ESP-NETIF Programmers Manual

Configure IP, Gateway, and DNS

Typically, IP addresses -- including the gateway, network mask, and DNS servers -- are automatically obtained through a DHCP server or Router Advertisement services. Notifications regarding IP address assignments are received via the IP_EVENT, which provides the relevant IP address information. You can also retrieve the current address details using the function esp_netif_get_ip_info(). This function returns a structure, esp_netif_ip_info_t, that contains the IPv4 address of the network interface, along with its network mask and gateway address. Similarly, the function esp_netif_get_all_ip6() can be used to obtain all IPv6 addresses associated with the interface.

In order to configure static IP addresses and DNS servers, it's necessary to disable or stop DHCP client (which is enabled by default on some network interfaces, such as the default Ethernet, or the default WiFi station). Please refer to the example /protocols/static_ip for more details.

To set IPv4 address, you can use esp_netif_set_ip_info(). For IPv6, these two functions can be used for adding or removing addresses: esp_netif_add_ip6_address(), esp_netif_remove_ip6_address(). To configure DNS servers, please use esp_netif_set_dns_info() API.

Configure DHCP options

Some network interfaces are pre-configured to use either a DHCP client (commonly for Ethernet interfaces) or a DHCP server (typically for Wi-Fi software access points). When manually creating a custom network interface, the configuration flags esp_netif_flags_t are used to specify the behavior of the interface. Adding ESP_NETIF_DHCP_CLIENT or ESP_NETIF_DHCP_SERVER will enable the DHCP client or server, respectively.

It is important to note that these two options are mutually exclusive and cannot be changed at runtime. If an interface is configured as a DHCP client upon creation, it cannot later be used as a DHCP server. The only option is to destroy the existing network interface and create a new one with the desired configuration.

To set or get a specific DHCP option, the common type esp_netif_dhcp_option_id_t is used for both the DHCP server and client. However, not all options are supported for both. For details on the available options for the DHCP client, refer to the API documentation for esp_netif_dhcpc_option(). Similarly, for the options available for the DHCP server, consult the API documentation for esp_netif_dhcps_option().

SNTP Service

A brief introduction to SNTP, its initialization code, and basic modes can be found in Section SNTP 时间同步 in System Time.

This section provides more details on specific use cases for the SNTP service, such as using statically configured servers, DHCP-provided servers, or both. The workflow is typically straightforward:

Initialize and configure the service using esp_netif_sntp_init(). This function can only be called once unless the SNTP service has been destroyed using esp_netif_sntp_deinit().
Start the service with esp_netif_sntp_start(). This step is not necessary if the service was auto-started in the previous step (default behavior). However, it can be useful to start the service explicitly after connecting if DHCP-provided NTP servers are being used. Note that this option needs to be enabled before connecting, but the SNTP service should only be started afterward.
Wait for the system time to synchronize using esp_netif_sntp_sync_wait() (if required).
Stop and destroy the service using esp_netif_sntp_deinit().

Basic Mode with Statically Defined Server(s)

Initialize the module with the default configuration after connecting to the network. Note that it is possible to provide multiple NTP servers in the configuration struct:

esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG_MULTIPLE(2,
                           ESP_SNTP_SERVER_LIST("time.windows.com", "pool.ntp.org" ) );
esp_netif_sntp_init(&config);

备注

If you want to configure multiple SNTP servers, update the lwIP configuration option CONFIG_LWIP_SNTP_MAX_SERVERS.

Use DHCP-Obtained SNTP Server(s)

First, you need to enable the lwIP configuration option CONFIG_LWIP_DHCP_GET_NTP_SRV. Then, initialize the SNTP module with the DHCP option, without specifying an NTP server.

esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG_MULTIPLE(0, {} );
config.start = false;                       // start the SNTP service explicitly
config.server_from_dhcp = true;             // accept the NTP offer from the DHCP server
esp_netif_sntp_init(&config);

Once connected, you can start the service using:

esp_netif_sntp_start();

备注

It is also possible to start the service during initialization (with the default config.start=true). However, this may cause the initial SNTP request to fail since you are not connected yet, which could result in a back-off period for subsequent requests.

Use Both Static and Dynamic Servers

This scenario is similar to using DHCP-provided SNTP servers. However, in this configuration, you need to ensure that the static server configuration is refreshed when obtaining NTP servers via DHCP. The underlying lwIP code removes the existing list of NTP servers when DHCP-provided information is accepted. Therefore, the ESP-NETIF SNTP module retains the statically configured server(s) and appends them to the list after obtaining a DHCP lease.

The typical configuration now looks as per below, providing the specific IP_EVENT to update the config and index of the first server to reconfigure (for example setting config.index_of_first_server=1 would keep the DHCP provided server at index 0, and the statically configured server at index 1).

esp_sntp_config_t config = ESP_NETIF_SNTP_DEFAULT_CONFIG("pool.ntp.org");
config.start = false;                       // start the SNTP service explicitly (after connecting)
config.server_from_dhcp = true;             // accept the NTP offers from DHCP server
config.renew_servers_after_new_IP = true;   // let esp-netif update the configured SNTP server(s) after receiving the DHCP lease
config.index_of_first_server = 1;           // updates from server num 1, leaving server 0 (from DHCP) intact
config.ip_event_to_renew = IP_EVENT_STA_GOT_IP;  // IP event on which you refresh your configuration

Then you start the service normally with esp_netif_sntp_start().

L2 TAP Interface Usage

The ESP-NETIF L2 TAP interface is used to access Data Link Layer, please refer to the ESP-NETIF 架构 diagram to see how L2 TAP interacts with ESP-NETIF and application.

From a user perspective, the ESP-NETIF L2 TAP interface is accessed using file descriptors of VFS, which provides file-like interfacing (using functions like open(), read(), write(), etc). To learn more, refer to 虚拟文件系统组件.

