397 lines
13 KiB
C
397 lines
13 KiB
C
/* server-dtls-callback.c
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*
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* Copyright (C) 2006-2020 wolfSSL Inc.
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*
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* This file is part of wolfSSL. (formerly known as CyaSSL)
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*
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* wolfSSL is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* wolfSSL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*
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*=============================================================================
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*
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* Bare-bones example of a DTLS server for instructional/learning purposes.
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* Utilizes DTLS 1.2 and custom IO callbacks.
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*/
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#ifndef WOLFSSL_USER_SETTINGS
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#include <wolfssl/options.h>
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#endif
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#include <wolfssl/wolfcrypt/settings.h>
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#include <wolfssl/ssl.h>
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#include <stdio.h> /* standard in/out procedures */
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#include <stdlib.h> /* defines system calls */
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#include <string.h> /* necessary for memset */
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#include <netdb.h>
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#include <sys/socket.h> /* used for all socket calls */
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#include <netinet/in.h> /* used for sockaddr_in */
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#include <arpa/inet.h>
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#include <errno.h>
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#include <signal.h>
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#include <unistd.h>
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#define SERV_PORT 11111 /* define our server port number */
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#define MSGLEN 4096
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#define DTLS_MTU 1500
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static int cleanup = 0; /* To handle shutdown */
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static void sig_handler(const int sig)
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{
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printf("\nSIGINT %d handled\n", sig);
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cleanup = 1;
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return;
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}
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typedef struct SharedDtls {
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WOLFSSL* ssl; /* WOLFSSL object being shared */
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int sd; /* socket fd */
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struct sockaddr_in cliAddr; /* server sockaddr */
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socklen_t cliSz; /* length of servAddr */
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byte rxBuf[DTLS_MTU];
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} SharedDtls;
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int my_IORecv(WOLFSSL* ssl, char* buff, int sz, void* ctx)
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{
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SharedDtls* shared = (SharedDtls*)ctx;
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int recvd;
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int dtls_timeout;
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printf("Server Recv fd %d, buf %d\n", shared->sd, sz);
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dtls_timeout = wolfSSL_dtls_get_current_timeout(ssl);
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/* If we are performing the DTLS handshake, and we are in blocking mode, we
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* set a socket timeout at OS level. */
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if (!wolfSSL_is_init_finished(ssl)) {
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/* Still in handshake: set the OS timeout */
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if (dtls_timeout > 0) {
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struct timeval tv;
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tv.tv_sec = dtls_timeout;
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tv.tv_usec = 0;
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if (setsockopt(shared->sd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0) {
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fprintf(stderr, "setsockopt failed\n");
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return WOLFSSL_CBIO_ERR_GENERAL;
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}
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}
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} else {
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struct timeval tv = {0, 0};
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if (setsockopt(shared->sd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0) {
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fprintf(stderr, "setsockopt failed\n");
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return WOLFSSL_CBIO_ERR_GENERAL;
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}
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}
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/* Receive datagram and store client's address */
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recvd = recvfrom(shared->sd, buff, sz, 0, (struct sockaddr*)&shared->cliAddr, &shared->cliSz);
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if (recvd == -1) {
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/* error encountered. Be responsible and report it in wolfSSL terms */
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fprintf(stderr, "IO RECEIVE ERROR: %d\n", errno);
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switch (errno) {
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#if EAGAIN != EWOULDBLOCK
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case EAGAIN: /* EAGAIN == EWOULDBLOCK on some systems, but not others */
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#endif
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case EWOULDBLOCK:
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if (!wolfSSL_dtls(ssl) || wolfSSL_get_using_nonblock(ssl)) {
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fprintf(stderr, "would block\n");
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return WOLFSSL_CBIO_ERR_WANT_READ;
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}
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else {
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fprintf(stderr, "socket timeout\n");
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return WOLFSSL_CBIO_ERR_TIMEOUT;
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}
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case ECONNRESET:
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fprintf(stderr, "connection reset\n");
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return WOLFSSL_CBIO_ERR_CONN_RST;
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case EINTR:
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fprintf(stderr, "socket interrupted\n");
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cleanup = 1;
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return WOLFSSL_CBIO_ERR_GENERAL;
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/* NOTE: Don't return WOLFSSL_CBIO_ERR_ISR. It keeps trying to recv */
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case ECONNREFUSED:
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fprintf(stderr, "connection refused\n");
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return WOLFSSL_CBIO_ERR_WANT_READ;
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case ECONNABORTED:
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fprintf(stderr, "connection aborted\n");
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return WOLFSSL_CBIO_ERR_CONN_CLOSE;
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default:
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fprintf(stderr, "general error\n");
