# 协议通信

[English]

## 概述

协议通信 (protocomm) 组件用于管理安全会话并为多种传输提供框架。应用程序还可以直接使用 protocomm 层来增加特定扩展，用于配网或非配网使用场景。

以下功能可用于配网：

> - 应用程序层面的通信安全

>   > - `protocomm_security0` （无安全功能）

>   > - `protocomm_security1` （Curve25519 密钥交换 + AES-CTR 加密/解密）

>   > - `protocomm_security2` （基于 SRP6a 的密钥交换 + AES-GCM 加密/解密）

> - 所有权验证 (Proof-of-possession)（仅 `protocomm_security1` 支持该功能）

> - 盐值和验证器 (Salt and Verifier)（仅 `protocomm_security2` 支持该功能）

在 protocomm 内部，protobuf（协议缓冲区）用于建立安全会话。用户可以自行选择（即使在不使用 Protobuf 的情况下）实现安全性，也可以在没有任何安全层的情况下使用协议。

Protocomm 为以下各种传输提供框架：

- 低功耗蓝牙

- Wi-Fi (SoftAP + HTTPD)

- 控制台：使用该传输方案时，设备端会自动调用处理程序。相关代码片段，请参见下文传输示例。

请注意，对于 `protocomm_security1` 和 `protocomm_security2`，客户端仍需要执行双向握手来建立会话。

关于安全握手逻辑的详情，请参阅 统一配网。

## 启用 protocomm 安全版本

关于启用/禁用相应的安全版本，请参阅 protocomm 组件的项目配置菜单。相应配置选项如下：

> - 支持 `protocomm_security0`，该版本无安全功能：CONFIG_ESP_PROTOCOMM_SUPPORT_SECURITY_VERSION_0，该选项默认启用。

> - 支持 `protocomm_security1`，使用 Curve25519 密钥交换和 AES-CTR 加密/解密：CONFIG_ESP_PROTOCOMM_SUPPORT_SECURITY_VERSION_1，该选项默认启用。

> - 支持 `protocomm_security2`，使用基于 SRP6a 的密钥交换和 AES-GCM 加密/解密：CONFIG_ESP_PROTOCOMM_SUPPORT_SECURITY_VERSION_2。

备注

启用多个安全版本后可以动态控制安全版本，但也会增加固件大小。

## 使用 Security 2 的 SoftAP + HTTP 传输方案示例

示例用法请参阅 wifi_provisioning/src/scheme_softap.c。

    /* 此为将通过 protocomm 注册的端点处理程序，会直接回显接收到的数据 */
    esp_err_t echo_req_handler (uint32_t session_id,
                                const uint8_t *inbuf, ssize_t inlen,
                                uint8_t **outbuf, ssize_t *outlen,
                                void *priv_data)
    {
        /* Session ID 可以用于持久化 */
        printf("Session ID : %d", session_id);

        /* 回显接收到的数据 */
        *outlen = inlen;            /* 输出更新后的数据长度 */
        *outbuf = malloc(inlen);    /* 将在外部释放 */
        memcpy(*outbuf, inbuf, inlen);

        /* 端点创建时传递的私有数据 */
        uint32_t *priv = (uint32_t *) priv_data;
        if (priv) {
            printf("Private data : %d", *priv);
        }

