modules/access/srt.c

   1 /*****************************************************************************
   2  * srt.c: SRT (Secure Reliable Transport) input module
   3  *****************************************************************************
   4  * Copyright (C) 2017, Collabora Ltd.
   5  *
   6  * Authors: Justin Kim <justin.kim@collabora.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include "config.h"
  25 #endif
  26
  27 #include <errno.h>
  28 #include <sys/eventfd.h>
  29 #include <sys/epoll.h>
  30
  31 #include <vlc_common.h>
  32 #include <vlc_interrupt.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_access.h>
  35
  36 #include <vlc_network.h>
  37 #include <vlc_url.h>
  38
  39 #include <srt/srt.h>
  40
  41 /* libsrt defines default packet size as 1316 internally
  42  * so srt module takes same value. */
  43 #define SRT_DEFAULT_CHUNK_SIZE 1316
  44 /* The default timeout is -1 (infinite) */
  45 #define SRT_DEFAULT_POLL_TIMEOUT -1
  46 /* The default latency is 125
  47  * which uses srt library internally */
  48 #define SRT_DEFAULT_LATENCY 125
  49
  50 struct stream_sys_t
  51 {
  52     SRTSOCKET   sock;
  53     int         i_poll_id;
  54     int         i_poll_timeout;
  55     int         i_latency;
  56     size_t      i_chunk_size;
  57     int         i_event_fd;
  58 };
  59
  60 static void srt_wait_interrupted(void *p_data)
  61 {
  62     stream_t *p_stream = p_data;
  63     stream_sys_t *p_sys = p_stream->p_sys;
  64     msg_Dbg( p_stream, "Waking up srt_epoll_wait");
  65     if ( write( p_sys->i_event_fd, &( bool ) { true }, sizeof( bool ) ) < 0 )
  66     {
  67         msg_Err( p_stream, "Failed to send data to event fd");
  68     }
  69 }
  70
  71 static int Control(stream_t *p_stream, int i_query, va_list args)
  72 {
  73     stream_sys_t *p_sys = p_stream->p_sys;
  74     int i_ret = VLC_SUCCESS;
  75
  76     switch( i_query )
  77     {
  78         case STREAM_CAN_SEEK:
  79         case STREAM_CAN_FASTSEEK:
  80         case STREAM_CAN_PAUSE:
  81         case STREAM_CAN_CONTROL_PACE:
  82             *va_arg( args, bool * ) = false;
  83             break;
  84         case STREAM_GET_PTS_DELAY:
  85             *va_arg( args, int64_t * ) = INT64_C(1000)
  86                    * var_InheritInteger(p_stream, "network-caching");
  87             break;
  88         default:
  89             i_ret = VLC_EGENERIC;
  90             break;
  91     }
  92
  93     return i_ret;
  94 }
  95
  96 static block_t *BlockSRT(stream_t *p_stream, bool *restrict eof)
  97 {
  98     stream_sys_t *p_sys = p_stream->p_sys;
  99
 100     block_t *pkt = block_Alloc( p_sys->i_chunk_size );
 101
 102     if ( unlikely( pkt == NULL ) )
 103     {
 104         return NULL;
 105     }
 106
 107     vlc_interrupt_register( srt_wait_interrupted, p_stream);
 108
 109     SRTSOCKET ready[2];
 110     struct epoll_event event[1] = { 0 };
 111
 112     if ( srt_epoll_wait( p_sys->i_poll_id,
 113         ready, &(int) { 2 }, 0, 0, p_sys->i_poll_timeout,
 114         &(int) { p_sys->i_event_fd }, &(int) { 1 }, 0, 0 ) == -1 )
 115     {
 116         int srt_err = srt_getlasterror( NULL );
 117
 118         /* Assuming that timeout error is normal when SRT socket is connected. */
 119         if ( srt_err == SRT_ETIMEOUT && srt_getsockstate( p_sys->sock ) == SRTS_CONNECTED )
 120         {
 121             goto skip;
 122         }
 123
 124         msg_Err( p_stream, "released poll wait (reason : %s)", srt_getlasterror_str() );
 125         goto endofstream;
 126     }
 127
 128     if ( event[0].events & EPOLLIN ) {
 129         bool cancel = 0;
 130         int ret = read( event[0].data.fd, &cancel, sizeof( bool ) );
 131         if ( ret < 0 )
 132         {
 133             goto skip;
 134         }
 135
 136         if ( cancel )
 137         {
 138             msg_Dbg( p_stream, "Cancelled running" );
 139             goto endofstream;
 140         }
 141     }
 142
 143     int stat = srt_recvmsg( p_sys->sock, (char *)pkt->p_buffer, p_sys->i_chunk_size );
 144
 145     if ( stat == SRT_ERROR )
 146     {
 147         msg_Err( p_stream, "failed to recevie SRT packet (reason: %s)", srt_getlasterror_str() );
 148         goto endofstream;
 149     }
 150
 151     pkt->i_buffer = stat;
 152     vlc_interrupt_unregister();
 153     return pkt;
 154
 155 endofstream:
 156     msg_Dbg( p_stream, "EOS");
 157    *eof = true;
 158 skip:
 159     block_Release(pkt);
 160     srt_clearlasterror();
 161     vlc_interrupt_unregister();
 162
 163     return NULL;
 164 }
 165
 166 static int Open(vlc_object_t *p_this)
 167 {
 168     stream_t     *p_stream = (stream_t*)p_this;
 169     stream_sys_t *p_sys = NULL;
