Aliasing an Ethernet Interface in Linux

For the last couple of weeks, I was busy with my work. I’ve had a really good time and I thought I will share something I learned during that time here.

My work was related to some thing of the client-server model. For testing, we were simulating multiple clients and servers in the same PC. First we were using the same IP address and different ports. Later, before moving to the real world scenario, we wanted to test with different IP address. Since the number of clients was huge, we couldn’t run the tests in single PCs. Thats then we decided to bring up multiple interfaces in a single PC and test it. This helped in testing one more level deeper before moving to the actual hardware. [Even then, we had to use different TCP/UDP ports since there is only one TCP/UDP stack in the system]

For this purpose, I was doing some research on how to alias and bring up multiple Ethernet interfaces in a Linux system. I couldn’t easily find any help on how to bring up aliased interfaces using C [I found many references about aliasing using Ifconfig command]. So, I wrote a generic application which can bring up multiple aliased interfaces. Here is the code. I believe I have made it as simple as I can and you can modify and try experiments on your own. To start with, you can try changing different members in the ifreq structure.

When I showed this to a colleague of mine - who happens to be a scripting guru - he wrote a small script which can be used to bring up multiple interfaces. This may also be useful I guess. Anyway, you are free to take this and do experiments on your own.

For more info about the structures used in the program, here are the links.
struct sockaddr_in
struct ifreq
Please share your comments and thoughts so that I can improve the ways I do coding. Special thanks to Bala who wrote the script and Adil, who provided me with the code to start off with.

ps: I am really sorry that I have put the code as an image, I don't know why, but I was not able to put the code as it is, it was giving me some problems.

The Lake House

I’ve always wondered how they make such beautiful stories about love, capture it in the film so perfect that you never want to come out of the magical world, the movie has taken you to. I’ve stumbled up on one such movie recently.

It was a rainy day. I love to simply sit in my house, look out through the glass window, and see the rain. I was alone in my home. The mood was getting on to me. I felt lonely. I selected the movie “The Lake House” as a pass time, just because of my love towards buildings by river/lake sides. But it turned out to be an amazing movie.

The movie had all the elements I would love spending all my time for. A ‘seductively beautiful’ house by the lake side- a glass box - which gives you a gorgeous view of the lake, almost like one which I always dream of building myself, a gifted architect (a profession which I admire) who lives in the house, a really scenic place – something which I long to own one day, those sunsets you can enjoy from the lake house, and a beautiful story of love which is so impossible and mysterious, where there is no place for logic, but one which make you wish that it is real. And a magical mailbox, which makes everything a reality.


“What if you found, the one you were meant for? But you lived two years apart?” What if the one person who walked right in to your life, turned it around, is two years apart from your life? One person whom you can never meet, but the one you want to give your whole heart to. Even though its clearly impossible, it’s amazing to see what love can do to us, all of us.


Yeah, that’s the theme of the movie. Sounding absurd? It sounded the same way to me when I saw the trailer. Now it’s another fairytale which I like to keep very close to my heart.







Trailer: http://www.apple.com/trailers/wb/thelakehouse/small.html
Site: http://thelakehousemovie.warnerbros.com/

Guilty as Charged

Here is the reply I got from the Mr. B Krishnamoorthy Bajaj Regional Manager, Bangalore about my complaint (previous blog).

Dear Mr Manu,
Noted the contents of your mail and we sincerely apologise for the experience which you had with our service centre.

Your feedbacks are very valid and would help the dealer to improve on customer service
We are taking up the feedback with the concerned dlr and we assure you better experience during your future visits.
For any future service assistance pl contact me or my colleague Mr Manoj Manoharan, from our Bangalore Regional office.
Assuring our best services.
Regards,

B Krishnamoorthy
Regional Manager-Service
Bajaj auto ltd
Bangalore

Atleast I got the satisfaction that I had done something to resist customer exploitation. After I got this mail, I got a call from another guy (forgot his name) on behalf of Mr. B Krishnamoorty apologizing for the incident. He said it’s good that I submitted the feedback, so that they can improve customer service. He also assured me that there had been some internal action taken and the corresponding person from Amba Bajaj will call me. As expected, Mr. Hithranjan Kumar from Amba Bajaj called me and we ‘discussed’ about the incident for some 15-20 minutes. Finally he concluded that, its their mistake and he apologized for that and he assured me that I can contact him anytime for any assistance. He also wanted me to reply to the regional manager’s mail about our discussion. Anyway, I now feel that there is some customer service after all, and some one will reply to the complaints of a customer, if you complain at the right place.

