Reviewing the manpage for tmux indicated that SIGUSR1 can be sent to force the sockets to be recreated thus as my users I did the following:

$ killall -s SIGUSR1 tmux

Then I was able to reattach to the session. Further reading suggest that I must have updated my tmux whilst it was still running which is officially unsupported, so I was lucky!

In preparation for this, you will need to install yaourt and enable it with sudo access. Either that or replace all the references to yaourt below with pacman.

Drop this into your ~/.bashrc (or zshrc):

function arch() {
        if [ -z "$1" ]; then
                echo "arch  " >&2
                return -1
        fi

        case $1 in
                upgrade)
                        # Synchronize, upgrade
                        shift
                        sudo yaourt -Syu $@
                        ;;
                install)
                        # Install stuff
                        shift
                        sudo yaourt -S $@
                        ;;
                localinstall)
                        # Install file
                        shift
                        sudo yaourt -U $@
                        ;;
                remove)
                        # Remove
                        shift
                        sudo yaourt -R $@
                        ;;
                fullremove)
                        # Remove file
                        shift
                        sudo yaourt -Rns $@
                        ;;
                info)
                        # Display information
                        shift
                        yaourt -Si $@
                        ;;
                search)
                        # Search
                        shift
                        yaourt -Ss $@
                        ;;
        esac
}

Now you can do things like:

$ arch install git
$ arch remove git
$ arch info git
$ arch search git

Hope its handy!

ip_conntrack: table full, dropping packet

So my first thought it that it might relate to memory usage. Fortunately enough the kernel provides all the information we need to work it out. The kernel will allocate a “slab” when ever conntrack requires more memory, equally it will retain these slabs for a period of time and reuse if required. Each “slab” represents a number of pages of kernel memory, we can retrieve the current page size by using the following command:

# getconf PAGESIZE
4096

So each page is 4096 bytes. Next lets see how many slabs conntrack is using:

# grep conntrack /proc/slabinfo
ip_conntrack        6537  16620    384  984 1662    1 :  496  124

So that represents the following:

• ip_conntrack; a human readable name
• 6537; total number of objects in use.
• 16620; total available objects (including unused)
• 384; size of each object.
• 984; the number of slabs that are active
• 1662; the total number of slabs
• 1; the number of pages required to make a slab (normally 1)

The two other columns after the colon relate to SMP CPU information; we don’t need to discuss them.

So 6537 objects each of size 384 bytes, which means that we can fix around 10 per slab (4096/384=10.66). That means that the objects represent 2510208 bytes (~2.4Mb), but because of the overhead we are actually using 654 (6537/10=653.7) slabs or 2.6Mb (654*4096=2678784). So we are wasting around 256 bytes per slab (4096-384*10).

In other words an extremely small amount of memory. So it is very unlikely that is the cause. Further investigation reveal that it is normally due to the conntrack hitting the maximum count which can be viewed by looking at:

# cat /proc/sys/net/ipv4/ip_conntrack_max
65536

Comparing this to the current count:

#  wc -l ./proc/sys/net/ip_conntrack
   5602 /proc/net/ip_conntrack

We now know that it doesn’t use any great deal of memory at all, so we can easily double the count by doing the following:

# echo 131072 >/proc/sys/net/ipv4/ip_conntrack_max

Obviously in this example the memory usage was minor and there was little need to double the count but you can review your own system and increase as you wish now we know that it has a very small memory footprint.

A quick Google pointed me towards a post on the useful Add-On Mirrors site. I then went to the homepage of the author and installed the nice tool KeyConfig.

A quick restart of Firefox, then open KeyConfig (via Tools > KeyConfig), search for the Ctrl+q key press and disable.

Another restart of Firefox and it’s complete, no more accidental quits of Firefox! KeyConfig is a very nice and simple to use Add-On and will certainly be added to my default Firefox pack from now on, ace!

