OVMS3-idf/components/esp-tls/esp_tls.h

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// Copyright 2017-2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef _ESP_TLS_H_
#define _ESP_TLS_H_
#include <stdbool.h>
#include <sys/socket.h>
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#include <fcntl.h>
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#include "mbedtls/platform.h"
#include "mbedtls/net_sockets.h"
#include "mbedtls/esp_debug.h"
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/error.h"
#include "mbedtls/certs.h"
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#ifdef __cplusplus
extern "C" {
#endif
#define ESP_ERR_ESP_TLS_BASE 0x8000 /*!< Starting number of ESP-TLS error codes */
#define ESP_ERR_ESP_TLS_CANNOT_RESOLVE_HOSTNAME (ESP_ERR_ESP_TLS_BASE + 0x01) /*!< Error if hostname couldn't be resolved upon tls connection */
#define ESP_ERR_ESP_TLS_CANNOT_CREATE_SOCKET (ESP_ERR_ESP_TLS_BASE + 0x02) /*!< Failed to create socket */
#define ESP_ERR_ESP_TLS_UNSUPPORTED_PROTOCOL_FAMILY (ESP_ERR_ESP_TLS_BASE + 0x03) /*!< Unsupported protocol family */
#define ESP_ERR_ESP_TLS_FAILED_CONNECT_TO_HOST (ESP_ERR_ESP_TLS_BASE + 0x04) /*!< Failed to connect to host */
#define ESP_ERR_ESP_TLS_SOCKET_SETOPT_FAILED (ESP_ERR_ESP_TLS_BASE + 0x05) /*!< failed to set socket option */
#define ESP_ERR_MBEDTLS_CERT_PARTLY_OK (ESP_ERR_ESP_TLS_BASE + 0x06) /*!< mbedtls parse certificates was partly successful */
#define ESP_ERR_MBEDTLS_CTR_DRBG_SEED_FAILED (ESP_ERR_ESP_TLS_BASE + 0x07) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_SET_HOSTNAME_FAILED (ESP_ERR_ESP_TLS_BASE + 0x08) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_CONFIG_DEFAULTS_FAILED (ESP_ERR_ESP_TLS_BASE + 0x09) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_CONF_ALPN_PROTOCOLS_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0A) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_X509_CRT_PARSE_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0B) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_CONF_OWN_CERT_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0C) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_SETUP_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0D) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_SSL_WRITE_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0E) /*!< mbedtls api returned error */
#define ESP_ERR_MBEDTLS_PK_PARSE_KEY_FAILED (ESP_ERR_ESP_TLS_BASE + 0x0F) /*!< mbedtls api returned failed */
#define ESP_ERR_MBEDTLS_SSL_HANDSHAKE_FAILED (ESP_ERR_ESP_TLS_BASE + 0x10) /*!< mbedtls api returned failed */
#define ESP_ERR_MBEDTLS_SSL_CONF_PSK_FAILED (ESP_ERR_ESP_TLS_BASE + 0x11) /*!< mbedtls api returned failed */
typedef struct esp_tls_last_error* esp_tls_error_handle_t;
/**
* @brief Error structure containing relevant errors in case tls error occurred
*/
typedef struct esp_tls_last_error {
esp_err_t last_error; /*!< error code (based on ESP_ERR_ESP_TLS_BASE) of the last occurred error */
int mbedtls_error_code; /*!< mbedtls error code from last mbedtls failed api */
int mbedtls_flags; /*!< last certification verification flags */
} esp_tls_last_error_t;
/**
* @brief ESP-TLS Connection State
*/
typedef enum esp_tls_conn_state {
ESP_TLS_INIT = 0,
ESP_TLS_CONNECTING,
ESP_TLS_HANDSHAKE,
ESP_TLS_FAIL,
ESP_TLS_DONE,
} esp_tls_conn_state_t;
typedef enum esp_tls_role {
ESP_TLS_CLIENT = 0,
ESP_TLS_SERVER,
} esp_tls_role_t;
/**
* @brief ESP-TLS preshared key and hint structure
*/
typedef struct psk_key_hint {
const uint8_t* key; /*!< key in PSK authentication mode in binary format */
const size_t key_size; /*!< length of the key */
const char* hint; /*!< hint in PSK authentication mode in string format */
} psk_hint_key_t;
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/**
* @brief ESP-TLS configuration parameters
*
* @note Note about format of certificates:
* - This structure includes certificates of a Certificate Authority, of client or server as well
* as private keys, which may be of PEM or DER format. In case of PEM format, the buffer must be
* NULL terminated (with NULL character included in certificate size).
