c-ares: add option for udp_max_queries #33551

deveshkandpal1224 · 2024-04-16T06:49:27Z

Commit Message: Provides an option to set udp_max_queries in DNSResolverOptions to limit max UDP queries.
Additional Description: This change does following:

Implements the fix in this version of c-ares library that has been raised in this comment.
Updates cares_dns_resolver.proto to expose the option to pass udp_max_queries which can then be passed to c-ares.
Adds a unit test to validate that when udp_max_queries is set, ARES_OPT_UDP_MAX_QUERIES flag is set as well.

Risk Level: Low
Testing: Unit test
Docs Changes: n/a
Release Notes: updated
Platform Specific Features:
[Optional Runtime guard:]
[Optional Fixes #Issue]
[Optional Fixes commit #PR or SHA]
[Optional Deprecated:]
[Optional API Considerations:]

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

repokitteh-read-only · 2024-04-16T06:49:39Z

CC @envoyproxy/api-shepherds: Your approval is needed for changes made to (api/envoy/|docs/root/api-docs/).
envoyproxy/api-shepherds assignee is @lizan
CC @envoyproxy/api-watchers: FYI only for changes made to (api/envoy/|docs/root/api-docs/).
CC @envoyproxy/dependency-shepherds: Your approval is needed for changes made to (bazel/.*repos.*\.bzl)|(bazel/dependency_imports\.bzl)|(api/bazel/.*\.bzl)|(.*/requirements\.txt)|(.*\.patch).
envoyproxy/dependency-shepherds assignee is @htuch

🐱

Caused by: #33551 was opened by deveshkandpal1224.

see: more, trace.

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

adisuissa · 2024-04-16T13:21:59Z

@yanjunxiang-google can you please take a first pass?

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

yanjunxiang-google · 2024-04-16T19:27:26Z

source/extensions/network/dns_resolver/cares/dns_impl.cc

@@ -194,7 +202,7 @@ void DnsResolverImpl::AddrInfoPendingResolution::onAresGetAddrInfoCallback(
    //
    // The channel cannot be destroyed and reinitialized here because that leads to a c-ares
    // segfault.
-    if (status == ARES_ECONNREFUSED) {
+    if (status == ARES_ECONNREFUSED || status == ARES_EREFUSED) {


nit: This change is for updating c-ares library to 1.20, but have nothing to do with the udp_max_queries option support. Does it make sense to separate it?

DestroyChannelOnRefused and CustomResolverValidAfterChannelDestruction test fail in dns_impl_test.cc after upgrading the c-ares library to 1.20 if this isn't added, while udp_max_queries is supported in 1.20 so kind of tied together if that makes sense ? Or do you suggest splitting this into 2 PRs ?

Can you split into two PRs? It will make it easier to review the dependency updates vs. the UDP query specific change proposed. Thanks!

sure I can split it. Let me send out a PR for library update.

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

yanjunxiang-google · 2024-04-16T19:36:00Z

test/extensions/network/dns_resolver/cares/dns_impl_test.cc

+
+// Validate that c_ares flag `ARES_OPT_UDP_MAX_QUERIES` is set when UInt32 property
+// `udp_max_queries` is set.
+TEST_P(DnsImplAresFlagsForMaxUdpQueriesinTest, UdpMaxQueriesIsSet) {


nit:
Is there a way to verify the UdpMaxQueries number actually is enforced by the c-ares library?

@yanjunxiang-google - do you mean by checking opts.udp_max_queries or something more involved ? I tried poking in that area but couldn't find anything obvious - if you have suggestions - happy to look into it!

I was pushing c'ares team for this change : c-ares/c-ares#444

I believe you can test like this:

set this value as n

keep pumping traffic.

Dont turn on dns over tcp

Sniffing ('ngrep -W single -l -q -d any -i "" udp port 53') the DNS packets

The src port should keep changing after every n DNS resolution requests.

This change should be ok as is, since we rely on c-ares to test the behavior of the ARES_OPT_UDP_MAX_QUERIES flag. I do not think it is important to validate that this flag is working in c-ares.

yanjunxiang-google · 2024-04-16T19:36:38Z

LGTM in high level except a few nit comments.