Thanks to Amba Bajaj

This is the mail I had to send to customerservice@bajajauto.co.in (and to the regional heads) today. Thanks to Amba Bajaj.

From,

Manu Ignatius

To Whom It May Concern:

Bajaj Customer Service

Bajaj Auto India Ltd.

Subject: Feedback about customer service

Sir,

I own a Bajaj Pulsar 180cc, 2006 model bike (vehicle no). And I love it and I take care of it really well. But I am loosing faith on your customer service and dealers. I bought my bike on <date>. During that time, I had some issues and I had to mail to this same email id and I got the bike after a long time.

I gave my bike for 4^th free service yesterday (October 14, 2008) to Amba Bajaj service centre in Hongasandra. (Bill attached). I could not go there to collect my bike yesterday due to some personal reasons. I called them by around 7pm, and they said, bike is ready, but I can collect it today (October 15^th) morning. You can clearly see from the bill that I collected on Oct 15^th. When I went there to collect my bike, it was not ready. After I paid the bill, they started cleaning my bike. Then I noticed that, the bike was not at all clean. There was mud all over the engine, the silencer and the central stand. I was on my way to office and I wanted the bike fast. But, I told them this issue and they said they will do washing again. I had to wait there for 30 mins. I missed a very serious meeting in my office. But it was ok for me, as long as my bike is good. Even after 30mins, when I couldn’t see anyone responsible for the bike, I went inside the service centre and the guy who washed it said its ready and I can take it. The bike was washed, but it was totally wet. I asked them how long will it take to dry it. He said, its ready, and he is not going to dry it. I felt thoroughly cheated, and it was like he slapped in my face. I wanted to complain this to some one, but I couldn’t find anyone who is responsible there. I felt like, no one is accountable for any work in that service centre. I trusted your company and service centers. But if this is the case, where will I go for service?

I saw a label there about your goals. It said, 100% customer satisfaction – in my case its 0% + loss of time + mental agony. Also I saw another goal which says, no repeat works – if I had checked it again, I would have to tell them to wash my bike again. Because it was not clean as I wanted. By these incidents, I am loosing all the faith in your service centers. The bike is a great one, but I don’t know how long I can take this kind of customer treatment from your service centers.

Yours truly,

Manu Ignatius

ps: I have posted an online complaint also regarding this same issue.

A Toast

I am not entirely sure why I am publishing this in my blog. May I want all those who didn't attend the function and didn't get a chance to hear me saying those words, to read them. Anyway, my sister got engaged on Oct 2nd, 2008. And here is the toast, I presented for them.

"Hi everyone, I would like to propose a toast for Milu and Ginto, the best couple in the world, according to me. She is my one and only little sister, speaking of which I have lots of memories. Some are happy; some are not, some are wonderful, so wonderful that I won’t be able to forget any of them in my life time.

When I look back, I am really amazed at how fast it is that the time flies by. I remember vividly, all those times we spent together during our childhood. All our fights, which ended always when either of our parents – Achachan and Amma – intervened. We even spent much of our college days together. Even now, we are very close. My point is, she is one hell of a person, who has influenced me a lot and left a long standing impression in my life. She has always been there for me, through my hard times to help me out and to share my happiness when I was happy.

You know, when I first realized that they are going to get married, which I haven’t done yet, I was, I was little angry and jealous towards Ginto. The mere thought that he is going to take away this integral part of my life, my little treasure, from me, gave me a real hard time. Later when I came to know more about Ginto, I realized that, not only that I am NOT going to loose my dear vava, but I am also gaining a Big brother, which is something I used to wish for. Along with that, I’ve gained another set of parents – Ginto's parents - and a new brother and friend – Anish who is Ginto’s brother. Now I feel that I am going to be the luckiest person in this world to have the best sister and brother-in-law.

You know, I’ve read somewhere that 'true love is the soul's recognition of its counterpoint in another person'. And I think that that's a very rare thing in this world and something to be valued. And I'm really happy that my little sister's found it. Congratulations, my dear sweet sister and her lucky fiancé, Ginto. I wish you both a very adventurous and wonderful life, together. Cheers to you both."

ps: Most of the last paragraph, I have 'borrowed' from the movie Wedding Crashers. The rest, I have written myself.