Category Archives: Development

cURL and libcurl, Development

curl meetup at Fosdem 2012

The FOSDEM 2012 dates were recently revealed (4-5 February 2012).

A pint of guinness

I’d be happy to arrange a get-together for libcurl hackers at Fosdem this year. To me, Brussels, Belgium seems mid-europe enough to be able to attract a bunch of us:

  • libcurl application users/authors
  • libcurl binding hackers
  • libcurl contributors
  • … and everyone else who’s doing related activities or who just is interested

Potential subjects to discuss at such a meeting:

  • what’s the most important stuff libcurl still lacks?
  • what’s the least documented/understood parts of libcurl?
  • are there shared problems several/many libcurl bindings have to solve?
  • can we improve how we work/develop libcurl and bindings?
  • what kind of beer is best at a curl meetup?
  • [fill in your own curl related subject]

I would like at least 4-5 people voicing interest for this to be worthwhile for me to actually try to do anything. Please speak up on the libcurl mailing list, tweet me or mail me privately! The more people that are interested, the more planning and stuff we’ll do for it.

Development, Technology

Haxx – the first year

Last year I left my former employment, and focused on Haxx full-time. My brother joined me a few months afterward (January 2010). Today, at October 1 2010 we celebrate the official one year anniversary of Haxx AB as employer.Haxx

The history of Haxx goes far longer back than so. Linus Nielsen Feltzing and I first registered the company Haxx back in October 1997 and we used it then primarily as a way to market and do business on the side of our “real” jobs. To have a way to charge and do things we wanted to, that wasn’t conflicting with our day jobs. And of course we also bought the domain and could setup our “permanent” email addresses etc, which turned out great since I’ve thus used the same email address since back then and I hope I never need to change it again!

The first year of Haxx has been nothing but great fun and a major success.

As we’re contract developers and consultants, we of course need to make sure that our employees are sold to customers to a high degree with as little gaps as possible. Our projects are typically going on from a few months up to a year or two. During this year, both me and Björn have worked with several end customers and we’ve thus both managed to change assignments several times and none of the times caused any gaps – at all. Our services seem to be in high demand.

Being only two employees brings challenges on how to deal with sales, financial accounting etc as we’re just a few guys and we’re experts on development! We have found a few great partners that “sell” us (and of course we pay them a certain amount of percentage, but that’s a price we need to accept and is nothing but fair anyway since we can then remain doing what we’re good at and what we love) and we’re buying the bookkeeping etc from another company that is specialized at doing it for companies like us.

We’re looking forward to many more years of great fun. We also hope to be able to grow the company slightly over time, so if you’re a kick-ass embedded open source guy with networking experience and some 10+ years in the business and you live in the Stockholm Sweden area, do get in touch! As I’ve mentioned before, we’re gonna start out our second year with Linus onboard.

I’ll get back with an update next year! 🙂

Development, Rockbox

Haxx gets Linus over to the good side

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Linus Nielsen Feltzing and I founded Haxx a long time ago, so therefore it is extra fun to welcome him to join me and Björn to work full-time for our small but already now skill-packed company. Starting December this year, Linus will do all his consultancy and contract work wearing his Haxx hat and no other. Employee number three.

He comes from an employment at the same consultant company I was employed by before (and Björn was too a while ago). With this addition Haxx is now having three full-time consultants with more than 20 years of experience each within software development and embedded systems. We have a long and thorough experience in Linux and networks, in embedded and in larger systems.Haxx

Björn and I originally got to know Linus back in 1988 when we visited a “copy-party” in Alvesta Sweden. There we (the C64 demo group named Horizon) competed against the other teams in the demo competition. We won the competition with our demo “Love This Now” while the fellows in Microsystems Digital Technology (MDT) came at second place with their “Bonanza“.

MDT consisted of two persons, and one of them was Linus.

After Alvesta, Linus and Jörgen (the other MDT member) joined Horizon and we’ve known each other since. We’ve worked on the same companies since the late 90s something until the day last year when I started working full-time for Haxx.

Linus is a hardcore embedded developer, working close to hardware and the OS, writing primarily C and assembler code. He has worked a lot with various RTOSes and Linux.

