opentracker – An open and free bittorrent tracker
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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever.
$id$ */
/* System */
#include <sys/types.h>
#include <sys/uio.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
/* Libowfat */
#include "socket.h"
#include "ndelay.h"
#include "byte.h"
#include "ip6.h"
/* Opentracker */
#include "trackerlogic.h"
#include "ot_livesync.h"
#include "ot_accesslist.h"
#include "ot_stats.h"
#include "ot_mutex.h"
#ifdef WANT_SYNC_LIVE
char groupip_1[4] = { 224,0,23,5 };
#define LIVESYNC_INCOMING_BUFFSIZE (256*256)
#define LIVESYNC_OUTGOING_BUFFSIZE_PEERS 1504
#define LIVESYNC_OUTGOING_WATERMARK_PEERS (sizeof(ot_peer)+sizeof(ot_hash))
#ifdef WANT_SYNC_SCRAPE
#define LIVESYNC_OUTGOING_BUFFSIZE_SCRAPE 1504
#define LIVESYNC_OUTGOING_WATERMARK_SCRAPE (sizeof(ot_hash)+sizeof(uint64_t)+sizeof(uint32_t))
#define LIVESYNC_OUTGOING_MAXPACKETS_SCRAPE 100
#define LIVESYNC_FIRST_BEACON_DELAY (30*60) /* seconds */
#define LIVESYNC_BEACON_INTERVAL 60 /* seconds */
#define LIVESYNC_INQUIRE_THRESH 0.75
#endif /* WANT_SYNC_SCRAPE */
#define LIVESYNC_MAXDELAY 15 /* seconds */
enum { OT_SYNC_PEER
#ifdef WANT_SYNC_SCRAPE
, OT_SYNC_SCRAPE_BEACON, OT_SYNC_SCRAPE_INQUIRE, OT_SYNC_SCRAPE_TELL
#endif
};
/* Forward declaration */
static void * livesync_worker( void * args );
/* For outgoing packets */
static int64 g_socket_in = -1;
/* For incoming packets */
static int64 g_socket_out = -1;
static uint8_t g_inbuffer[LIVESYNC_INCOMING_BUFFSIZE];
static uint8_t g_peerbuffer_start[LIVESYNC_OUTGOING_BUFFSIZE_PEERS];
static uint8_t *g_peerbuffer_pos;
static uint8_t *g_peerbuffer_highwater = g_peerbuffer_start + LIVESYNC_OUTGOING_BUFFSIZE_PEERS - LIVESYNC_OUTGOING_WATERMARK_PEERS;
static ot_time g_next_packet_time;
#ifdef WANT_SYNC_SCRAPE
/* Live sync scrape buffers, states and timers */
static ot_time g_next_beacon_time;
static ot_time g_next_inquire_time;
static uint8_t g_scrapebuffer_start[LIVESYNC_OUTGOING_BUFFSIZE_SCRAPE];
static uint8_t *g_scrapebuffer_pos;
static uint8_t *g_scrapebuffer_highwater = g_scrapebuffer_start + LIVESYNC_OUTGOING_BUFFSIZE_SCRAPE - LIVESYNC_OUTGOING_WATERMARK_SCRAPE;
static size_t g_inquire_remote_count;
static uint32_t g_inquire_remote_host;
static int g_inquire_inprogress;
static int g_inquire_bucket;
#endif /* WANT_SYNC_SCRAPE */
static pthread_t thread_id;
void livesync_init( ) {
if( g_socket_in == -1 )
exerr( "No socket address for live sync specified." );
/* Prepare outgoing peers buffer */
g_peerbuffer_pos = g_peerbuffer_start;
memcpy( g_peerbuffer_pos, &g_tracker_id, sizeof( g_tracker_id ) );
uint32_pack_big( (char*)g_peerbuffer_pos + sizeof( g_tracker_id ), OT_SYNC_PEER);
g_peerbuffer_pos += sizeof( g_tracker_id ) + sizeof( uint32_t);
#ifdef WANT_SYNC_SCRAPE
/* Prepare outgoing scrape buffer */
g_scrapebuffer_pos = g_scrapebuffer_start;
memcpy( g_scrapebuffer_pos, &g_tracker_id, sizeof( g_tracker_id ) );
uint32_pack_big( (char*)g_scrapebuffer_pos + sizeof( g_tracker_id ), OT_SYNC_SCRAPE_TELL);
g_scrapebuffer_pos += sizeof( g_tracker_id ) + sizeof( uint32_t);
/* Wind up timers for inquires */
