An open and free bittorrent tracker https://erdgeist.org/gitweb/opentracker
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#include "trackerlogic.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <time.h>
#include <math.h>
#include <glob.h>
#include <errno.h>
#include "scan.h"
#include "byte.h"
// Helper functions for binary_find
//
int compare_hash( const void *hash1, const void *hash2 ) { return memcmp( hash1, hash2, sizeof( ot_hash )); }
int compare_ip_port( const void *peer1, const void *peer2 ) {
if( ((ot_peer)peer1)->ip != ((ot_peer)peer2)->ip ) return ((ot_peer)peer1)->ip - ((ot_peer)peer2)->ip;
return ((ot_peer)peer1)->port_flags - ((ot_peer)peer2)->port_flags; }
void *binary_search( const void *key, const void *base,
unsigned long member_count, const unsigned long member_size,
int (*compar) (const void *, const void *),
int *exactmatch ) {
ot_byte *lookat = ((ot_byte*)base) + member_size * (member_count >> 1);
*exactmatch = 1;
while( member_count ) {
int cmp = compar((void*)lookat, key);
if (cmp == 0) return (void *)lookat;
if (cmp < 0) {
base = (void*)(lookat + member_size);
--member_count;
}
member_count >>= 1;
lookat = ((ot_byte*)base) + member_size * (member_count >> 1);
}
*exactmatch = 0;
return (void*)lookat;
}
// Converter function from memory to human readable hex strings
// * definitely not thread safe!!!
//
char ths[1+2*20];char*to_hex(ot_byte*s){char*m="0123456789ABCDEF";char*e=ths+40;char*t=ths;while(t<e){*t++=m[*s>>4];*t++=m[*s++&15];}*t=0;return ths;}
// GLOBAL VARIABLES
//
struct ot_vector all_torrents[256];
void *vector_find_or_insert( ot_vector vector, void *key, size_t member_size, int(*compare_func)(const void*, const void*), int *exactmatch ) {
ot_byte *match = BINARY_FIND( key, vector->data, vector->size, member_size, compare_func, exactmatch );
if( *exactmatch ) return match;
if( vector->size + 1 >= vector->space ) {
ot_byte *new_data = realloc( vector->data, vector->space ? 2 * vector->space : 1024 );
if( !new_data ) return NULL;
// Adjust pointer if it moved by realloc
match = match - (ot_byte*)vector->data + new_data;
vector->data = new_data;
vector->space = vector->space ? vector->space * 2 : 1024;
}
MEMMOVE( match + member_size, match, ((ot_byte*)vector->data) + member_size * vector->size - match );
vector->size++;
return match;
}
int vector_remove_peer( ot_vector vector, ot_peer peer ) {
int exactmatch;
ot_peer match;
if( !vector->size ) return 0;
match = BINARY_FIND( peer, vector->data, vector->size, sizeof( struct ot_peer ), compare_ip_port, &exactmatch );
if( !exactmatch ) return 0;
exactmatch = match->port_flags & PEER_FLAG_SEEDING ? 2 : 1;
MEMMOVE( match, match + 1, ((ot_peer)vector->data) + vector->size - match - 1 );
vector->size--;
return exactmatch;
}
void free_peerlist( ot_peerlist peer_list ) {
int i;
for( i=0; i<OT_POOLS_COUNT; ++i )
if( peer_list->peers[i].data )
free( peer_list->peers[i].data );
free( peer_list );
}
int vector_remove_torrent( ot_vector vector, ot_hash *hash ) {
int exactmatch;
ot_torrent end = ((ot_torrent)vector->data) + vector->size;
ot_torrent match = BINARY_FIND( hash, vector->data, vector->size, sizeof( struct ot_torrent ), compare_hash, &exactmatch );
if( !exactmatch ) return -1;
free_peerlist( match->peer_list );
MEMMOVE( match, match + 1, end - match - 1 );
vector->size--;
if( ( 3*vector->size < vector->space ) && ( vector->space > 1024 ) ) {
realloc( vector->data, vector->space >> 1 );
vector->space >>= 1;
}
return 0;
}
void clean_peerlist( ot_peerlist peer_list ) {
long timedout = NOW-peer_list->base;
int i;
if( !timedout ) return;
if( timedout > OT_POOLS_COUNT ) timedout = OT_POOLS_COUNT;
for( i=OT_POOLS_COUNT-timedout; i<OT_POOLS_COUNT; ++i )
free( peer_list->peers[i].data);
MEMMOVE( peer_list->peers + timedout, peer_list->peers, sizeof( ot_vector ) * (OT_POOLS_COUNT-timedout) );
byte_zero( peer_list->peers, sizeof( ot_vector ) * timedout );
MEMMOVE( peer_list->seed_count + timedout, peer_list->seed_count, sizeof( unsigned long ) * (OT_POOLS_COUNT-timedout) );
