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Welcome to Remlab.net! This is the home page of Rémi Denis-Courmont.

Who am I?

I am currently working as a Linux kernel and system software engineer for Nokia in Helsinki, Finland. I am also one of the core developpers of the VLC media player at the VideoLAN project, the original developper of Miredo, the Teredo stack for Linux & BSD, and the maintainer of the minisap server and ndisc6 IPv6 utilities.

News

This is not a blog. There is no Atom or RSS feed.

01 February 2009 - the myth of non-blocking I/O

I have had enough of hearing that blocking I/O should never be used (except for debug messages perhaps). This article explains why you should really use normal and simple blocking I/O when dealing with files.

17 June 2008 - DCCP is so convenient

This only works on Linux:

% LOCAL_IP=192.2.0.1
% vlc music/*.mp* --loop --sout \
  "#gather:rtp{proto=dccp,dst=$LOCAL_IP,mux=ts,sap,name=\"DCCP channel\"}"
% vlc -S sap

Nice replacement for multicast, especially on a wireless LAN.

16 June 2008 - VLC 0.9.0 features freeze

The development tree for VLC media player 0.9.0 is finally frozen. We might eventually get a usable release in the near future.

So how long have we been working on 0.9.0? Lets see, 0.8.6 was released in december 2006. One and a half year, then. Or so I thought. But what does git-merge-base have to say about this?

% git-merge-base videolan/master videolan/0.8.6-bugfix
a5dd5b1c1123bc38f2aefd7bad2aa869be65720
% git show a5dd5b1c1123bc38f2aefd7bad2aa869be65720
commit a5dd5b1c1123bc38f2aefd7bad2aa869be657203
Author: Christophe Mutricy
Date:   Fri Apr 14 11:42:49 2006 +0000

So over 2 years afterall... This commit was done back in the time of 0.8.5-test2! Probably every had forgotten that 0.8.6 was initially supposed to be 0.8.5-1, a continuation of the "stable" 0.8.5 branch. No surprise it has become so difficult to maintain the 0.8.6 bugfix-only branch when you consider it is based on such an old mostly unmodified build system and "contribs".

15 June 2008 - Secure RTP

The SRTP library had been in the VLC development tree for over a year. Now it is actually integrated with both the new RTP receiver and the RTP output. Unfortunately, it only supports static keys and no (S)RTCP, but that is a start.

% KEY=123456789ABCEF0123456789ABCEF0123456789ABCEF0123456789ABCEF0
% SALT=123456789ABCDE123456789ABCDE

% # Receiving
% vlc rtp://@239.255.1.2:1234 --srtp-salt $SALT --srtp-key $KEY

% # Sending
% vlc music.mp3 --sout \
"#rtp{dst=239.255.1.2,port-audio=1234,salt=$SALT,key=$KEY}"

Hosted projects

A few of my open-source projects are available here:

Miredo: Teredo for Linux and BSD: Teredo (automatic tunneling of IPv6 through NATs) implementation.
ndisc6, tcptraceroute6, etc: A small collection of IPv6 diagnostic tools including IPv6 replacements of arping (ndisc6) and tcptraceroute (tcptraceroute6).
TCP re-engineering tool: A portable TCP ports forwarder with content logging capabilities.
Web6: Online French language introduction to the IPv6 protocol.

Opinions

Some technical personal opinion (or factual) articles:

Non-blocking I/O with regular files (February 2009)
The pointless sizeof discussion (September 2008)
C integers (September 2008)
Video on Demand: RTSP vs HTTP (February 2008)
Issues with CMake (February 2008)

Publications

UDP-Encapsulated Transport Protocols: IETF Experimental individually-submitted draft.
Network Address Translation (NAT) Behavioral Requirements for DCCP: IETF Best Current Practices working group draft.
Test vectors for STUN: IETF Informational working group draft.
Connection setup negociation for the Message Session Relay Protocol: IETF Experimental individually-submitted draft.
A Survey of Protocols to Control Network Address Translators and Firewalls: IETF Informational individually-submitted draft, co-authored with Lars Eggest, Pasi Sarolahti, Vlad Stirbu & Hannes Tschofenig

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