Older blog entries for bagder (starting at number 803)

HTTPbis design team meeting London

I’m writing this just hours after the HTTPbis design team meeting in London 2014 has ended.

Around 30 people attended the meeting i Mozilla’s central London office. The fridge was filled up with drinks, the shelves were full of snacks and goodies. The day could begin. This is the Saturday after the IETF89 week so most people attending had already spent the whole or parts of the week before here in London doing other HTTP and network related work. The HTTPbis sessions at the IETF itself were productive and had already pushed us forward.

We started at 9:30 and we quickly got to work. Mark Nottingham guided us through the day with usual efficiency.

We all basically hang out in a huge room, some in chairs, some in sofas and a bunch of people on the floor or just standing up. We had mikes passed around and the http2 discussions were flowing back and forth depending on the topics and what people felt about them. Some of the issues that were nailed down this time and will end up detailed in the upcoming draft-11 are (strictly speaking, we only discussed the things and formed opinions, as by IETF guidelines we can’t decide things on an offline meeting like this):

  • Priories of streams will have a dependency graph or direction, making individual  streams less or more important than other
  • A client can send headers without compression and tell the proxy that the header shouldn’t be compressed – used a way to mitigate some of the compression security problems
  • There will be no TLS renegotiation allowed mid-session. Basically a client will have to tear down the connection and negotiate again if suddenly a need to use a client certificate arises.
  • Alt-Svc is the way forward so ALTSVC will appear a new frame in draft-11. This is the way to signal to an application that there is another “route” tIMG_20140308_100453o the same content on the same server. This will allow for what is popularly known as “opportunistic encryption” or at least one sort of that. In short, you can do “plain-text” HTTP over a TLS connection using this…
  • We decided that a server should support gzip contents from clients

There were some other things too handled, but I believe those are the main changes. When the afternoon started to turn long, beers and other beverages were brought out and we did enjoy a relaxing social finale of the day before we split up in smaller groups and headed out in the busy London night to get dinner…

Thanks everyone for a great day. I also appreciated meeting several people in real-life I never met before, only discussed with and read emails from online and of course some old friends I hadn’t seen in a long time!

Oh, there’s also a new rough time frame for http2 going forward. Nearest in time would be the draft-11 at the end of March and another interim in the beginning of June (Boston?).

As a reminder, here’s what was happened for draft-10, and here is http2 draft-10.

Out of all people present today, I believe Mozilla was the company with the largest team (8 attendees) – funnily enough none of us Mozillians there actually work in this office or even in this country.

Syndicated 2014-03-08 21:03:55 from daniel.haxx.se

A payment on a flight story

“Three beers and three chicken sandwiches, thanks” – I said, graciously handing over my VISA card to the flight stewardess to pay for everything for me and my two Haxx friends Björn and Linus. 20 something Euros. Neither of us were carrying any cash.

We were happy that we had seats in the 7th row on the way back to Stockholm since when we flew down to FOSDEM Brussels just two days earlier we were in the 18th row and by then they had ran out of sandwiches. Brussels Airlines on a direct flight.

The lady inserted the card into her handheld card-reader, messed around a while since it wouldn’t “take” at the first attempt and then she handed it to me to enter my PIN. So I did.

credit cardsMs stewardess pressed some buttons or something and then she said, “no it doesn’t work” and continued to try inserting my card in basically every variation you can (especially having the chip side turned out has to be a very clever way) while repeating to me that it doesn’t work. This is the same card I’ve used numerous times during the weekend and I used it several times at the airport less than an hour ago. I know it works.

“OK let’s say you’re right”, I sighed as I really didn’t think I nor my card were to blame but I also didn’t feel like just causing trouble. I handed her my second VISA card. “Here, try this instead then”.

“No it doesn’t work either”. This certainly wasn’t right.

Linus reached over and offered his MasterCard. Perhaps there was a VISA problem with the device but “Sorry sir, it doesn’t work” came back. We’re now at farce level. Björn joins the fun and offers a 4th card, another MasterCard.

By this time we’ve eaten most of the sandwiches and were enjoying the beers.

The lady continued to struggle and it still didn’t work. She was starting to act a bit troubled about this and I asked her if she really insisted that all our cards are broken and she admitted that she suspected the machine wasn’t working quite as it should. Then she leaned towards the male steward who was serving drinks a couple of steps away. They fiddled a bit more and then she came back to us.

“That worked, I swiped it” she said without much further explanation and returned with Björn’s card and the receipt for the purchase. I felt quite done with this by now so I didn’t ask nor pushed her why she didn’t do that earlier. I was glad it finally was fixed. So much for me paying, now Björn did it instead. Oh well, truly fascinating that they would do like this on an airline where people have to do purchases with credit cards all the time.

