lost and found ( for me ? ): January 2014

tcprewrite and tcprepaly : rewrite a cap file and replay UDP traffic

Here is how to rewrite capture file and replay that with tcpreplay and tcprewrite.

root@ubuntu:~:# tail -1 /etc/lsb-release
DISTRIB_DESCRIPTION="Ubuntu 13.10"

root@ubuntu:~:# apt-get install tcpreplay

root@ubuntu:~:# dpkg -l tcprepaly
+++-==============-============-============-=================================
ii tcpreplay 3.4.4-2 amd64 Tool to replay saved tcpdump file

my_dns_query.cap is DNS cap file collected with tcpdump.
rewrite dst ip address to 192.168.11.1

# tcprewrite --infile=my_dns_query.cap --outfile=new.cap --dstipmap=0.0.0.0/0:192.168.11.1/32

original: dst ip 8.8.8.8

root@ubuntu:~:# tcpdump -r my_dns_query.cap -n | head -1
reading from file my_dns_query.cap, link-type EN10MB (Ethernet)
00:13:52.094051 IP 192.168.11.100.14751 > 8.8.8.8.53: 65266+ A? ocsp.verisign.com. (35)

after rewriting : dst ip 192.168.11.1

root@ubuntu:~:# tcpdump -r new.cap -n | head -1
reading from file new.cap, link-type EN10MB (Ethernet)
00:13:52.094051 IP 192.168.11.100.14751 > 192.168.11.1.53: 65266+ A? ocsp.verisign.com. (35)

replay packet

# tcpreplay -i br0 new.cap --pps=10
sending out br0
processing file: new.cap

okay.

root@ubuntu:~:# tcpreplay --pps=100 --intf1=br0 new.cap
sending out br0
processing file: new.cap
Actual: 722 packets (57514 bytes) sent in 7.28 seconds. Rated: 7900.3 bps, 0.06 Mbps, 99.18 pps
Statistics for network device: br0
Attempted packets: 722
Successful packets: 722

root@ubuntu:~:# tcpdump -r new.cap | wc -l
reading from file new.cap, link-type EN10MB (Ethernet)
722

root@ubuntu:~:# tcpdump -i br0 udp dst port 53 -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on br0, link-type EN10MB (Ethernet), capture size 65535 bytes
01:54:00.827695 IP 192.168.11.100.28689 > 192.168.11.1.53: 17014+ A? workplace.stackexchange.com. (45)
01:54:00.837693 IP 192.168.11.100.5017 > 192.168.11.1.53: 64629+ A? apple.stackexchange.com. (41)

Ubuntu 13.10 : LXC

Reference

https://help.ubuntu.com/13.10/serverguide/lxc.html

# tail -1 /etc/lsb-release ;uname -ri

DISTRIB_DESCRIPTION="Ubuntu 13.10"

3.11.0-15-generic x86_64

install lxc

# apt-get install lxc lxc-templates

# dpkg -l lxc*

+++-==============-============-============-=================================

ii lxc 1.0.0~alpha1 amd64 Linux Containers userspace tools

ii lxc-templates 1.0.0~alpha1 all Linux Containers userspace tools

[ setup ]

Here are config files which are under /etc/init directory.

# ls /etc/init/lxc*

/etc/init/lxc.conf /etc/init/lxc-instance.conf /etc/init/lxc-net.conf

/etc/default/lxc is config file as well.

- use br0 tied to eth0

edit /etc/default/lxc-net

# egrep -v ^# /etc/default/lxc-net

USE_LXC_BRIDGE="false"

LXC_BRIDGE="br0"

LXC_ADDR="10.0.3.1"

LXC_NETMASK="255.255.255.0"

LXC_NETWORK="10.0.3.0/24"

LXC_DHCP_RANGE="10.0.3.2,10.0.3.254"

LXC_DHCP_MAX="253"

# cat /etc/lxc/default.conf

lxc.network.type = veth

#lxc.network.link = lxcbr0

lxc.network.link = br0

lxc.network.flags = up

interfaces file is as below.

# cat /etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)

auto lo

iface lo inet loopback

auto eth0

iface eth0 inet manual

auto br0

iface br0 inet static

address 192.168.11.100

netmask 255.255.255.0

gateway 192.168.11.1

dns-nameservers 127.0.0.1 8.8.8.8

bridge_ports eth0

bridge_stp off

bridge_fd 0

bridge_maxwait 0

[ directory where containers are stored ]

/var/lib/lxc : containers are stored

/var/cache/lxc : cached data are stored ( I am not sure .. )

If you want to change the directory where containers stored, create symbolic links like this:

# rm -rf /var/lib/lxc /var/cache/lxc/

root@ubuntu:~:# mkdir /var/disk1/lxclib

root@ubuntu:~:# mkdir /var/disk1/lxccache

root@ubuntu:~:# ln -s /var/disk1/lxclib /var/lib/lxc

root@ubuntu:~:# ln -s /var/disk1/lxccache /var/cache/lxc

[ build containers by using templates ]

here is the list of container templates you can build.

