text: // Copyright 2019 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 <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <unistd.h>
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netdb.h>
  
  #include <http_parser.h>
  #include "esp_tls.h"
  #include "esp_tls_error_capture_internal.h"
  #include <errno.h>
  static const char *TAG = "esp-tls";
  
  #ifdef CONFIG_ESP_TLS_USING_MBEDTLS
  #include "esp_tls_mbedtls.h"
  #elif CONFIG_ESP_TLS_USING_WOLFSSL
  #include "esp_tls_wolfssl.h"
  #endif
  
  #ifdef ESP_PLATFORM
  #include <esp_log.h>
  #else
  #define ESP_LOGD(TAG, ...) //printf(__VA_ARGS__);
  #define ESP_LOGE(TAG, ...) printf(__VA_ARGS__);
  #endif
  
  #ifdef CONFIG_ESP_TLS_USING_MBEDTLS
  #define _esp_create_ssl_handle              esp_create_mbedtls_handle
  #define _esp_tls_handshake                  esp_mbedtls_handshake
  #define _esp_tls_read                       esp_mbedtls_read
  #define _esp_tls_write                      esp_mbedtls_write
  #define _esp_tls_conn_delete                esp_mbedtls_conn_delete
  #ifdef CONFIG_ESP_TLS_SERVER
  #define _esp_tls_server_session_create      esp_mbedtls_server_session_create
  #define _esp_tls_server_session_delete      esp_mbedtls_server_session_delete
  #endif  /* CONFIG_ESP_TLS_SERVER */
  #define _esp_tls_get_bytes_avail            esp_mbedtls_get_bytes_avail
  #define _esp_tls_init_global_ca_store       esp_mbedtls_init_global_ca_store
  #define _esp_tls_set_global_ca_store        esp_mbedtls_set_global_ca_store                 /*!< Callback function for setting global CA store data for TLS/SSL */
  #define _esp_tls_get_global_ca_store        esp_mbedtls_get_global_ca_store
  #define _esp_tls_free_global_ca_store       esp_mbedtls_free_global_ca_store                /*!< Callback function for freeing global ca store for TLS/SSL */
  #elif CONFIG_ESP_TLS_USING_WOLFSSL /* CONFIG_ESP_TLS_USING_MBEDTLS */
  #define _esp_create_ssl_handle              esp_create_wolfssl_handle
  #define _esp_tls_handshake                  esp_wolfssl_handshake
  #define _esp_tls_read                       esp_wolfssl_read
  #define _esp_tls_write                      esp_wolfssl_write
  #define _esp_tls_conn_delete                esp_wolfssl_conn_delete
  #define _esp_tls_get_bytes_avail            esp_wolfssl_get_bytes_avail
  #define _esp_tls_init_global_ca_store       esp_wolfssl_init_global_ca_store
  #define _esp_tls_set_global_ca_store        esp_wolfssl_set_global_ca_store                 /*!< Callback function for setting global CA store data for TLS/SSL */
  #define _esp_tls_free_global_ca_store       esp_wolfssl_free_global_ca_store                /*!< Callback function for freeing global ca store for TLS/SSL */
  #else   /* ESP_TLS_USING_WOLFSSL */
  #error "No TLS stack configured"
  #endif
  
  static esp_err_t create_ssl_handle(const char *hostname, size_t hostlen, const void *cfg, esp_tls_t *tls)
  {
      return _esp_create_ssl_handle(hostname, hostlen, cfg, tls);
  }
  
  static esp_err_t esp_tls_handshake(esp_tls_t *tls, const esp_tls_cfg_t *cfg)
  {
      return _esp_tls_handshake(tls, cfg);
  }
  
  static ssize_t tcp_read(esp_tls_t *tls, char *data, size_t datalen)
  {
      return recv(tls->sockfd, data, datalen, 0);
  }
  
  static ssize_t tcp_write(esp_tls_t *tls, const char *data, size_t datalen)
  {
      return send(tls->sockfd, data, datalen, 0);
  }
  