* - Certificate Authority's certificate may be a chain of certificates in case of PEM format,
* but could be only one certificate in case of DER format
* - Variables names of certificates and private key buffers and sizes are defined as unions providing
* backward compatibility for legacy *_pem_buf and *_pem_bytes names which suggested only PEM format
* was supported. It is encouraged to use generic names such as cacert_buf and cacert_bytes.
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*/
typedef struct esp_tls_cfg {
const char **alpn_protos; /*!< Application protocols required for HTTP2.
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If HTTP2/ALPN support is required, a list
of protocols that should be negotiated.
The format is length followed by protocol
name.
For the most common cases the following is ok:
const char **alpn_protos = { "h2", NULL };
- where 'h2' is the protocol name */
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union {
const unsigned char *cacert_buf; /*!< Certificate Authority's certificate in a buffer.
Format may be PEM or DER, depending on mbedtls-support
This buffer should be NULL terminated in case of PEM */
const unsigned char *cacert_pem_buf; /*!< CA certificate buffer legacy name */
};
union {
unsigned int cacert_bytes; /*!< Size of Certificate Authority certificate
pointed to by cacert_buf
(including NULL-terminator in case of PEM format) */
unsigned int cacert_pem_bytes; /*!< Size of Certificate Authority certificate legacy name */
};
union {
const unsigned char *clientcert_buf; /*!< Client certificate in a buffer
Format may be PEM or DER, depending on mbedtls-support
This buffer should be NULL terminated in case of PEM */
const unsigned char *clientcert_pem_buf; /*!< Client certificate legacy name */
};
union {
unsigned int clientcert_bytes; /*!< Size of client certificate pointed to by
clientcert_pem_buf
(including NULL-terminator in case of PEM format) */
unsigned int clientcert_pem_bytes; /*!< Size of client certificate legacy name */
};
union {
const unsigned char *clientkey_buf; /*!< Client key in a buffer
Format may be PEM or DER, depending on mbedtls-support
This buffer should be NULL terminated in case of PEM */
const unsigned char *clientkey_pem_buf; /*!< Client key legacy name */
};
union {
unsigned int clientkey_bytes; /*!< Size of client key pointed to by
clientkey_pem_buf
(including NULL-terminator in case of PEM format) */
unsigned int clientkey_pem_bytes; /*!< Size of client key legacy name */
};
const unsigned char *clientkey_password;/*!< Client key decryption password string */
unsigned int clientkey_password_len; /*!< String length of the password pointed to by
clientkey_password */
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bool non_block; /*!< Configure non-blocking mode. If set to true the
underneath socket will be configured in non
blocking mode after tls session is established */
int timeout_ms; /*!< Network timeout in milliseconds */
bool use_global_ca_store; /*!< Use a global ca_store for all the connections in which
this bool is set. */
const char *common_name; /*!< If non-NULL, server certificate CN must match this name.
If NULL, server certificate CN must match hostname. */
bool skip_common_name; /*!< Skip any validation of server certificate CN field */
const psk_hint_key_t* psk_hint_key; /*!< Pointer to PSK hint and key. if not NULL (and certificates are NULL)
then PSK authentication is enabled with configured setup.
Important note: the pointer must be valid for connection */
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} esp_tls_cfg_t;
#ifdef CONFIG_ESP_TLS_SERVER
typedef struct esp_tls_cfg_server {
const char **alpn_protos; /*!< Application protocols required for HTTP2.
If HTTP2/ALPN support is required, a list
of protocols that should be negotiated.
The format is length followed by protocol
name.
For the most common cases the following is ok:
const char **alpn_protos = { "h2", NULL };
- where 'h2' is the protocol name */
union {
const unsigned char *cacert_buf; /*!< Client CA certificate in a buffer.
