modules/control/netsync.c

   1 /*****************************************************************************
   2  * netsync.c: synchronisation between several network clients.
   3  *****************************************************************************
   4  * Copyright (C) 2004 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_interface.h>
  34 #include <vlc_input.h>
  35 #include <vlc_es_out.h>
  36
  37 #ifdef HAVE_UNISTD_H
  38 #    include <unistd.h>
  39 #endif
  40 #ifdef HAVE_SYS_TIME_H
  41 #    include <sys/time.h>
  42 #endif
  43 #ifdef HAVE_SYS_TYPES_H
  44 #   include <sys/types.h>
  45 #endif
  46 #ifdef HAVE_POLL
  47 #   include <poll.h>
  48 #endif
  49
  50 #include <vlc_network.h>
  51
  52 #define NETSYNC_PORT 9875
  53
  54 /* FIXME: UGLY UGLY !! Netsync should be totally reworked */
  55 #include "../../src/input/input_internal.h"
  56
  57 /*****************************************************************************
  58  * Module descriptor
  59  *****************************************************************************/
  60 static int  Activate( vlc_object_t * );
  61 static void Close   ( vlc_object_t * );
  62
  63 static mtime_t GetClockRef( intf_thread_t *, mtime_t );
  64
  65 /// \bug [String] This string is BAD.
  66 #define NETSYNC_TEXT N_( "Act as master" )
  67 #define NETSYNC_LONGTEXT N_( "Should " \
  68   "act as the master client for the network synchronisation?" )
  69
  70 /// \bug [String] This string is BAD.
  71 #define MIP_TEXT N_( "Master client ip address" )
  72 #define MIP_LONGTEXT N_( "IP address of " \
  73   "the master client used for the network synchronisation." )
  74
  75 vlc_module_begin ()
  76     set_shortname( N_("Network Sync"))
  77     set_description( N_("Network synchronisation") )
  78     set_category( CAT_ADVANCED )
  79     set_subcategory( SUBCAT_ADVANCED_MISC )
  80
  81     add_bool( "netsync-master", false, NULL,
  82               NETSYNC_TEXT, NETSYNC_LONGTEXT, true )
  83     add_string( "netsync-master-ip", NULL, NULL, MIP_TEXT, MIP_LONGTEXT,
  84                 true )
  85
  86     set_capability( "interface", 0 )
  87     set_callbacks( Activate, Close )
  88 vlc_module_end ()
  89
  90 /*****************************************************************************
  91  * Local prototypes
  92  *****************************************************************************/
  93 static void Run( intf_thread_t *p_intf );
  94
  95 /*****************************************************************************
  96  * Activate: initialize and create stuff
  97  *****************************************************************************/
  98 static int Activate( vlc_object_t *p_this )
  99 {
 100     intf_thread_t *p_intf = (intf_thread_t*)p_this;
 101     int fd;
 102
 103     if( config_GetInt( p_intf, "netsync-master" ) <= 0 )
 104     {
 105         char *psz_master = config_GetPsz( p_intf, "netsync-master-ip" );
 106         if( psz_master == NULL )
 107         {
 108             msg_Err( p_intf, "master address not specified" );
 109             return VLC_EGENERIC;
 110         }
 111         fd = net_ConnectUDP( VLC_OBJECT(p_intf), psz_master, NETSYNC_PORT, -1 );
 112         free( psz_master );
 113     }
 114     else
 115         fd = net_ListenUDP1( VLC_OBJECT(p_intf), NULL, NETSYNC_PORT );
 116
 117     if( fd == -1 )
 118     {
 119         msg_Err( p_intf, "Netsync socket failure" );
 120         return VLC_EGENERIC;
 121     }
 122
 123     p_intf->p_sys = (void *)(intptr_t)fd;
 124     p_intf->pf_run = Run;
 125     return VLC_SUCCESS;
 126 }
 127
 128 /*****************************************************************************
 129  * Close: destroy interface
 130  *****************************************************************************/
 131 void Close( vlc_object_t *p_this )
 132 {
 133     intf_thread_t *p_intf = (intf_thread_t*)p_this;
 134
 135     net_Close( (intptr_t)p_intf->p_sys );
 136 }
 137
 138 /*****************************************************************************
 139  * Run: interface thread
 140  *****************************************************************************/
 141 static void Run( intf_thread_t *p_intf )
 142 {
 143 #define MAX_MSG_LENGTH (2 * sizeof(int64_t))
 144
 145     input_thread_t *p_input = NULL;
 146     char p_data[MAX_MSG_LENGTH];
 147     int i_socket;
 148     int canc = vlc_savecancel();
 149
 150     /* High priority thread */
 151     vlc_thread_set_priority( p_intf, VLC_THREAD_PRIORITY_INPUT );
 152
 153     while( vlc_object_alive( p_intf ) )
 154     {
 155         /* Update the input */
 156         if( p_input == NULL )
 157             p_input =
 158                 (input_thread_t *)vlc_object_find( p_intf, VLC_OBJECT_INPUT,
 159                                                    FIND_ANYWHERE );
 160         else if( p_input->b_dead )
 161         {
 162             vlc_object_release( p_input );
 163             p_input = NULL;
 164         }
 165
 166         if( p_input == NULL )
 167         {
 168             /* Wait a bit */
