stream/rtp.c

   1 /* Imported from the dvbstream-0.2 project
   2  *
   3  * Modified for use with MPlayer, for details see the changelog at
   4  * http://svn.mplayerhq.hu/mplayer/trunk/
   5  * $Id$
   6  */
   7
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <stdlib.h>
  12 #include <stdio.h>
  13 #include <sys/types.h>
  14 #include <ctype.h>
  15 #include "config.h"
  16 #ifndef HAVE_WINSOCK2
  17 #include <netinet/in.h>
  18 #include <sys/socket.h>
  19 #include <arpa/inet.h>
  20 #define closesocket close
  21 #else
  22 #include <winsock2.h>
  23 #include <ws2tcpip.h>
  24 #endif
  25 #include <errno.h>
  26 #include "stream.h"
  27
  28 /* MPEG-2 TS RTP stack */
  29
  30 #define DEBUG        1
  31 #include "mp_msg.h"
  32 #include "rtp.h"
  33
  34 // RTP reorder routines
  35 // Also handling of repeated UDP packets (a bug of ExtremeNetworks switches firmware)
  36 // rtpreord procedures
  37 // write rtp packets in cache
  38 // get rtp packets reordered
  39
  40 #define MAXRTPPACKETSIN 32   // The number of max packets being reordered
  41
  42 struct rtpbits {
  43   unsigned int v:2;           /* version: 2 */
  44   unsigned int p:1;           /* is there padding appended: 0 */
  45   unsigned int x:1;           /* number of extension headers: 0 */
  46   unsigned int cc:4;          /* number of CSRC identifiers: 0 */
  47   unsigned int m:1;           /* marker: 0 */
  48   unsigned int pt:7;          /* payload type: 33 for MPEG2 TS - RFC 1890 */
  49   unsigned int sequence:16;   /* sequence number: random */
  50 };
  51
  52 struct rtpheader {      /* in network byte order */
  53   struct rtpbits b;
  54   int timestamp;        /* start: random */
  55   int ssrc;             /* random */
  56 };
  57
  58 struct rtpbuffer
  59 {
  60         unsigned char  data[MAXRTPPACKETSIN][STREAM_BUFFER_SIZE];
  61         unsigned short  seq[MAXRTPPACKETSIN];
  62         unsigned short  len[MAXRTPPACKETSIN];
  63         unsigned short first;
  64 };
  65 static struct rtpbuffer rtpbuf;
  66
  67 static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData);
  68
  69 // RTP Reordering functions
  70 // Algorithm works as follows:
  71 // If next packet is in sequence just copy it to buffer
  72 // Otherwise copy it in cache according to its sequence number
  73 // Cache is a circular array where "rtpbuf.first" points to next sequence slot
  74 // and keeps track of expected sequence
  75
  76 // Initialize rtp cache
  77 static void rtp_cache_reset(unsigned short seq)
  78 {
  79         int i;
  80
  81         rtpbuf.first = 0;
  82         rtpbuf.seq[0] = ++seq;
  83
  84         for (i=0; i<MAXRTPPACKETSIN; i++) {
  85                 rtpbuf.len[i] = 0;
  86         }
  87 }
  88
  89 // Write in a cache the rtp packet in right rtp sequence order
  90 static int rtp_cache(int fd, char *buffer, int length)
  91 {
  92         struct rtpheader rh;
  93         int newseq;
  94         char *data;
  95         unsigned short seq;
  96         static int is_first = 1;
  97
  98         getrtp2(fd, &rh, &data, &length);
  99         if(!length)
 100                 return 0;
 101         seq = rh.b.sequence;
 102
 103         newseq = seq - rtpbuf.seq[rtpbuf.first];
 104
 105         if ((newseq == 0) || is_first)
 106         {
 107                 is_first = 0;
 108
 109                 //mp_msg(MSGT_NETWORK, MSGL_DBG4, "RTP (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
 110                 rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
 111                 rtpbuf.seq[rtpbuf.first] = ++seq;
 112                 goto feed;
 113         }
 114
 115         if (newseq > MAXRTPPACKETSIN)
 116         {
 117                 mp_msg(MSGT_NETWORK, MSGL_DBG2, "Overrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
 118                 rtp_cache_reset(seq);
 119                 goto feed;
 120         }
 121
 122         if (newseq < 0)
 123         {
 124                 int i;
 125
 126                 // Is it a stray packet re-sent to network?
 127                 for (i=0; i<MAXRTPPACKETSIN; i++) {
 128                         if (rtpbuf.seq[i] == seq) {
 129                                 mp_msg(MSGT_NETWORK, MSGL_ERR, "Stray packet (seq[%d]=%d seq=%d, newseq=%d found at %d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq, i);
 130                                 return  0; // Yes, it is!
 131                         }
 132                 }
 133                 // Some heuristic to decide when to drop packet or to restart everything
 134                 if (newseq > -(3 * MAXRTPPACKETSIN)) {
 135                         mp_msg(MSGT_NETWORK, MSGL_ERR, "Too Old packet (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
 136                         return  0; // Yes, it is!
