// 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 #include #include #include "esp_err.h" #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" #ifdef __cplusplus extern "C" { #endif /** * @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; /** * @brief Keep alive parameters structure */ typedef struct tls_keep_alive_cfg { bool keep_alive_enable; /*!< Enable keep-alive timeout */ int keep_alive_idle; /*!< Keep-alive idle time (second) */ int keep_alive_interval; /*!< Keep-alive interval time (second) */ int keep_alive_count; /*!< Keep-alive packet retry send count */ } tls_keep_alive_cfg_t; /** * @brief ESP-TLS configuration parameters */ typedef struct esp_tls_cfg { 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: "\x02h2" - where the first '2' is the length of the protocol and - the subsequent 'h2' is the protocol name */ const unsigned char *cacert_pem_buf; /*!< Certificate Authority's certificate in a buffer. This buffer should be NULL terminated */ unsigned int cacert_pem_bytes; /*!< Size of Certificate Authority certificate pointed to by cacert_pem_buf */ const unsigned char *clientcert_pem_buf;/*!< Client certificate in a buffer This buffer should be NULL terminated */ unsigned int clientcert_pem_bytes; /*!< Size of client certificate pointed to by clientcert_pem_buf */ const unsigned char *clientkey_pem_buf; /*!< Client key in a buffer This buffer should be NULL terminated */ unsigned int clientkey_pem_bytes; /*!< Size of client key pointed to by clientkey_pem_buf */ 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 */ 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 */ tls_keep_alive_cfg_t *keep_alive_cfg; /*!< Enable TCP keep-alive timeout for SSL connection */ } esp_tls_cfg_t; /** * @brief ESP-TLS Connection Handle */ typedef struct esp_tls { 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 */ int sockfd; /*!< Underlying socket file descriptor. */ ssize_t (*read)(struct esp_tls *tls, char *data, size_t datalen); /*!< Callback function for reading data from TLS/SSL connection. */ 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_t; /** * @brief Create a new blocking TLS/SSL connection * * This function establishes a TLS/SSL connection with the specified host in blocking manner. * * @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); /** * @brief Create a new 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. 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); /** * @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) { return tls->write(tls, (char *)data, datalen); } /** * @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. */ static inline ssize_t esp_tls_conn_read(esp_tls_t *tls, void *data, size_t datalen) { return tls->read(tls, (char *)data, datalen); } /** * @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 */ size_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(); /** * @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(); /** * @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(); #ifdef __cplusplus } #endif #endif /* ! _ESP_TLS_H_ */