src/stream_output/sap.c

   1 /*****************************************************************************
   2  * sap.c : SAP announce handler
   3  *****************************************************************************
   4  * Copyright (C) 2002-2008 VLC authors and VideoLAN
   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 it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * 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), "sap sender");
 107     if (p_sap == NULL)
 108         return NULL;
 109
 110     vlc_mutex_init (&p_sap->lock);
 111     p_sap->first = NULL;
 112     return p_sap;
 113 }
 114
 115 void SAP_Destroy (sap_handler_t *p_sap)
 116 {
 117     assert (p_sap->first == NULL);
 118     vlc_mutex_destroy (&p_sap->lock);
 119     vlc_object_release (p_sap);
 120 }
 121
 122 static sap_address_t *AddressCreate (vlc_object_t *obj, const char *group)
 123 {
 124     int fd = net_ConnectUDP (obj, group, IPPORT_SAP, 255);
 125     if (fd == -1)
 126         return NULL;
 127
 128     sap_address_t *addr = malloc (sizeof (*addr));
 129     if (addr == NULL)
 130     {
 131         net_Close (fd);
 132         return NULL;
 133     }
 134
 135     strlcpy (addr->group, group, sizeof (addr->group));
 136     addr->fd = fd;
 137     addr->origlen = sizeof (addr->orig);
 138     getsockname (fd, (struct sockaddr *)&addr->orig, &addr->origlen);
 139
 140     addr->interval = var_CreateGetInteger (obj, "sap-interval");
 141     vlc_mutex_init (&addr->lock);
 142     vlc_cond_init (&addr->wait);
 143     addr->session_count = 0;
 144     addr->first = NULL;
 145
 146     if (vlc_clone (&addr->thread, RunThread, addr, VLC_THREAD_PRIORITY_LOW))
 147     {
 148         msg_Err (obj, "unable to spawn SAP announce thread");
 149         net_Close (fd);
 150         free (addr);
 151         return NULL;
 152     }
 153     return addr;
 154 }
 155
 156 static void AddressDestroy (sap_address_t *addr)
 157 {
 158     assert (addr->first == NULL);
 159
 160     vlc_cancel (addr->thread);
 161     vlc_join (addr->thread, NULL);
 162     vlc_cond_destroy (&addr->wait);
 163     vlc_mutex_destroy (&addr->lock);
 164     net_Close (addr->fd);
 165     free (addr);
 166 }
 167
 168 /**
 169  * main SAP handler thread
 170  * \param p_this the SAP Handler object
 171  * \return nothing
 172  */
 173 VLC_NORETURN
 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     sap_session_t *p_sap_session;
 214     mtime_t i_hash;
 215     union
 216     {
 217         struct sockaddr     a;
 218         struct sockaddr_in  in;
 219         struct sockaddr_in6 in6;
 220     } addr;
 221     socklen_t addrlen;
 222
 223     addrlen = p_session->addrlen;
 224     if ((addrlen == 0) || (addrlen > sizeof (addr)))
 225     {
 226         msg_Err( p_sap, "No/invalid address specified for SAP announce" );
 227         return VLC_EGENERIC;
 228     }
 229
 230     /* Determine SAP multicast address automatically */
 231     memcpy (&addr, &p_session->addr, addrlen);
 232
 233     switch (addr.a.sa_family)
 234     {
 235 #if defined (HAVE_INET_PTON) || defined (_WIN32)
 236         case AF_INET6:
 237         {
 238             /* See RFC3513 for list of valid IPv6 scopes */
 239             struct in6_addr *a6 = &addr.in6.sin6_addr;
 240
 241             memcpy( a6->s6_addr + 2, "\x00\x00\x00\x00\x00\x00"
 242                    "\x00\x00\x00\x00\x00\x02\x7f\xfe", 14 );
 243             if( IN6_IS_ADDR_MULTICAST( a6 ) )
 244                 /* force flags to zero, preserve scope */
 245                 a6->s6_addr[1] &= 0xf;
 246             else
 247                 /* Unicast IPv6 - assume global scope */
 248                 memcpy( a6->s6_addr, "\xff\x0e", 2 );
 249             break;
 250         }
 251 #endif
 252
 253         case AF_INET:
 254         {
 255             /* See RFC2365 for IPv4 scopes */
 256             uint32_t ipv4 = addr.in.sin_addr.s_addr;
 257
 258             /* 224.0.0.0/24 => 224.0.0.255 */
 259             if ((ipv4 & htonl (0xffffff00)) == htonl (0xe0000000))
 260                 ipv4 =  htonl (0xe00000ff);
 261             else
 262             /* 239.255.0.0/16 => 239.255.255.255 */
 263             if ((ipv4 & htonl (0xffff0000)) == htonl (0xefff0000))
 264                 ipv4 =  htonl (0xefffffff);
 265             else
 266             /* 239.192.0.0/14 => 239.195.255.255 */
 267             if ((ipv4 & htonl (0xfffc0000)) == htonl (0xefc00000))
 268                 ipv4 =  htonl (0xefc3ffff);
 269             else
 270             if ((ipv4 & htonl (0xff000000)) == htonl (0xef000000))
 271                 ipv4 = 0;
 272             else
 273             /* other addresses => 224.2.127.254 */
 274                 ipv4 = htonl (0xe0027ffe);
 275
 276             if( ipv4 == 0 )
 277             {
 278                 msg_Err( p_sap, "Out-of-scope multicast address "
 279                          "not supported by SAP" );
 280                 return VLC_EGENERIC;
 281             }
 282
 283             addr.in.sin_addr.s_addr = ipv4;
 284             break;
 285         }
 286
 287         default:
 288             msg_Err( p_sap, "Address family %d not supported by SAP",
 289                      addr.a.sa_family );
 290             return VLC_EGENERIC;
 291     }
 292
 293     i = vlc_getnameinfo( &addr.a, addrlen,
 294                          psz_addr, sizeof( psz_addr ), NULL, NI_NUMERICHOST );
 295
 296     if( i )
 297     {
 298         msg_Err( p_sap, "%s", gai_strerror( i ) );
 299         return VLC_EGENERIC;
 300     }
 301
 302     /* Find/create SAP address thread */
 303     msg_Dbg( p_sap, "using SAP address: %s", psz_addr);
 304
 305     vlc_mutex_lock (&p_sap->lock);
 306     sap_address_t *sap_addr;
 307     for (sap_addr = p_sap->first; sap_addr; sap_addr = sap_addr->next)
 308         if (!strcmp (psz_addr, sap_addr->group))
 309             break;
 310
 311     if (sap_addr == NULL)
 312     {
 313         sap_addr = AddressCreate (VLC_OBJECT(p_sap), psz_addr);
 314         if (sap_addr == NULL)
 315         {
 316             vlc_mutex_unlock (&p_sap->lock);
 317             return VLC_EGENERIC;
 318         }
 319         sap_addr->next = p_sap->first;
 320         p_sap->first = sap_addr;
 321     }
 322     /* Switch locks.
