http3: only use :protocol pseudo-header for Extended CONNECT

[taoso]

The default value should be "HTTP/3.0".

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[marten-seemann]

Can you explain the motivation behind this PR?

[taoso]

Can you explain the motivation behind this PR?

hi @marten-seemann If the client fire a CONNECT request without :protocol, this req.Proto will be empty without this patch.

[marten-seemann]

I think this PR is correct, but I'd to tighten the validation logic here a bit. The :protocol pseudo header is only defined for Extended Connect requests (RFC 9220). We should reject any non-Extended Connected request that sets this header field.

@taoso Do you want to update the PR? We'd also need a test case that tests that we correctly reject requests with :protocol header.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a2cf43d) 84.06% compared to head (c437c54) 84.07%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4261      +/-   ##
==========================================
+ Coverage   84.06%   84.07%   +0.01%     
==========================================
  Files         150      150              
  Lines       15425    15424       -1     
==========================================
+ Hits        12966    12967       +1     
+ Misses       1955     1954       -1     
+ Partials      504      503       -1     

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[taoso]

Hi @marten-seemann , let me try.

[marten-seemann]

LGTM, thanks for pushing this through @taoso!

[taoso]

Hi @marten-seemann Could this PR be merged?