modules/stream_out/rtcp.c

   1 /*****************************************************************************
   2  * rtcp.c: RTCP stream output support
   3  *****************************************************************************
   4  * Copyright © 2007 Rémi Denis-Courmont
   5  * $Id$
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20  *****************************************************************************/
  21
  22 /*****************************************************************************
  23  * Preamble
  24  *****************************************************************************/
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <vlc_common.h>
  31 #include <vlc_block.h>
  32
  33 #include <vlc_network.h>
  34 #include <vlc_sout.h>
  35 #include <vlc_fs.h>
  36 #include "rtp.h"
  37
  38 #include <assert.h>
  39
  40 #ifndef SOL_IP
  41 # define SOL_IP IPPROTO_IP
  42 #endif
  43
  44 /*
  45  * NOTE on RTCP implementation:
  46  * - there is a single sender (us), no conferencing here! => n = sender = 1,
  47  * - as such we need not bother to include Receiver Reports,
  48  * - in unicast case, there is a single receiver => members = 1 + 1 = 2,
  49  *   and obviously n > 25% of members,
  50  * - in multicast case, we do not want to maintain the number of receivers
  51  *   and we assume it is big (i.e. than 3) because that's what broadcasting is
  52  *   all about,
  53  * - it is assumed we_sent = true (could be wrong), since we are THE sender,
  54  * - we always send SR + SDES, while running,
  55  * - FIXME: we do not implement separate rate limiting for SDES,
  56  * - we do not implement any profile-specific extensions for the time being.
  57  */
  58 struct rtcp_sender_t
  59 {
  60     size_t   length;  /* RTCP packet length */
  61     uint8_t  payload[28 + 8 + (2 * 257) + 8];
  62     int      handle;  /* RTCP socket handler */
  63
  64     uint32_t packets; /* RTP packets sent */
  65     uint32_t bytes;   /* RTP bytes sent */
  66     unsigned counter; /* RTP packets sent since last RTCP packet */
  67 };
  68
  69
  70 rtcp_sender_t *OpenRTCP (vlc_object_t *obj, int rtp_fd, int proto,
  71                          bool mux)
  72 {
  73     rtcp_sender_t *rtcp;
  74     uint8_t *ptr;
  75     int fd;
  76     char src[NI_MAXNUMERICHOST];
  77     int sport;
  78
  79     if (net_GetSockAddress (rtp_fd, src, &sport))
  80         return NULL;
  81
  82     if (mux)
  83     {
  84         /* RTP/RTCP mux: duplicate the socket */
  85 #ifndef WIN32
  86         fd = vlc_dup (rtp_fd);
  87 #elif defined(UNDER_CE)
  88  #warning Muxed RTP/RTCP unimplemented!
  89         fd = -1;
  90 #else
  91         WSAPROTOCOL_INFO info;
  92         WSADuplicateSocket (rtp_fd, GetCurrentProcessId (), &info);
  93         fd = WSASocket (info.iAddressFamily, info.iSocketType, info.iProtocol,
  94                         &info, 0, 0);
  95 #endif
  96     }
  97     else
  98     {
  99         /* RTCP on a separate port */
 100         char dst[NI_MAXNUMERICHOST];
 101         int dport;
 102
 103         if (net_GetPeerAddress (rtp_fd, dst, &dport))
 104             return NULL;
 105
 106         sport++;
 107         dport++;
 108
 109         fd = net_OpenDgram (obj, src, sport, dst, dport, AF_UNSPEC, proto);
 110         if (fd != -1)
 111         {
 112             /* Copy the multicast IPv4 TTL value (useless for IPv6) */
 113             int ttl;
 114             socklen_t len = sizeof (ttl);
 115
 116             if (!getsockopt (rtp_fd, SOL_IP, IP_MULTICAST_TTL, &ttl, &len))
 117                 setsockopt (fd, SOL_IP, IP_MULTICAST_TTL, &ttl, len);
 118
 119             /* Ignore all incoming RTCP-RR packets */
 120             setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0 }, sizeof (int));
 121         }
 122     }
