Do more checking of command-line arguments

diff --git a/src/main/radsniff.c b/src/main/radsniff.c
index c9a0cd8..b7bb8fa 100644 (file)
--- a/src/main/radsniff.c
+++ b/src/main/radsniff.c
@@ -161,7 +161,7 @@ static void sort(RADIUS_PACKET *packet)
 }
 
 #define USEC 1000000
-static void tv_sub(struct timeval *end, struct timeval *start,
+static void tv_sub(const struct timeval *end, const struct timeval *start,
                   struct timeval *elapsed)
 {
        elapsed->tv_sec = end->tv_sec - start->tv_sec;
@@ -425,19 +425,23 @@ int main(int argc, char *argv[])
        /* Open the device so we can spy */
        if (filename) {
                descr = pcap_open_offline(filename, errbuf);
+       } else if (!dev) {
+               fprintf(stderr, "radsniff: No filename or device was specified.\n");
+               exit(1);
+
        } else {
                descr = pcap_open_live(dev, SNAPLEN, 1, 0, errbuf);
        }
        if (descr == NULL)
        {
-               printf("radsniff: pcap_open_live failed (%s)\n", errbuf);
+               fprintf(stderr, "radsniff: pcap_open_live failed (%s)\n", errbuf);
                exit(1);
        }
 
        /* Apply the rules */
        if( pcap_compile(descr, &fp, pcap_filter, 0, netp) == -1)
        {
-               printf("radsniff: pcap_compile failed\n");
+               fprintf(stderr, "radsniff: pcap_compile failed\n");
                exit(1);
        }
        if (pcap_setfilter(descr, &fp) == -1)