wolfssl-examples/dtls/client-dtls-resume.c

266 lines
6.9 KiB
C

/*
* client-dtls-resume.c
*
* Copyright (C) 2006-2020 wolfSSL Inc.
*
* This file is part of wolfSSL. (formerly known as CyaSSL)
*
* 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 02110-1301, USA
*
*=============================================================================
*
* Bare-bones example of a DTLS client for instructional/learning purposes.
*/
#include <wolfssl/options.h>
#include <unistd.h>
#include <wolfssl/ssl.h>
#include <netdb.h>
#include <signal.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAXLINE 4096
#define SERV_PORT 11111
static int new_udp_client_socket(WOLFSSL * ssl, const char * host);
static int talk_to_server(WOLFSSL * ssl, const char * msg);
int
main(int argc,
char * argv[])
{
/* standard variables used in a dtls client*/
int sockfd = 0;
int err1;
const char * host = argv[1];
WOLFSSL * ssl = NULL; /* The ssl for original connection. */
WOLFSSL * ssl_res = NULL; /* The ssl for resuming connection. */
WOLFSSL_CTX * ctx = NULL;
WOLFSSL_SESSION * session = NULL;
char cert_array[] = "../certs/ca-cert.pem";
char buffer[80];
char * certs = cert_array;
int ret = 0;
/* variables used in a dtls client for session reuse*/
if (argc != 2) {
printf("usage: udpcli <IP address>\n");
return EXIT_FAILURE;
}
wolfSSL_Init();
/* Un-comment the following line to enable debugging */
/* wolfSSL_Debugging_ON(); */
if ( (ctx = wolfSSL_CTX_new(wolfDTLSv1_2_client_method())) == NULL) {
fprintf(stderr, "wolfSSL_CTX_new error.\n");
return EXIT_FAILURE;
}
if (wolfSSL_CTX_load_verify_locations(ctx, certs, 0) != SSL_SUCCESS) {
fprintf(stderr, "Error loading %s, please check the file.\n", certs);
return EXIT_FAILURE;
}
ssl = wolfSSL_new(ctx);
if (ssl == NULL) {
printf("error: wolfSSL_new failed\n");
return EXIT_FAILURE;
}
sockfd = new_udp_client_socket(ssl, host);
if (sockfd <= 0) {
printf("error: new_udp_client_socket failed\n");
return EXIT_FAILURE;
}
if (wolfSSL_connect(ssl) != SSL_SUCCESS) {
err1 = wolfSSL_get_error(ssl, 0);
memset(buffer, 0, 80);
printf("err = %d, %s\n", err1, wolfSSL_ERR_error_string(err1, buffer));
printf("SSL_connect failed");
return EXIT_FAILURE;
}
/* Save the session */
session = wolfSSL_get1_session(ssl);
if (session == NULL) {
printf("error: get session failed\n");
return EXIT_FAILURE;
}
printf("info: saved session: %p\n", session);
ret = talk_to_server(ssl, "first client message");
if (ret) {
return EXIT_FAILURE;
}
/* Close the socket */
wolfSSL_shutdown(ssl);
wolfSSL_free(ssl);
close(sockfd);
ssl = NULL;
sockfd = 0;
/* Make a new WOLFSSL. */
ssl_res = wolfSSL_new(ctx);
if (ssl_res == NULL) {
printf("error: wolfSSL_new failed\n");
return EXIT_FAILURE;
}
/* Set up to resume the session */
ret = wolfSSL_set_session(ssl_res, session);
if (ret != WOLFSSL_SUCCESS) {
fprintf(stderr, "error: wolfSSL_set_session returned: %d\n", ret);
return EXIT_FAILURE;
}
/* Open a new udp socket. */
sockfd = new_udp_client_socket(ssl_res, host);
if (sockfd <= 0) {
printf("error: new_udp_client_socket failed\n");
return EXIT_FAILURE;
}
/* Test if the resume was successful */
if (wolfSSL_session_reused(ssl_res)) {
printf("info: session ID reused; Successful resume\n");
}
else {
printf("info: session ID not reused\n");
}
ret = talk_to_server(ssl_res, "client message after resume");
if (ret) {
return EXIT_FAILURE;
}
/* Cleanup memory used for storing the session information */
wolfSSL_shutdown(ssl_res);
wolfSSL_free(ssl_res);
wolfSSL_SESSION_free(session);
close(sockfd);
wolfSSL_CTX_free(ctx);
wolfSSL_Cleanup();
ssl_res = NULL;
session = NULL;
sockfd = 0;
return 0;
}
/* Given an ssl structure and host, open a new udp
* client socket and set it and the server address
* to the ssl.
**/
static int
new_udp_client_socket(WOLFSSL * ssl,
const char * host)
{
struct sockaddr_in servAddr;
int sockfd = 0;
int ret = 0;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd <= 0) {
int errsave = errno;
printf("error: socket returned %d\n", errsave);
return -1;
}
/* servAddr setup */
memset(&servAddr, 0, sizeof(servAddr));
servAddr.sin_family = AF_INET;
servAddr.sin_port = htons(SERV_PORT);
ret = inet_pton(AF_INET, host, &servAddr.sin_addr);
if (ret != 1) {
printf("error: inet_pton %s returned %d\n", host, ret);
close(sockfd);
sockfd = 0;
return -1;
}
ret = wolfSSL_dtls_set_peer(ssl, &servAddr, sizeof(servAddr));
if (ret != SSL_SUCCESS) {
printf("error: wolfSSL_dtls_set_peer returned %d\n", ret);
close(sockfd);
sockfd = 0;
return -1;
}
wolfSSL_set_fd(ssl, sockfd);
printf("info: opened socket: %d\n", sockfd);
return sockfd;
}
/* Send a message to the server.
**/
static int
talk_to_server(WOLFSSL * ssl,
const char * send_msg)
{
char recv_msg[MAXLINE];
int recv_len;
memset(recv_msg, 0, sizeof(recv_msg));
/* Attempt to send send_msg to the server */
if ( ( wolfSSL_write(ssl, send_msg, strlen(send_msg))) !=
strlen(send_msg) ) {
printf("Error: wolfSSL_write failed.\n");
return -1;
}
/* Attempt to read a message from server and store it in recv_msg */
recv_len = wolfSSL_read(ssl, recv_msg, sizeof(recv_msg) - 1);
/* Error checking wolfSSL_read */
if (recv_len < 0) {
int readErr = wolfSSL_get_error(ssl, 0);
if (readErr != SSL_ERROR_WANT_READ) {
printf("Error: wolfSSL_read failed.\n");
}
return -1;
}
recv_msg[recv_len] = '\0';
printf("info: server response: %s", recv_msg);
return 0;
}