Add apexsink for audio output to Apple AirPort Express Wireless devices. Fixes bug #542510.

Original commit message from CVS:
Patch by: Jérémie Bernard <gremimail at gmail dot com>
* configure.ac:
* ext/apexsink/LGPL-3.0.txt:
* ext/apexsink/Makefile.am:
* ext/apexsink/gstapexplugin.c: (plugin_init):
* ext/apexsink/gstapexraop.c: (g_strdel), (gst_apexraop_send),
(gst_apexraop_recv), (gst_apexraop_new), (gst_apexraop_free),
(gst_apexraop_set_host), (gst_apexraop_get_host),
(gst_apexraop_set_port), (gst_apexraop_get_port),
(gst_apexraop_set_useragent), (gst_apexraop_get_useragent),
(gst_apexraop_connect), (gst_apexraop_get_jacktype),
(gst_apexraop_get_jackstatus), (gst_apexraop_close),
(gst_apexraop_set_volume), (gst_apexraop_write_bits),
(gst_apexraop_write), (gst_apexraop_flush):
* ext/apexsink/gstapexraop.h:
* ext/apexsink/gstapexsink.c: (gst_apexsink_jackstatus_get_type),
(gst_apexsink_jacktype_get_type), (gst_apexsink_interfaces_init),
(gst_apexsink_implements_interface_init),
(gst_apexsink_mixer_interface_init),
(gst_apexsink_interface_supported),
(gst_apexsink_mixer_list_tracks), (gst_apexsink_mixer_set_volume),
(gst_apexsink_mixer_get_volume), (gst_apexsink_base_init),
(gst_apexsink_class_init), (gst_apexsink_init),
(gst_apexsink_set_property), (gst_apexsink_get_property),
(gst_apexsink_finalise), (gst_apexsink_open),
(gst_apexsink_prepare), (gst_apexsink_write),
(gst_apexsink_unprepare), (gst_apexsink_delay),
(gst_apexsink_reset), (gst_apexsink_close):
* ext/apexsink/gstapexsink.h:
Add apexsink for audio output to Apple AirPort Express Wireless
devices. Fixes bug #542510.

1 files changed, 690 insertions, 0 deletions

diff --git a/ext/apexsink/gstapexraop.c b/ext/apexsink/gstapexraop.c
new file mode 100644
index 00000000..164a4ccf
--- /dev/null
+++ b/ext/apexsink/gstapexraop.c
@@ -0,0 +1,690 @@
+/* GStreamer - Remote Audio Access Protocol (RAOP) as used in Apple iTunes to stream music to the Airport Express (ApEx) -
+ *
+ * RAOP is based on the Real Time Streaming Protocol (RTSP) but with an extra challenge-response RSA based authentication step.
+ * This interface accepts RAW PCM data and set it as AES encrypted ALAC while performing emission.
+ *
+ * Copyright (C) 2008 Jérémie Bernard [GRemi] <gremimail@gmail.com>
+ *
+ * gstapexraop.c
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstapexraop.h"
+
+/* private constants */
+#define GST_APEX_RAOP_VOLUME_MIN 	-144
+#define GST_APEX_RAOP_VOLUME_MAX  	 0
+
+#define GST_APEX_RAOP_HDR_DEFAULT_LENGTH 1024
+#define GST_APEX_RAOP_SDP_DEFAULT_LENGTH 2048
+
+const static gchar GST_APEX_RAOP_RSA_PUBLIC_MOD[] =
+    "59dE8qLieItsH1WgjrcFRKj6eUWqi+bGLOX1HL3U3GhC/j0Qg90u3sG/1CUtwC"
+    "5vOYvfDmFI6oSFXi5ELabWJmT2dKHzBJKa3k9ok+8t9ucRqMd6DZHJ2YCCLlDR"
+    "KSKv6kDqnw4UwPdpOMXziC/AMj3Z/lUVX1G7WSHCAWKf1zNS1eLvqr+boEjXuB"
+    "OitnZ/bDzPHrTOZz0Dew0uowxf/+sG+NCK3eQJVxqcaJ/vEHKIVd2M+5qL71yJ"
+    "Q+87X6oV3eaYvt3zWZYD6z5vYTcrtij2VZ9Zmni/UAaHqn9JdsBWLUEpVviYnh"
+    "imNVvYFZeCXg/IdTQ+x4IRdiXNv5hEew==";
+
+const static gchar GST_APEX_RAOP_RSA_PUBLIC_EXP[] = "AQAB";
+
+const static gchar GST_APEX_RAOP_USER_AGENT[] =
+    "iTunes/4.6 (Macintosh; U; PPC Mac OS X 10.3)";
+
+const static guchar GST_APEX_RAOP_FRAME_HEADER[] = {
+  0x24, 0x00, 0x00, 0x00,
+  0xF0, 0xFF, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00
+};
+
+const static int GST_APEX_RAOP_FRAME_HEADER_SIZE = 16;
+
+const static int GST_APEX_RAOP_ALAC_HEADER_SIZE = 3;
+
+/* string extra utility */
+static gint
+g_strdel (gchar * str, gchar rc)
+{
+  int i = 0, j = 0, len, num = 0;
+  len = strlen (str);
+  while (i < len) {
+    if (str[i] == rc) {
+      for (j = i; j < len; j++)
+        str[j] = str[j + 1];
+      len--;
+      num++;
+    } else {
+      i++;
+    }
+  }
+  return num;
+}
+
+/* socket utilities */
+static int
+gst_apexraop_send (int desc, void *data, size_t len)
+{
+  int total = 0, bytesleft = len, n = 0;
+
+  while (total < len) {
+    n = send (desc, ((const char *) data) + total, bytesleft, 0);
+    if (n == -1)
+      break;
+    total += n;
+    bytesleft -= n;
+  }
+
+  return n == -1 ? -1 : total;
+}
+
+static int
+gst_apexraop_recv (int desc, void *data, size_t len)
+{
+  bzero (data, len);
+  return recv (desc, data, len, 0);
+}
+
+/* public opaque handle resolution */
+typedef struct
+{
+  guchar aes_ky[AES_BLOCK_SIZE];        /* AES random key */
+  guchar aes_iv[AES_BLOCK_SIZE];        /* AES random initial vector */
+
+  guchar url_abspath[16];       /* header url random absolute path addon, ANNOUNCE id */
+  gint cseq;                    /* header rtsp inc cseq */
+  guchar cid[24];               /* header client instance id */
+  gchar *session;               /* header raop negotiated session id, once SETUP performed */
+  gchar *ua;                    /* header user agent */
+
+  GstApExJackType jack_type;    /* APEX connected jack type, once ANNOUNCE performed */
+  GstApExJackStatus jack_status;        /* APEX connected jack status, once ANNOUNCE performed */
+
+  gchar *host;                  /* APEX target ip */
+  guint ctrl_port;              /* APEX target control port */
+  guint data_port;              /* APEX negotiated data port, once SETUP performed */
+
+  int ctrl_sd;                  /* control socket */
+  struct sockaddr_in ctrl_sd_in;
+
+  int data_sd;                  /* data socket */
+  struct sockaddr_in data_sd_in;
+}
+_GstApExRAOP;
+
+/* raop apex struct allocation */
+GstApExRAOP *
+gst_apexraop_new (const gchar * host, const guint16 port)
+{
+  _GstApExRAOP *apexraop;
+
+  apexraop = (_GstApExRAOP *) g_malloc0 (sizeof (_GstApExRAOP));
+
+  apexraop->host = g_strdup (host);
+  apexraop->ctrl_port = port;
+  apexraop->ua = g_strdup (GST_APEX_RAOP_USER_AGENT);
+  apexraop->jack_type = GST_APEX_JACK_TYPE_UNDEFINED;
+  apexraop->jack_status = GST_APEX_JACK_STATUS_DISCONNECTED;
+
+  return (GstApExRAOP *) apexraop;
+}
+
+/* raop apex struct freeing */
+void
+gst_apexraop_free (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  g_free (conn->host);
+  g_free (conn->session);
+  g_free (conn->ua);
+  g_free (conn);
+}
+
+/* host affectation */
+void
+gst_apexraop_set_host (GstApExRAOP * con, const gchar * host)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  g_free (conn->host);
+  conn->host = g_strdup (host);
+}
+
+/* host reader */
+gchar *
+gst_apexraop_get_host (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  return g_strdup (conn->host);
+}
+
+/* control port affectation */
+void
+gst_apexraop_set_port (GstApExRAOP * con, const guint16 port)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  conn->ctrl_port = port;
+}
+
+/* control port reader */
+guint16
+gst_apexraop_get_port (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  return conn->ctrl_port;
+}
+
+/* user agent affectation */
+void
+gst_apexraop_set_useragent (GstApExRAOP * con, const gchar * useragent)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  g_free (conn->ua);
+  conn->ua = g_strdup (useragent);
+}
+
+/* user agent reader */
+gchar *
+gst_apexraop_get_useragent (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+  conn = (_GstApExRAOP *) con;
+
+  return g_strdup (conn->ua);
+}
+
+/* raop apex connection sequence */
+GstRTSPStatusCode
+gst_apexraop_connect (GstApExRAOP * con)
+{
+  gchar *ac, *ky, *iv, *s, inaddr[INET_ADDRSTRLEN],
+      creq[GST_APEX_RAOP_SDP_DEFAULT_LENGTH],
+      hreq[GST_APEX_RAOP_HDR_DEFAULT_LENGTH], *req;
+  RSA *rsa;
+  guchar *mod, *exp, buf[4 + 8 + 16], rsakey[512];
+  gsize size;
+  struct sockaddr_in ioaddr;
+  socklen_t iolen;
+  GstRTSPStatusCode res;
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  if ((conn->ctrl_sd = socket (AF_INET, SOCK_STREAM, 0)) < 0)
+    return GST_RTSP_STS_DESTINATION_UNREACHABLE;
+
+  conn->ctrl_sd_in.sin_family = AF_INET;
+  conn->ctrl_sd_in.sin_port = htons (conn->ctrl_port);
+
+  if (!inet_aton (conn->host, &conn->ctrl_sd_in.sin_addr)) {
+    struct hostent *hp = (struct hostent *) gethostbyname (conn->host);
+    if (hp == NULL)
+      return GST_RTSP_STS_DESTINATION_UNREACHABLE;
+    memcpy (&conn->ctrl_sd_in.sin_addr, hp->h_addr, hp->h_length);
+  }
+
+  if (connect (conn->ctrl_sd, (struct sockaddr *) &conn->ctrl_sd_in,
+          sizeof (conn->ctrl_sd_in)) < 0)
+    return GST_RTSP_STS_DESTINATION_UNREACHABLE;
+
