20090131
20081216
Hacking a codegen
So, finally I’ve hacked a basic AMD64 code generator, after so many tries. This code generator is hacked in Common Lisp, and is currently generating a code for a very simple toy like language. I’ve not written any grammar specification for it. It is a LISP like language. This piece of code generator is dedicated to one of my cool friend Edwin Jose, and is thus named as louzer. Following is an example of the language for which louzer generates code.
(source (let principal rate time amount x) (= principal 1000) (= rate 10) (= time 100) (= x 100) (= amount (/ (* principal (* rate time)) 100)) (print "Amount (%d) - %d is %d.\\n" amount x (- amount x)) (print "Hello World, louzer\\n"))
The language code is also embedded along with the source code in the LISP file. Following is how I’m using it with GNU clisp implementation:
% clisp louzer.lisp |tee test.S .section .text .extern printf .type main,@function .globl main main: pushq %rbp movq %rsp, %rbp subq $40, %rsp movq $1000, %rbx movq %rbx, -8(%rbp) movq $10, %rbx movq %rbx, -16(%rbp) movq $100, %rbx movq %rbx, -24(%rbp) movq $100, %rbx movq %rbx, -40(%rbp) movq -16(%rbp), %rbx imul -24(%rbp), %rbx imul -8(%rbp), %rbx movq %rbx, %rax movq $100, %rbx xorq %rdx,%rdx idiv %rbx movq %rax, -32(%rbp) leaq __string_0,%rdi movq -32(%rbp), %rsi movq -40(%rbp), %rdx movq -32(%rbp), %rbx subq -40(%rbp), %rbx movq %rbx, %rcx xorq %rax,%rax call printf leaq __string_1,%rdi xorq %rax,%rax call printf xorq %rax, %rax movq %rbp, %rsp popq %rbp ret .section .rodata __string_1: .string "Hello, louzer World\n" __string_0: .string "Amount (%d) - %d is %d.\n" /* Generated by louzer :) */
Above is the piece of AMD64 assembly code emitted by the louzer. So, now time to assemble and link the above assembly code and generate the output of the above code.
% cc -o test test.S % ./test Amount (10000) - 100 is 9900. Hello, louzer World
Voila. Oh, sorry to keep you waiting, now you can download the louzer.lisp and have fun. BtW, code is not perfect and has couple of limitations, which I’ve not fixed due to lack of time, as I’ve an exam day after tomorrow. So, I’ll be able to work on it only after 20081219. Happy hacking codegens…;)
NOTE (for Grammar Nazis): Forgive me for any grammatical mistakes you encounter above, and ofcourse point out the mistake :).
P.S. Forgot to mention, you’ll need an AMD64 architecture CPU, toolchain and POSIX OS to test out above stuff.
20080910
Google IPv6 endpoint in Europe
┌─(abbe@chateau:pts/8)───────────────────────────────────────────────────────────────────────(~)─┐ └─(08:41:%)── sudo traceroute -6 -I -n 2001:4860:0:2001::68 ──(Wed,Sep10)─┘ Password: traceroute to 2001:4860:0:2001::68 (2001:4860:0:2001::68), 30 hops max, 40 byte packets 1 2001:470:1f08:3b7::1 255.608 ms 258.492 ms 261.419 ms 2 2001:470:0:67::1 263.345 ms 266.538 ms 269.720 ms 3 2001:470:0:3f::2 282.060 ms 283.483 ms 285.925 ms 4 * * * 5 * * * 6 2001:4860:0:2001::68 556.875 ms 503.697 ms 510.901 ms ┌─(abbe@chateau:pts/8)───────────────────────────────────────────────────────────────────────(~)─┐ └─(08:41:%)── sudo traceroute -6 -I -n 2001:4860:0:1001::68 ──(Wed,Sep10)─┘ traceroute to 2001:4860:0:1001::68 (2001:4860:0:1001::68), 30 hops max, 40 byte packets 1 2001:470:1f08:3b7::1 256.051 ms 258.644 ms 261.619 ms 2 2001:470:0:67::1 264.279 ms 266.755 ms 269.970 ms 3 2001:470:0:3f::2 281.020 ms 283.444 ms 286.494 ms 4 * * * 5 * * * 6 2001:4860:0:1001::68 558.181 ms 516.731 ms 511.211 ms