  /**
   * @brief      Close the TLS connection and free any allocated resources.
   */
  void esp_tls_conn_delete(esp_tls_t *tls)
  {
      esp_tls_conn_destroy(tls);
  }
  
  int esp_tls_conn_destroy(esp_tls_t *tls)
  {
      if (tls != NULL) {
          int ret = 0;
          _esp_tls_conn_delete(tls);
          if (tls->sockfd >= 0) {
              ret = close(tls->sockfd);
          }
          free(tls->error_handle);
          free(tls);
          return ret;
      }
      return -1; // invalid argument
  }
  
  esp_tls_t *esp_tls_init(void)
  {
      esp_tls_t *tls = (esp_tls_t *)calloc(1, sizeof(esp_tls_t));
      if (!tls) {
          return NULL;
      }
      tls->error_handle = calloc(1, sizeof(esp_tls_last_error_t));
      if (!tls->error_handle) {
          free(tls);
          return NULL;
      }
  #ifdef CONFIG_ESP_TLS_USING_MBEDTLS
      tls->server_fd.fd = -1;
  #endif
      tls->sockfd = -1;
      return tls;
  }
  
  static esp_err_t resolve_host_name(const char *host, size_t hostlen, struct addrinfo **address_info)
  {
      struct addrinfo hints;
      memset(&hints, 0, sizeof(hints));
      hints.ai_family = AF_UNSPEC;
      hints.ai_socktype = SOCK_STREAM;
  
      char *use_host = strndup(host, hostlen);
      if (!use_host) {
          return ESP_ERR_NO_MEM;
      }
  
      ESP_LOGD(TAG, "host:%s: strlen %lu", use_host, (unsigned long)hostlen);
      if (getaddrinfo(use_host, NULL, &hints, address_info)) {
          ESP_LOGE(TAG, "couldn't get hostname for :%s:", use_host);
          free(use_host);
          return ESP_ERR_ESP_TLS_CANNOT_RESOLVE_HOSTNAME;
      }
      free(use_host);
      return ESP_OK;
  }
  
  static void ms_to_timeval(int timeout_ms, struct timeval *tv)
  {
      tv->tv_sec = timeout_ms / 1000;
      tv->tv_usec = (timeout_ms % 1000) * 1000;
  }
  
  static esp_err_t esp_tcp_connect(const char *host, int hostlen, int port, int *sockfd, const esp_tls_t *tls, const esp_tls_cfg_t *cfg)
  {
      esp_err_t ret;
      struct addrinfo *addrinfo;
      if ((ret = resolve_host_name(host, hostlen, &addrinfo)) != ESP_OK) {
          return ret;
      }
  
      int fd = socket(addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol);
      if (fd < 0) {
          ESP_LOGE(TAG, "Failed to create socket (family %d socktype %d protocol %d)", addrinfo->ai_family, addrinfo->ai_socktype, addrinfo->ai_protocol);
          ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_SYSTEM, errno);
          ret = ESP_ERR_ESP_TLS_CANNOT_CREATE_SOCKET;
          goto err_freeaddr;
      }
  
      void *addr_ptr;
      if (addrinfo->ai_family == AF_INET) {
          struct sockaddr_in *p = (struct sockaddr_in *)addrinfo->ai_addr;
          p->sin_port = htons(port);
          addr_ptr = p;
      } else if (addrinfo->ai_family == AF_INET6) {
          struct sockaddr_in6 *p = (struct sockaddr_in6 *)addrinfo->ai_addr;
          p->sin6_port = htons(port);
          p->sin6_family = AF_INET6;
          addr_ptr = p;
      } else {
          ESP_LOGE(TAG, "Unsupported protocol family %d", addrinfo->ai_family);
          ret = ESP_ERR_ESP_TLS_UNSUPPORTED_PROTOCOL_FAMILY;
          goto err_freesocket;
      }
  