        return ESP_OK;
    }

    static const char sec2_salt[] = {0xf7, 0x5f, 0xe2, 0xbe, 0xba, 0x7c, 0x81, 0xcd};
    static const char sec2_verifier[] = {0xbf, 0x86, 0xce, 0x63, 0x8a, 0xbb, 0x7e, 0x2f, 0x38, 0xa8, 0x19, 0x1b, 0x35,
        0xc9, 0xe3, 0xbe, 0xc3, 0x2b, 0x45, 0xee, 0x10, 0x74, 0x22, 0x1a, 0x95, 0xbe, 0x62, 0xf7, 0x0c, 0x65, 0x83, 0x50,
        0x08, 0xef, 0xaf, 0xa5, 0x94, 0x4b, 0xcb, 0xe1, 0xce, 0x59, 0x2a, 0xe8, 0x7b, 0x27, 0xc8, 0x72, 0x26, 0x71, 0xde,
        0xb2, 0xf2, 0x80, 0x02, 0xdd, 0x11, 0xf0, 0x38, 0x0e, 0x95, 0x25, 0x00, 0xcf, 0xb3, 0x3f, 0xf0, 0x73, 0x2a, 0x25,
        0x03, 0xe8, 0x51, 0x72, 0xef, 0x6d, 0x3e, 0x14, 0xb9, 0x2e, 0x9f, 0x2a, 0x90, 0x9e, 0x26, 0xb6, 0x3e, 0xc7, 0xe4,
        0x9f, 0xe3, 0x20, 0xce, 0x28, 0x7c, 0xbf, 0x89, 0x50, 0xc9, 0xb6, 0xec, 0xdd, 0x81, 0x18, 0xf1, 0x1a, 0xd9, 0x7a,
        0x21, 0x99, 0xf1, 0xee, 0x71, 0x2f, 0xcc, 0x93, 0x16, 0x34, 0x0c, 0x79, 0x46, 0x23, 0xe4, 0x32, 0xec, 0x2d, 0x9e,
        0x18, 0xa6, 0xb9, 0xbb, 0x0a, 0xcf, 0xc4, 0xa8, 0x32, 0xc0, 0x1c, 0x32, 0xa3, 0x97, 0x66, 0xf8, 0x30, 0xb2, 0xda,
        0xf9, 0x8d, 0xc3, 0x72, 0x72, 0x5f, 0xe5, 0xee, 0xc3, 0x5c, 0x24, 0xc8, 0xdd, 0x54, 0x49, 0xfc, 0x12, 0x91, 0x81,
        0x9c, 0xc3, 0xac, 0x64, 0x5e, 0xd6, 0x41, 0x88, 0x2f, 0x23, 0x66, 0xc8, 0xac, 0xb0, 0x35, 0x0b, 0xf6, 0x9c, 0x88,
        0x6f, 0xac, 0xe1, 0xf4, 0xca, 0xc9, 0x07, 0x04, 0x11, 0xda, 0x90, 0x42, 0xa9, 0xf1, 0x97, 0x3d, 0x94, 0x65, 0xe4,
        0xfb, 0x52, 0x22, 0x3b, 0x7a, 0x7b, 0x9e, 0xe9, 0xee, 0x1c, 0x44, 0xd0, 0x73, 0x72, 0x2a, 0xca, 0x85, 0x19, 0x4a,
        0x60, 0xce, 0x0a, 0xc8, 0x7d, 0x57, 0xa4, 0xf8, 0x77, 0x22, 0xc1, 0xa5, 0xfa, 0xfb, 0x7b, 0x91, 0x3b, 0xfe, 0x87,
        0x5f, 0xfe, 0x05, 0xd2, 0xd6, 0xd3, 0x74, 0xe5, 0x2e, 0x68, 0x79, 0x34, 0x70, 0x40, 0x12, 0xa8, 0xe1, 0xb4, 0x6c,
        0xaa, 0x46, 0x73, 0xcd, 0x8d, 0x17, 0x72, 0x67, 0x32, 0x42, 0xdc, 0x10, 0xd3, 0x71, 0x7e, 0x8b, 0x00, 0x46, 0x9b,
        0x0a, 0xe9, 0xb4, 0x0f, 0xeb, 0x70, 0x52, 0xdd, 0x0a, 0x1c, 0x7e, 0x2e, 0xb0, 0x61, 0xa6, 0xe1, 0xa3, 0x34, 0x4b,
        0x2a, 0x3c, 0xc4, 0x5d, 0x42, 0x05, 0x58, 0x25, 0xd3, 0xca, 0x96, 0x5c, 0xb9, 0x52, 0xf9, 0xe9, 0x80, 0x75, 0x3d,
        0xc8, 0x9f, 0xc7, 0xb2, 0xaa, 0x95, 0x2e, 0x76, 0xb3, 0xe1, 0x48, 0xc1, 0x0a, 0xa1, 0x0a, 0xe8, 0xaf, 0x41, 0x28,
        0xd2, 0x16, 0xe1, 0xa6, 0xd0, 0x73, 0x51, 0x73, 0x79, 0x98, 0xd9, 0xb9, 0x00, 0x50, 0xa2, 0x4d, 0x99, 0x18, 0x90,
        0x70, 0x27, 0xe7, 0x8d, 0x56, 0x45, 0x34, 0x1f, 0xb9, 0x30, 0xda, 0xec, 0x4a, 0x08, 0x27, 0x9f, 0xfa, 0x59, 0x2e,
        0x36, 0x77, 0x00, 0xe2, 0xb6, 0xeb, 0xd1, 0x56, 0x50, 0x8e};

    /* 通过 HTTP 启动 protocomm 实例的示例函数 */
    protocomm_t *start_pc()
    {
        protocomm_t *pc = protocomm_new();

        /* 配置 protocomm_httpd_start() */
        protocomm_httpd_config_t pc_config = {
            .data = {
            .config = PROTOCOMM_HTTPD_DEFAULT_CONFIG()
            }
        };

        /* 启动基于 HTTP 的 protocomm 服务器 */
        protocomm_httpd_start(pc, &pc_config);

        /* 从盐值和验证器创建 security2 参数对象。该对象必须在 protocomm 端点作用域内有效，且无需为静态对象，即可以在删除端点时动态分配和释放。*/
        const static protocomm_security2_params_t sec2_params = {
            .salt = (const uint8_t *) salt,
            .salt_len = sizeof(salt),
            .verifier = (const uint8_t *) verifier,
            .verifier_len = sizeof(verifier),
        };

        /* 在应用程序层面为通信设置安全方案。与请求处理程序类似，设置安全方案会创建一个端点，并注册 protocomm_security1 提供的处理程序。也可以使用 protocomm_security0 进行类似操作。单个 protocomm 实例中一次只能设置一种类型的安全方案。*/
        protocomm_set_security(pc, "security_endpoint", &protocomm_security2, &sec2_params);

        /* 传递给端点的私有数据必须在 protocomm 端点作用域内有效。该数据无需为静态数据，即可以在删除端点时动态分配和释放。*/
        static uint32_t priv_data = 1234;

        /* 为 protocomm 实例添加一个新端点，该端点由唯一名称标识，再注册一个处理函数，在执行函数时传递私有数据。只要端点由唯一名称标识，即可添加多个端点。*/
        protocomm_add_endpoint(pc, "echo_req_endpoint",
                               echo_req_handler, (void *) &priv_data);
        return pc;
    }

    /* 停止 protocomm 实例的示例函数 */
    void stop_pc(protocomm_t *pc)
    {
        /* 移除由其唯一名称标识的端点 */
        protocomm_remove_endpoint(pc, "echo_req_endpoint");

        /* 移除由其名称标识的安全端点 */
        protocomm_unset_security(pc, "security_endpoint");

        /* 停止 HTTP 服务器 */
        protocomm_httpd_stop(pc);

        /* 删除（即释放）protocomm 实例 */
        protocomm_delete(pc);
    }

## 使用 Security 1 的 SoftAP + HTTP 传输方案示例

示例用法请参阅 wifi_provisioning/src/scheme_softap.c。

    /* 此为将通过 protocomm 注册的端点处理程序，会直接回显接收到的数据 */
    esp_err_t echo_req_handler (uint32_t session_id,
                                const uint8_t *inbuf, ssize_t inlen,
                                uint8_t **outbuf, ssize_t *outlen,
                                void *priv_data)
    {
        /* Session ID 可以用于持久化 */
        printf("Session ID : %d", session_id);

        /* 回显接收到的数据 */
        *outlen = inlen;            /* 输出更新后的数据长度 */
        *outbuf = malloc(inlen);    /* 将在外部释放 */
        memcpy(*outbuf, inbuf, inlen);

        /* 端点创建时传递的私有数据 */
        uint32_t *priv = (uint32_t *) priv_data;
        if (priv) {
            printf("Private data : %d", *priv);
        }

        return ESP_OK;
    }

    /* 通过 HTTP 启动 protocomm 实例的示例函数 */
    protocomm_t *start_pc(const char *pop_string)
    {
        protocomm_t *pc = protocomm_new();

        /* 配置 protocomm_httpd_start() */
        protocomm_httpd_config_t pc_config = {
            .data = {
            .config = PROTOCOMM_HTTPD_DEFAULT_CONFIG()
            }
        };

        /* 启动基于 HTTP 的 protocomm 服务器 */
        protocomm_httpd_start(pc, &pc_config);

        /* 从 pop_string 创建 security1 参数对象。该对象必须在 protocomm 端点作用域内有效，且无需为静态对象，即可以在删除端点时动态分配和释放。*/
        const static protocomm_security1_params_t sec1_params = {
            .data = (const uint8_t *) strdup(pop_string),
            .len = strlen(pop_string)
        };

        /* 在应用程序层面为通信设置安全方案。与请求处理程序类似，设置安全方案会创建一个端点，并注册 protocomm_security1 提供的处理程序。也可以使用 protocomm_security0 进行类似操作。单个 protocomm 实例中一次只能设置一种类型的安全方案*/
        protocomm_set_security(pc, "security_endpoint", &protocomm_security1, &sec1_params);

        /* 传递给端点的私有数据必须在 protocomm 端点作用域内有效。该数据无需为静态数据，即可以在删除端点时动态分配和释放。*/
        static uint32_t priv_data = 1234;

        /* 为 protocomm 实例添加一个新端点，该端点由唯一名称标识，再注册一个处理函数，在执行函数时传递私有数据。只要端点由唯一名称标识，即可添加多个端点。*/
        protocomm_add_endpoint(pc, "echo_req_endpoint",
                               echo_req_handler, (void *) &priv_data);
        return pc;
    }

    /* 停止 protocomm 实例的示例函数 */
    void stop_pc(protocomm_t *pc)
    {
        /* 移除由其唯一名称标识的端点 */
        protocomm_remove_endpoint(pc, "echo_req_endpoint");

        /* 移除由其名称标识的安全端点 */
        protocomm_unset_security(pc, "security_endpoint");

        /* 停止 HTTP 服务器 */
        protocomm_httpd_stop(pc);

        /* 删除（即释放）protocomm 实例 */
        protocomm_delete(pc);
    }

## 使用 Security 0 的低功耗蓝牙传输方案示例

示例用法请参阅 wifi_provisioning/src/scheme_ble.c。

    /* 通过低功耗蓝牙启动安全 protocomm 实例的示例函数 */
    protocomm_t *start_pc()
    {
        protocomm_t *pc = protocomm_new();

        /* 端点 UUID */
        protocomm_ble_name_uuid_t nu_lookup_table[] = {
            {"security_endpoint", 0xFF51},
            {"echo_req_endpoint", 0xFF52}
        };