Take for example this, imagine having a long hostname, with an odd port and a different user. Typing that would be a pain, most people would do something like:

alias ssh-short="ssh -p 12345 someotheruser@somelong.hostname.com"

In their ~/.bashrc, however the same can be filled into the configuration file. Edit the file ~/.ssh/config (or make it!):

Host short
  HostName somelong.hostname.com
  User someotheruser
  Port 12345

After doing this you can simply do:

$ ssh short

How much easier do you need it to be?!

unrar t file.rar
if [ $? -eq 0 ]; then
  echo "Rar file is good?"
fi

However it was returning zero all the time, even when the file wasn’t a rar:

# unrar t file.rar
 
UNRAR 3.80 freeware      Copyright (c) 1993-2008 Alexander Roshal
 
file.rar is not RAR archive
# echo $?
0

So it fails the test but returns zero regardless. This makes it very unhelpful for using in scripting. Fortunately enough a mate on IRC discovered that his version did.

So I first download the existing SRPM and installed it:

# yumdownloader --source unrar
# rpm -i unrar*.srpm

Then I installed that and simply modified so I downloaded the latest, created a RPM and installed.

I have submitted the updated spec file to RPMfusion.

The first step is to get your drivers and for Broadcom, which is relatively easy as they produce them for us. So first download the driver (these drivers support BM4311-, BCM4312-, BCM4321-, and BCM4322-based cards) and was also successful in this case with BCM4328.

Check that the package ‘linux-headers’ is installed, this is really just for completeness sakes. Gentoo would not work for long without this package!

(gentoo)# emerge linux-headers
... output ...

Unpack the downloaded drivers and build for your current kernel:

(gentoo)# tar -xzf hybrid-portsrc-ARCH-VERSION.tar.gz
(gentoo)# make -C /lib/modules/`uname -r`/build M=`pwd`
... output ...

Remove any existing wireless drivers.

(gentoo)# rmmod ndiswrapper b43 ssb bcm43xx b43legacy

Add in some modules required for WPA wireless:

(gentoo)# modprobe ieee80211_crypt_tkip

Test the newly built wireless driver:

(gentoo)# insmod wl.ko
(gentoo)# iwconfig
.. output ...
(gentoo)# iwlist scanning
... output ...

If that is working we can copy in the driver to the kernel and add to the autoload:

(gentoo)# cp wl.ko /lib/modules/`uname-r`/kernel/net/wireless/
(gentoo)# rmmod wl
(gentoo)# modprobe wl
(gentoo)# echo 'wl' >>/etc/modules.autoload.d/kernel-2.6

So now we have a working driver we can go on to configure for WPA. Alter the /etc/conf.d/net (note we assume that eth0 is wireless):

# Prefer wpa_supplicant over wireless-tools
modules=( "wpa_supplicant" )
 
# It's important that we tell wpa_supplicant which driver we should
# be using as it's not very good at guessing yet
wpa_supplicant_eth0="-Dmadwifi"

Next set up the network in the /etc/wpa_supplicant/wpa_supplicant.conf:

# This setting is required or the connection will not work
ctrl_interface=/var/run/wpa_supplicant
 
# Ensure that only root can read the WPA configuration
ctrl_interface_group=0
 
# Let wpa_supplicant take care of scanning and AP selection
ap_scan=1
 
# Only WPA-PSK is used. Any valid cipher combination is accepted
network={
  ssid="example"
  proto=WPA RSN   # RSN is needed for WPA2
  key_mgmt=WPA-PSK
  pairwise=CCMP TKIP
  group=CCMP TKIP WEP104 WEP40
  psk=06b4be19da289f475aa46a33cb793029d4ab3db7a23ee92382eb0106c72ac7bb
  #The higher the priority the faster it connects
  priority=2
}

And that is it, you should find that your wireless is enabled on boot.

Thanks should also go to DJ Kaos for the preparation of the driver.

I have owned this dinky wee notebook for sometime now and can highly advise it for anyone looking for a Linux Notebook.

Some tricks I have are:

Alt+F2 > xfce-settings-show > Desktop > Behaviour > Show desktop menu on right click.
The will enable the XFCE menu on right click, which is useful to me.

Alt+F2 > xfce-settings-show > Sessions and Startup > Advanced > Launch Gnome services on startup
This will allow NetworkManger to use gnome-keyring and therefore finally store the keys for wireless!

Simple but effective!

Simply download the key by using the GPG tool:

gpg --keyserver pgpkeys.mit.edu --recv-key E6F33B6628973CC0

Then import that key into either apt:

gpg -a --export 010908312D230C5F | sudo apt-key add -

Or rpm:

gpg --export -a 010908312D230C5F >key.txt
rpm --import key.txt

Simple!