src/stream_output/sap.c

   1 /*****************************************************************************
   2  * sap.c : SAP announce handler
   3  *****************************************************************************
   4  * Copyright (C) 2002-2008 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 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <vlc_common.h>
  34
  35 #include <stdlib.h>                                                /* free() */
  36 #include <stdio.h>                                              /* sprintf() */
  37 #include <string.h>
  38 #include <assert.h>
  39
  40 #include <vlc_sout.h>
  41 #include <vlc_network.h>
  42
  43 #include "stream_output.h"
  44 #include "libvlc.h"
  45
  46 /* SAP is always on that port */
  47 #define IPPORT_SAP 9875
  48
  49 /* A SAP session descriptor, enqueued in the SAP handler queue */
  50 typedef struct sap_session_t
  51 {
  52     struct sap_session_t *next;
  53     const session_descriptor_t *p_sd;
  54     size_t                length;
  55     uint8_t               data[];
  56 } sap_session_t;
  57
  58 /* A SAP announce address. For each of these, we run the
  59  * control flow algorithm */
  60 typedef struct sap_address_t
  61 {
  62     struct sap_address_t   *next;
  63
  64     vlc_thread_t            thread;
  65     vlc_mutex_t             lock;
  66     vlc_cond_t              wait;
  67
  68     char                    group[NI_MAXNUMERICHOST];
  69     struct sockaddr_storage orig;
  70     socklen_t               origlen;
  71     int                     fd;
  72     unsigned                interval;
  73
  74     unsigned                session_count;
  75     sap_session_t          *first;
  76 } sap_address_t;
  77
  78 /* The SAP handler, running in a separate thread */
  79 struct sap_handler_t
  80 {
  81     VLC_COMMON_MEMBERS
  82
  83     vlc_mutex_t    lock;
  84     sap_address_t *first;
  85 };
  86
  87 #define SAP_MAX_BUFFER 65534
  88 #define MIN_INTERVAL 2
  89 #define MAX_INTERVAL 300
  90
  91 /*****************************************************************************
  92  * Local prototypes
  93  *****************************************************************************/
  94 static void *RunThread (void *);
  95
  96 /**
  97  * Create the SAP handler
  98  *
  99  * \param p_announce a VLC object
 100  * \return the newly created SAP handler or NULL on error
 101  */
 102 sap_handler_t *SAP_Create (vlc_object_t *p_announce)
 103 {
 104     sap_handler_t *p_sap;
 105
 106     p_sap = vlc_custom_create (p_announce, sizeof (*p_sap),
 107                                VLC_OBJECT_GENERIC, "sap sender");
 108     if (p_sap == NULL)
 109         return NULL;
 110
 111     vlc_mutex_init (&p_sap->lock);
 112     p_sap->first = NULL;
 113     return p_sap;
 114 }
 115
 116 void SAP_Destroy (sap_handler_t *p_sap)
 117 {
 118     assert (p_sap->first == NULL);
 119     vlc_mutex_destroy (&p_sap->lock);
 120     vlc_object_release (p_sap);
 121 }
 122
 123 static sap_address_t *AddressCreate (vlc_object_t *obj, const char *group)
 124 {
 125     int fd = net_ConnectUDP (obj, group, IPPORT_SAP, 255);
 126     if (fd == -1)
 127         return NULL;
 128
 129     sap_address_t *addr = malloc (sizeof (*addr));
 130     if (addr == NULL)
 131     {