      if (cfg) {
          if (cfg->timeout_ms >= 0) {
              struct timeval tv;
              ms_to_timeval(cfg->timeout_ms, &tv);
              setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
              setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
          }
          if (cfg->non_block) {
              int flags = fcntl(fd, F_GETFL, 0);
              ret = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
              if (ret < 0) {
                  ESP_LOGE(TAG, "Failed to configure the socket as non-blocking (errno %d)", errno);
                  goto err_freesocket;
              }
          }
      }
  
      ret = connect(fd, addr_ptr, addrinfo->ai_addrlen);
      if (ret < 0 && !(errno == EINPROGRESS && cfg && cfg->non_block)) {
  
          ESP_LOGE(TAG, "Failed to connnect to host (errno %d)", errno);
          ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_SYSTEM, errno);
          ret = ESP_ERR_ESP_TLS_FAILED_CONNECT_TO_HOST;
          goto err_freesocket;
      }
  
      *sockfd = fd;
      freeaddrinfo(addrinfo);
      return ESP_OK;
  
  err_freesocket:
      close(fd);
  err_freeaddr:
      freeaddrinfo(addrinfo);
      return ret;
  }
  
  static int esp_tls_low_level_conn(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls)
  {
      if (!tls) {
          ESP_LOGE(TAG, "empty esp_tls parameter");
          return -1;
      }
      esp_err_t esp_ret;
      /* These states are used to keep a tab on connection progress in case of non-blocking connect,
      and in case of blocking connect these cases will get executed one after the other */
      switch (tls->conn_state) {
      case ESP_TLS_INIT:
          tls->sockfd = -1;
          if (cfg != NULL) {
  #ifdef CONFIG_ESP_TLS_USING_MBEDTLS
              mbedtls_net_init(&tls->server_fd);
  #endif
              tls->is_tls = true;
          }
          if ((esp_ret = esp_tcp_connect(hostname, hostlen, port, &tls->sockfd, tls, cfg)) != ESP_OK) {
              ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_ESP, esp_ret);
              return -1;
          }
          if (!cfg) {
              tls->read = tcp_read;
              tls->write = tcp_write;
              ESP_LOGD(TAG, "non-tls connection established");
              return 1;
          }
          if (cfg->non_block) {
              FD_ZERO(&tls->rset);
              FD_SET(tls->sockfd, &tls->rset);
              tls->wset = tls->rset;
          }
          tls->conn_state = ESP_TLS_CONNECTING;
      /* falls through */
      case ESP_TLS_CONNECTING:
          if (cfg->non_block) {
              ESP_LOGD(TAG, "connecting...");
              struct timeval tv;
              ms_to_timeval(cfg->timeout_ms, &tv);
  
              /* In case of non-blocking I/O, we use the select() API to check whether
                 connection has been established or not*/
              if (select(tls->sockfd + 1, &tls->rset, &tls->wset, NULL,
                         cfg->timeout_ms>0 ? &tv : NULL) == 0) {
                  ESP_LOGD(TAG, "select() timed out");
                  return 0;
              }
              if (FD_ISSET(tls->sockfd, &tls->rset) || FD_ISSET(tls->sockfd, &tls->wset)) {
                  int error;
                  unsigned int len = sizeof(error);
                  /* pending error check */
                  if (getsockopt(tls->sockfd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
                      ESP_LOGD(TAG, "Non blocking connect failed");
                      ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_SYSTEM, errno);
                      ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_ESP, ESP_ERR_ESP_TLS_SOCKET_SETOPT_FAILED);
                      tls->conn_state = ESP_TLS_FAIL;
                      return -1;
                  }
              }
          }
          /* By now, the connection has been established */
          esp_ret = create_ssl_handle(hostname, hostlen, cfg, tls);
          if (esp_ret != ESP_OK) {
              ESP_LOGE(TAG, "create_ssl_handle failed");
              ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_ESP, esp_ret);
              tls->conn_state = ESP_TLS_FAIL;
              return -1;
          }
          tls->read = _esp_tls_read;
          tls->write = _esp_tls_write;
          tls->conn_state = ESP_TLS_HANDSHAKE;
      /* falls through */
      case ESP_TLS_HANDSHAKE:
          ESP_LOGD(TAG, "handshake in progress...");
          return esp_tls_handshake(tls, cfg);
          break;
      case ESP_TLS_FAIL:
          ESP_LOGE(TAG, "failed to open a new connection");;
          break;
      default:
          ESP_LOGE(TAG, "invalid esp-tls state");
          break;
      }
      return -1;
  }
  
