generate random number

use Linear_congruential_generator

http://en.wikipedia.org/wiki/Linear_congruential_generator

r = a X + c

X is the initail seed. we can use the TSC value for that. And we use the current random number to generate the next random number. The parameters of a and c are form:

Source	m	(multiplier) a	(increment) c	output bits of seed in rand() / Random(L)
Numerical Recipes	232	1664525	1013904223

Here is some code I wrote:

// Generate Random Number using Linear congruential generator
/*
#define MULTIPLIER 1664525
#define INCREMENT 1013904223

// save the seed in the SMRAM
// SMM_BASE + 0xFD00
unsigned int *saved_seed = (unsigned int*)(SMM_BASE + 0xFD00);

// Get a seed from tsc
//u32 initial_seed = (u32)(get_rdtsc() >> 32);
// *saved_seed = initial_seed;

u32 rand = 0xfff & (MULTIPLIER*(*saved_seed) + INCREMENT);
*saved_seed = rand;

// printk(BIOS_DEBUG,"rand is: %x\n", rand);
// the random number is resides in [1, 0xffff]

compile latex

two ways:
1. use pdflatex: compile latex to pdf
$latexpdf main.tex

this method does not work well with .eps images

2. use latex: compile latex to dvi; then use dvipdfm: compile dvi to pdf
$latex main.tex
$dvipdfm main.dvi

bibtex main.tex generates all of the .bbl. you can manually put it in the main.tex


sample Makefile for method 1

TARGETS = main

LATEX = pdflatex

BIBTEX = bibtex

all:    $(TARGETS) debug

$(TARGETS):

$(LATEX) $@

$(BIBTEX) $@ > $(BIBTEX)_out.log

debug:

-grep Warning *.log

clean:  

rm -f images/*.aux images/*~ images/*.log *.aux *.bbl *.blg *.log *.dvi *.bak *~ $(TARGETS:%=%.pdf)

sample Makefile for method 2

TARGETS = main

LATEX = latex

DVIPDFM = dvipdfm

BIBTEX = bibtex

all:    $(TARGETS) debug

$(TARGETS):

$(LATEX) $@

-$(BIBTEX) $@ > $(BIBTEX)_out.log

$(DVIPDFM) $@

debug:

-grep Warning *.log

clean:  

rm -f *.aux images/*.aux *.bbl *.blg *.log images/*.log *.dvi *.bak *~ $(TARGETS:%=%.pdf)

convert pdf to eps

$ pdftops -eps <pdf file> <eps file>

Set a static internal IP

1. find a hooked interface

2. make a script in /etc/sysconfig/network-scripts
For example:
$cd /etc/sysconfig/network-scripts
$touch ifcfg-em1
$vim ifcfg-em1

DEVICE=em1

HWADDR=A4:BA:DB:1A:AC:4F this is the mac address of the interface

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=no

BOOTPROTO=static

IPADDR=192.168.0.27 this is the static IP you want to set

BROADCAST=192.168.0.255

NETMASK=255.255.255.0

NAME=em1

3. restart the device

$ ifdown em1

$ ifup em1

4. finally, check if the static ip has been assigned to interface em1

$ ifconfig

Check if the interface hook or not

$ yum install ethtool

$ ifconfig to see how may interfaces available

$ ethtool [Interface Name]

[root@sr2s7 home]# ethtool em1

Settings for em1:

        Supported ports: [ TP ]

        Supported link modes:   10baseT/Half 10baseT/Full 

                                100baseT/Half 100baseT/Full 

                                1000baseT/Full 

        Supported pause frame use: No

        Supports auto-negotiation: Yes

        Advertised link modes:  10baseT/Half 10baseT/Full 

                                100baseT/Half 100baseT/Full 

                                1000baseT/Full 

        Advertised pause frame use: No

        Advertised auto-negotiation: Yes

        Speed: 1000Mb/s

        Duplex: Full

        Port: Twisted Pair

        PHYAD: 1

        Transceiver: internal

        Auto-negotiation: on

        MDI-X: Unknown

        Supports Wake-on: g

        Wake-on: d

        Link detected: yes Means the link is hooked.

mount NFS using /etc/fstab

First, you may need to authenticate the local machine to the NFS server.

Then,

Please add the following line to the end of your /etc/fstab:

NFS_SERVER:/vol/vol1_home    /home           nfs4    defaults        1 1

This is the format:
SERVERIP:REMOTE_FILE      LOCAL_FILE    FILE_FORMAT 

After this, do "mount -a" should get your home directory mounted.

Other commands about mount:
mount -a: mount all of the files in /etc/fstab
umount /home: unmount the local home direcotry from NFS server

Good summary of SRTM and DRTM

http://security.hsr.ch/mse/projects/2011_Root_of_Trust_for_Measurement.pdf