ESP-MESH Programming Guide

This is a programming guide for ESP-MESH, including the API reference and coding examples. This guide is split into the following parts:

  1. ESP-MESH Programming Model
  2. Writing an ESP-MESH Application
  3. Application Examples
  4. API Reference

For documentation regarding the ESP-MESH protocol, please see the ESP-MESH API Guide.

ESP-MESH Programming Model

Software Stack

The ESP-MESH software stack is built atop the Wi-Fi Driver/FreeRTOS and may use the LwIP Stack in some instances (i.e. the root node). The following diagram illustrates the ESP-MESH software stack.

ESP-MESH Software Stack

ESP-MESH Software Stack

System Events

An application interfaces with ESP-MESH via ESP-MESH Events. Since ESP-MESH is built atop the Wi-Fi stack, it is also possible for the application to interface with the Wi-Fi driver via the Wi-Fi Event Task. The following diagram illustrates the interfaces for the various System Events in an ESP-MESH application.

ESP-MESH System Events Delivery

ESP-MESH System Events Delivery

The mesh_event_id_t defines all possible ESP-MESH system events and can indicate events such as the connection/disconnection of parent/child. Before ESP-MESH system events can be used, the application must register a Mesh Event Callback via esp_mesh_set_config(). The callback is used to receive events from the ESP-MESH stack as well as the LwIP Stack and should contain handlers for each event relevant to the application.

Typical use cases of system events include using events such as MESH_EVENT_PARENT_CONNECTED and MESH_EVENT_CHILD_CONNECTED to indicate when a node can begin transmitting data upstream and downstream respectively. Likewise, MESH_EVENT_ROOT_GOT_IP and MESH_EVENT_ROOT_LOST_IP can be used to indicate when the root node can and cannot transmit data to the external IP network.

Warning

When using ESP-MESH under self-organized mode, users must ensure that no calls to Wi-Fi API are made. This is due to the fact that the self-organizing mode will internally make Wi-Fi API calls to connect/disconnect/scan etc. Any Wi-Fi calls from the application (including calls from callbacks and handlers of Wi-Fi events) may interfere with ESP-MESH’s self-organizing behavior. Therefore, user’s should not call Wi-Fi APIs after esp_mesh_start() is called, and before esp_mesh_stop() is called.

LwIP & ESP-MESH

The application can access the ESP-MESH stack directly without having to go through the LwIP stack. The LwIP stack is only required by the root node to transmit/receive data to/from an external IP network. However, since every node can potentially become the root node (due to automatic root node selection), each node must still initialize the LwIP stack.

Each node is required to initialize LwIP by calling tcpip_adapter_init(). In order to prevent non-root node access to LwIP, the application should stop the following services after LwIP initialization:

  • DHCP server service on the softAP interface.
  • DHCP client service on the station interface.

The following code snippet demonstrates how to initialize LwIP for ESP-MESH applications.

/*  tcpip initialization */
tcpip_adapter_init();
/*
 * for mesh
 * stop DHCP server on softAP interface by default
 * stop DHCP client on station interface by default
 */
ESP_ERROR_CHECK(tcpip_adapter_dhcps_stop(TCPIP_ADAPTER_IF_AP));
ESP_ERROR_CHECK(tcpip_adapter_dhcpc_stop(TCPIP_ADAPTER_IF_STA));
/* do not specify system event callback, use NULL instead. */
ESP_ERROR_CHECK(esp_event_loop_init(NULL, NULL));

Note

ESP-MESH requires a root node to be connected with a router. Therefore, in the event that a node becomes the root, the corresponding handler must start the DHCP client service and immediately obtain an IP address. Doing so will allow other nodes to begin transmitting/receiving packets to/from the external IP network. However, this step is unnecessary if static IP settings are used.

Writing an ESP-MESH Application

The prerequisites for starting ESP-MESH is to initialize LwIP and Wi-Fi, The following code snippet demonstrates the necessary prerequisite steps before ESP-MESH itself can be initialized.

tcpip_adapter_init();
/*
 * for mesh
 * stop DHCP server on softAP interface by default
 * stop DHCP client on station interface by default
 */
ESP_ERROR_CHECK(tcpip_adapter_dhcps_stop(TCPIP_ADAPTER_IF_AP));
ESP_ERROR_CHECK(tcpip_adapter_dhcpc_stop(TCPIP_ADAPTER_IF_STA));
/* do not specify system event callback, use NULL instead. */
ESP_ERROR_CHECK(esp_event_loop_init(NULL, NULL));

/*  Wi-Fi initialization */
wifi_init_config_t config = WIFI_INIT_CONFIG_DEFAULT();
ESP_ERROR_CHECK(esp_wifi_init(&config));
ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_FLASH));
ESP_ERROR_CHECK(esp_wifi_start());

After initializing LwIP and Wi-Fi, the process of getting an ESP-MESH network up and running can be summarized into the following three steps:

  1. Initialize Mesh
  2. Configuring an ESP-MESH Network
  3. Start Mesh

Initialize Mesh

The following code snippet demonstrates how to initialize ESP-MESH

/*  mesh initialization */
ESP_ERROR_CHECK(esp_mesh_init());

Configuring an ESP-MESH Network

ESP-MESH is configured via esp_mesh_set_config() which receives its arguments using the mesh_cfg_t structure. The structure contains the following parameters used to configure ESP-MESH:

Parameter Description
Channel Range from 1 to 14
Event Callback Callback for Mesh Events, see mesh_event_cb_t
Mesh ID ID of ESP-MESH Network, see mesh_addr_t
Router Router Configuration, see mesh_router_t
Mesh AP Mesh AP Configuration, see mesh_ap_cfg_t
Crypto Functions Crypto Functions for Mesh IE, see mesh_crypto_funcs_t

The following code snippet demonstrates how to configure ESP-MESH.

