Cleanups to CAN bus

* Add warnings to CFLAGS (except for isotp)
* Fix items found by warnings
* Remove %.*s usage
* Fix indentation issue
* Use WOLFSSL_* instead of SSL_* constants
* Switch to TLS v1.3
* Add missing wolfSSL_Cleanup()

can-bus/Makefile

@@ -1,6 +1,6 @@
 CC=gcc
 LIBS=-lwolfssl
-CFLAGS=-ggdb3 -Iisotp-c -Wno-cpp
+CFLAGS=-Iisotp-c -Wno-cpp -Wall -Wextra -Wdeclaration-after-statement
 
 COMMON_OBJS=isotp-c/isotp.o common.o
 CLIENT_OBJS=client.o
@@ -8,6 +8,9 @@ SERVER_OBJS=server.o
 
 all: client server
 
+isotp-c/isotp.o: isotp-c/isotp.c
+	@$(CC) -c $< -o $@
+
 %.o: %.c
 	@$(CC) -c $< -o $@ $(CFLAGS)
 

can-bus/README.md

@@ -35,32 +35,26 @@ server vcan0
 On the client you will see (byte numbers will vary):
 
 ```
-Sending 164 bytes
+Sending 242 bytes
-Receiving 95 bytes
+Receiving 128 bytes
-Receiving 954 bytes
+Receiving 28 bytes
-Receiving 338 bytes
+Receiving 974 bytes
-Receiving 9 bytes
+Receiving 286 bytes
-Sending 75 bytes
+Receiving 58 bytes
-Sending 6 bytes
+Sending 58 bytes
-Sending 45 bytes
-Receiving 6 bytes
-Receiving 45 bytes
 SSL handshake done!
 ```
 
 And on the server:
 
 ```
-Receiving 164 bytes
+Receiving 242 bytes
-Sending 95 bytes
+Sending 128 bytes
-Sending 954 bytes
+Sending 28 bytes
-Sending 338 bytes
+Sending 974 bytes
-Sending 9 bytes
+Sending 286 bytes
-Receiving 75 bytes
+Sending 58 bytes
-Receiving 6 bytes
+Receiving 58 bytes
-Receiving 45 bytes
-Sending 6 bytes
-Sending 45 bytes
 SSL handshake done!
 ```
 
@@ -69,22 +63,18 @@ Once you see the message "SSL handshake done!" on both consoles you can enter te
 For example, on the client if we type "Hello world, this is a TLS test!":
 
 ```
-Hello world, this is a TLS test!
+Hello world! This is a CAN bus test!
+Sending: Hello world! This is a CAN bus test!
 
-Sending: Hello world, this is a TLS test!
+Sending 59 bytes
-
-
-Sending 62 bytes
 Message sent
 ```
 
 The server will echo:
 
 ```
-Receiving 62 bytes
+Receiving 59 bytes
-
+Got message: Hello world! This is a CAN bus test!
-
-Got message: Hello world, this is a TLS test!
 ```
 
 ## Cleaning Up

can-bus/client.c

@@ -28,8 +28,6 @@ int main(int argc, char *argv[])
     WOLFSSL_CTX *ctx = NULL;
     WOLFSSL_METHOD* method = NULL;
     WOLFSSL* ssl = NULL;
-    uint8_t data[CAN_MSG_LEN];
-    int length;
     int ret;
 
     if (argc != 2) {
@@ -53,7 +51,7 @@ int main(int argc, char *argv[])
         ssize_t line_size = 0;
         line_size = getline(&line, &len, stdin);
         if (line_size > 0) {
-            printf("\nSending: %.*s\n\n", (int)line_size, line);
+            printf("Sending: %s\n", line);
             wolfSSL_send(ssl, line, line_size, 0);
             printf("Message sent\n");
         }

can-bus/common.c

@@ -74,6 +74,7 @@ int isotp_user_send_can(const uint32_t arbitration_id, const uint8_t* data,
 /* Our CAN bus receive function */
 int can_receive(uint8_t data[CAN_MSG_LEN], int *length) {
     int nbytes;
+    int ret;
     struct can_frame frame;
     struct pollfd p[1];
 
@@ -81,13 +82,13 @@ int can_receive(uint8_t data[CAN_MSG_LEN], int *length) {
     p[0].events = POLLIN;
 
     /* Poll for new data */
-	int retval = poll(p, 1, 10);
+    ret = poll(p, 1, 10);
 
-    if (retval < 0) {
+    if (ret < 0) {
         perror("Poll error\n");
         return 1;
     }
-    else if (retval == 0) {
+    else if (ret == 0) {
         /* No data */
         *length = 0;
         return EAGAIN;
@@ -159,7 +160,8 @@ int send_ssl(WOLFSSL *ssl, char *buf, int sz, void *ctx)
     uint8_t data[CAN_MSG_LEN];
     int length;
     IsoTpLink *g_link = (struct IsoTpLink*)ctx;
-    int ret = isotp_send(g_link, buf, sz);
+    int ret = isotp_send(g_link, (uint8_t*)buf, sz);
+    (void) ssl;
     printf("Sending %d bytes\n", sz);
 
     if (ret) {
@@ -189,8 +191,8 @@ int recv_ssl(WOLFSSL* ssl, char* buf, int sz, void* ctx)
     uint8_t data[CAN_MSG_LEN];
     int data_len;
     uint16_t msg_len = 0;
-    int ret;
     IsoTpLink *g_link = (struct IsoTpLink*)ctx;
+    (void) ssl;
 
     if (!copy_buf_len) {
         while (isotp_receive(g_link, copy_buf, ISOTP_BUFSIZE, &msg_len)
@@ -213,7 +215,7 @@ int recv_ssl(WOLFSSL* ssl, char* buf, int sz, void* ctx)
         }
     }
 
