API.cpp

#include "API.hpp"
 
namespace fw
{
    API::API(fw::Firewall *firewall, const char *cert, const char *key, const char *username, const char *password, const String ip, const uint16_t port)
    {
        this->firewall = firewall;
        this->api_ip = ip;
        this->api_port = port;
        if (this->setup_auth(username, password) == ERROR)
            endless_loop();
#ifdef ESP8266
        this->server = new ESP8266WebServerSecure(port);
        this->serverCache = new ServerSessions(5);
#else
        this->server = new WebServer(port);
#endif
        this->setup_routing(cert, key);
        this->server->begin();
        Serial.printf("%s endpoints -> %s/api\n", TAG, this->get_url_base().c_str());
#if !defined(ESP8266)
        while (true)
        {
            this->server->handleClient();
            // https://docs.espressif.com/projects/arduino-esp32/en/latest/esp-idf_component.html
            sleep(1);
        }
#endif
    }
 
    API::~API()
    {
        this->server->stop();
    }
 
#ifdef ESP8266
    void API::handle_client()
    {
        this->server->handleClient();
    }
#endif
 
    String API::get_url_base()
    {
#ifdef ESP8266
        return "https://" + this->api_ip + ":" + this->api_port;
#else
        return "http://" + this->api_ip + ":" + this->api_port;
#endif
    }
 
    ok_t API::setup_auth(const char *username, const char *password)
    {
        if (!username || *username == 0x00 || strlen(username) > CREDENTIALS_LENGTH)
        {
            Serial.printf("%s Username too long or missing!\n", TAG);
            return ERROR;
        }
        strncpy(credentials.username, username, CREDENTIALS_LENGTH);
        if (!password || *password == 0x00 || strlen(password) > CREDENTIALS_LENGTH)
        {
            Serial.printf("%s Password too long or missing!\n", TAG);
            return ERROR;
        }
        strncpy(credentials.password, password, CREDENTIALS_LENGTH);
        return SUCCESS;
    }
 
    auth_t API::check_auth()
    {
        if (server->authenticate(this->credentials.username, this->credentials.password))
        {
            return AUTHENTICATED;
        }
        this->json_message_response("unauthorized", 403);
        return DENIED;
    }
 
    void API::setup_routing(const char *cert, const char *key)
    {
#ifdef ESP8266
        this->server->getServer().setRSACert(new BearSSL::X509List(cert), new BearSSL::PrivateKey(key));
        this->server->getServer().setCache(serverCache);
#endif
        this->server->on("/api/firewall/rules", HTTP_GET, std::bind(&API::get_firewall_rules_handler, this));
        this->server->on(UriBraces("/api/firewall/rules/{}"), HTTP_GET, std::bind(&API::get_firewall_rule_handler, this));
        this->server->on("/api/firewall/rules", HTTP_POST, std::bind(&API::post_firewall_handler, this));
        this->server->on(UriBraces("/api/firewall/rules/{}"), HTTP_PUT, std::bind(&API::put_firewall_handler, this));
        this->server->on(UriBraces("/api/firewall/rules/{}"), HTTP_DELETE, std::bind(&API::delete_firewall_handler, this));
        this->server->on("/api", HTTP_GET, std::bind(&API::get_endpoint_list_handler, this));
        this->server->onNotFound(std::bind(&API::not_found_handler, this));
 
        add_endpoint_to_list("/api/firewall/rules", "GET", "Get all Firewall Rules");
        add_endpoint_to_list("/api/firewall/rules/<key>", "GET", "Get Firewall Rule by key");
        add_endpoint_to_list("/api/firewall/rules", "POST", "Create Firewall Rule");
        add_endpoint_to_list("/api/firewall/rules/<key>", "PUT", "Update Firewall Rule by key");
        add_endpoint_to_list("/api/firewall/rules/<key>", "DELETE", "Delete Firewall Rule by key");
    }
 
    void API::add_endpoint_to_list(const String uri, const char *method, const char *description)
    {
        api_endpoint_t *temp;
        const String url = get_url_base() + uri;
 
        api_endpoint_t *api_ptr = (api_endpoint_t *)malloc(sizeof(api_endpoint_t));
        strncpy(api_ptr->uri, url.c_str(), sizeof(api_ptr->uri));
        strncpy(api_ptr->method, method, sizeof(api_ptr->method));
        strncpy(api_ptr->description, description, sizeof(api_ptr->description));
 
        if (this->endpoint_head == NULL)
        {
            this->endpoint_head = api_ptr;
            api_ptr->next = NULL;
            return;
        }
        temp = this->endpoint_head;
        while (temp->next != NULL)
        {
            temp = temp->next;
        }
        temp->next = api_ptr;
        api_ptr->next = NULL;
        return;
    }
 
    void API::not_found_handler()
    {
        this->json_message_response("see " + get_url_base() + "/api for available routes", 404);
    }
 
    void API::get_endpoint_list_handler()
    {
        this->json_array_response(this->construct_json_api(), 200);
    }
 
    void API::get_firewall_rule_handler()
    {
        if (this->check_auth() == DENIED)
            return;
        String param = this->server->pathArg(0);
        int rule_number = atoi(param.c_str());
        firewall_rule_t *rule_ptr = firewall->get_rule_from_firewall(rule_number);
        if (rule_ptr == NULL)
            this->json_message_response("rule does not exist", 404);
        else
            this->json_generic_response(this->construct_json_firewall_rule(rule_ptr), 200);
    }
 
    void API::get_firewall_rules_handler()
    {
        if (this->check_auth() == DENIED)
            return;
        this->json_array_response(this->construct_json_firewall(), 200);
    }
 
    void API::post_firewall_handler()
    {
        if (this->check_auth() == DENIED)
            return;
        if (request_has_all_firewall_parameter())
        {
            String args[IPV4ADDRESS_LENGTH] = {};
            for (uint8_t i = 0; i < firewall_fields_amount; i++)
            {
                args[i] = this->server->arg(firewall_fields[i]);
            }
            firewall_rule_t *rule_ptr = firewall->add_rule_to_firewall(args);
            this->json_generic_response(this->construct_json_firewall_rule(rule_ptr), 201);
        }
        else
        {
            this->json_message_response("not enough parameter provided", 400);
        }
    }
 
    void API::put_firewall_handler()
    {
        if (this->check_auth() == DENIED)
            return;
        String param = this->server->pathArg(0);
        int rule_number = atoi(param.c_str());
        if (request_has_all_firewall_parameter())
        {
            String args[IPV4ADDRESS_LENGTH] = {};
            for (uint8_t i = 0; i < firewall_fields_amount; i++)
            {
                args[i] = this->server->arg(firewall_fields[i]);
            }
            firewall_rule_t *rule_ptr = firewall->update_rule_of_firewall(args, rule_number);
            if (rule_ptr == NULL)
                this->json_message_response("rule does not exist", 404);
            else
                this->json_generic_response(this->construct_json_firewall_rule(rule_ptr), 200);
        }
        else
        {
            this->json_message_response("not enough parameter provided", 400);
        }
    }
 
    void API::delete_firewall_handler()
    {
        if (this->check_auth() == DENIED)
            return;
        String param = this->server->pathArg(0);
        int rule_number = atoi(param.c_str());
        if (firewall->delete_rule_from_firewall(rule_number) == SUCCESS)
            this->json_message_response("firewall rule deleted", 200);
        else
            this->json_message_response("cannot delete firewall rule", 500);
    }
 
    bool API::request_has_all_firewall_parameter()
    {
        if (!this->server->args())
            return false;
        for (uint8_t i = 0; i < firewall_fields_amount; i++)
        {
            if (i != KEY && !this->server->hasArg(firewall_fields[i]))
                return false;
        }
        return true;
    }
 
    String API::json_new_attribute(String key, String value, bool last)
    {
        String json_string;
        json_string += "\"" + key + "\": \"" + value + "\"";
        if (!last)
            json_string += ",";
        return json_string;
    }
 
    String API::json_new_attribute(String key, uint32_t value, bool last)
    {
        return json_new_attribute(key, String(value), last);
    }
 
    void API::json_generic_response(String serialized_string, const uint16_t response_code)
    {
        this->server->send(response_code, json_response_type, serialized_string);
    }
 
    void API::json_array_response(String serialized_string, const uint16_t response_code)
    {
        this->server->send(response_code, json_response_type, "[" + serialized_string + "]");
    }
 
    void API::json_message_response(String message, const uint16_t response_code)
    {
        String serialized_string = "{";
        serialized_string += json_new_attribute("message", message, true);
        serialized_string += "}";
        this->server->send(response_code, json_response_type, serialized_string);
    }
 
    String API::construct_json_firewall_rule(firewall_rule_t *rule_ptr)
    {
        String serialized_string = "{";
        serialized_string += json_new_attribute(firewall_fields[KEY], rule_ptr->key);
        serialized_string += json_new_attribute(firewall_fields[IP], rule_ptr->ip);
        serialized_string += json_new_attribute(firewall_fields[PORT_FROM], rule_ptr->port_from);
        serialized_string += json_new_attribute(firewall_fields[PORT_TO], rule_ptr->port_to);
        serialized_string += json_new_attribute(firewall_fields[PROTOCOL], protocol_to_string(rule_ptr->protocol));
        serialized_string += json_new_attribute(firewall_fields[TARGET], target_to_string(rule_ptr->target), true);
        serialized_string += "}";
        return serialized_string;
    }
 
    String API::construct_json_firewall()
    {
        firewall_rule_t *rule_ptr = firewall->get_rule_head();
        String serialized_string;
        while (rule_ptr != NULL)
        {
            serialized_string += construct_json_firewall_rule(rule_ptr);
            rule_ptr = rule_ptr->next;
            if (rule_ptr != NULL)
                serialized_string += ",";
        }
        return serialized_string;
    }
 
    String API::construct_json_api_endpoint(api_endpoint_t *api_ptr)
    {
        String serialized_string = "{";
        serialized_string += json_new_attribute("endpoint", api_ptr->uri);
        serialized_string += json_new_attribute("description", api_ptr->description);
        serialized_string += json_new_attribute("method", api_ptr->method, true);
        serialized_string += "}";
        return serialized_string;
    }
 
    String API::construct_json_api()
    {
        api_endpoint_t *api_ptr = this->endpoint_head;
        String serialized_string;
        while (api_ptr != NULL)
        {
            serialized_string += construct_json_api_endpoint(api_ptr);
            api_ptr = api_ptr->next;
            if (api_ptr != NULL)
                serialized_string += ",";
        }
        return serialized_string;
    }
}