 132         net_Close (fd);
 133         return NULL;
 134     }
 135
 136     strlcpy (addr->group, group, sizeof (addr->group));
 137     addr->fd = fd;
 138     addr->origlen = sizeof (addr->orig);
 139     getsockname (fd, (struct sockaddr *)&addr->orig, &addr->origlen);
 140
 141     addr->interval = var_CreateGetInteger (obj, "sap-interval");
 142     vlc_mutex_init (&addr->lock);
 143     vlc_cond_init (&addr->wait);
 144     addr->session_count = 0;
 145     addr->first = NULL;
 146
 147     if (vlc_clone (&addr->thread, RunThread, addr, VLC_THREAD_PRIORITY_LOW))
 148     {
 149         msg_Err (obj, "unable to spawn SAP announce thread");
 150         net_Close (fd);
 151         free (addr);
 152         return NULL;
 153     }
 154     return addr;
 155 }
 156
 157 static void AddressDestroy (sap_address_t *addr)
 158 {
 159     assert (addr->first == NULL);
 160
 161     vlc_cancel (addr->thread);
 162     vlc_join (addr->thread, NULL);
 163     vlc_cond_destroy (&addr->wait);
 164     vlc_mutex_destroy (&addr->lock);
 165     net_Close (addr->fd);
 166     free (addr);
 167 }
 168
 169 /**
 170  * main SAP handler thread
 171  * \param p_this the SAP Handler object
 172  * \return nothing
 173  */
 174 static void *RunThread (void *self)
 175 {
 176     sap_address_t *addr = self;
 177
 178     vlc_mutex_lock (&addr->lock);
 179     mutex_cleanup_push (&addr->lock);
 180
 181     for (;;)
 182     {
 183         sap_session_t *p_session;
 184         mtime_t deadline;
 185
 186         while (addr->first == NULL)
 187             vlc_cond_wait (&addr->wait, &addr->lock);
 188
 189         assert (addr->session_count > 0);
 190
 191         deadline = mdate ();
 192         for (p_session = addr->first; p_session; p_session = p_session->next)
 193         {
 194             send (addr->fd, p_session->data, p_session->length, 0);
 195             deadline += addr->interval * CLOCK_FREQ / addr->session_count;
 196
 197             if (vlc_cond_timedwait (&addr->wait, &addr->lock, deadline) == 0)
 198                 break; /* list may have changed! */
 199         }
 200     }
 201
 202     vlc_cleanup_pop ();
 203     assert (0);
 204 }
 205
 206 /**
 207  * Add a SAP announce
 208  */
 209 int SAP_Add (sap_handler_t *p_sap, session_descriptor_t *p_session)
 210 {
 211     int i;
 212     char psz_addr[NI_MAXNUMERICHOST];
 213     bool b_ipv6 = false, b_ssm = false;
 214     sap_session_t *p_sap_session;
 215     mtime_t i_hash;
 216     union
 217     {
 218         struct sockaddr     a;
 219         struct sockaddr_in  in;
 220         struct sockaddr_in6 in6;
 221     } addr;
 222     socklen_t addrlen;
 223
 224     addrlen = p_session->addrlen;
 225     if ((addrlen == 0) || (addrlen > sizeof (addr)))
 226     {
 227         msg_Err( p_sap, "No/invalid address specified for SAP announce" );
 228         return VLC_EGENERIC;
 229     }
 230
 231     /* Determine SAP multicast address automatically */
 232     memcpy (&addr, &p_session->addr, addrlen);
 233
 234     switch (addr.a.sa_family)
 235     {
 236 #if defined (HAVE_INET_PTON) || defined (WIN32)
 237         case AF_INET6:
 238         {
 239             /* See RFC3513 for list of valid IPv6 scopes */
 240             struct in6_addr *a6 = &addr.in6.sin6_addr;
 241
 242             memcpy( a6->s6_addr + 2, "\x00\x00\x00\x00\x00\x00"
