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Ville Vesilehto 0d8cbb1a6b Merge commit from fork

Add configurable resource limits to prevent potential DoS vectors
via connection/stream exhaustion on gRPC, HTTPS, and HTTPS/3 servers.

New configuration plugins:
- grpc_server: configure max_streams, max_connections
- https: configure max_connections
- https3: configure max_streams

Changes:
- Use netutil.LimitListener for connection limiting
- Use gRPC MaxConcurrentStreams and message size limits
- Add QUIC MaxIncomingStreams for HTTPS/3 stream limiting
- Set secure defaults: 256 max streams, 200 max connections
- Setting any limit to 0 means unbounded/fallback to previous impl

Defaults are applied automatically when plugins are omitted from
config.

Includes tests and integration tests.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

2025-12-17 19:08:59 -08:00

README.md

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2025-12-17 19:08:59 -08:00

setup_test.go

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setup.go

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README.md

https3

Name

https3 - configures DNS-over-HTTPS/3 (DoH3) server options.

Description

The https3 plugin allows you to configure parameters for the DNS-over-HTTPS/3 (DoH3) server to fine-tune the security posture and performance of the server. HTTPS/3 uses QUIC as the underlying transport.

This plugin can only be used once per HTTPS3 listener block.

Syntax

https3 {
    max_streams POSITIVE_INTEGER
}

max_streams limits the number of concurrent QUIC streams per connection. This helps prevent unbounded streams on a single connection, exhausting server resources. The default value is 256 if not specified. Set to 0 to use underlying QUIC transport default.

Examples

Set custom limits for maximum streams:

https3://.:443 {
    tls cert.pem key.pem
    https3 {
        max_streams 50
    }
    whoami
}

Set values to 0 for QUIC transport default, matching CoreDNS behaviour before v1.14.0:

https3://.:443 {
    tls cert.pem key.pem
    https3 {
        max_streams 0
    }
    whoami
}