's asking for AAAA records then DPS will answer them, so you have to disable the AAAA queries on the requester, don't know how.

[mageddo]

Just to make it clear, this issue won't make DPS stop of working, just will produce a lot of unnecessary logs