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 <limits.h>
  28 #include <errno.h>
  29 #ifdef HAVE_POLL_H
  30 # include <poll.h>
  31 #endif
  32 #ifdef HAVE_SYS_UIO_H
  33 # include <sys/uio.h>
  34 #endif
  35 #ifdef _WIN32
  36 # include <winsock2.h>
  37 #endif
  38
  39 #include <vlc_common.h>
  40 #include <vlc_demux.h>
  41 #include <vlc_block.h>
  42 #include <vlc_dtls.h>
  43
  44 #include "rtp.h"
  45 #ifdef HAVE_SRTP
  46 # include "srtp.h"
  47 #endif
  48
  49 #define DEFAULT_MRU (1500u - (20 + 8))
  50
  51 /**
  52  * Processes a packet received from the RTP socket.
  53  */
  54 static void rtp_process (demux_t *demux, block_t *block)
  55 {
  56     demux_sys_t *sys = demux->p_sys;
  57
  58     if (block->i_buffer < 2)
  59         goto drop;
  60     const uint8_t ptype = rtp_ptype (block);
  61     if (ptype >= 72 && ptype <= 76)
  62         goto drop; /* Muxed RTCP, ignore for now FIXME */
  63
  64 #ifdef HAVE_SRTP
  65     if (sys->srtp != NULL)
  66     {
  67         size_t len = block->i_buffer;
  68         if (srtp_recv (sys->srtp, block->p_buffer, &len))
  69         {
  70             msg_Dbg (demux, "SRTP authentication/decryption failed");
  71             goto drop;
  72         }
  73         block->i_buffer = len;
  74     }
  75 #endif
  76
  77     /* TODO: use SDP and get rid of this hack */
  78     if (unlikely(sys->autodetect))
  79     {   /* Autodetect payload type, _before_ rtp_queue() */
  80         rtp_autodetect (demux, sys->session, block);
  81         sys->autodetect = false;
  82     }
  83
  84     rtp_queue (demux, sys->session, block);
  85     return;
  86 drop:
  87     block_Release (block);
  88 }
  89
  90 static int rtp_timeout (vlc_tick_t deadline)
  91 {
  92     if (deadline == VLC_TICK_INVALID)
  93         return -1; /* infinite */
  94
  95     vlc_tick_t t = vlc_tick_now ();
  96     if (t >= deadline)
  97         return 0;
  98
  99     t = (deadline - t) / (CLOCK_FREQ / INT64_C(1000));
 100     if (unlikely(t > INT_MAX))
 101         return INT_MAX;
 102     return t;
 103 }
 104
 105 /**
 106  * RTP/RTCP session thread for datagram sockets
 107  */
 108 void *rtp_dgram_thread (void *opaque)
 109 {
 110     demux_t *demux = opaque;
 111     demux_sys_t *sys = demux->p_sys;
 112     vlc_tick_t deadline = VLC_TICK_INVALID;
 113     struct vlc_dtls *rtp_sock = sys->rtp_sock;
 114
 115     for (;;)
 116     {
 117         struct pollfd ufd[1];
 118
 119         ufd[0].events = POLLIN;
 120         ufd[0].fd = vlc_dtls_GetPollFD(rtp_sock, &ufd[0].events);
 121
 122         int n = poll (ufd, 1, rtp_timeout (deadline));
 123         if (n == -1)
 124             continue;
 125
 126         int canc = vlc_savecancel ();
 127         if (n == 0)
 128             goto dequeue;
 129
 130         if (ufd[0].revents)
 131         {
 132             block_t *block = block_Alloc(DEFAULT_MRU);
 133             if (unlikely(block == NULL))
 134                 break; /* we are totallly screwed */
 135
 136             bool truncated;
 137             ssize_t len = vlc_dtls_Recv(rtp_sock, block->p_buffer,
 138                                        block->i_buffer, &truncated);
 139             if (len >= 0) {
 140                 if (truncated) {
 141                     msg_Err(demux, "packet truncated (MRU was %zu)",
 142                             block->i_buffer);
 143                     block->i_flags |= BLOCK_FLAG_CORRUPTED;
 144                 }
 145                 else
 146                     block->i_buffer = len;
 147
 148                 rtp_process (demux, block);
 149             }
 150             else
 151             {
 152                 if (errno == EPIPE)
 153                     break; /* connection terminated */
 154                 msg_Warn (demux, "RTP network error: %s",
 155                           vlc_strerror_c(errno));
 156                 block_Release (block);
 157             }
 158
 159             n--;
 160         }
 161
 162     dequeue:
 163         if (!rtp_dequeue (demux, sys->session, &deadline))
 164             deadline = VLC_TICK_INVALID;
 165         vlc_restorecancel (canc);
 166     }
 167     return NULL;
 168 }