/*
* ESPRSSIF MIT License
*
* Copyright (c) 2015 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>
*
* Permission is hereby granted for use on ESPRESSIF SYSTEMS ESP8266 only, in which case,
* it is free of charge, to any person obtaining a copy of this software and associated
* documentation files (the "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the Software is furnished
* to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or
* substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#ifndef __ESPCONN_H__
#define __ESPCONN_H__
#ifdef __cplusplus
extern "C" {
#endif
typedef sint8 err_t;
typedef void *espconn_handle;
/** \defgroup Espconn_APIs Network Espconn APIs
* @brief Network espconn APIs
*
*/
/** @addtogroup Espconn_APIs
* @{
*/
/**
* @brief Connect callback.
*
* Callback which will be called if successful listening (ESP8266 as TCP server)
* or connection (ESP8266 as TCP client) callback, register by espconn_regist_connectcb.
*
* @attention The pointer "void *arg" may be different in different callbacks, please don't
* use this pointer directly to distinguish one from another in multiple connections,
* use remote_ip and remote_port in espconn instead.
*
* @param void *arg : pointer corresponding structure espconn.
*
* @return null
*/
typedef void (* espconn_connect_callback)(void *arg);
/**
* @brief Reconnect callback.
*
* Enter this callback when error occurred, TCP connection broke. This callback is
* registered by espconn_regist_reconcb.
*
* @attention The pointer "void *arg" may be different in different callbacks, please don't
* use this pointer directly to distinguish one from another in multiple connections,
* use remote_ip and remote_port in espconn instead.
*
* @param void *arg : pointer corresponding structure espconn.
* @param sint8 err : error code
* - ESCONN_TIMEOUT - Timeout
* - ESPCONN_ABRT - TCP connection aborted
* - ESPCONN_RST - TCP connection abort
* - ESPCONN_CLSD - TCP connection closed
* - ESPCONN_CONN - TCP connection
* - ESPCONN_HANDSHAKE - TCP SSL handshake fail
* - ESPCONN_PROTO_MSG - SSL application invalid
*
* @return null
*/
typedef void (* espconn_reconnect_callback)(void *arg, sint8 err);
/* Definitions for error constants. */
#define ESPCONN_OK 0 /**< No error, everything OK. */
#define ESPCONN_MEM -1 /**< Out of memory. */
#define ESPCONN_TIMEOUT -3 /**< Timeout. */
#define ESPCONN_RTE -4 /**< Routing problem. */
#define ESPCONN_INPROGRESS -5 /**< Operation in progress. */
#define ESPCONN_MAXNUM -7 /**< Total number exceeds the maximum limitation. */
#define ESPCONN_ABRT -8 /**< Connection aborted. */
#define ESPCONN_RST -9 /**< Connection reset. */
#define ESPCONN_CLSD -10 /**< Connection closed. */
#define ESPCONN_CONN -11 /**< Not connected. */
#define ESPCONN_ARG -12 /**< Illegal argument. */
#define ESPCONN_IF -14 /**< UDP send error. */
#define ESPCONN_ISCONN -15 /**< Already connected. */
/** Protocol family and type of the espconn */
enum espconn_type {
ESPCONN_INVALID = 0, /**< invalid type */
ESPCONN_TCP = 0x10, /**< TCP */
ESPCONN_UDP = 0x20, /**< UDP */
};
/** Current state of the espconn. */
enum espconn_state {
ESPCONN_NONE, /**< idle state, no connection */
ESPCONN_WAIT, /**< ESP8266 is as TCP client, and waiting for connection */
ESPCONN_LISTEN, /**< ESP8266 is as TCP server, and waiting for connection */
ESPCONN_CONNECT, /**< connected */
ESPCONN_WRITE, /**< sending data */
ESPCONN_READ, /**< receiving data */
ESPCONN_CLOSE /**< connection closed */
};
typedef struct _esp_tcp {
int remote_port; /**< remote port of TCP connection */
int local_port; /**< ESP8266's local port of TCP connection */
uint8 local_ip[4]; /**< local IP of ESP8266 */
uint8 remote_ip[4]; /**< remote IP of TCP connection */
espconn_connect_callback connect_callback; /**< connected callback */
espconn_reconnect_callback reconnect_callback; /**< as error handler, the TCP connection broke unexpectedly */
