modules/access/rtp/input.c

   1 /**
   2  * @file input.c
   3  * @brief RTP packet input
   4  */
   5 /*****************************************************************************
   6  * Copyright © 2008 Rémi Denis-Courmont
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This library 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
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  ****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 #include <vlc_common.h>
  28 #include <vlc_demux.h>
  29 #include <vlc_block.h>
  30 #include <vlc_network.h>
  31
  32 #include <limits.h>
  33 #include <errno.h>
  34 #include <unistd.h>
  35 #ifdef HAVE_POLL
  36 # include <poll.h>
  37 #endif
  38 #ifdef HAVE_SYS_UIO_H
  39 # include <sys/uio.h>
  40 #endif
  41
  42 #include "rtp.h"
  43 #ifdef HAVE_SRTP
  44 # include <srtp.h>
  45 #endif
  46
  47 #define DEFAULT_MRU (1500u - (20 + 8))
  48
  49 /**
  50  * Processes a packet received from the RTP socket.
  51  */
  52 static void rtp_process (demux_t *demux, block_t *block)
  53 {
  54     demux_sys_t *sys = demux->p_sys;
  55
  56     if (block->i_buffer < 2)
  57         goto drop;
  58     const uint8_t ptype = rtp_ptype (block);
  59     if (ptype >= 72 && ptype <= 76)
  60         goto drop; /* Muxed RTCP, ignore for now FIXME */
  61
  62 #ifdef HAVE_SRTP
  63     if (sys->srtp != NULL)
  64     {
  65         size_t len = block->i_buffer;
  66         if (srtp_recv (sys->srtp, block->p_buffer, &len))
  67         {
  68             msg_Dbg (demux, "SRTP authentication/decryption failed");
  69             goto drop;
  70         }
  71         block->i_buffer = len;
  72     }
  73 #endif
  74
  75     /* TODO: use SDP and get rid of this hack */
  76     if (unlikely(sys->autodetect))
  77     {   /* Autodetect payload type, _before_ rtp_queue() */
  78         rtp_autodetect (demux, sys->session, block);
  79         sys->autodetect = false;
  80     }
  81
  82     rtp_queue (demux, sys->session, block);
  83     return;
  84 drop:
  85     block_Release (block);
  86 }
  87
  88 static int rtp_timeout (mtime_t deadline)
  89 {
  90     if (deadline == VLC_TS_INVALID)
  91         return -1; /* infinite */
  92
  93     mtime_t t = mdate ();
  94     if (t >= deadline)
  95         return 0;
  96
  97     t = (deadline - t) / (CLOCK_FREQ / INT64_C(1000));
  98     if (unlikely(t > INT_MAX))
  99         return INT_MAX;
 100     return t;
 101 }
 102
 103 /**
 104  * RTP/RTCP session thread for datagram sockets
 105  */
 106 void *rtp_dgram_thread (void *opaque)
 107 {
 108     demux_t *demux = opaque;
 109     demux_sys_t *sys = demux->p_sys;
 110     mtime_t deadline = VLC_TS_INVALID;
 111     int rtp_fd = sys->fd;
 112     struct iovec iov =
 113     {
 114         .iov_len = DEFAULT_MRU,
 115     };
 116     struct msghdr msg =
 117     {
 118         .msg_iov = &iov,
 119         .msg_iovlen = 1,
 120     };
 121
 122     struct pollfd ufd[1];
 123     ufd[0].fd = rtp_fd;
 124     ufd[0].events = POLLIN;
 125
 126     for (;;)
 127     {
 128         int n = poll (ufd, 1, rtp_timeout (deadline));
 129         if (n == -1)
 130             continue;
 131
 132         int canc = vlc_savecancel ();
 133         if (n == 0)
 134             goto dequeue;
 135
 136         if (ufd[0].revents)
 137         {
 138             n--;
 139             if (unlikely(ufd[0].revents & POLLHUP))
 140                 break; /* RTP socket dead (DCCP only) */
 141
 142             block_t *block = block_Alloc (iov.iov_len);
 143             if (unlikely(block == NULL))
 144             {
 145                 if (iov.iov_len == DEFAULT_MRU)
 146                     break; /* we are totallly screwed */
 147                 iov.iov_len = DEFAULT_MRU;
 148                 continue; /* retry with shrunk MRU */
 149             }
 150
 151             iov.iov_base = block->p_buffer;
 152 #ifdef __linux__
 153             msg.msg_flags = MSG_TRUNC;
 154 #else
 155             msg.msg_flags = 0;
 156 #endif
 157
 158             ssize_t len = recvmsg (rtp_fd, &msg, 0);
 159             if (len != -1)
 160             {
 161 #ifdef MSG_TRUNC
 162                 if (msg.msg_flags & MSG_TRUNC)
 163                 {
 164                     msg_Err(demux, "%zd bytes packet truncated (MRU was %zu)",
 165                             len, iov.iov_len);
 166                     block->i_flags |= BLOCK_FLAG_CORRUPTED;
 167                     iov.iov_len = len;
 168                 }
 169                 else
 170 #endif
 171                     block->i_buffer = len;
 172
 173                 rtp_process (demux, block);
 174             }
 175             else
 176             {
 177                 msg_Warn (demux, "RTP network error: %s",
 178                           vlc_strerror_c(errno));
 179                 block_Release (block);
 180             }
 181         }
 182
 183     dequeue:
 184         if (!rtp_dequeue (demux, sys->session, &deadline))
 185             deadline = VLC_TS_INVALID;
 186         vlc_restorecancel (canc);
 187     }
 188     return NULL;
 189 }
 190
 191 /**
 192  * RTP/RTCP session thread for stream sockets (framed RTP)
 193  */
 194 void *rtp_stream_thread (void *opaque)
 195 {
 196 #ifndef _WIN32
 197     demux_t *demux = opaque;
 198     demux_sys_t *sys = demux->p_sys;
 199     int fd = sys->fd;
 200
 201     for (;;)
 202     {
 203         /* There is no reordering on stream sockets, so no timeout. */
 204         ssize_t val;
 205
 206         uint16_t frame_len;
 207         if (recv (fd, &frame_len, 2, MSG_WAITALL) != 2)
 208             break;
 209
 210         block_t *block = block_Alloc (ntohs (frame_len));
 211         if (unlikely(block == NULL))
 212             break;
 213
 214         block_cleanup_push (block);
 215         val = recv (fd, block->p_buffer, block->i_buffer, MSG_WAITALL);
 216         vlc_cleanup_pop ();
 217
 218         if (val != (ssize_t)block->i_buffer)
 219         {
 220             block_Release (block);
 221             break;
 222         }
 223
 224         int canc = vlc_savecancel ();
 225         rtp_process (demux, block);
 226         rtp_dequeue_force (demux, sys->session);
 227         vlc_restorecancel (canc);
 228     }
 229 #else
 230     (void) opaque;
 231 #endif
 232     return NULL;
 233 }