This should cause uTP sockets to respect read bandwidth limits. I'm not so
sure about the values we return for the read buffer size -- perhaps we
should allow some slack for network latency?
There's no need to test for DHT/uTP being enabled in tr-udp. The DHT
will silently discard any packets directed at the wrong session (see the
beginning of dhtCallback). As to uTP, we need to grok uTP packets
to close any remaining connections after we disabled uTP, so it's better
to participate in uTP, just reject any incoming connections.
Libutp will sometimes call our callbacks after we called UTP_Close,
notably to notify us of the UTP_STATE_DESTROYING state change, but
also, for some reason, to ask us about our read buffer. The simplest
way to avoid issues with that is to switch to a second set of callbacks.
This adds code to participate in the UTP protocol, but without doing anything
useful yet -- we just shut down immediately any incoming connexion request.
This commit, started by a patch from athy, implements a rarest first policy when deciding which pieces to request from peers. It keeps a count of how many peers have each piece, and updates the count when getting bitfields, have, have all, and have none messages, as well as decrementing the counts when peers disconnect.
This running total is generated only for downloading torrents. Seeds don't have this overhead.
This patch adds two new flags to the callback function -- did_connect and did_timeout -- that are calculated inside of web.c using information from libcurl. This allows the announcer to detect timeouts more accurately and also to distinguish between unresponsive peers (which get the preexisting "Tracker did not respond" error message) and unconnectable peers (which get a new error message, "Could not connect to tracker").
We now try to contact the bootstrap nodes up to six times.
A better solution might be to reattempt bootstrap every half hour
or so. This might be beneficial to people whose connectivity
changes while Transmission is running.