 123
 124     if (fd == -1)
 125         return NULL;
 126
 127     rtcp = malloc (sizeof (*rtcp));
 128     if (rtcp == NULL)
 129     {
 130         net_Close (fd);
 131         return NULL;
 132     }
 133
 134     rtcp->handle = fd;
 135     rtcp->bytes = rtcp->packets = rtcp->counter = 0;
 136
 137     ptr = (uint8_t *)strchr (src, '%');
 138     if (ptr != NULL)
 139         *ptr = '\0'; /* remove scope ID frop IPv6 addresses */
 140
 141     ptr = rtcp->payload;
 142
 143     /* Sender report */
 144     ptr[0] = 2 << 6; /* V = 2, P = RC = 0 */
 145     ptr[1] = 200; /* payload type: Sender Report */
 146     SetWBE (ptr + 2, 6); /* length = 6 (7 double words) */
 147     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 148     SetQWBE (ptr + 8, NTPtime64 ());
 149     memset (ptr + 16, 0, 12); /* timestamp and counters */
 150     ptr += 28;
 151
 152     /* Source description */
 153     uint8_t *sdes = ptr;
 154     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 155     ptr[1] = 202; /* payload type: Source Description */
 156     uint8_t *lenptr = ptr + 2;
 157     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 158     ptr += 8;
 159
 160     ptr[0] = 1; /* CNAME - mandatory */
 161     assert (NI_MAXNUMERICHOST <= 256);
 162     ptr[1] = strlen (src);
 163     memcpy (ptr + 2, src, ptr[1]);
 164     ptr += ptr[1] + 2;
 165
 166     static const char tool[] = PACKAGE_STRING;
 167     ptr[0] = 6; /* TOOL */
 168     ptr[1] = (sizeof (tool) > 256) ? 255 : (sizeof (tool) - 1);
 169     memcpy (ptr + 2, tool, ptr[1]);
 170     ptr += ptr[1] + 2;
 171
 172     while ((ptr - sdes) & 3) /* 32-bits padding */
 173         *ptr++ = 0;
 174     SetWBE (lenptr, (ptr - sdes - 1) >> 2);
 175
 176     rtcp->length = ptr - rtcp->payload;
 177     return rtcp;
 178 }
 179
 180
 181 void CloseRTCP (rtcp_sender_t *rtcp)
 182 {
 183     if (rtcp == NULL)
 184         return;
 185
 186     uint8_t *ptr = rtcp->payload;
 187     uint64_t now64 = NTPtime64 ();
 188     SetQWBE (ptr + 8, now64); /* Update the Sender Report timestamp */
 189
 190     /* Bye */
 191     ptr += rtcp->length;
 192     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 193     ptr[1] = 203; /* payload type: Bye */
 194     SetWBE (ptr + 2, 1);
 195     memcpy (ptr + 4, rtcp->payload + 4, 4); /* Copy SSRC from Sender Report */
 196     rtcp->length += 8;
 197
 198     /* We are THE sender, so we are more important than anybody else, so
 199      * we can afford not to check bandwidth constraints here. */
 200     send (rtcp->handle, rtcp->payload, rtcp->length, 0);
 201     net_Close (rtcp->handle);
 202     free (rtcp);
 203 }
 204
 205
 206 void SendRTCP (rtcp_sender_t *restrict rtcp, const block_t *rtp)
 207 {
 208     if ((rtcp == NULL) /* RTCP sender off */
 209      || (rtp->i_buffer < 12)) /* too short RTP packet */
 210         return;
 211
 212     /* Updates statistics */
 213     rtcp->packets++;
 214     rtcp->bytes += rtp->i_buffer;
 215     rtcp->counter += rtp->i_buffer;
 216
 217     /* 1.25% rate limit */
 218     if ((rtcp->counter / 80) < rtcp->length)
 219         return;
 220
 221     uint8_t *ptr = rtcp->payload;
 222     uint32_t last = GetDWBE (ptr + 8); // last RTCP SR send time
 223     uint64_t now64 = NTPtime64 ();
 224     if ((now64 >> 32) < (last + 5))
 225         return; // no more than one SR every 5 seconds
 226
 227     memcpy (ptr + 4, rtp->p_buffer + 8, 4); /* SR SSRC */
 228     SetQWBE (ptr + 8, now64);
 229     memcpy (ptr + 16, rtp->p_buffer + 4, 4); /* RTP timestamp */
 230     SetDWBE (ptr + 20, rtcp->packets);
 231     SetDWBE (ptr + 24, rtcp->bytes);
 232     memcpy (ptr + 28 + 4, rtp->p_buffer + 8, 4); /* SDES SSRC */
 233
 234     if (send (rtcp->handle, ptr, rtcp->length, 0) == (ssize_t)rtcp->length)
 235         rtcp->counter = 0;
 236 }