git.sesse.net Git - vlc/blob - src/stream_output/sap.c

   1 /*****************************************************************************
   2  * sap.c : SAP announce handler
   3  *****************************************************************************
   4  * Copyright (C) 2002-2005 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Clément Stenac <zorglub@videolan.org>
   8  *          Rémi Denis-Courmont <rem # videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #include <vlc/vlc.h>
  30
  31 #include <stdlib.h>                                                /* free() */
  32 #include <stdio.h>                                              /* sprintf() */
  33 #include <string.h>                                            /* strerror() */
  34 #include <ctype.h>                                  /* tolower(), isxdigit() */
  35
  36 #include <vlc/sout.h>
  37
  38 #include "network.h"
  39 #include "charset.h"
  40
  41 /* SAP is always on that port */
  42 #define SAP_PORT 9875
  43
  44 #define DEFAULT_PORT "1234"
  45
  46 #undef EXTRA_DEBUG
  47
  48 /* SAP Specific structures */
  49
  50 /* 100ms */
  51 #define SAP_IDLE ((mtime_t)(0.100*CLOCK_FREQ))
  52 #define SAP_MAX_BUFFER 65534
  53 #define MIN_INTERVAL 2
  54 #define MAX_INTERVAL 300
  55
  56 /* A SAP announce address. For each of these, we run the
  57  * control flow algorithm */
  58 struct sap_address_t
  59 {
  60     char *psz_address;
  61     char psz_machine[NI_MAXNUMERICHOST];
  62     int i_rfd; /* Read socket */
  63     int i_wfd; /* Write socket */
  64
  65     /* Used for flow control */
  66     mtime_t t1;
  67     vlc_bool_t b_enabled;
  68     vlc_bool_t b_ready;
  69     int i_interval;
  70     int i_buff;
  71     int i_limit;
  72 };
  73
  74 /*****************************************************************************
  75  * Local prototypes
  76  *****************************************************************************/
  77 static void RunThread( vlc_object_t *p_this);
  78 static int CalculateRate( sap_handler_t *p_sap, sap_address_t *p_address );
  79 static char *SDPGenerate( sap_handler_t *p_sap,
  80                           const session_descriptor_t *p_session,
  81                           const sap_address_t *p_addr );
  82
  83 static int announce_SendSAPAnnounce( sap_handler_t *p_sap,
  84                                      sap_session_t *p_session );
  85
  86
  87 static int announce_SAPAnnounceAdd( sap_handler_t *p_sap,
  88                              session_descriptor_t *p_session );
  89
  90 static int announce_SAPAnnounceDel( sap_handler_t *p_sap,
  91                              session_descriptor_t *p_session );
  92
  93
  94 /**
  95  * Create the SAP handler
  96  *
  97  * \param p_announce the parent announce_handler
  98  * \return the newly created SAP handler or NULL on error
  99  */
 100 sap_handler_t *announce_SAPHandlerCreate( announce_handler_t *p_announce )
 101 {
 102     sap_handler_t *p_sap;
 103
 104     p_sap = vlc_object_create( p_announce, sizeof( sap_handler_t ) );
 105
 106     if( !p_sap )
 107     {
 108         msg_Err( p_announce, "out of memory" );
 109         return NULL;
 110     }
 111
 112     vlc_mutex_init( p_sap, &p_sap->object_lock );
 113
 114     p_sap->pf_add = announce_SAPAnnounceAdd;
 115     p_sap->pf_del = announce_SAPAnnounceDel;
 116
 117     p_sap->i_sessions = 0;
 118     p_sap->i_addresses = 0;
 119     p_sap->i_current_session = 0;