 323      * NEVER take the global SAP lock when holding a SAP thread lock! */
 324     vlc_mutex_lock (&sap_addr->lock);
 325     vlc_mutex_unlock (&p_sap->lock);
 326
 327     memcpy (&p_session->orig, &sap_addr->orig, sap_addr->origlen);
 328     p_session->origlen = sap_addr->origlen;
 329
 330     size_t headsize = 20, length;
 331     switch (p_session->orig.ss_family)
 332     {
 333 #ifdef AF_INET6
 334         case AF_INET6:
 335             headsize += 16;
 336             break;
 337 #endif
 338         case AF_INET:
 339             headsize += 4;
 340             break;
 341         default:
 342             assert (0);
 343     }
 344
 345     /* XXX: Check for dupes */
 346     length = headsize + strlen (p_session->psz_sdp);
 347     p_sap_session = malloc (sizeof (*p_sap_session) + length + 1);
 348     if (p_sap_session == NULL)
 349     {
 350         vlc_mutex_unlock (&sap_addr->lock);
 351         return VLC_EGENERIC; /* NOTE: we should destroy the thread if left unused */
 352     }
 353     p_sap_session->next = sap_addr->first;
 354     sap_addr->first = p_sap_session;
 355     p_sap_session->p_sd = p_session;
 356     p_sap_session->length = length;
 357
 358     /* Build the SAP Headers */
 359     uint8_t *psz_head = p_sap_session->data;
 360
 361     /* SAPv1, not encrypted, not compressed */
 362     psz_head[0] = 0x20;
 363     psz_head[1] = 0x00; /* No authentication length */
 364
 365     i_hash = mdate();
 366     psz_head[2] = i_hash >> 8; /* Msg id hash */
 367     psz_head[3] = i_hash;      /* Msg id hash 2 */
 368
 369     headsize = 4;
 370     switch (p_session->orig.ss_family)
 371     {
 372 #ifdef AF_INET6
 373         case AF_INET6:
 374         {
 375             struct in6_addr *a6 =
 376                 &((struct sockaddr_in6 *)&p_session->orig)->sin6_addr;
 377             memcpy (psz_head + headsize, a6, 16);
 378             psz_head[0] |= 0x10; /* IPv6 flag */
 379             headsize += 16;
 380             break;
 381         }
 382 #endif
 383         case AF_INET:
 384         {
 385             uint32_t ipv4 =
 386                 (((struct sockaddr_in *)&p_session->orig)->sin_addr.s_addr);
 387             memcpy (psz_head + headsize, &ipv4, 4);
 388             headsize += 4;
 389             break;
 390         }
 391
 392     }
 393
 394     memcpy (psz_head + headsize, "application/sdp", 16);
 395     headsize += 16;
 396
 397     /* Build the final message */
 398     strcpy( (char *)psz_head + headsize, p_session->psz_sdp);
 399
 400     sap_addr->session_count++;
 401     vlc_cond_signal (&sap_addr->wait);
 402     vlc_mutex_unlock (&sap_addr->lock);
 403     return VLC_SUCCESS;
 404 }
 405
 406 /**
 407  * Remove a SAP Announce
 408  */
 409 void SAP_Del (sap_handler_t *p_sap, const session_descriptor_t *p_session)
 410 {
 411     vlc_mutex_lock (&p_sap->lock);
 412
 413     /* TODO: give a handle back in SAP_Add, and use that... */
 414     sap_address_t *addr, **paddr;
 415     sap_session_t *session, **psession;
 416
 417     paddr = &p_sap->first;
 418     for (addr = p_sap->first; addr; addr = addr->next)
 419     {
 420         psession = &addr->first;
 421         vlc_mutex_lock (&addr->lock);
 422         for (session = addr->first; session; session = session->next)
 423         {
 424             if (session->p_sd == p_session)
 425                 goto found;
 426             psession = &session->next;
 427         }
 428         vlc_mutex_unlock (&addr->lock);
 429         paddr = &addr->next;
 430     }
 431     assert (0);
 432
 433 found:
 434     *psession = session->next;
 435
 436     if (addr->first == NULL)
 437         /* Last session for this address -> unlink the address */
 438         *paddr = addr->next;
 439     vlc_mutex_unlock (&p_sap->lock);
 440
 441     if (addr->first == NULL)
 442     {
 443         /* Last session for this address -> unlink the address */
 444         vlc_mutex_unlock (&addr->lock);
 445         AddressDestroy (addr);
 446     }
 447     else
 448     {
 449         addr->session_count--;
 450         vlc_cond_signal (&addr->wait);
 451         vlc_mutex_unlock (&addr->lock);
 452     }
 453
 454     free (session);
 455 }