summaryrefslogtreecommitdiff
path: root/trackerlogic.c
blob: 5d83abbc7a5117065463cad69941650d9f253cc8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
#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 *end = ((ot_byte*)vector->data) + member_size * vector->size;
  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 ) {
    void *new_data = realloc( vector->data, vector->space ? 2 * vector->space : 1024 );
    if( !new_data ) return NULL;
    vector->data = new_data;
    vector->space = vector->space ? vector->space * 2 : 1024;
  }
  MEMMOVE( match + member_size, match, end - match );
  vector->size++;
  return match;
}

int vector_remove_peer( ot_vector vector, ot_peer peer ) {
  int exactmatch;
  ot_peer end = ((ot_peer)vector->data) + vector->size;
  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, end - 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;
  unsigned long  pool_offset = 0, 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;

    while( pool_offset + off > torrent->peer_list->peers[pool_index].size ) {
      off -= torrent->peer_list->peers[pool_index].size - pool_offset;
      pool_offset = 0; 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));
}