Add --print-sampling option to print every Nth packet

[tcpdump] / tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index a4403370e715b4c5b91e90bcd750f5a9565724a0..73e097196d85ef1c961e5581de28aa72dddbcd50 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -691,6 +691,7 @@ show_remote_devices_and_exit(void)
 #define OPTION_TSTAMP_NANO             134
 #define OPTION_FP_TYPE                 135
 #define OPTION_COUNT                   136
+#define OPTION_PRINT_SAMPLING          137
 
 static const struct option longopts[] = {
 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
@@ -738,6 +739,7 @@ static const struct option longopts[] = {
        { "fp-type", no_argument, NULL, OPTION_FP_TYPE },
        { "number", no_argument, NULL, '#' },
        { "print", no_argument, NULL, OPTION_PRINT },
+       { "print-sampling", required_argument, NULL, OPTION_PRINT_SAMPLING },
        { "version", no_argument, NULL, OPTION_VERSION },
        { NULL, 0, NULL, 0 }
 };
@@ -1960,6 +1962,14 @@ main(int argc, char **argv)
                        print = 1;
                        break;
 
+               case OPTION_PRINT_SAMPLING:
+                       print = 1;
+                       ++ndo->ndo_Sflag;
+                       ndo->ndo_print_sampling = atoi(optarg);
+                       if (ndo->ndo_print_sampling <= 0)
+                               error("invalid print sampling %s", optarg);
+                       break;
+
 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
                case OPTION_TSTAMP_MICRO:
                        ndo->ndo_tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;
@@ -3262,9 +3272,11 @@ print_usage(FILE *f)
 "\t\t" m_FLAG_USAGE "\n");
 #endif
        (void)fprintf(f,
-"\t\t[ -M secret ] [ --number ] [ --print ]" Q_FLAG_USAGE "\n");
+"\t\t[ -M secret ] [ --number ] [ --print ]\n");
+       (void)fprintf(f,
+"\t\t[ --print-sampling nth ]" Q_FLAG_USAGE " [ -r file ]\n");
        (void)fprintf(f,
-"\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ --version ]\n");
+"\t\t[ -s snaplen ] [ -T type ] [ --version ]\n");
        (void)fprintf(f,
 "\t\t[ -V file ] [ -w file ] [ -W filecount ] [ -y datalinktype ]\n");
 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION