From c36930535d5a20476aaa403477c51c76640a45a1 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Aleix=20Conchillo=20Flaqu=C3=A9?= <aleix@oblong.com>
Date: Fri, 15 Apr 2016 00:46:56 -0700
Subject: [PATCH] rtspsrc: add srtp rollover counters from mikey crypto
 sessions

The server can send multiple crypto sessions, one for each SSRC with its
own rollover counter. We parse this information and pass it to the SRTP
decoder via the "request-key" signal.

https://bugzilla.gnome.org/show_bug.cgi?id=730540
---
 gst/rtsp/gstrtspsrc.c | 31 +++++++++++++++++++++++++++++--
 gst/rtsp/gstrtspsrc.h |  3 +++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/gst/rtsp/gstrtspsrc.c b/gst/rtsp/gstrtspsrc.c
index e2b3a41..9b54dbc 100644
--- a/gst/rtsp/gstrtspsrc.c
+++ b/gst/rtsp/gstrtspsrc.c
@@ -1523,6 +1523,11 @@ gst_rtspsrc_collect_payloads (GstRTSPSrc * src, const GstSDPMessage * sdp,
   GST_DEBUG ("mapping sdp media level attributes to caps");
   gst_sdp_media_attributes_to_caps (media, global_caps);
 
+  /* Keep a copy of the SDP key management */
+  gst_sdp_media_parse_keymgmt (media, &stream->mikey);
+  if (stream->mikey == NULL)
+    gst_sdp_message_parse_keymgmt (sdp, &stream->mikey);
+
   len = gst_sdp_media_formats_len (media);
   for (i = 0; i < len; i++) {
     gint pt;
@@ -1632,6 +1637,7 @@ gst_rtspsrc_create_stream (GstRTSPSrc * src, GstSDPMessage * sdp, gint idx)
   stream->send_ssrc = g_random_int ();
   stream->profile = GST_RTSP_PROFILE_AVP;
   stream->ptmap = g_array_new (FALSE, FALSE, sizeof (PtMapItem));
+  stream->mikey = NULL;
   g_array_set_clear_func (stream->ptmap, (GDestroyNotify) clear_ptmap_item);
 
   /* collect bandwidth information for this steam. FIXME, configure in the RTP
@@ -1741,6 +1747,8 @@ gst_rtspsrc_stream_free (GstRTSPSrc * src, GstRTSPStream * stream)
     gst_object_unref (stream->srtpdec);
   if (stream->srtcpparams)
     gst_caps_unref (stream->srtcpparams);
+  if (stream->mikey)
+    gst_mikey_message_unref (stream->mikey);
   if (stream->rtcppad)
     gst_object_unref (stream->rtcppad);
   if (stream->session)
@@ -2747,8 +2755,27 @@ set_manager_buffer_mode (GstRTSPSrc * src)
 static GstCaps *
 request_key (GstElement * srtpdec, guint ssrc, GstRTSPStream * stream)
 {
-  GST_DEBUG ("request key %u", ssrc);
-  return gst_caps_ref (stream_get_caps_for_pt (stream, stream->default_pt));
+  guint i;
+  GstCaps *caps;
+  GstMIKEYMessage *msg = stream->mikey;
+
+  GST_DEBUG ("request key SSRC %u", ssrc);
+
+  caps = gst_caps_ref (stream_get_caps_for_pt (stream, stream->default_pt));
+  caps = gst_caps_make_writable (caps);
+
+  /* parse crypto sessions and look for the SSRC rollover counter */
+  msg = stream->mikey;
+  for (i = 0; msg && i < gst_mikey_message_get_n_cs (msg); i++) {
+    const GstMIKEYMapSRTP *map = gst_mikey_message_get_cs_srtp (msg, i);
+
+    if (ssrc == map->ssrc) {
+      gst_caps_set_simple (caps, "roc", G_TYPE_UINT, map->roc, NULL);
+      break;
+    }
+  }
+
+  return caps;
 }
 
 static GstElement *
diff --git a/gst/rtsp/gstrtspsrc.h b/gst/rtsp/gstrtspsrc.h
index df1741c..a665754 100644
--- a/gst/rtsp/gstrtspsrc.h
+++ b/gst/rtsp/gstrtspsrc.h
@@ -144,6 +144,9 @@ struct _GstRTSPStream {
   /* session */
   GObject      *session;
 
+  /* srtp key management */
+  GstMIKEYMessage *mikey;
+
   /* bandwidth */
   guint         as_bandwidth;
   guint         rs_bandwidth;
-- 
2.7.4