There is only one ESP-NETIF L2 TAP interface device (path name) available, but you can open multiple file descriptors from it, each with its own unique configuration. Think of the ESP-NETIF L2 TAP interface as a general gateway to the Layer 2 network infrastructure. The key point is that each file descriptor can be individually configured, which is crucial. For example, a file descriptor can be set up to access a specific network interface identified by if_key (like ETH_DEF) and to filter specific types of frames (such as filtering by Ethernet type for IEEE 802.3 frames).

This filtering is essential because the ESP-NETIF L2 TAP works alongside the IP stack, meaning that IP-related traffic (like IP, ARP, etc.) should not be sent directly to your application. Although this option is still possible, it is not recommended in standard use cases. The benefit of filtering is that it allows your application to receive only the frame types it cares about, while other traffic is either routed to different L2 TAP file descriptors or handled by the IP stack.

Initialization

To be able to use the ESP-NETIF L2 TAP interface, it needs to be enabled in Kconfig by CONFIG_ESP_NETIF_L2_TAP first and then registered by esp_vfs_l2tap_intf_register() prior usage of any VFS function.

`open()`

Once the ESP-NETIF L2 TAP is registered, it can be opened at path name "/dev/net/tap". The same path name can be opened multiple times up to CONFIG_ESP_NETIF_L2_TAP_MAX_FDS and multiple file descriptors with a different configuration may access the Data Link Layer frames.

The ESP-NETIF L2 TAP can be opened with the O_NONBLOCK file status flag to make sure the read() does not block. Note that the write() may block in the current implementation when accessing a Network interface since it is a shared resource among multiple ESP-NETIF L2 TAP file descriptors and IP stack, and there is currently no queuing mechanism deployed. The file status flag can be retrieved and modified using fcntl().

On success, open() returns the new file descriptor (a nonnegative integer). On error, -1 is returned, and errno is set to indicate the error.

`ioctl()`

The newly opened ESP-NETIF L2 TAP file descriptor needs to be configured prior to its usage since it is not bounded to any specific Network Interface and no frame type filter is configured. The following configuration options are available to do so:

L2TAP_S_INTF_DEVICE - bounds the file descriptor to a specific Network Interface that is identified by its if_key. ESP-NETIF Network Interface if_key is passed to ioctl() as the third parameter. Note that default Network Interfaces if_key's used in ESP-IDF can be found in esp_netif/include/esp_netif_defaults.h.

L2TAP_S_DEVICE_DRV_HNDL - is another way to bound the file descriptor to a specific Network Interface. In this case, the Network interface is identified directly by IO Driver handle (e.g., esp_eth_handle_t in case of Ethernet). The IO Driver handle is passed to ioctl() as the third parameter.

L2TAP_S_RCV_FILTER - sets the filter to frames with the type to be passed to the file descriptor. In the case of Ethernet frames, the frames are to be filtered based on the Length and Ethernet type field. In case the filter value is set less than or equal to 0x05DC, the Ethernet type field is considered to represent IEEE802.3 Length Field, and all frames with values in interval <0, 0x05DC> at that field are passed to the file descriptor. The IEEE802.2 logical link control (LLC) resolution is then expected to be performed by the user's application. In case the filter value is set greater than 0x05DC, the Ethernet type field is considered to represent protocol identification and only frames that are equal to the set value are to be passed to the file descriptor.

L2TAP_S_TIMESTAMP_EN - enables the hardware Time Stamping processing inside the file descriptor. The Time Stamps are retrieved to user space by using Extended Buffer mechanism when accessing the file descriptor by read() and write() functions. Hardware time stamping needs to be supported by target and needs to be enabled in IO Driver to this option work as expected.

All above-set configuration options have a getter counterpart option to read the current settings except for L2TAP_S_TIMESTAMP_EN.

警告

The file descriptor needs to be firstly bounded to a specific Network Interface by L2TAP_S_INTF_DEVICE or L2TAP_S_DEVICE_DRV_HNDL to make L2TAP_S_RCV_FILTER option available.

备注

VLAN-tagged frames are currently not recognized. If the user needs to process VLAN-tagged frames, they need a set filter to be equal to the VLAN tag (i.e., 0x8100 or 0x88A8) and process the VLAN-tagged frames in the user application.

备注

L2TAP_S_DEVICE_DRV_HNDL is particularly useful when the user's application does not require the usage of an IP stack and so ESP-NETIF is not required to be initialized too. As a result, Network Interface cannot be identified by its if_key and hence it needs to be identified directly by its IO Driver handle.

On success, ioctl() returns 0. On error, -1 is returned, and errno is set to indicate the error.
* EBADF - not a valid file descriptor.
* EACCES - options change is denied in this state (e.g., file descriptor has not been bounded to Network interface yet).
* EINVAL - invalid configuration argument. Ethernet type filter is already used by other file descriptors on that same Network interface.
* ENODEV - no such Network Interface which is tried to be assigned to the file descriptor exists.
* ENOSYS - unsupported operation, passed configuration option does not exist.

`fcntl()`

The fcntl() is used to manipulate with properties of opened ESP-NETIF L2 TAP file descriptor.

The following commands manipulate the status flags associated with the file descriptor:

F_GETFD - the function returns the file descriptor flags, and the third argument is ignored.

F_SETFD - sets the file descriptor flags to the value specified by the third argument. Zero is returned.

On success, fcntl() returns 0. On error, -1 is returned, and errno is set to indicate the error.
* EBADF - not a valid file descriptor.
* ENOSYS - unsupported command.

`read()`

Opened and configured ESP-NETIF L2 TAP file descriptor can be accessed by read() to get inbound frames. The read operation can be either blocking or non-blocking based on the actual state of the O_NONBLOCK file status flag. When the file status flag is set to blocking, the read operation waits until a frame is received and the context is switched to other tasks. When the file status flag is set to non-blocking, the read operation returns immediately. In such case, either a frame is returned if it was already queued or the function indicates the queue is empty. The number of queued frames associated with one file descriptor is limited by CONFIG_ESP_NETIF_L2_TAP_RX_QUEUE_SIZE Kconfig option. Once the number of queued frames reached a configured threshold, the newly arrived frames are dropped until the queue has enough room to accept incoming traffic (Tail Drop queue management).