g_next_beacon_time = g_now_seconds + LIVESYNC_FIRST_BEACON_DELAY;
#endif /* WANT_SYNC_SCRAPE */
g_next_packet_time = g_now_seconds + LIVESYNC_MAXDELAY;
pthread_create( &thread_id, NULL, livesync_worker, NULL );
}
void livesync_deinit() {
if( g_socket_in != -1 )
close( g_socket_in );
if( g_socket_out != -1 )
close( g_socket_out );
pthread_cancel( thread_id );
}
void livesync_bind_mcast( ot_ip6 ip, uint16_t port) {
char tmpip[4] = {0,0,0,0};
char *v4ip;
if( !ip6_isv4mapped(ip))
exerr("v6 mcast support not yet available.");
v4ip = ip+12;
if( g_socket_in != -1 )
exerr("Error: Livesync listen ip specified twice.");
if( ( g_socket_in = socket_udp4( )) < 0)
exerr("Error: Cant create live sync incoming socket." );
ndelay_off(g_socket_in);
if( socket_bind4_reuse( g_socket_in, tmpip, port ) == -1 )
exerr("Error: Cant bind live sync incoming socket." );
if( socket_mcjoin4( g_socket_in, groupip_1, v4ip ) )
exerr("Error: Cant make live sync incoming socket join mcast group.");
if( ( g_socket_out = socket_udp4()) < 0)
exerr("Error: Cant create live sync outgoing socket." );
if( socket_bind4_reuse( g_socket_out, v4ip, port ) == -1 )
exerr("Error: Cant bind live sync outgoing socket." );
socket_mcttl4(g_socket_out, 1);
socket_mcloop4(g_socket_out, 0);
}
static void livesync_issue_peersync( ) {
socket_send4(g_socket_out, (char*)g_peerbuffer_start, g_peerbuffer_pos - g_peerbuffer_start,
groupip_1, LIVESYNC_PORT);
g_peerbuffer_pos = g_peerbuffer_start + sizeof( g_tracker_id ) + sizeof( uint32_t );
g_next_packet_time = g_now_seconds + LIVESYNC_MAXDELAY;
}
static void livesync_handle_peersync( ssize_t datalen ) {
int off = sizeof( g_tracker_id ) + sizeof( uint32_t );
/* Now basic sanity checks have been done on the live sync packet
We might add more testing and logging. */
while( off + (ssize_t)sizeof( ot_hash ) + (ssize_t)sizeof( ot_peer ) <= datalen ) {
ot_peer *peer = (ot_peer*)(g_inbuffer + off + sizeof(ot_hash));
ot_hash *hash = (ot_hash*)(g_inbuffer + off);
if( !g_opentracker_running ) return;
if( OT_PEERFLAG(peer) & PEER_FLAG_STOPPED )
remove_peer_from_torrent( *hash, peer, NULL, FLAG_MCA );
else
add_peer_to_torrent( *hash, peer, FLAG_MCA );
off += sizeof( ot_hash ) + sizeof( ot_peer );
}
stats_issue_event(EVENT_SYNC, 0, datalen / ((ssize_t)sizeof( ot_hash ) + (ssize_t)sizeof( ot_peer )));
}
#ifdef WANT_SYNC_SCRAPE
void livesync_issue_beacon( ) {
size_t torrent_count = mutex_get_torrent_count();
uint8_t beacon[ sizeof(g_tracker_id) + sizeof(uint32_t) + sizeof( uint64_t ) ];
memcpy( beacon, &g_tracker_id, sizeof( g_tracker_id ) );
uint32_pack_big( (char*)beacon + sizeof( g_tracker_id ), OT_SYNC_SCRAPE_BEACON);
uint32_pack_big( (char*)beacon + sizeof( g_tracker_id ) + sizeof(uint32_t), (uint32_t)((uint64_t)(torrent_count)>>32) );
uint32_pack_big( (char*)beacon + sizeof( g_tracker_id ) + 2 * sizeof(uint32_t), (uint32_t)torrent_count );
socket_send4(g_socket_out, (char*)beacon, sizeof(beacon), groupip_1, LIVESYNC_PORT);
}
void livesync_handle_beacon( ssize_t datalen ) {
size_t torrent_count_local, torrent_count_remote;
if( datalen != sizeof(g_tracker_id) + sizeof(uint32_t) + sizeof( uint64_t ) )