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

yanjunxiang-google · 2024-04-18T15:24:50Z

LGTM

lizan · 2024-04-18T16:31:08Z

/lgtm api

@yanavlasov for cares DNS resolver owner.

rakeshdatta

I was pushing c'ares team for this change : c-ares/c-ares#444

I believe you can test like this:

set this value as n
keep pumping traffic.
Dont turn on dns over tcp
Sniffing ('ngrep -W single -l -q -d any -i "" udp port 53') the DNS packets

The src port should keep changing after every n DNS resolution requests.

yanavlasov

/wait-any

yanavlasov · 2024-04-22T17:28:28Z

api/envoy/config/core/v3/resolver.proto

+
+  // This option allows for number of UDP based DNS queries to be capped. Note, this
+  // is only applicable to c-ares DNS resolver currently.
+  google.protobuf.UInt32Value udp_max_queries = 3;


Would it make sense to move this option in c-ares specific configuration: https://github.com/envoyproxy/envoy/blob/main/api/envoy/extensions/network/dns_resolver/cares/v3/cares_dns_resolver.proto ?

I was in two minds thinking that if tomorrow there was an option for apple dns resolver, it could be leveraged. But happy to move this to c-ares if that makes more sense.

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

c-ares: add option for udp_max_queries

ae8bd25

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

deveshkandpal1224 requested review from yanavlasov and mattklein123 as code owners April 16, 2024 06:49

repokitteh-read-only bot added api deps Approval required for changes to Envoy's external dependencies labels Apr 16, 2024

repokitteh-read-only bot assigned lizan and htuch Apr 16, 2024

resolve conflicts

79ef702

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

deveshkandpal1224 added 2 commits April 16, 2024 11:03

fix whitespace

2e40135

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fix line length issue

b97ad5a

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yanjunxiang-google reviewed Apr 16, 2024

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fix current.yaml for doc update

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yanjunxiang-google reviewed Apr 16, 2024

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deveshkandpal1224 added 4 commits April 16, 2024 23:14

fix segfault in unit test

35d6a19

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

resolve conflict

5f0625a

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

fix format

3a117a9

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

add test for udp_max_queries

bc4470c

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

repokitteh-read-only bot removed the api label Apr 18, 2024

lizan assigned yanavlasov and unassigned lizan Apr 18, 2024

rakeshdatta reviewed Apr 18, 2024

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deveshkandpal1224 mentioned this pull request Apr 22, 2024

c-ares: upgrade library to 1.20.1 #33711

Merged

yanavlasov reviewed Apr 22, 2024

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repokitteh-read-only bot added the waiting:any label Apr 22, 2024

ramaraochavali mentioned this pull request Apr 24, 2024

DNS resolution failure results in UH / no healthy upstream #31992

Closed

repokitteh-read-only bot removed waiting:any labels Apr 26, 2024

deveshkandpal1224 added 2 commits April 27, 2024 22:44

fix merge conflicts

973c8ae

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

move udp_max_queries to cares

b59d5dc

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

repokitteh-read-only bot added the api label Apr 28, 2024

deveshkandpal1224 added 3 commits April 28, 2024 16:54

refactor and fix test

5da6454

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

fix current.yaml

f97933a

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

update api ref

392cc7e

Signed-off-by: deveshkandpal1224 <deveshkandpal1224@gmail.com>

yanavlasov approved these changes Apr 29, 2024

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yanavlasov merged commit 048d9a2 into envoyproxy:main Apr 29, 2024
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deveshkandpal1224 deleted the devesh24/upgrade-c-ares branch April 29, 2024 17:10

agrawroh mentioned this pull request Aug 1, 2024

Increased DNS Timeouts After Upgrading to v1.31.0 #35117

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c-ares: add option for udp_max_queries #33551

c-ares: add option for udp_max_queries #33551

deveshkandpal1224 commented Apr 16, 2024 •

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deveshkandpal1224 Apr 26, 2024

c-ares: add option for udp_max_queries #33551

c-ares: add option for udp_max_queries #33551

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