From ad472597c569568bad0526d116b601dfcb36638c Mon Sep 17 00:00:00 2001 From: erdgeist <> Date: Tue, 5 Dec 2006 12:56:56 +0000 Subject: Kickoff --- trackerlogic.c | 273 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 273 insertions(+) create mode 100644 trackerlogic.c (limited to 'trackerlogic.c') diff --git a/trackerlogic.c b/trackerlogic.c new file mode 100644 index 0000000..d21fc01 --- /dev/null +++ b/trackerlogic.c @@ -0,0 +1,273 @@ +// THIS REALLY BELONGS INTO A HEADER FILE +// +// +#include +#include +#include +#include +#include + +typedef unsigned char ot_hash[20]; +typedef unsigned char ot_ip[ 4/*0*/ ]; +typedef unsigned long ot_time; +// tunables +const unsigned long OT_TIMEOUT = 2700; +const unsigned long OT_HUGE_FILESIZE = 1024*1024*256; // Thats 256MB per file, enough for 204800 peers of 128 bytes + +#define OT_COMPACT_ONLY + +#define MEMMOVE memmove +#define BZERO bzero +#define FORMAT_FIXED_STRING sprintf +#define FORMAT_FORMAT_STRING sprintf +#define BINARY_FIND binary_search + +typedef struct { +#ifndef OT_COMPACT_ONLY + ot_hash id; + ot_hash key; +#endif + ot_ip ip; + unsigned short port; + ot_time death; + unsigned char flags; +} ot_peer; +unsigned char PEER_FLAG_SEEDING = 0x80; +unsigned char PEER_IP_LENGTH_MASK = 0x3f; + +typedef struct { + ot_hash hash; + ot_peer *peer_list; + unsigned long peer_count; + unsigned long seed_count; +} ot_torrent; + +void *map_file( char *file_name ); + +// This behaves quite like bsearch but allows to find +// the insertion point for inserts after unsuccessful searches +// in this case exactmatch is 0 on exit +// +void *binary_search( const void *key, const void *base, + const unsigned long member_count, const unsigned long member_size, + int (*compar) (const void *, const void *), + int *exactmatch ); + +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 ) { return memcmp( peer1, peer2, 6); } + +// +// +// END OF STUFF THAT BELONGS INTO A HEADER FILE + +ot_torrent *torrents_pointer = 0; +unsigned long torrents_count = 0; +unsigned char *scratchspace; + +ot_torrent *add_peer_to_torrent( ot_hash hash, ot_peer *peer ) { + ot_torrent *torrent; + ot_peer *peer_dest; + int exactmatch; + + torrent = BINARY_FIND( hash, torrents_pointer, torrents_count, sizeof( ot_torrent ), compare_hash, &exactmatch ); + if( !exactmatch ) { + // Assume, OS will provide us with space, after all, this is file backed + MEMMOVE( torrent + 1, torrent, ( torrents_pointer + torrents_count ) - torrent ); + + // Create a new torrent entry, then + MEMMOVE( &torrent->hash, hash, sizeof( ot_hash ) ); + torrent->peer_list = map_file( hash ); + torrent->peer_count = 0; + torrent->seed_count = 0; + } + + peer_dest = BINARY_FIND( peer, torrent->peer_list, torrent->peer_count, sizeof( ot_peer ), compare_ip_port, &exactmatch ); + if( exactmatch ) { + // If peer was a seeder but isn't anymore, decrease seeder count + if( ( peer_dest->flags & PEER_FLAG_SEEDING ) && !( peer->flags & PEER_FLAG_SEEDING ) ) + torrent->seed_count--; + if( !( peer_dest->flags & PEER_FLAG_SEEDING ) && ( peer->flags & PEER_FLAG_SEEDING ) ) + torrent->seed_count++; + } else { + // Assume, OS will provide us with space, after all, this is file backed + MEMMOVE( peer_dest + 1, peer_dest, ( torrent->peer_list + torrent->peer_count ) - peer_dest ); + + // Create a new peer entry, then + MEMMOVE( peer_dest, peer, sizeof( ot_peer ) ); + + torrent->peer_count++; + torrent->seed_count+= ( peer->flags & PEER_FLAG_SEEDING ) ? 1 : 0; + } + + // Set new time out time + peer_dest->death = now() + OT_TIMEOUT; + + return torrent; +} + +#define SETINVALID( i ) (scratchspace[index] = 3); +#define SETSELECTED( i ) (scratchspace[index] = 1); +#define TESTSELECTED( i ) (scratchspace[index] == 1 ) +#define TESTSET( i ) (scratchspace[index]) +#define RANDOM random() + +inline int TESTVALIDPEER( ot_peer *p ) { return p->death > now(); } + +// Compiles a list of random peers for a torrent +// * scratch space keeps track of death or already selected peers +// * reply must have enough space to hold 1+(1+16+2+1)*amount+1 bytes +// * Selector function can be anything, maybe test for seeds, etc. +// * that RANDOM may return huge values +// * does not yet check not to return self +// * it is not guaranteed to see all