  /**
   * @brief      Create a new TLS/SSL connection
   */
  esp_tls_t *esp_tls_conn_new(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg)
  {
      esp_tls_t *tls = esp_tls_init();
      if (!tls) {
          return NULL;
      }
      /* esp_tls_conn_new() API establishes connection in a blocking manner thus this loop ensures that esp_tls_conn_new()
         API returns only after connection is established unless there is an error*/
      size_t start = xTaskGetTickCount();
      while (1) {
          int ret = esp_tls_low_level_conn(hostname, hostlen, port, cfg, tls);
          if (ret == 1) {
              return tls;
          } else if (ret == -1) {
              esp_tls_conn_delete(tls);
              ESP_LOGE(TAG, "Failed to open new connection");
              return NULL;
          } else if (ret == 0 && cfg->timeout_ms >= 0) {
              size_t timeout_ticks = pdMS_TO_TICKS(cfg->timeout_ms);
              uint32_t expired = xTaskGetTickCount() - start;
              if (expired >= timeout_ticks) {
                  esp_tls_conn_delete(tls);
                  ESP_LOGE(TAG, "Failed to open new connection in specified timeout");
                  return NULL;
              }
          }
      }
      return NULL;
  }
  
  int esp_tls_conn_new_sync(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls)
  {
      /* esp_tls_conn_new_sync() is a sync alternative to esp_tls_conn_new_async() with symmetric function prototype
      it is an alternative to esp_tls_conn_new() which is left for compatibility reasons */
      size_t start = xTaskGetTickCount();
      while (1) {
          int ret = esp_tls_low_level_conn(hostname, hostlen, port, cfg, tls);
          if (ret == 1) {
              return ret;
          } else if (ret == -1) {
              ESP_LOGE(TAG, "Failed to open new connection");
              return -1;
          } else if (ret == 0 && cfg->timeout_ms >= 0) {
              size_t timeout_ticks = pdMS_TO_TICKS(cfg->timeout_ms);
              uint32_t expired = xTaskGetTickCount() - start;
              if (expired >= timeout_ticks) {
                  ESP_LOGW(TAG, "Failed to open new connection in specified timeout");
                  ESP_INT_EVENT_TRACKER_CAPTURE(tls->error_handle, ERR_TYPE_ESP, ESP_ERR_ESP_TLS_CONNECTION_TIMEOUT);
                  return 0;
              }
          }
      }
      return 0;
  }
  
  /*
   * @brief      Create a new TLS/SSL non-blocking connection
   */
  int esp_tls_conn_new_async(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls)
  {
      return esp_tls_low_level_conn(hostname, hostlen, port, cfg, tls);
  }
  
  static int get_port(const char *url, struct http_parser_url *u)
  {
      if (u->field_data[UF_PORT].len) {
          return strtol(&url[u->field_data[UF_PORT].off], NULL, 10);
      } else {
          if (strncasecmp(&url[u->field_data[UF_SCHEMA].off], "http", u->field_data[UF_SCHEMA].len) == 0) {
              return 80;
          } else if (strncasecmp(&url[u->field_data[UF_SCHEMA].off], "https", u->field_data[UF_SCHEMA].len) == 0) {
              return 443;
          }
      }
      return 0;
  }
  
