Events and callback functions¶
Library uses events to notify application layer for (possible, but not limited to) unexpected events. This concept is used aswell for commands with longer executing time, such as scanning access points or when application starts new connection as client mode.
There are 3 types of events/callbacks available:
Global event callback function, assigned when initializing library
Connection specific event callback function, to process only events related to connection, such as connection error, data send, data receive, connection closed
API function call based event callback function
Every callback is always called from protected area of middleware (when exclusing access is granted to single thread only),
and it can be called from one of these 3 threads:
Producing thread
Processing thread
Input thread, when
LWESP_CFG_INPUT_USE_PROCESSis enabled andlwesp_input_process()function is called
Tip
Check Inter thread communication for more details about Producing and Processing thread.
Global event callback¶
Global event callback function is assigned at library initialization. It is used by the application to receive any kind of event, except the one related to connection:
ESP station successfully connected to access point
ESP physical device reset has been detected
Restore operation finished
New station has connected to access point
and many more..
Tip
Check Event management section for different kind of events
By default, global event function is single function.
If the application tries to split different events with different callback functions,
it is possible to do so by using lwesp_evt_register() function to register a new,
custom, event function.
Tip
Implementation of Netconn API leverages lwesp_evt_register() to
receive event when station disconnected from wifi access point.
Check its source file for actual implementation.
Netconn API module actual implementation¶
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* \file lwesp_netconn.c
* \brief API functions for sequential calls
*/
/*
* Copyright (c) 2020 Tilen MAJERLE
*
* Permission is hereby granted, 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.
*
* This file is part of LwESP - Lightweight ESP-AT parser library.
*
* Author: Tilen MAJERLE <tilen@majerle.eu>
* Version: v1.0.0
*/
#include "lwesp/lwesp_netconn.h"
#include "lwesp/lwesp_private.h"
#include "lwesp/lwesp_conn.h"
#include "lwesp/lwesp_mem.h"
#if LWESP_CFG_NETCONN || __DOXYGEN__
/* Check conditions */
#if LWESP_CFG_NETCONN_RECEIVE_QUEUE_LEN < 2
#error "LWESP_CFG_NETCONN_RECEIVE_QUEUE_LEN must be greater or equal to 2"
#endif /* LWESP_CFG_NETCONN_RECEIVE_QUEUE_LEN < 2 */
#if LWESP_CFG_NETCONN_ACCEPT_QUEUE_LEN < 2
#error "LWESP_CFG_NETCONN_ACCEPT_QUEUE_LEN must be greater or equal to 2"
#endif /* LWESP_CFG_NETCONN_ACCEPT_QUEUE_LEN < 2 */
/**
* \brief Sequential API structure
*/
typedef struct lwesp_netconn {
struct lwesp_netconn* next; /*!< Linked list entry */
lwesp_netconn_type_t type; /*!< Netconn type */
lwesp_port_t listen_port; /*!< Port on which we are listening */
size_t rcv_packets; /*!< Number of received packets so far on this connection */
lwesp_conn_p conn; /*!< Pointer to actual connection */
lwesp_sys_mbox_t mbox_accept; /*!< List of active connections waiting to be processed */
lwesp_sys_mbox_t mbox_receive; /*!< Message queue for receive mbox */
size_t mbox_receive_entries; /*!< Number of entries written to receive mbox */
lwesp_linbuff_t buff; /*!< Linear buffer structure */
uint16_t conn_timeout; /*!< Connection timeout in units of seconds when
netconn is in server (listen) mode.