On success, read() returns the number of bytes read. Zero is returned when the size of the destination buffer is 0. On error, -1 is returned, and errno is set to indicate the error.
* EBADF - not a valid file descriptor.
* EAGAIN - the file descriptor has been marked non-blocking (O_NONBLOCK), and the read would block.

备注

ESP-NETIF L2 TAP read() implementation extends the standard and offers Extended Buffer mechanism to retrieve additional information about received frame. See Extended Buffer section for more information.

`write()`

A raw Data Link Layer frame can be sent to Network Interface via opened and configured ESP-NETIF L2 TAP file descriptor. The user's application is responsible to construct the whole frame except for fields which are added automatically by the physical interface device. The following fields need to be constructed by the user's application in case of an Ethernet link: source/destination MAC addresses, Ethernet type, actual protocol header, and user data. The length of these fields is as follows:

In other words, there is no additional frame processing performed by the ESP-NETIF L2 TAP interface. It only checks the Ethernet type of the frame is the same as the filter configured in the file descriptor. If the Ethernet type is different, an error is returned and the frame is not sent. Note that the write() may block in the current implementation when accessing a Network interface since it is a shared resource among multiple ESP-NETIF L2 TAP file descriptors and IP stack, and there is currently no queuing mechanism deployed.

On success, write() returns the number of bytes written. Zero is returned when the size of the input buffer is 0. On error, -1 is returned, and errno is set to indicate the error.
* EBADF - not a valid file descriptor.
* EBADMSG - The Ethernet type of the frame is different from the file descriptor configured filter.
* EIO - Network interface not available or busy.

备注

ESP-NETIF L2 TAP write() implementation extends the standard and offers Extended Buffer mechanism to retrieve additional information about transmitted frame. See Extended Buffer section for more information.

`close()`

Opened ESP-NETIF L2 TAP file descriptor can be closed by the close() to free its allocated resources. The ESP-NETIF L2 TAP implementation of close() may block. On the other hand, it is thread-safe and can be called from a different task than the file descriptor is actually used. If such a situation occurs and one task is blocked in the I/O operation and another task tries to close the file descriptor, the first task is unblocked. The first's task read operation then ends with returning 0 bytes was read.

On success, close() returns zero. On error, -1 is returned, and errno is set to indicate the error.

* EBADF - not a valid file descriptor.

`select()`

Select is used in a standard way, just CONFIG_VFS_SUPPORT_SELECT needs to be enabled to make the select() function available.

Extended Buffer

The Extended Buffer is ESP-NETIF L2 TAP's mechanism of how to retrieve additional information about transmitted or received IO frame via write() or read() functions. The Extended Buffer must be only used when specific functionality is enabled in the file descriptor (such as L2TAP_S_TIMESTAMP_EN) and you want to access the additional data (such as Time Stamp) or control the frame processing.

The Extended Buffer is a structure with fields which serve as arguments to drive underlying functionality in the ESP-NETIF L2 TAP file descriptor. The structure is defined as follows:

typedef struct {
    size_t info_recs_len;       /*!< Length of Information Records buffer */
    void *info_recs_buff;       /*!< Buffer holding extended information (IRECs) related to IO frames */
    size_t buff_len;            /*!< Length of the actual IO Frame buffer */
    void *buff;                 /*!< Pointer to the IO Frame buffer */
} l2tap_extended_buff_t;

One Extended buffer may hold multiple Information Records (IRECs). These are variable data typed (and sized) records which may hold any datatype of additional information associated with the IO frame. The IREC structure is defined as follows:

typedef struct
{
    size_t len;                         /*!< Length of the record including header and data*/
    l2tap_irec_type_t type;             /*!< Type of the record */
    alignas(long long) uint8_t data[];  /*!< Records Data aligned to double word */
} l2tap_irec_hdr_t;

Currently implement and used IREC data types are defined in l2tap_irec_type_t.

Since the flexible array to hold data is used, proper memory alignment of multiple IRECs in the records buffer is required to correctly access memory. Improper alignment can result in slower memory access due to misaligned read/write operations, or in the worst case, cause undefined behavior on certain architectures. Therefore it is strictly recommended to use the below macros when manipulating with IRECs:

L2TAP_IREC_SPACE() - determines the space required for an IREC, ensuring that it is properly aligned.
L2TAP_IREC_LEN() - calculates the total length of one IREC, including the header and the data section of the record.
L2TAP_IREC_FIRST() - retrieves the first IREC from the l2tap_extended_buff_t::info_recs_buff pool of Extended Buffer. If the l2tap_extended_buff_t::info_recs_len is smaller than the size of a record header, it returns NULL.
L2TAP_IREC_NEXT() - retrieves the next IREC in the Extended Buffer after the current record. If the current record is NULL, it returns the first record.

Extended Buffer Usage

Prior any Extended Buffer IO operation (either write() or read()), you first need to fully populate the Extended Buffer and its IREC fields. For example, when you want to retrieve Time Stamp, you need to set type of the IREC to L2TAP_IREC_TIME_STAMP and configure appropriate length. If you don't set the type correctly, the frame is still received or transmitted but information to be retrieved is lost. Similarly, when the IREC length is less than expected length, the frame is still received or transmitted but the type of affected IREC is marked to L2TAP_IREC_INVALID by the ESP-NETIF L2 TAP and information to be retrieved is lost.

When accessing the file descriptor using Extended Buffer, size parameter of write() or read() function must be set equal to 0. Failing to do so (i.e. accessing such file descriptor in a standard way with size parameter set to data length) will result in an -1 error and errno set to EINVAL.