/* Enable the Mesh IE encryption by default */
mesh_cfg_t cfg = MESH_INIT_CONFIG_DEFAULT();
/* mesh ID */
memcpy((uint8_t *) &cfg.mesh_id, MESH_ID, 6);
/* mesh event callback */
cfg.event_cb = &mesh_event_handler;
/* channel (must match the router's channel) */
cfg.channel = CONFIG_MESH_CHANNEL;
/* router */
cfg.router.ssid_len = strlen(CONFIG_MESH_ROUTER_SSID);
memcpy((uint8_t *) &cfg.router.ssid, CONFIG_MESH_ROUTER_SSID, cfg.router.ssid_len);
memcpy((uint8_t *) &cfg.router.password, CONFIG_MESH_ROUTER_PASSWD,
       strlen(CONFIG_MESH_ROUTER_PASSWD));
/* mesh softAP */
cfg.mesh_ap.max_connection = CONFIG_MESH_AP_CONNECTIONS;
memcpy((uint8_t *) &cfg.mesh_ap.password, CONFIG_MESH_AP_PASSWD,
       strlen(CONFIG_MESH_AP_PASSWD));
ESP_ERROR_CHECK(esp_mesh_set_config(&cfg));

Start Mesh

The following code snippet demonstrates how to start ESP-MESH.

/* mesh start */
ESP_ERROR_CHECK(esp_mesh_start());

After starting ESP-MESH, the application should check for ESP-MESH events to determine when it has connected to the network. After connecting, the application can start transmitting and receiving packets over the ESP-MESH network using esp_mesh_send() and esp_mesh_recv().

Application Examples

ESP-IDF contains these ESP-MESH example projects:

The Internal Communication Example demonstrates how to setup a ESP-MESH network and have the root node send a data packet to every node within the network.

The Manual Networking Example demonstrates how to use ESP-MESH without the self-organizing features. This example shows how to program a node to manually scan for a list of potential parent nodes and select a parent node based on custom criteria.

API Reference

Functions

esp_err_t esp_mesh_init(void)

Mesh initialization.

  • Check whether Wi-Fi is started.
  • Initialize mesh global variables with default values.

Attention
This API shall be called after Wi-Fi is started.
Return
  • ESP_OK
  • ESP_FAIL

esp_err_t esp_mesh_deinit(void)

Mesh de-initialization.

  • Release resources and stop the mesh

Return
  • ESP_OK
  • ESP_FAIL

esp_err_t esp_mesh_start(void)

Start mesh.

  • Initialize mesh IE.
  • Start mesh network management service.
  • Create TX and RX queues according to the configuration.
  • Register mesh packets receive callback.

Attention
　　This API shall be called after mesh initialization and configuration.
Return
  • ESP_OK
  • ESP_FAIL
  • ESP_ERR_MESH_NOT_INIT
  • ESP_ERR_MESH_NOT_CONFIG
  • ESP_ERR_MESH_NO_MEMORY

esp_err_t esp_mesh_stop(void)

Stop mesh.

  • Deinitialize mesh IE.
  • Disconnect with current parent.
  • Disassociate all currently associated children.
  • Stop mesh network management service.
  • Unregister mesh packets receive callback.
  • Delete TX and RX queues.
  • Release resources.
  • Restore Wi-Fi softAP to default settings if Wi-Fi dual mode is enabled.

Return
  • ESP_OK
  • ESP_FAIL

esp_err_t esp_mesh_send(const mesh_addr_t *to, const mesh_data_t *data, int flag, const mesh_opt_t opt[], int opt_count)

Send a packet over the mesh network.

  • Send a packet to any device in the mesh network.
  • Send a packet to external IP network.

Attention
This API is not reentrant.
Return
  • ESP_OK
  • ESP_FAIL
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_START
  • ESP_ERR_MESH_DISCONNECTED
  • ESP_ERR_MESH_OPT_UNKNOWN
  • ESP_ERR_MESH_EXCEED_MTU
  • ESP_ERR_MESH_NO_MEMORY
  • ESP_ERR_MESH_TIMEOUT
  • ESP_ERR_MESH_QUEUE_FULL
  • ESP_ERR_MESH_NO_ROUTE_FOUND
  • ESP_ERR_MESH_DISCARD
Parameters
  • to: the address of the final destination of the packet
    • If the packet is to the root, set this parameter to NULL.
    • If the packet is to an external IP network, set this parameter to the IPv4:PORT combination. This packet will be delivered to the root firstly, then the root will forward this packet to the final IP server address.
  • data: pointer to a sending mesh packet
    • Field size should not exceed MESH_MPS. Note that the size of one mesh packet should not exceed MESH_MTU.
    • Field proto should be set to data protocol in use (default is MESH_PROTO_BIN for binary).
    • Field tos should be set to transmission tos (type of service) in use (default is MESH_TOS_P2P for point-to-point reliable).
  • flag: bitmap for data sent
    • Speed up the route search
      • If the packet is to the root and “to” parameter is NULL, set this parameter to 0.
      • If the packet is to an internal device, MESH_DATA_P2P should be set.
      • If the packet is to the root (“to” parameter isn’t NULL) or to external IP network, MESH_DATA_TODS should be set.
      • If the packet is from the root to an internal device, MESH_DATA_FROMDS should be set.
    • Specify whether this API is block or non-block, block by default
      • If needs non-block, MESH_DATA_NONBLOCK should be set.
    • In the situation of the root change, MESH_DATA_DROP identifies this packet can be dropped by the new root for upstream data to external IP network, we try our best to avoid data loss caused by the root change, but there is a risk that the new root is running out of memory because most of memory is occupied by the pending data which isn’t read out in time by esp_mesh_recv_toDS().

      Generally, we suggest esp_mesh_recv_toDS() is called after a connection with IP network is created. Thus data outgoing to external IP network via socket is just from reading esp_mesh_recv_toDS() which avoids unnecessary memory copy.