return;
torrent_count_local = mutex_get_torrent_count();
torrent_count_remote = (size_t)(((uint64_t)uint32_read_big((char*)g_inbuffer+sizeof( g_tracker_id ) + sizeof(uint32_t))) << 32);
torrent_count_remote |= (size_t)uint32_read_big((char*)g_inbuffer+sizeof( g_tracker_id ) + 2 * sizeof(uint32_t));
/* Empty tracker is useless */
if( !torrent_count_remote ) return;
if( ((double)torrent_count_local ) / ((double)torrent_count_remote) < LIVESYNC_INQUIRE_THRESH) {
if( !g_next_inquire_time ) {
g_next_inquire_time = g_now_seconds + 2 * LIVESYNC_BEACON_INTERVAL;
g_inquire_remote_count = 0;
}
if( torrent_count_remote > g_inquire_remote_count ) {
g_inquire_remote_count = torrent_count_remote;
memcpy( &g_inquire_remote_host, g_inbuffer, sizeof( g_tracker_id ) );
}
}
}
void livesync_issue_inquire( ) {
uint8_t inquire[ sizeof(g_tracker_id) + sizeof(uint32_t) + sizeof(g_tracker_id)];
memcpy( inquire, &g_tracker_id, sizeof( g_tracker_id ) );
uint32_pack_big( (char*)inquire + sizeof( g_tracker_id ), OT_SYNC_SCRAPE_INQUIRE);
memcpy( inquire + sizeof(g_tracker_id) + sizeof(uint32_t), &g_inquire_remote_host, sizeof( g_tracker_id ) );
socket_send4(g_socket_out, (char*)inquire, sizeof(inquire), groupip_1, LIVESYNC_PORT);
}
void livesync_handle_inquire( ssize_t datalen ) {
if( datalen != sizeof(g_tracker_id) + sizeof(uint32_t) + sizeof(g_tracker_id) )
return;
/* If it isn't us, they're inquiring, ignore inquiry */
if( memcmp( &g_tracker_id, g_inbuffer, sizeof( g_tracker_id ) ) )
return;
/* Start scrape tell on next ticker */
if( !g_inquire_inprogress ) {
g_inquire_inprogress = 1;
g_inquire_bucket = 0;
}
}
void livesync_issue_tell( ) {
int packets_to_send = LIVESYNC_OUTGOING_MAXPACKETS_SCRAPE;
while( packets_to_send > 0 && g_inquire_bucket < OT_BUCKET_COUNT ) {
ot_vector *torrents_list = mutex_bucket_lock( g_inquire_bucket );
unsigned int j;
for( j=0; j<torrents_list->size; ++j ) {
ot_torrent *torrent = (ot_torrent*)(torrents_list->data) + j;
memcpy(g_scrapebuffer_pos, torrent->hash, sizeof(ot_hash));
g_scrapebuffer_pos += sizeof(ot_hash);
uint32_pack_big( (char*)g_scrapebuffer_pos , (uint32_t)(g_now_minutes - torrent->peer_list->base ));
uint32_pack_big( (char*)g_scrapebuffer_pos + 4, (uint32_t)((uint64_t)(torrent->peer_list->down_count)>>32) );
uint32_pack_big( (char*)g_scrapebuffer_pos + 8, (uint32_t)torrent->peer_list->down_count );
g_scrapebuffer_pos += 12;
if( g_scrapebuffer_pos >= g_scrapebuffer_highwater ) {
socket_send4(g_socket_out, (char*)g_scrapebuffer_start, g_scrapebuffer_pos - g_scrapebuffer_start, groupip_1, LIVESYNC_PORT);
g_scrapebuffer_pos = g_scrapebuffer_start + sizeof( g_tracker_id ) + sizeof( uint32_t);
--packets_to_send;
}
}
mutex_bucket_unlock( g_inquire_bucket++, 0 );
if( !g_opentracker_running )
return;
}
if( g_inquire_bucket == OT_BUCKET_COUNT ) {
socket_send4(g_socket_out, (char*)g_scrapebuffer_start, g_scrapebuffer_pos - g_scrapebuffer_start, groupip_1, LIVESYNC_PORT);
g_inquire_inprogress = 0;
}
}
void livesync_handle_tell( ssize_t datalen ) {
int off = sizeof( g_tracker_id ) + sizeof( uint32_t );
/* Some instance is in progress of telling. Our inquiry was successful.
