Merge pull request #429 from mkirkhart/inverse-arp-print-fix

[tcpdump] / tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index b77b30818625a01fc555221e084d0e07bd5aa6bc..1eb2e206b6ec1b9a6a12eebc8f576117983aa9b1 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -669,6 +669,7 @@ show_devices_and_exit (void)
  */
 #define OPTION_VERSION         128
 #define OPTION_TSTAMP_PRECISION        129
+#define OPTION_IMMEDIATE_MODE  130
 
 static const struct option longopts[] = {
 #if defined(HAVE_PCAP_CREATE) || defined(WIN32)
@@ -700,6 +701,9 @@ static const struct option longopts[] = {
        { "packet-buffered", no_argument, NULL, 'U' },
 #endif
        { "linktype", required_argument, NULL, 'y' },
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+       { "immediate-mode", no_argument, NULL, OPTION_IMMEDIATE_MODE },
+#endif
 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
        { "debug-filter-parser", no_argument, NULL, 'Y' },
 #endif
@@ -736,7 +740,7 @@ droproot(const char *username, const char *chroot_dir)
                        fprintf(stderr, "error : ret %d\n", ret);
                }
                else {
-                       printf("dropped privs to %s\n", username);
+                       fprintf(stderr, "dropped privs to %s\n", username);
                }
                /* We don't need CAP_SETUID and CAP_SETGID */
                capng_updatev(
@@ -758,7 +762,7 @@ droproot(const char *username, const char *chroot_dir)
                        exit(1);
                }
                else {
-                       printf("dropped privs to %s\n", username);
+                       fprintf(stderr, "dropped privs to %s\n", username);
                }
 #endif /* HAVE_CAP_NG_H */
        }
@@ -948,6 +952,7 @@ main(int argc, char **argv)
        gndo->ndo_error=ndo_error;
        gndo->ndo_warning=ndo_warning;
        gndo->ndo_snaplen = DEFAULT_SNAPLEN;
+       gndo->ndo_immediate = 0;
 
        cnt = -1;
        device = NULL;
@@ -1355,6 +1360,12 @@ main(int argc, char **argv)
                        break;
 #endif
 
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+               case OPTION_IMMEDIATE_MODE:
+                       gndo->ndo_immediate = 1;
+                       break;
+#endif
+
                default:
                        print_usage();
                        exit(1);
@@ -1390,6 +1401,17 @@ main(int argc, char **argv)
        if (VFileName != NULL && RFileName != NULL)
                error("-V and -r are mutually exclusive.");
 
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+       /*
+        * If we're printing dissected packets to the standard output
+        * rather than saving raw packets to a file, and the standard
+        * output is a terminal, use immediate mode, as the user's
+        * probably expecting to see packets pop up immediately.
+        */
+       if (WFileName == NULL && isatty(1))
+               gndo->ndo_immediate = 1;
+#endif
+
 #ifdef WITH_CHROOT
        /* if run as root, prepare for chrooting */
        if (getuid() == 0 || geteuid() == 0) {
@@ -1515,6 +1537,15 @@ main(int argc, char **argv)
                                pcap_statustostr(status));
 #endif
 
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+               if (gndo->ndo_immediate) {
+                       status = pcap_set_immediate_mode(pd, 1);
+                       if (status != 0)
+                               error("%s: Can't set immediate mode: %s",
+                               device,
+                               pcap_statustostr(status));
+               }
+#endif
                /*
                 * Is this an interface that supports monitor mode?
                 */
@@ -2533,6 +2564,9 @@ print_usage(void)
        (void)fprintf(stderr, "[ --time-stamp-precision precision ]\n");
        (void)fprintf(stderr,
 "\t\t");
+#endif
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+       (void)fprintf(stderr, "[ --immediate-mode ] ");
 #endif
        (void)fprintf(stderr, "[ -T type ] [ --version ] [ -V file ]\n");
        (void)fprintf(stderr,