/* UDP implementation according to http://xbtt.sourceforge.net/udp_tracker_protocol.html */
int handle_udp6( int64 serversocket, struct ot_workstruct *ws ) {
ot_ip6 remoteip;
uint32_t *inpacket = (uint32_t*)ws->inbuf;
uint32_t *outpacket = (uint32_t*)ws->outbuf;
uint32_t numwant, left, event, scopeid;
uint32_t connid[2];
uint16_t port, remoteport;
size_t byte_count, scrape_count;
byte_count = socket_recv6( serversocket, ws->inbuf, G_INBUF_SIZE, remoteip, &remoteport, &scopeid );
if( !byte_count ) return 0;
stats_issue_event( EVENT_ACCEPT, FLAG_UDP, (uintptr_t)remoteip );
stats_issue_event( EVENT_READ, FLAG_UDP, byte_count );
/* Minimum udp tracker packet size, also catches error */
if( byte_count < 16 )
return 1;
/* Generate the connection id we give out and expect to and from
the requesting ip address, this prevents udp spoofing */
udp_make_connectionid( connid, remoteip, 0 );
/* Initialise hash pointer */
ws->hash = NULL;
ws->peer_id = NULL;
/* If action is not a ntohl(a) == a == 0, then we
expect the derived connection id in first 64 bit */
if( inpacket[2] && ( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) ) {
/* If connection id does not match, try the one that was
valid in the previous hour. Only if this also does not
match, return an error packet */
udp_make_connectionid( connid, remoteip, 1 );
if( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) {
const size_t s = sizeof( "Connection ID missmatch." );
outpacket[0] = 3; outpacket[1] = inpacket[3];
memcpy( &outpacket[2], "Connection ID missmatch.", s );
socket_send6( serversocket, ws->outbuf, 8 + s, remoteip, remoteport, 0 );
stats_issue_event( EVENT_CONNID_MISSMATCH, FLAG_UDP, 8 + s );
return 1;
}
}
switch( ntohl( inpacket[2] ) ) {
case 0: /* This is a connect action */
/* look for udp bittorrent magic id */
if( (ntohl(inpacket[0]) != 0x00000417) || (ntohl(inpacket[1]) != 0x27101980) )
return 1;
outpacket[0] = 0;
outpacket[1] = inpacket[3];
outpacket[2] = connid[0];
outpacket[3] = connid[1];
socket_send6( serversocket, ws->outbuf, 16, remoteip, remoteport, 0 );
stats_issue_event( EVENT_CONNECT, FLAG_UDP, 16 );
break;
case 1: /* This is an announce action */
/* Minimum udp announce packet size */
if( byte_count < 98 )
return 1;
/* We do only want to know, if it is zero */
left = inpacket[64/4] | inpacket[68/4];
numwant = ntohl( inpacket[92/4] );
if (numwant > 200) numwant = 200;
event = ntohl( inpacket[80/4] );
port = *(uint16_t*)( ((char*)inpacket) + 96 );
ws->hash = (ot_hash*)( ((char*)inpacket) + 16 );
OT_SETIP( &ws->peer, remoteip );
OT_SETPORT( &ws->peer, &port );
OT_PEERFLAG( &ws->peer ) = 0;
switch( event ) {
case 1: OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_COMPLETED; break;
case 3: OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_STOPPED; break;
default: break;
}
if( !left )
OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_SEEDING;
outpacket[0] = htonl( 1 ); /* announce action */
outpacket[1] = inpacket[12/4];
if( OT_PEERFLAG( &ws->peer ) & PEER_FLAG_STOPPED ) { /* Peer is gone. */
ws->reply = ws->outbuf;
ws->reply_size = remove_peer_from_torrent( FLAG_UDP, ws );
} else {
ws->reply = ws->outbuf + 8;
ws->reply_size = 8 + add_peer_to_torrent_and_return_peers( FLAG_UDP, ws, numwant );
}
socket_send6( serversocket, ws->outbuf, ws->reply_size, remoteip, remoteport, 0 );
stats_issue_event( EVENT_ANNOUNCE, FLAG_UDP, ws->reply_size );
break;
case 2: /* This is a scrape action */
outpacket[0] = htonl( 2 ); /* scrape action */
outpacket[1] = inpacket[12/4];
for( scrape_count = 0; ( scrape_count * 20 < byte_count - 16) && ( scrape_count <= 74 ); scrape_count++ )
return_udp_scrape_for_torrent( *(ot_hash*)( ((char*)inpacket) + 16 + 20 * scrape_count ), ((char*)outpacket) + 8 + 12 * scrape_count );
socket_send6( serversocket, ws->outbuf, 8 + 12 * scrape_count, remoteip, remoteport, 0 );
stats_issue_event( EVENT_SCRAPE, FLAG_UDP, scrape_count );
break;
}
return 1;
}
static ssize_t http_handle_announce( const int64 sock, struct ot_workstruct *ws, char *read_ptr ) {
int numwant, tmp, scanon;
unsigned short port = 0;
char *write_ptr;
ssize_t len;
struct http_data *cookie = io_getcookie( sock );
/* This is to hack around stupid clients that send "announce ?info_hash" */
if( read_ptr[-1] != '?' ) {
while( ( *read_ptr != '?' ) && ( *read_ptr != '\n' ) ) ++read_ptr;
if( *read_ptr == '\n' ) HTTPERROR_400_PARAM;
++read_ptr;
}