Then Björn looked at the receipt he got back:

Pringles and a bottle of water, 5 Euro.

It made all three of us burst out in uncontrolled laughter. It was then followed by some contemplation what it actually meant. What exactly did Björn pay for? Did he only get the wrong receipt or did he pay for it? If so, who paid for our food and drinks?

It is 2014 and we haven’t come further than this.

(Update: Björn reminded me that we did verify the last 4 digits of the card number on the receipt and it didn’t match any of our cards…)

Syndicated 2014-02-03 13:21:38 from daniel.haxx.se

My FOSDEM 2014

I’m back home after FOSDEM 2014.Lots of coffee A big THANK YOU from me to the organizers of this fine and totally free happening.

Europe’s (the World’s?) biggest open source conference felt even bigger and more crowded this year. There seemed to be more talks that got full, longer lines for food and a worse parking situation.

Nothing of that caused any major concern for me though. I had a great weekend and I met up with a whole busload of friends from all over. Many of them I only meet at FOSDEM. This year I had some additional bonuses by for example meeting up with long-term committers Steve and Dan from the curl project whom I had never met before IRL. Old buddies from Haxx and Rockbox are kind of default! :-)

Talk-wise this year was also extra good. I’ve always had a soft spot for the Embedded room but this year there was fierce competition for my attention so I spread my time among many rooms and got to see stuff about: clang the compiler, lots of really cool stuff on GDB, valgrind and helgrind, power efficient software, using the GPU to accelerate libreoffice, car automation and open source, how to run Android on low-memory devices, Firefox on Android and more.

I missed out the kdbus talks since it took place in one of them smaller devrooms even though it was “celebrity warning” all over it with Lennart Poettering. In general there’s sometimes this problem at FOSDEM that devrooms have very varying degrees of popularity on the different talks so the size of the room may be too large or too small depending on the separate topics and speakers. But yeah, I understand it is a very hard problem to improve for the organizers.

As a newbie Firefox developer at Mozilla I find it fun to first hear the Firefox on Android talk for an overview on how things  run on that platform now and then I also got references to Firefox both in the helgrind talk and the low-memory Android talk. In both negative and positive senses.

As always on FOSDEM some talks are not super good and we get unprepared speakers who talks silently, monotone and uninspired but then there’s the awesome people that in spite of accents and the problem of speaking in English as your non-native language can deliver inspiring and enticing talks that make me just want to immediately run home and try out new things.

The picture on the right is a small tribute to the drinks we could consume to get our spirits up during a talk we perhaps didn’t find the most interesting…

This year I found the helgrind and the gdb-valgrind talks to be especially good together with Meeks’ talk on using the GPU for libreoffice. We generally found that the wifi setup was better than ever before and worked basically all the time.

Accordingly, there were 8333 unique MAC addresses used on the network through the two days, which we then can use to guesstimate the number of attendees. Quite possibly upwards 6000…

See you at FOSDEM 2015. I think I’ll set myself up to talk about something then. I didn’t do any this year.

Syndicated 2014-02-03 08:34:07 from daniel.haxx.se

HTTP2 – the next step

IETFThe HTTPbis working group of the IETF had an interim meeting in Zurich January 22nd to 24th. I participated from remote and I listened in on the discussions over webex and followed the jabber room while the meetings were going on, addressing HTTP2 protocol issues one by one ironing out quirks and progressing forward.

I won’t bore you with details why I wasn’t present in Zurich.

Here’s a couple of quick and brief reflections from my perspective:

Listening in from remote like this is not at all adequately compensating for not being there. A room full of people discussing something is really hard to follow from remote and completely impossible to interact with. It is better than not being able to listen in at all, but it is certainly not a replacement for being there.

It is amazing how much faster people can come to conclusions and fix issues when being in the same room. Issues that have been lingering in the tracker for a very long time could be dealt with and closed within minutes. Things like what to call the protocol in ALPN or to remove the ability to switched off flow control. Not all issues of course…

HTTP2 draft-09 that soon will become draft-10 to reflect the updates from this meeting and more, is from my perspective quite far in its process. It is clearly at a point that seems to be OK with most people and the discussions are now just about details. Of course the devil is in the details and I’m not saying it can’t take a long time to settle on them, but the structure and main concepts of the protocol are probably now established.

There were not very many proxy or server people at the interim. Most of the people seemed to be client-side oriented and some service oriented. I’m personally client-side biased myself but I hope this doesn’t lead to us deciding on things that the “other side” will have problems with down the line.

Firefox nightly supports HTTP2 draft-09 (for https:// URLs) and twitter supports it server side. Enable it in the browser by entering “about:config” in the URL bar and change the config entry called “network.http.spdy.enabled.http2draft” to true. Done.