// wrap "Info Records Buffer" into union to ensure proper alignment of data (this is typically needed when
// accessing double word variables or structs containing double word variables)
union {
    uint8_t info_recs_buff[L2TAP_IREC_SPACE(sizeof(struct timespec))];
    l2tap_irec_hdr_t align;
} u;

l2tap_extended_buff_t ptp_msg_ext_buff;

ptp_msg_ext_buff.info_recs_len = sizeof(u.info_recs_buff);
ptp_msg_ext_buff.info_recs_buff = u.info_recs_buff;
ptp_msg_ext_buff.buff = eth_frame;
ptp_msg_ext_buff.buff_len = sizeof(eth_frame);

l2tap_irec_hdr_t *ts_info = L2TAP_IREC_FIRST(&ptp_msg_ext_buff);
ts_info->len = L2TAP_IREC_LEN(sizeof(struct timespec));
ts_info->type = L2TAP_IREC_TIME_STAMP;

int ret = write(state->ptp_socket, &ptp_msg_ext_buff, 0);

// check if write was successful and ts_info is valid
if (ret > 0 && ts_info->type == L2TAP_IREC_TIME_STAMP) {
    *ts = *(struct timespec *)ts_info->data;
}

IP Event: Transmit/Receive Packet

This event, IP_EVENT_TX_RX, is triggered for every transmitted or received IP packet. It provides information about packet transmission or reception, data length, and the esp_netif handle.

Enabling the Event

Compile Time:

The feature can be completely disabled during compilation time using the flag CONFIG_ESP_NETIF_REPORT_DATA_TRAFFIC in the kconfig.

Run Time:

At runtime, you can enable or disable this event using the functions esp_netif_tx_rx_event_enable() and esp_netif_tx_rx_event_disable().

Event Registration

To handle this event, you need to register a handler using the following syntax:

static void
tx_rx_event_handler(void *arg, esp_event_base_t event_base,
                                int32_t event_id, void *event_data)
{
    ip_event_tx_rx_t *event = (ip_event_tx_rx_t *)event_data;

    if (event->dir == ESP_NETIF_TX) {
        ESP_LOGI(TAG, "Got TX event: Interface \"%s\" data len: %d", esp_netif_get_desc(event->esp_netif), event->len);
    } else if (event->dir == ESP_NETIF_RX) {
        ESP_LOGI(TAG, "Got RX event: Interface \"%s\" data len: %d", esp_netif_get_desc(event->esp_netif), event->len);
    } else {
        ESP_LOGI(TAG, "Got Unknown event: Interface \"%s\"", esp_netif_get_desc(event->esp_netif));
    }
}

esp_event_handler_register(IP_EVENT, IP_EVENT_TX_RX, &tx_rx_event_handler, NULL);

Here, tx_rx_event_handler is the name of the function that will handle the event.

Event Data Structure

The event data structure, ip_event_tx_rx_t, contains the following fields:

ip_event_tx_rx_t::dir: Indicates whether the packet was transmitted (ESP_NETIF_TX) or received (ESP_NETIF_RX).
ip_event_tx_rx_t::len: Length of the data frame.
ip_event_tx_rx_t::esp_netif: The network interface on which the packet was sent or received.

API Reference

Header File

components/esp_netif/include/esp_netif.h
This header file can be included with:
#include "esp_netif.h"
This header file is a part of the API provided by the esp_netif component. To declare that your component depends on esp_netif, add the following to your CMakeLists.txt:
REQUIRES esp_netif
or
PRIV_REQUIRES esp_netif

Header File

components/esp_netif/include/esp_netif_sntp.h
This header file can be included with:
#include "esp_netif_sntp.h"
This header file is a part of the API provided by the esp_netif component. To declare that your component depends on esp_netif, add the following to your CMakeLists.txt:
REQUIRES esp_netif
or
PRIV_REQUIRES esp_netif

Structures

struct esp_sntp_config

SNTP configuration struct.

Public Members

bool smooth_sync: set to true if smooth sync required

bool server_from_dhcp: set to true to request NTP server config from DHCP

bool wait_for_sync: if true, we create a semaphore to signal time sync event

bool start: set to true to automatically start the SNTP service

esp_sntp_time_cb_t sync_cb: optionally sets callback function on time sync event

bool renew_servers_after_new_IP: this is used to refresh server list if NTP provided by DHCP (which cleans other pre-configured servers)

ip_event_t ip_event_to_renew: set the IP event id on which we refresh server list (if renew_servers_after_new_IP=true)

size_t index_of_first_server: refresh server list after this server (if renew_servers_after_new_IP=true)

size_t num_of_servers: number of preconfigured NTP servers

const char *servers[1]: list of servers

Header File

components/esp_netif/include/esp_netif_types.h
This header file can be included with:
#include "esp_netif_types.h"
This header file is a part of the API provided by the esp_netif component. To declare that your component depends on esp_netif, add the following to your CMakeLists.txt:
REQUIRES esp_netif
or
PRIV_REQUIRES esp_netif

Structures

struct esp_netif_dns_info_t

DNS server info.

Public Members

esp_ip_addr_t ip: IPV4 address of DNS server

struct esp_netif_ip_info_t

Event structure for IP_EVENT_STA_GOT_IP, IP_EVENT_ETH_GOT_IP events

Public Members

esp_ip4_addr_t ip: Interface IPV4 address

esp_ip4_addr_t netmask: Interface IPV4 netmask

esp_ip4_addr_t gw: Interface IPV4 gateway address

struct esp_netif_ip6_info_t

IPV6 IP address information.

Public Members

esp_ip6_addr_t ip: Interface IPV6 address

struct ip_event_got_ip_t

Event structure for IP_EVENT_GOT_IP event.