        /* 配置 protocomm_ble_start() */
        protocomm_ble_config_t config = {
            .service_uuid = {
                /* 最低有效位 <---------------------------------------
                * ---------------------------------------> 最高有效位 */
                0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80,
                0x00, 0x10, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00,
            },
            .nu_lookup_count = sizeof(nu_lookup_table)/sizeof(nu_lookup_table[0]),
            .nu_lookup = nu_lookup_table
        };

        /* 启动基于低功耗蓝牙的 protocomm 层 */
        protocomm_ble_start(pc, &config);

        /* protocomm_security0 方案不使用所有权证明，因此可以将其保持为 NULL */
        protocomm_set_security(pc, "security_endpoint", &protocomm_security0, NULL);
        protocomm_add_endpoint(pc, "echo_req_endpoint", echo_req_handler, NULL);
        return pc;
    }

    /* 停止 protocomm 实例的示例函数 */
    void stop_pc(protocomm_t *pc)
    {
        protocomm_remove_endpoint(pc, "echo_req_endpoint");
        protocomm_unset_security(pc, "security_endpoint");

        /* 停止低功耗蓝牙 protocomm 服务 */
        protocomm_ble_stop(pc);

        protocomm_delete(pc);
    }

## API 参考

### Header File

- components/protocomm/include/common/protocomm.h

- This header file can be included with:

  >     #include "protocomm.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Functions

protocomm_t *protocomm_new(void)

  Create a new protocomm instance.

  This API will return a new dynamically allocated protocomm instance with all elements of the protocomm_t structure initialized to NULL.

  返回:

    - protocomm_t* : On success

    - NULL : No memory for allocating new instance

void protocomm_delete(protocomm_t *pc)

  Delete a protocomm instance.

  This API will deallocate a protocomm instance that was created using `protocomm_new()`.

  参数:

    pc -- [in] Pointer to the protocomm instance to be deleted

esp_err_t protocomm_add_endpoint(protocomm_t *pc, const char *ep_name, protocomm_req_handler_t h, void *priv_data)

  Add endpoint request handler for a protocomm instance.

  This API will bind an endpoint handler function to the specified endpoint name, along with any private data that needs to be pass to the handler at the time of call.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  - This function internally calls the registered `add_endpoint()` function of the selected transport which is a member of the protocomm_t instance structure.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

    - h -- [in] Endpoint handler function

    - priv_data -- [in] Pointer to private data to be passed as a parameter to the handler function on call. Pass NULL if not needed.

  返回:

    - ESP_OK : Success

    - ESP_FAIL : Error adding endpoint / Endpoint with this name already exists

    - ESP_ERR_NO_MEM : Error allocating endpoint resource

    - ESP_ERR_INVALID_ARG : Null instance/name/handler arguments

esp_err_t protocomm_remove_endpoint(protocomm_t *pc, const char *ep_name)

  Remove endpoint request handler for a protocomm instance.

  This API will remove a registered endpoint handler identified by an endpoint name.

  备注

  - This function internally calls the registered `remove_endpoint()` function which is a member of the protocomm_t instance structure.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

  返回:

    - ESP_OK : Success

    - ESP_ERR_NOT_FOUND : Endpoint with specified name doesn't exist

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_open_session(protocomm_t *pc, uint32_t session_id)

  Allocates internal resources for new transport session.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - session_id -- [in] Unique ID for a communication session

  返回:

    - ESP_OK : Request handled successfully

    - ESP_ERR_NO_MEM : Error allocating internal resource

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_close_session(protocomm_t *pc, uint32_t session_id)

  Frees internal resources used by a transport session.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - session_id -- [in] Unique ID for a communication session

  返回:

    - ESP_OK : Request handled successfully

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_req_handle(protocomm_t *pc, const char *ep_name, uint32_t session_id, const uint8_t *inbuf, ssize_t inlen, uint8_t **outbuf, ssize_t *outlen)

  Calls the registered handler of an endpoint session for processing incoming data and generating the response.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  - Resulting output buffer must be deallocated by the caller.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

    - session_id -- [in] Unique ID for a communication session

    - inbuf -- [in] Input buffer contains input request data which is to be processed by the registered handler

    - inlen -- [in] Length of the input buffer

    - outbuf -- [out] Pointer to internally allocated output buffer, where the resulting response data output from the registered handler is to be stored

    - outlen -- [out] Buffer length of the allocated output buffer

  返回:

    - ESP_OK : Request handled successfully

    - ESP_FAIL : Internal error in execution of registered handler

    - ESP_ERR_NO_MEM : Error allocating internal resource

    - ESP_ERR_NOT_FOUND : Endpoint with specified name doesn't exist

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_set_security(protocomm_t *pc, const char *ep_name, const protocomm_security_t *sec, const void *sec_params)

  Add endpoint security for a protocomm instance.