Some of the biggest HTTP2 changes brought up compared to what draft-09 says include:

  • no more ability to switch off flow control
  • the prioritization field/concept “weighted dependency tree approach”
  • >= TLS 1.2 with ephemeral ciphers
  • MUST not use TLS compression
  • tolerant to TLS false start or at least must accept/buffer application layer data
  • padding

There was also a whole lot of discussions about TLS for http:// urls, proxys, MITM for SSL, opportunistic encryption and more but I believe most of those issues remained at the same position as before – I missed out on parts of the last afternoon so I may have missed some details. It’ll all be revealed in draft-10 and the mailing list I’m sure!


Syndicated 2014-01-24 21:40:08 from daniel.haxx.se

My first Mozilla week

Working from home

I get up in the morning, shave, eat breakfast and make sure all family members get off as they should. Most days I walk my son to school (some 800 meters) and then back again. When they’re all gone, the house is quiet and then me and my cup of coffee go upstairs and my work day begins.

Systems and accounts

I have spent time this week to setup accounts and sign up for various lists and services. Created profiles, uploaded pictures, confirmed passwords. I’ve submitted stuff and I’ve signed things. There’s quite a lot of systems in use.

My colleagues

I’ve met a few. The Necko team isn’t very big but the entire company is huge and there are just so many people and names. I haven’t yet had any pressing reason to meet a lot of people nor learn a lot of names. I feel like I’m starting out this really slowly and gradually.

Code base

Firefox is a large chunk of code. It takes some 20 minutes to rebuild on my 3.5GHz quad-core Core-i7 with SSD. I try to pull code and rebuild every morning now so that I can dogfood and live on the edge. I also have a bunch of local patches now, some of them which I want to have stewing in my own browser for a while so that I know they at least don’t have any major negative impact!

Figuring out the threading, XPCOM, the JavaScript stuff and everything is a massive task. I really cannot claim to have done more than just scratched the surface so far, but at least I am scratching and I’ve “etagged” the whole lot and I’ve spent some time reading and reviewing code. Attaching a gdb to a running Firefox and checking out behavior and how it looks has also helped.

Netwerk code size

“Netwerk” is the directory name of the source tree where most of the network code is located. It is actually not so ridiculously large as one could fear. Counting only C++ and header files, it sums up to about 220K lines of code. Of course not everything interesting is in this tree, but still. Not mindbogglingly large.

Video conferencing

I’ll admit I’ve not participated in this sort of large scale video conferences before this. Wiith Vidyo and all the different people and offices signed up at once – it is a quite impressive setup actually. My only annoyance so far is that I didn’t get the sound for Vidyo to work for me in Linux with my headphones. The other end could hear me but I couldn’t hear them! I had to defer to using Vidyo on a windows laptop instead.

Doing the video conferencing on a laptop instead of on my desktop machine has its advantages when I do them during the evenings when the rest of the family is at home since then I can move my machine somewhere and sit down somewhere where they won’t disturb me and I won’t disturb them.


The bug tracker is really in the center for this project, or at least for how I view it and work with it right now. During my first week I’ve so far filed two bug reports and I’ve submitted a suggested patch for a third bug. One of my bugs (Bug 959100 – ParseChunkRemaining doesn’t detect chunk size overflow) has been reviewed fine and is now hopefully about to be committed.

I’ve requested commit access (#961018) as a “level 1″ and I’ve signed the committer’s agreement. Level 1 is entry level and only lets me push to the Try server but still, I fully accept that there’s a process to follow and I’m in no hurry. I’ll get to level 3 soon enough I’m sure.


What can I say. After having used it a bit this week without any particularly fancy operations, I prefer git so much more. Of course I’m also much more used to git, but I find that for a lot of the stuff where both have similar concepts I prefer to git way. Oh well, its just a tool. I’ll get around. Possibly I’ll try out the git mirror soon and see if that provides a more convenient environment for me.


What impact did all this new protocol and network code stuff during my work days have on my curl activities?

I got inspired to fix both the chunked encoding parser and the cookie parser’s handling of max-age in libcurl.

What didn’t happen

I feel behind in the implementing-http2 department. I didn’t get my new work laptop yet.

Next weekDaniel's work place

More of the same, land more patches and figure out more code. Grab more smallish bugs others have filed and work on fixing them as more practice.

Also, there’s a HTTPbis meeting in Zürich on Wednesday to Friday that I won’t go to (I’ll spare you the explanation why) but I’ll try to participate remotely.

Syndicated 2014-01-17 15:34:53 from daniel.haxx.se

My commute

Just in case you missed my youtube/G+ posting from yesterday about my new trip to work:

Syndicated 2013-11-27 18:56:07 from daniel.haxx.se

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