modules/stream_out/rtcp.c

   1 /*****************************************************************************
   2  * rtcp.c: RTCP stream output support
   3  *****************************************************************************
   4  * Copyright © 2007 Rémi Denis-Courmont
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *****************************************************************************/
  20
  21 /*****************************************************************************
  22  * Preamble
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <vlc_common.h>
  30 #include <vlc_block.h>
  31
  32 #include <vlc_network.h>
  33 #include <vlc_sout.h>
  34 #include <vlc_fs.h>
  35 #include "rtp.h"
  36
  37 #include <assert.h>
  38
  39 #ifndef SOL_IP
  40 # define SOL_IP IPPROTO_IP
  41 #endif
  42
  43 /*
  44  * NOTE on RTCP implementation:
  45  * - there is a single sender (us), no conferencing here! => n = sender = 1,
  46  * - as such we need not bother to include Receiver Reports,
  47  * - in unicast case, there is a single receiver => members = 1 + 1 = 2,
  48  *   and obviously n > 25% of members,
  49  * - in multicast case, we do not want to maintain the number of receivers
  50  *   and we assume it is big (i.e. than 3) because that's what broadcasting is
  51  *   all about,
  52  * - it is assumed we_sent = true (could be wrong), since we are THE sender,
  53  * - we always send SR + SDES, while running,
  54  * - FIXME: we do not implement separate rate limiting for SDES,
  55  * - we do not implement any profile-specific extensions for the time being.
  56  */
  57 struct rtcp_sender_t
  58 {
  59     size_t   length;  /* RTCP packet length */
  60     uint8_t  payload[28 + 8 + (2 * 257) + 8];
  61     int      handle;  /* RTCP socket handler */
  62
  63     uint32_t packets; /* RTP packets sent */
  64     uint32_t bytes;   /* RTP bytes sent */
  65     unsigned counter; /* RTP packets sent since last RTCP packet */
  66 };
  67
  68
  69 rtcp_sender_t *OpenRTCP (vlc_object_t *obj, int rtp_fd, int proto,
  70                          bool mux)
  71 {
  72     rtcp_sender_t *rtcp;
  73     uint8_t *ptr;
  74     int fd;
  75     char src[NI_MAXNUMERICHOST];
  76     int sport;
  77
  78     if (net_GetSockAddress (rtp_fd, src, &sport))
  79         return NULL;
  80
  81     if (mux)
  82     {
  83         /* RTP/RTCP mux: duplicate the socket */
  84 #ifndef _WIN32
  85         fd = vlc_dup (rtp_fd);
  86 #else
  87         WSAPROTOCOL_INFO info;
  88         WSADuplicateSocket (rtp_fd, GetCurrentProcessId (), &info);
  89         fd = WSASocket (info.iAddressFamily, info.iSocketType, info.iProtocol,
  90                         &info, 0, 0);
  91 #endif
  92     }
  93     else
  94     {
  95         /* RTCP on a separate port */
  96         char dst[NI_MAXNUMERICHOST];
  97         int dport;
  98
  99         if (net_GetPeerAddress (rtp_fd, dst, &dport))
 100             return NULL;
 101
 102         sport++;
 103         dport++;
 104
 105         fd = net_OpenDgram (obj, src, sport, dst, dport, proto);
 106         if (fd != -1)
 107         {
 108             /* Copy the multicast IPv4 TTL value (useless for IPv6) */
 109             int ttl;
 110             socklen_t len = sizeof (ttl);
 111
 112             if (!getsockopt (rtp_fd, SOL_IP, IP_MULTICAST_TTL, &ttl, &len))
 113                 setsockopt (fd, SOL_IP, IP_MULTICAST_TTL, &ttl, len);
 114
 115             /* Ignore all incoming RTCP-RR packets */
 116             setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0 }, sizeof (int));
 117         }
 118     }
 119
 120     if (fd == -1)
 121         return NULL;
 122
 123     rtcp = malloc (sizeof (*rtcp));
 124     if (rtcp == NULL)
 125     {
 126         net_Close (fd);
 127         return NULL;
 128     }
 129
 130     rtcp->handle = fd;
 131     rtcp->bytes = rtcp->packets = rtcp->counter = 0;
 132
 133     ptr = (uint8_t *)strchr (src, '%');
 134     if (ptr != NULL)
 135         *ptr = '\0'; /* remove scope ID frop IPv6 addresses */
 136
 137     ptr = rtcp->payload;
 138
 139     /* Sender report */
 140     ptr[0] = 2 << 6; /* V = 2, P = RC = 0 */
 141     ptr[1] = 200; /* payload type: Sender Report */
 142     SetWBE (ptr + 2, 6); /* length = 6 (7 double words) */
 143     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 144     SetQWBE (ptr + 8, NTPtime64 ());
 145     memset (ptr + 16, 0, 12); /* timestamp and counters */
 146     ptr += 28;
 147
 148     /* Source description */
 149     uint8_t *sdes = ptr;
 150     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 151     ptr[1] = 202; /* payload type: Source Description */
 152     uint8_t *lenptr = ptr + 2;
 153     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 154     ptr += 8;
 155
 156     ptr[0] = 1; /* CNAME - mandatory */
 157     assert (NI_MAXNUMERICHOST <= 256);
 158     ptr[1] = strlen (src);
 159     memcpy (ptr + 2, src, ptr[1]);
 160     ptr += ptr[1] + 2;
 161
 162     static const char tool[] = PACKAGE_STRING;
 163     ptr[0] = 6; /* TOOL */
 164     ptr[1] = (sizeof (tool) > 256) ? 255 : (sizeof (tool) - 1);
 165     memcpy (ptr + 2, tool, ptr[1]);
 166     ptr += ptr[1] + 2;
 167
 168     while ((ptr - sdes) & 3) /* 32-bits padding */
 169         *ptr++ = 0;
 170     SetWBE (lenptr, (ptr - sdes - 1) >> 2);
 171
 172     rtcp->length = ptr - rtcp->payload;
 173     return rtcp;
 174 }
 175
 176
 177 void CloseRTCP (rtcp_sender_t *rtcp)
 178 {
 179     if (rtcp == NULL)
 180         return;
 181
 182     uint8_t *ptr = rtcp->payload;
 183     uint64_t now64 = NTPtime64 ();
 184     SetQWBE (ptr + 8, now64); /* Update the Sender Report timestamp */
 185
 186     /* Bye */
 187     ptr += rtcp->length;
 188     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 189     ptr[1] = 203; /* payload type: Bye */
 190     SetWBE (ptr + 2, 1);
 191     memcpy (ptr + 4, rtcp->payload + 4, 4); /* Copy SSRC from Sender Report */
 192     rtcp->length += 8;
 193
 194     /* We are THE sender, so we are more important than anybody else, so
 195      * we can afford not to check bandwidth constraints here. */
 196     send (rtcp->handle, rtcp->payload, rtcp->length, 0);
 197     net_Close (rtcp->handle);
 198     free (rtcp);
 199 }
 200
 201
 202 void SendRTCP (rtcp_sender_t *restrict rtcp, const block_t *rtp)
 203 {
 204     if ((rtcp == NULL) /* RTCP sender off */
 205      || (rtp->i_buffer < 12)) /* too short RTP packet */
 206         return;
 207
 208     /* Updates statistics */
 209     rtcp->packets++;
 210     rtcp->bytes += rtp->i_buffer;
 211     rtcp->counter += rtp->i_buffer;
 212
 213     /* 1.25% rate limit */
 214     if ((rtcp->counter / 80) < rtcp->length)
 215         return;
 216
 217     uint8_t *ptr = rtcp->payload;
 218     uint32_t last = GetDWBE (ptr + 8); // last RTCP SR send time
 219     uint64_t now64 = NTPtime64 ();
 220     if ((now64 >> 32) < (last + 5))
 221         return; // no more than one SR every 5 seconds
 222
 223     memcpy (ptr + 4, rtp->p_buffer + 8, 4); /* SR SSRC */
 224     SetQWBE (ptr + 8, now64);
 225     memcpy (ptr + 16, rtp->p_buffer + 4, 4); /* RTP timestamp */
 226     SetDWBE (ptr + 20, rtcp->packets);
 227     SetDWBE (ptr + 24, rtcp->bytes);
 228     memcpy (ptr + 28 + 4, rtp->p_buffer + 8, 4); /* SDES SSRC */
 229
 230     if (send (rtcp->handle, ptr, rtcp->length, 0) == (ssize_t)rtcp->length)
 231         rtcp->counter = 0;
 232 }