 120
 121     p_sap->b_control = config_GetInt( p_sap, "sap-flow-control");
 122
 123     if( vlc_thread_create( p_sap, "sap handler", RunThread,
 124                        VLC_THREAD_PRIORITY_LOW, VLC_FALSE ) )
 125     {
 126         msg_Dbg( p_announce, "unable to spawn SAP handler thread");
 127         free( p_sap );
 128         return NULL;
 129     };
 130     msg_Dbg( p_announce, "thread created, %i sessions", p_sap->i_sessions);
 131     return p_sap;
 132 }
 133
 134 /**
 135  *  Destroy the SAP handler
 136  *  \param p_this the SAP Handler to destroy
 137  *  \return nothing
 138  */
 139 void announce_SAPHandlerDestroy( sap_handler_t *p_sap )
 140 {
 141     int i;
 142
 143     vlc_mutex_destroy( &p_sap->object_lock );
 144
 145     /* Free the remaining sessions */
 146     for( i = 0 ; i< p_sap->i_sessions ; i++)
 147     {
 148         sap_session_t *p_session = p_sap->pp_sessions[i];
 149         FREENULL( p_session->psz_sdp );
 150         FREENULL( p_session->psz_data );
 151         REMOVE_ELEM( p_sap->pp_sessions, p_sap->i_sessions , i );
 152         FREENULL( p_session );
 153     }
 154
 155     /* Free the remaining addresses */
 156     for( i = 0 ; i< p_sap->i_addresses ; i++)
 157     {
 158         sap_address_t *p_address = p_sap->pp_addresses[i];
 159         FREENULL( p_address->psz_address );
 160         if( p_address->i_rfd > -1 )
 161         {
 162             net_Close( p_address->i_rfd );
 163         }
 164         if( p_address->i_wfd > -1 && p_sap->b_control )
 165         {
 166             net_Close( p_address->i_wfd );
 167         }
 168         REMOVE_ELEM( p_sap->pp_addresses, p_sap->i_addresses, i );
 169         FREENULL( p_address );
 170     }
 171
 172     /* Free the structure */
 173     vlc_object_destroy( p_sap );
 174 }
 175
 176 /**
 177  * main SAP handler thread
 178  * \param p_this the SAP Handler object
 179  * \return nothing
 180  */
 181 static void RunThread( vlc_object_t *p_this)
 182 {
 183     sap_handler_t *p_sap = (sap_handler_t*)p_this;
 184     sap_session_t *p_session;
 185
 186     while( !p_sap->b_die )
 187     {
 188         int i;
 189
 190         /* If needed, get the rate info */
 191         if( p_sap->b_control == VLC_TRUE )
 192         {
 193             for( i = 0 ; i< p_sap->i_addresses ; i++)
 194             {
 195                 if( p_sap->pp_addresses[i]->b_enabled == VLC_TRUE )
 196                 {
 197                     CalculateRate( p_sap, p_sap->pp_addresses[i] );
 198                 }
 199             }
 200         }
 201
 202         /* Find the session to announce */
 203         vlc_mutex_lock( &p_sap->object_lock );
 204         if( p_sap->i_sessions > p_sap->i_current_session + 1)
 205         {
 206             p_sap->i_current_session++;
 207         }
 208         else if( p_sap->i_sessions > 0)
 209         {
 210             p_sap->i_current_session = 0;
 211         }
 212         else
 213         {
 214             vlc_mutex_unlock( &p_sap->object_lock );
 215             msleep( SAP_IDLE );
 216             continue;
 217         }
 218         p_session = p_sap->pp_sessions[p_sap->i_current_session];
 219         vlc_mutex_unlock( &p_sap->object_lock );
 220
 221         /* And announce it */
 222         if( p_session->p_address->b_enabled == VLC_TRUE &&
 223             p_session->p_address->b_ready == VLC_TRUE )
 224         {
 225             announce_SendSAPAnnounce( p_sap, p_session );
