Relay cause of hangup on SRTP failure

We hangup the channel after receiving 10 SRTP packets in a row with a
bad auth tag or that are replayed.  Prior to this commit we were
indicating a normal clearing.  When doing interop and looking first at
packet traces, this made freeswitch's behavior look surprising.  With
this commit we'll indicate more loudly what's happening.

src/include/switch_types.h

@@ -1968,7 +1968,8 @@ typedef enum {
 	SWITCH_CAUSE_GATEWAY_DOWN = 609,
 	SWITCH_CAUSE_INVALID_URL = 610,
 	SWITCH_CAUSE_INVALID_PROFILE = 611,
-	SWITCH_CAUSE_NO_PICKUP = 612
+	SWITCH_CAUSE_NO_PICKUP = 612,
+	SWITCH_CAUSE_SRTP_READ_ERROR = 613
 } switch_call_cause_t;
 
 typedef enum {

src/switch_channel.c

@@ -123,6 +123,7 @@ static struct switch_cause_table CAUSE_CHART[] = {
 	{"INVALID_URL", SWITCH_CAUSE_INVALID_URL},
 	{"INVALID_PROFILE", SWITCH_CAUSE_INVALID_PROFILE},
 	{"NO_PICKUP", SWITCH_CAUSE_NO_PICKUP},
+	{"SRTP_READ_ERROR", SWITCH_CAUSE_SRTP_READ_ERROR},
 	{NULL, 0}
 };
 

src/switch_rtp.c

@@ -4802,15 +4802,14 @@ static switch_status_t read_rtp_packet(switch_rtp_t *rtp_session, switch_size_t
 
 				if (stat && rtp_session->recv_msg.header.pt != rtp_session->recv_te && rtp_session->recv_msg.header.pt != rtp_session->cng_pt) {
 					if (++rtp_session->srtp_errs[rtp_session->srtp_idx_rtp] >= MAX_SRTP_ERRS && stat != 10) {
-						
+						switch_channel_t *channel = switch_core_session_get_channel(rtp_session->session);
 						switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(rtp_session->session), SWITCH_LOG_ERROR,
 										  "Error: SRTP %s unprotect failed with code %d%s %ld\n", rtp_type(rtp_session), stat,
 										  stat == err_status_replay_fail ? " (replay check failed)" : stat ==
 										  err_status_auth_fail ? " (auth check failed)" : "", (long)*bytes);
-						return SWITCH_STATUS_GENERR;
-					} else {
-						sbytes = 0;
+						switch_channel_hangup(channel, SWITCH_CAUSE_SRTP_READ_ERROR);
 					}
+					sbytes = 0;
 				} else {
 					rtp_session->srtp_errs[rtp_session->srtp_idx_rtp] = 0;
 				}