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 #else
  88         WSAPROTOCOL_INFO info;
  89         WSADuplicateSocket (rtp_fd, GetCurrentProcessId (), &info);
  90         fd = WSASocket (info.iAddressFamily, info.iSocketType, info.iProtocol,
  91                         &info, 0, 0);
  92 #endif
  93     }
  94     else
  95     {
  96         /* RTCP on a separate port */
  97         char dst[NI_MAXNUMERICHOST];
  98         int dport;
  99
 100         if (net_GetPeerAddress (rtp_fd, dst, &dport))
 101             return NULL;
 102
 103         sport++;
 104         dport++;
 105
 106         fd = net_OpenDgram (obj, src, sport, dst, dport, proto);
 107         if (fd != -1)
 108         {
 109             /* Copy the multicast IPv4 TTL value (useless for IPv6) */
 110             int ttl;
 111             socklen_t len = sizeof (ttl);
 112
 113             if (!getsockopt (rtp_fd, SOL_IP, IP_MULTICAST_TTL, &ttl, &len))
 114                 setsockopt (fd, SOL_IP, IP_MULTICAST_TTL, &ttl, len);
 115
 116             /* Ignore all incoming RTCP-RR packets */
 117             setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0 }, sizeof (int));
 118         }
 119     }
 120
 121     if (fd == -1)
 122         return NULL;
 123
 124     rtcp = malloc (sizeof (*rtcp));
 125     if (rtcp == NULL)
 126     {
 127         net_Close (fd);
 128         return NULL;
 129     }
 130
 131     rtcp->handle = fd;
 132     rtcp->bytes = rtcp->packets = rtcp->counter = 0;
 133
 134     ptr = (uint8_t *)strchr (src, '%');
 135     if (ptr != NULL)
 136         *ptr = '\0'; /* remove scope ID frop IPv6 addresses */
 137
 138     ptr = rtcp->payload;
 139
 140     /* Sender report */
 141     ptr[0] = 2 << 6; /* V = 2, P = RC = 0 */
 142     ptr[1] = 200; /* payload type: Sender Report */
 143     SetWBE (ptr + 2, 6); /* length = 6 (7 double words) */
 144     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 145     SetQWBE (ptr + 8, NTPtime64 ());
 146     memset (ptr + 16, 0, 12); /* timestamp and counters */
 147     ptr += 28;
 148
 149     /* Source description */
 150     uint8_t *sdes = ptr;
 151     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 152     ptr[1] = 202; /* payload type: Source Description */
 153     uint8_t *lenptr = ptr + 2;
 154     memset (ptr + 4, 0, 4); /* SSRC unknown yet */
 155     ptr += 8;
 156
 157     ptr[0] = 1; /* CNAME - mandatory */
 158     assert (NI_MAXNUMERICHOST <= 256);
 159     ptr[1] = strlen (src);
 160     memcpy (ptr + 2, src, ptr[1]);
 161     ptr += ptr[1] + 2;
 162
 163     static const char tool[] = PACKAGE_STRING;
 164     ptr[0] = 6; /* TOOL */
 165     ptr[1] = (sizeof (tool) > 256) ? 255 : (sizeof (tool) - 1);
 166     memcpy (ptr + 2, tool, ptr[1]);
 167     ptr += ptr[1] + 2;
 168
 169     while ((ptr - sdes) & 3) /* 32-bits padding */
 170         *ptr++ = 0;
 171     SetWBE (lenptr, (ptr - sdes - 1) >> 2);
 172
 173     rtcp->length = ptr - rtcp->payload;
 174     return rtcp;
 175 }
 176
 177
 178 void CloseRTCP (rtcp_sender_t *rtcp)
 179 {
 180     if (rtcp == NULL)
 181         return;
 182
 183     uint8_t *ptr = rtcp->payload;
 184     uint64_t now64 = NTPtime64 ();
 185     SetQWBE (ptr + 8, now64); /* Update the Sender Report timestamp */
 186
 187     /* Bye */
 188     ptr += rtcp->length;
 189     ptr[0] = (2 << 6) | 1; /* V = 2, P = 0, SC = 1 */
 190     ptr[1] = 203; /* payload type: Bye */
 191     SetWBE (ptr + 2, 1);
 192     memcpy (ptr + 4, rtcp->payload + 4, 4); /* Copy SSRC from Sender Report */
 193     rtcp->length += 8;
 194
 195     /* We are THE sender, so we are more important than anybody else, so
 196      * we can afford not to check bandwidth constraints here. */
 197     send (rtcp->handle, rtcp->payload, rtcp->length, 0);
 198     net_Close (rtcp->handle);
 199     free (rtcp);
 200 }
 201
 202
 203 void SendRTCP (rtcp_sender_t *restrict rtcp, const block_t *rtp)
 204 {
 205     if ((rtcp == NULL) /* RTCP sender off */
 206      || (rtp->i_buffer < 12)) /* too short RTP packet */
 207         return;
 208
 209     /* Updates statistics */
 210     rtcp->packets++;
 211     rtcp->bytes += rtp->i_buffer;
 212     rtcp->counter += rtp->i_buffer;
 213
 214     /* 1.25% rate limit */
 215     if ((rtcp->counter / 80) < rtcp->length)
 216         return;
 217
 218     uint8_t *ptr = rtcp->payload;
 219     uint32_t last = GetDWBE (ptr + 8); // last RTCP SR send time
 220     uint64_t now64 = NTPtime64 ();
 221     if ((now64 >> 32) < (last + 5))
 222         return; // no more than one SR every 5 seconds
 223
 224     memcpy (ptr + 4, rtp->p_buffer + 8, 4); /* SR SSRC */
 225     SetQWBE (ptr + 8, now64);
 226     memcpy (ptr + 16, rtp->p_buffer + 4, 4); /* RTP timestamp */
 227     SetDWBE (ptr + 20, rtcp->packets);
 228     SetDWBE (ptr + 24, rtcp->bytes);
 229     memcpy (ptr + 28 + 4, rtp->p_buffer + 8, 4); /* SDES SSRC */
 230
 231     if (send (rtcp->handle, ptr, rtcp->length, 0) == (ssize_t)rtcp->length)
 232         rtcp->counter = 0;
 233 }