diff --git a/Makefile b/Makefile
index 5680393..ee45db4 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ OBJS = \
 CC = gcc
 LD = gcc
 RM = rm -rf
-PKGS = gstreamer-1.0
+PKGS = gstreamer-1.0 gio-2.0
 CFLAGS = -I. `pkg-config --cflags $(PKGS)` `pcap-config --cflags`
 CFLAGS += -std=gnu99 -W -Wall -Wno-unused-result -pedantic
 CFLAGS += -DOMVS_VERSION=\"$(OMVS_VERSION)\"
diff --git a/omvs_main.c b/omvs_main.c
index 6a07d24..090d281 100644
--- a/omvs_main.c
+++ b/omvs_main.c
@@ -1,4 +1,6 @@
+#include <string.h>
 #include <pcap.h>
+#include <gio/gio.h>
 #include <gst/gst.h>
 
 static gchar *_omvs_net_dev;
@@ -36,14 +38,26 @@ typedef struct _OMVSIPAddr {
 typedef struct _OMVSScanner {
   OMVSIPAddr *ipaddrs;
   gint num_ipaddrs;
-  gint scan_ipaddr_idx;
-  gint scan_port_idx;
 } OMVSScanner;
 
+static gint _omvs_start_scan(OMVSScanner *scanner);
+
+static gint _omvs_start_scan(OMVSScanner *scanner) {
+  gint i;
+  for (i = 0; i < scanner->num_ipaddrs; i++) {
+    g_print("%08x\n", scanner->ipaddrs[i].addr);
+  }
+  return 0;
+}
+
 int main(int argc, char *argv[]) {
   GError *error = NULL;
   GOptionContext *context;
   int ret = 0;
+  gint i;
+  gint num_ipaddrs;
+  gint idx_ipaddr;
+  OMVSScanner omvs_scanner;
 
   context = g_option_context_new("<multicast ip address or net ... [#N]>");
   g_option_context_set_summary(context,
@@ -70,6 +84,77 @@ int main(int argc, char *argv[]) {
     goto finish_return;
   }
 
+  num_ipaddrs = 0;
+  for (i = 1; i < argc; i++) {
+    GInetAddressMask *mask;
+    GInetAddress *addr;
+    guint len;
+    mask = g_inet_address_mask_new_from_string(argv[i], &error);
+    if (!mask) {
+      g_print("%s parsing failed: %s\n", argv[i], error->message);
+      ret = -3;
+      goto finish_return;
+    }
+    if (g_inet_address_mask_get_family(mask) != G_SOCKET_FAMILY_IPV4) {
+      g_print("%s is not ipv4 ip address\n", argv[i]);
+      g_object_unref(mask);
+      ret = -4;
+      goto finish_return;
+    }
+    addr = g_inet_address_mask_get_address(mask);
+    if (!g_inet_address_get_is_multicast(addr)) {
+      g_print("%s is not multicast ip address\n", argv[i]);
+      g_object_unref(mask);
+      ret = -4;
+      goto finish_return;
+    }
+    len = g_inet_address_mask_get_length(mask);
+    if (len) {
+      num_ipaddrs += (1 << (32 - len));
+    } else {
+      num_ipaddrs++;
+    }
+    g_object_unref(mask);
+  }
+
+  memset(&omvs_scanner, 0, sizeof(OMVSScanner));
+  omvs_scanner.ipaddrs = g_malloc0(num_ipaddrs * sizeof(OMVSIPAddr));
+  omvs_scanner.num_ipaddrs = num_ipaddrs;
+
+  idx_ipaddr = 0;
+  for (i = 1; i < argc; i++) {
+    GInetAddressMask *mask;
+    GInetAddress *addr;
+    guint len;
+    guint32 start_ipaddr;
+    const guint8 *addr_bytes;
+    mask = g_inet_address_mask_new_from_string(argv[i], &error);
+    addr = g_inet_address_mask_get_address(mask);
+    len = g_inet_address_mask_get_length(mask);
+    addr_bytes = g_inet_address_to_bytes(addr);
+    start_ipaddr =
+      (((guint32)addr_bytes[0]) << 24) |
+      (((guint32)addr_bytes[1]) << 16) |
+      (((guint32)addr_bytes[2]) << 8) |
+      (((guint32)addr_bytes[3]) << 0);
+    if (len) {
+      guint n;
+      guint j;
+      n = (1 << (32 - len));
+      for (j = 0; j < n; j++) {
+        omvs_scanner.ipaddrs[idx_ipaddr].addr = start_ipaddr;
+        idx_ipaddr++;
+        start_ipaddr++;
+      }
+    } else {
+      omvs_scanner.ipaddrs[idx_ipaddr].addr = start_ipaddr;
+      idx_ipaddr++;
+    }
+  }
+
+  _omvs_start_scan(&omvs_scanner);
+  g_free(omvs_scanner.ipaddrs);
+
 finish_return:
   g_option_context_free(context);