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").
The 'bad tracker' penalty was introduced in 2009 after a top tier trackers went down. Announces to it would hang, tying up an announce slot in libcurl for minutes at a time. If a user had enough torrents from that tracker, it could bottleneck all announce slots. The workaround was to deprioritize failing trackers so that they wouldn't obstruct other trackers.
Its implementation could be better, however. There are two parts:
1. Deciding how frequently to retry unresponsive trackers
2. Once an unresponsive tracker announce was ready to go, it would be bumped down the queue if other announces were ready too.
Part 2 probably contributes to #3931. If there are enough torrents loaded, there will always be good tracker announces that get pushed ahead of a bad one in the queue. Modifying 2's heuristics would be one option, but it seems simpler to remove it altogether now that getRetryInterval() grades more hashly for consecutive failures. Altering the retry interval also gives better visual feedback to users than Part 2 did.
This commit removes "Part 2" as described above.
jusid reports that powl() doesn't exist on uClibc, so getRetryInterval() needs to work without it. A simple left-bit shifting would be fine, but since we max out after a handful of cases, a switch statement seems slightly more readable than shifting or powl().
Use tor->isRunning, rather than tier->isRunning, when testing to see if a torrent can manual announce or not. tor->isRunning means we're inbetween the user pressing "start" and "stop." tier->isRunning means we're inbetween successful "started" and "stopped" announcements. (This is deliberately out-of-sync from tor->isRunning because it can take awhile to for tracker announces to finish.)
Under the old code (using tier->isRunning), it was impossible to manually reannounce unless there had been a successful event=started announce first. It was also possible to manually announce after the "stop" button had been pressed if the "event=stopped" announcement hadn't finished yet.
Remove redundant code by using tr_peerMgrCompactToPex() and tr_peerMgrCompact6ToPex() to parse compact ipv4 and ipv6 peer lists. Simplify the old-style benc peer list parsing and fix a bug that returned too few bytes in the old-style peer array.
The exponentially-growing interval between retries had a bug that caused intervals to be too long if no successful announce had ever been made. This commit fixes the code that calculates the interval.
The Berne Convention says that the copyright year is moot, so instead of adding another year to each file as in previous years, I've removed the year altogether from the source code comments in libtransmission, gtk, qt, utils, daemon, and cli.
Juliusz's copyright notice in tr-dht and Johannes' copyright notice in tr-lpd have been left alone; it didn't seem appropriate to modify them.
In some cases we were calling them from deep inside libtransmission, when they should have been called directly from the public-visible API functions: tr_torrentWebSpeeds_KBps(), tr_torrentPeers(), tr_torrentTrackers().