Connection will be automatically closed if there is no
data exchange in time. Set to `0` when timeout feature is disabled. */
#if LWESP_CFG_NETCONN_RECEIVE_TIMEOUT || __DOXYGEN__
uint32_t rcv_timeout; /*!< Receive timeout in unit of milliseconds */
#endif
} lwesp_netconn_t;
static uint8_t recv_closed = 0xFF, recv_not_present = 0xFF;
static lwesp_netconn_t* listen_api; /*!< Main connection in listening mode */
static lwesp_netconn_t* netconn_list; /*!< Linked list of netconn entries */
/**
* \brief Flush all mboxes and clear possible used memories
* \param[in] nc: Pointer to netconn to flush
* \param[in] protect: Set to 1 to protect against multi-thread access
*/
static void
flush_mboxes(lwesp_netconn_t* nc, uint8_t protect) {
lwesp_pbuf_p pbuf;
lwesp_netconn_t* new_nc;
if (protect) {
lwesp_core_lock();
}
if (lwesp_sys_mbox_isvalid(&nc->mbox_receive)) {
while (lwesp_sys_mbox_getnow(&nc->mbox_receive, (void**)&pbuf)) {
if (nc->mbox_receive_entries > 0) {
--nc->mbox_receive_entries;
}
if (pbuf != NULL && (uint8_t*)pbuf != (uint8_t*)&recv_closed) {
lwesp_pbuf_free(pbuf); /* Free received data buffers */
}
}
lwesp_sys_mbox_delete(&nc->mbox_receive); /* Delete message queue */
lwesp_sys_mbox_invalid(&nc->mbox_receive); /* Invalid handle */
}
if (lwesp_sys_mbox_isvalid(&nc->mbox_accept)) {
while (lwesp_sys_mbox_getnow(&nc->mbox_accept, (void**)&new_nc)) {
if (new_nc != NULL
&& (uint8_t*)new_nc != (uint8_t*)&recv_closed
&& (uint8_t*)new_nc != (uint8_t*)&recv_not_present) {
lwesp_netconn_close(new_nc); /* Close netconn connection */
}
}
lwesp_sys_mbox_delete(&nc->mbox_accept);/* Delete message queue */
lwesp_sys_mbox_invalid(&nc->mbox_accept); /* Invalid handle */
}
if (protect) {
lwesp_core_unlock();
}
}
/**
* \brief Callback function for every server connection
* \param[in] evt: Pointer to callback structure
* \return Member of \ref lwespr_t enumeration
*/
static lwespr_t
netconn_evt(lwesp_evt_t* evt) {
lwesp_conn_p conn;
lwesp_netconn_t* nc = NULL;
uint8_t close = 0;
conn = lwesp_conn_get_from_evt(evt); /* Get connection from event */
switch (lwesp_evt_get_type(evt)) {
/*
* A new connection has been active
* and should be handled by netconn API
*/
case LWESP_EVT_CONN_ACTIVE: { /* A new connection active is active */
if (lwesp_conn_is_client(conn)) { /* Was connection started by us? */
nc = lwesp_conn_get_arg(conn); /* Argument should be already set */
if (nc != NULL) {
nc->conn = conn; /* Save actual connection */
} else {
close = 1; /* Close this connection, invalid netconn */
}
/* Is the connection server type and we have known listening API? */
} else if (lwesp_conn_is_server(conn) && listen_api != NULL) {
/*
* Create a new netconn structure
* and set it as connection argument.
*/
nc = lwesp_netconn_new(LWESP_NETCONN_TYPE_TCP); /* Create new API */
LWESP_DEBUGW(LWESP_CFG_DBG_NETCONN | LWESP_DBG_TYPE_TRACE | LWESP_DBG_LVL_WARNING,
nc == NULL, "[NETCONN] Cannot create new structure for incoming server connection!\r\n");
if (nc != NULL) {
nc->conn = conn; /* Set connection handle */
lwesp_conn_set_arg(conn, nc); /* Set argument for connection */
/*
* In case there is no listening connection,
* simply close the connection
*/
if (!lwesp_sys_mbox_isvalid(&listen_api->mbox_accept)
|| !lwesp_sys_mbox_putnow(&listen_api->mbox_accept, nc)) {
close = 1;
}
} else {
close = 1;
}
} else {
LWESP_DEBUGW(LWESP_CFG_DBG_NETCONN | LWESP_DBG_TYPE_TRACE | LWESP_DBG_LVL_WARNING, listen_api == NULL,
"[NETCONN] Closing connection as there is no listening API in netconn!\r\n");
close = 1; /* Close the connection at this point */
}
/* Decide if some events want to close the connection */
if (close) {
if (nc != NULL) {
lwesp_conn_set_arg(conn, NULL); /* Reset argument */
lwesp_netconn_delete(nc); /* Free memory for API */
}
lwesp_conn_close(conn, 0); /* Close the connection */
close = 0;
}
break;
}
/*
* We have a new data received which
* should have netconn structure as argument
*/
case LWESP_EVT_CONN_RECV: {
lwesp_pbuf_p pbuf;