 226         }
 227
 228         msleep( SAP_IDLE );
 229     }
 230 }
 231
 232 /* Add a SAP announce */
 233 static int announce_SAPAnnounceAdd( sap_handler_t *p_sap,
 234                              session_descriptor_t *p_session )
 235 {
 236     int i_header_size, i;
 237     char *psz_head, psz_addr[NI_MAXNUMERICHOST];
 238     vlc_bool_t b_ipv6 = VLC_FALSE;
 239     sap_session_t *p_sap_session;
 240     mtime_t i_hash;
 241     struct addrinfo hints, *res;
 242     struct sockaddr_storage addr;
 243     socklen_t addrlen;
 244
 245     vlc_mutex_lock( &p_sap->object_lock );
 246
 247     if( p_session->psz_uri == NULL )
 248     {
 249         vlc_mutex_unlock( &p_sap->object_lock );
 250         msg_Err( p_sap, "*FIXME* unexpected NULL URI for SAP announce" );
 251         msg_Err( p_sap, "This should not happen. VLC needs fixing." );
 252         return VLC_EGENERIC;
 253     }
 254
 255     /* Determine SAP multicast address automatically */
 256     memset( &hints, 0, sizeof( hints ) );
 257     hints.ai_socktype = SOCK_DGRAM;
 258     hints.ai_flags = AI_NUMERICHOST;
 259
 260     i = vlc_getaddrinfo( (vlc_object_t *)p_sap, p_session->psz_uri, 0,
 261                          &hints, &res );
 262     if( i )
 263     {
 264         vlc_mutex_unlock( &p_sap->object_lock );
 265         msg_Err( p_sap, "Invalid URI for SAP announce: %s: %s",
 266                  p_session->psz_uri, vlc_gai_strerror( i ) );
 267         return VLC_EGENERIC;
 268     }
 269
 270     addrlen = res->ai_addrlen;
 271     if ((unsigned)addrlen > sizeof (addr))
 272     {
 273         vlc_mutex_unlock( &p_sap->object_lock );
 274         vlc_freeaddrinfo( res );
 275         msg_Err( p_sap, "Unsupported address family of size %d > %u",
 276                  res->ai_addrlen, (unsigned) sizeof( addr ) );
 277         return VLC_EGENERIC;
 278     }
 279
 280     memcpy (&addr, res->ai_addr, addrlen);
 281     vlc_freeaddrinfo (res);
 282
 283     switch( addr.ss_family )
 284     {
 285 #if defined (HAVE_INET_PTON) || defined (WIN32)
 286         case AF_INET6:
 287         {
 288             /* See RFC3513 for list of valid IPv6 scopes */
 289             struct in6_addr *a6 = &((struct sockaddr_in6 *)&addr)->sin6_addr;
 290
 291             memcpy( a6->s6_addr + 2, "\x00\x00\x00\x00\x00\x00"
 292                    "\x00\x00\x00\x00\x00\x02\x7f\xfe", 14 );
 293             if( IN6_IS_ADDR_MULTICAST( a6 ) )
 294                  /* force flags to zero, preserve scope */
 295                 a6->s6_addr[1] &= 0xf;
 296             else
 297                 /* Unicast IPv6 - assume global scope */
 298                 memcpy( a6->s6_addr, "\xff\x0e", 2 );
 299
 300             b_ipv6 = VLC_TRUE;
 301             break;
 302         }
 303 #endif
 304
 305         case AF_INET:
 306         {
 307             /* See RFC2365 for IPv4 scopes */
 308             uint32_t ipv4;
 309
 310             ipv4 = ntohl( ((struct sockaddr_in *)&addr)->sin_addr.s_addr );
 311             /* 224.0.0.0/24 => 224.0.0.255 */
 312             if ((ipv4 & 0xffffff00) == 0xe0000000)
 313                 ipv4 =  0xe00000ff;
 314             else
 315             /* 239.255.0.0/16 => 239.255.255.255 */
 316             if ((ipv4 & 0xffff0000) == 0xefff0000)
 317                 ipv4 =  0xefffffff;
 318             else
 319             /* 239.192.0.0/14 => 239.195.255.255 */
 320             if ((ipv4 & 0xfffc0000) == 0xefc00000)
 321                 ipv4 =  0xefc3ffff;
 322             else
 323             if ((ipv4 & 0xff000000) == 0xef000000)
 324                 ipv4 = 0;
 325             else
 326             /* other addresses => 224.2.127.254 */
 327                 ipv4 = 0xe0027ffe;
 328
 329             if( ipv4 == 0 )
 330             {
 331                 msg_Err( p_sap, "Out-of-scope multicast address "
 332                         "not supported by SAP: %s", p_session->psz_uri );
 333                 vlc_mutex_unlock( &p_sap->object_lock );
 334                 return VLC_EGENERIC;
 335             }
 336
 337             ((struct sockaddr_in *)&addr)->sin_addr.s_addr = htonl( ipv4 );
 338             break;
 339         }
 340
 341         default:
 342             vlc_mutex_unlock( &p_sap->object_lock );
 343             msg_Err( p_sap, "Address family %d not supported by SAP",
 344                      addr.ss_family );
 345             return VLC_EGENERIC;
 346     }
 347
 348     i = vlc_getnameinfo( (struct sockaddr *)&addr, addrlen,
 349                          psz_addr, sizeof( psz_addr ), NULL, NI_NUMERICHOST );
 350
 351     if( i )
 352     {
 353         vlc_mutex_unlock( &p_sap->object_lock );
 354         msg_Err( p_sap, "%s", vlc_gai_strerror( i ) );
 355         return VLC_EGENERIC;
 356     }
 357
 358     msg_Dbg( p_sap, "using SAP address: %s", psz_addr);
 359
 360     /* XXX: Check for dupes */
 361     p_sap_session = (sap_session_t*)malloc(sizeof(sap_session_t));
 362     p_sap_session->p_address = NULL;
 363
 364     /* Add the address to the buffer */
 365     for( i = 0; i < p_sap->i_addresses; i++)
 366     {
 367         if( !strcmp( psz_addr, p_sap->pp_addresses[i]->psz_address ) )
 368         {
 369             p_sap_session->p_address = p_sap->pp_addresses[i];
 370             break;
 371         }
 372     }
 373
 374     if( p_sap_session->p_address == NULL )
 375     {
 376         sap_address_t *p_address = (sap_address_t *)
 377                                     malloc( sizeof(sap_address_t) );
 378         if( !p_address )
 379         {
 380             msg_Err( p_sap, "out of memory" );
 381             return VLC_ENOMEM;
 382         }
 383         p_address->psz_address = strdup( psz_addr );
 384         p_address->i_wfd = net_ConnectUDP( p_sap, psz_addr, SAP_PORT, 255 );
 385         if( p_address->i_wfd != -1 )
 386         {
 387             char *ptr;
 388
 389             net_StopRecv( p_address->i_wfd );
 390             net_GetSockAddress( p_address->i_wfd, p_address->psz_machine,
 391                                 NULL );
 392
 393             /* removes scope if present */
 394             ptr = strchr( p_address->psz_machine, '%' );
 395             if( ptr != NULL )
 396                 *ptr = '\0';
 397         }
 398
 399         if( p_sap->b_control == VLC_TRUE )
 400         {
 401             p_address->i_rfd = net_ListenUDP1( p_sap, psz_addr, SAP_PORT );
 402             if( p_address->i_rfd != -1 )
 403                 net_StopSend( p_address->i_rfd );
 404             p_address->i_buff = 0;
 405             p_address->b_enabled = VLC_TRUE;
 406             p_address->b_ready = VLC_FALSE;
 407             p_address->i_limit = 10000; /* 10000 bps */
 408             p_address->t1 = 0;
 409         }
 410         else
 411         {
 412             p_address->b_enabled = VLC_TRUE;
 413             p_address->b_ready = VLC_TRUE;
 414             p_address->i_interval = config_GetInt( p_sap,"sap-interval");
 415             p_address->i_rfd = -1;
 416         }
 417
 418         if( p_address->i_wfd == -1 || (p_address->i_rfd == -1
 419                                         && p_sap->b_control ) )
 420         {
 421             msg_Warn( p_sap, "disabling address" );
 422             p_address->b_enabled = VLC_FALSE;
 423         }
 424
 425         INSERT_ELEM( p_sap->pp_addresses,
 426                      p_sap->i_addresses,
 427                      p_sap->i_addresses,
 428                      p_address );
 429         p_sap_session->p_address = p_address;
 430     }
 431
 432
 433     /* Build the SAP Headers */
 434     i_header_size = ( b_ipv6 ? 16 : 4 ) + 20;
 435     psz_head = (char *) malloc( i_header_size * sizeof( char ) );
 436     if( psz_head == NULL )
 437     {
 438         msg_Err( p_sap, "out of memory" );
 439         return VLC_ENOMEM;
 440     }
 441
 442     /* SAPv1, not encrypted, not compressed */
 443     psz_head[0] = b_ipv6 ? 0x30 : 0x20;
 444     psz_head[1] = 0x00; /* No authentification length */
 445
 446     i_hash = mdate();
 447     psz_head[2] = (i_hash & 0xFF00) >> 8; /* Msg id hash */
 448     psz_head[3] = (i_hash & 0xFF);        /* Msg id hash 2 */
 449
 450 #if defined (HAVE_INET_PTON) || defined (WIN32)
 451     if( b_ipv6 )
 452     {
 453         inet_pton( AF_INET6, /* can't fail */
 454                    p_sap_session->p_address->psz_machine,
 455                    psz_head + 4 );
 456     }
 457     else
 458 #endif
 459     {
 460         inet_pton( AF_INET, /* can't fail */
 461                    p_sap_session->p_address->psz_machine,
 462                    psz_head + 4 );
 463     }
 464
 465     memcpy( psz_head + (b_ipv6 ? 20 : 8), "application/sdp", 15 );
 466
 467     /* If needed, build the SDP */
 468     if( p_session->psz_sdp == NULL )
 469     {
 470         p_session->psz_sdp = SDPGenerate( p_sap, p_session,
 471                                           p_sap_session->p_address );
 472         if( p_session->psz_sdp == NULL )
 473         {
 474             vlc_mutex_unlock( &p_sap->object_lock );
 475             return VLC_ENOMEM;
 476         }
 477     }
 478
 479     p_sap_session->psz_sdp = strdup( p_session->psz_sdp );
 480     p_sap_session->i_last = 0;
 481
 482     psz_head[ i_header_size-1 ] = '\0';
 483     p_sap_session->i_length = i_header_size + strlen( p_sap_session->psz_sdp);
 484
 485     p_sap_session->psz_data = (uint8_t *)malloc( sizeof(char)*
 486                                                  p_sap_session->i_length );
 487
 488     /* Build the final message */
 489     memcpy( p_sap_session->psz_data, psz_head, i_header_size );
 490     memcpy( p_sap_session->psz_data+i_header_size, p_sap_session->psz_sdp,
 491             strlen( p_sap_session->psz_sdp) );
 492
 493     free( psz_head );
 494
 495     /* Enqueue the announce */
 496     INSERT_ELEM( p_sap->pp_sessions,
 497                  p_sap->i_sessions,
 498                  p_sap->i_sessions,
 499                  p_sap_session );
 500     msg_Dbg( p_sap,"%i addresses, %i sessions",
 501                    p_sap->i_addresses,p_sap->i_sessions);
 502
 503     /* Remember the SAP session for later deletion */
 504     p_session->p_sap = p_sap_session;
 505
 506     vlc_mutex_unlock( &p_sap->object_lock );
 507
 508     return VLC_SUCCESS;
 509 }
 510
 511 /* Remove a SAP Announce */
 512 static int announce_SAPAnnounceDel( sap_handler_t *p_sap,
 513                              session_descriptor_t *p_session )
 514 {
 515     int i;
 516     vlc_mutex_lock( &p_sap->object_lock );
 517
 518     msg_Dbg( p_sap,"removing SAP announce %p",p_session->p_sap);
 519
 520     /* Dequeue the announce */
 521     for( i = 0; i< p_sap->i_sessions; i++)
 522     {
 523         if( p_session->p_sap == p_sap->pp_sessions[i] )
 524         {
 525             REMOVE_ELEM( p_sap->pp_sessions,
 526                          p_sap->i_sessions,
 527                          i );
 528
 529             FREENULL( p_session->p_sap->psz_sdp );
 530             FREENULL( p_session->p_sap->psz_data );
 531             free( p_session->p_sap );
 532             break;
 533         }
 534     }
 535
 536     /* XXX: Dequeue the address too if it is not used anymore
 537      * TODO: - address refcount
 538              - send a SAP deletion packet */
 539
 540     msg_Dbg( p_sap,"%i announcements remaining", p_sap->i_sessions );
 541
 542     vlc_mutex_unlock( &p_sap->object_lock );
 543
 544     return VLC_SUCCESS;
 545 }
 546
 547 static int announce_SendSAPAnnounce( sap_handler_t *p_sap,
 548                                      sap_session_t *p_session )
 549 {
 550     int i_ret;
 551
 552     /* This announce has never been sent yet */
 553     if( p_session->i_last == 0 )
 554     {
 555         p_session->i_next = mdate()+ p_session->p_address->i_interval*1000000;
 556         p_session->i_last = 1;
 557         return VLC_SUCCESS;
 558     }
 559
 560     if( p_session->i_next < mdate() )
 561     {
 562 #ifdef EXTRA_DEBUG
 563         msg_Dbg( p_sap, "sending announce");
 564 #endif
 565         i_ret = net_Write( p_sap, p_session->p_address->i_wfd, NULL,
 566                            p_session->psz_data,
 567                            p_session->i_length );
 568         if( i_ret != (int)p_session->i_length )
 569         {
 570             msg_Warn( p_sap, "SAP send failed on address %s (%i %i)",
 571                       p_session->p_address->psz_address,
 572                       i_ret, p_session->i_length );
 573         }
 574         p_session->i_last = p_session->i_next;
 575         p_session->i_next = p_session->i_last
 576                             + p_session->p_address->i_interval*1000000;
 577     }
 578     else
 579     {
 580         return VLC_SUCCESS;
 581     }
 582     return VLC_SUCCESS;
 583 }
 584
 585 static char *SDPGenerate( sap_handler_t *p_sap,
 586                           const session_descriptor_t *p_session,
 587                           const sap_address_t *p_addr )
 588 {
 589     int64_t i_sdp_id = mdate();
 590     int     i_sdp_version = 1 + p_sap->i_sessions + (rand()&0xfff);
 591     char *psz_group, *psz_name, psz_uribuf[NI_MAXNUMERICHOST], *psz_uri,
 592          *psz_sdp;
 593     char ipv;
 594
 595     psz_group = p_session->psz_group;
 596     psz_name = p_session->psz_name;
 597
 598     /* FIXME: really check that psz_uri is a real IP address
 599      * FIXME: make a common function to obtain a canonical IP address */
 600     ipv = ( strchr( p_session->psz_uri, ':' )  != NULL) ? '6' : '4';
 601     if( *p_session->psz_uri == '[' )
 602     {
 603         char *ptr;
 604
 605         strlcpy( psz_uribuf, p_session->psz_uri + 1, sizeof( psz_uribuf ) );
 606         ptr = strchr( psz_uribuf, '%' );
 607         if( ptr != NULL)
 608             *ptr = '\0';
 609         ptr = strchr( psz_uribuf, ']' );
 610         if( ptr != NULL)
 611             *ptr = '\0';
 612         psz_uri = psz_uribuf;
 613     }
 614     else
 615         psz_uri = p_session->psz_uri;
 616
 617     /* see the lists in modules/stream_out/rtp.c for compliance stuff */
 618     if( asprintf( &psz_sdp,
 619                             "v=0\r\n"
 620                             "o=- "I64Fd" %d IN IP%c %s\r\n"
 621                             "s=%s\r\n"
 622                             "c=IN IP%c %s/%d\r\n"
 623                             "t=0 0\r\n"
 624                             "a=tool:"PACKAGE_STRING"\r\n"
 625                             "a=recvonly\r\n"
 626                             "a=type:broadcast\n"
 627                             "a=source-filter: incl IN IP%c * %s\r\n"
 628                             "m=video %d %s %d\r\n"
 629                             "%s%s%s",
 630                             i_sdp_id, i_sdp_version,
 631                             ipv, p_addr->psz_machine,
 632                             psz_name, ipv, psz_uri,
 633                             /* FIXME: 1 is IPv4 default TTL, not that of IPv6 */
 634                             p_session->i_ttl ?: (config_GetInt( p_sap, "ttl" ) ?: 1),
 635                             ipv, psz_uri,
 636                             p_session->i_port,
 637                             p_session->b_rtp ? "RTP/AVP" : "udp",
 638                             p_session->i_payload,
 639                             psz_group ? "a=x-plgroup:" : "",
 640                             psz_group ? psz_group : "", psz_group ? "\r\n" : "" ) == -1 )
 641         return NULL;
 642
 643     msg_Dbg( p_sap, "Generated SDP (%i bytes):\n%s", strlen(psz_sdp),
 644              psz_sdp );
 645     return psz_sdp;
 646 }
 647
 648 static int CalculateRate( sap_handler_t *p_sap, sap_address_t *p_address )
 649 {
 650     int i_read;
 651     uint8_t buffer[SAP_MAX_BUFFER];
 652     int i_tot = 0;
 653     mtime_t i_temp;
 654     int i_rate;
 655
 656     if( p_address->t1 == 0 )
 657     {
 658         p_address->t1 = mdate();
 659         return VLC_SUCCESS;
 660     }
 661     do
 662     {
 663         /* Might be too slow if we have huge data */
 664         i_read = net_ReadNonBlock( p_sap, p_address->i_rfd, NULL, buffer,
 665                                    SAP_MAX_BUFFER, 0 );
 666         i_tot += i_read;
 667     } while( i_read > 0 );
 668
 669     i_temp = mdate();
 670
 671     /* We calculate the rate every 5 seconds */
 672     if( i_temp - p_address->t1 < 5000000 )
 673     {
 674         p_address->i_buff += i_tot;
 675         return VLC_SUCCESS;
 676     }
 677
 678     /* Bits/second */
 679     i_rate = (int)(8*1000000*((mtime_t)p_address->i_buff + (mtime_t)i_tot ) /
 680                         (i_temp - p_address->t1 ));
 681
 682     p_address->i_limit = 10000;
 683
 684     p_address->i_interval = ((1000*i_rate / p_address->i_limit) *
 685                             (MAX_INTERVAL - MIN_INTERVAL))/1000 + MIN_INTERVAL;
 686
 687     if( p_address->i_interval > MAX_INTERVAL || p_address->i_interval < 0 )
 688     {
 689         p_address->i_interval = MAX_INTERVAL;
 690     }
 691 #ifdef EXTRA_DEBUG
 692     msg_Dbg( p_sap,"%s:%i: rate=%i, interval = %i s",
 693              p_address->psz_address,SAP_PORT, i_rate, p_address->i_interval );
 694 #endif
 695
 696     p_address->b_ready = VLC_TRUE;
 697
 698     p_address->t1 = i_temp;
 699     p_address->i_buff = 0;
 700
 701     return VLC_SUCCESS;
 702 }