From 00c8a89efe6757ee0cbe43f776f4f7985d988291 Mon Sep 17 00:00:00 2001 From: erdgeist <> Date: Fri, 3 Oct 2008 21:33:53 +0000 Subject: Live syncing between multiple tracker instances via udp multicast. --- ot_livesync.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ot_livesync.h | 85 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 207 insertions(+) create mode 100644 ot_livesync.c create mode 100644 ot_livesync.h diff --git a/ot_livesync.c b/ot_livesync.c new file mode 100644 index 0000000..577bb5f --- /dev/null +++ b/ot_livesync.c @@ -0,0 +1,122 @@ +/* This software was written by Dirk Engling + It is considered beerware. Prost. Skol. Cheers or whatever. + + $id$ */ + +/* System */ +#include +#include +#include + +/* Libowfat */ +#include "socket.h" + +/* Opentracker */ +#include "trackerlogic.h" +#include "ot_livesync.h" +#include "ot_accesslist.h" + +#ifdef WANT_SYNC_LIVE +char groupip_1[4] = { LIVESYNC_MCASTDOMAIN_1 }; + +/* For outgoing packets */ +int64 g_livesync_socket = -1; + +static uint8_t livesync_inbuffer[LIVESYNC_BUFFINSIZE]; +static uint8_t livesync_outbuffer_start[ LIVESYNC_BUFFSIZE ]; +static uint8_t *livesync_outbuffer_pos; +static uint8_t *livesync_outbuffer_highwater = livesync_outbuffer_start + LIVESYNC_BUFFSIZE - LIVESYNC_BUFFWATER; +static ot_time livesync_lastpacket_time; + +void livesync_init( ) { + if( g_livesync_socket == -1 ) + exerr( "No socket address for live sync specified." ); + livesync_outbuffer_pos = livesync_outbuffer_start; + memmove( livesync_outbuffer_pos, &g_tracker_id, sizeof( g_tracker_id ) ); + livesync_outbuffer_pos += sizeof( g_tracker_id ); + livesync_lastpacket_time = g_now; +} + +void livesync_deinit() { + +} + +void livesync_bind_mcast( char *ip, uint16_t port) { + char tmpip[4] = {0,0,0,0}; + if( g_livesync_socket != -1 ) + exerr("Livesync listen ip specified twice."); + if( socket_mcjoin4( ot_try_bind(tmpip, port, FLAG_MCA ), groupip_1, ip ) ) + exerr("Cant join mcast group."); + g_livesync_socket = ot_try_bind( ip, port, FLAG_UDP ); + io_dontwantread(g_livesync_socket); + + socket_mcttl4(g_livesync_socket, 1); + socket_mcloop4(g_livesync_socket, 0); +} + +static void livesync_issuepacket( ) { + socket_send4(g_livesync_socket, (char*)livesync_outbuffer_start, livesync_outbuffer_pos - livesync_outbuffer_start, + groupip_1, LIVESYNC_PORT); + livesync_outbuffer_pos = livesync_outbuffer_start + sizeof( g_tracker_id ); + livesync_lastpacket_time = g_now; +} + +/* Inform live sync about whats going on. */ +void livesync_tell( ot_hash * const info_hash, const ot_peer * const peer, const uint8_t peerflag ) { + memmove( livesync_outbuffer_pos , info_hash, sizeof(ot_hash)); + memmove( livesync_outbuffer_pos + sizeof(ot_hash), peer, sizeof(ot_peer)); + OT_FLAG( livesync_outbuffer_pos + sizeof(ot_hash) ) |= peerflag; + + livesync_outbuffer_pos += sizeof(ot_hash) + sizeof(ot_peer); + if( livesync_outbuffer_pos >= livesync_outbuffer_highwater ) + livesync_issuepacket(); +} + +/* 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( ) { + if( ( g_now - livesync_lastpacket_time > LIVESYNC_MAXDELAY) && + ( livesync_outbuffer_pos > livesync_outbuffer_start + sizeof( g_tracker_id ) ) ) + livesync_issuepacket(); +} + +/* Handle an incoming live sync packet */ +void handle_livesync( int64 serversocket ) { + uint8_t in_ip[4]; uint16_t in_port; + ssize_t datalen = socket_recv4(serversocket, (char*)livesync_inbuffer, LIVESYNC_BUFFINSIZE, (char*)in_ip, &in_port); + int off = 4; + + if( datalen < (ssize_t)(sizeof( g_tracker_id ) + sizeof( ot_hash ) + sizeof( ot_peer ) ) ) { + // TODO: log invalid sync packet + return; + } + + if( !accesslist_isblessed((char*)in_ip, OT_PERMISSION_MAY_LIVESYNC)) { + // TODO: log invalid sync packet + return; + } + + if( !memcmp( livesync_inbuffer, &g_tracker_id, sizeof( g_tracker_id ) ) ) { + // TODO: log packet coming from ourselves + return; + } + + // Now basic sanity checks have been done on the live sync packet + // We might add more testing and logging. + while( off + (ssize_t)sizeof( ot_hash ) + (ssize_t)sizeof( ot_peer ) <= datalen ) { + ot_peer *peer = (ot_peer*)(livesync_inbuffer + off + sizeof(ot_hash)); + ot_hash *hash = (ot_hash*)(livesync_inbuffer + off); + + if( OT_FLAG(peer) & PEER_FLAG_STOPPED ) + remove_peer_from_torrent(hash, peer, NULL, FLAG_MCA); + else + add_peer_to_torrent( hash, peer WANT_SYNC_PARAM(1)); + + off += sizeof( ot_hash ) + sizeof( ot_peer ); + } + +} + +#endif +const char *g_version_livesync_c = "$Source$: $Revision$\n"; 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 + 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 -- cgit v1.2.3