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wolfssl-examples/dtls/server-dtls-nonblocking.c

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/* server-dtls-nonblocking.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 nonblocking DTLS server for instructional/learning
* purposes. Utilizes DTLS 1.2.
*/
#include <wolfssl/options.h>
#include <stdio.h> /* standard in/out procedures */
#include <stdlib.h> /* defines system calls */
#include <string.h> /* necessary for memset */
#include <netdb.h>
#include <sys/socket.h> /* used for all socket calls */
#include <netinet/in.h> /* used for sockaddr_in */
#include <arpa/inet.h>
#include <wolfssl/ssl.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#define SERV_PORT 11111 /* define our server port number */
#define MSGLEN 4096
static int cleanup; /* To handle shutdown */
void sig_handler(const int sig);
/* costumes for select_ret to wear */
enum {
TEST_SELECT_FAIL,
TEST_TIMEOUT,
TEST_RECV_READY,
TEST_ERROR_READY
};
/* For handling ^C interrupts passed by the user */
void sig_handler(const int sig)
{
printf("\nSIGINT %d handled\n", sig);
cleanup = 1;
return;
}
int main(int argc, char** argv)
{
/* cont short for "continue?", Loc short for "location" */
int cont = 0;
char caCertLoc[] = "../certs/ca-cert.pem";
char servCertLoc[] = "../certs/server-cert.pem";
char servKeyLoc[] = "../certs/server-key.pem";
WOLFSSL_CTX* ctx;
/* Await Datagram variables */
int on = 1;
int res = 1;
int recvLen; /* length of string read */
int readWriteErr;
int listenfd = 0; /* Initialize our socket */
int clientfd = 0; /* client connection */
int len = sizeof(on);
char buff[MSGLEN]; /* string read from client */
WOLFSSL* ssl = NULL; /* Initialize ssl object */
struct sockaddr_in servAddr; /* our server's address */
char ack[] = "I hear you fashizzle\n";
/* DTLS set nonblocking flag */
int flags = fcntl(*(&listenfd), F_GETFL, 0);
/* NonBlockingSSL_Accept variables */
int ret;
int select_ret;
int currTimeout = 0;
int error;
int result;
int nfds;
fd_set recvfds, errfds;
struct timeval timeout;
/* udp-read-connect variables */
int bytesRecvd;
unsigned char b[MSGLEN];
struct sockaddr_in cliAddr;
socklen_t clilen;
/* Code for handling signals */
struct sigaction act, oact;
act.sa_handler = sig_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
sigaction(SIGINT, &act, &oact);
/* "./config --enable-debug" and uncomment next line for debugging */
/* wolfSSL_Debugging_ON(); */
/* Initialize wolfSSL */
wolfSSL_Init();
/* Set ctx to DTLS 1.2 */
if ((ctx = wolfSSL_CTX_new(wolfDTLSv1_2_server_method())) == NULL) {
printf("wolfSSL_CTX_new error.\n");
return 1;
}
/* Load CA certificates */
if (wolfSSL_CTX_load_verify_locations(ctx,caCertLoc,0) !=
SSL_SUCCESS) {
printf("Error loading %s, please check the file.\n", caCertLoc);
return 1;
}
/* Load server certificates */
if (wolfSSL_CTX_use_certificate_file(ctx, servCertLoc, SSL_FILETYPE_PEM) !=
SSL_SUCCESS) {
printf("Error loading %s, please check the file.\n", servCertLoc);
return 1;
}
/* Load server Keys */
if (wolfSSL_CTX_use_PrivateKey_file(ctx, servKeyLoc,
SSL_FILETYPE_PEM) != SSL_SUCCESS) {
printf("Error loading %s, please check the file.\n", servKeyLoc);
return 1;
}
/*****************************************************************************/
/* AwaitDatagram code */
cont = 0;
while (cleanup != 1) {
clilen = sizeof(cliAddr);
timeout.tv_sec = (currTimeout > 0) ? currTimeout : 0;
/* Create a UDP/IP socket */
if ((listenfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
printf("Cannot create socket.\n");
cont = 1;
}
printf("Socket allocated\n");
/* DTLS set nonblocking */
if (flags < 0) {
printf("fcntl get failed");
cleanup = 1;
}
flags = fcntl(*(&listenfd), F_SETFL, flags | O_NONBLOCK);
if (flags < 0) {
printf("fcntl set failed.\n");
cleanup = 1;
}
/* Clear servAddr each loop */
memset((char *)&servAddr, 0, sizeof(servAddr));
/* host-to-network-long conversion (htonl) */
/* host-to-network-short conversion (htons) */
servAddr.sin_family = AF_INET;
servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
servAddr.sin_port = htons(SERV_PORT);
/* Eliminate socket already in use error */
res = setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, len);
if (res < 0) {
printf("Setsockopt SO_REUSEADDR failed.\n");
cont = 1;
}
/*Bind Socket*/
if (bind(listenfd,
(struct sockaddr *)&servAddr, sizeof(servAddr)) < 0) {
printf("Bind failed.\n");
cont = 1;
}
printf("Awaiting client connection on port %d\n", SERV_PORT);
/* UDP-read-connect */
bytesRecvd = 0;
do {
if (cleanup == 1) {
cont = 1;
break;
}
bytesRecvd = (int)recvfrom(listenfd, (char*)b, sizeof(b), MSG_PEEK,
(struct sockaddr*)&cliAddr, &clilen);
} while (bytesRecvd <= 0);
if (bytesRecvd > 0) {
if (connect(listenfd, (const struct sockaddr*)&cliAddr,
sizeof(cliAddr)) != 0) {
printf("udp connect failed.\n");
}
}
else {
printf("recvfrom failed.\n");
}
printf("Connected!\n");
/* ensure b is empty upon each call */
memset(&b, 0, sizeof(b));
clientfd = listenfd;
/* Create the WOLFSSL Object */
if (( ssl = wolfSSL_new(ctx)) == NULL) {
printf("wolfSSL_new error.\n");
cont = 1;
}
/* set clilen to |cliAddr| */
printf("Connected!\n");
/* set the/ session ssl to client connection port */
wolfSSL_set_fd(ssl, clientfd);
wolfSSL_dtls_set_using_nonblock(ssl, 1);
/*****************************************************************************/
/* NonBlockingDTLS_Connect code */
ret = wolfSSL_accept(ssl);
currTimeout = 1;
error = wolfSSL_get_error(ssl, 0);
listenfd = (int)wolfSSL_get_fd(ssl);
nfds = listenfd + 1;
while (cleanup != 1 && (ret != SSL_SUCCESS &&
(error == SSL_ERROR_WANT_READ ||
error == SSL_ERROR_WANT_WRITE))) {
if (cleanup == 1) {
wolfSSL_free(ssl);
wolfSSL_shutdown(ssl);
break;
}
if (error == SSL_ERROR_WANT_READ)
printf("... server would read block\n");
else
printf("... server would write block\n");
currTimeout = wolfSSL_dtls_get_current_timeout(ssl);
FD_ZERO(&recvfds);
FD_SET(listenfd, &recvfds);
FD_ZERO(&errfds);
FD_SET(listenfd, &errfds);
result = select(nfds, &recvfds, NULL, &errfds, &timeout);
select_ret = TEST_SELECT_FAIL;
if (result == 0) {
select_ret = TEST_TIMEOUT;
}
else if (result > 0) {
if (FD_ISSET(listenfd, &recvfds)) {
select_ret = TEST_RECV_READY;
}
else if(FD_ISSET(listenfd, &errfds)) {
select_ret = TEST_ERROR_READY;
}
}
if ((select_ret == TEST_RECV_READY) ||
(select_ret == TEST_ERROR_READY)) {
ret = wolfSSL_accept(ssl);
error = wolfSSL_get_error(ssl, 0);
}
else if (select_ret == TEST_TIMEOUT && !wolfSSL_dtls(ssl)) {
error = SSL_ERROR_WANT_READ;
}
else if (select_ret == TEST_TIMEOUT && wolfSSL_dtls(ssl) &&
wolfSSL_dtls_got_timeout(ssl) >= 0) {
error = SSL_ERROR_WANT_READ;
}
else {
error = SSL_FATAL_ERROR;
}
}
if (ret != SSL_SUCCESS) {
printf("SSL_accept failed with %d.\n", ret);
cont = 1;
}
else {
cont = 0;
}
if (cont != 0) {
printf("NonBlockingSSL_Accept failed.\n");
cont = 1;
}
/* end NonBlockingDTLS_Connect code */
/*****************************************************************************/
/* Begin: Reply to the client */
recvLen = wolfSSL_read(ssl, buff, sizeof(buff)-1);
/* Begin do-while read */
readWriteErr = 0;
do {
if (cleanup == 1) {
memset(buff, 0, sizeof(buff));
break;
}
if (recvLen < 0) {
readWriteErr = wolfSSL_get_error(ssl, 0);
if (readWriteErr != SSL_ERROR_WANT_READ) {
printf("Read Error, error was: %d.\n", readWriteErr);
cleanup = 1;
}
else {
recvLen = wolfSSL_read(ssl, buff, sizeof(buff)-1);
}
}
} while (readWriteErr == SSL_ERROR_WANT_READ &&
recvLen < 0 &&
cleanup != 1);
/* End do-while read */
if (recvLen > 0) {
buff[recvLen] = 0;
printf("I heard this:\"%s\"\n", buff);
}
else {
printf("Connection Timed Out.\n");
}
/* Begin do-while write */
do {
if (cleanup == 1) {
memset(&buff, 0, sizeof(buff));
break;
}
readWriteErr = wolfSSL_get_error(ssl, 0);
if (wolfSSL_write(ssl, ack, sizeof(ack)) < 0) {
printf("Write error.\n");
cleanup = 1;
}
printf("Reply sent:\"%s\"\n", ack);
} while(readWriteErr == SSL_ERROR_WANT_WRITE && cleanup != 1);
/* End do-while write */
/* free allocated memory */
memset(buff, 0, sizeof(buff));
wolfSSL_free(ssl);
/* End: Reply to the Client */
}
/* End await datagram code */
/*****************************************************************************/
if (cont == 1 || cleanup == 1) {
wolfSSL_CTX_free(ctx);
wolfSSL_Cleanup();
}
return 0;
}
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