Linus is also known as one of the founders of the Rockbox project together with me and Björn.

Development, Network

poll vs select

I’m a person working a lot with networking and development around it. I mostly do this on Linux, often involving drivers or otherwise very close to the operating system and C and the core libraries.

The other day I once again fell over some random inaccuracy about poll compared to select and instead of trying to whine on some IRC channel or complain on their mailing list, I decided I would instead strike back by writing up and presenting a web page of my own. It details as much as possible about poll vs select and related event-based functions. I want it to become a placeholder for everything that is relevant to say about poll and select in a comparison aspect and when comparing them to event-based alternatives like libevent and libev.

So the next time I face someone not quite understanding this whole situation or perhaps when someone reiterates something that isn’t quite true, I have a resource to point to.

Not to mention that I think this new poll vs select page fits in nicely with my other “X vs Y” articles and docs pages I’ve written the last few years.

If you find flaws, or miss details or have questions about this page. Please do not hesitate to comment here, or to mail me about it or tweet me on twitter or whatever method you prefer. I appreciate your feedback!

poll vs select

cURL and libcurl, Development, Web

OPTIMERA STHLM

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Our friends at .SE are once again putting together an interesting conference-style day with talks, and this time the title of it is “OPTIMERA STHLM” (yes they use all caps) and it is all about optimizing web-related things.

I’ve been invited and I will do a 30 minute talk during that day about the transport layer and stuff on top of the transport layer. In other words it’ll include things to consider for TCP, DNS, HTTP, handling sockets, libcurl and a quick look at things such as Websockets, SPDY, MPTCP and SCTP.

The full day’s program is now available on the linked page. Enjoy!

cURL and libcurl, Development

professional libcurl hackers look this way!

In my company, Haxx, we work as consultants and we do contract development for customers who pay for our skill, time and dedication. We help them develop stuff.Haxx

We’re a small company, with basically two full-time employees. Most of our working days, we are involved with a single customer each who pays for our full-time involvement during a number of months. This is all good and fine. We love our jobs and we love our customers. We’re in it for the fun.

Now, these days we can see that the economy is slowly but surely gaining ground again and is getting up to speed. We hear more and more requests for help and potential assignments are starting to pour in. That’s great and all. Except that we’re only two guys and can’t accept very many projects…

Recently we’ve experienced a noticeable increase in amount of requests for support and other development help that involves curl and libcurl. I am the originator and maintainer of curl, there’s really no surprise or wonder that these companies contact me and us about it. I’m always very happy to see that there are companies and persons who are willing to pay for support of open source and in many cases pay for extending and bug fixing libcurl and have those fixes going back to the mainline sources without complaints.

Since we fail to accept a lot of requests, I’m interested in finding you who are interested in helping out with such work. Are you interested in helping out customers with curl related problems? Customers often come to us when they’ve got stuck within something they can’t easily solve themselves and they turn to us as experts in general, and experts on curl and libcurl in particular. And we are.

Before you think this is a great idea and you send me an email introducing yourself and your greatness in this area, please be aware that I will require proof of your qualifications. Most preferably, that proof is at least one good patch posted to the libcurl mailing list and accepted into the mainline libcurl code, but I’m open to accepting slightly less ideal proofs as well if you can just motivate why you failed to provide the ideal ones. Of course you will also need to be able to communicate in English without problems. Your geographical location, gender, race, religion, skin-color and shoe size are completely uninteresting.

I’m looking for someone interested in contract development, not full-time employment. We still do these kinds of jobs on a case by case basis and there may be one every two days, one per week or sometimes even less frequently. I want to increase my network of people I know and trust can deliver quality code and services for this kind of projects.

Can you help us?

cURL and libcurl, Development, Network

curl and speced cookie order

I just posted this on the curl-library list, but I feel it suits to be mentioned here separately.

As I’ve mentioned before, I’m involved in the IETF http-state working group which is working to document how cookies are used in the wild today. The idea is to create a spec that new implementations can follow and that existing implementations can use to become more interoperable.

(If you’re interested in these matters, I can only urge you to join the http-state mailing list and participate in the discussions.)

