[Bloat] better tc support for bittorrent/diffserv

[Eric Dumazet]

On Mon, 2012-05-14 at 19:50 +0200, Juliusz Chroboczek wrote:
> [Pro memoria, I'm the author of a few of the networking bits in
> Transmission, notably the DHT, the µTP support and large parts of the
> IPv6 code.]
> 
> > 0) No ecn on transmission, at least.
> 
> TCP flows will use ECN if your system is configured to use ECN.  µTP
> doesn't do ECN, and there's no easy way to implement it -- there's no
> API to set ECN on UDP packets.

There is an API to set ECN on UDP packets.

setsockopt() IP_TOS, with val = 2