drivers: wifi: esp: rework +CIPRECVDATA handling

Current on_cmd_ciprecvdata handler is a bit overwhelming to follow.

Add a cmd_ciprecvdata_parse() helper, which is responsible only for
parsing received metadata (message offset and length), leaving socket
instance untouched.

Consume received payload later on, just after verifying that socket is
in valid state.

Signed-off-by: Marcin Niestroj <[email protected]>

Author: mniestroj

drivers/wifi/esp/esp_offload.c

@@ -401,65 +401,77 @@ static int esp_send(struct net_pkt *pkt,
 
 #define CIPRECVDATA_CMD_MIN_LEN (sizeof("+CIPRECVDATA,L:") - 1)
 #define CIPRECVDATA_CMD_MAX_LEN (sizeof("+CIPRECVDATA,LLLL:") - 1)
-MODEM_CMD_DIRECT_DEFINE(on_cmd_ciprecvdata)
-{
-	char *endptr, cmd_buf[CIPRECVDATA_CMD_MAX_LEN + 1];
-	int data_offset, data_len, ret;
-	size_t match_len, frags_len;
-	struct esp_socket *sock;
-	struct esp_data *dev;
-	struct net_pkt *pkt;
 
-	dev = CONTAINER_OF(data, struct esp_data, cmd_handler_data);
-
-	sock = dev->rx_sock;
+static int cmd_ciprecvdata_parse(struct esp_socket *sock,
+				 struct net_buf *buf, uint16_t len,
+				 int *data_offset, int *data_len)
+{
+	char cmd_buf[CIPRECVDATA_CMD_MAX_LEN + 1];
+	char *endptr;
+	size_t frags_len;
+	size_t match_len;
 
-	frags_len = net_buf_frags_len(data->rx_buf);
+	frags_len = net_buf_frags_len(buf);
 	if (frags_len < CIPRECVDATA_CMD_MIN_LEN) {
-		ret = -EAGAIN;
-		goto out;
+		return -EAGAIN;
 	}
 
 	match_len = net_buf_linearize(cmd_buf, CIPRECVDATA_CMD_MAX_LEN,
-				      data->rx_buf, 0, CIPRECVDATA_CMD_MAX_LEN);
-
+				      buf, 0, CIPRECVDATA_CMD_MAX_LEN);
 	cmd_buf[match_len] = 0;
 
-	data_len = strtol(&cmd_buf[len], &endptr, 10);
+	*data_len = strtol(&cmd_buf[len], &endptr, 10);
 	if (endptr == &cmd_buf[len] ||
 	    (*endptr == 0 && match_len >= CIPRECVDATA_CMD_MAX_LEN) ||
-	    data_len > sock->bytes_avail) {
+	    *data_len > sock->bytes_avail) {
 		LOG_ERR("Invalid cmd: %s", log_strdup(cmd_buf));
-		ret = len;
-		goto out;
+		return -EBADMSG;
 	} else if (*endptr == 0) {
-		ret = -EAGAIN;
-		goto out;
+		return -EAGAIN;
 	} else if (*endptr != _CIPRECVDATA_END) {
 		LOG_ERR("Invalid end of cmd: 0x%02x != 0x%02x", *endptr,
 			_CIPRECVDATA_END);
-		ret = len;
-		goto out;
+		return -EBADMSG;
 	}
 
-	*endptr = 0;
-
 	/* data_offset is the offset to where the actual data starts */
-	data_offset = strlen(cmd_buf) + 1;
+	*data_offset = (endptr - cmd_buf) + 1;
 
 	/* FIXME: Inefficient way of waiting for data */
-	if (data_offset + data_len > frags_len) {
-		ret = -EAGAIN;
-		goto out;
+	if (*data_offset + *data_len > frags_len) {
+		return -EAGAIN;
+	}
+
+	*endptr = 0;
+
+	return 0;
+}
+
+MODEM_CMD_DIRECT_DEFINE(on_cmd_ciprecvdata)
+{
+	struct esp_data *dev = CONTAINER_OF(data, struct esp_data,
+					    cmd_handler_data);
+	struct esp_socket *sock = dev->rx_sock;
+	int data_offset, data_len;
+	struct net_pkt *pkt;
+	int err;
+
+	err = cmd_ciprecvdata_parse(sock, data->rx_buf, len, &data_offset,
+				    &data_len);
+	if (err) {
+		if (err == -EAGAIN) {
+			return -EAGAIN;
+		}
+
+		return err;
 	}
 
 	sock->bytes_avail -= data_len;
-	ret = data_offset + data_len;
 
 	if ((sock->flags & (ESP_SOCK_CONNECTED | ESP_SOCK_CLOSE_PENDING)) !=
 							ESP_SOCK_CONNECTED) {
 		LOG_DBG("Received data on closed link %d", sock->link_id);
-		goto out;
+		return data_offset + data_len;
 	}
 
 	pkt = esp_prepare_pkt(dev, data->rx_buf, data_offset, data_len);
@@ -476,8 +488,7 @@ MODEM_CMD_DIRECT_DEFINE(on_cmd_ciprecvdata)
 submit_work:
 	k_work_submit_to_queue(&dev->workq, &sock->recv_work);
 
-out:
-	return ret;
+	return data_offset + data_len;
 }
 
 static void esp_recvdata_work(struct k_work *work)