espconn_connect_callback disconnect_callback; /**< disconnected callback */
espconn_connect_callback write_finish_fn; /**< data send by espconn_send has wrote into buffer waiting for sending, or has sent successfully */
} esp_tcp;
typedef struct _esp_udp {
int remote_port; /**< remote port of UDP transmission */
int local_port; /**< ESP8266's local port for UDP transmission */
uint8 local_ip[4]; /**< local IP of ESP8266 */
uint8 remote_ip[4]; /**< remote IP of UDP transmission */
} esp_udp;
typedef struct _remot_info {
enum espconn_state state; /**< state of espconn */
int remote_port; /**< remote port */
uint8 remote_ip[4]; /**< remote IP address */
} remot_info;
/** A callback prototype to inform about events for a espconn */
typedef void (* espconn_recv_callback)(void *arg, char *pdata, unsigned short len);
typedef void (* espconn_sent_callback)(void *arg);
/** A espconn descriptor */
struct espconn {
enum espconn_type type; /**< type of the espconn (TCP or UDP) */
enum espconn_state state; /**< current state of the espconn */
union {
esp_tcp *tcp;
esp_udp *udp;
} proto;
espconn_recv_callback recv_callback; /**< data received callback */
espconn_sent_callback sent_callback; /**< data sent callback */
uint8 link_cnt; /**< link count */
void *reserve; /**< reserved for user data */
};
enum espconn_option {
ESPCONN_START = 0x00, /**< no option, start enum. */
ESPCONN_REUSEADDR = 0x01, /**< free memory after TCP disconnection happen, need not wait 2 minutes. */
ESPCONN_NODELAY = 0x02, /**< disable nagle algorithm during TCP data transmission, quicken the data transmission. */
ESPCONN_COPY = 0x04, /**< enable espconn_regist_write_finish, enter write_finish_callback means that the data espconn_send sending was written into 2920 bytes write-buffer waiting for sending or already sent. */
ESPCONN_KEEPALIVE = 0x08, /**< enable TCP keep alive. */
ESPCONN_END /**< no option, end enum. */
};
enum espconn_level {
ESPCONN_KEEPIDLE, /**< TCP keep-alive interval, unit : second. */
ESPCONN_KEEPINTVL, /**< packet interval during TCP keep-alive, unit : second. */
ESPCONN_KEEPCNT /**< maximum packet retry count of TCP keep-alive. */
};
enum {
ESPCONN_IDLE = 0,
ESPCONN_CLIENT,
ESPCONN_SERVER,
ESPCONN_BOTH,
ESPCONN_MAX
};
/**
* @brief espconn initialization.
*
* @attention Please call this API in user_init, if you need to use espconn functions.
*
* @param null
*
* @return null
*/
void espconn_init(void);
/**
* @brief Connect to a TCP server (ESP8266 acting as TCP client).
*
* @attention If espconn_connect fail, returns non-0 value, there is no connection, so it
* won't enter any espconn callback.
*
* @param struct espconn *espconn : the network connection structure, the espconn to
* listen to the connection
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_RTE - Routing Problem
* - ESPCONN_MEM - Out of memory
* - ESPCONN_ISCONN - Already connected
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn
*/
sint8 espconn_connect(struct espconn *espconn);
/**
* @brief Disconnect a TCP connection.
*
* @attention Don't call this API in any espconn callback. If needed, please use system
* task to trigger espconn_disconnect.
*
* @param struct espconn *espconn : the network connection structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn
*/
sint8 espconn_disconnect(struct espconn *espconn);
/**
* @brief Delete a transmission.
*
* @attention Corresponding creation API :
* - TCP: espconn_accept,
* - UDP: espconn_create
*
* @param struct espconn *espconn : the network connection structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding network according
* to structure espconn
* - ESPCONN_INPROGRESS - the connection is still in progress, please call espconn_disconnect
* to disconnect before delete it.
*/
sint8 espconn_delete(struct espconn *espconn);
/**
* @brief Creates a TCP server (i.e. accepts connections).