 243                    "\x00\x00\x00\x00\x00\x02\x7f\xfe", 14 );
 244             if( IN6_IS_ADDR_MULTICAST( a6 ) )
 245             {
 246                 /* SSM <=> ff3x::/32 */
 247                 b_ssm = (U32_AT (a6->s6_addr) & 0xfff0ffff) == 0xff300000;
 248
 249                 /* force flags to zero, preserve scope */
 250                 a6->s6_addr[1] &= 0xf;
 251             }
 252             else
 253                 /* Unicast IPv6 - assume global scope */
 254                 memcpy( a6->s6_addr, "\xff\x0e", 2 );
 255
 256             b_ipv6 = true;
 257             break;
 258         }
 259 #endif
 260
 261         case AF_INET:
 262         {
 263             /* See RFC2365 for IPv4 scopes */
 264             uint32_t ipv4 = addr.in.sin_addr.s_addr;
 265
 266             /* 224.0.0.0/24 => 224.0.0.255 */
 267             if ((ipv4 & htonl (0xffffff00)) == htonl (0xe0000000))
 268                 ipv4 =  htonl (0xe00000ff);
 269             else
 270             /* 239.255.0.0/16 => 239.255.255.255 */
 271             if ((ipv4 & htonl (0xffff0000)) == htonl (0xefff0000))
 272                 ipv4 =  htonl (0xefffffff);
 273             else
 274             /* 239.192.0.0/14 => 239.195.255.255 */
 275             if ((ipv4 & htonl (0xfffc0000)) == htonl (0xefc00000))
 276                 ipv4 =  htonl (0xefc3ffff);
 277             else
 278             if ((ipv4 & htonl (0xff000000)) == htonl (0xef000000))
 279                 ipv4 = 0;
 280             else
 281             /* other addresses => 224.2.127.254 */
 282             {
 283                 /* SSM: 232.0.0.0/8 */
 284                 b_ssm = (ipv4 & htonl (255 << 24)) == htonl (232 << 24);
 285                 ipv4 = htonl (0xe0027ffe);
 286             }
 287
 288             if( ipv4 == 0 )
 289             {
 290                 msg_Err( p_sap, "Out-of-scope multicast address "
 291                          "not supported by SAP" );
 292                 return VLC_EGENERIC;
 293             }
 294
 295             addr.in.sin_addr.s_addr = ipv4;
 296             break;
 297         }
 298
 299         default:
 300             msg_Err( p_sap, "Address family %d not supported by SAP",
 301                      addr.a.sa_family );
 302             return VLC_EGENERIC;
 303     }
 304
 305     i = vlc_getnameinfo( &addr.a, addrlen,
 306                          psz_addr, sizeof( psz_addr ), NULL, NI_NUMERICHOST );
 307
 308     if( i )
 309     {
 310         msg_Err( p_sap, "%s", gai_strerror( i ) );
 311         return VLC_EGENERIC;
 312     }
 313
 314     /* Find/create SAP address thread */
 315     msg_Dbg( p_sap, "using SAP address: %s", psz_addr);
 316
 317     vlc_mutex_lock (&p_sap->lock);
 318     sap_address_t *sap_addr;
 319     for (sap_addr = p_sap->first; sap_addr; sap_addr = sap_addr->next)
 320         if (!strcmp (psz_addr, sap_addr->group))
 321             break;
 322
 323     if (sap_addr == NULL)
 324     {
 325         sap_addr = AddressCreate (VLC_OBJECT(p_sap), psz_addr);
 326         if (sap_addr == NULL)
 327         {
 328             vlc_mutex_unlock (&p_sap->lock);
 329             return VLC_EGENERIC;
 330         }
 331         sap_addr->next = p_sap->first;
 332         p_sap->first = sap_addr;
 333     }
 334     /* Switch locks.
 335      * NEVER take the global SAP lock when holding a SAP thread lock! */
 336     vlc_mutex_lock (&sap_addr->lock);
 337     vlc_mutex_unlock (&p_sap->lock);
 338
 339     memcpy (&p_session->orig, &sap_addr->orig, sap_addr->origlen);
 340     p_session->origlen = sap_addr->origlen;
 341
 342     size_t headsize = 20, length;
 343     switch (p_session->orig.ss_family)
 344     {
 345 #ifdef AF_INET6
 346         case AF_INET6:
 347             headsize += 16;
 348             break;
 349 #endif
 350         case AF_INET:
 351             headsize += 4;
 352             break;
 353         default:
 354             assert (0);
 355     }
 356
 357     /* XXX: Check for dupes */
 358     length = headsize + strlen (p_session->psz_sdp);
 359     p_sap_session = malloc (sizeof (*p_sap_session) + length + 1);
 360     if (p_sap_session == NULL)
 361     {
 362         vlc_mutex_unlock (&sap_addr->lock);
 363         return VLC_EGENERIC; /* NOTE: we should destroy the thread if left unused */
 364     }
 365     p_sap_session->next = sap_addr->first;
 366     sap_addr->first = p_sap_session;
 367     p_sap_session->p_sd = p_session;
 368     p_sap_session->length = length;
 369
 370     /* Build the SAP Headers */
 371     uint8_t *psz_head = p_sap_session->data;
 372
 373     /* SAPv1, not encrypted, not compressed */
 374     psz_head[0] = 0x20;
 375     psz_head[1] = 0x00; /* No authentication length */
 376
 377     i_hash = mdate();
 378     psz_head[2] = i_hash >> 8; /* Msg id hash */
 379     psz_head[3] = i_hash;      /* Msg id hash 2 */
 380
 381     headsize = 4;
 382     switch (p_session->orig.ss_family)
 383     {
 384 #ifdef AF_INET6
 385         case AF_INET6:
 386         {
 387             struct in6_addr *a6 =
 388                 &((struct sockaddr_in6 *)&p_session->orig)->sin6_addr;
 389             memcpy (psz_head + headsize, a6, 16);
 390             psz_head[0] |= 0x10; /* IPv6 flag */
 391             headsize += 16;
 392             break;
 393         }
 394 #endif
 395         case AF_INET:
 396         {
 397             uint32_t ipv4 =
 398                 (((struct sockaddr_in *)&p_session->orig)->sin_addr.s_addr);
 399             memcpy (psz_head + headsize, &ipv4, 4);
 400             headsize += 4;
 401             break;
 402         }
 403
 404     }
 405
 406     memcpy (psz_head + headsize, "application/sdp", 16);
 407     headsize += 16;
 408
 409     /* Build the final message */
 410     strcpy( (char *)psz_head + headsize, p_session->psz_sdp);
 411
 412     sap_addr->session_count++;
 413     vlc_cond_signal (&sap_addr->wait);
 414     vlc_mutex_unlock (&sap_addr->lock);
 415     return VLC_SUCCESS;
 416 }
 417
 418 /**
 419  * Remove a SAP Announce
 420  */
 421 void SAP_Del (sap_handler_t *p_sap, const session_descriptor_t *p_session)
 422 {
 423     vlc_mutex_lock (&p_sap->lock);
 424
 425     /* TODO: give a handle back in SAP_Add, and use that... */
 426     sap_address_t *addr, **paddr;
 427     sap_session_t *session, **psession;
 428
 429     paddr = &p_sap->first;
 430     for (addr = p_sap->first; addr; addr = addr->next)
 431     {
 432         psession = &addr->first;
 433         vlc_mutex_lock (&addr->lock);
 434         for (session = addr->first; session; session = session->next)
 435         {
 436             if (session->p_sd == p_session)
 437                 goto found;
 438             psession = &session->next;
 439         }
 440         vlc_mutex_unlock (&addr->lock);
 441         paddr = &addr->next;
 442     }
 443     assert (0);
 444
 445 found:
 446     *psession = session->next;
 447
 448     if (addr->first == NULL)
 449         /* Last session for this address -> unlink the address */
 450         *paddr = addr->next;
 451     vlc_mutex_unlock (&p_sap->lock);
 452
 453     if (addr->first == NULL)
 454     {
 455         /* Last session for this address -> unlink the address */
 456         vlc_mutex_unlock (&addr->lock);
 457         AddressDestroy (addr);
 458     }
 459     else
 460     {
 461         addr->session_count--;
 462         vlc_cond_signal (&addr->wait);
 463         vlc_mutex_unlock (&addr->lock);
 464     }
 465
 466     free (session);
 467 }