src/mops_ext_rtp.c

   1 /*
   2  * Mausezahn - A fast versatile traffic generator
   3  * Copyright (C) 2008-2010 Herbert Haas
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License version 2 as published by the
   7  * Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
  12  * details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, see http://www.gnu.org/licenses/gpl-2.0.html
  16  *
  17 */
  18
  19 #include "mz.h"
  20 #include "mops.h"
  21 #include "cli.h"
  22
  23
  24
  25 // Initialization function - specify defaults here!
  26 //
  27 int mops_init_pdesc_rtp(struct mops *mp)
  28 {
  29         struct mops_ext_rtp * pd;
  30
  31         if (mp->p_desc == NULL) return 1;  // p_desc not properly assigned
  32         pd = mp->p_desc;
  33
  34         // set RTP defaults
  35         pd->v           = 2;
  36         pd->p           = 0;
  37         pd->x           = 0;
  38         pd->cc          = 0;
  39         pd->m           = 0;
  40
  41         pd->pt            = 8; // 0=PCMU, 8=PCMA
  42         pd->sqnr          = 0;
  43         pd->tst           = 0;
  44         pd->tst_inc       = 160;
  45         pd->ssrc          = mz_rand32(); // Default Mausezahn stream would be 0xCAFEBABE
  46         pd->source        = 0; // don't use /dev/dsp  (but user may configure source = DSP_SOURCE)
  47         pd->cc_real       = 0;
  48
  49         pd->x_type = 0; // no extension by default
  50
  51         // General packet parameters
  52         mp->dp = 30000;
  53         mp->sp = 30002;
  54         mp->ndelay.tv_sec = 0;
  55         mp->ndelay.tv_nsec = 20000000;
  56
  57         memset(&pd->payload, 0x00, MOPS_RTP_MAX_PAYLOAD_SIZE);
  58
  59         return 0;
  60 }
  61
  62
  63 /*
  64  *  Standard RTP header according RFC 3550
  65  *
  66  *     0                   1                   2                   3
  67  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  68  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  69  *    |V=2|P|X|  CC   |M|     PT      |       sequence number         |
  70  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  71  *    |                           timestamp                           |
  72  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  73  *    |           synchronization source (SSRC) identifier            |
  74  *    +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
  75  *    |            contributing source (CSRC) identifiers             |
  76  *    |                             ....                              |
  77  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  78  *
  79  *  !!! NOTE !!! -- This function should be used only to prepare the RTP
  80  *  header once. It does not update dynamic fields. To update dynamic fields
  81  *  each time a subsequent RTP packet is sent, use the function
  82  *  mops_update_rtp_dynamics().
  83  *
  84  */
  85 int mops_update_rtp (struct mops * mp)
  86 {
  87         struct mops_ext_rtp * pd;
  88         int i,j;
  89
  90         pd = mp->p_desc;
  91         if (pd==NULL) return 1;  // no valid pointer to a p_desc
  92         mp->msg_s = 0;           // !! IMPORTANT !! Otherwise the msg would get longer and longer after each call!
  93
  94         // 1st byte
  95         mops_msg_add_byte (mp, pd->cc);
  96         mops_msg_add_field (mp, pd->v, 6);
  97         mops_msg_add_field (mp, pd->p, 5);
  98         mops_msg_add_field (mp, pd->x, 4);
  99
 100         // 2nd byte
 101         mops_msg_add_byte (mp, pd->pt);
 102         mops_msg_add_field (mp, pd->m, 7);
 103
 104         // remaining
 105         mops_msg_add_2bytes (mp, pd->sqnr);
 106         mops_msg_add_4bytes (mp, pd->tst);
 107         mops_msg_add_4bytes (mp, pd->ssrc);
 108
 109         // Add CSRC list?
 110         if ((j=pd->cc_real)) {
 111                 if (j>16) { j=16; pd->cc_real=16; } // silent self healing if desired :-)
 112                 for (i=0; i<j; i++)
 113                         mops_msg_add_4bytes (mp, pd->csrc[i]);
 114         }
 115         pd->rtp_header_len = 12 + j*4;
 116
 117         /*
 118          *  Add Extension header?