  /**
   * @brief      Create a new TLS/SSL connection with a given "HTTP" url
   */
  esp_tls_t *esp_tls_conn_http_new(const char *url, const esp_tls_cfg_t *cfg)
  {
      /* Parse URI */
      struct http_parser_url u;
      http_parser_url_init(&u);
      http_parser_parse_url(url, strlen(url), 0, &u);
      esp_tls_t *tls = esp_tls_init();
      if (!tls) {
          return NULL;
      }
      /* Connect to host */
      if (esp_tls_conn_new_sync(&url[u.field_data[UF_HOST].off], u.field_data[UF_HOST].len,
                                get_port(url, &u), cfg, tls) == 1) {
          return tls;
      }
      esp_tls_conn_delete(tls);
      return NULL;
  }
  
  /**
   * @brief      Create a new non-blocking TLS/SSL connection with a given "HTTP" url
   */
  int esp_tls_conn_http_new_async(const char *url, const esp_tls_cfg_t *cfg, esp_tls_t *tls)
  {
      /* Parse URI */
      struct http_parser_url u;
      http_parser_url_init(&u);
      http_parser_parse_url(url, strlen(url), 0, &u);
  
      /* Connect to host */
      return esp_tls_conn_new_async(&url[u.field_data[UF_HOST].off], u.field_data[UF_HOST].len,
                                    get_port(url, &u), cfg, tls);
  }
  
  #ifdef CONFIG_ESP_TLS_USING_MBEDTLS
  
  mbedtls_x509_crt *esp_tls_get_global_ca_store(void)
  {
      return _esp_tls_get_global_ca_store();
  }
  
  #endif /* CONFIG_ESP_TLS_USING_MBEDTLS */
  #ifdef CONFIG_ESP_TLS_SERVER
  /**
   * @brief      Create a server side TLS/SSL connection
   */
  int esp_tls_server_session_create(esp_tls_cfg_server_t *cfg, int sockfd, esp_tls_t *tls)
  {
      return _esp_tls_server_session_create(cfg, sockfd, tls);
  }
  /**
   * @brief      Close the server side TLS/SSL connection and free any allocated resources.
   */
  void esp_tls_server_session_delete(esp_tls_t *tls)
  {
      return _esp_tls_server_session_delete(tls);
  }
  #endif /* CONFIG_ESP_TLS_SERVER */
  
  ssize_t esp_tls_get_bytes_avail(esp_tls_t *tls)
  {
      return _esp_tls_get_bytes_avail(tls);
  }
  
  esp_err_t esp_tls_get_conn_sockfd(esp_tls_t *tls, int *sockfd)
  {
      if (!tls || !sockfd) {
          ESP_LOGE(TAG, "Invalid arguments passed");
          return ESP_ERR_INVALID_ARG;
      }
      *sockfd = tls->sockfd;
      return ESP_OK;
  }
  
  esp_err_t esp_tls_get_and_clear_last_error(esp_tls_error_handle_t h, int *esp_tls_code, int *esp_tls_flags)
  {
      if (!h) {
          return ESP_ERR_INVALID_STATE;
      }
      esp_err_t last_err = h->last_error;
      if (esp_tls_code) {
          *esp_tls_code = h->esp_tls_error_code;
      }
      if (esp_tls_flags) {
          *esp_tls_flags = h->esp_tls_flags;
      }
      memset(h, 0, sizeof(esp_tls_last_error_t));
      return last_err;
  }
  
  esp_err_t esp_tls_init_global_ca_store(void)
  {
      return _esp_tls_init_global_ca_store();
  }
  
  esp_err_t esp_tls_set_global_ca_store(const unsigned char *cacert_pem_buf, const unsigned int cacert_pem_bytes)
  {
      return _esp_tls_set_global_ca_store(cacert_pem_buf, cacert_pem_bytes);
  }
  
  void esp_tls_free_global_ca_store(void)
  {
      return _esp_tls_free_global_ca_store();
  }
  