  • opt: options
    • In case of sending a packet to a certain group, MESH_OPT_SEND_GROUP is a good choice. In this option, the value field should be set to the target receiver addresses in this group.
    • Root sends a packet to an internal device, this packet is from external IP network in case the receiver device responds this packet, MESH_OPT_RECV_DS_ADDR is required to attach the target DS address.
  • opt_count: option count
    • Currently, this API only takes one option, so opt_count is only supported to be 1.

esp_err_t esp_mesh_recv(mesh_addr_t *from, mesh_data_t *data, int timeout_ms, int *flag, mesh_opt_t opt[], int opt_count)

Receive a packet targeted to self over the mesh network.

flag could be MESH_DATA_FROMDS or MESH_DATA_TODS.

Attention
Mesh RX queue should be checked regularly to avoid running out of memory.
  • Use esp_mesh_get_rx_pending() to check the number of packets available in the queue waiting to be received by applications.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_START
  • ESP_ERR_MESH_TIMEOUT
  • ESP_ERR_MESH_DISCARD
Parameters
  • from: the address of the original source of the packet
  • data: pointer to the received mesh packet
    • Field proto is the data protocol in use. Should follow it to parse the received data.
    • Field tos is the transmission tos (type of service) in use.
  • timeout_ms: wait time if a packet isn’t immediately available (0:no wait, portMAX_DELAY:wait forever)
  • flag: bitmap for data received
    • MESH_DATA_FROMDS represents data from external IP network
    • MESH_DATA_TODS represents data directed upward within the mesh network
Parameters
  • opt: options desired to receive
    • MESH_OPT_RECV_DS_ADDR attaches the DS address
  • opt_count: option count desired to receive
    • Currently, this API only takes one option, so opt_count is only supported to be 1.

esp_err_t esp_mesh_recv_toDS(mesh_addr_t *from, mesh_addr_t *to, mesh_data_t *data, int timeout_ms, int *flag, mesh_opt_t opt[], int opt_count)

Receive a packet targeted to external IP network.

  • Root uses this API to receive packets destined to external IP network
  • Root forwards the received packets to the final destination via socket.
  • If no socket connection is ready to send out the received packets and this esp_mesh_recv_toDS() hasn’t been called by applications, packets from the whole mesh network will be pending in toDS queue.

Use esp_mesh_get_rx_pending() to check the number of packets available in the queue waiting to be received by applications in case of running out of memory in the root.

Using esp_mesh_set_xon_qsize() users may configure the RX queue size, default:32. If this size is too large, and esp_mesh_recv_toDS() isn’t called in time, there is a risk that a great deal of memory is occupied by the pending packets. If this size is too small, it will impact the efficiency on upstream. How to decide this value depends on the specific application scenarios.

flag could be MESH_DATA_TODS.

Attention
This API is only called by the root.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_START
  • ESP_ERR_MESH_TIMEOUT
  • ESP_ERR_MESH_DISCARD
Parameters
  • from: the address of the original source of the packet
  • to: the address contains remote IP address and port (IPv4:PORT)
  • data: pointer to the received packet
    • Contain the protocol and applications should follow it to parse the data.
  • timeout_ms: wait time if a packet isn’t immediately available (0:no wait, portMAX_DELAY:wait forever)
  • flag: bitmap for data received
    • MESH_DATA_TODS represents the received data target to external IP network. Root shall forward this data to external IP network via the association with router.
Parameters
  • opt: options desired to receive
  • opt_count: option count desired to receive

esp_err_t esp_mesh_set_config(const mesh_cfg_t *config)

Set mesh stack configuration.

  • Use MESH_INIT_CONFIG_DEFAULT() to initialize the default values, mesh IE is encrypted by default.
  • Mesh network is established on a fixed channel (1-14).
  • Mesh event callback is mandatory.
  • Mesh ID is an identifier of an MBSS. Nodes with the same mesh ID can communicate with each other.
  • Regarding to the router configuration, if the router is hidden, BSSID field is mandatory.

If BSSID field isn’t set and there exists more than one router with same SSID, there is a risk that more roots than one connected with different BSSID will appear. It means more than one mesh network is established with the same mesh ID.

Root conflict function could eliminate redundant roots connected with the same BSSID, but couldn’t handle roots connected with different BSSID. Because users might have such requirements of setting up routers with same SSID for the future replacement. But in that case, if the above situations happen, please make sure applications implement forward functions on the root to guarantee devices in different mesh networks can communicate with each other. max_connection of mesh softAP is limited by the max number of Wi-Fi softAP supported (max:10).

Attention
This API shall be called before mesh is started after mesh is initialized.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_ALLOWED
Parameters
  • config: pointer to mesh stack configuration

esp_err_t esp_mesh_get_config(mesh_cfg_t *config)

Get mesh stack configuration.

Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • config: pointer to mesh stack configuration

esp_err_t esp_mesh_set_router(const mesh_router_t *router)

Get router configuration.

Attention
This API is used to dynamically modify the router configuration after mesh is configured.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • router: pointer to router configuration

esp_err_t esp_mesh_get_router(mesh_router_t *router)

Get router configuration.

Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • router: pointer to router configuration

esp_err_t esp_mesh_set_id(const mesh_addr_t *id)

Set mesh network ID.

Attention
This API is used to dynamically modify the mesh network ID.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT: invalid argument
Parameters
  • id: pointer to mesh network ID

esp_err_t esp_mesh_get_id(mesh_addr_t *id)

Get mesh network ID.

Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • id: pointer to mesh network ID

esp_err_t esp_mesh_set_type(mesh_type_t type)

Designate device type over the mesh network.

  • MESH_ROOT: designates the root node for a mesh network
  • MESH_LEAF: designates a device as a standalone Wi-Fi station

Return
  • ESP_OK
  • ESP_ERR_MESH_NOT_ALLOWED
Parameters
  • type: device type

mesh_type_t esp_mesh_get_type(void)

Get device type over mesh network.

Attention
This API shall be called after having received the event MESH_EVENT_PARENT_CONNECTED.
Return
mesh type

esp_err_t esp_mesh_set_max_layer(int max_layer)

Set network max layer value (max:25, default:25)

  • Network max layer limits the max hop count.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_ALLOWED
Parameters
  • max_layer: max layer value

int esp_mesh_get_max_layer(void)

Get max layer value.

