QUIC: add error code for handshake failed.

[Sergey Kandaurov]

> On 22 Feb 2023, at 17:15, Roman Arutyunyan <arut at nginx.com> wrote:
> 
> On Tue, Feb 21, 2023 at 05:54:42PM +0400, Sergey Kandaurov wrote:
> 
> [..]
> 
>> # HG changeset patch
>> # User Sergey Kandaurov <pluknet at nginx.com>
>> # Date 1676987626 -14400
>> #      Tue Feb 21 17:53:46 2023 +0400
>> # Branch quic
>> # Node ID e012c3999592fc935bfc786a232903567c512bfe
>> # Parent  baada8d864cbedc7557b879f89eee5c412f3ca85
>> QUIC: moved "handshake failed" reason to send_alert.
>> 
>> A QUIC handshake may fail for a variety of reasons, which breaks down into
>> several cases, in order of precedence:
> 
>> - generally, the error code is reported with the send_alert callback
>> - else, our own QUIC checks may set specific error code / reason phrase
>> - as a last resort, handshake may fail for some reason, which falls back
>>  to send INTERNAL_ERROR in the CONNECTION_CLOSE frame.
>> Now, in the first case, both error code and generic phrase are set in the
>> send_alert callback, to preserve a specific reason phrase from overriding.
>> Additionally, absent error code / reason phrase are now converted to just
>> INTERNAL_ERROR, without reason phrase set.
> i>
>> Reported by Jiuzhou Cui.
> 
> I suggest the following commit message:
> 
> QUIC: moved "handshake failed" reason to send_alert.
> 
> A QUIC handshake may fail for a variety of reasons, which breaks down into
> several cases, in order of precedence:
> 
> - a handshake error which leads to a send_alert call
> - an error triggered by add_handshake_data callback
> - internal errors (allocation etc)
> 
> Previously, in the first case, only error code was set in send_alert callback.
> Now "handshake failed" is set there as a reason.  In the second case, error
> code and reason are set by add_handshake_data.  In the last case, setting
> error reason is now removed.  Returning NGX_ERROR will lead to closing the
> connection with just INTERNAL_ERROR.
> 
> Reported by Jiuzhou Cui.

Thanks, applied with minor adjustments.

https://hg.nginx.org/nginx-quic/rev/cb7dc35ed428

-- 
Sergey Kandaurov