  This API will bind a security session establisher to the specified endpoint name, along with any proof of possession that may be required for authenticating a session client.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  - The choice of security can be any `protocomm_security_t` instance. Choices `protocomm_security0` and `protocomm_security1` and `protocomm_security2` are readily available.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

    - sec -- [in] Pointer to endpoint security instance

    - sec_params -- [in] Pointer to security params (NULL if not needed) The pointer should contain the security params struct of appropriate security version. For protocomm security version 1 and 2 sec_params should contain pointer to struct of type protocomm_security1_params_t and protocmm_security2_params_t respectively. The contents of this pointer must be valid till the security session has been running and is not closed.

  返回:

    - ESP_OK : Success

    - ESP_FAIL : Error adding endpoint / Endpoint with this name already exists

    - ESP_ERR_INVALID_STATE : Security endpoint already set

    - ESP_ERR_NO_MEM : Error allocating endpoint resource

    - ESP_ERR_INVALID_ARG : Null instance/name/handler arguments

esp_err_t protocomm_unset_security(protocomm_t *pc, const char *ep_name)

  Remove endpoint security for a protocomm instance.

  This API will remove a registered security endpoint identified by an endpoint name.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

  返回:

    - ESP_OK : Success

    - ESP_ERR_NOT_FOUND : Endpoint with specified name doesn't exist

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_set_version(protocomm_t *pc, const char *ep_name, const char *version)

  Set endpoint for version verification.

  This API can be used for setting an application specific protocol version which can be verified by clients through the endpoint.

  备注

  - An endpoint must be bound to a valid protocomm instance, created using `protocomm_new()`.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

    - version -- [in] Version identifier(name) string

  返回:

    - ESP_OK : Success

    - ESP_FAIL : Error adding endpoint / Endpoint with this name already exists

    - ESP_ERR_INVALID_STATE : Version endpoint already set

    - ESP_ERR_NO_MEM : Error allocating endpoint resource

    - ESP_ERR_INVALID_ARG : Null instance/name/handler arguments

esp_err_t protocomm_unset_version(protocomm_t *pc, const char *ep_name)

  Remove version verification endpoint from a protocomm instance.

  This API will remove a registered version endpoint identified by an endpoint name.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - ep_name -- [in] Endpoint identifier(name) string

  返回:

    - ESP_OK : Success

    - ESP_ERR_NOT_FOUND : Endpoint with specified name doesn't exist

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

esp_err_t protocomm_get_sec_version(protocomm_t *pc, int *sec_ver, uint8_t *sec_patch_ver)

  Get the security version of the protocomm instance.

  This API will return the security version of the protocomm instance.

  参数:

    - pc -- [in] Pointer to the protocomm instance

    - sec_ver -- [out] Pointer to the security version

    - sec_patch_ver -- [out] Pointer to the security patch version

  返回:

    - ESP_OK : Success

    - ESP_ERR_INVALID_ARG : Null instance/name arguments

### Type Definitions

typedef esp_err_t (*protocomm_req_handler_t)(uint32_t session_id, const uint8_t *inbuf, ssize_t inlen, uint8_t **outbuf, ssize_t *outlen, void *priv_data)

  Function prototype for protocomm endpoint handler.

typedef struct protocomm protocomm_t

  This structure corresponds to a unique instance of protocomm returned when the API `protocomm_new()` is called. The remaining Protocomm APIs require this object as the first parameter.

  备注

  Structure of the protocomm object is kept private

### Header File

- components/protocomm/include/security/protocomm_security.h

- This header file can be included with:

  >     #include "protocomm_security.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Structures

struct protocomm_security1_params

  Protocomm Security 1 parameters: Proof Of Possession.

  Public Members

  const uint8_t *data

    Pointer to buffer containing the proof of possession data

  uint16_t len

    Length (in bytes) of the proof of possession data

struct protocomm_security2_params

  Protocomm Security 2 parameters: Salt and Verifier.

  Public Members

  const char *salt

    Pointer to the buffer containing the salt

  uint16_t salt_len

    Length (in bytes) of the salt

  const char *verifier

    Pointer to the buffer containing the verifier

  uint16_t verifier_len

    Length (in bytes) of the verifier

struct protocomm_security

  Protocomm security object structure.

  The member functions are used for implementing secure protocomm sessions.

  备注

  This structure should not have any dynamic members to allow re-entrancy

  Public Members

  int ver

    Unique version number of security implementation

  uint8_t patch_ver

    Patch version number of security implementation

  esp_err_t (*init)(protocomm_security_handle_t *handle)

    Function for initializing/allocating security infrastructure

  esp_err_t (*cleanup)(protocomm_security_handle_t handle)

    Function for deallocating security infrastructure

  esp_err_t (*new_transport_session)(protocomm_security_handle_t handle, uint32_t session_id)

    Starts new secure transport session with specified ID

  esp_err_t (*close_transport_session)(protocomm_security_handle_t handle, uint32_t session_id)

    Closes a secure transport session with specified ID

  esp_err_t (*security_req_handler)(protocomm_security_handle_t handle, const void *sec_params, uint32_t session_id, const uint8_t *inbuf, ssize_t inlen, uint8_t **outbuf, ssize_t *outlen, void *priv_data)