Return
max layer value

esp_err_t esp_mesh_set_ap_password(const uint8_t *pwd, int len)

Set mesh softAP password.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_ALLOWED
Parameters
  • pwd: pointer to the password
  • len: password length

esp_err_t esp_mesh_set_ap_authmode(wifi_auth_mode_t authmode)

Set mesh softAP authentication mode.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
  • ESP_ERR_MESH_NOT_ALLOWED
Parameters
  • authmode: authentication mode

wifi_auth_mode_t esp_mesh_get_ap_authmode(void)

Get mesh softAP authentication mode.

Return
authentication mode

esp_err_t esp_mesh_set_ap_connections(int connections)

Set mesh softAP max connection value.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • connections: the number of max connections

int esp_mesh_get_ap_connections(void)

Get mesh softAP max connection configuration.

Return
the number of max connections

int esp_mesh_get_layer(void)

Get current layer value over the mesh network.

Attention
This API shall be called after having received the event MESH_EVENT_PARENT_CONNECTED.
Return
layer value

esp_err_t esp_mesh_get_parent_bssid(mesh_addr_t *bssid)

Get the parent BSSID.

Attention
This API shall be called after having received the event MESH_EVENT_PARENT_CONNECTED.
Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • bssid: pointer to parent BSSID

bool esp_mesh_is_root(void)

Return whether the device is the root node of the network.

Return
true/false

esp_err_t esp_mesh_set_self_organized(bool enable, bool select_parent)

Enable/disable self-organized networking.

  • Self-organized networking has three main functions: select the root node; find a preferred parent; initiate reconnection if a disconnection is detected.
  • Self-organized networking is enabled by default.
  • If self-organized is disabled, users should set a parent for the device via esp_mesh_set_parent().

Attention
This API is used to dynamically modify whether to enable the self organizing.
Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • enable: enable or disable self-organized networking
  • select_parent: Only valid when self-organized networking is enabled.
    • if select_parent is set to true, the root will give up its mesh root status and search for a new parent like other non-root devices.

bool esp_mesh_get_self_organized(void)

Return whether enable self-organized networking or not.

Return
true/false

esp_err_t esp_mesh_waive_root(const mesh_vote_t *vote, int reason)

Cause the root device to give up (waive) its mesh root status.

  • A device is elected root primarily based on RSSI from the external router.
  • If external router conditions change, users can call this API to perform a root switch.
  • In this API, users could specify a desired root address to replace itself or specify an attempts value to ask current root to initiate a new round of voting. During the voting, a better root candidate would be expected to find to replace the current one.
  • If no desired root candidate, the vote will try a specified number of attempts (at least 15). If no better root candidate is found, keep the current one. If a better candidate is found, the new better one will send a root switch request to the current root, current root will respond with a root switch acknowledgment.
  • After that, the new candidate will connect to the router to be a new root, the previous root will disconnect with the router and choose another parent instead.

Root switch is completed with minimal disruption to the whole mesh network.

Attention
This API is only called by the root.
Return
  • ESP_OK
  • ESP_ERR_MESH_QUEUE_FULL
  • ESP_ERR_MESH_DISCARD
  • ESP_FAIL
Parameters
  • vote: vote configuration
    • If this parameter is set NULL, the vote will perform the default 15 times.
    • Field percentage threshold is 0.9 by default.
    • Field is_rc_specified shall be false.
    • Field attempts shall be at least 15 times.
  • reason: only accept MESH_VOTE_REASON_ROOT_INITIATED for now

esp_err_t esp_mesh_set_vote_percentage(float percentage)

Set vote percentage threshold for approval of being a root.

  • During the networking, only obtaining vote percentage reaches this threshold, the device could be a root.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • percentage: vote percentage threshold

float esp_mesh_get_vote_percentage(void)

Get vote percentage threshold for approval of being a root.

Return
percentage threshold

esp_err_t esp_mesh_set_ap_assoc_expire(int seconds)

Set mesh softAP associate expired time (default:10 seconds)

  • If mesh softAP hasn’t received any data from an associated child within this time, mesh softAP will take this child inactive and disassociate it.
  • If mesh softAP is encrypted, this value should be set a greater value, such as 30 seconds.

Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • seconds: the expired time

int esp_mesh_get_ap_assoc_expire(void)

Get mesh softAP associate expired time.

Return
seconds

int esp_mesh_get_total_node_num(void)

Get total number of devices in current network (including the root)

Attention
The returned value might be incorrect when the network is changing.
Return
total number of devices (including the root)

int esp_mesh_get_routing_table_size(void)

Get the number of devices in this device’s sub-network (including self)

Return
the number of devices over this device’s sub-network (including self)

esp_err_t esp_mesh_get_routing_table(mesh_addr_t *mac, int len, int *size)

Get routing table of this device’s sub-network (including itself)

Return
  • ESP_OK
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • mac: pointer to routing table
  • len: routing table size(in bytes)
  • size: pointer to the number of devices in routing table (including itself)

esp_err_t esp_mesh_post_toDS_state(bool reachable)

Post the toDS state to the mesh stack.

Attention
This API is only for the root.
Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • reachable: this state represents whether the root is able to access external IP network

esp_err_t esp_mesh_get_tx_pending(mesh_tx_pending_t *pending)

Return the number of packets pending in the queue waiting to be sent by the mesh stack.

Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • pending: pointer to the TX pending

esp_err_t esp_mesh_get_rx_pending(mesh_rx_pending_t *pending)

Return the number of packets available in the queue waiting to be received by applications.

Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • pending: pointer to the RX pending

int esp_mesh_available_txupQ_num(const mesh_addr_t *addr, uint32_t *xseqno_in)

Return the number of packets could be accepted from the specified address.

Return
the number of upQ for a certain address
Parameters
  • addr: self address or an associate children address
  • xseqno_in: sequence number of the last received packet from the specified address

esp_err_t esp_mesh_set_xon_qsize(int qsize)

Set the number of queue.