This buffer should be NULL terminated */
const unsigned char *cacert_pem_buf; /*!< Client CA certificate legacy name */
};
union {
unsigned int cacert_bytes; /*!< Size of client CA certificate
pointed to by cacert_pem_buf */
unsigned int cacert_pem_bytes; /*!< Size of client CA certificate legacy name */
};
union {
const unsigned char *servercert_buf; /*!< Server certificate in a buffer
This buffer should be NULL terminated */
const unsigned char *servercert_pem_buf; /*!< Server certificate legacy name */
};
union {
unsigned int servercert_bytes; /*!< Size of server certificate pointed to by
servercert_pem_buf */
unsigned int servercert_pem_bytes; /*!< Size of server certificate legacy name */
};
union {
const unsigned char *serverkey_buf; /*!< Server key in a buffer
This buffer should be NULL terminated */
const unsigned char *serverkey_pem_buf; /*!< Server key legacy name */
};
union {
unsigned int serverkey_bytes; /*!< Size of server key pointed to by
serverkey_pem_buf */
unsigned int serverkey_pem_bytes; /*!< Size of server key legacy name */
};
const unsigned char *serverkey_password; /*!< Server key decryption password string */
unsigned int serverkey_password_len; /*!< String length of the password pointed to by
serverkey_password */
} esp_tls_cfg_server_t;
#endif /* ! CONFIG_ESP_TLS_SERVER */
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/**
* @brief ESP-TLS Connection Handle
*/
typedef struct esp_tls {
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mbedtls_ssl_context ssl; /*!< TLS/SSL context */
mbedtls_entropy_context entropy; /*!< mbedTLS entropy context structure */
mbedtls_ctr_drbg_context ctr_drbg; /*!< mbedTLS ctr drbg context structure.
CTR_DRBG is deterministic random
bit generation based on AES-256 */
mbedtls_ssl_config conf; /*!< TLS/SSL configuration to be shared
between mbedtls_ssl_context
structures */
mbedtls_net_context server_fd; /*!< mbedTLS wrapper type for sockets */
mbedtls_x509_crt cacert; /*!< Container for the X.509 CA certificate */
mbedtls_x509_crt *cacert_ptr; /*!< Pointer to the cacert being used. */
mbedtls_x509_crt clientcert; /*!< Container for the X.509 client certificate */
mbedtls_pk_context clientkey; /*!< Container for the private key of the client
certificate */
#ifdef CONFIG_ESP_TLS_SERVER
mbedtls_x509_crt servercert; /*!< Container for the X.509 server certificate */
mbedtls_pk_context serverkey; /*!< Container for the private key of the server
certificate */
#endif
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int sockfd; /*!< Underlying socket file descriptor. */
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ssize_t (*read)(struct esp_tls *tls, char *data, size_t datalen); /*!< Callback function for reading data from TLS/SSL
connection. */
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ssize_t (*write)(struct esp_tls *tls, const char *data, size_t datalen); /*!< Callback function for writing data to TLS/SSL
connection. */
esp_tls_conn_state_t conn_state; /*!< ESP-TLS Connection state */
fd_set rset; /*!< read file descriptors */
fd_set wset; /*!< write file descriptors */
bool is_tls; /*!< indicates connection type (TLS or NON-TLS) */
esp_tls_role_t role; /*!< esp-tls role
- ESP_TLS_CLIENT
- ESP_TLS_SERVER */
esp_tls_error_handle_t error_handle; /*!< handle to error descriptor */
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} esp_tls_t;
/**
* @brief Create TLS connection
*
* This function allocates and initializes esp-tls structure handle.
*
* @return tls Pointer to esp-tls as esp-tls handle if successfully initialized,
* NULL if allocation error
*/
esp_tls_t *esp_tls_init(void);
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/**
* @brief Create a new blocking TLS/SSL connection
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*
* This function establishes a TLS/SSL connection with the specified host in blocking manner.
*
* Note: This API is present for backward compatibility reasons. Alternative function
* with the same functionality is `esp_tls_conn_new_sync` (and its asynchronous version
* `esp_tls_conn_new_async`)
*
* @param[in] hostname Hostname of the host.
* @param[in] hostlen Length of hostname.
* @param[in] port Port number of the host.
* @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open
* non-TLS connection, keep this NULL. For TLS connection,
* a pass pointer to esp_tls_cfg_t. At a minimum, this
* structure should be zero-initialized.
*
* @return pointer to esp_tls_t, or NULL if connection couldn't be opened.
*/
esp_tls_t *esp_tls_conn_new(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg) __attribute__ ((deprecated));
/**
* @brief Create a new blocking TLS/SSL connection
*
* This function establishes a TLS/SSL connection with the specified host in blocking manner.
*
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* @param[in] hostname Hostname of the host.
* @param[in] hostlen Length of hostname.
* @param[in] port Port number of the host.
* @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open
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* non-TLS connection, keep this NULL. For TLS connection,
* a pass pointer to esp_tls_cfg_t. At a minimum, this
* structure should be zero-initialized.
* @param[in] tls Pointer to esp-tls as esp-tls handle.
*
* @return
* - -1 If connection establishment fails.
* - 1 If connection establishment is successful.
* - 0 Reserved for connection state is in progress.
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*/
int esp_tls_conn_new_sync(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls);
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/**
* @brief Create a new blocking TLS/SSL connection with a given "HTTP" url
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*
* The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url.
*
* @param[in] url url of host.
* @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open
* non-TLS connection, keep this NULL. For TLS connection,
* a pass pointer to 'esp_tls_cfg_t'. At a minimum, this
* structure should be zero-initialized.
* @return pointer to esp_tls_t, or NULL if connection couldn't be opened.
*/
esp_tls_t *esp_tls_conn_http_new(const char *url, const esp_tls_cfg_t *cfg);
/**
* @brief Create a new non-blocking TLS/SSL connection
*
* This function initiates a non-blocking TLS/SSL connection with the specified host, but due to
* its non-blocking nature, it doesn't wait for the connection to get established.
*
* @param[in] hostname Hostname of the host.
* @param[in] hostlen Length of hostname.
* @param[in] port Port number of the host.
* @param[in] cfg TLS configuration as esp_tls_cfg_t. `non_block` member of
* this structure should be set to be true.
* @param[in] tls pointer to esp-tls as esp-tls handle.
*
* @return
* - -1 If connection establishment fails.
* - 0 If connection establishment is in progress.
* - 1 If connection establishment is successful.
*/
int esp_tls_conn_new_async(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls);
/**
* @brief Create a new non-blocking TLS/SSL connection with a given "HTTP" url
*
* The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url.
*
* @param[in] url url of host.
* @param[in] cfg TLS configuration as esp_tls_cfg_t.
* @param[in] tls pointer to esp-tls as esp-tls handle.
*
* @return
* - -1 If connection establishment fails.
* - 0 If connection establishment is in progress.
* - 1 If connection establishment is successful.
*/
int esp_tls_conn_http_new_async(const char *url, const esp_tls_cfg_t *cfg, esp_tls_t *tls);
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/**
* @brief Write from buffer 'data' into specified tls connection.
*
* @param[in] tls pointer to esp-tls as esp-tls handle.
* @param[in] data Buffer from which data will be written.
* @param[in] datalen Length of data buffer.
*
* @return
* - >0 if write operation was successful, the return value is the number
* of bytes actually written to the TLS/SSL connection.
* - 0 if write operation was not successful. The underlying
* connection was closed.
* - <0 if write operation was not successful, because either an
* error occured or an action must be taken by the calling process.
*/
static inline ssize_t esp_tls_conn_write(esp_tls_t *tls, const void *data, size_t datalen)
{
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return tls->write(tls, (char *)data, datalen);
}
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/**
* @brief Read from specified tls connection into the buffer 'data'.
*
* @param[in] tls pointer to esp-tls as esp-tls handle.
* @param[in] data Buffer to hold read data.
* @param[in] datalen Length of data buffer.
*
* @return
* - >0 if read operation was successful, the return value is the number
* of bytes actually read from the TLS/SSL connection.
* - 0 if read operation was not successful. The underlying
* connection was closed.
* - <0 if read operation was not successful, because either an
* error occured or an action must be taken by the calling process.
*/
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static inline ssize_t esp_tls_conn_read(esp_tls_t *tls, void *data, size_t datalen)
{
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return tls->read(tls, (char *)data, datalen);
}
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/**
* @brief Close the TLS/SSL connection and free any allocated resources.
*
* This function should be called to close each tls connection opened with esp_tls_conn_new() or
* esp_tls_conn_http_new() APIs.
*
* @param[in] tls pointer to esp-tls as esp-tls handle.
*/
void esp_tls_conn_delete(esp_tls_t *tls);
/**
* @brief Return the number of application data bytes remaining to be
* read from the current record
*
* This API is a wrapper over mbedtls's mbedtls_ssl_get_bytes_avail() API.
*
* @param[in] tls pointer to esp-tls as esp-tls handle.
*
* @return
* - -1 in case of invalid arg
* - bytes available in the application data
* record read buffer
*/
ssize_t esp_tls_get_bytes_avail(esp_tls_t *tls);
/**
* @brief Create a global CA store, initially empty.
*
* This function should be called if the application wants to use the same CA store for multiple connections.
* This function initialises the global CA store which can be then set by calling esp_tls_set_global_ca_store().
* To be effective, this function must be called before any call to esp_tls_set_global_ca_store().
*
* @return
* - ESP_OK if creating global CA store was successful.
* - ESP_ERR_NO_MEM if an error occured when allocating the mbedTLS resources.
*/
esp_err_t esp_tls_init_global_ca_store(void);
/**
* @brief Set the global CA store with the buffer provided in pem format.
*
* This function should be called if the application wants to set the global CA store for
* multiple connections i.e. to add the certificates in the provided buffer to the certificate chain.
* This function implicitly calls esp_tls_init_global_ca_store() if it has not already been called.
* The application must call this function before calling esp_tls_conn_new().
*
* @param[in] cacert_pem_buf Buffer which has certificates in pem format. This buffer
* is used for creating a global CA store, which can be used
* by other tls connections.
* @param[in] cacert_pem_bytes Length of the buffer.
*
* @return
* - ESP_OK if adding certificates was successful.
* - Other if an error occured or an action must be taken by the calling process.
*/
esp_err_t esp_tls_set_global_ca_store(const unsigned char *cacert_pem_buf, const unsigned int cacert_pem_bytes);
/**
* @brief Get the pointer to the global CA store currently being used.
*
* The application must first call esp_tls_set_global_ca_store(). Then the same
* CA store could be used by the application for APIs other than esp_tls.
*
* @note Modifying the pointer might cause a failure in verifying the certificates.
*
* @return
* - Pointer to the global CA store currently being used if successful.
* - NULL if there is no global CA store set.
*/
mbedtls_x509_crt *esp_tls_get_global_ca_store(void);
/**
* @brief Free the global CA store currently being used.
*
* The memory being used by the global CA store to store all the parsed certificates is
* freed up. The application can call this API if it no longer needs the global CA store.
*/
void esp_tls_free_global_ca_store(void);
/**
* @brief Returns last error in esp_tls with detailed mbedtls related error codes.
* The error information is cleared internally upon return
*
* @param[in] h esp-tls error handle.
* @param[out] mbedtls_code last error code returned from mbedtls api (set to zero if none)
* This pointer could be NULL if caller does not care about mbedtls_code
* @param[out] mbedtls_flags last certification verification flags (set to zero if none)
* This pointer could be NULL if caller does not care about mbedtls_flags
*
* @return
* - ESP_ERR_INVALID_STATE if invalid parameters
* - ESP_OK (0) if no error occurred
* - specific error code (based on ESP_ERR_ESP_TLS_BASE) otherwise
*/
esp_err_t esp_tls_get_and_clear_last_error(esp_tls_error_handle_t h, int *mbedtls_code, int *mbedtls_flags);
#ifdef CONFIG_ESP_TLS_SERVER
/**
* @brief Create TLS/SSL server session
*
* This function creates a TLS/SSL server context for already accepted client connection
* and performs TLS/SSL handshake with the client
*
* @param[in] cfg Pointer to esp_tls_cfg_server_t
* @param[in] sockfd FD of accepted connection
* @param[out] tls Pointer to allocated esp_tls_t
*
* @return
* - 0 if successful
* - <0 in case of error
*
*/
int esp_tls_server_session_create(esp_tls_cfg_server_t *cfg, int sockfd, esp_tls_t *tls);
/**
* @brief Close the server side TLS/SSL connection and free any allocated resources.
*
* This function should be called to close each tls connection opened with esp_tls_server_session_create()
*
* @param[in] tls pointer to esp_tls_t
*/
void esp_tls_server_session_delete(esp_tls_t *tls);
#endif /* ! CONFIG_ESP_TLS_SERVER */
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#ifdef __cplusplus
}
#endif
#endif /* ! _ESP_TLS_H_ */