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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever. */
/* System */
#include <poll.h>
#include <pthread.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
/* Opentracker */
#include "ot_accesslist.h"
#include "ot_clean.h"
#include "ot_mutex.h"
#include "ot_stats.h"
#include "ot_vector.h"
#include "trackerlogic.h"
/* Returns amount of removed peers */
static ssize_t clean_single_bucket(ot_peer *peers, size_t peer_count, size_t peer_size, time_t timedout, size_t *removed_seeders) {
ot_peer *last_peer, *insert_point;
if (!peer_count)
return 0;
last_peer = peers + peer_count * peer_size;
/* Two scan modes: unless there is one peer removed, just increase ot_peertime */
while (peers < last_peer) {
time_t timediff = timedout + OT_PEERTIME(peers, peer_size);
if (timediff >= OT_PEER_TIMEOUT)
break;
OT_PEERTIME(peers, peer_size) = timediff;
peers += peer_size;
}
/* If we at least remove one peer, we have to copy */
for (insert_point = peers; peers < last_peer; peers += peer_size) {
time_t timediff = timedout + OT_PEERTIME(peers, peer_size);
if (timediff < OT_PEER_TIMEOUT) {
OT_PEERTIME(peers, peer_size) = timediff;
memcpy(insert_point, peers, peer_size);
insert_point += peer_size;
} else if (OT_PEERFLAG_D(peers, peer_size) & PEER_FLAG_SEEDING)
(*removed_seeders)++;
}
return (peers - insert_point) / peer_size;
}
/* Age one family's peers by timedout minutes. Frees the list and clears the
slot once its last peer is gone, so an absent family costs nothing. */
static void clean_peer_list_family(ot_peerlist **slot, size_t peer_size, ot_time timedout) {
ot_peerlist *peer_list = *slot;
ot_vector *peer_vector;
size_t num_buckets = 1, removed_seeders = 0;
if (!peer_list)
return;
peer_vector = &peer_list->peers;
if (OT_PEERLIST_HASBUCKETS(peer_list)) {
num_buckets = peer_vector->size;
peer_vector = (ot_vector *)peer_vector->data;
}
while (num_buckets--) {
size_t removed_peers = clean_single_bucket(peer_vector->data, peer_vector->size, peer_size, timedout, &removed_seeders);
peer_list->peer_count -= removed_peers;
peer_vector->size -= removed_peers;
if (removed_peers)
vector_fixup_peers(peer_vector, peer_size);
/* Skip to next bucket, a vector containing peers */
++peer_vector;
}
peer_list->seed_count -= removed_seeders;
if (!peer_list->peer_count) {
free_peerlist(peer_list);
*slot = NULL;
return;
}
/* See if we need to convert the list from simple vector to bucket list */
if ((peer_list->peer_count > OT_PEER_BUCKET_MINCOUNT) || OT_PEERLIST_HASBUCKETS(peer_list))
vector_redistribute_buckets(peer_list, peer_size);
}
/* Clean a single torrent
return 1 if torrent timed out
*/
int clean_single_torrent(ot_torrent *torrent) {
ot_time timedout = time_since_minutes(torrent->base);
/* Touched since the last sweep: nothing to do */
if (!timedout)
return 0;
/* Torrent has idled out */
if (timedout > OT_TORRENT_TIMEOUT)
return 1;
/* Already empty and nothing arrived before the peer timeout: keep it only
while a down count is worth remembering */
if (timedout > OT_PEER_TIMEOUT && !torrent->peer_list6 && !torrent->peer_list4)
return torrent->down_count ? 0 : 1;
/* Peers past the peer timeout are gone regardless, which caps how far the
lists are aged in this pass */
if (timedout > OT_PEER_TIMEOUT)
timedout = OT_PEER_TIMEOUT;
clean_peer_list_family(&torrent->peer_list6, OT_PEER_SIZE6, timedout);
clean_peer_list_family(&torrent->peer_list4, OT_PEER_SIZE4, timedout);
if (torrent->peer_list6 || torrent->peer_list4)
torrent->base = time_now_minutes(); /* still carrying peers */
else {
/* Fell empty: hold base a peer timeout back so a later idle sweep makes
the keep-or-drop decision above */
ot_time now = time_now_minutes();
torrent->base = now > OT_PEER_TIMEOUT ? (uint32_t)(now - OT_PEER_TIMEOUT) : 0;
}
return 0;
}
/* Written to once, by clean_deinit, and never read: the byte stays in and
every sleep after it returns at once */
static int g_clean_pipe[2] = {-1, -1};
static void clean_sleep(void) {
struct pollfd pfd;
pfd.fd = g_clean_pipe[0];
pfd.events = POLLIN;
pfd.revents = 0;
poll(&pfd, 1, OT_CLEAN_SLEEP / 1000);
}
/* Clean up all peers in one bucket, remove timedout pools and torrents */
static void clean_bucket(size_t bucket) {
ot_vector *torrents_list = mutex_bucket_lock((int)bucket);
size_t toffs;
int delta_torrentcount = 0;
for (toffs = 0; toffs < torrents_list->size; ++toffs) {
ot_torrent *torrent = ((ot_torrent *)(torrents_list->data)) + toffs;
if (clean_single_torrent(torrent)) {
vector_remove_torrent(torrents_list, torrent);
--delta_torrentcount;
--toffs;
}
}
mutex_bucket_unlock((int)bucket, delta_torrentcount);
}
static void *clean_worker(void *args) {
(void)args;
while (1) {
size_t bucket = OT_BUCKET_COUNT;
while (bucket) {
size_t todo = bucket < OT_CLEAN_BUCKETS_PER_WAKE ? bucket : OT_CLEAN_BUCKETS_PER_WAKE;
/* One bucket is locked at a time, however many a wake gets through */
while (todo--)
clean_bucket(--bucket);
if (!g_opentracker_running)
return NULL;
clean_sleep();
}
stats_cleanup();
#ifdef WANT_ACCESSLIST
accesslist_cleanup();
#endif
}
return NULL;
}
static pthread_t thread_id;
void clean_init(void) {
if (pipe(g_clean_pipe) == -1)
fprintf(stderr, "Warning: the cleaner has no pipe to be woken through and will take up to one sleep interval to stop.\n");
pthread_create(&thread_id, NULL, clean_worker, NULL);
}
void clean_deinit(void) {
const char byte = 0;
(void)!write(g_clean_pipe[1], &byte, 1);
pthread_join(thread_id, NULL);
close(g_clean_pipe[0]);
close(g_clean_pipe[1]);
}
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