net/http: HTTP/2 SETTINGS frame being read incorrectly

[x04]

What version of Go are you using (go version)?

$ go version
go version go1.14beta1 windows/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=on
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\\AppData\Local\go-build
set GOENV=C:\Users\\AppData\Roaming\go\env
set GOEXE=.exe
set GOFLAGS= -mod=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\\go
set GOPRIVATE=
set GOPROXY=direct
set GOROOT=C:\Users\\go\go1.14beta1
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Users\\go\go1.14beta1\pkg\tool\windows_amd64
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=C:\Users\\go\go1.14beta1\src\go.mod
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\\AppData\Local\Temp\go-build787882606=/tmp/go-build -gno-record-gcc-switches

What did you do?

I outputted all HTTP/2 frames that are received by the net/http server corresponding to their type, and when looking at the SETTINGS frames the first settings ID always appears to be wrong.

For example, the first setting from Chrome is 0x1 or SETTINGS_HEADER_TABLE_SIZE, but the ID outputted by when looping through the settings in the frame is 239 when the expected value is 1.

Another example would be when I used Go's http.Client and the first setting is always 0x2 or SETTINGS_ENABLE_PUSH, but the outputted value 16384 when the expected value is 2.

What did you expect to see?

(Read above for explanation on what I'm talking about)
Expected first setting ID from latest Chrome: 1, SETTINGS_HEADER_TABLE_SIZE
Expected first setting ID from Go's http client: 2, SETTINGS_ENABLE_PUSH

What did you see instead?

(Read above for explanation on what I'm talking about)
"Received" first setting ID from latest Chrome: 239
"Received" first setting ID from Go's http client: 16384

[dmitshur]

@x04 Do you know if this happens with Go 1.13 or 1.12 too?

/cc @bradfitz per owners.

[networkimprov]

cc @fraenkel re http2

[fraenkel]

@x04 is there a reproducer? Can you run with http2debug so we can see what is being processed?

[bradfitz]

I don't understand the bug report.

Let's see some code and GODEBUG=http2debug=2 log output first as @fraenkel suggested.

[gopherbot]

Timed out in state WaitingForInfo. Closing.

(I am just a bot, though. Please speak up if this is a mistake or you have the requested information.)