    Handler function for authenticating connection request and establishing secure session

  esp_err_t (*encrypt)(protocomm_security_handle_t handle, uint32_t session_id, const uint8_t *inbuf, ssize_t inlen, uint8_t **outbuf, ssize_t *outlen)

    Function which implements the encryption algorithm

  esp_err_t (*decrypt)(protocomm_security_handle_t handle, uint32_t session_id, const uint8_t *inbuf, ssize_t inlen, uint8_t **outbuf, ssize_t *outlen)

    Function which implements the decryption algorithm

### Type Definitions

typedef struct protocomm_security1_params protocomm_security1_params_t

  Protocomm Security 1 parameters: Proof Of Possession.

typedef protocomm_security1_params_t protocomm_security_pop_t

typedef struct protocomm_security2_params protocomm_security2_params_t

  Protocomm Security 2 parameters: Salt and Verifier.

typedef void *protocomm_security_handle_t

typedef struct protocomm_security protocomm_security_t

  Protocomm security object structure.

  The member functions are used for implementing secure protocomm sessions.

  备注

  This structure should not have any dynamic members to allow re-entrancy

### Enumerations

enum protocomm_security_session_event_t

  Events generated by the protocomm security layer.

  These events are generated while establishing secured session.

  Values:

  enumerator PROTOCOMM_SECURITY_SESSION_SETUP_OK

    Secured session established successfully

  enumerator PROTOCOMM_SECURITY_SESSION_INVALID_SECURITY_PARAMS

    Received invalid (NULL) security parameters (username / client public-key)

  enumerator PROTOCOMM_SECURITY_SESSION_CREDENTIALS_MISMATCH

    Received incorrect credentials (username / PoP)

### Header File

- components/protocomm/include/security/protocomm_security0.h

- This header file can be included with:

  >     #include "protocomm_security0.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Header File

- components/protocomm/include/security/protocomm_security1.h

- This header file can be included with:

  >     #include "protocomm_security1.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Header File

- components/protocomm/include/security/protocomm_security2.h

- This header file can be included with:

  >     #include "protocomm_security2.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Header File

- components/protocomm/include/crypto/srp6a/esp_srp.h

- This header file can be included with:

  >     #include "esp_srp.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Functions

esp_srp_handle_t *esp_srp_init(esp_ng_type_t ng)

  Initialize srp context for given NG type.

  备注

  the handle gets freed with `esp_srp_free`

  参数:

    ng -- NG type given by `esp_ng_type_t`

  返回:

    esp_srp_handle_t* srp handle

void esp_srp_free(esp_srp_handle_t *hd)

  free esp_srp_context

  参数:

    hd -- handle to be free

esp_err_t esp_srp_srv_pubkey(esp_srp_handle_t *hd, const char *username, int username_len, const char *pass, int pass_len, int salt_len, char **bytes_B, int *len_B, char **bytes_salt)

  Returns B (pub key) and salt. [Step2.b].

  备注

  *bytes_B MUST NOT BE FREED BY THE CALLER

  备注

  *bytes_salt MUST NOT BE FREE BY THE CALLER

  参数:

    - hd -- esp_srp handle

    - username -- Username not expected NULL terminated

    - username_len -- Username length

    - pass -- Password not expected to be NULL terminated

    - pass_len -- Password length

    - salt_len -- Salt length

    - bytes_B -- Public Key returned

    - len_B -- Length of the public key

    - bytes_salt -- Salt bytes generated

  返回:

    esp_err_t ESP_OK on success, appropriate error otherwise

esp_err_t esp_srp_gen_salt_verifier(const char *username, int username_len, const char *pass, int pass_len, char **bytes_salt, int salt_len, char **verifier, int *verifier_len)

  Generate salt-verifier pair, given username, password and salt length.

  备注

  if API has returned ESP_OK, salt and verifier generated need to be freed by caller

  备注

  Usually, username and password are not saved on the device. Rather salt and verifier are generated outside the device and are embedded. this convenience API can be used to generate salt and verifier on the fly for development use case. OR for devices which intentionally want to generate different password each time and can send it to the client securely. e.g., a device has a display and it shows the pin

  参数:

    - username -- [in] username

    - username_len -- [in] length of the username

    - pass -- [in] password

    - pass_len -- [in] length of the password

    - bytes_salt -- [out] generated salt on successful generation, or NULL

    - salt_len -- [in] salt length

    - verifier -- [out] generated verifier on successful generation, or NULL

    - verifier_len -- [out] length of the generated verifier

  返回:

    esp_err_t ESP_OK on success, appropriate error otherwise

esp_err_t esp_srp_set_salt_verifier(esp_srp_handle_t *hd, const char *salt, int salt_len, const char *verifier, int verifier_len)

  Set the Salt and Verifier pre-generated for a given password. This should be used only if the actual password is not available. The public key can then be generated using esp_srp_srv_pubkey_from_salt_verifier() and not esp_srp_srv_pubkey()

  参数:

