OVMS3-idf/components/esp_https_server/src/https_server.c

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// Copyright 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.
#include <string.h>
#include "esp_https_server.h"
#include "openssl/ssl.h"
#include "esp_log.h"
#include "sdkconfig.h"
const static char *TAG = "esp_https_server";
/**
* SSL socket close handler
*
* @param[in] ctx - session transport context (SSL context we stored there)
*/
static void httpd_ssl_close(void *ctx)
{
assert(ctx != NULL);
SSL_shutdown(ctx);
SSL_free(ctx);
ESP_LOGD(TAG, "Secure socket closed");
}
/**
* SSL socket pending-check function
*
* @param server
* @param sockfd
* @return number of pending bytes, negative on error
*/
static int httpd_ssl_pending(httpd_handle_t server, int sockfd)
{
SSL *ssl = httpd_sess_get_transport_ctx(server, sockfd);
assert(ssl != NULL);
return SSL_pending(ssl);
}
/**
* Receive from a SSL socket
*
* @param server
* @param sockfd
* @param buf
* @param buf_len
* @param flags
* @return bytes read, negative on error
*/
static int httpd_ssl_recv(httpd_handle_t server, int sockfd, char *buf, size_t buf_len, int flags)
{
SSL *ssl = httpd_sess_get_transport_ctx(server, sockfd);
assert(ssl != NULL);
return SSL_read(ssl, buf, buf_len);
}
/**
* Send to a SSL socket
*
* @param server
* @param sockfd
* @param buf
* @param buf_len
* @param flags
* @return bytes sent, negative on error
*/
static int httpd_ssl_send(httpd_handle_t server, int sockfd, const char *buf, size_t buf_len, int flags)
{
SSL *ssl = httpd_sess_get_transport_ctx(server, sockfd);
assert(ssl != NULL);
return SSL_write(ssl, buf, buf_len);
}
/**
* Open a SSL socket for the server.
* The fd is already open and ready to read / write raw data.
*
* @param server
* @param sockfd - raw socket fd
* @return success
*/
static esp_err_t httpd_ssl_open(httpd_handle_t server, int sockfd)
{
assert(server != NULL);
// Retrieve the SSL context from the global context field (set in config)
SSL_CTX *global_ctx = httpd_get_global_transport_ctx(server);
assert(global_ctx != NULL);
SSL *ssl = SSL_new(global_ctx);
if (NULL == ssl) {
ESP_LOGE(TAG, "SSL_new ret NULL (out of memory)");
return ESP_ERR_NO_MEM;
}
if (1 != SSL_set_fd(ssl, sockfd)) {
ESP_LOGE(TAG, "fail to set SSL fd");
goto teardown;
}
ESP_LOGD(TAG, "SSL accept");
if (1 != SSL_accept(ssl)) {
ESP_LOGW(TAG, "fail to SSL_accept - handshake error");
goto teardown;
}
// Store the SSL session into the context field of the HTTPD session object
httpd_sess_set_transport_ctx(server, sockfd, ssl, httpd_ssl_close);
// Set rx/tx/pending override functions
httpd_sess_set_send_override(server, sockfd, httpd_ssl_send);
httpd_sess_set_recv_override(server, sockfd, httpd_ssl_recv);
httpd_sess_set_pending_override(server, sockfd, httpd_ssl_pending);
// all access should now go through SSL
ESP_LOGD(TAG, "Secure socket open");
return ESP_OK;
teardown:
SSL_free(ssl);
return ESP_FAIL;
}
/**
* Tear down the HTTPD global transport context
*
* @param ctx
*/
static void free_secure_context(void *ctx)
{
assert(ctx != NULL);
ESP_LOGI(TAG, "Server shuts down, releasing SSL context");
SSL_CTX_free(ctx);
}
/**
* Create and perform basic init of a SSL_CTX, or return NULL on failure
*
* @return ctx or null
*/
static SSL_CTX *create_secure_context(const struct httpd_ssl_config *config)
{
SSL_CTX *ctx = NULL;
ESP_LOGD(TAG, "SSL server context create");
ctx = SSL_CTX_new(TLS_server_method());
if (NULL != ctx) {
//region SSL ctx alloc'd
ESP_LOGD(TAG, "SSL ctx set own cert");
if (SSL_CTX_use_certificate_ASN1(ctx, config->cacert_len, config->cacert_pem)
&& SSL_CTX_use_PrivateKey_ASN1(0, ctx, config->prvtkey_pem, (long) config->prvtkey_len)) {
return ctx;
}
else {
ESP_LOGE(TAG, "Failed to set certificate");
SSL_CTX_free(ctx);
ctx = NULL;
}
} else {
ESP_LOGE(TAG, "Failed to create SSL context");
}
return NULL;
}
/** Start the server */
esp_err_t httpd_ssl_start(httpd_handle_t *pHandle, struct httpd_ssl_config *config)
{
assert(config != NULL);
assert(pHandle != NULL);
ESP_LOGI(TAG, "Starting server");
if (HTTPD_SSL_TRANSPORT_SECURE == config->transport_mode) {
SSL_CTX *ctx = create_secure_context(config);
if (!ctx) {
return ESP_FAIL;
}
ESP_LOGD(TAG, "SSL context ready");
// set SSL specific config
config->httpd.global_transport_ctx = ctx;
config->httpd.global_transport_ctx_free_fn = free_secure_context;
config->httpd.open_fn = httpd_ssl_open; // the open function configures the created SSL sessions
config->httpd.server_port = config->port_secure;
} else {
ESP_LOGD(TAG, "SSL disabled, using plain HTTP");
config->httpd.server_port = config->port_insecure;
}
httpd_handle_t handle = NULL;
esp_err_t ret = httpd_start(&handle, &config->httpd);
if (ret != ESP_OK) return ret;
*pHandle = handle;
ESP_LOGI(TAG, "Server listening on port %d", config->httpd.server_port);
return ESP_OK;
}
/** Stop the server */
void httpd_ssl_stop(httpd_handle_t handle)
{
httpd_stop(handle);
}