+  RAND_bytes (buf, sizeof (buf));
+  sprintf ((gchar *) conn->url_abspath, "%lu", *((gulong *) buf));
+  ac = g_base64_encode (buf + 12, 16);
+  g_strdel (ac, '=');
+  sprintf ((char *) conn->cid, "%08lx%08lx", *((gulong *) (buf + 4)),
+      *((gulong *) (buf + 8)));
+
+  RAND_bytes (conn->aes_ky, AES_BLOCK_SIZE);
+  RAND_bytes (conn->aes_iv, AES_BLOCK_SIZE);
+
+  rsa = RSA_new ();
+  mod = g_base64_decode (GST_APEX_RAOP_RSA_PUBLIC_MOD, &size);
+  rsa->n = BN_bin2bn (mod, size, NULL);
+  exp = g_base64_decode (GST_APEX_RAOP_RSA_PUBLIC_EXP, &size);
+  rsa->e = BN_bin2bn (exp, size, NULL);
+  size =
+      RSA_public_encrypt (AES_BLOCK_SIZE, conn->aes_ky, rsakey, rsa,
+      RSA_PKCS1_OAEP_PADDING);
+
+  ky = g_base64_encode (rsakey, size);
+  iv = g_base64_encode (conn->aes_iv, AES_BLOCK_SIZE);
+  g_strdel (ky, '=');
+  g_strdel (iv, '=');
+
+  iolen = sizeof (struct sockaddr);
+  getsockname (conn->ctrl_sd, (struct sockaddr *) &ioaddr, &iolen);
+  inet_ntop (AF_INET, &(ioaddr.sin_addr), inaddr, INET_ADDRSTRLEN);
+
+  sprintf (creq,
+      "v=0\r\n"
+      "o=iTunes %s 0 IN IP4 %s\r\n"
+      "s=iTunes\r\n"
+      "c=IN IP4 %s\r\n"
+      "t=0 0\r\n"
+      "m=audio 0 RTP/AVP 96\r\n"
+      "a=rtpmap:96 AppleLossless\r\n"
+      "a=fmtp:96 %d 0 %d 40 10 14 %d 255 0 0 %d\r\n"
+      "a=rsaaeskey:%s\r\n"
+      "a=aesiv:%s\r\n",
+      conn->url_abspath,
+      inaddr,
+      conn->host,
+      GST_APEX_RAOP_SAMPLES_PER_FRAME,
+      GST_APEX_RAOP_BYTES_PER_CHANNEL * 8,
+      GST_APEX_RAOP_CHANNELS, GST_APEX_RAOP_BITRATE, ky, iv);
+
+  sprintf (hreq,
+      "ANNOUNCE rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Content-Type: application/sdp\r\n"
+      "Content-Length: %d\r\n"
+      "Apple-Challenge: %s\r\n",
+      conn->host,
+      conn->url_abspath, ++conn->cseq, conn->cid, conn->ua, strlen (creq), ac);
+
+  RSA_free (rsa);
+  g_free (ky);
+  g_free (iv);
+  g_free (ac);
+  g_free (mod);
+  g_free (exp);
+
+  req = g_strconcat (hreq, "\r\n", creq, NULL);
+
+  if (gst_apexraop_send (conn->ctrl_sd, req, strlen (req)) <= 0) {
+    g_free (req);
+    return GST_RTSP_STS_GONE;
+  }
+
+  g_free (req);
+
+  if (gst_apexraop_recv (conn->ctrl_sd, hreq,
+          GST_APEX_RAOP_HDR_DEFAULT_LENGTH) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  sscanf (hreq, "%*s %d", (int *) &res);
+
+  if (res != GST_RTSP_STS_OK)
+    return res;
+
+  s = g_strrstr (hreq, "Audio-Jack-Status");
+
+  if (s != NULL) {
+    gchar status[128];
+    sscanf (s, "%*s %s", status);
+
+    if (strcmp (status, "connected;") == 0)
+      conn->jack_status = GST_APEX_JACK_STATUS_CONNECTED;
+    else if (strcmp (status, "disconnected;") == 0)
+      conn->jack_status = GST_APEX_JACK_STATUS_DISCONNECTED;
+    else
+      conn->jack_status = GST_APEX_JACK_STATUS_UNDEFINED;
+
+    s = g_strrstr (s, "type=");
+
+    if (s != NULL) {
+      strtok (s, "=");
+      s = strtok (NULL, "\n");
+
+      if (strcmp (s, "analog"))
+        conn->jack_type = GST_APEX_JACK_TYPE_ANALOG;
+      else if (strcmp (s, "digital"))