    - hd -- esp_srp_handle

    - salt -- pre-generated salt bytes

    - salt_len -- length of the salt bytes

    - verifier -- pre-generated verifier

    - verifier_len -- length of the verifier bytes

  返回:

    esp_err_t ESP_OK on success, appropriate error otherwise

esp_err_t esp_srp_srv_pubkey_from_salt_verifier(esp_srp_handle_t *hd, char **bytes_B, int *len_B)

  Returns B (pub key)[Step2.b] when the salt and verifier are set using esp_srp_set_salt_verifier()

  备注

  *bytes_B MUST NOT BE FREED BY THE CALLER

  参数:

    - hd -- esp_srp handle

    - bytes_B -- Key returned to the called

    - len_B -- Length of the key returned

  返回:

    esp_err_t ESP_OK on success, appropriate error otherwise

esp_err_t esp_srp_get_session_key(esp_srp_handle_t *hd, char *bytes_A, int len_A, char **bytes_key, uint16_t *len_key)

  Get session key in `*bytes_key` given by len in `*len_key`. [Step2.c].

  This calculated session key is used for further communication given the proofs are exchanged/authenticated with `esp_srp_exchange_proofs`

  备注

  *bytes_key MUST NOT BE FREED BY THE CALLER

  参数:

    - hd -- esp_srp handle

    - bytes_A -- Private Key

    - len_A -- Private Key length

    - bytes_key -- Key returned to the caller

    - len_key -- length of the key in *bytes_key

  返回:

    esp_err_t ESP_OK on success, appropriate error otherwise

esp_err_t esp_srp_exchange_proofs(esp_srp_handle_t *hd, char *username, uint16_t username_len, char *bytes_user_proof, char *bytes_host_proof)

  Complete the authentication. If this step fails, the session_key exchanged should not be used.

  This is the final authentication step in SRP algorithm [Step4.1, Step4.b, Step4.c]

  参数:

    - hd -- esp_srp handle

    - username -- Username not expected NULL terminated

    - username_len -- Username length

    - bytes_user_proof -- param in

    - bytes_host_proof -- parameter out (should be SHA512_DIGEST_LENGTH) bytes in size

  返回:

    esp_err_t ESP_OK if user's proof is ok and subsequently bytes_host_proof is populated with our own proof.

### Type Definitions

typedef struct esp_srp_handle esp_srp_handle_t

  esp_srp handle as the result of `esp_srp_init`

  The handle is returned by `esp_srp_init` on successful init. It is then passed for subsequent API calls as an argument. `esp_srp_free` can be used to clean up the handle. After `esp_srp_free` the handle becomes invalid.

### Enumerations

enum esp_ng_type_t

  Large prime+generator to be used for the algorithm.

  Values:

  enumerator ESP_NG_3072

### Header File

- components/protocomm/include/transports/protocomm_httpd.h

- This header file can be included with:

  >     #include "protocomm_httpd.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Functions

esp_err_t protocomm_httpd_start(protocomm_t *pc, const protocomm_httpd_config_t *config)

  Start HTTPD protocomm transport.

  This API internally creates a framework to allow endpoint registration and security configuration for the protocomm.

  备注

  This is a singleton. ie. Protocomm can have multiple instances, but only one instance can be bound to an HTTP transport layer.

  参数:

    - pc -- [in] Protocomm instance pointer obtained from protocomm_new()

    - config -- [in] Pointer to config structure for initializing HTTP server

  返回:

    - ESP_OK : Success

    - ESP_ERR_INVALID_ARG : Null arguments

    - ESP_ERR_NOT_SUPPORTED : Transport layer bound to another protocomm instance

    - ESP_ERR_INVALID_STATE : Transport layer already bound to this protocomm instance

    - ESP_ERR_NO_MEM : Memory allocation for server resource failed

    - ESP_ERR_HTTPD_* : HTTP server error on start

esp_err_t protocomm_httpd_stop(protocomm_t *pc)

  Stop HTTPD protocomm transport.

  This API cleans up the HTTPD transport protocomm and frees all the handlers registered with the protocomm.

  参数:

    pc -- [in] Same protocomm instance that was passed to protocomm_httpd_start()

  返回:

    - ESP_OK : Success

    - ESP_ERR_INVALID_ARG : Null / incorrect protocomm instance pointer

### Unions

union protocomm_httpd_config_data_t
  #include <protocomm_httpd.h>

  Protocomm HTTPD Configuration Data

  Public Members

  void *handle

    HTTP Server Handle, if ext_handle_provided is set to true

  protocomm_http_server_config_t config

    HTTP Server Configuration, if a server is not already active

### Structures

struct protocomm_http_server_config_t

  Config parameters for protocomm HTTP server.

  Public Members

  uint16_t port

    Port on which the HTTP server will listen

  size_t stack_size

    Stack size of server task, adjusted depending upon stack usage of endpoint handler

  unsigned task_priority

    Priority of server task

struct protocomm_httpd_config_t

  Config parameters for protocomm HTTP server.

