diff --git a/ospfd/ospf_network.c b/ospfd/ospf_network.c
new file mode 100644
index 0000000..56ec864
--- /dev/null
+++ b/ospfd/ospf_network.c
@@ -0,0 +1,192 @@
+/*
+ * OSPF network related functions
+ *   Copyright (C) 1999 Toshiaki Takada
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include <zebra.h>
+
+#include "thread.h"
+#include "linklist.h"
+#include "prefix.h"
+#include "if.h"
+#include "sockunion.h"
+#include "log.h"
+#include "sockopt.h"
+
+#include "ospfd/ospfd.h"
+#include "ospfd/ospf_network.h"
+#include "ospfd/ospf_interface.h"
+#include "ospfd/ospf_asbr.h"
+#include "ospfd/ospf_lsa.h"
+#include "ospfd/ospf_lsdb.h"
+#include "ospfd/ospf_neighbor.h"
+#include "ospfd/ospf_packet.h"
+
+/* Join to the OSPF ALL SPF ROUTERS multicast group. */
+int
+ospf_if_add_allspfrouters (struct ospf *top, struct prefix *p,
+			   unsigned int ifindex)
+{
+  int ret;
+  
+  ret = setsockopt_multicast_ipv4 (top->fd, IP_ADD_MEMBERSHIP,
+                                   p->u.prefix4, htonl (OSPF_ALLSPFROUTERS),
+                                   ifindex);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_ADD_MEMBERSHIP (AllSPFRouters): %s",
+               strerror (errno));
+  else
+    zlog_info ("interface %s join AllSPFRouters Multicast group.",
+	       inet_ntoa (p->u.prefix4));
+
+  return ret;
+}
+
+int
+ospf_if_drop_allspfrouters (struct ospf *top, struct prefix *p,
+			    unsigned int ifindex)
+{
+  int ret;
+
+  ret = setsockopt_multicast_ipv4 (top->fd, IP_DROP_MEMBERSHIP,
+                                   p->u.prefix4, htonl (OSPF_ALLSPFROUTERS),
+                                   ifindex);
+  if (ret < 0)
+    zlog_warn("can't setsockopt IP_DROP_MEMBERSHIP (AllSPFRouters): %s",
+	      strerror (errno));
+  else
+    zlog_info ("interface %s leave AllSPFRouters Multicast group.",
+	       inet_ntoa (p->u.prefix4));
+
+  return ret;
+}
+
+/* Join to the OSPF ALL Designated ROUTERS multicast group. */
+int
+ospf_if_add_alldrouters (struct ospf *top, struct prefix *p, unsigned int
+			 ifindex)
+{
+  int ret;
+
+  ret = setsockopt_multicast_ipv4 (top->fd, IP_ADD_MEMBERSHIP,
+                                   p->u.prefix4, htonl (OSPF_ALLDROUTERS),
+                                   ifindex);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_ADD_MEMBERSHIP (AllDRouters): %s",
+               strerror (errno));
+  else
+    zlog_info ("interface %s join AllDRouters Multicast group.",
+	       inet_ntoa (p->u.prefix4));
+
+  return ret;
+}
+
+int
+ospf_if_drop_alldrouters (struct ospf *top, struct prefix *p, unsigned int
+			  ifindex)
+{
+  int ret;
+
+  ret = setsockopt_multicast_ipv4 (top->fd, IP_DROP_MEMBERSHIP,
+                                   p->u.prefix4, htonl (OSPF_ALLDROUTERS),
+                                   ifindex);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_DROP_MEMBERSHIP (AllDRouters): %s",
+	       strerror (errno));
+  else
+    zlog_info ("interface %s leave AllDRouters Multicast group.",
+	       inet_ntoa (p->u.prefix4));
+
+  return ret;
+}
+
+int
+ospf_if_ipmulticast (struct ospf *top, struct prefix *p, unsigned int ifindex)
+{
+  u_char val;
+  int ret, len;
+  
+  val = 0;
+  len = sizeof (val);
+  
+  /* Prevent receiving self-origined multicast packets. */
+  ret = setsockopt (top->fd, IPPROTO_IP, IP_MULTICAST_LOOP, (void *)&val, len);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_MULTICAST_LOOP(0): %s", strerror (errno));
+  
+  /* Explicitly set multicast ttl to 1 -- endo. */
+  val = 1;
+  ret = setsockopt (top->fd, IPPROTO_IP, IP_MULTICAST_TTL, (void *)&val, len);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_MULTICAST_TTL(1): %s", strerror (errno));
+
+  ret = setsockopt_multicast_ipv4 (top->fd, IP_MULTICAST_IF,
+                                   p->u.prefix4, 0, ifindex);
+  if (ret < 0)
+    zlog_warn ("can't setsockopt IP_MULTICAST_IF: %s", strerror (errno));
+
+  return ret;
+}
+
+int
+ospf_sock_init (void)
+{
+  int ospf_sock;
+  int ret, tos, hincl = 1;
+
+  ospf_sock = socket (AF_INET, SOCK_RAW, IPPROTO_OSPFIGP);
+  if (ospf_sock < 0)
+    {
+      zlog_warn ("ospf_read_sock_init: socket: %s", strerror (errno));
+      return -1;
+    }
+
+  /* Set precedence field. */
+#ifdef IPTOS_PREC_INTERNETCONTROL
+  tos = IPTOS_PREC_INTERNETCONTROL;
+  ret = setsockopt (ospf_sock, IPPROTO_IP, IP_TOS,
+		    (char *) &tos, sizeof (int));
+  if (ret < 0)
+    {
+      zlog_warn ("can't set sockopt IP_TOS %d to socket %d", tos, ospf_sock);
+      close (ospf_sock);	/* Prevent sd leak. */
+      return ret;
+    }
+#endif /* IPTOS_PREC_INTERNETCONTROL */
+
+  /* we will include IP header with packet */
+  ret = setsockopt (ospf_sock, IPPROTO_IP, IP_HDRINCL, &hincl, sizeof (hincl));
+  if (ret < 0)
+    zlog_warn ("Can't set IP_HDRINCL option");
+
+#if defined (IP_PKTINFO)
+  ret = setsockopt (ospf_sock, IPPROTO_IP, IP_PKTINFO, &hincl, sizeof (hincl));
+   if (ret < 0)
+    zlog_warn ("Can't set IP_PKTINFO option");
+#elif defined (IP_RECVIF)
+  ret = setsockopt (ospf_sock, IPPROTO_IP, IP_RECVIF, &hincl, sizeof (hincl));
+   if (ret < 0)
+    zlog_warn ("Can't set IP_RECVIF option");
+#else
+#warning "cannot be able to receive link information on this OS"
+#endif
+ 
+  return ospf_sock;
+}