2001:4860:0:1001::68 points to the European cluster (in Amsterdam, as mentioned by berniv6 on #ipv6 in ipv6.chat.freenode.net) of ipv6.google.com, whereas 2001:4860:0:2001::68 (ipv6.google.com) is known to be located in US. My tunnel remote endpoint (2001:470:1f08:3b7::1|216.66.80.26) is located in London, UK. Notice the RTT ;)
20080530
Getting 8139too to work at 100 Mbps Full Duplex
I recently switched to my RTL-8139 NIC instead of default onboard Intel NIC, after I came to know that e100 uses binary blobs. I’ve a Netgear WGT624 WiFi router (acting as switch, atm). I plug-in my desktop at a 100 Mbps switch port in the switch. So now when I connected my RTL8139 NIC to my wireless enabled wired-switch, it comes online at 10 Mbps (full-duplex)
abbe@chateau ~ $ sudo ethtool rl0
Settings for rl0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: No
Speed: 10Mb/s
Duplex: Full
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: p
Current message level: 0x00000007 (7)
Link detected: yes
Now, I tried manually switching it 100 Mbps (full-duplex):
abbe@chateau ~ $ sudo ethtool -s rl0 speed 10
abbe@chateau ~ $ sudo ethtool rl0
Settings for rl0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: p
Current message level: 0x00000007 (7)
Link detected: yes
Now, to automate this, I added following line into /etc/modprobe.d/options and executed update-modules.
abbe@chateau ~ $ cat /etc/modprobe.d/options
options 8139too media=0x231
abbe@chateau ~ $ sudo modprobe -r 8139too
abbe@chateau ~ $ sudo update-modules
* Updating /etc/modprobe.conf by hand ... [ ok ]
* Updating modules.dep ... [ ok ]
abbe@chateau ~ $ sudo modprobe 8139too
abbe@chateau /etc/modprobe.d $ sudo /usr/sbin/ethtool rl0
Settings for rl0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: pumbg
Wake-on: p
Current message level: 0x00000007 (7)
Link detected: yes
How to arrive at the number 0×231, check out modinfo 8139too and drivers/net/8139too.c source code. BtW, I just noticed that rl0 has auto-negotiation off, so I decided to turn it on, and following are the results:
abbe@chateau ~ $ sudo ethtool -s rl0 autoneg on
abbe@chateau ~ $ sudo ethtool rl0
Settings for rl0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 10Mb/s
Duplex: Half
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: p
Current message level: 0x00000007 (7)
Link detected: no
abbe@chateau ~ $ sudo ethtool -s rl0 speed 100 duplex full
abbe@chateau ~ $ sudo ethtool rl0
Settings for rl0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 32
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: p
Current message level: 0x00000007 (7)
Link detected: yes
After this I tried testing network speed using iperf, and got speeds of ~ 67 Mbps. With e100, I used to get ~ 97 Mbps. Anyways this is an 3-4 year old NIC, plugged (and unused) into my desktop unused since 2-3 years. So will try testing speeds with a new NIC soon.
20080507
Spoofing on Internet
Although it seems like dream to be able to successfully spoof on Internet in 21st century, but I realized this dream, yesterday. Thanks to the cheapest cyber café operator Tata Communications pretending to be an ISP. :)
I’ve a GNU/Linux box connected to the internet, via 2 ADSL internet connections from 2 cyber café operators, namely Airtel Broadband (not cheap), and Tata Communications (cheapest). Airtel Broadband connection is connected to my GNU/Linux box at eth1 interface, and Tata Communications connection is connected to eth2 interface. eth1 is assigned a RFC1918 IPv4 address, whereas eth2 is assigned a static and globally routable IPv4 address. Using eth2‘s address, I’ve setup a 6to4 tunnel, with interface name sit0 for my IPv6 internet addiction.