 170     vlc_url_t     parsed_url = { 0 };
 171     struct addrinfo hints = {
 172         .ai_socktype = SOCK_DGRAM,
 173     }, *res = NULL;
 174     int stat;
 175
 176     p_sys = vlc_obj_alloc( p_this, 1, sizeof( *p_sys ) );
 177     if( unlikely( p_sys == NULL ) )
 178         return VLC_ENOMEM;
 179
 180     if ( vlc_UrlParse( &parsed_url, p_stream->psz_url ) == -1 )
 181     {
 182         msg_Err( p_stream, "Failed to parse a given URL (%s)", p_stream->psz_url );
 183         goto failed;
 184     }
 185
 186     p_sys->i_chunk_size = var_InheritInteger( p_stream, "chunk-size" );
 187     p_sys->i_poll_timeout = var_InheritInteger( p_stream, "poll-timeout" );
 188     p_sys->i_latency = var_InheritInteger( p_stream, "latency" );
 189     p_sys->i_poll_id = -1;
 190     p_sys->i_event_fd = -1;
 191     p_stream->p_sys = p_sys;
 192     p_stream->pf_block = BlockSRT;
 193     p_stream->pf_control = Control;
 194
 195     stat = vlc_getaddrinfo( parsed_url.psz_host, parsed_url.i_port, &hints, &res );
 196     if ( stat )
 197     {
 198         msg_Err( p_stream, "Cannot resolve [%s]:%d (reason: %s)",
 199                  parsed_url.psz_host,
 200                  parsed_url.i_port,
 201                  gai_strerror( stat ) );
 202
 203         goto failed;
 204     }
 205
 206     p_sys->sock = srt_socket( res->ai_family, SOCK_DGRAM, 0 );
 207     if ( p_sys->sock == SRT_ERROR )
 208     {
 209         msg_Err( p_stream, "Failed to open socket." );
 210         goto failed;
 211     }
 212
 213     /* Make SRT non-blocking */
 214     srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN, &(bool) { false }, sizeof( bool ) );
 215
 216     /* Make sure TSBPD mode is enable (SRT mode) */
 217     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDMODE, &(int) { 1 }, sizeof( int ) );
 218
 219     /* Set latency */
 220     srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDDELAY, &p_sys->i_latency, sizeof( int ) );
 221
 222     p_sys->i_poll_id = srt_epoll_create();
 223     if ( p_sys->i_poll_id == -1 )
 224     {
 225         msg_Err( p_stream, "Failed to create poll id for SRT socket." );
 226         goto failed;
 227     }
 228     srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock, &(int) { SRT_EPOLL_IN } );
 229
 230     p_sys->i_event_fd = eventfd( 0, EFD_NONBLOCK | EFD_CLOEXEC );
 231     srt_epoll_add_ssock( p_sys->i_poll_id, p_sys->i_event_fd, &(int) { EPOLLIN } );
 232
 233     stat = srt_connect( p_sys->sock, res->ai_addr, sizeof (struct sockaddr) );
 234
 235     if ( stat == SRT_ERROR )
 236     {
 237         msg_Err( p_stream, "Failed to connect to server." );
 238         goto failed;
 239     }
 240
 241     vlc_UrlClean( &parsed_url );
 242     freeaddrinfo( res );
 243
 244     return VLC_SUCCESS;
 245
 246 failed:
 247
 248     if ( parsed_url.psz_host != NULL
 249       && parsed_url.psz_buffer != NULL)
 250     {
 251         vlc_UrlClean( &parsed_url );
 252     }
 253
 254     if ( res != NULL )
 255     {
 256         freeaddrinfo( res );
 257     }
 258
 259     if ( p_sys->i_event_fd != -1 )
 260     {
 261         close( p_sys->i_event_fd );
 262         p_sys->i_event_fd = -1;
 263     }
 264
 265     if ( p_sys->i_poll_id != -1 )
 266     {
 267         srt_epoll_release( p_sys->i_poll_id );
 268         p_sys->i_poll_id = -1;
 269     }
 270     srt_close( p_sys->sock );
 271
 272     return VLC_EGENERIC;
 273 }
 274
 275 static void Close(vlc_object_t *p_this)
 276 {
 277     stream_t     *p_stream = (stream_t*)p_this;
 278     stream_sys_t *p_sys = p_stream->p_sys;
 279
 280     if ( p_sys->i_poll_id != -1 )
 281     {
 282         srt_epoll_release( p_sys->i_poll_id );
 283         p_sys->i_poll_id = -1;
 284     }
 285     msg_Dbg( p_stream, "closing server" );
 286     srt_close( p_sys->sock );
 287
 288     if ( p_sys->i_event_fd != -1 )
 289     {
 290         close( p_sys->i_event_fd );
 291         p_sys->i_event_fd = -1;
 292     }
 293 }
 294
 295 /* Module descriptor */
 296 vlc_module_begin ()
 297     set_shortname( N_("SRT") )
 298     set_description( N_("SRT input") )
 299     set_category( CAT_INPUT )
 300     set_subcategory( SUBCAT_INPUT_ACCESS )
 301
 302     add_integer( "chunk-size", SRT_DEFAULT_CHUNK_SIZE,
 303             N_("SRT chunk size (bytes)"), NULL, true )
 304     add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT,
 305             N_("Return poll wait after timeout miliseconds (-1 = infinite)"), NULL, true )
 306     add_integer( "latency", SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
 307
 308     set_capability( "access", 0 )
 309     add_shortcut( "srt" )
 310
 311     set_callbacks( Open, Close )
 312 vlc_module_end ()