bridge.c: Hangup attended transfer target if bridged

After completing an attended transfer the transfer target channel was not being
hung up after leaving the bridge. Added an explicit softhangup to hangup said
channel, but only if it was previously bridged.

ASTERISK-24782 #close
Reported by: John Bigelow

Change-Id: Idde9543d56842369384a5e8c00d72a22bbc39ada

main/bridge.c

@@ -4389,6 +4389,7 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	int do_bridge_transfer;
 	enum ast_transfer_result res;
 	const char *app = NULL;
+	int hangup_target = 0;
 
 	to_transferee_bridge = acquire_bridge(to_transferee);
 	to_target_bridge = acquire_bridge(to_transfer_target);
@@ -4468,7 +4469,7 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 		ast_bridge_unlock(to_transferee_bridge);
 		ast_bridge_unlock(to_target_bridge);
 
-		ast_softhangup(to_transfer_target, AST_SOFTHANGUP_DEV);
+		hangup_target = 1;
 		goto end;
 	}
 
@@ -4511,6 +4512,11 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	set_transfer_variables_all(to_transferee, channels, 1);
 
 	if (do_bridge_transfer) {
+		/*
+		 * Hang up the target if it was bridged. Note, if it is not bridged
+		 * it is hung up during the masquerade.
+		 */
+		hangup_target = chan_bridged == to_transfer_target;
 		ast_bridge_lock(the_bridge);
 		res = attended_transfer_bridge(chan_bridged, chan_unbridged, the_bridge, NULL, transfer_msg);
 		ast_bridge_unlock(the_bridge);
@@ -4534,6 +4540,10 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	res = AST_BRIDGE_TRANSFER_SUCCESS;
 
 end:
+	if (res == AST_BRIDGE_TRANSFER_SUCCESS && hangup_target) {
+		ast_softhangup(to_transfer_target, AST_SOFTHANGUP_DEV);
+	}
+
 	transfer_msg->result = res;
 	ast_bridge_publish_attended_transfer(transfer_msg);
 	return res;