ot_livesync.h

   1 /* This software was written by Dirk Engling <erdgeist@erdgeist.org>
   2  It is considered beerware. Prost. Skol. Cheers or whatever.
   3
   4  $id$ */
   5
   6 #ifndef OT_LIVESYNC_H__
   7 #define OT_LIVESYNC_H__
   8
   9 #include "io.h"
  10 #include "trackerlogic.h"
  11
  12 /*
  13   Syncing is done as udp packets in the multicast domain 224.0.42.5 port 9696
  14
  15   Each tracker should join the multicast group and send its live sync packets
  16   to that group, using a ttl of 1
  17
  18   Format of all sync packets is straight forward, packet type determines
  19   which kind of packet this is:
  20
  21     0x0000 0x04 id of tracker instance
  22     0x0004 0x04 packet type
  23
  24                              ########
  25  ######## PEER SYNC PROTOCOL ########
  26  ########
  27
  28   Each tracker instance accumulates announce requests until its buffer is
  29   full or a timeout is reached. Then it broadcasts its live sync packer:
  30
  31   packet type SYNC_LIVE4
  32   [ 0x0008 0x14 info_hash
  33     0x001c 0x04 peer's ipv4 address
  34     0x0020 0x02 peer's port
  35     0x0024 0x02 peer flags v1 ( SEEDING = 0x80, COMPLETE = 0x40, STOPPED = 0x20 )
  36   ]*
  37
  38   packet type SYNC_LIVE6
  39   [ 0x0008 0x14 info_hash
  40     0x001c 0x10 peer's ipv6 address
  41     0x002c 0x02 peer's port
  42     0x002e 0x02 peer flags v1 ( SEEDING = 0x80, COMPLETE = 0x40, STOPPED = 0x20 )
  43   ]*
  44 */
  45
  46 #ifdef WANT_SYNC_LIVE
  47
  48 #define LIVESYNC_PORT 9696
  49
  50 void livesync_init();
  51 void livesync_deinit();
  52
  53 /* Join multicast group for listening and create sending socket */
  54 void livesync_bind_mcast( char *ip, uint16_t port );
  55
  56 /* Inform live sync about whats going on. */
  57 void livesync_tell( struct ot_workstruct *ws );
  58
  59 /* Tickle the live sync module from time to time, so no events get
  60    stuck when there's not enough traffic to fill udp packets fast
  61    enough */
  62 void livesync_ticker( );
  63
  64 /* Handle an incoming live sync packet */
  65 void handle_livesync( const int64 sock );
  66
  67 #else
  68
  69 /* If no syncing is required, save calling code from #ifdef
  70    constructions */
  71 #define livesync_deinit()
  72 #define livesync_init()
  73 #define livesync_ticker()
  74 #define handle_livesync(a)
  75
  76 #endif
  77
  78 #endif