The subject of how to order cookies in outgoing HTTP Cookie: headers have been much debated over the recent months and I’ve also blogged about it. Now, the issue has been closed and the decision went quite opposite to my standpoint and now the spec will say that while the servers SHOULD not rely on the order (yeah right, some obviously already do and with this specified like this even more will soon do the same) it will recommend clients to sort the cookies in a given way that is close to the way current Firefox does it[*].

This has the unfortunate side-effect that to become fully compatible with how the browsers do cookies, we will need to sort our cookies a bit more than what we just recently introduced. That in itself really isn’t very hard since once we introduced qsort() it is easy to sort on more/other keys.

The biggest problem we get with this, is that the sorting uses creation time of the cookies. libcurl and curl and others mostly use the Netscape cookie files to store cookies and keep state between invokes, and that file format doesn’t include creation time info! It is a simple text-based file format with TAB-separated columns and the last (7th) column is the cookie’s content.

In order to support the correct sorting between sessions, we need to invent a way to pass on the creation time. My thinking is that we do this in a way that allows older libcurls still understand the file but just not see/understand the creation time, while newer versions will be able to get it. This would be possible by extending the expires field (the 6th) as it is a numerical value that the existing code will parse as a number and it will stop at the first non-digit character. We could easily add a character separation and store the
creation time after. Like:

Old expire time:

2345678

New expire+creation time:

2345678/1234567

This format might even work with other readers of this file format if they do similar assumptions on the data, but the truth is that while we picked the format in the first place to be able to exchange cookies with a well known and well used browser, no current browser uses that format anymore. I assume there are still a bunch of other tools that do, like wget and friends.

Update: as my friend Micah Cowan explains: we can in fact use the order of the cookie file as “creation time” hint and use that as basis for sorting. Then we don’t need to modify the file format. We just need to make sure to store them in time-order… Internally we will need to keep a line number or something per cookie so that we can use that for sorting.

[*] – I believe it sorts on path length, domain length and time of creation, but as soon as the -06 draft goes online it will be easy to read the exact phrasing. The existing -05 draft exists at: http://tools.ietf.org/html/draft-ietf-httpstate-cookie-05

Development, Network, Security

An FTP hash command

9 Comments

Anthony Bryan strikes again. This time his name is attached to a new standards draft for how to get a hash checksum of a given file when using the FTP protocol. draft-bryan-ftp-hash-00 was published just a few days ago.

The idea is basically to introduce a spec for a new command named ‘HASH’ that a client can issue to a server to get a hash checksum for a given file in order to know that the file has the exact same contents you want before you even start downloading it or otherwise consider it for actions.

The spec details how you can ask for different hash algorithms, how the server announces its support for this in its FEAT response etc.

I’ve already provided some initial feedback on this draft, and I’ll try to assist Anthony a bit more to get this draft pushed onwards.

Development

Haxx <<= 1;

Oh yes, I’ve been dreaming of the day when I could use a blog post title with a left shift operator! 😉

HaxxOur growth rate is indeed phenomenal as my brother Björn joins Haxx as employee number two, and we’ve now doubled our size! Well, at least we double the number of full-time Haxxers.

Haxx continues to focus on being highly skilled and experienced consultants within embedded, Linux , networking and open source.

If you need help in your project, or know of anyone else who could use skilled embedded consultants. Give us a beep!

If you, dear readers, are interested in working with or for us, and you think you are a skilled person within one or more of our areas then by all means get in touch! If you’re living and working in Sweden and most preferably in the Stockholm area, it’ll be really cool.

Development

First month on my own

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Yeah, it’s already been a month since I took off and started working for Haxx full time. Starting a company (even though the company already existed in the legal sense) certainly involves a lot of paperwork and talking to banks, insurance companies and getting arrangements with partners etc. A lot of that of course being just an initial phase, but some of it will be a more integrated part of my day now when I don’t have a well-oiled team of admins hired that deal with such matters.

I’m happy to say that I have had a whole slew of good talks with existing and potentially new customers, and I’m already cooperating with a few companies in very constructive ways – so that I can help others succeed with their undertakings. Several things that happened during this month involved open source (although I’m not able to talk about them in public), and I feel really good when my work and my beliefs can go hand in hand!

This said, I’m always ready for more and new missions. If you’re in need, you know where I am!