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>
/* Libowfat */
#include "socket.h"
#include "ndelay.h"
/* Opentracker */
#include "trackerlogic.h"
#include "ot_livesync.h"
#include "ot_accesslist.h"
#ifdef WANT_SYNC_LIVE
char groupip_1[4] = { 224,0,23,42 };
#define LIVESYNC_BUFFINSIZE (256*256)
#define LIVESYNC_BUFFSIZE 1504
#define LIVESYNC_BUFFWATER (sizeof(ot_peer)+sizeof(ot_hash))
#define LIVESYNC_MAXDELAY 15
/* Forward declaration */
static void * livesync_worker( void * args );
/* For outgoing packets */
static int64 g_livesync_socket_in = -1;
/* For incoming packets */
static int64 g_livesync_socket_out = -1;
static uint8_t livesync_inbuffer[LIVESYNC_BUFFINSIZE];
static uint8_t livesync_outbuffer_start[ LIVESYNC_BUFFSIZE ];
static uint8_t *livesync_outbuffer_pos;
static uint8_t *livesync_outbuffer_highwater = livesync_outbuffer_start + LIVESYNC_BUFFSIZE - LIVESYNC_BUFFWATER;
static ot_time livesync_lastpacket_time;
static pthread_t thread_id;
void livesync_init( ) {
if( g_livesync_socket_in == -1 )
exerr( "No socket address for live sync specified." );
livesync_outbuffer_pos = livesync_outbuffer_start;
memmove( livesync_outbuffer_pos, &g_tracker_id, sizeof( g_tracker_id ) );
livesync_outbuffer_pos += sizeof( g_tracker_id );
livesync_lastpacket_time = g_now;
pthread_create( &thread_id, NULL, livesync_worker, NULL );
}
void livesync_deinit() {
pthread_cancel( thread_id );
}
void livesync_bind_mcast( char *ip, uint16_t port) {
char tmpip[4] = {0,0,0,0};
if( g_livesync_socket_in != -1 )
exerr("Error: Livesync listen ip specified twice.");
if( ( g_livesync_socket_in = socket_udp4( )) < 0)
exerr("Error: Cant create live sync incoming socket." );
ndelay_off(g_livesync_socket_in);
if( socket_bind4_reuse( g_livesync_socket_in, tmpip, port ) == -1 )
exerr("Error: Cant bind live sync incoming socket." );
if( socket_mcjoin4( g_livesync_socket_in, groupip_1, ip ) )
exerr("Error: Cant make live sync incoming socket join mcast group.");
if( ( g_livesync_socket_out = socket_udp4()) < 0)
exerr("Error: Cant create live sync outgoing socket." );
if( socket_bind4_reuse( g_livesync_socket_out, ip, port ) == -1 )
exerr("Error: Cant bind live sync outgoing socket." );
socket_mcttl4(g_livesync_socket_out, 1);
socket_mcloop4(g_livesync_socket_out, 0);
}
static void livesync_issuepacket( ) {
socket_send4(g_livesync_socket_out, (char*)livesync_outbuffer_start, livesync_outbuffer_pos - livesync_outbuffer_start,
groupip_1, LIVESYNC_PORT);
livesync_outbuffer_pos = livesync_outbuffer_start + sizeof( g_tracker_id );
livesync_lastpacket_time = g_now;
}
/* Inform live sync about whats going on. */
void livesync_tell( ot_hash * const info_hash, const ot_peer * const peer, const uint8_t peerflag ) {
memmove( livesync_outbuffer_pos , info_hash, sizeof(ot_hash));
memmove( livesync_outbuffer_pos + sizeof(ot_hash), peer, sizeof(ot_peer));
OT_FLAG( livesync_outbuffer_pos + sizeof(ot_hash) ) |= peerflag;
livesync_outbuffer_pos += sizeof(ot_hash) + sizeof(ot_peer);
if( livesync_outbuffer_pos >= livesync_outbuffer_highwater )
livesync_issuepacket();
}
/* 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( ) {
if( ( g_now - livesync_lastpacket_time > LIVESYNC_MAXDELAY) &&
( livesync_outbuffer_pos > livesync_outbuffer_start + sizeof( g_tracker_id ) ) )
livesync_issuepacket();
}
static void * livesync_worker( void * args ) {
uint8_t in_ip[4]; uint16_t in_port;
ssize_t datalen;
int off;
args = args;
while( 1 ) {
datalen = socket_recv4(g_livesync_socket_in, (char*)livesync_inbuffer, LIVESYNC_BUFFINSIZE, (char*)in_ip, &in_port);
off = 4;
if( datalen <= 0 )
continue;
if( datalen < (ssize_t)(sizeof( g_tracker_id ) + sizeof( ot_hash ) + sizeof( ot_peer ) ) ) {
// TODO: log invalid sync packet
continue;
}
if( !accesslist_isblessed((char*)in_ip, OT_PERMISSION_MAY_LIVESYNC)) {
// TODO: log invalid sync packet
continue;
}
if( !memcmp( livesync_inbuffer, &g_tracker_id, sizeof( g_tracker_id ) ) ) {
// TODO: log packet coming from ourselves
continue;
}
// 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*)(livesync_inbuffer + off + sizeof(ot_hash));
ot_hash *hash = (ot_hash*)(livesync_inbuffer + off);
if( OT_FLAG(peer) & PEER_FLAG_STOPPED )
remove_peer_from_torrent(hash, peer, NULL, FLAG_MCA);
else
add_peer_to_torrent( hash, peer WANT_SYNC_PARAM(1));
off += sizeof( ot_hash ) + sizeof( ot_peer );
}
}
/* Never returns. */
return NULL;
}
#endif
const char *g_version_livesync_c = "$Source$: $Revision$\n";