*
* @param struct espconn *espconn : the network connection structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
* - ESPCONN_ISCONN - Already connected
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn
*/
sint8 espconn_accept(struct espconn *espconn);
/**
* @brief Create UDP transmission.
*
* @attention Parameter remote_ip and remote_port need to be set, do not set to be 0.
*
* @param struct espconn *espconn : the UDP control block structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
* - ESPCONN_ISCONN - Already connected
* - ESPCONN_ARG - illegal argument, can't find the corresponding UDP transmission
* according to structure espconn
*/
sint8 espconn_create(struct espconn *espconn);
/**
* @brief Get maximum number of how many TCP connections are allowed.
*
* @param null
*
* @return Maximum number of how many TCP connections are allowed.
*/
uint8 espconn_tcp_get_max_con(void);
/**
* @brief Set the maximum number of how many TCP connection is allowed.
*
* @param uint8 num : Maximum number of how many TCP connection is allowed.
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn
*/
sint8 espconn_tcp_set_max_con(uint8 num);
/**
* @brief Get the maximum number of TCP clients which are allowed to connect to ESP8266 TCP server.
*
* @param struct espconn *espconn : the TCP server structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_tcp_get_max_con_allow(struct espconn *espconn);
/**
* @brief Set the maximum number of TCP clients allowed to connect to ESP8266 TCP server.
*
* @param struct espconn *espconn : the TCP server structure
* @param uint8 num : Maximum number of TCP clients which are allowed
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_tcp_set_max_con_allow(struct espconn *espconn, uint8 num);
/**
* @brief Register timeout interval of ESP8266 TCP server.
*
* @attention 1. If timeout is set to 0, timeout will be disable and ESP8266 TCP server will
* not disconnect TCP clients has stopped communication. This usage of timeout=0,
* is deprecated.
* @attention 2. This timeout interval is not very precise, only as reference.
*
* @param struct espconn *espconn : the TCP connection structure
* @param uint32 interval : timeout interval, unit: second, maximum: 7200 seconds
* @param uint8 type_flag : 0, set for all connections; 1, set for a specific connection
* - If the type_flag set to be 0, please call this API after espconn_accept, before listened
* a TCP connection.
* - If the type_flag set to be 1, the first parameter *espconn is the specific connection.
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_time(struct espconn *espconn, uint32 interval, uint8 type_flag);
/**
* @brief Get the information about a TCP connection or UDP transmission.
*
* @param struct espconn *espconn : the network connection structure
* @param remot_info **pcon_info : connect to client info
* @param uint8 typeflags : 0, regular server; 1, ssl server
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding transmission according to
* structure espconn
*/
sint8 espconn_get_connection_info(struct espconn *pespconn, remot_info **pcon_info, uint8 typeflags);
/**
* @brief Register data sent callback which will be called back when data are successfully sent.
*
* @param struct espconn *espconn : the network connection structure
* @param espconn_sent_callback sent_cb : registered callback function which will be called if
* the data is successfully sent
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding transmission according
* to structure espconn
*/
sint8 espconn_regist_sentcb(struct espconn *espconn, espconn_sent_callback sent_cb);
/**
* @brief Register a callback which will be called when all sending TCP data is completely
* write into write-buffer or sent.
*
* Need to call espconn_set_opt to enable write-buffer first.
*
* @attention 1. write-buffer is used to keep TCP data that waiting to be sent, queue number
* of the write-buffer is 8 which means that it can keep 8 packets at most.
* The size of write-buffer is 2920 bytes.
* @attention 2. Users can enable it by using espconn_set_opt.
* @attention 3. Users can call espconn_send to send the next packet in write_finish_callback
* instead of using espconn_sent_callback.
*
* @param struct espconn *espconn : the network connection structure
* @param espconn_connect_callback write_finish_fn : registered callback function which will
* be called if the data is completely write
* into write buffer or sent.
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_write_finish(struct espconn *espconn, espconn_connect_callback write_finish_fn);
/**
* @brief Send data through network.
*
* @attention 1. Please call espconn_send after espconn_sent_callback of the pre-packet.
* @attention 2. If it is a UDP transmission, it is suggested to set espconn->proto.udp->remote_ip
* and remote_port before every calling of espconn_send.
*
* @param struct espconn *espconn : the network connection structure
* @param uint8 *psent : pointer of data
* @param uint16 length : data length
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
* - ESPCONN_ARG - illegal argument, can't find the corresponding network transmission
* according to structure espconn
* - ESPCONN_MAXNUM - buffer of sending data is full
* - ESPCONN_IF - send UDP data fail
*/
sint8 espconn_send(struct espconn *espconn, uint8 *psent, uint16 length);
/**
* @brief Send data through network.
*
* This API is deprecated, please use espconn_send instead.
*
* @attention 1. Please call espconn_sent after espconn_sent_callback of the pre-packet.
* @attention 2. If it is a UDP transmission, it is suggested to set espconn->proto.udp->remote_ip
* and remote_port before every calling of espconn_sent.
*
* @param struct espconn *espconn : the network connection structure
* @param uint8 *psent : pointer of data
* @param uint16 length : data length
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
* - ESPCONN_ARG - illegal argument, can't find the corresponding network transmission
* according to structure espconn
* - ESPCONN_MAXNUM - buffer of sending data is full
* - ESPCONN_IF - send UDP data fail
*/
sint8 espconn_sent(struct espconn *espconn, uint8 *psent, uint16 length);
/**
* @brief Send UDP data.
*
* @param struct espconn *espconn : the UDP structure
* @param uint8 *psent : pointer of data
* @param uint16 length : data length
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
* - ESPCONN_MAXNUM - buffer of sending data is full
* - ESPCONN_IF - send UDP data fail
*/
sint16 espconn_sendto(struct espconn *espconn, uint8 *psent, uint16 length);
/**
* @brief Register connection function which will be called back under successful TCP connection.
*
* @param struct espconn *espconn : the TCP connection structure
* @param espconn_connect_callback connect_cb : registered callback function
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_connectcb(struct espconn *espconn, espconn_connect_callback connect_cb);
/**
* @brief register data receive function which will be called back when data are received.
*
* @param struct espconn *espconn : the network transmission structure
* @param espconn_recv_callback recv_cb : registered callback function
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_recvcb(struct espconn *espconn, espconn_recv_callback recv_cb);
/**
* @brief Register reconnect callback.
*
* @attention espconn_reconnect_callback is more like a network-broken error handler; it handles
* errors that occurs in any phase of the connection.
* For instance, if espconn_send fails, espconn_reconnect_callback will be called
* because the network is broken.
*
* @param struct espconn *espconn : the TCP connection structure
* @param espconn_reconnect_callback recon_cb : registered callback function
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_reconcb(struct espconn *espconn, espconn_reconnect_callback recon_cb);
/**
* @brief Register disconnection function which will be called back under successful TCP
* disconnection.
*
* @param struct espconn *espconn : the TCP connection structure
* @param espconn_connect_callback discon_cb : registered callback function
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_regist_disconcb(struct espconn *espconn, espconn_connect_callback discon_cb);
/**
* @brief Get an available port for network.
*
* @param null
*
* @return Port number.
*/
uint32 espconn_port(void);
/**
* @brief Set option of TCP connection.
*
* @attention In general, we need not call this API. If call espconn_set_opt, please call
* it in espconn_connect_callback.
*
* @param struct espconn *espconn : the TCP connection structure
* @param uint8 opt : option of TCP connection, refer to enum espconn_option
* - bit 0: 1: free memory after TCP disconnection happen need not wait 2 minutes;
* - bit 1: 1: disable nagle algorithm during TCP data transmission, quiken the data transmission.
* - bit 2: 1: enable espconn_regist_write_finish, enter write finish callback means
* the data espconn_send sending was written into 2920 bytes write-buffer
* waiting for sending or already sent.
* - bit 3: 1: enable TCP keep alive
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_set_opt(struct espconn *espconn, uint8 opt);
/**
* @brief Clear option of TCP connection.
*
* @param struct espconn *espconn : the TCP connection structure
* @param uint8 opt : enum espconn_option
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_clear_opt(struct espconn *espconn, uint8 opt);
/**
* @brief Set configuration of TCP keep alive.
