Client hangs when multiple requests are sent that exceed maxHeaderSize

[dilanSachi]

Description:
When a request that exceeds the maxHeaderSize is sent, it returns 431 successfully. However, when a second request that exceeds the header size is sent, client hangs. This is noticeable in gRPC and not noticeable in HTTP.

What happens is, when the server and client exchanges their settings via SETTINGS frames in the connection initialization, client gets to know the maxHeaderSize that is allowed by the server. In this instance, netty has a flag [1] to enable header size check before writing the headers to the network. When this results in an error, the transport implementation does not have a path to handle the error flow. One option is to enable the flag to not check the headers before sending the request. This way, server will check the header length and return with error.

Other option is to fix the error flow. I feel this is the most appropriate solution.

[1] https://github.com/netty/netty/blob/4.1/codec-http2/src/main/java/io/netty/handler/codec/http2/HpackEncoder.java#L121

[dilanSachi]

Update - This was noticed in http as well (2201.8.4).

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.