nc = lwesp_conn_get_arg(conn); /* Get API from connection */
pbuf = lwesp_evt_conn_recv_get_buff(evt); /* Get received buff */
#if !LWESP_CFG_CONN_MANUAL_TCP_RECEIVE
lwesp_conn_recved(conn, pbuf); /* Notify stack about received data */
#endif /* !LWESP_CFG_CONN_MANUAL_TCP_RECEIVE */
lwesp_pbuf_ref(pbuf); /* Increase reference counter */
if (nc == NULL || !lwesp_sys_mbox_isvalid(&nc->mbox_receive)
|| !lwesp_sys_mbox_putnow(&nc->mbox_receive, pbuf)) {
LWESP_DEBUGF(LWESP_CFG_DBG_NETCONN,
"[NETCONN] Ignoring more data for receive!\r\n");
lwesp_pbuf_free(pbuf); /* Free pbuf */
return lwespOKIGNOREMORE; /* Return OK to free the memory and ignore further data */
}
++nc->mbox_receive_entries; /* Increase number of packets in receive mbox */
#if LWESP_CFG_CONN_MANUAL_TCP_RECEIVE
/* Check against 1 less to still allow potential close event to be written to queue */
if (nc->mbox_receive_entries >= (LWESP_CFG_NETCONN_RECEIVE_QUEUE_LEN - 1)) {
conn->status.f.receive_blocked = 1; /* Block reading more data */
}
#endif /* LWESP_CFG_CONN_MANUAL_TCP_RECEIVE */
++nc->rcv_packets; /* Increase number of packets received */
LWESP_DEBUGF(LWESP_CFG_DBG_NETCONN | LWESP_DBG_TYPE_TRACE,
"[NETCONN] Received pbuf contains %d bytes. Handle written to receive mbox\r\n",
(int)lwesp_pbuf_length(pbuf, 0));
break;
}
/* Connection was just closed */
case LWESP_EVT_CONN_CLOSE: {
nc = lwesp_conn_get_arg(conn); /* Get API from connection */
/*
* In case we have a netconn available,
* simply write pointer to received variable to indicate closed state
*/
if (nc != NULL && lwesp_sys_mbox_isvalid(&nc->mbox_receive)) {
if (lwesp_sys_mbox_putnow(&nc->mbox_receive, (void*)&recv_closed)) {
++nc->mbox_receive_entries;
}
}
break;
}
default:
return lwespERR;
}
return lwespOK;
}
/**
* \brief Global event callback function
* \param[in] evt: Callback information and data
* \return \ref lwespOK on success, member of \ref lwespr_t otherwise
*/
static lwespr_t
lwesp_evt(lwesp_evt_t* evt) {
switch (lwesp_evt_get_type(evt)) {
case LWESP_EVT_WIFI_DISCONNECTED: { /* Wifi disconnected event */
if (listen_api != NULL) { /* Check if listen API active */
lwesp_sys_mbox_putnow(&listen_api->mbox_accept, &recv_closed);
}
break;
}
case LWESP_EVT_DEVICE_PRESENT: { /* Device present event */
if (listen_api != NULL && !lwesp_device_is_present()) { /* Check if device present */
lwesp_sys_mbox_putnow(&listen_api->mbox_accept, &recv_not_present);
}
}
default:
break;
}
return lwespOK;
}
/**
* \brief Create new netconn connection
* \param[in] type: Netconn connection type
* \return New netconn connection on success, `NULL` otherwise
*/
lwesp_netconn_p
lwesp_netconn_new(lwesp_netconn_type_t type) {
lwesp_netconn_t* a;
static uint8_t first = 1;
/* Register only once! */
lwesp_core_lock();
if (first) {
first = 0;
lwesp_evt_register(lwesp_evt); /* Register global event function */
}
lwesp_core_unlock();
a = lwesp_mem_calloc(1, sizeof(*a)); /* Allocate memory for core object */
if (a != NULL) {
a->type = type; /* Save netconn type */
a->conn_timeout = 0; /* Default connection timeout */
if (!lwesp_sys_mbox_create(&a->mbox_accept, LWESP_CFG_NETCONN_ACCEPT_QUEUE_LEN)) { /* Allocate memory for accepting message box */
LWESP_DEBUGF(LWESP_CFG_DBG_NETCONN | LWESP_DBG_TYPE_TRACE | LWESP_DBG_LVL_DANGER,
"[NETCONN] Cannot create accept MBOX\r\n");
goto free_ret;
}
if (!lwesp_sys_mbox_create(&a->mbox_receive, LWESP_CFG_NETCONN_RECEIVE_QUEUE_LEN)) {/* Allocate memory for receiving message box */
LWESP_DEBUGF(LWESP_CFG_DBG_NETCONN | LWESP_DBG_TYPE_TRACE | LWESP_DBG_LVL_DANGER,
"[NETCONN] Cannot create receive MBOX\r\n");
goto free_ret;
}
lwesp_core_lock();
if (netconn_list == NULL) { /* Add new netconn to the existing list */
netconn_list = a;
} else {
a->next = netconn_list; /* Add it to beginning of the list */
netconn_list = a;
}
lwesp_core_unlock();
}
return a;
free_ret:
if (lwesp_sys_mbox_isvalid(&a->mbox_accept)) {
lwesp_sys_mbox_delete(&a->mbox_accept);
lwesp_sys_mbox_invalid(&a->mbox_accept);
}
if (lwesp_sys_mbox_isvalid(&a->mbox_receive)) {
