Live syncing between multiple tracker instances via udp multicast.

1 files changed, 85 insertions, 0 deletions

diff --git a/ot_livesync.h b/ot_livesync.h
new file mode 100644
index 0000000..4dc6b60
--- /dev/null
+++ b/ot_livesync.h
@@ -0,0 +1,85 @@
+/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
+ It is considered beerware. Prost. Skol. Cheers or whatever.
+ 
+ $id$ */
+
+#ifndef __OT_LIVESYNC_H__
+#define __OT_LIVESYNC_H__
+
+#include "io.h"
+#include "trackerlogic.h"
+
+/*
+  Syncing is done as udp packets in the multicast domain 224.23.42.N port 9696
+
+  Each tracker should join the multicast group and send its live sync packets
+  to that group, using a ttl of 1
+
+  Format of a live sync packet is straight forward and depends on N:
+
+  For N == 1: (simple tracker2tracker sync)
+    0x0000 0x04 id of tracker instance
+  [ 0x0004 0x14 info_hash
+    0x0018 0x04 peer's ipv4 address
+    0x001c 0x02 peer's port
+    0x0020 0x02 peer flags v1 ( SEEDING = 0x80, COMPLETE = 0x40, STOPPED = 0x20 )
+  ]*
+ 
+  For N == 2: (aggregator syncs)
+    0x0000 0x04 id of tracker instance
+  [ 0x0004 0x14 info_hash
+    0x0018 0x01 number of peers
+    [ 0x0019 0x04 peer's ipv4 address
+      0x001a 0x02 peer's port
+      0x0021 0x02 peer flags v1 ( SEEDING = 0x80, COMPLETE = 0x40, STOPPED = 0x20 )
+    ]+
+  ]*
+ 
+
+ */
+
+#ifdef WANT_SYNC_LIVE
+
+#define LIVESYNC_PORT 9696
+#define LIVESYNC_MCASTDOMAIN_1 224,23,42,1
+#define LIVESYNC_MCASTDOMAIN_2 224,23,42,2
+extern char groupip_1[4];
+extern char groupip_2[4];
+
+extern int64 g_livesync_socket;
+
+#define LIVESYNC_BUFFINSIZE (256*256)
+#define LIVESYNC_BUFFSIZE  1504
+#define LIVESYNC_BUFFWATER (sizeof(ot_peer)+sizeof(ot_hash))
+
+#define LIVESYNC_MAXDELAY  15
+
+void livesync_init();
+void livesync_deinit();
+
+/* Join multicast group for listening and create sending socket */
+void livesync_bind_mcast( char *ip, uint16_t port );
+
+/* Inform live sync about whats going on. */
+void livesync_tell( ot_hash * const info_hash, const ot_peer * const peer, const uint8_t peerflag );
+
+/* Tickle the live sync module from time to time, so no events get
+   stuck when there's not enough traffic to fill udp packets fast
+   enough */
+void livesync_ticker( );
+
+/* Handle an incoming live sync packet */
+void handle_livesync( const int64 serversocket );
+
+#else
+
+/* If no syncing is required, save calling code from #ifdef 
+   constructions */
+
+#define livesync_init()
+#define livesync_ticker()
+#define handle_livesync(a)
+
+#endif
+
+#endif