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_FAIL
Parameters
  • qsize: default:32 (min:16)

int esp_mesh_get_xon_qsize(void)

Get queue size.

Return
the number of queue

esp_err_t esp_mesh_allow_root_conflicts(bool allowed)

Set whether allow more than one root existing in one network.

Return
  • ESP_OK
  • ESP_WIFI_ERR_NOT_INIT
  • ESP_WIFI_ERR_NOT_START
Parameters
  • allowed: allow or not

bool esp_mesh_is_root_conflicts_allowed(void)

Check whether allow more than one root to exist in one network.

Return
true/false

esp_err_t esp_mesh_set_group_id(const mesh_addr_t *addr, int num)

Set group ID addresses.

Return
  • ESP_OK
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • addr: pointer to new group ID addresses
  • num: the number of group ID addresses

esp_err_t esp_mesh_delete_group_id(const mesh_addr_t *addr, int num)

Delete group ID addresses.

Return
  • ESP_OK
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • addr: pointer to deleted group ID address
  • num: the number of group ID addresses

int esp_mesh_get_group_num(void)

Get the number of group ID addresses.

Return
the number of group ID addresses

esp_err_t esp_mesh_get_group_list(mesh_addr_t *addr, int num)

Get group ID addresses.

Return
  • ESP_OK
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • addr: pointer to group ID addresses
  • num: the number of group ID addresses

bool esp_mesh_is_my_group(const mesh_addr_t *addr)

Check whether the specified group address is my group.

Return
true/false

esp_err_t esp_mesh_set_capacity_num(int num)

Set mesh network capacity (max:1000, default:300)

Attention
This API shall be called before mesh is started.
Return
  • ESP_OK
  • ESP_ERR_MESH_NOT_ALLOWED
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • num: mesh network capacity

int esp_mesh_get_capacity_num(void)

Get mesh network capacity.

Return
mesh network capacity

esp_err_t esp_mesh_set_ie_crypto_funcs(const mesh_crypto_funcs_t *crypto_funcs)

Set mesh IE crypto functions.

Attention
This API can be called at any time after mesh is initialized.
Return
  • ESP_OK
Parameters
  • crypto_funcs: crypto functions for mesh IE
    • If crypto_funcs is set to NULL, mesh IE is no longer encrypted.

esp_err_t esp_mesh_set_ie_crypto_key(const char *key, int len)

Set mesh IE crypto key.

Attention
This API can be called at any time after mesh is initialized.
Return
  • ESP_OK
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • key: ASCII crypto key
  • len: length in bytes, range:8~64

esp_err_t esp_mesh_get_ie_crypto_key(char *key, int len)

Get mesh IE crypto key.

Return
  • ESP_OK
  • ESP_MESH_ERR_ARGUMENT
Parameters
  • key: ASCII crypto key
  • len: length in bytes, range:8~64

esp_err_t esp_mesh_set_root_healing_delay(int delay_ms)

Set delay time before starting root healing.

Return
  • ESP_OK
Parameters
  • delay_ms: delay time in milliseconds

int esp_mesh_get_root_healing_delay(void)

Get delay time before network starts root healing.

Return
delay time in milliseconds

esp_err_t esp_mesh_set_event_cb(const mesh_event_cb_t event_cb)

Set mesh event callback.

Return
  • ESP_OK
Parameters
  • event_cb: mesh event call back

esp_err_t esp_mesh_fix_root(bool enable)

Enable network Fixed Root Setting.

  • Enabling fixed root disables automatic election of the root node via voting.
  • All devices in the network shall use the same Fixed Root Setting (enabled or disabled).
  • If Fixed Root is enabled, users should make sure a root node is designated for the network.

Return
  • ESP_OK
Parameters
  • enable: enable or not

bool esp_mesh_is_root_fixed(void)

Check whether network Fixed Root Setting is enabled.

  • Enable/disable network Fixed Root Setting by API esp_mesh_fix_root().
  • Network Fixed Root Setting also changes with the “flag” value in parent networking IE.

Return
true/false

esp_err_t esp_mesh_set_parent(const wifi_config_t *parent, const mesh_addr_t *parent_mesh_id, mesh_type_t my_type, int my_layer)

Set a specified parent for the device.

Attention
This API can be called at any time after mesh is configured.
Return
  • ESP_OK
  • ESP_ERR_ARGUMENT
  • ESP_ERR_MESH_NOT_CONFIG
Parameters
  • parent: parent configuration, the SSID and the channel of the parent are mandatory.
    • If the BSSID is set, make sure that the SSID and BSSID represent the same parent, otherwise the device will never find this specified parent.
  • parent_mesh_id: parent mesh ID,
    • If this value is not set, the original mesh ID is used.
  • my_type: mesh type
    • If the parent set for the device is the same as the router in the network configuration, then my_type shall set MESH_ROOT and my_layer shall set MESH_ROOT_LAYER.
  • my_layer: mesh layer
    • my_layer of the device may change after joining the network.
    • If my_type is set MESH_NODE, my_layer shall be greater than MESH_ROOT_LAYER.
    • If my_type is set MESH_LEAF, the device becomes a standalone Wi-Fi station and no longer has the ability to extend the network.

esp_err_t esp_mesh_scan_get_ap_ie_len(int *len)

Get mesh networking IE length of one AP.

Return
  • ESP_OK
  • ESP_ERR_WIFI_NOT_INIT
  • ESP_ERR_WIFI_ARG
  • ESP_ERR_WIFI_FAIL
Parameters
  • len: mesh networking IE length

esp_err_t esp_mesh_scan_get_ap_record(wifi_ap_record_t *ap_record, void *buffer)

Get AP record.

Attention
Different from esp_wifi_scan_get_ap_records(), this API only gets one of APs scanned each time. See “manual_networking” example.
Return
  • ESP_OK
  • ESP_ERR_WIFI_NOT_INIT
  • ESP_ERR_WIFI_ARG
  • ESP_ERR_WIFI_FAIL
Parameters
  • ap_record: pointer to one AP record
  • buffer: pointer to the mesh networking IE of this AP

esp_err_t esp_mesh_flush_upstream_packets(void)

Flush upstream packets pending in to_parent queue and to_parent_p2p queue.

