modules/access/srt.c

   1 /*****************************************************************************
   2  * srt.c: SRT (Secure Reliable Transport) input module
   3  *****************************************************************************
   4  * Copyright (C) 2017-2018, Collabora Ltd.
   5  * Copyright (C) 2018, Haivision Systems Inc.
   6  *
   7  * Authors: Justin Kim <justin.kim@collabora.com>
   8  *          Roman Diouskine <rdiouskine@haivision.com>
   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 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <vlc_common.h>
  30 #include <vlc_interrupt.h>
  31 #include <vlc_fs.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_access.h>
  34
  35 #include <vlc_network.h>
  36 #include <vlc_url.h>
  37
  38 #include <srt/srt.h>
  39
  40 /* libsrt defines default packet size as 1316 internally
  41  * so srt module takes same value. */
  42 #define SRT_DEFAULT_CHUNK_SIZE 1316
  43 /* Minimum/Maximum chunks to allow reading at a time from libsrt */
  44 #define SRT_MIN_CHUNKS_TRYREAD 10
  45 #define SRT_MAX_CHUNKS_TRYREAD 100
  46 /* The default timeout is -1 (infinite) */
  47 #define SRT_DEFAULT_POLL_TIMEOUT -1
  48 /* The default latency is 125
  49  * which uses srt library internally */
  50 #define SRT_DEFAULT_LATENCY 125
  51 /* Crypto key length in bytes. */
  52 #define SRT_KEY_LENGTH_TEXT N_("Crypto key length in bytes")
  53 #define SRT_DEFAULT_KEY_LENGTH 16
  54 static const int srt_key_lengths[] = {
  55     16, 24, 32,
  56 };
  57
  58 static const char *const srt_key_length_names[] = {
  59     N_("16 bytes"), N_("24 bytes"), N_("32 bytes"),
  60 };
  61
  62 typedef struct
  63 {
  64     SRTSOCKET   sock;
  65     int         i_poll_id;
  66     vlc_mutex_t lock;
  67     bool        b_interrupted;
  68     char       *psz_host;
  69     int         i_port;
  70     int         i_chunks; /* Number of chunks to allocate in the next read */
  71 } stream_sys_t;
  72
  73 static void srt_wait_interrupted(void *p_data)
  74 {
  75     stream_t *p_stream = p_data;
  76     stream_sys_t *p_sys = p_stream->p_sys;
  77
  78     vlc_mutex_lock( &p_sys->lock );
  79     if ( p_sys->i_poll_id >= 0 &&  p_sys->sock != SRT_INVALID_SOCK )
  80     {
  81         p_sys->b_interrupted = true;
  82
  83         msg_Dbg( p_stream, "Waking up srt_epoll_wait");
  84
  85         /* Removing all socket descriptors from the monitoring list
  86          * wakes up SRT's threads. We only have one to remove. */
  87         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
  88     }
  89     vlc_mutex_unlock( &p_sys->lock );
  90 }
  91
  92 static int Control(stream_t *p_stream, int i_query, va_list args)
  93 {
  94     int i_ret = VLC_SUCCESS;
  95
  96     switch( i_query )
  97     {
  98         case STREAM_CAN_SEEK:
  99         case STREAM_CAN_FASTSEEK:
 100         case STREAM_CAN_PAUSE:
 101         case STREAM_CAN_CONTROL_PACE:
 102             *va_arg( args, bool * ) = false;
 103             break;
 104         case STREAM_GET_PTS_DELAY:
 105             *va_arg( args, vlc_tick_t * ) = VLC_TICK_FROM_MS(
 106                    var_InheritInteger(p_stream, "network-caching") );
 107             break;
 108         default:
 109             i_ret = VLC_EGENERIC;
