rtptrans.c

RTP 实现的工具

        default:
        rtp_hdr_send.pt=115;   /* hopefully unused */
        perror(" unknown codecs ");
        break;
      }
      rtp_hdr_send.ssrc    = sin_from.sin_addr.s_addr;
      rtp_hdr_send.seq     = find_stream(rtp_hdr_send.ssrc, vat_hdr->ts,
         vat_hdr->ts + samples, rtp_hdr_send.m);
      rtp_hdr_send.version = RTP_VERSION;
      rtp_hdr_send.p       = 0;
      rtp_hdr_send.x       = 0;
      rtp_hdr_send.cc      = 0;
      rtp_hdr_send.ts      = vat_hdr->ts;


#ifdef Linux 
      /* 
       * Stupid little Linux does not support sendmsg 
       * use copying instead; contributed by
       * Lutz Grueneberg <[e-mail]>.
       */
      {
        unsigned char mbuf[10000];
        int mlength = 0;
        memcpy (&mbuf[mlength], (char *)&(rtp_hdr_send), sizeof(rtp_hdr_t)-4);
        mlength += sizeof(rtp_hdr_t)-4;
        memcpy (&mbuf[mlength], packet+VAT_LEN, len-VAT_LEN);
        mlength += len-VAT_LEN;
        for (i = 0; i < hostc; i++) {
          if (side[i][proto].sock != sock) {
            if (sendto(side[i][2].sock, mbuf, mlength, 0,
                        &(side[i][proto].sin), sizeof(side[i][proto].sin))!=
                mlength)
              perror("sendmsg RTCP");
          }
        }
      }
#else 
      iov[0].iov_base = (char *)&(rtp_hdr_send);
      iov[0].iov_len = sizeof(rtp_hdr_t)-4;
      iov[1].iov_base = packet+VAT_LEN;
      iov[1].iov_len = len-VAT_LEN;
      msg.msg_iov = iov;
      msg.msg_iovlen = 2;
      for (i = 0; i < hostc; i++) {
        if (side[i][proto].sock != sock) {
          msg.msg_name = (caddr_t ) &side[i][proto].sin;
          msg.msg_namelen = sizeof(side[i][proto].sin);
#if defined(__FreeBSD__) /* Or presumably other BSD 4.4 systems */
	  msg.msg_control = 0;
	  msg.msg_controllen = 0;
#else
          msg.msg_accrights = 0;
          msg.msg_accrightslen = 0;
#endif
          if ((sendmsg(side[i][2].sock, &msg,0))!= 
            iov[0].iov_len +iov[1].iov_len)
            perror("sendmsg RTCP");
          }
       }
    }
#endif /* Linux */
    else if (((struct CtrlMsgHdr *)packet)->type == 1) /* vat ID messages */{
      rtcp_t *rtcp_msg;
      struct sdes_msg *ctl_msg;
      rtcp_sdes_item_t *item;
      int len=0;
      int length;
      item=NULL;

      /* total length of the packet = IP address+ site entry of vat+ 2 type+ 2 
        length + 4 common header+ 4 ssrc + 8 empty RR */
      length = strlen(inet_ntoa(sin_from.sin_addr)) +
        strlen(packet+sizeof(struct CtrlMsgHdr)) + 12 + 8;
      length = ((length/4)*4)+4;
      rtcp_msg=(rtcp_t *)malloc(length);
      memset(rtcp_msg,0,length);

      /* init RR */
      rtcp_msg->common.version=2;
      rtcp_msg->common.p=0;
      rtcp_msg->common.count=0;
      rtcp_msg->common.pt=201;
      rtcp_msg->r.rr.ssrc=sin_from.sin_addr.s_addr;
      rtcp_msg->common.length=(8 >> 2) - 1;

      ctl_msg=(struct sdes_msg *)&rtcp_msg->r.rr.rr[0];
      item=( rtcp_sdes_item_t *) ((char *)ctl_msg+8);
      /* init CNAME */
      item->type=1;
      strcpy(item->data,inet_ntoa(sin_from.sin_addr));
      item->length=strlen(item->data);
      len=item->length+2;

      item=(rtcp_sdes_item_t *)((char *)item +len);
      /* init NAME */
      strcpy(item->data,packet+sizeof(struct CtrlMsgHdr));
      item->length=strlen(item->data);
      item->type=2;
      len+=item->length+2;


      ctl_msg->header.version=2;
      ctl_msg->header.p=0;
      ctl_msg->header.count=1;
      ctl_msg->header.pt=202;
      ctl_msg->sdes.src=sin_from.sin_addr.s_addr;
      ctl_msg->header.length=((length-8) >> 2) - 1;

      for (i = 0; i < hostc; i++) {
        if (side[i][proto].sock != sock) {
          if (sendto(side[i][2].sock,(char *)rtcp_msg,
             ((rtcp_msg->common.length+1)+(ctl_msg->header.length+1))*4,
             0, (struct sockaddr *)&side[i][proto].sin,
             sizeof(side[i][proto].sin)) < 0)
          perror("sendto RTCP");
        }
      }
      free(rtcp_msg);
    }/* control messages */
  }
  return NOTIFY_DONE;
} /* socket_handler */


void usage(char *argv0)
{
  fprintf(stderr, 
"Usage: %s \
[address]/port/ttl\
[address]/port/ttl [...]\n",
 argv0);
}

int main(int argc, char *argv[])
{
  int c;
  struct {
    char *name;
    unsigned char ttl;
    struct sockaddr_in sin;
    struct ip_mreq mreq;
  } host[MAX_HOST];
  struct sockaddr_in sin;   /* generic bind */
  extern int optind;
  char loop = 0;  /* multicast loop */
  int reuse = 1;  /* reuse address */
  int i, j;

  extern struct in_addr host2ip(char *);

  while ((c = getopt(argc, argv, "d?h")) != EOF) {
    switch(c) {
    case 'd':
      debug = 1;
      break;
    case '?':
    case 'h':
      usage(argv[0]);
      exit(1);
      break;
    }
  }

  if (optind == argc) {
    usage(argv[0]);
    exit(1);
  }

  /* Parse host descriptions. */
  for (i = 0; i < argc-optind; i++) {
    char *s;

    if (i >= MAX_HOST) break;
    host[i].ttl  = 16;
    host[i].name = argv[optind+i];
    host[i].sin.sin_family = AF_INET;
    s = strchr(host[i].name, '/');
    if (!s) {
      usage(argv[0]);
      exit(1);
    }
    else {
      int port;

      *s = '\0';
      port = atoi(s+1);
      if (port & 1) {
        fprintf(stderr, "%s: Port must be even.\n", argv[0]);
        /* exit(1); */
      }
      host[i].sin.sin_port = htons(port);
      s = strchr(s+1, '/');
      if (s) {
        host[i].ttl = atoi(s+1);
      }
    }
    host[i].sin.sin_addr = host2ip(host[i].name);
    if (IN_CLASSD(host[i].sin.sin_addr.s_addr)) {
      host[i].mreq.imr_multiaddr        = host[i].sin.sin_addr;
      host[i].mreq.imr_interface.s_addr = htonl(INADDR_ANY);
    }
    hostc++;
  }

  /* Create/bind sockets. */
  for (i = 0; i < hostc; i++) { /* hosts (unicast or multicast) */
    for (j = 0; j < 3; j++) { /* receive ports (RTP, RTCP), send */
      side[i][j].sock = socket(PF_INET, SOCK_DGRAM, 0);
      if (side[i][j].sock < 0) {
        perror("socket");
        exit(1);
      }
      if (setsockopt(side[i][j].sock, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse,
                   sizeof(reuse)) == -1)
        perror("setsockopt: reuseaddr");
      if (j < 2) {
        side[i][j].sin = host[i].sin;
        side[i][j].sin.sin_port = htons(ntohs(host[i].sin.sin_port) + j);
      }
      else {
        side[i][j].sin.sin_addr.s_addr = INADDR_ANY;
        side[i][j].sin.sin_port = 0;
      }

      /* Bind to multicast address. */
      sin = side[i][j].sin;
      if (IN_CLASSD(host[i].sin.sin_addr.s_addr)) {
        if (!multi_sock[j]) {
          multi_sock[j]=side[i][j].sock;  /* save number of multicast socket */
        }
        if (j < 2 && setsockopt(side[i][j].sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
            (char *)&host[i].mreq, sizeof(host[i].mreq)) < 0) {
            perror("IP_ADD_MEMBERSHIP");
            exit(1);
        }
        if (j==2 && setsockopt(side[i][j].sock, IPPROTO_IP, IP_MULTICAST_TTL,
            (char *)&host[i].ttl, sizeof(host[i].ttl)) < 0) {
          perror("IP_MULTICAST_TTL");
          exit(1);
        }
again:
        if (bind(side[i][j].sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
          if (errno == EADDRNOTAVAIL) {
            sin.sin_addr.s_addr = INADDR_ANY;
            goto again;
          }
          else {
            perror("bind multicast");
            exit(1);
          }
        }
        if (j==2 && setsockopt(side[i][j].sock, IPPROTO_IP, IP_MULTICAST_LOOP,
            (char *)&loop, sizeof(loop)) < 0) {
          perror("IP_MULTICAST_LOOP");
          exit(1);
        }
      } /* multicast */
      /* unicast */
      else {
        sin.sin_addr.s_addr = INADDR_ANY;
        if (bind(side[i][j].sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
          perror("bind unicast");
          exit(1);
        }
      }
      if (j < 2) {
        notify_set_input_func((Notify_client)j, socket_handler, 
          side[i][j].sock);
      }
    } /* for j (protocols) */
  } /* for i (hosts) */

  if ((c = notify_start()) != NOTIFY_OK) {
    fprintf(stderr, "%s: Notifier error %d.\n", argv[0], c);
    perror("select");
  };

  return 0;
} /* main */