# ls /usr/share/lxc/templates/

lxc-alpine lxc-busybox lxc-fedora lxc-sshd

lxc-altlinux lxc-cirros lxc-opensuse lxc-ubuntu

lxc-archlinux lxc-debian lxc-oracle lxc-ubuntu-cloud

build ubuntu 13.10 container.

-t means use template ( lxc-ubuntu )

-n : container name

-- : template option

-r : distribution name

# lxc-create -t ubuntu -n ubuntu1310-cn1 -- -r saucy

Checking cache download in /var/cache/lxc/saucy/rootfs-amd64 ...

installing packages: vim,ssh,language-pack-en,language-pack-ja

Downloading ubuntu saucy minimal ...

I: Retrieving Release

I: Retrieving Release.gpg

<snip>

# The default user is 'ubuntu' with password 'ubuntu'!

# Use the 'sudo' command to run tasks as root in the container.

okay.

:# ls /var/lib/lxc/ubuntu1310-cn1/*

/var/lib/lxc/ubuntu1310-cn1/config /var/lib/lxc/ubuntu1310-cn1/fstab

/var/lib/lxc/ubuntu1310-cn1/rootfs:

bin dev home lib64 mnt proc run srv tmp var

boot etc lib media opt root sbin sys usr

start the container

# lxc-ls --fancy

NAME STATE IPV4 IPV6 AUTOSTART

----------------------------------------------

ubuntu1310-cn1 STOPPED - - NO

# lxc-start -n ubuntu1310-cn1

[ clone ]

stop the container and then clone

root@ubuntu:~:# lxc-stop -n ubuntu1310-cn1

root@ubuntu:~:# lxc-clone -o ubuntu1310-cn1 -n ubuntu1310-cn2

Created container ubuntu1310-cn2 as copy of ubuntu1310-cn1

Apache CGI, python script

small tips.

# tail -1 /etc/lsb-release ;uname -ri

DISTRIB_DESCRIPTION="Ubuntu 12.04.4 LTS"

3.2.0-58-virtual x86_64

install apache2

# apt-get install apache2

edit /etc/apache2/mods-available/mime.conf to allow us to execute cgi, pl, rb, py scripts.

AddHandler cgi-script .cgi .pl .rb .py

# less /etc/apache2/sites-available/default

ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/

AllowOverride None

Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch

Order allow,deny

Allow from all

</Directory>

start httpd

# apachectl restart

create a python script for the testing and copy it to /usr/lib/cgi-bin directory.

also change permission of python file.

# cat example1.py

#!/usr/bin/env python

print "Content-type: text/html"

print "<html>"

print "<center>Hello, Linux.com!</center>"

print "</html>"

# cp example1.py /usr/lib/cgi-bin/

# chmod 755 /usr/lib/cgi-bin/example1.py

access to http:// IP /cgi-bin/example1.py

[ FORM ]

Reference

http://hp.vector.co.jp/authors/VA003670/python/CGI/QueryStr.htm

html file ( form )

# cat /var/www/example2.html

<html>

<head>

<title>Python CGI Test(1)</title>

</head>

<body>

<h1>Python CGI Test(1)</h1><hr><p>

name: <input type="text" size=30 name="name"><p>

addr: <input type="text" size=30 name="addr"><p>

</form>

</body>

</html>

python script

# cat /var/www/cgi-bin/example2.py

#!/usr/bin/env python

# CGI Test

import cgi

print "Content-Type: text/html\n\n"

print "<html><body>"

form = cgi.FieldStorage()

form_ok = 0

if form.has_key("name") and form.has_key("addr") :

form_ok = 1

if form_ok == 0 :

print "<h1>ERROR</h1>"

else :

print "<h2>Result</h2><hr><p>"

print "<p><b>name: </b>", form["name"].value

print "<p><b>addr: </b>", form["addr"].value

print "</body></html>"

copy the script to /vaw/www/cgi-bin directory.

# mkdir /var/www/cgi-bin <- create a directory if there is not

# cp example2.py /var/www/cgi-bin/

# chmod 755 /var/www/cgi-bin/example2.py

access to http:// IP /example2.html

enter “submit”

Fedora 20 : install Go 1.2 lang

Reference

http://golang.org/

# cat /etc/fedora-release ;uname -ri

Fedora release 20 (Heisenbug)

3.13.0-1.vanilla.mainline.knurd.1.fc20.x86_64 x86_64

download go lang from https://code.google.com/p/go/downloads/list

untar file and store these file under /usr/local/go directory

# tar -C /usr/local -xzf go1.2.linux-amd64.tar.gz

# ls /usr/local/go

AUTHORS LICENSE README api blog favicon.ico lib pkg src

CONTRIBUTORS PATENTS VERSION bin doc include misc robots.txt test

# export PATH=$PATH:/usr/local/go/bin

# which go

/usr/local/go/bin/go

# go version

go version go1.2 linux/amd64

make a go file

# cat hello.go

package main

import "fmt"

func main() {

fmt.Print("hello\n")

}

run

# go run hello.go

hello