Return
  • ESP_OK

esp_err_t esp_mesh_get_subnet_nodes_num(const mesh_addr_t *child_mac, int *nodes_num)

Get the number of nodes in the subnet of a specific child.

Return
  • ESP_OK
  • ESP_ERR_MESH_NOT_START
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • child_mac: an associated child address of this device
  • nodes_num: pointer to the number of nodes in the subnet of a specific child

esp_err_t esp_mesh_get_subnet_nodes_list(const mesh_addr_t *child_mac, mesh_addr_t *nodes, int nodes_num)

Get nodes in the subnet of a specific child.

Return
  • ESP_OK
  • ESP_ERR_MESH_NOT_START
  • ESP_ERR_MESH_ARGUMENT
Parameters
  • child_mac: an associated child address of this device
  • nodes: pointer to nodes in the subnet of a specific child
  • nodes_num: the number of nodes in the subnet of a specific child

esp_err_t esp_mesh_disconnect(void)

Disconnect from current parent.

Return
  • ESP_OK

esp_err_t esp_mesh_connect(void)

Connect to current parent.

Return
  • ESP_OK

esp_err_t esp_mesh_flush_scan_result(void)

Flush scan result.

Return
  • ESP_OK

esp_err_t esp_mesh_switch_channel(const uint8_t *new_bssid, int csa_newchan, int csa_count)

Cause the root device to add Channel Switch Announcement Element (CSA IE) to beacon.

  • Set the new channel
  • Set how many beacons with CSA IE will be sent before changing a new channel
  • Enable the channel switch function

Attention
This API is only called by the root.
Return
  • ESP_OK
Parameters
  • new_bssid: the new router BSSID if the router changes
  • csa_newchan: the new channel number to which the whole network is moving
  • csa_count: channel switch period(beacon count), unit is based on beacon interval of its softAP, the default value is 15.

esp_err_t esp_mesh_get_router_bssid(uint8_t *router_bssid)

Get the router BSSID.

Return
  • ESP_OK
  • ESP_ERR_WIFI_NOT_INIT
  • ESP_ERR_WIFI_ARG
Parameters
  • router_bssid: pointer to the router BSSID

int64_t esp_mesh_get_tsf_time(void)

Get the TSF time.

Return
the TSF time

Unions

union mesh_addr_t
#include <esp_mesh.h>

Mesh address.

Public Members

uint8_t addr[6]

mac address

mip_t mip

mip address

union mesh_event_info_t
#include <esp_mesh.h>

Mesh event information.

Public Members

mesh_event_channel_switch_t channel_switch

channel switch

mesh_event_child_connected_t child_connected

child connected

mesh_event_child_disconnected_t child_disconnected

child disconnected

mesh_event_routing_table_change_t routing_table

routing table change

mesh_event_connected_t connected

parent connected

mesh_event_disconnected_t disconnected

parent disconnected

mesh_event_no_parent_found_t no_parent

no parent found

mesh_event_layer_change_t layer_change

layer change

mesh_event_toDS_state_t toDS_state

toDS state, devices shall check this state firstly before trying to send packets to external IP network. This state indicates right now whether the root is capable of sending packets out. If not, devices had better to wait until this state changes to be MESH_TODS_REACHABLE.

mesh_event_vote_started_t vote_started

vote started

mesh_event_root_got_ip_t got_ip

root obtains IP address

mesh_event_root_address_t root_addr

root address

mesh_event_root_switch_req_t switch_req

root switch request

mesh_event_root_conflict_t root_conflict

other powerful root

mesh_event_root_fixed_t root_fixed

fixed root

mesh_event_scan_done_t scan_done

scan done

mesh_event_network_state_t network_state

network state, such as whether current mesh network has a root.

mesh_event_find_network_t find_network

network found that can join

mesh_event_router_switch_t router_switch

new router information

union mesh_rc_config_t
#include <esp_mesh.h>

Vote address configuration.

Public Members

int attempts

max vote attempts before a new root is elected automatically by mesh network. (min:15, 15 by default)

mesh_addr_t rc_addr

a new root address specified by users for API esp_mesh_waive_root()

Structures

struct mip_t

IP address and port.

Public Members

ip4_addr_t ip4

IP address

uint16_t port

port

struct mesh_event_channel_switch_t

Channel switch information.

Public Members

uint8_t channel

new channel

struct mesh_event_connected_t

Parent connected information.

Public Members

system_event_sta_connected_t connected

parent information, same as Wi-Fi event SYSTEM_EVENT_STA_CONNECTED does

uint8_t self_layer

layer

struct mesh_event_no_parent_found_t

No parent found information.

Public Members

int scan_times

scan times being through

struct mesh_event_layer_change_t

Layer change information.

Public Members

uint8_t new_layer

new layer

struct mesh_event_vote_started_t

vote started information

Public Members

int reason

vote reason, vote could be initiated by children or by the root itself

int attempts

max vote attempts before stopped

mesh_addr_t rc_addr

root address specified by users via API esp_mesh_waive_root()

struct mesh_event_find_network_t

find a mesh network that this device can join

Public Members

uint8_t channel

channel number of the new found network

uint8_t router_bssid[6]

router BSSID

struct mesh_event_root_switch_req_t

Root switch request information.

Public Members

int reason

root switch reason, generally root switch is initialized by users via API esp_mesh_waive_root()

mesh_addr_t rc_addr

the address of root switch requester

struct mesh_event_root_conflict_t

Other powerful root address.

Public Members

int8_t rssi

rssi with router

uint16_t capacity

the number of devices in current network

uint8_t addr[6]

other powerful root address

struct mesh_event_routing_table_change_t

Routing table change.

Public Members

uint16_t rt_size_new

the new value

uint16_t rt_size_change

the changed value

struct mesh_event_root_fixed_t

Root fixed.

Public Members

bool is_fixed

status

struct mesh_event_scan_done_t

Scan done　event information.