lwesp_sys_mbox_delete(&a->mbox_receive);
lwesp_sys_mbox_invalid(&a->mbox_receive);
}
if (a != NULL) {
lwesp_mem_free_s((void**)&a);
}
return NULL;
}
/**
* \brief Delete netconn connection
* \param[in] nc: Netconn handle
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_delete(lwesp_netconn_p nc) {
LWESP_ASSERT("netconn != NULL", nc != NULL);
lwesp_core_lock();
flush_mboxes(nc, 0); /* Clear mboxes */
/* Stop listening on netconn */
if (nc == listen_api) {
listen_api = NULL;
lwesp_core_unlock();
lwesp_set_server(0, nc->listen_port, 0, 0, NULL, NULL, NULL, 1);
lwesp_core_lock();
}
/* Remove netconn from linkedlist */
if (nc == netconn_list) {
netconn_list = netconn_list->next; /* Remove first from linked list */
} else if (netconn_list != NULL) {
lwesp_netconn_p tmp, prev;
/* Find element on the list */
for (prev = netconn_list, tmp = netconn_list->next;
tmp != NULL; prev = tmp, tmp = tmp->next) {
if (nc == tmp) {
prev->next = tmp->next; /* Remove tmp from linked list */
break;
}
}
}
lwesp_core_unlock();
lwesp_mem_free_s((void**)&nc);
return lwespOK;
}
/**
* \brief Connect to server as client
* \param[in] nc: Netconn handle
* \param[in] host: Pointer to host, such as domain name or IP address in string format
* \param[in] port: Target port to use
* \return \ref lwespOK if successfully connected, member of \ref lwespr_t otherwise
*/
lwespr_t
lwesp_netconn_connect(lwesp_netconn_p nc, const char* host, lwesp_port_t port) {
lwespr_t res;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("host != NULL", host != NULL);
LWESP_ASSERT("port > 0", port > 0);
/*
* Start a new connection as client and:
*
* - Set current netconn structure as argument
* - Set netconn callback function for connection management
* - Start connection in blocking mode
*/
res = lwesp_conn_start(NULL, (lwesp_conn_type_t)nc->type, host, port, nc, netconn_evt, 1);
return res;
}
/**
* \brief Connect to server as client, allow keep-alive option
* \param[in] nc: Netconn handle
* \param[in] host: Pointer to host, such as domain name or IP address in string format
* \param[in] port: Target port to use
* \param[in] keep_alive: Keep alive period seconds
* \param[in] local_ip: Local ip in connected command
* \param[in] local_port: Local port address
* \param[in] mode: UDP mode
* \return \ref lwespOK if successfully connected, member of \ref lwespr_t otherwise
*/
lwespr_t
lwesp_netconn_connect_ex(lwesp_netconn_p nc, const char* host, lwesp_port_t port, uint16_t keep_alive, const char* local_ip, lwesp_port_t local_port, uint8_t mode) {
lwesp_conn_start_t cs = {0};
lwespr_t res;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("host != NULL", host != NULL);
LWESP_ASSERT("port > 0", port > 0);
/*
* Start a new connection as client and:
*
* - Set current netconn structure as argument
* - Set netconn callback function for connection management
* - Start connection in blocking mode
*/
cs.type = nc->type;
cs.remote_host = host;
cs.remote_port = port;
cs.local_ip = local_ip;
if (nc->type == LWESP_NETCONN_TYPE_TCP || nc->type == LWESP_NETCONN_TYPE_SSL) {
cs.ext.tcp_ssl.keep_alive = keep_alive;
} else {
cs.ext.udp.local_port = local_port;
cs.ext.udp.mode = mode;
}
res = lwesp_conn_startex(NULL, &cs, nc, netconn_evt, 1);
return res;
}
/**
* \brief Bind a connection to specific port, can be only used for server connections
* \param[in] nc: Netconn handle
* \param[in] port: Port used to bind a connection to
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_bind(lwesp_netconn_p nc, lwesp_port_t port) {
lwespr_t res = lwespOK;
LWESP_ASSERT("nc != NULL", nc != NULL);
/*
* Protection is not needed as it is expected
* that this function is called only from single
* thread for single netconn connection,
* thus it is considered reentrant
*/
nc->listen_port = port;
return res;
}
/**
* \brief Set timeout value in units of seconds when connection is in listening mode
* If new connection is accepted, it will be automatically closed after `seconds` elapsed
* without any data exchange.
* \note Call this function before you put connection to listen mode with \ref lwesp_netconn_listen
* \param[in] nc: Netconn handle used for listen mode
* \param[in] timeout: Time in units of seconds. Set to `0` to disable timeout feature
* \return \ref lwespOK on success, member of \ref lwespr_t otherwise
*/
lwespr_t
lwesp_netconn_set_listen_conn_timeout(lwesp_netconn_p nc, uint16_t timeout) {
lwespr_t res = lwespOK;
LWESP_ASSERT("nc != NULL", nc != NULL);
/*
* Protection is not needed as it is expected
* that this function is called only from single
* thread for single netconn connection,
* thus it is reentrant in this case
*/
nc->conn_timeout = timeout;
return res;
}
/**
* \brief Listen on previously binded connection
* \param[in] nc: Netconn handle used to listen for new connections
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_listen(lwesp_netconn_p nc) {
return lwesp_netconn_listen_with_max_conn(nc, LWESP_CFG_MAX_CONNS);
}
/**
* \brief Listen on previously binded connection with max allowed connections at a time
* \param[in] nc: Netconn handle used to listen for new connections
* \param[in] max_connections: Maximal number of connections server can accept at a time
* This parameter may not be larger than \ref LWESP_CFG_MAX_CONNS
* \return \ref lwespOK on success, member of \ref lwespr_t otherwise
*/
lwespr_t
lwesp_netconn_listen_with_max_conn(lwesp_netconn_p nc, uint16_t max_connections) {
lwespr_t res;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->type must be TCP", nc->type == LWESP_NETCONN_TYPE_TCP);
/* Enable server on port and set default netconn callback */
if ((res = lwesp_set_server(1, nc->listen_port,
LWESP_U16(LWESP_MIN(max_connections, LWESP_CFG_MAX_CONNS)),
nc->conn_timeout, netconn_evt, NULL, NULL, 1)) == lwespOK) {
lwesp_core_lock();
listen_api = nc; /* Set current main API in listening state */
lwesp_core_unlock();
}
return res;
}
/**
* \brief Accept a new connection
* \param[in] nc: Netconn handle used as base connection to accept new clients
* \param[out] client: Pointer to netconn handle to save new connection to
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_accept(lwesp_netconn_p nc, lwesp_netconn_p* client) {
lwesp_netconn_t* tmp;
uint32_t time;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("client != NULL", client != NULL);
LWESP_ASSERT("nc->type must be TCP", nc->type == LWESP_NETCONN_TYPE_TCP);
LWESP_ASSERT("nc == listen_api", nc == listen_api);
*client = NULL;
time = lwesp_sys_mbox_get(&nc->mbox_accept, (void**)&tmp, 0);
if (time == LWESP_SYS_TIMEOUT) {
return lwespTIMEOUT;
}
if ((uint8_t*)tmp == (uint8_t*)&recv_closed) {
lwesp_core_lock();
listen_api = NULL; /* Disable listening at this point */
lwesp_core_unlock();
return lwespERRWIFINOTCONNECTED; /* Wifi disconnected */
} else if ((uint8_t*)tmp == (uint8_t*)&recv_not_present) {
lwesp_core_lock();
listen_api = NULL; /* Disable listening at this point */
lwesp_core_unlock();
return lwespERRNODEVICE; /* Device not present */
}
*client = tmp; /* Set new pointer */
return lwespOK; /* We have a new connection */
}
/**
* \brief Write data to connection output buffers
* \note This function may only be used on TCP or SSL connections
* \param[in] nc: Netconn handle used to write data to
* \param[in] data: Pointer to data to write
* \param[in] btw: Number of bytes to write
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_write(lwesp_netconn_p nc, const void* data, size_t btw) {
size_t len, sent;
const uint8_t* d = data;
lwespr_t res;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->type must be TCP or SSL", nc->type == LWESP_NETCONN_TYPE_TCP || nc->type == LWESP_NETCONN_TYPE_SSL);
LWESP_ASSERT("nc->conn must be active", lwesp_conn_is_active(nc->conn));
/*
* Several steps are done in write process
*
* 1. Check if buffer is set and check if there is something to write to it.
* 1. In case buffer will be full after copy, send it and free memory.
* 2. Check how many bytes we can write directly without need to copy
* 3. Try to allocate a new buffer and copy remaining input data to it
* 4. In case buffer allocation fails, send data directly (may have impact on speed and effectivenes)
*/
/* Step 1 */
if (nc->buff.buff != NULL) { /* Is there a write buffer ready to accept more data? */
len = LWESP_MIN(nc->buff.len - nc->buff.ptr, btw); /* Get number of bytes we can write to buffer */
if (len > 0) {
LWESP_MEMCPY(&nc->buff.buff[nc->buff.ptr], data, len); /* Copy memory to temporary write buffer */
d += len;
nc->buff.ptr += len;