 137                 }
 138
 139                 mp_msg(MSGT_NETWORK, MSGL_ERR,  "Underrun(seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
 140
 141                 rtp_cache_reset(seq);
 142                 goto feed;
 143         }
 144
 145         mp_msg(MSGT_NETWORK, MSGL_DBG4, "Out of Seq (seq[%d]=%d seq=%d, newseq=%d)\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first], seq, newseq);
 146         newseq = ( newseq + rtpbuf.first ) % MAXRTPPACKETSIN;
 147         memcpy (rtpbuf.data[newseq], data, length);
 148         rtpbuf.len[newseq] = length;
 149         rtpbuf.seq[newseq] = seq;
 150
 151         return 0;
 152
 153 feed:
 154         memcpy (buffer, data, length);
 155         return length;
 156 }
 157
 158 // Get next packet in cache
 159 // Look in cache to get first packet in sequence
 160 static int rtp_get_next(int fd, char *buffer, int length)
 161 {
 162         int i;
 163         unsigned short nextseq;
 164
 165         // If we have empty buffer we loop to fill it
 166         for (i=0; i < MAXRTPPACKETSIN -3; i++) {
 167                 if (rtpbuf.len[rtpbuf.first] != 0) break;
 168
 169                 length = rtp_cache(fd, buffer, length) ;
 170
 171                 // returns on first packet in sequence
 172                 if (length > 0) {
 173                         //mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp [%d] %hu\n", i, rtpbuf.first);
 174                         return length;
 175                 } else if (length < 0) break;
 176
 177                 // Only if length == 0 loop continues!
 178         }
 179
 180         i = rtpbuf.first;
 181         while (rtpbuf.len[i] == 0) {
 182                 mp_msg(MSGT_NETWORK, MSGL_ERR,  "Lost packet %hu\n", rtpbuf.seq[i]);
 183                 i = ( 1 + i ) % MAXRTPPACKETSIN;
 184                 if (rtpbuf.first == i) break;
 185         }
 186         rtpbuf.first = i;
 187
 188         // Copy next non empty packet from cache
 189         mp_msg(MSGT_NETWORK, MSGL_DBG4, "Getting rtp from cache [%d] %hu\n", rtpbuf.first, rtpbuf.seq[rtpbuf.first]);
 190         memcpy (buffer, rtpbuf.data[rtpbuf.first], rtpbuf.len[rtpbuf.first]);
 191         length = rtpbuf.len[rtpbuf.first]; // can be zero?
 192
 193         // Reset fisrt slot and go next in cache
 194         rtpbuf.len[rtpbuf.first] = 0;
 195         nextseq = rtpbuf.seq[rtpbuf.first];
 196         rtpbuf.first = ( 1 + rtpbuf.first ) % MAXRTPPACKETSIN;
 197         rtpbuf.seq[rtpbuf.first] = nextseq + 1;
 198
 199         return length;
 200 }
 201
 202
 203 // Read next rtp packet using cache
 204 int read_rtp_from_server(int fd, char *buffer, int length) {
 205         // Following test is ASSERT (i.e. uneuseful if code is correct)
 206         if(buffer==NULL || length<STREAM_BUFFER_SIZE) {
 207                 mp_msg(MSGT_NETWORK, MSGL_ERR, "RTP buffer invalid; no data return from network\n");
 208                 return 0;
 209         }
 210
 211         // loop just to skip empty packets
 212         while ((length = rtp_get_next(fd, buffer, length)) == 0) {
 213                 mp_msg(MSGT_NETWORK, MSGL_ERR, "Got empty packet from RTP cache!?\n");
 214         }
 215
 216         return(length);
 217 }
 218
 219 static int getrtp2(int fd, struct rtpheader *rh, char** data, int* lengthData) {
 220   static char buf[1600];
 221   unsigned int intP;
 222   char* charP = (char*) &intP;
 223   int headerSize;
 224   int lengthPacket;
 225   lengthPacket=recv(fd,buf,1590,0);
 226   if (lengthPacket<0)
 227     mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: socket read error\n");
 228   else if (lengthPacket<12)
 229     mp_msg(MSGT_NETWORK,MSGL_ERR,"rtp: packet too small (%d) to be an rtp frame (>12bytes)\n", lengthPacket);
 230   if(lengthPacket<12) {
 231     *lengthData = 0;
 232     return 0;
 233   }
 234   rh->b.v  = (unsigned int) ((buf[0]>>6)&0x03);
 235   rh->b.p  = (unsigned int) ((buf[0]>>5)&0x01);
 236   rh->b.x  = (unsigned int) ((buf[0]>>4)&0x01);
 237   rh->b.cc = (unsigned int) ((buf[0]>>0)&0x0f);
 238   rh->b.m  = (unsigned int) ((buf[1]>>7)&0x01);
 239   rh->b.pt = (unsigned int) ((buf[1]>>0)&0x7f);
 240   intP = 0;
 241   memcpy(charP+2,&buf[2],2);
 242   rh->b.sequence = ntohl(intP);
 243   intP = 0;
 244   memcpy(charP,&buf[4],4);
 245   rh->timestamp = ntohl(intP);
 246
 247   headerSize = 12 + 4*rh->b.cc; /* in bytes */
 248
 249   *lengthData = lengthPacket - headerSize;
 250   *data = (char*) buf + headerSize;
 251
 252   //  mp_msg(MSGT_NETWORK,MSGL_DBG2,"Reading rtp: v=%x p=%x x=%x cc=%x m=%x pt=%x seq=%x ts=%x lgth=%d\n",rh->b.v,rh->b.p,rh->b.x,rh->b.cc,rh->b.m,rh->b.pt,rh->b.sequence,rh->timestamp,lengthPacket);
 253
 254   return(0);
 255 }