 110             break;
 111     }
 112
 113     return i_ret;
 114 }
 115
 116 static bool srt_schedule_reconnect(stream_t *p_stream)
 117 {
 118     int         i_latency;
 119     int         stat;
 120     char        *psz_passphrase = NULL;
 121
 122     struct addrinfo hints = {
 123         .ai_socktype = SOCK_DGRAM,
 124     }, *res = NULL;
 125
 126     stream_sys_t *p_sys = p_stream->p_sys;
 127     bool failed = false;
 128
 129     stat = vlc_getaddrinfo( p_sys->psz_host, p_sys->i_port, &hints, &res );
 130     if ( stat )
 131     {
 132         msg_Err( p_stream, "Cannot resolve [%s]:%d (reason: %s)",
 133                  p_sys->psz_host,
 134                  p_sys->i_port,
 135                  gai_strerror( stat ) );
 136
 137         failed = true;
 138         goto out;
 139     }
 140
 141     /* Always start with a fresh socket */
 142     if (p_sys->sock != SRT_INVALID_SOCK)
 143     {
 144         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 145         srt_close( p_sys->sock );
 146     }
 147
 148     p_sys->sock = srt_socket( res->ai_family, SOCK_DGRAM, 0 );
 149     if ( p_sys->sock == SRT_INVALID_SOCK )
 150     {
 151         msg_Err( p_stream, "Failed to open socket." );
 152         failed = true;
 153         goto out;
 154     }
 155
 156     /* Make SRT non-blocking */
 157     srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN,
 158         &(bool) { false }, sizeof( bool ) );
 159     srt_setsockopt( p_sys->sock, 0, SRTO_RCVSYN,
 160         &(bool) { false }, sizeof( bool ) );
 161
 162     /* Make sure TSBPD mode is enable (SRT mode) */
 163     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDMODE,
 164         &(int) { 1 }, sizeof( int ) );
 165
 166     /* This is an access module so it is always a receiver */
 167     srt_setsockopt( p_sys->sock, 0, SRTO_SENDER,
 168         &(int) { 0 }, sizeof( int ) );
 169
 170     /* Set latency */
 171     i_latency = var_InheritInteger( p_stream, "latency" );
 172     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDDELAY,
 173         &i_latency, sizeof( int ) );
 174
 175     psz_passphrase = var_InheritString( p_stream, "passphrase" );
 176     if ( psz_passphrase != NULL && psz_passphrase[0] != '\0')
 177     {
 178         int i_key_length = var_InheritInteger( p_stream, "key-length" );
 179         srt_setsockopt( p_sys->sock, 0, SRTO_PASSPHRASE,
 180             psz_passphrase, strlen( psz_passphrase ) );
 181         srt_setsockopt( p_sys->sock, 0, SRTO_PBKEYLEN,
 182             &i_key_length, sizeof( int ) );
 183     }
 184
 185     srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock,
 186         &(int) { SRT_EPOLL_ERR | SRT_EPOLL_IN });
 187
 188     /* Schedule a connect */
 189     msg_Dbg( p_stream, "Schedule SRT connect (dest addresss: %s, port: %d).",
 190         p_sys->psz_host, p_sys->i_port);
 191
 192     stat = srt_connect( p_sys->sock, res->ai_addr, res->ai_addrlen);
 193     if ( stat == SRT_ERROR )
 194     {
 195         msg_Err( p_stream, "Failed to connect to server (reason: %s)",
 196                  srt_getlasterror_str() );
 197         failed = true;
 198     }
 199
 200     /* Reset the number of chunks to allocate as the bitrate of
 201      * the stream may have changed.
 202      */
 203     p_sys->i_chunks = SRT_MIN_CHUNKS_TRYREAD;
 204
 205 out:
 206     if (failed && p_sys->sock != SRT_INVALID_SOCK)
 207     {
 208         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 209         srt_close(p_sys->sock);
 210         p_sys->sock = SRT_INVALID_SOCK;
 211     }
 212
 213     freeaddrinfo( res );
 214     free( psz_passphrase );
 215
 216     return !failed;
 217 }
 218
 219 static block_t *BlockSRT(stream_t *p_stream, bool *restrict eof)
 220 {
 221     stream_sys_t *p_sys = p_stream->p_sys;
 222     int i_chunk_size = var_InheritInteger( p_stream, "chunk-size" );
 223     int i_poll_timeout = var_InheritInteger( p_stream, "poll-timeout" );
 224     /* SRT doesn't have a concept of EOF for live streams. */
 225     VLC_UNUSED(eof);
 226
 227     if ( vlc_killed() )
 228     {
 229         /* We are told to stop. Stop. */
 230         return NULL;
 231     }
 232
 233     if ( p_sys->i_chunks == 0 )
 234         p_sys->i_chunks = SRT_MIN_CHUNKS_TRYREAD;
 235
 236     size_t i_chunk_size_actual = ( i_chunk_size > 0 )
 237         ? i_chunk_size : SRT_DEFAULT_CHUNK_SIZE;
 238     size_t bufsize = i_chunk_size_actual * p_sys->i_chunks;
 239     block_t *pkt = block_Alloc( bufsize );
 240     if ( unlikely( pkt == NULL ) )
 241     {
 242         return NULL;
 243     }
 244
 245     vlc_interrupt_register( srt_wait_interrupted, p_stream);
 246
 247     SRTSOCKET ready[1];
 248     int readycnt = 1;
 249     while ( srt_epoll_wait( p_sys->i_poll_id,
 250         ready, &readycnt, 0, 0,
 251         i_poll_timeout, NULL, 0, NULL, 0 ) >= 0)
 252     {
 253         if ( readycnt < 0  || ready[0] != p_sys->sock )
 254         {
 255             /* should never happen, force recovery */
 256             srt_close(p_sys->sock);
 257             p_sys->sock = SRT_INVALID_SOCK;
 258         }
 259
 260         switch( srt_getsockstate( p_sys->sock ) )
 261         {
 262             case SRTS_CONNECTED:
 263                 /* Good to go */
 264                 break;
 265             case SRTS_BROKEN:
 266             case SRTS_NONEXIST:
 267             case SRTS_CLOSED:
 268                 /* Failed. Schedule recovery. */
 269                 if ( !srt_schedule_reconnect( p_stream ) )
 270                     msg_Err( p_stream, "Failed to schedule connect" );
 271                 /* Fall-through */
 272             default:
 273                 /* Not ready */
 274                 continue;
 275         }
 276
 277         /* Try to get as much data as possible out of the lib, if there
 278          * is still some left, increase the number of chunks to read so that
 279          * it will read faster on the next iteration. This way the buffer will
 280          * grow until it reads fast enough to keep the library empty after
 281          * each iteration.
 282          */
 283         pkt->i_buffer = 0;
 284         while ( ( bufsize - pkt->i_buffer ) >= i_chunk_size_actual )
 285         {
 286             int stat = srt_recvmsg( p_sys->sock,
 287                 (char *)( pkt->p_buffer + pkt->i_buffer ),
 288                 bufsize - pkt->i_buffer );
 289             if ( stat <= 0 )
 290             {
 291                 break;
 292             }
 293             pkt->i_buffer += (size_t)stat;
 294         }
 295
 296         msg_Dbg ( p_stream, "Read %zu bytes out of a max of %zu"
 297             " (%d chunks of %zu bytes)", pkt->i_buffer,
 298             p_sys->i_chunks * i_chunk_size_actual, p_sys->i_chunks,
 299                  i_chunk_size_actual );
 300
 301
 302         /* Gradually adjust number of chunks we read at a time
 303         * up to a predefined maximum. The actual number we might
 304         * settle on depends on stream's bit rate.
 305         */
 306         size_t rem = bufsize - pkt->i_buffer;
 307         if ( rem < i_chunk_size_actual )
 308         {
 309             if ( p_sys->i_chunks < SRT_MAX_CHUNKS_TRYREAD )
 310             {
 311                 p_sys->i_chunks++;
 312             }
 313         }
 314
 315         goto out;
 316     }
 317
 318     /* if the poll reports errors for any reason at all,
 319      * including a timeout, we skip the turn.
 320      */
 321     pkt->i_buffer = 0;
 322
 323 out:
 324     if (pkt->i_buffer == 0) {
 325       block_Release(pkt);
 326       pkt = NULL;
 327     }
 328
 329     vlc_interrupt_unregister();
 330
 331     /* Re-add the socket to the poll if we were interrupted */
 332     vlc_mutex_lock( &p_sys->lock );
 333     if ( p_sys->b_interrupted )
 334     {
 335         srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock,
 336             &(int) { SRT_EPOLL_ERR | SRT_EPOLL_IN } );
 337         p_sys->b_interrupted = false;
 338     }
 339     vlc_mutex_unlock( &p_sys->lock );
 340
 341     return pkt;
 342 }
 343
 344 static int Open(vlc_object_t *p_this)
 345 {
 346     stream_t     *p_stream = (stream_t*)p_this;
 347     stream_sys_t *p_sys = NULL;
 348     vlc_url_t     parsed_url = { 0 };
 349
 350     p_sys = vlc_obj_calloc( p_this, 1, sizeof( *p_sys ) );
 351     if( unlikely( p_sys == NULL ) )
 352         return VLC_ENOMEM;
 353
 354     srt_startup();
 355
 356     vlc_mutex_init( &p_sys->lock );
 357
 358     p_stream->p_sys = p_sys;
 359
 360     if ( vlc_UrlParse( &parsed_url, p_stream->psz_url ) == -1 )
 361     {
 362         msg_Err( p_stream, "Failed to parse input URL (%s)",
 363             p_stream->psz_url );
 364         goto failed;
 365     }
 366
 367     p_sys->psz_host = vlc_obj_strdup( p_this, parsed_url.psz_host );
 368     p_sys->i_port = parsed_url.i_port;
 369
 370     vlc_UrlClean( &parsed_url );
 371
 372     p_sys->i_poll_id = srt_epoll_create();
 373     if ( p_sys->i_poll_id == -1 )
 374     {
 375         msg_Err( p_stream, "Failed to create poll id for SRT socket." );
 376         goto failed;
 377     }
 378
 379     if ( !srt_schedule_reconnect( p_stream ) )
 380     {
 381         msg_Err( p_stream, "Failed to schedule connect");
 382
 383         goto failed;
 384     }
 385
 386     p_stream->pf_block = BlockSRT;
 387     p_stream->pf_control = Control;
 388
 389     return VLC_SUCCESS;
 390
 391 failed:
 392     vlc_mutex_destroy( &p_sys->lock );
 393
 394     if ( p_sys->sock != -1 ) srt_close( p_sys->sock );
 395     if ( p_sys->i_poll_id != -1 ) srt_epoll_release( p_sys->i_poll_id );
 396
 397     return VLC_EGENERIC;
 398 }
 399
 400 static void Close(vlc_object_t *p_this)
 401 {
 402     stream_t     *p_stream = (stream_t*)p_this;
 403     stream_sys_t *p_sys = p_stream->p_sys;
 404
 405     vlc_mutex_destroy( &p_sys->lock );
 406
 407     srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 408     srt_close( p_sys->sock );
 409     srt_epoll_release( p_sys->i_poll_id );
 410
 411     srt_cleanup();
 412 }
 413
 414 /* Module descriptor */
 415 vlc_module_begin ()
 416     set_shortname( N_("SRT") )
 417     set_description( N_("SRT input") )
 418     set_category( CAT_INPUT )
 419     set_subcategory( SUBCAT_INPUT_ACCESS )
 420
 421     add_integer( "chunk-size", SRT_DEFAULT_CHUNK_SIZE,
 422             N_("SRT chunk size (bytes)"), NULL, true )
 423     add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT,
 424             N_("Return poll wait after timeout milliseconds (-1 = infinite)"), NULL, true )
 425     add_integer( "latency", SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
 426     add_password("passphrase", "", N_("Password for stream encryption"), NULL)
 427     add_integer( "key-length", SRT_DEFAULT_KEY_LENGTH,
 428             SRT_KEY_LENGTH_TEXT, SRT_KEY_LENGTH_TEXT, false )
 429         change_integer_list( srt_key_lengths, srt_key_length_names )
 430
 431     set_capability( "access", 0 )
 432     add_shortcut( "srt" )
 433
 434     set_callbacks( Open, Close )
 435 vlc_module_end ()