Now, yesterday I wasn’t able to ping google.com via eth2, though I recieved no ICMP errors from gateway. So I switched my default gateway to eth1. And after this, I’m able to ping google.com :). I thought I should also try ping6 ipv6.google.com though I’m sure that it won’t work, since sit0‘s source address is based on eth2‘s address, which is different from the current default gateway interface’s address, eth1. But to my surprise, it worked. I’m getting ICMP echo replies from ipv6.google.com :).
To confirm further, I tried curl http://ipv6.whatismyipv6.net/ |fgrep 'Your IP is' and I received sit0‘s IPv6 address as output. :). Now, this is confusing. Even though I’m able to send spoofed packets, but how I’m receiving replies of those spoofed packets, if internet connection on eth2 is not working, hmm…? So, I connected to #ipv6@ipv6.chat.freenode.net (being able to IRC over IPv6) to figure out what is happening, and at the same time I started sudo tcpdump -i eth2 proto 41 on another terminal to confirm whether I’m really receiving any IPv6-in-IPv4 packets on eth2 interface. And as expected, I’m getting IPv6 traffic over eth2. I thought maybe Tata Communications‘s connectivity has restored, but no success with sudo ping -I eth2 google.com :(. So I asked p1mrx on #ipv6@ipv6.chat.freenode.net to ping IPv4 address of eth2 and I started sudo tcpdump -i eth2 proto icmp in another terminal. I captured ICMP echo requests sent by h{is,er} box and also captured ICMP echo replies sent from my box. {S,}he confirmed that ping is successful.
CONCLUSION. The cheapest cyber café operator Tata Communications, pretending to be an ISP, is dropping my outbound traffic (TCP, UDP, ICMP echo request) but idiot operator’s dumb clueless retarted (and some more words you can think of…..) cyber café incharges, who never studied IPv4 networks, or don’t know that there is a protocol field (size: 1 byte) in the IPv4 header, which identifies what kind of payload that IPv4 packet is carrying, and has forgot to block all other protocols, ROFL. But why’re they doing this. /me is confused why they’ve blocked. Anyways I’ll call them today. Another reason why they’re retarded….
/me is confused how Indian cyber café operators will become an ISP and transition to IPv6 :(
20071025
/me traced again
After this, I traced again my photo, but this time a current one :). Following is the link to the SVG source for vector graphics fans, scale me as much as you can :)
20071009
dd if=/dev/hda of=/dev/sdb bs=64M
Just finished, dding my ST3160812AV (160 GB/PATA/Seagate) onto ST3160812AS (160 GB/SATA/Seagate):
chatteau ~ # dd if=/dev/hda of=/dev/sdb bs=64M 9+0 records in 8+0 records out 536870912 bytes (537 MB) copied, 10.5324 s, 51.0 MB/s 26+0 records in 26+0 records out 1744830464 bytes (1.7 GB) copied, 29.3277 s, 59.5 MB/s 35+0 records in 34+0 records out 2281701376 bytes (2.3 GB) copied, 38.9617 s, 58.6 MB/s 77+0 records in 76+0 records out 5100273664 bytes (5.1 GB) copied, 84.8692 s, 60.1 MB/s 104+0 records in 103+0 records out 6912212992 bytes (6.9 GB) copied, 114.29 s, 60.5 MB/s 197+0 records in 196+0 records out 13153337344 bytes (13 GB) copied, 216.665 s, 60.7 MB/s 267+0 records in 267+0 records out 17918066688 bytes (18 GB) copied, 294.418 s, 60.9 MB/s 796+0 records in 796+0 records out 53418655744 bytes (53 GB) copied, 895.93 s, 59.6 MB/s 1783+0 records in 1782+0 records out 119587995648 bytes (120 GB) copied, 2173.03 s, 55.0 MB/s 2333+0 records in 2332+0 records out 156497870848 bytes (156 GB) copied, 3087.42 s, 50.7 MB/s 2380+0 records in 2379+0 records out 159651987456 bytes (160 GB) copied, 3185.21 s, 50.1 MB/s 2384+1 records in 2384+1 records out 160041885696 bytes (160 GB) copied, 3198.33 s, 50.0 MB/s
The whole process took less than an hour as compared to 1 hr. 25 min. when I dded my SATA disk to PATA disk.
