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Opened 8 months ago

Last modified 5 months ago

#2587 assigned defect

can't peek at some http traffic

Reported by: Antoine Martin Owned by: Antoine Martin
Priority: critical Milestone: 4.1
Component: html5 Version: 3.0.x
Keywords: Cc:


Fedora 31 server running trunk (v4).

Instead of detecting the http traffic, peek returns no data and we fail with:

io_in_cb(<socket.socket fd=4, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('', 10000)>, <flags G_IO_IN of type GLib.IOCondition>)
socket tcp socket: <- peek: got 0 bytes
may_wrap_socket: no data, not wrapping
New tcp connection received
 from ''
 on ''

That's despite waiting for 1 second polling the socket...

wireshark shows that the TCP packet does contain the HTTP GET request:

GET / HTTP/1.1
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Save-Data: on
User-Agent: Mozilla/5.0 (Linux; Android 10; PH-1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.87 Mobile Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: en-GB,en;q=0.9,fr-FR;q=0.8,fr;q=0.7,th-TH;q=0.6,th;q=0.5,en-US;q=0.4

This happens with android clients, but not with desktop browsers!?

Attachments (2)

peekable.patch (1.6 KB) - added by Antoine Martin 7 months ago.
make all sockets peekable
websocket-failure.pcapng (2.1 KB) - added by Antoine Martin 6 months ago.
wireshark capture of a failure

Download all attachments as: .zip

Change History (7)

comment:1 Changed 7 months ago by Antoine Martin

Status: newassigned

Adding a recv call immediately after the empty peek shows that the data is there waiting to be read!?

comment:2 Changed 7 months ago by Antoine Martin

This is a kernel / distro bug.
Every other distro works just fine. Tested: Ubuntu 18.04, Ubuntu 19.10, Debian Stretch, Debian Buster, etc..

The problem only occurs on Fedora 30 and 31. (Not tested Fedora 29 or earlier).
And also with MS Windows servers!

Last edited 7 months ago by Antoine Martin (previous) (diff)

comment:3 Changed 7 months ago by Antoine Martin

Things I've tried:

  • disabling and forcing nodelay / cork
  • increasing the peek timeout
  • different router, different network interface

Wireshark shows:

  • client -> server: SYN
  • server -> client: SYN+ACK
  • client -> server: "GET /"
  • server -> client: RST

Why do we reset the connection!? We're actually doing a recv when that happens!?

Also happens with v3.

Changed 7 months ago by Antoine Martin

Attachment: peekable.patch added

make all sockets peekable

comment:4 Changed 7 months ago by Antoine Martin

The patch above uses the same workaround that is used with ssl sockets: emulate peek by actually reading from the socket (without PEEK) but cache the data and return it later. (also uncomment enable_peek() to use it)
Does not always help. No idea why.

Last edited 7 months ago by Antoine Martin (previous) (diff)

Changed 6 months ago by Antoine Martin

Attachment: websocket-failure.pcapng added

wireshark capture of a failure

comment:5 Changed 5 months ago by Antoine Martin

Milestone: 4.04.1
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