Merge 0cfff2e5da into 6b46063eee

isotpsniffer.c

@@ -59,6 +59,7 @@
 #include <linux/can.h>
 #include <linux/can/isotp.h>
 #include <linux/sockios.h>
+#include <errno.h>
 
 #define NO_CAN_ID 0xFFFFFFFFU
 
@@ -66,6 +67,8 @@
 #define FORMAT_ASCII 2
 #define FORMAT_DEFAULT (FORMAT_ASCII | FORMAT_HEX)
 
+#define PDU_BUF_SIZE 4096
+
 void print_usage(char *prg)
 {
 	fprintf(stderr, "\nUsage: %s [options] <CAN interface>\n", prg);
@@ -79,6 +82,7 @@ void print_usage(char *prg)
 	fprintf(stderr, "         -f <format>  (1 = HEX, 2 = ASCII, 3 = HEX & ASCII - default: %d)\n", FORMAT_DEFAULT);
 	fprintf(stderr, "         -L           (set link layer options for CAN FD)\n");
 	fprintf(stderr, "         -h <len>     (head: print only first <len> bytes)\n");
+	fprintf(stderr, "         -i           (ignore syscall errors to receive malformed PDUs)\n");
 	fprintf(stderr, "\nCAN IDs and addresses are given and expected in hexadecimal values.\n");
 	fprintf(stderr, "\n");
 }
@@ -189,15 +193,16 @@ int main(int argc, char **argv)
 	int head = 0;
 	int timestamp = 0;
 	int format = FORMAT_DEFAULT;
+	int ignore_errors = 0;
 	canid_t src = NO_CAN_ID;
 	canid_t dst = NO_CAN_ID;
 	extern int optind, opterr, optopt;
 	static struct timeval tv, last_tv;
 
-	unsigned char buffer[4096];
+	unsigned char buffer[PDU_BUF_SIZE];
 	int nbytes;
 
-	while ((opt = getopt(argc, argv, "s:d:x:X:h:ct:f:L?")) != -1) {
+	while ((opt = getopt(argc, argv, "s:d:x:X:h:ct:f:L?i")) != -1) {
 		switch (opt) {
 		case 's':
 			src = strtoul(optarg, NULL, 16);
@@ -249,6 +254,10 @@ int main(int argc, char **argv)
 			}
 			break;
 
+		case 'i':
+			ignore_errors = 1;
+			break;
+
 		case '?':
 			print_usage(basename(argv[0]));
 			goto out;
@@ -367,33 +376,39 @@ int main(int argc, char **argv)
 		}
 
 		if (FD_ISSET(s, &rdfs)) {
-			nbytes = read(s, buffer, 4096);
+			nbytes = read(s, buffer, PDU_BUF_SIZE);
 			if (nbytes < 0) {
 				perror("read socket s");
 				r = 1;
-				goto out;
+				if(!ignore_errors)
+					goto out;
 			}
-			if (nbytes > 4095) {
+			if (nbytes > (PDU_BUF_SIZE - 1)) {
 				r = 1;
+				fprintf(stderr, "PDU length %d longer than PDU buffer: %s\n", nbytes, strerror(errno));
 				goto out;
 			}
-			printbuf(buffer, nbytes, color?2:0, timestamp, format,
-				 &tv, &last_tv, dst, s, if_name, head);
+			if(nbytes > 0)
+				printbuf(buffer, nbytes, color?2:0, timestamp, format,
+					 &tv, &last_tv, dst, s, if_name, head);
 		}
 
 		if (FD_ISSET(t, &rdfs)) {
-			nbytes = read(t, buffer, 4096);
+			nbytes = read(t, buffer, PDU_BUF_SIZE);
 			if (nbytes < 0) {
 				perror("read socket t");
 				r = 1;
-				goto out;
+				if(!ignore_errors)
+					goto out;
 			}
-			if (nbytes > 4095) {
+			if (nbytes > (PDU_BUF_SIZE - 1)) {
 				r = 1;
+				fprintf(stderr, "PDU length %d longer than PDU buffer: %s\n", nbytes, strerror(errno));
 				goto out;
 			}
-			printbuf(buffer, nbytes, color?1:0, timestamp, format,
-				 &tv, &last_tv, src, t, if_name, head);
+			if(nbytes > 0)
+				printbuf(buffer, nbytes, color?1:0, timestamp, format,
+					 &tv, &last_tv, src, t, if_name, head);
 		}
 	}