Public Members

esp_netif_t *esp_netif: Pointer to corresponding esp-netif object

esp_netif_ip_info_t ip_info: IP address, netmask, gateway IP address

bool ip_changed: Whether the assigned IP has changed or not

struct ip_event_got_ip6_t

Event structure for IP_EVENT_GOT_IP6 event

Public Members

esp_netif_t *esp_netif: Pointer to corresponding esp-netif object

esp_netif_ip6_info_t ip6_info: IPv6 address of the interface

int ip_index: IPv6 address index

struct ip_event_add_ip6_t

Event structure for ADD_IP6 event

Public Members

esp_ip6_addr_t addr: The address to be added to the interface

bool preferred: The default preference of the address

struct ip_event_ap_staipassigned_t

Event structure for IP_EVENT_AP_STAIPASSIGNED event

Public Members

esp_netif_t *esp_netif: Pointer to the associated netif handle

esp_ip4_addr_t ip: IP address which was assigned to the station

uint8_t mac[6]: MAC address of the connected client

struct ip_event_tx_rx_t

Event structure for IP_EVENT_TRANSMIT and IP_EVENT_RECEIVE

Public Members

esp_netif_t *esp_netif: Pointer to the associated netif handle

size_t len: Length of the data

esp_netif_tx_rx_direction_t dir: Directions for data transfer >

struct bridgeif_config

LwIP bridge configuration

Public Members

uint16_t max_fdb_dyn_entries: maximum number of entries in dynamic forwarding database

uint16_t max_fdb_sta_entries: maximum number of entries in static forwarding database

uint8_t max_ports: maximum number of ports the bridge can consist of

struct esp_netif_inherent_config

ESP-netif inherent config parameters.

Public Members

esp_netif_flags_t flags: flags that define esp-netif behavior

uint8_t mac[6]: initial mac address for this interface

const esp_netif_ip_info_t *ip_info: initial ip address for this interface

uint32_t get_ip_event: event id to be raised when interface gets an IP

uint32_t lost_ip_event: event id to be raised when interface losts its IP

const char *if_key: string identifier of the interface

const char *if_desc: textual description of the interface

int route_prio: numeric priority of this interface to become a default routing if (if other netifs are up). A higher value of route_prio indicates a higher priority

bridgeif_config_t *bridge_info: LwIP bridge configuration

struct esp_netif_driver_base_s

ESP-netif driver base handle.

Public Members

esp_err_t (*post_attach)(esp_netif_t *netif, esp_netif_iodriver_handle h): post attach function pointer

esp_netif_t *netif: netif handle

struct esp_netif_driver_ifconfig

Specific IO driver configuration.

Public Members

esp_netif_iodriver_handle handle: io-driver handle

esp_err_t (*transmit)(void *h, void *buffer, size_t len): transmit function pointer

esp_err_t (*transmit_wrap)(void *h, void *buffer, size_t len, void *netstack_buffer): transmit wrap function pointer

void (*driver_free_rx_buffer)(void *h, void *buffer): free rx buffer function pointer

esp_err_t (*driver_set_mac_filter)(void *h, const uint8_t *mac, size_t mac_len, bool add): set mac filter function pointer

struct esp_netif_config

Generic esp_netif configuration.

Public Members

const esp_netif_inherent_config_t *base: base config

const esp_netif_driver_ifconfig_t *driver: driver config

const esp_netif_netstack_config_t *stack: stack config

struct esp_netif_pair_mac_ip_t

DHCP client's addr info (pair of MAC and IP address)

Public Members

uint8_t mac[6]: Clients MAC address

esp_ip4_addr_t ip: Clients IP address

Macros

ESP_ERR_ESP_NETIF_BASE: Definition of ESP-NETIF based errors.

ESP_ERR_ESP_NETIF_INVALID_PARAMS

ESP_ERR_ESP_NETIF_IF_NOT_READY

ESP_ERR_ESP_NETIF_DHCPC_START_FAILED

ESP_ERR_ESP_NETIF_DHCP_ALREADY_STARTED

ESP_ERR_ESP_NETIF_DHCP_ALREADY_STOPPED

ESP_ERR_ESP_NETIF_NO_MEM

ESP_ERR_ESP_NETIF_DHCP_NOT_STOPPED

ESP_ERR_ESP_NETIF_DRIVER_ATTACH_FAILED

ESP_ERR_ESP_NETIF_INIT_FAILED

ESP_ERR_ESP_NETIF_DNS_NOT_CONFIGURED

ESP_ERR_ESP_NETIF_MLD6_FAILED

ESP_ERR_ESP_NETIF_IP6_ADDR_FAILED

ESP_ERR_ESP_NETIF_DHCPS_START_FAILED

ESP_ERR_ESP_NETIF_TX_FAILED

ESP_NETIF_BR_FLOOD: Definition of ESP-NETIF bridge control.

ESP_NETIF_BR_DROP

ESP_NETIF_BR_FDW_CPU

Type Definitions

typedef struct esp_netif_obj esp_netif_t

typedef enum esp_netif_flags esp_netif_flags_t

typedef enum esp_netif_ip_event_type esp_netif_ip_event_type_t

typedef struct bridgeif_config bridgeif_config_t: LwIP bridge configuration

typedef struct esp_netif_inherent_config esp_netif_inherent_config_t: ESP-netif inherent config parameters.

typedef struct esp_netif_config esp_netif_config_t

typedef void *esp_netif_iodriver_handle: IO driver handle type.

typedef struct esp_netif_driver_base_s esp_netif_driver_base_t: ESP-netif driver base handle.

typedef struct esp_netif_driver_ifconfig esp_netif_driver_ifconfig_t

typedef struct esp_netif_netstack_config esp_netif_netstack_config_t: Specific L3 network stack configuration.

typedef esp_err_t (*esp_netif_receive_t)(esp_netif_t *esp_netif, void *buffer, size_t len, void *eb): ESP-NETIF Receive function type.

Enumerations

enum esp_netif_dns_type_t

Type of DNS server.

Values:

enumerator ESP_NETIF_DNS_MAIN: DNS main server address

enumerator ESP_NETIF_DNS_BACKUP: DNS backup server address (Wi-Fi STA and Ethernet only)

enumerator ESP_NETIF_DNS_FALLBACK: DNS fallback server address (Wi-Fi STA and Ethernet only)

enumerator ESP_NETIF_DNS_MAX

enum esp_netif_dhcp_status_t

Status of DHCP client or DHCP server.