btw -= len;
}
/* Step 1.1 */
if (nc->buff.ptr == nc->buff.len) {
res = lwesp_conn_send(nc->conn, nc->buff.buff, nc->buff.len, &sent, 1);
lwesp_mem_free_s((void**)&nc->buff.buff);
if (res != lwespOK) {
return res;
}
} else {
return lwespOK; /* Buffer is not full yet */
}
}
/* Step 2 */
if (btw >= LWESP_CFG_CONN_MAX_DATA_LEN) {
size_t rem;
rem = btw % LWESP_CFG_CONN_MAX_DATA_LEN;/* Get remaining bytes for max data length */
res = lwesp_conn_send(nc->conn, d, btw - rem, &sent, 1);/* Write data directly */
if (res != lwespOK) {
return res;
}
d += sent; /* Advance in data pointer */
btw -= sent; /* Decrease remaining data to send */
}
if (btw == 0) { /* Sent everything? */
return lwespOK;
}
/* Step 3 */
if (nc->buff.buff == NULL) { /* Check if we should allocate a new buffer */
nc->buff.buff = lwesp_mem_malloc(sizeof(*nc->buff.buff) * LWESP_CFG_CONN_MAX_DATA_LEN);
nc->buff.len = LWESP_CFG_CONN_MAX_DATA_LEN; /* Save buffer length */
nc->buff.ptr = 0; /* Save buffer pointer */
}
/* Step 4 */
if (nc->buff.buff != NULL) { /* Memory available? */
LWESP_MEMCPY(&nc->buff.buff[nc->buff.ptr], d, btw); /* Copy data to buffer */
nc->buff.ptr += btw;
} else { /* Still no memory available? */
return lwesp_conn_send(nc->conn, data, btw, NULL, 1); /* Simply send directly blocking */
}
return lwespOK;
}
/**
* \brief Flush buffered data on netconn TCP/SSL connection
* \note This function may only be used on TCP/SSL connection
* \param[in] nc: Netconn handle to flush data
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_flush(lwesp_netconn_p nc) {
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->type must be TCP or SSL", nc->type == LWESP_NETCONN_TYPE_TCP || nc->type == LWESP_NETCONN_TYPE_SSL);
LWESP_ASSERT("nc->conn must be active", lwesp_conn_is_active(nc->conn));
/*
* In case we have data in write buffer,
* flush them out to network
*/
if (nc->buff.buff != NULL) { /* Check remaining data */
if (nc->buff.ptr > 0) { /* Do we have data in current buffer? */
lwesp_conn_send(nc->conn, nc->buff.buff, nc->buff.ptr, NULL, 1);/* Send data */
}
lwesp_mem_free_s((void**)&nc->buff.buff);
}
return lwespOK;
}
/**
* \brief Send data on UDP connection to default IP and port
* \param[in] nc: Netconn handle used to send
* \param[in] data: Pointer to data to write
* \param[in] btw: Number of bytes to write
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_send(lwesp_netconn_p nc, const void* data, size_t btw) {
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->type must be UDP", nc->type == LWESP_NETCONN_TYPE_UDP);
LWESP_ASSERT("nc->conn must be active", lwesp_conn_is_active(nc->conn));
return lwesp_conn_send(nc->conn, data, btw, NULL, 1);
}
/**
* \brief Send data on UDP connection to specific IP and port
* \note Use this function in case of UDP type netconn
* \param[in] nc: Netconn handle used to send
* \param[in] ip: Pointer to IP address
* \param[in] port: Port number used to send data
* \param[in] data: Pointer to data to write
* \param[in] btw: Number of bytes to write
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_sendto(lwesp_netconn_p nc, const lwesp_ip_t* ip, lwesp_port_t port, const void* data, size_t btw) {
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->type must be UDP", nc->type == LWESP_NETCONN_TYPE_UDP);
LWESP_ASSERT("nc->conn must be active", lwesp_conn_is_active(nc->conn));
return lwesp_conn_sendto(nc->conn, ip, port, data, btw, NULL, 1);
}
/**
* \brief Receive data from connection
* \param[in] nc: Netconn handle used to receive from
* \param[in] pbuf: Pointer to pointer to save new receive buffer to.
* When function returns, user must check for valid pbuf value `pbuf != NULL`
* \return \ref lwespOK when new data ready
* \return \ref lwespCLOSED when connection closed by remote side
* \return \ref lwespTIMEOUT when receive timeout occurs
* \return Any other member of \ref lwespr_t otherwise
*/
lwespr_t
lwesp_netconn_receive(lwesp_netconn_p nc, lwesp_pbuf_p* pbuf) {
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("pbuf != NULL", pbuf != NULL);
*pbuf = NULL;
#if LWESP_CFG_NETCONN_RECEIVE_TIMEOUT
/*
* Wait for new received data for up to specific timeout
* or throw error for timeout notification
*/
if (nc->rcv_timeout == LWESP_NETCONN_RECEIVE_NO_WAIT) {
if (!lwesp_sys_mbox_getnow(&nc->mbox_receive, (void**)pbuf)) {
return lwespTIMEOUT;
}
} else if (lwesp_sys_mbox_get(&nc->mbox_receive, (void**)pbuf, nc->rcv_timeout) == LWESP_SYS_TIMEOUT) {
return lwespTIMEOUT;
}
#else /* LWESP_CFG_NETCONN_RECEIVE_TIMEOUT */
/* Forever wait for new receive packet */
lwesp_sys_mbox_get(&nc->mbox_receive, (void**)pbuf, 0);
#endif /* !LWESP_CFG_NETCONN_RECEIVE_TIMEOUT */
lwesp_core_lock();
if (nc->mbox_receive_entries > 0) {
--nc->mbox_receive_entries;
}
lwesp_core_unlock();
/* Check if connection closed */
if ((uint8_t*)(*pbuf) == (uint8_t*)&recv_closed) {
*pbuf = NULL; /* Reset pbuf */
return lwespCLOSED;
}
#if LWESP_CFG_CONN_MANUAL_TCP_RECEIVE
else {
lwesp_core_lock();
nc->conn->status.f.receive_blocked = 0; /* Resume reading more data */
lwesp_conn_recved(nc->conn, *pbuf); /* Notify stack about received data */
lwesp_core_unlock();
}
#endif /* LWESP_CFG_CONN_MANUAL_TCP_RECEIVE */
return lwespOK; /* We have data available */
}
/**
* \brief Close a netconn connection
* \param[in] nc: Netconn handle to close
* \return \ref lwespOK on success, member of \ref lwespr_t enumeration otherwise
*/
lwespr_t
lwesp_netconn_close(lwesp_netconn_p nc) {
lwesp_conn_p conn;
LWESP_ASSERT("nc != NULL", nc != NULL);
LWESP_ASSERT("nc->conn != NULL", nc->conn != NULL);
LWESP_ASSERT("nc->conn must be active", lwesp_conn_is_active(nc->conn));
lwesp_netconn_flush(nc); /* Flush data and ignore result */
conn = nc->conn;
nc->conn = NULL;
lwesp_conn_set_arg(conn, NULL); /* Reset argument */
lwesp_conn_close(conn, 1); /* Close the connection */
flush_mboxes(nc, 1); /* Flush message queues */
return lwespOK;
}
/**
* \brief Get connection number used for netconn
* \param[in] nc: Netconn handle
* \return `-1` on failure, connection number between `0` and \ref LWESP_CFG_MAX_CONNS otherwise
*/
int8_t
lwesp_netconn_get_connnum(lwesp_netconn_p nc) {
if (nc != NULL && nc->conn != NULL) {
return lwesp_conn_getnum(nc->conn);
}
return -1;
}
#if LWESP_CFG_NETCONN_RECEIVE_TIMEOUT || __DOXYGEN__
/**
* \brief Set timeout value for receiving data.
*
* When enabled, \ref lwesp_netconn_receive will only block for up to
* `timeout` value and will return if no new data within this time
*
* \param[in] nc: Netconn handle
* \param[in] timeout: Timeout in units of milliseconds.
* Set to `0` to disable timeout feature
* Set to `> 0` to set maximum milliseconds to wait before timeout
* Set to \ref LWESP_NETCONN_RECEIVE_NO_WAIT to enable non-blocking receive
*/
void
lwesp_netconn_set_receive_timeout(lwesp_netconn_p nc, uint32_t timeout) {
nc->rcv_timeout = timeout;
}
/**
* \brief Get netconn receive timeout value
* \param[in] nc: Netconn handle
* \return Timeout in units of milliseconds.
* If value is `0`, timeout is disabled (wait forever)
*/
uint32_t
lwesp_netconn_get_receive_timeout(lwesp_netconn_p nc) {
return nc->rcv_timeout;
}
#endif /* LWESP_CFG_NETCONN_RECEIVE_TIMEOUT || __DOXYGEN__ */
/**
* \brief Get netconn connection handle
* \param[in] nc: Netconn handle
* \return ESP connection handle
*/
lwesp_conn_p
lwesp_netconn_get_conn(lwesp_netconn_p nc) {
return nc->conn;
}
#endif /* LWESP_CFG_NETCONN || __DOXYGEN__ */
|
Connection specific event¶
This events are subset of global event callback. They work exactly the same way as global, but only receive events related to connections.
Tip
Connection related events start with LWESP_EVT_CONN_*, such as LWESP_EVT_CONN_RECV.
Check Event management for list of all connection events.
Connection events callback function is set for 2 cases:
Each client (when application starts connection) sets event callback function when trying to connect with
lwesp_conn_start()functionApplication sets global event callback function when enabling server mode with
lwesp_set_server()function
An example of client with its dedicated event callback function¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | #include "client.h"
#include "lwesp/lwesp.h"
/* Host parameter */
#define CONN_HOST "example.com"
#define CONN_PORT 80
static lwespr_t conn_callback_func(lwesp_evt_t* evt);
/**
* \brief Request data for connection
*/
static const
uint8_t req_data[] = ""
"GET / HTTP/1.1\r\n"
"Host: " CONN_HOST "\r\n"
"Connection: close\r\n"
"\r\n";
/**
* \brief Start a new connection(s) as client
*/
void
client_connect(void) {
lwespr_t res;
/* Start a new connection as client in non-blocking mode */
if ((res = lwesp_conn_start(NULL, LWESP_CONN_TYPE_TCP, "example.com", 80, NULL, conn_callback_func, 0)) == lwespOK) {
printf("Connection to " CONN_HOST " started...\r\n");
} else {
printf("Cannot start connection to " CONN_HOST "!\r\n");
}
/* Start 2 more */
lwesp_conn_start(NULL, LWESP_CONN_TYPE_TCP, CONN_HOST, CONN_PORT, NULL, conn_callback_func, 0);
/*
* An example of connection which should fail in connecting.
* When this is the case, \ref LWESP_EVT_CONN_ERROR event should be triggered
* in callback function processing
*/
lwesp_conn_start(NULL, LWESP_CONN_TYPE_TCP, CONN_HOST, 10, NULL, conn_callback_func, 0);
}
/**
* \brief Event callback function for connection-only
* \param[in] evt: Event information with data
* \return \ref lwespOK on success, member of \ref lwespr_t otherwise
*/
static lwespr_t
conn_callback_func(lwesp_evt_t* evt) {
lwesp_conn_p conn;
lwespr_t res;
uint8_t conn_num;
conn = lwesp_conn_get_from_evt(evt); /* Get connection handle from event */
if (conn == NULL) {
return lwespERR;
}
conn_num = lwesp_conn_getnum(conn); /* Get connection number for identification */
switch (lwesp_evt_get_type(evt)) {
case LWESP_EVT_CONN_ACTIVE: { /* Connection just active */
printf("Connection %d active!\r\n", (int)conn_num);
res = lwesp_conn_send(conn, req_data, sizeof(req_data) - 1, NULL, 0); /* Start sending data in non-blocking mode */
if (res == lwespOK) {
printf("Sending request data to server...\r\n");
} else {
printf("Cannot send request data to server. Closing connection manually...\r\n");
lwesp_conn_close(conn, 0); /* Close the connection */
}
break;
}
case LWESP_EVT_CONN_CLOSE: { /* Connection closed */
if (lwesp_evt_conn_close_is_forced(evt)) {
printf("Connection %d closed by client!\r\n", (int)conn_num);
} else {
printf("Connection %d closed by remote side!\r\n", (int)conn_num);
}
break;
}
case LWESP_EVT_CONN_SEND: { /* Data send event */
lwespr_t res = lwesp_evt_conn_send_get_result(evt);
if (res == lwespOK) {
printf("Data sent successfully on connection %d...waiting to receive data from remote side...\r\n", (int)conn_num);
} else {
printf("Error while sending data on connection %d!\r\n", (int)conn_num);
}
break;
}
case LWESP_EVT_CONN_RECV: { /* Data received from remote side */
lwesp_pbuf_p pbuf = lwesp_evt_conn_recv_get_buff(evt);
lwesp_conn_recved(conn, pbuf); /* Notify stack about received pbuf */
printf("Received %d bytes on connection %d..\r\n", (int)lwesp_pbuf_length(pbuf, 1), (int)conn_num);
break;
}
case LWESP_EVT_CONN_ERROR: { /* Error connecting to server */
const char* host = lwesp_evt_conn_error_get_host(evt);
lwesp_port_t port = lwesp_evt_conn_error_get_port(evt);
printf("Error connecting to %s:%d\r\n", host, (int)port);
break;
}
default:
break;
}
return lwespOK;
}
|
API call event¶
API function call event function is special type of event and is linked to command execution. It is especially useful when dealing with non-blocking commands to understand when specific command execution finished and when next operation could start.
Every API function, which directly operates with AT command on physical device layer,
has optional 2 parameters for API call event:
Callback function, called when command finished
Custom user parameter for callback function
Below is an example code for DNS resolver. It uses custom API callback function with custom argument, used to distinguis domain name (when multiple domains are to be resolved).
Simple example for API call event, using DNS module¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | #include "dns.h"
#include "lwesp/lwesp.h"
/* Host to resolve */
#define DNS_HOST1 "example.com"
#define DNS_HOST2 "example.net"
/**
* \brief Variable to hold result of DNS resolver
*/
static lwesp_ip_t ip;
/**
* \brief Event callback function for API call,
* called when API command finished with execution
*/
static void
dns_resolve_evt(lwespr_t res, void* arg) {
/* Check result of command */
if (res == lwespOK) {
/* DNS resolver has IP address */
printf("DNS record for %s (from API callback): %d.%d.%d.%d\r\n",
(const char*)arg, (int)ip.ip[0], (int)ip.ip[1], (int)ip.ip[2], (int)ip.ip[3]);
}
}
/**
* \brief Start DNS resolver
*/
void
dns_start(void) {
/* Use DNS protocol to get IP address of domain name */
/* Get IP with non-blocking mode */
if (lwesp_dns_gethostbyname(DNS_HOST2, &ip, dns_resolve_evt, DNS_HOST2, 0) == lwespOK) {
printf("Request for DNS record for " DNS_HOST2 " has started\r\n");
} else {
printf("Could not start command for DNS\r\n");
}
/* Get IP with blocking mode */
if (lwesp_dns_gethostbyname(DNS_HOST1, &ip, dns_resolve_evt, DNS_HOST1, 1) == lwespOK) {
printf("DNS record for " DNS_HOST1 " (from lin code): %d.%d.%d.%d\r\n",
(int)ip.ip[0], (int)ip.ip[1], (int)ip.ip[2], (int)ip.ip[3]);
} else {
printf("Could not retrieve IP address for " DNS_HOST1 "\r\n");
}
}
|