  Public Members

  bool ext_handle_provided

    Flag to indicate of an external HTTP Server Handle has been provided. In such as case, protocomm will use the same HTTP Server and not start a new one internally.

  protocomm_httpd_config_data_t data

    Protocomm HTTPD Configuration Data

### Macros

PROTOCOMM_HTTPD_DEFAULT_CONFIG()

### Header File

- components/protocomm/include/transports/protocomm_ble.h

- This header file can be included with:

  >     #include "protocomm_ble.h"

- This header file is a part of the API provided by the `protocomm` component. To declare that your component depends on `protocomm`, add the following to your CMakeLists.txt:

  >     REQUIRES protocomm

  > or

  >     PRIV_REQUIRES protocomm

### Functions

esp_err_t protocomm_ble_start(protocomm_t *pc, const protocomm_ble_config_t *config)

  Start Bluetooth Low Energy based transport layer for provisioning.

  Initialize and start required BLE service for provisioning. This includes the initialization for characteristics/service for BLE.

  参数:

    - pc -- [in] Protocomm instance pointer obtained from protocomm_new()

    - config -- [in] Pointer to config structure for initializing BLE

  返回:

    - ESP_OK : Success

    - ESP_FAIL : Simple BLE start error

    - ESP_ERR_NO_MEM : Error allocating memory for internal resources

    - ESP_ERR_INVALID_STATE : Error in ble config

    - ESP_ERR_INVALID_ARG : Null arguments

esp_err_t protocomm_ble_stop(protocomm_t *pc)

  Stop Bluetooth Low Energy based transport layer for provisioning.

  Stops service/task responsible for BLE based interactions for provisioning

  备注

  You might want to optionally reclaim memory from Bluetooth. Refer to the documentation of `esp_bt_mem_release` in that case.

  参数:

    pc -- [in] Same protocomm instance that was passed to protocomm_ble_start()

  返回:

    - ESP_OK : Success

    - ESP_FAIL : Simple BLE stop error

    - ESP_ERR_INVALID_ARG : Null / incorrect protocomm instance

### Structures

struct name_uuid

  This structure maps handler required by protocomm layer to UUIDs which are used to uniquely identify BLE characteristics from a smartphone or a similar client device.

  Public Members

  const char *name

    Name of the handler, which is passed to protocomm layer

  uint16_t uuid

    UUID to be assigned to the BLE characteristic which is mapped to the handler

struct protocomm_ble_event_t

  Structure for BLE events in Protocomm.

  Public Members

  uint16_t evt_type

    This field indicates the type of BLE event that occurred.

  uint16_t conn_handle

    The handle of the relevant connection.

  uint16_t conn_status

    The status of the connection attempt; o 0: the connection was successfully established. o BLE host error code: the connection attempt failed for the specified reason.

  uint16_t disconnect_reason

    Return code indicating the reason for the disconnect.

struct protocomm_ble_config

  Config parameters for protocomm BLE service.

  Public Members

  char device_name[MAX_BLE_DEVNAME_LEN + 1]

    BLE device name being broadcast at the time of provisioning

  uint8_t service_uuid[BLE_UUID128_VAL_LENGTH]

    128 bit UUID of the provisioning service

  uint8_t *manufacturer_data

    BLE device manufacturer data pointer in advertisement

  ssize_t manufacturer_data_len

    BLE device manufacturer data length in advertisement

  ssize_t nu_lookup_count

    Number of entries in the Name-UUID lookup table

  protocomm_ble_name_uuid_t *nu_lookup

    Pointer to the Name-UUID lookup table

  unsigned ble_bonding

    BLE bonding

  unsigned ble_sm_sc

    BLE security flag

  unsigned ble_link_encryption

    BLE security flag

  uint8_t *ble_addr

    BLE address

  unsigned keep_ble_on

    Flag to keep BLE on

  unsigned ble_notify

    BLE characteristic notify flag

### Macros

MAX_BLE_DEVNAME_LEN

  BLE device name cannot be larger than this value 31 bytes (max scan response size) - 1 byte (length) - 1 byte (type) = 29 bytes

BLE_UUID128_VAL_LENGTH

MAX_BLE_MANUFACTURER_DATA_LEN

  Theoretically, the limit for max manufacturer length remains same as BLE device name i.e. 31 bytes (max scan response size) - 1 byte (length) - 1 byte (type) = 29 bytes However, manufacturer data goes along with BLE device name in scan response. So, it is important to understand the actual length should be smaller than (29 - (BLE device name length) - 2).

BLE_ADDR_LEN

### Type Definitions

typedef struct name_uuid protocomm_ble_name_uuid_t

  This structure maps handler required by protocomm layer to UUIDs which are used to uniquely identify BLE characteristics from a smartphone or a similar client device.

typedef struct protocomm_ble_config protocomm_ble_config_t

  Config parameters for protocomm BLE service.

### Enumerations

enum protocomm_transport_ble_event_t

  Events generated by BLE transport.

  These events are generated when the BLE transport is paired and disconnected.

  Values:

  enumerator PROTOCOMM_TRANSPORT_BLE_CONNECTED
  enumerator PROTOCOMM_TRANSPORT_BLE_DISCONNECTED

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