 169             msleep( INTF_IDLE_SLEEP );
 170             continue;
 171         }
 172
 173         /*
 174          * We now have an input
 175          */
 176
 177         /* Initialize file descriptor set and timeout (0.5s) */
 178         /* FIXME: arbitrary tick */
 179         struct pollfd ufd = { .fd = i_socket, .events = POLLIN, };
 180
 181         if( b_master )
 182         {
 183             struct sockaddr_storage from;
 184             mtime_t i_date, i_clockref, i_master_clockref;
 185             int i_struct_size, i_read, i_ret;
 186
 187             /* Don't block */
 188             i_ret = poll( &ufd, 1, 500 );
 189             if( i_ret == 0 ) continue;
 190             if( i_ret < 0 )
 191             {
 192                 /* Wait a bit */
 193                 msleep( INTF_IDLE_SLEEP );
 194                 continue;
 195             }
 196
 197             /* We received something */
 198             i_struct_size = sizeof( from );
 199             i_read = recvfrom( i_socket, p_data, MAX_MSG_LENGTH, 0,
 200                                (struct sockaddr*)&from,
 201                                (unsigned int *)&i_struct_size );
 202
 203             i_clockref = ntoh64(*(int64_t *)p_data);
 204
 205             i_date = mdate();
 206             *(int64_t *)p_data = hton64( i_date );
 207
 208             i_master_clockref = GetClockRef( p_intf, i_clockref );
 209             *(((int64_t *)p_data)+1) = hton64( i_master_clockref );
 210
 211             /* Reply to the sender */
 212             sendto( i_socket, p_data, 2 * sizeof(int64_t), 0,
 213                     (struct sockaddr *)&from, i_struct_size );
 214
 215 #if 0
 216             msg_Dbg( p_intf, "Master clockref: %"PRId64" -> %"PRId64", from %s "
 217                      "(date: %"PRId64")", i_clockref, i_master_clockref,
 218                      from.ss_family == AF_INET
 219                      ? inet_ntoa(((struct sockaddr_in *)&from)->sin_addr)
 220                      : "non-IPv4", i_date );
 221 #endif
 222         }
 223         else
 224         {
 225             mtime_t i_send_date, i_receive_date, i_master_date, i_diff_date;
 226             mtime_t i_master_clockref, i_client_clockref, i_drift;
 227             mtime_t i_clockref = 0;
 228             int i_sent, i_read, i_ret;
 229
 230             /* Send clock request to the master */
 231             *(int64_t *)p_data = hton64( i_clockref );
 232             i_send_date = mdate();
 233
 234             i_sent = send( i_socket, p_data, sizeof(int64_t), 0 );
 235             if( i_sent <= 0 )
 236             {
 237                 /* Wait a bit */
 238                 msleep( INTF_IDLE_SLEEP );
 239                 continue;
 240             }
 241
 242             /* Don't block */
 243             i_ret = poll( &ufd, 1, 500 );
 244             if( i_ret == 0 ) continue;
 245             if( i_ret < 0 )
 246             {
 247                 /* Wait a bit */
 248                 msleep( INTF_IDLE_SLEEP );
 249                 continue;
 250             }
 251
 252             i_receive_date = mdate();
 253
 254             i_read = recv( i_socket, p_data, MAX_MSG_LENGTH, 0 );
 255             if( i_read <= 0 )
 256             {
 257                 /* Wait a bit */
 258                 msleep( INTF_IDLE_SLEEP );
 259                 continue;
 260             }
 261
 262             i_master_date = ntoh64(*(int64_t *)p_data);
 263             i_master_clockref = ntoh64(*(((int64_t *)p_data)+1));
 264
 265             i_diff_date = i_receive_date -
 266                           ((i_receive_date - i_send_date) / 2 + i_master_date);
 267
 268             i_client_clockref = i_drift = 0;
 269             if( p_input && i_master_clockref )
 270             {
 271                 i_client_clockref = GetClockRef( p_intf, i_clockref );
 272                 i_drift = i_client_clockref - i_master_clockref - i_diff_date;
 273
 274                 /* Update our clock to match the master's one */
 275                 if( i_client_clockref )
 276                     p_input->i_pts_delay -= i_drift;
 277             }
 278
 279 #if 0
 280             msg_Dbg( p_intf, "Slave clockref: %"PRId64" -> %"PRId64" -> %"PRId64", "
 281                      "clock diff: %"PRId64" drift: %"PRId64,
 282                      i_clockref, i_master_clockref,
 283                      i_client_clockref, i_diff_date, i_drift );
 284 #endif
 285
 286             /* Wait a bit */
 287             msleep( INTF_IDLE_SLEEP );
 288         }
 289     }
 290
 291     if( p_input ) vlc_object_release( p_input );
 292     vlc_restorecancel( canc );
 293 }
 294
 295 static mtime_t GetClockRef( intf_thread_t *p_intf, mtime_t i_pts )
 296 {
 297     input_thread_t *p_input = p_intf->p_sys->p_input;
 298     mtime_t i_ts;
 299
 300     if( !p_input || !p_input->p->p_es_out ) return 0;
 301
 302     if( es_out_Control( p_input->p->p_es_out, ES_OUT_GET_TS, i_pts, &i_ts ) ==
 303         VLC_SUCCESS )
 304     {
 305         return i_ts;
 306     }
 307
 308     return 0;
 309 }