peers, so no assumptions on active seeders/peers may be done +// * since compact format cannot handle v6 addresses, it must be enabled by OT_COMPACT_ONLY +// +void return_peers_for_torrent( ot_torrent *torrent, unsigned long amount, char *reply ) { + register ot_peer *peer_base = torrent->peer_list; + unsigned long peer_count = torrent->peer_count; + unsigned long selected_count = 0, invalid_count = 0; + unsigned long index = 0; + + // optimize later ;) + BZERO( scratchspace, peer_count ); + + while( ( selected_count < amount ) && ( selected_count + invalid_count < peer_count ) ) { + // skip to first non-flagged peer + while( TESTSET(index) ) index = ( index + 1 ) % peer_count; + + if( TESTVALIDPEER( peer_base + index ) ) { + SETINVALID(index); invalid_count++; + } else { + SETSELECTED(index); selected_count++; + index = ( index + RANDOM ) % peer_count; + } + } + + // Now our scratchspace contains a list of selected_count valid peers + // Collect them into a reply string + index = 0; + +#ifndef OT_COMPACT_ONLY + reply += FORMAT_FIXED_STRING( reply, "d5:peersl" ); +#else + reply += FORMAT_FORMAT_STRING( reply, "d5:peers%i:",6*selected_count ); +#endif + + while( selected_count-- ) { + ot_peer *peer; + while( !TESTSELECTED( index ) ) ++index; + peer = peer_base + index; +#ifdef OT_COMPACT_ONLY + MEMMOVE( reply, &peer->ip, 4 ); + MEMMOVE( reply+4, &peer->port, 2 ); + reply += 6; +#else + reply += FORMAT_FORMAT_STRING( reply, "d2:ip%d:%s7:peer id20:%20c4:porti%ie", + peer->flags & PEER_IP_LENGTH_MASK, + peer->ip, + peer->id, + peer->port ); +#endif + } +#ifndef OT_COMPACT_ONLY + reply += FORMAT_FIXED_STRING( reply, "ee" ); +#else + reply += FORMAT_FIXED_STRING( reply, "e" ); +#endif +} + +// Compacts a torrents peer list +// * torrents older than OT_TIMEOUT are being kicked +// * is rather expansive +// * if this fails, torrent file is invalid, should add flag +// +void heal_torrent( ot_torrent *torrent ) { + unsigned long index = 0, base = 0, end, seed_count = 0; + + // Initialize base to first dead peer. + while( ( base < torrent->peer_count ) && torrent->peer_list[base].death <= now() ) { + seed_count += ( torrent->peer_list[base].flags & PEER_FLAG_SEEDING ) ? 1 : 0; + base++; + } + + // No dead peers? Home. + if( base == torrent->peer_count ) return; + + // From now index always looks to the next living peer while base keeps track of + // the dead peer that marks the beginning of insert space. + index = base + 1; + + while( 1 ) { + // Let index search for next living peer + while( ( index < torrent->peer_count ) && torrent->peer_list[index].death > now() ) index++; + + // No further living peers found - base is our new peer count + if( index == torrent->peer_count ) { + torrent->peer_count = base; + torrent->seed_count = seed_count; + return; + } + + end = index + 1; + + // Let end search for next dead peer (end of living peers) + while( ( end < torrent->peer_count ) && torrent->peer_list[end].death <= now() ) { + seed_count += ( torrent->peer_list[end].flags & PEER_FLAG_SEEDING ) ? 1 : 0; + end++; + } + + // We either hit a dead peer or the end of our peers + // In both cases: move block towards base + MEMMOVE( torrent->peer_list + base, torrent->peer_list + index, ( end - index ) * sizeof( ot_peer ) ); + base += end - index; + + index = end; + } +} + +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 ) { + unsigned char *lookat = ((unsigned char*)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 = ((unsigned char*)base) + member_size * (member_count >> 1); + } + *exactmatch = 0; + return (void*)lookat; + +} + +// This function maps a "huge" file into process space +// * I guess, we should be checking for more errors... +void *map_file( char *file_name ) { + char *map; + int file_desc=open(file_name,O_RDWR|O_CREAT|O_NDELAY,0644); + + if( file_desc < 0) return 0; + + map=mmap(0,OT_HUGE_FILESIZE,PROT_READ|PROT_WRITE,MAP_SHARED,file_desc,0); + close(file_desc); + + return (map == (char*)-1) ? 0 : map; +} + +int init_logic( ) { + unlink( "./opentracker_map_index.idx" ); + torrents_pointer = map_file( "./opentracker_map_index.idx" ); + torrents_count = 0; + scratchspace = map_file( "./scratchspace" ); +} + +void deinit_logic( ) { + unmap_file( torrents_pointer ); +} -- cgit v1.2.3