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return WOLFSSL_CBIO_ERR_GENERAL;
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}
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}
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else if (recvd == 0) {
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printf("Connection closed\n");
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return WOLFSSL_CBIO_ERR_CONN_CLOSE;
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}
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/* successful receive */
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printf("my_IORecv: received %d bytes from %d\n", recvd, shared->sd);
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return recvd;
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}
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int my_IOSend(WOLFSSL* ssl, char* buff, int sz, void* ctx)
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{
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SharedDtls* shared = (SharedDtls*)ctx;
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int sent;
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const struct sockaddr* addr = NULL;
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socklen_t addrSz = 0;
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if (shared) {
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addr = (const struct sockaddr*)&shared->cliAddr;
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addrSz = shared->cliSz;
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}
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printf("Server Send fd %d, sz %d\n", shared->sd, sz);
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/* Send datagram */
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sent = sendto(shared->sd, buff, sz, 0, addr, addrSz);
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if (sent == -1) {
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/* error encountered. Be responsible and report it in wolfSSL terms */
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fprintf(stderr, "IO SEND ERROR: %d\n", errno);
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switch (errno) {
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#if EAGAIN != EWOULDBLOCK
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case EAGAIN: /* EAGAIN == EWOULDBLOCK on some systems, but not others */
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#endif
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case EWOULDBLOCK:
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fprintf(stderr, "would block\n");
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return WOLFSSL_CBIO_ERR_WANT_READ;
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case ECONNRESET:
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fprintf(stderr, "connection reset\n");
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return WOLFSSL_CBIO_ERR_CONN_RST;
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case EINTR:
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fprintf(stderr, "socket interrupted\n");
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cleanup = 1;
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return WOLFSSL_CBIO_ERR_GENERAL;
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/* NOTE: Don't return WOLFSSL_CBIO_ERR_ISR. It keeps trying to send */
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case EPIPE:
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fprintf(stderr, "socket EPIPE\n");
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return WOLFSSL_CBIO_ERR_CONN_CLOSE;
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default:
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fprintf(stderr, "general error\n");
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return WOLFSSL_CBIO_ERR_GENERAL;
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}
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}
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else if (sent == 0) {
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printf("Connection closed\n");
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return 0;
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}
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/* successful send */
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printf("my_IOSend: sent %d bytes to %d\n", sent, shared->sd);
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return sent;
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}
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int main(int argc, char** argv)
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{
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int ret = 0, err;
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const char caCertLoc[] = "../certs/ca-cert.pem";
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const char servCertLoc[] = "../certs/server-cert.pem";
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const char servKeyLoc[] = "../certs/server-key.pem";
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WOLFSSL_CTX* ctx = NULL;
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WOLFSSL* ssl = NULL;
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char buff[MSGLEN]; /* the incoming message */
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int buffLen;
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int listenfd = -1; /* Initialize our socket */
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int on;
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socklen_t len;
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SharedDtls shared;
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struct sockaddr_in servAddr;
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/* Code for handling signals */
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struct sigaction act, oact;
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act.sa_handler = sig_handler;
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sigemptyset(&act.sa_mask);
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act.sa_flags = 0;
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sigaction(SIGINT, &act, &oact);
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/* "./config --enable-debug" and uncomment next line for debugging */
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wolfSSL_Debugging_ON();
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/* Initialize wolfSSL */
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wolfSSL_Init();
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/* Set ctx to DTLS 1.2 */
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if ((ctx = wolfSSL_CTX_new(wolfDTLSv1_2_server_method())) == NULL) {
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printf("wolfSSL_CTX_new error.\n");
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ret = -1;
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goto exit;
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}
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/* Load CA certificates */
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ret = wolfSSL_CTX_load_verify_locations(ctx, caCertLoc, NULL);
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if (ret != SSL_SUCCESS) {
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printf("Error loading %s, please check the file.\n", caCertLoc);
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goto exit;
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}
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/* Load server certificates */
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ret = wolfSSL_CTX_use_certificate_file(ctx, servCertLoc, SSL_FILETYPE_PEM);
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if (ret != SSL_SUCCESS) {
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printf("Error loading %s, please check the file.\n", servCertLoc);
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goto exit;
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}
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/* Load server Keys */
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ret = wolfSSL_CTX_use_PrivateKey_file(ctx, servKeyLoc, SSL_FILETYPE_PEM);
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if (ret != SSL_SUCCESS) {
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printf("Error loading %s, please check the file.\n", servKeyLoc);
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goto exit;
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}
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/* Register callbacks */
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wolfSSL_CTX_SetIORecv(ctx, my_IORecv);
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wolfSSL_CTX_SetIOSend(ctx, my_IOSend);
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/* Await Datagram */
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while (cleanup == 0) {
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/* Create a UDP/IP socket */
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ret = socket(AF_INET, SOCK_DGRAM, 0);
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if (ret < 0 ) {
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printf("Cannot create socket %d.\n", ret);
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goto exit;
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}
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listenfd = ret;
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printf("Socket allocated\n");
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/* setup servAddr */
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memset(&servAddr, 0, sizeof(servAddr));
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servAddr.sin_family = AF_INET;
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servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
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servAddr.sin_port = htons(SERV_PORT);
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/* Eliminate socket already in use error */
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on = 1;
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len = sizeof(on);
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ret = setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, len);
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if (ret < 0) {
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printf("Setsockopt SO_REUSEADDR failed %d.\n", errno);
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goto exit;
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}
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/* Bind Socket */
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ret = bind(listenfd, (struct sockaddr*)&servAddr, sizeof(servAddr));
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if (ret < 0) {
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printf("Bind failed %d.\n", errno);
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goto exit;
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}
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printf("Awaiting client connection on port %d\n", SERV_PORT);
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memset(&shared, 0, sizeof(shared));
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shared.sd = listenfd;
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shared.cliSz = sizeof(shared.cliAddr);
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/*
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* Wait until the socket is readable
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* and wait until we actually have data waiting to be read.
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* */
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{
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fd_set readfds;
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FD_ZERO(&readfds);
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FD_SET(listenfd, &readfds);
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/* No timeout, so wait indefinitely */
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int sel_ret = select(listenfd + 1, &readfds, NULL, NULL, NULL);
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if (sel_ret < 0) {
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perror("select");
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goto exit;
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}
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}
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/* Create the WOLFSSL Object */
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if ((ssl = wolfSSL_new(ctx)) == NULL) {
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printf("wolfSSL_new error.\n");
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break;
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}
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shared.ssl = ssl;
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wolfSSL_SetIOWriteCtx(ssl, &shared);
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wolfSSL_SetIOReadCtx(ssl, &shared);
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if (wolfSSL_accept(ssl) != SSL_SUCCESS) {
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err = wolfSSL_get_error(ssl, 0);
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printf("error = %d, %s\n", err, wolfSSL_ERR_reason_error_string(err));
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printf("SSL_accept failed.\n");
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wolfSSL_shutdown(ssl);
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wolfSSL_free(ssl);
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ssl = NULL;
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close(listenfd);
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listenfd = -1;
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continue;
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}
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/* echo until shutdown received */
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while (cleanup == 0 && ret == 0) {
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buffLen = 0;
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ret = wolfSSL_read(ssl, buff, sizeof(buff)-1);
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if (ret > 0) {
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printf("heard %d bytes\n", ret);
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buffLen = ret;
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buff[buffLen] = '\0';
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printf("I heard this: \"%s\"\n", buff);
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ret = 0;
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}
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else {
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err = wolfSSL_get_error(ssl, 0);
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if (err != SSL_ERROR_WANT_READ) {
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printf("error = %d, %s\n", err, wolfSSL_ERR_reason_error_string(err));
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printf("SSL_read failed.\n");
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break;
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}
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}
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printf("Sending echo reply\n");
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ret = wolfSSL_write(ssl, buff, buffLen);
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if (ret < 0) {
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err = wolfSSL_get_error(ssl, 0);
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if (err != SSL_ERROR_WANT_WRITE) {
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printf("error = %d, %s\n", err, wolfSSL_ERR_reason_error_string(err));
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printf("wolfSSL_write fail.\n");
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break;
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}
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}
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ret = 0; /* success */
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}
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wolfSSL_free(ssl);
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ssl = NULL;
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close(listenfd);
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listenfd = -1;
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printf("Client done, waiting for next connection\n");
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}
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exit:
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if (ssl) {
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wolfSSL_shutdown(ssl);
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wolfSSL_free(ssl);
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}
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if (listenfd != -1) {
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close(listenfd);
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}
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if (ctx) {
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wolfSSL_CTX_free(ctx);
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}
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wolfSSL_Cleanup();
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return ret;
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}
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