+        conn->jack_type = GST_APEX_JACK_TYPE_DIGITAL;
+      else
+        conn->jack_type = GST_APEX_JACK_TYPE_UNDEFINED;
+    }
+  }
+
+  sprintf (hreq,
+      "SETUP rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Transport: RTP/AVP/TCP;unicast;interleaved=0-1;mode=record\r\n"
+      "\r\n", conn->host, conn->url_abspath, ++conn->cseq, conn->cid, conn->ua);
+
+  if (gst_apexraop_send (conn->ctrl_sd, hreq, strlen (hreq)) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  if (gst_apexraop_recv (conn->ctrl_sd, hreq,
+          GST_APEX_RAOP_HDR_DEFAULT_LENGTH) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  sscanf (hreq, "%*s %d", (int *) &res);
+
+  if (res != GST_RTSP_STS_OK)
+    return res;
+
+  s = g_strrstr (hreq, "Session");
+
+  if (s != NULL) {
+    gchar session[128];
+    sscanf (s, "%*s %s", session);
+    conn->session = g_strdup (session);
+  } else
+    return GST_RTSP_STS_PRECONDITION_FAILED;
+
+  s = g_strrstr (hreq, "server_port");
+  if (s != NULL) {
+    sscanf (s, "server_port=%d", &conn->data_port);
+  } else
+    return GST_RTSP_STS_PRECONDITION_FAILED;
+
+  sprintf (hreq,
+      "RECORD rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Session: %s\r\n"
+      "Range: npt=0-\r\n"
+      "RTP-Info: seq=0;rtptime=0\r\n"
+      "\r\n",
+      conn->host,
+      conn->url_abspath, ++conn->cseq, conn->cid, conn->ua, conn->session);
+
+  if (gst_apexraop_send (conn->ctrl_sd, hreq, strlen (hreq)) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  if (gst_apexraop_recv (conn->ctrl_sd, hreq,
+          GST_APEX_RAOP_HDR_DEFAULT_LENGTH) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  sscanf (hreq, "%*s %d", (int *) &res);
+
+  if (res != GST_RTSP_STS_OK)
+    return res;
+
+  if ((conn->data_sd = socket (AF_INET, SOCK_STREAM, 0)) < 0)
+    return GST_RTSP_STS_DESTINATION_UNREACHABLE;
+
+  conn->data_sd_in.sin_family = AF_INET;
+  conn->data_sd_in.sin_port = htons (conn->data_port);
+
+  memcpy (&conn->data_sd_in.sin_addr, &conn->ctrl_sd_in.sin_addr,
+      sizeof (conn->ctrl_sd_in.sin_addr));
+
+  if (connect (conn->data_sd, (struct sockaddr *) &conn->data_sd_in,
+          sizeof (conn->data_sd_in)) < 0)
+    return GST_RTSP_STS_DESTINATION_UNREACHABLE;
+
+  return res;
+}
+
+/* raop apex jack type access */
+GstApExJackType
+gst_apexraop_get_jacktype (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  if (!conn)
+    return GST_APEX_JACK_TYPE_UNDEFINED;
+
+  return conn->jack_type;
+}
+
+/* raop apex jack status access */
+GstApExJackStatus
+gst_apexraop_get_jackstatus (GstApExRAOP * con)
+{
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  if (!conn)
+    return GST_APEX_JACK_STATUS_UNDEFINED;
+
+  return conn->jack_status;
+}
+
+/* raop apex sockets close */
+void
+gst_apexraop_close (GstApExRAOP * con)
+{
+  gchar hreq[GST_APEX_RAOP_HDR_DEFAULT_LENGTH];
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  sprintf (hreq,
+      "TEARDOWN rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Session: %s\r\n"
+      "\r\n",
+      conn->host,