*
* @attention In general, we need not call this API. If needed, please call it in
* espconn_connect_callback and call espconn_set_opt to enable keep alive first.
*
* @param struct espconn *espconn : the TCP connection structure
* @param uint8 level : To do TCP keep-alive detection every ESPCONN_KEEPIDLE. If there
* is no response, retry ESPCONN_KEEPCNT times every ESPCONN_KEEPINTVL.
* If still no response, considers it as TCP connection broke, goes
* into espconn_reconnect_callback. Notice, keep alive interval is not
* precise, only for reference, it depends on priority.
* @param void* optarg : value of parameter
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_set_keepalive(struct espconn *espconn, uint8 level, void *optarg);
/**
* @brief Get configuration of TCP keep alive.
*
* @param struct espconn *espconn : the TCP connection structure
* @param uint8 level : enum espconn_level
* @param void* optarg : value of parameter
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection according
* to structure espconn
*/
sint8 espconn_get_keepalive(struct espconn *espconn, uint8 level, void *optarg);
/**
* @brief Callback which is invoked when a hostname is found.
*
* @param const char *name : hostname
* @param ip_addr_t *ipaddr : IP address of the hostname, or to be NULL if the name could
* not be found (or on any other error).
* @param void *callback_arg : callback argument.
*
* @return null
*/
typedef void (*dns_found_callback)(const char *name, ip_addr_t *ipaddr, void *callback_arg);
/**
* @brief DNS function.
*
* Parse a hostname (string) to an IP address.
*
* @param struct espconn *pespconn : espconn to parse a hostname.
* @param const char *hostname : the hostname.
* @param ip_addr_t *addr : IP address.
* @param dns_found_callback found : callback of DNS
*
* @return err_t :
* - ESPCONN_OK - succeed
* - ESPCONN_INPROGRESS - error code : already connected
* - ESPCONN_ARG - error code : illegal argument, can't find network transmission
* according to structure espconn
*/
err_t espconn_gethostbyname(struct espconn *pespconn, const char *hostname, ip_addr_t *addr, dns_found_callback found);
/**
* @brief Join a multicast group.
*
* @attention This API can only be called after the ESP8266 station connects to a router.
*
* @param ip_addr_t *host_ip : IP of UDP host
* @param ip_addr_t *multicast_ip : IP of multicast group
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
*/
sint8 espconn_igmp_join(ip_addr_t *host_ip, ip_addr_t *multicast_ip);
/**
* @brief Leave a multicast group.
*
* @attention This API can only be called after the ESP8266 station connects to a router.
*
* @param ip_addr_t *host_ip : IP of UDP host
* @param ip_addr_t *multicast_ip : IP of multicast group
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_MEM - Out of memory
*/
sint8 espconn_igmp_leave(ip_addr_t *host_ip, ip_addr_t *multicast_ip);
/**
* @brief Puts in a request to block the TCP receive function.
*
* @attention The function does not act immediately; we recommend calling it while
* reserving 5*1460 bytes of memory. This API can be called more than once.
*
* @param struct espconn *espconn : corresponding TCP connection structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn.
*/
sint8 espconn_recv_hold(struct espconn *pespconn);
/**
* @brief Unblock TCP receiving data (i.e. undo espconn_recv_hold).
*
* @attention This API takes effect immediately.
*
* @param struct espconn *espconn : corresponding TCP connection structure
*
* @return 0 : succeed
* @return Non-0 : error code
* - ESPCONN_ARG - illegal argument, can't find the corresponding TCP connection
* according to structure espconn.
*/
sint8 espconn_recv_unhold(struct espconn *pespconn);
/**
* @brief Set default DNS server. Two DNS server is allowed to be set.
*
* @attention Only if ESP8266 DHCP client is disabled (wifi_station_dhcpc_stop),
* this API can be used.
*
* @param char numdns : DNS server ID, 0 or 1
* @param ip_addr_t *dnsserver : DNS server IP
*
* @return null
*/
void espconn_dns_setserver(char numdns, ip_addr_t *dnsserver);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif