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 /* The default timeout is -1 (infinite) */
  44 #define SRT_DEFAULT_POLL_TIMEOUT -1
  45 /* The default latency is 125
  46  * which uses srt library internally */
  47 #define SRT_DEFAULT_LATENCY 125
  48 /* Crypto key length in bytes. */
  49 #define SRT_KEY_LENGTH_TEXT N_("Crypto key length in bytes")
  50 #define SRT_DEFAULT_KEY_LENGTH 16
  51 static const int srt_key_lengths[] = {
  52     16, 24, 32,
  53 };
  54
  55 static const char *const srt_key_length_names[] = {
  56     N_("16 bytes"), N_("24 bytes"), N_("32 bytes"),
  57 };
  58
  59 typedef struct
  60 {
  61     SRTSOCKET   sock;
  62     int         i_poll_id;
  63     vlc_mutex_t lock;
  64     bool        b_interrupted;
  65     char       *psz_host;
  66     int         i_port;
  67 } stream_sys_t;
  68
  69 static void srt_wait_interrupted(void *p_data)
  70 {
  71     stream_t *p_stream = p_data;
  72     stream_sys_t *p_sys = p_stream->p_sys;
  73
  74     vlc_mutex_lock( &p_sys->lock );
  75     if ( p_sys->i_poll_id >= 0 &&  p_sys->sock != SRT_INVALID_SOCK )
  76     {
  77         p_sys->b_interrupted = true;
  78
  79         msg_Dbg( p_stream, "Waking up srt_epoll_wait");
  80
  81         /* Removing all socket descriptors from the monitoring list
  82          * wakes up SRT's threads. We only have one to remove. */
  83         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
  84     }
  85     vlc_mutex_unlock( &p_sys->lock );
  86 }
  87
  88 static int Control(stream_t *p_stream, int i_query, va_list args)
  89 {
  90     int i_ret = VLC_SUCCESS;
  91
  92     switch( i_query )
  93     {
  94         case STREAM_CAN_SEEK:
  95         case STREAM_CAN_FASTSEEK:
  96         case STREAM_CAN_PAUSE:
  97         case STREAM_CAN_CONTROL_PACE:
  98             *va_arg( args, bool * ) = false;
  99             break;
 100         case STREAM_GET_PTS_DELAY:
 101             *va_arg( args, int64_t * ) = INT64_C(1000)
 102                    * var_InheritInteger(p_stream, "network-caching");
 103             break;
 104         default:
 105             i_ret = VLC_EGENERIC;
 106             break;
 107     }
 108
 109     return i_ret;
 110 }
 111
 112 static bool srt_schedule_reconnect(stream_t *p_stream)
 113 {
 114     int         i_latency;
 115     int         stat;
 116     char        *psz_passphrase = NULL;
 117
 118     struct addrinfo hints = {
 119         .ai_socktype = SOCK_DGRAM,
 120     }, *res = NULL;
 121
 122     stream_sys_t *p_sys = p_stream->p_sys;
 123     bool failed = false;
 124
 125     stat = vlc_getaddrinfo( p_sys->psz_host, p_sys->i_port, &hints, &res );
 126     if ( stat )
 127     {
 128         msg_Err( p_stream, "Cannot resolve [%s]:%d (reason: %s)",
 129                  p_sys->psz_host,
 130                  p_sys->i_port,
 131                  gai_strerror( stat ) );
 132
 133         failed = true;
 134         goto out;
 135     }
 136
 137     /* Always start with a fresh socket */
 138     if (p_sys->sock != SRT_INVALID_SOCK)
 139     {
 140         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 141         srt_close( p_sys->sock );
 142     }
 143
 144     p_sys->sock = srt_socket( res->ai_family, SOCK_DGRAM, 0 );
 145     if ( p_sys->sock == SRT_INVALID_SOCK )
 146     {
 147         msg_Err( p_stream, "Failed to open socket." );
 148         failed = true;
 149         goto out;
 150     }
 151
 152     /* Make SRT non-blocking */
 153     srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN,
 154         &(bool) { false }, sizeof( bool ) );
 155     srt_setsockopt( p_sys->sock, 0, SRTO_RCVSYN,
 156         &(bool) { false }, sizeof( bool ) );
 157
 158     /* Make sure TSBPD mode is enable (SRT mode) */
 159     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDMODE,
 160         &(int) { 1 }, sizeof( int ) );
 161
 162     /* This is an access module so it is always a receiver */
 163     srt_setsockopt( p_sys->sock, 0, SRTO_SENDER,
 164         &(int) { 0 }, sizeof( int ) );
 165
 166     /* Set latency */
 167     i_latency = var_InheritInteger( p_stream, "latency" );
 168     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDDELAY,
 169         &i_latency, sizeof( int ) );
 170
 171     psz_passphrase = var_InheritString( p_stream, "passphrase" );
 172     if ( psz_passphrase != NULL && psz_passphrase[0] != '\0')
 173     {
 174         int i_key_length = var_InheritInteger( p_stream, "key-length" );
 175         srt_setsockopt( p_sys->sock, 0, SRTO_PASSPHRASE,
 176             psz_passphrase, strlen( psz_passphrase ) );
 177         srt_setsockopt( p_sys->sock, 0, SRTO_PBKEYLEN,
 178             &i_key_length, sizeof( int ) );
 179     }
 180
 181     srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock,
 182         &(int) { SRT_EPOLL_ERR | SRT_EPOLL_IN });
 183
 184     /* Schedule a connect */
 185     msg_Dbg( p_stream, "Schedule SRT connect (dest addresss: %s, port: %d).",
 186         p_sys->psz_host, p_sys->i_port);
 187
 188     stat = srt_connect( p_sys->sock, res->ai_addr, res->ai_addrlen);
 189     if ( stat == SRT_ERROR )
 190     {
 191         msg_Err( p_stream, "Failed to connect to server (reason: %s)",
 192                  srt_getlasterror_str() );
 193         failed = true;
 194     }
 195
 196 out:
 197     if (failed && p_sys->sock != SRT_INVALID_SOCK)
 198     {
 199         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 200         srt_close(p_sys->sock);
 201         p_sys->sock = SRT_INVALID_SOCK;
 202     }
 203
 204     freeaddrinfo( res );
 205     free( psz_passphrase );
 206
 207     return !failed;
 208 }
 209
 210 static block_t *BlockSRT(stream_t *p_stream, bool *restrict eof)
 211 {
 212     stream_sys_t *p_sys = p_stream->p_sys;
 213     int i_chunk_size = var_InheritInteger( p_stream, "chunk-size" );
 214     int i_poll_timeout = var_InheritInteger( p_stream, "poll-timeout" );
 215
 216     if ( vlc_killed() )
 217     {
 218         /* We are told to stop. Stop. */
 219         return NULL;
 220     }
 221
 222     block_t *pkt = block_Alloc( i_chunk_size );
 223     if ( unlikely( pkt == NULL ) )
 224     {
 225         return NULL;
 226     }
 227
 228     vlc_interrupt_register( srt_wait_interrupted, p_stream);
 229
 230     SRTSOCKET ready[1];
 231     int readycnt = 1;
 232     while ( srt_epoll_wait( p_sys->i_poll_id,
 233         ready, &readycnt, 0, 0,
 234         i_poll_timeout, NULL, 0, NULL, 0 ) >= 0)
 235     {
 236         if ( readycnt < 0  || ready[0] != p_sys->sock )
 237         {
 238             /* should never happen, force recovery */
 239             srt_close(p_sys->sock);
 240             p_sys->sock = SRT_INVALID_SOCK;
 241         }
 242
 243         switch( srt_getsockstate( p_sys->sock ) )
 244         {
 245             case SRTS_CONNECTED:
 246                 /* Good to go */
 247                 break;
 248             case SRTS_BROKEN:
 249             case SRTS_NONEXIST:
 250             case SRTS_CLOSED:
 251                 /* Failed. Schedule recovery. */
 252                 if ( !srt_schedule_reconnect( p_stream ) )
 253                     msg_Err( p_stream, "Failed to schedule connect" );
 254                 /* Fall-through */
 255             default:
 256                 /* Not ready */
 257                 continue;
 258         }
 259
 260         int stat = srt_recvmsg( p_sys->sock,
 261             (char *)pkt->p_buffer, i_chunk_size );
 262         if ( stat > 0 )
 263         {
 264             pkt->i_buffer = stat;
 265             goto out;
 266         }
 267
 268         msg_Err( p_stream, "failed to receive packet, set EOS (reason: %s)",
 269             srt_getlasterror_str() );
 270         *eof = true;
 271         break;
 272     }
 273
 274     /* if the poll reports errors for any reason at all
 275      * including a timeout, or there is a read error,
 276      * we skip the turn.
 277      */
 278
 279     block_Release(pkt);
 280     pkt = NULL;
 281
 282 out:
 283     vlc_interrupt_unregister();
 284
 285     /* Re-add the socket to the poll if we were interrupted */
 286     vlc_mutex_lock( &p_sys->lock );
 287     if ( p_sys->b_interrupted )
 288     {
 289         srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock,
 290             &(int) { SRT_EPOLL_ERR | SRT_EPOLL_IN } );
 291         p_sys->b_interrupted = false;
 292     }
 293     vlc_mutex_unlock( &p_sys->lock );
 294
 295     return pkt;
 296 }
 297
 298 static int Open(vlc_object_t *p_this)
 299 {
 300     stream_t     *p_stream = (stream_t*)p_this;
 301     stream_sys_t *p_sys = NULL;
 302     vlc_url_t     parsed_url = { 0 };
 303
 304     p_sys = vlc_obj_calloc( p_this, 1, sizeof( *p_sys ) );
 305     if( unlikely( p_sys == NULL ) )
 306         return VLC_ENOMEM;
 307
 308     srt_startup();
 309
 310     vlc_mutex_init( &p_sys->lock );
 311
 312     p_stream->p_sys = p_sys;
 313
 314     if ( vlc_UrlParse( &parsed_url, p_stream->psz_url ) == -1 )
 315     {
 316         msg_Err( p_stream, "Failed to parse input URL (%s)",
 317             p_stream->psz_url );
 318         goto failed;
 319     }
 320
 321     p_sys->psz_host = strdup( parsed_url.psz_host );
 322     p_sys->i_port = parsed_url.i_port;
 323
 324     vlc_UrlClean( &parsed_url );
 325
 326     p_sys->i_poll_id = srt_epoll_create();
 327     if ( p_sys->i_poll_id == -1 )
 328     {
 329         msg_Err( p_stream, "Failed to create poll id for SRT socket." );
 330         goto failed;
 331     }
 332
 333     if ( !srt_schedule_reconnect( p_stream ) )
 334     {
 335         msg_Err( p_stream, "Failed to schedule connect");
 336
 337         goto failed;
 338     }
 339
 340     p_stream->pf_block = BlockSRT;
 341     p_stream->pf_control = Control;
 342
 343     return VLC_SUCCESS;
 344
 345 failed:
 346     vlc_mutex_destroy( &p_sys->lock );
 347
 348     if ( p_sys != NULL )
 349     {
 350         if ( p_sys->sock != -1 ) srt_close( p_sys->sock );
 351         if ( p_sys->i_poll_id != -1 ) srt_epoll_release( p_sys->i_poll_id );
 352
 353         free( p_sys->psz_host );
 354
 355         vlc_obj_free( p_this, p_sys );
 356         p_stream->p_sys = NULL;
 357     }
 358
 359     return VLC_EGENERIC;
 360 }
 361
 362 static void Close(vlc_object_t *p_this)
 363 {
 364     stream_t     *p_stream = (stream_t*)p_this;
 365     stream_sys_t *p_sys = p_stream->p_sys;
 366
 367     if ( p_sys )
 368     {
 369         vlc_mutex_destroy( &p_sys->lock );
 370
 371         srt_epoll_remove_usock( p_sys->i_poll_id, p_sys->sock );
 372         srt_close( p_sys->sock );
 373         srt_epoll_release( p_sys->i_poll_id );
 374
 375         free( p_sys->psz_host );
 376
 377         vlc_obj_free( p_this, p_sys );
 378         p_stream->p_sys = NULL;
 379     }
 380
 381     srt_cleanup();
 382 }
 383
 384 /* Module descriptor */
 385 vlc_module_begin ()
 386     set_shortname( N_("SRT") )
 387     set_description( N_("SRT input") )
 388     set_category( CAT_INPUT )
 389     set_subcategory( SUBCAT_INPUT_ACCESS )
 390
 391     add_integer( "chunk-size", SRT_DEFAULT_CHUNK_SIZE,
 392             N_("SRT chunk size (bytes)"), NULL, true )
 393     add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT,
 394             N_("Return poll wait after timeout milliseconds (-1 = infinite)"), NULL, true )
 395     add_integer( "latency", SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
 396     add_password("passphrase", "", N_("Password for stream encryption"), NULL)
 397     add_integer( "key-length", SRT_DEFAULT_KEY_LENGTH,
 398             SRT_KEY_LENGTH_TEXT, SRT_KEY_LENGTH_TEXT, false )
 399         change_integer_list( srt_key_lengths, srt_key_length_names )
 400
 401     set_capability( "access", 0 )
 402     add_shortcut( "srt" )
 403
 404     set_callbacks( Open, Close )
 405 vlc_module_end ()