Public Members

uint8_t number

the number of APs scanned

struct mesh_event_network_state_t

Network state information.

Public Members

bool is_rootless

whether current mesh network has a root

struct mesh_event_t

Mesh event.

Public Members

mesh_event_id_t id

mesh event id

mesh_event_info_t info

mesh event info

struct mesh_opt_t

Mesh option.

Public Members

uint8_t type

option type

uint16_t len

option length

uint8_t *val

option value

struct mesh_data_t

Mesh data for esp_mesh_send() and esp_mesh_recv()

Public Members

uint8_t *data

data

uint16_t size

data size

mesh_proto_t proto

data protocol

mesh_tos_t tos

data type of service

struct mesh_router_t

Router configuration.

Public Members

uint8_t ssid[32]

SSID

uint8_t ssid_len

length of SSID

uint8_t bssid[6]

BSSID, if this value is specified, users should also specify “allow_router_switch”.

uint8_t password[64]

password

bool allow_router_switch

if the BSSID is specified and this value is also set, when the router of this specified BSSID fails to be found after “fail” (mesh_attempts_t) times, the whole network is allowed to switch to another router with the same SSID. The new router might also be on a different channel. The default value is false. There is a risk that if the password is different between the new switched router and the previous one, the mesh network could be established but the root will never connect to the new switched router.

struct mesh_ap_cfg_t

Mesh softAP configuration.

Public Members

uint8_t password[64]

mesh softAP password

uint8_t max_connection

max number of stations allowed to connect in, max 10

struct mesh_cfg_t

Mesh initialization configuration.

Public Members

uint8_t channel

channel, the mesh network on

bool allow_channel_switch

if this value is set, when “fail” (mesh_attempts_t) times is reached, device will change to a full channel scan for a network that could join. The default value is false.

mesh_event_cb_t event_cb

mesh event callback

mesh_addr_t mesh_id

mesh network identification

mesh_router_t router

router configuration

mesh_ap_cfg_t mesh_ap

mesh softAP configuration

const mesh_crypto_funcs_t *crypto_funcs

crypto functions

struct mesh_vote_t

Vote.

Public Members

float percentage

vote percentage threshold for approval of being a root

bool is_rc_specified

if true, rc_addr shall be specified (Unimplemented). if false, attempts value shall be specified to make network start root election.

mesh_rc_config_t config

vote address configuration

struct mesh_tx_pending_t

The number of packets pending in the queue waiting to be sent by the mesh stack.

Public Members

int to_parent

to parent queue

int to_parent_p2p

to parent (P2P) queue

int to_child

to child queue

int to_child_p2p

to child (P2P) queue

int mgmt

management queue

int broadcast

broadcast and multicast queue

struct mesh_rx_pending_t

The number of packets available in the queue waiting to be received by applications.

Public Members

int toDS

to external DS

int toSelf

to self

Macros

MESH_ROOT_LAYER

root layer value

MESH_MTU

max transmit unit(in bytes)

MESH_MPS

max payload size(in bytes)

ESP_ERR_MESH_WIFI_NOT_START

Mesh error code definition.

Wi-Fi isn’t started

ESP_ERR_MESH_NOT_INIT

mesh isn’t initialized

ESP_ERR_MESH_NOT_CONFIG

mesh isn’t configured

ESP_ERR_MESH_NOT_START

mesh isn’t started

ESP_ERR_MESH_NOT_SUPPORT

not supported yet

ESP_ERR_MESH_NOT_ALLOWED

operation is not allowed

ESP_ERR_MESH_NO_MEMORY

out of memory

ESP_ERR_MESH_ARGUMENT

illegal argument

ESP_ERR_MESH_EXCEED_MTU

packet size exceeds MTU

ESP_ERR_MESH_TIMEOUT

timeout

ESP_ERR_MESH_DISCONNECTED

disconnected with parent on station interface

ESP_ERR_MESH_QUEUE_FAIL

queue fail

ESP_ERR_MESH_QUEUE_FULL

queue full

ESP_ERR_MESH_NO_PARENT_FOUND

no parent found to join the mesh network

ESP_ERR_MESH_NO_ROUTE_FOUND

no route found to forward the packet

ESP_ERR_MESH_OPTION_NULL

no option found

ESP_ERR_MESH_OPTION_UNKNOWN

unknown option

ESP_ERR_MESH_XON_NO_WINDOW

no window for software flow control on upstream

ESP_ERR_MESH_INTERFACE

low-level Wi-Fi interface error

ESP_ERR_MESH_DISCARD_DUPLICATE

discard the packet due to the duplicate sequence number

ESP_ERR_MESH_DISCARD

discard the packet

ESP_ERR_MESH_VOTING

vote in progress

MESH_DATA_ENC

Flags bitmap for esp_mesh_send() and esp_mesh_recv()

data encrypted (Unimplemented)

MESH_DATA_P2P

point-to-point delivery over the mesh network

MESH_DATA_FROMDS

receive from external IP network

MESH_DATA_TODS

identify this packet is target to external IP network

MESH_DATA_NONBLOCK

esp_mesh_send() non-block

MESH_DATA_DROP

in the situation of the root having been changed, identify this packet can be dropped by new root

MESH_DATA_GROUP

identify this packet is target to a group address

MESH_OPT_SEND_GROUP

Option definitions for esp_mesh_send() and esp_mesh_recv()

data transmission by group; used with esp_mesh_send() and shall have payload

MESH_OPT_RECV_DS_ADDR

return a remote IP address; used with esp_mesh_send() and esp_mesh_recv()

MESH_ASSOC_FLAG_VOTE_IN_PROGRESS

Flag of mesh networking IE.

vote in progress

MESH_ASSOC_FLAG_NETWORK_FREE

no root in current network

MESH_ASSOC_FLAG_ROOTS_FOUND

root conflict is found

MESH_ASSOC_FLAG_ROOT_FIXED

fixed root

MESH_INIT_CONFIG_DEFAULT()

Type Definitions

typedef system_event_sta_got_ip_t mesh_event_root_got_ip_t

IP settings from LwIP stack.

typedef mesh_addr_t mesh_event_root_address_t

Root address.

typedef system_event_sta_disconnected_t mesh_event_disconnected_t

Parent disconnected information.

typedef system_event_ap_staconnected_t mesh_event_child_connected_t

Child connected information.

typedef system_event_ap_stadisconnected_t mesh_event_child_disconnected_t

Child disconnected information.

typedef system_event_sta_connected_t mesh_event_router_switch_t

New router information.

typedef void (*mesh_event_cb_t)(mesh_event_t event)

Mesh event callback handler prototype definition.

