Server and client dtls threaded examples.

Author: philljj

dtls/client-dtls-threaded.c

@@ -0,0 +1,269 @@
+/*
+ * client-dtls-threaded.c
+ *
+ * Copyright (C) 2006-2024 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
+ *
+ *=============================================================================
+ *
+ * A simple dtls client with configurable threadpool, for
+ * instructional/learning purposes. Utilizes DTLS 1.2.
+ */
+
+#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 MSGLEN          4096
+#define SERV_PORT       11111
+#define DTLS_NUMTHREADS 16
+
+typedef struct {
+    WOLFSSL *     ssl;
+    int           activefd;
+    WOLFSSL_CTX * ctx;
+} thread_args_t;
+
+static void     safer_shutdown(thread_args_t * args);
+static void *   client_work(void * arg);
+
+int
+main(int    argc,
+     char * argv[])
+{
+    WOLFSSL_CTX *   ctx = NULL; /* ctx shared by threads */
+    const char *    certs = "../certs/ca-cert.pem";
+    int             ret = 0;
+    int             n_threads = 2;
+    pthread_t       threads[DTLS_NUMTHREADS];
+    thread_args_t   args[DTLS_NUMTHREADS];
+    int             opt = 0;
+
+    memset(threads, 0, sizeof(threads));
+    memset(args, 0, sizeof(args));
+
+    while ((opt = getopt(argc, argv, "vt:n::?")) != -1) {
+        switch (opt) {
+        case 't':
+            n_threads = atoi(optarg);
+            break;
+
+        case '?':
+        default:
+            return EXIT_FAILURE;
+        }
+    }
+
+    if (n_threads <= 0 || n_threads > DTLS_NUMTHREADS) {
+        printf("error: invalid n_threads: %d\n", n_threads);
+        return EXIT_FAILURE;
+    }
+
+    /* Initialize wolfSSL before assigning ctx */
+    wolfSSL_Init();
+
+    ctx = wolfSSL_CTX_new(wolfDTLSv1_2_client_method());
+    if (ctx == NULL) {
+        printf("error: wolfSSL_CTX_new failed\n");
+        return EXIT_FAILURE;
+    }
+
+    /* Load certificates into ctx variable */
+    ret = wolfSSL_CTX_load_verify_locations(ctx, certs, 0);
+    if (ret != SSL_SUCCESS) {
+        printf("error: loading %s failed, please check the file\n", certs);
+        return EXIT_FAILURE;
+    }
+
+    for (size_t i = 0; i < n_threads; ++i) {
+        args[i].ctx = ctx;
+        ret = pthread_create(&threads[i], NULL, client_work, &args[i]);
+
+        if (ret == 0 ) {
+            printf("info: spawned thread: %ld\n", threads[i]);
+        }
+        else {
+            printf("error: pthread_create returned %d\n", ret);
+            threads[i] = 0;
+        }
+        sleep(1);
+    }
+
+    for (size_t i = 0; i < n_threads; ++i) {
+        if (threads[i]) {
+            pthread_join(threads[i], NULL);
+            printf("info: joined thread: %ld\n", threads[i]);
+            threads[i] = 0;
+        }
+    }
+
+    wolfSSL_CTX_free(ctx);
+    wolfSSL_Cleanup();
+
+    return EXIT_SUCCESS;
+}
+
+static void *
+client_work(void * args)
+{
+    thread_args_t * thread_args = (thread_args_t *) args;
+    int             n_bytes = 0;
+    int             err1;
+    struct          sockaddr_in servAddr;
+    char            send_msg[MSGLEN];
+    char            recv_msg[MSGLEN];
+    int             ret = 0;
+    const char *    localhost_ip = "127.0.0.1";
+
+    /* Assign ssl variable */
+    thread_args->ssl = wolfSSL_new(thread_args->ctx);
+    if (thread_args->ssl == NULL) {
+        printf("error: wolfSSL_new failed\n");
+        return NULL;
+    }
+
+    /* servAddr setup */
+    memset(&servAddr, 0, sizeof(servAddr));
+    servAddr.sin_family = AF_INET;
+    servAddr.sin_port = htons(SERV_PORT);
+
+    ret = inet_pton(AF_INET, localhost_ip, &servAddr.sin_addr);
