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Opened 10 months ago

Closed 7 weeks ago

#2587 closed defect (fixed)

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:

Description

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=('0.0.0.0', 10000)>, <flags G_IO_IN of type GLib.IOCondition>)
(..)
socket tcp socket: 192.168.0.10:10000 <- 192.168.0.106:47438 peek: got 0 bytes
may_wrap_socket: no data, not wrapping
(..)
New tcp connection received
 from '192.168.0.106:47438'
 on '0.0.0.0:10000'

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
Host: 192.168.0.10:10000
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 (3)

peekable.patch (1.6 KB) - added by Antoine Martin 10 months ago.
make all sockets peekable
websocket-failure.pcapng (2.1 KB) - added by Antoine Martin 9 months ago.
wireshark capture of a failure
peekable-v2.patch (1.6 KB) - added by Antoine Martin 7 weeks ago.
updated patch

Download all attachments as: .zip

Change History (9)

comment:1 Changed 10 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 10 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 10 months ago by Antoine Martin (previous) (diff)

comment:3 Changed 10 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 10 months ago by Antoine Martin

Attachment: peekable.patch added

make all sockets peekable

comment:4 Changed 10 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 10 months ago by Antoine Martin (previous) (diff)

Changed 9 months ago by Antoine Martin

Attachment: websocket-failure.pcapng added

wireshark capture of a failure

comment:5 Changed 7 months ago by Antoine Martin

Milestone: 4.04.1

Changed 7 weeks ago by Antoine Martin

Attachment: peekable-v2.patch added

updated patch

comment:6 Changed 7 weeks ago by Antoine Martin

Resolution: fixed
Status: assignedclosed

r27660 logs more details of connection timeouts.

I really don't understand why this makes any difference, but r27662 fixes things.
(at least I haven't been able to reproduce the bug with the Android tablet or mswindows browsers)

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