Package: trickle
Version: 1.07-10
Severity: normal
Dear Maintainer,
At the top of 'trickle's reimplementation of socket() in the file
trickle-overload.c it has a check that includes 'type == SOCK_STREAM', so that
only connections of type SOCK_STREAM are eligible for processing.
Some programs open the socket with 'type = SOCK_STREAM | SOCK_CLOEXEC'. The
`SOCK_CLOEXEC` is a Linux extension (since 2.6.27) that avoids the use of a
subsequent fcntl() call to set the close-on-exec flag.
Unfortunately 'SOCK_STREAM' is not the same as 'SOCK_STREAM | SOCK_CLOEXEC' so
the 'trickle' processing will not take place.
You can see the effect with this sample ruby code, where the download is not
restricted in any way.
cat >test.rb <<x
require 'net/http'
Net::HTTP.get_response(URI.parse("http://download.thinkbroadband.com/50MB.zip";))
x
trickle -s -d 10 ruby test.rb
Running 'strace -e trace=socket ruby test.rb' clearly shows the socket() calls
with 'SOCK_STREAM | SOCK_CLOEXEC'.
I can't see any #define available in sys/socket.h that can be used to mask out
the socket type from the extension fields, but 0x4ff could work (for now). Or
you could mask out (SOCK_NONBLOCK | SOCK_CLOEXEC) from the type before checking
that it's SOCK_STREAM. But maybe there's a better way.
-- System Information:
Debian Release: stretch/sid
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.5.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages trickle depends on:
ii libbsd0 0.8.3-1
ii libc6 2.22-7
ii libevent-2.0-5 2.0.21-stable-2+b1
trickle recommends no packages.
trickle suggests no packages.
-- no debconf information
