samples: reel_board/mesh_badge: Add protection for fast key presses

It was possible to freeze the application by pressing the user button
too frequently. This was likely due to the stack not keeping up with
the send requests and running out of buffers.

Add rate-limiting to the app, so that at most one message per 500ms
can be sent. Also add a user message if the user presses the button
too many times in rapid succession, and inform the other badges of
this misbehaving user.

Signed-off-by: Johan Hedberg <[email protected]>

Author: Johan Hedberg

samples/boards/reel_board/mesh_badge/src/mesh.c

@@ -20,8 +20,10 @@
 #define MOD_LF            0x0000
 #define OP_HELLO          0xbb
 #define OP_HEARTBEAT      0xbc
+#define OP_BADUSER        0xbd
 #define OP_VND_HELLO      BT_MESH_MODEL_OP_3(OP_HELLO, BT_COMP_ID_LF)
 #define OP_VND_HEARTBEAT  BT_MESH_MODEL_OP_3(OP_HEARTBEAT, BT_COMP_ID_LF)
+#define OP_VND_BADUSER    BT_MESH_MODEL_OP_3(OP_BADUSER, BT_COMP_ID_LF)
 
 #define DEFAULT_TTL       31
 #define GROUP_ADDR        0xc123
@@ -56,6 +58,7 @@ struct sensor_hdr_b {
 } __packed;
 
 static struct k_work hello_work;
+static struct k_work baduser_work;
 static struct k_work mesh_start_work;
 
 /* Definitions of models user data (Start) */
@@ -334,6 +337,30 @@ static void vnd_hello(struct bt_mesh_model *model,
 	board_blink_leds();
 }
 
+static void vnd_baduser(struct bt_mesh_model *model,
+			struct bt_mesh_msg_ctx *ctx,
+			struct net_buf_simple *buf)
+{
+	char str[32];
+	size_t len;
+
+	printk("\"Bad user\" message from 0x%04x\n", ctx->addr);
+
+	if (ctx->addr == bt_mesh_model_elem(model)->addr) {
+		printk("Ignoring message from self\n");
+		return;
+	}
+
+	len = MIN(buf->len, HELLO_MAX);
+	memcpy(str, buf->data, len);
+	str[len] = '\0';
+
+	strcat(str, " is misbehaving!");
+	board_show_text(str, false, K_SECONDS(3));
+
+	board_blink_leds();
+}
+
 static void vnd_heartbeat(struct bt_mesh_model *model,
 			  struct bt_mesh_msg_ctx *ctx,
 			  struct net_buf_simple *buf)
@@ -357,6 +384,7 @@ static void vnd_heartbeat(struct bt_mesh_model *model,
 static const struct bt_mesh_model_op vnd_ops[] = {
 	{ OP_VND_HELLO, 1, vnd_hello },
 	{ OP_VND_HEARTBEAT, 1, vnd_heartbeat },
+	{ OP_VND_BADUSER, 1, vnd_baduser },
 	BT_MESH_MODEL_OP_END,
 };
 
@@ -432,6 +460,33 @@ void mesh_send_hello(void)
 	k_work_submit(&hello_work);
 }
 
+static void send_baduser(struct k_work *work)
+{
+	NET_BUF_SIMPLE_DEFINE(msg, 3 + HELLO_MAX + 4);
+	struct bt_mesh_msg_ctx ctx = {
+		.net_idx = NET_IDX,
+		.app_idx = APP_IDX,
+		.addr = GROUP_ADDR,
+		.send_ttl = DEFAULT_TTL,
+	};
+	const char *name = bt_get_name();
+
+	bt_mesh_model_msg_init(&msg, OP_VND_BADUSER);
+	net_buf_simple_add_mem(&msg, name,
+			       MIN(HELLO_MAX, first_name_len(name)));
+
+	if (bt_mesh_model_send(&vnd_models[0], &ctx, &msg, NULL, NULL) == 0) {
+		board_show_text("Bad user!", false, K_SECONDS(2));
+	} else {
+		board_show_text("Sending Failed!", false, K_SECONDS(2));
+	}
+}
+
+void mesh_send_baduser(void)
+{
+	k_work_submit(&baduser_work);
+}
+
 static int provision_and_configure(void)
 {
 	static const u8_t net_key[16] = {
@@ -545,6 +600,7 @@ int mesh_init(void)
 	};
 
 	k_work_init(&hello_work, send_hello);
+	k_work_init(&baduser_work, send_baduser);
 	k_work_init(&mesh_start_work, start_mesh);
 
 	return bt_mesh_init(&prov, &comp);

samples/boards/reel_board/mesh_badge/src/mesh.h

@@ -34,6 +34,7 @@ struct led_onoff_state {
 };
 
 void mesh_send_hello(void);
+void mesh_send_baduser(void);
 
 u16_t mesh_get_addr(void);
 bool mesh_is_initialized(void);

samples/boards/reel_board/mesh_badge/src/reel_board.c

@@ -480,7 +480,27 @@ static void button_interrupt(struct device *dev, struct gpio_callback *cb,
 		return;
 	case SCREEN_MAIN:
 		if (pins & BIT(SW0_GPIO_PIN)) {
-			mesh_send_hello();
+			u32_t uptime = k_uptime_get_32();
+			static u32_t bad_count, press_ts;
+
+			if (uptime - press_ts < 500) {
+				bad_count++;
+			} else {
+				bad_count = 0;
+			}
+
+			press_ts = uptime;
+
+			if (bad_count) {
+				if (bad_count > 5) {
+					mesh_send_baduser();
+					bad_count = 0;
+				} else {
+					printk("Ignoring press\n");
+				}
+			} else {
+				mesh_send_hello();
+			}
 		}
 		return;
 	default: