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142 lines
4.4 KiB
C
142 lines
4.4 KiB
C
/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
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It is considered beerware. Prost. Skol. Cheers or whatever.
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$id$ */
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/* System */
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#include <string.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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/* Libowfat */
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#include "socket.h"
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#include "io.h"
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/* Opentracker */
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#include "trackerlogic.h"
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#include "ot_udp.h"
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#include "ot_stats.h"
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static char static_inbuf[8192];
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static char static_outbuf[8192];
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static const uint8_t g_static_connid[8] = { 0x23, 0x42, 0x05, 0x17, 0xde, 0x41, 0x50, 0xff };
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static void udp_make_connectionid( uint32_t * connid, const char * remoteip ) {
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/* Touch unused variable */
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(void)remoteip;
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/* Use a static secret for now */
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memcpy( connid, g_static_connid, 8 );
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}
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static int udp_test_connectionid( const uint32_t * const connid, const char * remoteip ) {
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/* Touch unused variable */
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(void)remoteip;
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/* Test against our static secret */
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return !memcmp( connid, g_static_connid, 8 );
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}
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/* UDP implementation according to http://xbtt.sourceforge.net/udp_tracker_protocol.html */
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void handle_udp4( int64 serversocket ) {
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ot_peer peer;
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ot_torrent *torrent;
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ot_hash *hash = NULL;
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char remoteip[4];
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uint32_t *inpacket = (uint32_t*)static_inbuf;
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uint32_t *outpacket = (uint32_t*)static_outbuf;
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uint32_t numwant, left, event;
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uint16_t port, remoteport;
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size_t r, r_out;
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r = socket_recv4( serversocket, static_inbuf, sizeof( static_inbuf ), remoteip, &remoteport);
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stats_issue_event( EVENT_ACCEPT, FLAG_UDP, ntohl(*(uint32_t*)remoteip) );
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stats_issue_event( EVENT_READ, FLAG_UDP, r );
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/* Minimum udp tracker packet size, also catches error */
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if( r < 16 )
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return;
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/* fprintf( stderr, "UDP Connection id: %16llX\n", *(uint64_t*)inpacket ); */
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switch( ntohl( inpacket[2] ) ) {
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case 0: /* This is a connect action */
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/* look for udp bittorrent magic id */
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if( (ntohl(inpacket[0]) != 0x00000417) || (ntohl(inpacket[1]) != 0x27101980) )
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return;
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outpacket[0] = 0;
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outpacket[1] = inpacket[3];
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udp_make_connectionid( outpacket + 2, remoteip );
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socket_send4( serversocket, static_outbuf, 16, remoteip, remoteport );
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stats_issue_event( EVENT_CONNECT, FLAG_UDP, 16 );
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break;
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case 1: /* This is an announce action */
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/* Minimum udp announce packet size */
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if( r < 98 )
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return;
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if( !udp_test_connectionid( inpacket, remoteip ))
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fprintf( stderr, "UDP connect Connection id missmatch.\n" );
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/* We do only want to know, if it is zero */
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left = inpacket[64/4] | inpacket[68/4];
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numwant = ntohl( inpacket[92/4] );
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if (numwant > 200) numwant = 200;
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event = ntohl( inpacket[80/4] );
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port = *(uint16_t*)( static_inbuf + 96 );
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hash = (ot_hash*)( static_inbuf + 16 );
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OT_SETIP( &peer, remoteip );
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OT_SETPORT( &peer, &port );
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OT_FLAG( &peer ) = 0;
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switch( event ) {
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case 1: OT_FLAG( &peer ) |= PEER_FLAG_COMPLETED; break;
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case 3: OT_FLAG( &peer ) |= PEER_FLAG_STOPPED; break;
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default: break;
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}
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if( !left )
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OT_FLAG( &peer ) |= PEER_FLAG_SEEDING;
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outpacket[0] = htonl( 1 ); /* announce action */
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outpacket[1] = inpacket[12/4];
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if( OT_FLAG( &peer ) & PEER_FLAG_STOPPED ) /* Peer is gone. */
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r = remove_peer_from_torrent( hash, &peer, static_outbuf, FLAG_UDP );
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else {
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torrent = add_peer_to_torrent( hash, &peer WANT_SYNC_PARAM( 0 ) );
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if( !torrent )
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return; /* XXX maybe send error */
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r = 8 + return_peers_for_torrent( hash, numwant, static_outbuf + 8, FLAG_UDP );
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}
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socket_send4( serversocket, static_outbuf, r, remoteip, remoteport );
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stats_issue_event( EVENT_ANNOUNCE, FLAG_UDP, r );
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break;
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case 2: /* This is a scrape action */
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if( !udp_test_connectionid( inpacket, remoteip ))
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fprintf( stderr, "UDP scrape Connection id missmatch.\n" );
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outpacket[0] = htonl( 2 ); /* scrape action */
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outpacket[1] = inpacket[12/4];
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for( r_out = 0; ( r_out * 20 < r - 16) && ( r_out <= 74 ); r_out++ )
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return_udp_scrape_for_torrent( (ot_hash*)( static_inbuf + 16 + 20 * r_out ), static_outbuf + 8 + 12 * r_out );
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socket_send4( serversocket, static_outbuf, 8 + 12 * r_out, remoteip, remoteport );
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stats_issue_event( EVENT_SCRAPE, FLAG_UDP, r );
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break;
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}
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}
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const char *g_version_udp_c = "$Source$: $Revision$\n";
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