#ifdef WANT_IP_FROM_PROXY
if( accesslist_isblessed( cookie->ip, OT_PERMISSION_MAY_PROXY ) ) {
ot_ip6 proxied_ip;
char *fwd = http_header( ws->request, ws->header_size, "x-forwarded-for" );
if( fwd && scan_ip6( fwd, proxied_ip ) )
OT_SETIP( &ws->peer, proxied_ip );
else
OT_SETIP( &ws->peer, cookie->ip );
} else
#endif
OT_SETIP( &ws->peer, cookie->ip );
ws->peer_id = NULL;
ws->hash = NULL;
OT_SETPORT( &ws->peer, &port );
OT_PEERFLAG( &ws->peer ) = 0;
numwant = 50;
scanon = 1;
while( scanon ) {
switch( scan_find_keywords(keywords_announce, &read_ptr, SCAN_SEARCHPATH_PARAM ) ) {
case -2: scanon = 0; break; /* TERMINATOR */
case -1: HTTPERROR_400_PARAM; /* PARSE ERROR */
case -3: scan_urlencoded_skipvalue( &read_ptr ); break;
case 1: /* matched "port" */
len = scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE );
if( ( len <= 0 ) || scan_fixed_int( write_ptr, len, &tmp ) || ( tmp > 0xffff ) ) HTTPERROR_400_PARAM;
port = htons( tmp ); OT_SETPORT( &ws->peer, &port );
break;
case 2: /* matched "left" */
if( ( len = scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE ) ) <= 0 ) HTTPERROR_400_PARAM;
if( scan_fixed_int( write_ptr, len, &tmp ) ) tmp = 0;
if( !tmp ) OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_SEEDING;
break;
case 3: /* matched "event" */
switch( scan_find_keywords( keywords_announce_event, &read_ptr, SCAN_SEARCHPATH_VALUE ) ) {
case -1: HTTPERROR_400_PARAM;
case 1: /* matched "completed" */
OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_COMPLETED;
break;
case 2: /* matched "stopped" */
OT_PEERFLAG( &ws->peer ) |= PEER_FLAG_STOPPED;
break;
default:
break;
}
break;
case 4: /* matched "numwant" */
len = scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE );
if( ( len <= 0 ) || scan_fixed_int( write_ptr, len, &numwant ) ) HTTPERROR_400_PARAM;
if( numwant < 0 ) numwant = 50;
if( numwant > 200 ) numwant = 200;
break;
case 5: /* matched "compact" */
len = scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE );
if( ( len <= 0 ) || scan_fixed_int( write_ptr, len, &tmp ) ) HTTPERROR_400_PARAM;
if( !tmp ) HTTPERROR_400_COMPACT;
break;
case 6: /* matched "info_hash" */
if( ws->hash ) HTTPERROR_400_DOUBLEHASH;
/* ignore this, when we have less than 20 bytes */
if( scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE ) != 20 ) HTTPERROR_400_PARAM;
ws->hash = (ot_hash*)write_ptr;
break;
#ifdef WANT_IP_FROM_QUERY_STRING
case 7: /* matched "ip" */
{
char *tmp_buf1 = ws->reply, *tmp_buf2 = ws->reply+16;
len = scan_urlencoded_query( &read_ptr, tmp_buf2, SCAN_SEARCHPATH_VALUE );
tmp_buf2[len] = 0;
if( ( len <= 0 ) || !scan_ip6( tmp_buf2, tmp_buf1 ) ) HTTPERROR_400_PARAM;
OT_SETIP( &ws->peer, tmp_buf1 );
}
break;
#endif
#ifdef WANT_FULLLOG_NETWORKS
case 8: /* matched "lognet" */
{
//if( accesslist_isblessed( cookie->ip, OT_PERMISSION_MAY_STAT ) ) {
char *tmp_buf = ws->reply;
ot_net net;
signed short parsed, bits;
len = scan_urlencoded_query( &read_ptr, tmp_buf, SCAN_SEARCHPATH_VALUE );
tmp_buf[len] = 0;
if( len <= 0 ) HTTPERROR_400_PARAM;
if( *tmp_buf == '-' ) {
loglist_reset( );
return ws->reply_size = sprintf( ws->reply, "Successfully removed.\n" );
}
parsed = scan_ip6( tmp_buf, net.address );
if( !parsed ) HTTPERROR_400_PARAM;
if( tmp_buf[parsed++] != '/' )
bits = 128;
else {
parsed = scan_short( tmp_buf + parsed, &bits );
if( !parsed ) HTTPERROR_400_PARAM;
if( ip6_isv4mapped( net.address ) )
bits += 96;
}
net.bits = bits;
loglist_add_network( &net );
return ws->reply_size = sprintf( ws->reply, "Successfully added.\n" );
//}
}
#endif
break;
case 9: /* matched "peer_id" */
/* ignore this, when we have less than 20 bytes */
if( scan_urlencoded_query( &read_ptr, write_ptr = read_ptr, SCAN_SEARCHPATH_VALUE ) != 20 ) HTTPERROR_400_PARAM;
ws->peer_id = write_ptr;
break;
}
}
#ifdef WANT_LOG_NUMWANT
numwants[numwant]++;
#endif
/* XXX DEBUG
stats_issue_event( EVENT_ACCEPT, FLAG_TCP, (uintptr_t)ws->reply );
*/
/* Scanned whole query string */
if( !ws->hash )
return ws->reply_size = sprintf( ws->reply, "d14:failure reason80:Your client forgot to send your torrent's info_hash. Please upgrade your client.e" );
if( OT_PEERFLAG( &ws->peer ) & PEER_FLAG_STOPPED )
ws->reply_size = remove_peer_from_torrent( FLAG_TCP, ws );
else
ws->reply_size = add_peer_to_torrent_and_return_peers( FLAG_TCP, ws, numwant );
stats_issue_event( EVENT_ANNOUNCE, FLAG_TCP, ws->reply_size);
return ws->reply_size;
}