20070917
/me traces my face
Using Inkscape and with the help of Nicu‘s tutorial, I’m able to trace my photo. The output is not excellent, but I enjoyed the process :-) . Inkscape rocks. Following is the link to SVG of the picture:
http://wahjava.googlepages.com/my-face-shaded2.svg
In order to render above SVG, make sure SVG renderer is capable of rendering <feGaussianBlur> SVG filter. Inkscape and Apache Batik are able to render SVG properly.
20070803
20070720
dd if=/dev/sdb of=/dev/sda bs=64943040
Just finished, dding my ST3160812AS (160 GB/SATA/Seagate) onto ST3160812AV (160 GB/PATA/Seagate):
sh-3.2# dd if=/dev/sdb of=/dev/sda bs=64943040 8+0 records in 8+0 records out 519544320 bytes (520 MB) copied, 9.68668 s, 53.6 MB/s 13+0 records in 13+0 records out 844259520 bytes (844 MB) copied, 17.9687 s, 47.0 MB/s 19+0 records in 19+0 records out 1233917760 bytes (1.2 GB) copied, 27.9116 s, 44.2 MB/s 217+0 records in 217+0 records out 14092639680 bytes (14 GB) copied, 400.011 s, 35.2 MB/s 454+0 records in 453+0 records out 29419197120 bytes (29 GB) copied, 847.458 s, 34.7 MB/s 529+0 records in 528+0 records out 34289925120 bytes (34 GB) copied, 991.407 s, 34.6 MB/s 670+0 records in 669+0 records out 43446893760 bytes (43 GB) copied, 1260.98 s, 34.5 MB/s 673+0 records in 672+0 records out 43641722880 bytes (44 GB) copied, 1266.12 s, 34.5 MB/s 763+0 records in 763+0 records out 49551539520 bytes (50 GB) copied, 1443.54 s, 34.3 MB/s 820+0 records in 819+0 records out 53188349760 bytes (53 GB) copied, 1552.44 s, 34.3 MB/s 1099+0 records in 1099+0 records out 71372400960 bytes (71 GB) copied, 2103.98 s, 33.9 MB/s 1144+0 records in 1144+0 records out 74294837760 bytes (74 GB) copied, 2194.04 s, 33.9 MB/s 1329+0 records in 1328+0 records out 86244357120 bytes (86 GB) copied, 2568.23 s, 33.6 MB/s 1356+0 records in 1356+0 records out 88062762240 bytes (88 GB) copied, 2623.02 s, 33.6 MB/s 1440+0 records in 1440+0 records out 93517977600 bytes (94 GB) copied, 2795 s, 33.5 MB/s 1638+0 records in 1637+0 records out 106311756480 bytes (106 GB) copied, 3211.79 s, 33.1 MB/s 1782+0 records in 1781+0 records out 115663554240 bytes (116 GB) copied, 3521.31 s, 32.8 MB/s 2033+0 records in 2033+0 records out 132029200320 bytes (132 GB) copied, 4085.72 s, 32.3 MB/s 2144+0 records in 2143+0 records out 139172934720 bytes (139 GB) copied, 4344.01 s, 32.0 MB/s 2300+0 records in 2299+0 records out 149304048960 bytes (149 GB) copied, 4724.12 s, 31.6 MB/s 2388+0 records in 2388+0 records out 155083979520 bytes (155 GB) copied, 4950.18 s, 31.3 MB/s 2447+0 records in 2446+0 records out 158850675840 bytes (159 GB) copied, 5106.49 s, 31.1 MB/s 2464+1 records in 2464+1 records out 160041885696 bytes (160 GB) copied, 5171.74 s, 30.9 MB/s