-    if (copy_buf_len >= sz) {
+    if (copy_buf_len >= (size_t)sz) {
         memcpy(buf, copy_buf_ptr, sz);
         copy_buf_ptr+= sz;
         copy_buf_len-= sz;
@@ -231,11 +233,11 @@ int recv_ssl(WOLFSSL* ssl, char* buf, int sz, void* ctx)
 void close_ssl(WOLFSSL_CTX *ctx, WOLFSSL *ssl)
 {
     if (ssl) {
-        int ret = SSL_SHUTDOWN_NOT_DONE;
+        int ret = WOLFSSL_SHUTDOWN_NOT_DONE;
-        while (ret == SSL_SHUTDOWN_NOT_DONE) {
+        while (ret == WOLFSSL_SHUTDOWN_NOT_DONE) {
             ret = wolfSSL_shutdown(ssl);
         }
-        if (ret != SSL_SUCCESS) {
+        if (ret != WOLFSSL_SUCCESS) {
             char buffer[ERR_MSG_LEN];
             int err = wolfSSL_get_error(ssl, ret);
             fprintf(stderr, "Error shutting down TLS connection: %d, %s",
@@ -247,10 +249,12 @@ void close_ssl(WOLFSSL_CTX *ctx, WOLFSSL *ssl)
 
     wolfSSL_free(ssl);
     wolfSSL_CTX_free(ctx);
+    wolfSSL_Cleanup();
 }
 
 void sig_handle(int dummy)
 {
+    (void) dummy;
     keep_running = 0;
 }
 
@@ -283,9 +287,9 @@ int setup_ssl(enum service_type type, WOLFSSL_CTX **new_ctx,
     WOLFSSL* ssl = NULL;
 
     if (type == SERVICE_TYPE_CLIENT) {
-        method = wolfTLSv1_2_client_method();
+        method = wolfTLSv1_3_client_method();
     } else {
-        method = wolfTLSv1_2_server_method();
+        method = wolfTLSv1_3_server_method();
     }
 
     if (!method) {
@@ -311,10 +315,10 @@ int setup_ssl(enum service_type type, WOLFSSL_CTX **new_ctx,
         ret = wolfSSL_CTX_load_verify_locations(ctx, "client.pem", NULL);
     } else {
         ret = wolfSSL_CTX_use_certificate_file(ctx, "server.pem",
-                SSL_FILETYPE_PEM);
+                WOLFSSL_FILETYPE_PEM);
     }
 
-    if (ret != SSL_SUCCESS) {
+    if (ret != WOLFSSL_SUCCESS) {
         fprintf(stderr, "ERROR: failed to load cert, "
                 "please check the file.\n");
         close_ssl(ctx, NULL);
@@ -323,7 +327,7 @@ int setup_ssl(enum service_type type, WOLFSSL_CTX **new_ctx,
 
     if (type == SERVICE_TYPE_SERVER) {
         if ((ret = wolfSSL_CTX_use_PrivateKey_file(ctx, "server.key",
-                        SSL_FILETYPE_PEM)) != WOLFSSL_SUCCESS) {
+                        WOLFSSL_FILETYPE_PEM)) != WOLFSSL_SUCCESS) {
             fprintf(stderr, "ERROR: failed to load key file, "
                     "please check the file.\n");
             close_ssl(ctx, NULL);
@@ -350,7 +354,7 @@ int setup_ssl(enum service_type type, WOLFSSL_CTX **new_ctx,
 
     wolfSSL_set_using_nonblock(ssl, 1);
 
-    if (ret != SSL_SUCCESS) {
+    if (ret != WOLFSSL_SUCCESS) {
         char buffer[ERR_MSG_LEN];
         int err = wolfSSL_get_error(ssl, ret);
         fprintf(stderr, "ERROR: failed to connect using wolfSSL: %d, %s\n",

can-bus/common.h

@@ -38,6 +38,7 @@
 #include <signal.h>
 
 #include <isotp.h>
+#include <wolfssl/options.h>
 #include <wolfssl/ssl.h>
 
 #define ISOTP_BUFSIZE 16384

can-bus/server.c

@@ -21,6 +21,8 @@
 
 #include "common.h"
 
+#define RECV_MSG_LEN 64
+
 extern volatile int keep_running;
 
 int main(int argc, char *argv[])
@@ -46,10 +48,12 @@ int main(int argc, char *argv[])
     }
 
     while(keep_running) {
-        char reply[64];
+        int input;
-        int input = wolfSSL_read(ssl, reply, sizeof(reply));
+        char reply[RECV_MSG_LEN];
+        memset(reply, 0, RECV_MSG_LEN);
+        input = wolfSSL_read(ssl, reply, RECV_MSG_LEN);
         if (input > 0) {
-            printf("\n\nGot message: %.*s\n", input, reply);
+            printf("Got message: %s\n", reply);
         }
     }