Don't ask again until we see next beacon. */
g_next_inquire_time = 0;
/* Don't cause any new inquiries during another tracker's tell */
if( g_next_beacon_time - g_now_seconds < LIVESYNC_BEACON_INTERVAL )
g_next_beacon_time = g_now_seconds + LIVESYNC_BEACON_INTERVAL;
while( off + sizeof(ot_hash) + 12 <= (size_t)datalen ) {
ot_hash *hash = (ot_hash*)(g_inbuffer+off);
ot_vector *torrents_list = mutex_bucket_lock_by_hash(*hash);
size_t down_count_remote;
int exactmatch;
ot_torrent * torrent = vector_find_or_insert(torrents_list, hash, sizeof(ot_hash), OT_HASH_COMPARE_SIZE, &exactmatch);
if( !torrent ) {
mutex_bucket_unlock_by_hash( *hash, 0 );
continue;
}
if( !exactmatch ) {
/* Create a new torrent entry, then */
memcpy( &torrent->hash, hash, sizeof(ot_hash));
if( !( torrent->peer_list = malloc( sizeof (ot_peerlist) ) ) ) {
vector_remove_torrent( torrents_list, torrent );
mutex_bucket_unlock_by_hash( *hash, 0 );
continue;
}
byte_zero( torrent->peer_list, sizeof( ot_peerlist ) );
torrent->peer_list->base = g_now_minutes - uint32_read_big((char*)g_inbuffer+off+sizeof(ot_hash));
}
down_count_remote = (size_t)(((uint64_t)uint32_read_big((char*)g_inbuffer+off+sizeof(ot_hash ) + sizeof(uint32_t))) << 32);
down_count_remote |= (size_t) uint32_read_big((char*)g_inbuffer+off+sizeof(ot_hash ) + 2 * sizeof(uint32_t));
if( down_count_remote > torrent->peer_list->down_count )
torrent->peer_list->down_count = down_count_remote;
/* else
We might think of sending a tell packet, if we have a much larger downloaded count
*/
mutex_bucket_unlock( g_inquire_bucket++, exactmatch?0:1 );
if( !g_opentracker_running )
return;
off += sizeof(ot_hash) + 12;
}
}
#endif /* WANT_SYNC_SCRAPE */
/* Tickle the live sync module from time to time, so no events get
stuck when there's not enough traffic to fill udp packets fast
enough */
void livesync_ticker( ) {
/* livesync_issue_peersync sets g_next_packet_time */
if( g_now_seconds > g_next_packet_time &&
g_peerbuffer_pos > g_peerbuffer_start + sizeof( g_tracker_id ) )
livesync_issue_peersync();
#ifdef WANT_SYNC_SCRAPE
/* Send first beacon after running at least LIVESYNC_FIRST_BEACON_DELAY
seconds and not more often than every LIVESYNC_BEACON_INTERVAL seconds */
if( g_now_seconds > g_next_beacon_time ) {
livesync_issue_beacon( );
g_next_beacon_time = g_now_seconds + LIVESYNC_BEACON_INTERVAL;
}
/* If we're interested in an inquiry and waited long enough to see all
tracker's beacons, go ahead and inquire */
if( g_next_inquire_time && g_now_seconds > g_next_inquire_time ) {
livesync_issue_inquire();
/* If packet gets lost, ask again after LIVESYNC_BEACON_INTERVAL */
g_next_inquire_time = g_now_seconds + LIVESYNC_BEACON_INTERVAL;
}
/* If we're in process of telling, let's tell. */
if( g_inquire_inprogress )
livesync_issue_tell( );
#endif /* WANT_SYNC_SCRAPE */
}
/* Inform live sync about whats going on. */
void livesync_tell( ot_hash const info_hash, const ot_peer * const peer ) {
memcpy( g_peerbuffer_pos, info_hash, sizeof(ot_hash) );
memcpy( g_peerbuffer_pos+sizeof(ot_hash), peer, sizeof(ot_peer) );
g_peerbuffer_pos += sizeof(ot_hash)+sizeof(ot_peer);
if( g_peerbuffer_pos >= g_peerbuffer_highwater )
livesync_issue_peersync();
}
static void * livesync_worker( void * args ) {
ot_ip6 in_ip; uint16_t in_port;
ssize_t datalen;
(void)args;
while( 1 ) {
datalen = socket_recv4(g_socket_in, (char*)g_inbuffer, LIVESYNC_INCOMING_BUFFSIZE, (char*)in_ip, &in_port);
/* Expect at least tracker id and packet type */
if( datalen <= (ssize_t)(sizeof( g_tracker_id ) + sizeof( uint32_t )) )
continue;
if( !accesslist_isblessed(in_ip, OT_PERMISSION_MAY_LIVESYNC))
continue;
if( !memcmp( g_inbuffer, &g_tracker_id, sizeof( g_tracker_id ) ) ) {
/* TODO: log packet coming from ourselves */
continue;
}
switch( uint32_read_big( (char*)g_inbuffer ) ) {
case OT_SYNC_PEER:
livesync_handle_peersync( datalen );
break;
#ifdef WANT_SYNC_SCRAPE
case OT_SYNC_SCRAPE_BEACON:
livesync_handle_beacon( datalen );
break;
case OT_SYNC_SCRAPE_INQUIRE:
livesync_handle_inquire( datalen );
break;
case OT_SYNC_SCRAPE_TELL:
livesync_handle_tell( datalen );
break;
#endif /* WANT_SYNC_SCRAPE */
default:
break;
}
}
/* Never returns. */
return NULL;
}
#endif
const char *g_version_livesync_c = "$Source$: $Revision$\n";