 119          *
 120          *     0                   1                   2                   3
 121          *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 122          *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 123          *    |      defined by profile       |           length              |
 124          *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 125          *    |                        header extension                       |
 126          *    |                             ....                              |
 127          */
 128
 129         switch (pd->x_type) {
 130          case 0: // none
 131                 break;
 132          case 1: // set aero, 8 bytes in total -- TODO --
 133                 break;
 134          case 42: // Mausezahn extension header:
 135                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 136                   //    |      MOPS_RTP_EXT_MZID        |           length=4            |
 137                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 138                   //    |                      TX-timestamp sec                         |
 139                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 140                   //    |                      TX-timestamp nsec                        |
 141                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 142                   //    |                 Estimated Peer TX-timestamp sec               |
 143                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 144                   //    |                 Estimated Peer TX-timestamp nsec              |
 145                   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 146
 147                 mops_msg_add_2bytes (mp, MOPS_RTP_EXT_MZID);
 148                 mops_msg_add_2bytes (mp, 2);
 149                 mops_msg_add_4bytes (mp, 0); // only placeholders, must be updated each packet
 150                 mops_msg_add_4bytes (mp, 0); // only placeholders, must be updated each packet
 151                 mops_msg_add_4bytes (mp, 0); // only placeholders, must be updated each packet
 152                 mops_msg_add_4bytes (mp, 0); // only placeholders, must be updated each packet
 153
 154                 pd->rtp_header_len += 20;
 155                 break;
 156          default:
 157                 return 1;
 158                 break; // paranoid?
 159         }
 160
 161         // Now add the payload
 162         switch (pd->pt) {
 163          case 0:
 164          case 8:
 165                 mp->msg_s = 160 + pd->rtp_header_len; // simply set total RTP PDU length (the RTP payload is still undefined)
 166                 mp->ndelay.tv_sec = 0;
 167                 mp->ndelay.tv_nsec = 20000000;
 168                 break;
 169          default:
 170                 break;
 171         }
 172
 173         return 0;
 174 }
 175
 176
 177
 178 // This function directly updates the dynamic RTP fields
 179 // within the mops frame (=be quick here).
 180 //
 181 // This function is typically called from within the transmission loops,
 182 // see e. g. mops_tx_thread_native()
 183 //
 184 // This includes:
 185 //
 186 //   - RTP SQNR
 187 //   - RTP Timestamp
 188 //   - Mausezahn extension header if any
 189 //   - The RTP payload
 190 //
 191 int mops_update_rtp_dynamics (struct mops * mp)
 192 {
 193         struct mops_ext_rtp * pd;
 194         struct timespec ct;
 195         int j, i = mp->begin_MSG;
 196
 197         pd = mp->p_desc;  if (pd==NULL) return 1;
 198
 199
 200         // The following variables must be incremented AFTER assignment to frame,
 201         // so the initial values are also used!
 202         //
 203         mops_hton2 (&pd->sqnr, &mp->frame[i+2]);
 204         pd->sqnr++;
 205
 206         mops_hton4 (&pd->tst, &mp->frame[i+4]);
 207         pd->tst += pd->tst_inc;
 208
 209
 210         // Extension header:
 211         // Timestamp must be updated BEFORE assignment to frame
 212         //
 213         switch (pd->x_type) {
 214          case 42: // Mausezahn extension header: Update timestamps
 215                 j = i + pd->rtp_header_len; // points to first byte of timestamp of MZ extension header
 216                 clock_gettime(CLOCK_MONOTONIC, &ct);
 217                 mops_hton4 ((u_int32_t*) &ct.tv_sec,  &mp->frame[j-16]);
 218                 mops_hton4 ((u_int32_t*) &ct.tv_nsec, &mp->frame[j-12]);
 219 //[TODO] **** estimated peer timestamp **** PSEUDOCODE FOLLOWING:
 220 //              if (peer_exists) {
 221 //                 get_peer_timestamp_estimation(&est);
 222 //                 mops_hton4 ((u_int32_t*) &est.sec,  &mp->frame[j-8]);
 223 //                 mops_hton4 ((u_int32_t*) &est.nsec, &mp->frame[j-4]);
 224 //              }
 225                 break;
 226          default:
 227                 return 0;
 228                 break;
 229         }
 230
 231         // The pd->payload contains either zeroes or realtime voice data
 232         //   The pd->payload is initialized with zeroes and IFF a reading thread
 233         //   exists, it may copy voice segments (e. g. from /dev/dsp) to
 234         //   pd->payload.
 235         // NOTE that there is NO NEED to protect pd->payload with mutexes, because
 236         // only if the reading thread is finished it (itself!) will call THIS function.
 237         if (pd->source == DSP_SOURCE) {
 238                 memcpy((void*) &mp->frame[j], (void*) pd->payload, pd->payload_s);
 239         }
 240
 241         return 0;
 242 }
 243