+    if (ret != 1) {
+        printf("error: inet_pton %s returned %d\n", localhost_ip, ret);
+        return NULL;
+    }
+
+    ret = wolfSSL_dtls_set_peer(thread_args->ssl, &servAddr, sizeof(servAddr));
+    if (ret != SSL_SUCCESS) {
+        printf("error: wolfSSL_dtls_set_peer returned %d\n", ret);
+        return NULL;
+    }
+
+    thread_args->activefd = socket(AF_INET, SOCK_DGRAM, 0);
+    if (thread_args->activefd <= 0) {
+        printf("error: socket returned %d\n", thread_args->activefd);
+        return NULL;
+    }
+
+    /* Set the file descriptor for ssl and connect with ssl variable */
+    wolfSSL_set_fd(thread_args->ssl, thread_args->activefd);
+    if (wolfSSL_connect(thread_args->ssl) != SSL_SUCCESS) {
+        err1 = wolfSSL_get_error(thread_args->ssl, 0);
+        printf("error: thread %ld: wolfSSL_connect returned = %d, %s\n",
+                pthread_self(), err1,
+                wolfSSL_ERR_reason_error_string(err1));
+        return NULL;
+    }
+
+    /* Simulate a simple protocol over DTLS that exchanges a
+     * sequence of records, and checks we get correct records
+     * from correct server threads. */
+    long int     server_tid = 0;
+    const char * tid_str = NULL; /* Str to thread id in response. */
+
+    for (size_t i = 0; i < 4; ++i) {
+        char seq = '0' + (int) i;
+        sprintf(send_msg, "msg %zu from client thread %ld\n", i,
+                pthread_self());
+
+        n_bytes = wolfSSL_write(thread_args->ssl, send_msg, strlen(send_msg));
+
+        if (n_bytes != strlen(send_msg)) {
+            printf("error: wolfSSL_write returned %d", n_bytes);
+            break;
+        }
+
+        /* n is the # of bytes received */
+        n_bytes = wolfSSL_read(thread_args->ssl, recv_msg, sizeof(recv_msg)-1);
+
+        if (n_bytes < 0) {
+            printf("error: wolfSSL_read returned %d", n_bytes);
+            break;
+        }
+
+        recv_msg[n_bytes] = '\0';
+        fputs(recv_msg, stdout);
+
+        /* Check the server replied with the correct sequence record, e.g.:
+         *   "msg 2 from server thread 140146322425536" */
+        if (recv_msg[4] != seq) {
+            printf("error: got msg %c, expected %c\n", recv_msg[5], seq);
+            break;
+        }
+
+        tid_str = &recv_msg[25];
+        if (server_tid == 0) {
+            /* Save the server thread id on message 0. */
+            server_tid = atol(tid_str);
+        }
+        else {
+            /* Compare saved thread id. */
+            if (server_tid != atol(tid_str)) {
+                printf("error: got rsp from server thread %ld, expected %ld\n",
+                        server_tid, atol(tid_str));
+                break;
+            }
+            else {
+            printf("info: got response from server thread %ld\n",
+                        server_tid);
+            }
+        }
+
+        sleep(1);
+    }
+
+    safer_shutdown(thread_args);
+
+    return NULL;
+}
+
+/* Small shutdown wrapper to safely clean up a thread's
+ * connection. */
+static void
+safer_shutdown(thread_args_t * args)
+{
+    if (args == NULL) {
+        printf("error: safer_shutdown with null args\n");
+        return;
+    }
+
+    if (args->ssl != NULL) {
+        printf("info: closed tls session: %p\n", (void*) args->ssl);
+        wolfSSL_shutdown(args->ssl);
+        wolfSSL_free(args->ssl);
+        args->ssl = NULL;
+    }
+
+    if (args->activefd > 0) {
+        printf("info: closed socket: %d\n", args->activefd);
+        close(args->activefd);
+        args->activefd = 0;
+    }
+
+    return;
+}
+
+