Parameters

Enumerations

enum mesh_event_id_t

Enumerated list of mesh event id.

Values:

MESH_EVENT_STARTED

mesh is started

MESH_EVENT_STOPPED

mesh is stopped

MESH_EVENT_CHANNEL_SWITCH

channel switch

MESH_EVENT_CHILD_CONNECTED

a child is connected on softAP interface

MESH_EVENT_CHILD_DISCONNECTED

a child is disconnected on softAP interface

MESH_EVENT_ROUTING_TABLE_ADD

routing table is changed by adding newly joined children

MESH_EVENT_ROUTING_TABLE_REMOVE

routing table is changed by removing leave children

MESH_EVENT_PARENT_CONNECTED

parent is connected on station interface

MESH_EVENT_PARENT_DISCONNECTED

parent is disconnected on station interface

MESH_EVENT_NO_PARENT_FOUND

no parent found

MESH_EVENT_LAYER_CHANGE

layer changes over the mesh network

MESH_EVENT_TODS_STATE

state represents whether the root is able to access external IP network

MESH_EVENT_VOTE_STARTED

the process of voting a new root is started either by children or by the root

MESH_EVENT_VOTE_STOPPED

the process of voting a new root is stopped

MESH_EVENT_ROOT_ADDRESS

the root address is obtained. It is posted by mesh stack automatically.

MESH_EVENT_ROOT_SWITCH_REQ

root switch request sent from a new voted root candidate

MESH_EVENT_ROOT_SWITCH_ACK

root switch acknowledgment responds the above request sent from current root

MESH_EVENT_ROOT_GOT_IP

the root obtains the IP address. It is posted by LwIP stack automatically

MESH_EVENT_ROOT_LOST_IP

the root loses the IP address. It is posted by LwIP stack automatically

MESH_EVENT_ROOT_ASKED_YIELD

the root is asked yield by a more powerful existing root. If self organized is disabled and this device is specified to be a root by users, users should set a new parent for this device. if self organized is enabled, this device will find a new parent by itself, users could ignore this event.

MESH_EVENT_ROOT_FIXED

when devices join a network, if the setting of Fixed Root for one device is different from that of its parent, the device will update the setting the same as its parent’s. Fixed Root Setting of each device is variable as that setting changes of the root.

MESH_EVENT_SCAN_DONE

if self-organized networking is disabled, user can call esp_wifi_scan_start() to trigger this event, and add the corresponding scan done handler in this event.

MESH_EVENT_NETWORK_STATE

network state, such as whether current mesh network has a root.

MESH_EVENT_STOP_RECONNECTION

the root stops reconnecting to the router and non-root devices stop reconnecting to their parents.

MESH_EVENT_FIND_NETWORK

when the channel field in mesh configuration is set to zero, mesh stack will perform a full channel scan to find a mesh network that can join, and return the channel value after finding it.

MESH_EVENT_ROUTER_SWITCH

if users specify BSSID of the router in mesh configuration, when the root connects to another router with the same SSID, this event will be posted and the new router information is attached.

MESH_EVENT_MAX
enum mesh_type_t

Device type.

Values:

MESH_IDLE

hasn’t joined the mesh network yet

MESH_ROOT

the only sink of the mesh network. Has the ability to access external IP network

MESH_NODE

intermediate device. Has the ability to forward packets over the mesh network

MESH_LEAF

has no forwarding ability

enum mesh_proto_t

Protocol of transmitted application data.

Values:

MESH_PROTO_BIN

binary

MESH_PROTO_HTTP

HTTP protocol

MESH_PROTO_JSON

JSON format

MESH_PROTO_MQTT

MQTT protocol

enum mesh_tos_t

For reliable transmission, mesh stack provides three type of services.

Values:

MESH_TOS_P2P

provide P2P (point-to-point) retransmission on mesh stack by default

MESH_TOS_E2E

provide E2E (end-to-end) retransmission on mesh stack (Unimplemented)

MESH_TOS_DEF

no retransmission on mesh stack

enum mesh_vote_reason_t

Vote reason.

Values:

MESH_VOTE_REASON_ROOT_INITIATED = 1

vote is initiated by the root

MESH_VOTE_REASON_CHILD_INITIATED

vote is initiated by children

enum mesh_disconnect_reason_t

Mesh disconnect reason code.

Values:

MESH_REASON_CYCLIC = 100

cyclic is detected

MESH_REASON_PARENT_IDLE

parent is idle

MESH_REASON_LEAF

the connected device is changed to a leaf

MESH_REASON_DIFF_ID

in different mesh ID

MESH_REASON_ROOTS

root conflict is detected

MESH_REASON_PARENT_STOPPED

parent has stopped the mesh

MESH_REASON_SCAN_FAIL

scan fail

MESH_REASON_IE_UNKNOWN

unknown IE

MESH_REASON_WAIVE_ROOT

waive root

MESH_REASON_PARENT_WORSE

parent with very poor RSSI

MESH_REASON_EMPTY_PASSWORD

use an empty password to connect to an encrypted parent

MESH_REASON_PARENT_UNENCRYPTED

connect to an unencrypted parent/router

enum mesh_event_toDS_state_t

The reachability of the root to a DS (distribute system)

Values:

MESH_TODS_UNREACHABLE

the root isn’t able to access external IP network

MESH_TODS_REACHABLE

the root is able to access external IP network