+      conn->url_abspath, ++conn->cseq, conn->cid, conn->ua, conn->session);
+
+  gst_apexraop_send (conn->ctrl_sd, hreq, strlen (hreq));
+  gst_apexraop_recv (conn->ctrl_sd, hreq, GST_APEX_RAOP_HDR_DEFAULT_LENGTH);
+
+  if (conn->ctrl_sd != 0)
+    close (conn->ctrl_sd);
+  if (conn->data_sd != 0)
+    close (conn->data_sd);
+}
+
+/* raop apex volume set */
+GstRTSPStatusCode
+gst_apexraop_set_volume (GstApExRAOP * con, const guint volume)
+{
+  gint v;
+  gchar creq[GST_APEX_RAOP_SDP_DEFAULT_LENGTH],
+      hreq[GST_APEX_RAOP_HDR_DEFAULT_LENGTH], *req, vol[128];
+  GstRTSPStatusCode res;
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  v = GST_APEX_RAOP_VOLUME_MIN + (GST_APEX_RAOP_VOLUME_MAX -
+      GST_APEX_RAOP_VOLUME_MIN) * volume / 100.;
+  sprintf (vol, "volume: %d.000000\r\n", v);
+
+  sprintf (creq, "%s\r\n", vol);
+
+  sprintf (hreq,
+      "SET_PARAMETER rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Session: %s\r\n"
+      "Content-Type: text/parameters\r\n"
+      "Content-Length: %d\r\n",
+      conn->host,
+      conn->url_abspath,
+      ++conn->cseq, conn->cid, conn->ua, conn->session, strlen (creq)
+      );
+
+  req = g_strconcat (hreq, "\r\n", creq, NULL);
+
+  if (gst_apexraop_send (conn->ctrl_sd, req, strlen (req)) <= 0) {
+    g_free (req);
+    return GST_RTSP_STS_GONE;
+  }
+
+  g_free (req);
+
+  if (gst_apexraop_recv (conn->ctrl_sd, hreq,
+          GST_APEX_RAOP_HDR_DEFAULT_LENGTH) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  sscanf (hreq, "%*s %d", (int *) &res);
+
+  return res;
+}
+
+/* raop apex raw data alac encapsulation, encryption and emission, http://wiki.multimedia.cx/index.php?title=Apple_Lossless_Audio_Coding */
+static void inline
+gst_apexraop_write_bits (guchar * buffer, int data, int numbits,
+    int *bit_offset, int *byte_offset)
+{
+  const static guchar masks[] =
+      { 0x01, 0x03, 0x07, 0x0F, 0x1F, 0x3F, 0x7F, 0xFF };
+
+  if (((*bit_offset) != 0) && (((*bit_offset) + numbits) > 8)) {
+    gint numwritebits;
+    guchar bitstowrite;
+
+    numwritebits = 8 - (*bit_offset);
+    bitstowrite =
+        (guchar) ((data >> (numbits - numwritebits)) << (8 - (*bit_offset) -
+            numwritebits));
+    buffer[(*byte_offset)] |= bitstowrite;
+    numbits -= numwritebits;
+    (*bit_offset) = 0;
+    (*byte_offset)++;
+  }
+
+  while (numbits >= 8) {
+    guchar bitstowrite;
+
+    bitstowrite = (guchar) ((data >> (numbits - 8)) & 0xFF);
+    buffer[(*byte_offset)] |= bitstowrite;
+    numbits -= 8;
+    (*bit_offset) = 0;
+    (*byte_offset)++;
+  }
+
+  if (numbits > 0) {
+    guchar bitstowrite;
+    bitstowrite =
+        (guchar) ((data & masks[numbits]) << (8 - (*bit_offset) - numbits));
+    buffer[(*byte_offset)] |= bitstowrite;
+    (*bit_offset) += numbits;
+    if ((*bit_offset) == 8) {
+      (*byte_offset)++;
+      (*bit_offset) = 0;
+    }
+  }
+}
+
+guint
+gst_apexraop_write (GstApExRAOP * con, gpointer rawdata, guint length)
+{
+  guchar *buffer, *frame_data;
+  gushort len;
+  gint bit_offset, byte_offset, i, out_len, res;
+  EVP_CIPHER_CTX aes_ctx;