Values:

enumerator ESP_NETIF_DHCP_INIT: DHCP client/server is in initial state (not yet started)

enumerator ESP_NETIF_DHCP_STARTED: DHCP client/server has been started

enumerator ESP_NETIF_DHCP_STOPPED: DHCP client/server has been stopped

enumerator ESP_NETIF_DHCP_STATUS_MAX

enum esp_netif_dhcp_option_mode_t

Mode for DHCP client or DHCP server option functions.

Values:

enumerator ESP_NETIF_OP_START

enumerator ESP_NETIF_OP_SET: Set option

enumerator ESP_NETIF_OP_GET: Get option

enumerator ESP_NETIF_OP_MAX

enum esp_netif_dhcp_option_id_t

Supported options for DHCP client or DHCP server.

Values:

enumerator ESP_NETIF_SUBNET_MASK: Network mask

enumerator ESP_NETIF_DOMAIN_NAME_SERVER: Domain name server

enumerator ESP_NETIF_ROUTER_SOLICITATION_ADDRESS: Solicitation router address

enumerator ESP_NETIF_REQUESTED_IP_ADDRESS: Request specific IP address

enumerator ESP_NETIF_IP_ADDRESS_LEASE_TIME: Request IP address lease time

enumerator ESP_NETIF_IP_REQUEST_RETRY_TIME: Request IP address retry counter

enumerator ESP_NETIF_VENDOR_CLASS_IDENTIFIER: Vendor Class Identifier of a DHCP client

enumerator ESP_NETIF_VENDOR_SPECIFIC_INFO: Vendor Specific Information of a DHCP server

enumerator ESP_NETIF_CAPTIVEPORTAL_URI: Captive Portal Identification

enum ip_event_t

IP event declarations

Values:

enumerator IP_EVENT_STA_GOT_IP: station got IP from connected AP

enumerator IP_EVENT_STA_LOST_IP: station lost IP and the IP is reset to 0

enumerator IP_EVENT_AP_STAIPASSIGNED: soft-AP assign an IP to a connected station

enumerator IP_EVENT_GOT_IP6: station or ap or ethernet interface v6IP addr is preferred

enumerator IP_EVENT_ETH_GOT_IP: ethernet got IP from connected AP

enumerator IP_EVENT_ETH_LOST_IP: ethernet lost IP and the IP is reset to 0

enumerator IP_EVENT_PPP_GOT_IP: PPP interface got IP

enumerator IP_EVENT_PPP_LOST_IP: PPP interface lost IP

enumerator IP_EVENT_TX_RX: transmitting/receiving data packet

enum esp_netif_tx_rx_direction_t

Values:

enumerator ESP_NETIF_TX

enumerator ESP_NETIF_RX

enum esp_netif_flags

Values:

enumerator ESP_NETIF_DHCP_CLIENT

enumerator ESP_NETIF_DHCP_SERVER

enumerator ESP_NETIF_FLAG_AUTOUP

enumerator ESP_NETIF_FLAG_GARP

enumerator ESP_NETIF_FLAG_EVENT_IP_MODIFIED

enumerator ESP_NETIF_FLAG_IS_PPP

enumerator ESP_NETIF_FLAG_IS_BRIDGE

enumerator ESP_NETIF_FLAG_MLDV6_REPORT

enumerator ESP_NETIF_FLAG_IPV6_AUTOCONFIG_ENABLED

enum esp_netif_ip_event_type

Values:

enumerator ESP_NETIF_IP_EVENT_GOT_IP

enumerator ESP_NETIF_IP_EVENT_LOST_IP

Header File

components/esp_netif/include/esp_netif_ip_addr.h
This header file can be included with:
#include "esp_netif_ip_addr.h"
This header file is a part of the API provided by the esp_netif component. To declare that your component depends on esp_netif, add the following to your CMakeLists.txt:
REQUIRES esp_netif
or
PRIV_REQUIRES esp_netif

Functions

esp_ip6_addr_type_t esp_netif_ip6_get_addr_type(esp_ip6_addr_t *ip6_addr)

Get the IPv6 address type.

参数:: ip6_addr -- [in] IPv6 type
返回:: IPv6 type in form of enum esp_ip6_addr_type_t

static inline void esp_netif_ip_addr_copy(esp_ip_addr_t *dest, const esp_ip_addr_t *src)

Copy IP addresses.

参数:

dest -- [out] destination IP
src -- [in] source IP

Structures

struct esp_ip6_addr

IPv6 address.

Public Members

uint32_t addr[4]: IPv6 address

uint8_t zone: zone ID

struct esp_ip4_addr

IPv4 address.

Public Members

uint32_t addr: IPv4 address

struct _ip_addr

IP address.

Public Members

esp_ip6_addr_t ip6: IPv6 address type

esp_ip4_addr_t ip4: IPv4 address type

union _ip_addr u_addr: IP address union

uint8_t type: ipaddress type

Macros

esp_netif_htonl(x)

esp_netif_ip4_makeu32(a, b, c, d)

ESP_IP6_ADDR_BLOCK1(ip6addr)

ESP_IP6_ADDR_BLOCK2(ip6addr)

ESP_IP6_ADDR_BLOCK3(ip6addr)

ESP_IP6_ADDR_BLOCK4(ip6addr)

ESP_IP6_ADDR_BLOCK5(ip6addr)

ESP_IP6_ADDR_BLOCK6(ip6addr)

ESP_IP6_ADDR_BLOCK7(ip6addr)

ESP_IP6_ADDR_BLOCK8(ip6addr)

IPSTR

esp_ip4_addr_get_byte(ipaddr, idx)

esp_ip4_addr1(ipaddr)

esp_ip4_addr2(ipaddr)

esp_ip4_addr3(ipaddr)

esp_ip4_addr4(ipaddr)

esp_ip4_addr1_16(ipaddr)

esp_ip4_addr2_16(ipaddr)

esp_ip4_addr3_16(ipaddr)

esp_ip4_addr4_16(ipaddr)

IP2STR(ipaddr)

IPV6STR

IPV62STR(ipaddr)

ESP_IPADDR_TYPE_V4

ESP_IPADDR_TYPE_V6

ESP_IPADDR_TYPE_ANY

ESP_IP4TOUINT32(a, b, c, d)

ESP_IP4TOADDR(a, b, c, d)

ESP_IP4ADDR_INIT(a, b, c, d)

ESP_IP6ADDR_INIT(a, b, c, d)

IP4ADDR_STRLEN_MAX

ESP_IP_IS_ANY(addr)

Type Definitions

typedef struct esp_ip4_addr esp_ip4_addr_t

typedef struct esp_ip6_addr esp_ip6_addr_t

typedef struct _ip_addr esp_ip_addr_t: IP address.

Enumerations

enum esp_ip6_addr_type_t

Values:

enumerator ESP_IP6_ADDR_IS_UNKNOWN

enumerator ESP_IP6_ADDR_IS_GLOBAL

enumerator ESP_IP6_ADDR_IS_LINK_LOCAL

enumerator ESP_IP6_ADDR_IS_SITE_LOCAL

enumerator ESP_IP6_ADDR_IS_UNIQUE_LOCAL

enumerator ESP_IP6_ADDR_IS_IPV4_MAPPED_IPV6

Header File

components/esp_netif/include/esp_vfs_l2tap.h
This header file can be included with:
#include "esp_vfs_l2tap.h"
This header file is a part of the API provided by the esp_netif component. To declare that your component depends on esp_netif, add the following to your CMakeLists.txt:
REQUIRES esp_netif
or
PRIV_REQUIRES esp_netif

Functions

esp_err_t esp_vfs_l2tap_intf_register(l2tap_vfs_config_t *config)

Add L2 TAP virtual filesystem driver.

This function must be called prior usage of ESP-NETIF L2 TAP Interface

参数:

config -- L2 TAP virtual filesystem driver configuration. Default base path /dev/net/tap is used when this parameter is NULL.

返回:

esp_err_t

ESP_OK on success

esp_err_t esp_vfs_l2tap_intf_unregister(const char *base_path)

Removes L2 TAP virtual filesystem driver.

参数:

base_path -- Base path to the L2 TAP virtual filesystem driver. Default path /dev/net/tap is used when this parameter is NULL.

返回:

esp_err_t

ESP_OK on success

esp_err_t esp_vfs_l2tap_eth_filter_frame(l2tap_iodriver_handle driver_handle, void *buff, size_t *size, void *info)

Filters received Ethernet L2 frames into L2 TAP infrastructure.

参数:

driver_handle -- handle of driver at which the frame was received
buff -- received L2 frame
size -- input length of the L2 frame which is set to 0 when frame is filtered into L2 TAP
info -- extra information about received Ethernet frame

返回:

esp_err_t

ESP_OK is always returned

Structures

struct l2tap_vfs_config_t

L2Tap VFS config parameters.

Public Members

const char *base_path: vfs base path

struct l2tap_irec_hdr_t

Information Record (IREC)

Public Members

size_t len: Length of the record including header and data

l2tap_irec_type_t type: Type of the record

uint8_t data[]: Records Data aligned to double word

struct l2tap_extended_buff_t

Extended Buffer.

Attention: Use macros when allocating buffer for Information Records and when manipulating with data in the records to ensure proper memory alignment

Public Members

size_t info_recs_len: Length of Information Records buffer

void *info_recs_buff: Buffer holding extended information (IRECs) related to IO frames

size_t buff_len: Length of the actual IO Frame buffer

void *buff: Pointer to the IO Frame buffer

Macros

L2TAP_VFS_DEFAULT_PATH

L2TAP_VFS_CONFIG_DEFAULT()

L2TAP_ALIGN(size)

Macros for operations with Information Records.

Align to double word size to each info record starts aligned in memory even if not aligned info data size is used by previous record. Double word alignment (at 32-bit arch) is needed when accessing double word variables or structs containing double word variables.

L2TAP_IREC_LEN(size)

L2TAP_IREC_SPACE(size)

L2TAP_IREC_FIRST(ext_buff)

L2TAP_IREC_NEXT(ext_buff, curr_rec)

esp_vfs_l2tap_eth_filter(drv_hndl, buf, size)

Wrapper over L2 TAP filter function to ensure backward compatibility.

This macro is provided for backward compatibility with the original esp_vfs_l2tap_eth_filter function. It calls esp_vfs_l2tap_eth_filter_frame() with the info parameter set to NULL, which means L2 TAP features that depend on extra information about the received Ethernet frame (e.g., timestamps) will not work as expected.

备注

For new implementations, it is recommended to use esp_vfs_l2tap_eth_filter_frame() directly to take advantage of the extended functionality.

Type Definitions

typedef void *l2tap_iodriver_handle

Enumerations

enum l2tap_ioctl_opt_t

Values:

enumerator L2TAP_S_RCV_FILTER: Set Ethertype filter, frames with this type to be passed to the file descriptor.

enumerator L2TAP_G_RCV_FILTER: Get current Ethertype filter.

enumerator L2TAP_S_INTF_DEVICE: Bound the file descriptor to a specific Network Interface is identified by its if_key.

enumerator L2TAP_G_INTF_DEVICE: Get the Network Interface if_key the file descriptor is bound to.

enumerator L2TAP_S_DEVICE_DRV_HNDL: Bound the file descriptor to a specific Network Interface identified by IO Driver handle.

enumerator L2TAP_G_DEVICE_DRV_HNDL: Get the Network Interface IO Driver handle the file descriptor is bound to.

enumerator L2TAP_S_TIMESTAMP_EN: Enables the hardware Time Stamping (TS) processing by the file descriptor. TS needs to be supported by hardware and enabled in the IO driver.

enum l2tap_irec_type_t

Information Record (IREC) Header Type indicates expected type of Header Data.

