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https://issues.apache.org/jira/browse/TS-4299?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Leif Hedstrom updated TS-4299:
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Fix Version/s: 6.1.2
> FetchSM / H2 streams can hang if e.g. a plugin adds a Connection: close header
> ------------------------------------------------------------------------------
>
> Key: TS-4299
> URL: https://issues.apache.org/jira/browse/TS-4299
> Project: Traffic Server
> Issue Type: Bug
> Components: Core, HTTP/2
> Reporter: Leif Hedstrom
> Assignee: Leif Hedstrom
> Fix For: 6.1.2, 6.2.0
>
>
> We use header_rewrite to inject Connection: close under certain conditions
> (to prevent KA connections from lingering forever during e.g. server
> maintenance). However, this interacts poorly with the FetchSM, and therefore,
> poorly with H2. Basically, the connection "hangs" because the FetchSM thinks
> there's more body data (when there really isn't).
> The issue comes from this code:
> {code}
> bool
> FetchSM::has_body()
> {
> int status_code;
> HTTPHdr *hdr;
> if (!header_done)
> return false;
> if (is_method_head)
> return false;
> //
> // The following code comply with HTTP/1.1:
> // http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.4
> //
> hdr = &client_response_hdr;
> status_code = hdr->status_get();
> if (status_code < 200 || status_code == 204 || status_code == 304)
> return false;
> if (check_chunked())
> return true;
> if (check_connection_close())
> return true;
> resp_content_length = hdr->value_get_int64(MIME_FIELD_CONTENT_LENGTH,
> MIME_LEN_CONTENT_LENGTH);
> if (!resp_content_length)
> return false;
> return true;
> }
> {code}
> The issue is that it returns "true" if there is a Connection: close header.
> I'm not 100% sure what the best solution here, simply removing this doesn't
> seem right since it's obviously there to deal with some cases of FetchSM
> which are not H2. A couple of unscientific options are
> 1) Make sure the H2 code assures that the Connection header is removed in all
> cases. I know it deals with it in a few cases, except in this case we add the
> Connection: close in the response header object, which therefore enters into
> the FetchSM as well.
> 2) Have additional state / information in the FetchSM, indicating if
> "connection" has semantics or not for this particular FetchSM. E.g.
> fetch_sm->set_connection_aware(false);
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