rtprecv: avoid concurrent r/w of rtcp_peer and cname

src/rtprecv.c

@@ -14,6 +14,13 @@
 #define MAGIC 0x00511eb3
 #include "magic.h"
 
+enum rtcp_state {
+	RTCP_IDLE,
+	RTCP_STARTING,
+	RTCP_RUNNING
+};
+
+
 /* Receive */
 struct rtp_receiver {
 #ifndef RELEASE
@@ -31,7 +38,7 @@ struct rtp_receiver {
 	bool pseq_set;                 /**< True if sequence number is set   */
 	bool rtp_estab;                /**< True if RTP stream established   */
 	RE_ATOMIC bool run;            /**< True if RX thread is running     */
-	bool start_rtcp;               /**< Start RTCP flag                  */
+	enum rtcp_state rtcp_state;    /**< RTCP state                       */
 	char *cname;                   /**< Canonical Name for RTCP send     */
 	struct sa rtcp_peer;           /**< RTCP address of Peer             */
 	bool pinhole;                  /**< Open RTCP NAT pinhole flag       */
@@ -170,11 +177,11 @@ static void rtprecv_periodic(void *arg)
 		mtx_unlock(rx->mtx);
 		tmr_start(&rx->tmr, 10, rtprecv_periodic, rx);
 		mtx_lock(rx->mtx);
-		if (rx->start_rtcp) {
+		if (rx->rtcp_state == RTCP_STARTING) {
 			int err = 0;
-			rx->start_rtcp = false;
-			mtx_unlock(rx->mtx);
+			rx->rtcp_state = RTCP_RUNNING;
 			rtcp_start(rx->rtp, rx->cname, &rx->rtcp_peer);
+			mtx_unlock(rx->mtx);
 			if (pinhole) {
 				err = rtcp_send_app(rx->rtp, "PING",
 						    (void *)"PONG", 4);
@@ -511,7 +518,9 @@ int rtprecv_start_rtcp(struct rtp_receiver *rx, const char *cname,
 
 	rx->cname = mem_deref(rx->cname);
 	err = str_dup(&rx->cname, cname);
-	rx->start_rtcp = true;
+	if (rx->rtcp_state == RTCP_IDLE)
+		rx->rtcp_state = RTCP_STARTING;
+
 	rx->pinhole = pinhole;
 	mtx_unlock(rx->mtx);