Values:

enumerator L2TAP_IREC_INVALID: Indicate invalid IREC (data is not valid)

enumerator L2TAP_IREC_TIME_STAMP: To retrieve time stamp in struct timespec format

Wi-Fi Default API Reference

Header File

components/esp_wifi/include/esp_wifi_default.h
This header file can be included with:
#include "esp_wifi_default.h"
This header file is a part of the API provided by the esp_wifi component. To declare that your component depends on esp_wifi, add the following to your CMakeLists.txt:
REQUIRES esp_wifi
or
PRIV_REQUIRES esp_wifi

Functions

esp_err_t esp_netif_attach_wifi_station(esp_netif_t *esp_netif)

Attaches wifi station interface to supplied netif.

参数:

esp_netif -- instance to attach the wifi station to

返回:

ESP_OK on success
ESP_FAIL if attach failed

esp_err_t esp_netif_attach_wifi_ap(esp_netif_t *esp_netif)

Attaches wifi soft AP interface to supplied netif.

参数:

esp_netif -- instance to attach the wifi AP to

返回:

ESP_OK on success
ESP_FAIL if attach failed

esp_err_t esp_wifi_set_default_wifi_sta_handlers(void)

Sets default wifi event handlers for STA interface.

返回:

ESP_OK on success, error returned from esp_event_handler_register if failed

esp_err_t esp_wifi_set_default_wifi_ap_handlers(void)

Sets default wifi event handlers for AP interface.

返回:

ESP_OK on success, error returned from esp_event_handler_register if failed

esp_err_t esp_wifi_set_default_wifi_nan_handlers(void)

Sets default wifi event handlers for NAN interface.

返回:

ESP_OK on success, error returned from esp_event_handler_register if failed

esp_err_t esp_wifi_clear_default_wifi_driver_and_handlers(void *esp_netif)

Clears default wifi event handlers for supplied network interface.

参数:

esp_netif -- instance of corresponding if object

返回:

ESP_OK on success, error returned from esp_event_handler_register if failed

esp_netif_t *esp_netif_create_default_wifi_ap(void)

Creates default WIFI AP. In case of any init error this API aborts.

备注

The API creates esp_netif object with default WiFi access point config, attaches the netif to wifi and registers wifi handlers to the default event loop. This API uses assert() to check for potential errors, so it could abort the program. (Note that the default event loop needs to be created prior to calling this API)

返回:: pointer to esp-netif instance

esp_netif_t *esp_netif_create_default_wifi_sta(void)

Creates default WIFI STA. In case of any init error this API aborts.

备注

The API creates esp_netif object with default WiFi station config, attaches the netif to wifi and registers wifi handlers to the default event loop. This API uses assert() to check for potential errors, so it could abort the program. (Note that the default event loop needs to be created prior to calling this API)

返回:: pointer to esp-netif instance

esp_netif_t *esp_netif_create_default_wifi_nan(void)

Creates default WIFI NAN. In case of any init error this API aborts.

备注

The API creates esp_netif object with default WiFi station config, attaches the netif to wifi and registers wifi handlers to the default event loop. (Note that the default event loop needs to be created prior to calling this API)

返回:: pointer to esp-netif instance

void esp_netif_destroy_default_wifi(void *esp_netif)

Destroys default WIFI netif created with esp_netif_create_default_wifi_...() API.

备注

This API unregisters wifi handlers and detaches the created object from the wifi. (this function is a no-operation if esp_netif is NULL)

参数:: esp_netif -- [in] object to detach from WiFi and destroy

esp_netif_t *esp_netif_create_wifi(wifi_interface_t wifi_if, const esp_netif_inherent_config_t *esp_netif_config)

Creates esp_netif WiFi object based on the custom configuration.

Attention: This API DOES NOT register default handlers!

参数:

wifi_if -- [in] type of wifi interface
esp_netif_config -- [in] inherent esp-netif configuration pointer

返回:

pointer to esp-netif instance

esp_err_t esp_netif_create_default_wifi_mesh_netifs(esp_netif_t **p_netif_sta, esp_netif_t **p_netif_ap)

Creates default STA and AP network interfaces for esp-mesh.

Both netifs are almost identical to the default station and softAP, but with DHCP client and server disabled. Please note that the DHCP client is typically enabled only if the device is promoted to a root node.

Returns created interfaces which could be ignored setting parameters to NULL if an application code does not need to save the interface instances for further processing.

参数:

p_netif_sta -- [out] pointer where the resultant STA interface is saved (if non NULL)
p_netif_ap -- [out] pointer where the resultant AP interface is saved (if non NULL)

返回:

ESP_OK on success

此文档对您有帮助吗？

反馈已收到，谢谢！
如果您有其他意见，欢迎填写乐鑫文档反馈表。

我们重视您的反馈。
您可以填写乐鑫文档反馈表告诉我们如何改进该文档。

ESP-NETIF Programmers Manual

Configure IP, Gateway, and DNS

Configure DHCP options

SNTP Service

Basic Mode with Statically Defined Server(s)

Use DHCP-Obtained SNTP Server(s)

Use Both Static and Dynamic Servers

L2 TAP Interface Usage

Initialization

open()

ioctl()

fcntl()

read()

write()

close()

select()

Extended Buffer

Extended Buffer Usage

IP Event: Transmit/Receive Packet

Enabling the Event

Event Registration

Event Data Structure

API Reference

Header File

Header File

Structures

Header File

Structures

Macros

Type Definitions

Enumerations

Header File

Functions

Structures

Macros

Type Definitions

Enumerations

Header File

Functions

Structures

Macros

Type Definitions

Enumerations

Wi-Fi Default API Reference

Header File

Functions

`open()`

`ioctl()`

`fcntl()`

`read()`

`write()`

`close()`

`select()`