wolfssl/IDE/ARDUINO/sketches/wolfssl_client/wolfssl_client.ino

/* wolfssl_client.ino
 *
 * Copyright (C) 2006-2023 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * wolfSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
 */

/*
 This was original tested with Intel Galileo acting as the Client, with a 
laptop acting as a server using the server example provided in examples/server.
Legacy Ardunio v1.86 was used to compile and program the Galileo 
*/

#define USE_CERT_BUFFERS_2048
#include <wolfssl.h>
#include <wolfssl/ssl.h>
#include <Ethernet.h>
#include <wolfssl/certs_test.h>


const char host[] = "192.168.1.148"; /* server to connect to */
const int port = 11111; /* port on server to connect to */

int EthernetSend(WOLFSSL* ssl, char* msg, int sz, void* ctx);
int EthernetReceive(WOLFSSL* ssl, char* reply, int sz, void* ctx);
int reconnect = 10;

EthernetClient client;

WOLFSSL_CTX* ctx = NULL;
WOLFSSL* ssl = NULL;

void setup() {
    WOLFSSL_METHOD* method;
    /* Initialize Return Code */
    int rc;
    Serial.begin(9600);
    /* Delay need to ensure connection to server */
    delay(4000);

    method = wolfTLSv1_2_client_method();
    if (method == NULL) {
        Serial.println("unable to get method");
    return;
    }
    ctx = wolfSSL_CTX_new(method);
    if (ctx == NULL) {
        Serial.println("unable to get ctx");
    return;
    }
    /* initialize wolfSSL using callback functions */
    wolfSSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, 0);
    rc = wolfSSL_CTX_load_verify_buffer(ctx, ca_cert_der_2048,\
                                        sizeof_ca_cert_der_2048,\
                                        WOLFSSL_FILETYPE_ASN1);
    Serial.print("\n\n Return code of load_verify is:");
    Serial.println(rc);
    Serial.println("");
    rc = wolfSSL_CTX_use_certificate_buffer(ctx, client_cert_der_2048,\
                                            sizeof_client_cert_der_2048,\
                                            WOLFSSL_FILETYPE_ASN1);
    Serial.print("\n\n Return code of use_certificate_buffer is:");
    Serial.println(rc);
    Serial.println("");
    rc = wolfSSL_CTX_use_PrivateKey_buffer(ctx, client_key_der_2048,\
                                            sizeof_client_key_der_2048,\
                                            WOLFSSL_FILETYPE_ASN1);
    Serial.print("\n\n Return code of use_PrivateKey_buffer is:");
    Serial.println(rc);
    Serial.println("");
    wolfSSL_SetIOSend(ctx, EthernetSend);
    wolfSSL_SetIORecv(ctx, EthernetReceive);
    return;
}

int EthernetSend(WOLFSSL* ssl, char* msg, int sz, void* ctx) {
    int sent = 0;
    sent = client.write((byte*)msg, sz);
    return sent;
}

int EthernetReceive(WOLFSSL* ssl, char* reply, int sz, void* ctx) {
    int ret = 0;
    while (client.available() > 0 && ret < sz) {
        reply[ret++] = client.read();
    }
    return ret;
}

void loop() {
    int err            = 0;
    int input          = 0;
    int total_input    = 0;
    char msg[32]       = "hello wolfssl!";
    int msgSz          = (int)strlen(msg);
    char errBuf[80];
    char reply[80];
    const char* cipherName;
    if (reconnect) {
        reconnect--;
        if (client.connect(host, port)) {
            Serial.print("Connected to ");
            Serial.println(host);
            ssl = wolfSSL_new(ctx);
            if (ssl == NULL) {
                Serial.println("Unable to allocate SSL object");
                return;
            }
            err = wolfSSL_connect(ssl);
            if (err != WOLFSSL_SUCCESS) {
                err = wolfSSL_get_error(ssl, 0);
                wolfSSL_ERR_error_string(err, errBuf);
                Serial.print("TLS Connect Error: ");
                Serial.println(errBuf);
            }
            Serial.print("SSL version is ");
            Serial.println(wolfSSL_get_version(ssl));
            cipherName = wolfSSL_get_cipher(ssl);
            Serial.print("SSL cipher suite is ");
            Serial.println(cipherName);
            if ((wolfSSL_write(ssl, msg, msgSz)) == msgSz) {
                Serial.print("Server response: ");
                /* wait for data */
                while (!client.available()) {}
                /* read data */
                while (wolfSSL_pending(ssl)) {
                    input = wolfSSL_read(ssl, reply, sizeof(reply) - 1);
                    total_input += input;
                    if (input < 0) {
                        err = wolfSSL_get_error(ssl, 0);
                        wolfSSL_ERR_error_string(err, errBuf);
                        Serial.print("TLS Read Error: ");
                        Serial.println(errBuf);
                        break;
                    } 
                    else if (input > 0) {
                        reply[input] = '\0';
                        Serial.print(reply);
                    }
                    else {
                        Serial.println();
                    }
                } 
            }
            else {
                err = wolfSSL_get_error(ssl, 0);
                wolfSSL_ERR_error_string(err, errBuf);
                Serial.print("TLS Write Error: ");
                Serial.println(errBuf);
            }
            wolfSSL_shutdown(ssl);
            wolfSSL_free(ssl);
            client.stop();
            Serial.println("Connection complete.");
            reconnect = 0;
        }
        else {
            Serial.println("Trying to reconnect...");
        }
    }
    delay(1000);
}