byte_zero( peer_list->seed_count, sizeof( unsigned long ) * timedout );
peer_list->base = NOW;
}
ot_torrent add_peer_to_torrent( ot_hash *hash, ot_peer peer ) {
int exactmatch;
ot_torrent torrent;
ot_peer peer_dest;
ot_vector torrents_list = all_torrents + *hash[0], peer_pool;
torrent = vector_find_or_insert( torrents_list, (void*)hash, sizeof( struct ot_torrent ), compare_hash, &exactmatch );
if( !torrent ) return NULL;
if( !exactmatch ) {
// Create a new torrent entry, then
torrent->peer_list = malloc( sizeof (struct ot_peerlist) );
if( !torrent->peer_list ) {
vector_remove_torrent( torrents_list, hash );
return NULL;
}
MEMMOVE( &torrent->hash, hash, sizeof( ot_hash ) );
byte_zero( torrent->peer_list, sizeof( struct ot_peerlist ));
torrent->peer_list->base = NOW;
} else
clean_peerlist( torrent->peer_list );
peer_pool = &torrent->peer_list->peers[0];
peer_dest = vector_find_or_insert( peer_pool, (void*)peer, sizeof( struct ot_peer ), compare_ip_port, &exactmatch );
// If we hadn't had a match in current pool, create peer there and
// remove it from all older pools
if( !exactmatch ) {
int i;
MEMMOVE( peer_dest, peer, sizeof( struct ot_peer ) );
if( peer->port_flags & PEER_FLAG_SEEDING )
torrent->peer_list->seed_count[0]++;
for( i=1; i<OT_POOLS_COUNT; ++i ) {
switch( vector_remove_peer( &torrent->peer_list->peers[i], peer ) ) {
case 0: continue;
case 2: torrent->peer_list->seed_count[i]--;
case 1: default: return torrent;
}
}
} else {
if( (peer_dest->port_flags & PEER_FLAG_SEEDING ) && !(peer->port_flags & PEER_FLAG_SEEDING ) )
torrent->peer_list->seed_count[0]--;
if( !(peer_dest->port_flags & PEER_FLAG_SEEDING ) && (peer->port_flags & PEER_FLAG_SEEDING ) )
torrent->peer_list->seed_count[0]++;
}
return torrent;
}
// Compiles a list of random peers for a torrent
// * reply must have enough space to hold 24+6*amount bytes
// * Selector function can be anything, maybe test for seeds, etc.
// * RANDOM may return huge values
// * does not yet check not to return self
//
size_t return_peers_for_torrent( ot_torrent torrent, unsigned long amount, char *reply ) {
char *r = reply;
unsigned long peer_count, index;
signed long pool_offset = -1, pool_index = 0;
signed long wert = -1;
for( peer_count=index=0; index<OT_POOLS_COUNT; ++index) peer_count += torrent->peer_list->peers[index].size;
if( peer_count < amount ) amount = peer_count;
r += FORMAT_FORMAT_STRING( r, "d5:peers%li:",6*amount );
for( index = 0; index < amount; ++index ) {
double step = 1.8*((double)( peer_count - wert - 1 ))/((double)( amount - index ));
int off = random() % (int)floor( step );
off = 1 + ( off % ( peer_count - wert - 1 ));
wert += off; pool_offset += off;
while( pool_offset >= torrent->peer_list->peers[pool_index].size ) {
pool_offset -= torrent->peer_list->peers[pool_index].size;
pool_index++;
}
MEMMOVE( r, ((ot_peer*)torrent->peer_list->peers[pool_index].data) + pool_offset, 6 );
r += 6;
}
*r++ = 'e';
return r - reply;
}
int init_logic( char *directory ) {
glob_t globber;
int i;
if( directory ) {
if( chdir( directory ))
return -1;
}
srandom( time(NULL));
// Initialize control structures
byte_zero( all_torrents, sizeof (all_torrents));
// Scan directory for filenames in the form [0-9A-F]{20}
// * I know this looks ugly, but I've seen A-F to match umlauts as well in strange locales
// * lower case for .. better being safe than sorry, this is not expensive here :)
if( !glob(
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
"[0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef][0-9ABCDEFabcdef]"
, GLOB_NOCHECK, 0, &globber) )
{
for( i=0; i<globber.gl_matchc; ++i )
printf( "Found: %s\n", globber.gl_pathv[i] );
}
globfree( &globber );
return 0;
}
void deinit_logic( ) {
int i, j;
// Free all torrents...
for(i=0; i<256; ++i ) {
if( all_torrents[i].size ) {
ot_torrent torrents_list = (ot_torrent)all_torrents[i].data;
for( j=0; j<all_torrents[i].size; ++j )
free_peerlist( torrents_list[j].peer_list );
free( all_torrents[i].data );
}
}
byte_zero( all_torrents, sizeof (all_torrents));
}