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  buffer =
+      (guchar *) g_malloc0 (GST_APEX_RAOP_FRAME_HEADER_SIZE +
+      GST_APEX_RAOP_ALAC_HEADER_SIZE + length);
+
+  memcpy (buffer, GST_APEX_RAOP_FRAME_HEADER, GST_APEX_RAOP_FRAME_HEADER_SIZE);
+
+  len =
+      length + GST_APEX_RAOP_FRAME_HEADER_SIZE +
+      GST_APEX_RAOP_ALAC_HEADER_SIZE - 4;
+  buffer[2] = len >> 8;
+  buffer[3] = len & 0xff;
+
+  bit_offset = 0;
+  byte_offset = 0;
+  frame_data = buffer + GST_APEX_RAOP_FRAME_HEADER_SIZE;
+
+  gst_apexraop_write_bits (frame_data, 1, 3, &bit_offset, &byte_offset);        /* channels, 0 mono, 1 stereo */
+  gst_apexraop_write_bits (frame_data, 0, 4, &bit_offset, &byte_offset);        /* unknown */
+  gst_apexraop_write_bits (frame_data, 0, 8, &bit_offset, &byte_offset);        /* unknown (12 bits) */
+  gst_apexraop_write_bits (frame_data, 0, 4, &bit_offset, &byte_offset);
+  gst_apexraop_write_bits (frame_data, 0, 1, &bit_offset, &byte_offset);        /* has size flag */
+  gst_apexraop_write_bits (frame_data, 0, 2, &bit_offset, &byte_offset);        /* unknown */
+  gst_apexraop_write_bits (frame_data, 1, 1, &bit_offset, &byte_offset);        /* no compression flag */
+
+  for (i = 0; i < length; i += 2) {
+    gst_apexraop_write_bits (frame_data, ((guchar *) rawdata)[i + 1], 8,
+        &bit_offset, &byte_offset);
+    gst_apexraop_write_bits (frame_data, ((guchar *) rawdata)[i], 8,
+        &bit_offset, &byte_offset);
+  }
+
+  EVP_CIPHER_CTX_init (&aes_ctx);
+  EVP_CipherInit_ex (&aes_ctx, EVP_aes_128_cbc (), NULL, conn->aes_ky,
+      conn->aes_iv, AES_ENCRYPT);
+  EVP_CipherUpdate (&aes_ctx, frame_data, &out_len, frame_data, /*( */
+      GST_APEX_RAOP_ALAC_HEADER_SIZE +
+      length /*) / AES_BLOCK_SIZE * AES_BLOCK_SIZE */ );
+  EVP_CIPHER_CTX_cleanup (&aes_ctx);
+
+  res =
+      gst_apexraop_send (conn->data_sd, buffer,
+      GST_APEX_RAOP_FRAME_HEADER_SIZE + GST_APEX_RAOP_ALAC_HEADER_SIZE +
+      length);
+
+  g_free (buffer);
+
+  return (guint) ((res >=
+          (GST_APEX_RAOP_FRAME_HEADER_SIZE +
+              GST_APEX_RAOP_ALAC_HEADER_SIZE)) ? (res -
+          GST_APEX_RAOP_FRAME_HEADER_SIZE -
+          GST_APEX_RAOP_ALAC_HEADER_SIZE) : 0);
+}
+
+/* raop apex buffer flush */
+GstRTSPStatusCode
+gst_apexraop_flush (GstApExRAOP * con)
+{
+  gchar hreq[GST_APEX_RAOP_HDR_DEFAULT_LENGTH];
+  GstRTSPStatusCode res;
+  _GstApExRAOP *conn;
+
+  conn = (_GstApExRAOP *) con;
+
+  sprintf (hreq,
+      "FLUSH rtsp://%s/%s RTSP/1.0\r\n"
+      "CSeq: %d\r\n"
+      "Client-Instance: %s\r\n"
+      "User-Agent: %s\r\n"
+      "Session: %s\r\n"
+      "RTP-Info: seq=0;rtptime=0\r\n"
+      "\r\n",
+      conn->host,
+      conn->url_abspath, ++conn->cseq, conn->cid, conn->ua, conn->session);
+
+  if (gst_apexraop_send (conn->ctrl_sd, hreq, strlen (hreq)) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  if (gst_apexraop_recv (conn->ctrl_sd, hreq,
+          GST_APEX_RAOP_HDR_DEFAULT_LENGTH) <= 0)
+    return GST_RTSP_STS_GONE;
+
+  sscanf (hreq, "%*s %d", (int *) &res);
+
+  return res;
+}